Background: While most trials of thoracic paravertebral nerve blocks (TPVB) for breast surgery
show benefit, their effect on postoperative pain intensity, opioid consumption, and prevention
of chronic postsurgical pain varies substantially across studies. Variability may result from use of
different drugs and techniques.
Objectives: To examine the use of TPVB in breast surgery, and to determine which method(s)
provide optimal efficacy and safety.
Study Design: Mixed-Effects Meta-Analysis.
Methods: We conducted a systematic review of randomized trials comparing TPVB to no
intervention using random-effects models. To evaluate the contributions of various techniques,
clinical approaches were included as moderators in mixed-effects models.
Results: A total of 24 randomized controlled trials (RCTs) with 1,822 patients were included. Use
of TPVB decreased postoperative pain scores at rest and movement at the first 2, 24, 48, and 72
hours. TPVB modestly decreased intraoperative and postoperative opioid consumption, reduced
nausea and vomiting, and shortened hospitalization, but to a probably clinically irrelevant degree.
Blocks also appeared to reduce the incidence of chronic postsurgical pain at 6 months. Adding
fentanyl to the TPVB improved pain at rest (at 24, 48, and 72 hours) and movement (at 24 and 72
hours). Multilevel blocks provided better postoperative pain control, but only during movement (at
2, 48, and 72 hours). Fewer procedural complications (especially hypotension, epidural spread, and
Horner’s syndrome) occurred when anatomical landmarks were supplemented with ultrasound
guidance.
Limitations: The number of studies available was limited in the meta-analytic model of incidence
of chronic post-surgical pain.
Conclusion: TPVB reduces postoperative pain and opioid consumption, and has a limited
beneficial effect on the quality of recovery. From all the techniques that were evaluated, only
the addition of fentanyl, and performing multilevel blocks were associated with improved acute
analgesia. TPVB may reduce chronic postsurgical pain at 6 months.
Key words: Thoracic paravertebral block, breast surgery, anesthesia, acute pain, chronic pain,
nausea, vomiting, length of stay, techniques, variability, meta-regression, meta-analysis, moderators
Improving Analgesic Efficacy and Safety of
Thoracic Paravertebral Block for Breast Surgery:
A Mixed-Effects Meta-Analysis