Machine learning improves prediction of postoperative outcomes after gastrointestinal surgery: a systematic review and meta-analysis

BACKGROUND

Machine learning (ML) approaches have become increasingly popular in predicting surgical outcomes. However, it is unknown whether they are superior to traditional statistical methods such as logistic regression (LR). This study aimed to perform a systematic review and meta-analysis to compare the performance of ML vs LR models in predicting postoperative outcomes for patients undergoing gastrointestinal (GI) surgery.

METHODS

A systematic search of Embase, MEDLINE, Cochrane, Web of Science, and Google Scholar was performed through December 2022. The primary outcome was the discriminatory performance of ML vs LR models as measured by the area under the receiver operating characteristic curve (AUC). A meta-analysis was then performed using a random effects model.

RESULTS

A total of 62 LR models and 143 ML models were included across 38 studies. On average, the best-performing ML models had a significantly higher AUC than the LR models (ΔAUC, 0.07; 95% CI, 0.04-0.09; P < .001). Similarly, on average, the best-performing ML models had a significantly higher logit (AUC) than the LR models (Δlogit [AUC], 0.41; 95% CI, 0.23-0.58; P < .001). Approximately half of studies (44%) were found to have a low risk of bias. Upon a subset analysis of only low-risk studies, the difference in logit (AUC) remained significant (ML vs LR, Δlogit [AUC], 0.40; 95% CI, 0.14-0.66; P = .009).

CONCLUSION

We found a significant improvement in discriminatory ability when using ML over LR algorithms in predicting postoperative outcomes for patients undergoing GI surgery. Subsequent efforts should establish standardized protocols for both developing and reporting studies using ML models and explore the practical implementation of these models.

Development and Validation of Prediction Models and Risk Calculators for Posthepatectomy Liver Failure and Postoperative Complications Using a Diverse International Cohort of Major Hepatectomies

OBJECTIVE

The study aim was to develop and validate models to predict clinically significant posthepatectomy liver failure (PHLF) and serious complications [a Comprehensive Complication Index (CCI)>40] using preoperative and intraoperative variables.

BACKGROUND

PHLF is a serious complication after major hepatectomy but does not comprehensively capture a patient's postoperative course. Adding the CCI as an additional metric can account for complications unrelated to liver function.

METHODS

The cohort included adult patients who underwent major hepatectomies at 12 international centers (2010-2020). After splitting the data into training and validation sets (70:30), models for PHLF and a CCI>40 were fit using logistic regression with a lasso penalty on the training cohort. The models were then evaluated on the validation data set.

RESULTS

Among 2192 patients, 185 (8.4%) had clinically significant PHLF and 160 (7.3%) had a CCI>40. The PHLF model had an area under the curve (AUC) of 0.80, calibration slope of 0.95, and calibration-in-the-large of -0.09, while the CCI model had an AUC of 0.76, calibration slope of 0.88, and calibration-in-the-large of 0.02. When the models were provided only preoperative variables to predict PHLF and a CCI>40, this resulted in similar AUCs of 0.78 and 0.71, respectively. Both models were used to build 2 risk calculators with the option to include or exclude intraoperative variables ( PHLF Risk Calculator; CCI>40 Risk Calculator ).

CONCLUSIONS

Using an international cohort of major hepatectomy patients, we used preoperative and intraoperative variables to develop and internally validate multivariable models to predict clinically significant PHLF and a CCI>40 with good discrimination and calibration.

Role of preoperative 3D rendering for minimally invasive parenchyma sparing liver resections

BACKGROUND

3D rendering (3DR) represents a promising approach to plan surgical strategies. The study aimed to compare the results of minimally invasive liver resections (MILS) in patients with 3DR versus conventional 2D CT-scan.

METHODS

We performed 118 3DR for various indications; the patients underwent a preoperative tri-phasic CT-scan and rendered with Synapse3D® Software. Fifty-six patients undergoing MILS with pre-operative 3DR were compared to a similar cohort of 127 patients undergoing conventional pre-operative 2D CT-scan using the propensity score matching (PSM) analysis.

RESULTS

The 3DR mandated pre-operative surgical plan variations in 33.9% cases, contraindicated surgery in 12.7%, providing a new surgical indication in 5.9% previously excluded cases. PSM identified 39 patients in both groups with comparable results in terms of conversion rates, blood loss, blood transfusions, parenchymal R1-margins, grade ≥3 Clavien-Dindo complications, 90-days mortality, and hospital stay respectively in 3DR and conventional 2D. Operative time was significantly increased in the 3DR group (402 vs. 347 min, p = 0.020). Vascular R1 resections were 25.6% vs 7.7% (p = 0.068), while the conversion rate was 0% vs 10.2% (p = 0.058), respectively, for 3DR group vs conventional 2D.

CONCLUSION

3DR may help in surgical planning increasing resectability rate while reducing conversion rates, allowing the precise identification of anatomical landmarks in minimally invasive parenchyma-preserving liver resections.

Using the Comprehensive Complication Index to Rethink the ISGLS Criteria for Post-hepatectomy Liver Failure in an International Cohort of Major Hepatectomies

OBJECTIVE

To compare different criteria for post-hepatectomy liver failure (PHLF) and evaluate the association between International Study Group of Liver Surgery (ISGLS) PHLF and the Comprehensive Complication Index (CCI)" and 90-day mortality.

SUMMARY OF BACKGROUND DATA

PHLF is a serious complication following hepatic resection. Multiple criteria have been developed to characterize PHLF.

METHODS

Adults who underwent major hepatectomies at twelve international centers (2010-2020) were included. We identified patients who met criteria for PHLF based on three definitions: 1) ISGLS, 2) Balzan (INR > 1.7 and bilirubin > 2.92mg/dL) or 3) Mullen (peak bilirubin >7mg/dL). We compared the 90-day mortality and major morbidity predicted by each definition. We then used logistic regression to determine the odds of CCI>40 and 90-day mortality associated with ISGLS grades.

RESULTS

Among 1646 included patients, 19 (1.1%) met Balzan, 68 (4.1%) met Mullen, and 444 (27.0%) met ISGLS criteria for PHLF. Of the three definitions, the ISGLS criteria best predicted 90-day mortality (AUC = 0.72; sensitivity 69.4%). Patients with ISGLS grades B&C were at increased odds of CCI > 40 (grade B OR 4.0; 95% CI: 2.2-7.2; grade C OR 137.0; 95% CI: 59.2-317.4). Patients with ISGLS grade C were at increased odds of 90-day mortality (OR 113.6; 95% CI: 55.6-232.1). Grade A was not associated with CCI> 40 or 90-day mortality.

CONCLUSIONS

In this diverse international cohort of major hepatectomies, ISGLS grade A was not associated with 90-day mortality or high CCI, calling into question the current classification of patients in this group as having clinically significant PHLF.

Effectiveness of an immersive virtual reality environment on curricular training for complex cognitive skills in liver surgery: a multicentric crossover randomized trial

BACKGROUND

Virtual reality (VR) is increasingly used in surgical education, but evidence of its benefits in complex cognitive training compared to conventional 3-dimensional (3D) visualization methods is lacking. The objective of this study is to assess the impact of 3D liver models rendered visible by VR or desktop interfaces (DIs) on residents' performance in clinical decision-making.

METHOD

From September 2020 to April 2021, a single-blinded, crossover randomized educational intervention trial was conducted at two university hospitals in Belgium and Italy. A proficiency-based stepwise curriculum for preoperative liver surgery planning was developed for general surgery residents. After completing the training, residents were randomized in one of two assessment sequences to evaluate ten real clinical scenarios.

RESULTS

Among the 50 participants, 46 (23 juniors/23 seniors) completed the training and were randomized. Forty residents (86.96%) achieved proficiency in decision-making. The accuracy of virtual surgical planning using VR was higher than that using DI in both groups A (8.43 ± 1.03 vs 6.86 ± 1.79, p < 0.001) and B (8.08 ± 0.9 vs 6.52 ± 1.37, p < 0.001).

CONCLUSION

Proficiency-based curricular training for liver surgery planning successfully resulted in the acquisition of complex cognitive skills. VR was superior to DI visualization of 3D models in decision-making.

CLINICALTRIALS

GOV ID

NCT04959630.

Key components of a hepatobiliary surgery curriculum for general surgery residents: results of the FULCRUM International Delphi consensus

BACKGROUND

In general surgery residency, hepatobiliary training varies significantly across the world. The aim of this study was to establish an international consensus among hepatobiliary surgeons on components of a hepatobiliary curriculum for general surgery residents.

METHODS

A three-round modified Delphi technique was employed. Fifty-two hepatobiliary surgeons involved in general surgery training programs were invited. An initial questionnaire was developed by a group of experts in hepatobiliary and educational research after a systematic literature review. It comprised 90 statements about knowledge, technical skills, attitudes, and postoperative care. Panelists could add or alter items. The survey was delivered electronically and the panel was instructed to score the items based on 5-point Likert scale. Consensus was reached when at least 80% of panelists agreed on a statement with Cronbach's alpha value >0.8.

RESULTS

Forty-one (79%) experts have participated. Sixteen panelists are based in Asia, 14 in Europe, and 11 in the Americas. Eighty percent of all proposed skills (81/101) were considered fundamental including knowledge (39/43), technical skills (16/32), attitude (15/15), and postoperative care (11/11).

CONCLUSION

An international consensus was achieved on components of a hepatobiliary curriculum. Acquiring broad knowledge is fundamental during residency. Advanced liver resection techniques require specialized hepatobiliary training.

Post-operative morbidity following pancreatic duct occlusion without anastomosis after pancreaticoduodenectomy: a systematic review and meta-analysis

BACKGROUND

Pancreatic duct occlusion (PDO) without anastomosis is a technique proposed to mitigate the clinical consequences of postoperative pancreatic fistulas (POPF) after pancreaticoduodenectomy. The aim of this study was to appraise the morbidity following PDO through a systematic review and meta-analysis.

METHODS

A systematic search of MEDLINE, Embase, and Web Of Science identified studies reporting outcomes of PDO following pancreaticoduodenectomy. Pooled prevalence rates of postoperative complications and mortality were computed using random-effect modeling. Meta-regression analyses were performed to examine the impact of moderators on the overall estimates.

RESULTS

Sixteen studies involving 1000 patients were included. Pooled postoperative mortality was 2.7%. A POPF was reported in 29.7% of the patients. Clinically relevant POPFs occurred in 13.5% of the patients, while intra-abdominal abscess and haemorrhages occurred in 6.7% and 5.5% of the patients, respectively. Re-operation was necessary in 7.6% of the patients. Postoperatively new onset diabetes occurred in 15.8% of patients, more frequently after the use of chemical substances for PDO (p = 0.003).

CONCLUSIONS

PDO is associated with significant morbidity including new onset of post-operative diabetes. The risk of new onset post-operative diabetes is associated with the use of chemical substance for PDO. Further evidence is needed to evaluate the potential benefits of PDO in patients at high risk of POPF.

Cancers Metastatic to the Liver

The liver is a common site of metastatic cancer spread, and metastatic lesions are the most common malignant liver tumors. Diagnosis of liver metastases often is established based on clinical assessment, laboratory tests, and appropriate imaging. Surgical resection is the treatment of choice for resectable colorectal and neuroendocrine liver metastases. Long-term survival outcome data after treatment of hepatic metastases of noncolorectal non-neuroendocrine tumors are less robust. The treatment strategy for patients with liver metastases should be determined case by case in a multidisciplinary setting.

Rectal lymphoma: report of a rare case and review of literature

Colorectal lymphoma is an extremely rare disease, representing less than 0.5% of all primary colorectal neoplasms. The disease is usually diagnosed in the advanced stages because of its primary non-specific symptoms. The most common involved site is cecum followed by rectum and ascending colon. Diffuse large B-cell lymphoma is a more frequent subtype. Although surgical resection is often technically feasible, optimal therapy for a colorectal lymphoma, especially rectal lymphoma, has not yet been identified. The authors describe a patient with the primary rectal lymphoma, high-grade features and complete response to chemotherapy.

Delayed colonic perforation following stent placement for colorectal obstruction: a description of two cases with stent palliation

Bowel stent insertion has a variety of complications one major of which is colonic perforation. The purpose of this article is to reveal two cases with delayed colonic perforation after stent placement to relieve bowel obstruction caused by rectal cancer. The first patient was a 55 year-old man who was a candidate for stent placement to avoid palliative surgery and relieve his bowel obstruction. Although the procedure resulted in complete relief of patient symptoms, but he returned with signs of peritonitis 10 days after the stent placement. A perforation was found at rectosigmoid junction on laparotomy. The second patient was a 60 year-old man who underwent a successful stent placement and returned 3 months later with a complaint of abdominal pain that showed up to be due to a rectal perforation on investigations. In conclusion, bowel perforation following stent placement can be a major complication, so close follow-up is necessary to detect it as soon as possible and prevent it from becoming an irreparable complication.

Necrotizing fasciitis of the upper extremity, case report and review of the literature

Necrotizing fasciitis is a rare, life-threatening infection most commonly seen in patients with diabetes mellitus, intravenous drug abuse, and immunocompromised conditions. The extremities are the primary sites of involvement in as many as two thirds of the cases. In a significant proportion of patients, the extremities are involved as a result of trauma, needle puncture or extravasation of drugs. The infection is usually polymicrobial. Treatment involves broad-spectrum antibiotics and multiple surgical debridements or amputation. We present a patient with necrotizing fasciitis of the upper limb and present our experience with this often lethal condition.

Management of treadmill hand injuries using soft tissue distraction

Background:

In the modern day cities, home treadmill usage is increasing. Toddlers are prone to a special injury by the treadmill, during workout the toddler tries to get on the belt and the roller action pulls the fingers under the belt and get caught between the belt and a metal rod under the machine and the belt scrapes the fingers. If untreated some of these injuries will lead to flexion contracture. The usual treatment is release of contracture and skin grafting, however, graft discoloration and recurrence of contracture are the complications of this method and the patients usually seek treatment for the brown discoloration of the grafts at a later age.

Objectives:

In this study we assess the results of Z-plasty in combination with soft tissue distraction without skin grafting with long term usage of splint as an alternative treatment for these patients.

Materials and Methods:

In this retrograde descriptive cross-sectional study, we evaluated the patients presented with treadmill hand injuries between the years 2006 and 2011. Demographic data including age and sex in addition to other information including location of trauma, severity of trauma, time elapsed between the trauma and treatment, type of treatment including wound care and surgical method and treatment outcomes were assessed.

Results:

A total of 8 patients (3 girls and 5 boys) following finger treadmill injury were assessed. 15 fingers in 7 patients had volar injury. The middle finger was the most commonly injured finger. In all patients a minimum of 2 fingers were injured and in just 1 patient 3 fingers were injured. In long-term follow-up all the patients had acceptable volar skin and complete ROM of the fingers.

Conclusions:

Due to discoloration of the skin graft and recurrence of contracture following skin graft as the sole treatment for the injury, application of Z-plasty with soft tissue distraction and long term splints seems to be a proper alternative treatment for these patients.