Abstract: Objective To explore the clinical effect of the nano-hydroxyapatite／polyamide 66(n-HA／PA66) composite in treating thoracolumbar spinal tuberculosis.  Methods Sixty patients (36 males, 24 female; age, 19-75 years old, averaged (42.4±10.6) years old) with thoracic or lumbar tuberculosis admitted in Guangzhou Chest Hospital from January 2012 to June 2013, which were received anterior debridement and treated by padding artificial bone by nano-hydroxyapatite/polyamide 66. Among the 60 patients, the lesion located at thoracic vertebra in 29 patients, thoracolumbar in 16 patients, upper lumbar in 15 patients; and in which 2 vertebrae were damaged in 47 patients, 3 vertebrae were damaged in 11 patients, and vertebrae were skipped damaged in 2 patients. There were 49 cases of kyphosis in the 60 patients, the average Cobb angle was (29.3±3.6)°. The erythrocyte sedimentation rate(ESR) was 35-126 mm/1 h before the operation, averaged (59.8±13.9) mm/1 h. The evaluation indicator include the Cobb angle, ESR and the neural function by Frankel system before and after the operation, and the bone graft fusion and the rate of n-HA／PA66 composite subsidence by examining the thoracolumbar anterioposterior and lateral film and the three-dimensional CT image.  Results The period of follow-up was 8-30 months (the median time 17.5 months), all the incisions healed by the first intention, there was no failure of internal fixation. The immediate postoperative average Cobb angle was (13.1±4.5)°, the last follow-up was (14.8±4.0)°, the lost of Cobb angle was (1.7±0.5)°. By the last follow-up, the spinal cord Frankel grading elevated by grade 0-2 respectively in the 31 patients who diagnosed incompletely paralysis(Frankel grade B or C or D), in which 4 patients of Frankel B preoperative 1 patients elevated 1 grade and 3 elevated 2 grade, in which 8 patients of Frankel C preoperative 3 patients elevated 1 grade and 5 elevated 2 grade, and 19 patients of Frankel D preoperative 18 patients elevated 1 grade and 1 unchanged. By the final follow-up, the E was 34 patients, the D was 23 patients, the C was 2 patients and the B was 1 patients by the bone graft fusion which was evaluated with Brantign grading criteria, the bone graft fusion rate was 95.0%(57/60), the bone graft fusion time was 4-8 months(the median time 5.5 months). The average n-HA／PA66 composite subsidence was (1.6±0.7)mm, in which 2 patients’ subsidence ＞3 mm, the rate of subsid-ence was 3.3%(2/60), there were no internal fixation shift or fracture. The time of ESR normalization was 3-7 months (the median time 4.5 months).  Conclusion The n-HA／PA66 composite has very important clinical effect in treating thoracolumbar spinal tuberculosis.

Key words: Tuberculosis, spinal/surgery, Thoracic vertebrae, Lumbar vertebrae, Hydroxyapatites, Nylons, Nanoparticles, Spinal fusion, Tissue scaffolds