Ricardo Lozano

Initial results of a new procedure for treatment of malignant obstruction of the left colon

PURPOSE: This study was undertaken to analyze the results obtained in 38 unselected patients using a new and original procedure for treatment of malignant obstructions of the left colon. METHOD: This procedure involves three phases: 1) resolution of the obstruction by means of a stem placed at the site of the tumor; 2) recovery of the general state of the patient, study of the extent of disease, and mechanical preparation of the colon; 3) regulated and final surgery (if this is not suitable, the stent may be used as definitive palliative treatment). RESULTS: In 35 patients (92 percent), the obstruction was resolved with the stent. In 22 patients the three phases were completed, and in 13 patients the stent constituted definitive palliative treatment. Only one patient (2.6 percent) died after resection of the tumor. CONCLUSION: This procedure offers a new, safe, and efficacious option for treatment of neoplastic colorectal obstructions.

Large hepatic ablation with bipolar saline-enhanced radiofrequency: an experimental study in in vivo porcine liver with a novel approach

SUMMARY BACKGROUND DATA Radiofrequency ablation (RFA) is a relatively new technology for the local destruction of liver tumors. Development of recent devices has enabled the creation of larger lesions. Nevertheless, treating liver tumors larger than 2.5 cm in diameter often requires multiple overlapping ablations to encompass the tumor and the surrounding healthy tissue rim with an increasing risk of local recurrence. MATERIAL AND METHODS RFA (480 kHz) of the liver using our method was undertaken on a total number of 15 healthy farm pigs with (Group B, n = 8) or without (Group A, n = 5) the Pringle maneuver via laparotomy. The pigs were followed and euthanized on the seventh day of the experiment. Livers were removed for histological assessment. Time of the procedure, impedance, current, power output, energy output, temperatures in the liver, central temperature of the animal, volume size of the lesion, and delivered energy per lesion volume were determined and compared among groups. Additionally a regularity ratio (RR) was determined by gross examination of the specimen and scored (0-3) taking into account regularity and predictability of the ablation with pathologic assessment. RESULTS With both methods, ellipsoid lesions were created between the two probes. In both groups tissue impedance fell with time (r = -0.47, P < 0.01 and r = -0.34, P < 0.05, in Groups A and B, respectively). The mean lesion size achieved with the Pringle maneuver was the largest lesion size described in the literature for any RFA method in vivo and was greater in Group B than in Group A (123.22 cm(3) +/- 49.62 and 52.40 cm(3) +/- 23.59, respectively, P < 0.05). A better regularity and predictability evaluated by RR was observed in Group B compared to Group A (1.88 +/- 1.35 and 0.40 +/- 0.55, respectively, P < 0.05). Five major complications were described and attributed primarily to failure in isolation from hypertermic lesions. CONCLUSIONS Our new bipolar saline-enhanced electrode with Pringle maneuver achieves large hepatic ablations in in vivo pig liver. These large lesions are well-tolerated by the animal when thermal injuries to adjacent structures are avoided.

Musculoskeletal hydatid disease: A report of 13 cases

This is a retrospective study of 13 patients with muscular hydatidosis - i.e., 4% of the 309 cases of hydatid disease treated in our department during 1983-1999. The commonest clinical finding was an asymptomatic and slowly growing mass (7). Puncture or incision of the mass was followed by an infection of the cystic cavity with fistulization in 2 patients. The immunological findings were false negative in 4 patients. MR images were obtained in 4 patients before diagnosis, and were highly suggetive of hydatid disease. The cystic cavities in all 9 patients subjected to radical surgery healed without chemotherapy. Radical surgery was not possible in 4 cases, in 3 of whom the sacrum was involved. Medical treatment of these patients did not eliminate the disease and new operations were necessary.

Improved perfusion system for bipolar radiofrequency ablation of liver: preliminary findings from a computer modeling study

Current systems for radiofrequency ablation of liver tumors are unable to consistently treat tumors larger than 3 cm in diameter with a single electrode in a single application. One of the strategies for enlarging coagulation zone dimensions is to infuse saline solutions into the tissue through the active electrodes. Nevertheless, the uncontrolled and undirected diffusion of boiling saline into the tissue has been associated with irregular coagulation zones and severe complications, mainly due to reflux of saline along the electrode path. In order to improve the perfusion bipolar ablation method, we hypothesized that the creation of small monopolar coagulation zones adjacent to the bipolar electrodes and previous to the saline infusion would create preferential paths for the saline to concentrate on the targeted coagulation zone. Firstly, we conducted ex vivo experiments in order to characterize the monopolar coagulation zones. We observed that they are practically impermeable to the infused saline. On the basis of this finding, we built theoretical models and conducted computer simulations to assess the feasibility of our hypothesis. Temperature distributions during bipolar ablations with and without previous monopolar coagulation zones were obtained. The results showed that in the case of monopolar coagulation zones the temperature of the tissue took longer to reach 100 degrees C. Since this temperature value is related to rise of impedance, and the time necessary for this process is directly related to the volume of the coagulation zone, our results suggest that monopolar sealing would allow larger coagulation zones to be created. Future experimental studies should confirm this benefit.

Determination of the Immunoglobulin E Postoperative Variation as a Measure of Surgical Injury

Abstract. The aim of this study was to ascertain postoperative changes in immunoglobulin E (IgE) in patients undergoing different types of surgery and the possible correlation with the duration and type of surgery. Evidence suggests that surgery induces a predominant activation pattern through the T-helper-2 (Th2) cell pathway, increasing interleukins (IL-4, IL-5, IL-10, IL-13), inhibiting Th1 cell activation, and promoting B and Th2 cell activation. IgE production may indicate predominant Th2 pathway activation and may be a more persistent and easily measurable postoperative marker than IL-6 for measuring surgical trauma. Altogether, 180 patients undergoing different types of surgery for nonneoplastic and nonparasitic diseases were studied. All patients received the same type of anesthesia. Before surgery and on the first (1PO) and 7th (7PO) postoperative days we determined in peripheral blood the CD3, CD4, CD8, CD16, and CD19 cell percentages; IL-1, IL-2, IL-4, IL-6, and tumor necrosis factor (TNF) levels; and the IgA, IgG, IgM, total IgE, C3, C4, and CIC levels. On 1PO, all variables decreased except IgE, IL-1, IL-2, IL-4, IL-6, CIC, and CD19. Only IgE, IL-6, and CD19 increases showed a significantly statistical (ss) difference regarding preoperative values (0.01, 0.05, 0.001, respectively). Relations between the IL-4 and IgE increases (p < 0.01) and between the IgG decrease and IgE increase (p < 0.001) were found. On 7PO, only IgE was increased (p < 0.001). The IgE increase correlated with surgical trauma intensity (p < 0.05). We concluded that IgE increases during the early postoperative period, correlating with surgical injury intensity. The increase in the IgE level may be detected 24 hours after surgery and during the first 7 postoperative days depending on the type of surgery.

RF tumor ablation with internally cooled electrodes and saline infusion: what is the optimal location of the saline infusion?

BackgroundRadiofrequency ablation (RFA) of tumors by means of internally cooled electrodes (ICE) combined with interstitial infusion of saline may improve clinical results. To date, infusion has been conducted through outlets placed on the surface of the cooled electrode. However, the effect of infusion at a distance from the electrode surface is unknown. Our aim was to assess the effect of perfusion distance (PD) on the coagulation geometry and deposited power during RFA using ICE.MethodsExperiments were performed on excised bovine livers. Perfusion distance (PD) was defined as the shortest distance between the infusion outlet and the surface of the ICE. We considered three values of PD: 0, 2 and 4 mm. Two sets of experiments were considered: 1) 15 ablations of 10 minutes (n ≥ 4 for each PD), in order to evaluate the effect of PD on volume and diameters of coagulation; and 2) 20 additional ablations of 20 minutes. The effect of PD on deposited power and relative frequency of uncontrolled impedance rises (roll-off) was evaluated using the results from the two sets of experiments (n ≥ 7 for each PD). Comparisons between PD were performed by analysis of variance or Kruskal-Wallis test. Additionally, non-linear regression models were performed to elucidate the best PD in terms of coagulation volume and diameter, and the occurrence of uncontrolled impedance rises.ResultsThe best-fit least square functions were always obtained with quadratic curves where volume and diameters of coagulation were maximum for a PD of 2 mm. A thirty per cent increase in volume coagulation was observed for this PD value compared to other values (P < 0.05). Likewise, the short coagulation diameter was nearly twenty five per cent larger for a 2 mm PD than for 0 mm. Regarding deposited power, the best-fit least square function was obtained by a quadratic curve with a 2 mm PD peak. This matched well with the higher relative frequency of uncontrolled impedance rises for PD of 0 and 4 mm.ConclusionSaline perfusion at around 2 mm from the electrode surface while using an ICE in RFA improves deposition of energy and enlarges coagulation volume.

Pharmacological Immunomodulation of Surgical Trauma

Surgery and accidental trauma induce changes in the immune response, showing a predominant pattern of activation through the Th2 cell pathway to the detriment of Th1 cell pathway activation. Anapsos is a hydrosoluble extract obtained from Polypodium leucotomos. Anapsos has shown immunomodulating effects in vitro. On a rat experimental model (tibia and fibula fracture), cytokines (interleukin [IL]-2, IL-4, IL-6, IL-10, and IL-12) (enzyme-linked immunosorbent assay, ELISA) and cell percentages of CD4, CD8 CD25, CD122, and CD132 (monoclonal antibodies, MoAb) were determined in peripheral blood 7 days before surgery (PRE), 1 day after surgery (1PO), and 7 days after surgery (7PO). On postoperative day 1, rats undergoing fracture show an increase of CD8 percent expression and IL-6 and IL-10 levels, in contrast to rats undergoing fracture plus anapsos treatment. On postoperative day 7, rats undergoing fracture show an increase of IL-6 levels, whereas rats undergoing fracture plus anapsos do not. The IL-12 level decreases on postoperative day 7 in the group with fracture but not in the fracture plus anapsos group. Thus, we conclude that anapsos is able to modulate the immune response after trauma, inhibiting Th2 pathway activation with no effect on Th1 pathway activation. In trauma, Anapsos could prevent the shifting Th1/Th2 balance.

Cirugía mamaria mínimamente invasiva: reconstrucción mamaria mediante colgajo muscular puro del gran dorsal

Resumen Introduccion Las tecnicas minimamente invasivas se han extendido a todos los campos de la cirugia, la cirugia mamaria es quiza la cirugia que mas se deberia beneficiar de estos conceptos, por sus caracteristicas especiales, reduce la agresion quirurgica y elimina u oculta cicatrices. El proposito de nuestro trabajo es presentar una nueva tecnica quirurgica para la reseccion de grandes volumenes de tejido mamario, incluida la mastectomia subcutanea completa, y reconstruccion mediante un colgajo del musculo gran dorsal con o sin material protesico, a traves de una minima incision cutanea. Pacientes y metodo Analisis retrospectivo de nuestra serie de 5 casos clinicos intervenidos con esta tecnica, que nos ha permitido ponerla a punto y establecer las indicaciones. Analizamos los detalles tecnicos, las complicaciones y los resultados. Resultados Hemos intervenido a 5 pacientes mediante esta tecnica quirurgica (1 con hamartoma gigante, 1 con carcinoma in situ multicentrico con enfermedad de Paget, 1 con tumor mamario maligno multicentrico y 2 con tumoraciones malignas unicas de cuadrantes externos) practicando resecciones oncologicas suficientes (2 resecciones parciales mamarias y 3 mastectomias subcutaneas) e incluian biopsia de ganglio centinela o linfadenectomia axilar completa. Tras un periodo de seguimiento medio de 10 meses no ha habido recidivas locales y el resultado estetico es excelente. Conclusiones La tecnica minimamente invasiva, a traves de una incision vertical en linea axilar posterior, permite realizar una reseccion mamaria parcial o completa, asi como una reconstruccion inmediata mediante tejido autologo o material protesico.

Premature roll-off in radiofrequency ablation using bipolar saline-enhanced electrodes

Sir, We have read with interest the article by Lee et al. [1]. The authors tried to compare two radiofrequency bipolar systems: the Berchtold system with open-perfused electrodes (bipolar saline-enhanced electrodes) and the Radionics system with cooled-wet electrodes in bipolar mode. We would like to congratulate the authors for their experimental design and excellent results. However, the work raises some concerns. First of all, the accumulated energy output was 87,555.1±86,787 Ws (joules) for the open-perfused electrode group when the maximum power output for the generator was 60 W for 20 min (that means a maximum energy output of 72,000 Ws per experience). Furthermore, the huge variability expressed by the standard deviation in output energy deposition means that in some cases, less than 1,000 Ws were deposited, while in other cases more than two times the maximum output energy was employed. Actually, on the basis of the authors’ explanation, the main reason for the reduced ablation dimension in the open-perfused group compared with the cooled-wet group is the premature rise of the impedance over 700 Ω. This premature roll-off of the impedance is related to the more intense desiccation and charring of the tissues in a bipolar mode compared with the monopolar configuration caused by a higher current deposition in the small amount of tissue interposed between the electrodes, when no diversion of the heat occurs. We agree with this latest statement, and in our experiences we adapted the power to the global distance to the electrodes in order to keep the impedance low, as is also discussed in [2]. For example, for a 7-cm distance of the electrodes, we employ advantageously less than 40 W with more perfusion of saline for an in vivo application in a similar configuration [3], whereas Lee et al. employ 60 W for only a 3-cm separation between the electrodes with less perfusion of saline. The power algorithm the authors uses is usually employed for a monopolar configuration when more diversion of heat occurs, but in a bipolar setting one may overheat the tissue prematurely. This can account for the premature roll-off in the authors’ open-perfused group and for their suboptimal employ of an open-perfused electrode. Secondly, in the authors’ bipolar configuration the electrodes must be placed parallel, as we previously considered and abandoned [4, 5], because, as the authors state, the insertion of both electrodes encompassing the tumor could be difficult. In the actual configuration we have integrated both electrodes in one needle, making electrode placement more accurate and safe [3]. Lee et al. state that one of the axes of the coagulation area we created An author’s reply to this letter is available at http://dx.doi.org/10.1007/s00330-005-2650-z.

Small ablation zones created previous to saline infusion result in enlargement of the coagulated area during perfusion RF ablation: an ex vivo experimental study.

One of the strategies for enlarging coagulation zone dimensions during RF ablation of liver tumours is to infuse saline solutions into the tissue during ablation. The aim of this study was to evaluate experimentally whether the creation of a small coagulation adjacent to a bipolar RF applicator and prior to perfused RF ablation would allow enlargement of the coagulation zone. Thirty bipolar RF ablations (group A, n = 15; group B, n = 15) were performed in excised bovine livers. Additionally, in group B a monopolar RF application (60 W, 20 s) was performed before bipolar ablation using three small additional electrodes. Electrical parameters and dimensions of the ablation zone were compared between groups. Despite the fact that all three ablation zone diameters were greater in group B, only one of the minor diameters was significantly longer (5.52 +/- 0.66 cm versus 4.87 +/- 0.47 cm). Likewise, volume was significantly bigger in group B (100.26 +/- 24.10 cm(3) versus 79.56 +/- 15.59 cm(3)). There were no differences in the impedance evolution, allowing a relatively high constant power in both groups (around 90 W). The efficacy of delivering energy (expressed as the delivered energy per coagulation volume) was significantly better in group B, showing a lower value (578 J cm(-3) versus 752 J cm(-3)). These results suggest that the creation of small ablation zones prior to saline infusion improves the performance of this perfusion system, and hence the total volume.