Long-term Outcomes of Sacral Nerve Stimulation on the Treatment of Fecal Incontinence: A Systematic Review.

INTRODUCTION: Sacral nerve stimulation (SNS) has now been used as a treatment for fecal incontinence (FI) for >20 years. The aim of this systematic review was to determine the long-term efficacy of SNS on the treatment of FI. MATERIALS AND METHODS: A comprehensive search of the MEDLINE, Embase, and Cochrane Central data bases was performed to find publications, excluding case reports, reporting outcomes of SNS treatment for FI in adults with ≥36 months of follow-up. Bias was assessed using the Risk of Bias in Non-randomized Studies-of Interventions tool. Data were summarized per reported FI-related outcomes for symptom severity and quality of life. RESULTS: In total, 3326 publications were identified, and 36 studies containing 3770 subjects were included. All studies had a serious risk of bias. Success was variably defined by each publication and ranged from 59.4% to 87.5% for per-protocol analyses and 20.9% to 87.5% for intention-to-treat analyses. All studies reporting bowel diary data, St Mark's scores, and Cleveland Clinic Incontinence Scores indicated significant improvement with SNS treatment in the long term. Studies that evaluated quality-of-life outcomes also all showed improvements in quality of life as measured by the Fecal Incontinence Quality of Life Scale. The aggregate revision rate was 35.2%, and the explantation rate was 19.7%. CONCLUSIONS: Improvements in objective and subjective outcomes at ≥36 months support using SNS for the long-term treatment of FI. Interpretation of these data is limited by a lack of comparative trials and heterogeneity of the included studies.

Compensating for Soft-Tissue Artifact Using the Orientation of Distal Limb Segments During Electromagnetic Motion Capture of the Upper Limb.

Most motion capture measurements suffer from soft-tissue artifacts (STA). Especially affected are rotations about the long axis of a limb segment, such as humeral internal-external rotation (HIER) and forearm pronation-supination (FPS). Unfortunately, most existing methods to compensate for STA were designed for optoelectronic motion capture systems. We present and evaluate an STA compensation method that (1) compensates for STA in HIER and/or FPS, (2) is developed specifically for electromagnetic motion capture systems, and (3) does not require additional calibration or data. To compensate for STA, calculation of HIER angles relies on forearm orientation, and calculation of FPS angles rely on hand orientation. To test this approach, we recorded whole-arm movement data from eight subjects and compared their joint angle trajectories calculated according to progressive levels of STA compensation. Compensated HIER and FPS angles were significantly larger than uncompensated angles. Although the effect of STA compensation on other joint angles (besides HIER and FPS) was usually modest, significant effects were seen in certain degrees-of-freedom under some conditions. Overall, the method functioned as intended during most of the range of motion of the upper limb, but it becomes unstable in extreme elbow extension and extreme wrist flexion-extension. Specifically, this method is not recommended for movements within 20 deg of full elbow extension, full wrist flexion, or full wrist extension. Since this method does not require additional calibration of data, it can be applied retroactively to data collected without the intent to compensate for STA.

Tracking Joint Angles During Whole-Arm Movements Using Electromagnetic Sensors.

Electromagnetic (EM) motion tracking systems are suitable for many research and clinical applications, including in vivo measurements of whole-arm movements. Unfortunately, the methodology for in vivo measurements of whole-arm movements using EM sensors is not well described in the literature, making it difficult to perform new measurements and all but impossible to make meaningful comparisons between studies. The recommendations of the International Society of Biomechanics (ISB) have provided a great service, but by necessity they do not provide clear guidance or standardization on all required steps. The goal of this paper was to provide a comprehensive methodology for using EM sensors to measure whole-arm movements in vivo. We selected methodological details from past studies that were compatible with the ISB recommendations and suitable for measuring whole-arm movements using EM sensors, filling in gaps with recommendations from our own past experiments. The presented methodology includes recommendations for defining coordinate systems (CSs) and joint angles, placing sensors, performing sensor-to-body calibration, calculating rotation matrices from sensor data, and extracting unique joint angles from rotation matrices. We present this process, including all equations, for both the right and left upper limbs, models with nine or seven degrees-of-freedom (DOF), and two different calibration methods. Providing a detailed methodology for the entire process in one location promotes replicability of studies by allowing researchers to clearly define their experimental methods. It is hoped that this paper will simplify new investigations of whole-arm movement using EM sensors and facilitate comparison between studies.