[Postoperative pain control with intrathecal morphine in patients undergoing vertebral fusion with instrumentation]

Proper postoperative pain management in patients undergoing vertebral arthrodesis with instrumentation is essential to reduce postoperative morbidity and mortality. Intrathecal morphine may provide effective analgesia minimizing the dose required and adverse side effects. The objective of this study is to assess the efficacy of intrathecal morphine to control postoperative pain in patients undergoing vertebral arthrodesis with instrumentation.

A prospective randomized trial was conducted; it included 46 patients who underwent vertebral fusion with instrumentation. Patients were randomly divided into two groups: one of them received a 0.003 mg/kg dose of intrathecal morphine before closing the surgical wound. The following parameters were recorded during the postoperative period: respiratory rate, PCO₂, PO₂, need for adjuvant anesthesia and subjective pain assessment with the visual analog scale (VAS), at 6, 24 and 48 hours after the surgery. The results were analyzed with non-parametric tests.

Patients who received intrathecal morphine had a statistically significant decrease in postoperative pain within 48 hours after the surgery, with a mean VAS score close to 3. In 24.1 percent of patients had complications associated with the use of morphine chloride, such as nausea and vomiting, without any statistically significant differences compared with the control group.

Intrathecal morphine is a safe and effective treatment option to control early postoperative pain in patients undergoing vertebral fusion with instrumentation. This leads to a more convenient and quick recovery.