Myofascial pelvic pain is a disorder of unclear etiology in which pelvic pain is attributed to short, tight, and tender pelvic floor muscles. Tender points are the hallmark of myofascial pain and are characterized as the painful knots palpated in tender muscles. The majority of patients respond to conservative treatment with transvaginal pelvic floor physical therapy. In the minority of patients with severe symptoms refractory to conservative treatments, onabotulinum A toxin has been reported to significantly improve pelvic pain when injected into the pelvic floor muscles. The toxin acts by inhibiting calcium-mediated release of acetylcholine vesicles at the presynaptic neuromuscular junction in peripheral nerve endings, resulting in temporary flaccid muscle paralysis. It has been shown to decrease pain associated with hypertonic muscles. This video will demonstrate our technique for pelvic floor muscle injection with onabotulinum A toxin to treat myofascial pelvic pain in women. This treatment is easy to perform and generally well tolerated by patients. This treatment is often performed in an office setting with the patient awake as digital muscle palpation offers a better localization of tender and contracted points along the pelvic floor muscles to be injected. Alternatively, some patients choose to undergo the treatment in an outpatient surgery setting for pain or anxiety reasons. In these cases, the trigger points can be previously localized during an office examination and then injected in the operating room with the patient under IV sedation or general anesthesia. In our demonstration, the procedure will be performed in an operating room with the patient under general anesthesia. Procedure supplies include a standard pedendal block kit with a trumpet guide that allows for a depth of one centimeter needle penetration through the vaginal mucosa and into the muscles. One vial or 100 units onabotulinum A toxin. Alternative forms of botulinum toxin are available. 20 cc's of injectable saline and two 10 cc syringes. 100 units of the toxin is reconstituted in 20 cc's of sterile saline. Vial mixing is performed in a swirling manner with caution not to agitate the vial too forcefully resulting in the formation of bubbles or foam as this means the breakdown of toxin molecules. The content of the vial is then transferred into two 10 cc syringes each containing 50 units of onabotulinum A toxin. After anesthesia induction, the patient is placed in dorsal lithotomy position with her legs in stirrups and is prepped and draped in a normal sterile fashion. In this case, examination under anesthesia is entirely normal and the patient's bladder is emptied with a catheter. The pelvic floor muscles on the patient's left side were injected first. The muscles to be injected are easily palpated by digital vaginal exploration using the operator's index and middle fingers. A 20 gauge pedendal block type needle with a trumpet guide is gently advanced along the outstretched fingers. The needle is held in near horizontal plane perpendicular to the pelvic floor muscles. Careful attention is made to aspirate the syringe prior to injection at each site to ensure no intravascular doses are given. This animation demonstrates our technique for systematic injection of the pelvic floor muscles with onabotulinum A toxin. The following muscles are sequentially injected with 2 cc's of diluted botulinum A toxin. Pubococcygeus. This muscle is felt as a sling around the vagina, just proximal to the hymenal ring. Ileococcygeus, palpated superior and laterally to the pubococcygeus muscle. Coccygeus, located halfway between the ischial spine and sacrum. Piriformis. These muscles are palpated filling the posterior lateral pelvic walls and are injected laterally to the sacrum. Lastly, the obturator internus, on the sidewalls of the pelvis, just superior to the arcus tendineus levator anni. Once the injections have been performed on the left side of the pelvis, pressure is held for a few minutes for good hemostasis. The same procedure is then performed on the patient's right side. Upon completion of the procedure, the entire surgical field is once again examined to assure good hemostasis. Post-treatment, all patients are monitored for 15 minutes if the procedure was done in an office setting or 1-2 hours if the procedure was performed in the operating room. This patient tolerated the procedure well and was discharged home in good condition. Pelvic floor injection of onabotulinum A toxin is a straightforward outpatient procedure for women with myofascial pelvic pain syndrome, refractory to pelvic floor physical therapy. This procedure is effective and is well tolerated by patients.

myofascial pelvic pain

pelvic floor muscles

onabotulinum A toxin injections

conservative treatments

muscle tightness