Chronic pelvic pain syndrome (CPPS) is the perception of pain in pelvic-related structures with associated lower urinary tract, sexual, bowel or gynecological dysfunction for 6 months or more. It affects approximately, up to 78% in women with interstitial cystitis.
Its etiology includes gynecological, urological, gastrointestinal, neuropathic and musculoskeletal pathology, which makes the existence of multidisciplinary groups essential for a correct treatment.
Myofascial pelvic pain alludes to pain of the pelvic floor muscles (PFM) and connecting fascia. This syndrome can present on itself, without concomitant medical pathology, or it may exist as a precursor or sequel to urologic, gynecologic, and colorectal medical conditions, as well as other neuro-musculoskeletal pathology. The hallmark diagnostic indicator of myofascial pelvic pain syndrome is the presence of myofascial trigger points in the pelvic floor muscles. This pain can be refered in many areas, including the suprapubic region, lower abdomen, posterior and inner thighs, buttocks, and lower back. These myofascial trigger points are located within hypersensitive tight bands within the muscles, which will elicit a referred pain pattern associated with that palpation that is specific to each muscle. 
Rehabilitation treatment is key pillar in these patients’ management. Depending on the assessment of the musculoskeletal dysfunction, a handful of options are available: manual techniques, correction of biomechanical alterations, muscle re-education, electrostimulation and lifestyle modifications, among others.
Interventional procedures have an important role in the diagnosis and/or treatment of CPD. Its main objective is the inactivation of trigger points, thus reducing pain and restoring muscle function. Among them we find transvaginal infiltration of botulinum toxin A (BTX/A), with statistically significant results in the reduction of pelvic pain, pelvic floor pressure and dyspareunia. BTX/A has a dual mechanism of action.  It allows muscle relaxation induced by the release of acetylcholine at the neuromuscular junction. Once injected, BXT/A enters the nerve termination of motor neurons in the presynaptic membrane and blocks the release of acetylcholine, causing a relaxation that usually lasts 3 to 6 months. It also produces a direct antinociceptive effect, blocking the release of local neurotransmitters involved in pain signaling. This las effect occurs earlier than the muscle relaxation. This dual mode of action makes BTX/A a very attractive tool for treating many painful pelvic floor disorders and clinical experience also supports its use.
To describe the results of treatment with botulinum toxin infiltration in women with pelvic pain, refractory to previous rehabilitation treatments.

We conducted a descriptive cross-sectional study including women with chronic pelvic pain refractory to previous rehabilitation treatments, both conservative (manual techniques, correction of biomechanical alterations, muscle re-education, electrostimulation, therapeutic exercise, aerobic conditioning and lifestyle modifications) and invasive (dry needling and corticosteroid infiltration) attended in the rehabilitation department of a tertiary hospital from January 2022 to December 2023.
A review of electronic medical records included 29 women diagnosed with refractory chronic pelvic pain, who underwent infiltration with botulinum toxin (Incobotulinumtoxin A) as a compassionate use, with periodic post-infiltration check-ups. 
A clinical assessment protocol was applied. It included sociodemographic data (sex, age, parity), cause of pain, time of pain in years, previous treatments, toxin doses, reinfiltrations and complications.
Visual analog scale (VAS) was used as a review tool before and after each intervention.

Twenty-nine female patients were evaluated, with a mean age of 45.79 years.
The mean time of pain was 2.66 years, starting from an initial mean VAS of 7.90.
The following pain triggers were found: 6 postpartum, 6 postmenopausal, 5 onset of sexual intercourse, 6 post-surgical and in 4 of them no cause was found.
Regarding the previous treatments performed, 7 patients received combined treatment (rehabilitation treatment + dry needling + corticosteroid infiltrations), 4 patients received physiotherapy treatment (manual +/- dry needling), 12 patients received corticosteroid infiltrations and 6 patients received rehabilitation treatment + corticosteroid infiltrations.
The mean dose of botulinum toxin used was 84.4 IU, distrubuted in 1 to 3 spots. 
The infiltrated muscles were iliococcygeus in 13 patients, puborectal in 10 patients and pubovaginal in 1 patient (2 of the patients being a combination of the three muscles), 12 patients in introitus (6 only in introitus and 6 combined with other muscles) and 2 patients in episiotomy (1 in scar and another patient combined).
One month after infiltration the mean VAS was reduced by almost 50% (3.54 with SD 2.84) being this result statistically significant (p<0.001) measured with Student's t-test.
In 4 cases no improvement was found.  
Five patients required a new infiltration in the following 3 to 6 months.
No complications related to the technique or BTX/A were found.

The benefit of BTX/A use as a treatment for chronic refractory pelvic pain has been demonstrated. This technique is useful, effective and safe.
Studies with a larger sample size, as well as including a control group should be developed.

Pelvic floor muscle infiltration with BTX/A, should be considered as a complementary therapeutic option to the usual physiotherapy treatment.

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