Acoustic neuroma surgery—Shanghai experience

Hao WuDepartment of Otolaryngology-Head and Neck Surgery

Xinhua Hospital, Shanghai Second Medical University

• McBumey (1891): unsuccessful

• Balance (1894): first successful

Cushing Era

• Surgical mortality: 80%

• Cushing –partial removal

Dandy Era（ 1917–1961）• Total removal: mortality↓(22.1%)

• Atkinson (1949): AICA

• Total facial paralysis

1960

• Mortality rate in California: 43.5%

• Olivecrona (Sweden)： 414 cases– small tumors: 4.5%

– large tumors: 22.5%

– Facial paralysis: 50%

Dr. W. House （ 1961-）

•Middle fossa approach (1961)

•Traslab approach (1962)

Origin

Development in the internal acoustic meatus from the schwann cells of the vestibular ganglion (Sterkers JM et al., Acta Otolaryngol., 1987)

Arachnoid sheet enveloping the tumour during its expansion to the CPA.

Epidemiology• 6 to 8 % of all intracranial tumours• The most frequent (80 to 90%) of the

CPA tumours• Sporadic, and solitary in 95 % of cases• Associated with NF2 in 5 % of cases• Estimated incidence in USA and

Western Europe: 1 for 100,000 individuals per year (Kurlan et al., J neurosurg, 1958 ; Nestor JJ et al., Arch Otlaryngol Head Neck Surg, 1988)

REASON FOR CONSULTATION

Expected symptom: 80.7 %(progressive HL,tinnitus,unsteadiness) Sudden hearing loss: 9.6 %Atypical presentation: 10 %

.

..

Moffat et al., 1998n = 473

MRI diagnosis

Isosignal on T1, and variable aspect en T2 views

Constant gadolinium enhancement

Intratumoral cysts in large neurinomes

No adjascent meningeal enhancement

Enlarged IAM

Extension predominantly posterior to IAM

Differential diagnosis

Other neurinomas in the CPA: 5th, 7th, or caudal cranial nerve neurinomasOther lesions:

Most frequent:MeningiomasCholesteatomas

Rare lesions :lipomas, metastases, hemangiomas, medulloblastomas etc…..

Unilateral or asymetrical audio-vestibular signs :Hearing loss, vestibular syndrome, tinnitus

MRI + GadoliniumMRI + Gadolinium Follow-upAudio-vestibular work-up

In 6 months

Neurotological examinationAudiometry+ABR+VNG

Age

< 60 years > 60 years

Abnormality Normal ABR and VNG

Decisionnal factors

1. Tumor volume

2. Age

3. Hearing function

Therapeutic options

Varaiable tumor growth

According to age and tumor size < 1,5 cm

MRI in 6 months and then once a year

Gamma-knife, LINACVolume stabilisationHearing loss and facial paresisUnder evaluation

• Conservative managament

• Surgery

• Radiotherapy

Goals of the surgery

1- Minimal vital and neurological risks

2- Total removal

3- Facial function preservation

4- Hearing preservation

Approaches

Retrosigmoid (RS)

Translabyrinthine (TL)

Middle cranial fossa (MCF)

Acoustic Neuromas

Intracanalar or CPA < 20 mm

> 70 years:Conservativemanagement

< 70 years:Surgery

Poor general condition:Irradiation

CPA> 20 mm

Translabyrinthine or transotictranslabyrinthineMCFretrosigmoid

Hearing

Serviceable Unserviceable

II < 15 mmIII : 15-30 mm

IV > 30 mm

I

• 1999.1-2004.3: 100 VS operated on • Mean age: 49 years (range: 20-79)• Sex ratio: 0.8• Tumor stages :

– Stage 1: 3 %

– Stage 2: 11 %

– Stage 3 : 71 %

– Stage 4 : 15 %

Population

Approaches

•Translabyrinthine : 77 %

•Transotic: 6 %

•Retrosigmoid: 12 %

•Middle cranial fossa: 5 %

17% attempt to hearing preservation

ABRIntraoperative monitoring

Direct cochlear nerve potential

Resection quality

Complete removal in 98 cases Subtotal removal in 1 cases (1 %)

In cases with subtotal removal :1 MRI images demonstrate to be stable (1 %)1 case surgically revised (1 %)

Postoperative facial function in translabyrinthine or transotic

approach

Stages Cases 　　　　 Facial function

　 1　　 2　　 3　　 4　　 5　　 6

总计 83 31 15 13 12 8 4

Hearing preservation

Hearing preservation attempts by middle cranial fossa or retrosigmoid approach (n=17):

Class D: 40 %

Class A: 12 %

Class C: 24 %

Class B: 24 %

Class A+B: 36%

Complications

• CSF leaks: 6%(all in first 39 cases)

Neurological: 3%

Infectious: 1 %

Miscellaneous: 3 %

Translabyrinthine approach

Translabyrinthine removal of VS after radiosurgery

• 5 cases；• Difficult in facial nerve dissection；• Results： total removal in all cases

facial function: grade II in 1 case

grade III in 2 cases

grade IV in 2 cases

grade VI in 1 case

Transotic removal of VS with chronic middle ear infection

• 3 cases；• Results： total removal in all cases

facial function: all with gradeI-II

no postoperative infection

Fallopian bridge technique

Middle fossa approach

Retrosigmoid-IAM approach

Facial nerve repair after interruption

• end-to-ent anastomosis

• Reroute technique

• Bridge technique

• Facial-hypolingual ana.

NF2 and Auditory Brainstem Implant

Hearing rehabilitation in acoustic neuroma surgery

NF2 DIAGNOSIS

• Bilateral vestibular schwannoma (VS)

• NF2 familial history

and

- unilateral VS

- or 2 among : meningioma, glioma, neurofibroma,schwannoma,subcapsular lens opacity

NF2

• NF2 gene on chromosome 22 (1993)

• Tumor suppressor gene

Auditory pathway

Me dia l g e nic ula te bo dy

Infe rio r c o llic ulus

La te ra l le mnisc us

Supe rio r & a c c e sso ry o live a re a

Do rsa l c o c hle a r nuc le usVe ntra l c o c hle a r nuc le us

(Ada pte d fro m "Ne uro to lo g y",Ja c kle r a nd Bra c kma nn)

Co c hle a r

Audito ry c o rte x

VIIIth ne rve

Co c hle a rImpla nt

Audito ryBra inste m

Impla nt

Nucleus 21 Channel Auditory Brainstem Implant

CI22M receiver-stimulator

Monopolarreference electrode

(plate)

Microcoiled electrodewires

Electrode array(21 platinum disks0.7mm diameter)

T-shapedDacronmesh

Removeablemagnet

Bone anchored hearing aide (BAHA)

• Single sided deafness;• FDA approval;

Conclusions 1• In spite of modern image techniques, large VS acounts for most diagnosed cases in China.

•The translabyrinthine app. could be used in even largest VS with minival invasion.

Conclusions 2• The facial function is aceptable in most patients.•The hearing preservation result should still be improved.•Hearing rehabilitation techniques are available after tumor removal.

Thanks