The use of ultrasound-guided transversus abdominis plane block (TAPb) in combination with general anesthesia during robotic partial nephrectomy may improve postoperative morphine consumption, the intensity of acute somatic pain, and the incidence of chronic pain but not acute visceral pain, according to a study published in Pain Medicine.

Renal surgery often results in severe postsurgical pain. Locoregional analgesia techniques such as TAPb, which have proven effective in other surgeries, may offer substantial relief.

In this 2-arm parallel prospective randomized trial (Clinicaltrials.gov identifier: NCT02460640), 96 patients age >18 years who were categorized as American Society of Anesthesiologists physical status class I-III and scheduled for robotic partial nephrectomy between June 2015 and August 2017 were enrolled. Participants were randomly assigned to receive standard general anesthesia plus TAPb (TAP group; n=48; mean age, 54.3 years; 62.5% men) or standard general anesthesia alone (NO-TAP; n=48; mean age, 60.2 years; 45.8% men). In the TAPb group, a unilateral double-approach and 30 mL of ropivacaine 0.5% was administered. Participants had access post-surgery to intravenous morphine via patient-controlled analgesia.

The primary outcome of interest was morphine consumption 24 hours post-surgery; secondary outcomes included surgical site hypersensitivity, nausea and vomiting incidence within the first 24 hours, and the incidence of acute and chronic pain evaluated with a 0 to 10 numeric rating scale (NRS) and the Douleur Neuropathique-4 (DN-4) questionnaire.

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At 24 hours after surgery, participants receiving TAPb vs no TAPb consumed less opioid medication (10.6 mg vs 14.1 mg, respectively; P <.008), had lower median pain scores on the NRS with movement (6 vs 7, respectively; P <.001), and lower median NRS somatic pain scores (3 vs 6, respectively; P <.001). Median NRS visceral pain score was 5 in both groups. The area under the curve, calculated to compare the 2 groups, was significant for overall pain at rest (P =.004) and with movement (P =.009), as well as for somatic pain (P <.001), but not visceral pain in the 24 hours after surgery.

Participants who did not vs did receive TAPb had greater postsurgical pain evaluated with DN-4 or NRS at 3 months (P <.001 for both) and 6 months (P =.004 with DN-4 and P =.047 with NRS), but not at 12 months. Postoperative nausea and vomiting in the first 24 hours after surgery were comparable in both groups. There was no difference in preoperative surgical site hypersensitivity between groups.

Study limitations include a small sample size and the lack of sensory measurement after TAPb.

“In the future, specially structured studies will be needed to investigate whether the use of TAPb, in a multimodal therapy regimen, can effectively improve the management of acute and chronic postoperative pain,” noted the authors.

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Reference

Covotta M, Claroni C, Costantini M, et al. The effects of ultrasound-guided transversus abdominis plane block on acute and chronic postsurgical pain after robotic partial nephrectomy: a prospective randomized clinical trial. Pain Med. August 2019:1-9. doi:10.1093/pm/pnz214