1. Vestibular Schwannoma Surgical management and outcomes
Ching-Jen (Jared) Chen
Visiting Sub-Intern
University of Virginia

2. Patient MM 48yo M w/ L-sided tinnitus and dysequilibrium since 2009.
MRI 2010 revealed 5mm L vestibular schwannoma (purely intracanalicular).
No intervention, followed with serial scans.
MRI 2012 revealed schwannoma had extended to just outside the IAC.
Audiogram showed mild L sensorineural hearing loss.
Referred to MGH for surgical consideration.

3. Patient MM (cont’d) PMH: SH: Denies tobacco and illicits, rare EtOH.
Hx of Afib w/ spontaneous conversion to NSR
Viral pericarditis
S/p R knee surgery
S/p R shoulder surgery
SH: Denies tobacco and illicits, rare EtOH.
FH: Non-contributory, no hx of vestibular schwannomas.
MEDS: ASA 81 QDaily
ALL: NKDA
EXAM: NI, except slightly decreased hearing in L ear
Decided to undergo microsurgical resection via retrosigmoid approach

4. T1-PostGad
2010
2012
2013
5mm L Vestibular Schwannoma, purely intracanalicular.
Enlarging L Vestibular Schwannoma, 11mm. Projects just beyond medial aspect of porous acusticus.
6 mo s/p microsurgical GTR, via retrosigmoid approach. W/o evidence of residual/recurrent tumor.

5. Vestibular Schwannoma
Usually arise from the superior division of vestibular n.
Histology: Antoni A, Antoni B, and Verocay Bodies.
Comprising 8-10% of intracranial tumors.
Annual incidence ~1.5 cases/100,000.
Typically become symptomatic after age 30.
Most common symptoms: hearing loss, tinnitus, and dysequilibrium.
>95% are unilateral. B A
Wippold FJ et al.

6. Treatment options Microsurgery Radiosurgery Middle Fossa approach
Translabyrinthine approach
Retrosigmoid approach
Radiosurgery
Mayfield clinic

7. Middle Fossa Approach
Gonzalez LF et al.
Usually selected for smaller (<25mm) and laterally place tumors.
Potential damage to temporal lobe w/ risk of seizures.

8. Retrospective review; 46 patients, middle fossa approach.
Mean follow-up time: 1.8 yr.
Mean tumor size 8.3mm.
Facial n.
Excellent/good (House-Brackmann Grade I-II) functional preservation: 89.1%.
Not correlated w/ tumor size.
Cochlear n.
Functional hearing (AAO-HNS Class A-B) preservation: 63.2%
Hearing preservation related to tumor size.

9. Translabyrinthine Approach
Allows resection of tumors of different sizes.
Disadvantage:
Sacrifices hearing
Longer procedure
Gonzalez LF et al.

10. Retrospective review, 1244 patients, translabyrinthine approach.
All patients at least 12mo of f/u.
Gross total resection 84%, near-total 13.7%, subtotal 2.2%.
Facial n.
Excellent/good (House-Brackmann Grade I-II) functional preservation: 70.3%
Tumor size significantly correlates w/ post-op facial n. function.

11. Retrosigmoid Approach
Most commonly used approach.
Allows resection of tumors of different sizes and wide view of cisternal component of tumor.
Disadvantage:
Cerebellar retraction (not a problem for smaller tumors, <40mm)
Less access to facial/cochlear n. in distal IAC
Headaches
Gonzalez LF et al.

12. Retrospective review; 200 consecutive patients, retrosigmoid approach.
Mean follow-up time: 24 mo.
Gross total resection: 98%, Subtotal resection: 2%.
Tumor recurrence: 0.5%.
Facial n.
Excellent/good (House-Brackmann Grade I-II) functional preservation: 62%.
Tumor size significantly correlates w/ post-op facial n. function (p<0.05).
Cochlear n.
Functional hearing (New Hannover Classification Grade I-III) preservation: 51%.
Hearing preservation related to tumor size and extension, and pre-op hearing level (p<0.05).

13. Radiosurgery Alone or in conjunction with surgery.
Usually reserved for small to medium sized tumors, or patients who are poor surgical candidates.

14. Retrospective review, 190 patients treated with GKRS.
Primary treatment 70.5% and adjunctive 29.5%.
Median margin dose 13Gy, tumor volume 3.6cm3, f/u 109mo.
Overall tumor control rate 89.5%.
Estimated 3-, 5-, 10- and 15-year tumor control rates: 95%, 93%, 86%, and 70%, respectively.
Hearing preservation rate 75%.
Estimated 3-, 5-, and 10-year tumor control rates:, 96%, 92%, and 70% respectively.
Facial n. function (House-Brackmann Grade I-II) preservation 98.6%.
Tumor control was significantly affected by tumor volume.

15. Patient MM (cont’d) At 6mo f/u, pt has been doing well.
Stable tinnitus and hearing loss.
Exam unchanged, incision c/d/i.
No specific complaints.
F/u visit in 6mo w/ MRI and audiogram.

16. Conclusions
Microsurgery appears to offer better tumor control rates, whereas radiosurgery seems to have higher hearing preservation.
Treatment selection should be tailored to each individual patient and tumor characteristics.
Surgeon/institution experience should also be taken into consideration.
Gonzalez LF et al.

17. Acknowledgements Mark E. Shaffrey, MD John A. Jane Sr., MD PhD
Justin S. Smith, MD PhD
Christopher I. Shaffrey, MD
Jason P. Sheehan, MD PhD
Robert L. Martuza, MD
William T. Curry, MD
Department of Neurosurgery

18. References
Samii M, Gerganov V, Samii A: Improved preservation of hearing and facial nerve function in vestibular schwannoma surgery via the retrosigmoid approach in a series of 200 patients. J Neurosurg 105:
Gonzalez LF, Lekovic GP, Porter RW, Syms MJ, Daspit CP, Spetzler RF: Surgical approaches for resection of acoustic neuromas. Barrow Quarterly 20(4):
Wippold FJ, Lubner M, Perrin RJ, Lammle M, Perry A: Neuropathology for the neuroradiologist: antoni a and antoni b tissue patterns. AJNR 28:
Sun S, Liu A: Long-term follow-up studies of gamma knife surgery with a low margin dose for vestibular schwannoma. J Neurosurg 117:
Springborg JB, Fugleholm K, Poulsgaard L, Caye-Thomasen P, Thomsen J: Outcome after translabyrinthine surgery for vestibular schwannomas: report on 1244 patients. J Neurol Surg B 73:
Kutz JW, Scoresby T, Isaacson B, Mickey BE, Madden CJ, Barnett SL, Coimbra C, Hynan LS, Roland PS: Hearing preservation using the middle fossa approach for the treatment of vestibular schwannoma. Neurosurgery 70: