Innovative Surgical Method Helps Preserve the Bladder

A new study claims that using microtechnology to electronically stimulate and monitor pelvic autonomic nerves may help prevent problems after a surgical procedure for rectal cancer, such as bladder, urinary, and fecal incontinence, as well as sexual function disorders.

Researchers at Johannes Gutenberg University (Mainz, Germany) used bipolar microfork probes to stimulate pelvic autonomic nerves intermittently, and monitor their functionality during the operation. To do so, they adapted a nerve-monitoring system that could simultaneously monitor internal anal sphincter and bladder innervation with pelvic autonomic nerve stimulation. The researchers also measured the pressure of gasses and vapors in the bladder via manometry--a test used to assess motor function in an organ or body cavity.

After a successful research trial in laboratory pigs, the researchers also reported promising preliminary results in a limited number of human patients during operations to remove tumors from the lower rectum. The investigators measured several functions in patients before the operation, and again 10 days afterward, to assess urogenital and anorectal functions, including residual urine volume, bladder function, erectile function, incontinence scores, and bowel function. Patients in the study will receive follow-up at 3-, 6-, and 12-month intervals after the operation. The study was presented at the annual clinical congress of the American College of Surgeons (ACS), held during October 2010, in Washington (DC, USA).

"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,” said coauthor Daniel Kauff, M.D. 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.

When operating to remove tumors from the lower rectum--a procedure known as low anterior rectal resection--colorectal surgeons use nerve-preserving total mesorectal excision to avoid injuring the pelvic autonomic nerves that control the reproductive system, bladder, and internal anal sphincter. However, even with this method, the dysfunction rates can be surprisingly high, occurring in up to 30 to 40% of patients.

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Johannes Gutenberg University