Speciality
Spotlight

 




 


Neurosurgery


 

      



  • JP
    Leonetti, T Origitano, et al
    (Loyola Univ, Maywood, III)

    Intracranial Complications of Temporal Bone Osteoradionecrosis.

    Am
    J Otol 18:223-229, 1997

        

    Osteoradionecrosis
    of the temporal bone may follow
    radiation to the brain, parotid
    gland, nasopharynx, or superior
    cervical area. 
    Life-threatening
    intracranial complications may
    follow.

        

    In 4 patients studied,
    complications observed were
    multiple brain abscesses,
    aneurysm of the internal carotid
    artery; a cholesteatoma of the
    external auditory canal with
    extensive destruction of the
    mastoid bone leading to
    thrombosis and meningitis of the
    sigmoid sinus; meningitis with a
    small epidural abscess over the
    middle fossa dura; and prolonged
    infection of the ear canal,
    middle ear, and mastoid
    resulting in fatal otitic
    meningitis.
    The 3 patients who
    underwent surgery (mastoid)
    survived requiring careful and
    regular follow-up.

        

  • PA
    Fagan, JP Sheehy, et al (St.
    Vincent’s Hosp, Sydney,
    Australia)

    The
    Cerebellopontine Angle: Does the
    Translabyrinthine Approach Give
    Adequate Access?

    Laryngoscope 108: 679-682, 1998

        

    It was previously believed
    that the translabyrinthine
    approach provided inadequate
    access to the cerebellopontine
    angle.
    The authors after
    analyzing 33 patients undergoing
    translabyrinthine surgery and 13
    undergoing the posterior fossa
    approach have concluded
    that the translabyrinthine
    approach enables superior
    visualization through a wider
    angle of surgical access with
    minimal cerebellar retraction. 


        

  • HM
    Dunniway, DB Welling (Ohio State
    Univ, Columbus)

    Intracranial
    Tumors Mimicking Benign
    Paroxysmal Positional Vertigo.

    Otolaryngol Head Neck Surg, 118:429-436, 1998.

        

    Benign positional vertigo
    may not always be benign, as
    indicated in this study where
    intracranial tumors were
    identified in five patients who
    presented as “benign
    paroxysmal vertigo.”

        

    When patients of “benign
    paroxysmal vertigo” do not
    improve after particle
    repositioning manoeuver, further
    assessment is needed to rule out
    intracranial new growths.

         

  • RC
    O’Reilly, SB Kapadia,  D.B. Kamerer (Univ of Pittsburgh, Pa)

    Primary
    Extracranial Meningioma of the
    Temporal Bone.

    Otolaryngol Head Neck Surg  118:690-694,
    1998.

        

    Though meningiomas typically
    occur intracranially, they may
    rarely arise de novo in the
    temporal bone.  Because of the invasive nature of this tumor, surgical
    resection is difficult, and
    postoperative surveillance is
    necessary
    .



  • Michael
    L, Rosenberg, MD, and Martin
    Gizzi, MD, PhD From the New
    Jersey Neuroscience Institute,
    Edison, New Jersy,

    Neuro-Otologic
    History

    Otolaryngologic
    Clinics of North America, Volume
    33, No.3 June 2000, Pg. 471- 482

       

    A
    complete description of the
    patient’s symptoms is crucial
    for the diagnosis.

     

    Definition
    of Terms : Vertigo, Visual
    Disorientation, Lightheadedness,
    and Imbalance

      

    1.   
    Vertigo is the illusory
    sensation of motion.True vertigo
    is caused by pathology in the
    peripheral end organ, the
    vestibular   nerve,
    the vestibular nuclei, the
    cerebellum, and the pathways
    that connect them in the
    brainstem and, rarely, the
    cortex.

     

    2.   
    Visual disorientation may
    mimic acute ataxia. A second,
    but related, from of visual
    disorientation is the disruption
    of depth perception associated
    with new onset strabismus.

     

    3.   
    Lightheadedness term
    should be reserved for symptoms
    similar to those preceding
    syncope. Lightheadedness is
    presumably caused by cerebral
    hypoxia, and may be cardiac or
    vasovagal in origin.

     

    4.   
    Imbalance, is the
    inability to maintain the center
    of gravity and affected patients
    note unsteadiness, stumbling,
    and falling.

      

    Precipitating
    Factors

     

    Vertigo brought on by
    lying supine and turning to one
    side is typical of benign
    paroxysmal positional vertigo [BPPV]
    . Lightheadedness brought on by
    getting up quickly from a lying
    or sitting position.

     

    Patients
    with BPPV also may have brief
    vertigo and nystagmus on sitting
    up quickly.

     

    Patients with cerebellar disease
    may remain symptomatic as long
    as they remain in that position.

     

    Patients with motor balance
    disorders, related to cerebellar
    degeneration or to parkinsonism,
    usually report symptoms only
    when walking.

     

    DURATION OF SYMPTOMS

     

    Fleeting

     

    Vertigo lasting only a few
    seconds is most likely related
    to a fixed vestibular lesion,
    such as follows vestibular
    neuronitis or the late stages of
    Meniere’s disease.

     

    Seconds

      

    Symptoms lasting from 5 to
    90 seconds are typical of BPPV,
    but most last less than 15
    seconds.

        

    Minutes

     

    Attacks of vertigo lasting 2
    to 20 minutes are consistent
    with a transient ischemic attack
    [TIA] affecting the posterior
    circulation.

     

    Characteristically, posterior
    circulation TIAs are accompanied
    by diplopia, visual field
    defects, ataxia, hemisensory
    loss, or hemiparesis.

     

    Hours

     

    The major attacks of
    Meniere’s disease last 20
    minutes to 24 hours, but most
    commonly last 4 to 8 hours.

     

    Migraine may present as vertigo
    lasting minutes or hours.

     

    Acoustic neuroma is an
    uncommon cause of vertigo as it
    is a chronic condition and
    damage to vestibular fibers is
    compensated for quickly.

     

    Days

     

    An isolated attack of
    vertigo lasting more than 24
    hours is strongly suggestive of
    vestibular neuronitis.

     

    Vertigo usually lasts 2 to 3
    days but occasionally up to a
    week.

     

    Vertigo lasting more than 3 days
    is often seen in acute central
    nervous system disease.

     

    A continuous sensation of
    vertigo lasting longer than 1 or
    2 weeks without daily variation
    is probably a psychogenic
    phenomenon.

     

    Vertigo of vestibular origin
    probably cannot persist on a
    physiologic basis for more than
    2 weeks.

     

    Associated
    Otologic Complaints

     

    Otologic complaints, such as
    hearing loss, tinnitus, or ear
    fullness, provide important
    clues as to the location of a
    lesion.

     

    Episodic
    tinnitus with fluctuating
    hearing loss may make the
    diagnosis of Meniere’s
    disease.

     

    Classically,
    patients with Meniere’s
    disease experience increased
    tinnitus and worsening of
    hearing loss during the time of
    vertigo attack.

     

    Pain associated with vestibular
    symptoms should raise suspicion
    of middle ear disease; however,
    it also may be associated with
    invasive disease of the temporal
    bone and with meningeal
    irritation.

     

    Visual
    function

     

    All sensory information [
    other than taste and smell] can
    be used to give information
    about position and velocity
    relative to the surround.

     

    Vision, in particular, is used
    to stabilize the world. 
    It can suppress strongly
    any nystagmus and the sense of
    motion generated by the
    vestibular system.

     

    In the dark the visual system
    can no longer provide the
    stabilizing information.

     

    A
    normal person has no difficulty
    relying on vestibular
    information in such situations,
    but a patient with a vestibular
    imbalance may report that the
    world is moving.

        



        

  • JA 
    Gastel, MA Palumbo, MJ
    Hulstyn, et al (Brown Univ,
    Providence, Rl)

    Emergency
    Removal of Football Equipment: A
    Cadaveric Cervical Spine Injury
    Model.

    Ann Emerg Med 32: 411-417, 1998.

       

    Purpose: The proper early
    management of suspected cervical
    spine injuries in football
    players is critical.
    EMT’s are trained to
    remove the helmet to avoid
    hyperflexion of the neck but
    sports medicine experts
    recommend against this practice.
    A cadaver study was
    conducted to analyse the effects
    of a football helmet or shoulder
    pads on alignment of the
    unstable cervical spine.

         

    Methods:
    The study included 8 cadavers of
    average age 73 years.
    A simulated bilateral
    facet dislocation was created at
    C5-C6 motion segment.
    Lateral x-rays were taken
    before and after injury with
    cadaver wearing (1) no equipment
    (2) a helmet only (3) shoulder
    pads only and (4) a helmet and
    shoulder pads.
    The effect of the
    alignment of the cervical spine
    was studied.

         

    Results:
    Lordosis was decreased by 9.6
    degrees with helmet only and
    increased 13.6 degrees with
    shoulder pads only.

         

    After destabilisation of the
    cervical spine, C5-C6 forward
    angulation was increased by 16.5
    degrees with helmet only and the
    posterior disc space height was
    increased by 3.8mm and dorsal
    element distraction by 8.3 mm.
    In the other 3
    indications there were no
    significant differences.

        

    Conclusions:
    The results suggest that the
    helmet and shoulder pads should
    be left in place until the
    patient reaches a hospital
    unless CPR is required.

        

  • WF
    Donaldson III, WC Lauerman, B
    Heil, et al (Univ of Pittsburgh,
    Pa)

    Helmet
    and Shoulder Pad Removal From a
    Player With Suspected Cervical
    Spine Injury: A Cadaveric Model.

    Spine 23: 1729-1733, 1998.

         

    Objective: Cervical spine
    injuries can result in
    quadriplegia.
    The problem of removing
    the helmet and shoulder pads of
    an injured football player has
    been debated.
    A cadaver model was used
    to study how much motion occurs
    with 2 types of injuries when a
    helmet and shoulder pads are
    removed.

         

    Methods:
    Transoral osteotomy at waist of
    odontoid process was done to
    render C1-C2 unstable in 3
    cadavers and in another 3
    cadavers, the interspinous
    ligaments, the facet capsules,
    posterior longitudinal ligaments
    and posterior one third of the
    disc were sectioned at C5-C6. 
    Under fluoroscopic
    visualization, 4 people removed
    the helmets by first removing
    the facemask, then the chinstrap
    and then the ear-pieces.
    The shoulder pads were
    then removed.
    Maximum displacements
    were recorded and analysed.

         

    Results:
    Instability at C2 resulted in a
    change in angulation of 5.47
    degrees distraction of 2.98 mm
    and a change in space available
    for the cord by 3.91 mm when the
    helmet was removed.
    With removal of shoulder
    pads, the change in angulation
    was 2.9 degrees distraction
    1.76mm and the change in the
    space available for the cord
    2.64 mm.

        

    Conclusions:
    A significant amount of movement
    can occur in an unstable
    cervical spine when the helmet
    and shoulder pads are removed.
    Therefore, it would be
    unwise to try to remove the
    helmet and shoulder pads before
    transportation to hospital.

         

  • MJ
    Wetzler, T Akpata, W Laughlin,
    et al (American Orthopaedic
    Rugby Football Assoc, Washington
    Crossing, Pa; South Jersey
    Orthopedic Associates, Voorhees,
    NJ: Rugby Magazine,
    New York; et al )

    Occurrence
    of Cervical Spine Injuries
    During the Rugby Scrum

    Am J Sports Med 26: 177-180, 1998.

         

    Objective:
    The scrum is responsible for 60%
    of cervical spine injuries in
    rugby. 
    The cause and reduction
    of cervical spine injuries
    during the rugby scrum were
    studied retrospectively.

      

    Methods:
    Data on 62 injured players was
    compiled from oral and written
    reports and from medical
    records.

        

    Results: 
    Between 1970 and 1996, 36
    (58%) players sustaining a
    cervical spine injury were
    injured during a scrum with
    23(64%) occurring during the
    engagement and 13 (36%) during
    the collapse of the scrum.

        

    Players injured during
    the engagement were hookers
    (22%), props (11%) and a second
    row player (3%).
    There were 21 (58%)
    senior level players and 15(42%)
    junior level players.
    Nine (25%) occurred as a
    result of a mismatch
    inexperience.

        

    Conclusion:
    Cervical spine injuries to rugby
    players occur more frequently
    during the engagement phase of
    the scrum, to hookers, and to
    lower level players.

  • Joel
    A, Goebel, MD, FACS From the
    Department of
    Otolaryngology,Washington
    University School of Medicine,
    St. Louis, Missouri

    Management Options for Acute
    Versus Chronic Vertigo

    Volume 33, No.33, June
    2000, Pg. 483-493

     

    Vertigo
    is one of the most frequent and
    disturbing sensations that the
    practicing otolaryngologist is
    called upon to treat.

     

    Vertigo is defined as a false
    illusion of motion with a
    distinct rotational component.

     

    Recurrent
    attacks of vertigo are addressed
    as chronic vertigo.

     

    Rotational
    chair tests explore the VOR and
    visual-vestibular interaction.

     

    CPD is used in cases of postural
    instability to document patterns
    of sensory organization and
    motor control during various
    visual and support-surface
    challenges.

     

    THERAPEUTIC
    OPTIONS

     

    Medical
    Therapy

     

    Most medications for acute
    attacks of vertigo are centrally
    acting suppressants for nausea
    and vomiting.

     

    For acute spells, diazepam 2 to
    5 mg three times daily works
    well. Meclizine 25 mg three
    times daily and promethazine 25
    to 50 mg every 8 hours is
    another useful combination.
    Tapered steroid regimen is
    useful in early vestibular
    neuritis. They are not to be
    used chronically or for
    prophylaxis against subsequent
    attacks.

     

    Surgical
    Therapy

     
     

    Candidates for surgical
    therapy represent a small
    fraction [< 5%] of all dizzy
    patients.

     

    Surgical procedures for vertigo
    can be described by two
    characteristics -
    ablative/non-ablative and
    hearing preserving/hearing
    destroyed.

     

    Ablative procedures include
    transmastoid labyrinthectomy and
    vestibular nerve section.

     

    In many centers, transtympanic
    gentamicin therapy has
    dramatically reduced the
    necessity for surgical ablation.

     

    Non-ablative
    procedures include endolymphatic
    sac decompression, endolymphatic
    sac shunt, and posterior canal
    occlusion.

        



         

  • Alexiadou-Rudolf
    C, Ernestus R-1, Nanassis K, et
    al [Univ of Thessaloniki,
    Greece]

    Acute
    Nontraumatic Spinal Epidural
    Hematomas : An Important
    Differential Diagnosis in Spinal
    Emergencies


    Spine
    23: 1810-1813, 1998

     
     

    Fewer
    than 1% of spinal epidural
    space-occupying lesions are
    spontaneous spinal epidural
    hematomas [SSEHs], a rare spinal
    emergency that can be difficult
    to recognize.

       

    Good outcomes require an
    accurate diagnosis and prompt
    surgical decompression.

       

    Most cases occur in the lumbar
    region and dorsal to the spinal
    cord.

       

    The typical history is acute,
    nontraumatic onset of local
    pain, with signs of spinal cord
    compression occurring within
    hours.

       

    The differential
    diagnosis includes spinal
    abscess, tumor, ischemia,
    transverse myelitis, and acute
    vertebral disk disease, but the
    time spent on diagnostic tests
    may reduce the chance of a good
    outcome.

       

    Patients with SSEH present with
    rapidly progressive sensorimotor
    paralysis or cauda equina
    syndrome.

       

    Good postoperative function can
    be expected only if the patient
    is operated on within 12 hours
    after onset of symptoms.

       

    MRI
    is the diagnostic method of
    choice and shows signal behavior
    identical to that of
    intracerebral hematoma. Spinal
    MRI should be performed as
    quickly as possible to avoid
    diagnostic delays.

        

  • MS
    Abdou, AR Cohen (Case Western Reserve Univ, Cleveland, Ohio) :
    Endoscopic Treatment of colloid Cysts of the third Ventricle: Technical Note and Review of the Literature.

      J Neurosurg 89:1062-1068, 1998.

         

    In some patients, colloid cysts may obstruct the foramina of Monro, resulting in hydrocephalus, intracranial hypertension and neurologic dysfunction. A technique for
    endoscopic management of colloid cysts and its outcomes were reported.

        

    Endoscopic surgery allows wide fenestration of the capsule and aspiration of the cyst contents under direct vision, with minimal disruption of the cortex and other normal brain structures. The endoscope is the ideal instrument for exploring fluid-filled cavities. The intraventricular location of colloid cysts makes these lesions especially accessible.

         

  • T
    Menovsky, JA Grotenhuis, J de Vries, et al (Univ Hosp of Nijmegen, The Netherlands) 

    Endoscope-assisted Supraorbital Craniotomy for Lesions of the Interpeduncular
    Fossa.

      Neurosurgery 44: 106-112, 1999.

        

    The supraorbital approach is accepted for lesions in the anterior fossa, the sellar region and the anterior part of the circle of Willis. However, for lesions in the interpeduncular fossa, this approach has not been widely used. The use of an endoscope allows a bright and excellent view into the interpeduncular fossa, necessary for a minimally invasive supraorbital approach.

        

    With this technique, the surgical route is nearly perpendicular, the amount of dissection and brain retraction minimized, and the surgical incision is small

         

  • EJ Kosnik (Ohio State Univ, Columbus; Children’s Hosp, Columbus, Ohio) :

    Use of Ligamentum Nuchae Graft for Dural Closure in Posterior Fossa Surgery :
    Technical Note.

      J Neurosurg 89:155-156, 1998. 

         

    In posterior fossa surgery, watertight dural closure helps to support the cerebellum and to prevent contamination of the CSF. 

        

    Excellent results were achieved by the authors, using ligamentum nuchae graft for watertight dural closure in patients undergoing posterior fossa surgery. There have
    been no problems with CSF leakage or pseudomeningoceles. 

         

    The ligamentum nuchae provides a safe, effective and readily available material for closure of posterior fossa dural defects.

           

  • DA
    Hollander, NJ Volpe, et al (Univ
    of Pennysylvania School of
    Medicine; Albert Einstein
    Hospital, Philadelphia)

    Use of a portable head
    mounted perimetry system to
    assess bedside visual fields.

    BJO 2000; 84: 1185-1190

      

    The authors describe a head
    mounted, AUTOMATED perimetry
    system, which is portable and
    convenient for examining
    neurosurgical patients at their
    bedside in the perioperative
    period.

      

    The method offers standardised,
    quantifiable testing with
    graphic results for follow-up
    examinations. 

       

    The device showed equal
    sensitivity to methods of
    confrontation field testing, in
    detecting field defects.

       

  • D.N.
    Parmar, A.Sofat, R. Bowman, et
    al (Department of Neurosciences,
    King’s College Hospital, London)

    Visual prognostic value of
    the pattern electroretinogram in
    chiasmal compression.

    Br.J.Ophthalmol 2000: 84:
    1024-1026.


      

    The visual loss caused by
    chiasmal (optic) compression by
    pituitary tumours may be
    transient or permanent. This is
    possibly related to the extent
    of irreversible retrograde
    degeneration of the retinal
    ganglion cells.

      

    The pattern electroretinogram (PERG)
    N95 component is believed to
    rise in relation to retinal
    ganglion cell function and may
    be a potential prognostic
    indicator for visual function
    following decompressive surgery.

       

    Records of 72 eyes from 36
    patients were retrospectively
    analysed. It was concluded that
    the PERG is a useful visual
    prognostic indicator in the
    preoperative assessment of
    chiasmal compression.

        

  • P. Chang, Los Angeles, USA.

    Controversies in Vestibular Schwannoma Treatment: Surgery versus Irradiation.

    ENT News, 9(5), Nov./Dec.2000, p.14-15

        


    Cropping of these controversies has been because of irradiation as an alternative to surgery. Microsurgery is the present day choice for vestibular schwannoma.

         

    The following questions arise in the critical minds of patients:

    a) What is the expected morbidity of surgery?

    b) Is hearing preservation possible?

    c) Can benign tumour be irradiated without any long-term side effects?

    d) How effective radiation is?

    e) Are the results competitive to that of surgery. Will all be judged in justifying the alternative treatment of Vestibular Schwannoma?

         


    Tumour: 


    Vestibular schwannoma tumours arise from neural sheaths and are benign. Their situation in internal auditory canal and cerebellopontine angle, make them dangerous by position. The tumour consists of nothing but proliferating Schwann cells, which is very slow viz. 1 to 2 mm per year. Majority grows producing progressive hearing loss. This growth however, exceptionally can be unpredictable. That is why in fit patient, intervention is required. Technological advances in early precise diagnosis by imaging techniques and advances in management have proved the surgical outcomes much favourable.

         

    However, technological advances in radiotherapy have also offered an alternative treatment.

         


    Surgical Background:


    It has come a long way from removal of tumour by finger, by Balance in London in 1894 to perfection of precise removal by translabyrinthine, retrosigmoid and middle fossa approaches derived by Dr. William House in 1964, almost without mortality and minimal of morbidity. Today there is likelihood of complete removal with zero mortality rate, near normal facial nerve function in 95% and less than 0.3% recurrence rate and 70% rate of preservation of hearing in selected patient makes the treatment by surgical excision treatment of choice.

          

    The negative points are that it is intracranial procedure with its attendant risks of C.S.F leak, meningitis and intracranial bleed. It incurs cost and 4-5 days of hospitalization.

         

    Today the treatment by radiation may be opted to (a) Medically unfit patients (b) Recurrent tumours (c) Elderly patients (d) Who refuse surgery. The use of radiotherapy as primary mode of treatment of vestibular schwannoma has also been promoted.

         


    Background of Radiotherapy


    Lars Leksell (1971) at Sweden (Karolinska Institute in Stockholm) first reported gamma radiation ports administered stereotactically during a single sitting to arrest the tumour growth.

         

    The principle is to target the lesion, minimising, the radiation dose to surrounding neural tissues. The term “stereotactic radiosurgery” was coined and particular technique used was called the ‘gamma knife’.

         

    The treatment evolved in last decades. The radiation dosage of 25Gy has been reduced optimally to 13Gy delivered by Linear accelerator and is now fractionate. This has resulted into improvement in tumour control and preservation of normal neural tissue.

         


    The Controversy


    – Because of close relations of tumour capsule to 7th and 8th nerve, it is impossible to avoid radiation to these nerves.

         

    – The effects of radiation are cell deaths and delayed vasculitis. Vasculitis is not observed because of sparse blood supply as against seen in glomus.

        

    – Subsequent surgical intervention, if required in these irradiated tumour, lead to hazzardous dissection resulting in poor hearing and facial nerve function.

        

    So the alternative treatment is reserved for those patients who are unfit or unwilling to undergo microsurgical removal of tumour.

        

  • Andras A Kemeny, Royal Hallamshire Hospital, Sheffield, England

    What is the role of radiosurgery in Vestibular Schwannoma treatment?

    ENT News, Nov/Dec.2000, vol.9(5), p.19

        

    It is a surgical technique, the concentrated radiation is achieved by crossfiring 201 fine gamma ray beams focused into a single point. Initially with poor imaging and slow computers, this was difficult to achieve. But with the introduction of high resolution, volume acquisition MR imaging and powerful 3D computational software the true potential of this technique could be realised. 

        

    Since 1985, 540 accoustic neuromas were treated with mean age 51, 48% males, 21% (116) were bilateral tumours. The median diameter was 6-57mm. 36% had at atleast one previous resectional surgery. A large proportional had neurological deficit particularly with those who had surgical intervention. Even since 1995, only 20% have normal facial nerve function and 13% had none. Seventy-two cases of previously operated cases had complete deafness.

        

    In 1980, when 25Gy dose was given, facial weakness in 85% and hearing preservation was poor. With reduction of dose to 13-15Gy, radiological tumour control remained around 88% with minimum follow-up of 5 years. Useful hearing was preserved in 76% and facial weakness only in 5.2%. These results compare well with larger surgical series.

        

    Radiosurgical failures are not declared for at least 3 yrs and no surgery should be undertaken on this basis.

        

    The risks and difficulty of surgery after radiosurgery is exaggerated.

        

    A warning by nonpractising radiosurgeons is given to patietns of possibility of malignant change in later years. Very rarely seen. To date about 15000 acoustic neuromas are treated and by telephone survey, only 5 cases of sarcomatous change were confirmed after radiosurgery. Nevertheless, the alertness is necessary.

        

    Which cases should be referred to radiosurgery? Probably the answer is which should not be?

        

    Lesions beyond 3.5cm that produce larger mass effect may need surgical decompression. Tumours incidentally found may be monitored radiologically and audiometrically.

        

    Those above 65 years of age, the medically infirm and those who can’t afford even a low risk of surgical mortality will be more and more considered for radiosurgery.

        

    There is a demand for noninvasive methods of treatment with less disruption to their life. Those who are well informed by internet and those who are in medicolegal climate should be informed of availability of radiosurgery of these tumours.

         

  • Dr. Paul A Fagan, St. Vincent’s Hospital, Sydney, Australia

    How does the outcome of radiotherapy compare with microsurgery for vestibular schwannomas?

    ENT News, Nov./Dec.2000. vol.9(5), p.20

        

    The article discusses pros and cons of both treatment but tilts more in tumour of surgery.

          

    In summary, the author states surgery for acoustic neuroma is a proven, safe and effective treatment with reproducible results. In particular, the long-term safety of this treatment is well documented. Radiotherapy, on the other hand, does not achieve a cure, the early results are little different to the natural history of the disease and serious long-term complications can occur.

        

  • L Dade Lunsford, Ajay Niranjan, (Pittsburg, Philadelphia)

    What are the results and rationale of stereotactic radiotherapy in the management of vestibular schwannomas?

    ENT News, Vol.9(5), Nov./Dec.2000. P.23

        

    For acoustic neuromas, the surgical alternatives are microsurgery and gamma knife.

      

    Today, good imaging technique achievers have very early diagnosis with minimal symptoms. The goals of management have shifted from tumour removal to preservation of neurological function viz. facial nerve function and hearing preservation.

       

    The goals of radiosurgery are to inactivate the tumour, as against physical removal by microsurgery. The gradual tumour reduction in size is noted over the next two to seven years period. The aim is to prevent further growth, while preserving 7th and 8th nerve function and other neurological and employment status. 

       

    At the University of Pittsburgh, 622 patients have undergone gamma knife radiosurgery over a period of 13 years.

       

    Currently, 13Gy to the tumour margin in a single session is utilized. Usually within 6-18 hours patient is discharged. All patients are followed up with MRI and audiometric studies at 6-months, 1,2,4 and 8 years.

       

    Analysis of 5-10 year outcome of 162 unilateral tumours treated with radiosurgery between 1987 and 1992, a 98% tumour control rate has been achieved. Only 2% of patients required tumour resection. No additional difficulties were encountered in resection procedure.

       

    No patient with an intracanalicular tumour developed new facial or trigeminal neuropathies, 21 of 487 patients (4.3%) had improvement in hearing.

        

    With all patients, the concept of tumour growth control versus tumour removal should be discussed. All options should be put forward. According to him by 2001, many patients with newly diagnosed acoustic tumours should undergo gamma knife radiosurgery as the management option of choice.

       

  • Som PM, Curtin HD, Mancuso AA

    Imaging of the Neck 

    ORL 2000; 62: 186-198

         

    This article relates to the use of C-T scanning in staging of neck in details. A full written classification is given in the text together with diagnosis explaining each of the levels. It is very clear and consistent set of guidelines to help stage the neck on radiological grounds
    – CJW.

        

  • Kau R J, Alexiou C, Stimmer H, Arnold W.

    Investigations for neck nodes

    ORL, 2000; 62: 199-203

       

    This well-written article from Germany provides an overview of the current methods used in status of neck nodes in head and neck malignancies. It compares CT, MRI, ultrasound (US), US guided FNAC, colour doppler US and PET with clinical staging.

        

    The least accurate method of detecting lymph node, though the cheapest method of palpation gives 69.7% accuracy. Ultrasound with its limitation of 72.7%, and US guided FNAC 89%.¸CT has 84.9%, MRI 85%. PET scanning most accurate at 90.5% but is not easily available. Colour doppler studies –show reactive nodes have increased hilar blood flow, while metastatic nodes have peripheral blood flow.

        

    The advantage of US guided FNAC is that it gives histological diagnosis and staging. However, its invasive procedure is to be kept in mind.

        

  • Fertilo A, Som PM, Rinaldo A, Mondin V

    Classification of neck dissection

    ORL – 2000; 62: 212-216

        

    Many terms are used in various neck dissection procedures but to describe accurately what procedure has been done is still confusing.

        

    The most commonly accepted classifications designed by Fertilo in 1998. This divides into (1) comprehensive neck dissection (2) selective neck dissection and (3) extended neck dissection.

       

    1. Comprehensive neck dissection
    – (including radical or modified radical) involves dissection of I-V level.

    2. Selective neck dissection

         In this one or more lymph node levels are left in situ.

    3. Extended neck dissection – it implies removal of all I-V level nodes and additional lymph nodes or structures, which are
    not     
    removed in radical neck. Additional structures include accessory nerve, jugular vein, or sternocleidomastoid muscle.

        

    The authors suggest the staging of the neck by P M Som to be methodology and then described the surgical procedures in the above manner i.e. level of lymph nodes and additional structures removed or preserved. This is simple method to record and compare.

        

  • Fertilo A, Silver CE, Rinaldo A, Smith RV 

    Surgical options for the neck

    ORL 2000: 62: 217-225.

         

    This article summarises the surgical options for both NO and node positive necks. It also discusses the adjuvant treatment of radiotherapy or chemotherapy.

        

    (A) In clinical and radiological negative neck
    – selective lateral neck dissection with levels II to IV or VI as necessary with or without preservation of 11th, Jugular vein or sternocleidomastoid.

         

    (B) In the necks – treatment varies on N stage.

         (a) High N stage neck
    – Radical neck dissection including VI and VII where necessary.

        

         (b) However, N stage neck
    – more selective neck dissections after levels I to V including VI or VII.

        

    Postoperative adjuvant therapy are best reserved for extracapsular spread. Authors prefer primary surgery as it allows accurate p-staging with obvious prognostic implications. CJW.

        

  • Pediatric

    Coppit III G L, Perkins JA, Manning SC

    Hairy polyps ?

    International Journal of Pediatric Otorhinolaryngology 2000: 52: 3: 219-227.

         

    The authors report four cases of nasopharyngeal dermoids and teratomas along with review of literature which include 40 cases. These lesions colloquially are called hairy polyps. Clinically two distinction described by Arnold’s classification, which basically divides the lesions into dermoids, teratoids, true teratomas and epignathi. Dermoids comprise lesions containing two germinal layers (ectoderm and mesoderm). The other has 3 germinal layers with progressive degrees of differentiation.

        

    The major problem is that the teratomas are much more likely to be associated with polyhydramios and other congenital anomalies and possibly require intensive airway management – DS.

        

  • Rudolph J Schrot, and J Paul Muizelaar

    Mannitol in Acute Traumatic Brain Injury

    Lancet Vol.359, May 11, 2002, pg.1633-34

      

    Randomised controlled trials are still sorely needed in neurosurgery, and a recent publication by Julio Cruz and colleagues describing the dose-response effect of preoperative mannitol on acute subdural haematomas is an important contribution to the evidence base in traumatic brain injury.

      

    There are only three other randomised controlled clinical trials evaluating mannitol use in head injury. Smith and colleagues compared mannitol therapy guided by intracranial pressure with that given empirically. Mannitol was compared with pentobarbital, Sayre and colleagues compared a bolus dose of mannitol given before hospital admission with a dose of saline.

      

    This third study may have indicated a slight improvement in mortality with mannitol therapy, but none of the studies showed much difference between treatments. Moreover, no previous study addressed the questions that most often plague neurointensivists – for example, whether mannitol be given as a bolus or a continuous infusion, and whether there is an optimum dose.

      

    Mechanistic studies subsequently showed that mannitol decreases blood viscosity and reduces the diameter of pial arterioles in a manner similar to the vascoconstriction produced by hyperventilation. Although osmotic tissue dehydration may still play some role, mannitol works primarily through its immediate rheological effect, diluting the blood and increasing the deformability of erythrocytes, thereby decreasing blood viscosity.

      

    Cerebral blood flow is augmented by the decreased viscosity and by the favourable effect of the increased intravascular volume on the mean arterial pressure. The sudden increase in cerebral blood flow causes autoregulatory vasoconstriction of cerebral arterioles, decreasing the intracerebral blood volume lowering the intracranial pressure.

      

    Moreover, even when mannitol does not reduce intracranial pressure much, it still increases cerebral blood flow by up to 30%, which may have important clinical effects.

      

    The real value in the report by Cruz and colleagues lies in clinically validating what has always been suspected – that mannitol really helps, especially in the first few hours after the haemorrhage when the risk of secondary ischaemic damage is greatest.

        

 



 

 

Speciality Spotlight

 

      

  • JP Leonetti, T Origitano, et al (Loyola Univ, Maywood, III)
    Intracranial Complications of Temporal Bone Osteoradionecrosis.
    Am J Otol 18:223-229, 1997
        
    Osteoradionecrosis of the temporal bone may follow radiation to the brain, parotid gland, nasopharynx, or superior cervical area.  Life-threatening intracranial complications may follow.
        
    In 4 patients studied, complications observed were multiple brain abscesses, aneurysm of the internal carotid artery; a cholesteatoma of the external auditory canal with extensive destruction of the mastoid bone leading to thrombosis and meningitis of the sigmoid sinus; meningitis with a small epidural abscess over the middle fossa dura; and prolonged infection of the ear canal, middle ear, and mastoid resulting in fatal otitic meningitis. The 3 patients who underwent surgery (mastoid) survived requiring careful and regular follow-up.
        

  • PA Fagan, JP Sheehy, et al (St. Vincent’s Hosp, Sydney, Australia)
    The Cerebellopontine Angle: Does the Translabyrinthine Approach Give Adequate Access?
    Laryngoscope 108: 679-682, 1998
        
    It was previously believed that the translabyrinthine approach provided inadequate access to the cerebellopontine angle. The authors after analyzing 33 patients undergoing translabyrinthine surgery and 13 undergoing the posterior fossa approach have concluded that the translabyrinthine approach enables superior visualization through a wider angle of surgical access with minimal cerebellar retraction. 
        

  • HM Dunniway, DB Welling (Ohio State Univ, Columbus)
    Intracranial Tumors Mimicking Benign Paroxysmal Positional Vertigo.
    Otolaryngol Head Neck Surg, 118:429-436, 1998.
        
    Benign positional vertigo may not always be benign, as indicated in this study where intracranial tumors were identified in five patients who presented as “benign paroxysmal vertigo.”
        
    When patients of “benign paroxysmal vertigo” do not improve after particle repositioning manoeuver, further assessment is needed to rule out intracranial new growths.
         

  • RC O’Reilly, SB Kapadia,  D.B. Kamerer (Univ of Pittsburgh, Pa)
    Primary Extracranial Meningioma of the Temporal Bone.
    Otolaryngol Head Neck Surg  118:690-694, 1998.
        
    Though meningiomas typically occur intracranially, they may rarely arise de novo in the temporal bone.  Because of the invasive nature of this tumor, surgical resection is difficult, and postoperative surveillance is necessary .

  • Michael L, Rosenberg, MD, and Martin Gizzi, MD, PhD From the New Jersey Neuroscience Institute, Edison, New Jersy,
    Neuro-Otologic History
    Otolaryngologic Clinics of North America, Volume 33, No.3 June 2000, Pg. 471- 482
       
    A complete description of the patient’s symptoms is crucial for the diagnosis.
     
    Definition of Terms : Vertigo, Visual Disorientation, Lightheadedness, and Imbalance
      
    1.    Vertigo is the illusory sensation of motion.True vertigo is caused by pathology in the peripheral end organ, the vestibular   nerve, the vestibular nuclei, the cerebellum, and the pathways that connect them in the brainstem and, rarely, the cortex.
     
    2.    Visual disorientation may mimic acute ataxia. A second, but related, from of visual disorientation is the disruption of depth perception associated with new onset strabismus.
     
    3.    Lightheadedness term should be reserved for symptoms similar to those preceding syncope. Lightheadedness is presumably caused by cerebral hypoxia, and may be cardiac or vasovagal in origin.
     
    4.    Imbalance, is the inability to maintain the center of gravity and affected patients note unsteadiness, stumbling, and falling.
      
    Precipitating Factors
     
    Vertigo brought on by lying supine and turning to one side is typical of benign paroxysmal positional vertigo [BPPV] . Lightheadedness brought on by getting up quickly from a lying or sitting position.
     
    Patients with BPPV also may have brief vertigo and nystagmus on sitting up quickly.
     
    Patients with cerebellar disease may remain symptomatic as long as they remain in that position.
     
    Patients with motor balance disorders, related to cerebellar degeneration or to parkinsonism, usually report symptoms only when walking.
     
    DURATION OF SYMPTOMS
     
    Fleeting
     
    Vertigo lasting only a few seconds is most likely related to a fixed vestibular lesion, such as follows vestibular neuronitis or the late stages of Meniere’s disease.
     
    Seconds
      
    Symptoms lasting from 5 to 90 seconds are typical of BPPV, but most last less than 15 seconds.
        
    Minutes
     
    Attacks of vertigo lasting 2 to 20 minutes are consistent with a transient ischemic attack [TIA] affecting the posterior circulation.
     
    Characteristically, posterior circulation TIAs are accompanied by diplopia, visual field defects, ataxia, hemisensory loss, or hemiparesis.
     
    Hours
     
    The major attacks of Meniere’s disease last 20 minutes to 24 hours, but most commonly last 4 to 8 hours.
     
    Migraine may present as vertigo lasting minutes or hours.
     
    Acoustic neuroma is an uncommon cause of vertigo as it is a chronic condition and damage to vestibular fibers is compensated for quickly.
     
    Days
     
    An isolated attack of vertigo lasting more than 24 hours is strongly suggestive of vestibular neuronitis.
     
    Vertigo usually lasts 2 to 3 days but occasionally up to a week.
     
    Vertigo lasting more than 3 days is often seen in acute central nervous system disease.
     
    A continuous sensation of vertigo lasting longer than 1 or 2 weeks without daily variation is probably a psychogenic phenomenon.
     
    Vertigo of vestibular origin probably cannot persist on a physiologic basis for more than 2 weeks.
     
    Associated Otologic Complaints
     
    Otologic complaints, such as hearing loss, tinnitus, or ear fullness, provide important clues as to the location of a lesion.
     
    Episodic tinnitus with fluctuating hearing loss may make the diagnosis of Meniere’s disease.
     
    Classically, patients with Meniere’s disease experience increased tinnitus and worsening of hearing loss during the time of vertigo attack.
     
    Pain associated with vestibular symptoms should raise suspicion of middle ear disease; however, it also may be associated with invasive disease of the temporal bone and with meningeal irritation.
     
    Visual function
     
    All sensory information [ other than taste and smell] can be used to give information about position and velocity relative to the surround.
     
    Vision, in particular, is used to stabilize the world.  It can suppress strongly any nystagmus and the sense of motion generated by the vestibular system.
     
    In the dark the visual system can no longer provide the stabilizing information.
     
    A normal person has no difficulty relying on vestibular information in such situations, but a patient with a vestibular imbalance may report that the world is moving.
        

        

  • JA  Gastel, MA Palumbo, MJ Hulstyn, et al (Brown Univ, Providence, Rl)
    Emergency Removal of Football Equipment: A Cadaveric Cervical Spine Injury Model.
    Ann Emerg Med 32: 411-417, 1998.
       
    Purpose: The proper early management of suspected cervical spine injuries in football players is critical. EMT’s are trained to remove the helmet to avoid hyperflexion of the neck but sports medicine experts recommend against this practice. A cadaver study was conducted to analyse the effects of a football helmet or shoulder pads on alignment of the unstable cervical spine.
         
    Methods: The study included 8 cadavers of average age 73 years. A simulated bilateral facet dislocation was created at C5-C6 motion segment. Lateral x-rays were taken before and after injury with cadaver wearing (1) no equipment (2) a helmet only (3) shoulder pads only and (4) a helmet and shoulder pads. The effect of the alignment of the cervical spine was studied.
         
    Results: Lordosis was decreased by 9.6 degrees with helmet only and increased 13.6 degrees with shoulder pads only.
         
    After destabilisation of the cervical spine, C5-C6 forward angulation was increased by 16.5 degrees with helmet only and the posterior disc space height was increased by 3.8mm and dorsal element distraction by 8.3 mm. In the other 3 indications there were no significant differences.
        
    Conclusions: The results suggest that the helmet and shoulder pads should be left in place until the patient reaches a hospital unless CPR is required.
        

  • WF Donaldson III, WC Lauerman, B Heil, et al (Univ of Pittsburgh, Pa)
    Helmet and Shoulder Pad Removal From a Player With Suspected Cervical Spine Injury: A Cadaveric Model.
    Spine 23: 1729-1733, 1998.
         
    Objective: Cervical spine injuries can result in quadriplegia. The problem of removing the helmet and shoulder pads of an injured football player has been debated. A cadaver model was used to study how much motion occurs with 2 types of injuries when a helmet and shoulder pads are removed.
         
    Methods: Transoral osteotomy at waist of odontoid process was done to render C1-C2 unstable in 3 cadavers and in another 3 cadavers, the interspinous ligaments, the facet capsules, posterior longitudinal ligaments and posterior one third of the disc were sectioned at C5-C6.  Under fluoroscopic visualization, 4 people removed the helmets by first removing the facemask, then the chinstrap and then the ear-pieces. The shoulder pads were then removed. Maximum displacements were recorded and analysed.
         
    Results: Instability at C2 resulted in a change in angulation of 5.47 degrees distraction of 2.98 mm and a change in space available for the cord by 3.91 mm when the helmet was removed. With removal of shoulder pads, the change in angulation was 2.9 degrees distraction 1.76mm and the change in the space available for the cord 2.64 mm.
        
    Conclusions: A significant amount of movement can occur in an unstable cervical spine when the helmet and shoulder pads are removed. Therefore, it would be unwise to try to remove the helmet and shoulder pads before transportation to hospital.
         

  • MJ Wetzler, T Akpata, W Laughlin, et al (American Orthopaedic Rugby Football Assoc, Washington Crossing, Pa; South Jersey Orthopedic Associates, Voorhees, NJ: Rugby Magazine, New York; et al )
    Occurrence of Cervical Spine Injuries During the Rugby Scrum
    Am J Sports Med 26: 177-180, 1998.
         
    Objective: The scrum is responsible for 60% of cervical spine injuries in rugby.  The cause and reduction of cervical spine injuries during the rugby scrum were studied retrospectively.
      
    Methods: Data on 62 injured players was compiled from oral and written reports and from medical records.
        
    Results:  Between 1970 and 1996, 36 (58%) players sustaining a cervical spine injury were injured during a scrum with 23(64%) occurring during the engagement and 13 (36%) during the collapse of the scrum.
        
    Players injured during the engagement were hookers (22%), props (11%) and a second row player (3%). There were 21 (58%) senior level players and 15(42%) junior level players. Nine (25%) occurred as a result of a mismatch inexperience.
        
    Conclusion: Cervical spine injuries to rugby players occur more frequently during the engagement phase of the scrum, to hookers, and to lower level players.

  • Joel A, Goebel, MD, FACS From the Department of Otolaryngology,Washington University School of Medicine, St. Louis, Missouri
    Management Options for Acute Versus Chronic Vertigo
    Volume 33, No.33, June 2000, Pg. 483-493
     
    Vertigo is one of the most frequent and disturbing sensations that the practicing otolaryngologist is called upon to treat.
     
    Vertigo is defined as a false illusion of motion with a distinct rotational component.
     
    Recurrent attacks of vertigo are addressed as chronic vertigo.
     
    Rotational chair tests explore the VOR and visual-vestibular interaction.
     
    CPD is used in cases of postural instability to document patterns of sensory organization and motor control during various visual and support-surface challenges.
     
    THERAPEUTIC OPTIONS
     
    Medical Therapy
     
    Most medications for acute attacks of vertigo are centrally acting suppressants for nausea and vomiting.
     
    For acute spells, diazepam 2 to 5 mg three times daily works well. Meclizine 25 mg three times daily and promethazine 25 to 50 mg every 8 hours is another useful combination. Tapered steroid regimen is useful in early vestibular neuritis. They are not to be used chronically or for prophylaxis against subsequent attacks.
     
    Surgical Therapy
     
     
    Candidates for surgical therapy represent a small fraction [< 5%] of all dizzy patients.
     
    Surgical procedures for vertigo can be described by two characteristics - ablative/non-ablative and hearing preserving/hearing destroyed.
     
    Ablative procedures include transmastoid labyrinthectomy and vestibular nerve section.
     
    In many centers, transtympanic gentamicin therapy has dramatically reduced the necessity for surgical ablation.
     
    Non-ablative procedures include endolymphatic sac decompression, endolymphatic sac shunt, and posterior canal occlusion.
        

         

  • Alexiadou-Rudolf C, Ernestus R-1, Nanassis K, et al [Univ of Thessaloniki, Greece]
    Acute Nontraumatic Spinal Epidural Hematomas : An Important Differential Diagnosis in Spinal Emergencies
    Spine 23: 1810-1813, 1998
       
    Fewer than 1% of spinal epidural space-occupying lesions are spontaneous spinal epidural hematomas [SSEHs], a rare spinal emergency that can be difficult to recognize.
       
    Good outcomes require an accurate diagnosis and prompt surgical decompression.
       
    Most cases occur in the lumbar region and dorsal to the spinal cord.
       
    The typical history is acute, nontraumatic onset of local pain, with signs of spinal cord compression occurring within hours.
       
    The differential diagnosis includes spinal abscess, tumor, ischemia, transverse myelitis, and acute vertebral disk disease, but the time spent on diagnostic tests may reduce the chance of a good outcome.
       
    Patients with SSEH present with rapidly progressive sensorimotor paralysis or cauda equina syndrome.
       
    Good postoperative function can be expected only if the patient is operated on within 12 hours after onset of symptoms.
       
    MRI is the diagnostic method of choice and shows signal behavior identical to that of intracerebral hematoma. Spinal MRI should be performed as quickly as possible to avoid diagnostic delays.
        

  • MS Abdou, AR Cohen (Case Western Reserve Univ, Cleveland, Ohio) : Endoscopic Treatment of colloid Cysts of the third Ventricle: Technical Note and Review of the Literature.
      J Neurosurg 89:1062-1068, 1998.
         
    In some patients, colloid cysts may obstruct the foramina of Monro, resulting in hydrocephalus, intracranial hypertension and neurologic dysfunction. A technique for endoscopic management of colloid cysts and its outcomes were reported.
        
    Endoscopic surgery allows wide fenestration of the capsule and aspiration of the cyst contents under direct vision, with minimal disruption of the cortex and other normal brain structures. The endoscope is the ideal instrument for exploring fluid-filled cavities. The intraventricular location of colloid cysts makes these lesions especially accessible.
         

  • T Menovsky, JA Grotenhuis, J de Vries, et al (Univ Hosp of Nijmegen, The Netherlands) 
    Endoscope-assisted Supraorbital Craniotomy for Lesions of the Interpeduncular Fossa.
      Neurosurgery 44: 106-112, 1999.
        
    The supraorbital approach is accepted for lesions in the anterior fossa, the sellar region and the anterior part of the circle of Willis. However, for lesions in the interpeduncular fossa, this approach has not been widely used. The use of an endoscope allows a bright and excellent view into the interpeduncular fossa, necessary for a minimally invasive supraorbital approach.
        
    With this technique, the surgical route is nearly perpendicular, the amount of dissection and brain retraction minimized, and the surgical incision is small
         

  • EJ Kosnik (Ohio State Univ, Columbus; Children’s Hosp, Columbus, Ohio) :
    Use of Ligamentum Nuchae Graft for Dural Closure in Posterior Fossa Surgery : Technical Note.
      J Neurosurg 89:155-156, 1998. 
         
    In posterior fossa surgery, watertight dural closure helps to support the cerebellum and to prevent contamination of the CSF. 
        
    Excellent results were achieved by the authors, using ligamentum nuchae graft for watertight dural closure in patients undergoing posterior fossa surgery. There have been no problems with CSF leakage or pseudomeningoceles. 
         
    The ligamentum nuchae provides a safe, effective and readily available material for closure of posterior fossa dural defects.
           

  • DA Hollander, NJ Volpe, et al (Univ of Pennysylvania School of Medicine; Albert Einstein Hospital, Philadelphia)
    Use of a portable head mounted perimetry system to assess bedside visual fields.
    BJO 2000; 84: 1185-1190
      
    The authors describe a head mounted, AUTOMATED perimetry system, which is portable and convenient for examining neurosurgical patients at their bedside in the perioperative period.
      
    The method offers standardised, quantifiable testing with graphic results for follow-up examinations. 
       
    The device showed equal sensitivity to methods of confrontation field testing, in detecting field defects.
       

  • D.N. Parmar, A.Sofat, R. Bowman, et al (Department of Neurosciences, King’s College Hospital, London)
    Visual prognostic value of the pattern electroretinogram in chiasmal compression.
    Br.J.Ophthalmol 2000: 84: 1024-1026.
      
    The visual loss caused by chiasmal (optic) compression by pituitary tumours may be transient or permanent. This is possibly related to the extent of irreversible retrograde degeneration of the retinal ganglion cells.
      
    The pattern electroretinogram (PERG) N95 component is believed to rise in relation to retinal ganglion cell function and may be a potential prognostic indicator for visual function following decompressive surgery.
       
    Records of 72 eyes from 36 patients were retrospectively analysed. It was concluded that the PERG is a useful visual prognostic indicator in the preoperative assessment of chiasmal compression.
        

  • P. Chang, Los Angeles, USA.
    Controversies in Vestibular Schwannoma Treatment: Surgery versus Irradiation.
    ENT News, 9(5), Nov./Dec.2000, p.14-15
        

    Cropping of these controversies has been because of irradiation as an alternative to surgery. Microsurgery is the present day choice for vestibular schwannoma.
         
    The following questions arise in the critical minds of patients:
    a) What is the expected morbidity of surgery?
    b) Is hearing preservation possible?
    c) Can benign tumour be irradiated without any long-term side effects?
    d) How effective radiation is?
    e) Are the results competitive to that of surgery. Will all be judged in justifying the alternative treatment of Vestibular Schwannoma?
         
    Tumour: 
    Vestibular schwannoma tumours arise from neural sheaths and are benign. Their situation in internal auditory canal and cerebellopontine angle, make them dangerous by position. The tumour consists of nothing but proliferating Schwann cells, which is very slow viz. 1 to 2 mm per year. Majority grows producing progressive hearing loss. This growth however, exceptionally can be unpredictable. That is why in fit patient, intervention is required. Technological advances in early precise diagnosis by imaging techniques and advances in management have proved the surgical outcomes much favourable.
         
    However, technological advances in radiotherapy have also offered an alternative treatment.
         
    Surgical Background:
    It has come a long way from removal of tumour by finger, by Balance in London in 1894 to perfection of precise removal by translabyrinthine, retrosigmoid and middle fossa approaches derived by Dr. William House in 1964, almost without mortality and minimal of morbidity. Today there is likelihood of complete removal with zero mortality rate, near normal facial nerve function in 95% and less than 0.3% recurrence rate and 70% rate of preservation of hearing in selected patient makes the treatment by surgical excision treatment of choice.
          
    The negative points are that it is intracranial procedure with its attendant risks of C.S.F leak, meningitis and intracranial bleed. It incurs cost and 4-5 days of hospitalization.
         
    Today the treatment by radiation may be opted to (a) Medically unfit patients (b) Recurrent tumours (c) Elderly patients (d) Who refuse surgery. The use of radiotherapy as primary mode of treatment of vestibular schwannoma has also been promoted.
         
    Background of Radiotherapy
    Lars Leksell (1971) at Sweden (Karolinska Institute in Stockholm) first reported gamma radiation ports administered stereotactically during a single sitting to arrest the tumour growth.
         
    The principle is to target the lesion, minimising, the radiation dose to surrounding neural tissues. The term “stereotactic radiosurgery” was coined and particular technique used was called the ‘gamma knife’.
         
    The treatment evolved in last decades. The radiation dosage of 25Gy has been reduced optimally to 13Gy delivered by Linear accelerator and is now fractionate. This has resulted into improvement in tumour control and preservation of normal neural tissue.
         
    The Controversy
    – Because of close relations of tumour capsule to 7th and 8th nerve, it is impossible to avoid radiation to these nerves.
         
    – The effects of radiation are cell deaths and delayed vasculitis. Vasculitis is not observed because of sparse blood supply as against seen in glomus.
        
    – Subsequent surgical intervention, if required in these irradiated tumour, lead to hazzardous dissection resulting in poor hearing and facial nerve function.
        
    So the alternative treatment is reserved for those patients who are unfit or unwilling to undergo microsurgical removal of tumour.
        

  • Andras A Kemeny, Royal Hallamshire Hospital, Sheffield, England
    What is the role of radiosurgery in Vestibular Schwannoma treatment?
    ENT News, Nov/Dec.2000, vol.9(5), p.19
        
    It is a surgical technique, the concentrated radiation is achieved by crossfiring 201 fine gamma ray beams focused into a single point. Initially with poor imaging and slow computers, this was difficult to achieve. But with the introduction of high resolution, volume acquisition MR imaging and powerful 3D computational software the true potential of this technique could be realised. 
        
    Since 1985, 540 accoustic neuromas were treated with mean age 51, 48% males, 21% (116) were bilateral tumours. The median diameter was 6-57mm. 36% had at atleast one previous resectional surgery. A large proportional had neurological deficit particularly with those who had surgical intervention. Even since 1995, only 20% have normal facial nerve function and 13% had none. Seventy-two cases of previously operated cases had complete deafness.
        
    In 1980, when 25Gy dose was given, facial weakness in 85% and hearing preservation was poor. With reduction of dose to 13-15Gy, radiological tumour control remained around 88% with minimum follow-up of 5 years. Useful hearing was preserved in 76% and facial weakness only in 5.2%. These results compare well with larger surgical series.
        
    Radiosurgical failures are not declared for at least 3 yrs and no surgery should be undertaken on this basis.
        
    The risks and difficulty of surgery after radiosurgery is exaggerated.
        
    A warning by nonpractising radiosurgeons is given to patietns of possibility of malignant change in later years. Very rarely seen. To date about 15000 acoustic neuromas are treated and by telephone survey, only 5 cases of sarcomatous change were confirmed after radiosurgery. Nevertheless, the alertness is necessary.
        
    Which cases should be referred to radiosurgery? Probably the answer is which should not be?
        
    Lesions beyond 3.5cm that produce larger mass effect may need surgical decompression. Tumours incidentally found may be monitored radiologically and audiometrically.
        
    Those above 65 years of age, the medically infirm and those who can’t afford even a low risk of surgical mortality will be more and more considered for radiosurgery.
        
    There is a demand for noninvasive methods of treatment with less disruption to their life. Those who are well informed by internet and those who are in medicolegal climate should be informed of availability of radiosurgery of these tumours.
         

  • Dr. Paul A Fagan, St. Vincent’s Hospital, Sydney, Australia
    How does the outcome of radiotherapy compare with microsurgery for vestibular schwannomas?
    ENT News, Nov./Dec.2000. vol.9(5), p.20
        
    The article discusses pros and cons of both treatment but tilts more in tumour of surgery.
          
    In summary, the author states surgery for acoustic neuroma is a proven, safe and effective treatment with reproducible results. In particular, the long-term safety of this treatment is well documented. Radiotherapy, on the other hand, does not achieve a cure, the early results are little different to the natural history of the disease and serious long-term complications can occur.
        

  • L Dade Lunsford, Ajay Niranjan, (Pittsburg, Philadelphia)
    What are the results and rationale of stereotactic radiotherapy in the management of vestibular schwannomas?
    ENT News, Vol.9(5), Nov./Dec.2000. P.23
        
    For acoustic neuromas, the surgical alternatives are microsurgery and gamma knife.
      
    Today, good imaging technique achievers have very early diagnosis with minimal symptoms. The goals of management have shifted from tumour removal to preservation of neurological function viz. facial nerve function and hearing preservation.
       
    The goals of radiosurgery are to inactivate the tumour, as against physical removal by microsurgery. The gradual tumour reduction in size is noted over the next two to seven years period. The aim is to prevent further growth, while preserving 7th and 8th nerve function and other neurological and employment status. 
       
    At the University of Pittsburgh, 622 patients have undergone gamma knife radiosurgery over a period of 13 years.
       
    Currently, 13Gy to the tumour margin in a single session is utilized. Usually within 6-18 hours patient is discharged. All patients are followed up with MRI and audiometric studies at 6-months, 1,2,4 and 8 years.
       
    Analysis of 5-10 year outcome of 162 unilateral tumours treated with radiosurgery between 1987 and 1992, a 98% tumour control rate has been achieved. Only 2% of patients required tumour resection. No additional difficulties were encountered in resection procedure.
       
    No patient with an intracanalicular tumour developed new facial or trigeminal neuropathies, 21 of 487 patients (4.3%) had improvement in hearing.
        
    With all patients, the concept of tumour growth control versus tumour removal should be discussed. All options should be put forward. According to him by 2001, many patients with newly diagnosed acoustic tumours should undergo gamma knife radiosurgery as the management option of choice.
       

  • Som PM, Curtin HD, Mancuso AA
    Imaging of the Neck 
    ORL 2000; 62: 186-198
         
    This article relates to the use of C-T scanning in staging of neck in details. A full written classification is given in the text together with diagnosis explaining each of the levels. It is very clear and consistent set of guidelines to help stage the neck on radiological grounds – CJW.
        

  • Kau R J, Alexiou C, Stimmer H, Arnold W.
    Investigations for neck nodes
    ORL, 2000; 62: 199-203
       
    This well-written article from Germany provides an overview of the current methods used in status of neck nodes in head and neck malignancies. It compares CT, MRI, ultrasound (US), US guided FNAC, colour doppler US and PET with clinical staging.
        
    The least accurate method of detecting lymph node, though the cheapest method of palpation gives 69.7% accuracy. Ultrasound with its limitation of 72.7%, and US guided FNAC 89%.¸CT has 84.9%, MRI 85%. PET scanning most accurate at 90.5% but is not easily available. Colour doppler studies –show reactive nodes have increased hilar blood flow, while metastatic nodes have peripheral blood flow.
        
    The advantage of US guided FNAC is that it gives histological diagnosis and staging. However, its invasive procedure is to be kept in mind.
        

  • Fertilo A, Som PM, Rinaldo A, Mondin V
    Classification of neck dissection
    ORL – 2000; 62: 212-216
        
    Many terms are used in various neck dissection procedures but to describe accurately what procedure has been done is still confusing.
        
    The most commonly accepted classifications designed by Fertilo in 1998. This divides into (1) comprehensive neck dissection (2) selective neck dissection and (3) extended neck dissection.
       
    1. Comprehensive neck dissection – (including radical or modified radical) involves dissection of I-V level.
    2. Selective neck dissection
         In this one or more lymph node levels are left in situ.
    3. Extended neck dissection – it implies removal of all I-V level nodes and additional lymph nodes or structures, which are not      removed in radical neck. Additional structures include accessory nerve, jugular vein, or sternocleidomastoid muscle.
        
    The authors suggest the staging of the neck by P M Som to be methodology and then described the surgical procedures in the above manner i.e. level of lymph nodes and additional structures removed or preserved. This is simple method to record and compare.
        

  • Fertilo A, Silver CE, Rinaldo A, Smith RV 
    Surgical options for the neck
    ORL 2000: 62: 217-225.
         
    This article summarises the surgical options for both NO and node positive necks. It also discusses the adjuvant treatment of radiotherapy or chemotherapy.
        
    (A) In clinical and radiological negative neck – selective lateral neck dissection with levels II to IV or VI as necessary with or without preservation of 11th, Jugular vein or sternocleidomastoid.
         
    (B) In the necks – treatment varies on N stage.
         (a) High N stage neck – Radical neck dissection including VI and VII where necessary.
        
         (b) However, N stage neck – more selective neck dissections after levels I to V including VI or VII.
        
    Postoperative adjuvant therapy are best reserved for extracapsular spread. Authors prefer primary surgery as it allows accurate p-staging with obvious prognostic implications. CJW.
        

  • Pediatric
    Coppit III G L, Perkins JA, Manning SC
    Hairy polyps ?
    International Journal of Pediatric Otorhinolaryngology 2000: 52: 3: 219-227.
         
    The authors report four cases of nasopharyngeal dermoids and teratomas along with review of literature which include 40 cases. These lesions colloquially are called hairy polyps. Clinically two distinction described by Arnold’s classification, which basically divides the lesions into dermoids, teratoids, true teratomas and epignathi. Dermoids comprise lesions containing two germinal layers (ectoderm and mesoderm). The other has 3 germinal layers with progressive degrees of differentiation.
        
    The major problem is that the teratomas are much more likely to be associated with polyhydramios and other congenital anomalies and possibly require intensive airway management – DS.
        

  • Rudolph J Schrot, and J Paul Muizelaar
    Mannitol in Acute Traumatic Brain Injury
    Lancet Vol.359, May 11, 2002, pg.1633-34
      
    Randomised controlled trials are still sorely needed in neurosurgery, and a recent publication by Julio Cruz and colleagues describing the dose-response effect of preoperative mannitol on acute subdural haematomas is an important contribution to the evidence base in traumatic brain injury.
      
    There are only three other randomised controlled clinical trials evaluating mannitol use in head injury. Smith and colleagues compared mannitol therapy guided by intracranial pressure with that given empirically. Mannitol was compared with pentobarbital, Sayre and colleagues compared a bolus dose of mannitol given before hospital admission with a dose of saline.
      
    This third study may have indicated a slight improvement in mortality with mannitol therapy, but none of the studies showed much difference between treatments. Moreover, no previous study addressed the questions that most often plague neurointensivists – for example, whether mannitol be given as a bolus or a continuous infusion, and whether there is an optimum dose.
      
    Mechanistic studies subsequently showed that mannitol decreases blood viscosity and reduces the diameter of pial arterioles in a manner similar to the vascoconstriction produced by hyperventilation. Although osmotic tissue dehydration may still play some role, mannitol works primarily through its immediate rheological effect, diluting the blood and increasing the deformability of erythrocytes, thereby decreasing blood viscosity.
      
    Cerebral blood flow is augmented by the decreased viscosity and by the favourable effect of the increased intravascular volume on the mean arterial pressure. The sudden increase in cerebral blood flow causes autoregulatory vasoconstriction of cerebral arterioles, decreasing the intracerebral blood volume lowering the intracranial pressure.
      
    Moreover, even when mannitol does not reduce intracranial pressure much, it still increases cerebral blood flow by up to 30%, which may have important clinical effects.
      
    The real value in the report by Cruz and colleagues lies in clinically validating what has always been suspected – that mannitol really helps, especially in the first few hours after the haemorrhage when the risk of secondary ischaemic damage is greatest.
        

 

 

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