Clinical Evaluation of Analgesic Efficacy of Intrathecal Morphine in Thoracic Surgery

BACKGROUND: In thoracic surgery, pain intensity resulting from nociceptive stimulation due to skin incision, muscle trauma, rib retraction, and pleural dissection contributes to central sensitization and the development of severe postoperative pain, particularly in the early postoperative period. Intrathecal administration of morphine represents an alternative opioid-sparing component of multimodal acute pain management.

AIM: The work aimed to clinically evaluate the analgesic efficacy of intrathecal morphine in patients undergoing thoracic surgery.

METHODS: The study included 255 patients who underwent thoracoscopic lobectomy. Patients were allocated into three groups: group 1 (n = 85) received intrathecal morphine; group 2 (n = 85) received systemic opioid analgesics; and group 3 (n = 85) received intercostal nerve blockade with ropivacaine. Pain intensity was assessed 2 and 24 hours postoperatively, along with the need for rescue analgesia (trimeperidine or tramadol) and the incidence of postoperative nausea and vomiting, pruritus, urinary retention requiring bladder catheterization, and delayed respiratory depression.

RESULTS: Two hours after surgery, pain intensity was lowest in the intercostal nerve block group (4 [3–4] cm on the visual analog scale [VAS]) and slightly higher in the intrathecal morphine group (4 [4–5] cm on the VAS). Both groups demonstrated a significantly greater analgesic effect compared with the systemic opioid analgesia group (6 [5–6] cm on the VAS; p < 0.001). At 24 hours postoperatively, pain intensity in group 1 decreased to 3 [2–3] cm on the VAS, whereas in group 2 it increased to 6 [5–6] cm, comparable with group 3 (6 [5–6] cm; p < 0.001). Trimeperidine consumption was significantly lower in group 1 (p < 0.001). The frequency of tramadol administration was also reduced (p < 0.001). The highest incidence of postoperative nausea and vomiting was observed in group 2 (p < 0.001). The incidence of pruritus and urinary retention did not differ significantly among groups. No cases of delayed respiratory depression were reported.

CONCLUSION: Intrathecal administration of morphine significantly reduced pain intensity, decreased the need for opioid analgesics, and was associated with a low incidence of pruritus within the first 24 hours after surgery. The incidence of postoperative nausea and vomiting was lower compared with both systemic opioid analgesia and intercostal nerve block. The need for urinary catheterization did not differ among groups. No delayed respiratory depression was observed.