Jejunal vein tributary analysis and intraoperative clamp testing in avoiding congestion after pancreatoduodenectomy.

PURPOSE: Although venous drainage of the jejunal loop may be maintained after sacrifice of jejunal vein tributaries during pancreatoduodenectomy, risk of severe jejunal mesenteric congestion following division of these tributaries can be difficult to predict. This study considered how best to predict safety of jejunal vein tributary dissection. METHODS: Preoperative imaging findings and results of intraoperative clamp tests of jejunal vein tributaries during pancreatoduodenectomy were analyzed in 121 patients with hepatobiliary and pancreatic disease to determine whether this information adequately predicted safety of resecting superior mesenteric vein branches. RESULTS: Jejunal vein tributaries caudal to the inferior border of the pancreatic uncinate process tended to be fewer when tributaries cranial to this landmark were more numerous. Tributaries cranial to the border drained a relatively wide expanse of jejunal artery territory in the jejunal mesentery. The territory of jejunal tributaries cranial to the inferior border of the pancreas did not vary according to course of the first jejunal vein branch relative to the superior mesenteric artery. One patient among 30 (3%) who underwent intraoperative clamp tests of tributaries cranial to the border showed severe congestion in relation to a venous tributary coursing ventrally to the superior mesenteric artery. CONCLUSION: Jejunal venous tributaries drained an extensive portion of jejunal arterial territory, but tributaries located cranially to the inferior border of the pancreas could be sacrificed without congestion in nearly all patients. Intraoperative clamp testing of these tributaries can identify patients whose jejunal veins must be preserved to avoid congestion.

Full-Circumference Prosthetic Grafts for Replacing a Retrohepatic Inferior Vena Cava Segment During Hepatectomy for Tumor.

BACKGROUND: Although hepatectomy including inferior vena cava (IVC) resection is becoming more common, some details remain uncertain such as use of artificial materials to replace a tumor-involved, damaged, or narrowed retrohepatic IVC segment. METHODS: Surgical outcomes of 12 patients who underwent hepatectomy with IVC resection including reconstruction using synthetic tubular grafts were investigated to clarify safety and feasibility. RESULTS: Operative time (median, 573 min; range, 268 to 774) and the blood loss (1076 mL; 155 to 2960) were acceptable. In-hospital mortality was 8% (1/12), and morbidity was 42% (5/12). Among the 12 patients, 2 were planned to undergo IVC reconstruction without an artificial graft. In one patient, prosthetic repair was adopted because of massive bleeding from the IVC wall during dissection of tumor from the IVC. In the other, severe stricture became evident during attempted direct closure of the partially resected IVC wall. DISCUSSION: Ongoing experience has increased our acceptance of combined liver and IVC resection. We believe that segmental IVC resection and reconstruction with a prosthetic tubular graft could be chosen more frequently in managing liver tumors suspected to involve the IVC.

Percutaneous transhepatic gallbladder drainage versus endoscopic gallbladder stenting for managing acute cholecystitis until laparoscopic cholecystectomy.

INTRODUCTION: Gallbladder drainage by methods such as percutaneous transhepatic gallbladder drainage (PTGBD) or endoscopic gallbladder stenting (EGBS) is important in the early management of moderate to severe acute cholecystitis. METHODS: In patients undergoing laparoscopic cholecystectomy (LC) for acute cholecystitis after a month or more of gallbladder drainage, the clinical course was compared between patients initially treated with PTGBD or EGBS. RESULTS: Among 331 patients undergoing LC for cholecystitis between 2018 and 2022, 43 first underwent 1 or more months of gallbladder drainage. The median interval between drainage initiation and LC was 89 days (range, 28-261) among 34 patients with PTGBD and 70 days (range, 62-188) among nine with EGBS (p = 0.644). During this waiting period, PTGBD was clamped in six patients and removed in five. Cholecystitis relapsed in three PTGBD patients (9%) and four EGBS patients (44%; p = 0.026). Relapses were managed with medications. Cholecystectomy duration (p = 0.022), intraoperative blood loss (p = 0.026), frequency of abdominal drain insertion (p = 0.023), and resort to bailout surgery such as fundus-first approaches (p = 0.030) were significantly greater in patients with EGBS. Postoperative complications were somewhat likelier (p = 0.095) and postoperative hospital stays were longer (p = 0.007) in the EGBS group. CONCLUSION: Among patients whose LC was performed 1 or more months after initiation of drainage, daily living during the waiting period associated with drainage was well supported by EGBS, but LC and the postoperative course were more complicated than in PTGBD patients.

Failure of peritoneal lavage to prevent operative site infection and peritoneal tumor recurrence in pancreatic surgery.

BACKGROUND: Although intraoperative peritoneal lavage often is performed routinely with the aim of reducing peritoneal contamination, evidence of lavage benefit in elective pancreatic surgery is limited. METHODS: We retrospectively classified patients who had undergone pancreatic surgery to groups given or not given peritoneal lavage, then comparing clinical results. This saline lavage was performed at the end of the operation. The primary endpoint was rate of surgical site infection. Frequency of peritoneal recurrence also was evaluated. RESULTS: Among all 104 patients in the study, incidence of infectious complications in the lavage group (n = 65) was significantly higher than in the non-lavage group (n = 39; 35% vs. 15%, P = 0.041), while incidences of postoperative complications overall and surgical site infection did not differ between lavage (80% and 26%) and non-lavage groups (67% and 10%, P = 0.162 and 0.076, respectively). Among 63 patients undergoing pancratoduodenectomy, frequencies of positive bacterial cultures of drainage fluids on postoperative days 1 and 3 were greater in the non-lavage group (P < 0.001 and P = 0.012), but surgical site infection was significantly more frequent in the lavage group (P = 0.043). Among patients with pancreatic and biliary cancers, lavage did not affect frequency of peritoneal recurrence. CONCLUSION: Intraoperative lavage did not prevent surgical site infection or peritoneal recurrence of pancreatobiliary cancer.

Computed tomography findings of intersigmoid hernia.

Purpose: To evaluate the computed tomography findings of intersigmoid hernias. Material and methods: Between April 2010 and March 2018, 7 patients who were surgically diagnosed with intersigmoid hernia in 3 institutions were enrolled in this study. Two radiologists evaluated imaging findings for the herniated small bowel, the distance between the occlusion point and bifurcation of the left common iliac artery, and the anatomic relationship with adjacent organs. Results: All patients were male, and their mean age (standard deviation, range) was 61.0 (13.5, 36-85) years. The mean size of the bowel loops was 5.2 (1.3, 4.0-8.3) cm in the caudal direction, 3.6 (0.8, 2.5-5.1) cm in the lateral, and 3.4 (0.6, 2.5-4.7) cm in the anterior-posterior direction. The volume was 37.9 (27.8, 15.6-103.0) cm3 approximated by an ellipse, and 24.0 (17.7, 9.9-65.6) cm3 approximated by a truncated cone. The obstruction point was located 3.6 (0.6, 2.8-4.7) cm inferior to the bifurcation of the left common iliac artery. In all cases, the small bowel ran under the point at which the inferior mesenteric vessels bifurcated to the superior rectal vessels and the sigmoid vessels and formed a sac-like appearance between the left psoas muscle and the sigmoid colon. The ureter ran dorsal to the point of the bowel stenosis, and the left gonadal vein ran outside the small bowel loops. Conclusions: All cases showed common imaging findings, which may be characteristic of men's intersigmoid hernia. In addition, the fossa's position was lower, and the size was larger than in the previous study, which may be a risk factor.

Prognostic implications of histologic growth patterns and tumor-infiltrating macrophages in colorectal liver metastases.

PURPOSE: Histopathologic patterns at the invasion fronts of tumors predict metastatic potential and prognosis in several cancers. We examined whether such patterns at the interface between colorectal liver metastases and hepatic parenchyma have similar prognostic value. METHODS: Microscopic growth patterns at edges of metastases including desmoplasia, pushing borders, and replacement of hepatocytes were retrospectively analyzed with respect to surgical outcomes in 142 patients who underwent hepatectomy for colorectal metastases. RESULTS: Patterns included desmoplasia in 58 patients (41%), hepatocyte replacement in 41 (29%), and pushing borders in 43 (30%). Maximum metastasis diameter and serum carcinoembryonic antigen concentration in patients showing desmoplastic tumor growth were lower than those in others (P < 0.05 and P < 0.01). Disease-free survival and overall survival were better in patients showing desmoplastic growth, while a non-desmoplastic tumor growth pattern showed a negative influence. More cluster of differentiation (CD) 68-positive M1 macrophages and fewer CD206-positive M2 macrophages were demonstrated at interfaces of tumors with hepatic parenchyma when desmoplasia was present, although markers for proliferative activity (MIB1 index) and metastatic potential (E-cadherin expression) appeared uninfluenced by desmoplasia. CONCLUSION: Better long-term results were associated with metastatic tumors showing desmoplastic growth patterns at invasion fronts, which may reflect local immune state in a prognostically useful manner.

How to do repeat hepatectomy for remnant liver recurrence using diaphragmatic incision for right liver mobilization.

In addition to difficulties with parenchymal resection reflecting anatomic disorientation arising from rotation of the liver remnant that accompanies regeneration, repeat resections typically involve difficult and protracted lysis of adhesions. We describe our technique for facilitating right liver mobilization even in the presence of severe adhesions. Lysis of dense retroperitoneal adhesions posterior to the right liver can be performed safely by incising the diaphragm to facilitate manipulations to mobilize the right liver.

Absence of a weekday effect on short- and long-term oncologic outcomes of gastrectomy for gastric cancer: a propensity score matching analysis.

BACKGROUND: Day of the week when elective gastrointestinal surgery is performed may be influenced by various background and tumor-related factors. Relationships between postoperative outcome and when in the week gastrectomy is performed remain controversial. We undertook this study to evaluate whether weekday of gastrectomy influenced outcomes of gastric cancer treatment ("weekday effect"). METHODS: Patients who underwent curative surgery for gastric cancer between 2004 and 2017 were included in this retrospective study. To obtain 2 cohorts well balanced for variables that might influence clinical outcomes, patients whose gastrectomy was performed early in the week (EW group) were matched 1:1 with others undergoing gastrectomy later in the week (LW group) by use of propensity scores. RESULTS: Among 554 patients, 216 were selected from each group by propensity score matching. Incidence of postoperative complications classified as Clavien-Dindo grade II or higher was similar between EW and LW groups (20.4% vs. 24.1%; P = 0.418). Five-year overall and recurrence-free survival were 86.0% and 81.9% in the EW group, and 86.2% and 81.1% in the LW group (P = 0.981 and P = 0.835, respectively). CONCLUSIONS: Short- and long-term outcomes were comparable between gastric cancer patients who underwent gastrectomy early and late in the week.

Modification of ALPPS to avoid ischemia and congestion after stage 1: a case report.

BACKGROUND: Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has been advocated for treating advanced liver tumors, but the devascularized ischemic area resulting from liver parenchymal division can become a nidus for sepsis. We present a patient who underwent ALPPS modified to avoid ischemia and congestion after liver partitioning during stage 1. CASE PRESENTATION: ALPPS was carried out for a patient with multiple bilobar liver metastases from rectosigmoid colon cancer. The 2-stage treatment included 3 partial resections within the left lateral section and parenchymal division at the umbilical fissure with right portal vein ligation as stage 1, followed by right trisectionectomy as stage 2. During parenchymal division at the umbilical fissure, Segment 4 portal pedicles and the middle hepatic vein had to be resected at their roots. To safely accomplish this, combined resection of Segment 4 and the drainage area of the middle hepatic vein was performed after parenchymal partition, aiming to avoid ischemia and congestion within the remnant liver. Successful stage 2 hepatectomy followed later. No ischemia or congestion occurred during stage 1 or 2. CONCLUSIONS: During ALPPS, ischemia and congestion after stage 1 must be avoided to reduce morbidity and mortality. The modification described here should reduce likelihood of severe postoperative complications.

Benefit of laparoscopic compared to standard open gastric cancer surgery for sarcopenic patients: a propensity score-matching analysis.

BACKGROUND: Laparoscopic gastrectomy (LG) is performed widely, but whether LG is the optimal treatment for sarcopenic gastric cancer patients is unclear. This study aimed to determine whether LG is particularly beneficial for gastric cancer patients with sarcopenia. METHODS: We collected data concerning 604 consecutive patients who underwent gastrectomy for gastric cancer between January 2003 and December 2019. After adjustment using one-to-one propensity score matching, short-term and long-term outcomes were compared between LG and open gastrectomy (OG) groups among patients with sarcopenia and those without. RESULTS: Among patients with and without sarcopenia, the LG group had a significantly longer operative time but less blood loss than the OG group. The two groups showed no significant differences regarding complications. Although 5-year overall and disease-specific survival were similar between LG and OG groups among patients with and without sarcopenia, LG was associated with greater 5-year non-gastric cancer-related survival than OG among patients with sarcopenia (88.3% vs. 78.1%, P = 0.048), but not those without. CONCLUSION: LG for resectable gastric cancer was not inferior to OG regarding complications and outcomes in patients with or without sarcopenia. No difference in overall survival was evident between these approaches, but LG may lessen mortality from conditions unrelated to gastric cancer in sarcopenic patients.

Impact of body fat and muscle quantity on short- and long-term outcome after gastrectomy for cancer.

BACKGROUND & AIMS: Preoperative low skeletal muscle mass and obesity have been identified as poor prognostic factors after gastrectomy for cancer, but the predictive value of combined quantitation of skeletal muscle mass and obesity remains unclear. This study examined the impact of combined body compositions on outcomes after gastrectomy for cancer. METHODS: 518 patients who had undergone gastric resection for cancer between 2004 and 2017 were analyzed retrospectively. Skeletal muscle mass (skeletal muscle mass index (SMI)) and visceral obesity (visceral fat area) were measured in preoperative computed tomographic images to categorize patients as outlined below. Impacts of these body compositions on outcomes after gastrectomy were investigated. RESULTS: Body composition was classified as high SMI without obesity in 231 patients (45%), high SMI with obesity in 202 (39%), low SMI without obesity in 55 (11%), and low SMI with obesity in 30 (6%). Postoperative complications developed in 128 patients (25%). Multivariate analysis identified low SMI with obesity as an independent risk factor for postoperative complications (odds ratio, 3.27; P = 0.010). Moreover, patients with low SMI without obesity had lower 5-year overall survival rates than patients with high SMI without obesity (64.4% vs. 88.0%; P < 0.001) and worse 5-year relapse-free survival rates (61.3% vs. 81.3%; P = 0.002). Multivariate analysis identified low SMI without obesity as a significant risk factor for overall survival (hazard ratio, 3.033; P < 0.001) and relapse-free survival (hazard ratio, 2.144; P = 0.008) after gastrectomy. CONCLUSION: Preoperative low SMI with obesity was an independent risk factor for postoperative complications, while low SMI without obesity was an independent risk factor for overall and relapse-free survival following gastrectomy for cancer.

Chemotherapy-induced Reversion of Mutant RAS to Wild-type RAS in Metastatic Colorectal Cancer.

BACKGROUND/AIM: Secondary mutation of mutated RAS, induced by chemotherapy, is thought to be rare. However, introduction of liquid biopsy (LB) has made it possible to monitor RAS status in patients' plasma throughout the course of chemotherapy for metastatic colorectal cancer (mCRC), and disappearance of the RAS mutation (RAS-mt), i.e., the NeoRAS-wt phenomenon, has been reported and is receiving attention, especially with respect to treatment implications. PATIENTS AND METHODS: A prospective study of 129 patients undergoing chemotherapy for mCRC (RAS-wt, n=65; RAS-mt, n=64) was carried out. Plasma RAS status was monitored in these patients by LB. Relations between secondary genetic change, chemotherapy, and 6-month disease outcomes were analyzed. The effect of anti-EGFR mAb therapy on NeoRAS-wt mCRC was also examined. RESULTS: NeoRAS-wt was detected in 27 (43.5%) RAS-mt patients overall and in all patients with a G12S or Q61H mutation. First-line treatment was more effective among NeoRAS-wt patients than non-NeoRAS-wt patients (70.9% vs. 48.6% overall response rate, p=0.087), and the time from treatment to LB was shorter in this group. Six-month outcomes were significantly better in the NeoRAS-wt group (p<0.001), and conversion to NeoRAS-wt was found to be predictive of a good outcome (OR=7.886, 95% CI=2.458-25.30; p<0.001). Anti-EGFR mAb therapy was found to restrict disease progression in NeoRAS-wt patients. CONCLUSION: Conversion to NeoRAS-wt is relatively frequent, and it may predict good responses to treatment. Anti-EGFR mAb therapy was effective for our NeoRAS-wt patients. Detection of NeoRAS-wt by LB may significantly change the indication for anti-EGFR mAb therapy and the mCRC treatment strategy.

Superior mesenteric vein reconstruction during pancreatoduodenectomy using a dilated right ovarian vein in a patient at future risk for pelvic congestion syndrome: a case report.

BACKGROUND: Pancreatoduodenectomy including resection of the superior mesenteric vein (SMV) is increasingly performed for right-sided pancreatic ductal adenocarcinoma invading the wall of that vessel. Various venous grafts may be chosen for reconstruction. We present a woman with pancreatic cancer who underwent such a pancreatoduodenectomy with venous reconstruction using a dilated right ovarian vein. CASE PRESENTATION: A 71-year-old woman with cancer involving the pancreatic head, uncinate process, and SMV underwent pancreatoduodenectomy with SMV resection. Reconstruction used a portion of the right ovarian vein that was markedly dilated and had placed her at risk for pelvic congestion syndrome (PCS). Graft patency was confirmed 8 months after surgery. She now finished receiving adjuvant chemotherapy and has no symptoms of PCS. CONCLUSION: If an ovarian vein has sufficient diameter, it can be used to reconstruct the resected segment of the SMV during pancreatoduodenectomy in suitable patients.

[Prehepatectomy Chemotherapy Using Circadian Chrono-HAI for Liver Metastases from Colorectal Cancer].

We investigated the safety and efficacy of circadian chronotherapy via the hepatic artery(chrono-HAI)as a prehepatectomy chemotherapy for initially unresectable colorectal liver metastases. Five-day course of chrono-HAI using 5-FU, l-LV, and L-OHP plus systemic panitumumab with 9-day interval were administered to 24 patients with failure for previous chemotherapy. Response rate and Grade 3 adverse effect(AE) were 63% and 54%, respectively. Among 22 patients( excluding 2 CR patients), conversion surgery could be performed in 10(45%). Two-year overall survival of patients with surgery (58%)was longer in those without(20%, p=0.057). Although incidence of AE was a bit high, chrono-HAI plus systemic panitumumab is an effective prehepatectomy chemotherapy for patients with aggressive colorectal liver metastases.

Preoperative Pre-albumin Concentration as a Predictor of Short-term Outcomes in Elderly Patients With Colorectal Cancer.

BACKGROUND/AIM: Population aging results in increasing numbers of elderly persons undergoing surgery for colorectal cancer. We sought to identify objective preoperative indicators of outcomes, with a view toward development of safe, effective treatments for such patients. PATIENTS AND METHODS: The study included 99 patients aged 80 years or more, who were treated surgically for stage I- III colorectal cancer. Preoperative nutritional status was compared retrospectively between those who suffered postoperative complications (n=40) and those who did not (n=59). RESULTS: Univariate analysis revealed low prealbumin (PreAlb) concentration (p=0.032) and low platelet-to-lymphocyte ratio (p=0.116) as risk factors for postoperative complications. Multivariate analysis showed preoperative PreAlb concentration to be an independent risk factor (OR=0.884; 95% confidence interval=0.791-0.989; p=0.024) associated with postoperative length of hospital stay (coef.=-0.336, p=0.002). CONCLUSION: PreAlb, a rapid turnover protein, shows promise as a simple predictor of postoperative complications in elderly patients treated for colorectal surgery.

Comparative Study of an Ultrasound-guided Percutaneous Biopsy and Endoscopic Ultrasound-guided Fine-needle Aspiration for Liver Tumors.

Objective Both a percutaneous biopsy and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) have been widely performed for liver tumors. However, no studies have compared these two biopsy methods. Method A retrospective study was conducted using medical records for patients who underwent a liver tumor biopsy from 2012 to 2019. The cases were classified into two groups for a comparison: an ultrasound-guided percutaneous biopsy group (percutaneous group) and an EUS-FNA group (EUS group). Results A total of 106 patients (47 in the percutaneous group and 59 in the EUS group) were included. The final diagnosis was malignant in 100 cases and benign in the remaining 6 cases. While the median lesion diameter was 62 mm in the percutaneous group, it was significantly smaller (34 mm) in the EUS group (p <0.01). The EUS group had more left lobe tumors than right lobe tumors. All cases of caudate lobe tumor (four cases) underwent EUS-FNA. The sensitivity, specificity, and accuracy of the procedure were 95%, 100%, and 96% in the percutaneous group and 100%, 100%, and 100% in the EUS group, respectively showing no significant difference. Adverse events were reported in 17% of the percutaneous group, which was significantly lower than in the EUS group (2%; p <0.01). Conclusion A percutaneous biopsy and EUS-FNA have equivalent diagnostic qualities for liver tumors, although EUS-FNA tends to be associated with fewer adverse events. A complete understanding of the characteristics of each procedure is essential when choosing the best biopsy method for each particular case.

A case of bile duct diverticulum with repeated acute cholangitis due to diverticular stone fall.

A 34-year-old man presented to the emergency department with a chief complaint of epigastric pain. Endoscopic ultrasound detected a 5 mm stone in the common bile duct. After endoscopic sphincterotomy, the black stones and debris were removed with balloon catheter. Abdominal ultrasonography detected no gallbladder stones; hence, the patient was followed up. However, 3 months later, the patient again developed acute cholangitis caused by common bile duct stones and underwent endoscopic stone removal. Cholangiography under balloon occlusion revealed a left hepatic duct diverticulum with an internal defect. Intraductal ultrasonography showed a hyperechoic lesion with acoustic shadow in the diverticulum, suggesting a stone or debris. Therefore, the patient was considered to have had repeated acute cholangitis because of the presence of falling diverticular stones. The patient underwent left hemihepatectomy plus segmentectomy 1 and cholecystectomy. Histopathologically, it was a true diverticulum without internal epithelial atypia. Many debris were seen in the diverticulum. Gallbladder stones were not observed. Eventually, the patient was discharged from the hospital with no postoperative complications and no recurrence of cholangitis after 20 months.

Association between low preoperative skeletal muscle quality and infectious complications following gastrectomy for gastric cancer.

PURPOSE: It is known that sarcopenia affects the overall short- and long-term outcomes of patients with gastric cancer (GC); however, the effect of muscle quality on infectious complications after gastrectomy for GC remains unclear. We investigated the associations between the preoperative quantity and quality of skeletal muscle on infectious complications following gastrectomy for GC. METHODS: The subjects of this retrospective study were 353 GC patients who underwent radical gastrectomy between 2009 and 2018. We examined the relationships between their clinical factors, including skeletal muscle mass index and intramuscular adipose tissue content (IMAC), and infectious complications after gastrectomy. RESULTS: Infectious complications developed in 59 patients (16.7%). The independent risk factors for infectious complications identified by multivariate analysis were male gender (P < 0.001), prognostic nutritional index below 45 (P = 0.006), and high IMAC (P = 0.011). Patients with a high IMAC were older and had a higher body mass index, as well as a greater age-adjusted Charlson comorbidity index, than those with low or normal IMAC. CONCLUSIONS: Low skeletal muscle quality defined by a high IMAC is a risk factor for infectious complications following gastrectomy. When feasible, preoperative nutritional intervention and rehabilitation aiming to improve muscle quality could reduce infectious complications after gastrectomy for GC.

Automated non-invasive identification of pelvic autonomic nerves with a handheld Raman spectrometer and potential application to nerve-sparing colorectal surgery: a preliminary study in surgical specimens.

BACKGROUND: Although minimally invasive surgery for colorectal cancer, whether performed as standard laparoscopic or robotic surgery, has been established as an oncologically safe procedure, postoperative urinary dysfunction and sexual dysfunction remain matters of concern, even when so-called nerve-sparing surgery is performed. We have hypothesized that Raman spectroscopy can be used intraoperatively as a non-invasive label-free means of objective identification of the pelvic nerves, and we conducted a preliminary study by applying a newly developed handheld Raman spectrometer to surgical specimens. METHODS: Samples of nervous tissue, colon cancer tissue, and tissues from surrounding pelvic organs were obtained from 25 patients undergoing colectomy. Raman spectra were obtained by irradiation with the Progeny™ Raman spectrometer. We looked for characteristic Raman shifts to distinguish nervous tissue from cancer tissue. To improve discrimination between nervous tissue and other tissues, the spectral data were subjected to principal component analysis. RESULTS: We detected characteristic differences in the spectra at 1,309 cm-1, 1,442 cm-1, and 1,658 cm-1. A significant difference was detected at 1,442 cm-1, and accuracy of the modality for identification of nervous tissue was 75%. The addition of principle component analysis (4 components) yielded 100% sensitivity, 85% specificity, and 90%, notably increasing accuracy from 75% to 90% in discriminating between nervous tissue and cancer tissue. CONCLUSIONS: Raman spectroscopy holds promise for non-invasive intraoperative recognition of nervous tissue. We expect the modality to become a powerful clinical tool, compensating for the lack of tactile feedback intrinsic to minimally invasive colectomy and thus thwarting the risk of postoperative urinary and/or sexual dysfunction.