Radical resection of deep infiltrating endometriosis (DIE) or pelvic malignancies can lead to inadvertent damage to the pelvic autonomic nerve bundles, causing urinary dysfunction in up to 41% of cases, as well as anorectal and sexual dysfunction.1 Each of these sequelae can significantly affect the patient’s quality of life.
Nerve-sparing techniques have therefore been a trending topic in gynecologic surgery in the 21st century, starting with papers by Marc Possover, MD, of Switzerland, on the laparoscopic neuronavigation (LANN) technique. In an important 2005 publication, he described how the LANN technique can significantly reduce postoperative functional morbidity in laparoscopic radical pelvic surgery.2
The LANN method utilizes intraoperative neurostimulation to identify and dissect the intrapelvic nerve bundles away from surrounding tissue prior to dissection of the DIE or pelvic malignancies. The nerves are exposed and preserved under direct visualization in a fashion similar to that used to expose and preserve the ureters. Pelvic dissection using the LANN technique is extensive and occurs down to the level of the sacral nerve roots.
Dr. Possover’s 2005 paper and others like it spurred increased awareness of the intrapelvic part of the autonomic nervous system – in particular, the hypogastric nerves, the pelvic splanchnic nerves, and the inferior hypogastric plexus. Across additional published studies, nerve-sparing techniques were shown to be effective in preserving neurologic pelvic functions, with significantly less urinary retention and rectal/sexual dysfunction than seen with traditional laparoscopy techniques.
For example, in a single-center prospective clinical trial reported in 2012, 56 of 65 (86.2%) patients treated with a classical laparoscopic technique for excision of DIE reported neurologic pelvic dysfunctions, compared with 1 of 61 (1.6%) patients treated with a nerve-sparing approach.3
While research has confirmed the importance of nerve-sparing techniques, it also shone light on the reality that the LANN technique is extremely technically challenging and requires a high level of surgical expertise and advanced training. In my teaching of the technique, I also saw that few gynecologic surgeons were able to incorporate the advanced nerve-sparing technique into their practices.
A group consisting of myself and collaborators at the University of Bologna, Italy, and the University of Cambridge, England, recently developed an alternative to the LANN approach that uses the hypogastric nerves as landmarks. The technique requires less dissection and should be technically achievable when the pelvic neuroanatomy and anatomy of the presacral fascia are well understood. The hypogastric nerve is identified and used as a landmark to preserve the deeper autonomic nerve bundles in the pelvis without exposure and without more extensive dissection to the level of the sacral nerve roots.4,5
This hypogastric nerve-based technique will cover the vast majority of radical surgeries for DIE. When more advanced nerve sparing and more extensive dissection is needed for the very deepest levels of disease infiltration, patients can be referred to surgeons with advanced training, comfort, and experience with the LANN technique.