Randomized blinded trial shows relative thrombocytopenia in natural orifice translumenal endoscopic surgery compared with standard laparoscopy in a porcine survival model

Background  Anecdotal reports of natural orifice translumenal endoscopic surgery (NOTES) procedures in patients are emerging. Whether the new procedure truly is less invasive is not known. Perioperative hematologic parameters during NOTES was compared with those during standard laparoscopy. Methods  For this study, 12 swine were randomized to transgastric peritoneoscopy with air or diagnostic laparoscopy using carbon dioxide. Arterial and venous catheters provided cardiopulmonary parameters and blood draws at baseline and up to 7 days postoperatively. The animals survived for 14 days. Data were analyzed by an investigator blinded to the procedure performed. Treatments were contrasted in terms of the mean outcome using a repeated measures linear model. Results  All experiments were successfully completed. No gastric leak or peritonitis resulted. One NOTES animal died of hemorrhagic gastritis on postoperative day 3 due to bleeding distant from the gastrotomy site. Two animals in the laparoscopy group and one animal in the endoscopy group experienced respiratory compromise requiring disinflation. A widening pulse pressure and lower bladder pressure were observed in the NOTES group compared with the laparoscopy group (p < 0.001). Pre- and postoperative laboratory results showed an increase in the white blood cell count (1,000/ml) from 16.83 ± 1.94 in the laparoscopy group and 15.17 ± 0.41 in the NOTES group at baseline to 24.17 ± 3.25 and 23.33 ± 3.88, respectively, on postoperative day 7, but no difference between the groups (p = 0.6). The platelet count (1,000/ml) showed a difference between the two groups, changing from 422.5 ± 97.49 to 446.33 ± 89.86 in the laparoscopy group and from 368 ± 105 to 299.5 ± 161.9 in the NOTES group (p = 0.03). Conclusion  Significant differences in measured but not clinically apparent parameters were encountered. A potentially significant thrombocytopenia clinically was encountered in the NOTES group. The physiologic impact of NOTES procedures beyond the absence of abdominal incisions should be investigated further. Presented at the 2nd international conference on NOTES, Boston, MA, 13–14 July, 2007.