Patients with thoracic and thoracolumbar spinal tuberculosis often shows spinal instability, spinal cord decompression and spinal deformity due to bone destruction and paravertebral or intraspinal abscess. Most patients with spinal tuberculosis can be cured by conservative treatment. Many patients with spinal cord dysfunction can be treated conservatively as effectively as with the urgent early surgical treatment, even patients with tuberculosis of the craniovertebral junction can achieve complete clinical and radiological healing.[25, 26] The surgical management options for spinal tuberculosis remain controversial. However, the surgical treatment to clear tuberculous foci, sclerotic bone, multiple cavities, and bony bridges had been reported to increase curative effect in spinal tuberculosis. Patients treated conservatively have potential to end up with serve deformity and spinal cord compression. The purpose of the surgery of thoracic and thoracolumbar spinal tuberculosis is to relieve spinal cord or nerve compression, to reconstruct the spine stability and remove the vertebral lesion and obvious abscess thoroughly.[29-31] The aim of this study is to evaluate the efficacy and feasibility of allograft bone using titanium mesh and the bony fusion in the posterior-only surgical treatment of thoracic and thoracolumbar spinal tuberculosis.
Various surgical managements have been performed on the patients with spinal tuberculosis patients, including anterior surgery, posterior surgery, and combined anterior-posterior surgery. It had been well recognized that the posterior surgery plays a crucial role in the spinal tuberculosis management. Zhou et al.  reported that compared to combined anterior-posterior surgery for the treatment of thoracic and thoracolumbar spinal tuberculosis, posterior surgery could achieve a similar curative effect, and was associated with the advantage of shorter operation time, less blood loss, and shorter hospital stay. The posterior surgical approach is considered better for the reconstruction of spinal stability and the correction of kyphosis. The advantages of posterior surgery include minimum surgical trauma, satisfactory pain relief, excellent neurological recovery, and reconstruction of the spinal stability. Posterior-only surgical approach in spinal tuberculosis is effective in correcting the kyphosis and has achieved satisfactory clinical efficacy. Many researches articles have mentioned the advantages of posterior surgical approach focused on the clinical characteristics, including operation time, blood loss, length of hospital stay, reconstruction of spine stability, neurological recovery, and kyphosis correction. The reconstruction of spine stability and the correction of kyphosis in the posterior surgical approach depends on the posterior fixation devices and the anterior implantation materials, including autogenous or allogeneic bone with or without cages or titanium mesh. When it comes to bony fusion, the distinction of different implantation materials has not been elaborated in detail.
In our study, like previous studies, all patients achieved pain relief after the surgery and at the final follow-up. The average VAS score and the average ODI score decreased after surgery and at the final follow-up. Compared with preoperative scores, the VAS and ODI scores were significantly improved before discharge and at the final follow-up (P < 0.001). Moreover, neurological status improved after posterior-only surgical management. Postoperative and follow-up ASIA classification showed visible improvement, which suggests good efficacy and feasibility of posterior-only management for thoracic and thoracolumbar tuberculosis in the improvement of clinical symptoms.
Even though the surgical management of spine tuberculosis are previously studied, the outcome of intervertebral fusion and the reconstruction of large bony defects remain controversial in the posterior-only surgical approach. The methods to reconstruct anterior bony defects include autologous bone (rib or iliac bone), allograft bone grafts, and titanium mesh with autologous or allograft bone particles. One-stage surgical treatment via a posterior-only approach with appropriately sized autologous bone or allograft bone block only is effective and feasible for the treatment of spinal tuberculosis. Therefore, compared with autogenous iliac bone grafts, titanium mesh cages could serve as a superior material in posterior-only surgical approach for thoracic and lumbar spinal tuberculosis. Satisfactory bony fusion and reconstruction of spinal stabilization using titanium mesh with autogenous or allogeneic bone have been well defined. Various findings suggested the advantages of using titanium mesh in patients with osteoporosis and poor iliac bone quality: minor surgical invasion, less complications, effective reconstruction of large defects, and ideal sagittal alignment in lumbosacral tuberculosis. It has been reported that one-stage posterior interbody autogenous graft using titanium mesh cages achieved satisfactory bone fusion in the aged patients with lumbosacral spinal tuberculosis. Ukunda et al.  demonstrated that the posterior-only approach using cortical allografts for anterior column reconstruction produced good clinical and radiological outcomes. Titanium mesh with autologous or allograft bone particles in the posterior surgery could construct the bony defects effectively. However, the detailed fusion of allograft bone using titanium mesh in the posterior-only surgery for thoracic and thoracolumbar spinal tuberculosis has not been investigated separately.
In our study, we retrospectively analyzed the patients with thoracic and thoracolumbar spinal tuberculosis who were treated with one-stage posterior debridement, allograft bone graft using titanium mesh, posterior instrumentation, and fusion. We have preferred the allograft using titanium mesh in order to avoid additional autograft harvesting with potential complications. According to previous studies, titanium mesh provide better anterior column support and lower kyphosis angle loss rate.[11, 20, 21, 32, 35-37] Similarly, this study has also concluded that the correction of kyphosis was achieved with satisfactory postoperative cobb angle and acceptable loss of correction. The correction rate and kyphosis angle loss rate as other evaluation indicators for the posterior fixation effectiveness and the anterior bony fusion rate were also summarized. Luo et al. reported a 62.4% correction rate and a 5.5% loss rate of the kyphosis angle in 25 thoracic and thoracolumbar spinal tuberculosis patients who were treated with the posterior approach. Comparing with this study, similar results were concluded in our study. All patients in our study used titanium mesh with allograft to reconstruct the anterior bony defects. All patients achieved bone fusion, including twenty-eight patients with complete fusion (Grade I) and four patients with partial fusion (Grade II), as evaluated by the X-ray and CT images. Loss of correction was not significant in the patients with partial fusion. No graft fracture, infection, or resorption was observed.
The small sample size, the lack of a control group, and study in a single center are the limitations of the study. In conclusion, however, allograft bone using titanium mesh in the posterior-only surgical treatment of thoracic and thoracolumbar spinal tuberculosis achieved good bony fusion according to the radiological evaluation. The satisfactory fusion indicates that allograft bone using titanium mesh can be applied successfully in the spinal tuberculosis patients, especially in patients with osteoporosis and poor iliac bone quality.