Ultrasonographic evaluation of intraoperative optic nerve sheath diameter changes in patients undergoing laparoscopic surgery

Laparoscopic surgery offers several advantages such as reduced postoperative pain and faster recovery; however, the establishment of pneumoperitoneum has the potential to transiently increase intracranial pressure (ICP). Ultrasonographic measurement of the optic nerve sheath diameter (ONSD) provides a reliable noninvasive indicator of ICP changes. This study aimed to evaluate ONSD measurements, which may reflect intraoperative ICP changes during laparoscopic upper abdominal surgery performed in the reverse Trendelenburg position, and to assess the specific effects of pneumoperitoneum. Fifty-five patients with ASA physical status I-III who undergoing elective laparoscopic upper abdominal surgery were prospectively enrolled. Bilateral ONSD measurements were performed at four time points: after induction of anesthesia (T0), 10 min (T1), and 60 min (T2) after the establishment of pneumoperitoneum, and 10 min after desufflation (T3). Respiratory and hemodynamic parameters were recorded simultaneously. Mean ONSD values increased significantly at both 10 and 60 min of pneumoperitoneum compared to baseline (p < 0.001) and remained elevated even after desufflation (p < 0.01). No significant difference was observed between T1 and T2. Peak and plateau pressures increased while compliance decreased during pneumoperitoneum (p < 0.001). Pneumoperitoneum during laparoscopic upper abdominal surgery causes a significant yet transient increase in ONSD. Although ONSD values showed a partial decrease after desufflation, they remained higher than baseline measurements but within clinically acceptable and non-critical ranges. Continuous intraoperative ultrasonographic ONSD monitoring may provide real-time insight into intracranial dynamics, particularly in patients at risk for elevated ICP. Further studies are warranted to clarify the underlying multifactorial mechanisms and determine the clinical significance of ONSD alterations. NCT06209034, Registered January 6, 2024. (Retrospectively registered). GOKAEK-2023/19.12.