title: The learning curve for access creation in solo ultrasonography-guided percutaneous nephrolithotomy and the associated skills.
abstract: OBJECTIVE
  The aim of the current trial was to evaluate the learning curve of access creation through solo ultrasonography (US)-guided percutaneous nephrolithotomy (PCNL), and clarify the technical details of the procedure.
  
  
  METHODS
  We evaluated the first 240 solo US-guided PCNLs performed by one surgeon at our institution. The data including the puncture procedure, access characteristics, access-related complications and stone-free rates were assessed in four sequential groups.
  
  
  RESULTS
  The puncture duration and number of times decreased from a mean of 4.4 min and 2.1 times for the first 60 patients to 1.3 min and 1.2 times for the last 60 patients. There was a significant decrease from 3.7 min and 1.8 times for the 61th-120th patients to 1.5 min and 1.3 times for the 121th-180th patients. All of the access-related severe bleeding appeared in the first 120 patients, while perforations only occurred in the first 60 patients. The stone-free rates were 68.3, 83.3, 90.0, and 93.3% for the four sequential groups.
  
  
  CONCLUSIONS
  The increase in experience lead to an improvement in the puncture duration and times, which accompany with better stone-free rates and lower complications. We propose that 60 operations are sufficient to gain competency, and a cutoff point of 120 operations will allow the surgeon to achieve excellence in the solo US-guided PCNL.
authors.affiliation: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Yu
authors.affiliation: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Rao
authors.affiliation: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ruan
authors.affiliation: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
authors.forename: Run
authors.initials: R
authors.lastname: Yuan
authors.affiliation: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
authors.forename: Chenglong
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
authors.forename: Haoyong
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Urology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China. 1025931346@qq.com.
authors.forename: Fan
authors.initials: F
authors.lastname: Cheng
mesh_terms: D000328:Adult; D016063:Blood Loss, Surgical; D002983:Clinical Competence; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000209:etiology; D007669:Kidney Calculi / Q000601:surgery*; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000009:adverse effects / Q000379:methods*; D061646:Operative Time; D011677:Punctures / Q000009:adverse effects; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
keywords: Calyx axis; Learning curve; PCNL; Ultrasonography