Commentary

The authors reported 14 patients surgically treated for petroclival meningiomas in whom the sigmoid or transverse sinus was ligated. Based on their preoperative arteriograms, venous drainage patterns (available for only 11 patients) were classified into four categories: four were Type A (equal size sinuses with confluence), five were Type B (nondominant sinus ligated with confluence), and two were Type C (dominant sinus ligated with confluence).

One can probably conclude that ligation of the sinus is tolerated in patients with Type A and B configurations. However, the numbers are insufficient to state that the dominant sinus can be ligated without problems in every instance when a confluence is present. In my own observation of this procedure, the patient developed severely elevated intracranial pressure with florid papilledema and visual loss. An urgent venous bypass did not remain patent, and a ventriculoperitoneal shunt did not reverse the deficits.

In my practice, I do not always perform a venous study before surgery. I measure the proximal sinus pressure before and after temporary clipping. If the intrasinus pressure does not show any change with temporary occlusion, I feel it is safe enough to be ligated. If the pressure rises at all, I do not sacrifice the sinus. Instead, I leave the sinus intact and place a vessel loop around the sinus and work in front of it and behind it as needed. Perhaps, according to the authors, if the preoperative venous study shows a Type A or B pattern, pressure measurements may be unnecessary when sacrificing the sinus. Fortunately, for the resection of petroclival meningiomas using contemporary skull base approaches, the need for sinus ligation is quite infrequent.