Retrolabyrinthine Trans-Sigmoid (RLTS) Approach to Aneurysms of the Basilar Trunk and Vertebrobasilar Junction: an Update

Summary

Traditionally, approaches for vertebral basilar junction and basilar trunk aneurysms have been complicated by excessive temporal lobe, brainstem, or cerebellar retraction, and by long reaches through narrow corridors bounded by interposed cranial nerves. The author has successfully developed and utilized an approach with a trajectory through the mastoid which reduces the working distance between the surface and the basilar artery and obviates the need for virtually any significant cerebellar retraction and no brainstem retraction. Mastoid air cells are removed anterior and posterior to the sigmoid sinus. The anterior extent of the removal is the posterior semicircular canal. The superior extent of removal is the superior petrosal sinus, and the inferior extent of removal is the jugular bulb. By including a small amount of bone removal posterior to the sigmoid sinus, the sigmoid sinus is then ligated at its junction with the jugular bulb and superior petrosal sinus and it and the dura are reflected anteriorly. With the patient in the supine position with the head turned 60 degrees away from the side of the approach, the pontine and medullary cisterns are easily accessible without cerebellar or brain-stem retraction. Nine cases have been treated utilizing this approach. There was one death of a patient with a giant basilar trunk aneurysm which could not be successfully ligated and subsequently suffered a fatal recurrent subarachnoid hemorrhage four weeks post-operatively. The remaining eight patients made good recoveries. There were two lower cranial nerve deficits which resolved spontaneously. Hearing was preserved in all nine surviving cases. There have been no complications related to selective occlusion of the sigmoid sinus.