Sympathetic chain clipping for hyperhidrosis is not a reversible procedure.

BACKGROUND: Many techniques have been used to treat palmar hyperhidrosis. Compensatory sweating is a difficult adverse effect. Clipping has been proposed because of its supposed reversibility when clips are removed at a later date. The primary aims of this article are to investigate the neuronal lesion of the sympathetic chain caused by clipping and to study the possibility of regeneration after removal of the clips. METHODS: We performed an experimental study at the Minimally Invasive Surgery Centre Jesus Uson in Caceres (Spain). We used a swine model, performing clipping, unclipping, and extirpation of different segments of sympathetic chain with clips and after clip removal, following a chronogram of 10, 20, and 30 days. Pathologic studies of specimens and statistics were done at the University of Seville. RESULTS: Ten days after clipping, all sympathetic chains displayed evident Wallerian degeneration. Twenty days after clipping, Wallerian degeneration of myelinated fibers was more widespread and also more striking. Thirty days after clipping, a very marked macrophagic reaction was visible, with multiple signs of phagocytosis of myelin debris. By 30 days post operation and 20 days after clip removal, a few residual myelin and amyelinated fibers were visible. These findings suggest that axon regeneration is not possible. CONCLUSIONS: There are Wallerian degeneration and axon loss 10 days after clipping. The almost total absence of myelinated and amyelinated fibers following clip removal suggests that there was no nerve regeneration, and that therefore clipping cannot be considered a reversible technique.

Preliminary results with a training program for thoracoscopic atrial fibrillation therapy.

BACKGROUND: Novel devices have been designed for the treatment of atrial fibrillation (AF) using minimally invasive approaches. This study aimed to determine the usefulness of a sheep model for training in cardiac surgical ablation using a minimally invasive approach in an experimental hands-on training course. METHODS: After initial training using a laparoscopic pelvic trainer, 15 sheep were subjected to surgery by six thoracic surgeons attending a hands-on thoracoscopic course. Dissection to the posterior wall of the pulmonary veins was followed by insertion of a microwave device around both the caudal cava vein and the pulmonary veins. The complications were recorded, and the effectiveness of the surgery was evaluated by complete deployment of the microwave device. The animals were killed after completion of the procedure. RESULTS: Isolation of the cava vein and the pulmonary veins and placement of the microwave probe were performed successfully for 10 animals using a complete thoracoscopic approach. Two animals died during the procedure. The main complications of the procedure were hemorrhage and difficulty isolating the blood vessels using a minimally invasive procedure. After the training period, the thoracoscopic surgical maneuvers were accurate and reliable. CONCLUSION: The technical feasibility of performing safe and efficient thoracoscopic placement of a microwave device in a sheep model was demonstrated in this study, suggesting that the results of this study are a useful contribution to the development of an animal model for surgical training and experimental cardiac surgeries.

A new model of abdominal aortic aneurysm with gastric serosa patch: surgical technique and short-term evaluation.

The purpose of this work was to develop an abdominal aortic aneurysm (AAA) model that resembles human aneurysms with potential for further growth, patent collateral vessels, and a predictable tendency to rupture, and that can be used in the development of new endoprostheses and implant training. An infrarenal AAA model was created in five domestic swine using an autologous gastric serosal patch. Pre- and postsurgical digital subtraction aortograms (DSA) were obtained to document the appearance and dimensions of the aneurysm. Animals were followed up with DSA and ultrasonography on days 7, 14, 30, 45, 60, and 90 after model creation. Aneurysmal diameters were measured with both techniques in all examinations. On day 90, animals were euthanized, target arteries were harvested, and pathological evaluation was performed. The nonparametric Wilcoxon test was used to assess any differences in measured diameters. All the animals survived the surgical procedure. The aneurysmal diameters increased from 8.14+/- 2.15 to 13.28+/- 1.18 mm immediately after surgery (p < .05), but no subsequent significant growth of the aneurysmal sac was seen during follow-up. In this experimental setting, measurements obtained with DSA were slightly larger than those obtained with ultrasound. Two animals died of AAA rupture on days 6 and 10 (40% rupture rate). Pathological examination showed lack of elastic laminae and increased collagen content in the aortic patch. Thus, model showed a tendency to rupture, but no significant potential for further aneurysmal growth. It might be useful for training in endovascular therapies, but its usefulness for preclinical endovascular device testing is limited by its lack of growth potential.

Comparison of a new recirculation thrombectomy catheter with other devices of the same type: in vitro and in vivo evaluations.

RATIONALE AND OBJECTIVES: To compare a new 7 Fr. Helix thrombectomy catheter with Amplatz thrombectomy devices (ATD) with respect to clot fragmentation efficiency, hemolytic potential, and risk for vascular trauma. MATERIALS AND METHODS: Particle size was evaluated following the maceration of 8-to-10-day-old clots, each weighing 6 +/- 0.01 g. The clots were macerated using devices of various sizes, including the 7-Fr. Helix thrombectomy catheter, the 7-Fr. over-the-wire (OTW), 8-Fr. ATD and the 6-Fr. ATD. The number of particles by weight was quantified. The 7-Fr. Helix and the 8-Fr. ATD were tested in the native iliac vein of six dogs without presence of clots. Blood samples were obtained before, during, and at 1, 3, 6, 24, and 48 hours after the procedure, to monitor the hemolytic effects. The treated iliac veins were examined histologically. RESULTS: Most of the clot was fragmented into particles <10 microm. The mean percentage by weight of the original clot that remained as particles larger than 10 microm was 1.59% in the 7-Fr. Helix group. This was significantly less than 3.10% with the 6-Fr. ATD, 2.57% with 7-Fr. OTW and 2.44% in the 8-Fr. ATD group (<0.01). In vivo results showed a higher plasma free hemoglobin (PFH) level starting 5 minutes after initiating the ATD activation, reaching its peak after completion of the activation, and declining afterward, with return to the baseline at 24 hours. The haptoglobin level tended to decline slightly at 10 minutes, reaching its lowest level at 24 hours, and starting to recover at 48 hours. A similar pattern of PFH and haptoglobin changes was found in both groups. There were no significant differences regarding hemolytic effect of the two tested devices. No significant changes of creatinine were observed for up to 48 hours after procedures. Focal microthrombosis was seen in two sites of two vessels treated with the 7-Fr. Helix and a focal injury of a venous valve was noted in the 8-Fr. ATD group. The media and internal elastic lamina (IEL) were intact in all cases. CONCLUSION: The newly designed 7-Fr. Helix is more effective in fragmentation in vitro clots than the 6 Fr. ATD, 7-Fr. OTW and the 8-Fr. ATD. The 7-Fr. Helix and the 8-Fr. ATD produced hemolytic effects, but they appeared to be tolerated by the animals. The in vivo results indicated that the 7-Fr. Helix appears to be as safe as the 8-Fr. ATD.