Vestibular SchwannomaSurgical management and outcomes

Ching-Jen (Jared) ChenVisiting Sub-Intern

University of Virginia

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.

Patient MM (cont’d)

• PMH:– 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

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.

T1-PostGad

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.

Wippold FJ et al.A

B

Treatment options

• Microsurgery– Middle Fossa approach– Translabyrinthine approach– Retrosigmoid approach

• RadiosurgeryMayfield clinic

Middle Fossa Approach• Usually selected for smaller (<25mm)

and laterally place tumors.

• Potential damage to temporal lobe w/ risk of seizures.

Gonzalez LF et al.

• 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.

Translabyrinthine Approach

• Allows resection of tumors of different sizes.

• Disadvantage:– Sacrifices hearing– Longer procedure

Gonzalez LF et al.

• 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.

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.

• 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).

Radiosurgery• Alone or in conjunction with surgery.• Usually reserved for small to medium sized tumors, or

patients who are poor surgical candidates.

• 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.

• 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.

Patient MM (cont’d)

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.

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

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: 527-535. 2006.

• Gonzalez LF, Lekovic GP, Porter RW, Syms MJ, Daspit CP, Spetzler RF: Surgical approaches for resection of acoustic neuromas. Barrow Quarterly 20(4): 22-32. 2004.

• Wippold FJ, Lubner M, Perrin RJ, Lammle M, Perry A: Neuropathology for the neuroradiologist: antoni a and antoni b tissue patterns. AJNR 28: 1633-1638. 2007.

• Sun S, Liu A: Long-term follow-up studies of gamma knife surgery with a low margin dose for vestibular schwannoma. J Neurosurg 117: 57-62. 2006.

• 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: 168-174. 2012.

• 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: 334-341. 2012.