Paravertebral block versus thoracic epidural for patients undergoing thoracotomy

Review question

We reviewed the evidence about the effect of paravertebral block and thoracic epidural for patients undergoing thoracotomy. We found 14 studies.

Background

Operations on structures in the chest (usually the lungs) involve cutting between the ribs (thoracotomy) resulting in severe pain. Poor pain relief post-surgery can slow down recovery and increase risks of developing complications. Effective management of acute pain following thoracotomy may prevent these complications and reduce the likelihood of developing long-term pain. We wanted to discover whether blocking the nerves as they emerge from the spinal column (paravertebral block, (PVB)) was better or worse than using central neuraxial nerve block (thoracic epidural block, (TEB)).

This evidence is current to 16th October 2013. We reran the search on 31st January 2015. We found one additional study which is awaiting classification and which we will include when we update the review.

Study characteristics

We found 14 studies involving 698 participants. Whilst all 14 studies compared broadly the analgesic efficacy of PVB and TEB in participants undergoing open thoracotomy, there were significant differences in the timing, method of insertion and medications used in PVB and TEB. This makes direct comparison difficult. Patient follow-up was limited to the immediate post-surgery period (up to five days post-surgery) with only two studies reporting long-term outcomes such as chronic pain. There are two studies awaiting classification.

Key results

We found no difference between PVB and TEB in terms of death at 30 days and major complications. PVB appeared to be as effective as TEB in pain control post-surgery. TEB was associated with minor complications such as low blood pressure, nausea and vomiting, itching and urinary retention when compared to PVB. We did not find any difference in length of hospital stay between PVB and TEB. There was insufficient information to assess chronic pain and health costs.

Quality of evidence

We found low-quality evidence for death at 30 days, with limited information provided by only two studies reporting this outcome. We only found low to very low-quality evidence for major complications due to lack of information, with only one study reporting these outcomes. We found moderate-quality evidence for acute pain control in the immediate postoperative period. We found moderate-quality evidence for minor complications.

Authors' conclusions: 

Paravertebral blockade reduced the risks of developing minor complications compared to thoracic epidural blockade. Paravertebral blockade was as effective as thoracic epidural blockade in controlling acute pain. There was a lack of evidence in other outcomes. There was no difference in 30-day mortality, major complications, or length of hospital stay. There was insufficient data on chronic pain and costs. Results from this review should be interpreted with caution due to the heterogeneity of the included studies and the lack of reliable evidence. Future studies in this area need well-conducted, adequately-powered RCTs that focus not only on acute pain but also on major complications, chronic pain, length of stay and costs.

Read the full abstract...
Background: 

Operations on structures in the chest (usually the lungs) involve cutting between the ribs (thoracotomy). Severe post-thoracotomy pain can result from pleural (lung lining) and muscular damage, costovertebral joint (ribcage) disruption and intercostal nerve (nerves that run along the ribs) damage during surgery. Poor pain relief after surgery can impede recovery and increase the risks of developing complications such as lung collapse, chest infections and blood clots due to ineffective breathing and clearing of secretions. Effective management of acute pain following thoracotomy may prevent these complications and reduce the likelihood of developing chronic pain. A multi-modal approach to analgesia is widely employed by thoracic anaesthetists using a combination of regional anaesthetic blockade and systemic analgesia, with both non-opioid and opioid medications and local anaesthesia blockade.

There is some evidence that blocking the nerves as they emerge from the spinal column (paravertebral block, PVB) may be associated with a lower risk of major complications in thoracic surgery but the majority of thoracic anaesthetists still prefer to use a thoracic epidural blockade (TEB) as analgesia for their patients undergoing thoracotomy. In order to bring about a change in practice, anaesthetists need a review that evaluates the risk of all major complications associated with thoracic epidural and paravertebral block in thoracotomy.

Objectives: 

To compare the two regional techniques of TEB and PVB in adults undergoing elective thoracotomy with respect to:

1. analgesic efficacy;
2. the incidence of major complications (including mortality);
3. the incidence of minor complications;
4. length of hospital stay;
5. cost effectiveness.

Search strategy: 

We searched for studies in the Cochrane Central Register of Controlled Trials (CENTRAL 2013, Issue 9); MEDLINE via Ovid (1966 to 16 October 2013); EMBASE via Ovid (1980 to 16 October 2013); CINAHL via EBSCO host (1982 to 16 October 2013); and reference lists of retrieved studies. We handsearched the Journal of Cardiothoracic Surgery and Journal of Cardiothoracic and Vascular Anesthesia (16 October 2013). We reran the search on 31st January 2015. We found one additional study which is awaiting classification and will be addressed when we update the review.

Selection criteria: 

We included all randomized controlled trials (RCTs) comparing PVB with TEB in thoracotomy, including upper gastrointestinal surgery.

Data collection and analysis: 

We used standard methodological procedures expected by Cochrane. Two review authors (JY and SG) independently assessed the studies for inclusion and then extracted data as eligible for inclusion in qualitative and quantitative synthesis (meta-analysis).

Main results: 

We included 14 studies with a total of 698 participants undergoing thoracotomy. There are two studies awaiting classification. The studies demonstrated high heterogeneity in insertion and use of both regional techniques, reflecting real-world differences in the anaesthesia techniques. Overall, the included studies have a moderate to high potential for bias, lacking details of randomization, group allocation concealment or arrangements to blind participants or outcome assessors. There was low to very low-quality evidence that showed no significant difference in 30-day mortality (2 studies, 125 participants. risk ratio (RR) 1.28, 95% confidence interval (CI) 0.39 to 4.23, P value = 0.68) and major complications (cardiovascular: 2 studies, 114 participants. Hypotension RR 0.30, 95% CI 0.01 to 6.62, P value = 0.45; arrhythmias RR 0.36, 95% CI 0.04 to 3.29, P value = 0.36, myocardial infarction RR 3.19, 95% CI 0.13, 76.42, P value = 0.47); respiratory: 5 studies, 280 participants. RR 0.62, 95% CI 0.26 to 1.52, P value = 0.30). There was moderate-quality evidence that showed comparable analgesic efficacy across all time points both at rest and after coughing or physiotherapy (14 studies, 698 participants). There was moderate-quality evidence that showed PVB had a better minor complication profile than TEB including hypotension (8 studies, 445 participants. RR 0.16, 95% CI 0.07 to 0.38, P value < 0.0001), nausea and vomiting (6 studies, 345 participants. RR 0.48, 95% CI 0.30 to 0.75, P value = 0.001), pruritis (5 studies, 249 participants. RR 0.29, 95% CI 0.14 to 0.59, P value = 0.0005) and urinary retention (5 studies, 258 participants. RR 0.22, 95% CI 0.11 to 0.46, P value < 0.0001). There was insufficient data in chronic pain (six or 12 months). There was no difference found in and length of hospital stay (3 studies, 124 participants). We found no studies that reported costs.

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