Components separation technique utilizing an intraperitoneal biologic and an onlay lightweight polypropylene mesh: "a sandwich technique".

PURPOSE: Reconstruction of large, complex abdominal wall hernias is an ongoing challenge. Primary closure of such hernias is often not possible. The components separation technique (CST) is a practical option, however, recurrence rates remain unacceptably high. In an attempt to reduce recurrences, we added a biologic underlay mesh and a lightweight polypropylene onlay mesh to the traditional CST. METHODS: Patients with a large hernia defect with or without multiple recurrences were selected to undergo a CST augmented with an acellular porcine dermal collagen mesh underlay. Following midline abdominal closure, a lightweight, large-pore polypropylene onlay mesh was fixed to the abdominal fascia. The skin and subcutaneous layers were closed over two sump drains and two closed suction drains. RESULTS: Fifty-one patients underwent a mesh-reinforced CST from May 2006 to June 2010. The study population averaged 57.9 ± 1.5 years of age with 24 males and 27 females, BMI of 34.3 ± 0.9 kg/m(2), ASA score of 2.62 ± 0.08, 29 % were smokers, 29 % were diabetic, and 69 % had at least one previous abdominal wall hernia repair. Operative time averaged 196.5 ± 7.2 min with a blood loss of 318 ± 24 mL, and average hernia defect size of 301 ± 31 cm(2). Length of follow-up averaged 20.6 ± 2.1 months; surgical site occurrences were identified in 39 %, most commonly from skin necrosis. Hernia recurrence rate was 3.9 %. CONCLUSIONS: Repair of large, complex abdominal wall hernias by CST augmented with a biologic underlay mesh and a lightweight polypropylene onlay mesh results in lower recurrence rates compared to historical reports of CST alone.

The value of visual evoked potential as a screening test in neurofibromatosis.

Pattern reversal visual evoked potential (VEP) test was performed in 30 asymptomatic patients with neurofibromatosis (NF). All patients had normal visual acuity, visual fields, and ophthalmoscopic examination results. Pattern reversal VEP was abnormal in eight patients (26%). Seven of these patients had computed tomographic scans with reformated orbital views. Orbital computed tomographic scans were abnormal in six patients and in each case showed enlargement of the optic nerve on the side of VEP abnormality. Our data indicate that pattern reversal VEP is a valuable screening test in asymptomatic patients with NF. Because of the high incidence of VEP abnormality in such patients, VEP abnormality must be interpreted cautiously when a patient with NF is suspected of having other diseases or disorders that potentially affect the visual pathways.

Induction of cytotoxic lymphocytes directed against public alloantigens.

The response of H-2k lymphocytes to in vitro stimulation by H-2b and HI2d spleen cells has been monitored for the production of cytotoxic lymphocytes (CL). Using cells from H-2b strains CL which were capable of lysing both H-2b and H-2d target cells (TC) were generated. These results, together with competitive inhibitor studies of the cytotoxic activity against H-2d TC, demonstrated that T lymphocytes can respond to both public and private alloantigens of the H-2 complex. When H-2d cells were used for stimulation two of the three strains tested induced CL with cytotoxic activity towards both H-2d and H-2b TC. These observations indicate that the T cell response to alloantigen, leading to the production of cytotoxic lymphocytes, can be multicomponent like the established B cell response and can be expected to be subject to as much phenotypic variation. The full complexity may only be revealed by examing a number of combinations of stimulating strains, methods of stimulation and different kinds of target cells.