title: Is there an optimal contralateral testicular cut-off size that predicts monorchism in boys with nonpalpable testicles?
abstract: OBJECTIVE
  To identify a contralateral testicular cut-off size that would predict monorchism (intra-abdominal vanishing testis or inguinal/scrotal nubbin) in boys with unilateral nonpalpable testis (NPT).
  
  
  METHODS
  Boys with cryptorchidism, treated by a single surgeon at a tertiary care center from 2009 to 2013, were grouped based on intra-operative findings: boys with a solitary gonad (monorchism group, M) and two control groups: intra-abdominal testis (IAT) and palpable undescended testis (pUDT). Immediately before the procedures, the contralateral descended testes were measured using callipers. Boys with NPT underwent diagnostic laparoscopy. Sensitivity, specificity, positive and negative predictive values, likelihood ratios and receiver operating characteristic (ROC) curves were calculated.
  
  
  RESULTS
  Out of the 324 boys with cryptorchidism, 58 were found to have pUDT and 85 had NPT. Of these 85 boys with NPT, 50 had an IAT and 35 had monorchism. Mean ages at surgery for groups M, IAT and pUDT were similar (28.0, 31.3 and 30.4 months, respectively; P = 0.4). Mean length of the contralateral descended testes in groups M, IAT and pUDT was 24.3, 16.5 and 18.8 mm, respectively. Contralateral testicular cut-off lengths of 18, 19 and 20 mm had positive likelihood ratios (LR+) of 6.5, 7.4 and 10.1, respectively. The area under the ROC curve was 95% (95% CI: 91-100%).
  
  
  CONCLUSIONS
  A contralateral testicular cut-off length of 19-20 mm had the best accuracy in predicting monorchism in boys aged 11-30 months with unilateral NPT.
authors.affiliation: Department of Surgery, McMaster University, 1280 Main St W, HSC 4E19, Hamilton, Ontario L8S 4K1, Canada; McMaster Children's Hospital, Canada. Electronic address: braga@mcmaster.ca.
authors.forename: L H
authors.initials: LH
authors.lastname: Braga
authors.affiliation: Department of Surgery, McMaster University, 1280 Main St W, HSC 4E19, Hamilton, Ontario L8S 4K1, Canada. Electronic address: kims@medportal.ca.
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Surgery, McMaster University, 1280 Main St W, HSC 4E19, Hamilton, Ontario L8S 4K1, Canada. Electronic address: farrokh@mcmaster.ca.
authors.forename: F
authors.initials: F
authors.lastname: Farrokhyar
authors.affiliation: Department of Surgery, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada. Electronic address: armando.lorenzo@sickkids.ca.
authors.forename: A J
authors.initials: AJ
authors.lastname: Lorenzo
mesh_terms: D002675:Child, Preschool; D003456:Cryptorchidism / Q000473:pathology* / Q000601:surgery; D006061:Gonadal Dysgenesis, 46,XY / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D010535:Laparoscopy; D008297:Male; D056126:Orchiopexy; D009929:Organ Size; D010173:Palpation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D013737:Testis / Q000002:abnormalities* / Q000033:anatomy & histology / Q000601:surgery
keywords: Compensatory hypertrophy; Cryptorchidism; Monorchism; Nonpalpable testicle; Undescended testicle