The Role of Preoperative Imaging in the Detection of Lateral Lymph Node Metastases in Rectal Cancer: A Systematic Review and Diagnostic Test Meta-analysis.

BACKGROUND: Different techniques exist for the imaging of lateral lymph nodes in rectal cancer. OBJECTIVE: This study aimed to compare the diagnostic accuracy of pelvic MRI, 18 F-FDG-PET/CT, and 18 F-FDG-PET/MRI for the identification of lateral lymph node metastases in rectal cancer. DATA SOURCES: Data sources include PubMed, Embase, Cochrane Library, and Google Scholar. STUDY SELECTION: All studies evaluating the diagnostic accuracy of pelvic MRI, 18 F-FDG-PET/CT, and 18 F-FDG-PET/MRI for the preoperative detection of lateral lymph node metastasis in patients with rectal cancer were selected. INTERVENTIONS: The interventions were pelvic MRI, 18 F-FDG-PET/CT, and/or 18 F-FDG-PET/MRI. MAIN OUTCOME MEASURES: Definitive histopathology was used as a criterion standard. RESULTS: A total of 20 studies (1,827 patients) were included out of an initial search yielding 7,360 studies. The pooled sensitivity of pelvic MRI was 0.88 (95% CI, 0.85-0.91), of 18 F-FDG-PET/CT was 0.83 (95% CI, 0.80-0.86), and of 18 F-FDG-PET/MRI was 0.72 (95% CI, 0.51-0.87) for the detection of lateral lymph node metastasis. The pooled specificity of pelvic MRI was 0.85 (95% CI, 0.78-0.90), of 18 F-FDG-PET/CT was 0.95 (95% CI, 0.86-0.98), and of 18 F-FDG-PET/MRI was 0.90 (95% CI, 0.78-0.96). The area under the curve was 0.88 (95% CI, 0.85-0.91) for pelvic MRI and was 0.83 (95% CI, 0.80-0.86) for 18 F-FDG-PET/CT. LIMITATIONS: Heterogeneity in terms of patients' populations, definitions of suspect lateral lymph nodes, and administration of neoadjuvant treatment. CONCLUSIONS: For the preoperative identification of lateral lymph node metastasis in rectal cancer, this review found compelling evidence that pelvic MRI should constitute the imaging modality of choice. In contrast, to confirm the presence of lateral lymph node metastasis, 18 F-FDG-PET/MRI modalities allow discarding false positive cases because of increased specificity. PROSPERO REGISTRATION NUMBER: CRD42020200319.

A systematic review of the literature assessing operative blood loss and postoperative outcomes after colorectal surgery.

PURPOSE: There is no consensus in the literature regarding the association between operative blood loss and postoperative outcomes in colorectal surgery, despite evidence suggesting a link. Therefore, this systematic review assesses the association between operative blood loss, perioperative and long-term outcomes after colorectal surgery. METHODS: A literature search of MEDLINE, EMBASE, Science Citation Index Expanded and Cochrane was performed to identify studies reporting on operative blood loss in colorectal surgery. RESULTS: The review included forty-nine studies reporting on 61,312 participants, with a mean age ranging from 53.4 to 78.1 years. The included studies demonstrated that major operative blood loss was found to be a risk factor for mortality, anastomotic leak, presacral abscess, and postoperative ileus, leading to an increased duration of hospital stay. In the long term, the studies suggest that significant blood loss was an independent risk factor for future small bowel obstruction due to colorectal cancer recurrence and adhesions. Studies found that survival was significantly reduced, whilst the risk of colorectal cancer recurrence was increased. Reoperation and cancer-specific survival were not associated with major blood loss. CONCLUSION: The results of this systematic review suggest that major operative blood loss increases the risk of perioperative adverse events and has short and long-term repercussions on postoperative outcomes. Laparoscopic and robotic surgery, vessel ligation technology and anaesthetic considerations are essential for reducing blood loss and improving outcomes. This review highlights the need for further high quality, prospective, multicentre trials with a greater number of participants, and accurate and standardised methods of measuring operative blood loss.

Systematic review and meta-analysis comparing perioperative outcomes of pediatric emergency appendicectomy performed by trainee vs trained surgeon.

Appendicectomy is a common pediatric surgical procedure performed by trainees and surgeons with varying reported outcomes. It is a benchmark procedure for trainee progression and training benefits should be weighed against patient safety and perioperative outcomes. This systematic review and meta-analysis investigated any differential perioperative outcomes dependent on the grade of the operating surgeon. A systematic literature review and meta-analysis were performed comparing outcomes of pediatric appendicectomy performed by trainees versus trained surgeons. Of 2,086 articles screened, 5 retrospective non-randomized comparative studies reporting on 10,019 participants were analyzed. There was no difference in overall complications (OR 0.92; 95% CI 0.76, 1.12; P = 0.42), major complications [Clavien-Dindo (CD) III/IV] (OR 1.18; 95% CI 0.71, 1.97; P = 0.52), minor complications (CD I/II) (OR 1.13; 95% CI 0.57, 2.27; P = 0.72), post-op ileus (OR 0.74; 95% CI 0.10, 5.26; P = 0.76), wound infections (OR 0.87; 95% CI 0.62, 1.21; P = 0.41), abscess formation (OR 0.58; 95% CI 0.28, 1.22; P = 0.15), operation times [Mean Difference (MD) 2.31 min; 95% CI - 4.94, 9.56; P = 0.53] and reoperation rate (OR 1.22; 95% CI 0.23, 6.42; P = 0.81). Trainees had fewer conversions to open appendicectomy (OR 0.14; 95% CI 0.02, 0.88; P = 0.04). Appendicectomy performed on pediatric patients by trainees did not compromise patient safety. LEVEL OF EVIDENCE: III.

The role of Neurotensin and its receptors in non-gastrointestinal cancers: a review.

BACKGROUND: Neurotensin, originally isolated in 1973 has both endocrine and neuromodulator activity and acts through its three main receptors. Their role in promoting tumour cell proliferation, migration, DNA synthesis has been studied in a wide range of cancers. Expression of Neurotensin and its receptors has also been correlated to prognosis and prediction to treatment. MAIN BODY: The effects of NT are mediated through mitogen-activated protein kinases, epidermal growth factor receptors and phosphatidylinositol-3 kinases amongst others. This review is a comprehensive summary of the molecular pathways by which Neurotensin and its receptors act in cancer cells. CONCLUSION: Identifying the role of Neurotensin in the underlying molecular mechanisms in various cancers can give way to developing new agnostic drugs and personalizing treatment according to the genomic structure of various cancers. Video abstract.

Open Versus Laparoscopic Versus Robotic Versus Transanal Mesorectal Excision for Rectal Cancer: A Systematic Review and Network Meta-analysis.

OBJECTIVE: To compare techniques for rectal cancer resection. SUMMARY BACKGROUND DATA: Different surgical approaches exist for mesorectal excision. METHODS: Systematic literature review and Bayesian network meta-analysis performed. RESULTS: Twenty-nine randomized controlled trials included, reporting on 6237 participants, comparing: open versus laparoscopic versus robotic versus transanal mesorectal excision. No significant differences identified between treatments in intraoperative morbidity, conversion rate, grade III/IV morbidity, reoperation, anastomotic leak, nodes retrieved, involved distal margin, 5-year overall survival, and locoregional recurrence. Operative blood loss was less with laparoscopic surgery compared with open, and with robotic surgery compared with open and laparoscopic. Robotic operative time was longer compared with open, laparoscopic, and transanal. Laparoscopic operative time was longer compared with open. Laparoscopic surgery resulted in lower overall postoperative morbidity and fewer wound infections compared with open. Robotic surgery had fewer wound infections compared with open. Time to defecation was longer with open surgery compared with laparoscopic and robotic. Hospital stay was longer after open surgery compared with laparoscopic and robotic, and after laparoscopic surgery compared with robotic. Laparoscopic surgery resulted in more incomplete or nearly complete mesorectal excisions compared with open, and in more involved circumferential resection margins compared with transanal. Robotic surgery resulted in longer distal resection margins compared with open, laparoscopic, and transanal. CONCLUSIONS: The different techniques result in comparable perioperative morbidity and long-term survival. The laparoscopic and robotic approaches may improve postoperative recovery, and the open and transanal approaches may improve oncological resection. Technique selection should be based on expected benefits by individual patient.

Primary Tumor Resection in Patients with Incurable Localized or Metastatic Colorectal Cancer: A Systematic Review and Meta-analysis.

BACKGROUND: To assess the impact of primary tumor resection (PTR) on survival and morbidity in incurable colorectal cancer. METHODS: Systematic literature review and meta-analysis to compare PTR versus primary tumor intact (PTI). RESULTS: Seventy-seven studies were included, reporting on 159,991 participants (94,745 PTR; 65,246 PTI). PTR improved overall survival (hazard ratio [HR] 0.59, P < 0.0001; mean difference [MD] 7.27 months, P < 0.0001), cancer-specific survival (HR 0.47, MD 10.80), and progression-free survival (HR 0.76, MD 1.67). Overall survival remained significantly improved during subgroup analysis of asymptomatic patients (HR 0.69, MD 3.86), elderly patients (HR 0.46, MD 7.71), patients diagnosed after 2000 (HR 0.62, MD 7.29), patients with colon (HR 0.58, MD 6.31) or rectal (HR 0.54, MD 6.88) primary tumor, patients undergoing resection of primary tumor versus non-resectional surgery (NRS) to treat primary tumor complications (HR 0.56, MD 8.72), and of studies with propensity score analysis (HR 0.65, MD 5.68). Overall survival per treatment strategy was: [PTI/chemotherapy] 14.30 months, [PTI/bevacizumab] 17.27 months, [PTR/chemotherapy] 21.52 months, [PTR/bevacizumab] 27.52 months. PTR resulted in 4.5% perioperative mortality and 22.4% morbidity (major adverse events 10.2%, minor 18.5%, reoperation 2.5%, intraabdominal collection/sepsis 2.2%). PTI had 21.7% morbidity (obstruction 14.4%, anemia 11.0%, hemorrhage 1.5%, perforation 0.6%, adverse events requiring surgery 15.8%). NRS resulted in 10.6% perioperative mortality and 21.7% morbidity (major 7.9%, minor 21.7%, reoperation 0.1%). CONCLUSIONS: PTR in patients with incurable colorectal cancer results in a limited improvement of survival without a significant increase in morbidity. PTR should be considered by the multidisciplinary team on an individual patient basis.

A systematic review of the literature reporting on randomised controlled trials comparing treatments for faecal incontinence in adults.

AIM: To perform a review of the literature reporting on randomised controlled trials (RCTs) comparing treatments for faecal incontinence (FI) in adults. METHODS: A literature search of MEDLINE, Embase, Science Citation Index Expanded and Cochrane was performed in order to identify RCTs reporting on treatments for FI. RESULTS: The review included 60 RCTs reporting on 4838 patients with a mean age ranging from 36.8 to 88 years. From the included RCTs, 32 did not identify a significant difference between the treatments compared. Contradictory results were identified in RCTs comparing percutaneous posterior tibial nerve stimulation and transcutaneous tibial nerve stimulation versus sham stimulation, biofeedback-pelvic floor muscle training (BF-PFMT) versus PFMT, and between bulking agents such as PTQTM versus Durasphere®. In two separate RCTs, combination treatment of amplitude-modulated medium frequency stimulation and electromyography-biofeedback (EMG-BF), was noted to be superior to EMG-BF and low-frequency electrical stimulation alone. Combination of non-surgical treatments such as BF with sphincteroplasty significantly improved continence scores compared to sphincteroplasty alone. Surgical treatments were associated with higher rates of serious adverse events compared to non-surgical interventions. CONCLUSIONS: The current evidence has not identified significant differences between treatments for FI, and where differences were identified, the results were contradictory between RCTs.

Sacral nerve stimulation versus percutaneous tibial nerve stimulation for faecal incontinence: a systematic review and meta-analysis.

AIMS: Percutaneous tibial nerve stimulation (PTNS) and sacral nerve stimulation (SNS) are both second-line treatments for faecal incontinence (FI). To compare the clinical outcomes and effectiveness of SNS versus PTNS for treating FI in adults. METHOD: A literature search of MEDLINE, Embase, Science Citation Index Expanded and Cochrane was performed in order to identify studies comparing SNS and PTNS for treating FI. A risk of bias assessment was performed using The Cochrane Collaboration's risk of bias tool. A random effects model was used for the meta-analysis. RESULTS: Four studies (one randomised controlled trial and three nonrandomised prospective studies) reported on 302 patients: 109 underwent SNS and 193 underwent PTNS. All included studies noted an improvement in symptoms after treatment, without any significant difference in efficacy between SNS and PTNS. Meta-analysis demonstrated that the Wexner score improved significantly with SNS compared to PTNS (weighted mean difference 2.27; 95% confidence interval 3.42, 1.12; P < 0.01). Moreover, SNS was also associated with a significant reduction in FI episodes per week and a greater improvement in the Fecal Incontinence Quality of Life coping and depression domains, compared to PTNS on short-term follow-up. Only two studies reported on adverse events, reporting no serious adverse events with neither SNS nor PTNS. CONCLUSION: Current evidence suggests that SNS results in significantly improved functional outcomes and quality of life compared to PTNS. No serious adverse events were identified with either treatment. Further, high-quality, multi-centre randomised controlled trials with standardised outcome measures and long-term follow-up are required in this field.

A meta-analysis comparing the risk of metastases in patients with rectal cancer and MRI-detected extramural vascular invasion (mrEMVI) vs mrEMVI-negative cases.

BACKGROUND: Pathological extramural vascular invasion (EMVI) is an independent prognostic factor in rectal cancer, but can also be identified on MRI-detected extramural vascular invasion (mrEMVI). We perform a meta-analysis to determine the risk of metastatic disease at presentation and after surgery in mrEMVI-positive patients compared with negative tumours. METHODS: Electronic databases were searched from January 1980 to March 2016. Conventional meta-analytical techniques were used to provide a summative outcome. Quality assessment of the studies was performed. RESULTS: Six articles reported on mrEMVI in 1262 patients. There were 403 patients in the mrEMVI-positive group and 859 patients in the mrEMVI-negative group. The combined prevalence of mrEMVI-positive tumours was 0.346(range=0.198-0.574). Patients with mrEMVI-positive tumours presented more frequently with metastases compared to mrEMVI-negative tumours (fixed effects model: odds ratio (OR)=5.68, 95% confidence interval (CI) (3.75, 8.61), z=8.21, df=2, P<0.001). Patients who were mrEMVI-positive developed metastases more frequently during follow-up (random effects model: OR=3.91, 95% CI (2.61, 5.86), z=6.63, df=5, P<0.001). CONCLUSIONS: MRI-detected extramural vascular invasion is prevalent in one-third of patients with rectal cancer. MRI-detected extramural vascular invasion is a poor prognostic factor as evidenced by the five-fold increased rate of synchronous metastases, and almost four-fold ongoing risk of developing metastases in follow-up after surgery.

A Systematic Review to Assess Resection Margin Status After Abdominoperineal Excision and Pelvic Exenteration for Rectal Cancer.

OBJECTIVE: The aim of this study was to assess resection margin status and its impact on survival after abdominoperineal excision and pelvic exenteration for primary or recurrent rectal cancer. SUMMARY OF BACKGROUND DATA: Resection margin is important to guide therapy and to evaluate patient prognosis. METHODS: A meta-analysis was performed to assess the impact of resection margin status on survival, and a regression analysis to analyze positive resection margin rates reported in the literature. RESULTS: The analysis included 111 studies reporting on 19,607 participants after abdominoperineal excision, and 30 studies reporting on 1326 participants after pelvic exenteration. The positive resection margin rates for abdominoperineal excision were 14.7% and 24.0% for pelvic exenteration. The overall survival and disease-free survival rates were significantly worse for patients with positive compared with negative resection margins after abdominoperineal excision [hazard ratio (HR) 2.64, P < 0.01; HR 3.70, P < 0.01, respectively] and after pelvic exenteration (HR 2.23, P < 0.01; HR 2.93, P < 0.01, respectively). For patients undergoing abdominoperineal excision with positive resection margins, the reported tumor sites were 57% anterior, 15% posterior, 10% left or right lateral, 8% circumferential, 10% unspecified. A significant decrease in positive resection margin rates was identified over time for abdominoperineal excision. Although positive resection margin rates did not significantly change with the size of the study, some small size studies reported higher than expected positive resection margin rates. CONCLUSIONS: Resection margin status influences survival and a multidisciplinary approach in experienced centers may result in reduced positive resection margins. For advanced anterior rectal cancer, posterior pelvic exenteration instead of abdominoperineal excision may improve resection margins.

Evaluation of sexual dysfunction in female patients presenting with faecal incontinence or defecation disorder.

PURPOSE: Female patients with pelvic floor diseases may suffer from several sexual disorders and sexual life impairments. The aim of this manuscript was to evaluate sexual dysfunction in female patients presenting with faecal incontinence (FI) and defecation disorder (DD). METHODS: A retrospective review was performed of a prospectively collected database of sexually active women referred to the pelvic floor clinic, who completed the Pelvic Organ Prolapse/Incontinence Sexual Questionnaire-12 (PISQ-12) at first visit. Statistical analysis was performed to evaluate and compare sexual dysfunction between patients with FI and DD and with published data on the general population. Regression analysis was used to identify predictors of sexual dysfunction and surgery. RESULTS: Three hundred thirteen patients were included, 192 (61%) with FI and 121 (39%) with DD. The patients with DD received more non-gynaecological surgical procedures (p = 0.023). More patients with DD received surgery for their current pelvic floor disease (p < 0.001). Major sexual impairment (PISQ-12 < 30) was found in 100 patients (31.9%). The mean PISQ-12 (33.2 ± 7.2) score was by 5 points lower than those reported in the general population from PISQ-validating studies. Prior anorectal surgery (odds ratio (OR) = 15.4), partner ejaculation problems (PISQ item 11, OR = 2.5), reduced sexual arousal (item 2, OR = 2.1), and orgasm perception (item 13, OR = 2.1) were the strongest predictors of worse sexual function in patients with FI. Patients with DD were almost 15 times more likely to receive subsequent surgery (OR = 14.6, p < 0.001), whereas fear of urine leakage almost doubled the risk. CONCLUSIONS: Sexual dysfunction is prevalent among patients suffering from FI and DD, and questionnaires are useful in recognizing these patients. Subsequent surgery is more common for patients with DD compared to those with FI.

Functional and quality of life outcomes following obstetric anal sphincter injury (OASI): does the grade of injury affect outcomes?

INTRODUCTION AND HYPOTHESIS: The aim of this study was to compare functional and quality of life data in patients with increasing grades of obstetric anal sphincter injury (OASI) presenting to a tertiary colorectal pelvic floor clinic within 24 months of delivery. METHODS: Prospective data were collected from the patients for the period 2009-2016 and included data on functional outcomes and motor anorectal manometry parameters. The instruments used for the evaluation of functional outcomes were the Birmingham Bowel and Urinary Symptoms Questionnaire, the Wexner Incontinence Score, Short Form 36, and the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire. OASI grade of injury was based on the postdelivery endoanal ultrasound scan. Data from patients with a grade 3a, 3b, 3c or 4 OASI were compared using one-way ANOVA for parametric data and the Kruskal-Wallis test for nonparametric data overall and for separate time periods (3-6 months, 6-12 months, 12-24 months). RESULTS: Functional patient data were available in 177 patients: 29 with grade 3a, 55 with grade 3b, 77 with grade 3c and 16 with grade 4 OASI. There was no discernible trend in worsening function with increasing severity of OASI overall, nor for the specified time periods of 3-6 months 58 patients), 6-12 months (85 patients) or 12-24 months (18 patients). CONCLUSIONS: Our series demonstrated no significant differences in functional outcomes or quality of life in patients with different OASI grades. Longer-term follow-up is required to ascertain any later functional differences which may become apparent with time.

Diagnostic accuracy of anorectal manometry for fecal incontinence: a meta-analysis.

BACKGROUND: Anorectal manometry (ARM) is conventionally used to assess patients with fecal incontinence (FI). This review aims to establish the diagnostic accuracy of ARM for FI. METHOD: A search of MEDLINE, EMBASE, Science Citation Index Expanded and Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library was performed. Studies examining the sensitivity and specificity of ARM measures, either individually or combined, in the diagnosis of FI, were included. Data analysis was conducted using the bivariate statistical method. RESULTS: Seven studies were included out of an initial search of 1499 studies. The summary sensitivity and specificity for ARM as an overall test were 0.80 (95% confidence interval (CI): 0.69-0.88) and 0.80 (95% CI: 0.65-0.90), respectively. The diagnostic odds ratio (DOR) for ARM was found to be 16.61 (95% CI: 5.52-50.03). The positive likelihood ratio (PLR) and negative likelihood ratio (NLR) for ARM were found to be 4.09 (95% CI: 2.11-7.94) and 0.25 (95% CI: 0.14-0.42), respectively. Subgroup analysis based on four studies reporting on maximum resting pressure (MRP) demonstrated a sensitivity, specificity, DOR, PLR and NLR of 0.60 (95% CI: 0.38-0.79), 0.93 (95% CI: 0.80-0.97), 20.0 (95% CI: 4.00-91.00), 8.60 (95% CI: 3.00-24.30) and 0.43 (95% CI: 0.24-0.76), respectively. CONCLUSION: ARM has been shown to be an accurate test for diagnosing FI. Further studies are required to establish the diagnostic accuracy of individual ARM measures.

A comparative study of short-term outcomes of colorectal cancer surgery in the elderly population.

BACKGROUND: Colorectal Cancer (CRC) is a disease of the elderly, and with an ageing population, oncological surgical procedures for CRC in the elderly is expected to increase. However, the balance between surgical benefits and risks associated with age and comorbidities in elderly patients is obscure. MATERIALS AND METHODS: A retrospective database of consecutive patients who received CRC surgery was used to compare short-term surgical and oncological outcomes between patients aged ≥75 and <75 years old undergoing CRC resection. RESULTS: There were 54 patients (63.5%) in the <75 group and 31 patients (36.5%) in the ≥75 group. Overall, there were no differences between the <75 and ≥75 groups in postoperative HDU/ITU stay, median hospital LOS or 30-day mortality rates. Patients ≥75 had a higher preoperative performance status (25.9% versus 71.0%, p < .001), but no difference in ASA Grade and referral pattern, proportion of emergency operations, cancer staging, resection margins, achievement of curative resection or median lymph node yield. There was a significantly higher use of adjuvant chemotherapy in the <75 age group (48.1% versus 25.8%, p = .043). CONCLUSIONS: With adequate patient selection, CRC resection in elderly patients is not associated with higher postoperative mortality or worse short-term oncological benefits.

A Systematic Review Assessing Medical Treatment for Rectovaginal and Enterovesical Fistulae in Crohn's Disease.

BACKGROUND: Rectovaginal and enterovesical fistulae are difficult to treat in patients with Crohn's disease. Currently, there is no consensus regarding their appropriate management. AIM OF THE STUDY: The aim of the study was to review the literature on the medical management of rectovaginal and enterovesical fistulae in Crohn's disease and to assess their response to treatment. METHOD: A literature search of MEDLINE, EMBASE, Science Citation Index Expanded, and Cochrane was performed. RESULTS: Twenty-three studies were identified, reporting on 137 rectovaginal and 44 enterovesical fistulae. The overall response rates of rectovaginal fistulae to medical therapy were: 38.3% complete response (fistula closure), 22.3% partial response, and 39.4% no response. For enterovesical fistulae the response rates to medical therapy were: 65.9% complete response, 20.5% partial response, and 13.6% no response. Specifically, response to anti-tumor necrosis factor therapy of 78 rectovaginal fistulae was: 41.0% complete response, 21.8% partial response, and 37.2% no response. Response of 14 enterovesical fistulae to anti-tumor necrosis factor therapy was: 57.1% complete response, 35.7% partial response, and 7.1% no response. The response to a combination of medical and surgical therapy in 43 rectovaginal fistulae was: 44.2% complete response, 20.9% partial response, and 34.9% no response. CONCLUSIONS: Medical therapy, alone or in combination with surgery, appears to benefit some patients with rectovaginal or enterovesical fistula. However, given the small size and low quality of the published studies, it is still difficult to draw conclusions regarding treatment. Larger, better quality studies are required to assess response to medical treatment and evaluate indications for surgery.

Methods to decrease blood loss during liver resection: a network meta-analysis.

BACKGROUND: Liver resection is a major surgery with significant mortality and morbidity. Specialists have tested various methods in attempts to limit blood loss, transfusion requirements, and morbidity during elective liver resection. These methods include different approaches (anterior versus conventional approach), use of autologous blood donation, cardiopulmonary interventions such as hypoventilation, low central venous pressure, different methods of parenchymal transection, different methods of management of the raw surface of the liver, different methods of vascular occlusion, and different pharmacological interventions. A surgeon typically uses only one of the methods from each of these seven categories. The optimal method to decrease blood loss and transfusion requirements in people undergoing liver resection is unknown. OBJECTIVES: To assess the effects of different interventions for decreasing blood loss and blood transfusion requirements during elective liver resection. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Science Citation Index Expanded to September 2015 to identify randomised clinical trials. We also searched trial registers and handsearched the references lists of identified trials. SELECTION CRITERIA: We included only randomised clinical trials (irrespective of language, blinding, or publication status) comparing different methods of decreasing blood loss and blood transfusion requirements in people undergoing liver resection. DATA COLLECTION AND ANALYSIS: Two review authors independently identified trials and collected data. We assessed the risk of bias using Cochrane domains. We conducted a Bayesian network meta-analysis using the Markov chain Monte Carlo method in WinBUGS 1.4, following the guidelines of the National Institute for Health and Care Excellence Decision Support Unit guidance documents. We calculated the odds ratios (OR) with 95% credible intervals (CrI) for the binary outcomes, mean differences (MD) with 95% CrI for continuous outcomes, and rate ratios with 95% CrI for count outcomes, using a fixed-effect model or random-effects model according to model-fit. We assessed the evidence with GRADE. MAIN RESULTS: We identified 67 randomised clinical trials involving a total of 6197 participants. All the trials were at high risk of bias. A total of 5771 participants from 64 trials provided data for one or more outcomes included in this review. There was no evidence of differences in most of the comparisons, and where there was, these differences were in single trials, mostly of small sample size. We summarise only the evidence that was available in more than one trial below. Of the primary outcomes, the only one with evidence of a difference from more than one trial under the pair-wise comparison was in the number of adverse events (complications), which was higher with radiofrequency dissecting sealer than with the clamp-crush method (rate ratio 1.85, 95% CrI 1.07 to 3.26; 250 participants; 3 studies; very low-quality evidence). Among the secondary outcomes, the only differences we found from more than one trial under the pair-wise comparison were the following: blood transfusion (proportion) was higher in the low central venous pressure group than in the acute normovolemic haemodilution plus low central venous pressure group (OR 3.19, 95% CrI 1.56 to 6.95; 208 participants; 2 studies; low-quality evidence); blood transfusion quantity (red blood cells) was lower in the fibrin sealant group than in the control (MD -0.53 units, 95% CrI -1.00 to -0.07; 122 participants; 2; very low-quality evidence); blood transfusion quantity (fresh frozen plasma) was higher in the oxidised cellulose group than in the fibrin sealant group (MD 0.53 units, 95% CrI 0.36 to 0.71; 80 participants; 2 studies; very low-quality evidence); blood loss (MD -0.34 L, 95% CrI -0.46 to -0.22; 237 participants; 4 studies; very low-quality evidence), total hospital stay (MD -2.42 days, 95% CrI -3.91 to -0.94; 197 participants; 3 studies; very low-quality evidence), and operating time (MD -15.32 minutes, 95% CrI -29.03 to -1.69; 192 participants; 4 studies; very low-quality evidence) were lower with low central venous pressure than with control. For the other comparisons, the evidence for difference was either based on single small trials or there was no evidence of differences. None of the trials reported health-related quality of life or time needed to return to work. AUTHORS' CONCLUSIONS: Paucity of data meant that we could not assess transitivity assumptions and inconsistency for most analyses. When direct and indirect comparisons were available, network meta-analysis provided additional effect estimates for comparisons where there were no direct comparisons. However, the paucity of data decreases the confidence in the results of the network meta-analysis. Low-quality evidence suggests that liver resection using a radiofrequency dissecting sealer may be associated with more adverse events than with the clamp-crush method. Low-quality evidence also suggests that the proportion of people requiring a blood transfusion is higher with low central venous pressure than with acute normovolemic haemodilution plus low central venous pressure; very low-quality evidence suggests that blood transfusion quantity (red blood cells) was lower with fibrin sealant than control; blood transfusion quantity (fresh frozen plasma) was higher with oxidised cellulose than with fibrin sealant; and blood loss, total hospital stay, and operating time were lower with low central venous pressure than with control. There is no evidence to suggest that using special equipment for liver resection is of any benefit in decreasing the mortality, morbidity, or blood transfusion requirements (very low-quality evidence). Radiofrequency dissecting sealer should not be used outside the clinical trial setting since there is low-quality evidence for increased harm without any evidence of benefits. In addition, it should be noted that the sample size was small and the credible intervals were wide, and we cannot rule out considerable benefit or harm with a specific method of liver resection.