The results indicate that anterior surgery has the shortest hospitalization time, the shortest operation time and the least bleeding. Three open surgical approaches varied in operation time, intraoperative blood loss, and hospital stay, with a statistical difference (P < 0.05). In the anterior-posterior approach group, the average length of hospital stay, operative time and intraoperative blood loss were significantly longer, compared with the other two groups, the average hospital stays were 15 days in the anterior-posterior group, and the average of 13.5 days in other groups. The average time for anterior-posterior surgery was about 210 minutes, while 140 minutes in the anterior group and 153 minutes in the posterior group respectively. In terms of blood loss, anterior-posterior surgeries were the most, 482ml on average, anterior 295ml and posterior 385ml respectively. Yu et al reported a case series of 21 patients who were treated by posterior debridement and internal fixation with bone grafting, and suggested the advantages of the posterior approach in the amount of bleeding and the operative time, compared with the 27 patients treated by anterior surgery[16]. Hassan K compared the outcomes of thoracolumbar discitis by anterior and posterior approach, and they found that the anterior approach has advantages over the posterior one in operative time and the amount of bleeding[17].
Kush et al aimed at whether patients with spinal tuberculosis need surgery and proposed the natural history and level of tuberculosis, they divided the disease into five levels due to symptoms combined with neurological deficits and the patients with a rating greater than level three are supposed to receive surgery[18]. Zhang et al indicated that surgery could be a necessary way of the treatment of lumbar tuberculosis and suggested a posterior approach instead of an anterior approach[19, 20]. A cohort study including 74 patients with anterior surgery and 83 patients with posterior surgery reported by Ma et al also supported the posterior approach in curative effect[21, 22]. Nevertheless, Jin et al suggested that the anterior surgical approach could achieve early spinal reconstruction and stabilization, the assistance with posterior internal fixation was mainly applicable to younger patients[23]. Besides, Zeng et al compared three approaches and indicated that the loss of kyphosis correction was the highest in the anterior group and all three approaches could improve kyphosis and nerve function, while the amount of bleeding was higher in the anterior-posterior combined group[24–27]. In this study, all three surgical methods can significantly improve neurological function and kyphosis angle, as well as reduce ESR, CRP, VAS and ODI score, and achieve satisfactory clinical healing due to complete debridement, effective nerve decompression and the use of chemotherapy drug. The characteristics of spinal tuberculosis, including bone destruction, local pus, dead bone formation, and local TB granulomatous inflammation, may lead to the focus of infection of tuberculosis in vertebral body. After regular chemotherapy treatment, surgery is essential to focal cleaning and bone graft reconstruction regardless of the surgical approach[28]. The reduction of postoperative ESR, CRP, and pain score and the improvement of dysfunction index, the neurological function score, as well as nutrition support and anti-TB therapy could result in the cure of TB focus, the firm bone graft fusion, the local stability of the spine, and good long-term follow-up[28].
The longer average length of hospital stays and operative time, as well as more intraoperative blood loss appeared in the anterior-posterior group. Besides, a high incidence of complications occurs in the anterior-posterior group, compared with the anterior and posterior approach, which may result from the sinus of the wound caused by incomplete cleaning. At present, the incidence of anti-TB drug resistance is increasing, and the combination of drug use due to intraoperative specimens genetic and drug resistance tests is advocated to avoid the use of single or only two chemotherapy drugs. Furthermore, the duration of bed rest was relatively long in TB patients, which may lead to complications including deep vein thrombosis. Hence, Thrombolytic anticoagulant therapy and other preventions are necessary.
Rajasekaran et al indicated that spinal tuberculosis was considered to be the most common cause of severe kyphosis[29]. In our study, the kyphosis correction effect of posterior surgery was better than that of anterior and anterior-posterior combined surgery, and the loss rate of kyphosis correction in the anterior group was higher. The vertebral plate or articular process must be removed in posterior surgery, after complete lesions clear and bone graft, due to the effect of strong function of the pedicle screw and rod, and the kyphosis could be corrected convex. However, anterior surgery can clearly show the lesions, while the strength of the kyphosis correction was limited. As for anterior-posterior combined surgery, after the anterior lesions clear and the bone graft, the posterior approach is only for pedicle screw fixation assistance, and the strength of the posterior approach should not be too large after the anterior bone graft. To avoid the loosening and displacement of the bone graft, the posterior approach has advantages over the anterior-posterior combined and the anterior approach in kyphotic correction. Both the posterior approach and anterior-posterior combined approach have lower and upper pedicle screw fixation across the lesion level, resulting in small space loss after kyphosis correction, while the anterior approach alone is prone to correction loss due to partial absorption or loosening of bone graft, which is consistent with our follow-up results.
We consider that the treatment of thoracic lumbar vertebral tuberculosis including transthoracic or extrapleural approach of thoracic tuberculosis debridement and rib bone graft fusion, combined thoracoabdominal approach thoracic lumbar tuberculosis debridement and iliac bone graft fusion, as well as extraperitoneal lumbar tuberculosis debridement and iliac bone graft fusion have a curative effect in showing lesions, cleaning up the pus and sequestrum, with short operation time, less bleeding, short hospital stays and fewer complications. There is no difference between neurological function recovery and clinical healing rate among the three surgical approaches. Zhang et al reported that the posterior approach could achieve good results in the debridement and treat tuberculosis of the upper thoracic spine[20]. On the contrary, we suggested that the anterior approach should be preferred, which is suitable for patients with relatively good physical condition, lesions mainly located in the anterior middle column, the vertebral collapse that needs height reconstruction and anterior spinal cord compression. The posterior surgical approach could achieve good effect in the treatment of thoracolumbar tuberculosis, which is suitable for patients with vertebral appendix tuberculosis and posterior spinal cord compression, or those whose damage to the vertebral body was not serious and the pus was less. However, the posterior approach may destroy the structure of the vertebral body, resulting in the nidus to the back. The anterior-posterior combined approach is suitable for more serious cases with spinal instability, and difficult anterior fixation, the disadvantages of this approach are the large wound, intraoperative position change, long period of anesthesia and increasing rate of surgical complications.
Compared with the other two approaches, the anterior approach has more advantages and lower complications, which should be preferred. The posterior and anterior approaches have many disadvantages and high complications, and the anterior approach cannot be easily replaced.