RAMB - AGOSTO 2017

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2017; 63(8):664-680

B) or moderate, weak or very weak. The strongest evidence

will be considered.

We defined seven main questions regarding male uri-

nary incontinence and artificial urinary sphincter as follows:

1. AMS 800 Model.

2. Preoperative period.

3. Perineal versus scrotal approach.

4. Transcorporal approach.

5. Perioperative and postoperative care.

6. Evaluation and conduction of therapeutic failure af-

ter AUS implantation.

7. Complications.

1. AMS 800 M

odel

The objective of our evaluation is to assess the best prac-

tices in the choice and preparation of the AMS 800 urinary

sphincter components, considering primary studies.

Clinical question

What conduct should be adopted in the choice and prep-

aration of the components of the artificial urinary sphinc-

ter model AMS 800? This question was answered in this

evaluation using the PICO method, where P stands for

patients with urinary incontinence due to sphincter de-

ficiency, I refers to intervention with implantation of the

AUS model AMS 800, C is the comparison with implanta-

tion of different components and the preparation of such

(cuff and balloon), and O is the outcome of incontinence

control and complications. Based on the structured ques-

tion, we identified the keywords used as the basis for

searching for evidence in the databases and after the eli-

gibility criteria (inclusion and exclusion), which were

selected to answer the clinical question (Annex I).

Results

In all, 1,757 studies were retrieved. Of these, 20 were se-

lected by title and eight by summary, with reading of the

full text in the second case. After the analysis of the full

texts, 14 studies were included in our evaluation.

25-38

The

main reasons for exclusion were: studies aiming only to

describe the surgical technique, a series of cases with a small

number of patients included (n < 10), and a narrative review.

The surgeon determines the appropriate cuff size to

be used by measuring the circumference of the tissue around

the urethra or the bladder neck. A belt is used for cuff

measurement, available in the device implantation kit,

which should surround the entire urethra circumferen-

tially for proper assessment of its caliber. Additional clear-

ance is required to accommodate the patient’s urethral

tissue between the transurethral device and the cuff. The

thickness of the urethral tissue is patient-specific and re-

quires a surgeon’s assessment to determine its impact on

sizing. In transcorporal implantation (TC) one must not

undersize the cuff size, considering a size 1∕2 cm greater

than the measured value. This is particularly true for old-

er men, since the postoperative urinary retention rate is

significantly higher in these patients (32% [TC] vs. 8% in

peri-urethral implantation, NNH = 4, 95CI 2-28).

(B)

A before-and-after study showed that the percentage

of patients using two or more pads/day was lower in the

larger cuff size group (5.0 to 7.0 cm) compared to patients

with a cuff size of less than 5 cm, at a median follow-up of

6.8 years (9.1 vs. 20.5%, NNT = NS). In addition, cuff size

did not significantly affect the risk of complications.

(B)

In a historical cohort (N = 45 men), one group evalu-

ated implantation of the 3.5 cm cuff in primary and revi-

sion surgery, after repeatedly observing that loose cuffs

led to more severe postoperative incontinence. In this

study, compared to a larger one the 3.5 cm cuff showed

no difference in explantation rate (9% in both groups;

NNT = NS), due to infection and/or erosion, in an average

follow-up of 12 months.

(B)

Another historical cohort (N = 59 men) evaluated the

association of the difference between the urethral circumfer-

ence and the cuff size chosen (ΔC), in its effect on postop-

erative incontinence in a median follow-up of 4.2 years. The

median size of the urethral cuff was 3.8 cm and 66% of the

patients had a 4.0 cm cuff implanted. In a long-term follow-

-up, when ΔCwas < 4mm, a higher rate of urinary retention,

erosion and atrophy was observed, and when ΔC was ≥ 4

mm, better continence and satisfaction were observed

(p<0.05). The results of this study suggest that a moderate

increase in cuff size can produce better results in the long

run. Furthermore, it demonstrated improvement in conti-

nence rates when surgeons opted for a larger cuff size when

the urethral circumference was between two cuff sizes.

(B)

A historical cohort (N = 176 men) evaluated results

comparing 100 cuff measuring 3.5 cm with 76 cuffs of

larger sizes. Although there was no difference between

the two groups regarding continence rates (83 vs. 80%,

NNT = NS), patients with a history of irradiation who

underwent 3.5 cm cuff implantation (N = 100) presented

a 17% increase in the risk of erosion through the cuff

(NNH = 6; 95CI 3-22).

(B)

The pressure-regulating balloon (PRB) determines

the amount of pressure applied by the cuff. The surgeon

usually implants the PRB in the pre-vesical space. A more

recent PRB placement technique (pressure of 61-70 cm

of H

O and filled with 24 cc saline) is high submuscular

placement below the rectus abdominis muscle using a