Effects of Intraoperative Magnesium Sulfate on Perioperative Pain Relief After Spine Surgery
Status:
Completed
Trial end date:
2020-05-05
Target enrollment:
Participant gender:
Summary
The treatment of postoperative pain is increasingly based on a multimodal approach and
although opioids remain the drug of choice, they are often used in combination with other
analgesics (paracetamol, cyclooxygenase inhibitors or non-steroidal anti-inflammatory drugs)
and co-analgesic agents (clonidine and anti- NMDA such as ketamine or MgSO4). The rationale
for combined analgesia is to achieve additive or synergistic analgesic properties while
decreasing the incidence of side effects by reducing the dose of each agent. Nociceptive
stimuli are known to activate the release of the excitatory amino acid glutamate in the
dorsal horn of the spinal cord. The resultant activation of NMDA receptors causes calcium
entry into the cell and triggers central sensitisation. This mechanism is involved in the
perception of pain and mainly accounts for its persistence during the postoperative period.
Although magnesium is not a primary analgesic in itself, it enhances the analgesic actions of
more established analgesics as an adjuvant agent. Magnesium produces a voltage-dependent
block of NMDA receptors and has been reported to have analgesic properties that might be
related to this inhibiting property. Magnesium sulfate has been reported to be effective in
perioperative pain treatment and in blunting somatic, autonomic and endocrine reflexes
provoked by noxious stimuli.
When magnesium was used intraoperatively, many researchers reported that it reduced the
requirement for anesthetics and/or muscle relaxants.
Intraoperative use of magnesium sulfate can also be associated with decreased incidences of
nausea and vomiting after surgery, which could have been due to the lower consumption of
anesthetics (i.e. volatile agents), rather than any antiemetic effect of magnesium sulfate.
In addition, perioperative i.v. administration of magnesium sulfate has another advantageous
effect, as it decreases the incidence of shivering by up to 70-90%. Previous studies
investigating the analgesic efficacy of MgSO4 in general, gynaecological, ophthalmic and
orthopaedic surgery have shown conflicting results, while reports regarding spine surgery are
extremely limited.
Our study was designed to investigate the effects of MgSO4 on perioperative pain relief and
postoperative quality of recovery after lumbar laminectomy surgery.