Aims of study
Lower urinary tract symptoms due to benign enlargement of the prostate is one of the most prevalent disease in men. Patients presenting with acute urinary retention secondary to BEP have a straight forward post operative outcome following TURP.
The post operative outcomes are less predictable in patients with chronic urinary retention(widely accepted as a residual volume >300ml).prior studies have suggested the use of urodynamics preoperatively to categorise chronic retention in to low pressure and high pressure retention and to proceed cautiously with bladder outlet procedure in low pressure retention. Our objective was to assess the significance of a preoperative Urodynamics for prognosticating patinets undergoing TURP for chronic retention.

Hypothesis
Preoperative urodynamics is not relevant in the prognostication of patients undergoing bladder outlet procedures in patients with chronic urinary retention.

This is a single centre prospective observational cohort study. The study population included 50 consecutive male patients, with BPH with BOO undergoing TURP. Clearance was obtained from the Institutional Ethics committee for performing the study.
Standard routine care practices were followed including Patient proforma, IPSS QoL score, Uroflowmetry/PVR, USG KUB and  UDS for all patients with chronic retention. After routine workup patients were subjected to TURP and post operative outcomes (IPSS QoL, Uroflowmetry/PVR, CIC requirement) was followed up at 3 months. Comparison between pre operative and post operative IPSS and Uroflowmetry findings in patients with chronic retention between high pressure and low pressure UDS tracings were done to assess if there is any significant improvement in IPSS- QoL, flow rates and post void residual volumes..

In our study, The mean age of sample population is 70.28 ± 7.43. Of the 50 consecutive male patients attending our OPD who were included in the study, 21 of them had urodynamically low pressure retention while 29 of them had high pressure retention
. 
          The pre operative flow parameters were measured and the median PVR in the low pressure group was 415 ml and high pressure group was 390ml. The preoperative median Qmax was 6.50 in the high pressure group and median Qmax in the low pressure group was 4.20, the difference between 2 groups were statistically significant (p=0.045).  
 

The preoperative IPSS median score  for the whole cohort was 24(IQR 21-27) and QoL was 5(IQR 4-6) .. The improvements in post operative IPSS and QoL scores were statistically significant (p<0.001) for the complete cohort with median IPSS score of 8.5(IQR 6-10.25) and QoL 2(1-2.2).  
The results were similar on analyzing pre and post operative IPSS and QoL within the low pressure and high pressure chronic retention subgroups. 
Median post operative IPSS was lower in the high pressure chronic retention group , 7.5(IQR6-10) compared to 9.5(IQR 6.5-12) , the difference was in favour of the high pressure group but was not statistically significant. There was also no statistical difference between QoL scores of the two groups.  

The post operative median PVR of high pressure group was 45 (20-100) and low pressure group was 80 (40-120) which were  a statistically significant improvement compared to pre operative values.

Our study did not demonstrate a significant predictive capability for preoperative urodynamics to post operative surgical outcomes.

The role of Urodynamics studies prior to TURP in patients with chronic urinary retention is not pivotal in prognosticating patients with chronic urinary retention. This may help to reduce healthcare costs and the burden of unnecessary testing on patients