Population data
From January 2009 to September 2018, 23 patients with cervical spine tuberculosis who underwent surgery in our hospital were initially reviewed retrospectively. The diagnosis of tuberculosis was first made on the basis of medical history, clinical examination, laboratory results (erythrocyte sedimentation rate, ESR, C-reactive protein, CRP), radiologic imaging (X-ray, CT, and MRI), and drug response. A definitive diagnosis was made by histological examination and/or by polymerase chain reaction (PCR) of the resected tissue. The indications for surgery were severe kyphosis of the cervical spine, spinal instability, and neurologic deterioration. The inclusion criteria were as follows: (1) patients with lesions involving the lower cervical vertebrae (C3-C7), (2) patients who underwent debridement, autogenous bone grafting and instrumentation by an anterior-only approach, (3) patients with a definitive diagnosis of tuberculosis by pathological examination or PCR, and (4) patients with a minimum 2-year follow-up. The exclusion criteria were as follows: (1) damage to multiple cervical vertebrae; (2) tuberculosis lesions in the posterior column; and (3) loss to follow-up due to any reason. According to the different bone grafting methods, the patients were divided into the following two groups: the iliac bone graft group (Group A) and the structural manubrium graft group (Group B).
Preoperative examination and preparation
All the patients underwent anti-tuberculosis treatment by daily oral administration of isoniazid 300 mg, rifampin 450 mg, ethambutol 750 mg, and pyrazinamide 750 mg for at least 2–4 weeks preoperatively based on a previous study [11]. The malnourished patients were given nutritional support therapy to improve their preoperative condition.
Before surgery, the patients were informed about the various options for anterior cervical reconstruction: either (1) an iliac bone graft, (2) a structural manubrium graft, or (3) titanium mesh cages with an allograft. The advantages and disadvantages of each of these options were discussed extensively by the surgeon with the patients, and the patients made the decision and signed a consent form. Three-dimensional computed tomography (3D-CT) was performed to investigate the anatomy of the manubrium in all the patients who selected a sternal graft. In the workstation, the breadth, height and thickness of the manubrium were measured as described by Peng [12] (Fig.1). In the case of the presence of an extremely small or malformed manubrium, a substitutable procedure was considered to avoid pitfalls.
Surgical technique
All the operations were performed by one of the three senior surgeons at our institute. The surgery was divided into 3 steps. The first step was radical debridement of cervical spine tuberculosis lesions through the Smith-Robinson anterolateral approach. The height of the anterior gap was measured after washing the wound repeatedly. Step 2 of the surgery was harvesting a bone graft. The iliac bone harvesting technique was performed in Group A according to the method described in previous literature [4]. Structural bone was harvested from the manubrium in Group B as follows. A longitudinal or transverse 3-cm incision was made directly over the manubrium. Dissection was performed through the subcutaneous tissue to the periosteum. The anterior aspect of the manubrium was exposed to the medial limits of the sternoclavicular joints. A sternal block was harvested using piezosurgery, which was limited by the sternoclavicular joints laterally and 0.5 cm above the sternal angle cephalic end and below the suprasternal notch. Then, hemostasis was performed carefully by bipolar electrocoagulation. The defect of the manubrium was reconstructed with a gelatin sponge and the remaining morselized bone. Finally, a drainage tube was placed, and the incision was closed in layers.
The final step included grafting and fixation. An iliac bone autograft was used to reconstruct the anterior defect in Group A (Fig. 2), while a structural manubrium autograft was placed in the gap to reconstruct the anterior defect in Group B (Fig. 3). Then, a locking plate-screw system of appropriate length was used to achieve anterior cervical fixation. After hemostasis and washing were performed, a deep drainage tube was placed, and the incision was closed in layers.
Postoperative care
The drainage tube was removed when the volume of drainage was less than 50 ml/24 h. The patients were allowed to ambulate with the support of a neck brace after 3 days of surgery, which was used for 12 weeks. Anti-tuberculosis chemotherapy, which was the same as the preoperative regimen, was continued for 3 months postoperatively, followed by a regimen of isoniazid, rifampicin, and ethambutol for another 12–15 months [3].
Clinical evaluation and follow-up
Patient follow-up was performed at 3 months, 6 months, and 1 year postoperatively, and all the findings were recorded by the surgeon. The primary outcomes measured were the ESR, Cobb angle, VAS score, complications, and fusion rate. At each follow-up, lateral X-ray films or CT was performed. Fusion was assessed by the presence of bridging trabecular bone and the absence of radiolucency at the junction between the graft/cage and opposing vertebra [13].
Statistical analysis
Data analysis was performed using SPSS for Windows version 19.0 (IBM, New York, New York, USA). Paired t tests and independent-samples t tests were employed for intragroup and between-group comparisons of the continuous variables between the 2 groups, respectively. Categorical data were analyzed with the chi-square test. Values of P < 0.05 were considered to indicate significant differences.
