A Novel High-Density Electromyography Probe for Evaluating Anorectal Neurophysiology: Design, Human Feasibility Study, and Validation with Trans-Sacral Magnetic Stimulation

Experimental evaluation of an artificial anal sphincter based on biomechanical compatibility

BACKGROUND

The artificial anal sphincter is a device used to treat patients with fecal incontinence who are unable to control their bowel movements on their own. Long-term morphological changes in the tissue surrounding the artificial anal sphincter can cause biomechanical compatibility problems, which seriously affect the clinical application of the artificial anal sphincter.

METHODS

In this paper, the superelasticity of shape memory alloys was utilized to design and fabricate a biomechanically compatible constant force clamping artificial anal sphincter. An in vitro simulation system was constructed to verify the effectiveness, safety, and constant force characteristics of the artificial anal sphincter.

RESULTS

The experimental results demonstrated that the artificial anal sphincter could be effectively closed with no leakage of the liquid-like intestinal contents, which are most likely to leak. The pressure of the artificial anal sphincter on the intestinal tube gradually increased and eventually became constant during closure, and the pressure value was always less than the intestinal blood supply pressure threshold.

CONCLUSIONS

In this paper, we designed an artificial anal sphincter based on biomechanical compatibility and the corresponding in vitro simulation experimental program and preliminarily verified the effectiveness, safety, and constant force characteristics of the artificial anal sphincter.

Image Segmentation for High-Density Surface Electromyography Mappings of Pelvic Floor Muscle Activity of Women with Interstitial Cystitis/Bladder Pain Syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) can result in pelvic floor muscle (PFM) overactivity. Current clinical assessment protocols include basic electromyographic assessment of PFM activation; however, they do not provide a comprehensive assessment localized to each region of the PFM. We examined the ability of high-definition features from intravaginal high-density surface electromyography (HD-sEMG) to assess the severity of PFM overactivity in female IC/BPS patients. HD-sEMG was collected from fifteen female IC/BPS patients and fifteen urologically healthy female controls. The 2D mappings of root mean squared amplitude (RMS) at rest normalized by maximal voluntary contraction (resting RMS ratios) were segmented via k-means to identify areas of peak activity and surrounding activity. Female IC/BPS patients exhibited significantly greater resting RMS ratios for peak activity (p=0.0096), surrounding activity (p=0.0003), and average activity (p=0.0016) compared to healthy female controls. Furthermore, the area of peak activity was significantly larger for female IC/BPS patients than for healthy female controls (p=0.0063). Image segmentation of intravaginal HD-sEMG provides a more robust biomarker of PFM as compared to current methods.

Intraoperative serosal extracellular mapping of the human distal colon: a feasibility study

BACKGROUND

Cyclic motor patterns (CMP) are the predominant motor pattern in the distal colon, and are important in both health and disease. Their origin, mechanism and relation to bioelectrical slow-waves remain incompletely understood. During abdominal surgery, an increase in the CMP occurs in the distal colon. This study aimed to evaluate the feasibility of detecting propagating slow waves and spike waves in the distal human colon through intraoperative, high-resolution (HR), serosal electrical mapping.

METHODS

HR electrical recordings were obtained from the distal colon using validated flexible PCB arrays (6 × 16 electrodes; 4 mm inter-electrode spacing; 2.4 cm2, 0.3 mm diameter) for up to 15 min. Passive unipolar signals were obtained and analysed.

RESULTS

Eleven patients (33-71 years; 6 females) undergoing colorectal surgery under general anaesthesia (4 with epidurals) were recruited. After artefact removal and comprehensive manual and automated analytics, events consistent with regular propagating activity between 2 and 6 cpm were not identified in any patient. Intermittent clusters of spike-like activities lasting 10-180 s with frequencies of each cluster ranging between 24 and 42 cpm, and an average amplitude of 0.54 ± 0.37 mV were recorded.

CONCLUSIONS

Intraoperative colonic serosal mapping in humans is feasible, but unlike in the stomach and small bowel, revealed no regular propagating electrical activity. Although sporadic, synchronous spike-wave events were identifiable. Alternative techniques are required to characterise the mechanisms underlying the hyperactive CMP observed in the intra- and post-operative period.

NEW FINDINGS

The aim of this study was to assess the feasibility of detecting propagating electrical activity that may correlate to the cyclic motor pattern in the distal human colon through intraoperative, high-resolution, serosal electrical mapping. High-resolution electrical mapping of the human colon revealed no regular propagating activity, but does reveal sporadic spike-wave events. These findings indicate that further research into appropriate techniques is required to identify the mechanism of hyperactive cyclic motor pattern observed in the intra- and post-operative period in humans.

Bionic measurement of defecation in a swine model

OBJECTIVE

Fecobionics was used to assess pressures, orientation, bending, shape, and cross-sectional area (CSA) changes during defecation. This study aimed to evaluate the device feasibility and performance in swine.

APPROACH

Twelve pigs had wired or wireless Fecobionics devices inserted in the rectum. The bag was distended to simulate feces in the rectum. Fecobionics data were acquired simultaneously during the whole experiment. Six pigs were euthanized immediately after the procedure for evaluation of acute injury to anorectum (acute group). The remaining pigs lived two weeks before euthanasia for evaluation of long-term tissue damage and inflammation (chronic group). Signs of discomfort were monitored.

MAIN RESULTS

All animals tolerated the experiment well. The chronic animals showed normal behavior after the procedure. Mucosal damage, bleeding, or inflammation was not found in either group. Fecobionics was defecated 1 min 35 s-61 min 0 s (median 8 min 58 s) after insertion. The defecation lasted 0 min 20 s-4 min 25 s (median 1 min 52 s). The device was almost straight inside rectum (160°-180°) but usually bended 5°-20° during contractions. The three pressure sensors showed simultaneous and identical increase during rectal or abdominal muscle contractions, indicating the location inside rectum. During defecation, the maximum rear pressure was 114.1 ± 14.3 cmH₂O whereas the front pressure gradually decreased to 0 cmH₂O, indicating the front passed anus. CSA decreased from 1017.1 ± 191.0 mm² to 530.7 ± 46.5 mm² when the probe passed from the rectum through the anal canal.

SIGNIFICANCE

Fecobionics provides defecatory measurements under physiological conditions in pigs without inducing tissue damage.