Injection Techniques for Bladder and Sphincter

and Joseph M. Gleason2



(1)
Pediatric urology, Division of Urology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada

(2)
Division of Paediatric Urology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada

 



Abstract

The past decade has witnessed a surge in the use of endoscopic-guided injection of different substances to treat pediatric urological issues, most notable vesicoureteral reflux and urinary incontinence. Two compounds – onabotulinum toxin A and dextranomer/hyaluronic acid – stand out as the most commonly employed ones administered in this “minimally invasive” fashion, often avoiding or delaying further surgical interventions in many patients. Although seemingly simple procedures, attention to indications, contraindications, technique, and monitoring is crucial in order to maximize benefits while avoiding misuse and/or harm. In this chapter we will focus on administration technique in the context of the most common indications, addressing potential pitfalls and complications.


The online version of this chapter (doi:10.​1007/​978-1-4471-5394-8_​24) contains supplementary material, which is available to authorized users.


Keywords
Endoscopic injectionBulking agentDextranomer/hyaluronic acidBotulinum toxinUrinary incontinenceVesicoureteral reflux



Why Endourological Techniques for Management of Pathologic Conditions of the Lower Urinary Tract in Children?


Urology has traditionally been an endoscopic specialty, being at the forefront of minimally invasive and diagnostic interventions based on this technology. With scientific advances and miniaturization of equipment, access devices initially designed for adults have been easier to transfer to the pediatric population. Indeed, it is this process that has allowed for easier (nontraumatic) entry through the meatus and urethra, avoiding subsequent problems, most notably iatrogenic trauma and stricture formation. The ultimate testament to this miniaturization process has been the commonplace use of transurethral resection of posterior urethral valves or incision of obstructing ureteroceles in neonates, considered by many the standard of care for the initial management of these conditions with the use of infant resectoscopes.

In many ways, endoscopic techniques represent one of the most common forms of “natural opening” surgery, gaining access to the lower urinary tract via the urethral meatus. Far from being solely employed as a diagnostic intervention (as often seen in older patients), access allows delivery of different substances directly into the bladder neck, trigone, or detrusor muscle, aided by a needle with standardized depth mark(s). As such, endourological access is a means of delivery, rather than a surgical technique per se; the challenge centers on performing the actual administration and the rationale for selecting such intervention over other options. These procedures are commonly shorter in duration and associated with quicker recovery, with the obvious advantage of not generating visible scars. Nevertheless, although appealing in its simplicity and lack of invasiveness, contrast with traditional (open) techniques often demonstrates lower efficacy and – due to their novelty – shorter follow-up.


The STING Revolution


With little doubt, pediatric urology grew as a subspecialty with the acceptance of vesicoureteral reflux as an important clinical entity, amenable to surgical correction in order to limit short- and long-term morbidity [1]. This popularization generated a “need” for surgical treatment, questioned by many due to the morbidity of the procedure, particularly for low grades of reflux in otherwise healthy children, thus fueling the role of nonsurgical and less-invasive surgical options. The widespread use of endoscopic injection has its origins on the landmark work by Puri and O’Donnell who pioneered the use of Teflon® as a bulking agent to manage this condition in a minimally invasive fashion [2]. The technique (so-called classic STING) involved a single submucosal injection at the 6 o’clock position of the ureteral meatus. Although initially met with skepticism and some resistance, a few decades later this delivery modality (with some modifications) has surpassed in popularity other surgical options in many parts of the world. Even though the employed bulking substance has changed, currently heavily favoring dextranomer/hyaluronic acid, the administration principles remain fundamentally unchanged. In addition, the attractiveness of lower surgical morbidity by taking advantage of natural entry points fueled enthusiasm for expanding the application to other conditions. It is probably fair to say that the contemporary success and enthusiasm for endoscopic injection largely rest on this pioneer work.


Basic Principles of Surgical Technique


The “art” of endoscopic treatment heavily weighs on the injection technique rather than access. Cystoscopy is a basic urological skill, and getting to the injection site adds little in terms of additional challenge, except for minor adjustments that are required when employing a straight working channel (angled or offset ocular) scope, as well as negotiating the urethra, of limited caliber and potentially more delicate than in adults. On occasion, entry options may be limited or favored to a catheterizable channel (i.e., Mitrofanoff or Monti-Yang), which needs to be negotiated as gently as possible, and drug delivery adjusted based on the limitations imposed by the different “view” obtained.

The injection technique itself has to be adapted to the indication for surgery and the substance to be delivered. For vesicoureteral reflux, most commonly treated by injection of dextranomer/hyaluronic acid, the compound is precisely placed in a submucosal plane – through one or two injection sites – at the level of the ureteral orifice and intramural ureter. Similarly, in selected cases, this substance can be delivered at the bladder neck/proximal urethra level to create resistance (or “controlled obstruction”), in an attempt to address stress urinary incontinence. In contrast, botulinum toxin is injected at multiple sites in order to cover the muscle mass targeted for temporary paralysis. The latter case is seemingly less impacted by a steep learning curve, yet requires skill avoiding limited visualization as the case progresses due to early injury of large submucosal vessels, as well as good spatial planning in order to evenly distribute the fixed predetermined dose of diluted botulinum toxin throughout the treatment area.

In the following paragraphs, we will address specific issues based on injection sites and pathology, attempting to create a clear distinction between the detrusor muscle, ureterovesical junction, and bladder neck/sphincter. In addition, the authors’ preference for endoscopic management is summarized in Tables 24.1, 24.2, and 24.3.


Table 24.1
Subureteric endoscopic injection with bulking agent for treatment of vesicoureteral reflux































































Indications

Primary vesicoureteral reflux

Reflux after previous ureteral reimplantation

Contraindications (relative)

Reflux recurrence after previous endoscopic injections (≥2)

Secondary vesicoureteral reflux (neuropathic bladder, posterior urethral valves)

Refluxing obstructed megaureter

Nonfunctioning (refluxing) renal unit

Ectopic ureter (bladder neck)

Active urinary tract infection

Equipment

Straight channel (angled ocular) pediatric rigid cystoscope

Deflux® needle (3.7Fr x 23G × 350 mm) with circular mark 6 mm from the tip

Deflux® gel prefilled syringe (dextranomer microspheres [50 mg/mL] in hyaluronic acid; microsphere range, 80–250 μm with an average size of about 130 μm)

Technical preferences

Perform cystoscopy in “low” lithotomy position, avoiding too much flexion at the hips

Prophylactic IV antibiotics after induction

Urine culture (optional)

Double HIT injection: first, bolus in the intramural aspect of ureter; second, one at 6 o’clock position of the meatus (“classic STING”)

Injection done at ~50 % of bladder fill, avoid over-distention

Injection should be done slowly, avoid “pushing” the needle into the tissue, rather relax the scope and needle allowing the agent to favor the submucosal plane

Consider a gentle rectal exam, particularly if there is history of constipation and/or anterior displacement of bladder by distended rectum during cystoscopy

Postoperative management

Procedure done as day surgery, discharge once recovered from anesthetic

Continue antibiotic prophylaxis until first follow-up visit

Avoid constipation (liberal use of PEG or other stool softener)

Reinforce good bladder/voiding habits

Follow-up ultrasound at 6–8 weeks, sooner if complaining of back pain or presents with clinical evidence of pyelonephritis

Postoperative cystogram OPTIONAL, based on parental preference. Support selective cystogram only in cases with recurrent febrile urinary tract infections



Table 24.2
Bladder neck injection with bulking agent for urinary incontinence





























































Indications

Mild to moderate urinary incontinence due to bladder outlet deficiency

Contraindications (relative)

Lack of improvement after previous bladder neck injections (≥2)

Low compliance/high filling pressure, bladder not responsive to medical therapy

Previous bladder neck procedures (except bladder wall flap-based ones)

Previous lower abdominal procedures that would raise concern for bowel adhesions in suprapubic region (for antegrade technique)

Equipment

Straight channel (angled ocular) pediatric rigid cystoscope

Deflux® needle (3.7Fr x 23G x 350 mm) with circular mark 6 mm from the tip

Deflux® gel prefilled syringe (dextranomer microspheres [50 mg/mL] in hyaluronic acid; microsphere range, 80–250 μm with an average size of about 130 μm)

Large-bore AngioCath, peel-away sheath, and guidewire

5 mm laparoscopic port

Technical preferences (antegrade approach)

Prep genital and lower abdominal region

Prophylactic IV antibiotics after induction

Urine culture

Perform cystoscopy through urethra and over-distend the bladder

Under cystoscopic visualization, advance AngioCath through the abdominal wall, aiming for entry towards the dome of the bladder

Advance guidewire through AngioCath and dilate tract with peel-away sheath, then advance sheath of Step® trocar into bladder over wire, and radially dilate with 5 mm trocar

With CO2 gas insufflation, perform antegrade submucosal injection of bulking agent at the bladder neck, either two or four quadrants depending on amount of coaptation obtained (1 cc of Deflux® per quadrant)

Place suprapubic catheter

*If patient has a Mitrofanoff or Monti channel, the procedure can be done through it as long as adequate access to bladder neck can be achieved

*Antegrade access may not be a good option in patients with previous augmentation cystoplasty

Postoperative management

Procedure done as day surgery, discharge once recovered from anesthetic

Keep suprapubic catheter to straight drainage for a week or two

If patient is not on clean intermittent catheterization before surgery, use suprapubic tube to measure postvoid residuals



Table 24.3
Bladder wall botulinum toxin injection for neuropathic dysfunction



























Indications

Urinary incontinence due to neuropathic detrusor overactivity

Maximum dose of anticholinergics given without improvement or anticholinergic intolerance

Low capacity, low-compliance bladder with incontinence and/or upper tract deterioration, as an alternative before considering reconstruction (i.e., augmentation cystoplasty)

Contraindications (relative)

Lack of improvement after previous botulinum toxin injection

Evidence of incompetent bladder neck (outlet)

History of adverse reaction to botulinum toxin injection

Equipment

Straight channel (angled ocular) pediatric rigid cystoscope

Deflux® needle (3.7Fr x 23G × 350 mm) with circular mark 6 mm from the tip

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Dec 28, 2016 | Posted by in PEDIATRICS | Comments Off on Injection Techniques for Bladder and Sphincter
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