Introduction: Class II evidence suggests that extent of resection in malignant glioma prolongs overall survival and delays radiologic progression; Class III evidence suggests that gross total resection (GTR) prolongs recurrence in transsphenoidal hypophysectomy (TSH) for pituitary adenomas (ref1,2). Operative room (OR) time reflects the cost and risk imposed by surgery. Increased time is justifiable when more value is added or risk averted and conceptually OR time should vary directly with tumor resection. This notion has never been tested in neurosurgical paradigms. We examined the relationship of volumetric resection to OR time in three paradigms: transcranial tumor resection, TSH for endoscopic pituitary resection and microscopic pituitary resection.

Methods: A single-center retrospective chart review was performed. All supra- and infratentorial transcranial resections and all endoscopic and microscopic sellar approaches were eligible. Tumor volume resected was calculated using OSIRIX software comparing pre- and postoperative MRI. Correlation of operative time to tumor volume was assessed via the Pearson Correlation Coefficient.

Results: 41 endoscopic pituitary resections (group A), 45 microscopic pituitary resections (group B) and 29 transcranial tumor resections (group C) were identified. Mean resected tumor volumes for group A, B and C were 6.78mm^3, 3.68mm^3, and 25.58 cm^3, respectively. There was a statistically significant correlation between volume of tumor resection and operative time in groups A (r= 0.345, r^2= 0.119, P value = 0.027), and B (r= 0.389, r^2= 0.151, P value = 0.008). No correlation between volume resected and operative time was found in group C (r= 0.0592, r^2= 0.0035, P value = 0.760).

Conclusions: Endoscopic and microscopic transsphenoidal surgery are standardized approaches to sellar pathology, with a stronger correlation between OR time and volume of resection. Transcranial tumor resection relates OR time with volume of resection poorly. This is attributed partly to a wider variability of resection methods and lack of surgical efficiency, which warrant further investigation.

Patient Care: The wide variability of brain tumor resection methods and lack of surgical efficiency will benefit from a root cause analysis aimed at optimizing patient outcomes in relation to expenditure of medical resources.

Learning Objectives: By the conclusion of this session participants should understand that: 1. Increased OR time is weakly correlated with percent tumor resection. 2. There is benefit in analyzing special cause variability within tumor resection practice. 3. Value in health care is pervasive and should be applied by neurosurgeons to improve neurosurgical practices.

References: 1. Keles GE, Anderson B, Berger MS. The effect of extent of resection on time to tumor progression and survival in patients with glioblastoma multiforme of the cerebral hemisphere. Cancer, 1999; 74:1784-1791. 2. Chang EF, Zada G, Kim S, Lamborn KR, Quinones-Hinojosa A, Tyrrell JB, Wilson CB and Kunwar S. Long-term recurrence and mortality after surgery and adjuvant radiotherapy for nonfunctional pituitary adenomas. J Neurosurgery, 2008. 108: 736-745.