Clinical outcomes of oncologic hernia repair using poly-4-hydroxybutyrate (P4HB) mesh

Authors: Levy J, Wagner BD, Shammas RL, Boe LA, Ariyan CE, Brady MS, Allen RJ Jr, Matros E, Mehrara BJ, Nelson JA.

Affiliation: Memorial Sloan Kettering Cancer Center

Journal: Hernia, Sept. 2025

PMID: 40960565

Key takeaways

• In 102 oncologic patients, hernia recurrence was 8.8% (9/102) at median 26.1 months; 0/49 in clean vs 9/53 (17.0%) in contaminated wounds.

• Retrorectus mesh placement and bilateral external oblique release were associated with lower recurrence (HRs ≈0.05 and ≈0.16) on univariable competing-risk analysis.

• Surgical-site complications occurred in 24%; most common were seroma 8.8% and superficial dehiscence 7.8%.

Background

Oncologic patients have elevated wound and infection risks after ventral/incisional hernia repair. P4HB, a slowly resorbable mesh, may balance strength and biocompatibility in high-risk fields.

Objective

Evaluate hernia recurrence and surgical-site complications after incisional hernia repair with P4HB mesh in oncologic patients and identify surgical techniques linked to improved outcomes.

Methods

• Design/setting/LOE: Retrospective single-center cohort, 2018–2023; Level III evidence.

• Population: Adults with prior intra-abdominal/pelvic malignancy and incisional hernia undergoing hernia repair with P4HB mesh. N = 102.

• Inclusion/exclusion: Included oncologic laparotomy history + P4HB mesh repair. Excluded synthetic/biologic mesh, primary suture, bridging, prophylactic mesh at index cancer surgery.

• Techniques: Mesh placed retrorectus (Rives–Stoppa), underlay, or onlay; component separation recorded (external oblique release or transversus abdominis release).

• Wound classification: CDC wound classes I–IV recorded; outcomes also compared as clean (Class I) vs contaminated (Classes II–IV).

  • Ventral Hernia Working Group (VHWG) or European Hernia Society (EHS) hernia grades were not reported.

• Primary endpoints: Hernia recurrence and surgical-site complications (hematoma, infection/cellulitis, superficial dehiscence, abscess).

• Follow-up/assessment: Median 26.1 months (IQR 15.1–40.1); recurrence assessed by CT (88%) or exam (12%); competing-risk analysis with death as competing event.

• Statistics: Wilcoxon, χ²/Fisher; Fine–Gray competing-risk regression (univariable only; multivariable modeling not performed due to few recurrence events); α = 0.05.

Results

• Cohort characteristics: Median age 63; BMI 26; ASA III 76%; 52% contaminated fields (CDC classes: I 48%, II 43%, III 8%, IV 1%); 68% retrorectus placement; 71% bilateral external oblique release; frequent concomitant oncologic procedures.

• Recurrence: 8.8% overall; 0% in clean (Class I) vs 17.0% in contaminated (Classes II–IV); P = 0.003.

• Complications: Any 24%; seroma 8.8%, superficial dehiscence 7.8%, hematoma 6.9%, infection/cellulitis/abscess 6.9%; similar across wound classes.

• Technique associations (competing-risk models):

  • Retrorectus vs onlay: HR 0.05 (95% CI 0.01–0.34; P = 0.010).

  • Bilateral external oblique release: HR 0.16 (95% CI 0.04–0.65; P = 0.010).

Conclusion

In oncologic incisional hernia repair, P4HB mesh yielded low recurrence and acceptable complication rates; retrorectus placement and bilateral external oblique release were associated with fewer recurrences.

Strengths & limitations

• Strengths: Focused oncologic cohort; high rate of imaging-based recurrence assessment, though timing not standardized; technique-level analysis.

• Limitations: Retrospective single-center design; no multivariable adjustment (few recurrence events) → risk of residual confounding (e.g., contamination, case complexity influencing technique choice). Hernia grading (VHWG/EHS), defect size/loss-of-domain, and detailed oncologic variables (prior radiation, chemotherapy timing), smoking/diabetes were not reported or adjusted. Imaging follow-up timing was not standardized. Generalizability may be limited (high-volume cancer center, average BMI 26).

Clinical relevance

• P4HB is a reasonable mesh option in contaminated or high-risk settings, balancing strength with long-term resorption.

Critiques and notes

• Selection bias/confounding by indication: Technique choice (retrorectus plane, bilateral external oblique release) likely varied by wound cleanliness and defect complexity; without multivariable adjustment, the reported associations may reflect case selection rather than true technique effect.

• Missing anatomic/oncologic context: Key predictors (defect size, loss of domain, prior mesh explant/infection, radiation history, VHWG/EHS grade) are not reported, limiting risk adjustment and external validity.

• Follow-up adequacy: Given P4HB resorption over ~12–18 months, a median 26-month follow-up is reasonable, yet late recurrences beyond 24–36 months remain plausible.

• Outcome scope: Important endpoints—reoperation, mesh explantation, chronic pain, and patient-reported outcomes (function/quality of life)—are missing, constraining clinical interpretation.

• Comparative effectiveness: The absence of a comparator cohort (permanent synthetic or biologic mesh) or propensity-matched controls limits interpretation of the 17% recurrence observed in contaminated fields.