Transversus Abdominis Plane Block in Iliac Crest harvest-is it Beneficial?

This study is a prospective, randomised, parallel group, single - centre trial evaluating the postoperative parameters in patients receiving supplemental Transversus Abdominis Plane block for anterior iliac crest harvest. It was conducted in 143 patients undergoing Alveolar bone grafting with iliac crest bone graft.

Methodology:

Informed consent and approval of local ethics and research committee in Jubilee Mission Medical College and Research Institute, Thrissur, India was obtained prior to initiation of the study. A pilot study was done to determine the efficacy of the additional TAP block. The results showed that the intervention improved patient analgesia and reduced the requirement for rescue analgesics. A minimum sample size of 65 patients was calculated for each group to obtain a power of 80% and confidence interval of 95%. 143 patients aged between 7 and 22 years posted for Alveolar bone grafting with anterior iliac crest harvest were assessed in the study. Only those undergoing Alveolar bone grafting as a part of the reconstructive procedure for cleft lip and palate were considered for the study. The patients who had difficulty in mentation and communication,bleeding disorders, hepatic problems, infection of the abdominal wall, renal dysfunction as well as allergy to the local anaesthetic were excluded from the study. Patients undergoing revision surgeries were also excluded from the study. All the candidates were randomly alloted to either of the two groups, using a computer - generated number.

All the patients were premedicated with Midazolam 0.15mg kg-1 and Glycopyrolate 0.01mg kg-1 Anaesthesia was induced with Propofol 2 mg kg -1 and Fentanyl 2 mcg kg-1 .Vecuronium 0.1 mg kg-1 was given to facilitate orotracheal intubation with a cuffed tube.Anaesthesia was maintained with oxygen, nitrous oxide and sevoflurane. Prior to incision, all the patients were given wound infiltration with 0.75 ml kg-1 of 0.2% Ropivacaine at the graft harvest site. Those in group A received an additional ultrasound guided Transversus Abdominis Plane block with a similar volume and concentration of Ropivacaine.

At the end of the surgical procedure, the patients were extubated awake, after giving I / V Neostigmine 0.05 mg kg-1. Just prior to extubation, I/V Tramadol 0.5 mg kg-1 was given for the pain in the postoperative period. In the recovery room, the pain and emergence delirium were assessed by an independent observer every ten minutes during the first postoperative hour.These were evaluated using the FLACC Behavioural Pain Assessment Scale and WATCHA Scale respectively. They were subsequently shifted to the postoperative ward.

The next time point of assessment was 24 hours post - surgery, when the patient's pain and ambulatory status were evaluated. The pain was ranked using the five - point verbal ranking score. It was ranked as no pain, light pain, moderate pain, severe pain and intolerable pain, with a score of 0,1,2,3 and 4 respectively. The total number of rescue analgesics demanded by the patient on the first postoperative day was noted.Ambulatory status was graded using one - day Cumulated Ambulatory Score.

The patients were followed up and questioned at six weeks and twelve weeks post operatively for the presence of chronic pain, numbness or wound healing problems at the harvest site.