Beneficial influence of single-stage posterior surgery for the treatment of lumbar brucellic spondylitis associated with spondylolisthesis

Pathological changes in brucellar spondylitis are primarily infectious in vertebrates and discites, with vertebral destruction, spinal instability, and spinal cord or nerve compression.^3,4,5,6,15. In recent years, with further research into the biomechanics of the spine, researchers have reasoned that surgery should be performed to remove lesions and rebuild the stability of the spine to relieve pain and promote recovery from pain. nerve function when antibiotic treatment is not enough to cure.^8,16,17. Tebet¹⁸ classified the causes of spondylolisthesis as isthmic, degenerative, and traumatic, specifically isthmus and degeneration. However, few studies have been done on the correlation between brucellar spondylitis and lumbar spondylolisthesis. There is also a lack of statistical data on the incidence of lumbar spondylolisthesis in patients with brucellar spondylitis. As we all know, the stability of the spine depends on joint support of the entire vertebral body, intervertebral disc, pedicle, ligament and surrounding tissues. In this study, 10 of the 16 patients (62.6%) were associated with an isthmus, with a high proportion, which may be one of the factors of lumbar spondylolisthesis. In further research, we may be able to perform correlation studies.

Clinically, various surgical methods for brucellar spondylitis include anterior, posterior or anterior and posterior debridement for bone graft fusion, and minimally invasive surgical methods, which have emerged in recent years.^{8,16,17,19,20}. Traditional surgical methods for brucellar spondylitis are combined anterior and posterior debridement, bone graft fusion, and instrumentation. This method has obvious drawbacks, including long operation time, change of body position during operation, and too complex operation^21.22. Therefore, more and more surgeons have chosen posterior debridement, bone graft fusion and instrumentation in recent years. This operation avoids the shortcomings of traditional operations and can significantly reduce the likelihood of recurrence^16,17,19. Na et al.¹⁶ showed that the posterior approach gives better correction of kyphotic deformity, less surgical invasiveness and fewer complications in patients associated with lumbar brucella spondylitis. Zhao et al.¹⁷ showed that the use of polyetheretherketone (PEEK) cages combined with one-step posterior debridement and instrumentation is feasible and safe in patients with lumbar brucella spondylitis. Chen et al.¹⁹ have shown that one-stage debridement, autogenous bone grafting and posterior instrumentation could represent an alternative treatment for lumbar tweezer spondylitis, and the efficacy and safety of these techniques are satisfactory. Surgical methods for lumbar spondylolisthesis are also diverse. The most classic surgical methods are posterior interbody fusion. The transforaminal and extreme lateral approaches have gradually developed, of which the oblique lateral approach, which has appeared in recent years, is posterior. The surgical core is reduction, decompression, fixation and fusion^23.24. We therefore adopted an a posteriori approach in this study.

Spinal stability needs a typical spinal sequence to be maintained, but there are still disputes over whether spondylolisthesis needs to be reduced and the degree of reduction. Pushed et al.²⁵ showed that the in situ fusion of the vertebral body of spondylolisthesis can also provide satisfactory clinical results, while the reduction of spondylolisthesis can lead to discomfort for patients. On the other hand, Dewald et al.²⁶ reported that complete reduction would lead to excessive nerve root traction. Therefore, partial vertebral body reduction of spondylolisthesis should be recommended. More researchers^27.28 suggested minimizing the vertebral body of spondylolisthesis, which will help restore the typical vertebral sequence and promote bone graft fusion. As postoperative recovery from brucellial spondylitis needs stability, we minimized the vertebral body of spondylolisthesis during the operation in this study.

However, the reduction is temporary and fusion of the bone graft is the ultimate goal. Using internal fixation instruments could maintain vertebral body reduction of spondylolisthesis, and fusion of bone graft would help spine stability²⁹. Dantas et al.³⁰ found that the posterolateral bone graft was not on the weight-bearing axis, which was prone to non-fusion of the bone graft or formation of the pseudo-joint. Through a follow-up study, Miyashita et al.³¹ found that pedicle screws and the interbody fusion cage can rebuild vertebral stability, effectively maintain intervertebral space height, reduce screw pressure, and reduce the incidence of pedicle screw fractures and loosening. Compared with simple debridement and bone graft fusion, instrumentation could make local stability conducive to bone graft fusion and promote lesion healing, with less postoperative complications and low recurrence rate.^8,17,32. Bone graft fusion is the basis of spinal stability. Therefore, internal fixation instruments are conducive to bone graft fusion. Said et al.³³ studied that patients with lumbar spondylolisthesis combined with isthmus, posterior interbody fusion could restore spinal stability, improve bone graft fusion, and have excellent long-term clinical effect. In this study, 62.6% of patients were complicated by an isthmus. Therefore, we adopted polyetheretherketone (PEEK) cages, interbody fusion, and pedicle screw fixation.

Postoperative follow-up showed that the mean rate of reduction of spondylolisthesis in 16 patients was (91.2 ± 6.7)% at 2 weeks postoperatively. The median rate of loss of reduction was 8.0 (5.0, 9.8)% 1 year postoperatively, indicating the beneficial influence of surgery. At the last follow-up, all the patients had an interbody fusion, no loosening, instrumentation fractures were found, and no patient had a recurrence, which means satisfactory clinical results. During follow-up, the clinical symptoms of 16 patients gradually improved and the inflammatory indices returned to normal. In addition, we found that VAS score, ODI index, ESR and CRP at 2 weeks and 1 year follow-up were significantly different from those before the operation, which showed a marked improvement in the condition. of the patient. In addition, the VAS score, ODI index, ESR and CRP at 1 year follow-up were significantly better than those at 2 weeks follow-up.

Our study had limitations: first, the number of patients with lumbar brucella spondylitis associated with lumbar spondylolisthesis was small and there was a lack of relevant research. Second, in this study, among the 142 patients with lumbar brucella spondylitis who improved after antibiotic treatment, none of them was associated with lumbar spondylolisthesis, so a control analysis did not could not be performed, which was related to the limited period of our retrospective analysis and the insufficient number of patients. Third, follow-up time was short. Thanks to our previous observation, most of the patients returned to normal after 1 year of operation, so we did a 1-year follow-up in this research. In future work, we will extend the follow-up period and perform statistical analysis of the relevant data. Therefore, further observations, research and clinical evaluations of cohort studies are needed.