title: In vitro comparison of changes in effective patient weight between purely laparoscopic and hand-assisted laparoscopic surgery.
abstract: OBJECTIVE
  Subclinical rhabdomyolysis (RM) has been reported to occur at a high frequency in patients who are undergoing hand-assisted laparoscopic (HAL) surgery. Compressive forces of the surgeon's hand pushing the patient down onto the operating table may increase the patient's effective weight, a factor that is correlated with risk of RM. The purpose of this study was to evaluate the changes in effective patient weight during pure laparoscopic (PL) and HAL surgery.
  
  
  METHODS
  Using an in vitro model, 10 subjects performed translocation and knot tying tasks with both PL and HAL techniques. Changes in weight were monitored using a dynamic industrial scale with real-time digital recording. The means of the average changes in effective weight during the different tasks were compared using the Wilcoxon signed rank test with a P value of <0.05 considered significant.
  
  
  RESULTS
  The mean of the average weight increases during translocation was 2.99 kg with HAL compared with 0.06 kg with PL (Z=4.3, P<0.05). The mean average weight increase during knot tying was 1.28 kg in HAL compared with 0.02 kg (Z=2.6, P<0.05) in PL. The mean maximum weight increase was 8.70 kg and 8.01 kg in HAL compared with 0.43 kg and 0.59 kg in PL during translocation and knot tying tasks, respectively (P<0.05 for each).
  
  
  CONCLUSIONS
  HAL surgery results in a significant increase in effective patient weight compared with PL surgery. This increased effective weight during HAL surgery may increase the risk for subsequent RM.
authors: Department of Urology, Loma Linda University, Loma Linda, California, USA.
authors: Marc W
authors: MW
authors: McAllister
authors: Ryan S
authors: RS
authors: Hsi
authors: Robert R
authors: RR
authors: Torrey
authors: Zachary
authors: Z
authors: Simmons
authors: Brenton D
authors: BD
authors: Baldwin
authors: D Duane
authors: DD
authors: Baldwin
mesh_terms: D001835:Body Weight; D058733:Hand-Assisted Laparoscopy / Q000009:adverse effects*; D006801:Humans; D008954:Models, Biological