AUA 2019: Contemporary Evaluation & Treatment of Primary Bladder Neck/Outlet Obstruction in Women
Diagnosis: Dr. Doreen E. Chung
Dr. Chung elaborated further on the specific methods for diagnosing bladder outlet obstruction. She presented the International Continence Society (ICS) definition of bladder outlet obstruction: It is a reduced urine flow rate and/or pressure of a raised PVR and increased detrusor pressure. Going further, it is usually diagnosed by studying the synchronous values of urine flow rate and detrusor pressure and any PVR measurements.
She explained that there are no widely accepted urodynamic parameters, though usually, nomograms use PdetQmax >20-25cm H20 and Qmax <11-15ml/s. Non-invasive uroflow can also be of diagnostic utility, however a strong emphasis in Dr. Chung’s presentation, and throughout this session, was how useful fluoroscopy during UDS is for confirming the diagnosis of BOO and the specific cause. The diagnostic steps that she presented as previously published were to establish one or more of the following criteria: Free Qmax <12ml/s combined with sustained detrusor contraction and PdetQmax>20cm H20 on pressure flow studies; Obvious radiographic evidence of BOO with sustained detrusor contraction >20cm H20 and poor Qmax regardless of free Qmax; Inability to void with transurethral catheter in place despite sustained Pdet of at least 20cm H20. (Blavias & Groutz, Neurourol Urodyn, 2000). The three types of BOO she explained are: anatomical, neurologic, and functional, which includes PBNO.
In regards to PBNO workup, Dr. Chung emphasized the following: Detailed H&P, non-invasive uroflow, PVR, cystoscopy, video urodynamics (VUDS), and transvaginal ultrasound. She explained PBNO patients will typically present with both storage and voiding symptoms, and some patients may even present with urinary retention or even renal failure. The challenge still remains in terms of differentiating between dysfunctional voiding and PBNO. She directed our attention to a retrospective study of VUDS of patients with PBNO and dysfunctional voiding. Women with dysfunctional voiding had more storage symptoms and fewer voiding symptoms. Patients with voiding dysfunction had higher Qmax (12 vs. 7 ml/s, p-0.027) and lower PVR (125 vs. 400ml, p-0.012). (Brucker et al, J Urol 2012). She concluded with VUDS demonstrating the fluoroscopic differences, mainly the open vs. closed bladder neck, observed in dysfunctional voiding and PBNO respectively.
Non-surgical treatments: Dr. Lara MacLachlan
Dr. MacLachlan gave an overview of non-surgical treatments for PBNO and divided them into three categories: Observation and surveillance, intermittent catheterization, and medical management (alpha-blockers).
She recommended observation of patients with symptoms that are not very bothersome in the absence of concerning findings on evaluation. She still would recommend some form of surveillance, in the form of repeat office visits, with non-invasive uroflow and PVR.
In regards to clean intermittent catheterization, she explained this should be used cautiously and only when necessary. Although it does facilitate bladder emptying, and thus may improve lower urinary tract symptoms (LUTS), it comes at the risk of asymptomatic bacteriuria and possible urinary tract infection. She also instructed that it is contraindicated in patients with decreased bladder compliance and should be avoided in these patients.
She continued on to review the potential benefit of alpha-blocker medications in a female with PBNO since alpha-1 adrenergic receptors are also found in the bladder neck smooth muscle. Although few studies have been done with alpha blockers in this scenario, she reviewed them in her discussion.
In one study that included 24 patients with PBNO, 12 (50%) responded to alpha-blocker therapy with terazosin. They demonstrated an improvement of maximum flow rates from 9.55 to 15.06 ml/s, and PVR from 277 to 28ml. (Kumar et al. J Urol 1999). In another using tamsulosin in 18 patients, 10 (56%) responded, with improved max flow rates from 11.2 to 18.3ml/s, PVR from 133.5 to 40.3ml, and decreased pdet max during voiding from 64.3 to 44.8 cmH20. (Psichedda et al. Urol Int 2005).
She concluded with a discussion of future directions, utilizing onobotulinumtoxinA injections to the bladder neck, which has previously been described in men. In one study, using 100 units in 2ml injected at 4 quadrants at bladder neck showed improvement in IPSS from 21.4 to 9.4, and PVR from 263.3 to 91.6ml. (Pradhan, Indian J Urol 2009).
Surgical Treatments: Dr. Priya Padmanabhan
Dr. Padmanabhan discussed the different techniques and literature describing transurethral incision of the bladder neck (TUIBN) for PNBO. She explained that this procedure was first described by Turner-Warwick in 1973, and was done at the 12 o’clock position to avoid fistulation. Since then follow up studies have described alternative techniques employing multiple sites: 5 and 7 o’clock; 5, 7, and 12 o’clock; or 4 sites – 3, 6, 9, 12 o’clock. Concerns with a single incision were that it could not adequately disrupt a solid ring of tissue to treat the condition.
The study she reviewed with three incision sites (5, 7, and 12 o’clock) reported a 71% success rate, with a 14% rate of repeat resection and 4/92 patient developed temporary SUI. (Jones et al 1979).
A study she reviewed with four sites (3, 6, 9, 12 o’clock) reported in 30 patients a 100% success rate in terms of subjective improvement and objective improvement (PVR, flow rate, and pdet) at 5 years. (Jin et al 2012).
Another study she discussed with different position incisions (n=63 at 5 and 7 o’clock; n=21 at 2 and 10 o’clock) reported a 77.4% success rate, with a 7.1% repeat resection rate. In this study the also reported a 3/63 rate of fistula in the 5 and 7 o’clock group. (Zhang et al 2014).
And the most recent study reviewed used a 2-stage TUIBN using a resection loop at 5 and 7 o’clock, and a need electrode at 12 o’clock. They reported 100% success at 1 year and no complications. (Shen et al 2016).
Following these presentations, two case studies were reviewed. First was an 80 year old female with a history of spine surgery, Lyme disease, and history of urethral dilutions with urinary retention, elevated PVR 700ml; with a UDS showing possible decreased contractility who was started on CIC.
She underwent repeat testing VUDS, uroflow, renal US, voiding diary, and cystoscopy. Her repeat UDS showed normal compliance and had detrusor contraction, but no funneling noted on VCUG, and so underwent TUIBN. This was a demonstration that the previous history could confuse the diagnosis, and prevent a possible diagnosis of PBNO, which was best appreciated on fluoroscopy during voiding.
An additional case was presented with a 40 year old female with incomplete emptying and valsava voiding. She had failed tamsulosin and a previous UDS showed a normal compliance bladder with a high pressure detrusor contraction. A then repeated with fluorourodynamics showed an open bladder neck less consistent with a PBNO. This was an example of how an initial UDS tracing might be highly suspicious for PBNO, but the value of repeating it with concomitant imaging was of significant utility.
Presented by:
Benjamin Brucker, MD Director of the Division of Female Pelvic Medicine and Reconstructive Surgery and Neuro-Urology, director of FRMRS fellowship program, Associate Program Director of the Urology Residency for the Department of Urology and Obstetrics and gynecology at NYU Langone Health,
Doreen E. Chung, MD, FRCSC, Columbia University; Lara MacLachlan MD, Beth Israel Lahey Health; Priya Padmanabhan, MD, FACS, University of Kansas
Lara MacLachlan, Lahey Hospital & Medical Center
Priya Padmanabhan, MD MPH, Urology, Female Pelvic Medicine and Reconstructive Surgery, University of Kansas Physicians, Kansas City, KS
Written by: Ross Moskowitz, MD; Assistant Clinical Professor of Urology, University of California Irvine Medical Center; @rossmosk1 at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois