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Bilateral measurement of pelvic floor muscle dysfunction in females with lower urinary tract symptoms using near infrared spectroscopy

University of British Columbia

Introduction and Objective: Near infrared spectroscopy (NIRS) is a noninvasive method of measuring oxygen recovery kinetics in skeletal muscle. NIRS detects changes in oxygenated (O₂Hb) and deoxygenated (HHb) hemoglobin in response to exercise, to provide interpretation of muscular capacity to restore incurred oxygen debt. Assessment of pelvic floor muscle (PFM) function is central to managing urinary incontinence (UI) and lower urinary tract symptoms (LUTS) but currently lacks oxygen kinetic parameters. This project aims to develop a NIRS probe that measures oxygen kinetics of bilateral PFM in females with UI/LUTS (cases) related to altered pelvic innervation compared to continent controls. Methods: A transvaginal NIRS prototype to detect bilateral PFM was developed. The vaginal NIRS probe monitored female volunteers during sustained PFM contraction (SMVC). O₂Hb, HHb and HbDiff (O₂Hb-HHb) allowed measurement of oxygen kinetics unique to bilateral PFM. Oxygen recovery kinetics determined by HbDiff half recovery time (½RT). PFM manometry assessed SMVC peak and average cmH₂O. Home-based 8-week PFM therapy (PFMT) intervention was performed by both participant groups and an exercise diary measured adherence, determined as total percentage of volume and frequency. Results: Observational NIRS findings demonstrated typical hemodynamic and ½RT responses in controls. Case group demonstrated atypical findings consistent with impaired muscle function. NIRS found quicker ½RT for controls (7.87 vs 38.03 seconds, p 0.01). Manometer detected greater PFM strength and endurance in controls (SMVC peak 35 vs 13 cmH2O, p <0.01, SMVC average 23 vs 10 cmH₂O, p 0.02). Intra-group improvements of PFM NIRS and manometer variables after PFMT were not determined. Post-PFMT ½RT in cases was highly correlated to SMVC peak and average cmH2O (r -0.83 and r -0.82, respectively). High adherence of PFMT frequency demonstrated in cases, 78%, which correlated to SMVC peak and average cmH₂O (rs 0.78 and rs 0.88, respectively), ½RT (rs -0.85) and reduced urgency (rs -0.85). Conclusions: This study shows the feasibility of NIRS to provide novel physiologic data regarding PFM function. PFM oxygen kinetics could provide more insight into PFM pathology and PFMT rehabilitation. Further refinement of the NIRS probe is required for use in larger studies with PFMT interventions incorporating adjunctive therapies.

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2019-03-20

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/68995

Experimental Medicine

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/