會陰神經電刺激對於脊髓外傷大白鼠排尿功能之影響

Abstract

脊髓損傷病人常會伴隨著膀胱與外尿道括約肌共濟失調之現象，而造成排尿功能低落，排尿不淨，增加尿路感染知風險。若長時間處在此病徵下，也容易造成腎臟及輸尿管水腫和腎功能病變，更甚者，導致慢型腎衰竭。 電刺激療法為最新的治療方向，可取代損傷神經來調控膀胱排尿功能，適用於治療神經性膀胱。利用小型開口式環狀電極置入脊髓損傷大白鼠之會陰神經部位。以低電流(約0.03 mA)刺激其單側感覺分支(n=4)，可有效增加大白鼠之排尿效率(約10%增加至30%)，施以高電流(0.2mA)則可抑制大白鼠膀胱收縮。此外，於雙側運動分支施行高頻阻斷，以電流(n=4,10k~20kHz)會導致外尿道括約肌放鬆。而在停止施予高頻阻斷技術後，其膀胱內壓可復原至高頻阻斷前之狀態，可見高頻阻斷電流對於神經並無明顯急性傷害。整合型電刺激模式(n=4)於單側會陰神經可提升排尿效率30~40%，單側運動分支高頻阻斷對於排尿效率提升仍然有限。 此實驗目前已證實，結合功能性電刺激及高頻阻斷技術可調控脊髓損傷大白鼠的排尿功能。預期未來可進一步藉由排空週期內會陰神經活動之相關研究，以電刺激模擬其正常排尿反射模式，進而更有效提升膀胱排尿功能。

Spinal cord injured (SCI) patients often accompanied detrusor-EUS dyssynergia (DSD) who have low efficiency of micturition function and incomplete voiding, and increase the risk of urinary tract infection. Long-term period under this situation will cause ureteral edema, renal damage, and even renal failure. Functional electrical stimulation is a new treatment direction for replacement of the permanent nerve damage to improve the voiding function in neurogenic bladder. In our study, micro-side opened cuff electrode was placed on the pudendal nerve in SCI rats. Low amplitude (~0.03mA) of low frequency stimulation (LFS) delivered on the unilateral sensory branch of the pudendal nerve significantly increased the voiding efficiency from 10% to 30% in SCI animals. However, high amplitude current (~0.2mA) inhibited the bladder emptying. On the other hand, high frequency blocking (HFB, 10 kHz or 20 kHz) applied on the bilateral motor branches of the pudendal nerve relaxed the EUS. After applying HFB on the motor branch, the cystometrogram (CMG) would recover back to control CMG pattern. Therefore, the HFB current did not likely cause dramatic neural damage. The simultaneous applications of LFS and HFB on the unilateral pudendal nerve also dramatically increased the voiding efficiency up to 30~40%. However, the unilateral motor branch with applying HFB was likely ineffective to inprove bladder emptying. In this study, the LFS combined with the HFB technique was successful to modulate the bladder voiding function in SCI rats. In the future, we should further to investigate the pudendal nerve activity during voiding cycle to establish a mimic model of voiding pattern, and the results integrating our current results would produce a more efficient voiding.