Treatment of lumbar tuberculosis with minimally invasive anterior lesion clearance combined with posterior fixation

Abstract

BACKGROUND

Spinal tuberculosis, a destructive extrapulmonary form, often causes severe deformity and neurological deficits. Surgical intervention aims to debride lesions, reconstruct stability, and correct deformities. This study evaluates a combined posterior fixation and minimally invasive anterior approach for lumbar tuberculosis.

AIM

To evaluate the clinical outcomes and radiological parameters of posterior internal fixation combined with minimally invasive anterior lesion clearance and bone graft fusion for the treatment of lumbar tuberculosis.

METHODS

Clinical data from 24 patients with lumbar tuberculosis who underwent posterior pedicle screw fixation combined with minimally invasive anterior lesion clearance were analyzed. The Cobb angle, visual analog scale (VAS) score, and Frankel classification were statistically assessed preoperatively and postoperatively. Complications and bone graft fusion were also recorded.

RESULTS

Wounds healed in the first stage in 22 patients; one patient developed a posterior incisional sinus tract, and one experienced postoperative tuberculosis recurrence. At the final follow-up, according to the Frankel classification, there were 1, 2, and 21 cases classified as grade C, grade D, and grade E, respectively. By the last follow-up, the Cobb angle, VAS score, and erythrocyte sedimentation rate had all decreased. Both X-ray and computed tomography images confirmed bone healing. The fusion time ranged from 3 to 9 months, with an average of 5.2 months.

CONCLUSION

Posterior pedicle screw fixation combined with minimally invasive anterior lesion clearance is an effective and safe treatment for lumbar tuberculosis.

Key Words: Lumbar tuberculosis; Pedicle screw fixation; Minimally surgery; Lesion removal

Core Tip: This study demonstrates that posterior pedicle screw fixation combined with minimally invasive anterior lesion clearance and bone graft fusion is an effective and safe treatment for lumbar tuberculosis. Clinical outcomes showed significant improvements in Cobb angle, pain relief (visual analog scale score), and neurological function (Frankel classification), with a high rate of first-stage wound healing (22/24 cases) and successful bone fusion (average: 5.2 months). While complications were rare (one case of incisional sinus tract and one recurrence), the combined approach offers minimally invasive advantages, including reduced soft tissue damage, faster recovery, and stable spinal reconstruction. These findings support its use as a viable surgical strategy for lumbar tuberculosis, balancing radical debridement, deformity correction, and functional restoration while minimizing morbidity. Further studies with larger cohorts are warranted to validate long-term efficacy.

INTRODUCTION

According to the Global Tuberculosis Report released by the World Health Organization, the number of newly diagnosed tuberculosis cases worldwide reached 10.8 million in 2023, continuing an upward trend compared to the previous year. Among these, cases in China accounted for approximately 6.8% of the global total, ranking among the top three worldwide[1]. Spinal tuberculosis is the most common form of extrapulmonary tuberculosis, primarily affecting the thoracic and lumbar spine. Severe cases can result in kyphotic spinal deformity and spinal cord dysfunction[2]. The goals of surgical treatment for spinal tuberculosis are to completely remove the lesion, relieve spinal cord compression, correct kyphosis, and restore spinal stability[3]. Recently, one-stage lesion clearance and bone graft fusion combined with internal fixation have gained increasing recognition among researchers[4]. However, the optimal surgical strategy for lumbar tuberculosis remains controversial. The anterior approach for lesion removal, combined with bone graft support and posterior internal fixation, can address the limitations of the standalone anterior or posterior approaches and promote postoperative recovery. Therefore, the combined anterior–posterior approach has become increasingly common in the treatment of lumbar tuberculosis[5]. The minimally invasive anterior incision measures 6-8 cm in length, which is shorter than that used in the traditional extraperitoneal approach. Blunt dissection along the muscle gap causes less damage to the soft tissue and abdominal wall musculature. During the operation, it is essential to expose the affected vertebra requiring debridement, as well as the adjacent vertebral bodies above and below, surrounding tissues, and segmental blood vessels. Postoperatively, patients experience reduced incision-related pain and faster recovery[6].

This retrospective case series analyzed 24 patients with lumbar tuberculosis who underwent one-stage posterior individualized pedicle screw fixation combined with anterior small-incision lesion clearance in our department between January 2016 and June 2018. The study aimed to evaluate the clinical outcomes of this surgical approach.

MATERIALS AND METHODS

Inclusion and exclusion criteria

The inclusion criteria were as follows: (1) Diagnosis of spinal tuberculosis confirmed by typical clinical manifestations, imaging studies, laboratory tests, postoperative histological examination, and pyogenic bacteria cultures; (2) Predominant involvement of the anterior spinal column, with evident abscess formation in the spinal canal, accompanied by significant pain and neurological symptoms; and (3) Patients with lumbar tuberculosis treated with posterior pedicle screw fixation combined with minimally invasive anterior lesion clearance.

The exclusion criteria were as follows: (1) Patients with active tuberculosis; (2) Patients with non-specific spinal infections or suspected other specific infections; (3) Patients with severe cardiopulmonary dysfunction who could not tolerate surgery or anesthesia; (4) Patients with non-lumbar tuberculosis; (5) Patients who did not undergo surgery; and (6) Patients with psychiatric or psychological disorders.

Surgical treatment

This retrospective study included 24 patients who underwent posterior internal fixation combined with minimally invasive anterior lesion clearance and bone graft fusion (Figure 1). The indications for surgery included: vertebral body destruction with necrotic bone, spinal instability, kyphotic deformity, neurological impairment, paravertebral abscess formation, severe low back pain or radicular pain, or failure of conservative treatment. The surgical approach for lesion removal was selected based on the extent of vertebral damage and the location of the abscess. The number of fixed segments and fixation strategy for the affected vertebrae were determined by lesion location, whether vertebral destruction was unilateral or bilateral and superior or inferior to the involved segment, and the feasibility of screw placement given interference from the lesion site.

Figure 1  Technical roadmap.

The patient was placed in a prone position, and a posterior midline incision was made, centered on the affected vertebra. The bilateral facet joints were exposed via a paravertebral muscle-splitting approach. Individual pedicle screws were inserted according to the degree of preoperative vertebral body destruction. The screw lengths ranged from 30 to 45 mm, and pedicle screws were implanted into one to two normal vertebral bodies above and below the lesion. Generally, in cases involving two vertebral bodies, two to three screws were inserted into the affected segments, and one normal vertebral body above and below received pedicle screws. For lesions involving three vertebral bodies, two to five screws were placed in the diseased segments, and one to two screws were implanted into the adjacent normal vertebrae. Kyphotic deformity was corrected using distraction and reduction through the internal fixation system. The patient was then rotated into a half-lateral position (Figure 2A). Centered on the diseased vertebra, an abdominal incision approximately 6-8 cm in length (Figure 2B and C) was made. Muscle fibers were separated bluntly, aligning the external oblique, internal oblique, and transversus abdominis muscles along the retroperitoneal space. The retroperitoneal margin was soaked in 0.9% sodium chloride solution to facilitate visualization of surrounding tissues. The abscessed tissue within the psoas major was debrided, followed by exposure of the affected vertebra. Necrotic intervertebral disc material, sequestrated bone, and purulent cavities were thoroughly removed (Figure 2D). A moderately sized autologous iliac crest bone graft was prepared and inserted into the defect (Figure 2E and F). The wound was irrigated, a streptomycin-impregnated gelatin sponge was placed in the operative area, and a drainage tube was inserted before final wound closure.

Figure 2 Key stages of combined approach lumbar tuberculosis surgery. A: Oblique surgical positioning; B: Lesion localization under C-arm fluoroscopy; C: Superficial position of the anterior small incision; D: Lesion debridement following exposure of tuberculosis; E: Harvesting an appropriately sized iliac graft; F: Intervertebral fusion following iliac graft implantation.

Postoperative administration

Postoperatively, depending on the amount of fluid drained, the drainage tube was typically removed within 48-72 hours, and antibiotics were administered for 2-3 days. One week after surgery, patients were generally allowed to ambulate with the assistance of a thoracolumbar brace. During the first three months, patients were advised to minimize physical activity. Systemic nutritional support and anti-tuberculosis therapy were continued after the operation. Diagnostic evaluations-including complete blood count, erythrocyte sedimentation rate, and liver and kidney function tests-were repeated every two to four weeks during the entire course of anti-tuberculosis treatment. Routine urinalysis was performed if streptomycin was administered.

All patients were followed up in the outpatient clinic. Frankel grading, visual analog scale (VAS) scores, and Cobb angles were recorded preoperatively, one week postoperatively, and at the final follow-up. To monitor neurological recovery and detect postoperative complications, X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) were performed every three months to assess lesion healing, bone graft fusion, and the integrity of pedicle screw fixation. The criteria for bone graft fusion proposed by Bridwell et al[7] were used to evaluate the fusion outcome. Grades I and II were considered indicative of successful bone graft fusion in this study.

Statistical analysis

Statistical analysis was performed using the SPSS version 20.0 software package. One-way analysis of variance (ANOVA) and repeated measures ANOVA were used to compare the data, and pairwise comparisons were conducted using the student-Newman-Keuls method. Categorical data were analyzed using non-parametric tests. A P value of < 0.05 was considered statistically significant.

RESULTS

This retrospective study included patients who underwent lumbar surgery at the Department of Spinal Surgery, Wuhan No. 1 Hospital; Wuhan Hospital of Integrated Traditional Chinese and Western Medicine; and Tongji Medical College, Huazhong University of Science and Technology, between January 2016 and June 2018. A total of 24 patients with lumbar tuberculosis-16 males and 8 females-were treated with posterior internal fixation combined with minimally invasive anterior lesion clearance and bone graft fusion. Patient ages ranged from 18 to 73 years (mean = 47.13, SD = 3.25), and the duration of disease ranged from 1 to 14 months (mean = 6.42, SD = 1.09). The clinical manifestations were as follows: all patients experienced varying degrees of lumbar pain, stiffness, flexion limitation, and restricted mobility. Seventeen patients (70.83%) presented with neurological symptoms of the lower limbs, such as numbness, weakness, diarrhea, or constipation. Seven patients (29.17%) exhibited typical tuberculosis-related symptoms, including low-grade fever, night sweats, and fatigue. Imaging studies revealed vertebral body and intervertebral disc destruction, along with paravertebral abscess formation, consistent with the diagnosis of lumbar tuberculosis. The average preoperative Cobb angle of kyphosis measured between the upper endplate of the superior vertebral body and the lower endplate of the inferior vertebral body was 15.21° ± 2.08° based on X-ray imaging. Laboratory examinations showed no significant abnormalities in hematologic indices or liver and kidney function tests. The average preoperative VAS score was 6.53 ± 1.14. Erythrocyte sedimentation rate ranged from 21 to 116 mm/h, with an average of 38.09 ± 1.17 mm/h (reference range: Adult males, 0-10 mm/h; adult females, 0-12 mm/h).

Anti-tuberculosis chemotherapy was administered with isoniazid (5-10 mg/kg/day), rifampicin (10 mg/kg/day), ethambutol (15 mg/kg/day), and pyrazinamide (25 mg/kg/day) for a duration of 2 to 4 weeks. For older patients with abnormal liver function or allergic reactions, individualized anti-tuberculosis regimens were formulated, and nutritional support was enhanced. Blood transfusion was provided to correct anemia when hemoglobin levels were below 10 g/L or serum albumin levels were below 30 g/L. The decision to proceed with surgery depended on tuberculosis symptomatology and erythrocyte sedimentation rate. The optimal timing for surgery was when symptoms were alleviated and body temperature was < 37.5 °C, hemoglobin was > 100 g/L, and erythrocyte sedimentation rate was < 60 mm/h.

A total of 24 patients were included in the study. The operative time ranged from 1.7 to 3.4 hours, with an average of 2.2 ± 0.3 hours. Intraoperative blood loss ranged from 390 to 1180 mL, with an average of 580.0 ± 64.2 mL. There were 14 cases of single-segment fusion and 10 cases of double-segment fusion. All patients were followed postoperatively for 6 to 36 months, with an average follow-up duration of 19.25 ± 8.32 months. Primary wound healing occurred in 22 patients. One patient developed a posterior incisional sinus tract, and one experienced postoperative recurrence of tuberculosis. No cases of sinus formation, incisional hernia, cerebrospinal fluid leakage, or spinal tuberculosis recurrence were observed among the remaining patients. All systemic tuberculosis symptoms (e.g., fever, night sweats, and fatigue) resolved. At the final follow-up, Frankel classification results were as follows: 1 patient with grade C, 2 with grade D, and 21 with grade E. The mean preoperative Cobb angle of kyphosis (15.21° ± 2.08°) was significantly reduced to 4.17° ± 1.58° at the final follow-up (P < 0.05). The preoperative VAS score was 6.53 ± 1.14 and improved to 2.12 ± 0.68 at the final follow-up (P < 0.05). The erythrocyte sedimentation rate decreased from 38.09 ± 1.17 mm/h preoperatively to 9.96 ± 0.86 mm/h postoperatively (P < 0.05) (Table 1). Both X-ray and CT images confirmed bone healing. The fusion time ranged from 3 to 9 months, with a mean fusion duration of 5.2 months (Figure 3).

Figure 3 Imaging progression of lumbar tuberculosis treatment. A: Preoperative computed tomography images showing vertebral bone destruction at T11, L3, and L4; intervertebral space destruction at L3/4; and paravertebral soft tissue swelling; B: Preoperative magnetic resonance imaging showing vertebral bone destruction at L3 and L4 and intervertebral space destruction at L3/4, with associated paravertebral abscess formation; C: Postoperative lumbar X-ray demonstrating intact spinal internal fixation without fracture or displacement, no bone graft migration, and satisfactory intervertebral fusion.

Table 1 Comparison of preoperative and postoperative indicators at the final follow-up, mean ± SD.

Item	Cobb angle (°)	VAS score	ESR (mm/h)
Preoperative	15.21 ± 2.08	6.53 ± 1.14	38.09 ± 1.17
Final follow-up	4.17 ± 1.58	2.12 ± 0.68	9.96 ± 0.86
F value	6.817	5.385	6.626
P value	0.016	0.030	0.017

VAS: Visual analog scale; ESR: Erythrocyte sedimentation rate.

DISCUSSION

The optimal surgical approach for lumbar tuberculosis remains a topic of ongoing debate, with various techniques offering distinct advantages and limitations[8]. The primary goals of surgical treatment are decompression of the spinal canal, thorough lesion removal, correction of spinal deformities, and reconstruction of spinal stability[9]. As the pathological damage caused by spinal tuberculosis primarily affects the vertebral body and intervertebral space, the anterior approach allows for direct visualization and complete lesion debridement, as well as anterior column support through bone grafting. When combined with posterior pedicle screw fixation, this technique may enhance the mechanical stability of the spine[10]. This, in turn, facilitates early postoperative mobilization and rehabilitation, which is why the combined approach is commonly applied in cases of lumbar tuberculosis. Patients with spinal tuberculosis often present with poor nutritional status and decreased vertebral bone mass. When anterior fixation is performed through the diseased vertebral bodies, the resulting mechanical strength is significantly lower than that achieved with posterior fixation and carries a higher risk of postoperative infection[11].

Multiple-level lumbar tuberculosis often requires long-segment fixation to maintain spinal stability. However, excessive internal fixation can reduce spinal mobility, accelerate adjacent segment degeneration, and increase patients' medical expenses[12]. To mitigate these drawbacks, short-segment pedicle fixation has emerged as a valuable approach in spinal orthopedics, as placing pedicle screws within the diseased vertebra can reduce the need for fixation across unaffected segments[13]. Preoperative imaging plays a pivotal role in surgical planning. Adequate imaging data provide a reliable basis for guiding pedicle screw fixation in diseased vertebrae[14,15]. Standard anteroposterior and lateral spinal X-rays are essential for assessing sagittal and coronal alignment parameters. Thin-slice CT scanning helps determine the presence of vertebral abscesses, cavities, or sequestrated bone. Additionally, MRI serves as a sensitive early diagnostic tool for spinal tuberculosis, enabling accurate identification of the number of affected vertebrae and the extent of paraspinal soft tissue involvement. Together, X-ray, CT, and MRI findings allow for a comprehensive preoperative assessment of vertebral body damage, support development of an individualized surgical plan, and help evaluate the feasibility of pedicle screw fixation in diseased vertebrae[16].

Several studies have reported that posterior vertebral internal fixation for multi-segment spinal tuberculosis can effectively shorten the fixation length while achieving favorable clinical outcomes[17]. According to Wang et al[18], if more than 50% of normal tissue remains in the anterior and middle columns after lesion removal, pedicle screw fixation can be applied to the affected vertebra. They recommend selecting pedicle screws only when the bone in the lateral third of the medial and posterior columns of the diseased vertebra is intact. If one of the three spinal columns is compromised, internal fixation may not be appropriate. In the present study, two patients exhibited severe destruction of the vertebral middle column and were therefore unsuitable for pedicle screw fixation. The remaining patients successfully underwent screw implantation. While posterior fixation provides mechanical stability, it may be insufficient for managing anterior abscesses located in areas such as the iliac fossa, groin, or buttocks. In such cases, supplemental anterior debridement may be necessary[19]. We believe that thorough preoperative imaging evaluation can significantly reduce the incidence of screw exposure following lesion removal.

Endoscopic techniques have gained increasing attention due to advantages such as reduced blood loss and faster recovery. However, their application is limited by small correction angles and restricted operative fields[20]. An alternative approach-a small anterior transabdominal incision (6-8 cm) offers a middle ground between open and laparoscopic surgery. The length of this incision, used for lesion debridement and bone graft implantation, is between that of conventional open incisions and purely laparoscopic procedures[21]. This technique does not require costly laparoscopic equipment, making it particularly suitable for low-resource settings. Furthermore, it avoids hand–eye coordination challenges by allowing direct visualization of the operative field. Compared with traditional open anterior lumbar surgery, the small anterior transabdominal incision-made along the direction of muscle fibers-causes less trauma to soft tissues and abdominal muscles. Intraoperatively, only the affected vertebra is exposed, minimizing damage to adjacent tissues and superior or inferior vertebrae[22]. Patients in this study experienced reduced postoperative incision pain, faster recovery, and a lower risk of incisional hernia. Although the visual field is somewhat restricted in smaller incisions, careful observation of critical anatomical structures-including blood vessels-remains essential. In this cohort, no vascular or visceral injuries were reported.

Overall, the small anterior abdominal incision was associated with less damage to the affected vertebrae, adjacent structures, and vascular anatomy; reduced postoperative pain; and expedited recovery. However, this study had several limitations. First, the sample size was relatively small. Second, there was no comparative evaluation involving randomized controlled trials. Third, the follow-up period was relatively short. Therefore, long-term, multicenter studies with larger sample sizes are necessary to objectively and accurately assess the clinical efficacy of this surgical approach.

CONCLUSION

This study demonstrates that individualized pedicle screw fixation, based on the degree of vertebral damage, combined with anterior small-incision lesion removal and bone grafting, is an effective and safe treatment for lumbar tuberculosis.