Application of ASTLOF Scoring System in the Treatment of Acute Symptomatic Thoracolumbar Compression Fractures

Background: Osteoporotic vertebral compression fracture (OVCF) is a common injury in the elderly, often caused by low-energy injuries. Improper treatment will not only affect the stability and balance of the spine, but in severe cases will lead to neurological damage and increase the risk of death. This retrospective study aims to explore the principles of treatment of patients with the assessment system of thoracolumbar osteoporotic fracture (ASTLOF) in acute symptomatic thoracolumbar compression fractures when the ASTLOF score = 4 points. Methods: The clinical data of patients with acute symptomatic thoracolumbar compression fractures admitted from February 2018 to February 2020 were retrospectively analyzed. Each patient was evaluated according to the ASTLOF scoring system, and patients with ASTLOF score = 4 were selected, a total of 108 patients. According to different treatment methods, they were divided into 32 cases in the non-surgical treatment (NST) group and 76 cases in the surgical treatment (ST)group. The visual analog score (VAS), Oswestry disability index (ODI), the recovery of injured vertebral body height, and the incidence of adjacent segment fractures were used for comprehensive evaluation. Results: During the follow-up, the VAS score and ODI score showed that the early pain relief and functional improvement of the surgical treatment group were better than those of the conservative treatment group (P<0.05); the Cobb angle of the surgical treatment group was 3 months and 6 months after the operation, and the vertebral body was injured. The degree of improvement of margin height was better than that of the conservative treatment group (all P<0.05); in the surgical treatment group, 6 cases of adjacent vertebral fractures occurred after surgery, accounting for 7.89%, and 2 cases of the conservative treatment group had adjacent vertebral fractures, accounting for 6.25% There was no statistically signicant difference between the two groups (P>0.05). Conclusions: When the ASTLOF scoring system is used in the treatment of acute symptomatic thoracolumbar compression fractures, patients with ASTLOF score =4 should be treated with surgery in time, which can relieve pain early and quickly, perform functional exercises as soon fractures caused by severe violence; (cid:0) History of allergy to acrylic and bisphosphonate drugs; (cid:0) Pathological fractures. (cid:0) Bone mineral density(BMD): T value ≤ -3.5SD or T value> -2.5SD; (cid:0) those with coagulation dysfunction; (cid:0) those with infection all over the body or at the puncture site.


Background
Osteoporosis is a group of systemic skeletal diseases characterized by bone loss and destruction of bone microstructure, which leads to the decrease of bone strength, bone fragility, and increased risk of fracture [1]. The main complication of osteoporosis is osteoporotic vertebral compression fracture (OVCF) [2]. At present, there are more than 8.9 million osteoporotic fractures in the world every year, among which OVCF accounts for about 40% of all osteoporotic fractures [3,4]. At the same time, OVCF is also an important cause of morbidity and mortality in patients with osteoporosis. The traditional treatment strategy for hospitalized OVCF is non-surgical management (NSM), that is, bed rest, external brace xation, analgesia, and oral anti-osteoporosis drugs have achieved certain clinical effects [5].
However, the majority of OVCF patients are elderly patients and postmenopausal women. The patients' systemic function is decreased, and the traditional NSH fracture healing is slow, so they need to stay in bed for a long time, which can easily lead to infection, bedsore, pulmonary thrombosis, and progressive decalci cation and other related complications. Therefore, for the treatment of OVCF, the traditional treatment based on NSM gradually tends to be surgical treatment. Percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) that is, injection of medical bone cement or polymethylmethacrylate (PMMA) into the fractured vertebrae has been widely accepted as an effective pain relief method, and has become the conventional treatment for OVCF [6][7][8][9]. However, other studies have shown that PVP / PKP is similar to NSM in the conventional treatment of acute or subacute OVCFs patients, and does not show better clinical advantages. Therefore, how to evaluate the choice of conservative treatment or surgical treatment is a problem worthy of study [10][11][12]. After the ASTLOF was proposed and is widely used in clinical practice [13]. For osteoporotic vertebral compression fractures, the ASTLOF score of most patients was 4. According to the ASTLOF score system, surgery or conservative treatment can be selected, which makes clinicians have different opinions in treatment decisions. The clinical data of 108 patients with acute symptomatic OVCF who were admitted to our hospital from February 2018 to February 2020 were retrospectively analyzed to explore the treatment principles of patients with ASTLOF score = 4.

Inclusion and Exclusion Criteria
Inclusion criteria: Meet the WHO criteria for diagnosing osteoporosis, -3.5SD< T value ≤-2.5SD [14]; Low back pain (pain induced by changes in body position), VAS>5; After imaging examination (X, CT or MRI) was diagnosed as OVCFs; No symptoms and signs of the spinal cord and nerve root damage; Single-segment vertebral compression fracture; Age>55 years; The course of disease ≤6 weeks.
Exclusion criteria: Osteoporosis caused by drugs or medical diseases; Burst fractures caused by severe violence; History of allergy to acrylic and bisphosphonate drugs; Pathological fractures. Bone mineral density(BMD): T value ≤ -3.5SD or T value> -2.5SD; those with coagulation dysfunction; those with infection all over the body or at the puncture site.

General Materials
There were 108 cases (21 males and 87 females) with an average age of (71.62 ± 8.43) years (range, 55-92 years). There were 58 cases with slight trauma history, 14 cases with severe trauma history, and 36 cases without obvious trauma history. The main symptoms included low back pain, limited movement, and di culty in turning over. The time from symptom onset to admission was 1-42 days, with an average of (6.85 ± 2.36) days. Among them, there were 5 cases of T6-T10, 14 cases of T11, 20 cases of T12, 32 cases of L1, 18 cases of L2, 6 cases of L3, 9 cases of L4, and 4 cases of L5(Table1). There was no signi cant difference in age, sex ratio, BMD, and the vertebral segment between the two groups (P > 0.05). Before the start of the study, patients or their families were informed and signed an agreement. This study was reviewed and approved by the ethics committee of Honghui Hospital A liated to Xi'an Jiaotong University.

ASTLOF Scoring Method and Application
The ASTLOF score is based on the morphological changes of the injured vertebrae, MRI manifestations of the injured vertebrae, bone mineral density, and clinical manifestations (pain/neurological symptoms). The maximum total score is 8 points. See Table 2 for details. The total score can be used as the basis for selecting the treatment plan: total score ≤ 3 points, non-surgical treatment: total score = 4 points, according to the patient's vital signs to tolerate surgery, combined with the patient's desire for surgery and the quality of life requirements, Use non-surgical treatment or PKP/PVP; total score ≥ 5, use PKP/PVP, or open surgery that is fracture reduction and internal xation + injured vertebra PKP/PVP.

Therapeutic Technique
Non-operative treatment: Taking analgesics (celecoxib), rest in bed, wearing a brace to move down the ground after 4-6 weeks; cooperating with anti-osteoporosis drug treatment (calcium + vitamin D + calcitonin / zoledronic acid); preventing bed-related complications; starting rehabilitation treatment in the rehabilitation department of our hospital one week later (including hyperthermia treatment of injured vertebrae, interference current therapy or ultrasonic therapy); according to the patients with OVCFs Patients with pain tolerance, the back fascia extension, abdominal and hip extensors isometric contraction exercise rehabilitation exercise.

Evaluation index and Follow-up
The 108 patients with acute symptomatic osteoporotic vertebral compression fractures included in the study were collected with complete clinical and imaging data (X, CT, and MRI), and divided into non-surgical treatment group (n1=32) and surgical treatment group according to different treatment methods (n2=76). Follow-ups were performed at 1 week, 1 month, 3 months, 6 months, and 1 year after surgery. According to the visual analog score (VAS), the Oswestry disability index (ODI), the height recovery of the injured vertebral body, and the incidence of adjacent segment fractures, the e cacy evaluation criteria were used.

Statistical analysis
Statistical software SPSS 22.0 (IBM, Armonk, NY, USA) was used to analyze the data. The count data were expressed as a percentage and the chi-square test was used. The measurement data were expressed as mean ± standard deviation . Analysis of variance (ANOVA) was used for preoperative and postoperative comparison within groups, and the t-test of independent samples was used for intergroup comparison. The difference was statistically signi cant (P < 0.05).

VAS and ODI Scores
All patients were followed up. This group was followed up for 12.00 to 18.00 months, with an average of (13.42±4.11) months. There was no signi cant difference in VAS score and ODI score between the two groups before surgery (P>0.05), but the VAS score and ODI score in the surgical treatment group were signi cantly lower than the conservative treatment group at different time points after treatment, and the difference between the two groups was statistically signi cant ( P<0.05), but at the last follow-up, there was no signi cant difference between the groups (P>0.05). Table 3 shows the results of VAS scores of patients with different treatments, and Table 4 shows the results of ODI scores. The decreasing trend of VAS score after treatment of patients with different treatment methods is shown in Figure 1, and the decreasing trend of the ODI score is shown in Figure 2.
The VAS scores of patients with different treatment methods after treatment decreased compared with those before treatment, but the rate of decrease in VAS of the surgical treatment group was signi cantly higher than that of the conservative treatment group one week after treatment, the difference was statistically signi cant [(55.48±8.36)% vs (14.53±) 1.95)%, P<0.05]. Similarly, the rate of ODI reduction in the surgical treatment group was signi cantly faster than that in the conservative treatment group, and the difference was statistically signi cant [(36.22±1.57)% vs (4.96±0.15)%, P<0.05]. It indicates that the early and rapid pain relief effect of surgical treatment is signi cantly better than that of conservative treatment. The image of typical cases of surgical treatment is shown in Figure 3.

Cobb and Vertebral Height
There was no signi cant difference in the Cobb angle of kyphosis and anterior height ratio of the injured vertebral body between the two groups (P > 0.05). At 3 months and 6 months after the operation, the Cobb angle and anterior height of the injured vertebral body in the surgical treatment group were signi cantly improved compared with those before the operation, but there was no signi cant improvement in the non-surgical treatment group. The differences between the two groups were statistically signi cant (P < 0.05, Table 5).

Incidence of Adjacent Vertebral Fractures
The incidence of adjacent vertebral fractures in the two groups was followed up. There were 2 cases of adjacent vertebral fractures in the non-surgical treatment group, accounting for 6.25%, and 6 cases in the surgical treatment group, accounting for 7.89%. There was no signi cant difference between the two groups (P > 0.05, Table 6) Discussion OVCF is more common in elderly and menopausal women [15]. With the aging of the population, the mobility and the balance of ability decrease, resulting in a signi cant increase in the incidence rate [16]. According to statistics, about a quarter of postmenopausal women will have OVCF at least once in their life [17], and one-third of women and one-fth of men over the age of 50 will have a vertebral fracture in the rest of their lives [18]. OVCF is mainly caused by the low-energy injury. Bone formation and callus maturation are delayed due to the lack of bone mass, which is prone to delayed union or nonunion. When OVCF occurs, it will not only cause pain, deformity, dyskinesia, and other symptoms, but also lead to the decline of lung function and gastrointestinal problems, and increase the mortality rate [19]. available. Therefore, it is bound to affect the prognosis and clinical treatment of OVCF [22]. How to evaluate whether patients choose the non-surgical treatment or surgical treatment? If Denis classi cation, AO classi cation, or TLICS spinal injury score system are used, these classi cations are mainly for high-energy spinal injury, which is di cult to adapt to OVCF characterized by low-energy injury and osteoporosis [23,24]. Hao Dingjun et al. [25] proposed the assessment system of thoracolumbar osteoporotic fracture (ASTLOF). The scoring system consists of four parts: clinical manifestations of patients, morphological changes of injured vertebrae, MRI results, and bone mineral density. The classi cation combines imaging and clinical symptoms, provides a quantitative index for the treatment of OVCF and recommends the corresponding treatment scheme according to different scores. If the total score of ASTLOF is less than or equal to 3 points, conservative treatment is recommended; if the total score of ASTLOF is 4 points, both non-surgical treatment and surgical treatment are acceptable; if the total score of ASTLOF is more than 5 points, surgical treatment is recommended.
Many scholars have veri ed that the scoring system has high feasibility and repeatability, and can effectively guide the clinical treatment of thoracolumbar OVCF. According to the The author followed up the data of 108 patients with acute symptomatic thoracolumbar compression fractures with an ASTLOF score of 4 in our hospital. The results showed that the symptoms of low back pain and days activity of all patients in the non-surgical and surgical treatment groups gradually improved during different follow-up periods, and the VAS And ODI scores decreased gradually, and the difference was statistically signi cant compared with that at admission (P<0.05). However, the pain and functional recovery of the surgical treatment group were signi cantly better than those of the conservative treatment group (P<0.05). At the last follow-up, the overall VAS and ODI of the surgical group were signi cantly lower than those of the non-surgical group, indicating that the treatment options of the non-surgical and surgical groups were effective, but the surgery The treatment effect of the group is generally better than that of the non-surgical group, that is, PKP/PVP has the advantages of relieving pain and improving dysfunction in a short time. It shows that the selection of surgical treatment is reasonable and effective according to the ASTLOF score = 4 points. According to the cascade relationship of spinal fractures [26], patients with at least one minor vertebral fracture have a fourfold higher risk of subsequent vertebral fractures than those without fractures, which increases sharply with the number and severity of previous vertebral fractures [27]. Therefore, the patients with OVCF whose ASTLOF score is 4 points should be treated with surgery in time, which can relieve the pain quickly and recover the functional exercise as soon as possible, to reduce the incidence of complications such as falling pneumonia, urinary tract infection, muscle atrophy and weakness, bedsore and further loss of bone mass caused by long-term bed rest.
It has been reported that the risk of mortality associated with OVCF may be associated with spinal deformity, with a 1.14-fold increase in the kyphosis angle of age-adjusted SD [28]. Therefore, early correction of vertebral height and kyphosis Cobb angle is helpful to maintain the sagittal balance of the spine, reduce the incidence of lumbago, and reduce the risk of death associated with OVCF. When bone cement is injected into the injured vertebrae, the fracture site can not only regain mechanical stability, but also maintain the reduction state after hardening, and the height and Cobb angle of the injured vertebral body can be partially restored. At present, it is uncertain whether PKP / PVP increases the risk of vertebral fractures, especially adjacent vertebral bodies [29]. It has been reported in previous literature that the strength of the vertebral body and the physiological invagination of endplate are aggravated by injecting bone cement into injured vertebrae, which increases the pressure of the intervertebral disc, transfers the load to adjacent vertebrae, and increases the risk of fracture of the adjacent vertebral body [30][31][32]. In this study, the incidence of adjacent vertebral fractures in the surgical treatment group was 7.89%, which was not signi cantly different from that in the conservative treatment group (6.25%) (P > 0.05). However, due to the small number of cases in this study and the limited follow-up time, it is not clear whether the occurrence of vertebral fractures is the result of the natural course of osteoporosis or PKP / PVP surgery.

Conclusion
For patients with acute symptomatic OVCF whose ASTLOF score is 4, early surgical treatment should be given in time. It can not only relieve the pain quickly and perform the functional exercise as soon as possible but also effectively restore the height of the injured vertebrae and correct Cobb angle, which is conducive to reduce the incidence of related complications caused by long-term bed rest. However, whether it increases the risk of adjacent vertebral fractures still needs a large number of long-term follow-up studies. This study is a singlecenter retrospective study, the sample size is limited and multicenter, larger sample size and data statistics are The study was approved by the ethics committee of the Honghui Hospital A liated to Xi'an Jiaotong University, and all subjects obtained written informed consent.

Consent for publication
The subjects gave consent for any form of information about themselves to be published in the Journal of Orthopaedic Surgery and Research.

Availability of data and material
The dataset(s) supporting the conclusions of this article is included in the article.     Pre: pre-treatment; Post-3m: post-treatment 3 months; Post-6m: post-treatment 6 month s; NST: Non-surgical treatment; ST: Surgical treatment; Table 6 Comparison of the incidence of adjacent vertebral fractures in different treatments