Joseph A. Trunzo

Natural Orifice Proctectomy Using a Transanal Endoscopic Microsurgical Technique in a Porcine Model

Background. Transanal endoscopic microsurgery (TEM) has been used for several decades for excision of neoplastic lesions in the rectum. With the development of natural orifice translumenal endoscopic surgery (NOTES) techniques, the authors describe a new method of proctectomy using a combination of TEM and NOTES principles. Methods. In a porcine model, a circumferential rectal sleeve resection was performed using TEM with flexible endoscopic assistance. The rectum was delivered through the anus, resected, and an end-to-end stapled anastomosis was performed. Results. The specimen was approximately 10 cm in length. No adjacent organ injuries or evidence of hemorrhage from the vascular pedicle or in the pelvis was observed at necropsy. Procedure time was 3 hours. Conclusion. This technique may increase the complexity of lesions accessible by TEM and may ultimately lead to the performance of total mesorectal excision using transanal techniques, reducing the morbidity of the abdominal approach.

Effect of parathyroidectomy on anemia and erythropoietin dosing in end-stage renal disease patients with hyperparathyroidism.

BACKGROUND It has been suggested that parathyroidectomy for hyperparathyroidism (HPT) in end-stage renal disease (ESRD) may result in improvement in anemia and the response to erythropoiesis-stimulating drugs. This study examines the effect parathyroidectomy had on erythropoietin (EPO) dosing requirements and anemia in ESRD. METHODS A retrospective review was conducted. Patients were included if pre-operative and 12 month postoperative hemoglobin (Hg) and hematocrit (Hct) levels were available and they did not receive a kidney transplant or have failure of parathyroidectomy during the follow-up. Erythropoietin (EPO) dose and serum levels of calcium, phosphorus, alkaline phosphatase, albumin, and parathyroid hormone (PTH) were also obtained. Other data collections were at 1 and 2 mos. postoperatively. RESULTS Thirty-seven patients met inclusion criteria. Parathyroidectomy resulted in decreased PTH from 1,871 +/- 236 (mean +/- SEM) to 172 +/- 29 pg/mL (P < .001) at 1 year. EPO dosing requirement showed a profound decrease from 10,086 +/- 1,721 to 3,514 +/- 620 units/week (P < .05). Hb and Hct levels followed an upward trend at 12 mos (11.4 +/- 0.3 to 12.1 +/- 0.2 g/dL and 35.7 +/- 1.0 to 37.1 +/- 0.6%, respectively). CONCLUSION In ESRD, parathyroidectomy for HPT improves anemia and decreases requirements for exogenous erythropoietin suggesting either increased endogenous EPO production or improved response. As a result, we propose refractory ESRD-associated anemia as a secondary indication for parathyroidectomy resection in this population.

Transgastric natural-orifice transluminal endoscopic surgery peritoneoscopy in humans: A pilot study in efficacy and gastrotomy site selection by using a hybrid technique

BACKGROUND Diagnostic natural-orifice transluminal endoscopic surgery (NOTES) peritoneoscopy can easily be performed with standard endoscopic equipment in animal studies. The efficacy and optimal transgastric site for NOTES access in humans, however, has not been determined. OBJECTIVE To characterize the efficacy of various anterior gastric access locations for diagnostic transgastric NOTES peritoneoscopy in humans. DESIGN Prospective clinical study. SETTING Tertiary-care center with experience in NOTES peritoneoscopy. PATIENTS Patients undergoing planned laparoscopic gastrectomy or gastrotomy involving the anterior aspect of the stomach were eligible. INTERVENTIONS An anterior gastric site for NOTES gastrotomy was chosen and transgastric NOTES access was independently established after laparoscopic abdominal exploration. Peritoneoscopy was then performed. The site of gastrotomy was closed as part of the intended laparoscopic procedure. MAIN OUTCOME MEASURES The ability to visualize the abdominal and pelvic organs in all four quadrants was determined. Patients were evaluated postoperatively for complications. RESULTS Eight patients requiring 9 procedures were studied. Gastrotomy sites were classified as body (n = 3), lesser curvature (n = 3), greater curvature (n = 1), fundus (n = 1), and antrum (n = 1). Satisfactory navigation could only be performed to the right upper and both lower quadrants. The left upper quadrant, specifically the spleen, was adequately visualized in only 1 case (11%), where the gastrotomy site was at the greater curvature. One patient developed a surgical site infection requiring oral antibiotic therapy. The median postoperative stay was 2 days (range, 0-3 days). LIMITATIONS Small number of patients. CONCLUSION NOTES peritoneoscopy with a gastrotomy on the anterior stomach permits adequate visualization of organs in the right upper and both lower quadrants. Visualization of the left upper quadrant and spleen is, however, limited unless access is gained on the greater curvature of the stomach. The accuracy of NOTES in identifying intra-abdominal pathology compared with laparoscopy remains to be determined.

Intraperitoneal Virtual Biopsy by Fibered Optical Coherence Tomography (OCT) at Natural Orifice Transluminal Endoscopic Surgery (NOTES)

IntroductionFibered optical coherence tomography (OCT) in conjunction with natural orifice transluminal endoscopic surgery (NOTES) could provide a facility for rapid, in situ pathological diagnosis of intraperitoneal tissues in a truly minimally invasive fashion.Materials and MethodsA large porcine model was established to test this hypothesis. A standard double channel gastroscope (Olympus) was used to achieve a transgastric access to the peritoneum and initiate the pneumoperitoneum. Magnetic retraction was used to display the sigmoid colon along with its mesentery. A commercially available fibered OCT probe (NIRIS system, Imalux) was inserted via a working channel of the gastroscope and used to assess intraperitoneal tissues. Separately, OCT images of human tissue specimens ex vivo were contrasted with representative standard histopathological slides.ResultsIntraperitoneal OCT provided clear real-time images of both the serosal and muscularis propria mural layers as well as the submuscosal–muscularis interface. Examination of mesenteric lymph nodes (including sentinel nodes) allowed visualization of their subcapsular sinus. Comparison of representative cross-sections however failed to evince sufficient resolution for confident diagnosis.ConclusionThis approach is technically feasible and, if the technology is advanced and proven accurate in human patients, could potentially be used to individualize operative extent prior to definitive resection.

Facilitating gastrotomy closure during natural-orifice transluminal endoscopic surgery using tissue anchors

BACKGROUND AND STUDY AIMS Reliable and secure closure of the gastrotomy after natural-orifice transluminal endoscopic surgery (NOTES) remains a critical step for widespread acceptance and use of this mode of surgery. We describe a novel method for gastrotomy closure using endoscopic tissue anchors. METHODS A standard upper endoscopy and wire placement as used for percutaneous endoscopic gastrostomy placement was performed in five pigs. Prior to gastrotomy, four tissue anchors were placed in four quadrants (1 cm away from the wire). A 12-mm gastrotomy was created endoscopically using a combination of needle-knife and balloon dilation. After transgastric peritoneoscopy, the sutures were approximated using a device knotting element. One additional pair of sutures was placed after evaluation of the gastric closure. The animals underwent in vivo contrast fluoroscopy, methylene blue instillation, and bursting pressure studies for assessment of the closure site. RESULTS All animals studied showed complete sealing of the gastrotomy site without evidence of leak on fluoroscopic imaging or at final postmortem intragastric methylene blue instillation. Improved insufflation ability following gastrotomy was also noted using this technique, which enhanced overall visualization during the closure. CONCLUSION Positioning tissue anchors prior to creating a NOTES gastrotomy was a feasible and reliable method to perform gastric closure. Follow-up survival studies will be warranted to support these preliminary findings.

Endoscopic full-thickness resection of gastric tumors using a novel grasp-and-snare technique: feasibility in ex vivo and in vivo porcine models

BACKGROUND AND STUDY AIMS Endoscopic full-thickness resection (EFTR) is a less-invasive method of en bloc removal of gastrointestinal tract tumors. The aim of this study was to evaluate the feasibility of a grasp-and-snare EFTR technique using a novel tissue-lifting device that provides more secure tissue anchoring and manipulation. METHODS EFTR of normal gastric tissue and model stomach tumors was performed using a double-channel therapeutic endoscope with a prototype tissue-lifting device through one channel and a prototype hexagonal snare through the other. The lifting device was advanced through the open snare and anchored to the gastric wall immediately adjacent the model tumor. The tissue-lifting device was then partially retracted into the endoscope, causing the target tissue, including tumor, to evert into the gastric lumen. The open snare was then placed distal to the tumor around uninvolved gastric tissue. Resection was performed with a blended electrosurgical current through the snare. In the live pigs, EFTR was followed by laparotomy to asses for complications. RESULTS 24 EFTRs were performed -- 14 in explanted stomachs and 10 in live pigs. In total, 23/24 resections resulted in full-thickness gastric defects. Resection specimens measured up to 5.0 cm when stretched and pinned on a histology stage. Gross margins were negative in 17/20 model tumor resections. Two resections were complicated by gastric mural bleeding. There was no evidence of adjacent organ injury. CONCLUSIONS EFTR of gastric tumors using the grasp-and-snare technique is feasible in pigs. This technique is advantageous in that eversion of the gastric wall avoids injury to external organs, continuous luminal insufflation is not required, and the involved techniques are familiar to endoscopists. Additional research is necessary to further evaluate safety and reliable closure.

Initial evaluation of a novel, prototype, forward-viewing echoendoscope in a porcine arterial bleeding model (with video)

BACKGROUND Real-time visualization of submucosal arterial flow at the base of an ulcer might improve endoscopic hemostasis by permitting more accurate assessment of the artery, precise targeting of therapy, and confirmation of vessel ablation. OBJECTIVE To evaluate the utility of a novel, forward-viewing echoendoscope in identifying bleeding submucosal arteries, guiding hemostatic therapy, and confirming cessation of flow through treated vessels. DESIGN In 7 pigs, a previously described porcine model for peptic ulcer hemorrhage was created by isolating the gastroepiploic and/or short gastric artery and tunneling it into the subserosal space at laparotomy. SETTING Animal research facility. INTERVENTION The prototype endoscope was used to image submucosal arterial flow. EUS guidance was then used to deliver endoscopic hemostatic therapy and assess treatment adequacy. MAIN OUTCOME MEASUREMENTS Identification of the target submucosal artery and successful delivery of EUS-guided endoscopic therapy, evidenced by cessation of Doppler flow through the target vessel. RESULTS Tunneled arteries were visualized endosonographically in all 7 cases. EUS-guided submucosal injection of epinephrine was successful in 2 of 2 cases. EUS-guided delivery of thermal hemostatic therapy was successful in 2 of 4 cases. Absence of flow through treated vessels was confirmed in cases in which EUS-guided therapy was successfully delivered. LIMITATIONS Acute animal model. CONCLUSION Proof of principle experiments in a porcine peptic ulcer hemorrhage model suggest that real-time sonographic imaging of submucosal arteries is feasible with a forward-viewing echoendoscope, and guided hemostatic therapy can be delivered.

Endoscopic full-thickness resection of gastric lesions using a novel grasp-and-snare technique: evaluation in a porcine survival model

BackgroundEndoscopic full-thickness resection (EFTR) is a less-invasive method of en bloc removal of gastrointestinal tumors. In a previous nonsurvival animal experiment, the feasibility of a novel grasp-and-snare EFTR technique using a prototype tissue-lifting device was demonstrated. The objective of this study was to evaluate the safety and outcomes of this EFTR method in a porcine survival model.MethodsEFTR of model stomach tumors was performed in seven pigs using a double-channel endoscope with a prototype tissue-lifting device through one channel and snare through the other. The lifting device was advanced through the snare loop and anchored to the gastric wall adjacent the model tumor. The lifting device was then partially retracted into the endoscope, causing the target tissue, including tumor, to evert into the gastric lumen. The open snare was then placed beyond the tumor around uninvolved gastric tissue. Resection was performed by delivering an electrosurgical current through the snare. EFTR defects were closed by using tissue anchors. After an intended 10-day observation period, the pigs were euthanized and necropsy was performed.ResultsAll seven resections were successful with negative gross margins. No immediate complications occurred. Two defect closures failed during the early postoperative period, leading to infectious complications. The remaining intact closures were complicated by adjacent ulcers, one of which resulted in hemorrhage.ConclusionsEndoscopic full-thickness resection of gastric lesions using the grasp-and-snare technique is feasible in pigs. In this experiment, complications related to closure were significant. Further evaluation and modification of closure technique is necessary before studying this method of EFTR in humans.

Hydroperitoneum-facilitated EUS-guided peritoneal entry and closure of alternate access sites for NOTES.

Background: Access sites other than the anterior gastric wall may provide improved ergonomics for natural orifice transluminal endoscopic surgery (NOTES). Endoscopic ultrasound (EUS) guidance significantly reduces, but does not eliminate, risk of access through these alternate sites. This study evaluates the utility of hydroperitoneum as an adjunct to EUS-guided access and closure of alternate access sites for NOTES. Methods: Access and closure procedures were initially performed with EUS guidance alone, and subsequently, because of complications resulting from this technique, the procedures were performed with the aid of a transabdominal hydroperitoneum. Results: In this nonrandomized study, 6 access and closure procedures performed with EUS guidance alone resulted in 4 complications. After modifying the technique to incorporate pre-access hydroperitoneum, 7 EUS-guided access and closure procedures were performed without significant complications. Conclusions: Hydroperitoneum appears to be an effective adjunct to ensure the safety of EUS-guided peritoneal entry and closure of alternate access sites for NOTES.

Comparison of anterior transgastric access techniques for natural orifice translumenal endoscopic surgery

BackgroundThe advancement of natural orifice translumenal endoscopic surgery (NOTES) into clinical practice is dependent on its safety, efficacy, and efficiency. Access is the obligatory first step in NOTES and serves as a surrogate to technical difficulties associated with this novel surgical approach. This study aimed to compare endoscopic transgastric access techniques in terms of safety, reproducibility, and efficiency.MethodsSeven variations for anterior transgastric NOTES access were evaluated with female domestic swine. After marking of an anterior site, electrocautery was used to create a small gastrotomy, followed by balloon dilation and entry into the peritoneal cavity. Methodologic variations incorporated the use of guidewires, electrocautery and dilation combined within a single device, support tubes, and dilation without electrocautery. Access times were recorded, and tissue injury was evaluated.ResultsIn 70 access attempts, the most serious complication was bleeding from the gastroepiploic vessel, controlled with electrocautery. High variability in access times was prevalent with almost all the access techniques.ConclusionsThis study supports the presumption that an anterior transgastric access technique for NOTES procedures is safe. The use of a wire to mark the site and another wire to retain the gastrotomy provided safe, efficient, and reproducible transgastric access. Comparison with laparoscopy exposed the disparity in technical challenges facing NOTES, suggesting that new technology and further refinement in methodology are required for NOTES to be clinically relevant.