Background: Lesions located in the posterolateral brain stem, particularly the middle cerebellar peduncle, have presented surgeons with a challenge associated with significant morbidity.
Methods: We present a case of a 20-year-old woman who had a hematoma in the right middle cerebellar peduncle with a ventricular rupture. Angiography revealed an arteriovenous malformation (AVM) located in the same portion, extending from the lateral surface near the entry zone of the trigeminal nerve to the paraventricular area of the fourth ventricle, which was completely resected through a posterior transpetrosal approach. We also describe the microsurgical anatomy of this region in a cadaveric specimen, presenting the anatomic landscape at the target when approaching through this route.
Results: The patient's postoperative course was uneventful and her neurologic deficits progressively but gradually improved. When a lesion exists at or close to the surface of the middle cerebellar peduncle, the best approach, in our estimation, is a transpetrosal approach because the lesion can be approached perpendicularly with a short working distance, various angles for dissection are available, and minimal retraction of the temporal lobe and cerebellum is required.
Conclusion: An AVM embedded in the middle cerebellar peduncle can be successfully resected using a posterior transpetrosal approach, though we concede this approach is slightly labor-intensive and time-consuming.