Impact of cervical full-endoscopic spine surgery on intracranial pressure in swine.

INTRODUCTION: Cervical full-endoscopic spine surgery (FESS) has grown in clinical use, but the effects of irrigation on intracranial pressure (ICP) remain poorly understood and may pose neurological risks. RESEARCH QUESTION: Whether cervical FESS induces relevant ICP increases compared with prior lumbar data, under different irrigation parameters, drainage occlusion states, and anesthesia depths. MATERIAL AND METHODS: In a controlled swine model, four female Sus scrofa domesticus (50-75 kg) underwent cervical FESS with a uniportal, dual-channel suction-irrigation endoscope under total intravenous anesthesia. ICP was monitored invasively via intraparenchymal catheter. Irrigation pump settings were tested in graded configurations with drainage outflow open, partially occluded, or totally occluded. Anesthesia depth was modulated to assess its influence on ICP dynamics. RESULTS: Baseline ICP averaged 11.1 mmHg. Cervical FESS produced marked ICP increases, particularly during partial and total drainage obstruction, with peaks up to 102 mmHg. Under open drainage, ICP ranged from 7.9 to 29.1 mmHg, occasionally exceeding the 20 mmHg safety threshold but remaining lower than during occlusion. With anesthesia-depth modulation, mild sedation yielded occlusion peaks up to 62.5 mmHg, whereas deeper anesthesia was associated with open-drainage ICP of 9.5-19.7 mmHg and occlusion peaks of 23-36.6 mmHg. DISCUSSION AND CONCLUSION: Cervical FESS was associated with earlier and more pronounced ICP elevations than lumbar procedures. Saline outflow occlusion is the primary trigger of critical pressure surges, while pump parameters modulate magnitude. Deeper anesthesia was associated with attenuated ICP responses. Maintaining drainage patency, using the lowest effective pump settings, and appropriate anesthetic management may reduce the risk of critical intracranial hypertension.