COMBINED SUPRA INFRATENTORIAL-TRANSSINUS APPROACH TO LARGE PINEAL REGION TUMORS/

Object. The authors sought to confirm that the combined supra/infraten torial-transsinus approach offers a safer means of resecting large pin eal region tumors than other approaches currently being used. The afor ementioned method provides a wider exposure of the pineal region with less brain retraction than the infratentorial-supracerebellar or the o ccipital-transtentorial approach alone and is applicable to some large and giant tumors of this area. This combined approach was used in six patients to remove large pineal region tumors including four tentoria l meningiomas, one pineocytoma, and one epidermoid cyst. Methods. The transverse sinus and tentorium were sectioned after review of preopera tive angiographic studies, after taking intraoperative measurements of the venous pressure in the nondominant transverse sinus before and af ter clipping and while monitoring the somatosensory evoked potentials. The occipital lobe cortex and cerebellum were retracted slightly alon g the tentorium. Deep veins of the galenic system, the quadrigeminal a rea, and the tumor were well exposed. Before it was used for tumor res ection the approach was studied in five cadaveric head specimens, and the projection of different approaches was compared radiologically. Th e tumors were removed in a gross-total manner in all patients, and non e of the major veins of the galenic system was injured. Resuturing of the nondominant transverse sinus was performed postoperatively in one patient. One of the six patients experienced transient visual loss, an d another suffered mild right sixth cranial nerve paresis; however, bo th re covered in 3 weeks. The wide exposure of the combined approach w as also confirmed on radiological and anatomical studies. Conclusions. The combined supra/infratentorial-transsinus approach is preferred fo r the resection of certain large pineal region tumors.