Faculty Bibliography

The use of mesh materials for reinforcement of the abdominal wall has revolutionized the approaches to hernia repair. Whether it's a permanent, synthetic mesh, a biologically derived collagen graft, or a synthetic, bioresorbable construct, data demonstrate improved outcomes with respect to recurrence with their use. Numerous advances and development of component separation techniques of the abdominal wall musculature have provided surgeons the ability to close large fascial defects and reestablish the linea alba for midline hernias. Augmentation of the these repairs with a mesh helps to offset the tension on the fascial closure and provide biomechanical strength to the native tissue. However, the use of mesh materials as either permanent or temporary scaffolds is not without potential complications. Abdominal wall surgeons must have knowledge of the mesh composition and structure in an effort to mitigate these concerns. This chapter will review the polymers and characteristics of the currently available synthetic meshes for abdominal wall reconstruction in an effort to provide guidance to surgeons.

BACKGROUND:Laparoscopic ventral hernia repair (LVHR) demonstrates comparable recurrence rates, but lower incidence of surgical site infection (SSI) than open repair. Delayed complications can occur with intraperitoneal mesh, particularly if a subsequent abdominal operation is required, potentially resulting in bowel injury. Robotic retromuscular ventral hernia repair (RRVHR) allows abdominal wall reconstruction (AWR) and extraperitoneal mesh placement previously only possible with open repair, with the wound morbidity of LVHR. METHODS:All LVHR and RRVHR performed in our institution between June 2013 and May 2015 contained in the Americas Hernia Society Quality Collaborative database were analyzed. Continuous bivariate analysis was performed with Student's t test. Continuous nonparametric data were compared with Chi-squared test, or Fisher's exact for small sample sizes. p values <0.05 were considered significant. RESULTS:We compared 103 LVHR with 53 RRVHR. LVHR patients were older (60.2 vs. 52.9 years; p = 0.001), but demographics were otherwise similar between groups. Hernia width was similar (6.9 vs. 6.5 cm, p = 0.508). Fascial closure was achieved more often with RRVHR (96.2 vs. 50.5 %; p < 0.001) and aided by myofascial release in 43.4 %. Mesh was placed in an intraperitoneal position in 90.3 % of LVHR and extraperitoneal in 96.2 % of RRVHR. RRVHR operative time was longer (245 vs. 122 min, p < 0.001). Narcotic requirement was similar between LVHR and RRVHR (1.8 vs. 1.4 morphine equivalents/h; p = 0.176). Seroma was more common after RRVHR (47.2 vs. 16.5 %, p < 0.001), but SSI was similar (3.8 vs. 1 %, p = 0.592). Median length of stay was shorter after RRVHR (1 vs. 2 days, p = 0.004). Direct hospital cost was similar (LVHR $13,943 vs. RRVHR $19,532; p = 0.07). CONCLUSION:RRVHR enables true AWR, with myofascial release to offset tension for midline fascial closure, and obviates the need for intraperitoneal mesh. Perioperative morbidity of RRVHR is comparable to LVHR, with shorter length of stay despite a longer operative time and extensive tissue dissection.

Parastomal hernias (PHs) cause significant morbidity in patients with permanent ostomies, and several laparoscopic and open repair techniques have been described. We report our experience with open retromuscular repair of PHs using permanent synthetic mesh. A prospectively maintained database was retrospectively reviewed to identify patients undergoing PH repair. Primary outcomes are surgical site occurrence, surgical site infection (SSI), and hernia recurrence. Variables were analyzed using Pearson's χ2 test or Fisher's exact test. Values of P < 0.05 were considered significant. Forty-six patients underwent retromuscular PH repair with permanent synthetic mesh. There were 26 patients with colostomies and 20 with ileostomies. All the patients were repaired using a keyhole retromuscular technique and direct passage of stoma through mesh. Transversus abdominis release was performed in 65.2 per cent of cases. Permanent synthetic polypropylene mesh was used in all cases. Surgical site occurrence occurred in 47.8 per cent of patients, SSI in 17.4 per cent, and hernia recurrence in 21.7 per cent. Resiting the stoma yielded the highest rate of SSI (40%) compared with leaving the stoma in situ (11.8%) or rematuring the stoma (0%; P = 0.011). Open keyhole retromuscular PH repair of PH with permanent synthetic mesh is safe, effective, and durable.

Recurrence after ventral hernia repair (VHR) remains a significant complication. We sought to identify the technical aspects of VHR associated with recurrence. Patients who underwent open midline VHR between 2006 and 2013 (n = 261) were retrospectively evaluated. Patients with recurrence (Group 1, n = 48) were compared with those without recurrence (Group 2, n = 213). Smoking, diabetes, and body mass index were not different between groups. More patients in Group 1 underwent clean-contaminated, contaminated, or dirty procedures (43.8 vs 27.7%; P = 0.021). Group 1 had a higher incidence of surgical site occurrence (52.1 vs 32.9%; P = 0.020) and surgical site infection (43.8 vs 15.5%; P < 0.001). Recurrences were due to central mesh failure (CMF) (39.6%), midline recurrence after biologic or bioabsorbable mesh repair (18.8%), superior midline (16.7%), lateral (16.7%), and after mesh explantation (12.5%). Most CMF (78.9%) occurred with light-weight polypropylene (LWPP). Recurrence was higher if the midline fascia was unable to be closed. Recurrence with midweight polypropylene (MWPP) was lower than biologic (P < 0.001), bioabsorbable (P = 0.006), and light-weight polypropylene (P = 0.046) mesh. Fixation, component separation technique, and mesh position were not different between groups. Wound complications are associated with subsequent recurrence, whereas midweight polypropylene is associated with a lower overall risk of recurrence and, specifically, CMF.

Purpose: While the tumor microenvironment has been known to play an integral role in tumor progression, the function of nonresident bone marrow-derived cells (BMDC) remains to be determined in neurologic tumors. Here we identified the contribution of BMDC recruitment in mediating malignant transformation from low- to high-grade gliomas.Experimental Design: We analyzed human blood and tumor samples from patients with low- and high-grade gliomas. A spontaneous platelet-derived growth factor (PDGF) murine glioma model (RCAS) was utilized to recapitulate human disease progression. Levels of CD11b⁺/GR1⁺ BMDCs were analyzed at discrete stages of tumor progression. Using bone marrow transplantation, we determined the unique influence of BMDCs in the transition from low- to high-grade glioma. The functional role of these BMDCs was then examined using a JAK 1/2 inhibitor (AZD1480).Results: CD11b⁺ myeloid cells were significantly increased during tumor progression in peripheral blood and tumors of glioma patients. Increases in CD11b⁺/GR1⁺ cells were observed in murine peripheral blood, bone marrow, and tumors during low-grade to high-grade transformation. Transient blockade of CD11b⁺ cell expansion using a JAK 1/2 Inhibitor (AZD1480) impaired mobilization of these cells and was associated with a reduction in tumor volume, maintenance of a low-grade tumor phenotype, and prolongation in survival.Conclusions: We demonstrate that impaired recruitment of CD11b⁺ myeloid cells with a JAK1/2 inhibitor inhibits glioma progression in vivo and prolongs survival in a murine glioma model. Clin Cancer Res; 23(12); 3109-19. ©2016 AACR.

BACKGROUND:There is limited data on enhanced recovery after surgery (ERAS) protocols after ventral hernia repair (VHR). This study reports the impact of multimodal analgesia on opioid use after open VHR. METHODS:Retrospective review of open VHR treated during the initial 6 months after ERAS implementation. Protocol focused on opioid sparing using intraoperative ketamine and/or lidocaine infusion, selective epidural anesthesia, and postoperative ketamine infusion, ketorolac, and acetaminophen. Four groups were analyzed: 1-ERAS protocol with epidural analgesia, 2-historical controls with epidural analgesia prior to ERAS, 3-ERAS protocol without epidural, and 4-historical controls without epidural analgesia, prior to ERAS. Continuous variables were analyzed using ANOVA or Kruskal-Wallis tests, and subgroup analysis using Student's t test or Mann-Whitney U test. Discrete variables were analyzed using Pearson's chi-square test or Fisher's exact test. RESULTS:Patients differed in hernia width, but were similar in comorbidity and operative technique. There was no difference in length of stay or readmission. Use of ERAS nearly eliminated patient-controlled analgesia use (group 1, 2.7%; group 2, 68.4%; group 3, 0%; group 4, 65.7%; p < 0.001). ERAS significantly reduced narcotic requirements on postoperative days 0, 1, and 2 (p < 0.001). To account for the bias of selective epidural analgesia, groups 1 and 2 (epidural) and groups 3 and 4 (no epidural) were compared separately. Opioid requirement and PCA use remained significantly lower in patients in the ERAS pathway. CONCLUSION/CONCLUSIONS:Implementation of multimodal analgesia in the perioperative and postoperative setting significantly reduced opioid use after VHR.

INTRODUCTION:Laparoscopic ventral hernia repair (LVHR) with intraperitoneal mesh placement is well established; however, the fate of patients requiring future abdominal operations is not well understood. This study identifies the characteristics of LVHR patients undergoing reoperation and the sequelae of reoperation. METHODS:A retrospective review of a prospectively maintained database at a hernia referral center identified patients who underwent LVHR between 2005 and 2014 and then underwent a subsequent abdominal operation. The outcomes of those reoperations were collected. Data are presented as a mean with ranges. RESULTS:). After a mean follow-up of 19.4 months, the overall hernia recurrence rate was 8.4 %. Subsequent abdominal operations were performed in 17 % (125 patients) at a mean 2.2 years. The most common indication for reoperation was recurrent hernia (33 patients, 26.4 %), followed by bowel obstruction (18 patients, 14.4 %), hepatopancreaticobiliary (17 patients, 13.6 %) and infected mesh removal (15 patients, 12 %), gynecologic (10 patients, 8 %), colorectal (8 patients, 6.4 %), bariatric (4 patients, 3 %), trauma (1 patient, 0.8 %), and other (19 patients, 15 %). The overall incidence of enterotomy or unplanned bowel resection (EBR) at reoperation was 4 %. This occurred exclusively in those reoperated for complete bowel obstruction, and the reason for EBR was mesh-bowel adhesions. No other indication for reoperation resulted in EBR. The incidence of secondary mesh infection after subsequent operation was 2.4 %. CONCLUSION:In a large consecutive series of LVHR, the rate of abdominal reoperation was 17 %. Generally, these reoperations can be performed safely. A reoperation for bowel obstruction, however, may carry an increased risk of EBR as a direct result of mesh-bowel adhesions. Secondary mesh infection after reoperation, although rare, may also occur. Surgeons should discuss with their patients the potential long-term implications of having an intraperitoneal mesh and how it may impact future abdominal surgery.