Clinical use of indocyanine green during nerve-sparing surgery for deep endometriosis

Objective To describe the anatomic and technical highlights of a novel nerve-sparing surgery in deep endometriosis (DE) using near-infrared (NIR) fluorescence technology and indocyanine green (ICG). Design Stepwise demonstration of this method with narrated video footage. Setting An urban general hospital. Patient(s) A 48-year-old woman was referred for severe chronic pelvic pain, dysmenorrhea, and pain on defecation, all of which were resistant to medication therapy. Magnetic resonance imaging revealed uterine adenomyosis and left ovarian endometrioma with DE involving the uterosacral ligament, posterior cervix, and surface of the rectum, with complete cul-de-sac obliteration. Intervention(s) An intravenous injection of 0.25 mg/kg body weight of ICG for intraoperative NIR fluorescence imaging. Ethics approval was obtained from the institutional review board at our hospital (IRB No.: 985). Main Outcome Measure(s) Evaluation of blood perfusion of DE nodule and achieving better visualization of anatomic relationship to the pelvic autonomic nerves. Result(s) The procedure was performed using the following eight steps with the da Vinci Xi surgical platform: Step 0, observing peritoneal endometriotic lesions; Step 1, adhesiolysis and adnexal surgery; Step 2, separation of the nerve plane; Step 3, dissection of the ureter; Step 4, reopening of the pouch of Douglas; Step 5, complete removal of DE lesions while avoiding injury to the nerve plane; Step 6, hysterectomy (if the patient desires nonfertility-sparing surgery); Step 7, checking for rectal injury using air leakage test and tissue perfusion; and Step 8, barrier agents for adhesion prevention. During surgery, we could easily identify ischemic nodules, which included DE and fibrosis under NIR fluorescence imaging, beyond the limits of macroscopic disease. Endometriosis or fibrosis was confirmed pathologically from all resected tissues, and resection margins of these tissues were negative for the disease. These results suggest that this technique might be feasible for objectively identifying the border between DE lesions and healthy tissue. Furthermore, the hypogastric nerve and inferior hypogastric plexus were strongly highlighted by ICG and objectively preserved with the assessment of perfusion. The patient developed no perioperative complications, including postoperative bladder or rectal dysfunction after surgery. Conclusion(s) To our knowledge, this is the first reported use of ICG during nerve-sparing surgery for gynecologic disease. Application of ICG with NIR fluorescence appears potentially useful, not only to remove DE, but also to improve nerve-sparing.