Charles J. Dolce

Does liver appearance predict histopathologic findings: prospective analysis of routine liver biopsies during bariatric surgery

BACKGROUND Nonalcoholic fatty liver disease is associated with morbid obesity. Liver biopsy is the reference standard for the diagnosis of nonalcoholic fatty liver disease. It is unclear whether the macroscopic liver appearance correlates with the histopathologic findings. Our objective was to determine the relationship between the intraoperative liver appearance and the histopathologic findings during laparoscopic bariatric surgery at a tertiary medical center. METHODS Data were prospectively collected from 108 consecutive patients undergoing laparoscopic bariatric surgery with routine intraoperative liver biopsy. An intraoperative liver visual score was recorded according to the size, tan-speckling, and contour. The liver histologic findings were categorized into 3 groups: (1) normal; (2) bland steatosis; and (3) nonalcoholic steatohepatitis (NASH). The liver visual score was compared with the liver histologic findings. A recorded video of the liver was regraded at a later date to determine observer agreement. RESULTS The prevalence of NASH was 23% (n = 25). Of the 108 patients, 48% with NASH had normal-appearing livers and accounted for 24% (n = 12) of the 50 normal-appearing livers. A similar proportion of NASH cases was found in all 3 visual categories. Furthermore, no relationship was found between the number of abnormal visual cues and the liver histologic findings (P = .23). No complications were directly attributable to liver biopsy. The kappa values for intraobserver and interobserver agreement ranged from fair to almost perfect. CONCLUSION NASH is common in the morbidly obese population. There does not appear to be a relationship between liver appearance and the histopathologic findings. Intraoperative liver biopsy is a safe and accurate method of diagnosing liver disease and should be considered in all morbidly obese patients undergoing abdominal surgery.

Reverse Alignment “Mirror Image” Visualization as a Laparoscopic Training Tool Improves Task Performance

Reverse alignment (mirror image) visualization is a disconcerting situation occasionally faced during laparoscopic operations. This occurs when the camera faces back at the surgeon in the opposite direction from which the surgeon’s body and instruments are facing. Most surgeons will attempt to optimize trocar and camera placement to avoid this situation. The authors’ objective was to determine whether the intentional use of reverse alignment visualization during laparoscopic training would improve performance. A standard box trainer was configured for reverse alignment, and 34 medical students and junior surgical residents were randomized to train with either forward alignment (DIRECT) or reverse alignment (MIRROR) visualization. Enrollees were tested on both modalities before and after a 4-week structured training program specific to their modality. Student’s t test was used to determine differences in task performance between the 2 groups. Twenty-one participants completed the study (10 DIRECT, 11 MIRROR). There were no significant differences in performance time between DIRECT or MIRROR participants during forward or reverse alignment initial testing. At final testing, DIRECT participants had improved times only in forward alignment performance; they demonstrated no significant improvement in reverse alignment performance. MIRROR participants had significant time improvement in both forward and reverse alignment performance at final testing. Reverse alignment imaging for laparoscopic training improves task performance for both reverse alignment and forward alignment tasks. This may be translated into improved performance in the operating room when faced with reverse alignment situations. Minimal lab training can account for drastic adaptation to this environment.

Effect of Bacterial Exposure on Acellular Human Dermis in a Rat Ventral Hernia Model

BACKGROUND Effectiveness of acellular human dermis (AHD) as an alternative to synthetic mesh in contaminated fields has been described. Cellular migration after implantation and corresponding strength of attachment is not well documented. Our aim is to correlate AHD vascularization, fibroblast migration, and strength of attachment with presence of inflammatory cells in clean and contaminated fields. MATERIALS AND METHODS Lewis rats were randomized to a control and three experimental groups. AHD was placed as an onlay over the intact abdominal wall. Experimental groups (n=72) were exposed to Staphylococcus aureus at 1 x 10(4), 1 x 10(5), or 1 x 10(6) by direct application; controls (n=12) were not exposed. At 5 and 28 d, abdominal walls were explanted and tissue ingrowth assessed via tensiometry measuring energy (E) and max stress (MS) at the AHD-tissue interface. Vascularity, fibroblast migration, and inflammatory cell migration were compared using light microscopy. RESULTS Shear strength reported as energy and max stress were significantly greater at 28 versus 5 d in all experimental groups, remaining unchanged in controls. Plasma cells and histiocytes significantly increased in all groups; macrophages increased in experimental groups only. Vascular ingrowth increased significantly in all groups; fibroblast migration was greater in controls and 1 x 10(6) exposed group only. CONCLUSIONS Contamination of AHD results in inflammatory cell influx and a surprising increase in shear strength. Interestingly, shear strength does not increase without contamination. Inflammation stimulates vascular ingrowth, but not equally significant fibroblast migration. Longer survivals are required to determine if energy and max stress of controls increase, and fibroblast migration follows vascular ingrowth.

Evaluation of Soft Tissue Attachments to a Novel Intra-abdominal Prosthetic in a Rabbit Model

Background. Laparoscopic ventral hernia repair requires placement of an intraperitoneal prosthetic. Composite mesh types have been developed to address the shortcomings of standard meshes. The authors evaluated the host reaction to intraperitoneal placement of a novel composite material. Materials and Methods. A comparison of an innovative polypropylene/polylactide composite mesh was made to Parietex Composite (PCO), Proceed, and DualMesh. Eighteen meshes per group were implanted on intact peritoneum in New Zealand White rabbits. The main outcome measures included the formation of visceral adhesions, adhesion tenacity, tensiometric measurements, and histological analysis. Evaluations of adhesions were made at 1, 4, and 16 weeks using a 2-mm minilaparoscopy. Results. There were no significant differences in the mean adhesion scores between the composite mesh types at week 1 (P = .15) and week 16 (P = .06). At 4 weeks, PCO had significantly fewer adhesions when compared with the other 3 mesh types (P = .02). Adhesion tenacity was also equivalent within the group at 16 weeks (P = .06). Tensiometry and histological analysis revealed no statistically significant differences between the mesh types. Conclusions. Four different composite mesh types had equivalent intra-abdominal soft tissue attachments in a rabbit model after a 16-week implantation period. PCO demonstrated the lowest mean adhesion score of each mesh type. Each mesh exhibited equivalent stiffness and energy to failure after explantation. The 4 composite mesh types demonstrated the successful formation of a neoperitoneum and comparable host biocompatibility as evidenced by similar degrees of inflammation.