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Yield pressure of the pyloric and cardiac sphincter during gastric distension in the baboon
A140S SSAT ABSTRACTS
GASTROENTEROLOGYVol. 114, No. 4
• S0151
FORCE FEEDBACK GRASPER HELPS RESTORE SENSE OF TOUCH IN MINIMALLY INVASIVE SURGERY. M. MacFarlane" J. Rosen*: B. Hannaford*" C. Pellegrini: M. Sinanan. Dept. of Surgery and Electrical Engineering*; University of Washington, Seattle, Washington. The age of Minimally Invasive Surgery (MIS) has brought forth astounding changes in the health care field. Less pain and quicker patient recovery have been demonstrated with several types of operations that were once performed by an open technique. With these dramatic changes have also come reports of complications. The decreased sense of touch is just one of several pitfalls in MIS which may lead to complications, such as gastric perforation and liver laceration. In prior work, we have developed and demonstrated a force feedback device that allows measurement of reflected forces of various biological tissues based on their intrinsic properties. The purpose of the current study is to demonstrate the ability of this device to restore some of the lost sense of touch in MIS which is present in open surgery. To demonstrate this ability, we used eight latex materials of identical dimensions but graded compliance, and asked 10 subjects to place them in increasing/decreasing order of compliance. They used three tools (their dominant gloved hand, a standard laparoscopic babcock grasper and our force feedback device fitted with the identical babcock grasper) to rate the latex samples in a blinded fashion. These conditions thus approximated the conditions of open surgery, MIS and MIS fitted with a force sensing device in terms of feeling tissues. Five MIS skilled surgeons and five non-surgeons participated in the study. Each subject rated the eight samples four times with each tool type (total of 12 data points per subject and 120 data points for the study). The difference of the chosen order from the known order is reported as the root mean square (RMS) of the difference. Statistical significance was reported as P<0.05. The results indicate that the force feedback device is significantly better than a standard babcock grasper at rating various tissue compliance, but was not as successful as a gloved hand (RMS = 2.76; 6.23; 1.34 respectively). There was no significant difference between surgeons and non-surgeons in rating compliance. We conclude that this device, with its capability of fully interchangeable tool tips, is able to partially restore a sense of touch in MIS which has been lost as compared to open surgery. This restored ability may thus potentially result in more efficient operations with fewer complications during MIS. In addition, these force feedback capabilities can also be incorporated into surgical simulation to create a more realistic simulation for training of future MIS skilled surgeons. • S0152 ANTITHROMBIN III REDUCES LEUKOCYTE-ENDOTHELIAL INTER-ACTION AFTER WARM HEPATIC ISCHEMIA IN RATS. Sasa-Marcel Maksan, Martha Maria Gebhard*, Marc-Oliver Maksan*, Christian Herfarth, Ernst Klar. Departments of Surgery and Experimental Surgery ~, University of Heidelberg, Department of Neurosurgery*, University of Bonn, Germany.
Objective: Antithrombin III (AT III) has been demonstrated to improve mucosal blood flow after reperfusion of the small intestine. It was the aim of this study to analyze hepatic microcirculation and leukocyte-endothelia ! interaction after warm liver ischemia and reperfusion. Material and methods: Warm hepatic ischemia was induced in male Wistar rats (n=12, 250-280 g) by occluding blood vessels and bile duct of the left middle lobe. The AT III group (n=6) was treated with 250 IU AT III/kg body weight 30 min prior to ischemia. Ischemia was performed for 60 min. 30 min after reperfusion hepatic microcirculation was analyzed by intravital fluorescence microscopy with respect to sinusoidal perfusion and leukocyte adherence. Significance analysis was done by Wilcoxon-Mann-Whitney-U-test. Results: There was a significant increase in hepatic microcirculation in the AT III group. The leukocyte-endothelial interaction was markedly reduced by AT III (p<0,05). Percentage of non-perfused acini Adherent leukocytes in sinusoids (per mm2 liver surface) Adherent leukocytes in venules (per mm2 endothelial surface)
Controls 7,33 -+ 1,75 47,44 ± 3,19
AT III Group 3,83 ± 1,67 35,78 ± 1,24
p-value < 0,05 < 0,01
217,19--.15,7
174,80-+9,16
<0,05
preoperative radiation therapy, a better understanding is needed as to what is an acceptable distal margin. We examined our experience with high dose preoperative external irradiation and sphincter preservation surgery between 1976 and 1994. Using a four field box technique, patients were treated with 1.8-2.5 Gy fractions to a total of 45-60 Gy over 4.5-6 weeks. Following a period 4.5-8 weeks, to allow for maximal downstaging, surgery was performed. Decisions regarding sphincter preservation were based on the cancer after radiation. In 226 patients (mean age 62 y.o.; 85 women) local recurrence rates and distal margins were evaluated in 222 patients. In four patients, data on the distal margin was unavailable, but none had a local recurrence. There were no positive distal margins. There was no operative mortality or major radiation-related morbidity. The average follow up was 59 months. Local recurrence rates are shown below.
Local Recurrence
0.1-0.5 12% (2/16)
Distal Margin of Resection (cm) >0.5-1 >1-2 2-3 >3-4.5 >4.5-6 >6 0 16% 9.5% 12% 0 12% (0/10) (10/61) (4/42) (6/52) (0/16) (3/25)
Using a Chi-Square test for trend, we found no significant differences in local recurrence as the distal margin varied. By comparing groups with margins > vs. -< 6 cm, 4.5 cm, 2 cm, 1 cm, and 5 mm, there was no statistical difference in local recurrence even when stratified by stage of disease. Our experience indicates that lesser distal margins are acceptable in rectal cancer treated with high dose preoperative external irradiation. It appears safe to base decisions regarding an acceptable distal margin for sphincter preservation on the characteristics of the cancer after radiation, allowing for the maximal benefit of tumor downstaging. S0154
ACCURACY OF ENDOSCOPIC ULTRASONOGRAPHY IN THE PREOPERATIVE STAGING OF RECTAL CANCER, P Marone, F Petmlio. M de Bellis, GB Rossi, PF Malone and AM Tempesta. Endoscopy Unit, National Cancer Institute of Naples, Italy. Introduction: Endoscopic ultrasonography (EUS) is an imaging technique
which differentiates individual layers of the rectal wall and visualizes local lymph nodes. It allows the evaluation of longitudinal and circumferential spread of the tumor and the diagnosis of local lymph nodes metastases. EUS was shown to be very accurate in the locoregional staging of rectal cancer. We evaluated the accuracy of EUS in the preoperative staging of patients with rectal cancer at our institution. Patients and methods: From January 1994 to December 1996, 82 patients with rectal cancer were examined by means of EUS and CT scan during the preoperative staging at our institution. Patients who were not operated on (#10) and those who underwent preoperative radiotherapy (#29) were excluded from the study. Therefore, only 43 patients (29 males, 14 females with a mean age of 60 years; range 42:80) were evaluated. EUS was performed in all cases using an echocolonoscope Olympus ® CF UM 20, with a 7.5 MHz radial scanner. All patients underwent CT scan of the abdomen and pelvis preoperatively. Results: EUS showed an overall accuracy of 81% for the T stage (including non trasversable stenotic tumors) and of 68% for the N stage. On the other hand, the overall accuracy of the CT scan was 41% for the T stage and 51% for the N stage. The accuracy of EUS for the T stage increased from 81 to 87.5% when we excluded from the analysis those cases with non trasversable stenotic cancer. In staging tumors EUS showed an accuracy of 80% for both T1 and T2, 83% for T3 and 80% for T4 stage. Misstaging (19%) was due in 4 cases to understaging and in the other 4 cases to overstaging. Understaging occurred mainly in stenotic non trasversable tumors (3 out of 4 cases). Finally, EUS was highly accurate (89%) in differentiating T1 from T2-4 tumors. On the other hand, the CT scan was unable to detect the tumor in 17 patients (39.5%) and showed a misstaging rate of 53%, mainly due to understaging. Conclusions: Our data, according to the results of previous studies, shows EUS to be very accurate in the locoregional staging of rectal cancer and suggests that this imaging technique should have a definite role in the preoperative evaluation of patients with rectal cancer. S0155
Conclusion; The results of the current study demonstrated that pretreatment with AT III significantly improves microcirculation after warm liver ischemia and reperfusion. The reduction of leukocyte-endothelial interaction represents the main mechanism. • S0153 RECTAL CANCER: THE IMPACT OF HIGH DOSE PREOPERATIVE IRRADIATION ON DISTAL SURGICAL MARGINS. J. Marks, J. Cotter, G. Marks, M. Mohiuddin,* Dept. of Surgery, Allegheny University Hospital, Philadelphia, PA; *Dept. of Radiation Medicine, University of Kentucky, Lexington, KY. Traditional data regarding an adequate distal margin of resection in rectal cancer has been based on surgical treatment alone. With the advent of
YIELD PRESSURE OF THE PYLORIC AND CARDIAC SPHINCTER DURING GASTRIC DISTENSION IN THE BABOON. RJ. Mason, G Perdikis. TR. DeMeester, CL Filivi. TM Sema. JJ Nigro, JA Hagen, CG Bremner. Department of Surgery, University of Southern California, Los Angeles, CA. The cardia functions to vent the stomach of swallowed gas and to prevent reflux of gastric contents into the esophagus, while the pylorus controls gastric emptying and prevents the reflux of duodenal contents into the stomach. The purpose of this study was to investigate the relationship and the yield pressure of these two sphincters following gastric distension. Method: Seventeen baboons had distension of the stomach With gas (CO2) through the central lumen of a manometry catheter using a laparoscopic gas insufflator. Gastric pressure was increased incrementally in a stepwise fashion every 2 minutes, while monitoring gas flow and volume delivered. Continuous pressure recordings were obtained of the esophagus, stomach and cardia of the anaesthetized animals in an upright position. Yield of the cardiac
April 1998
SSAT A1409
sphincter was defined by the permanent loss of the gastroesophageal pressure gradient. Yield at the pyloric sphincter was defined by continuous flow on the gas insufflator while maintaining the gastroesophageal pressure gradient. Results: No esophageal venting episodes were observed at resting gastric pressure and volume. Gastric distension induced an increased frequency of venting episodes. In 13 (76%) animals the sphincter to yield was the cardia and in 4 (24%) the pylorns. The intragastric yield pressure is shown in the Table. The median venting volume was 33 -+38 ml per episode. Yield Sphincter Cardiac Pyloric p = .253 13vs. "/
n Yield Pressure (mmHg) 13 14 -+ 6.513 4 16 + 7.3"/ Median _+Interquartile Range
Conelusion: A non-yielding pyloric sphincter encourages incompetency at the cardia sphincter during gastric distension. This mechanism may be involved in the pathogenesis of postprandial gastroesophageal reflux. S0156 ACCUMULATION OF PItOSPHATIDYLCttOLINE HYDOPEROXIDE IN TIlE INTF~TINAL MUCOSA OF RATS ISCHEMIA / REPERFUSION MODEL. T.Masuko, I.Sasaki, Y.Funayama, H.Naito, K.Fukushima, C.Shibata, S.Matsuno, T.Miyazawa. First Department of Surgery, School of Medicine, Applied Biochemistry, School of Agliculture, Tohoku University, Sendal, Japan.
Background and Aim: Thiobarbituric acid reactant (TBARS) has been used as a popular method for estimating the oxidized lipids. But this assay is neither specific for the hydroperoxy group nor stoichiometric. The detection of a specific product of lipid peroxidatinn in ischemia/reperfusion injury in intestinal mucosa has not been estimated. Chemiluminescence detection-high performance liquid chromatography (CL-HPLC) is a system established in our labolatories to quantify a specific primary lipid product of the peroxidation. The aim of this study is to evaluate phosphatidylcholine hydropernxide (PCOOH), in comparison with TBARS in rat intestinal ischemia / reperfusion model. Methods: Under pentnbarbital anesthesia, six male Sprague-Dawley rats (200 to 240g) underwent 30 minutes of occlusive small intestinal ischemia followed by 30 to 360 minutes of reperfusinn (I/R group). Other 6 rats underwent 30 minutes of ischemia without reperfusion (Isch group). Non ischemic bowel (6 rats) was harvested as a control. Mucnsa was scraped and stored at -g0°c. Grade of the mucnsal injury (GMI) was scored histologically using Hematnxirin-Ensin staining. Mucosal levels of PCOOH and TBARS were measured by CL-HPLC and Ohkawa's method, respectively. Results: GMI was more severe in I/R group compared with Isch group. There were no significant differece in TBARS levels between the three groups (Fig). PCOOH level increased in I/R group (30 rain), and there were no significant difference between control group and Isch group .Conclusion: PCOOH is accumulated in intestinal mucosa after the ischemia / reperfusion in rats. We believe that detection of PCOOH using CL-HPLC will shed light on the evaluation of lipid peroxidatinn in the intestinal mucosa.
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S0157 MACROSCOPIC APPEARANCE OF TUMOR AND PANCREATIC INVASION ARE USEFUL PREDICTORS OF SURVIVAL IN SURGICAL TREATMENT OF AMPULLARY CARCINOMA. G. Matsumoto 1.2, K. Arai 1, T. Tsuchiyal 1, R. Anzai l, M. Takahashi 1, S. Matsuno 2, and T. Yamazaki 1. Department of Surgery, Sendai City Medical Center I and First Department of Surgery, Tohoku University School of Medicine 2, Sendal, Japan. Aims: To determine what factors affected the prognosis in patients with ampullary carcinoma and to investigate the possibility of preoperative prediction of the long-term outcome in these patients. Patients and Methods: From 1983 to 1997, 36 patients with ampullary carcinoma underwent surgical resection in Sendai City Medical Center. Pancreatodundenectomy including pylorus-preserving procedure was performed in 35 patients and one patient underwent local resection of the ampulla of Vater. Pathological factors influencing the prognosis were evaluated retrospectively. Results: Overall 5-year survival rate was 66.6%. Histnpathological factors favorably influencing the survival were negative lymph node metastasis (p < 0.0001), no pancreatic invasion (p < 0.01), and no duodenal invasion (p < 0.05). Tumor differentiation did not affect the prognosis. When patients were classified into the two groups depending on macroscopic appearances of tumor whether ulceration was observed or not, prognosis of the patients of non-ulceration type was significantly better than that of ulceration type
(5-year survival: 93.3% vs. 10.9%, p < 0.0001). In addition, all of the 17 patients with non-ulceration type tumor and no pancreatic invasion had no lymph node metastasis at operation and postoperative recurrence was not observed in these patients. Conclusion: Lymph node status is an important prognostic factor but difficult to be diagnosed preoperatively. Our study showed that macroscopic appearance of tumor and pancreatic invasion were correlated with the survival rate, which could be evaluated by endoscopy and endoscopic ultrasonography. These suggest that preoperative evaluation of macroscopic appearance of tumor and pancreatic invasion is useful for prediction of survival in patients with ampullary carcinoma. • S0158 CHARACTERIZATION AND REDUCTION OF ISCHEMIAJ REPERFUSION-INJURY AFTER EXPERIMENTAL PANCREAS TRANSPLANTATION. H. Mayer, J. Schmidt, J. Thies, E. Ryscbich, M.M. Gebhard*, Ch. Herfarth, E. Klar; Department of Surgery and *Department of Experimental Surgery, University of Heidelberg, Germany. Reperfusion injury after pancreas transplantation with subsequent disturbance of microcirculation is a common cause of early graft pancreatitis. The aim of this study was to quantify the pancreatic microcirculation after pancreas transplantation in correlation to cold ischemia time. In the second step the effect of N-Acetylcysteine (NAC) was tested in the impaired microcirculation. Methods: In male Lewis rats we performed pancreas transplantation according to the technique of Lee in three different groups. Group 1 and 2 received no special treatment. Cold ischemia time was 1.5 (group 1) and 16 hours (group 2+3). In group 3, donor and recipient were treated with NAC (300 mg/kilogram body weight). In all three groups the grafts were perfused and stored in UW-solution. In group 1 and 2 grafts were rinsed with saline solution, grafts of group 3 were rinsed with a saline solution containing 3mg/ml NAC before implantation. 1.5 hours after reperfusion graft microcirculation was quantified by means of intravital microscopy. Rhodamine-labeled leucocytes, FITC-labeled erythrocytes and FITC-labeled albumin were used as fluorochromes. Results: After a cold ischemia time of 16 hours functional capillary density (FCD) was reduced to 106 - 44 cm/cm2 compared to 155-+ 28 cm/cm2 after cold ischemia of 1.5 hours (p<0.05). Treatment with NAC led to a FCD of 149 -+ 18 cm/cm2 (p=0.05 compared with 16 hours without treatment). Erythrocyte velocity was 0.83 -+ 0.12 mm/s (1.5 hours); 0.52 _+0.13 (16 hours) and 0.66 + 0.12 (16 hours +NAC; p<0.05 NAC vs. control 16 hours). Leucocyte-endothelium interaction was also significantly aggravated after 16 hours ischemia time vs. 1.5 hours (10.8 vs. 7.1 Rollers/100ktm venule). NAC reduced teucocyte-endothelium-interaction to 7.0 Rollers/1001am venule (p<0.05). Conclusions: lschemia-/ Reperfusion injury after experimental pancreas transplantation is characterized by a disturbance of pancreatic microcirculation exhibiting a correlation to the duration of cold ischemia time. Erythrocyte velocity and functional capillary density were reduced, leucocyte-endothelium interaction was enhanced after a cold ischemia time of 16 hours compared to 1.5 hours. Treatment of donor and recipient with NAC resulted in a stabilisation of capillary perfusion. The clinical relevance of NAC in the reduction of ischemia/ reperfusion injury after pancreas transplantation remains to be investigated. S0159 RESULTS OF LAPAROSCOPIC NISSEN FUNDOPLICATION IN A TEACHING INSTITUTION. W. Scott Melvin. Ziad E. Abouezzi, William J. Schirmer and E. Christopher Ellison. Department of Surgery, The Ohio State University, Columbus, Ohio. We have been concerned that the change from open surgery to laparoscopy for advanced gastrointestinal surgery have a deleterious effect on the training of our residents. We specifically evaluated the exposure of our senior residents in the performance of antireflux procedures over the period over which this change has occurred. We analyzed our database on patients who underwent laparoscopic antireflux surgery from Jan. 1994 till Sept. 1997. Data on patients' age, operative time, intraoperative and postoperative complications, conversion rate, length of stay and readmission rate were analyzed. Case logs of graduating chief residents were also reviewed. One hundred-fifteen patients were included in the study with a mean age of 43 years (range from 19 to 73), all requiring medical treatment with an average duration of symptoms of 68 months. There were 106 Nissen, 6 Toupet and 3 Rosetti fundoplications. Only the first 20 were performed by two attending surgeons, after that residents were involved. Operating time averaged 196 min, there were no intraoperative complications. Conversion rate was 5.2% (6 patients). Mean length of stay was 2.1 days. 16 minor complications occurred (fever 6, respiratory 4, prolonged ileus 3, urinary 2, cardiac 2 and headache 1). There were 8 persistent dysphagia, 10 readmissions (8.6%) for poor oral intake 8, pneumonia 1 and foreign body impaction 1, and 3 reoperations. Over the same period of time, the total number of antireflux procedures done by a graduating chief resident up to the PGY5 level remained basically the same (mean total of 13.2) with 28.5% decrease (mean of 10.5 to 7.5) of open procedures and 111% increase of laparoscopic procedures (mean of 2.7 to 5.7). CONCLUSION: Laparoscopic antireflux procedures can be safely performed in an academic center. The advent of advanced laparoscopy did not decrease . the operative experience of surgical trainees in the field of antireflux procedures.
GASTROENTEROLOGYVol. 114, No. 4
• S0151
FORCE FEEDBACK GRASPER HELPS RESTORE SENSE OF TOUCH IN MINIMALLY INVASIVE SURGERY. M. MacFarlane" J. Rosen*: B. Hannaford*" C. Pellegrini: M. Sinanan. Dept. of Surgery and Electrical Engineering*; University of Washington, Seattle, Washington. The age of Minimally Invasive Surgery (MIS) has brought forth astounding changes in the health care field. Less pain and quicker patient recovery have been demonstrated with several types of operations that were once performed by an open technique. With these dramatic changes have also come reports of complications. The decreased sense of touch is just one of several pitfalls in MIS which may lead to complications, such as gastric perforation and liver laceration. In prior work, we have developed and demonstrated a force feedback device that allows measurement of reflected forces of various biological tissues based on their intrinsic properties. The purpose of the current study is to demonstrate the ability of this device to restore some of the lost sense of touch in MIS which is present in open surgery. To demonstrate this ability, we used eight latex materials of identical dimensions but graded compliance, and asked 10 subjects to place them in increasing/decreasing order of compliance. They used three tools (their dominant gloved hand, a standard laparoscopic babcock grasper and our force feedback device fitted with the identical babcock grasper) to rate the latex samples in a blinded fashion. These conditions thus approximated the conditions of open surgery, MIS and MIS fitted with a force sensing device in terms of feeling tissues. Five MIS skilled surgeons and five non-surgeons participated in the study. Each subject rated the eight samples four times with each tool type (total of 12 data points per subject and 120 data points for the study). The difference of the chosen order from the known order is reported as the root mean square (RMS) of the difference. Statistical significance was reported as P<0.05. The results indicate that the force feedback device is significantly better than a standard babcock grasper at rating various tissue compliance, but was not as successful as a gloved hand (RMS = 2.76; 6.23; 1.34 respectively). There was no significant difference between surgeons and non-surgeons in rating compliance. We conclude that this device, with its capability of fully interchangeable tool tips, is able to partially restore a sense of touch in MIS which has been lost as compared to open surgery. This restored ability may thus potentially result in more efficient operations with fewer complications during MIS. In addition, these force feedback capabilities can also be incorporated into surgical simulation to create a more realistic simulation for training of future MIS skilled surgeons. • S0152 ANTITHROMBIN III REDUCES LEUKOCYTE-ENDOTHELIAL INTER-ACTION AFTER WARM HEPATIC ISCHEMIA IN RATS. Sasa-Marcel Maksan, Martha Maria Gebhard*, Marc-Oliver Maksan*, Christian Herfarth, Ernst Klar. Departments of Surgery and Experimental Surgery ~, University of Heidelberg, Department of Neurosurgery*, University of Bonn, Germany.
Objective: Antithrombin III (AT III) has been demonstrated to improve mucosal blood flow after reperfusion of the small intestine. It was the aim of this study to analyze hepatic microcirculation and leukocyte-endothelia ! interaction after warm liver ischemia and reperfusion. Material and methods: Warm hepatic ischemia was induced in male Wistar rats (n=12, 250-280 g) by occluding blood vessels and bile duct of the left middle lobe. The AT III group (n=6) was treated with 250 IU AT III/kg body weight 30 min prior to ischemia. Ischemia was performed for 60 min. 30 min after reperfusion hepatic microcirculation was analyzed by intravital fluorescence microscopy with respect to sinusoidal perfusion and leukocyte adherence. Significance analysis was done by Wilcoxon-Mann-Whitney-U-test. Results: There was a significant increase in hepatic microcirculation in the AT III group. The leukocyte-endothelial interaction was markedly reduced by AT III (p<0,05). Percentage of non-perfused acini Adherent leukocytes in sinusoids (per mm2 liver surface) Adherent leukocytes in venules (per mm2 endothelial surface)
Controls 7,33 -+ 1,75 47,44 ± 3,19
AT III Group 3,83 ± 1,67 35,78 ± 1,24
p-value < 0,05 < 0,01
217,19--.15,7
174,80-+9,16
<0,05
preoperative radiation therapy, a better understanding is needed as to what is an acceptable distal margin. We examined our experience with high dose preoperative external irradiation and sphincter preservation surgery between 1976 and 1994. Using a four field box technique, patients were treated with 1.8-2.5 Gy fractions to a total of 45-60 Gy over 4.5-6 weeks. Following a period 4.5-8 weeks, to allow for maximal downstaging, surgery was performed. Decisions regarding sphincter preservation were based on the cancer after radiation. In 226 patients (mean age 62 y.o.; 85 women) local recurrence rates and distal margins were evaluated in 222 patients. In four patients, data on the distal margin was unavailable, but none had a local recurrence. There were no positive distal margins. There was no operative mortality or major radiation-related morbidity. The average follow up was 59 months. Local recurrence rates are shown below.
Local Recurrence
0.1-0.5 12% (2/16)
Distal Margin of Resection (cm) >0.5-1 >1-2 2-3 >3-4.5 >4.5-6 >6 0 16% 9.5% 12% 0 12% (0/10) (10/61) (4/42) (6/52) (0/16) (3/25)
Using a Chi-Square test for trend, we found no significant differences in local recurrence as the distal margin varied. By comparing groups with margins > vs. -< 6 cm, 4.5 cm, 2 cm, 1 cm, and 5 mm, there was no statistical difference in local recurrence even when stratified by stage of disease. Our experience indicates that lesser distal margins are acceptable in rectal cancer treated with high dose preoperative external irradiation. It appears safe to base decisions regarding an acceptable distal margin for sphincter preservation on the characteristics of the cancer after radiation, allowing for the maximal benefit of tumor downstaging. S0154
ACCURACY OF ENDOSCOPIC ULTRASONOGRAPHY IN THE PREOPERATIVE STAGING OF RECTAL CANCER, P Marone, F Petmlio. M de Bellis, GB Rossi, PF Malone and AM Tempesta. Endoscopy Unit, National Cancer Institute of Naples, Italy. Introduction: Endoscopic ultrasonography (EUS) is an imaging technique
which differentiates individual layers of the rectal wall and visualizes local lymph nodes. It allows the evaluation of longitudinal and circumferential spread of the tumor and the diagnosis of local lymph nodes metastases. EUS was shown to be very accurate in the locoregional staging of rectal cancer. We evaluated the accuracy of EUS in the preoperative staging of patients with rectal cancer at our institution. Patients and methods: From January 1994 to December 1996, 82 patients with rectal cancer were examined by means of EUS and CT scan during the preoperative staging at our institution. Patients who were not operated on (#10) and those who underwent preoperative radiotherapy (#29) were excluded from the study. Therefore, only 43 patients (29 males, 14 females with a mean age of 60 years; range 42:80) were evaluated. EUS was performed in all cases using an echocolonoscope Olympus ® CF UM 20, with a 7.5 MHz radial scanner. All patients underwent CT scan of the abdomen and pelvis preoperatively. Results: EUS showed an overall accuracy of 81% for the T stage (including non trasversable stenotic tumors) and of 68% for the N stage. On the other hand, the overall accuracy of the CT scan was 41% for the T stage and 51% for the N stage. The accuracy of EUS for the T stage increased from 81 to 87.5% when we excluded from the analysis those cases with non trasversable stenotic cancer. In staging tumors EUS showed an accuracy of 80% for both T1 and T2, 83% for T3 and 80% for T4 stage. Misstaging (19%) was due in 4 cases to understaging and in the other 4 cases to overstaging. Understaging occurred mainly in stenotic non trasversable tumors (3 out of 4 cases). Finally, EUS was highly accurate (89%) in differentiating T1 from T2-4 tumors. On the other hand, the CT scan was unable to detect the tumor in 17 patients (39.5%) and showed a misstaging rate of 53%, mainly due to understaging. Conclusions: Our data, according to the results of previous studies, shows EUS to be very accurate in the locoregional staging of rectal cancer and suggests that this imaging technique should have a definite role in the preoperative evaluation of patients with rectal cancer. S0155
Conclusion; The results of the current study demonstrated that pretreatment with AT III significantly improves microcirculation after warm liver ischemia and reperfusion. The reduction of leukocyte-endothelial interaction represents the main mechanism. • S0153 RECTAL CANCER: THE IMPACT OF HIGH DOSE PREOPERATIVE IRRADIATION ON DISTAL SURGICAL MARGINS. J. Marks, J. Cotter, G. Marks, M. Mohiuddin,* Dept. of Surgery, Allegheny University Hospital, Philadelphia, PA; *Dept. of Radiation Medicine, University of Kentucky, Lexington, KY. Traditional data regarding an adequate distal margin of resection in rectal cancer has been based on surgical treatment alone. With the advent of
YIELD PRESSURE OF THE PYLORIC AND CARDIAC SPHINCTER DURING GASTRIC DISTENSION IN THE BABOON. RJ. Mason, G Perdikis. TR. DeMeester, CL Filivi. TM Sema. JJ Nigro, JA Hagen, CG Bremner. Department of Surgery, University of Southern California, Los Angeles, CA. The cardia functions to vent the stomach of swallowed gas and to prevent reflux of gastric contents into the esophagus, while the pylorus controls gastric emptying and prevents the reflux of duodenal contents into the stomach. The purpose of this study was to investigate the relationship and the yield pressure of these two sphincters following gastric distension. Method: Seventeen baboons had distension of the stomach With gas (CO2) through the central lumen of a manometry catheter using a laparoscopic gas insufflator. Gastric pressure was increased incrementally in a stepwise fashion every 2 minutes, while monitoring gas flow and volume delivered. Continuous pressure recordings were obtained of the esophagus, stomach and cardia of the anaesthetized animals in an upright position. Yield of the cardiac
April 1998
SSAT A1409
sphincter was defined by the permanent loss of the gastroesophageal pressure gradient. Yield at the pyloric sphincter was defined by continuous flow on the gas insufflator while maintaining the gastroesophageal pressure gradient. Results: No esophageal venting episodes were observed at resting gastric pressure and volume. Gastric distension induced an increased frequency of venting episodes. In 13 (76%) animals the sphincter to yield was the cardia and in 4 (24%) the pylorns. The intragastric yield pressure is shown in the Table. The median venting volume was 33 -+38 ml per episode. Yield Sphincter Cardiac Pyloric p = .253 13vs. "/
n Yield Pressure (mmHg) 13 14 -+ 6.513 4 16 + 7.3"/ Median _+Interquartile Range
Conelusion: A non-yielding pyloric sphincter encourages incompetency at the cardia sphincter during gastric distension. This mechanism may be involved in the pathogenesis of postprandial gastroesophageal reflux. S0156 ACCUMULATION OF PItOSPHATIDYLCttOLINE HYDOPEROXIDE IN TIlE INTF~TINAL MUCOSA OF RATS ISCHEMIA / REPERFUSION MODEL. T.Masuko, I.Sasaki, Y.Funayama, H.Naito, K.Fukushima, C.Shibata, S.Matsuno, T.Miyazawa. First Department of Surgery, School of Medicine, Applied Biochemistry, School of Agliculture, Tohoku University, Sendal, Japan.
Background and Aim: Thiobarbituric acid reactant (TBARS) has been used as a popular method for estimating the oxidized lipids. But this assay is neither specific for the hydroperoxy group nor stoichiometric. The detection of a specific product of lipid peroxidatinn in ischemia/reperfusion injury in intestinal mucosa has not been estimated. Chemiluminescence detection-high performance liquid chromatography (CL-HPLC) is a system established in our labolatories to quantify a specific primary lipid product of the peroxidation. The aim of this study is to evaluate phosphatidylcholine hydropernxide (PCOOH), in comparison with TBARS in rat intestinal ischemia / reperfusion model. Methods: Under pentnbarbital anesthesia, six male Sprague-Dawley rats (200 to 240g) underwent 30 minutes of occlusive small intestinal ischemia followed by 30 to 360 minutes of reperfusinn (I/R group). Other 6 rats underwent 30 minutes of ischemia without reperfusion (Isch group). Non ischemic bowel (6 rats) was harvested as a control. Mucnsa was scraped and stored at -g0°c. Grade of the mucnsal injury (GMI) was scored histologically using Hematnxirin-Ensin staining. Mucosal levels of PCOOH and TBARS were measured by CL-HPLC and Ohkawa's method, respectively. Results: GMI was more severe in I/R group compared with Isch group. There were no significant differece in TBARS levels between the three groups (Fig). PCOOH level increased in I/R group (30 rain), and there were no significant difference between control group and Isch group .Conclusion: PCOOH is accumulated in intestinal mucosa after the ischemia / reperfusion in rats. We believe that detection of PCOOH using CL-HPLC will shed light on the evaluation of lipid peroxidatinn in the intestinal mucosa.
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S0157 MACROSCOPIC APPEARANCE OF TUMOR AND PANCREATIC INVASION ARE USEFUL PREDICTORS OF SURVIVAL IN SURGICAL TREATMENT OF AMPULLARY CARCINOMA. G. Matsumoto 1.2, K. Arai 1, T. Tsuchiyal 1, R. Anzai l, M. Takahashi 1, S. Matsuno 2, and T. Yamazaki 1. Department of Surgery, Sendai City Medical Center I and First Department of Surgery, Tohoku University School of Medicine 2, Sendal, Japan. Aims: To determine what factors affected the prognosis in patients with ampullary carcinoma and to investigate the possibility of preoperative prediction of the long-term outcome in these patients. Patients and Methods: From 1983 to 1997, 36 patients with ampullary carcinoma underwent surgical resection in Sendai City Medical Center. Pancreatodundenectomy including pylorus-preserving procedure was performed in 35 patients and one patient underwent local resection of the ampulla of Vater. Pathological factors influencing the prognosis were evaluated retrospectively. Results: Overall 5-year survival rate was 66.6%. Histnpathological factors favorably influencing the survival were negative lymph node metastasis (p < 0.0001), no pancreatic invasion (p < 0.01), and no duodenal invasion (p < 0.05). Tumor differentiation did not affect the prognosis. When patients were classified into the two groups depending on macroscopic appearances of tumor whether ulceration was observed or not, prognosis of the patients of non-ulceration type was significantly better than that of ulceration type
(5-year survival: 93.3% vs. 10.9%, p < 0.0001). In addition, all of the 17 patients with non-ulceration type tumor and no pancreatic invasion had no lymph node metastasis at operation and postoperative recurrence was not observed in these patients. Conclusion: Lymph node status is an important prognostic factor but difficult to be diagnosed preoperatively. Our study showed that macroscopic appearance of tumor and pancreatic invasion were correlated with the survival rate, which could be evaluated by endoscopy and endoscopic ultrasonography. These suggest that preoperative evaluation of macroscopic appearance of tumor and pancreatic invasion is useful for prediction of survival in patients with ampullary carcinoma. • S0158 CHARACTERIZATION AND REDUCTION OF ISCHEMIAJ REPERFUSION-INJURY AFTER EXPERIMENTAL PANCREAS TRANSPLANTATION. H. Mayer, J. Schmidt, J. Thies, E. Ryscbich, M.M. Gebhard*, Ch. Herfarth, E. Klar; Department of Surgery and *Department of Experimental Surgery, University of Heidelberg, Germany. Reperfusion injury after pancreas transplantation with subsequent disturbance of microcirculation is a common cause of early graft pancreatitis. The aim of this study was to quantify the pancreatic microcirculation after pancreas transplantation in correlation to cold ischemia time. In the second step the effect of N-Acetylcysteine (NAC) was tested in the impaired microcirculation. Methods: In male Lewis rats we performed pancreas transplantation according to the technique of Lee in three different groups. Group 1 and 2 received no special treatment. Cold ischemia time was 1.5 (group 1) and 16 hours (group 2+3). In group 3, donor and recipient were treated with NAC (300 mg/kilogram body weight). In all three groups the grafts were perfused and stored in UW-solution. In group 1 and 2 grafts were rinsed with saline solution, grafts of group 3 were rinsed with a saline solution containing 3mg/ml NAC before implantation. 1.5 hours after reperfusion graft microcirculation was quantified by means of intravital microscopy. Rhodamine-labeled leucocytes, FITC-labeled erythrocytes and FITC-labeled albumin were used as fluorochromes. Results: After a cold ischemia time of 16 hours functional capillary density (FCD) was reduced to 106 - 44 cm/cm2 compared to 155-+ 28 cm/cm2 after cold ischemia of 1.5 hours (p<0.05). Treatment with NAC led to a FCD of 149 -+ 18 cm/cm2 (p=0.05 compared with 16 hours without treatment). Erythrocyte velocity was 0.83 -+ 0.12 mm/s (1.5 hours); 0.52 _+0.13 (16 hours) and 0.66 + 0.12 (16 hours +NAC; p<0.05 NAC vs. control 16 hours). Leucocyte-endothelium interaction was also significantly aggravated after 16 hours ischemia time vs. 1.5 hours (10.8 vs. 7.1 Rollers/100ktm venule). NAC reduced teucocyte-endothelium-interaction to 7.0 Rollers/1001am venule (p<0.05). Conclusions: lschemia-/ Reperfusion injury after experimental pancreas transplantation is characterized by a disturbance of pancreatic microcirculation exhibiting a correlation to the duration of cold ischemia time. Erythrocyte velocity and functional capillary density were reduced, leucocyte-endothelium interaction was enhanced after a cold ischemia time of 16 hours compared to 1.5 hours. Treatment of donor and recipient with NAC resulted in a stabilisation of capillary perfusion. The clinical relevance of NAC in the reduction of ischemia/ reperfusion injury after pancreas transplantation remains to be investigated. S0159 RESULTS OF LAPAROSCOPIC NISSEN FUNDOPLICATION IN A TEACHING INSTITUTION. W. Scott Melvin. Ziad E. Abouezzi, William J. Schirmer and E. Christopher Ellison. Department of Surgery, The Ohio State University, Columbus, Ohio. We have been concerned that the change from open surgery to laparoscopy for advanced gastrointestinal surgery have a deleterious effect on the training of our residents. We specifically evaluated the exposure of our senior residents in the performance of antireflux procedures over the period over which this change has occurred. We analyzed our database on patients who underwent laparoscopic antireflux surgery from Jan. 1994 till Sept. 1997. Data on patients' age, operative time, intraoperative and postoperative complications, conversion rate, length of stay and readmission rate were analyzed. Case logs of graduating chief residents were also reviewed. One hundred-fifteen patients were included in the study with a mean age of 43 years (range from 19 to 73), all requiring medical treatment with an average duration of symptoms of 68 months. There were 106 Nissen, 6 Toupet and 3 Rosetti fundoplications. Only the first 20 were performed by two attending surgeons, after that residents were involved. Operating time averaged 196 min, there were no intraoperative complications. Conversion rate was 5.2% (6 patients). Mean length of stay was 2.1 days. 16 minor complications occurred (fever 6, respiratory 4, prolonged ileus 3, urinary 2, cardiac 2 and headache 1). There were 8 persistent dysphagia, 10 readmissions (8.6%) for poor oral intake 8, pneumonia 1 and foreign body impaction 1, and 3 reoperations. Over the same period of time, the total number of antireflux procedures done by a graduating chief resident up to the PGY5 level remained basically the same (mean total of 13.2) with 28.5% decrease (mean of 10.5 to 7.5) of open procedures and 111% increase of laparoscopic procedures (mean of 2.7 to 5.7). CONCLUSION: Laparoscopic antireflux procedures can be safely performed in an academic center. The advent of advanced laparoscopy did not decrease . the operative experience of surgical trainees in the field of antireflux procedures.