Rodrigo Tomazini Martins3, John Read1, Christian Skulina2, Dominic Rowe2, Kristen Elstner3, Fernando Arduini3, Nabeel Ibrahim4. 1Macquarie University Hospital, Radiology department, Sydney, Australia, 2Macquarie University Hospital, Neurology department, Sydney, Australia, 3Australia Hernia Centre, Edgecliff, Sydney, Australia, 4Macquarie University Hospital, Surgery department, Sydney, Australia
Introduction: BTA injection of the lateral obliques has been shown to produce a prolonged flaccid muscle elongation which enables closure of hernia defects under minimal tension. Post-operatively, this reduction in tension on the wound has been hypothesized to protect the repair during the critical initial phase of wound healing. This is particularly useful in patients with high risk of recurrence, and raises the question if BTA paralysis and the reduced wound tension is beneficial to post-operative healing. However, the duration of BTA effect in this setting remains unknown, and no data currently exists as to the timing of any subsequent BTA top-up injections intended to prolong the overall period of muscle paralysis. This prospective study aimed to examine the duration BTA effect administered in the setting of ventral hernia repair.
Methods and Procedures: Preoperative accurate ultrasound guided BTA infiltration of the lateral obliques occurred in 49 patients. All patients underwent serial abdominal CT imaging at baseline, post-BTA, and post-operative. Post-operative CT imaging is used to examine the integrity of hernia repair and to evaluate the residual paralysis at 3-4 months after initial BTA administration. CT imaging can demonstrate residual BTA effect by comparing muscle length and thickness with previous imaging. In 10 patients considered to be at high risk of recurrence, electromyography (EMG) assessment was also performed on the same day as their post-operative CT imaging. This cohort was composed of 8 males and 2 females, mean age of 63 years, and mean BMI=29.8kg/m2. The mean interval between BTA injections and surgery was 16.5 days and the mean interval between BTA injection and EMG assessment was 143 days. EMG was performed under real time ultrasound, bilaterally, during rest and straining maneuvers, with the aim to quantitatively measure muscle activity in the lateral obliques.
Results: EMG studied individual muscle and demonstrated small to moderate voluntary activity in most muscle layers at the time of assessment. This is similar to CT changes that were noted at the same time, confirming a reduction in BTA induced paralysis. EMG performed during strain better demonstrated return of muscle activity from day 143, however it was evidenced muscle activity recovery from day 99.
Conclusions: EMG assessment can provide a more sensitive and reliable quantification of residual BTA paralysis and potentially guide the timing of post-operative BTA top-up doses, no later than 3 months, eliminating the use of CT for this purpose and thereby reducing radiation exposure.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 79514
Program Number: P036
Presentation Session: Poster (Non CME)
Presentation Type: Poster