Does Intraperitoneal Washout Further Reduce Pain After Low-Pressure vNOTES Hysterectomy?

Does Intraperitoneal Washout Further Reduce Pain After Low-Pressure vNOTES Hysterectomy? Results From a Randomized Controlled Trial.

The evolution of minimally invasive gynecology has transitioned from traditional laparotomy to laparoscopy, and most recently, to vNOTES (Vaginal Natural Orifice Transluminal Endoscopic Surgery). By combining the visual advantages of endoscopy with the scarless approach of vaginal surgery, vNOTES has demonstrated superior outcomes in terms of reduced postoperative pain, shorter hospital stays, and improved cosmetic results compared to traditional total laparoscopic hysterectomy (TLH).

Despite these advancements, post-laparoscopic pain syndrome (PLPS) remains a significant clinical challenge. Characterized by deep-seated abdominal pressure and referred shoulder-tip pain, PLPS is primarily attributed to the irritation of the phrenic nerve caused by residual carbon dioxide and the formation of carbonic acid on the peritoneal surface. In the Trendelenburg position required for gynecologic procedures, this gas often becomes trapped in the subdiaphragmatic space, leading to significant distress that can delay discharge even when the surgical site itself is healing well.

The physiological impact of the pneumoperitoneum is largely pressure-dependent. The landmark study by Barczyński and Herman (2004) in general surgery established that maintaining a low-pressure pneumoperitoneum (<10 mmHg) significantly reduces peritoneal stretching and the subsequent inflammatory response. Furthermore, the technique of intraperitoneal saline washout has been proposed to physically remove residual CO2 and dilute acidic metabolites, thereby mitigating phrenic nerve irritation.

While these techniques have been validated in abdominal laparoscopic procedures such as cholecystectomy, their efficacy within the unique framework of vNOTES hysterectomy remains unexplored. vNOTES naturally utilizes lower pressures than traditional laparoscopy, yet the incidence of referred pain persists. There is currently a lack of high-level evidence determining whether the addition of a standardized saline washout provides an incremental benefit over low-pressure vNOTES alone.

The aim of this prospective, randomized controlled trial is to evaluate the impact of intraperitoneal saline washout on postoperative pain scores and analgesic consumption in patients undergoing low-pressure vNOTES hysterectomy. The investigators hypothesize that the combination of low-pressure insufflation and active saline washout will result in a synergistic reduction in post-laparoscopic pain, facilitating an ultra-fast-track recovery protocol.

Inclusion Criteria:

• Surgical Indication: Scheduled for elective total hysterectomy for gynecological conditions
• Deemed suitable candidates for the vNOTES (Vaginal Natural Orifice Transluminal Endoscopic Surgery) approach by a senior gynecologic surgeon.
• American Society of Anesthesiologists (ASA) physical status classification I or III.
• Uterine volume ≤14 weeks of gestation (or a sonographically estimated weight of ≤ 500 grams) to ensure a standardized vNOTES procedural duration
• Ability to understand the study protocol and provide written informed consent, including the willingness to use the Visual Analogue Scale (VAS) for pain assessment.
• Sufficient literacy and fluency in Turkish to accurately complete postoperative pain and recovery surveys

Exclusion Criteria:

• Chronic Pain Syndromes: Diagnosis of chronic pelvic pain, fibromyalgia, or any condition requiring long-term analgesic or opioid therapy, as these may distort postoperative Visual Analogue Scale (VAS) scores.

  • Extensive Adhesions: Known or suspected severe pelvic adhesions (Stage III or IV endometriosis) or a history of multiple major abdominal surgeries that might necessitate conversion to traditional laparoscopy or laparotomy.
  • Uterine Size: Uterine weight exceeding 500 grams or size greater than 14 weeks of gestation, potentially requiring morcellation or prolonged surgical time.
  • Anatomical Constraints: Severe vaginal stenosis or insufficient vaginal access that precludes the vNOTES approach.
  • Hypersensitivity: Known allergy or hypersensitivity to local anesthetics or medications used in the standardized postoperative pain protocol.
  • Psychiatric/Cognitive Disorders: Any condition that impairs the patient's ability to reliably report pain levels using the VAS or follow the study protocol.