Garth H. Ballantyne

Robotic surgery, telerobotic surgery, telepresence, and telementoring

Although laparoscopic cholecystectomy rapidly became the standard of care for the surgical treatment of cholelithiasis, very few other abdominal or cardiac operations are currently performed using minimally invasive surgical techniques. The inherent limitations of traditional laparoscopic surgery make it difficult to perform these operations. We, and others, have attempted to use robotic technology to (a) provide a stable camera platform, (b) replace two-dimensional with three-dimensional (3-D) imaging, (c) simulate the fluid motions of a surgeons wrist to overcome the motion limitations of straight laparoscopic instruments, and (d) offer the surgeon a comfortable, ergonomically optimal operating position. In this article, we review the early published clinical experience with surgical robotic and telerobotic systems and assess their current limitations. The voice-controlled AESOP robot replaces the cameraperson and facilitates the performance of solo-surgeon laparoscopic operations. AESOP provides a stable camera platform and avoids motion sickness in the operative team. The telerobotic Zeus and da Vinci surgical systems permit solo surgery by a surgeon from a remote sight. These telerobots hold the camera, replace the surgeons two hands with robotic instruments, and serve in a master–slave relationship for the surgeon. Their robotic instruments simulate the motions of the surgeons wrist, facilitating dissection. Both telerobots use 3-D imaging to immerse the surgeon in a three-dimensional video operating field. These robots also provide operating positions for the surgeon console that are ergonomically superior to those required by traditional laparoscopy. The technological advances of these telerobots now permit telepresence surgery from remote locations, even locations thousands of miles away. In addition, telepresence permits the telementoring of novice surgeons who are performing new procedures by expert surgeons in remote locations. The studies reviewed here indicate that robotics and telerobotics offer potential solutions to the inherent problems of traditional laparoscopic surgery, as well as new possibilities for telesurgery and telementoring. Nonetheless, these technologies are still in an early stage of development, and each device entails its own set of challenges and limitations for actual use in clinical settings.

Volvulus of the colon. Incidence and mortality.

Between 1960 and 1980, 137 patients with colonic volvulus (52% cecal, 3% transverse colon, 2% splenic flexure, and 43% sigmoid) were seen at the Mayo Clinic. Among the 59 patients with sigmoid volvulus, four (7%) had colonic infarction. Total mortality with sigmoid volvulus was seven per cent. There were 71 patients with cecal volvulus. Colonoscopic decompression was accomplished in two of these patients; in 15 (21%), gangrenous colon developed and mortality was 33%. Total mortality for cecal volvulus patients was 17%. Mortality for all forms of volvulus in patients with viable colons was 11%. Mortality for all patients with volvulus was 14%.

Robotic-assisted laparoscopic low anterior resection with total mesorectal excision for rectal cancer

BackgroundWith advanced stereoscopic vision, lack of tremor, and the ability to rotate the instruments surgeons find that robotic systems are ideal laparoscopic tools. Because of its high operating cost, however, robotic surgery should be reserved to procedures in which the technology can be of maximum benefit, usually when precise dissections in confined spaces are required. Because conventional laparoscopic total mesorectal excision is a challenging procedure, we have sought to assess the utility of the DaVinci robotic system in laparoscopic low anterior resections for cancer of the rectum.MethodsBetween November 2004 and May 2005 robotic-assisted low anterior resection with total mesorectal excision was performed on six consecutive patients with rectal cancer. These cases were compared with six consecutive low anterior resections performed with conventional laparoscopic techniques by the same surgeon.ResultsThere were no conversions in either group. Operative and pathological data, complications, and hospital stay were similar in the two groups. Robotic operations appeared to cause less strain for the surgeon.ConclusionsRobotic-assisted laparoscopic low anterior resection for rectal cancer is feasible in experienced hands. This technique may facilitate minimally invasive radical rectal surgery.

The da Vinci telerobotic surgical system: the virtual operative field and telepresence surgery

The United States Department of Defense developed the telepresence surgery concept to meet battlefield demands. The da Vinci telerobotic surgery system evolved from these efforts. In this article, the authors describe the components of the da Vinci system and explain how the surgeon sits at a computer console, views a three-dimensional virtual operative field, and performs the operation by controlling robotic arms that hold the stereoscopic video telescope and surgical instruments that simulate hand motions with seven degrees of freedom. The three-dimensional imaging and handlike motions of the system facilitate advanced minimally invasive thoracic, cardiac, and abdominal procedures. da Vinci has recently released a second generation of telerobots with four arms and will continue to meet the evolving challenges of surgery.

Superior mesenteric artery syndrome. Diagnostic criteria and therapeutic approaches.

The hospital records and radiographs of 44 patients diagnosed as having superior mesenteric artery syndrome were reviewed using strict clinical and radiographic criteria. Only six (14.6 percent) of the patients fulfilled these criteria, suggesting over-diagnosis of the disorder. An acute change in clinical status, such as an operation or complication of a medical disease, appeared to precipitate the superior mesenteric artery syndrome in these patients, all of whom had chronic debilitating diseases. In four of the six patients conservative therapy failed, and they required surgical decompression.

Laparoscopic Roux-en-Y gastric bypass

Background: Increasing numbers of laparoscopic surgeons are performing laparoscopic Roux-en-Y gastric bypass (LGB). Our aim was to determine the length of the learning curve for a skilled laparoscopic surgeon. Methods: The study population consisted of the first 225 consecutive LGB procedures attempted by one laparoscopic surgeon (HJS). Outcome parameters included mortality, morbidity, operative time, and conversion to an open procedure. Results: Average operative time decreased from 189 min (first 75 patients) to 125 minutes (last 75 patients). Most of the improvement in operative time occurred over the first 75 patients. The perioperative complication rate decreased from 32% (first 75 patients) to 15% (second and third groups of 75 patients). Complication rates did not significantly decrease after the first 75 patients. Low mortality and conversion rates were achieved early in the series. Conclusion: Low mortality rates and low conversion rates can be achieved early in the learning curve for LGB. Complication rates plateau after approximately 75 LGBs, and operative times decrease substantially over the initial 75 cases. Operative times continue to decrease at a slower rate beyond 75 cases.

Changes in insulin resistance following bariatric surgery: Role of caloric restriction and weight loss

The prevalence of type 2 diabetes mellitus (T2DM) and obesity in the western world is steadily increasing. Bariatric surgery is an effective treatment of T2DM in obese patients. The mechanism by which weight loss surgery improves glucose metabolism and insulin resistance remains controversial. In this review, we propose that two mechanisms participate in the improvement of glucose metabolism and insulin resistance observed following weight loss and bariatric surgery: caloric restriction and weight loss. Nutrients modulate insulin secretion through the entero-insular axis. Fat mass participates in glucose metabolism through the release of adipocytokines. T2DM improves after restrictive and bypass procedures, and combinations of restrictive and bypass procedures in morbidly obese patients. Restrictive procedures decrease caloric and nutrient intake, decreasing the stimulation of the entero-insular axis. Gastric bypass (GBP) operations may also affect the entero-insular axis by diverting nutrients away from the proximal GI tract and delivering incompletely digested nutrients to the distal GI tract. GBP and biliopancreatic diversion combine both restrictive and bypass mechanisms. All procedures lead to weight loss and decrease in the fat mass. Decrease in fat mass significantly affects circulating levels of adipocytokines, which favorably impact insulin resistance. The data reviewed here suggest that all forms of weight loss surgery lead to caloric restriction, weight loss, decrease in fat mass and improvement in T2DM. This suggests that improvements in glucose metabolism and insulin resistance following bariatric surgery result in the short-term from decreased stimulation of the entero-insular axis by decreased caloric intake and in the long-term by decreased fat mass and resulting changes in release of adipocytokines. Observed changes in glucose metabolism and insulin resistance following bariatric surgery do not require the posit of novel regulatory mechanisms.

Peptide YY(1-36) and Peptide YY(3-36): Part I. Distribution, Release and Actions

Peptide YY (PYY) is a 36 amino acid, straight chain polypeptide, which is co-localized with GLP-1 in the L-type endocrine cells of the GI mucosa. PYY shares structural homology with neuropeptide Y (NPY) and pancreatic polypeptide (PP), and together form the Neuropeptide Y Family of Peptides, which is also called the Pancreatic Polypeptide-Fold Family of Peptides. PYY release is stimulated by intraluminal nutrients, including glucose, bile salts, lipids, shortchain fatty acids and amino acids. Regulatory peptides such as cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP), gastrin and GLP-1 modulate PYY release. The proximal GI tract may also participate in the regulation of PYY release through vagal fibers. After release, dipeptidyl peptidase IV (DPP-IV; CD 26) cleaves the N-terminal tyrosine-proline residues forming PYY(3-36). PYY(1-36) represents about 60% and PYY(3-36) 40% of circulating PYY. PYY acts through Y-receptor subtypes: Y1, Y2, Y4 and Y5 in humans. PYY(1-36) shows high affinity to all four receptors while PYY(3-36) is a specific Y2 agonist. PYY inhibits many GI functions, including gastric acid secretion, gastric emptying, small bowel and colonic chloride secretion, mouth to cecum transit time, pancreatic exocrine secretion and pancreatic insulin secretion. PYY also promotes postprandial naturesis and elevates systolic and diastolic blood pressure. PYY(1-36) and PYY(3-36) cross the blood-brain barrier and participate in appetite and weight control regulation. PYY(1-36) acting through Y1- and Y5-receptors increases appetite and stimulates weight gain. PYY(3-36) acting through Y2-receptors on NPY-containing cells in the arcuate nucleus inhibits NPY release and, thereby, decreases appetite and promotes weight loss. PYY may play a primary role in the appetite suppression and weight loss observed after bariatric operations.

Measuring Outcomes following Bariatric Surgery: Weight Loss Parameters, Improvement in Co-morbid Conditions, Change in Quality of Life and Patient Satisfaction

Restrictive and particularly malabsorptive bariatric operations achieve significant sustained weight loss. Results from different operations have been difficult to compare.The aims of this review are: 1) to indicate the limitations of outcomes reported as weight-related parameters; 2) to document some of the patient characteristics that impact weight loss; 3) to assess the literature documenting improvement in obesity-related medical conditions; and 4) to review studies that quantitate changes in health-related quality of life (QoL). Weight-related parameters such as body mass index and % excess weight inconsistently correlate with body fat. Direct determination of body fat with bioelectric impedance may offer more reliable outcome parameters. Patient characteristics such as gender, age, weight, body mass index, ethnicity, race and socioeconomic status affect weight loss following bariatric operations. Improvements in co-morbid conditions are poorly documented in many studies. Standardized instruments that assess health-related QoL have shown differing values. SF-36 has given inconsistent results following bariatric operations. Both BAROS and IWQoL-Lite have demonstrated significant improvements after surgery. Bariatric surgeons have rarely used patient satisfaction as an outcome parameter. This review suggests that bariatric operations should be judged by change in fat mass or fat mass index, improvement in obesity-related medical conditions, change in health-related QoL as judged by standardized instruments, and level of patient satisfaction. In addition, surgeons should characterize their study population and report outcomes for sub-populations.

Short-Term Results of Laparoscopic Gastric Bypass in Patients with BMI ≥60

Background: Laparoscopic Roux-en-Y gastric bypass (LRYGBP) has been shown to be safe and effective. Little information is available about the subgroup of patients with BMI ≥60. The goal of this study was to evaluate the feasibility and safety of LRYGBP for patients with BMI ≥60. Methods: The study consisted of the first 300 attempted LRYGBPs performed by one surgeon (HJS). This population was analyzed as 2 groups of patients: those with BMI <60 and those with BMI ≥60. Outcome variables included mortality, complications, conversion, and operative time. Results: Of the first 300 LRYGBP patients, 261 had BMI <60 and 39 had BMI ≥60. Age, comorbidity rate, and gender distribution were similar in both BMI groups. Conversion rates were <3% in both groups. Mean operative time for the BMI ≥ 60 group was 156 minutes vs 139 minutes in the lighter group (P=0.04). Major complications occurred more commonly in the BMI ≥60 group (10% vs 6%) but this difference was not significant. The types of complications differed between the 2 groups, with infectious complications and gastrointestinal leak occurring more frequently in the heavier group. The mortality rate was higher in the heavier group (5% vs 0.4%, P=0.055). Conclusion: LRYGBP is feasible for patients with BMI ≥60. Our data suggest that these patients are at a higher risk for GI leak, postoperative infection, and death.