A dual childbirth injury model, including vaginal distension (VD) and pudendal nerve crush (PNC), may best represent the injuries seen clinically. The objective of this study was to investigate urethral function, anatomy, and neurotrophin expression after several simulated childbirth injuries. Groups of 140 rats underwent PNC, VD, PNC+VD, or neither (C). Four days after injury, all injury groups had significantly decreased leak-point pressure (LPP) compared with C rats. Ten days after injury, LPP in PNC and PNC+VD rats remained significantly lower than C rats. Three weeks after injury, LPP in all injury groups had recovered to C values. Histological evidence of injury was still evident in the external urethral sphincter (EUS) after VD and PNC+VD 10 days after injury. Three weeks after injury, the EUS of PNC+VD rats remained disrupted. One day after VD, brain-derived neurotrophic factor (BDNF) expression in the EUS was reduced, while neurotrophin-4 (NT-4) and nerve growth factor (NGF) expression was unchanged. BDNF, NT-4, and NGF expression was dramatically upregulated in the EUS after PNC. After PNC+VD, NGF expression was upregulated, and BDNF and NT-4 expression was upregulated somewhat but not to the same extent as after PNC. Ten days after injury, PNC+VD had the least number of normal nerve fascicles near the EUS, followed by PNC and VD. Twenty-one days after injury, all injury groups had fewer normal nerve fascicles, but without significant differences compared with C rats. PNC+VD therefore provides a more severe injury than PNC or VD alone.
The coronavirus disease 2019 (COVID-19) pandemic has had a global impact on all aspects of health care, including surgical procedures. For urologists, it has affected and will continue to influence how we approach the care of patients preoperatively, intraoperatively, and postoperatively. A risk-benefit assessment of each patient undergoing surgery should be performed during the COVID-19 pandemic based on the urgency of the surgery and the risk of viral illness and transmission. Patients with advanced age and comorbidities have a higher incidence of mortality. Routine preoperative testing and symptom screening is recommended to identify those with COVID-19. Adequate personal protective equipment (PPE) for the surgical team is essential to protect health care workers and ensure an adequate workforce. For COVID-19 positive or suspected patients, the use of N95 respirators is recommended if available. The anesthesia method chosen should attempt to minimize aerosolization of the virus. Negative pressure rooms are strongly preferred for intubation/extubation and other aerosolizing procedures for COVID-19 positive patients or when COVID status is unknown. Although transmission has not yet been shown during laparoscopic and robotic procedures, efforts should be made to minimize the risk of aerosolization. Ultra-low particulate air filters are recommended for use during minimally invasive procedures to decrease the risk of viral transmission. Thorough cleaning and sterilization should be performed postoperatively with adequate time allowed for the operating room air to be cycled after procedures. COVID-19 patients should be separated from noninfected patients at all levels of care, including recovery, to decrease the risk of infection. Future directions will be guided by outcomes and infection rates as social distancing guidelines are relaxed and more surgical procedures are reintroduced. Recommendations should be adapted to the local environment and will continue to evolve as more data become available, the shortage of testing and PPE is resolved, and a vaccine and therapeutics for COVID-19 are developed.
Aims
Stress Urinary Incontinence (SUI) affects women both acutely and chronically after vaginal delivery. Current SUI treatments assume the neuromuscular continence mechanism, comprised of the pudendal nerve (PN) and external urethral sphincter (EUS), is either intact or irreparable. This study investigated the ability of neurotrophin therapy to facilitate recovery of the neuromuscular continence mechanism.
Methods
Virgin, Sprague Dawley rats received simulated childbirth injury or sham injury and treatment with continuous infusion of brain derived neurotrophic factor (BDNF) or saline placebo to the site of PN injury. Continence was assessed by leak point pressure (LPP) and EUS electromyography (EMG) 14 and 21 days after injury. Structural recovery was assessed histologically. Molecular assessment of the muscular and neuroregenerative response was determined via measurement of EUS BDNF and PN βII-tubulin expression respectively, 4, 8, and 12 days after injury.
Results
Following injury, LPP was significantly reduced with saline compared to either BDNF treatment or sham injury. Similarly, compared to sham injury, resting EUS EMG amplitude and firing rate, as well as amplitude during LPP were significantly reduced with saline but not BDNF treatment. Histology confirmed improved EUS recovery with BDNF treatment. EUS BDNF and PN βII-tubulin expression demonstrated that BDNF treatment improved the neurogenerative response and may facilitate sphincteric recovery.
Conclusions
Continuous targeted neurotrophin therapy accelerates continence recovery after simulated childbirth injury likely through stimulating neuroregeneration and facilitating EUS recovery and re-innervation. Neurotrophins or other therapies targeting neuromuscular regeneration may be useful for treating SUI related to failure of the neuromuscular continence mechanism.
Purpose-Accuracy in the recording of external urethral sphincter (EUS) electromyography (EMG) is an important goal in the quantitative evaluation of urethral function. This study aim was to quantitatively compare electrode recordings taken during tonic activity and leak point pressure (LPP) testing.Methods-Several electrodes, including the surface electrode (SE), concentric electrode (CE), and wire electrode (WE), were placed on the EUS singly and simultaneously in six female SpragueDawley rats under urethane anesthesia. The bladder was filled via a retropubic catheter while LPP testing and EUS EMG recording were done. Quantitative baseline correction of the EUS EMG signal was performed to reduce baseline variation. Amplitude and frequency of one-second samples of the EUS EMG signal were measured before LPP (tonic activity) and during peak LPP activity.Results-The SE, CE, and WE signals demonstrated tonic activity before LPP and an increase in activity during LPP, suggesting that the electrodes accurately recorded EUS activity during tonic activity and during the bladder-to-EUS guarding reflex, regardless of the size or location of detection areas. SE recordings required significantly less baseline correction than both CE and WE recordings. The activity in CE-recorded EMG was significantly higher than that of the SE and WE both in single and simultaneous recordings.Conclusions-These electrodes may be suitable for testing EUS EMG activity. The SE signal had significantly less baseline variation and the CE detected local activity more sensitively than the other electrodes, which may provide insight into choosing an appropriate electrode for EUS EMG recording.
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