CT-guided Pelvic Muscle Botulinum Injections for High-tone Pelvic Floor Dysfunction: A Pictorial Guide

1. Identify indications for pelvic muscle botulinum injection
2. Understand the anatomy of pelvic floor muscles, nerves, and arteries. 
3. Review anatomic considerations while performing injections
4. Review current data regarding efficacy and potential complications



Background:

High-tone pelvic floor dysfunction (HT-PFD) is an underrecognized and undertreated component of chronic pelvic pain (CPP). Twenty-three percent of patients with CPP have associated HT-PFD {1}. While often deemed idiopathic, the condition may result as the sequela to a gynecologic, urologic, or colorectal medical condition {2}. Treatment options include pelvic physiotherapy, biofeedback, and neuropathic pain modulators. In patients who have failed conservative therapy, botulinum toxin injections into the pelvic floor muscles has emerged as an adjunct treatment. A recent meta-analysis showed botulinum toxin therapy is the most highly efficacious option for long-term pain control in these patients {3}.  

 

Clinical Findings/Procedure Details:

To perform pelvic muscle botulinum injections, patients are positioned prone and sedated. The procedure is executed under CT guidance. An initial planning CT is obtained and the bilateral piriformis muscles, obturator muscles, and levator ani muscles are marked. A 23 Gauge x 15 cm Chiba needle is then placed into each muscle, for a total of 6 needles. Often this procedure is paired with a pudendal nerve block, in which case a 22 Gauge x 15 cm Chiba needle is placed in each pudendal canal. Once all needles are placed, 300U of Botulinum toxin A is injected, divided among the 6 muscles. The pudendal nerves are each treated with 5 ml of 0.5% bupivacaine and 40mg triamcinolone.

 

Conclusion and/or Teaching Points:

Pelvic muscle botulinum injections are an effective tool in the management of HT-PFD with high efficacy in the appropriate patient and favorable complication profile. The procedure is straightforward with high technical success given understanding of possible pitfalls.