To explore the clinical value of nano-hydroxyapatite/polyamide 66 (nano-hydroxyapatite/polyamide 66, n-ha/PA66) tubular bone in the reconstruction of posterior-only thoracolumbar metastatic tumor resection.

A retrospective analysis of 12 cases of patients with thoracolumbar metastatic tumors from January 2015 to July 2017. All patients underwent posterior-only tumor resection and reconstruction with n-ha/PA66 tubular bone. There were 7 males and 5 females with an average (53.5±12.8) years (range, 39~72 years) Among them, 1 neuroendocrine carcinoma, 4 breast cancer, 1 lung cancer, 1 rectal cancer, 2 myeloma, 1 liver cancer, 1 kidney cancer and 1 prostate cancer. There were nine patients with single thoracic vertebral metastasis, 1 patient with two thoracic vertebra metastasis and 2 patients with lumbar vertebrae metastasis. The preoperative visual analogue score (VAS) was (7.4±0.5); The Frankel grade of neurologic function was E in 2, D in 4, C in 6.

In all cases, the tumor resection and spine reconstruction were performed in a posterior-only approach. The average operation time was (245.0+ 46.2) min, the blood loss was (1750+ 342.5)ml. Incisions healed by first intention in all patients. Postoperative complications occurred in 3 cases, including 1 pulmonary infection, 1 pulmonary atelectasis and pleural effusion, 1 pleural rupture. All complications were relieved after conservative treatment. One month later, the patient's pain symptoms were significantly relieved, and the VAS score was 3.5 or 0.5 (P<0.01). The postoperative neurological function was significantly improved. All patients received postoperative follow-up with an average time of (13.8±8.2) months (range, 5~36 months), 1 case died due to the progression of breast cancer, 1 case die of liver cancer and 1 case die of lung cancer. 1 case of rectal cancer had local recurrence at 11 months follow up. There were multiple metastases in both cases (case no. 8, 11). X-ray and CT scan suggested the intervertebral height of the adjacent segments was improved from (30.9±6.6)mm preoperatively to (33.7±7.3)mm postoperatively (p<0.01). The adjacent segments Cobb angle was (24.8±8.7)° preoperatively improved to (9.9±1.8)° postoperatively (P<0.01). Tubular bone sinking and rod fracture was observed in neuroendocrine carcinoma metastasis patient with Cobb angle 24.5° at 30 months follow up. The remaining case obtained good spinal stability without displacement and subsidence of the n-HA/PA66 tubular bone.

n-HA/PA66 tubular bone can effectively reconstruct vertebral body height, correct kyphosis deformity and maintain the stability of the spine and have a good application prospect in the reconstruction of thoracolumbar metastasis tumor posterior-only resection.

Spinal metastasis tumor; Vertebrectomy; Repair and reconstruction; Nano-hydroxyapatite/polyamide 66