Faculty Bibliography

Background: Surgical resection of pituitary adenomas is associated with a 10 to 30% rate of temporary diabetes insipidus with ~50% resolving within 1 week and 80% resolving at 3 months.[1] Adrenal insufficiency occurs in ~ 5 % of patients and can result in an Addisonian crisis if left undiagnosed postoperatively.[1] [2] Many studies have been performed looking at readmission rates after pituitary surgery. A review of over 1,200 cases demonstrated a readmission rate of 8.5% with the most common cause being hyponatremia (29.5%).[3] To reduce the rate of readmission for hyponatremia, some groups have demonstrated the effective use of outpatient fluid restriction criteria during the first week post-op.[4] These guidelines are intended for the management of standard postoperative hormonal fluctuations which do not necessitate endocrine consultation during hospitalization.
Objective(s): Retrospectively evaluate patients undergoing endoscopic endonasal resection of pituitary adenomas to identify areas for quality improvement through the development of more standardized postoperative guidelines.
Method(s): A retrospective review of 75 patients who underwent endoscopic endonasal resection of pituitary adenomas at a single academic center from 2013 to 2018. We evaluated the average length of stay, number of laboratory studies performed, need for hormone supplementation long term and short term, rate of gross-total resection, rate of cerebrospinal fluid leak, rate of infection, and 30-day readmission rate ([Table 1]). From this, we have developed a change in guidelines aimed at reducing length of stay, redundant laboratory studies, and reduced rate of readmission.
Conclusion(s): Although our current outcomes for resection of pituitary adenoma are on par with published data, we have identified areas of possible quality improvement which have since been implemented

BACKGROUND:A major concern of patients who have stereotactic radiosurgery is the long-term risk of having a secondary intracranial malignancy or, in the case of patients with benign tumours treated with the technique, the risk of malignant transformation. The incidence of stereotactic radiosurgery-associated intracranial malignancy remains unknown; therefore, our aim was to estimate it in a population-based study to assess the long-term safety of this technique. METHODS:We did a population-based, multicentre, cohort study at five international radiosurgery centres (Na Homolce Hospital, Prague, Czech Republic [n=2655 patients]; Ruber International Hospital, Madrid, Spain [n=1080], University of Pittsburgh Medical Center, Pittsburgh, PA, USA [n=1027]; University of Virginia, Charlottesville, VA, USA [n=80]; and NYU Langone Health System, New York, NY, USA [n=63]). Eligible patients were of any age, and had Gamma Knife radiosurgery for arteriovenous malformation, trigeminal neuralgia, or benign intracranial tumours, which included vestibular or other benign schwannomas, WHO grade 1 meningiomas, pituitary adenomas, and haemangioblastoma. Patients were excluded if they had previously had radiotherapy or did not have a minimum follow-up time of 5 years. The primary objective of the study was to estimate the incidence of stereotactic radiosurgery-associated intracranial malignancy, including malignant transformation of a benign lesion or development of radiation-associated secondary intracranial cancer, defined as within the 2 Gy isodose line. Estimates of age-adjusted incidence of primary CNS malignancies in the USA and European countries were retrieved from the Central Brain Tumor Registry of the United States (CBTRUS) and the International Agency for Research on Cancer (IARC) Global Cancer statistics. FINDINGS/RESULTS:Of 14 168 patients who had Gamma Knife stereotactic radiosurgery between Aug 14, 1987, and Dec 31, 2011, in the five contributing centres, 4905 patients were eligible for the analysis (had a minimum follow-up of 5 years and no history of previous radiation therapy). Diagnostic entities included vestibular schwannomas (1011 [20·6%] of 4905 patients), meningiomas (1490 [30·4%]), arteriovenous malformations (1089 [22·2%]), trigeminal neuralgia (565 [11·5%]), pituitary adenomas (641 [13·1%]), haemangioblastoma (29 [0·6%]), and other schwannomas (80 [1·6%]). With a median follow-up of 8·1 years (IQR 6·0-10·6), two (0·0006%) of 3251 patients with benign tumours were diagnosed with suspected malignant transformation and one (0·0002%) of 4905 patients was considered a case of radiosurgery-associated intracranial malignancy, resulting in an incidence of 6·87 per 100 000 patient-years (95% CI 1·15-22·71) for malignant transformation and 2·26 per 100 000 patient-years (0·11-11·17) for radiosurgery-associated intracranial malignancy. Two (0·0004%) of 4905 patients developed intracranial malignancies, which were judged unrelated to the radiation field. Overall incidence of radiosurgery-associated malignancy was 6·80 per 100 000 patients-years (95% CI 1·73-18·50), or a cumulative incidence of 0·00045% over 10 years (95% CI 0·00-0·0034). The overall incidence of 6·8 per 100 000, which includes institutions from Europe and the USA, after stereotactic radiosurgery was found to be similar to the risk of developing a malignant CNS tumour in the general population of the USA and some European countries as estimated by the CBTRUS and IARC data, respectively. INTERPRETATION/CONCLUSIONS:These data show that the estimated risk of an intracranial secondary malignancy or malignant transformation of a benign tumour in patients treated with stereotactic radiosurgery remains low at long-term follow-up, and is similar to the risk of the general population to have a primary CNS tumour. Although prospective cohort studies with longer follow-up are warranted to support the results of this study, the available evidence suggests the long-term safety of stereotactic radiosurgery and could support physicians counselling patients on Gamma Knife stereotactic radiosurgery. FUNDING/BACKGROUND:None.

OBJECTIVE:Given rising scrutiny of healthcare expenditures, understanding intervention costs is increasingly important. This study aimed to compare and characterize costs for vestibular schwannoma (VS) management with microsurgery and radiosurgery to inform practice decisions and appraise cost reduction strategies. METHODS:In conjunction with medical records, internal hospital financial data were used to evaluate costs. Total cost was divided into index costs (costs from arrival through discharge for initial intervention) and follow-up costs (through 36 months) for 317 patients with unilateral VSs undergoing initial management between June 2011 and December 2015. A retrospective matched cohort based on tumor size with 176 patients (88 undergoing each intervention) was created to objectively compare costs between microsurgery and radiosurgery. The full sample of 203 patients treated with resection and 114 patients who underwent radiosurgery was used to evaluate a broad range of outcomes and identify cost contributors within each intervention group. RESULTS:Within the matched cohort, average index costs were significantly higher for microsurgery (100% by definition, because costs are presented as a percentage of the average index cost for the matched microsurgery group; 95% CI 93-107) compared to radiosurgery (38%, 95% CI 38-39). Microsurgery had higher average follow-up costs (1.6% per month, 95% CI 0.8%-2.4%) compared to radiosurgery (0.5% per month, 95% CI 0.4%-0.7%), largely due to costs incurred in the initial months after resection. A major contributor to total cost and cost variability for both resection and radiosurgery was the need for additional interventions in the follow-up period, which were necessary due to complications or persistent functional deficits. Although tumor size was not associated with increased total costs for radiosurgery, linear regression analysis demonstrated that, for patients who underwent microsurgery, each centimeter increase in tumor maximum diameter resulted in an estimated increase in total cost of 50.2% of the average index cost of microsurgery (95% CI 34.6%-65.7%) (p < 0.001, R2 = 0.17). There were no cost differences associated with the proportion of inpatient days in the ICU or with specific surgical approach for patients who underwent resection. CONCLUSIONS:This study is the largest assessment to date based on internal cost data comparing VS management with microsurgery and radiosurgery. Both index and follow-up costs are significantly higher when tumors were managed with resection compared to radiosurgery. Larger tumors were associated with increased resection costs, highlighting the incremental costs associated with observation as the initial management.