Lumbar spinal surgery may be associated with considerable pain in the early postoperative period. This often leads to a delay in patient mobilisation and a consequent increase in the risk of developing perioperative complications. Several studies have demonstrated the efficacy of intrathecal opioids for analgesia following spinal surgery.^1–3 Morphine has been the most widely studied opioid and although improved analgesia has been reported with its use the risk of serious side effects such as respiratory depression has resulted in patients having to be nursed postoperatively in a high dependency unit.² Intrathecal diamorphine has been widely used for analgesia following lower limb joint replacement where it is an effective analgesic agent with a good safety profile.^4–5 Its use for analgesia following lumbar spinal surgery has never been reported.

We present our experience of using intrathecal diamorphine for analgesia following lumbar spinal surgery. Data were collected on all patients undergoing surgery who received intrathecal diamorphine and stored on a database (Microsoft Access).

Results: 194 patients received intrathecal diamorphine following spinal surgery over a 30 month period. All patients underwent lower lumbosacral decompressive and/or fusion surgery. Mean dose of diamorphine administered was 1.6mg (range 1–4mg or 20–50mcg/kg). In all cases intrathecal diamorphine was administered by the anaesthetist once the patient was anaesthetised. Only 9% of patients had a pain score of 2 or greater within the first 24 hours (using a verbal rating scale 0–10). No patients required rescue analgesia with intravenous opiates. All patients except one were nursed on a regular orthopaedic ward. Side effects were rare. Respiratory depression occurred in one patient necessitating supplemental oxygen and monitoring in a high dependency unit for 12 hours. Hypotension was an infrequent finding (3.5%) but was most common upon return to the ward and in the following 24 hours. It was easily treated with the administration of intravenous fluids and vasopressors were never required. Sedation occurred in 4 of the patients whilst in the recovery ward but the incidence was nil once patients had been discharged to the orthopaedic ward. The most common complication recorded was pruritis, occurring in 9% of patients within the first 12 hours.

Conclusion: Intrathecal diamorphine is an effective and safe method of providing analgesia following lumbar spinal surgery. High Dependency nursing care is not required as the incidence of serious side effects is low.