After surgeries for rectal cancer, surgeons in Germany have found that electronically stimulating and monitoring pelvic autonomic nerves could help in preserving body functions.
After a successful research trial in laboratory pigs, the approach has yielded promising preliminary results in a limited number of human patients during operations to remove tumors from the lower rectum, according to lead investigator Werner Kneist, MD, at Johannes Gutenberg University in Mainz, Germany. More than 140,000 new cases of colorectal cancer are diagnosed annually in the United States, according to the American Society of Colon and Rectal Surgeons.
When operating to remove tumors from the lower rectum, a procedure known as low anterior rectal resection, colorectal surgeons use so-called nerve-preserving total mesorectal excision. This approach avoids injuring pelvic autonomic nerves that control the reproductive system, bladder, and internal anal sphincter. However, even with these methods, the dysfunction rates can be surprisingly high, occurring in up to 30 to 40 percent of patients. "This [occurrence] necessitates refinements of the nerve-sparing surgical techniques," explained Daniel Kauff, MD, one of the investigators.
Dr. Kneist''s team in Mainz has used bipolar micro-fork probes to stimulate pelvic autonomic nerves intermittently and monitor their functionality during the operation. They adapted a nerve-monitoring system that then could simultaneously monitor internal anal sphincter and bladder innervation with pelvic autonomic nerve stimulation. "Nerve stimulation during the operation with observation of the internal anal sphincter and simultaneous observation of bladder manometry represents a novel method for identification and verification of pelvic autonomic nerve function," Dr. Kauff said. Manometry measures the pressure of gasses and vapors in an organ, such as the bladder in this case, or body cavity.
The investigators measured the following functions in patients before the operation and again 10 days afterward to assess urogenital and anorectal function: residual urine volume, bladder function, erectile function, incontinence scores, and bowel function. Patients in the study will receive follow-up at three-, six-, and 12-month intervals after the operation.
The investigators'' next step is to continue to enroll patients in the clinical trial and to use a more sophisticated newly developed tripolar surface electrode to stimulate the nerves continuously during the operation, Dr. Kauff said.
Along with Drs. Kneist and Kauff, coinvestigators were Oliver Kempski, Prof., Dr.; Karin H. Somerlik, Mrs.; Klaus P. Koch, Prof., Dr.-Ing.; Thorsten GĂ¶ttsche, Dipl.-Ing.; Ernst Feurer, Dr., sc., PhD; Klaus P. Hoffmann, Prof., Dr.-Ing.; and Hauke Lang, Prof., Dr., MA, FACS.
The project is funded by the Germany Ministry of Education and Research.