1. Acoustic neuroma surgery—Shanghai experience
Hao Wu
Department of Otolaryngology-Head and Neck Surgery
Xinhua Hospital, Shanghai Second Medical University

2. McBumey (1891): unsuccessful
Balance (1894): first successful

3. Cushing Era
Surgical mortality: 80%
Cushing –partial removal

4. Dandy Era（1917–1961） Total removal: mortality↓(22.1%)
Atkinson (1949): AICA
Total facial paralysis

5. 1960 Mortality rate in California: 43.5% Olivecrona (Sweden)：414 cases
small tumors: 4.5%
large tumors: 22.5%
Facial paralysis: 50%

6. Dr. W. House （1961-） Middle fossa approach (1961)
Traslab approach (1962)

7. 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.

8. 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)

9. REASON FOR CONSULTATION
Moffat et al., 1998
n = 473 .
Expected symptom: %
(progressive HL,tinnitus,unsteadiness)
Sudden hearing loss: 9.6 %
Atypical presentation: 10 % . .

10. 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

11. Differential diagnosis
Other neurinomas in the CPA: 5th, 7th, or caudal cranial nerve neurinomas
Other lesions:
Most frequent:
Meningiomas
Cholesteatomas
Rare lesions :lipomas, metastases, hemangiomas, medulloblastomas etc…..

12. Unilateral or asymetrical audio-vestibular signs :
Hearing loss, vestibular syndrome, tinnitus
Neurotological examination
Audiometry+ABR+VNG
Normal ABR and VNG
Abnormality
Age
< 60 years
> 60 years
MRI + Gadolinium
MRI + Gadolinium
Follow-up
Audio-vestibular work-up
In 6 months

13. Decisionnal factors
Tumor volume
Age
Hearing function

14. Therapeutic options Conservative managament Radiotherapy Surgery
Varaiable tumor growth
According to age and tumor size < 1,5 cm
MRI in 6 months and then once a year
Conservative managament
Radiotherapy
Gamma-knife, LINAC
Volume stabilisation
Hearing loss and facial paresis
Under evaluation
Surgery

15. Goals of the surgery 1- Minimal vital and neurological risks
2- Total removal
3- Facial function preservation
4- Hearing preservation

16. Approaches Middle cranial fossa (MCF) Retrosigmoid (RS)
Translabyrinthine (TL)

17. Acoustic Neuromas CPA> 20 mm Translabyrinthine or transotic
Intracanalar or CPA < 20 mm
> 70 years:
Conservative
management
< 70 years:
Surgery
Poor general condition:
Irradiation
Hearing
Serviceable
Unserviceable
MCF
retrosigmoid
translabyrinthine

18. Population 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 %
II < 15 mm
III : mm
IV > 30 mm I

19. Approaches Translabyrinthine : 77 % Transotic: 6 % Retrosigmoid: 12 %
Middle cranial fossa: %
17% attempt to hearing preservation

20. Intraoperative monitoring
ABR

21. Direct cochlear nerve potential

22. 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 %)

23. Postoperative facial function in translabyrinthine or transotic approach
Stages
Cases
　　　　Facial function
　1　　2　　3　　4　　5　　6 总计 83

24. Hearing preservation
Hearing preservation attempts by middle cranial fossa or retrosigmoid approach (n=17):
Class C: 24 %
Class D: 40 %
Class B: 24 %
Class A: 12 %
Class A+B: 36%

25. Complications CSF leaks: 6%(all in first 39 cases) Neurological: 3%
Infectious: 1 %
Miscellaneous: 3 %

26. Translabyrinthine approach

27. 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

28. 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

29. Fallopian bridge technique

30. Middle fossa approach

32. Retrosigmoid-IAM approach

33. Facial nerve repair after interruption
end-to-ent anastomosis
Reroute technique
Bridge technique
Facial-hypolingual ana.

34. Hearing rehabilitation in acoustic neuroma surgery
NF2 and Auditory Brainstem Implant

35. NF2 DIAGNOSIS Bilateral vestibular schwannoma (VS)
NF2 familial history
and
- unilateral VS
- or 2 among : meningioma, glioma, neurofibroma,schwannoma,subcapsular lens opacity

36. NF2
NF2 gene on chromosome 22 (1993)
Tumor suppressor gene

37. Auditory pathway

38. Nucleus 21 Channel Auditory Brainstem Implant
Removeable
magnet
CI22M receiver-stimulator
Monopolar
reference electrode
(plate)
Microcoiled electrode
wires
T-shaped
Dacron
mesh
Electrode array
(21 platinum disks
0.7mm diameter)

40. Bone anchored hearing aide (BAHA)
Single sided deafness;
FDA approval;

41. 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.

42. 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.

43. Thanks