Exploring the Efficacy of the Paula Method of Muscle Exercises in Managing Low Anterior Resection Syndrome Using an Integrative Approach: A Preliminary Study.

Background: Low anterior resection syndrome (LARS) is a post-proctectomy consequence characterized by variable and unpredictable bowel function, including clustering, urgency, and incontinence, which significantly impacts the quality of life. Currently, there is no established gold-standard therapy for LARS. Primary Study Objective: This study aimed to evaluate the effectiveness of the Paula method of exercise as part of an integrative treatment approach for patients with LARS. Design: This preliminary study utilized a single-arm pretest-posttest design. Setting: The study was conducted at a tertiary care medical center. Participants: Five patients diagnosed with LARS completed the study. Intervention: Participants underwent twelve weeks of individualized Paula method exercise sessions. Two questionnaires were employed to assess the severity of LARS and quality of life. Primary Outcome Measures: (1) Low Anterior Resection Syndrome (LARS) Score; (2) Memorial Sloan Kettering Cancer Bowel Function Instrument (MSK-BFI); (3) Global Quality-of-Life (QOLS) Score . Results: All participants completing the 12-week Paula exercise regimen reported no difficulty in engaging with the exercises. Statistically significant improvements were observed in both the LARS score and MSK-BFI (P = .039 and P = .043, respectively, Wilcoxon Rank Sum test). While there were improvements in the global quality-of-life score and functional scales of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, these improvements did not reach statistical significance. Conclusions: This preliminary study suggests that patients with LARS can successfully complete a 12-week exercise program using the Paula method, resulting in improved LARS scores. However, further investigation through larger, multicenter, randomized controlled trials is necessary to establish the efficacy of these exercises as a treatment for LARS.

Incidence and Risk Factors for Low Anterior Resection Syndrome following Trans-Anal Total Mesorectal Excision.

BACKGROUND: Trans-anal total mesorectal excision (Ta-TME) is a novel approach for the resection of rectal cancer. Low anterior resection syndrome (LARS) is a frequent functional disorder that might follow restorative proctectomy. Data regarding bowel function after Ta-TME are scarce. The aim of this study was to evaluate the incidence and risk factors for the development of LARS following Ta-TME. METHODS: A prospectively maintained database of all patients who underwent Ta-TME for rectal cancer at our institution was reviewed. All patients who were operated on from January 2018 to December 2021 were evaluated. The LARS score questionnaire was used via telephone interviews. Incidence, severity and risk factors for LARS were evaluated. RESULTS: Eighty-five patients underwent Ta-TME for rectal cancer between January 2018 and December 2021. Thirty-five patients were excluded due to ostomy status, death, local disease recurrence, ileal pouch or lack of compliance. Fifty patients were included in the analysis. LARS was diagnosed in 76% of patients. Anastomosis distance from dentate line was identified as a risk factor for LARS via multivariate analysis (p = 0.042). Neo-adjuvant therapy, hand sewn anastomosis and anastomotic leak did not increase the risk of LARS. CONCLUSION: LARS is a frequent condition following ta-TME, as it is used for other approaches to low anterior resection. Anastomosis distance from dentate line is an independent risk factor for LARS. In this study neo-adjuvant therapy, hand sewn anastomosis and anastomotic leak did not increase the risk of LARS. Further studies with longer follow-up times are required to better understand the functional outcomes following Ta-TME.

A patient tailored approach to the surgical treatment of hemorrhoids leads to equal satisfaction following hemorrhoidectomy, stapled hemorrhoidopexy or a combination of both.

PURPOSE: Up to 20% of patients suffering from symptomatic hemorrhoids will require surgery. Excisional hemorrhoidectomy (EH) and stapled hemorrhoidopexy (SH) are both standard and safe procedures. While SH has a short-term advantage of faster recovery and lower postoperative pain, its long-term efficacy is debatable. This study aims to compare the outcomes of EH, SH, and a combined procedure of both. METHODS: A retrospective study compared the outcomes of patients treated surgically for hemorrhoids over a 5-year period. Eligible patients were asked by phone to complete a questionnaire evaluating recurrent symptoms, fecal incontinence, satisfaction, and self-assessed improvement in quality of life (QOL). RESULTS: This study included 362 patients, of whom 215 underwent SH, 99 underwent EH, and 48 underwent a combined procedure. No statistically significant differences were found between groups regarding complications, symptoms recurrence, or fecal incontinence. Combined procedure patients had significantly higher self-assessed improvement in QOL (P=0.04). CONCLUSION: In patients with symptomatic hemorrhoids, a tailored approach to symptomatic hemorrhoids is associated with high satisfaction rates and self-assessed improvement in QOL.

A DNA methylation atlas of normal human cell types.

DNA methylation is a fundamental epigenetic mark that governs gene expression and chromatin organization, thus providing a window into cellular identity and developmental processes1. Current datasets typically include only a fraction of methylation sites and are often based either on cell lines that underwent massive changes in culture or on tissues containing unspecified mixtures of cells2-5. Here we describe a human methylome atlas, based on deep whole-genome bisulfite sequencing, allowing fragment-level analysis across thousands of unique markers for 39 cell types sorted from 205 healthy tissue samples. Replicates of the same cell type are more than 99.5% identical, demonstrating the robustness of cell identity programmes to environmental perturbation. Unsupervised clustering of the atlas recapitulates key elements of tissue ontogeny and identifies methylation patterns retained since embryonic development. Loci uniquely unmethylated in an individual cell type often reside in transcriptional enhancers and contain DNA binding sites for tissue-specific transcriptional regulators. Uniquely hypermethylated loci are rare and are enriched for CpG islands, Polycomb targets and CTCF binding sites, suggesting a new role in shaping cell-type-specific chromatin looping. The atlas provides an essential resource for study of gene regulation and disease-associated genetic variants, and a wealth of potential tissue-specific biomarkers for use in liquid biopsies.

Pneumatosis Cystoides Coli Presenting as Acute Abdomen in a Patient with Complicated Behcet's Disease: A Case Report.

BACKGROUND Behcet's disease (BD) is defined as vasculitis involving arteries and veins of any size and affecting almost any organ system. Abdominal manifestations of BD are diverse and nonspecific. Mucosal ulcerations can be seen in the gastrointestinal tract. Extensive ulcerations, especially ileocecal lesions, can lead to perforation, strictures, fistulas, and abscesses. Pneumatosis cystoides intestinale is a rare benign condition characterized by multiple submucosal or subserosal, gas-filled cysts in the gastrointestinal tract wall. Pneumatosis cystoides coli (PCC) affects the colon, can present with a wide range of manifestations, and can mimic many different systemic diseases. We describe a case of PCC in a patient with Behcet's disease who presented to the Emergency Department with a clinical suspicion of acute abdomen. CASE REPORT A 40-year-old man with complicated Behcet's disease, treated with high-dose steroids, presented with acute abdomen and CT scan findings highly suggestive of intestinal obstruction due to ileocolic intussusception. He underwent laparoscopic right hemicolectomy. Pathology demonstrated PCC disease. CONCLUSIONS Pneumatosis cystoides coli can present with a broad range of symptoms and can be secondary to many systemic and autoimmune diseases. With radiological evidence and a high level of suspicion, unnecessary surgery can be prevented.

Paraneoplastic syndrome due to angiomatoid fibrous histiocytoma: a known presentation of an uncommon diagnosis in a rare site and age.

A woman in her 70s presented with a small subcutaneous retrosacrococcygeal mass and a history of elevated erythrocyte sedimentation rate present for several years. It was misdiagnosed as an inflammatory process of unclear origin. She underwent further investigation with the appearance of weight loss and weakness. A sacrococcygeal mass was noted on CT scan. A core needle biopsy was inconclusive for chordoma versus myoepithelioma. Wide surgical resection of the tumour including the coccygeal bone was performed. Following surgery, all the systemic symptoms resolved with normalisation of inflammatory markers. The pathological examination showed a relatively circumscribed multinodular myxoid tumour with lymphatic tissue cuff. Pan-sarcoma fusion analysis detected an EWSR1 (Exon7)-CREB1 (Exon7) fusion gene. The lesion was diagnosed as angiomatoid fibrous histiocytoma with paraneoplastic syndrome presentation of several years' duration.

Urinary dysfunction in women following total mesorectal excision versus partial mesorectal excision for treatment of rectal cancer.

BACKGROUND: Colorectal cancer is a condition which is associated with substantial morbidity and mortality. The aim of this study was to assess urinary dysfunction and its effect on quality of life in women who underwent total mesorectal excision compared to women treated by partial mesorectal excision for treatment of rectal cancer. METHODS: We performed a retrospective cohort study at a tertiary university hospital between January 2014 and December 2019. A comparison was performed between women who underwent total mesorectal excision as opposed to partial mesorectal excision for treatment of rectal cancer. Pre-operative, intra-operative and post-operative data were compared between groups. Data regarding radiation therapy was recorded and compared as well. Urinary dysfunction and its impact on quality of life were assessed using UDI-6 and USIQ questionnaires. Further univariate and multivariate analyses were performed in the attempt of assessing risk factors for urinary dysfunction. RESULTS: A total of 107 women were included in the study, 73 women underwent partial mesorectal excision as opposed to 34 women who were treated by total mesorectal excision. Twenty-five women in the TME group underwent radiation therapy prior to surgery as opposed to none in the PME group (p < 0.001). Urinary dysfunction following surgery as assessed using the UDI-6 questionnaire did not differ between groups. Similar findings were recorded with regard to the impact of urinary dysfunction on quality of life as assessed using the USIQ questionnaire. Following multivariate analysis longer hospital stay was associated with increased risk of some degree of urinary dysfunction. CONCLUSIONS: Women undergoing total mesorectal excision have comparable results to partial mesorectal excision with regard to urinary dysfunction.

Dual energy CT in acute appendicitis: value of low mono-energy.

OBJECTIVES: To assess the potential role of low monoenergetic images in the evaluation of acute appendicitis. METHODS: A retrospective study of 42 patients with pathology proven acute appendicitis underwent contrast-enhanced-CT conducted on a single-source-DECT before surgery. Attenuation, SNR, and CNR were calculated on both monoenergetic and conventional images and compared to 24 abdominal CT-scans with normal appendix. Representative conventional and monoenergetic images were randomized and presented side-by-side to three abdominal radiologists to determine preferred images for detecting inflammation. Additionally, six individual acute inflammatory characteristics were graded on a 1-5 scale to determine factors contributing to differences between conventional and monoenergetic images by 2 abdominal radiologists. Paired t-tests, Wilcoxon and McNemar tests, and intra-observer error statistics were performed. RESULTS: For the inflamed appendixes monoenergetic images had overall increased attenuation (average ratio 1.7; P < 0.05), signal-to-noise-ratio (6.7 ± 3.1 vs 4.2 ± 1.6; P < 0.001) and contrast-to-noise-ratio (12.1 ± 3 vs 9 ± 2.1; P < 0.001). Moreover, this increase was not found in normal appendixes (P < 0.001 vs p = 0.28-0.44). Subjectively, radiologists showed significant preferences towards monoenergetic images (P < 0.001), with inter-reader agreement of 0.84. Two parameters, diffuse bowel wall and mucosal enhancement, received significantly higher scores on monoenergetic images (average 4.3 vs. 3.0; P < 0.001 and 2.8 vs. 2.3 P < 0.03 respectively, with interobserver agreements of 62% and 52%). CONCLUSION: Increased bowel wall conspicuity from enhanced attenuation, SNR, and CNR on low monenergetic CT images results in a significant preference by radiologists for these images when assessing acute inflamed appendixes. Thus, close inspection of low monoenergetic images may improve the visualization of acute inflammatory bowel processes.

Changes in abdominal wall thickness during laparoscopy: implications for the use of magnetic assisted surgery.

Introduction: Recently, magnetic solutions have been proposed to minimize surgical invasiveness. These are comprised of deployable instruments containing magnets which are inserted into the abdominal cavity through a single access point. The manipulation of the internal elements occurs via magnets held on the external surface of the abdominal wall. This technology relies on the magnetic force between the magnets, which is inversely related to the abdominal wall thickness (AWT). The aim of this study was to establish the expected change in AWT from before and after initiation of pneumoperitoneum. Material and methods: Patients scheduled for laparoscopic procedures were assessed by ultrasound for AWT immediately before and during laparoscopy. Change of AWT during laparoscopy was calculated. Statistical analysis was performed using Student's t-test. Results: Thirty-two patients undergoing various laparoscopic procedures were included. Twenty patients were male (62.5%) and ten were morbidly obese (31%). Mean age was 51 years (range 18-76) and average BMI was 28.1 kg/m2 (range 19.0-41.0). AWT decreased on average by 15.6% once pneumoperitoneum was initiated in both obese and non-obese patients (p = .01). Conclusion: Our data suggest that following preoperative assessment of AWT with abdominal wall ultrasound, more patients than expected might be candidates for the use of trans-abdominal magnetic devices.

Binding of the Fap2 protein of Fusobacterium nucleatum to human inhibitory receptor TIGIT protects tumors from immune cell attack.

Bacteria, such as Fusobacterium nucleatum, are present in the tumor microenvironment. However, the immunological consequences of intra-tumoral bacteria remain unclear. Here, we have shown that natural killer (NK) cell killing of various tumors is inhibited in the presence of various F. nucleatum strains. Our data support that this F. nucleatum-mediated inhibition is mediated by human, but not by mouse TIGIT, an inhibitory receptor present on all human NK cells and on various T cells. Using a library of F. nucleatum mutants, we found that the Fap2 protein of F. nucleatum directly interacted with TIGIT, leading to the inhibition of NK cell cytotoxicity. We have further demonstrated that tumor-infiltrating lymphocytes expressed TIGIT and that T cell activities were also inhibited by F. nucleatum via Fap2. Our results identify a bacterium-dependent, tumor-immune evasion mechanism in which tumors exploit the Fap2 protein of F. nucleatum to inhibit immune cell activity via TIGIT.

Current status of laparoscopy for the treatment of rectal cancer.

Surgery for rectal cancer in complex and entails many challenges. While the laparoscopic approach in general and specific to colon cancer has been long proven to have short term benefits and to be oncologically safe, it is still a debatable topic for rectal cancer. The attempt to benefit rectal cancer patients with the known advantages of the laparoscopic approach while not compromising their oncologic outcome has led to the conduction of many studies during the past decade. Herein we describe our technique for laparoscopic proctectomy and assess the current literature dealing with short term outcomes, immediate oncologic measures (such as lymph node yield and specimen quality) and long term oncologic outcomes of laparoscopic rectal cancer surgery. We also briefly evaluate the evolving issues of robotic assisted rectal cancer surgery and the current innovations and trends in the minimally invasive approach to rectal cancer surgery.

Colorectal polyps and polyposis syndromes.

A polyp is defined as any mass protruding into the lumen of a hollow viscus. Colorectal polyps may be classified by their macroscopic appearance as sessile (flat, arising directly from the mucosal layer) or pedunculated (extending from the mucosa through a fibrovascular stalk). Colorectal polyps may also be histologically classified as neoplastic or as non-neoplastic (hyperplastic, hamartomatous, or inflammatory). The neoplastic polyps are of primary importance because they harbor a malignant potential, which represents a stage in the development of colorectal cancer. For this reason, it is essential to identify these polyps at a sufficiently early stage, when a simple outpatient procedure to remove them can interrupt the development of colorectal cancer and prevent disease and death. When invasive carcinoma arises in a polyp, careful consideration must be given to ensuring the adequacy of treatment. Although most neoplastic polyps do not evolve into cancer, it is well accepted that the majority of colorectal carcinomas evolve from adenomatous polyps; the sequence of events leading to this transformation is referred to as the adenoma-to-carcinoma sequence. The presence of a systemic process that promotes the development of multiple gastro-intestinal polyps is termed 'polyposis'. Hereditary gastro-intestinal polyposis syndromes account for approximately 1% of all cases of colorectal cancer and are associated with a broad spectrum of extra-colonic tumors. Early detection and accurate classification of these syndromes are essential, in order to initiate a surveillance program for the early detection of cancer. Several polyposis syndromes have been described, each having its own genetic basis and characteristic polyp distribution, clinical presentation, and malignancy risk. Diagnostic modalities and treatment options for neoplastic polyps-as well as the most prevalent polyposis syndromes-are reviewed below.

Reusable single-port access device shortens operative time and reduces operative costs.

BACKGROUND: In recent years, single-port laparoscopy (SPL) has become an attractive approach for performing surgical procedures. The pitfalls of this approach are technical and financial. Financial concerns are due to the increased cost of dedicated devices and prolonged operating room time. Our aim was to calculate the cost of SPL using a reusable port and instruments in order to evaluate the cost difference between this approach to SPL using the available disposable ports and standard laparoscopy. METHODS: We performed 22 laparoscopic procedures via the SPL approach using a reusable single-port access system and reusable laparoscopic instruments. These included 17 cholecystectomies and five other procedures. Operative time, postoperative length of stay (LOS) and complications were prospectively recorded and were compared with similar data from our SPL database. Student's t test was used for statistical analysis. RESULTS: SPL was successfully performed in all cases. Mean operative time for cholecystectomy was 72 min (range 40-116). Postoperative LOS was not changed from our standard protocols and was 1.1 days for cholecystectomy. The postoperative course was within normal limits for all patients and perioperative morbidity was recorded. Both operative time and length of hospital stay were shorter for the 17 patients who underwent cholecystectomy using a reusable port than for the matched previous 17 SPL cholecystectomies we performed (p < 0.001). Prices of disposable SPL instruments and multiport access devices as well as extraction bags from different manufacturers were used to calculate the cost difference. Operating with a reusable port ended up with an average cost savings of US$388 compared with using disposable ports, and US$240 compared with standard laparoscopy. CONCLUSION: Single-port laparoscopic surgery is a technically challenging and expensive surgical approach. Financial concerns among others have been advocated against this approach; however, we demonstrate herein that using a reusable port and instruments reduces operative time and overall operative costs, even beyond the cost of standard laparoscopy.

A novel totally internal laparoscopic liver retractor.

INTRODUCTION: Minimally invasive surgery is still in evolution. Throughout the past two decades numerous devices have been developed to enable safer and faster procedures, including anastomosis creating devices, energy sources, and superior imaging. However, retraction capabilities were put aside and currently, organ laparoscopic retraction is based on standard laparoscopic tools. In the era of minimizing the number of ports and shrinking their size, our aim was to develop internal retraction device that could be placed in the peritoneal cavity through a standard trocar, positioned for adequate retraction, and left in place for the entire procedure. These devices would obviate the need for inserting ports dedicated for retraction only and hence contribute to the reduction of the number of incisions. Herein, we present our initial experience with a novel internal liver retractor. MATERIALS AND METHODS: The Endolift retractor is a simple telescopic rod that has anchoring claws at each end. It can be inserted using 5 mm standard trocar using a dedicated applier and anchored to the peritoneum beside the liver edges thereby lifting the undersurface of the liver and exposing the organs underneath. To achieve retraction of the left lateral segment, the Endolift retractor is anchored lateral to the right diaphragmatic crus on 1 side and lateral to the falciform ligament on the other. RESULTS: A total of 14 operations were performed using the Endolift retractor for liver retraction including antireflux procedure, robotic-assisted Heller's myotomy, bariatric procedures, and bile duct exploration. The left lobe of the liver was adequately retracted and enabled access to the operating field. Repositioning was easily performed with progression of the surgery when necessary. CONCLUSIONS: Internal retraction devices such as the Endolift retractor for liver retraction are one step further in minimizing trauma to the abdominal wall during minimal invasive surgery. It obviates the need for extra incisions, frees up the surgeons' hands, and may enable performing complicated laparo-endoscopic single-site laparoscopy and natural orifice transluminal endoscopic surgery.

Does nasogastric tube decompression get used less often with laparoscopic and hand-assisted compared with open colectomy?

INTRODUCTION: Laparoscopic surgery is associated with well-known benefits, one of which is earlier return of bowel function. Since the laparoscopic approach to colon resections was introduced in the early 1990s, it has become the standard of care. Hand-assisted laparoscopic surgery (HALS) is a surgical approach in which dissection is facilitated by the surgeon's hand within the abdominal cavity during laparoscopy. The purpose of this study was to compare the incidence of postoperative ileus and the need for nasogastric tube (NGT) decompression in patients undergoing elective colon resections. METHODS AND PROCEDURES: Following institutional review board approval, we performed a retrospective review of a prospectively collected database. Included were patients who underwent elective left-sided large bowel resections between 2009 and 2012. Exclusion criteria were urgent operation, stoma creation, ASA IV classification, NGT left in place at the end of surgery, and postoperative anastomotic leakage. Patients were divided into three groups: laparoscopic surgery, HALS, and open surgery. We evaluated the incidence of postoperative ileus and the use of nasogastric decompression in each group. RESULTS: A total of 243 patients were included in this study; 73 patients underwent open surgery, 89 patients underwent HALS, and 81 patients underwent laparoscopic surgery. The proportion of patients who needed postoperative nasogastric decompression was significantly reduced in patients undergoing laparoscopic surgery (3.7%) or HALS (4.5%) compared with those who underwent open resection (17.8%). The time from surgery to first flatus and first bowel movement, the time to tolerate solid diet, and the total length of postoperative hospital stay also were all significantly reduced in the laparoscopic and HALS groups compared with the open surgery group. There were no significant differences in any of these measures between the laparoscopic group and the hand-assisted group. CONCLUSIONS: Like laparoscopy, HALS is associated with less postoperative ileus and necessitates less NGT decompression than does open surgery.

Endovascular management of blunt renal artery trauma.

BACKGROUND: Renal artery injuries are rarely encountered in victims of blunt trauma. However, the rate of early diagnosis of such injuries is increasing due to increased awareness and the liberal use of contrast-enhanced CT. Sporadic case reports have shown the feasibility of endovascular management of blunt renal artery injury. However, no prospective trials or long-term follow-up studies have been reported. OBJECTIVES: To present our experience with endovascular management of blunt renal artery injury, and review the literature. METHODS: We conducted a retrospective study of 18 months at a level 1 trauma center. Search of our electronic database and trauma registry identified three patients with renal artery injury from blunt trauma who were successfully treated endovascularly. Data recorded included the mechanism of injury, time from injury and admission to revascularization, type of endovascular therapy, clinical and imaging outcome, and complications. RESULTS: Mean time from injury to endovascular revascularization was 193 minutes and mean time from admission to revascularization 154 minutes. Stent-assisted angioplasty was used in two cases, while angioplasty alone was performed in a 4 year old boy. A good immediate angiographic result was achieved in all patients. At a mean follow-up of 13 months the treated renal artery was patent in all patients on duplex ultrasound. The mean percentage renal perfusion of the treated kidney at last follow-up was 36% on DTPA renal scan. No early or late complications were encountered. CONCLUSIONS: Endovascular management for blunt renal artery dissection is safe and feasible if an early diagnosis is made. This approach may be expected to replace surgical revascularization in most cases.

Miniature camera for enhanced visualization for single-port surgery and NOTES.

OBJECTIVE: Natural orifice translumenal endoscopic surgery (NOTES) and single-port surgery (SPS) have maximized the enhanced aesthetic profile of laparoscopic surgery. Nevertheless, these modalities also accentuate the inherent limitations of subvisibility and decreased instrument dexterity of motion. The goal of this study was to evaluate the utility of a miniature laparoscopic camera to alleviate these obstacles. MATERIALS AND METHODS: A miniature laparoscopic camera was inserted via an endoscopic working channel or embedded into laparoscopic tools. Following laparoscopic trainer studies, operations were conducted on pigs using standard laparoscopic, SPS, and NOTES approaches. Additionally, the camera was used to perform colonoscopies on mice, rats, and pigs. RESULTS: The camera enabled visualizing the dissection area behind the renal vessels during laparoscopic nephrectomy and in the Triangle of Calot in laparoscopic cholecystectomy while providing accurate and detailed visualization of the operative field. The camera was successfully passed through the working channel of a standard gastroscope and used during NOTES procedures. It was used during colonoscopy to evaluate the distal colon in pigs and allowed the diagnosis of small colonic polyps with good image quality. Additionally, it could be easily passed beyond colonic strictures created in a porcine model. Finally, its miniature size enabled performance of colonoscopies on rats serving as animal models for colonic polyps. CONCLUSIONS: The miniature laparoscopic camera provides adequate images with enhanced visibility in conventional laparoscopic, SPS, and NOTES procedures. We believe that this device or similar miniature cameras may greatly aid the future development of NOTES and SPS by enhancing the safety and ease of performing these procedures. Further development is being conducted in order to integrate this camera into standard instruments and to allow an even better image quality.

Laparoscopic partial nephrectomy using a flexible CO2 laser fiber.

BACKGROUND AND OBJECTIVES: Laparoscopic partial nephrectomy (LPN) is a challenging surgery that requires precise tissue cutting and meticulous hemostasis under warm ischemia conditions. In this study, we tested the feasibility of performing LPN using CO2 laser energy transmitted through a specialized flexible mirror optical fiber. METHODS: General anesthesia and pneumoperitoneum were induced in 7 farm pigs. Various portions of a kidney, either a pole or a midportion of the kidney, were removed using a novel flexible fiber to transmit CO2 laser energy set at a power of 45W and energy per pulse of 100mJ. The collecting system was approximated with a suture or 2, but no hemostatic measures were taken besides applying a few pulses of the laser to bleeding points. The pigs were sacrificed 3 wk later. RESULTS: Average renal mass removed was 18% of the total kidney weight. All pigs tolerated surgery well. Sharp renal cutting was accomplished in a single continuous incision, with minimal tissue charring and minimal blood loss (<10cc) in all animals. Necropsy revealed no peritoneal or retroperitoneal abnormalities. Histologic examination of the cut surface showed a thin sector of up to 100 m of coagulation necrosis. CONCLUSIONS: We report on the first LPN done using a CO2 laser transmitted through a flexible fiber in an animal model. This novel application of the CO2 laser produced excellent parenchymal incision and hemostasis along with minimal damage to adjacent renal tissue, thus, potentially shortening ischemia time and kidney function loss. Further studies comparing this laser to standard technique are necessary to verify its usefulness for partial nephrectomy.