Background:  In patients with ventral hernias, primary fascial approximation results in a 40-50% risk of recurrence.  The use of synthetic mesh has decreased recurrence rates to 20-25%, but carries its own subset of risks including infections, fistulas, and other complications often mandating implant removal.  The component separation technique (CST) provides a medial mobilization of bilateral musculocutaneous units for closure without prosthetic material and may lower hernia recurrence rates.  

Purpose:  In this retrospective study, we reviewed our series of patients at the University of Michigan, comparing complex incisional hernias repaired using the CST without a prosthesis or CST with the addition of an underlay acellular dermal allograft (AlloDerm^TM; LifeCell Corporation, Branchburg, NJ).

Methods:  After receiving Institutional Review Board approval, one hundred and fourteen patients were identified that were treated between March 2002 and November 2007.  In all patients, the surgical technique involved musculofascial release of the external oblique muscle lateral to the linea semilunaris line.  In 36 of 114 patients, a single-layer of AlloDerm^TM was implanted beneath the fascial edges of defect as an “underlay” interposition under moderate tension.  After bilateral midline advancement of musculofascial units, a tension-free midline closure was performed.  Patient demographics, preoperative risk factors, surgical indications, operative technique and details, and postoperative complications including recurrence rates were extracted from the clinical record.  Pearson Chi-Square, Fisher’s Exact Test, and Mann Whitney U Test were used for analysis using SPSS v. 15 as appropriate.

Results:  Component separation technique (CST) was performed in seventy-eight patients without a prosthesis and in thirty-six patients using reinforcement of an underlay AlloDerm^TM.  There were no statistical differences between the groups in terms of average age (52 versus 54 years), Body Mass Index (33 versus 35 kg/m²), male ratio (51% versus 44%), or history of previous surgeries (70% versus 78%).  The average size of hernia defect in each group was statistically different 322 cm² in the patients receiving CST alone versus 453 cm² in the patients receiving CST and an underlay (p = 0.02).  Postoperative complications including infection, seroma, and skin dehiscence were increased in patients repaired using CST without prosthesis compared with CST and AlloDerm^TM (p £ 0.05).  In the CST without prosthesis group compared to the CST with AlloDerm^TM group, the recurrence rate was 24% (n=19) versus 14% (n=5), but this difference did not achieve statistical significance.

Conclusions:  This study demonstrates that component separation technique with the addition of a single-layer of underlay AlloDerm^TM implant in abdominal wall reconstruction and incisional hernia repair decreases postoperative complications and suggests that the recurrence rate may be lower with an AlloDerm^TM underlay.  By optimizing tension, reinforcing and providing an adequate biocompatible prosthetic support, CST with a single-layer of underlay AlloDerm^TM should be considered for complex and recurrent hernia repair.