23 patients with post-tubercular thoracic kyphosis were admitted to our department from January 2016 to January 2018. Diagnosis was made based on radiographic examination, laboratory tests and histopathology. This study was conducted with approval from the Ethics Committee of Our Hospital and was performed in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants. The indications for surgery were as follows: (1) low back pain refractory to conservative treatment; (2) being not able to lie down in dorsal position; (3) increasing neurological deficit. Patients with active infection and who cannot tolerate surgery due to poor cardiopulmonary function were excluded. Anteroposterior, lateral spine radiographs, CT 3-D reconstruction, Magnetic Resonance Imaging (MRI) were available for all patients (Fig. 2).
In all, 16 patients of whom (7males, 9 females; mean age 38.9 years) underwent the VCD technique. The mean Konstam’s angle[14] was 88.8° (ranging from 76° to 103°). Among the 16 patients, 6 patients underwent an initial debridement without fusion. Neurologic deficits were assessed according to the American Spinal Injury Association (ASIA) grading system as follows: ASIA E, 3 cases; ASIA D, 10 cases; and ASIA C, 3 case. Pain was assessed using the visual analogue score (VAS). Disability status was assessed using the Oswestry Disability Index (ODI). All patients’ radiological and clinical records were recorded preoperatively, postoperatively and during the last follow-up period. Operation time, blood loss, and osteotomy levels were noted. (Table 1)
Table 1
༎ Demographic and Clinical Data
Patient | Age | Sex | Osteotomy level | Instrumented levels | Operative time | Blood loss | Follow-up |
(min) | (ml) | (mon) |
1 | 32 | M | T8-T9 | T5-T8,T10-L1 | 250 | 420 | 29 |
2 | 41 | M | T7-T8 | T4-T7,T9-T12 | 260 | 580 | 33 |
3 | 50 | F | T5-L8 | T2-T5,T8-T11 | 240 | 450 | 32 |
4 | 37 | M | T9-T10 | T6-T9,T11-L2 | 220 | 480 | 31 |
5 | 35 | F | T5-T7 | T2-T5,T8-T11 | 200 | 430 | 30 |
6 | 29 | F | T6-T8 | T2-T5,T8-T11 | 210 | 410 | 32 |
7 | 32 | M | T8-T9 | T5-T8,T10-L1 | 220 | 400 | 28 |
8 | 54 | F | T10-T11 | T7-T10,T12-L3 | 240 | 450 | 35 |
9 | 32 | M | T5-T7 | T2-T5,T8-T11 | 230 | 480 | 29 |
10 | 43 | F | T7-T9 | T3-T6,T9-T12 | 250 | 450 | 32 |
11 | 36 | M | T6-T7 | T2-T5,T7-T10 | 210 | 530 | 34 |
12 | 41 | F | T5-T6 | T2-T5,T7-T10 | 200 | 450 | 31 |
13 | 40 | M | T7-T8 | T4-T7,T9-T12 | 220 | 520 | 36 |
14 | 36 | F | T7-T9 | T4-T7,T10-L1 | 240 | 470 | 27 |
15 | 46 | F | T5-T7 | T2-T5,T8-T11 | 210 | 430 | 29 |
16 | 38 | F | T6-T8 | T3-T6,T9-T12 | 230 | 520 | 34 |
Operative Technique
All surgeries were performed under monitoring of somatosensory-evoked potentials, transcranial motor-evoked potentials, and free-running electromyography. Under general anesthesia, the patient was placed prone on the operating table, and a standard posterior middle incision was made at the predetermined level. The spine was exposed by dissection lateral to the costotransverse joint at the thoracic level and the lumbar transverse process. The segmental vessels were coagulated using electric cauterization and hemostatic gauze. Pedicle screws (Weigao Orthopedic,Shandong, China)were then placed four levels above and below the damaged vertebral body by freehand technique. C-arm fluoroscopy was used to confirm the appropriate insertions.
Then, VCD was performed. The pedicle probe and drill were used to create and enlarge the relatively normal pedicle holes of the fused vertebras with both sides of the pedicles. These fused vertebras were treated as one targeted vertebra. Through the pedicle holes, the cancellous bone of the posterior half of osteotomy column was adequately removed using rongeur and curette. A high-speed drill was used to make thinning of the anterior cortex and lateral walls of vertebral body and linear fractures of the anterior cortex achieved using an osteotome. Then the spinal canal was opened laterally, and the posterior elements including the spinous process, bilateral lamina, transverse process, and the adjacent facet joints were removed. After removing the posterior cortical bone of the osteotomised vertebra, the kyphotic spine is corrected using gentle manual force stabilized by a temporary rod. The operating table and the position of the patient were adjusted for the correction.
During the correcting procedure, an anterior opening wedge was created and the middle column was preserved as the hinge. The posterior interlaminar fusion was completed over the fixed segments with residual autogenous bone. After confirmation of absent soft or bony compression, a drainage tube was placed in the surgical field, and the wound was closed in layer sequence.
Statistical analysis
All statistical analysis was performed with SPSS v19.0 software (SPSS Inc., Chicago, Illinois). Students’ t-test was used for all analyses, and a p-value < 0.05 was considered statistically significant.