In this retrospective study we assessed the radiological and clinical outcome of the conservatively treated patients with AO A4, A3, and A1 TL fracture in relation to sagittal profile neurologically intact patients. To the authors’ knowledge, the current study is the first to investigate the sagittal balance and its effect on the clinical outcome in neurologically intact patients with AO A3 and A4 TL fracture, who were treated with early mobilization without bracing or casting.
Choosing the ideal management of TL burst fracture without neurological deficits is still challenging, and several studies have compared the operative and non-operative treatment of this fracture (11–17), there is no consensus between countries regarding the management of this type of fracture (18).
Different authors reported some benefits of the operative treatment, for instance, early mobilization, early hospital discharge, correction of the local kyphosis, and faster return to work but the patients were more susceptible to different complications, an increased risk of revision of the surgery, and subsequent greater overall healthcare costs. In this context, a high level of evidence demonstrated similar functional outcomes, lower complication rates, and less costs of the conservative treatment of neurologically intact patients with TL burst fracture (19–25).
After the management of acute painful vertebral fractures using balloon kyphoplasty Wardlaw D. et al (26) reported short term improvements in clinical outcomes compared to non-surgical treatment.
Regarding the conservative treatment, there is no consensus on the optimal course of conservative treatment modalities (27, 28). including analgesics, physiotherapy, bracing and/or casting, and mobilization. Giele B. et al (29) reported the lack of evidence of effectiveness of bracing in patients with traumatic thoracolumbar fracture in the current literature. Accordingly, Shamji MF. et al (30) reported a nonsignificant difference in the loss of the anterior vertebral body height between the group of patients with a customized thoracolumbar orthosis (TLSO) and the other group without bracing (TLSO: 12.5% ± 10.2% vs. no bracing: 11.9% ± 8.1%; p = 0.88) kyphotic progression (TLSO: 5.3 ± 4.4 degrees vs. no-brace 5.2 ± 3.6 degrees; p = 0.93), or clinical outcome differences at 6 months follow-up of neurologically intact patients with stable thoracolumbar burst fractures. Furthermore, they concluded that conservative therapy involving early mobilization without brace immobilization may be warranted. In this context, Jin Y. et al (31) reported a low-quality evidence of using Spinomed brace® in patients with sub-acute osteoporotic vertebral fractures. In our collective, all patients were treated without bracing or casting. The bed rest was minimized and early mobilization with physiotherapeutic aid was favored for all patients, as prolonged lying can lead to vascular complications, including orthostatic dysregulation, thromboembolic events, decubitus and pneumonia, all of which can lead to death (32). In all patients in both groups, the use of analgesic drugs was tailored on an individual basis. The correction of dose and class of drugs was performed on a day-to-day basis. The mean period of hospital stay of the patients in both groups was 5 days.
In previous reports, the results indicated that increasing residual deformity and alteration of the global sagittal balance can impact the clinical outcomes over the long term (33, 34). Koller et al (34) observed a strong correlation between the increase in the local deformity and the worsening of the clinical outcome in patients treated conservatively with bracing. Mayer et al (35) reported a superior outcome with restoration of the sagittal balance in surgical treatment of thoracolumbar spine fracture. In our study, we observed a worsening of the clinical outcome with the increase of local kyphotic changes and subsequent sagittal malalignment. Moreover, the group of patients with A3 and A4 TL fracture had a worse clinical outcome than the group of patients with A1 fracture at the last follow up. Our findings coincide with the previous reports that showed an increase of RKA of 13° in patients treated conservatively after thoracolumbar burst fracture (21, 23, 36–39). Other authors reported a mean final SKA of about 10° ± 3° after posterior-only, and 8° ± 1.8° after anterior-only treatment of burst fracture (11). Koller et al. (11) assessed the clinical and radiological long-term results in patients with thoracolumbar burst who were treated conservatively using a cast, they reported a final RKA of 4.7° ± 10.9 on average, while the SKA was 12.8° ± 5.8. Comparably, in our collective with A4 and A3 TL fracture the mean of SKA at the last follow up was 16.5 ± 5.8 and 19.3 ± 9.6, respectively.
A pathological sagittal profile is defined, therefore, by a combination of pathological values of all the spinopelvic parameters than just by a single pathological parameter. Abnormal sagittal balance is associated with many spinopelvic changes in attempt to compensate the imbalance. Reduction in the thoracic kyphosis, intervertebral hyperextension, retrolisthesis, pelvic back tilt, knee flexion and ankle extension were the main mechanisms described in the literature (32).
The correlation analysis in our study revealed a significant correlation between the age and the increase in the anterior shift of C7 plumb line with subsequent increase in pelvic retroversion following the increasing local kyphosis with subsequent worsening of the clinical outcome. This accords the previous finding presented by Vendatam et al. who demonstrated that the mean sagittal vertical axis (SVA) shifts forward in the ageing population, ensuing the loss of lumbar lordosis and the onset of symptoms in these patients (6).
In our study, we observed a significant negative correlation between the LL and the SKA as well as with follow up time. The progressive increase in the local kyphosis following the thoracolumbar fracture led to progressive loss in LL which affected the overall sagittal alignment and resulted in worse outcomes scores and greater self-reported pain and disability. This coincides with the previous results indicating worse disability amongst those with an increased degree of kyphosis in their lumbar spine in comparison to those with normal and lordotic lumbar spines (32). The progressive kyphotic changes may lead to progressive shift of the C7 plumb line anteriorly, as an attempt to restore the sagittal balance, the PT would increase in a mechanism described by Barrey et al (32) who reported the role of pelvic retroversion as the only mechanism in the pelvic area to compensate for the sagittal imbalance by bringing back the sacral plate and increasing the sacro-femoral distance, another step in the compensation for the sagittal malalignment is through the increase in knee flexion which explains the significant correlation we have noticed between the SVA and the SKA Delta, PT, LG, and FOA. This reflected the impact of the increasing local kyphosis on the local lordotic angle, as we found a negative correlation between the increase in the SKA FU and the RLA FU.