01/26/2026
Urinary, f***l, or sexual disorders in robotic re**al surgery can occur with surgical injury of the pelvic nerves. Monitoring with tissue impedance measurements is a novel technology in the space.
It's monitoring the autonomic nerves through stimulation.
First off, where might this be beneficial? From the paper cited below:
"Pelvic neuromonitoring can be performed with known standard neuromonitoring methods such as transcranial motor evoked potentials (tcMEP) from the external urethral sphincter (EUS) and external a**l sphincter (EAS), free-running and triggered EMG from the EUS and EAS, as well as bulbocavernosus reflex (BCR) measurement and pudendal somatosensory evoked potentials (SSEPs). All of these methods monitor afferent and efferent fibers of the pudendal nerve that innervate the motor sphincter muscles in the pelvic floor, which is mandatory in sacral spinal procedures. Functional control and identification of pelvic autonomic nerves are not covered, which is essential during low anterior resections."
Needles were placed intraoperatively into the bladder and re**um. The paper notes some unexpected difficulties in solutions when dealing with space-occupying lesions and proper needle placement.
Catheter electrodes in the urethral sphincter and re**al probe in the a**l ca**l were used to compare the impedance of the tissue layer between these electrodes and the needles placed.
Continuous monitoring + intermittent mapping for selective localization of the hypogastric plexus was used.
Interpretation of a positive response:
(a)
new onset of change in the impedance signal after application of direct nerve stimulation
(b)
similarity of the signal waveform and morphology with the impedance signals derived in the animal study
(c)
duration of the impedance change of several seconds, correlating with the duration of a slow smooth muscle contraction after evocation of spikes (3–15/min)1
(d)
confirmation of the positive signal response by a negative control in the surrounding tissue, where no nerves are expected
A negative signal response was considered as no change in the impedance signal after the application of direct stimulation to a control tissue portion.
Results
Seems they had a consistent ability to stimulate and record with noted preservation or minimizing surgical effects.
As noted in the paper, more time to assess the outcomes and a larger sample size would help determine true outcome differences.
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Overall, a good paper to read to:
1) Stay up to date on what's coming around the corner
2) Beef up on your understanding of filter settings and potential difficulties that can arise during surgery
Schuler, R., Marquardt, C., Kalev, G., Langer, A., Konschake, M., Schiedeck, T., ... & Goos, M. (2023). Technical aspects of a new approach to intraoperative pelvic neuromonitoring during robotic re**al surgery. Scientific Reports, 13(1), 17156.