In recent years, ultrasound-guided injection of botulinum toxin A (botox) has emerged as an invaluable method for providing targeted therapeutic paralysis of select muscles.

An increasingly common usage for botox for temporary muscle paralysis outside of the realm of cosmetics is within the lateral abdominal wall muscles prior to ventral hernia repair surgery.  Surgical management of ventral hernias can be challenging, with high morbidity rates as well as high rates of hernia recurrence even with laparoscopic techniques.  Chronic lateral abdominal wall muscular contraction and retraction contributes significantly to challenges associated with ventral hernia repair. Preoperative ultrasound-guided injection of botox into the lateral abdominal wall musculature has recently emerged as a potential method for improving patient outcomes, by achieving relaxation and lengthening of the external oblique, internal oblique, and transversus abdominis muscles prior to surgery. One prospective study in 56 patients found a mean increase in unstretched lateral abdominal wall length of 4 cm per side, allowing for successful primary closure in all cases.¹ Another similar study found a length gain of 2.8 cm prior to surgery.²  To date, no randomized or case-control studies have been published that evaluate operative outcomes or patient satisfaction after ultrasound-guided preoperative botox injection. However, a meta-analysis of 6 cohort studies found that of 133 patients receiving preoperative injections, 83.5% achieved primary fascial closure, and supplemental component separation technique was needed in 24.1%.³

Another clinical indication for ultrasound-guided intramuscular botox injection is for treatment of muscle spasticity and chronic pain. Muscle spasticity can result from a number of etiologies, including seizure-induced and post-traumatic spasticity. Ultrasound guided botox injection into the muscle of concern leads to localized flaccid paralysis and thereby mitigates symptoms. One placebo-controlled, double-blind study of 47 patients with chronic neck pain found that botox injections reduced pain scores compared to placebo at 2 months.⁴ Similar findings have been demonstrated for chronic neck pain after surgical neck dissection.⁵ Another study of 114 patients found that among patients with clinical decrease in neck or shoulder girdle myofascial pain after an initial botox injection, a second injection 6 weeks later decreased improved pain, headaches, general activity, and sleep compared to placebo injection.⁶

Ultrasound guidance for botox injection allows for accurate muscle targeting and can readily be performed by musculoskeletal radiologists. While botox is a temporary treatment, the injection may be repeated if symptoms recur after 3 months.