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BACKGROUND:
There has been an effort to reduce the morbidity of continent reconstruction in patients with neurogenic bladder by utilizing augmentation cystoplasty less frequently. Recent research suggests that a significant number of patients who forego augmentation at the time of their initial surgery will require augmentation at a later date, however, our ability to predict patients need for augmentation is still limited. In our practice we have selectively chosen patients with favorable preoperative urodynamics as candidates for avoidance of augmentation at the time of reconstruction. We aim to describe our experience with bladder neck reconstruction (BNR) without augmentation to assess the need for later surgeries including augmentation and significant differences in preoperative characteristics that might predict need for secondary procedures.
METHODS:
Medical records were reviewed for all neurogenic bladder patients undergoing continent reconstruction. Inclusion criteria included spinal dysraphism as primary diagnosis and avoidance of augmentation at time of initial reconstruction. Patient information was collected including age at surgery, preoperative BMI and age adjusted z-score, EGFR, presence of hydronephrosis or reflux, and preoperative urodynamic study data. Matching postoperative data as well as information on secondary procedures including augmentation was collected. Wilcoxon rank-sum test and student t-test were performed to identify statistically significant differences between patient populations.
RESULTS:
A total of 30 out of 106 continent reconstruction patients met inclusion criteria. Demographic data is presented in table 1.

Table 1: Patient demographic data

Male : Female	1 : 1.14
Diagnosis	Spina bifida (66.7%) Lipomeningocele (16.7%) Caudal regression (6.7%) Sacral agenesis (6.7%) VACTERL (3.3%)
VP shunt	16 (53.3%)
Prior surgeries	Vesicostomy: 2 (6.7%) Reimplant: 1 (3.3%) Cystolythalopaxy: 1 (3.3%)
Mean age at surgery (years)	10.8 (3.8-17.8)
Mean follow-up after surgery (months)	63.9 (0.66-161.2)
Preoperative hydronephrosis	2 (6.7%, both mild)
Preoperative VUR	4 patients (13.3%) Grade 2: 1 (3.3%) Grade 3: 2 (6.7%) Grade 5: 1 (3.3%)

Twelve patients (40%) underwent bladder neck injection after initial surgery. No preoperative factors were predictive of need for bladder neck injection. In total 11 patients underwent secondary reconstruction procedures (augmentation, bladder neck closure, etc.), including 8 who had an initial attempt at bladder neck injection. Patients requiring secondary reconstruction were more likely to already have undergone bladder neck injection than those not requiring other secondary reconstruction (72.7% vs 21.1%, p = 0.009). A total of 8 patients (26.7%) underwent eventual augmentation. There were no statistically significant differences in preoperative characteristics of patients requiring eventual augmentation. Comparison of preoperative and postoperative urodynamics (table 2) revealed a significant decrease in percent of expected bladder capacity after BNR.

Table 2: Urodynamics before and after bladder neck reconstruction

	Before	After
Anticholinergics	15 (50%)	29 (96.7%)
Mean % of predicted capacity	92.8% (38-175)	70.4% (30-122.3, p=0.013)
Compliance (ml/cm H20)	14.8 (2.5-33.3)	14.3 (1.35-79.5)
Detrusor end filling pressure (cm H2O)	31.4 (5-105)	34.5 (1-80)

CONCLUSIONS:
Even in selected favorable patients, a significant number of those undergoing BNR without augmentation will progress to need augmentation in the future. Nearly 75% of patients will require subsequent procedures after bladder neck injection. Need for future augmentation after BNR remains difficult to predict. Bladder neck procedures have the potential to significantly decrease bladder capacity despite anticholinergics and careful follow-up is needed postoperatively.