Injection With OnabotulinumtoxinA (Botox) for the Treatment of Chronic Pelvic Pain
Condition: Myofascial Pain Syndromes; Myofascial Trigger Point Pain; Trigger Point Pain, Myofascial
MeSH terms: Myofascial Pain Syndromes; Fibromyalgia; Pelvic Pain
Study type: Interventional
Phase: Phase 1

Summary: 
      This research study because is looking at woman with symptoms of chronic pelvic pain caused
      by short, tight, and tender pelvic floor muscles (Myofascial Pelvic Pain syndrome). The
      purpose of this study is to determine whether or not injections with onabotulinumtoxinA
      (Botox) improve symptoms of pain and tenderness. The drug being studied, Botox is FDA
      approved for other uses. However, Botox is not FDA approved for the use in myofascial pelvic
      pain (MPP). Therefore, Botox is considered experimental or research in this study.
    

Detailed description: 
      BACKGROUND AND RATIONALE: Chronic pelvic pain affects 15-20% of the female population aged
      18-50 years and accounts for up to 10% of gynecologic visits each year resulting in a cost of
      2.8 billion dollars annually to the health care system. It is defined as non-menstrual
      (non-cyclic) pain that occurs on an average of two weeks per month for at least six months'
      duration; localized to the anatomic pelvis, anterior abdominal wall below the umbilicus,
      buttocks, or lumbosacral back. Many affected patients are noted to have severely short and
      tight pelvic floor muscles on examination (termed MPP), resulting in pelvic floor trigger
      points which may cause associated pelvic symptoms, including: dyspareunia, urinary urgency
      and frequency, symptoms of a urinary tract infection, and pelvic discomfort or heaviness.As a
      result of the constant, severe pain and associated symptoms, women with chronic pelvic pain
      are more likely to experience a decrease in their quality of life, depression, and anxiety
      towards their condition. The difficulty in treating chronic pelvic pain is that the etiology
      can be varied and multifactorial. Frequently associated with an abnormal response to an acute
      injury such as a pelvic infection, traumatic birth, and endometriosis or repetitive insult
      like chronic constipation, chronic pelvic pain can also result from prolonged pelvic floor
      muscle spasm and muscular hypertonicity. Specialized examination of the pelvic floor
      musculature in patients with chronic pelvic pain will often reveal MPP as well as 'trigger
      points'.11 This pain is perpetuated as a result of modifications in the neuronal pathways
      which maintain a set pattern of pain sensations including increased pain sensitivity
      (hyperalgesia), referred pain, and even changes in tissue make-up. The treatment of MPP must
      therefore treat the inciting injury and modify the tissue response. The effects of
      onabotulinumtoxinA on painful muscle were first suggested by the effects of toxin injection
      in patients with migraine headache. While undergoing onabotulinumtoxinA injection for
      cosmetic purposes, patients also suffering from migraine headaches found symptom improvement.
      Further follow-up studies demonstrated a 51% complete resolution and 38% a partial response
      noted of migraine symptoms within in 1 to 2 hours of treatment among true migraine patients.
      Although the mechanism of action remains unclear, onabotulinumtoxinA is believed to act by
      denervating autonomic nerves, thereby altering peripheral sensory nerve function and
      interrupting the migraine cycle of pain. The trigeminal neurovascular theory of migraine pain
      suggests that onabotulinumtoxinA acts not only causing muscle paralysis, but also inhibiting
      the transmission of any vesicles from the synaptic junction, including vasoactive intestinal
      peptide. This blockage of any neuromuscular junction transmission inhibits any muscle
      activity or efferent pain signals. Interestingly, though muscle paralysis takes about one
      week to manifest, pain relief occurs in 1 to 2 hours and although flaccid paralysis last for
      approximately 3 months, benefits for migraine pain last much longer.

      STUDY RATIONALE: In MPP syndrome, prolonged muscle contraction, spasm, and inappropriately
      high muscle tone are thought to diminish blood supply and increase oxygen demand of the
      muscles of the pelvic floor. Ischemic muscle may secrete pain-producing substances, which
      further sensitize muscle nociceptors, alter receptor field properties, and convert wide-band
      mechanoreceptors to nociceptors. OnabotulinumtoxinA can directly block cholinergic
      neuromuscular transmission and interrupt the cascade of events that lead to hyperalgesia and
      allodynia. onabotulinumtoxinA plays a direct role by blocking the alpha- and gamma-motor
      neurons, thereby preventing the abnormal pattern of muscle contraction (eg, spasm, dystonia)
      that activates muscle nociceptors and sensitizes the muscle pain system through mediators.The
      investigators division has been utilizing pelvic floor injections of onabotulinumtoxinA as an
      off-label treatment for MPP in conjunction with pelvic floor physical therapy for more than 6
      years. In patients with severe MPP, who often unable to tolerate any vaginal exam, or those
      receiving no further reduction in pelvic pain with extensive physical therapy, the
      investigators have been utilizing the injection of 100 U of onabotulinumtoxinA into pelvic
      floor trigger points with significant success. Anecdotally, treated patients report a 30-40%
      reduction in their pain complaints 7-10 days post-treatment which lasts for approximately 3
      months. Even when the pain recurs, it is not as severe as it was pre-treatment and patients
      take the opportunity of the window of reduced pain to maximize further progress with pelvic
      floor physical therapy. Two to four weeks after pelvic floor injection, patients with severe
      MPP reported statistically significant changes in VAS scores before and after
      onabotulinumtoxinA treatment with a median reduction in VAS of -3.9 (CI for changed score
      -2.2, -5.6, p<0.001). Eighty percent of patients reported significant subjective improvement
      in their pelvic pain lasting more than 4 weeks and anecdotally lasting up to 3 to 4 months in
      duration. Adverse events were reported by 22% of patients and were mild, limited to: pelvic
      heaviness, increased pain, urinary irritation, and nausea/vomiting. However, despite these
      encouraging results, there is no definitive evidence that onabotulinumtoxinA is an effective
      treatment modality in patients with severe MPP. In their evidence-based review of the
      literature regarding the treatment of refractory pain with onabotulinumtoxinA, Jabbari and
      Machado found only level C evidence (possibly effective, may be used at discretion of
      clinician) when investigated the role of onabotulinumtoxinAs in the treatment of MPP.
      Moreover, less is known regarding the potential side effects of onabotulinumtoxinA injected
      into the pelvic floor muscles. Therefore, stronger randomized controlled studies are
      necessary to investigate the efficacy and possible side effects of pelvic floor injections of
      onabotulinumtoxinA in the treatment of MPP syndrome and this is actually our research
      proposal. It is our hope that our study will significantly change current clinical treatment
      protocols for MPP syndrome.

      STUDY DESIGN: This is a phase I study in which participants will be randomized 1:1
      (onabotulinumtoxinA:placebo), double-blinded, placebo-controlled clinical trial. Potential
      participants are women seeking treatment for MPP as diagnosed by the participating clinical
      investigators based on the following criteria: MPP is defined by at least 4 to 5 palpable
      trigger points on transvaginal and/or transrectal examination of the pelvic floor, which
      reproduces the pain for which they are seeking medical care. A trigger point is defined as an
      extremely tender focus of muscle causing pain radiating to other areas specific for each
      trigger point. A trigger point is termed 'active' if pain occurs spontaneously, and 'latent'
      if palpation and pressure are required to elicit pain, which may replicate symptoms or
      radiate to surrounding lower extremity, pelvic and abdominal sites. This study will have two
      arms:* Treatment group: 20 patients randomly assigned to receive 100 U onabotulinumtoxinA
      reconstituted in 20 ml saline sequentially injected bilaterally into the pubococcygeus,
      iliococcygeus, coccygeus, obturator internus, and piriformis muscles. * Placebo group: 20
      patients randomly assigned to receive 20 ml of saline bilaterally into the same pelvic floor
      muscles. All injections will be performed using a pudendal injection tray in the clinical
      treatment area after obtaining consent. The patients will be randomized using a
      computer-generated randomization sequences in balanced blocks of four. Both the patients and
      physicians will be blinded to the first injection assignment. All participants with
      inadequate symptom control (VAS score 7 or more) at 1 months after the injection will have
      their treatment unblinded. Those who received placebo (saline) will be offered injection with
      open label onabotlulinumA. Those who previously received onabotlulinumA will not be eligible
      for reinjection. All patients will be followed for 6 months after the initial injection or
      for 6 months following the second injection. All patients who opt for a second injection will
      once again begin the outlined injection follow-up visit schedule.

      STUDY PROCEDURES:

      Screening - A detailed medical and surgical history, demographic information and review of
      medications will be taken from all patients suspected of having MPP. Then, a physical exam
      and a pelvic floor examination for myofascial trigger points will be performed. It will
      include an assessment of VAS at the bilateral pubococcygeus, iliococcygeus, coccygeus,
      obturator internus, and piriformis muscles. All VAS scores will be recorded. Post residual
      Void (PVR) will be recorded. Patients will have an assessment of their post residual void
      (PVR) and the volume will be recorded. Patients who meet inclusion criteria will be offered
      study participation. Patients who agree to participate will be formally consented and
      complete all pertinent questionnaires: * Short Form 12 (SF-12) for quality of life assessment
      * Patient Global Impression Index (PGI-I) for degree of bother from pelvic pain * Pelvic
      Floor Distress Inventory (PFDI) and Pelvic Floor Impact Questionnaire (PFIQ - short form 7)
      to assess the bladder and bowel functions * Female Sexual Function Index (FSFI) for sexual
      function assessment. Currently no validated questionnaire for symptoms of MPP exists.

      Procedure - A pudendal block type needle is gently advanced along the outstretched fingers.
      Holding the needle in a near horizontal plane, the pelvic floor muscles are injected in a
      systematic fashion starting on the levator ani and then marching backward all the way down
      back to the piriformis muscle including the obturator internus muscle. The following muscles
      are sequentially injected with 2 cc of diluted onabotulinumtoxinA: pubococcygeus (this muscle
      is felt as a sling around the vagina, just proximal to the hymenal ring), iliococcygeus
      (palpated superiorly and laterally to pubococcygeus muscle), obturator internus (on the
      sidewalls of the pelvis just superior to the arcus tendineus levator ani), coccygeus (half
      distance between the ischial spine and sacrum), and piriformis (these muscles are palpated
      filling the posterolateral pelvic walls and are injected lateral to the sacrum). Careful
      attention is made to withdraw prior to injection to ensure no intravascular injection of the
      diluted onabotulinumtoxinA. Once the injection had been performed on one side of the pelvis,
      pressure is held for good hemostasis. The same procedure is then performed on the other side.
      Peri-procedural adverse events are recorded.

      Post Procedure Instructions - Post treatment, all patients will be monitored for 15 minutes.
      Standardized post-injection instructions are given to the participant verbally and in written
      form. Patients will be contacted by telephone within 24-48 hours after the procedure for
      safety assessment. The first follow-up evaluation will be scheduled 1 month after pelvic
      floor injection.

      Follow-Up Visits 3, 4, 5, 6, 7 & Visit 8 (Visit 8, only if Patient Received 2nd Injection) -
      Follow-up clinic evaluations will occur 1, 2, 3, 4 and 6 months after injection,
      respectively. A history will be taken and a physical examination that includes PVR assessment
      will be performed at each follow-up visit. VAS scores of pelvic floor muscles will be
      recorded. PGI-I, PFDI, PFIQ, and FSFI forms will be collected at each follow-up visit.
      Adverse events will be carefully monitored and recorded.
    

Intervention name(s): OnabotulinumtoxinA; Placebo
Intervention type(s): Drug; Drug
Intervention description(s): comparison of OnabotulinumtoxinA with placebo; comparison of placebo with investigational drug OnabotulinumtoxinA
Other intervention name(s): Botox
Intervention MeSH terms: Botulinum Toxins, Type A; abobotulinumtoxinA
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Treatment
Keywords: Myofascial Pain Syndromes; Pelvic pain; Trigger points + injections; Myofascial Trigger Point Pain; Trigger Point Pain, Myofascial; Botulinum Toxins, Type A; Botulinum Neurotoxin A; Botulinum Toxin Type A; Clostridium botulinum A Toxin; Clostridium Botulinum Toxin Type A; Oculinum