Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Urology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, PR China.
Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.
Exp Neurol. 2021 Jun;340:113658. doi: 10.1016/j.expneurol.2021.113658. Epub 2021 Feb 24.
Neurogenic bladder management after spinal cord injury (SCI) is very challenging. Daily urethral catheterization is most commonly used to empty the bladder, which causes frequent infections of the lower urinary tract. This study reports a novel idea to restore both continence and micturition after SCI by an implantable pudendal nerve stimulator (PNS). The PNS was surgically implanted in four cats with complete SCI at T9-T10 spinal level and tested weekly for 13-14 weeks under awake conditions. These chronic SCI cats consistently exhibited large residual bladder volumes (average 40-50 ml) due to their inability to void efficiently, while urine leakage also occurred frequently. The PNS which consisted of stimulating the pudendal nerve at 20-30 Hz to trigger a spinal reflex bladder contraction and at the same time blocking the pudendal nerves bilaterally with 10 kHz stimulation to relax the external urethral sphincter and reduce the urethral outlet resistance successfully induced highly efficient (average 80-100%), low pressure (<50 cmHO) voiding. The PNS at 5 Hz also promoted urine storage by inhibiting reflex bladder activity and increasing bladder capacity. At the end of 14-week chronic testing, low pressure efficient voiding induced by PNS was further confirmed under anesthesia by directly measuring voiding pressure using a bladder catheter inserted through the bladder dome. This study demonstrated the efficacy and safety of the PNS in awake chronic SCI cats, suggesting that a novel neuroprosthesis can be developed for humans to restore bladder function after SCI by stimulating and/or blocking the pudendal nerves.
脊髓损伤(SCI)后的神经源性膀胱管理极具挑战性。最常使用每日尿道导管排空膀胱,这会导致下尿路频繁感染。本研究报告了一种通过植入阴部神经刺激器(PNS)恢复 SCI 后控尿和排尿的新方法。将 PNS 植入四只 T9-T10 脊髓水平完全 SCI 的猫中,并在清醒状态下每周测试 13-14 周。由于这些慢性 SCI 猫无法有效地排空尿液,因此其膀胱残留容量始终很大(平均 40-50ml),同时也经常发生尿失禁。PNS 通过以 20-30Hz 刺激阴部神经以引发脊髓反射性膀胱收缩,同时以 10kHz 刺激双侧阴部神经以放松尿道外括约肌并降低尿道出口阻力,成功地诱导了高效(平均 80-100%)、低压(<50cmHO)排尿。PNS 以 5Hz 刺激还通过抑制反射性膀胱活动和增加膀胱容量来促进尿液储存。在 14 周慢性测试结束时,通过直接测量通过插入膀胱穹窿的膀胱导管测量的排尿压力,在麻醉下进一步证实了 PNS 诱导的低压高效排尿。本研究证明了 PNS 在清醒慢性 SCI 猫中的有效性和安全性,表明可以开发新型神经假体通过刺激和/或阻断阴部神经来恢复 SCI 后的膀胱功能。