Analgesic efficacy of pre‐operative stellate ganglion block on postoperative pain relief: a randomised controlled trial

Abstract

We undertook a randomised, double-blind, placebo-controlled study to compare the analgesic efficacy of pre-operative stellate ganglion block on postoperative pain relief after upper limb orthopaedic surgery. Patients were administered a 3-ml injection during ultrasound-guided stellate ganglion block; 15 patients received lidocaine 2% and 15 patients received 0.9% saline. Following the block, all patients received standardised general anaesthesia. Postoperative analgesia included regular intravenous diclofenac, paracetamol and patient-controlled analgesia with tramadol for 24 h. Patients were observed at 0, 2, 4, 6, 8, 12 and 24 h after surgery for tramadol consumption, cardiovascular variables and visual analogue scale pain scores at rest and on movement. The mean (SD) hourly tramadol consumption was significantly reduced in the lidocaine group compared with the saline group at 4 h (8.0 (10.1) mg vs 28.0 (12.6) mg, respectively; p = 0.001), 6 h (5.3 (10.8) mg vs 17.3 (12.7) mg, respectively; p = 0.013) and 8 h (5.3 (11.8) mg vs 21.3 (9.1) mg, respectively; p = 0.001). The cumulative 24-h tramadol consumption was 97.3 (16.6) mg in the lidocaine group and 150.6 (26.0) mg in the saline group (p = 0.001). There were significant differences in the pain visual analogue scale at rest at two time points; at 4 h the median (IQR [range]) visual analogue scale scores were 4 (4-6 [2-8]) in the lidocaine group and 5 (4-6 [2-7]) in the saline group (p = 0.03), and at 6 h visual analogue scale scores were 3 (3-4 [3-6]) and 4 (4-6 [2-7]), respectively (p = 0.04). Pain visual analogue scale on movement was lower in the lidocaine group at all time intervals compared with the saline group, but this did not reach statistical significance. The present study has demonstrated a postoperative tramadol-sparing and analgesic effect of pre-operative stellate ganglion block in patients undergoing upper limb orthopaedic surgery under general anaesthesia.

Invasive placebo revisited

“…report a small, well‐designed randomised trial investigating the efficacy of pre‐operative stellate ganglion block on pain relief after upper limb orthopaedic surgery. This study has several positive aspects, including the study rationale, originality (it is the first randomised controlled trial in this setting), the considerable precautions taken to maximise internal validity and minimise bias, the small dose of local anaesthetic utilised to elicit an effect, and the researchers' care in using ultrasound for needle placement . This study's design, on first reading, seems to have covered all the bases, including clear reporting of how the randomisation sequence was generated, allocation concealment, patient blinding and masking of the outcome assessor.…”

January 2015 Letter to the Editor-in-Chief

“…5 For example, preoperative blockage of the (sympathetic) stellate ganglion can reduce postoperative pain and the need for tramadol. 8 When compared to a nonpainful control condition, experimental acute pain increased HR and mean arterial BP (signs of stress-related sympathoexcitatory response) in young, healthy participants. 6 If acute pain can induce sympathoexcitatory response and if blockage of the sympathetic nervous system can reduce pain, then it may be reasonable to speculate that sympathoinhibitory response may reduce pain.…”

The case for invasive placebo – is the devil in the detail?

“…More importantly, there is even less evidence to support the concept that this interaction between nociceptive transmission and the autonomic nervous system works in a bidirectional fashion; that is, nociception stimulates the autonomic nervous system and also conversely the autonomic nervous system modulates nociceptive processing. In this regard, Kumar et al's work [1] is essential in exploring an area of pain and mechanistic nociceptive theory that is complex, incompletely defined and inadequately explored.…”

“…Various mechanisms make up this psychobiological phenomenon, and the different potential effects are dependent upon the disease context, the system and the therapeutic intervention being studied [10]. For the purposes of the study by Kumar et al [1], the effect being evaluated is that of placebo analgesia, the administration of a placebo that leads to pain relief and/or reduced analgesic use. Much of the research exploring the placebo effect has been conducted in the field of pain and analgesia.…”

“…In this issue of Anaesthesia we publish a paper by Kumar et al evaluating the effect of pre-operative stellate ganglion block on postoperative tramadol consumption following surgery to fixate upper limb fracture [1]. This research study was prompted by the 2011 case series from McDonnell et al that showed a marked benefit of stellate ganglion block performed for similar indications with respect to postoperative pain scores and analgesic requirements [2].…”