US-Guided Lateral Abdominal Wall Botulinum Toxin Injection before Ventral Hernia Repair

Background: The repair of complex ventral hernias (CVH) poses a challenge to the general surgeon. Large hernia defects, loss of domain (LD), multiple previous operative repairs, and associated patient comorbidities can result in increased morbidity and high recurrence rates. Preoperative ultrasound-guided lateral abdominal wall botulinum toxin injection is a promising method for improving patient outcomes and reducing recurrence rates after ventral hernia repair. As radiologists may be increasingly asked to perform ultrasound-guided botulinum toxin injections of the lateral abdominal wall, familiarity with the procedure and current literature is necessary.

Educational Points: A new adjunct option to help deal with such a patient population with ventral hernias has been the use of botulin toxin type A (BTA). This neurotoxic agent blocks the release of acetylcholine from peripheral cholinergic nerve terminals inducing muscle paralysis. Preoperative chemo-denervation of the abdominal wall muscles with BTA allows for fascial approximation, often reducing the need for additional surgical myofascial release due to the thinning and lengthening of the abdominal wall musculature achieved with BTA. The increased compliance of the abdominal wall achieved with the use of BTA may reduce the potential risks of abdominal compartment syndrome, ventilatory restriction, and prolonged ileus among other described complications related to increased intrabdominal pressures. CVH is defined by one or more of the following criteria stratified by defect size (>8 cm in width) with or without LD (loss of domain) plus one or more of the following criteria: laterality (lumbar, lateral and subcostal locations), presence of a parastomal hernia, wound classes III (contaminated) and IV (dirty/infected) (CDC wound classification system) and the condition of the soft tissues (full-thickness abdominal wall defects, loss of substance, denervated muscles, skin grafts, ulcers, open abdomen and other hernia conditions including significantly affected soft tissue). We utilize 200 units of Botox (diluting 200U in 30 mL of normal saline)5. Under ultrasonography (US) guidance in the plane between the internal oblique and transversus abdominis muscles, approximately 5 mL of BTA is injected over three points on each side of the abdominal wall between the anterior axillary line and the midclavicular line, and between the costal margin, and the superior iliac crest. Every injection site is confirmed with saline injection “bubble sign” on US. Primary fascial closure achieved in all cases after 4 to 6 weeks from the injection. - Chemo-denervation with BTA is an off-label use of the product prior to abdominal wall reconstruction to achieve temporary muscle paralysis. It allows for the reduction of the size of the hernia defect as well as thinning and lengthening of the abdominal wall musculature with partial reduction of the hernia sac contents into the abdominal cavity. These effects facilitate fascial closure and in some cases, can obviate the need for additional myofascial release15. Thus, maintaining virgin planes for future repair in case of a recurrence. Different BTA injection protocols have been reported with doses varying from 500U with five injections per laterality, 300U with three injections per laterality, or 200U with three injections per laterality.

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Artikel online veröffentlicht:
02. April 2024