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IS INCREASING BLADDER OUTLET RESISTANCE WITHOUT AUGMENTATION SAFE IN NEUROGENIC BLADDER?
John Weaver, M.D.¹, Xander Knight, M.D.², Joel Koenig, M.D.³, Joel Vetter, M.S.¹, Douglas Coplen, M.D.¹, Paul Austin, M.D.⁴.
¹Washington University School of Medicine, Saint Louis, MO, USA, ²Oregon Health Science University, Portland, OR, USA, ³Mercy Childrens Hospital, Kansas City, MO, USA, ⁴Texas Children's Hospital, Houston, TX, USA.

Background:We hypothesized that, selectively choosing only patients with favorable preoperative characteristics for BNPs without AC, a significant number of children undergoing BNPs without AC would not develop changing bladder dynamics that lead to recurrent incontinence and risk for upper tract changes.
Methods:We retrospectively queried our institution’s EMR for all neurogenic bladder patients with spinal dysraphism as their primary diagnosis who underwent BNPs at our institution between 2000 and 2017.
We separated these patients into two groups. One group who did not undergo AC at the time of their initial BNP procedure (Group 1) and a second group of patients who had concomitant AC (Group 2).
Results:Group 1 included 30 patients. Demographic data for Group 1 can be found in Table 1. Group 2 included 63 patients.
Preoperative urodynamic data comparing the two groups is available in Table 2. Compared to Group 1, Group 2 had a higher proportion of patients with HDN (22.2% vs 3%) and VUR (38.1% vs 13.3%) preoperatively.
A summary of the postoperative outcomes for all 30 patients in Group 1 can be found in Table 3. No patient in this group was preoperatively or postoperatively diagnosed with any stage of CKD. Eighteen of the 30 patients were on anticholinergics prior to their initial surgery and 28 of the patients were on anticholinergics at some point following their initial BNP.
For Group 1, a list of preoperative to postoperative urodynamics changes can be found in Table 4. There was also a significant difference when comparing changes from preoperative to postoperative urodynamics in patients requiring augmentation to those who did not. See Table 5.
We were unable to identify any preoperative risk factors that predicted the need for AC, BNP or BNI. Additionally, when we separated patients based on their indication for augmentation, we were still unable to identify any preoperative risk factors that predicted the need for augmentation. We found that the type of bladder neck procedure that was performed did not predict any postoperative outcomes.
Conclusions:Our data illustrates BNR without AC is safe in selected patients with normal bladder compliance and normal/near normal expected capacity. None of our patients suffered any significant degree of renal injury and 47% of our patients did not require any major reconstructive procedure with six-year follow-up.

Table 1. Demographics of Group 1.

Male: Female	1 : 1.14
Diagnosis
Myelomeningocele	21 (70.0%)
Lipomeningocele	5 (16.7%)
Caudal Regression	2 (6.7%)
Sacral Agenesis	2 (6.7%)
VP Shunt	16 (55.2%)
Prior Surgeries
Vesicostomy	2 (6.7%)
Ureteral Reimplant	1 (3.3%)
Cystolitholapaxy	1 (3.3%)
Mean Age at Surgery (years)	10.8 (3.8 - 17.8)
Mean Follow-up after surgery (months)	74.5 (0.66 - 168.5)
Preoperative Hydronephrosis	1 (3.3%)
Preoperative VUR
Yes	4 (13.3%)
Grade 2	1 (3.3%)
Grade 3	2 (6.7%)
Grade 5	1 (3.3%

Table 2. Comparison of preoperative urodynamics between Group 1 and Group 2.

	Group 1 (N=30)	Group 2 (N=63)	p-value
Preop Percent predicted bladder capacity
Mean (SD)	89.5(31.6)	46.1(22.1)	<0.001
Min	34.7	10.5
Max	175.9	102.6
Preop Detrusor end filling pressure (mmHg)
Mean (SD)	26.1(17.1)	37.0 (22.1)	0.035
Min	5.0	5.0
Max	69.0	88.0
Preop Detrusor leak point pressure (mmHg)
Mean	28.9	43.5	0.146
St. Dev.	19.8	35.0
Min	5.0	10.0
Max	69.0	170.0
Preop Compliance (ml/cm H2O)
Mean	19.7	6.4	<0.001
St. Dev.	20.0	5.7
Min	2.8	1.0
Max	102.2	24.5

Table 3. Postoperative outcome data. Overactivity = OA, compliance = C, Intraoperative decision = IO

Patient	Initial BNP	Underwent subsequent BNI	Underwent repeat BNP	Underwent AC (Indication)	Developed VUR	Developed HDN
1	Biologic sling			X (OA)
2	Fascial sling	X			Grade 1
3	Fascial sling	X	BNC
4	Fascial sling
5	Fascial sling
6	Fascial sling
7	Fascial sling
8	Fascial sling	X	BNC	X (C)
9	Biologic sling					Mild
10	Fascial sling	X	Fascial sling	X (OA)
11	Fascial sling			X (C)
12	Fascial sling	X		X (OA)
13	Fascial sling			X (C)
14	BNC		BNC
15	Fascial sling
16	Young Dees Leadbetter BNR			X (C)	Grade 3	Moderate
17	Fascial sling
18	Fascial sling
19	Fascial sling	X
20	Biologic sling			X (IO)	Grade 3	Moderate
21	Fascial sling			X (SI)
22	Fascial sling	X	BNC
23	Biologic sling	X	Young Dees Leadbetter BNR
24	Young Dees Leadbetter BNR		BNC	X (C)
25	Biologic sling
26	Biologic sling		AUS
27	Biologic sling		BNC	X (C)
28	Biologic sling			X (IO)
29	Fascial sling
30	Fascial sling	X

Table 4. Comparison of Group 1 preoperative and postoperative urodynamics.

	Preoperative (Mean)	Postoperative (Mean)	Mean of Difference	Paired T-test p-value
Compliance	16.2	12.3	-3.9	0.439
Detrusor Leak Point Pressure	56.5	50.0	-6.5	Insufficient complete pairs
Detrusor End Filling Pressure	29.8	44.7	14.8	0.028
Expected Bladder Capacity (%)	93.4%	67.3%	-26.1%	0.005

Table 5. Comparison of preoperative and postoperative urodynamics in Group 1 patients based on AC st

	Augment = No (18)	Augment = Yes (12)	p-value
Preop Percent predicted bladder capacity			0.325
Mean	92.7	84.6
St. Dev.	39.6	12.6
Preop Detrusor end filling pressure (mmHg)			0.816
Mean	25.1	27.6
St. Dev.	13.6	21.9
Preop Detrusor leak point pressure (mmHg)			0.317
Mean	23.3	35.5
St. Dev.	13.1	25.3
Preop Compliance			0.895
Mean	19.3	20.3
St. Dev.	21.9	17.7
Postop Percent predicted bladder capacity			0.043
Mean	80.8	54.9
St. Dev.	27.5	29.2
Postop Detrusor end filling pressure (mmHg)			0.698
Mean	41.2	47.8
St. Dev.	24.9	24.5
Postop Detrusor leak point pressure (mmHg)			-
Mean	42	46.7
St. Dev.	-	22.3
Postop Compliance			0.062
Mean	18.1	6.9
St. Dev.	22.7	8.2
Change in predicted bladder capacity			0.605
Mean	-22.8	-29.1
St. Dev.	46.1	29.4
Change in Detrusor end filling pressure (mmHg)			0.460
Mean	10.2	19.1
St. Dev.	30.6	27.8
Change in Detrusor leak point pressure (mmHg)			-
Mean	-8.0	-5.0
St. Dev.	-	-
Change in Compliance			0.036
Mean	5.9	-12.8
St. Dev.	22.2	19.8

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