title: A new valve-less trocar for urologic laparoscopy: initial evaluation.
abstract: BACKGROUND
  Laparoscopic trocars typically maintain pneumoperitoneum using trap door valves and silicone seals. However, valves and seals hinder passage of instruments, cause lens smudging, trap specimens and needles being removed from the abdominal cavity, and lose their seal with repeated instrument exchange.
  
  
  OBJECTIVE
  The aim of the present study was to evaluate the feasibility of a newly designed valve-less trocar.
  
  
  METHODS
  The valve-less trocar system creates a curtain of forced gas to maintain pneumoperitoneum. A separate unit filters smoke and recirculates captured escaping gas. The valve-less trocar was trialed in consecutive laparoscopic renal procedures of a single surgeon. Perioperative parameters and outcomes were collected and analyzed. The system's safety, advantages, and disadvantages were evaluated. Insufflation gas usage, elimination, and absorption were also measured.
  
  
  RESULTS
  Twenty-five patients underwent laparoscopic renal procedures using the valve-less trocar system. The procedures included laparoscopic partial, radical, and donor nephrectomy. The mean patient age was 58.26 years. The mean operative time was 125 minutes and the mean drop in Hb for the cohort was 2.34 g/dL (range 0.4-5.4). Two patients developed subcutaneous emphysema and of the two patients, one developed clinically insignificant pneumomediastinum postoperatively. There were no postoperative complications. The surgeon noted that the use of a valve-less trocar decreased smudging of laparoscopes, expeditiously evacuated smoke during cauterization leading to improved visualization, maintained pneumoperitoneum even while suctioning, and resulted in easy extraction of specimens and needles. It was noted that insufflation gas consumption was low and CO(2) elimination was not impaired.
  
  
  CONCLUSIONS
  Use of a valve-less trocar is safe. Decreased laparoscope smudging may translate into decreased operative times and reduced gas consumption may equate to cost savings. Additionally, its use brings several advantages and convenience to the operating surgeon. However, the system should be compared with conventional trocars prospectively to demonstrate clinical and economic benefit.
authors.affiliation: Smith Institute for Urology, Hofstra University Medical School, North Shore-LIJ Health System, New Hyde Park, New York, USA.
authors.forename: Amin S
authors.initials: AS
authors.lastname: Herati
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Atalla
authors.forename: Soroush
authors.initials: S
authors.lastname: Rais-Bahrami
authors.forename: Sero
authors.initials: S
authors.lastname: Andonian
authors.forename: Manish A
authors.initials: MA
authors.lastname: Vira
authors.forename: Louis R
authors.initials: LR
authors.lastname: Kavoussi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002245:Carbon Dioxide / Q000032:analysis; D005260:Female; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013525:Surgical Instruments; D013997:Time Factors; D013520:Urologic Surgical Procedures / Q000295:instrumentation*
chemical_list: D002245:Carbon Dioxide