[Resection of brainstem cavernous malformations via lateral approaches].

Objective: To explore the surgical indications and efficacy of lateral approaches in the removal of brainstem cavernous malformations retrospectively.
Methods: From July 1999 to June 2008, 10 cases of brainstem cavernous malformations were removed via lateral approaches. Four of them had reached the lateral pial surface and 6 were covered by parenchyma or glial tissue. Three lesions were located dorsal to the cranial nerve roots and 4 lesions rostral to the facial nerve root. All 7 lesions were removed via the retrosigmoidal approach. Far lateral approach was used for 2 cases with the lesions ventral or caudal to the posterior cranial nerves. Subtemporal approach was adopted in 1 patient with the lesion ventral and rostral to the trigeminal nerve. The preoperative visual reality technique, in combination with intraoperative neuronavigation, was employed in the recent 3 cases to select a safe entry point on the surface of brainstem and a surgical corridor so as to maintain minimal damage to the surrounding fiber tracts and cranial nerve nuclei.
Results: Total lesion removal was achieved in all patients. Four cases of associated venous malformation were all preserved. The mean NIHSS score was 1.1 after a mean post-operative follow-up of 41 months. Eight patients improved, 1 worsened and 1 remained unchanged versus the preoperative state.
Conclusion: Lateral approaches are recommended for lesions reaching the lateral glial surface or accessible via the lateral safe entry zone approaches.