Epidural analgesia for pain relief following hip or knee replacement

 

Abstract

Background

Hip and knee replacement are common operative procedures to improve mobility and quality of life. Adequate pain relief is essential in the postoperative period to enable ambulation and initiation of physiotherapy. Lumbar epidural analgesia is a common modality for pain relief following these procedures. As the use of epidural analgesia may delay the initiation of anticoagulant thromboprophylaxis due to the potential risk of epidural hematoma, a synthesis of the evidence is necessary to determine whether or not alternative analgesic modalities are worse, equivalent, or better than epidural analgesia.

Objectives

Is lumbar epidural analgesia more efficacious than systemic analgesia or long-acting spinal analgesia for postoperative pain relief in patients after elective hip or knee replacement?

Search methods

MEDLINE, EMBASE, CINAHL, LILACS, and the CENTRAL were searched from their inception to June 2001.

Selection criteria

A study was included if it was a randomized or pseudo randomized controlled clinical trial (RCT) of patients undergoing hip or knee replacement, in which postoperative lumbar epidural analgesia was compared to other methods for pain relief. Study selection was performed unblinded in duplicate.

Data collection and analysis

Data were collected unblinded in duplicate. Information on patients, methods, interventions, outcomes (pain relief, postoperative function, length of stay) and adverse events were recorded. Methodological quality was assessed using a validated 5-point scale. Meta-analysis was conducted when sufficient data existed from two or more studies. Heterogeneity testing was performed using the Breslow-Day method. The fixed-effect model was used unless heterogeneity was present, in which case, a random-effects model was used. Continuous data were summarized as weighted mean differences (WMD) or standardized mean differences (SMD) with 95% confidence intervals (CI). Dichotomous data were summarized as odds ratios (OR) and numbers-needed-to-treat-to-benefit (NNT) or numbers-needed-to-treat-to-harm (NNH) with their respective 95% CI.

Main results

In the first four to six hours after surgery, patients receiving epidural analgesia had less pain at rest, based on visual analog scores (VAS), than patients receiving systemic analgesia (SMD -0.77; 95% CI -1.24 to -0.31). This effect was not statistically significant by 18 to 24 hours (SMD -0.29; 95% CI -0.73 to 0.16). These observations were based only on studies evaluating populations consisting of total knee replacements alone or mixed populations of total hip or total knee replacements. For pain relief with movement after surgery, patients receiving epidural analgesia reported lower pain scores than patients receiving systemic analgesia in all four studies examining these outcomes. The choice of epidural agents may also influence the extent to which epidural analgesia differs from systemic analgesia. The differences between epidural analgesia and systemic analgesia in the frequency of nausea and vomiting (OR 0.95; 95% CI 0.60 to 1.49) or depression of breathing (OR 1.07; 95% CI 0.45 to 2.54) were not statistically significant. Sedation occurred less frequently with epidural analgesia (OR 0.30; 95% CI 0.09 to 0.97) with a number-needed-to-harm of 7.7 (95% CI 3.5 to 42.0) patients for the systemic analgesia group. Retention of urine (OR 3.50, 95% CI 1.63 to 7.51; NNH 4.5, 95% CI 2.3 to 12.2), itching (OR 4.74, 95% CI 1.76 to 12.78; NNH 6.8, 95% CI 4.4 to 15.8), and low blood pressure (OR 2.78, 95% CI 1.15 to 6.72; NNH 6.7, 95% CI 3.5 to 103) were more frequent with epidural analgesia compared to systemic analgesia. There were insufficient numbers to draw conclusions on the effect of epidural analgesia on serious postoperative complications, functional outcomes, or length of hospital stay.

Authors' conclusions

Epidural analgesia may be useful for postoperative pain relief following major lower limb joint replacements. However, the benefits may be limited to the early (four to six hours) postoperative period. An epidural infusion of local anaesthetic or local anaesthetic-narcotic mixture may be better than epidural narcotic alone. The magnitude of pain relief must be weighed against the frequency of adverse events. The current evidence is insufficient to draw conclusions on the frequency of rare complications from epidural analgesia, postoperative morbidity or mortality, functional outcomes, or length of hospital stay.

 

Plain language summary

Epidural analgesia (a form of pain control) for the pain relief following hip and knee replacement

Epidural analgesia may give good pain relief after hip or knee replacement surgery, but this benefit must be weighed against the possibility of adverse effects and complications. Hip and knee replacements are common operations to improve mobility and quality of life. After surgery, good pain relief is essential to enable patients to start walking again. Epidurals (pain medicine injected into the spinal canal) are commonly used. However, this pain relief method may delay the start of blood thinners, which prevent life-threatening blood clot formation (thrombosis) in veins, because there is also a risk of bleeding at the epidural injection site if blood thinners are used at the same time. This review found that an epidural comprising local anaesthetic with or without a strong opioid might give better pain relief than an epidural with only strong opioids; the benefit may be felt only in the first four to six hours after surgery. Aside from pain relief, there was insufficient information to draw conclusions on other benefits or harms arising from epidural analgesia.

 

摘要

背景

使用硬膜外止痛(Epidural analgesia)緩解髖關節或膝關節置換術之術後疼痛

髖關節和膝關節置換術在改善病人活動力和生活品質，是常見的手術程序。提供充足術後止痛對術後的步行和開始物理治療是特別重要的。腰椎硬膜外止痛是一種常見緩解以上治療程序止痛的方式。不過，尚無完整評論證明硬膜外止痛與其他術後止痛方式比較其有效性。因使用硬膜外止痛之注射藥物會延遲啟動抗凝劑的血栓預防機制，可能會產生硬膜外血腫的潛在風險，因此決定是否選擇其它止痛方式會比硬脊瞙外止痛方式會更糟、相當或更好的證據是必要的。

目標

我們的目的是要回答這個問題：“在隨意的髖關節或膝關節置換術後之術後疼痛治療，腰椎硬膜外止痛是否比全身性止痛或長期可活動性脊髓止痛術更有效？”

搜尋策略

我們搜尋了MEDLINE，CINAHL，LILACS，和the Cochrane Controlled Trials Register 從開始至2001年6月。評論文章和被囊括的研究中的參考清單，也被額外的引用。

選擇標準

我們收納了隨機或偽隨機對照臨床試驗，只要是接受髖關節或膝關節置換術的病人，術後接受腰椎硬膜外止痛，即被列為和其他減輕疼痛方法的比較對象。研究選擇是在沒有任何隱瞞下重複執行。

資料收集與分析

在沒有任何隱瞞下重複執行數據收集。病人相關的信息，處理的方法，治療和結果(緩解疼痛，術後功能，滯留醫院時間)和不良影響皆被一一的記錄下來。使用方法學量化的5點尺規評分表進行質量分析。當存在兩個或兩個以上的研究且足夠的數據時，將進行綜合分析(Metaanalysis)。異質性測試將使用BreslowDay method呈現。除非有異質性出現，才會使用固定效應模式(fixed effects model)，否則，一般情況下皆使用隨機效應模式(random effects model)。連續數據被概括為：加權平均差異(weighted mean differences ；WMD)或標準化的平均差異(standardized mean differences ；SMD)，以95 ％的信賴區間(CI)來呈現。二分數據被計算為勝算比(OR)和多少需要到治療(NNT)或多少需要到傷害(NNH)且具95 ％ CI。連續數據採用MetaView program圖表呈現。

主要結論

在手術後頭4至6小時，在休息狀態時，使用視覺模擬分數(VAS)評估病人，接受硬膜外止痛方式比接受全身性止痛之病人感覺比較不痛(標準化的平均差異−0.77 ; 95 ％ CI 為−1.24到−0.31)。這樣的止痛作用在術後18至24小時已無統計意義(標準化的平均差異−0.29 ; 95 ％ CI為−0.73到 0.16)。這些觀察意見僅根據研究全膝關節置換或合併人工全髖關節置換或人工全膝關節置換所得之結果。所有4個研究的成果發現，對術後活動時疼痛減輕的情形，接受硬膜外止痛的病人比接受全身止痛的病人，有較低的疼痛分數。硬膜外致效劑的選擇可能對硬膜外止痛有不同程度的影響，此與全身止痛有所不同。硬膜外止痛和全身止痛的之間在噁心和嘔吐的頻率的差異，(OR 0.95 ; 95％ CI為0.60至1.49)，呼吸抑制方面((OR 1.07 ; 95％ CI 為0.45至2.54)，但是沒有統計意義。鎮靜作用方面，硬膜外止痛發生的頻率較低，(OR 0.30; 95％ CI為0.09 至0.97)，與全身止痛相比，NNH為7.7 (95％ CI為3.5 至42.0);尿液滯留方面(OR3.50; 95％ CI為1.63 至7.51)，NNH為4.5(95％ CI為2.3 至12.2);搔癢(OR 4.74; 95％ CI為1.76 至12.78)，NNH為6.8(95％ CI為4.4 至15.8);和低血壓(OR 2.78; 95％ CI為1.15 至6.72)，NNH為6.7(95％ CI 為3.5 至103);與全身止痛相比硬膜外止痛發生的頻率更頻繁。沒有足夠的病人數來做硬脊膜外止痛對嚴重的手術併發症，功能性的成果或住院時間的影響。

作者結論

硬膜外止痛對主要下肢關節置換的術後疼痛緩解可能是有用效的。不過，好處可能只限於術後早期(4至6個小時)。硬膜外注射局部麻醉劑或局部麻醉劑麻醉合劑可能優於硬膜外單獨的麻醉劑使用。疼痛緩解的重要性也必須權衡製劑造成不良影響的頻率。硬膜外止痛造成術後併發症或死亡，功能性的成果的影響，或住院時間的長短，目前的證據尚不足以做出任何的結論。

翻譯人

本摘要由三軍總醫院謝凱芝翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

硬膜外止痛可提供髖關節或膝關節置換手術後良好的疼痛緩解，但此益處必須多方面權衡所使用的製劑對髖關節或膝關節置換手術後活動和生活品質改善時，也可能發生的不利影響和併發症。手術後，良好的疼痛緩解是讓病人重新開始步行不可少的因素。硬膜外止痛(止痛藥注射到椎管)是普遍使用的方法。不過，這減輕疼痛的方法可能會延誤血液稀釋劑開始作用，雖然它可以防止威脅生命的靜脈血栓的形成，但它也可能造成硬膜外注射部位也有出血的風險。本篇發現，在手術後4 – 6小時，硬膜外注射局部麻醉，不論有無合併鴉片類藥物與否，都比硬膜外單獨使用鴉片類藥物有較好的止痛效果。除了止痛效果，硬膜外止痛所引其他方面的利益或損害尚無足夠的資料得出結論。