International continence society defines low compliance in women as bladder compliance less than 10 ml/cm H20 in neurogenic patients and less than 30ml/cm H20 in non-neurogenic patients. Normal compliance is defined as > 30ml/cm H20 in neurogenic patients and > 40ml/cm H20 in non-neurogenic patients. The values in men are not defined clearly. The abnormal compliance has been poorly studied in patient presenting with LUTS except in neurogenic patients. The aim of this study is to determine the diagnosis in patients with poor compliance in both neurogenic and non-neurogenic patients and the urodynamic factors associated with low compliance.

Men undergoing urodynamics for evaluation of lower urinary tract symptoms (LUTS) from January 2021 to March 2022 are included in this study. This is an original retrospective cohort study. Preoperative evaluation included history, physical examination including focussed neurological examination, uroflowmetry (UFM), post void residual urine (PVR) and International Prostate Symptom Score (IPSS). The primary objective was to determine the various urodynamic diagnosis of LUTS in patients with abnormal compliance and secondary objective was to study the association of patients with abnormal compliance with preoperative factors. The criteria of compliance less than 10 ml/cm H20 in neurogenic patients and less than 30ml/cm H20 in non-neurogenic patients was used in this study. All urodynamic studies were analysed and reviewed in multidisciplinary team meeting to ensure accuracy of diagnosis. 
Data are expressed as mean +/- standard deviation, and P-values were obtained using a two-tailed unpaired student t-test for pairwise parametric data comparisons. The Fisher Exact test is used to compare categorical data given as a number (Percentage). Statistical significance was defined as a P value of less than 0.05. The statistical analysis tool SPSS (Statistical Package for the Social Sciences) v25 was used.

Study included 110 male patients. The mean duration of symptoms was 24 +/- 25 months. The filling rate in urodynamic study was kept at 10-20ml/min to reduce any artifacts in bladder compliance due to filling of bladder. There were 15 (14%) patients with neurogenic abnormalities. The mean age (SD) of neurogenic patients was 31.3+/-14.4 years and the duration of symptoms was 26.8 +/- 31.1 months. The mean compliance of these patients was 27.6+/-17.3 ml/cm H20. Low compliance was found in three patients with neurogenic abnormalities. All three patients had detrusor underactivity and associated sacral neurological lesions. There were 95 (86%) patients with non- neurogenic abnormalities. The mean age and compliance were 43.8 +/- 18.9 years and 36.7 +/- 30.14 ml/ cm H20. This group was further subdivided into patients having low compliance as defined by less than 30 ml/cm H20. There were 51 (46%) patients with mean compliance 16.4 +/- 7 ml/cm H20 and 45 (40%) patients with normal compliance with a mean of 59.7 +/- 29.8 ml/cm H20. Voided volume (VV) and maximum cystometric capacity (MCC) were significantly different in both these groups. (Table 1) The various diagnosis in patients with low compliance are summarised in Table 2.

The three compliance patterns seen were gradual increase seen in patients with spinal cord injury, terminal increase of compliance seen in patient having previous history of pelvic surgery and abrupt increase and plateau which was associated in patients with detrusor overactivity. (1) The low compliance is due to changes in passive properties of detrusor muscle due to structural changes via fibrosis. Other mechanism is due to increased deposition of elastin and collagen leading to hypertrophy of smooth muscle fibres. Changes in the passive characteristics of the detrusor muscle are thought to be the main cause of inadequate compliance because the time gap between the onset of injury and voiding techniques prior to presentation to our centre were considerably different.

Lower urinary tract symptoms caused by low bladder compliance are challenging to treat, and medical professionals should be knowledgeable about how to evaluate and treat these patients.   Low bladder compliance is frequently overlooked, and physicians should always have a high index of suspicion for this diagnosis symptoms persists after typical therapy. Treatment is frequently challenging and should be personalized for each patient.

Cho S-Y, Yi J-S, Oh S-J. The clinical significance of poor bladder compliance. Neurourol Urodyn. 2009;28(8):1010–4.