Analysis of model development strategies: predicting ventral hernia recurrence

Research prioritization in hernia surgery: a modified Delphi ACHQC and VHOC expert consensus

PURPOSE

Numerous clinical practice guidelines and consensus statements have been published in hernia surgery, however, there is still a need for high-quality evidence to address remaining unanswered questions. The aim of this study was to conduct research priority setting through a modified Delphi process to identify a list of top research priorities in hernia surgery.

METHODS

A structured literature review of clinical practice guidelines was performed by the steering committee. Topics considered clinically significant, practical to study and lacking strong evidence were extracted and refined into a comprehensive list, then entered into a two-round Delphi survey for prioritization at the Abdominal Core Health Quality Collaborative (ACHQC) Quality Improvement Summit. In round 1, participants were instructed to select any topic that should be prioritized for future research. Topics were ranked according to the proportion of votes and the 25 highest-ranking topics were included in the second round. In round 2, participants were instructed to select only the top 10 topics for research prioritization.

RESULTS

Eleven clinical practice guidelines were reviewed. Eighty-seven topics were extracted by the steering committee and submitted for prioritization. After the first round, 25 of the highest-ranking topics were determined and included in the second round. A final list of 11 research questions was identified. The hernia types with the most research interest were inguinal and epigastric/umbilical hernias. Other topics of high interest were the management of diastasis recti, primary versus mesh repairs and expectant management versus surgical repair.

CONCLUSION

Our study provides a research agenda generated through expert consensus that may be used in the prioritization of the design and funding of clinical trials in hernia surgery.

Deep learning model utilizing clinical data alone outperforms image-based model for hernia recurrence following abdominal wall reconstruction with long-term follow up

BACKGROUND

Deep learning models (DLMs) using preoperative computed tomography (CT) imaging have shown promise in predicting outcomes following abdominal wall reconstruction (AWR), including component separation, wound complications, and pulmonary failure. This study aimed to apply these methods in predicting hernia recurrence and to evaluate if incorporating additional clinical data would improve the DLM's predictive ability.

METHODS

Patients were identified from a prospectively maintained single-institution database. Those who underwent AWR with available preoperative CTs were included, and those with < 18 months of follow up were excluded. Patients were separated into a training (80%) set and a testing (20%) set. A DLM was trained on the images only, and another DLM was trained on demographics only: age, sex, BMI, diabetes, and history of tobacco use. A mixed-value DLM incorporated data from both. The DLMs were evaluated by the area under the curve (AUC) in predicting recurrence.

RESULTS

The models evaluated data from 190 AWR patients with a 14.7% recurrence rate after an average follow up of more than 7 years (mean ± SD: 86 ± 39 months; median [Q1, Q3]: 85.4 [56.1, 113.1]). Patients had a mean age of 57.5 ± 12.3 years and were majority (65.8%) female with a BMI of 34.2 ± 7.9 kg/m2. There were 28.9% with diabetes and 16.8% with a history of tobacco use. The AUCs for the imaging DLM, clinical DLM, and combined DLM were 0.500, 0.667, and 0.604, respectively.

CONCLUSIONS

The clinical-only DLM outperformed both the image-only DLM and the mixed-value DLM in predicting recurrence. While all three models were poorly predictive of recurrence, the clinical-only DLM was the most predictive. These findings may indicate that imaging characteristics are not as useful for predicting recurrence as they have been for other AWR outcomes. Further research should focus on understanding the imaging characteristics that are identified by these DLMs and expanding the demographic information incorporated in the clinical-only DLM to further enhance the predictive ability of this model.

Laparoscopic intracorporeal rectus aponeuroplasty (LIRA) technique versus intraperitoneal onlay mesh (IPOM plus) for ventral hernia repair: a comparative analysis

PURPOSE

Primary aim of this study is to compare the postoperative outcomes of the laparoscopic intracorporeal rectus aponeuroplasty (LIRA) technique to the intraperitoneal onlay mesh closing the defect (IPOM plus), in terms of recurrence and bulging rates at one-year follow-up; secondary aim is to compare the postoperative complications, seroma and pain at 30 days and one-year after surgery.

METHODS

Patients with midline ventral hernia of 4-10 cm in width were included. Computed tomography scan was performed before, 1 and 12 months after surgery. Pain was evaluated using the visual analogue scale.

RESULTS

Forty-five and forty-seven consecutive patients underwent LIRA and IPOM plus, respectively. Preoperatively, smoke habits and chronic obstructive pulmonary disease rates were statistically significantly higher in the LIRA group (p = 0.0001 and p = 0.012, respectively). Two bulgings (4.4%) occurred in the LIRA group, while in the IPOM plus group occurred 10 bulgings (21.3%) and three recurrences (6.4%) (p = 0.017 and p = 0.085, respectively). Postoperatively, seven (15.6%, Clavien-Dindo I) and four complications (8.5%, two Clavien-Dindo I, two Clavien-Dindo III-b) occurred in the LIRA and in the IPOM plus group, respectively (p = 0.298). One month after surgery, clinical seroma, occurred in five (11.1%) and eight patients (17%) in the LIRA and in the IPOM plus group, respectively (p = 0.416). During follow-up, pain reduction occurred, without statistically significant differences.

CONCLUSIONS

In this study, even if we analysed a small series, LIRA showed lower bulging and recurrence rates in comparison to IPOM plus at one-year follow-up. Further prospective studies, with a large sample of patients and longer follow-up are required to draw definitive conclusions.

Primary closure of the midline abdominal wall defect during laparoscopic ventral hernia repair: analysis of risk factors for failure and outcomes at 5 years follow-up

BACKGROUND

The primary aim of this prospective study is to report bulging and recurrence rates and to analyze the risk factors responsible for failure, after laparoscopic ventral hernia repair (LVHR) with primary closure of defect (PCD) using a running suture and intraperitoneal mesh placement, at 5-year follow-up. The secondary endpoint is to evaluate 30-day postoperative complications, seroma, and pain.

METHODS

PCD failure was defined as the presence of postoperative bulging and/or recurrence. Pain was evaluated using a visual analogue scale (VAS). After surgery, fifty-eight patients underwent clinical examination and computed tomography scan to diagnose bulging, recurrence, and seroma (classified according to the Morales-Conde classification).

RESULTS

At 60 months follow-up, recurrence was observed in five patients (8.6%), while bulging, not needing a surgical treatment, occurred in fifteen patients (25.9%). Chronic obstructive pulmonary disease (COPD) is the only risk factor responsible for both outcomes together, bulging and recurrences (p = 0.029), while other considered risk factors as gender, age, body mass index, diabetes, smoke habits, primary or incisional hernia and the ratio defect width/transverse abdominal axis did not achieve the statistically significance. Clinical seroma was diagnosed at one month in eight patients (13.8%). Seromas were observed at one year of follow-up. During the follow-up, pain reduction occurred.

CONCLUSION

LVHR has evolved toward more anatomical concepts, with the current trend being the abdominal wall anatomical reconstruction to improve its functionality, reducing seroma rates. Based on results obtained, PCD is a reliable technique with excellent recurrence rate at 5 years follow-up, even when the defect closure may generate tension at the midline. On the other hand, this tension could be related with high bulging rate at long-term, particular in case of patients with COPD.

Identifying predictors of ventral hernia recurrence: systematic review and meta-analysis

BACKGROUND

Ventra hernias are increasing in prevalence and many recur despite attempted repair. To date, much of the literature is underpowered and divergent. As a result there is limited high quality evidence to inform surgeons succinctly which perioperative variables influence postoperative recurrence. This systematic review aimed to identify predictors of ventral hernia recurrence.

METHODS

PubMed was searched for studies reporting prognostic data of ventral hernia recurrence between 1 January 1995 and 1 January 2018. Extracted data described hernia type (primary/incisional), definitions of recurrence, methods used to detect recurrence, duration of follow-up, and co-morbidity. Data were extracted for all potential predictors, estimates and thresholds described. Random-effects meta-analysis was used. Bias was assessed with a modified PROBAST (Prediction model Risk Of Bias ASsessment Tool).

RESULTS

Screening of 18 214 abstracts yielded 274 individual studies for inclusion. Hernia recurrence was defined in 66 studies (24.1 per cent), using 41 different unstandardized definitions. Three patient variables (female sex, age 65 years or less, and BMI greater than 25, 30, 35 or 40 kg/m2), five patient co-morbidities (smoking, diabetes, chronic obstructive pulmonary disease, ASA grade III-IV, steroid use), two hernia-related variables (incisional/primary, recurrent/primary), six intraoperative variables (biological mesh, bridged repair, open versus laparoscopic surgery, suture versus mesh repair, onlay/retrorectus, intraperitoneal/retrorectus), and six postoperative variables (any complication, surgical-site occurrence, wound infection, seroma, haematoma, wound dehiscence) were identified as significant prognostic factors for hernia recurrence.

CONCLUSION

This study summarized the current evidence base for predicting ventral hernia recurrence. Results should inform best practice and future research.

Biomechanics applied to incisional hernia repair - Considering the critical and the gained resistance towards impacts related to pressure

BACKGROUND

Incisional hernia repair is burdened with recurrence, pain and disability. The repair is usually carried out with a textile mesh fixed between the layers of the abdominal wall.

METHODS

We developed a bench test with low cyclic loading. The test uses dynamic intermittent strain resembling coughs. We applied preoperative computed tomography of the abdomen at rest and during Valsalva's maneuver to the individual patient to analyze tissue elasticity.

FINDINGS

The mesh, its placements and overlap, the type and distribution of fixation elements, the elasticity of the tissue of the individual and the closure of the abdominal defect-all aspects influence the reconstruction necessary. Each influence can be attributed to a relative numerical quantity which can be summed up into a characterizing value. The elasticity of the tissues within the abdominal wall of the individual patient can be assessed with low-dose computed tomography of the abdomen with Valsalva's maneuver. We established a procedure to integrate the results into a surgical concept. We demonstrate potential computer algorithms using non-rigid b-spline registration and artificial intelligence to further improve the evaluation process.

INTERPRETATION

The bench test yields relative values for the characterization of hernia, mesh and fixation. It can be applied to patient care using established procedures. The clinical application in the first ninety-six patients shows no recurrences and reduced pain levels after one year. The concept has been spread to other surgical groups with the same results in another fifty patients. Future efforts will make the abdominal wall reconstruction more predictable.

Development and Validation of the Ventral Hernia Repair Outcomes Reporting App for Clinician and Patient Engagement (ORACLE)

BACKGROUND

Patient engagement is an increasingly important component of surgical decision making. Given the many factors associated with successful ventral hernia repair (VHR), we developed and validated the Outcomes Reporting App for Clinical and Patient Engagement (ORACLE) tool to help facilitate preoperative surgeon-patient discussions about VHR.

METHODS

All patients undergoing elective, VHR with 30-day follow-up data available within the Americas Hernia Society Quality Collaborative were eligible for study inclusion. Using bootstrapping and bias-corrected calibration, predictive models were generated and validated for 5 quality measures after VHR, including postoperative wound events, estimated length of hospital stay, unplanned 30-day readmission to the hospital, and risk of hernia recurrence at 1 year postoperatively.

RESULTS

A total of 10,690 patients met inclusion criteria. Based on comparison of the theoretical best to the observed calibration curves, the models for each of the 5 outcomes of interest have strong predictive strength as reflected in the Brier score for surgical site infection, surgical site occurrence requiring procedural intervention, and 30-day hospital readmission, the c-index for 1-year hernia recurrence and the R² value for the model for predicted hospital length of stay.

CONCLUSIONS

Using a national data set for development, ORACLE can be used to facilitate patient engagement, with the goal of tailoring interventions for VHR given each patient's unique factors. With ongoing data input into the Americas Hernia Society Quality Collaborative and a continuous re-evaluation of these risk models, it is our intention that this tool will serve as an up-to-date resource for hernia surgeons and ventral hernia patients.