Patient data
The inclusion criteria for this study were as follows: (1) Lesions limited to one or two adjacent segments without extensive TB abscess were included (in case of multiple segments being involved, only one or two vertebral bodies needed to be addressed surgically); (2) Severe or progressive neurological impairment; (3) Spinal instability or deformity, progressive aggravation of the trend; (4) Low back pain persists and medications are ineffective.
The exclusion criteria included individuals who had undergone lower lumbar surgery; a history of congenital scoliosis, deformity or ankyloses; and multilevel large psoas abscess or gravity abscess. The included patients were followed up for at least 5 years with complete data.
A total of 126 lower lumbar spinal TB patients were treated with one-stage posterior debridement, interbody fusion, and instrumentation from January 2004 to December 2014. Of them, 75 were male and 51 female patients. The average age of the patients at surgery was 47.4 ± 13.1 years. The number of lesion segments treated in these individuals was one in 24, two in 94, and three in 8 cases Three types of interbody bone grafts were performed in this study: 41 patients underwent autogenous and intervertebral bone grafts to get the anterior and middle columns reconstructed (Group A); 45 patients were treated with allogeneic bone graft for reconstruction (Group B); and the rest of the 40 patients were treated with titanium mesh cage bone grafting (group C).
The clinical symptoms the individuals presented included lower-back pain, weakness, low fever, and varying degrees of lower limb dysfunction. The Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values were found to be raised to varying degrees. Preoperative diagnosis was conducted on the basis of serological examination and imaging outcomes, comprising spinal radiographic films, computed tomography (CT), and magnetic resonance imaging (MRI), which exhibited vertebral bone destruction, narrowing or disappearance of intervertebral spaces, and cold abscesses. The neurologic examination was conducted as per the Japanese Orthopedic Association (JOA) score. The Oswestry Disability Index (ODI) was utilized to assess the quality of life. Back pain and radicular pain of lower extremity were estimated with the help of Visual Analogue Scale (VAS). University of California at Los Angeles (UCLA) grading scale (Table 1) was applied to evaluate the adjacent segment degeneration (ASD) on radiograph.
Table 1
UCLA grading scale for degeneration of the disc
Grade | Narrow of disc space | osteophyte | Endplate sclerosis |
I | − | − | − |
II | + | − | − |
III | ± | + | − |
Ⅳ | ± | ± | + |
The grade is based upon the most severe radiographic evident on plain radiographs |
+ present, − absent, ±either present or absent |
No significant differences among the three groups in the variables such as gender, age, diseased vertebrae number, preoperative ESR, CRP, JOA, ODI, VAS, and preoperative lordosis angles (Table 2) were found.
Table 2
Preoperative data of patients
| Group A | Group B | Group C | Statistical value | PA−B/PA−C/PB−C |
Gender (Male/Female) | 24/17 | 27/18 | 24/16 | χ2 = 0.025, P = 0.988 | -/-/- |
Age (years) | 47.6 ± 13.3 | 45.6 ± 13.6 | 49.4 ± 12.3 | F = 0.905, P = 0.407 | -/-/- |
Diseased vertebrae number | 1.9 ± 0.5 | 1.8 ± 0.5 | 1.9 ± 0.5 | F = 0.486, P = 0.616 | -/-/- |
During of symptoms (months) | 3.0 ± 1.2 | 3.3 ± 1.4 | 3.6 ± 1.5 | F = 1.378, P = 0.256 | -/-/- |
ESR (mm/h) | 68.4 ± 18.3 | 71.0 ± 16.0 | 69.9 ± 19.7. | F = 0.223, P = 0.800 | -/-/- |
CRP (mg/L) | 42.6 ± 10.5 | 46.8 ± 16.2 | 45.6 ± 15.8 | F = 0.968, P = 0.383 | -/-/- |
JOA | 18.8 ± 3.5 | 18.2 ± 3.8 | 18.3 ± 3.7 | F = 0.279, P = 0.757 | -/-/- |
ODI | 42.7 ± 5.9 | 43.6 ± 6.1 | 42.4 ± 7.2 | F = 0.387, P = 0.680 | -/-/- |
VAS | 6.9 ± 1.0 | 7.1 ± 1.1 | 6.8 ± 1.2 | F = 0.620, P = 0.540 | -/-/- |
Lordosis angle (°) | 16.1 ± 4.5 | 15.9 ± 4.5 | 16.3 ± 5.2 | F = 0.079, P = 0.924 | -/-/- |
Preoperative management
All patients were administered anti-TB drugs 2 to 4 weeks prior to the surgery, including isoniazid (300 mg/day), rifampicin (450 mg/day), and pyrazinamide (750 mg/day), and ethambutol (750 mg/day). They were strictly advised bed rest, strengthen their nutritional intake, and get anemia and hypoproteinemia corrected, simultaneously. Only when the symptoms of TB subside or disappear surgery may be conducted. During the anti-TB period, surgery may be performed in the presence of acute paralysis or progressive aggravation of neurological impairment, even if the ESR value does not decline.
Surgical method
The surgery was conducted with the patient lying in a prone position under general anesthesia.
Posterior midline incision was made considering the diseased vertebral body to be the center, in group C, exposing bilateral lamina, facet joints, and transverse processes. Pedicle screws were fixed in one or two vertebrae adjacent to the affected vertebrae, and short pedicle screws were also installed in the affected vertebrae if the pedicle screw channel was not destroyed by infection. A hemilaminectomy or laminectomy was conducted on the highly damaged side of the lesion segment. Then, the diseased vertebral bodies were exposed by removing the superior and inferior articular processes and pedicle. With the help of curettes of different angles the lesion tissues including the sequestrum, necrotic intervertebral disc, caseous necrosis, and pus was removed, through the transpedicular space, until blood exuded on the bone surface. Thereafter the silicone tube was carefully placed deep into the lesion along the sinus tract, and the pus was absorbed under negative pressure. The procedure was repeated on the other side of the lesion if required. Installation of permanent rods and exerting compression with the help of cantilever bending maneuver under vision to correct the deformity and scoliosis. Both the upper and lower bone surfaces of the vertebral body were repaired as bone graft beds. One or two ideally shaped titanium mesh cages filled with autogenous bone particles (from healthy lamina and spinous process) were used on both sides and allogeneic bone particles in the middle on the basis of the shape and size of the bone graft bed to reconstruct the anterior middle column. Moreover, autogenous and allogeneic granular bones were implanted between bilateral transverse processes, or a suitable allogeneic bone plate was placed between vertebral lamina. Streptomycin powder (1 g) and isoniazid (0.3 g) were applied in the lesion area, and the incision was closed in layers on placing a drainage tube.
Trimmed autogenous iliac and allogeneic bone blocks were implanted in the bone graft bed in groups A and B, respectively. The rest of the surgical procedures were the same as followed in group C.
Mycobacterium culture and histopathological examinations were carried out on the focus tissues of each patient during the operation.
Postoperative management
Routine antibiotics were administered and nutritional support provided post operation. The drainage tube was removed once the drainage volume collected in 24 hours was less than 30 ml. All the patients were continued to be administered with anti-TB drugs chemotherapy regimen post operation mentioned earlier for 12 to 18 months. Routine blood, liver function test, ESR and CRP evaluations were conducted to observe the adverse reactions and assess the efficacy of drugs. Following strict bed rest post operation for 4 weeks, patients were permitted to walk gradually with the help of an external brace for 6 months. Early rehabilitation training and physical therapy should be imparted to all patients to prevent thrombus and improve neurological function. Clinical and radiologic examinations were conducted once in every 3 months during the first year post operation in all patients and once in every 6 months thereafter.
Evaluating standard and statistical analysis
Operation period, intraoperative bleeding amount, and fusion period for each group of patients were documented. Bone healing was gauged as per the radiologic criteria of Lee et al through CT [10]. The following indexes were recorded preoperatively, postoperatively, and during the follow-up: (1) ESR and CRP; (2) neurological status according to JOA; (3) ODI and VAS; (4) lordosis angle; (5) ASD according to UCLA grading scale; and (5) surgery-related complications.
SPSS 20.0 software was used for performing statistical analysis. The measurement data of the three groups were compared by way of variance analysis first, followed by LSD⁃t test to compare each group when the value of P < 0.05. The numeration data were statistically analyzed with chi-square test. P < 0.05 was considered statistically significant.