1) A 58-year-old woman presented with right-sided facial spasms after undergoing resection of a right-sided acoustic neuroma in 2005. 2) A literature search found few papers directly addressing microvascular decompression for hemifacial spasm after excision of cerebellopontine angle lesions. 3) One study of 652 patients who underwent acoustic neuroma resection found a 13% chance of developing hemifacial spasm after surgery, with a 42% chance of resolution within 24 months. However, no reports were found of surgery for persistent hemifacial spasm after a previous procedure.

1. EBS
Microvascular Decompression for Hemi Facial Spasm
After Excision of Acoustic Neuroma
Macquarie Neurosurgery
Evidence Based Surgery presentation
Date: 25/2/16
By Dr Chris Davidoff

2. Clinical case
58yr old enrolled nurse presents with right sided facial spasms
• removal of right sided acoustic neuroma in 2005
• started having right sided facial spasms and tinnitus in 2012
• progress scans showed no recurrence of tumour
• reviewed by neurologist and multiple medical therapies trialled
• trialled botox therapy twice without relief
• ongoing severe spasm and tinnitus, starting to affect her ability to
work
• desperate to undergo microvascular decompression

3. Clinical case

4. Searchable question (PICO format)
P – Patients who have hemifacial spasm after resection of a
cerebellopontine angle lesion
I – microvascular decompression or surgical management
C – none
O – surgical success rate and/or complication rate
Question: “What is the role of surgery for hemi facial spasm after excision
of a cerebellopontine angle lesion?”

5. Search strategy
• Medline
• Embase
• Scopus
• Cochrane Library

6. Search results
Initial Medline search

7. Search results
Medline search

8. Search results
Embase search

9. Search results
Scopus search

10. Search results
Cochrane Search

11. Prisma Flow Diagram
Medline 18 articles Embase 48 articles Scopus 111 articles Cochrane 1 article
143 Abstracts reviewed
5 Articles retrieved
138 Excluded
- 137 irrelevant
- 1 inaccessible
0 Papers reviewed
5 excluded

12. Summary of papers
• retrieved as it was a case series of HFS caused by CP angle tumours
• aimed to investigate the possibility that one of the cases had received an
operation prior to GK

13. Summary of papers
• single case report study
• retrieved to see if there was a relevant cross over between HFS and
hemimasticatory spasm
• reviewed to ascertain how the spasm was managed in the post-
operative period

14. Summary of papers
• case series of 9 patients with HFS as the result of CP angle tumours
• retrieved to ascertain if any of the patients’ HFS did not resolve as the
result of surgery
• 2 cases had HFS recur – 1 as a result of subtotal resction of AN, 1 due
to thickened arachnoid due to “inflammatory changes”
• no comment made as to whether re-operation was attemped

15. Summary of papers
• retrospective cohort study of 652 patients undergoing surgical resection
of AN
• 61 patients had HFS at 3 months post-op – this improved in 45 patients
at 24 months and persisted in 16 patients
• 17 patients developed HFS between 3-24 months post-op
• showed a 13% chance of developing HFS in the post-op period, with a
42% chance it would resolved in 24 months

16. Summary of papers
• single case study on HFS and AN being treated by a single GK
exposure
• retrieved to investigate the possibility that HFS was treated after AN
received GK therapy
• reported that the HFS was likely secondary to AN and that GK therapy
resolved the HFS

17. Further Search

18. Further Search

19. Difficulties of search
• Difficult to construct a search delineating MVD for HFS after AN resection
• Re-operation search strategies focused on failure of MVD surgery, not
for MVD after previous surgery
• Relative paucity of papers on HFS
• Broadening search to include CP angle tumours netted multiple papers
focusing on gamma knife surgery
• Looking for individual case results resulted in having to read through
many abstracts and papers

20. Conclusions
• 13% chance of developing HFS after surgical resection of AN
• 42% chance it will resolve in 24 months
• no reports of anyone operating for persisting HFS after previous surgery