Urodynamics in Children

Pediatric Urology

Pelvic Organ Prolapse continued surgical mesh for POP repair was discussed. The Panel consensus2 was that: • The safety of vaginal mesh intended for POP repair is not well established • Depending on the compartment, vaginal placement of mesh for POP repair may not be more effective than traditional native-tissue repair without mesh • The risk/benefit of vaginal placement of mesh for POP repair is not well established Feedback From Outside Urology Urogynecology A well-written commentary by urogynecologists in 2010, prior to the most recent FDA communication, noted that the use of transvaginal mesh in repair of POP and SUI continues to be an excellent option for many patients.3 The article warned that physicians need to be kept up to date on the lack of long-term data surrounding the use of transvaginal mesh in repair of SUI and POP. Mucowski and colleagues3 noted that, in light of the recent US Supreme Court decision in Riegel v Medtronic Inc.,4 and in conjunction with the manufacturer’s use of the learned intermediary doctrine to shift liability to physicians, it is now harder for injured patients to sue manufacturers of medical devices. Patients injured from the use of a medical device may be more likely to sue their physicians and claim lack of proper informed consent. The authors noted that the current legal environment should not deter physicians from offering mesh repair for POP and SUI to those patients who may best benefit. Physicians should properly obtain and document informed consent prior to offering and performing transvaginal mesh repairs.3 Media In 2011, Voreacos and Nussbaum reported that the media has focused on the lawsuits and case studies involved with the pelvic floor mesh.5 The FDA notification brought it to the attention of lawyers who were not aware of this issue previously. None of the cases have gone to trial and women must prove their claims that mesh makers knew that the products were defective and of the safety risks but failed to disclose them. Makers of mesh, including Johnson & Johnson (J&J; New Brunswick, NJ), Boston Scientific (Natick, MA), Bard (Murray Hill, NJ), and American Medical Systems (Minnetonka, MN), told the FDA advisory panel in September 2011 that using mesh in transvaginal procedures is safe and effective and serious injuries are rare. J&J stated that it may be too early to comment on the potential impact of mesh lawsuits, but that the company is willing to conduct studies of the devices to ensure doctors and patients have “informed access to treatment options.”5 Lawyers Lawyers specializing in mesh cases are offering free case reviews since the FDA’s warning. One Web site, ­pelvicmeshlawyers.com, claims that between 2008 and 2010, the number of pelvic mesh complaints tripled over the preceding 3 years, half of which were the result of failed POP repair.6 This Web site offers comprehensive information about vaginal mesh including when it was known that transvaginal implantation of mesh was harmful and where to find details about the FDA transvaginal mesh warning as well as patients’ rights.6 It also notes that these lawyers will work to recover lost wages, pay for medical bills, and compensate for the pain associated with vaginal mesh problems. References 1. 2. 3. 4. 5. 6. US Food and Drug Administration. Urogynecologic surgical mesh: update on the safety and effectiveness of transvaginal placement for pelvic organ prolapse. July 2011. www.fda.gov/downloads/MedicalDevices/Safety/AlertsandNotices/UCM262760.pdf. Accessed February 28, 2012. Obstetrics & Gynecology Devices Panel. Surgical mesh repair of pelvic organ prolapse (POP), September 8-9, 2011. www.fda.gov/downloads/AdvisoryCommittees/ CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/ ObstetricsandGynecologyDevices/UCM271769.pdf. Accessed February 28, 2012. Mucowski SJ, Jurnalov C, Phelps JY. Use of vaginal mesh in the face of recent FDA warnings and litigation. Am J Obstet Gynecol. 2010;203:103.e1-e4. Riegel v Medtronic Inc., 552 US, 312 (2008). Voreacos D, Nussbaum A. The next medical device controversy: vaginal mesh. Business Week. September 15, 2011. www.businessweek.com/magazine/the-next-medical-devicecontroversy-vaginal-mesh-09152011.html. Accessed February 28, 2012. Onder, Shelton, O’Leary & Peterson, LLC/Pelvic Mesh Lawyers. Surgical Mesh Lawyers offer free case review after FDA issues warning regarding serious complications from transvaginal placement of surgical mesh in repair of pelvic organ prolapse. www.pelvicmeshlawyers.com/. Accessed February 28, 2012. Pediatric Urology Urodynamics in Children Ellen Shapiro, MD, FACS, FAAP New York University School of Medicine, New York, NY [Rev Urol. 2012;14(1/2):36-38 doi: 10.3909/riu0549] © 2012 MedReviews®, LLC D rzewiecki and Bauer from Boston Children’s Hospital provide a review of urodynamics (UDS) in children.1 First, a history, physical examination, and a 3-day voiding and bowel diary are obtained. A renal sonogram noting bladder volume, residual volume, and bladder wall thickness is then performed.2 36 • Vol. 14 No. 1/2 • 2012 • Reviews in Urology 40041700002_LiteratureReview.indd 36 20/07/12 2:11 PM Pediatric Urology Most children with nonneurogenic bladder dysfunction are potty trained but subsequently present with lower urinary tract symptoms. Most children with urgency, frequency, and incontinence can be managed with behavioral therapy and anticholinergic medications. UDS is useful when there is no improvement. Kaufman and colleagues have shown a high yield (63%) of pathologic findings following UDS in the refractory pediatric patient with incontinence.3 Uroflowmetry can be useful in children with dysfunctional voiding who contract their external sphincters or pelvic floor muscles during micturition. Baseline and periodic UDS are performed in neurogenic bladder dysfunction (NBD) including myelomeningocele (MM, 90%) occult spinal dysraphism, sacral agenesis, imperforate anus, cloacal malformation, traumatic spinal cord injury, and central nervous system disorders. Infants with MM have three voiding patterns: synergic (26%), dyssynergic with or without diminished bladder compliance (37%), and complete denervation (36%).4 Detrusor sphincter dyssynergia (DSD) with associated high-end filling pressures ($ 40 cm of water) and highvoiding pressures of $ 80 to 100 cm of water leads to reflux and hydronephrosis unless UDS is performed along with early intervention with clean intermittent catheterization (CIC). UDS for NBD is repeated following a change in pharmacotherapy or surgery, new onset incontinence or hydroureteronephrosis, or recurrent symptomatic infections. Because deterioration in bladder function may occur silently, changes in the orthopedic or neurological examination warrant reassessment with UDS. Only one-third of infants with occult spinal dysraphism will have abnormal UDS irrespective of the neurological findings on examination. With increasing age, symptoms become more evident and include bowel and bladder dysfunction and alterations in lower extremity function. Recently, detrusor overactivity has been shown in all age groups with occult tethered cord syndrome.5-7 The earlier the surgical intervention, the greater the likelihood for functional improvement. Children with sacral agenesis involving partial or complete absence of vertebral bodies can remain silent until late childhood when incontinence, difficulty potty training, or urinary tract infection are evaluated. A flattened buttock with absence of the upper gluteal cleft may not be evident on early physical examination. UDS will often demonstrate detrusor acontractility and urethral sphincter denervation or overactive bladder (OAB) with DSD.8 Anorectal malformations may have genitourinary and spinal abnormalities, including tethered cord or iatrogenic injury, but may also have NBD without obvious etiology. These children may exhibit OAB with or without DSD (upper motor neuron lesion) or detrusor acontractility with sphincter denervation (lower motor neuron lesion).9 Posterior urethral valves (80%) often have bladder dysfunction with detrusor overactivity and diminished bladder compliance.10,11 Myogenic failure may be due to infrequent bladder emptying in conjunction with increased urinary output and is more often seen in the older age group. Uroflowmetry is noninvasive and can be used in patients who void spontaneously. The flow pattern is accurate as long as the volume is . 50% of maximum voided volume.12 The shape of the flow curve denotes the detrusor function, outlet resistance, or external sphincter dysfunction during micturition.13 Voiding patterns include a bell-shaped (normal), tower (OAB), plateau (outlet obstruction), staccato (sphincter activity during voiding), and interrupted curve (acontractile or underactive bladder).2 Perineal patch electromyography (EMG) can be used as an adjunct in determining the etiology of an abnormal flow pattern or postvoid residual urine.14 Postvoid residuals (PVRs) using bladder scanning should show residuals of # 20 cc or abnormal emptying is suspected in children. PVR is useful in patients on anticholinergic therapy. Invasive UDS is performed in the sitting or supine positions. Rectal and urethral catheters provide intraabdominal and intravesical pressures, respectively. The difference in these pressures is the detrusor pressure. A PVR is obtained in a non-CIC patient and patch EMG electrodes are positioned perineally in boys or paraurethrally in girls.15 EMG provides information on individual motor units at rest in response to sacral reflexes and during bladder filling and emptying with suspected or previously diagnosed NBD.9 During bladder filling, saline infusion at a temperature of 21° to 37°C is performed at a rate of 5% to 10% of the expected bladder capacity/minute.16,17 Bladder capacity for children is determined from the Hjälmås equation: expected bladder capacity (mL) 5 30 1 (age in years 3 30).16 For children with MM, the formula 24.5 3 age (years) 1 62 should be used.18 Children on CIC use the largest catheterized volume during the day over several days. At least two cycles of filling are required unless the child has no sensation and an NBD. The bladder has been sufficiently filled when the child has a strong urge to urinate, is uncomfortable, voiding starts, bladder pressures are . 40 cm of water, or the volume infused is . 150% of the expected capacity. The fluoroscopic video portion of the test permits correlation of detrusor ­pressures with urinary incontinence or reflux and also provides information on the bladder shape and the state of the sphincter during filling and emptying. Intrinsic or bladder neck dysfunction can also be assessed. Vol. 14 No. 1/2 • 2012 • Reviews in Urology • 37 40041700002_LiteratureReview.indd 37 20/07/12 2:11 PM Pediatric Urology continued Detrusor overactivity occurring during bladder filling is defined as an involuntary detrusor contraction . 15 cm of water from baseline.13 Bladder underactivity is also abnormal and recognized in patients who are filled to . 150% of their expected bladder capacity and have a poor or absent detrusor contraction. During filling, normal detrusor compliance is 10 cm of water at capacity, or 5% of the child’s normal capacity per cm of water, or about 20 cm of water at expected bladder capacity.12,13 Infants tend to have higher voiding pressures than children, and boys tend to have higher voiding pressures (by 5 to 15 cm of water) than girls.2,19 Urethral obstruction is suggested when there are high voiding pressures accompanied by poor flow rates. EMG pads may show a staccato voiding pattern. A low flow rate may be indicative of an anatomical obstruction and bladder emptying should be assessed. This review of pediatric urodynamics is comprehensive and provides an excellent source of classic references. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. Drzewiecki BA, Bauer SB. Urodynamic testing in children: indications, technique, interpretation and significance. J Urol. 2011;186:1190-1197. Yeung CK, Sihoe JDY, Bauer SB. Voiding dysfunction in children: nonneurogenic and neurogenic. In: Wein AJ, Kavoussi LR, Novick AC et al, eds. Campbell-Walsh Urology, 9th ed. Philadelphia; Saunders Elsevier; 2007:3604-3655. Kaufman MR, DeMarco RT, Pope JC 4th, et al. High yield of urodynamics performed for refractory nonneurogenic dysfunctional voiding in the pediatric population. J Urol. 2006;176:1835-1837. Bauer SB, Hallett N, Khoshbin S, et al. Predictive value of urodynamic evaluation in newborns with myelodysplasia. JAMA. 1984;252:650-652. Nogueira M, Greenfield SP, Wan J, et al. Tethered cord in children: a clinical classification with urodynamic correlation. J Urol. 2004;172(4 Pt 2):1677-1680; discussion 1680. Guerra LA, Pike J, Milks J, et al. Outcome in patients who underwent tethered cord release for occult spinal dysraphism. J Urol. 2006;176(4 Pt 2):1729-1732. Palmer LS, Richards I, Kaplan WE. Subclinical changes in bladder function in children presenting with nonurological symptoms of the tethered cord syndrome. J Urol. 1998;159:231-234. Guzman L, Bauer SB, Hallett M, et al. Evaluation and management of children with sacral agenesis. Urology. 1983;22:506-510. Bauer SB. Neurogenic bladder: etiology and assessment. Pediatr Nephrol. 2008;23:541-551. Bauer SB, Labib KB, Dieppa RA, Retik AB. Urodynamic evaluation of boy with myelodysplasia and incontinence. Urology. 1977;10:354-362. Peters CA, Bolkier M, Bauer SB, et al. The urodynamic consequences of posterior urethral valves. J Urol. 1990;144:122-126. Nijman RJM, Bower W, Butler U, et al. Diagnosis and management of urinary incontinence and encopresis in childhood. In: Abrams P, Cardozo L, Khoury S, et al, eds. 3rd International Consultation on Incontinence. Paris: Health Publications Ltd; 2005:967-1057. Nevéus T, von Gontard A, Hoebeke P, et al. The standardization of terminology of lower urinary tract function in children and adolescents: report from the Standardisation Committee of the International Children’s Continence Society. J Urol. 2006;176:314-324. Hoebeke P, Bower W, Combs A, et al. Diagnostic evaluation of children with daytime incontinence. J Urol. 2010;183:699-703. Lorenzo AJ, Wallis MC, Cook A, et al. What is the variability in urodynamic parameters with position change in children? Analysis of a prospectively enrolled cohort. J Urol. 2007;178:2567-2570. Hjälmås K. Urodynamics in normal infants and children. Scand J Urol Nephrol Suppl. 1988;114:20-27. Bael A, Lax H, de Jong TP, et al. The relevance of urodynamic studies for Urge syndrome and dysfunctional voiding: a multicenter controlled trial in children. J Urol. 2008;180:1486-1493; discussion 1494-1495. Palmer LS, Richards I, Kaplan WE. Age related bladder capacity and bladder capacity growth in children with myelomeningocele. J Urol. 1997;158(2 Pt 2):1261-1264. Ulla Sillén U, Abrahamsson K. Urodynamics in infants and children. In: Corcos J, Schick E (eds.), Textbook of Neurogenic Bladder, 2nd ed. London: Informa; 2008:483-497. Congenital Bladder Abnormalities Ellen Shapiro, MD, FACS, FAAP New York University School of Medicine, New York, NY [Rev Urol. 2012;14(1/2):38 doi: 10.3909/riu0550] © 2012 MedReviews®, LLC H iguchi and colleagues from the Mayo Clinic (Rochester, MN) published an interesting study to determine if ileal/colonic bladder augmentation in patients with congenital bladder abnormalities such as myelomeningocele, bladder exstrophy, or posterior urethral valves is an independent risk factor for bladder malignancy.1 These entities may have an inherent risk of neoplastic transformation in the absence of bladder augmentation. Records were reviewed from 1986 to 2010. Follow-up from augmentation (109 ileal and 44 colonic) was for at least 10 years with a median interval of 27 years. Controls were treated with clean intermittent catheritization and anticholinergic medications and were matched with the augmentation group for bladder dysfunction, sex, and age. This study of 153 patients showed no significant difference in the incidence of bladder cancer in the augmentation group (7 patients, 4.6%) vs control subjects (4 patients, 2.6%). When age at diagnosis, stage, mortality rate, or mean survival was analyzed, there was no significant difference between the two groups. The authors did find that chronic immunosuppression following renal transplantation significantly impacted the incidence of bladder cancer that was independent of augmentation status (15% vs 2.8%). In addition, those patients on immunosuppression who developed cancer also had a history of viral infections with cytomegalovirus, BK virus, and/or Epstein-Barr virus after transplantation. In the United States, approximately 2% of individuals will develop bladder cancer by age 78 years, with the majority presenting with localized disease.2 The current study found a 3.6% incidence of bladder cancer in patients with congenital bladder dysfunction presenting at a median age of 51 years. The data also show a twofold greater increase in bladder cancer in individuals with congenital bladder abnormalities vs the general population in which bladder cancer occurs at a much younger age with locally advanced disease or nodal metastases (81%). References 1. 2. Higuchi TT, Granberg CF, Fox JA, Husmann DA. Augmentation cystoplasty and risk of neoplasia: fact, fiction and controversy. J Urol. 2010;184:2492-2496. Horner MJ, Ries LAG, Krapcho M, et al. (eds). SEER Cancer Statistics Review, 1975-2006, National Cancer Institute. http://www.joplink.net/prev/201003/ref/16-001.html. Accessed February 28, 2012. 38 • Vol. 14 No. 1/2 • 2012 • Reviews in Urology 40041700002_LiteratureReview.indd 38 20/07/12 2:11 PM