1. Pohl HG, Joyce GF, Wise M, Cilento BG Jr. Cryptorchidism and hypospadias. J Urol. 2007; 177:1646–1651.
2. Nelson CP, Park JM, Wan J, Bloom DA, Dunn RL, Wei JT. The increasing incidence of congenital penile anomalies in the United States. J Urol. 2005; 174(4 Pt 2):1573–1576.
3. Paulozzi LJ, Erickson JD, Jackson RJ. Hypospadias trends in two US surveillance systems. Pediatrics. 1997; 100:831–834.
4. Korvald C, Stubberud K. High odds for freedom from early complications after tubularized incised-plate urethroplasty in 1-year-old versus 5-year-old boys. J Pediatr Urol. 2008; 4:452–456.
5. Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis. 1987; 40:373–383.
6. Deyo RA, Cherkin DC, Ciol MA. Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. J Clin Epidemiol. 1992; 45:613–619.
7. United States Census Bureau [Internet]. Washington, DC: United States Census Bureau;c2015. cited 2014 Aug 23. Available from:
http://www.census.gov.
8. Budaus L, Abdollah F, Sun M, Morgan M, Johal R, Thuret R, et al. Annual surgical caseload and open radical prostatectomy outcomes: improving temporal trends. J Urol. 2010; 184:2285–2290.
9. Darling DA. The Kolmogorov-Smirnov, Cramer-Von Mises tests. Ann Math Stat. 1957; 28:823–838.
10. Shapiro SS, Wilk MB. An analysis of variance test for normality (complete samples). Biometrika. 1965; 52:591–611.
11. Anderson WF, Camargo MC, Fraumeni JF Jr, Correa P, Rosenberg PS, Rabkin CS. Age-specific trends in incidence of noncardia gastric cancer in US adults. JAMA. 2010; 303:1723–1728.
12. Panageas KS, Schrag D, Riedel E, Bach PB, Begg CB. The effect of clustering of outcomes on the association of procedure volume and surgical outcomes. Ann Intern Med. 2003; 139:658–665.
13. Borer JG, Bauer SB, Peters CA, Diamond DA, Atala A, Cilento BG Jr, et al. Tubularized incised plate urethroplasty: expanded use in primary and repeat surgery for hypospadias. J Urol. 2001; 165:581–585.
14. Tekgul S, Riedmiller H, Dogan HS, Hoebeke P, Kocvara R, Nijman JM, et al. Guidelines on pediatric urology. Arnhem (NL): European Association of urology;2013.
15. Springer A, Baskin LS. Timing of hypospadias repair in patients with disorders of sex development. Endocr Dev. 2014; 27:197–202.
16. Lu W, Tao Y, Wisniewski AB, Frimberger D, Kropp BP. Different outcomes of hypospadias surgery between north america, europe and china: is patient age a factor? Nephrourol Mon. 2012; 4:609–612.
17. Bush NC, Holzer M, Zhang S, Snodgrass W. Age does not impact risk for urethroplasty complications after tubularized incised plate repair of hypospadias in prepubertal boys. J Pediatr Urol. 2013; 9:252–256.
18. Flick RP, Sprung J, Harrison TE, Gleich SJ, Schroeder DR, Hanson AC, et al. Perioperative cardiac arrests in children between 1988 and 2005 at a tertiary referral center: a study of 92,881 patients. Anesthesiology. 2007; 106:226–237.
19. McCann ME, Schouten AN. Beyond survival; influences of blood pressure, cerebral perfusion and anesthesia on neurodevelopment. Paediatr Anaesth. 2014; 24:68–73.
20. Barbagli G, Perovic S, Djinovic R, Sansalone S, Lazzeri M. Retrospective descriptive analysis of 1,176 patients with failed hypospadias repair. J Urol. 2010; 183:207–211.
21. Lee OT, Durbin-Johnson B, Kurzrock EA. Predictors of secondary surgery after hypospadias repair: a population based analysis of 5,000 patients. J Urol. 2013; 190:251–255.
22. Miller DC, Saigal CS, Litwin MS. The demographic burden of urologic diseases in America. Urol Clin North Am. 2009; 36:11–27.
23. Perlmutter AE, Morabito R, Tarry WF. Impact of patient age on distal hypospadias repair: a surgical perspective. Urology. 2006; 68:648–651.
24. Bhat A, Mandal AK. Acute postoperative complications of hypospadias repair. Indian J Urol. 2008; 24:241–248.
25. Siu W, Daignault S, Miller DC, Dunn RL, Gilbert S, Weizer AZ, et al. Understanding differences between high and low volume hospitals for radical prostatectomy. Urol Oncol. 2008; 26:260–265.
26. Kelley-Quon LI, Tseng CH, Jen HC, Shew SB. Hospital type predicts surgical complications for infants with hypertrophic pyloric stenosis. Am Surg. 2012; 78:1079–1082.
27. Horowitz M, Salzhauer E. The 'learning curve' in hypospadias surgery. BJU Int. 2006; 97:593–596.
28. Frimberger D, Campbell J, Kropp BP. Hypospadias outcome in the first 3 years after completing a pediatric urology fellowship. J Pediatr Urol. 2008; 4:270–274.