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Gastric Transmural Pressure Measurements In Vivo: Implications for Natural Orifice Transluminal Endoscopic Surgery (NOTES®)
Abstracts
T1472 ‘‘No Scar’’ Small Bowel Resection Using Transcolonic NOTESÒ & Transabdominal Approach Elena Dubcenco, Teodor Grantcharov, Frank C. Eng, Catherine Streutker, Nancy N. Baxter, Ori D. Rotstein, Jeffrey P. Baker
T1474 Comparing Peritoneal Inflammation for NOTESÒ and Laparoscopy in Randomized Studies Erica A. Moran, Martha Hanes, Marianne Huebner, Christopher J. Gostout, Juliane Bingener
Background and Aims: NOTESÔ is in evolution. Fundamental NOTESÔ techniques and essential tools for performing ‘‘no scar’’ surgery still need to be developed. Our study was aimed to evaluate the feasibility of combined use of flexible and rigid instruments in performing surgical procedures without scars. Methods: This experimental study was conducted in a laboratory setting with the approval of the IACUC. Segmental small bowel resection was performed using porcine model. 1 non survival and 2 survival experiments were performed to date. A Veress needle was used to create pneumoperitoneum. The anterior colonic wall was used for colotomy. The endoscope was advanced into the peritoneal cavity. Without making skin incisions, 3 mm in diameter graspers were placed through the abdominal wall under direct endoscopic observation. A rigid liner stapler was advanced into the peritoneal cavity through the colon. A small incision was made in the bowel mesentery by a hook-knife. The stapler was positioned and fired creating a proximal cut end of the small bowel. The distal cut end of the bowel was created in the same manner. The segment of the bowel was resected by firing the stapler one more time, and then extracted through the colon. The two limbs of the small bowel were approximated by suturing. An enterotomy was created on the antimesenteric sides of each line. A side-to-side anastomosis was performed with another application of the stapler. The enterotomy was closed by suturing. The anastomosis was inspected for hemostasis and integrity. The colotomy was closed with endoclips. The endoscope was withdrawn. The transabdominal instruments were removed without placing the sutures. Results: Small bowel resection was successfully performed in all animals. The surgery time - 70 minutes. There was no mortality or complications. The animals recovered uneventfully, and survived the 2 weeks post-procedure period. They were placed on a liquid diet for 48 hours after the surgery followed by a regular diet. They remained healthy, and gained weight. Necropsy was performed 2 weeks after the surgery. On necropsy, evaluation of the abdominal skin revealed no scars. The peritoneal cavity was examined. No signs of infection, bleeding, perforations, and adhesions were noted. Endoscopic examination of the colotomy and anastomosis revealed complete healing that was confirmed by histopathology. Conclusions: The study has demonstrated the feasibility of small bowel resection using transcolonic NOTESÔ & transabdominal approach. Simultaneous use of flexible and rigid instruments was not only feasible but also facilitated performance of the operation yet leaving no scars.
Introduction: Smaller abdominal incisions in laparoscopy have led to decreasing peritoneal adhesions and inflammatory response. We hypothesized that Natural Orifice Translumenal Endoscopic Surgery (NOTES) would lead to an attenuated peritoneal response compared to laparoscopy. Methods: Pooled tissue analysis from two randomized IACUC approved studies was performed. A total of 49 female domestic swine were randomized to either 90-min diagnostic NOTES peritoneoscopy (nZ 17), 90-min interventional NOTES with transgastric mesh placement (nZ12), 45-min diagnostic endoscopy (no gastrotomy) followed by 45-min laparoscopic mesh placement (nZ14) or 90-min diagnostic laparoscopy (nZ6). On POD 1 and 2, serum and peritoneal WBC counts were measured. At 14 days, peritoneal cultures and tissue specimens (lung, liver, spleen) were obtained. Tissue H&E stains were reviewed by a blinded veterinary pathologist for presence and severity of inflammation (Severity score 0Z not present, 1Zmild, 2Zmoderate, 3Zsevere). The approximate KruskalWallis test for ordered contingency tables was used. Results: 46 of 49 swine underwent procedures as randomized and survived 14 days. Two NOTES animals died (airway loss POD 0/hemorrhagic gastritis POD 3); one NOTES mesh placement failed (endoscope failure). Intra-abdominal pressures during NOTES were significantly lower than during laparoscopy. There was no difference between clinical behavior, serum WBC, or peritoneal WBC between groups in the 2 studies. Four NOTES mesh animals but no laparoscopic mesh animals had mesh infections at necropsy. Histologic findings were pneumonia, liver fibrosis, and spleen capsulitis. No difference was seen for the incidence of each finding between groups, but severity was statistically different between groups (see table). When 90-min laparoscopy and endoscopyþ 45-min laparoscopic mesh were pooled and compared to diagnostic NOTES procedures, no difference in inflammation severity score was found for pneumonia (1.35 vs 1.44), liver (0.56 vs 0.69) or spleen (0.75 vs 1.12). Conclusion: More severe pneumonia was found in animals undergoing 90-min laparoscopic procedures with higher intraabdominal pressures. Intraperitoneal inflammation was most significant with transgastric mesh placement, likely due to the infections. Benefit from NOTES procedures may not be realized from an attenuated peritoneal inflammation but rather from decreased intraabdominal pressure. Mean group severity score by procedure
Histology
T1473 Gastric Transmural Pressure Measurements In Vivo: Implications for Natural Orifice Transluminal Endoscopic Surgery (NOTESÒ) David J. Desilets, Timothy J. Mader, John R. Romanelli, David Earle Introduction: There is currently no consensus on the best method of closing the gastrotomy in NOTES. One reason is that there is no agreement on the pressures acting on the gastric wall that might disrupt closure and result in leakage of gastric contents. Pressure measurements reported previously are relative intragastric pressures measured against ambient pressure in the lab, not versus intra-abdominal pressure, which is the true environment of the stomach. We hypothesized that forces acting on the stomach to promote disruption of a gastrotomy are much smaller than previously thought, and consist of the difference between the intragastric and extragastric pressures, that is, the gastric transmural pressure gradient. Methods: Twelve 35-45 kg swine were placed under general anesthesia. The pressures in the abdominal cavity and the gastric lumen were measured simultaneously. A highresolution manometric catheter was inserted into the stomach through a gastroscope, and an identical catheter was placed in the abdominal cavity through an abdominal wall puncture. Pressures were measured under various conditions including rest, simulated cough, and Valsalva maneuver. These measurements were performed with the stomach and abdomen empty, stomach inflated / abdomen empty, stomach empty / abdomen inflated to 12 mm Hg, stomach filled with 1 liter of water (to simulate a liquid meal) / abdomen empty, and stomach filled with water / abdomen at 12 mm Hg. Tracings of pressure measurements were overlaid graphically and also subtracted in real time, yielding a continuous (difference) measurement of the gastric transmural pressure gradient. Results: Measurements where both the stomach and abdomen were empty were hampered by artifact due to the manometry catheter impacting against tissue. When there was air or water around the catheters, good quality tracings were obtained. The average peak pressure generated in the abdomen during simulated cough was 35.4 mm Hg (stdev14.3) and during Valsalva it was 30.7 mm Hg (stdev 11.5) for an average of 2.9 seconds (stdev 0.6). The mean gastric transmural pressure gradient during these conditions was only 0.7 mm Hg (stdev 0.9). Conclusion: Forces acting on the gastrotomy to induce disruption and leakage are much smaller than previously believed, with an average pressure gradient of only 0.7 mm Hg. This has bearing on the durability and method of gastrotomy closure in NOTES.
www.giejournal.org
Lung (Pneumonia) Liver (Fibrosis/ Inflammation) Spleen (capsulitis)
Endoscopy Laparoscopy NOTES D Lap mesh (nZ6) (NZ16) (nZ14)
NOTES mesh (nZ12)
p-value (difference of severity by procedure)
2.0
1.4
1.1
1.3
0.017
0.4
0.7
0.6
1.5
0.019
0.7
1.2
0.8
1.7
0.058
T1475 Assessment of a Simple, Novel Endoluminal Method for Gastrotomy Closure in NOTESÒ Joo Ha Hwang, Renato V. Soares, Sang-Soo Lee, Huseyin Sinan, Jin Tae Jung, Martin I. Montenovo, Andrew S. Wright, Brant K. Oelschlager Introduction: A reliable method for gastrotomy closure in NOTES will be essential for NOTES to become viable clinically. Several methods have been reported; however, methods using existing endoscopic accessories have been ineffective. Specialized devices are in development but are not widely available. We report ex vivo results of a new method of gastrotomy closure using modified clips and endoloops. Methods: A standard NOTES gastrotomy with needle-knife incision followed by balloon-dilation with a 20 mm diameter balloon was performed in 20 ex vivo pig stomachs. Gastrotomies were closed using the conventional hand-sewn technique in 10 specimens and using the new retracted clip-assisted loop closure technique in 10 specimens. The retracted clip-assisted loop closure technique involves deploying 3-4 ResolutionÒ clips (modified by attaching a 90 cm length of suture string to the end of each clip) along the margin of the gastrotomy with one jaw on the serosal surface and the other jaw on the mucosal surface. The suture strings are then threaded through an endoloop. Traction is then applied to the strings causing the gastric wall to tent. The endoloop is then secured below the tip of the clips completing a full thickness gastrotomy closure. An air leak test was performed via insufflation with the endoscope. Fluid leak pressure was then measured for each specimen. Results: An air-tight seal was achieved in 100% of the specimens. Endoscopic image of the appearance of the closure (left image) and serosal image (right image) are provided. The mean leak pressure was 40.0 mmHg (SD 10.6) using the retracted clip-assisted loop closure technique and 56.8 mmHg
Volume 69, No. 5 : 2009 GASTROINTESTINAL ENDOSCOPY AB305
T1472 ‘‘No Scar’’ Small Bowel Resection Using Transcolonic NOTESÒ & Transabdominal Approach Elena Dubcenco, Teodor Grantcharov, Frank C. Eng, Catherine Streutker, Nancy N. Baxter, Ori D. Rotstein, Jeffrey P. Baker
T1474 Comparing Peritoneal Inflammation for NOTESÒ and Laparoscopy in Randomized Studies Erica A. Moran, Martha Hanes, Marianne Huebner, Christopher J. Gostout, Juliane Bingener
Background and Aims: NOTESÔ is in evolution. Fundamental NOTESÔ techniques and essential tools for performing ‘‘no scar’’ surgery still need to be developed. Our study was aimed to evaluate the feasibility of combined use of flexible and rigid instruments in performing surgical procedures without scars. Methods: This experimental study was conducted in a laboratory setting with the approval of the IACUC. Segmental small bowel resection was performed using porcine model. 1 non survival and 2 survival experiments were performed to date. A Veress needle was used to create pneumoperitoneum. The anterior colonic wall was used for colotomy. The endoscope was advanced into the peritoneal cavity. Without making skin incisions, 3 mm in diameter graspers were placed through the abdominal wall under direct endoscopic observation. A rigid liner stapler was advanced into the peritoneal cavity through the colon. A small incision was made in the bowel mesentery by a hook-knife. The stapler was positioned and fired creating a proximal cut end of the small bowel. The distal cut end of the bowel was created in the same manner. The segment of the bowel was resected by firing the stapler one more time, and then extracted through the colon. The two limbs of the small bowel were approximated by suturing. An enterotomy was created on the antimesenteric sides of each line. A side-to-side anastomosis was performed with another application of the stapler. The enterotomy was closed by suturing. The anastomosis was inspected for hemostasis and integrity. The colotomy was closed with endoclips. The endoscope was withdrawn. The transabdominal instruments were removed without placing the sutures. Results: Small bowel resection was successfully performed in all animals. The surgery time - 70 minutes. There was no mortality or complications. The animals recovered uneventfully, and survived the 2 weeks post-procedure period. They were placed on a liquid diet for 48 hours after the surgery followed by a regular diet. They remained healthy, and gained weight. Necropsy was performed 2 weeks after the surgery. On necropsy, evaluation of the abdominal skin revealed no scars. The peritoneal cavity was examined. No signs of infection, bleeding, perforations, and adhesions were noted. Endoscopic examination of the colotomy and anastomosis revealed complete healing that was confirmed by histopathology. Conclusions: The study has demonstrated the feasibility of small bowel resection using transcolonic NOTESÔ & transabdominal approach. Simultaneous use of flexible and rigid instruments was not only feasible but also facilitated performance of the operation yet leaving no scars.
Introduction: Smaller abdominal incisions in laparoscopy have led to decreasing peritoneal adhesions and inflammatory response. We hypothesized that Natural Orifice Translumenal Endoscopic Surgery (NOTES) would lead to an attenuated peritoneal response compared to laparoscopy. Methods: Pooled tissue analysis from two randomized IACUC approved studies was performed. A total of 49 female domestic swine were randomized to either 90-min diagnostic NOTES peritoneoscopy (nZ 17), 90-min interventional NOTES with transgastric mesh placement (nZ12), 45-min diagnostic endoscopy (no gastrotomy) followed by 45-min laparoscopic mesh placement (nZ14) or 90-min diagnostic laparoscopy (nZ6). On POD 1 and 2, serum and peritoneal WBC counts were measured. At 14 days, peritoneal cultures and tissue specimens (lung, liver, spleen) were obtained. Tissue H&E stains were reviewed by a blinded veterinary pathologist for presence and severity of inflammation (Severity score 0Z not present, 1Zmild, 2Zmoderate, 3Zsevere). The approximate KruskalWallis test for ordered contingency tables was used. Results: 46 of 49 swine underwent procedures as randomized and survived 14 days. Two NOTES animals died (airway loss POD 0/hemorrhagic gastritis POD 3); one NOTES mesh placement failed (endoscope failure). Intra-abdominal pressures during NOTES were significantly lower than during laparoscopy. There was no difference between clinical behavior, serum WBC, or peritoneal WBC between groups in the 2 studies. Four NOTES mesh animals but no laparoscopic mesh animals had mesh infections at necropsy. Histologic findings were pneumonia, liver fibrosis, and spleen capsulitis. No difference was seen for the incidence of each finding between groups, but severity was statistically different between groups (see table). When 90-min laparoscopy and endoscopyþ 45-min laparoscopic mesh were pooled and compared to diagnostic NOTES procedures, no difference in inflammation severity score was found for pneumonia (1.35 vs 1.44), liver (0.56 vs 0.69) or spleen (0.75 vs 1.12). Conclusion: More severe pneumonia was found in animals undergoing 90-min laparoscopic procedures with higher intraabdominal pressures. Intraperitoneal inflammation was most significant with transgastric mesh placement, likely due to the infections. Benefit from NOTES procedures may not be realized from an attenuated peritoneal inflammation but rather from decreased intraabdominal pressure. Mean group severity score by procedure
Histology
T1473 Gastric Transmural Pressure Measurements In Vivo: Implications for Natural Orifice Transluminal Endoscopic Surgery (NOTESÒ) David J. Desilets, Timothy J. Mader, John R. Romanelli, David Earle Introduction: There is currently no consensus on the best method of closing the gastrotomy in NOTES. One reason is that there is no agreement on the pressures acting on the gastric wall that might disrupt closure and result in leakage of gastric contents. Pressure measurements reported previously are relative intragastric pressures measured against ambient pressure in the lab, not versus intra-abdominal pressure, which is the true environment of the stomach. We hypothesized that forces acting on the stomach to promote disruption of a gastrotomy are much smaller than previously thought, and consist of the difference between the intragastric and extragastric pressures, that is, the gastric transmural pressure gradient. Methods: Twelve 35-45 kg swine were placed under general anesthesia. The pressures in the abdominal cavity and the gastric lumen were measured simultaneously. A highresolution manometric catheter was inserted into the stomach through a gastroscope, and an identical catheter was placed in the abdominal cavity through an abdominal wall puncture. Pressures were measured under various conditions including rest, simulated cough, and Valsalva maneuver. These measurements were performed with the stomach and abdomen empty, stomach inflated / abdomen empty, stomach empty / abdomen inflated to 12 mm Hg, stomach filled with 1 liter of water (to simulate a liquid meal) / abdomen empty, and stomach filled with water / abdomen at 12 mm Hg. Tracings of pressure measurements were overlaid graphically and also subtracted in real time, yielding a continuous (difference) measurement of the gastric transmural pressure gradient. Results: Measurements where both the stomach and abdomen were empty were hampered by artifact due to the manometry catheter impacting against tissue. When there was air or water around the catheters, good quality tracings were obtained. The average peak pressure generated in the abdomen during simulated cough was 35.4 mm Hg (stdev14.3) and during Valsalva it was 30.7 mm Hg (stdev 11.5) for an average of 2.9 seconds (stdev 0.6). The mean gastric transmural pressure gradient during these conditions was only 0.7 mm Hg (stdev 0.9). Conclusion: Forces acting on the gastrotomy to induce disruption and leakage are much smaller than previously believed, with an average pressure gradient of only 0.7 mm Hg. This has bearing on the durability and method of gastrotomy closure in NOTES.
www.giejournal.org
Lung (Pneumonia) Liver (Fibrosis/ Inflammation) Spleen (capsulitis)
Endoscopy Laparoscopy NOTES D Lap mesh (nZ6) (NZ16) (nZ14)
NOTES mesh (nZ12)
p-value (difference of severity by procedure)
2.0
1.4
1.1
1.3
0.017
0.4
0.7
0.6
1.5
0.019
0.7
1.2
0.8
1.7
0.058
T1475 Assessment of a Simple, Novel Endoluminal Method for Gastrotomy Closure in NOTESÒ Joo Ha Hwang, Renato V. Soares, Sang-Soo Lee, Huseyin Sinan, Jin Tae Jung, Martin I. Montenovo, Andrew S. Wright, Brant K. Oelschlager Introduction: A reliable method for gastrotomy closure in NOTES will be essential for NOTES to become viable clinically. Several methods have been reported; however, methods using existing endoscopic accessories have been ineffective. Specialized devices are in development but are not widely available. We report ex vivo results of a new method of gastrotomy closure using modified clips and endoloops. Methods: A standard NOTES gastrotomy with needle-knife incision followed by balloon-dilation with a 20 mm diameter balloon was performed in 20 ex vivo pig stomachs. Gastrotomies were closed using the conventional hand-sewn technique in 10 specimens and using the new retracted clip-assisted loop closure technique in 10 specimens. The retracted clip-assisted loop closure technique involves deploying 3-4 ResolutionÒ clips (modified by attaching a 90 cm length of suture string to the end of each clip) along the margin of the gastrotomy with one jaw on the serosal surface and the other jaw on the mucosal surface. The suture strings are then threaded through an endoloop. Traction is then applied to the strings causing the gastric wall to tent. The endoloop is then secured below the tip of the clips completing a full thickness gastrotomy closure. An air leak test was performed via insufflation with the endoscope. Fluid leak pressure was then measured for each specimen. Results: An air-tight seal was achieved in 100% of the specimens. Endoscopic image of the appearance of the closure (left image) and serosal image (right image) are provided. The mean leak pressure was 40.0 mmHg (SD 10.6) using the retracted clip-assisted loop closure technique and 56.8 mmHg
Volume 69, No. 5 : 2009 GASTROINTESTINAL ENDOSCOPY AB305