Sean B. Orenstein

Transversus abdominis muscle release: a novel approach to posterior component separation during complex abdominal wall reconstruction.

BACKGROUND Several modifications of the classic retromuscular Stoppa technique to facilitate dissection beyond the lateral border of the rectus sheath recently were reported. We describe a novel technique of transversus abdominis muscle release (TAR) for posterior component separation during major abdominal wall reconstructions. METHODS Retrospective review of consecutive patients undergoing TAR. Briefly, the retromuscular space is developed laterally to the edge of the rectus sheath. The posterior rectus sheath is incised 0.5-1 cm underlying medial to the linea semilunaris to expose the medial edge of the transversus abdominis muscle. The muscle then is divided, allowing entrance to the space anterior to the transversalis fascia. The posterior rectus fascia then is advanced medially. The mesh is placed as a sublay and the linea alba is restored ventral to the mesh. RESULTS Between December 2006 and December 2009, we have used this technique successfully in 42 patients with massive ventral defects. Thirty-two (76.2%) patients had recurrent hernias. The average mesh size used was 1,201 ± 820 cm(2) (range, 600-2,700). Ten (23.8%) patients developed various wound complications requiring reoperation/debridement in 3 patients. At a median follow-up period of 26.1 months, there have been 2 (4.7%) recurrences. CONCLUSIONS Our novel technique for posterior component separation was associated with a low perioperative morbidity and a low recurrence rate. Overall, transversus abdominis muscle release may be an important addition to the armamentarium of surgeons undertaking major abdominal wall reconstructions.

Comparative Analysis of Histopathologic Effects of Synthetic Meshes Based on Material, Weight, and Pore Size in Mice

BACKGROUND While synthetic prosthetics have essentially become mandatory for hernia repair, mesh-induced chronic inflammation and scarring can lead to chronic pain and limited mobility. Mesh propensity to induce such adverse effects is likely related to the prosthetics material, weight, and/or pore size. We aimed to compare histopathologic responses to various synthetic meshes after short- and long-term implantations in mice. MATERIAL AND METHODS Samples of macroporous polyester (Parietex [PX]), heavyweight microporous polypropylene (Trelex[TX]), midweight microporous polypropylene (ProLite[PL]), lightweight macroporous polypropylene (Ultrapro[UP]), and expanded polytetrafluoroethylene (DualMesh[DM]) were implanted subcutaneously in mice. Four and 12 wk post-implantation, meshes were assessed for inflammation, foreign body reaction (FBR), and fibrosis. RESULTS All meshes induced varying levels of inflammatory responses. PX induced the greatest inflammatory response and marked FBR. DM induced moderate FBR and a strong fibrotic response with mesh encapsulation at 12 wk. UP and PL had the lowest FBR, however, UP induced a significant chronic inflammatory response. Although inflammation decreased slightly for TX, marked FBR was present throughout the study. Of the three polypropylene meshes, fibrosis was greatest for TX and slightly reduced for PL and UP. For UP and PL, there was limited fibrosis within each mesh pore. CONCLUSION Polyester mesh induced the greatest FBR and lasting chronic inflammatory response. Likewise, marked fibrosis and encapsulation was seen surrounding ePTFE. Heavier polypropylene meshes displayed greater early and persistent fibrosis; the reduced-weight polypropylene meshes were associated with the least amount of fibrosis. Mesh pore size was inversely proportional to bridging fibrosis. Moreover, reduced-weight polypropylene meshes demonstrated the smallest FBR throughout the study. Overall, we demonstrated that macroporous, reduced-weight polypropylene mesh exhibited the highest degree of biocompatibility at sites of mesh implantation.

Anisotropic evaluation of synthetic surgical meshes

IntroductionThe material properties of meshes used in hernia repair contribute to the overall mechanical behavior of the repair. The anisotropic potential of synthetic meshes, representing a difference in material properties (e.g., elasticity) in different material axes, is not well defined to date. Haphazard orientation of anisotropic mesh material can contribute to inconsistent surgical outcomes. We aimed to characterize and compare anisotropic properties of commonly used synthetic meshes.MethodsSix different polypropylene (Trelex®, ProLite™, Ultrapro™), polyester (Parietex™), and PTFE-based (Dualmesh®, Infinit) synthetic meshes were selected. Longitudinal and transverse axes were defined for each mesh, and samples were cut in each axis orientation. Samples underwent uniaxial tensile testing, from which the elastic modulus (E) in each axis was determined. The degree of anisotropy (λ) was calculated as a logarithmic expression of the ratio between the elastic modulus in each axis.ResultsFive of six meshes displayed significant anisotropic behavior. Ultrapro™ and Infinit exhibited approximately 12- and 20-fold differences between perpendicular axes, respectively. Trelex®, ProLite™, and Parietex™ were 2.3–2.4 times. Dualmesh® was the least anisotropic mesh, without marked difference between the axes.ConclusionAnisotropy of synthetic meshes has been underappreciated. In this study, we found striking differences between elastic properties of perpendicular axes for most commonly used synthetic meshes. Indiscriminate orientation of anisotropic mesh may adversely affect hernia repairs. Proper labeling of all implants by manufacturers should be mandatory. Understanding the specific anisotropic behavior of synthetic meshes should allow surgeons to employ rational implant orientation to maximize outcomes of hernia repair.

Ventral Hernia Management: Expert Consensus Guided by Systematic Review.

Objective: To achieve consensus on the best practices in the management of ventral hernias (VH). Background: Management patterns for VH are heterogeneous, often with little supporting evidence or correlation with existing evidence. Methods: A systematic review identified the highest level of evidence available for each topic. A panel of expert hernia-surgeons was assembled. Email questionnaires, evidence review, panel discussion, and iterative voting was performed. Consensus was when all experts agreed on a management strategy. Results: Experts agreed that complications with VH repair (VHR) increase in obese patients (grade A), current smokers (grade A), and patients with glycosylated hemoglobin (HbA1C) ≥ 6.5% (grade B). Elective VHR was not recommended for patients with BMI ≥ 50 kg/m2 (grade C), current smokers (grade A), or patients with HbA1C ≥ 8.0% (grade B). Patients with BMI= 30–50 kg/m2 or HbA1C = 6.5–8.0% require individualized interventions to reduce surgical risk (grade C, grade B). Nonoperative management was considered to have a low-risk of short-term morbidity (grade C). Mesh reinforcement was recommended for repair of hernias ≥ 2 cm (grade A). There were several areas where high-quality data were limited, and no consensus could be reached, including mesh type, component separation technique, and management of complex patients. Conclusions: Although there was consensus, supported by grade A–C evidence, on patient selection, the safety of short-term nonoperative management, and mesh reinforcement, among experts; there was limited evidence and broad variability in practice patterns in all other areas of practice. The lack of strong evidence and expert consensus on these topics has identified gaps in knowledge where there is need of further evidence.

Outcomes of Posterior Component Separation With Transversus Abdominis Muscle Release and Synthetic Mesh Sublay Reinforcement.

Objective: To evaluate the safety and efficacy of transversus abdominis muscle release (TAR) with retrorectus synthetic mesh reinforcement in a large series of complex hernia patients. Background: Posterior component separation via TAR during abdominal wall reconstruction (AWR) continues to gain popularity. Although our early experience with TAR has been promising, long-term outcomes have not been reported. Methods: From December 2006 to December 2014, consecutive patients undergoing open AWR utilizing TAR were identified in our prospectively maintained database and reviewed retrospectively. Main outcome measures included demographics, perioperative details, wound complications, and recurrences. Results: During the study period, 428 consecutive TAR procedures were analyzed. Mean age was 58, with mean body mass index 34.4 kg/m2 (range 20–65). Major comorbidities included diabetes (21%), chronic obstructive pulmonary disease (12%), and immunosuppression (3%). Mean hernia defect area was 606 cm2 (range 180–1280) and average mesh size was 1220 cm2 (range 600–4500). The majority of cases (66%) were clean, 26% were clean-contaminated, and 8% were contaminated. Eighty (18.7%) surgical-site events occurred, of which 39 (9.1%) were surgical-site infections. Three patients required mesh debridement; however, no instances of mesh explantation occurred. Of the 347 (81%) patients with at least 1-year follow-up (mean 31.5 mo), there were 13 (3.7%) recurrences. Conclusions: Complex AWR represents a formidable surgical challenge. In this large series, we demonstrated that posterior component separation via TAR with wide synthetic mesh sublay provides a very durable repair with low morbidity, even in comorbid patients with large defects. We strongly advocate TAR as a robust addition to the armamentarium of reconstructive surgeons.

In Vitro Activation of Human Peripheral Blood Mononuclear Cells Induced by Human Biologic Meshes

BACKGROUND Inflammation and wound healing play critical roles in the integration of biologic meshes (BMs) at sites of hernia repair. Monocytes/macrophages (M/MQs) are key cells involved in mesh integration. Interleukin-1beta (IL-1beta) is one of the major M/MQ-derived cytokines, and its expression is a reflection of the degree of M/MQ activation. We hypothesized that BMs induce M/MQ activation in vitro and that IL-1beta expression by M/MQ varies among various BMs. MATERIALS AND METHODS Acellular human dermis-derived BM samples (AlloDerm, AlloMax, FlexHD) were placed in 48-well plates and cultured with peripheral blood mononuclear cells (PBMCs) from three healthy human subjects for 7 d. The resulting supernatants were assayed for IL-1beta levels by enzyme-linked immunosorbent assay (ELISA), and the BMs were evaluated histologically. RESULTS IL-1beta expression varied among donors as well as the BMs [AlloDerm (2.11-38.25pg/10(6) PBMCs); AlloMax (13.12-715.40pg/10(6) PBMCs); and FlexHD (116.69-665.40pg/10(6) PBMCs)]. Analysis of this data indicated that AlloMax and FlexHD induced significantly more M/MQ activation compared with AlloDerm (P<0.05). Histologic evaluation of the BMs indicated adherence of M/MQs on BM surface, however no degradation was detected. CONCLUSION For the first time, we have demonstrated that M/MQs are activated to varying levels by human BMs in vitro. These differences may be related to BM processing technologies and/or the biologic variation between donors. Our results raise the possibility that these differences in M/MQ activation could result in varying intensity of inflammation and wound healing that control the integration of BMs at sites of hernia repair.

Effect of patient and hospital characteristics on outcomes of elective ventral hernia repair in the United States

PurposesOur ability to predict complications of ventral hernia repairs (VHR) are inadequate. Although impact of patient comorbidities and hospital characteristics on outcomes of several surgical procedures has been reported, such analysis on elective herniorrhaphy has not been performed to date. We hypothesized that obesity and diabetes as well as socioeconomic factors would have deleterious outcomes on elective VHR.MethodsAnalysis of 2004–2008 Nationwide Inpatient Sample database. Main outcome measures included wound/systemic morbidity, length of stay, discharge status, and in-hospital mortality. Bivariate and multivariate analyses were performed to assess influence of diabetes, obesity, patient socioeconomic factors, and hospital characteristics on the outcomes of VHR.ResultsA total of 78,348 adults undergoing elective VHR were analyzed. Obesity had significant risks for cardiopulmonary complications and prolonged hospitalization. Diabetics were more likely to have delayed wound healing. Hispanic patients had significantly higher rates of pulmonary complications and mortality. As compared to private insurance patients, Medicaid and Medicare patients had significantly higher odds of complications, prolonged hospitalization, non-routine discharge, and mortality.ConclusionObesity and diabetes appear to be significant predictors of morbidity in patients undergoing elective VHR. Alarmingly, Medicare/Medicaid patients not only had the highest rates of wound/systemic complications but also the highest post-operative mortality. For the first time, we demonstrated that in addition to comorbidities, both patient socioeconomic factors and hospital characteristics appear to be major determinants of post-herniorrhaphy complications and mortalities. Improved health maintenance and reduction in income-related disparities in health care delivery may be paramount in improving outcomes of VHR in the United States.

Small bowel obstruction owing to displaced spiral tack after laparoscopic TAPP inguinal hernia repair

Laparoscopic repair of inguinal hernias has become a widely accepted technique owing to its safety, efficacy, and patient satisfaction. Laparoscopic inguinal herniorrhaphies, such as the transabdominal preperitoneal (TAPP) and the totally extraperitoneal approaches, usually employ a method of fixation involving staples, titanium spiral tacks, or sutures to secure the mesh over the myopectineal orifice. The TAPP approach also requires closure of the peritoneal flap to exclude the mesh from the intraabdominal contents. Overall complication rates with TAPP are low, with small bowel obstruction incidence of 0.2% to 0.5%. This is usually attributed to inadequate peritoneal closure, trocar site herniation, or adhesions. We report a case of small bowel obstruction caused by a displaced spiral tack used for the peritoneal closure during TAPP hernia repair.

Risk factors for wound morbidity after open retromuscular (sublay) hernia repair

BACKGROUND Retrorectus repairs (RR) of abdominal wall hernias are growing in popularity, yet wound morbidity and predictors in this context have been characterized poorly. Models aimed at predicting wound morbidity typically do not control for technique and/or location of mesh. Our aim was to describe wound morbidity and risk factors specifically in the context of RR hernia repair. Our hypothesis was that the incidence of wound morbidity with mesh sublay would be less than predicted by a model that does not control for mesh position. METHODS Consecutive RR hernia repairs with at least a 90-day follow-up were identified in our prospective database and analyzed. The primary outcome measures were the incidence of surgical-site occurrence (SSO) and surgical-site infection (SSI) via modern, standardized definitions. For predictors of SSO, statistical analysis was performed with univariate analysis, χ(2), and logistic regression as well as multivariate regression. RESULTS A total of 306 patients met the inclusion criteria. Eighty-four SSOs identified in 72 (23.5%) patients included 48 (15.7%) SSIs, 14 (4.6%) instances of wound cellulitis, 12 (3.9%) skin dehiscences, 6 (2.0%) seromas, and 4 (1.3%) hematomas but no instances of mesh excision or fistula formation. Treatment entailed antibiotics alone in 30 patients, 14 bedside drainage procedures, 9 radiographically assisted drainage procedures, and 10 returns to the operating room for debridement. After multivariate analysis, diabetes (OR 2.41), hernia width >20 cm (OR 2.49), and use of biologic mesh (OR 2.93) were statistically associated with the development of a SSO (P < .05). Notably, the mere presence of contamination was not independently associated with wound morbidity (OR 1.83, P = .11). SSO and SSI rates anticipated by a recent risk prediction model were 50-80% and 17-83%, respectively, compared with our actual rates of 20-46% and 7-32%. CONCLUSION Based on a large cohort of patients, we identified factors contributing to SSOs specifically for RR hernia repairs. Paradoxically, biologic mesh was an independent predictor of wound morbidity. The development of clinically important mesh complications and rates of wound morbidity less than anticipated by recent predictive models suggest that the retromuscular (sublay) mesh position may be more advantageous.

Technical Aspects of Bile Duct Evaluation and Exploration

Choledocholithiasis is a common manifestation of biliary disease. Intraoperative cholangiography can be performed in several ways. Common bile duct exploration can be safely performed but necessitates an advanced level of surgical experience to limit complications and improve success. An algorithm based on available resources and the physician skill set is vital for safe and effective management of choledocholithiasis. Endoscopic retrograde cholangiopancreatography requires the availability of an advanced endoscopist as well as significant equipment and resources. Current training of young surgeons is limited for open biliary procedures and common bile duct explorations. Educational guidelines are necessary to reduce this educational gap.