Patient recruitment will start after ethical committee approval

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Brief Summary

Peri-operative pain management in patients undergoing kidney transplantation is challenging because of impaired renal function and respiratory complications from opioids (1,2). The pharmacokinetics of many drugs is altered including that of opioids, and therefore, the use of morphine for postoperative analgesia after renal transplantation may result in accumulation of its active metabolite; morphine 6-glucuronide due to renal impairment  and leads to undesirable side effects, including respiratory depression, hypoxia, and even psychosis (3,4,5,6). The use of non-steroidal anti-inflammatory drugs is avoided after renal transplantation because of their potential adverse effects on renal haemodynamics. Administration of neuraxial anaesthesia is controversial due to the likelihood of platelet dysfunction in these patients and surgical time can be prolonged, leading to conversion to general anaesthesia (7,8,9).

Intravenous opioids especially morphine remain the mainstay of analgesia, even though significant accumulation of morphine-6-glucuronide has been observed in transplant patients, despite sufficient primary graft function stopping the need for dialysis after transplantation ⁽¹⁰⁾.

The combination of intercostal and ilioinguinal–hypogastric nerve blockade has been shown to reduce both postoperative pain and opioid consumption after renal transplant, and a small pilot study of transversus abdominis plane (TAP) block and a retrospective review of the use of a continuous TAP block reported similar results (11,12,13).

Transversus abdominis plane block targets the lower six thoracic and first lumbar nerve as they course through the interfascial plane that exists between the transversus abdominis and internal oblique muscles, provides analgesia for procedures involving the abdominal wall. TAP blocks have been used in a number of lower abdominal surgical procedures, with investigators reporting reductions in pain scores and opioid requirements (14,15,16) whereas  Frier et al. found no reduction in opioid consumption  in patients following renal transplantation (17).

Quadratus lumborum (QL) block described by Blanco, is a recently introduced variation of TAP block, reported to provide excellent post-operative analgesia in; pediatric patients undergoing radical nephrectomy (18), colostomy closure (19), pyeloplasty (20) ,and an adult patient undergoing laparotomy for duodenal tumor excision (21).

In a radiological study, on the posterior approach of TAP block, which has been described now as the QL block, has shown the spread of the dye and local anaesthetic from T4-L1 (22). QL is an extension of TAP block toward the dorsal region. The US-guided TAP block has the limitation of requiring two levels of block to cover incisions above and below the umbilicus (23). QL block in has an advantage of covering all the dermatome from L2 caudally to T4 cranially as the drug is expected to spread cranially to the higher paravertebral spaces (22).

Carney et al (22), described that the contrast solution placed posteriorly accumulates near the lateral border of the QL and then spreads in a posterior-cranial fashion to the anterior aspect of the QL and psoas major to lie at the paravertebral space. They also obseved the contrast enhancement from T4-L2 level. Similar spread of contrast with a single bolus to cover the incisions above and below the umblicus has been demonstrated by McDonnell et al  (16).

There are no studies in the literature evaluating the analgesic efficacy of quadratus lumborum block for abdominal and renal transplant surgery. This study has been designed to compare the perioperative analgesic efficacy of continuous quadratus lumborum block with the continuous TAP block in a patients scheduled for renal transplant surgery.

We hypothesized that a preincisional continuous quadratus lumborum (QL) block will provide a better perioperative analgesia as compared to continuous transeversus abdominis plane (TAP) block and reduced opioid consumption in the postoperative period in patients undergoing renal transplant.