Synostosis Between Pubic Bones due to Neurogenic, Heterotopic Ossification

Abstract

Neurogenic, heterotopic ossification is characterised by the formation of new, extraosseous (ectopic) bone in soft tissue in patients with neurological disorders. A 33-year-old female, who was born with spina bifida, paraplegia, and diastasis of symphysis pubis, had indwelling urethral catheter drainage and was using oxybutynin bladder instillations. She was prescribed diuretic for swelling of feet, which aggravated bypassing of catheter. Hence, suprapubic cystostomy was performed. Despite anticholinergic therapy, there was chronic urine leak around the suprapubic catheter and per urethra. Therefore, the urethra was mobilised and closed. After closure of the urethra, there was no urine leak from the urethra, but urine leak persisted around the suprapubic catheter. Cystogram confirmed the presence of a Foley balloon inside the bladder; there was no urinary fistula. The Foley balloon ruptured frequently, leading to extrusion of the Foley catheter. X-ray of abdomen showed heterotopic bone formation bridging the gap across diastasis of symphysis pubis. CT of pelvis revealed heterotopic bone lying in close proximity to the balloon of the Foley catheter; the sharp edge of heterotopic bone probably acted like a saw and led to frequent rupture of the balloon of the Foley catheter. Unique features of this case are: (1) temporal relationship of heterotopic bone formation to suprapubic cystostomy and chronic urine leak; (2) occurrence of heterotopic ossification in pubic region; (3) complications of heterotopic bone formation viz. frequent rupture of the balloon of the Foley catheter by the irregular margin of heterotopic bone and difficulty in insertion of suprapubic catheter because the heterotopic bone encroached on the suprapubic track; (4) synostosis between pubic bones as a result of heterotopic ossification..Common aetiological factors for neurogenic, heterotopic ossification, such as forceful manipulation, trauma, or spasticity, were absent in this patient. Since heterotopic bone formation was observed in the pubic region after suprapubic cystostomy and chronic urine leak, it is possible that risk factors related to the urinary tract might have played a role in heterotopic bone formation, which resulted in synostosis between pubic bones.

Persistent urine leakage around a suprapubic catheter: the experience of a person with chronic tetraplegia

“…Factors to consider when a spinal cord injury patient with a suprapubic catheter develops persistent leakage of urine around suprapubic catheter are listed in Table 1 . Prolonged urine leakage around a suprapubic catheter can result in complications such as soft tissue infection in the pubic region, bone infection in the pelvis, heterotopic ossification between the pubic bones, maceration and ulceration of skin in groin, perineum and ischial region [ 3 , 4 ]. We describe a cervical spinal cord injury patient’s experience of persistent urine leakage which occurred about three years after undergoing suprapubic cystostomy.…”

Preventable long-term complications of suprapubic cystostomy after spinal cord injury: Root cause analysis in a representative case report

“…A few rare and unusual complications of suprapubic cystostomy have been documented. Heterotopic bone formation was observed in the pubic region after suprapubic cystostomy and chronic urine leak [ 6 ]. Hourglass deformity of urinary bladder is another very unusual late complication of suprapubic cystostomy in persons with neuropathic bladder.…”