Relationship Between Tissue Ingrowth and Mesh Contraction

Contraction is a well-documented phenomenon occurring within two months of mesh implantation. Its etiology is unknown, but it is suggested to occur as a result of inadequate tissue ingrowth into the mesh and has been associated with hernia recurrence. In continuation of our previous studies, we compared tissue ingrowth characteristics of large patches of polyester (PE) and heavyweight polypropylene (PP) and their effect on mesh contraction. The materials used were eight PE and eight PP meshes measuring 10 × 10 cm². After random assignment to the implantation sites, the meshes were fixed to the abdominal wall fascia of swine using interrupted polypropylene sutures. A necropsy was performed three months after surgery for evaluation of mesh contraction/shrinkage. Using a tensiometer, tissue ingrowth was assessed by measuring the force necessary to detach the mesh from the fascia. Histologic analysis included inflammatory and fibroblastic reactions, scored on a 0–4 point scale. One swine developed a severe wound infection that involved two PP meshes and was therefore excluded from the study. The mean area covered by the PE meshes (87 ± 7 cm²) was significantly larger than the area covered by the PP meshes (67 ± 14 cm²) (p = 0.006). Tissue ingrowth force of the PE meshes (194 ± 37 N) had a trend toward being higher than that of the PP meshes (159 ± 43 N), although it did not reach statistical significance. There was no difference in histologic inflammatory and fibroblastic reactions between mesh types. There was a significant correlation between tissue ingrowth force and mesh size (p = 0.03, 95% CI: 0.05–0.84). Our results confirm those from previous studies in that mesh materials undergo significant contraction after suture fixation to the fascia. PE resulted in less contraction than polypropylene. A strong integration of the mesh into the tissue helps prevent this phenomenon, which is evidenced by a significant correlation between tissue ingrowth force and mesh size. Presented at the Southeastern Surgical Congress 2004 Meeting, Atlanta, GA, January 31–February 3, 2004 This study was sponsored by Promethian Surgical Devices, Boston, MA, USA.     

Does setting specific goals and providing feedback during training result in better acquisition of laparoscopic skills?

The aim of this study was to evaluate whether setting specific goals and providing feedback stimulates trainees to improve their laparoscopic skills. Two groups of eight fourth-year medical students practiced on a MIST-VR trainer, a black box laparoscopic suturing trainer, and computer-based training modules for 30 minutes, twice a week for 3 weeks. A precourse assessment of laparoscopic and open suturing skills and performance of MIST-VR tasks was obtained. Students in group A were given specific goals to achieve and were provided feedback. Group B was given no specific goals or feedback. At the end of the course, seven different tasks and skills were evaluated and subjectively scored during a laparoscopic cholecystectomy in an animal laboratory. A higher number of students in group A completed 10 or more repetitions in the MIST-VR than in group B. The groups showed no difference in final MIST-VR or overall scores in the animal laboratory. The only different scores between groups were for the use of the nondominant hand (NDH). The initial scores in the acquired cut task (ACT) in the MIST-VR correlated well with the performance in the animal laboratory. Setting goals and providing feedback tended to motivate students to practice more compared with the self-directed group. There was no difference in final MIST-VR scores or the performance in the animal laboratory, except for the NDH. The best predictor of performance was initial ACT score.     

The effects of gastric surgery on systemic ghrelin levels in the morbidly obese

HYPOTHESIS: Circulating ghrelin, produced primarily in the stomach, is a powerful orexigen. Ghrelin levels are elevated in states of hunger, but rapidly decline postprandially. Early alterations in ghrelin levels in morbidly obese patients undergoing weight reduction surgery may be attributed to gastric partitioning. DESIGN AND PATIENTS: Thirty-four patients underwent Roux-en-Y gastric bypass with a completely divided gastroplasty to create a 15-mL vertically oriented gastric pouch. Eight other patients underwent other gastric procedures that did not involve complete division of the stomach, including 4 vertical banded gastroplasties and 4 antireflux surgical procedures. Six additional patients undergoing antireflux surgery served as lean control subjects. Plasma samples were obtained before surgery and immediately after surgery. In a substudy, plasma was collected after Roux-en-Y limb formation and after dividing the stomach to identify any changes in plasma ghrelin levels. SETTING: Tertiary university medical center. MAIN OUTCOME MEASURES: Ghrelin levels at different stages of surgical intervention. RESULTS: Mean +/- SEM preoperative and postoperative ghrelin levels in the gastric bypass group were 355 +/- 20 and 246 +/- 13 pg/mL, respectively (P<.001). In the vertical banded gastroplasty group and in all patients undergoing antireflux surgery, ghrelin levels were not significantly changed. CONCLUSIONS: Compared with morbidly obese humans, lean controls had significantly higher plasma ghrelin levels at baseline. A divided gastroplasty creating a small proximal gastric pouch results in significant early declines in circulating ghrelin levels that are not observed with other gastric procedures. This may explain, in part, the loss of hunger sensation and rapid weight loss observed following gastric bypass surgery.     

DNA vaccination

Few advances in the history of vaccination have had as quick a passage (approximately 10 years) from their discovery to clinical trials and, hopefully soon, registration as DNA immunisation. A very clear picture has now emerged of the recognition of the CpG-motif rich, chimaeric bacterial DNA by dendritic cells (antigen-presenting cells [APCs]) and the subsequent activation of T lymphocytes. Both humoral and comprehensive cell-mediated responses occur in both mice and primates. No significant safety concerns have been observed following administration to several hundred human volunteers, including some children. Of special interest is the generation of strong and high avidity CD8+ cytotoxic T lymphocyte (CTL) responses in primates, following priming with chimaeric DNA and subsequent boosting with a chimaeric live viral vector, such as an attenuated poxvirus or adenovirus. The DNA may also be used as a highly potent adjuvant, inducing mainly T helper (Th)1 responses. Advantages include its potential use in the presence of antibody to the targeted infectious agent and a generally simple manufacturing process.     

Laparoscopic inguinal hernia repair

Background: Despite numerous attempts to improve the techniques used for hernia repair, current published series show that recurrence rates are as high as 5-20%. The complexity of inguinal anatomy, combined with multiple potential areas of weakness, has contributed to the difficulty in preventing recurrences. However, the laparoscopic approach to inguinal herniorrhaphy has allowed clear visualization of all preperitoneal fascial planes and anatomic landmarks, as well as the hernia defect(s) and the peritoneal reflection. In the course of our performance of a series of 1,224 laparoscopic inguinal hernia repairs, we have developed a total extraperitoneal approach that yields excellent results with a low initial recurrence rate. Herein we describe our experience. Methods: After our initial 300 transabdominal preperitoneal (TAPP) hernia repairs, which resulted in six recurrences, two bowel injuries, one bladder injury, and six cutaneous nerve injuries, the total extraperitoneal approach (TEP) was adopted. Results: The first 300 TEP repairs resulted in one recurrence, two bowel injuries, one bladder injury, and two cutaneous nerve injuries. All major complications occurred in patients who had had previous lower abdominal surgery. In the last 624 TEP herniorrhaphies we implemented some modifications to the technique, especially for patients with previous lower abdominal surgery. In this group we recorded one bladder injury, no cutaneous nerve injuries, and one recurrence. Conclusions: The total extraperitoneal approach for laparoscopic herniorrhaphy allows for a safe and effective repair with low rates of complication and recurrence. A thorough knowledge of the anatomy of the extraperitoneal space and especially the two- and three-dimensional inguinal anatomy of this space contributed greatly to the evolution of our technique.     

Laparoscopy for diagnosis and staging of malignancy.

The use of minimally invasive surgery for abdominal pathology, including malignancy, has increased significantly within the past decade. Despite the advances in radiographic imaging, the use of laparoscopy for diagnosing and staging abdominal malignancy has become an important tool in the overall care of these patients. A review of published series for a variety of abdominal malignancies is presented. With the growing experience in this technique, some preliminary conclusions and ongoing issues are discussed.     

添加谷氨酰胺的全胃肠外营养对造血干细胞移植术后常见并发症的防治作用

目的:严重的黏膜损伤是诱发造血干细胞移植后出现并发症的一常见原因,已有证据显示谷氨酰胺能降低接受化疗患儿黏膜炎的发生率。观察谷氨酰胺对异基因外周造血干细胞移植患者并发症及恢复的影响。方法:选择于2002-03/2006-11在河南省血液病研究所接受同胞异基因外周造血干细胞移植的48例血液系统肿瘤患者。所有患者及其家属对治疗和实验均知情同意,并经医院伦理委员会批准。所有患者移植前均处于完全缓解状态,营养中等或良好,心、肝、肾功能正常,将48例患者随机分为标准化全胃肠外营养液组(标准组,n=13)和加用谷氨酰胺的全胃肠外营养液组(谷氨酰胺组,n=35)。待患者中性粒细胞升至1.0×109L-1,且无任何感染指征,进行异基因外周造血干细胞移植。造血干细胞输注后第1天开始给予全胃肠外营养与胃肠外营养联合谷氨酰胺双肽,至中性粒细胞≥1.0×109L-1,且无消化道症状时停用。观察两组患者中性粒细胞恢复时间、出层流室时间以及关于感染、急性移植物抗宿主病等情况有无差异。结果:48例患者均进入结果分析。两组患者营养物质的摄入基本相同,谷氨酰胺组有6例发生黏膜炎,标准组有11例,差异显著(P<0.05);谷氨酰胺组有1例发生严重腹泻,标准组有5例,差异显著(P<0.05);谷氨酰胺组有3例发生临床感染,标准组有7例,差异显著(P<0.05);标准组中性粒细胞≥0.5×109L-1的持续时间短于谷氨酰胺组(P>0.05);谷氨酰胺组抗生素治疗时间及无菌病房居住时间较标准组短(P<0.05);两组急性移植物抗宿主病发生率差异无统计学意义(P>0.05)。结论:添加谷氨酰胺的全胃肠外营养可改善异基因造血干细胞移植患者的营养状态,减少感染及肠损害,减少急性移植物抗宿主病的发生,有利于异基因移植患者恢复。