Intradural "limited drill" technique of anterior clinoidectomy and optic canal unroofing for microneurosurgical management of ophthalmic segment and PCOM aneurysms-review of surgical results.

To evaluate the safety and efficacy of intradural "limited drill" technique (ILDT) of anterior clinoidectomy (AC) and optic canal unroofing (OCU) for microneurosurgical management of ophthalmic segment and posterior communicating artery (PCOM) aneurysms. All the patients with ophthalmic segment and PCOM aneurysms who underwent AC and OCU by ILDT for microneurosurgical management of ophthalmic segment and PCOM aneurysms during 4-year period (2013-2016) at our Institute were included in this study. In ILDT of AC and OCU, the use of power drill is restricted to AC only and OCU is done exclusively with 1-mm Kerrison punch. AC and OCU by ILDT were done in 24 patients with 29 ophthalmic segment and 7 PCOM aneurysms. AC and OCU by ILDT helped in mobilization of optic nerve/internal carotid artery (ICA) and provided excellent exposure for all these aneurysms. There was no injury to ICA or optic nerve during drilling. AC and OCU facilitated clip ligation of 34 of these aneurysms. Remaining 2 aneurysms were considered not suitable for clipping. Check angiogram done for 33 aneurysms revealed complete obliteration of 26 aneurysms, very small residual neck in 5 aneurysms, and small residual aneurysm in 2 aneurysms. Deterioration in vision was noted in 1 patient (4.1%). In 6 patients with preoperative visual deficits, significant improvement in vision was noted in 4 patients (4/6-66.6%) after surgery. Good outcome (MRS < 2) was noted in 91.6% (22/24) of these patients. ILDT is a safe and effective technique of AC and OCU which provide good exposure for ophthalmic segment and PCOM aneurysms.

Subgaleo-peritoneal shunt: An effective and safer alternative to lumboperitoneal shunt in the management of persistent or recurrent iatrogenic cranial pseudomeningoceles.

Subgaleo-peritoneal (SP) shunting for pseudomeningoceles (PMCs) is an effective and safer alternative as compared to the lumboperitoneal (LP) shunt. SP shunting was done in six patients (14-60 years) with persistent or recurrent PMCs using the cranial (ventricular part) and the distal parts of a Chhabra shunt connected by a rigid connector without any intervening chamber or valve. Two patients had undergone a prior LP shunt that had failed. One patient was unsuitable for a LP shunt placement. The PMC subsided completely in all the patients following the SP shunt. In one patient, the shunt got displaced and required repositioning. None of the patients developed symptoms of over-drainage or any other complication. All patients were asymptomatic at a mean follow-up of 15 months. These results suggest that SP shunting is a safe, simple, and effective alternative to the traditional LP shunt in the management of persistent or recurrent cranial PMCs.

Safety and Accuracy of Anatomic and Lateral Fluoroscopic-Guided Placement of C2 Pars/Pedicle Screws and C1 Lateral Mass Screws, and Freehand Placement of C2 Laminar Screws.

OBJECTIVE: To evaluate the safety and accuracy of anatomic- and lateral fluoroscopic-guided placement of C2 pars/pedicle, C1 lateral mass screws, and freehand placement of C2 laminar screws. METHODS: All the patients who underwent posterior cervical/occipitocervical fixation that involved the placement of C1/C2 screws during a 5-year period (2011-2015) at our institute were included in this study. RESULTS: C1/C2 screws were placed in a total of 94 patients during this period. A total of 97 C1 lateral mass, 49 C2 pars, 24 C2 pedicle, and 82 C2 laminar screws were placed in these patients. C1 lateral mass screws and C2 pars/pedicle screws were placed under anatomic and lateral fluoroscopic guidance. C2 laminar screws were placed by a freehand technique. The mean length (range) of various C2 screws was 16.4 ± 2.6 mm (12-22 mm) for pars screws, 18.8 ± 2.7 mm (14-24 mm) for pedicle screws, and 25.6 ± 3.4 mm (18-32 mm) for laminar screws. Postoperative CT imaging done in all patients before discharge revealed malposition of 2 laminar screws with breach of the inner cortex. The position of the remaining C1/C2 screws was perfect. The superior and medial angulation of the pars screws and superior angulation of the pedicle screws as measured in postoperative CT images were found to significantly deviate from the angles described in the literature. There was no mortality, vertebral artery injury, or neurologic injury related to C1/C2 screw placement in this series. CONCLUSIONS: Anatomic and lateral fluoroscopic-guided placement of C2 pars/pedicle screws and C1 lateral mass screws and freehand placement of C2 laminar screws is extremely safe.