Experimental Strategies to Bridge Large Tissue Gaps in the Injured Spinal Cord after Acute and Chronic Lesion.

After a spinal cord injury (SCI) a scar forms in the lesion core which hinders axonal regeneration. Bridging the site of injury after an insult to the spinal cord, tumor resections, or tissue defects resulting from traumatic accidents can aid in facilitating general tissue repair as well as regenerative growth of nerve fibers into and beyond the affected area. Two experimental treatment strategies are presented: (1) implantation of a novel microconnector device into an acutely and completely transected thoracic rat spinal cord to readapt severed spinal cord tissue stumps, and (2) polyethylene glycol filling of the SCI site in chronically lesioned rats after scar resection. The chronic spinal cord lesion in this model is a complete spinal cord transection which was inflicted 5 weeks before treatment. Both methods have recently achieved very promising outcomes and promoted axonal regrowth, beneficial cellular invasion and functional improvements in rodent models of spinal cord injury. The mechanical microconnector system (mMS) is a multi-channel system composed of polymethylmethacrylate (PMMA) with an outlet tubing system to apply negative pressure to the mMS lumen thus pulling the spinal cord stumps into the honeycomb-structured holes. After its implantation into the 1 mm tissue gap the tissue is sucked into the device. Furthermore, the inner walls of the mMS are microstructured for better tissue adhesion. In the case of the chronic spinal cord injury approach, spinal cord tissue - including the scar-filled lesion area - is resected over an area of 4 mm in length. After the microsurgical scar resection the resulting cavity is filled with polyethylene glycol (PEG 600) which was found to provide an excellent substratum for cellular invasion, revascularization, axonal regeneration and even compact remyelination in vivo.

A mechanical microconnector system for restoration of tissue continuity and long-term drug application into the injured spinal cord.

Complete transection of the spinal cord leaves a gap of several mm which fills with fibrous scar tissue. Several approaches in rodent models have used tubes, foams, matrices or tissue implants to bridge this gap. Here, we describe a mechanical microconnector system (mMS) to re-adjust the retracted spinal cord stumps. The mMS is a multi-channel system of polymethylmethacrylate (PMMA), designed to fit into the spinal cord tissue gap after transection, with an outlet tubing system to apply negative pressure to the mMS thus sucking the spinal cord stumps into the honeycomb-structured holes. The stumps adhere to the microstructure of the mMS walls and remain in the mMS after removal of the vacuum. We show that the mMS preserves tissue integrity and allows axonal regrowth at 2, 5 and 19 weeks post lesion with no adverse tissue effects like in-bleeding or cyst formation. Preliminary assessment of locomotor function in the open field suggested beneficial effects of the mMS. Additional inner micro-channels enable local substance delivery into the lesion center via an attached osmotic minipump. We suggest that the mMS is a suitable device to adapt and stabilize the injured spinal cord after surgical resection of scar tissue (e.g., for chronic patients) or traumatic injuries with large tissue and bone damages.

Complications and mortality after percutaneous endoscopic gastrostomy in geriatrics: a prospective multicenter observational trial.

BACKGROUND: Generally, the high short-term mortality after percutaneous endoscopic gastrostomy (PEG) in geriatric patients is attributed to the severity of their underlying diseases. However, the procedure-related mortality in this group is unknown. METHODS: This prospective multicenter observational study gathered information about 197 geriatric patients treated with PEG insertion, including the indication for PEG insertion and the prevalence of postprocedure complications and analyzed how these factors related to mortality. RESULTS: Dysphagia (64%) and insufficient food intake (76%) were the most frequent indications for PEG insertion. Severe complications after PEG insertion occurred in 9.6% of patients. Mortality was 9.6% in hospital, as well as 18.4% at 1 month. Six months after PEG placement, with 81 patients lost to follow-up, mortality was 51.9%. Hospital mortality was significantly higher in patients with severe complications caused by PEG insertion (47.4% vs 5.6%; P < .001). A regression analysis that corrected for confounding factors revealed that severe complications in general (HR 6.9; 95% CI: 2.6-18.1; P < .001), peritonitis (HR 33.1; 95% CI: 3.7-293.2; P = .002), and severe wound infections (HR 6.9; 95% CI: 1.9-24.9; P = .003) were each independently associated with hospital mortality. Considering the prevalence of procedure-related complications and their association with early mortality after PEG insertion, the procedure-related mortality rate in geriatric patients was at least 2% in this study. CONCLUSION: Although the prevalence of complications after PEG in this study of multimorbid geriatric patients is within the expected range, the procedure-related mortality is higher than expected.

Laparoscopic organ-sparing resection of von Hippel-Lindau disease-associated pancreatic neuroendocrine tumors.

BACKGROUND: Pancreatic neuroendocrine tumors (PNETs) are a characteristic feature of the tumor syndromes multiple endocrine neoplasia type 1 (MEN-1) and von Hippel-Lindau disease (VHL). With VHL, about 10% of the patients exhibit PNETs by age 40 years. Metastatic potential is high if the tumors have grown to >3 cm in diameter. Optimal surgical treatment is still a challenge. METHODS: We report three cases, all women, ages 22, 30, and 39 years, respectively, who had known VHL, confirmed by classic organ manifestations and germline mutations of the VHL gene. All were diagnosed, in an asymptomatic stage, with solid tumors of the pancreatic tail or tail/corpus area measuring 2.9-5.6 cm diameter. All accepted the offer of laparoscopic organ-sparing removal of the tumors. RESULTS: In all three cases, the tumor was entirely removed. In two cases, resection of the spleen was also necessary as dissection of the tumor from the major splenic vessels was impossible. Operating time was 215-365 min, and blood loss was 200-700 ml. Histolopathology revealed benign PNETs in two cases, but the third patient had regional lymph node metastases. There were no complications, and the hospital stay was 4-7 days. CONCLUSIONS: Organ-sparing laparoscopic surgery is an important option for treating VHL-associated PNETs of the pancreatic tail.