脊髓電刺激器與疼痛評估方法之研究

Studies of Spinal Cord Stimulator for Pain Relief

莊炯承(Chiung-Cheng Chuang)

指導教授 ： 鍾文耀

中原大學/工學院/電子工程研究所/博士(2007年)

https://doi.org/10.6840/cycu200700072

摘要

摘 要
慢性頑固性疼痛是醫學界的一大痼疾，一般常規性的治療方法均不易有效控制。然而，脊髓神經刺激療法對適當篩選過後的此類病患卻有顯著療效，所以此技術勢將成為慢性頑固性疼痛未來治療的趨勢。
脊髓神經刺激療法始於1967年，初期由於尚未充分建立適應症以及適當的患者篩選機制，治療效果往往不如預期。直到近幾年以來，經過微刺激器與植入技術不斷的發展與改進以及適應症的陸陸續續建立，更重要的是利用正式植入前的臨時性刺激試驗，進行適當的病患評估與篩選，使此療法的止痛效果大為提升，進而使國際上再度興起以脊髓電刺激器治療慢性頑固性疼痛。
本研究針對脊髓刺激療法研發一套疼痛評估輔助系統，藉以加強此療法在初期試驗與正式植入後止痛療效的評估。整體實驗內容包含兩大部分：首先，建立以心率/血壓變異度分析為核心技術的疼痛評估系統，然後再利用此系統先在實驗室觀察並分析各種實驗條件下，經壓痛計給予疼痛刺激後的心率/血壓變異度變化，進而找出疼痛與各種分析參數或實驗條件之間的關係。其次，以臨床試驗來分析慢性疼痛病患在物理治療前後，其疼痛緩解程度與心率變異度參數之間的關連性，同時驗證以心率變異度作為疼痛指標的可行性。實驗結果發現，疼痛刺激與疼痛緩解均對生理訊號的變異產生若干影響，並且明顯反應在相關的時頻域參數上。
除了疼痛評估之外，本研究還開發出一新型的植入式脊髓神經電刺激器，將傳統以微處理機為核心之系統架構，改採以脈衝寬度調變技術來調控輸出電流源之刺激參數，如此一來，不但可簡化系統架構並縮小電路晶片面積，同時還可降低功率耗損與製作成本，甚至對脊髓刺激療法的推廣亦有相當的助益。
綜合以上所述，本研究不僅改善了脊髓神經刺激器的核心電路架構，而且亦提供了一個以生理訊號做為疼痛評估與監測的簡單且可行的方法，這一些成果將可提供未來進一步研究對抗頑固性疼痛之基礎。

關鍵字

心率變異度、血壓變異度 ； 疼痛 ； 脊髓神經刺激器 ； 脊髓神經刺激

並列摘要

Abstract
Intractable chronic pain is the most troublesome medical science disease and is difficult to effectively control through regular therapies. Spinal cord stimulation is directed against chronic trunk or limb pain and is very effectual for properly screened patients suffering from intractable chronic pain. In America and Europe, spinal cord stimulation technology is extensively applied to control chronic pain caused from various etiologies and is becoming the future trend for intractable chronic pain treatment.
Spinal Cord Stimulation originated in 1967. Deficient spinal cord stimulation indications and patient screening mechanisms frustrated initial healing results. Until recent microstimulator and implantation expansion and improvement, spinal cord stimulation indications were established one at a time. Proper patient assessment and screening is vital by inserting a lead before implanting Spinal Cord Stimulation system. Analgesic effect of this treatment therefore can be improved substantially, using spinal cord stimulation to treat intractable chronic pain.
A pain assessment system is first developed in this study to enhance analgesic effect measurement of spinal cord stimulation in the two periods, trial screening and implantation. The experiment includes two stages, first, establishing a pain assessment system based on heart rate variability (HRV) analysis as the core technology. The assessment system observes and analyzes heart rate variances stimulated by the algometer under various experimental conditions to find out the relationship between pain and various analytical parameters or experimental conditions. Second, the relationship between the degree of pain relief and change of heart rate variability by means of clinical test on chronic pain patients before and after physical treatment is analyzed to verify the feasibility of using HRV parameters as a pain index.
Results show that both pain stimuli and pain relief influence biosignal variance and significantly affect related time and frequency parameters. Furthermore, HRV parameters could usefully evaluate treatment program effectiveness and monitor pain variation. They might also help obtain optimum parameters to meet individual needs in spinal cord stimulation applications.
A novel implantable spinal cord stimulator is also explored to control output current source stimulation parameters, easily expanding its parameter range to suit more patients. Parameter programming is designed with a pulse width modulation technique, differing from the traditional microstimulator framework. Parameter programming simplifies system architecture and shrinks chip size, reducing power consumption and costs. Results reveal that stimulation waveform could contain biphasic pulses and conform to health care market main SCS product specifications.
This research achievement can provide, not only a pain assessment method, but also promote widespread spinal cord stimulation. It might help fight off aggressive intractable chronic pain.

並列關鍵字

Spinal Cord Stimulation ； Pain ； Heart Rate Variability ； Spinal Cord Stimulator ； Blood Pressure Variability

參考文獻

[1] Melzack R., Wall PD., “Pain mechanism: a new theory,” Science, vol. 150, pp. 971-978, 1965.

[2] Burchiel KJ, Anderson VC, Brown FD, et al., “Prospective, multicenter study of spinal cord stimulation for relief of chronic back and extremity pain”, Spine, vol. 21, pp. 2786-2794, 1996.

[3] Phillips DM., JCAHO, “Pain management standards are unveiled,” JAMA, vol. 284, pp. 726-733, 2000.

[5] Patrick L, D’Eon J. “Social support and functional status in chronic pain patients,” Canadian Journal of Rehabilitation, vol. 9, pp. 195-201, 1996.

[7] Akselrod S., Gordon D., Ubel FA., Shannonet DC., Barger AC., Cohen RJ., “Power spectrum analysis of heart rate fluctuation: A quantitative probe of beat-to-beat cardiovascular control,” Science, vol. 213(10), pp. 220-223, 1981.