Effects of ultrasound-guided mid-point transverse process to pleura block on acute pain intensity and chronic pain incidence after laparotomic nephrectomy: a randomized controlled study.

Abstract

Background: Following laparotomic nephrectomy, regional blocks may improve patients' analgesia profiles. This study aimed to evaluate the effect of the mid-point transverse process to pleura (MTP) block on patients' acute and chronic postoperative pain levels and their need for analgesics after laparotomic nephrectomy.

Methods: Seventy patients of both genders, between the ages of 21and 65 years, categorized as ASA I, II and III by American Society of Anesthesiologists who were scheduled for partial or radical nephrectomy using the standard flank incision approach under general anesthesia were included and randomly assigned into two equal groups; group I (35 patients) received real MTP block with injection of 20 ml 0.5% bupivacaine plus 4 mg (1 mL) dexamethasone whereas group II (35 patients) received sham MTP block (2ml saline subcutaneous). The primary outcome was the postoperative NRS score. Secondary outcomes were morphine consumption on the first day after surgery, the onset of postoperative analgesic request, intraoperative fentanyl consumption, the incidence of perioperative complications, and chronic pain development three months following surgery.

Results: At 30 minutes, 2, 4, 6, 8, 12, and 18 hours after surgery, the patients who received real US-guided MTP block reported significantly lower NRS pain scores. They also consumed significantly less morphine at 24 hours postoperatively, with a median IQR of 9 [6-9] mg, compared to 15 [12-15] mg in the control group. Also, the MTP block group had significantly prolonged analgesic request onset compared to the control group (P=0.000). Additionally, intraoperative fentanyl requirements were significantly reduced by MTP block (P=0.000). Three months following surgery, 40% of patients had developed chronic post-nephrectomy pain, in the control group compared to 17% of patients in the MTP block group (P=0.034).

Conclusions: The preemptive US-guided MTP block improved analgesia quality, reduced the need for rescue analgesia, and provided safe and effective postoperative analgesia with no major side effects, including a lower incidence of chronic post-nephrectomy pain.