外尿道括約肌肌電圖用於偵測脊髓損傷鼠的膀胱狀態

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，造成排尿功能低落，排尿不淨，增加尿路感染之風險。若長時間處在此病癥下，也容易造成腎臟及輸尿管水腫和腎功能病變，更甚者，導致慢性腎衰竭。 電刺激神經調控為一種新的治療方向，可取代受損神經來調控膀胱排尿功能，而偵測膀胱狀態進而在適當的時間點給電就顯得相當重要。目前臨床上是以尿道動力學檢查來偵測膀胱狀態，如體外超音波量測膀胱體積，或尿道插管量測膀胱內壓；但體外超音波無法對電刺激調控即時回饋，患者也無法長期尿道插管。本研究希望以外尿道括約肌肌電圖做為即時偵測膀胱狀態之依據，經過自製五級濾波放大器，由NI USB-6212資料擷取卡送入以LabVIEW撰寫的演算法，以移動視窗的方式處理，維持演算法適當的靈敏度並減少時間延遲，建立一套即時偵測膀胱狀態的系統，並以正常及脊髓損傷大白鼠進行實驗。 由ROC實驗結果統計，以外尿道括約肌肌電圖偵測膀胱狀態，與真實排尿狀態相比，在正常鼠方面精確度高達97%，而在脊髓損傷鼠方面則為90.3%，兩者皆相較於以膀胱內壓作為判斷依據來的高，由此證實了以外尿道括約肌肌電訊號取代膀胱內壓，作為膀胱狀態即時偵測的可行性，並可搭配資料擷取卡數位輸出功能，將偵測結果做為功能性電刺激器觸發給電依據，以期能對脊髓損傷病人的排尿功能改善做出貢獻。

Spinal cord injury is often accompanied with detrusor external urethral sphincter (EUS) dyssynergia, which may lead to low efficiency of micturition function and incomplete voiding, and increase the risk of urinary tract infection in the patients. Being under this symptom for a long period, a patient may also develop ureteral edema, renal damage, and even renal failure. Electrical neural moderation is one of the new treatment directions. It can provide the function that the damaged nerve originally does and improve the voiding efficiency. So it is critical to detect the status of bladder and give the muscle electrical stimulation at the right time. Nowadays clinical detection of the bladder status depends on urodynamic study, such as using external ultrasound to estimate the volume of the bladder, or placing a catheter through the urinary tract to measure the intravesical pressure. But external ultrasound can-not give the electrical neural moderation an immediate feedback; neither is it suitable for patients to catheterize for a long period. The objective of this study is to use EUS-electromyography (EMG) as detector of the bladder status. EMG signal is filtered and amplified by a 5-stage circuit, and processed by using a LabVIEW algorithm. A moving window method is used to decrease time delay and maintain moderated sensitivity of the algorithm, realizing a real-time detection of the bladder status. The algorithm is applied on normal rats and rats with spinal cord injury experimentally. From experimental result analyzed by ROC method, using EUS-EMG to detect the bladder status compared with real voiding status, the accuracies of voiding detection exhibit 97% in normal rats and 90.3% in those with spinal cord injury. The accuracies of both results are better than that from using intravesical pressures as detector. Those findings demonstrate the feasibility of this study. Signal output function of the DAQ card can be used to trigger functional electrical stimulation, which improves voiding function of patients with spinal cord injury.