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Michael R Marohn

Publications and source records attributed to Michael R Marohn.

11 recordsLinked to original sources
PubMed2006

CO2 abdominal insufflation pretreatment increases survival after a lipopolysaccharide-contaminated laparotomy.

Carbon dioxide (CO(2))-pneumoperitoneum is known to favorably modify the systemic immune response during laparoscopic surgery. The presented studies were designed to determine whether treating animals with CO(2) abdominal insufflation before undergoing a lipopolysaccharide (LPS)-contaminated laparotomy would serve as "shock prophylaxis" and thus improve survival and attenuate cytokine production. Rats were randomized into five groups: CO(2)-pneumoperitoneum, helium-pneumoperitoneum, anesthesia control, laparotomy/LPS control, and LPS only control. Animals in the first four groups all received a laparotomy and a lethal dose of LPS. Immediately preceding their laparotomy, animals in the pneumoperitoneum groups received a 30-minute pretreatment of abdominal insufflation with either CO(2) or helium. The anesthesia control group received a 30-minute pretreatment of isoflurane. Animal mortality was then recorded during the ensuing 72 hours. Subsequently, a similar protocol was repeated for measurements of cytokines. CO(2)-pneumoperitoneum increased survival at 48 hours compared with LPS control (P <.05), and decreased interleukin-6 plasma levels at 2 hours (P <.05). Abdominal insufflation with CO(2) before the performance of a laparotomy contaminated with endotoxin increases survival and attenuates interleukin-6. The beneficial immune-modulating effects of CO(2)-pneumoperitoneum endure after abdominal insufflation. CO(2)-pneumoperitoneum pretreatment may improve outcomes among patients undergoing gastrointestinal surgery who are at high risk for abdominal fecal contamination.

Anesthesia, Inhalation↗
PubMed2006

Does pancreatic duct stenting decrease the rate of pancreatic fistula following pancreaticoduodenectomy? Results of a prospective randomized trial.

Pancreatic duct stenting remains an attractive strategy to reduce the incidence of pancreatic fistulas following pancreaticoduodenectomy (PD) with encouraging results in both retrospective and prospective studies. We performed a prospective randomized trial to test the hypothesis that internal pancreatic duct stenting reduces the development of pancreatic fistulas following PD. Two hundred thirty-eight patients were randomized to either receive a pancreatic stent (S) or no stent (NS), and stratified according to the texture of the pancreatic remnant (soft/normal versus hard). Four patients were excluded from the study; in three instances due to a pancreatic duct that was too small to cannulate and in the other instance because a total pancreatectomy was performed. Patients who randomized to the S group had a 6-cm-long segment of a plastic pediatric feeding tube used to stent the pancreaticojejunostomy anastomosis. In patients with a soft pancreas, 57 randomized to the S group and 56 randomized to the NS group. In patients with a hard pancreas, 58 randomized to the S group and 63 randomized to the NS group. The S and NS groups for the entire study population, as well as for the subgroup of high-risk patients with soft pancreata, were similar as regard to demographics, past medical history, preoperative symptoms, preoperative procedures, and intraoperative data. The pancreatic fistula rate for the entire study population was 9.4%. The fistula rates in the S and NS subgroups with hard pancreata were similar, at 1.7% and 4.8% (P = 0.4), respectively. The fistula rates in the S and NS subgroups with soft pancreata were also similar, at 21.1% and 10.7% (P = 0.1), respectively. A nonstatistically significant increase in the pancreatic fistula rate in the S group persisted after adjusting for the operating surgeon and technical details of the operation (e.g., anastomotic technique, anastomotic orientation, pancreatic duct size, and number of intra-abdominal drains placed). In patients with soft pancreata, 63% percent of the pancreatic fistulas in stented patients required adjustment to the clinical pathway (including two deaths), compared to 47% of the pancreatic fistulas in patients in the NS group (P = 0.3). Internal pancreatic duct stenting does not decrease the frequency or the severity of postoperative pancreatic fistulas.

Adult↗
PubMed2006

Mentoring console improves collaboration and teaching in surgical robotics.

BACKGROUND: One of the most significant limitations of surgical robots has been their inability to allow multiple surgeons and surgeons-in-training to engage in collaborative control of robotic surgical instruments. We report the initial experience with a novel two-headed da Vinci surgical robot that has two collaborative modes: the "swap" mode allows two surgeons to simultaneously operate and actively swap control of the robot's four arms, and the "nudge" mode allows them to share control of two of the robot's arms. MATERIALS AND METHODS: The utility of the mentoring console operating in its two collaborative modes was evaluated through a combination of dry laboratory exercises and animal laboratory surgery. The results from surgeon-resident collaborative performance of complex three-handed surgical tasks were compared to results from single-surgeon and single-resident performance. Statistical significance was determined using Student's t-test. RESULTS: Collaborative surgeon-resident swap control reduced the time to completion of complex three-handed surgical tasks by 25% compared to single-surgeon operation of a four-armed da Vinci (P < 0.01) and by 34% compared to single-resident operation (P < 0.001). While swap mode was found to be most helpful during parts of surgical procedures that require multiple hands (such as isolation and division of vessels), nudge mode was particularly useful for guiding a resident's hands during crucially precise steps of an operation (such as proper placement of stitches). CONCLUSION: The da Vinci mentoring console greatly facilitates surgeon collaboration during robotic surgery and improves the performance of complex surgical tasks. The mentoring console has the potential to improve resident participation in surgical robotics cases, enhance resident education in surgical training programs engaged in surgical robotics, and improve patient safety during robotic surgery.

Animals↗
PubMed2006

Laparoscopic resection of a paraganglioma of the organ of Zuckerkandl in a patient with a carotid body tumor.

Paragangliomas of the organ of Zuckerkandl are rare tumors with only several case reports noted in the literature. Synchronous paraganglioma occur sporadically, and on occasion, in association with several genetic syndromes. Paraganglioma of the organ of Zuckerkandl with synchronous carotid body paraganglioma is described herein. Traditionally, surgical resection of abdominal paraganglioma involved an exploratory laparotomy. In this manuscript, we describe one of the first reported laparoscopic resections of this tumor and review the literature on multiple paragangliomas and their associated genetic syndromes.

Adult↗
PubMed2005

Abdominal insufflation with CO2 causes peritoneal acidosis independent of systemic pH.

We have shown that the inflammation-attenuating effects of CO(2) pneumoperitoneum during laparoscopy are not due to changes in systemic pH. However, acidification of peritoneal macrophages in an in vitro CO(2) environment has been shown to reduce LPS-mediated cytokine release. We tested the hypothesis that the peritoneum is locally acidotic during abdominal insufflation with CO(2)--even when systemic pH is corrected. Rats (n = 20) were anesthetized and randomized into two groups: continued spontaneous ventilation (SV) or intubation and mechanical ventilation (MV). All animals were then subjected to abdominal insufflation with CO(2). Mean arterial pH among SV rats decreased significantly from baseline after 15 and 30 minutes of CO(2) pneumoperitoneum (7.329 --> 7.210 --> 7.191, P < 0.05), while arterial pH among MV rats remained relatively constant (7.388 --> 7.245 --> 7.316, P = NS). In contrast, peritoneal pH dropped significantly from baseline and remained low for both groups during CO(2) abdominal insufflation (SV 6.74 --> 6.41 --> 6.40, P < 0.05; MV 6.94 --> 6.45 --> 6.45, P < 0.05). In a second experiment, rats (n = 10) were randomized to receive abdominal insufflation with either CO(2) or helium. Abdominal insufflation with helium did not significantly affect peritoneal pH (7.10 --> 7.02 --> 6.95, P = NS), and the decrease in pH among CO(2)-insufflated animals was significant compared with helium-insufflated animals (P < 0.05). Peritoneal pH returned to baseline levels in all groups within 15 minutes of desufflation in both experiments. A significant local peritoneal acidosis occurs during laparoscopy which is specifically attributable to the use of CO(2) and which is independent of systemic pH. These data provide additional evidence that localized peritoneal acidosis is central to the mechanism of CO(2)-mediated attenuation of the inflammatory response following laparoscopic surgery.

Acidosis↗
PubMed2005

Carbon dioxide pneumoperitoneum-mediated attenuation of the inflammatory response is independent of systemic acidosis.

BACKGROUND: The purpose of this study was to determine if systemic acidosis induced by peritoneal absorption of carbon dioxide (CO2 ) during laparoscopy plays a role in CO2 pneumoperitoneum-mediated attenuation of the acute phase inflammatory response associated with perioperative sepsis. The influence of hepatic polymorphonuclear (PMN) leukocyte infiltration on this phenomenon was also investigated. METHODS: Forty-five rats were randomized into 5 groups: anesthesia control, open cecal ligation and puncture (OCLP), laparoscopic cecal ligation and puncture using helium for insufflation (He LCLP), LCLP using CO2 with continued spontaneous ventilation (LCLP-SV), and LCLP using CO2 with intubation and positive pressure ventilation (LCLP-PPV). RESULTS: After 30 minutes, arterial blood gas parameters remained normal in control, OCLP rats, and He LCLP rats, while CO2 LCLP-SV rats developed significant hypercarbic acidosis. This acidosis was corrected in CO2 LCLP-PPV rats ( P < .0001 vs CO2 LCLP-SV for both). Expression of the rat acute phase gene alpha 2 -macroglobulin was greater after OCLP and He LCLP than after either CO2 LCLP-SV or CO2 LCLP-PPV ( P < .0001 vs either CO2 OCLP-SV for both). However, levels of alpha 2 -macroglobulin were not significantly different between the acidotic (LCLP-SV) and normocarbic (LCLP-PPV) CO2 groups. Infiltration of the hepatic parenchyma by PMNs did not differ significantly between groups. CONCLUSIONS: CO2 insufflation-induced systemic acidosis is not responsible for the reduction in the acute phase inflammatory response observed in laparoscopic animal models of sepsis. Hepatic PMN infiltration also does not appear to mediate this effect.

Acidosis↗
PubMed2004

Multiservice laparoscopic surgical training using the daVinci surgical system.

BACKGROUND: The daVinci surgical system affords surgeons a magnified three-dimensional videoscopic view of the operative field and precise articulating laparoscopic instruments. The learning curve for this advanced surgical robotics system is poorly characterized. METHODS: Twenty-three surgeons representing seven surgical subspecialties participated in a surgical robotics training program consisting of standardized daVinci system training (phase 1) followed by self-guided learning in a porcine model (phase 2). RESULTS: The average number of recorded procedures performed per surgeon during phase 2 was 5.5. The mean daVinci system set-up time was 45 minutes and decreased by an average of 56.1% by the third successive set-up (r = -0.702, P <0.005). Operative times decreased 39.0% by the third successive practice operation (r = -0.860, P <0.0005). CONCLUSIONS: New use of the daVinci robot is associated with a rapid learning curve and preclinical animal model training is effective in developing surgical robotics skills.

Animals↗
PubMed2004

Videoendoscopic endotracheal intubation in the rat: a comprehensive rodent model of laparoscopic surgery.

BACKGROUND: Peritoneal absorption of CO(2) during abdominal insufflation in laparoscopy may disrupt the acid-base equilibrium and alter the physiological response to stress. Current nonventilated rodent models of laparoscopy do not manage the CO(2) load of pneumoperitoneum, but ventilated surgical rodent models are invasive (tracheotomy) and may independently induce the inflammatory response. MATERIALS AND METHODS: A comprehensive rodent model of laparoscopy was developed. Rats were randomized to receive anesthesia alone, anesthesia plus CO(2) pneumoperitoneum, or anesthesia plus CO(2) pneumoperitoneum with videoendoscopic intubation and mechanical ventilation. Arterial blood-gas analysis was performed at baseline and after 30 min of intervention. RESULTS: Baseline pH, pCO(2), and HCO(3)(-) arterial blood gas parameters were normal for all rats. After 30 min, pCO(2) and pH changed slightly but remained normal among rats receiving anesthesia alone (pCO(2) = 46.5 +/- 1.9; pH = 7.365 +/- 0.009) whereas animals receiving anesthesia plus CO(2) pneumoperitoneum that were dependent on spontaneous respiration for ventilation developed significant hypercarbic acidosis (pCO(2) = 53.2 +/- 1.9, P < 0.05; pH = 7.299 +/- 0.011, P < 0.001). This acidosis was completely corrected with increased minute ventilation in intubated rats receiving mechanical ventilation (pCO(2) = 36.8 +/- 1.5, P < 0.001; pH = 7.398 +/- 0.011, P < 0.001). CONCLUSIONS: CO(2) pneumoperitoneum induces significant hypercarbic acidosis in nonventilated rats. Noninvasive endotracheal intubation is feasible in the rat with videoendoscopic assistance. Our noninvasive rodent model of laparoscopic surgery controls for anesthesia- and capnoperitoneum-related acid-base changes and provides an environment in which the biological response to pneumoperitoneum can be studied precisely.

Acid-Base Equilibrium↗
PubMedDate not supplied

Twenty-first century surgery using twenty-first century technology: surgical robotics.

INTRODUCTION: The "Nintendo" surgery revolution, which began in 1987, has impacted every surgical specialty. However, our operating rooms remain isolated worlds where surgeons use awkward, primitive, rigid instruments with suboptimal visualization. We need "smart instruments," "smart technology," and "smart imaging." Is surgical robotics the answer? METHODS: We provide an analysis of current surgical technology and skills, propose criteria for what the next generation of surgical instruments and technology should achieve, and then examine the evolution and current state of surgical robotic solutions, assessing how they answer future surgical needs. Finally we report on the U.S. Military's early experience with surgical robotics and the lessons learned therein. RESULTS: Current surgical robotic technology has made remarkable progress with miniaturization, articulating hand-imitating instruments, precision, scaling, and three-dimensional vision. The specialty-specific early clinical applications reviewed are promising, but they do have limitations. Surgical robotics offers enormous military application potential. Needed future refinements are identified, including haptics, communications, infrastructure, and information integration. CONCLUSIONS: Laparoscopic surgery is a transition technology, constrained by instrument, equipment, and skill limitations. Surgical robotics or, more properly, computer-assisted surgery may be the key to the future. The operating room of the future will be an integrated environment with global reach. Surgeons will operate with three-dimensional vision, use real-time three-dimensional reconstructions of patient anatomy, use miniaturized minimally invasive robotic technology, and be able to telementor, teleconsult, and even telemanipulate at a distance, thus offering enhanced patient care and safety.

General Surgery↗
PubMedDate not supplied

Laparoscopic total abdominal colectomy in the acute setting.

We report results from a single surgeon's 10-year team experience with laparoscopic total abdominal colectomy. We review our series, which includes a large subgroup of ill, high-risk patients with acute colitis requiring urgent surgery. From 1993 to 2003, we performed 65 laparoscopic total abdominal colectomies. All patients referred for total abdominal colectomy were offered the laparoscopic approach. We prospectively collected the following data on all patients: demographics, surgical indications, preoperative status, duration of surgery, intraoperative blood loss, operative complications, length of stay, subsequent operations, patient satisfaction, and lessons learned from our team experience. Preoperative diagnoses included ulcerative colitis (n=55), Crohn's colitis (n=3), colonic inertia (n=4), and familial adenomatous polyposis (n=3). Among the patients with inflammatory bowel disease, 70% of cases were performed on ill patients, refractory to medical management, requiring urgent surgery. This subgroup was managed with laparoscopic total abdominal colectomy and Brooke ileostomy, with ileoanal pouch anastomosis deferred. Operative times were long, ranging from 6 to 11 hours. Mean intraoperative blood loss was 200 ml. Mean length of stay was 4.3 days and ranged from 2 to 13 days. There were no conversions to open surgery and there were no deaths. Complications occurred in 12% of patients and included intra-abdominal abscess (n=2), wound infection (n=3), stoma stenosis (n=1), and incisional hernia (n=2). Postoperative patient satisfaction was high. Subsequent operations, including restorative proctectomy, were also performed laparoscopically. Laparoscopic total abdominal colectomy is technically challenging and requires a team approach but offers patients significant benefit in length of stay and surgical recovery. This operation can be effectively used with minimal morbidity in difficult, ill patients requiring urgent surgery.

Abdominal Abscess↗