Title: Quadratus Lumborum Versus Transversus Abdominis Plane Nerve Blocks for Pediatric Renal Transplantation: A Retrospective Study

Introduction: 

• Effective pain management following pediatric renal transplantation is challenging. 
• There is a paucity of evidence for the use of peripheral regional anesthesia. 
• QL and TAP blocks have been used for adult renal transplantation analgesia.
• This retrospective study evaluated the effectiveness of QL blocks and TAP blocks in pediatric renal transplantation. 
  • Primary outcome: Postoperative opioid consumption measured in morphine milligram equivalents (MME)
  • Secondary outcome: Time to extubation
• We hypothesize that QL blocks will be more effective in reducing postoperative opioid consumption in the first 24 hours following pediatric renal transplantation. 

Methods: 

• Following IRB exemption, a retrospective chart review was conducted on all patients under 21 years of age undergoing renal transplantation at a single academic pediatric hospital from 2019 to 2023. 
• Exclusion criteria included weight less than 15 kg and chronic pain.
• A total of 108 patients undergoing kidney transplant surgery were divided into one of four categories:
  • Unilateral QL block with contralateral rectus sheath (RS) block [QL group]
  • “High-dose” unilateral TAP block where the weight-based local  anesthetic administered exceeded 40% of the patient’s maximum allowable local anesthetic mass in milligrams  [hTAP group]
  • “Low-dose” unilateral TAP [lTAP group]
  • No block group
  • All blocks were single injections without the use of any adjuvants. 

Results: 

Demographics for the 4 groups (Table 1) were similar except for a greater average weight in the lTAP group. The QL group had significantly reduced opioid consumption on POD 0 as compared to the no block group (p=0.03), but not on POD 1 (Table 2). Comparisons between all other groups did not yield any differences in opioid consumption for either POD 0 or POD 1. All patients in the QL group were extubated in the operating room, hence demonstrating the shortest extubation times (p=0.001) (Table 3). 

Discussion: 

• This study provides a direct comparison between QL and TAP blocks for postoperative analgesia following pediatric renal transplantation. 
• Patients who received nerve blocks showed a tendency toward reduced opioid consumption on POD 0.  
• The group with the QL block was the only one to exhibit significantly lower opioid consumption on POD 0. 
• The trend toward higher opioid consumption on POD 1 may suggest a type of rebound effect in the QL group. 
• All groups had similar opioid requirements on POD 1 presumably due to block resolution. Although the QL group had the shortest extubation times, multiple factors outside of pain control likely contributed to the extubation times.