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Objective The transition from microscopic to fully endoscopic transsphenoidal surgery requires a surgeon to assess how the change in technique will affect the extent of tumor resection (EOR), outcomes, and complications. We compared a single surgeon's experience transitioning from one technique to the other and examined the operative outcomes and EOR between microscopic versus endoscopic transsphenoidal surgery. Methods Retrospective data analysis of adult patients who were treated surgically for a pituitary adenoma between August 2005 and May 2015 by a single neurosurgeon, who was originally trained and practiced in the microscopic transsphenoidal approach. Patient demographics, perioperative conditions, tumor characteristics, operative times, volumetric EOR, postoperative outcome, and the endoscopic learning curve were evaluated. Results One hundred and nine patients underwent microscopic transsphenoidal surgery and 275 patients underwent a fully endoscopic approach. The patient characteristics were similar in the 2 groups. Operative room time was significantly shorter in the endoscopic group than in the microscopic group (180.2 vs. 215.6 minutes; P < 0.001). The endoscopic and microscopic groups had similar volumetric EOR (85.1% vs. 82.8%; P = 0.371) as well as residual tumor volume (1.06 cm 3 vs. 1.15 cm 3 ; P = 0.765). The mean length of hospital stay was 2.4 days in the endoscopic group and 3.2 days in the microscopic group ( P = 0.03). Conclusions During the transition from the microscopic to the endoscopic approach, similar surgical outcomes and EOR were achieved in the 2 cohorts. In our experience, the endoscopic approach offers the advantage of shorter operative times and lengths of hospital stays after the surgeon has developed more experience with the technique. [ABSTRACT FROM AUTHOR]

Objective Aneurysms of the anterior pontine segment of the anterior-inferior cerebellar artery (AICA) are uncommon. Their treatment is challenging because critical neurovascular structures are adjacent to it and the available surgical corridors are narrow and deep. Although endoscopic endonasal approaches are accepted for treating midline skull base lesions, their role in the treatment vascular lesions remains undefined. The present study is aimed to assess the anatomic feasibility of the endoscopic endonasal transclival (EET) approach for treating anterior pontine AICA aneurysms and compare it with the subtemporal anterior transpetrosal (SAT) approach. Methods Twelve cadaveric specimens were prepared for surgical simulation. The AICAs were exposed using both EET and SAT approaches. Surgical window area and the length of the exposed artery were measured. The distance from the origin of the artery to the clip applied for proximal control was measured. The number of AICA perforators exposed and the anatomic features of each AICA were recorded. Results The EET approach provided a wider surgical window area compared with the SAT ( P < 0.001). More AICA perforators were visualized using the EET approach ( P < 0.05). To obtain proximal control of the AICA, an aneurysm clip could be applied closer to the origin of AICA using EET (0.2 ± 0.42 mm) compared with SAT (6.26 ± 3.4 mm) ( P < 0.001). Conclusion Clipping anterior pontine AICA aneurysms using the EET approach is feasible. Compared with SAT, the EET approach provides advantages in surgical window area, ensuring proximal control before aneurysm dissection, visualization of perforating branches, and better proximal control. [ABSTRACT FROM AUTHOR]

Objective: The main aim of our study was to analyze and compare the surgical anatomy pertinent to the dorsal transcranial transcondylar (far lateral approach) with that of the ventral endoscopic endonasal transcondylar (far medial approach) route. Methods: Eight cadaveric specimens were dissected and analyzed bilaterally. Brainstem exposure and surgical corridor areas were measured. In addition, we present three clinical scenarios to illustrate the clinical feasibility of the proposed surgical strategies. Results: The hypoglossal nerve, vertebral artery, and hypoglossal canal divide the lower third of the clivus into ventromedial and dorsolateral compartments. The far medial approach provides significantly larger exposure of the brainstem in the ventromedial compartment (464.6 ± 68.34 mm2) compared with the far lateral approach (126.35 ± 32.25 mm2), P < 0.01. The far lateral approach provides a wide exposure of the brainstem in the dorsolateral compartment (295.24 ± 58.03 mm2, 74% of the dorsolateral compartment). The exposure of the brainstem in the dorsolateral compartment is not possible using the endonasal route. The surgical corridor from one compartment to the other, through the lower cranial nerves, was significantly larger on the far lateral approach (78.19 ± 14.54 mm2) than on the far medial (23.77 ± 15.17 mm2), P = 0.03. Conclusions: The far medial approach offers a safe, wide exposure of the lower third of the clivus for lesions that expand ventromedial to the hypoglossal nerve. The far lateral approach is most suitable for lesions located dorsolateral to the lower cranial nerves. The vertebral artery and hypoglossal canal are the most important landmarks to guide surgical planning. A combined endonasal-transcranial approach should be considered for resection of extensive lesions involving both ventromedial and dorsolateral compartments. We strive to encourage skull base surgeons to integrate endoscopic and microscopic approaches to the posterior fossa. [ABSTRACT FROM AUTHOR]