Botulinum Toxin for Pelvic Pain in Women With Endometriosis

Background:

- Some women with endometriosis have chronic pelvic pain. This pain may be caused by spasms of the pelvic floor muscles. These spasms can be detected by an examination. Studies suggest that botulinum toxin can help treat problems caused by muscle spasms. Researchers want to see if botulinum toxin injections into the pelvic floor muscles can decrease pain and spasms in women with pelvic pain.

Objectives:

- To see if botulinum toxin can relieve pain from pelvic floor spasm in women with pelvic pain.

Eligibility:

- Women between 18 and 50 years of age with pain associated with pelvic muscle spasm and endometriosis. Pain must be persistent (lasting for at least 3 months).

Design:

• Participants will keep a pain diary and record their pain medication use for a month before the first visit.
• Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. Participants will also answer questions about their pain levels and quality of life.
• Participants will receive either botulinum toxin or a placebo (salt water) injection. The injection will be given into the pelvic floor muscles through the vaginal wall. Participants will take a muscle relaxant like Valium and have anesthetic cream put on the vaginal wall before the injection.
• After the injection, participants will keep a pain diary for another month.
• At a 1-month followup visit, participants will answer questions about their pain. If the pain has not improved, all participants may have a botulinum toxin injection (no placebo) into the pelvic floor muscles as before.
• Participants will have followup visits for up to a year after the initial 1-month followup visit.

Chronic pelvic pain associated with endometriosis is poorly understood. Some women with chronic pelvic pain have muscle spasm of their pelvic muscles. Muscle spasm may be a significant part of pain in women with endometriosis and other types of chronic pelvic pain. Botulinum toxin injection is widely used to treat conditions associated with excessive muscle activity and spasm. Studies of botulinum toxin injected into pelvic muscles of women with pelvic pain have shown a decrease pain and spasm, but too few women have been studied to conclude its effectiveness. We expect to show that botulinum toxin injection in women with pelvic pain will relieve some of their pelvic pain.

Eligible subjects will be otherwise healthy women who have chronic pelvic pain and a history of endometriosis. Subjects will be randomized to either botulinum toxin injection or placebo (salt water) injection. After one month, we will evaluate the presence of the pain and all women will be offered botulinum toxin injection. We will also evaluate the need for reinjection.

• Endometriosis
• Botulinum Toxin A
• Chronic Pelvic Pain
• Pelvic Muscle Spasms
• Quality of Life

• Abbott JA, Jarvis SK, Lyons SD, Thomson A, Vancaille TG. Botulinum toxin type A for chronic pain and pelvic floor spasm in women: a randomized controlled trial. Obstet Gynecol. 2006 Oct;108(4):915-23.
• Bhidayasiri R, Truong DD. Expanding use of botulinum toxin. J Neurol Sci. 2005 Aug 15;235(1-2):1-9. Review.
• Jankovic J. Botulinum toxin in clinical practice. J Neurol Neurosurg Psychiatry. 2004 Jul;75(7):951-7. Review.

• INCLUSION CRITERIA:
• Female gender
• Age between 18 and 50
• History of endometriosis at surgery
• Persistent pelvic pain for at least 3 months
• Pelvic floor spasm
• Negative pregnancy test
• Willing to use reliable method of contraception for the month after botulinum toxin injection
• Willing and able to give informed consent
• Willing and able to comply with study requirements

EXCLUSION CRITERIA:

• Women with other causes of chronic pelvic pain including infectious, gastrointestinal, psychological disorders, fibromyalgia and chronic fatigue syndrome
• Untreated severe cervical dysplasia or other gynecologic condition
• Significant abnormalities in the physical or laboratory examination including renal and liver function more than twice the normal range
• Hysterectomy and bilateral salpingo-oophorectomy
• Pregnancy
• Lactation
• Allergy to albumen or botulinum toxin
• Presence of antibodies to botulinum toxin or loss of response to previous injections for any indication
• A known neuromuscular junction disorder such as myasthenia gravis or Eaton-Lambert syndrome
• History of urinary or fecal incontinence
• Known pelvic prolapse