| Objective: The first purpose of this study was to investigate the heat isolation effect of posterior cortical bone and estimate the safety parameter avoiding damage of the spinal cord for radiofrequency ablation(RFA) in the in vivo study.The second purpose was to evaluate the safety and efficacy of vertebrectomy combined with RFA for treatment of spinal metastases in a retrospective analysis.Methods: 1. Clinical data of 49 patients who were diagnosed with spinal metastasis between April 2009 to December 2012 were analyzed. The recruited participants were divided into two groups: one intervention group of 23 patients receiving vertebrectomy combined with RFA and another control group of 26 patients receiving vertebrectomy only. Assessed the visual analog scale(VAS), sensory and motor function(Frankel scale), recurrence rate and time of recurrence, blood loss and operation time of two groups of patients before the treatment and reassessed them at 1 month and 6 months after procedures. Comparing two groups of patients with these features.2. Four swines were given spinal surgeries under general anesthesia in prone position and RFA was performed at 95?/75 W or 100?/75 W in the L1,L3,L5 of each swine while real-time monitoring the intrathecal temperature of the operational vertebr with Optris Infrared Thermometer. The effective length of the radiofrequency ablation electrode was setted on 2.0cm and RFA was performed for 15 minutes. Perform 6 times repeated trials with a same parameter and there were 12 lumbar vertebra in this experiment.3. Six swines were given spinal surgeries under general anesthesia and RFA was performed at 100?/75 W in the lumber vertebra of each swine while real-time monitoring the intrathecal temperature of the operational vertebr with Optris Infrared Thermometer. The effective length of the radiofrequency ablation electrode was setted on 2.0cm and RFA were performed for 5 minutes,8 minutes,10 minutes and 12 minutes,respectively.Results: 1. The results showed for the both groups the visual analog scale(VAS) pain score was decreased and the neurological status was improved after treatment. The combination group had less intraoperative blood loss(P=0.002) and shorter operation time(P<0.001). The recurrence rate was lower(P=0.003) in the patients received combined treatment and the interval time of local recurrence was prolonged(P=0.030) by combined treatment.2. The mean highest temperature within the spinal canal of the group of 95 ?or 100 ?was 41.07±1.96 ?(39.0? ~ 44.2?) and 48.98±5.00 ?(45.6? ~50.1?),respectively. The mean ablation zone was 2.25±0.18 cm and 2.53±0.15 cm,respectively(P=0.016).3. The mean highest temperature within the spinal canal of the group of 5min, 8min, 10 min or 12 min was 41.8±1.1?,44.4±1.3?,45.9±2.1?,48.5±0.5?,respectively. The mean ablation zone was 1.45±0.30 cm,1.91±0.21 cm,2.08±0.17 cm and 2.46±0.19 cm,respectively.Conclusions: 1. Vertebrectomy combined with RFA might improve surgical outcomes and decrease recurrence rate. Therefore the combined application of vertebrectomy and RFA is probably a practical treatment option for patients of spinal metastases.2. The highest temperature within the spinal canal of the group of 95 ?was lower than 45 ?when the effective length of electrode was 2cm and the setting power was 75 W.3. The highest temperature within the spinal canal of the group of 100 was higher ?than 45 ?when the effective length of electrode was 2cm and the setting power was 75 W.4. The highest temperature within the spinal canal of the group 1 and group 2 was lower than 45 while the other groups were higher than 45? ?.5. The ablation ranges keep growing when the time prolonged(5min, 8min, 10 min, 12min). The difference between group 2(8min) and group 3(10min) didn't significant statistically while the others has statistical difference. |
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