Vesicovaginal fistula (VVF) is an abnormal opening between the vagina and the bladder that occurs often during childbirth as a result of prolonged obstructed labour [1, 2]. This occurs following compression on the pelvis by the foetal head resulting in tissue necrosis. This creates an opening between the vagina and bladder which leads to constant urine leakage from the vagina [1,2,3]. It is the major type of obstetric fistula, accounting for about 90% of all obstetric fistula cases [1, 4]. It is also regarded as one of the major causes of morbidity among females in developing countries and some parts of developed countries [2, 5]. The consequences of VVF can be devastating, as it affects women physically, socially, economically and psychologically [3, 4].
A number of studies have noted the risks for developing VVF as including: illiteracy, poverty or low socio-economic status, childbearing at an early age, lack of access to antenatal care, lack of skilled or trained traditional birth attendants, and a malformed pelvis [3,4,5,6,7,8]. Obstetric VVF affects 2 million women worldwide, with a prevalence of 3 per 1000 women in sub-Saharan Africa [2, 5, 8]. In Nigeria, according to the Federal Ministry of Health , there are over 20,000 new cases of VVF yearly, in addition to the approximately 400,000–800,000 existing cases awaiting surgical repair. Over 85% of all cases of VVF are found in the north-western part of Nigeria [7, 10]; high incidences are reported in Kano, Katsina and Bauchi states in this region of the country .
Surgical interventions have been proven to be the effective management for VVF, especially in complex fistula, and in small fistula if conservative treatment fails [1, 11]. Unfortunately, some women pass through the devastating period of having the VVF and undergoing the surgical procedure, but do not regain continence [1, 12, 13]. The VVF repair may be satisfactory anatomically, but inadequate functionally, as some women present with urinary leakage (called post-fistula repair incontinence) even after a successful repair [12,13,14,15,16].
Post-fistula repair incontinence (PFRI) as reported in the literature, is one of the most common complications of VVF surgeries, where urine continues to leak (especially with exertion) after successful VVF closure [12, 13, 17]. This incontinent gap is poorly understood and is a source of frustration to fistula surgeons (and particularly the patients) [1, 16, 18,19,20].
Risk for developing PFRI depends on the site and type of fistula, as well as pelvic floor strength (PFS). Women with severe pelvic floor muscle (PFM) weakness are at risk of developing PFRI [21, 22]. According to Kayondo et al., type IIb fistulae are six times more likely to cause incontinence after successful repair than type I fistulae . Also, women with circumferential fistula or larg fistulas are less likely to be continent after surgery . PFRI also arises due to small bladder size/capacity following loss of the surface area of the bladder wall due to extensive fistula, neurologic damage, or due to the involvement of the urethral sphincter, especially if there is marked tissue loss and scarring [1, 8, 12]. Furthermore, PFRI occurs if there is loss of the sphincteric mechanism of the vesicourethral junction, and reduced bladder capacity or injury to the urethra [14, 20]. It has been reported that the risk of PFRI is 50% in women with minimal vaginal scarring and good bladder volume, while is 100% in women with reduced bladder volume and/or severe vaginal scarring [22,23,24]. Conservative interventions are the mainstay in the treatment of PFRI [11, 14, 20]; but unfortunately, supplementary surgery is prioritized over non-surgical options; the consequence of this is further deterioration of the condition . It has however, been suggested that surgery should only be considered in persistent cases of PFRI or if the conservative treatment failed [12, 13].
Physiotherapy plays a vital role in the management of urinary incontinence (UI) and its associated symptoms through rehabilitation of the pelvic floor muscles (PFM), either directly or indirectly. Directly, the PFM can be rehabilitated through: pelvic floor muscle training (PFMT), biofeedback, cone therapy, and neuromuscular electrical stimulation [25, 26]; and indirectly through exercising other muscles of the body like the transverse abdominal muscles and circular or ring muscles (known as Paula Exercise Method), and also by patient education [27,28,29]. However, there is limited data on the role of physiotherapy on PFRI specifically. The available data mainly used pelvic floor muscles training (PFMT) [8, 13, 14, 17, 30]. And, to achieve positive effects of the PFMT, the exercise needs to be individualized and performed under professional supervision . In addition, women find it difficult to voluntarily contract their PFM if it is weak even with proper instructions, and instead they end up contracting their abdominal, gluteal, and hip adductor muscles, and try to exaggerate inspiration which will often worsen their condition. Moreover, most of the VVF centres do not have physiotherapists or trained continent nurses to guide the women in performing the correct PFMT . Even if there are professionals, teaching and monitoring the PFMT of patients individually may not be possible due to the high number of victims. Therefore, there is the need to find a conservative approach that can be performed with more ease and possibly in a group to accommodate the large number of the affected women and to encourage peer support, to help the affected women to get back to their normal life and minimize the need for another surgery.
The Paula exercise method also called circular/ring muscle exercise is a growing conservative method used in the treatment of urinary incontinence (UI) in general. It is an easy-to-perform approach, and has been tested to be effective in the management of UI and its associated complications in women without previous fistula repair [27, 29,30,31]. Practically, the Paula exercise method focuses on contracting and relaxing specific circular (or ring) muscles of the body in an effort to rehabilitate other damaged muscles of the body, because the body sphincters works together and their activity can affect one another due to oscillations in the spinal cord [27, 28, 31, 32].
The Paula method is considered an alternative to PFMT and has been found to exhibit comparable efficacy for urinary incontinence [31, 33], including demonstrable long-term effects . A study demonstrated comparable effectiveness of PFMT and PEM on sexual function and quality of life in women suffering from stress urinary incontinence . However, a systematic review reported limited evidence for alternative exercise regimens for the reduction of urinary leakage in women with stress urinary incontinence . The review found methodological limitations in PEM as an alternative to PFMT. The limitations included the fact that one of the studies was a pilot study  with small sample size while the other subjected the control, i.e. the PFMT group, to below-optimal training, and the high loss to follow-up (up to 28%). Additionally, both studies were conducted by the same group of researchers. These factors obviously suggest the need for more studies with robust methodological approaches in diverse groups of researchers from distinct settings to investigate the efficacy of the Paula exercise method. This study aims to contribute to filling this gap and is therefore, targeted at investigating the effectiveness of the Paula exercise method in women with PFRI.