Introduction and Objective: Conditional electrical stimulation for neurogenic detrusor overactivity has been studied using involuntary detrusor pressure rises as a trigger to start stimulation. Detrusor pressure rises were detected by transurethral and transanal catheters for bladder and abdominal pressure registration. The use of these catheters is not suitable in daily life. Some spinal cord injury patients with neurogenic bladder overactivity can sense bladder fullness or involuntary detrusor pressure rises by normal bladder sensations or non-specific bladder sensations, like abdominal fullness or vegetative symptoms. We studied the usefulness of bladder sensations for conditional electrical stimulation in spinal cord injury patients with neurogenic bladder overactivity.
Methods: 11 Spinal cord injury patients who were supposed to have neurogenic bladder overactivity underwent conventional cystometry. Conventional cystometry was performed at a filling rate of 20 ml/min with water at room temperature. The patients also underwent ambulatory urodynamics (six hours) with a portable recording device at the same day immediately after conventional cystometry. Patients were instructed to do normal daily activities and to operate the buttons at the ambulatory device for registration of event markers: “activity”, “(non-specific) bladder sensations”, “micturition/intermittent catheterisation” and “urinary incontinence”. The presence of detrusor pressure rises (DPR) of ≥10 cmH2O were defined as detrusor overactivity. The time duration of a detrusor pressure rise above 40 cmH2O was registered separately.
Results: We included nine male and two female spinal cord injury patients with a mean age of 38 years and a lesion level between cervical 3 and thoracic 10; 5 complete and 6 incomplete lesions. Nine of the 11 patients reported the presence of bladder sensations in daily life, including non-specific sensations. Six patients reported sensations during ambulatory urodynamics. One of these patients sensed 8 of 47 DPR with an event marker registered at a mean of 9.5 seconds after DPR onset. One patient noticed one of 25 DPR 12 seconds after DPR onset. Another patient had one sensation at 33 seconds after DPR onset and two bladder sensations prior to micturition not related to a DPR. Two patients only had bladder sensations prior to micturition not related to a DPR. One patient had continuous bladder sensations and anal discomfort after insertion of the catheters. Incontinence was not registered well enough by event markers, because some patients were unaware of the exact incontinence time point due to the use of a condom catheter.
Conclusion: Sensation of involuntary detrusor pressure rises in spinal cord lesion patients with neurogenic detrusor overactivity is possible. However, the detrusor pressure rise detection ratio by sensations is too small and reaction time too long for application of bladder sensations for activation of electrical stimulation in conditional stimulation. With technical changes the use of sensations may be possible in the future.
KEYWORDS: Neurogenic detrusor overactivity, bladder sensations, ambulatory urodynamics, conditional stimulation