The role of surgical treatment for spinal brucellosis remains poorly understood. It has been commonly perceived as the last resort in the complicated cases when the patients had persistent symptoms despite adequate antimicrobial therapy, septal abscess(15), vertebral collapse(8, 15), progressive neurological deficits(8) and spinal instability(8, 16). Moreover, few research studies investigated the surgical procedures in detail for treating spinal BS beyond therapeutic antibiotic regimens. Therefore, the surgical management has not been standardized. To provide the evidence to advance the clinical management of BS patients, this retrospective study compared the clinical efficacy of two different surgical approaches in patients with lumbar BS. The results showed that patients treated with one-stage anterior approach had less bleeding volume, shorter operation time and hospital stays, however, there were no distinct difference regarding clinical efficacy. Either method could achieve the postoperative outcome, and a personalized surgical plan should be recommended in real clinical practice.
The anterior approach has the advantage in lesion identification and differentiation from other adjacent tissues especially in the case of abscess. It enables the direct visualization of infected lesions and therefore can clear the lesion by using less time, especially in the removal of necrotic disc tissue and destroyed vertebrae to relieve the compression from the front of the spinal canal(17). The restoration of the anterior column through intervertebral bone grafting increased the spinal stability and repaired bone defects. More than 95% cases occurred in anterior or central column, and abscess happened predominately in the anterior part of the spine. In the present study, patients with one-stage anterior approach had less operating time and bleeding volume and shorter hospitalization days, compared to these with combined posterior and anterior approach, which indicated a relatively low surgical risk in anterior approach. One-stage approach therefore should be recommended in most of the LBS cases, especially in elder population, compared with combined posterior and anterior method.
However, anterior approach has been reported to have disadvantages including the possibility of vascular injury, the difficulty of dura repair, relatively high risks of intercostal muscle atrophy, pneumothorax, pneumonia, pleural effusion, chylothorax(18). Besides, in the cases with multi-level lesions, inaccessible anterior reconstruction and poor spinal stability, anterior approach only was not suitable. The combined posterior and anterior was therefore introduced. For example, Khaled Hassan et al, group has compared the anterior approach to posterior approach in patients with lumbar Pott’s disease and found that the anterior approach was less effective in kyphotic angel correction(19). Another study also showed the good agreement that posterior approach allowed better correction in patients with severe kyphosis (Cobb angle > 30°) (20). It also can be seen in this study that the Cobb angle in group B was more significantly improved than that in group A, and the present study had relatively larger sample size.
Although having more operative time and blood loss, posterior approach had the advantage in correcting kyphotic deformity through posterior pedicle screw fixation, maintaining the spinal stability and improving back pain(19), compared to anterior approach. Moreover, the posterior approach prevented the direct contact of internal fixation with infected lesions to avoid further inflammation. Each procedure has its own advantages and disadvantages. Although both methods caused damage to the spine structure, the immediate stability of the lumbar spine structure can be achieved by pedicle screw fixation, and the long-term anatomical stability can be achieved by the fusion of bone graft.
In terms of the surgical efficacy, two methods got primary healing, and the satisfactory recovery of wounds was observed at different time points after operation. This study also compared the VAS score, ESR and ODI of two groups regarding surgical efficacy assessment and the data demonstrated that two groups achieved good recovery at the relatively early stage without distinct difference. Both methods can remove the granulomatous tissue and necrotic lesions. Of importance, surgical procedure breaks the barrier of infected lesions, so that effective drugs can reach the lesion area, which indicated that surgery is necessary to be preformed in complicated cases or patients with ineffective treatment(21). The result was concordance with the earlier studies (19),(22). A systematic review including 25 studies compared the clinical efficacy of anterior approach, posterior approach and posterior approach combined with anterior approach and found that there was no significant difference among three methods, but posterior approach alone had less surgical risk.
And, in the selection of surgical procedures, individualized surgery should be recommended(19). This study suggested anterior approach only can be applied when patients with ≤ 2 involved vertebrae. In the cases where there is abscess compression or inflammatory granulation tissue wrapped around the nerve roots and dura mater, one-stage anterior approach is recommended. However, combine posterior and anterior approach is more suitable for patients with lesions in focal anterior column accompanying with paravertebral and prevertebral abscess or granuloma.
This study had some limitations. First, the sample size of this study is small. Second, the follow-up time is not long. Third, due to the different degree of segment destruction, the comparison before and after surgery for surgical efficacy assessment may bias. The findings of the present study should be confirmed in a prospective, case-control study with larger sample size in the future.