Preoperative Acetazolamide Challenge in Pediatric Chiari I Malformation.

PURPOSE: In patients who present with headaches and Chiari 1 malformation without cranial nerve or brainstem dysfunction or syrinx formation, the decision to decompress can be difficult to make. We present a case series examining the use of acetazolamide as a diagnostic aid to determine candidacy for decompression. METHODS: A single pediatric neurosurgeon's (M.M.H.) experience from 2003 to 2018 was retrospectively reviewed. All cases evaluated in the clinic for CPT code of Chiari 1 malformation were analyzed. Inclusion criteria were patients with diagnosis of Chiari 1 malformation and headache-predominant symptoms who underwent an acetazolamide challenge test. Exclusion criteria included age over 18, syrinx, or significant clinical evidence of brainstem compression or cranial nerve dysfunction. Data were recorded with respect to response to acetazolamide. Surgical outcomes were assessed using the Chicago Chiari Outcome Scale (CCOS) pain category and the improve/same/worse (IWS) scale. Overall satisfaction from surgery was also recorded. RESULTS: Forty-five patients met inclusion criteria and underwent acetazolamide challenge. Thirty-three (73.3%) patients showed improvement of their symptoms with acetazolamide challenge (responders). Of the 33 responders, 25 (75.8%) underwent Chiari decompression. The remaining 8 (24.2%) responders experienced persistent improvement of their symptoms after the acetazolamide trial and did not require intervention. Twelve (26.7%) patients did not improve with acetazolamide (nonresponders) of which 11 (91.7% of nonreponders) never required intervention. One nonresponder eventually underwent Chiari decompression due to progressively worsening and debilitating headaches. All twenty-five (100%) responders improved after surgery and 24 (96%) were satisfied with the outcome of surgery. The average responder CCOS pain score was 3.52 out of 4. The nonresponder who did not improve with acetazolamide had persistent severe headaches after decompression. The CCOS pain score for this nonresponder was 2 out of 4. CONCLUSION: Pediatric headache-predominant Chiari 1 malformation presents a difficult diagnostic dilemma. The authors describe a trial of acetazolamide as a preoperative diagnostic tool to aid the decision to decompress. Further studies will need to be performed to determine the effectiveness of preoperative acetazolamide in identifying which patients may benefit from surgical decompression.

Endoscopic Third Ventriculostomy and Endoscopic Intracranial Cyst Fenestration in an Outpatient Ambulatory Surgery Center Yields Reduced Cost But Equal Efficacy and Safety Compared with Surgery in the Hospital.

BACKGROUND: A transition is underway in neurosurgery to perform relatively safe surgeries outpatient, often at ambulatory surgery centers (ASC). We sought to evaluate whether simple intracranial endoscopic procedures such as third ventriculostomy and cyst fenestration can be safely and effectively performed at an ASC, while comparing costs with the hospital. METHODS: A retrospective chart review was performed for patients who underwent elective intracranial neuroendoscopic (NE) intervention at either a quaternary hospital or an affiliated ASC between August 2014 and September 2017. Groups were compared on length of stay, perioperative and 30-day morbidity, as well as clinical outcome at last follow-up. The total cost for these procedures were compared in relative units between all ASC cases and a small subset of hospital cases. RESULTS: In total, 16 NE operations performed at the ASC (mean patient age 29.8 years) and 37 at the hospital (mean age 15.4 years) with average length of stay of 3.5 hours and 23.1 hours respectively (P < 0.05). There were no acute complications in either cohort or morbid events requiring hospitalization within 30 days. Surgical success was noted for 75% of the ASC patients and 73% of the hospital cohort. The mean cost of 5 randomly selected hospital operations with same-day discharge and 5 with overnight stay was 3.4 and 4.1 times that of the ASC cohort, respectively (P < 0.05). CONCLUSIONS: Elective endoscopic third ventriculostomy and other simple NE procedures can be safely and effectively performed at an ASC for appropriate patients with significantly reduced cost compared with the hospital.