Introduction
Global aging is unstoppable and has resulted in a serious situation of osteoporosis [
1,
2]. Osteoporosis is characterized by increasing bone fragility and can easily lead to osteoporotic vertebral compression fractures (OVCFs) [
3], which have become a severe health problem because of high mortality and disability rate [
4‐
6]. Thoracolumbar vertebra usually refers to the T11-L2 spinal level, which is the most common location of OVCFs because of the anatomical characteristics [
7]. Nowadays, percutaneous vertebroplasty (PVP) has achieved good clinical results in the treatment of thoracolumbar OVCFs (TL-OVCFs) [
8,
9]. The classic puncture approach of PVP is conventional transpedicle approach (CTA). However, due to the anatomical specificity of the thoracolumbar pedicles, its inner inclination angle is smaller than that of the lower lumbar spine [
10]. Besides, a few pedicles are narrow due to anatomic variation, and its width is lower than normal value [
11]. Therefore, the anatomical characteristics of narrow pedicles not only greatly increase the puncture difficulty of PVP with CTA, but also cause poor distribution and inadequate injection of bone cement, which can lead to poor postoperative symptom relief. Basal transverse process-pedicle approach (BTPA) is performed at the base of transverse process, which enters the vertebral body through the transverse process and pedicle. The inclination angle of puncture (PIA) of BTPA is larger than that of CTA [
10], which can help the puncture needles to reach the center area of the vertebral body. Thus, the purpose of this study was to compare the clinical effects of two different puncture approaches on the treatment of TL-OVCFs with narrow pedicles.
Discussion
It has confirmed that the morphology and anatomical structures of the pedicles are crucial for puncture of PVP [
10]. In clinical practice, it is obvious that thoracolumbar narrow pedicles are not rare and more common in short women [
11], which increase the difficulty of puncture, operative time and trauma. Based on anatomical and mechanical characteristics, TL-OVCFs are different from the lower lumbar spine and prone to kyphosis and collapse with improper treatment [
16,
17]. Therefore, it is necessary to accurately understand the anatomical characteristics of narrow pedicles and important to explore the optimal puncture approach of PVP.
Good distribution of bone cement in PVP is required to achieve better clinical effects [
18]. However, it is closely related to the ideal puncture point and larger PIA [
10], which should be paid more attention to especially for TL-OVCFs with narrow pedicles. During the process of CTA, the puncture needles should be completely inside the pedicle to avoid enter the spinal canal. Due to the anatomical characteristics of TL-OVCFs with narrow pedicles, the PIA of CTA is significantly smaller [
11]. However, the puncture point of BTPA group was located at the base of the transverse process and more outward than that of CTA group. Thus, the PIA was significantly higher than that of the CTA, and it was easier to reach the central area of the damaged vertebra where stress was concentrated on.
Bone cement leakage is one of the common complications of PVP [
19], which can lead to biomechanical changes of injured vertebra and even spinal cord injury in severe cases [
20]. For TL-OVCFs with perivertebral wall damage, the incidence of soft tissue leakage, intravascular leakage and intervertebral disk leakage is significantly increased [
21,
22]. When PVP was performed with CTA, the channel of bone cement could not get close to the central area due to the smaller PIA. Then, the dispersion direction was from bilateral area of the vertebral body to the periphery during bone cement perfusion, which not only easily resulted in poor distribution of bone cement in the central area, but also significantly increased risk of bone cement leakage. Once bone cement leakage occurs during operation, surgeons often stop or reduce the injection of bone cement in order to avoid complications, which may lead to hypoperfusion of bone cement. However, in the BTPA group, the bone cement could reach the central area and diffuse from the central area to the periphery due to the larger PIA. Therefore, BTPA not only ensured the effective perfusion and facilitated the good distribution, but also reduced the risk of bone cement leakage.
The short-term purpose in the treatment of TL-OVCFs is to rapidly reduce pain and eliminate incapacitation [
9]. The results of this study showed that clinical indicators in both groups were obviously improved at 1 day postoperatively. However, the postoperative VAS and ODI of CTA group were worse than those of BTPA group. The reason was the difference of bone cement perfusion and distribution between the two groups. It has concluded that the analgesic effect of high-dose bone cement is better than that of low-dose bone cement [
23]. Besides, if bone cement is completely distributed in the fracture area, it can effectively strengthen the vertebral body and significantly relieve postoperative pain [
24]. Therefore, how to effectively inject high-dose of bone cement and distribute it in the fracture area during PVP are particularly important. In this study, because of the smaller PIA of CPA group, bone cement distribution was poor, especially the fracture area in the center of vertebral body. Whereas in the BTPA group, the distribution of bone cement in the central area was good due to the larger PIA. Therefore, the postoperative clinical indicators of BTPA group were better than those of CTA group after surgery.
The study has some imitations. First of all, this is a single-center, retrospective and controlled study, which need to be further validated by multicenter, prospective and randomized studies. Secondly, the sample size in this study is small and a larger-sample is needed to reduce errors. Finally, this study did not discuss the follow-up results, especially the comparisons of long-term complications. Therefore, we will conduct a large-sample size, multicenter controlled study and further compare the follow-up results to improve this study in the future.
Conclusion
In conclusion, both groups of PVP were safe and effective in the treatment of TL-OVCFs with narrow pedicles. However, BTPA group has the larger PIA, higher-dose bone cement perfusion, better bone cement distribution and lower bone cement leakage incidence, which can more effectively relieve pain after surgery.
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