Uterine Myometrium Botulinum Toxin A (BTX) Injections.
The principle is similar to that proposed for BTX injections in the bladder detrusor under cystoscopy for OAB.
The BTX units are evenly distributed in the anterior and posterior myometrial wall under hysteroscopic control.
In 2018, we conducted a prospective feasibility study on 30 patients with severe dysmenorrhoea. The technique and results were presented at the International Neurotoxin Association - INA’s 2019 International Toxins Conference (34) and at the ”Convergences PP” annual congress in Madrid in November 2019 (35).
Uterine myometrial BTX injections are performed under hysteroscopy as an outpatient procedure using a short-term general anaesthetic. The 5 mm Bettocchi type hysteroscope has an operating channel for the needle to pass through.
The effective dose used in this study was 200 IU of BTX, Incobotulinum-toxin A.
The 200 IU of BTX is diluted in saline and evenly distributed in the uterine myometrium with 10 injections in each anterior and posterior muscle wall under hysteroscopic control (figure 1).
All patients fulfilled the PUS criteria and ranged from 17 to 44 years old.
Severe dysmenorrhoea was found in 24 of the patients (89%), all patients had a painful uterine trigger at vaginal examination and 2 patients had deep dyspareunia as the main symptom.
A pelvic ultrasound and MRI ruled out pelvic pathology and endometriosis.
All patients had already received initial treatment such as painkillers, anti-inflammatory drugs, the contraceptive pill, and menstrual suppressant therapy.
Pregnancy was contraindicated during the 4 months following the injection.
Patients were reviewed at 8 weeks, 12 weeks, and 6 months.
They were then assessed on the level of pain using the Visual Analogue Scale (VAS) and the Quality of Life Questionnaire, using the Medical Outcomes Study SF-36 (MOS SF-36), validated in French. All patients were screened for co-morbidities and central pelvic hypersensitivity criteria using the Convergences PP criteria (36).
In terms of statistical analyses, the pre and post-treatment groups were compared using the Freidman test for multiple, dependant non-parametric data. P-values were two tailed and significance was set at the 5% level.