Radiologic and Clinical Outcomes of Surgery in High Grade Spondylolisthesis Treated with Temporary Distraction Rod

BACKGROUND: Surgical techniques used in the treatment of patients with high grade lumbar spondylolisthesis (> 50% slippage) are usually associated with a great deal of controversies. We aim to evaluate the surgical outcomes of high grade spondylolisthesis treated with an intraoperative temporary distraction rod. METHODS: We retrospectively studied 21 patients (14 females and 7 males), aged 50.4 +/- 9.2 years, who had high grade lumbar spondylolisthesis that was treated with intraoperative temporary distraction rods, neural decompression, pedicular screw fixation, and posterolateral fusion involving one more intact upper vertebra. The mean follow-up period was 39.2 months. Radiologic and clinical outcomes were measured by slip angle, slip percentage, correction rate, Oswestry Disability Index (ODI), visual analogue scale (VAS), patient's satisfaction rate in the pre- and postoperative period. Data were analyzed by SPSS ver. 11.5. RESULTS: Analysis of the preoperative visits and final follow-up visits indicated that surgery could improve ODI, lumbar VAS, and leg VAS from 60.5% to 8.2%, from 6.7 to 2.2, and from 6.9 to 1.3, respectively. Slip angle and slip percentage were also changed from -8degrees to -15degrees and from 59.2% to 21.4%, respectively. Mean correction rate at the final follow-up visit was 64.1%. Loss of correction was insignificant and a neurologic complication occurred in one patient due to misplacement of one screw. Excellent and good levels of satisfaction were observed in 90.5% of the patients. CONCLUSIONS: In the surgical treatment of refractory high grade spondylolisthesis, the use of a temporary distraction rod to reduce the slipped vertebra in combination with neural decompression, posterolateral fusion, and longer instrumentation is associated with satisfactory clinical and radiologic outcomes.

Is [99m]Tc-MIBI scintigraphy a predictor of response to pre-operative neoadjuvant chemotherapy in osteosarcoma?

Multidrug resistance [MDR], which may be due to the over expression of P-glycoprotein [Pgp] and/or MRP, is a major problem in neoadjuvant chemotherapy of osteosarcoma. The aim of this study was to investigate the role of Tc-99m MIBI scan for predicting the response to pre-operative chemotherapy. Twenty-five patients [12 males and 13 females, aged between 8 and 52y] with osteosarcoma were studied. Before the chemotherapy, planar [99m]Tc-MIBI anterior and posterior images were obtained 10-min [tumor-to-background ratio: [T[1]/B[1]][10min]] and 3-hr after tracer injection. After completion of chemotherapy, again [99m]Tc-MIBI scan was performed at 10-min after tracer injection. In addition to calculation of decay corrected tumor to background [T/B] ratios, using the 10-min and 3-hr images of the pre-chemotherapy scintigraphy, percent wash-out rate [WR%] of [99m]Tc-MIBI was calculated. Using the 10-min images of the pre- and post-chemotherapy scans, the percent reduction in uptake at the tumor site after treatment [Red%] was also calculated. Then after surgical resection, tumor response was assessed by percentage of necrosis. All patients showed significant [99m]Tc-MIBI uptake in early images. Only 9 patients showed good response to chemotherapy [necrosis >/= 90%] while 16 patients were considered as non-responder [necrosis <90%]. There was no statistical significant difference between non-responders and responders in [T[1]/B[1]] [10min].There was a significant negative correlation between WR% and percentage of necrosis [P=0.001]. On the other hand, there was a significant correlation between Red% and percentage of necrosis [P<0.001].There was also statistical significant difference in WR% and Red% between non-responders and responders [both P< 0.001]. Washout rate of [99m]Tc-MIBI in pre-chemotherapy scintigraphy as well as Red% using pre- and post-chemotherapy MIBI scintigraphy are useful methods for predicting response to neoadjuvant chemotherapy