Intraoperative optic nerve sheath diameter changes in vNOTES versus total laparoscopic hysterectomy: a prospective randomized study.

BACKGROUND

Pneumoperitoneum and steep Trendelenburg positioning during laparoscopic hysterectomy may increase intracranial pressure. Optic nerve sheath diameter (ONSD), measured by transorbital ultrasonography, is a validated noninvasive surrogate of intracranial pressure. Vaginal natural orifice transluminal endoscopic surgery (vNOTES) has been proposed as a less invasive alternative to total laparoscopic hysterectomy (TLH), potentially requiring lower intra-abdominal pressure and less steep Trendelenburg positioning. However, comparative data regarding their intraoperative effects on ONSD remain limited.

METHODS

This prospective randomized trial included 66 patients undergoing elective hysterectomy, allocated to either vNOTES (n = 33) or TLH (n = 33). ONSD was measured bilaterally at predefined intraoperative time points using transorbital ultrasonography. Longitudinal changes were analyzed using linear mixed-effects models. Postoperative nausea, vomiting, and neurological symptoms were assessed during the first 24 h postoperatively.

RESULTS

Baseline ONSD values were comparable between groups. A significant effect of time on ONSD (P < 0.001) and a significant group × time interaction (P < 0.001) were observed, indicating distinct intraoperative ONSD trajectories. Compared with vNOTES, TLH was associated with greater increases in ONSD at 30 min after pneumoperitoneum (estimated mean difference - 0.14 mm, 95% CI - 0.19 to - 0.09) and at the end of surgery after desufflation (estimated mean difference - 0.19 mm, 95% CI - 0.27 to - 0.11). Postoperative nausea and vomiting occurred more frequently in the TLH group; however, this difference did not reach statistical significance (54.5 vs. 36.4%, P = 0.138) and should be interpreted cautiously.

CONCLUSIONS

Total laparoscopic hysterectomy was associated with more pronounced intraoperative increases in ONSD compared with vNOTES, likely reflecting surgical and positional factors. Although postoperative outcomes were statistically similar, the observed difference in PONV should be interpreted cautiously and did not demonstrate a statistically significant reduction.