Comparison of effects between prone position and variable oblique position on intra-abdominal pressure and surgical bleeding during discectomy

English Keywords:Intra-abdominal pressure  Prone position  Variable oblique position  Discectomy

English Abstract:

  【Abstract】 Objective：To compare the the effects of prone position and variable oblique position for posterior discectomy with regarding to intra-abdominal pressure and surgical bleeding．Method：A total of 156 patients undergoing single-level lumbar discectomy under general anesthesia during October 2007 and October 2009 were reviewed retrospectively．Patients were randomly divided into two groups with 78 cases in prone position（group A） and 78 cases in variable oblique position（group B）．All patients had their intra-abdominal pressure measured by a urinary bladder catheter，and the airway pressure including 5min postanesthesia induction（supine），5min postpositioning either in prone or oblique position and at the end of surgery before position alteration was documented respectively．The operation time and intraoperative bleeding were recorded and analyzed.Result：The operation time，intraoperative bleeding and average blood loss per minute were 74.4±13.8min，288.7±105.9ml and 3.8±0.7ml/min respectively in group A，while 59.2±10.0min，178.1±58.6ml and 3.0±0.5ml/min in group B，which showed statistically significant difference between two groups（P＜0.05）．The average intra-abdominal pressure in group A was 765±167Pa in the supine after anesthesia induction，1063±194Pa after positioning and 1074±191Pa at the end of surgery；while those were 788±170Pa，809±176Pa and 817±186Pa respectively in group B.The average airway pressure of group A was 14.1±1.2cmH2O for supine after anesthesia induction，17.3±1.9cmH2O after positioning and 17.6±2.0cmH2O at the end of surgery，while those were 14.2±1.5cmH2O，14.9±1.5cmH2O and 15.0±1.6cmH2O respectively in group B.There were no statistically significant difference between two groups either for intra-abdominal pressure or airway pressure in the supine position after anesthesia induction（P＞0.05）.In group A，the intra-abdominal pressure and airway pressure after positioning in prone position and at the end of surgery were significantly higher than those in the supine position（P＜0.05）.The intra-abdominal pressure and airway pressure in group A were significantly higher than those in group B after operative positioning and at the end of surgery（P＜0.05）.Correlation between the intraoperative bleeding and intra-abdominal pressure after positioning was statistically significant in group A（r=0.772，P＝0.000），but no significance in group B（r=0.287，P＝0.174）．Conclusion：Variable oblique position for posterior discectomy can reduce the compression to the thorax and abdomen，decrease intraoperative bleeding and shorten the operation time compared with the prone position．