Faculty Bibliography

Object The definition and determination of quality health care is an important topic. The purpose of this study was to develop a longitudinal method to define a quality procedure by creating a formal approach to pre- and postoperative outcomes documentation. The authors worked to define quality outcomes by first documenting the patient's condition. Goals were determined together by the surgeon and the patient and then were evaluated to see if those goals were met. Methods The population consisted of cancer patients with newly diagnosed metastatic brain disease who were scheduled to undergo stereotactic radiosurgery. Surgeons recorded perioperatively objective information related to preoperative goals, clinical findings, surgical performance and/or error, and whether goals were met. In addition, patients completed pre- and postprocedure questionnaires (Rand 36-Item Short-Form Health Survey 1.0 [SF-36]). Results Procedural goals, defined as completing radiosurgery without error or complication and same-day discharge, were met in all patients. The clinically predetermined goal of tumor palliation was met in all but 1 patient at follow-up. The SF-36 scores remained stable except for the general health domain, which was lower (p = 0.006). Conclusions Procedural goals can be defined and objectively measured serially. The authors think that quality care can be defined as a process that achieves predefined goals without significant error and maintains or improves health.

Object Pituitary adenomas are fairly common intracranial neoplasms, and nonfunctioning ones constitute a large subgroup of these adenomas. Complete resection is often difficult and may pose undue risk to neurological and endocrine function. Stereotactic radiosurgery has come to play an important role in the management of patients with nonfunctioning pituitary adenomas. This study examines the outcomes after radiosurgery in a large, multicenter patient population. Methods Under the auspices of the North American Gamma Knife Consortium, 9 Gamma Knife surgery (GKS) centers retrospectively combined their outcome data obtained in 512 patients with nonfunctional pituitary adenomas. Prior resection was performed in 479 patients (93.6%) and prior fractionated external-beam radiotherapy was performed in 34 patients (6.6%). The median age at the time of radiosurgery was 53 years. Fifty-eight percent of patients had some degree of hypopituitarism prior to radiosurgery. Patients received a median dose of 16 Gy to the tumor margin. The median follow-up was 36 months (range 1-223 months). Results Overall tumor control was achieved in 93.4% of patients at last follow-up; actuarial tumor control was 98%, 95%, 91%, and 85% at 3, 5, 8, and 10 years postradiosurgery, respectively. Smaller adenoma volume (OR 1.08 [95% CI 1.02-1.13], p = 0.006) and absence of suprasellar extension (OR 2.10 [95% CI 0.96-4.61], p = 0.064) were associated with progression-free tumor survival. New or worsened hypopituitarism after radiosurgery was noted in 21% of patients, with thyroid and cortisol deficiencies reported as the most common postradiosurgery endocrinopathies. History of prior radiation therapy and greater tumor margin doses were predictive of new or worsening endocrinopathy after GKS. New or progressive cranial nerve deficits were noted in 9% of patients; 6.6% had worsening or new onset optic nerve dysfunction. In multivariate analysis, decreasing age, increasing volume, history of prior radiation therapy, and history of prior pituitary axis deficiency were predictive of new or worsening cranial nerve dysfunction. No patient died as a result of tumor progression. Favorable outcomes of tumor control and neurological preservation were reflected in a 4-point radiosurgical pituitary score. Conclusions Gamma Knife surgery is an effective and well-tolerated management strategy for the vast majority of patients with recurrent or residual nonfunctional pituitary adenomas. Delayed hypopituitarism is the most common complication after radiosurgery. Neurological and cranial nerve function were preserved in more than 90% of patients after radiosurgery. The radiosurgical pituitary score may predict outcomes for future patients who undergo GKS for a nonfunctioning adenoma.

OBJECT: The surgical management of disabling tremor has gained renewed vigor with the availability of deep brain stimulation. However, in the face of an aging population of patients with increasing surgical comorbidities, noninvasive approaches for tremor management are needed. The authors' purpose was to study the technique and results of stereotactic radiosurgery performed in the era of MRI targeting. METHODS: The authors evaluated outcomes in 86 patients (mean age 71 years; number of procedures 88) who underwent a unilateral Gamma Knife thalamotomy (GKT) for tremor during a 15-year period that spanned the era of MRI-based target selection (1996-2011). Symptoms were related to essential tremor in 48 patients (19 age >/= 80 years and 3 age >/= 90 years), Parkinson disease in 27 patients (11 age >/= 80 years [1 patient underwent bilateral procedures]), and multiple sclerosis in 11 patients (1 patient underwent bilateral procedures). A single 4-mm isocenter was used to deliver a maximum dose of 140 Gy to the posterior-inferior region of the nucleus ventralis intermedius. The Fahn-Tolosa-Marin clinical tremor rating scale was used to grade tremor, handwriting, and ability to drink. The median follow-up was 23 months. RESULTS: The mean tremor score was 3.28 +/- 0.79 before and 1.81 +/- 1.15 after (p < 0.0001) GKT; the mean handwriting score was 2.78 +/- 0.82 and 1.62 +/- 1.04, respectively (p < 0.0001); and the mean drinking score was 3.14 +/- 0.78 and 1.80 +/- 1.15, respectively (p < 0.0001). After GKT, 57 patients (66%) showed improvement in all 3 scores, 11 patients (13%) in 2 scores, and 2 patients (2%) in just 1 score. In 16 patients (19%) there was a failure to improve in any score. Two patients developed a temporary contralateral hemiparesis, 1 patient noted dysphagia, and 1 sustained facial sensory loss. CONCLUSIONS: Gamma Knife thalamotomy in the MRI era was a safe and effective noninvasive surgical strategy for medically refractory tremor in the elderly or those with contraindications to deep brain stimulation or stereotactic radiofrequency (thermal) thalamotomy.

Object The first North American 201 cobalt-60 source Gamma Knife surgery (GKS) device was introduced at the University of Pittsburgh Medical Center in 1987. The introduction of this innovative and largely untested surgical procedure prompted the desire to study patient outcomes and evaluate the effectiveness of this technique. The parallel advances in computer software and database technology led to the development of a registry to track patient outcomes at this center. The purpose of this study was to describe the registry's evolution and to evaluate its usefulness. Methods A team was created to develop a software database and tracking system to organize and retain information on the usage of GKS. All patients undergoing GKS were systematically entered into this database by a clinician familiar with the technology and the clinical indications. Information included patient demographics and diagnosis as well as the anatomical site of the target and details of the procedure. Results There are currently 11,738 patients in the database, which began to be used in August 1987. The University of Pittsburgh Medical Center has pioneered the evaluation and publication of the GKS technique and outcomes. Data derived from this computer database have facilitated the publication of more than 400 peer-reviewed manuscripts, more than 200 book chapters, 8 books, and more than 300 published abstracts and scientific presentations. The use of GKS has become a well-established surgical technique that has been performed more than 700,000 times around the world. Conclusions The development of a patient registry to track and analyze the use of GKS has given investigators the ability to study patient procedures and outcomes. The future of clinical medical research will rely on the ability of clinical centers to store and to share information.

Over the last two decades, stereotactic radiosurgery (SRS) has become a mainstay in the management of arteriovenous malformations (AVMs) of the brain. An extensive collective experience has demonstrated that SRS is a minimally invasive technique that can produce excellent AVM obliteration rates with only a modest risk of permanent adverse radiation effects (AREs). Controversy remains regarding the optimal treatment approach for AVMs, with much of the debate centered upon the risk:benefit ratios of microsurgical resection versus SRS. Proponents of surgery suggest that for appropriate Spetzler-Martin grade AVMs microsurgery harbors minimal morbidity and immediate cure. In contrast, supporters of SRS argue that many AVMs cannot be treated by microsurgery with limited morbidity, and that despite the possibility of hemorrhage during the latency to obliteration, the risk profile of SRS is more favorable. Unfortunately, a randomized clinic trial comparing microsurgery and SRS is not likely, so clinicians and patients must use available data to make their own decisions. Much effort has been expended to identify factors associated with AREs, defining their impact and predicting which patients are likely to have complete AVM obliteration in the absence of new neurological deficits. Refinement in an AVM management algorithm on these bases should better educate clinicians and patients about risk profiles, improve patient selection for different treatment strategies, and increase the likelihood of good therapeutic outcomes. Herein, we give a definition to the term ARE and review the suspected mechanisms that lead to them.