The effect of the size of pedicle screw on the long-term radiological and clinical results of short-segment posterior instrumentation in the management of thoracolumbar vertebral fractures

Anıl Murat Öztürk; Onur Süer; Selahaddin Aydemir; Bünyamin Kılıçlı; Ömer Akçalı

doi:10.5152/j.aott.2024.23056

. 2024 Jan 1;58(1):20–26. doi: 10.5152/j.aott.2024.23056

The effect of the size of pedicle screw on the long-term radiological and clinical results of short-segment posterior instrumentation in the management of thoracolumbar vertebral fractures

Anıl Murat Öztürk ¹, Onur Süer ^2,^✉, Selahaddin Aydemir ³, Bünyamin Kılıçlı ¹, Ömer Akçalı ³

PMCID: PMC11059949 PMID: 38525506

Abstract

Objective:

It was aimed at evaluating the effect of the size of the pedicle screw placed on the fractured vertebra on the long-term radiological and clinical results of short-segment posterior instrumentation applied in the surgical treatment of thoracolumbar vertebral fractures.

Methods:

This retrospective study included 36 patients who underwent short-segment posterior instrumentation surgery for a single-level thoracolumbar (T11-L2) fracture between January 2015 and March 2021. The patients included in the study were divided into 2 groups according to the size of the pedicle screw placed in the fractured vertebra (group A: intermediate screw 4.5 mm, ≤35 mm + less than 50% of the vertebral corpus length, m/f: 13/4, n: 17, age: 36.5; group B: intermediate screw 5.5 mm, ≥40 mm + more than 70% of the vertebral corpus length, m/f: 11/8, n: 19, age: 42.6). All patients were periodically evaluated clinically and radiologically. Vertebral compression angle (VCA), anterior and posterior vertebral body height (ABH-PBH), intraoperative parameters (instrumentation time and intraoperative fluoroscopy number), and complications were compared between the 2 groups.

Results:

Both groups were comparable with respect to age, sex, level of injury, AO classification, mechanism of injury, and American Spinal Cord Injury Association impairment scale. Restoration of VCA and vertebral corpus heights was achieved sufficiently in both groups after operation (P < .0001). There was no significant difference between the 2 groups in terms of early postoperative VCA, VCA measured at final follow-up, or loss of correction in VCA. At the last follow-up, PBH was statistically significantly better preserved in group B (P = .0424). There was no difference between the 2 groups in terms of operation time and the number of intraoperative fluoroscopies. Implant failure was observed in 1 patient in group A.

Conclusion:

This study has revealed that using a long, thick pedicle screw placed in the fractured vertebra can better preserve the PBH at the final follow-up. No correlation was found between the size of the intermediate screw and the preservation of the correction in the postoperative vertebral heights and VCA during the follow-up.

Level of Evidence

Level III, Therapeutic Study.

Keywords: Fractured vertebra, Intermediate screw, Posterior instrumentation, Short-segment fixation, Thoracolumbar fractures

Highlights

There is no consensus on the ideal length and diameter of pedicle screws for treating thoracolumbar vertebral fractures. This study aims to evaluate how the size of the pedicle screw, when placed in the fractured vertebra, affects long-term outcomes in short segment posterior instrumentation.
The results showed no correlation between the size of the intermediate screw and the preservation of the correction in the postoperative vertebral heights and vertebral compression angle (VCA) during the follow-up. Moreover, there was no statistical difference in operation time and intraoperative fluoroscopy numbers in group A compared to group B.
Thick pedicle screw placed in the fractured vertebra can better preserve the posterior body height (PBH) at final follow-up. Moreover, a short and thin pedicular screw in a fractured vertebra in short-segment posterior fixation provides radiological outcomes comparable with a long and thick pedicular screw.

Introduction

Thoracolumbar fractures (T11-L2) are the most common spinal injuries.¹ The transition from the less mobile thoracic spine with its associated ribs and sternum to the more dynamic lumbar spine subjects the thoracolumbar region to significant biomechanical stress. Although the treatment is still controversial, anterior, posterior, and combined approaches are used in patients for whom surgery is planned. The posterior approach provides a safe operation that allows 3-column fixation, is free from the complications of the anterior approach, and reduces operative time and blood loss.^2-4

Although posterior long-segment instrumentation (consisting of pedicular screws, 2 or 3 levels above and below the fractured vertebra, with interconnected rods) provides more stable fixation and less correction loss on follow-up, it reduces the number of mobile vertebrae because it involves multiple segments and causes longer operative time and more blood loss. Posterior short-segment instrumentation (consisting of pedicular screws, 1 level above and below the fractured vertebra, with interconnected rods) allows for shorter operative time and less blood loss, but adverse effects such as loss of correction and inadequate recovery of the spinal canal have also been reported.^5-7 However, numerous biomechanical and clinical studies have shown that fixation of fractured vertebrae with pedicle screws can significantly improve spinal stability and reduce stress.^8-13 With the inclusion of the fracture level in short segment fixation of the fractured vertebra, the correction of kyphosis and the preservation of sagittal alignment similar to long segment instrumentation have been demonstrated.¹²

In the literature, many different techniques have been used in fractured vertebrae, such as shorter size screws, equal size screws, polyaxial intermediate screws, and monoaxial intermediate screws compared to screws in non-fractured vertebrae.^14-17 There is no consensus on what size and type of spacer screw is best. In the surgical treatment of thoracolumbar vertebral fractures, although the mobile segment is preserved with short segment fixation, the most important problem is the loss of the reduction obtained in the surgery in long-term follow-ups. With the use of intermediate screws in the surgery, the rigidity of the system can be increased, and reduction loss can be prevented in long-term follow-ups. However, there is no consensus in the literature regarding the screw size to be placed in the fractured vertebra. In addition, the effect of the size of the screw placed on the fractured vertebra on the results was not investigated.

The purpose of this study is to evaluate the effect of the size of the pedicle screw placed on the fractured vertebra on the long-term radiological and clinical results of short-segment posterior instrumentation applied in the surgical treatment of thoracolumbar vertebral fractures.

Materials and methods

Study design and patient characteristics

Our study design is retrospective. It was performed on patients who were operated on with short segment posterior instrumentation plus an intermediate pedicular screw in fractured vertebrae due to thoracolumbar vertebral fracture in the Departments of Orthopedics and Traumatology in 2 university hospitals in the same providence since the approval date of the Ethics Committee of Ege University (Approval No: 23-3T/44). The informed consent of the participants was obtained before research procedures started.

Thirty-six patients with single-level thoracolumbar(T11-L2) fractures between January 2015 and March 2021 were included in this retrospective study. Those who had previous back surgery, a previous fracture diagnosis in the same region, two-level fractures or more, osteoporosis, a rheumatologic disease that would cause problems with bone quality and healing, insufficient follow-up time, and insufficient radiological images were excluded from the study. The patients were divided into 2 groups according to the size of the pedicle screw placed in the fractured vertebra (group A: intermediate screw 4.5 mm, ≤35 mm + less than 50% of the vertebral corpus length, m/f: 13/4, n: 17, age: 36.5; group B: intermediate screw 5.5 mm, ≥40 mm + more than 70% of the vertebral corpus length, m/f: 11/8, n: 19, age: 42.6) (Figure 1). We recorded the demographic and clinical characteristics of the patients, including age, sex, level of injury, AO (Arbeitsgemeinschaft für Osteosynthesefragen) classification, mechanism of injury, and American Spinal Cord Injury Association (ASIA) impairment scale (Table 1). The clinical and radiological data obtained in the evaluations were compared between the 2 groups.

Figure 1. — The blue line indicates the screw length in the fractured vertebrae corpus, and the red line indicates the corpus length of the fractured vertebrae in lateral view. A 4.5 mm, ≤35 mm pedicular screw was used in group A and the blue/red lines length proportion was less than 50% (A). Whereas a 5.5 mm, ≥40 mm pedicular screw was used in group B, and the blue/red lines length proportion was ≥70% (B).

Table 1.

Demographic and clinical characteristics of the 2 groups

	Group A	Group B	t or χ ²	P
N	17	19	3	3
Age	36.5 ± 12.8 (minimum: 20, maximum: 63)	42.6± 7.8 (minimum: 26, maximum: 54)	1.7641	.0867
Gender Female Male Mechanism of Injury Motor vehicle Falling	4 13 3 14	8 11 5 14	1.1699 0.6103	.2502 .5457 3
Location of The Fracture T11	0	1	1.3735	.1786
T12 L1 L2	4 7 6	7 7 4	3	3
AO Classification A A1 A2 A3 A4 B B1 B2 B3 C	11 1 1 2 7 6 0 6 0 0	15 2 1 3 9 4 0 4 0 0	0.9375 3	.3551 3
ASIA scale A B C D E	0 0 0 2 15	0 0 0 3 16	0.3394 3	.7364 3
Follow-up time (months)	18.82 (12-48)	21.05 (12-36)	0.7471	.4601

Open in a new tab

No statistical differences were seen in age, gender, mechanism of injury, location and AO classification of the fracture, pre-op ASIA scale of the patients and follow-up time among the groups.

ASIA, American Spinal Cord Injury Association; IS, intermediate screw.

Assessment of the parameters among groups

The intraoperative parameters (instrumentation time and intraoperative fluoroscopy number) were recorded during the surgery. Preoperative computed tomography (CT) and postoperative plain radiograph images (anteroposterior and lateral standing radiographs) were obtained and evaluated with the program Sectra (Sectra AB, Linkoping, Sweden) by 3 orthopaedic surgeons involved in the research. Radiological images were evaluated in a blinded fashion. Plain radiographs of the thoracolumbar spine directly after trauma, immediate postoperative, and at the last follow-up (mean 20 months, range of 12-48 months) were compared retrospectively. Based on the radiographs, the fractures were classified according to the AO classification using the available preoperative CT.¹⁸ Additionally, the following measurements were performed using plain radiographs and preoperative CT.¹⁹

The percentage of the length of the pedicle screws in the vertebral body to the length of the vertebral body was calculated in the lateral view (Figure 1).
Vertebral compression angle is defined as the angle between the lower and upper borders of fractured vertebra (Figure 2A-C, Figure 3A-C).
Anterior vertebral body height (ABH; measured from the anterosuperior corner of the vertebra to the anteroinferior corner) (Figure 2D-F, Figure 3D-F)
Posterior vertebral body height (PBH; measured from the posterosuperior to posteroinferior corner) (Figure 2D-F, Figure 3D-F).
Anterior vertebral body compression percentage (ABH/PBH ratio).

Figure 2. — Vertebral compression angle measurement preoperative (A), early postoperative (B) and 1-year follow-up (C) in group A. Anterior body height and posterior body height measurements preoperative (D), early postoperative (E) and 1-year follow-up (F) in group A.

Figure 3. — Vertebral compression angle measurement preoperative (A), early postoperative (B), and 1-year follow-up (C) in group B. Anterior body height and posterior body height measurements preoperative (D), early postoperative (E), and 1-year follow-up (F) in group B.

Surgery

All surgeries were performed when the general condition of the patients was suitable, all the radiological examinations were performed, and consultations were finished in the emergency department (<48 hours). All patients underwent surgery for short-segment posterior instrumentation under general anesthesia utilizing the posterior midline approach, centered on the fractured vertebra. In all patients, intermediate screws were placed in the fractured vertebra at surgery. All surgeries were performed by 2 experienced surgeons (O.A. and A.M.O.) using a similar approach and implants. The surgeons were free to choose the size of the intermediate screw placed in the fractured vertebra based on their own surgical experiences. During the surgery, 4.5 mm, ≤35 mm pedicular screws were preferred to be placed bilaterally on the fractured vertebra by surgeon A.M.O. (group A). If the length of the pedicular screw inserted on fractured vertebrae during the operation with C-arm fluoroscopy control exceeded 50% of the vertebral corpus length, it was replaced with a smaller screw. On the other hand, 5.5 mm, ≥40 mm pedicular screws were preferred to be placed bilaterally on the fractured vertebra by surgeon O.A. during the surgery (group B). To determine the screw length, a tiny spherical tip probe was used to evaluate the length of the entrance hole. With the C-arm fluoroscopy control, it was observed that the length of the screw placed in the fractured vertebra was approximately more than 70% of the vertebral corpus length. Although there is no information in the literature about the use of the ideal length for the intermediate screw in the fractured vertebra, surgeons’ thoughts when making their choices are: A.M.O. believes that smaller pedicular screws placed on the fracture line will still contribute to the rigidity of the system, even though placing a thick and long pedicular screw will increase the rigidity of the system more. A.M.O. preferred to insert a smaller and thinner screw due to the instability of the fracture line caused by the damage to the posterior element screw, which can be inserted more easily, and the challenges of measuring the screw length in extensively comminuted fractures using a small spherical tip probe. Additionally, despite the lack of evidence in the literature, he opted to implant smaller, thinner pedicular screws in all of his patients because he believed that lengthy, thick screws might separate the fragments, especially in heavily comminuted fractures (Figures 4 and 5). Besides, with longer screws reaching to the anterior cortex, no anterior support would be provided to the fractured vertebra due to the upper endplate and anterior column already being disturbed. According to O.A., the reason for preferring longer and thicker pedicular screws is that the large bone defect developed within the fractured vertebra following height restoration has been believed to be a major cause of complications like correction loss and failure of the hardware, and these are most frequently observed in short-segment fixation. The lengthy and thicker pedicular screw at the fracture site could generate a mass effect, protecting the vertebra from collapse (Figure 6). It could be helpful in providing support for the anterior column, which is crucial to the construct’s durability.

Figure 4. — In the case who was operated with a thicker and longer pedicular screw, the intermediate screw came between the fractured fragments, causing the vertebral fracture fragment (white arrow) to separate (A-D).

Figure 5. — The intermediate screw causes the anterior fragment to be pushed anteriorly (white arrow) in highly comminuted fracture (A-C).

Figure 6. — The 5.5 mm, 45 mm pedicular screws were inserted at the fracture site L1. Following optimal fracture restoration with short segment fixation, the intermediate screw may provide a mass effect under the fractured upper endplate, so might be helpful in preventing the vertebrae from collapse (A,B).

Statistical analysis

Data was analyzed using Student’s t independent sample test, chi-squared test, and Friedman test. P < .05 was considered statistically significant. The data is presented as mean ± standard deviation. Statistical analyses were performed using Statistical Package for Social Science Software, version 23.0 (IBM SPSS Corp.; Armonk, NY, USA).

Results

When both groups were compared, there was no statistical difference with respect to age, sex, level of injury, AO classification, mechanism of injury, and ASIA impairment scale between the groups (Table 1).

Independent measurements by all 3 physicians revealed full compliance when radiological evaluations for all patients were compared.

The results of the radiological evaluations are shown in Table 2. Restoration of VCA and vertebral corpus heights was achieved sufficiently in both groups after operation (P < .0001). Restoration of PBH was significant in Group B at the last follow-up (P = .0424). There were no significant differences in preoperative VCA, postoperative VCA, follow-up VCA, correction loss VCA, preoperative ABH, postoperative ABH, follow-up ABH, correction loss ABH, preoperative PBH, postoperative PBH, correction loss PBH, preoperative ABH/PBH ratio, postoperative ABH/PBH ratio, and follow-up ABH/PBH ratio among the groups (P = .6796, P = .2612, P = .9133, P = .1352, P = .0738, P = .3265, P = .2432, P = .7593, P = .1551, P = .0848, P = .9498, P = .4364, P = .6066 and P = .9596, respectively).

Table 2.

Radiological and intraoperative parameters of 2 groups.

	Group A	Group B	t	P
N	17	19	3	3
Preoperative VCA (°)	11,66 ± 5.87	12.43 ± 5.24	0.4166	.6796
Postoperative VCA (°)	6.30 ± 2.98	7.77 ± 4.47	1.1427	.2612
Follow-up VCA (°) Correction loss VCA (°)	8.21 ± 4.98 1.9 ± 2.8	8.38 ± 4.45 0.63 ± 2.18	0.1097 1.5301	.9133 .1352
Preoperative ABH (mm)	19.14 ± 4.41	21.65 ± 3.73	1.8447	.0738
Postoperative ABH (mm)	26.40 ± 4.31	27.99 ± 5.16	0.9955	.3265
Follow-up ABH (mm) Correction loss ABH (mm)	25.24 ± 4.43 1.6 ± 2.48	27,13 ± 5.04 0.85 ± 3.25	1.1876 0.3089	.2432 .7593
Preoperative PBH (mm)	25.92 ± 4.27	27.61 ± 2.55	1.4541	.1551
Postoperative PBH (mm)	30.65 ± 4.12	32.93 ± 3.58	1.7755	.0848
Follow-up PBH (mm) Correction loss PBH (mm)	30.47± 3.80 0.17 ± 2.13	32.85 ± 2.97 0.23 ± 2.95	2.1084* 0.0634	.0424* .9498
Preoperative ABH/PBH ratio Postoperative ABH/PBH ratio Follow-up ABH/PBH ratio Operation Time (min) Fluoroscopy number (n)	0.73 ± 0.1 0.85 ± 0.09 0.82 ± 0.11 101.47 ± 12.7 14.35± 1.77	0.77 ± 0.16 0.82 ± 0.15 0.82 ± 0.13 108.16 ± 11.2 15.42 ± 1.68	0.7876 0.5198 0.0511 1.6774 1.8608	.4364 .6066 .9596 .1026 .0714

Open in a new tab

Posterior body height was significant in group B at the last follow-up (P = .0424). There were no significant differences in preoperative VCA, postoperative VCA, follow-up VCA, preoperative ABH, postoperative ABH, follow-up ABH, preoperative PBH, postoperative PBH, preoperative ABH/PBH ratio, postoperative ABH/PBH ratio and follow-up ABH/PBH ratio among the groups. There was no statistical difference in operation time and intraoperative fluoroscopy numbers in group A compared to group B.

ABH, anterior body height; IS, intermediate screw; PBH, posterior body height; VCA, vertebral compression angle;

The percentage of the length of the pedicle screws in the vertebral body to the length of the vertebral body was less than 50% in group A, whereas ≥ 70% in group B.

There was no statistical difference in operation time and intraoperative fluoroscopy numbers in group A compared to group B (P = .1026 and P = .0714, respectively).

Implant failure was observed in 1 patient in group A.

Discussion

There are no evidence-based treatment guidelines for the appropriate surgical approach and instrumentation technique in the treatment of thoracolumbar vertebral fractures.^14,20-23 Posterior pedicle fixation is the most common surgical treatment for thoracolumbar fractures because it offers low morbidity, short operative time, an easier learning curve, and rigid fixation through 3-column fixation.^2-4,24 The fixation of pedicle screws with short or long segments in the treatment of posterior approach fractures remains controversial.²⁵ Short-segment pedicle screw fixation, in which 1 vertebra is fixed above the fracture plane and 1 below, has become the most common method in the treatment of unstable thoracolumbar fractures.⁴

After posterior short-segment instrumentation, negative consequences such as loss of correction and implant failure have been reported.^5-7 Anterior column support or long-segment posterior instrumentation is recommended to eliminate these problems. However, in a series of biomechanical studies initiated and subsequently performed by Dick et al. in 1994, the insertion of screws into the fractured vertebra has been shown to stabilize the fracture and reduce loss of correction.^8-12,26 The advantages, such as protection of the segment, have made this technique interesting. The clinical application of the pedicle screw in the fractured vertebra for thoracolumbar fractures is becoming a controversial issue due to the limited evidence available. Pedicle screw fixation with an intermediate screw in the fractured vertebra improved biomechanical stability and resulted in better reduction, less loss of correction, less instrument failure, and comparable or better clinical outcomes.^12,22

In posterior short-segment instrumentation, fixation of the fractured vertebra with a pedicle screw has been shown to help stabilize the fracture, and kyphosis has not changed at follow-up. Behairy et al demonstrated good correction of segmental kyphosis, vertebral body curvature, and vertebral height loss by inserting a pedicle screw into the fractured vertebrae with short segment fixation.²⁷ Other clinical studies by Dobran et al and Guven et al demonstrated that the fracture plane should be included in short-segment fixation of the fractured vertebra, the correction of kyphosis, and the maintenance of sagittal alignment, like long-segment instrumentation.^13,14 In all 3 studies, the size of the interfragmentary screw showed a homogeneous distribution, demonstrating that the technique can provide and maintain sagittal correction.

Another topic of discussion is the size and type of screw that is inserted into the fracture line. If we look at the literature, in fractured vertebrae, Chang et al suggested the use of shorter-size screws as compared to screws in non-fractured vertebra; Tian et al suggested using similar-size screws in fractured vertebra as upper and lower vertebra; Sun et al preferred polyaxial intermediate screws; whereas, Guven et al preferred monoaxial screws.^14-17 Kapoen et al²⁸ in their meta-analysis, stated that, despite the fact that 28 studies investigating the application of intermediate screws were conducted, no literature exists on the optimum properties of these intermediate screws. Different types and sizes of pedicular screws were utilized as intermediate screws in these studies; some applied shorter screws in the fractured vertebra compared to screws in the non-fractured vertebra, while others used the same size screws. Also, poly-axial intermediate screws were used by some authors, whereas monoaxial intermediate screws were used by some others. As a result, there is no agreement in the literature on what size and type of intermediate screw is best.

The present retrospective study compared 2 groups of patients in terms of size of the screw placed at the fracture line: in group A, the size of the screw placed at the fracture level was 4.5 mm, ≤35 mm + less than 50% of the vertebral corpus length, whereas the size of the screw placed at the fracture level in group B was 5.5 mm, ≥40 mm + more than 70% of the vertebral corpus length. The groups were similar in terms of age, sex, trauma etiology, fracture level, fracture type (according to the AO classification), neurological status (according to the ASIA disturbance scale), and follow-up. Preoperative assessment also revealed homogeneity in terms of VCA, ABH, and ABH/PBH ratio. Posterior body height was significantly better preserved at the last follow-up in the group that screw placed was more thicker and longer. This is related to the compression of the interfragmentary screw in the pedicle. Kanna et al²⁹ reported in their study that the pedicular screws in the fractured vertebra biomechanically behave as a push point with an anterior vector, providing a lordosing force that corrects the kyphosis as well. The 3-point fixation provides a decrease in the cantilever effects leading to kyphosis. At the stage of reduction, when the appropriately precontoured rod is inserted onto the pedicular screws at the lower end vertebra, it acts as a push point, increasing the forward force and generating a lordosing force on fractured vertebrae. The pedicle screw head that is placed in fractured vertebrae serves as the pivot point for this forward thrust, which causes compression posterior to the screw head and distraction at structures anterior to it³⁰. The PBH was restored significantly after surgery in both groups. Although there is a loss of gained PBH in both groups in follow-up (in group A from 30.65 ± 4.12 mm to 30.47 ± 3.80 mm, in group B from 32.93 ± 3.58 mm to 32.85 ± 2.97 mm), at last control PBH was more significantly preserved in group B than A. Since we used longer, thicker pedicular screws in group B’s fractured vertebrae, they might function more effectively as a push point to increase the forward force on the fractured vertebrae by producing a stronger lordosing effect and a longer anterior vector arm during indirect reduction of the fracture. The pushing power in the middle column which is directly in front of the intact pedicles, which may have been more effective than in the anterior column with the use of thick screws in the fractured vertebra compared to the use of thin screws. As a result, we think that the PPH value in group B is more significant in long-term follow-up due to the stronger pushing force at the time of reduction biomechanically. Except for PBH, the insertion of a long pedicle screw at the fracture level showed no influence on radiological or intraoperative parameters compared to the smaller one.

In their study, Weinstein et al³¹ found that the diameter of the screws had a greater impact on the degree of resistance to screw pullout and flexion-extension loading, whereas the extent of the screws in the vertebrae had a more significant impact on the resistance to lateral bending and axial rotation loading, along with the stress caused by force at the bone-screw interaction. In a non-fractured vertebra, the pullout strength of the pedicle screws was responsible for 60% of the anchoring inside the pedicle and 15%-20% at the cancellous bone in the vertebral body. Chua et al³² stated in their study that pedicle screws should not exceed 85% of the vertebral body length on the lateral view for L1 to reduce the risk of an anterior cortical breach and damage to nearby neurovascular structures while maximizing pedicle screw purchase for fixation durability. In these studies, they only analyzed a single segment. In multisegmented posterior instrumentation, the effect of the change in the size of the pedicular screw placed in the middle part on the resistance to screw pullout and flexion-extension loading, lateral bending, and axial rotation loading has not been investigated in the literature. In addition, the effect of the long and thick pedicular screw placed on the pullout resistance in cases with vertebral fractures may decrease due to the edema (bone bruise) or because it is highly comminuted. All of this could explain why, despite the fact that the fractured vertebra in group B was fixed with a longer and thicker pedicular screw, we obtained similar radiological results in radiological evaluations with group A, except for PBH, which was fixed by placing a thinner and shorter screw on the fractured vertebra in short segment fixation.

We designed our study with the idea that even the shorter and thinner screw on fractured vertebrae in the middle of the construct would add to the system’s stiffness in short-segment posterior instrumentation. According to these findings, using a short and thin pedicular screw in a fractured vertebra in short-segment posterior fixation gives comparable radiological outcomes with a long and thick pedicular screw in follow-up. Short and thin pedicular screws can be preferred on fractured vertebrae during surgery because they provide ease of application during surgery, overcome the difficulties in determining screw length with a spherical tip probe in comminuted fractures that can cause anterior encroachment, and with an acceptable construct stiffness, it can be a viable alternative to anterior augmentation surgical procedures that include transpedicular grafting as well as cementing of the injured vertebra or using a longer and thicker pedicular screw in patients with anterior encroachment.

Some limitations could be noted in this study. It was a retrospective study. A larger patient population is needed for further assessment. Postoperative results of fractures in the thoracolumbar region, rather than a single fracture type, were compared. The idea that inserting a large-diameter screw in fractured vertebrae in highly comminuted fractures where the vertebral body is a bag of bones may cause distraction of the bone fragments and impede healing was not evaluated in this study.³³ Instead of comparing the outcomes of operations performed by a single surgeon, we made a comparison between groups by including patients with thoracolumbar fractures who were operated on by 2 experienced surgeons working in 2 different university hospitals in the same province using a similar method, except for the size of the pedicular screw placed in the fractured vertebra.

In the surgical treatment of thoracolumbar vertebral fractures, although the mobile segment is preserved with short segment fixation, the most important problem is the loss of the reduction obtained in the surgery in long-term follow-ups. With the use of intermediate screws regardless of size in the surgery, the rigidity of the system can be increased, and reduction loss can be prevented in long-term follow-ups. However, there is no consensus in the literature regarding the screw size to be placed in the fractured vertebra. In addition, the effect of the size of the screw placed on the fractured vertebra on the results was not investigated. We have shown in our study that a short and thin pedicular screw in a fractured vertebra in short-segment posterior fixation provides radiological outcomes comparable with a long and thick pedicular screw. The use of a 5.5 mm, ≥40 mm pedicle screw with ≥ 70% vertebral corpus length placed in the fractured vertebra provided better preservation only of the PBH at the final follow-up. No correlation was found between the size of the intermediate screw and the preservation of the correction in the postoperative vertebral heights and VCA during the follow-up.

Funding Statement

The authors declared that this study has received no financial support.

Footnotes

Ethics Committee Approval: This study was approved by Ethics Committee of Ege University (Approval No: 23-3T/44, Date: March 9, 2023).

Informed Consent: Written informed consent was obtained from the patients in the study.

Peer-review: Externally peer-reviewed.

Author Contributions: Concept – A.M.Ö., O.S.; Design – A.M.Ö., O.S., Ö.A.; Supervision – A.M.Ö., O.S., Ö.A.; Resources – A.M.Ö., O.S., S.A., B.K.; Materials – A.M.Ö., O.S., S.A, B.K.; Data Collection and/or Processing – A.M.Ö., O.S., S.A., B.K.; Analysis and/or Interpretation – A.M.Ö., O.S., Ö.A.; Literature Search – A.M.Ö., O.S., S.A., B.K.; Writing – A.M.Ö., O.S., S.A., B.K.; Critical Review – A.M.Ö., O.S., Ö.A.

Declaration of Interests: The authors have no conflict of interest to declare.

References

1. Lyu J, Chen K, Tang Z, Chen Y, Li M, Zhang Q. A comparison of three different surgical procedures in the treatment of type A thoracolumbar fractures: a randomized controlled trial. Int Orthop. 2016;40(6):1233 1238. ( 10.1007/s00264-016-3129-z) [DOI] [PubMed] [Google Scholar]
2. Danisa OA, Shaffrey CI, Jane JA, et al. Surgical approaches for the correction of unstable thoracolumbar burst fractures: a retrospective analysis of treatment outcomes. J Neurosurg. 1995;83(6):977 983. ( 10.3171/jns.1995.83.6.0977) [DOI] [PubMed] [Google Scholar]
3. Wood KB, Bohn D, Mehbod A. Anterior versus posterior treatment of stable thoracolumbar burst fractures without neurologic deficit. A prospective randomized study. J Spinal Disord Tech 2005;83:167 175. [DOI] [PubMed] [Google Scholar]
4. Eno JJ, Chen JL, Mitsunaga MM. Short same-segment fixation of thoracolumbar burst fractures. Hawaii J Med Public Health. 2012;71:19 22. [PMC free article] [PubMed] [Google Scholar]
5. Alanay A, Acaroglu E, Yazici M, Oznur A, Surat A. Shortsegment pedicle instrumentation of thoracolumbar burst fractures: does transpedicular intracorporeal grafting prevent early failure? Spine (Phila Pa 1976). 2001;26(2):213 217. ( 10.1097/00007632-200101150-00017) [DOI] [PubMed] [Google Scholar]
6. Alvine GF, Swain JM, Asher MA, Burton DC. Treatment of thoracolumbar burst fractures with variable screw placement or Isola instrumentation and arthrodesis: case series and literature review. J Spinal Disord Tech. 2004;17(4):251 264. ( 10.1097/01.bsd.0000095827.98982.88) [DOI] [PubMed] [Google Scholar]
7. McLain RF, Sparling E, Benson DR. Early failure of shortsegment pedicle instrumentation for thoracolumbar fractures. A preliminary report. J Bone Joint Surg Am. 1993;75(2):162 167. ( 10.2106/00004623-199302000-00002) [DOI] [PubMed] [Google Scholar]
8. Baaj AA, Reyes PM, Yaqoobi AS, et al. Biomechanical advantage of the index-level pedicle screw in unstable thoracolumbar junction fractures. J Neurosurg Spine. 2011;14(2):192 197. ( 10.3171/2010.10.SPINE10222) [DOI] [PubMed] [Google Scholar]
9. Norton RP, Milne EL, Kaimrajh DN, Eismont FJ, Latta LL, Williams SK. Biomechanical analysis of four- versus six-screw constructs for short-segment pedicle screw and rod instrumentation of unstable thoracolumbar fractures. Spine J. 2014;14(8):1734 1739. ( 10.1016/j.spinee.2014.01.035) [DOI] [PubMed] [Google Scholar]
10. Wang H, Li C, Liu T, Zhao WD, Zhou Y. Biomechanical efficacy of monoaxial or polyaxial pedicle screw and additional screw insertion at the level of fracture, in lumbar burst fracture: an experimental study. Indian J Orthop. 2012;46(4):395 401. ( 10.4103/0019-5413.98827) [DOI] [PMC free article] [PubMed] [Google Scholar]
11. Bolesta MJ, Caron T, Chinthakunta SR, Vazifeh PN, Khalil S. Pedicle screw instrumentation of thoracolumbar burst fractures: biomechanical evaluation of screw configuration with pedicle screws at the level of the fracture. Int J Spine Surg. 2012;6:200 205. ( 10.1016/j.ijsp.2012.09.002) [DOI] [PMC free article] [PubMed] [Google Scholar]
12. Mahar A, Kim C, Wedemeyer M, et al. Short-segment fixation of lumbar burst fractures using pedicle fixation at the level of the fracture. Spine (Phila Pa 1976). 2007;32(14):1503 1507. ( 10.1097/BRS.0b013e318067dd24) [DOI] [PubMed] [Google Scholar]
13. Dobran M, Nasi D, Brunozzi D, et al. Treatment of unstable thoracolumbar junction fractures: short-segment pedicle fixation with inclusion of the fracture level versus long-segment instrumentation. Acta Neurochir. 2016;158(10):1883 1889. ( 10.1007/s00701-016-2907-0) [DOI] [PubMed] [Google Scholar]
14. Guven O, Kocaoglu B, Bezer M, Aydin N, Nalbantoglu U. The use of screw at the fracture level in the treatment of thoracolumbar burst fractures. J Spinal Disord Tech. 2009;22(6):417 421. ( 10.1097/BSD.0b013e3181870385) [DOI] [PubMed] [Google Scholar]
15. Chang R, Wang FA, Hao W. Treatment of a thoracolumbar burst fracture with short segment pedicular screw fixation through the fractured vertebra. Orthop J China. 2014;22:683 686. [Google Scholar]
16. Tian JW, Wang L, Xia T, Liu CY, Zhao QH, Dong SH. Posterior short-segmental fixation combined with intermediate screws vs conventional intersegmental fixation for monosegmental thoracolumbar fractures. Orthopedics. 2011;34(8):e389 e396. ( 10.3928/01477447-20110627-08) [DOI] [PubMed] [Google Scholar]
17. Sun C, Guan G, Liu X, Zhang H, Wang B. Comparison of short-segment pedicle fixation with versus without inclusion of the fracture level in the treatment of mild thoracolumbar burst fractures. Int J Surg. 2016;36(A):352 357. ( 10.1016/j.ijsu.2016.11.086) [DOI] [PubMed] [Google Scholar]
18. Vaccaro AR, Oner C, Kepler CK, et al. AOSpine thoracolumbar spine injury classification system: fracture description, neurological status, and key modifiers. Spine (Phila Pa 1976. 2013;38(23):2028 2037. ( 10.1097/BRS.0b013e3182a8a381) [DOI] [PubMed] [Google Scholar]
19. Keynan O, Fisher CG, Vaccaro A, et al. Radiographic measurement parameters in thoracolumbar fractures: a systematic review and consensus statement of the spine trauma study group. Spine (Phila Pa 1976). 2006;31(5):E156 E165. ( 10.1097/01.brs.0000201261.94907.0d) [DOI] [PubMed] [Google Scholar]
20. Altay M, Ozkurt B, Aktekin CN, Ozturk AM, Dogan O, Tabak AY. Treatment of unstable thoracolumbar junction burst fractures with short- or long-segment posterior fixation in Magerl type A fractures. Eur Spine J. 2007;16(8):1145 1155. ( 10.1007/s00586-007-0310-5) [DOI] [PMC free article] [PubMed] [Google Scholar]
21. Cheng LM, Wang JJ, Zeng ZL, et al. Pedicle screw fixation for traumatic fractures of the thoracic and lumbar spine. Cochrane Database Syst Rev. 2013;5(5):CD009073. ( 10.1002/14651858.CD009073.pub2) [DOI] [PMC free article] [PubMed] [Google Scholar]
22. Farrokhi MR, Razmkon A, Maghami Z, Nikoo Z. Inclusion of the fracture level in short segment fixation of thoracolumbar fractures. Eur Spine J. 2010;19(10):1651 1656. ( 10.1007/s00586-010-1449-z) [DOI] [PMC free article] [PubMed] [Google Scholar]
23. Hu R, Mustard CA, Burns C. Epidemiology of incident spinal fracture in a complete population. Spine. 1996;21(4):492 499. ( 10.1097/00007632-199602150-00016) [DOI] [PubMed] [Google Scholar]
24. Payer M. Unstable burst fractures of the thoraco-lumbar junction: treatment by posterior bisegmental correction/fixation and staged anterior corpectomy and titanium cage implantation. Acta Neurochir (Wien). 2006;148(3):299 306; discussion 306. ( 10.1007/s00701-005-0681-5) [DOI] [PubMed] [Google Scholar]
25. Ökten Aİ, Gezercan Y, Özsoy KM, et al. Results of treatment of unstable thoracolumbar burst fractures using pedicle instrumentation with and without fracture-level screws. Acta Neurochir (Wien). 2015;157(5):831 836. ( 10.1007/s00701-015-2383-y) [DOI] [PubMed] [Google Scholar]
26. Dick JC, Jones MP, Zdeblick TA, Kunz DN, Horton WC. A biomechanical comparison evaluating the use of intermediate screws and cross-linkage in lumbar pedicle fixation. J Spinal Disord. 1994;7(5):402 407. ( 10.1097/00002517-199410000-00006) [DOI] [PubMed] [Google Scholar]
27. El Behairy HF, Abdelaziz MA, Saleh AK, et al. Short-segment fixation of thoracolumbar fractures with incorporated screws at the level of fracture. Orthop Surg. 2020;12:170 176. [DOI] [PMC free article] [PubMed] [Google Scholar]
28. Kapoen C, Liu Y, Bloemers FW, Deunk J. Pedicle screw fixation of thoracolumbar fractures: conventional short segment versus short segment with intermediate screws at the fracture level-a systematic review and meta-analysis. Eur Spine J. 2020;29(10):2491 2504. ( 10.1007/s00586-020-06479-4) [DOI] [PubMed] [Google Scholar]
29. Kanna RM, Shetty AP, Rajasekaran S. Posterior fixation including the fractured vertebra for severe unstable thoracolumbar fractures. Spine J. 2015;15(2):256 264. ( 10.1016/j.spinee.2014.09.004) [DOI] [PubMed] [Google Scholar]
30. Jindal R, Jasani V, Sandal D, Garg SK. Current status of short segment fixation in thoracolumbar spine injuries. J Clin Orthop Trauma. 2020;11(5):770 777. ( 10.1016/j.jcot.2020.06.008) [DOI] [PMC free article] [PubMed] [Google Scholar]
31. Weinstein JN, Rydevik BL, Rauschning W. Anatomic and technical considerations of pedicle screw fixation. Clin Orthop Relat Res. 1992;284(284):34 46. [PubMed] [Google Scholar]
32. Chua MJ, Siddiqui S, Yu CS, Nolan CP, Oh JY. The optimal screw length of lumbar pedicle screws during minimally invasive surgery fixation: A computed tomography-guided evaluation of 771 screws. Asian Spine J. 2019;13(6):936 941. ( 10.31616/asj.2018.0276) [DOI] [PMC free article] [PubMed] [Google Scholar]
33. Kose KC, Inanmaz ME, Isik C, Basar H, Caliskan I, Bal E. Short segment pedicle screw instrumentation with an index level screw and cantilevered hyperlordotic reduction in the treatment of type-A fractures of the thoracolumbar spine. Bone Joint J. 2014;96-B(v):541 547. ( 10.1302/0301-620X.96B4.33249) [DOI] [PubMed] [Google Scholar]

[b1-aott-58-1-20] 1. Lyu J, Chen K, Tang Z, Chen Y, Li M, Zhang Q. A comparison of three different surgical procedures in the treatment of type A thoracolumbar fractures: a randomized controlled trial. Int Orthop. 2016;40(6):1233 1238. ( 10.1007/s00264-016-3129-z) [DOI] [PubMed] [Google Scholar]

[b2-aott-58-1-20] 2. Danisa OA, Shaffrey CI, Jane JA, et al. Surgical approaches for the correction of unstable thoracolumbar burst fractures: a retrospective analysis of treatment outcomes. J Neurosurg. 1995;83(6):977 983. ( 10.3171/jns.1995.83.6.0977) [DOI] [PubMed] [Google Scholar]

[b3-aott-58-1-20] 3. Wood KB, Bohn D, Mehbod A. Anterior versus posterior treatment of stable thoracolumbar burst fractures without neurologic deficit. A prospective randomized study. J Spinal Disord Tech 2005;83:167 175. [DOI] [PubMed] [Google Scholar]

[b4-aott-58-1-20] 4. Eno JJ, Chen JL, Mitsunaga MM. Short same-segment fixation of thoracolumbar burst fractures. Hawaii J Med Public Health. 2012;71:19 22. [PMC free article] [PubMed] [Google Scholar]

[b5-aott-58-1-20] 5. Alanay A, Acaroglu E, Yazici M, Oznur A, Surat A. Shortsegment pedicle instrumentation of thoracolumbar burst fractures: does transpedicular intracorporeal grafting prevent early failure? Spine (Phila Pa 1976). 2001;26(2):213 217. ( 10.1097/00007632-200101150-00017) [DOI] [PubMed] [Google Scholar]

[b6-aott-58-1-20] 6. Alvine GF, Swain JM, Asher MA, Burton DC. Treatment of thoracolumbar burst fractures with variable screw placement or Isola instrumentation and arthrodesis: case series and literature review. J Spinal Disord Tech. 2004;17(4):251 264. ( 10.1097/01.bsd.0000095827.98982.88) [DOI] [PubMed] [Google Scholar]

[b7-aott-58-1-20] 7. McLain RF, Sparling E, Benson DR. Early failure of shortsegment pedicle instrumentation for thoracolumbar fractures. A preliminary report. J Bone Joint Surg Am. 1993;75(2):162 167. ( 10.2106/00004623-199302000-00002) [DOI] [PubMed] [Google Scholar]

[b8-aott-58-1-20] 8. Baaj AA, Reyes PM, Yaqoobi AS, et al. Biomechanical advantage of the index-level pedicle screw in unstable thoracolumbar junction fractures. J Neurosurg Spine. 2011;14(2):192 197. ( 10.3171/2010.10.SPINE10222) [DOI] [PubMed] [Google Scholar]

[b9-aott-58-1-20] 9. Norton RP, Milne EL, Kaimrajh DN, Eismont FJ, Latta LL, Williams SK. Biomechanical analysis of four- versus six-screw constructs for short-segment pedicle screw and rod instrumentation of unstable thoracolumbar fractures. Spine J. 2014;14(8):1734 1739. ( 10.1016/j.spinee.2014.01.035) [DOI] [PubMed] [Google Scholar]

[b10-aott-58-1-20] 10. Wang H, Li C, Liu T, Zhao WD, Zhou Y. Biomechanical efficacy of monoaxial or polyaxial pedicle screw and additional screw insertion at the level of fracture, in lumbar burst fracture: an experimental study. Indian J Orthop. 2012;46(4):395 401. ( 10.4103/0019-5413.98827) [DOI] [PMC free article] [PubMed] [Google Scholar]

[b11-aott-58-1-20] 11. Bolesta MJ, Caron T, Chinthakunta SR, Vazifeh PN, Khalil S. Pedicle screw instrumentation of thoracolumbar burst fractures: biomechanical evaluation of screw configuration with pedicle screws at the level of the fracture. Int J Spine Surg. 2012;6:200 205. ( 10.1016/j.ijsp.2012.09.002) [DOI] [PMC free article] [PubMed] [Google Scholar]

[b12-aott-58-1-20] 12. Mahar A, Kim C, Wedemeyer M, et al. Short-segment fixation of lumbar burst fractures using pedicle fixation at the level of the fracture. Spine (Phila Pa 1976). 2007;32(14):1503 1507. ( 10.1097/BRS.0b013e318067dd24) [DOI] [PubMed] [Google Scholar]

[b13-aott-58-1-20] 13. Dobran M, Nasi D, Brunozzi D, et al. Treatment of unstable thoracolumbar junction fractures: short-segment pedicle fixation with inclusion of the fracture level versus long-segment instrumentation. Acta Neurochir. 2016;158(10):1883 1889. ( 10.1007/s00701-016-2907-0) [DOI] [PubMed] [Google Scholar]

[b14-aott-58-1-20] 14. Guven O, Kocaoglu B, Bezer M, Aydin N, Nalbantoglu U. The use of screw at the fracture level in the treatment of thoracolumbar burst fractures. J Spinal Disord Tech. 2009;22(6):417 421. ( 10.1097/BSD.0b013e3181870385) [DOI] [PubMed] [Google Scholar]

[b15-aott-58-1-20] 15. Chang R, Wang FA, Hao W. Treatment of a thoracolumbar burst fracture with short segment pedicular screw fixation through the fractured vertebra. Orthop J China. 2014;22:683 686. [Google Scholar]

[b16-aott-58-1-20] 16. Tian JW, Wang L, Xia T, Liu CY, Zhao QH, Dong SH. Posterior short-segmental fixation combined with intermediate screws vs conventional intersegmental fixation for monosegmental thoracolumbar fractures. Orthopedics. 2011;34(8):e389 e396. ( 10.3928/01477447-20110627-08) [DOI] [PubMed] [Google Scholar]

[b17-aott-58-1-20] 17. Sun C, Guan G, Liu X, Zhang H, Wang B. Comparison of short-segment pedicle fixation with versus without inclusion of the fracture level in the treatment of mild thoracolumbar burst fractures. Int J Surg. 2016;36(A):352 357. ( 10.1016/j.ijsu.2016.11.086) [DOI] [PubMed] [Google Scholar]

[b18-aott-58-1-20] 18. Vaccaro AR, Oner C, Kepler CK, et al. AOSpine thoracolumbar spine injury classification system: fracture description, neurological status, and key modifiers. Spine (Phila Pa 1976. 2013;38(23):2028 2037. ( 10.1097/BRS.0b013e3182a8a381) [DOI] [PubMed] [Google Scholar]

[b19-aott-58-1-20] 19. Keynan O, Fisher CG, Vaccaro A, et al. Radiographic measurement parameters in thoracolumbar fractures: a systematic review and consensus statement of the spine trauma study group. Spine (Phila Pa 1976). 2006;31(5):E156 E165. ( 10.1097/01.brs.0000201261.94907.0d) [DOI] [PubMed] [Google Scholar]

[b20-aott-58-1-20] 20. Altay M, Ozkurt B, Aktekin CN, Ozturk AM, Dogan O, Tabak AY. Treatment of unstable thoracolumbar junction burst fractures with short- or long-segment posterior fixation in Magerl type A fractures. Eur Spine J. 2007;16(8):1145 1155. ( 10.1007/s00586-007-0310-5) [DOI] [PMC free article] [PubMed] [Google Scholar]

[b21-aott-58-1-20] 21. Cheng LM, Wang JJ, Zeng ZL, et al. Pedicle screw fixation for traumatic fractures of the thoracic and lumbar spine. Cochrane Database Syst Rev. 2013;5(5):CD009073. ( 10.1002/14651858.CD009073.pub2) [DOI] [PMC free article] [PubMed] [Google Scholar]

[b22-aott-58-1-20] 22. Farrokhi MR, Razmkon A, Maghami Z, Nikoo Z. Inclusion of the fracture level in short segment fixation of thoracolumbar fractures. Eur Spine J. 2010;19(10):1651 1656. ( 10.1007/s00586-010-1449-z) [DOI] [PMC free article] [PubMed] [Google Scholar]

[b23-aott-58-1-20] 23. Hu R, Mustard CA, Burns C. Epidemiology of incident spinal fracture in a complete population. Spine. 1996;21(4):492 499. ( 10.1097/00007632-199602150-00016) [DOI] [PubMed] [Google Scholar]

[b24-aott-58-1-20] 24. Payer M. Unstable burst fractures of the thoraco-lumbar junction: treatment by posterior bisegmental correction/fixation and staged anterior corpectomy and titanium cage implantation. Acta Neurochir (Wien). 2006;148(3):299 306; discussion 306. ( 10.1007/s00701-005-0681-5) [DOI] [PubMed] [Google Scholar]

[b25-aott-58-1-20] 25. Ökten Aİ, Gezercan Y, Özsoy KM, et al. Results of treatment of unstable thoracolumbar burst fractures using pedicle instrumentation with and without fracture-level screws. Acta Neurochir (Wien). 2015;157(5):831 836. ( 10.1007/s00701-015-2383-y) [DOI] [PubMed] [Google Scholar]

[b26-aott-58-1-20] 26. Dick JC, Jones MP, Zdeblick TA, Kunz DN, Horton WC. A biomechanical comparison evaluating the use of intermediate screws and cross-linkage in lumbar pedicle fixation. J Spinal Disord. 1994;7(5):402 407. ( 10.1097/00002517-199410000-00006) [DOI] [PubMed] [Google Scholar]

[b27-aott-58-1-20] 27. El Behairy HF, Abdelaziz MA, Saleh AK, et al. Short-segment fixation of thoracolumbar fractures with incorporated screws at the level of fracture. Orthop Surg. 2020;12:170 176. [DOI] [PMC free article] [PubMed] [Google Scholar]

[b28-aott-58-1-20] 28. Kapoen C, Liu Y, Bloemers FW, Deunk J. Pedicle screw fixation of thoracolumbar fractures: conventional short segment versus short segment with intermediate screws at the fracture level-a systematic review and meta-analysis. Eur Spine J. 2020;29(10):2491 2504. ( 10.1007/s00586-020-06479-4) [DOI] [PubMed] [Google Scholar]

[b29-aott-58-1-20] 29. Kanna RM, Shetty AP, Rajasekaran S. Posterior fixation including the fractured vertebra for severe unstable thoracolumbar fractures. Spine J. 2015;15(2):256 264. ( 10.1016/j.spinee.2014.09.004) [DOI] [PubMed] [Google Scholar]

[b30-aott-58-1-20] 30. Jindal R, Jasani V, Sandal D, Garg SK. Current status of short segment fixation in thoracolumbar spine injuries. J Clin Orthop Trauma. 2020;11(5):770 777. ( 10.1016/j.jcot.2020.06.008) [DOI] [PMC free article] [PubMed] [Google Scholar]

[b31-aott-58-1-20] 31. Weinstein JN, Rydevik BL, Rauschning W. Anatomic and technical considerations of pedicle screw fixation. Clin Orthop Relat Res. 1992;284(284):34 46. [PubMed] [Google Scholar]

[b32-aott-58-1-20] 32. Chua MJ, Siddiqui S, Yu CS, Nolan CP, Oh JY. The optimal screw length of lumbar pedicle screws during minimally invasive surgery fixation: A computed tomography-guided evaluation of 771 screws. Asian Spine J. 2019;13(6):936 941. ( 10.31616/asj.2018.0276) [DOI] [PMC free article] [PubMed] [Google Scholar]

[b33-aott-58-1-20] 33. Kose KC, Inanmaz ME, Isik C, Basar H, Caliskan I, Bal E. Short segment pedicle screw instrumentation with an index level screw and cantilevered hyperlordotic reduction in the treatment of type-A fractures of the thoracolumbar spine. Bone Joint J. 2014;96-B(v):541 547. ( 10.1302/0301-620X.96B4.33249) [DOI] [PubMed] [Google Scholar]

PERMALINK

The effect of the size of pedicle screw on the long-term radiological and clinical results of short-segment posterior instrumentation in the management of thoracolumbar vertebral fractures

Anıl Murat Öztürk

Onur Süer

Selahaddin Aydemir

Bünyamin Kılıçlı

Ömer Akçalı