Advantages of Posterior Indirect Decompression Surgery in Thoracolumbar Burst Fractures with Neurologic Symptoms

Article information

Nerve. 2023;9(1):18-26
Publication date (electronic) : 2023 April 20
doi : https://doi.org/10.21129/nerve.2022.00227
1Department of Neurosurgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
2Department of Neurosurgery, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Republic of Korea
Corresponding author: Jung Jae Lee Department of Neurosurgery, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 271, Cheonbo-ro, Uijeongbu 11765, Republic of Korea Tel: +82-33-610-3260 Fax: +82-33-610-3111 E-mail: whitetiger0083@gmail.com
Received 2022 November 4; Revised 2023 January 4; Accepted 2023 February 3.

Abstract

Objective

Approximately 90% of spinal fractures occur at the thoracolumbar (T-L) junction and may be accompanied by neurological symptoms, in which decompression and post-fixation are generally performed. However, decompression surgery can aggravate patients’ symptoms due to adverse incidents, such as developing postoperative hematomas or iatrogenic spinal cord injury. This study compared the surgical and radiographic outcomes of patients with T-L junction burst fractures and neurological deficits who underwent direct or indirect decompression.

Methods

We retrospectively reviewed all patients who had undergone posterior surgical treatment for T-L junction burst fractures with neurologic deficits. Patients were classified according to the procedure: indirect decompression (group 1) or spinal decompression through laminectomy and facetectomy (group 2). Clinical results and radiologic findings were compared between the two groups for 2 years.

Results

Among 57 patients who met the inclusion criteria, 29 were categorized into group 1, and 28 were categorized into group 2. Group 1 had a statistically significantly lower Oswestry Disability Index score than group 2 at the final follow-up visit (p=0.03). In group 1, both the T-L junction angle and wedge angle of the injured vertebrae improved significantly, both immediately after surgery (p=0.02 and p=0.01, respectively) and at the final follow-up visit (p=0.01 and p=0.01, respectively). In group 2, the difference between the pelvic incidence and lumbar lordosis was significantly greater than in group 1 at the final follow-up visit (p=0.02).

Conclusion

This study confirmed that symptoms could be sufficiently improved with indirect decompression, which should be kept in mind for cases where it is difficult to perform direct decompression,

INTRODUCTION

Approximately 90% of spinal fractures occur at the thoracolumbar (T-L) junction7,15,28), including burst fractures and T-L vertebral collapse. T-L burst fracture is defined according to the presence of fractures or comminutions in both the anterior and middle columns, with the bony fragments retracted into the spinal canal5). A T-L burst fracture with a fractured and reverse-oscillating posterior vertebral wall can cause neurological deficits when bone fragments persist in the spinal canal during or after trauma19,27). Without appropriate treatment, these complications substantially affect physical health, occupational daily activities, and overall quality of life18).

Surgery is primarily indicated to relieve spinal cord compression and restore neural function4,20,26). In patients diagnosed with fractures of the vertebral bodies and posterior elements with some degree of misalignment of the spine or those with T-L junction fractures presenting with spinal canal injuries and neurological symptoms, timely decompression and internal immobilization should be performed to restore vertebral body height and vertebral canal volume. The goal is to restore spinal stability as soon as possible in accordance with current medical guidelines14,21).

Various surgical options are available for the management of T-L burst fractures, including posterior fixation and decompression, as well as direct anterior decompression through vertebral resection6,10,12,22). Posterior decompression and fixation are the most commonly implemented methods. However, decompression can aggravate neurologic symptoms, with postoperative hematomas or spinal cord injury commonly presenting in patients who have difficulty coagulating13). In contrast, indirect decompression can decompress nerve tissue without excising the compressed tissue. This method is primarily performed through distraction between the two vertebrae, which opens the neural foramen and increases the epidural space. Therefore, this technique allows for nerve tissue decompression without excision of the compression fragment. Distraction and ligamentotaxis indirectly lead to reduced fracture fragments, resulting in restoration of corpus height, kyphosis correction, and canal widening16,30).

We ought to establish the surgical outcomes of indirect decompression in patients with T-L junction burst fractures presenting with neurological deficits. Toward this goal, we retrospectively evaluated the surgical outcomes of patients who underwent indirect decompression surgery and compared these outcomes to patients who underwent posterior fixation after laminectomy.

MATERIALS AND METHODS

1. Demographic Evaluation

The institutional review board at the participating medical center approved this study. Patients who underwent surgery at our tertiary medical center between August 2013 and January 2020 for traumatic T-L junction fractures with neurological deficits were retrospectively reviewed.

We included patients who (1) underwent posterior fusion surgery for a single-level burst fracture of the T-L junction from the T11 to L2 level with traumatic spinal cord injury; (2) had no prior history of spinal surgery; (3) had received surgical treatment within 48 hr after trauma; (4) only had radiating pain without motor function impairment; and (5) had a minimum follow-up of 24 months.

We excluded patients who (1) had a follow-up period shorter than 24 months; (2) presented with multi-level spinal fractures; (3) had a history of previous posterior spinal surgery; (4) had severe comorbidities (e.g., cancer metastasis, infectious diseases) that may adversely affect bone healing; and (5) experienced neurological defects such as motor weakness or cauda equina syndrome. Indirect decompression surgery was performed in patients for whom direct decompression surgery could not be performed due to age, underlying disease, and medications. Direct decompression and post-fixation surgery were performed in all other patients.

Demographic data were collected through questionnaires administered to all patients, including data on age, sex, underlying disease, injured vertebra level, smoking history, body mass index (BMI), surgical details, a range of follow-up information, data abstracted from electronic medical records, estimated blood loss during surgery, and operative times. We did not obtain consent for participation from the enrolled patients owing to the retrospective nature of the study. Thus, the normal requirement for informed consent was waived during the ethics review process.

2. Pain and Quality of Life Evaluation

Patient-reported questionnaires were administered before surgery during outpatient clinic visits. Pain levels were quantified using a visual analog scale (VAS) with respect to back and leg pain both pre- and post- operatively (immediate, 12-month, and 24-month follow-up). The effects on disability and quality of life were measured using the Oswestry Disability Index (ODI) questionnaire at the same time points. A satisfaction questionnaire evaluating the received treatment was also administered. In cases where it was difficult for patients to complete a questionnaire, results were verified by a telephonic interview conducted with a member of the study staff.

3. Operative Technique

All patients were placed in a prone position with a Wilson frame adjoining the thoracic and iliac spines, thus straining the anterior columns of the spine to reset the spinal curvature. A midline skin incision was made, and the paravertebral muscles were separated bilaterally from the spinous process to expose the lamina and facet joint. The pedicle of the fractured vertebral body was evaluated using C-arm fluoroscopy. Segmental screws were inserted into one or two vertebrae above and one vertebra below the level of the fracture via the freehand technique. Six to eight pedicle screws were inserted into the pedicle. Polyaxial pedicle screws were inserted into the upper and lower normal vertebrae, and axial pedicle screws were inserted into the fractured vertebrae. A screw 5 to 10 mm shorter than the vertebra was inserted into the pedicle screw of the upper and lower normal vertebrae. The connecting rod was then inserted and fixed with a cap.

In group 1 (the indirect decompression group), indirect decompression can be achieved through distraction by identifying areas with burst fractures, dura compression, and segmental kyphosis with a C-arm and performing distraction between the posterior segmental instruments above and below the area (Fig. 1).

Fig. 1.

A T12-L1 rod was distracted for the purpose of L1 indirect vertebral body decompression in patients with L1 burst fractures.

In group 2 (the direct decompression group), we performed posterior decompression, including laminectomy and facetectomy, to widen the spinal canal when cord compression was observed following a fracture.

4. Radiographic Evaluation

We performed magnetic resonance imaging (MRI) and multi-slice computed tomography imaging of the T-L spine in all patients. Using sagittal MRI images, we calculated dural sac compression due to epidural hematoma or bone fragments. The dural compression ratio presents the ratio of compressed to supposedly normal dura at the level of the injury. This ratio was calculated using the following equation: (1 − C/[(A + B)/2]) × 100)11) (Fig. 2).

Fig. 2.

Dural compression ratios were calculated using the following equation: (1−C/[A+B]/2)×100. We evaluated (A) the dura mater at the cephalad non-compressed level, (B) the dura mater at the caudal non-compressed level, and (C) the dura mater at the injury level.

We measured the angle of the T-L junction, thus evaluating kyphosis according to the Cobb method9). The Cobb angle was measured from the upper-end plate of T10 and the lower-end plate of L2. We also measured spinal parameters. These parameters included thoracic kyphosis (TK; T5-12), lumbar lordosis (LL; L1-S1), and pelvic incidence (PI)-LL mismatch. In addition, we recorded the wedge angle (WA) of the injured vertebral body. All radiological parameters were checked preoperatively, immediately postoperatively, and at the final (24-month) follow-up visit.

5. Statistical Analyses

Continuous variables were described as the mean ± standard deviation, and categorical variables were expressed as frequencies or percentages. Additionally, Student’s t-test, χ2, and Fisher’s exact tests were used to determine statistically significant differences in radiological and clinical outcomes between the two groups. All statistical analyses were performed using SPSS Statistics for Windows, Version 17.0 (IBM Corp., Armonk, NY, USA). A p-value of less than 0.05 was considered statistically significant.

RESULTS

1. Demographic Analysis

A total of 57 patients were enrolled in this study. Among these patients, 29 were categorized into group 1, and 28 were categorized into group 2. Among those in group 1, 19 were taking anticoagulants, 7 were ≥80 years old, and 3 had a hematologic disease. Serious complications, such as nerve root and spinal cord injuries, screw malposition, broken screws, and rods, hematomas pressing on the spinal cord, or wound infections, were not observed in enrolled patients. Age, sex, underlying disease, fractured vertebra level, bone marrow density, BMI, and smoking history distributions did not significantly differ between the two groups (Table 1).

Comparative descriptive statistics with respect to medical and demographic variables

2. Comparative Analysis of Surgical Information

Intraoperative bleeding volume was lower in group 1 vs. group 2; however, this difference was not statistically significant. In addition, there were no significant differences in the surgical level at which fixation was performed or the preoperative dura compression ratio. However, the indirect decompression group had a significantly shorter mean operative time than the direct decompression group (31 min, p=0.03; Table 2).

Comparison of surgical time, intraoperative bleeding, and surgical factors between the 2 groups

3. Clinical Outcome

We found that the VAS and ODI scores before surgery as well as immediately after surgery were lower in group 1 than in group 2, with no significant differences between the two. However, at the final follow-up, patients in group 1 had significantly lower ODI scores compared with those in group 2 (p=0.03; Table 3).

Clinical outcomes during the study follow-up period of both groups

4. Comparative Radiological Results

No significant between-group differences were observed for any of the pre-surgical radiologic parameters. Regarding the WA of the injured vertebral body, it was confirmed that the kyphotic angle was significantly smaller in group 1 compared to that in group 2 immediately after surgery (p=0.01) and at the last follow-up (p=0.01). In the angle of T-L junction, a statistically significantly smaller kyphotic angle was observed in group 1 immediately after surgery (p = 0.02), which was also confirmed at the final follow-up (p=0.01) (Fig. 3, Table 4). No significant differences in TK or LL were observed between the two groups. Group 2 had a larger PI-LL discrepancy than Group 1 at the final follow-up visit (p=0.02; Table 4).

Fig. 3.

Comparison of the vertebral body and thoracolumbar junction before and after surgery (24 months). Comparison of angular changes between the direct decompression surgery group using lateral X-ray (A, preoperative; B, 24 months postoperative) and the indirect decompression surgery group (C, preoperative; D, 24 months postoperative).

Comparative radiologic parameters between the surgical groups

DISCUSSION

This is the first study to compare the clinical and radiological features of patients with T-L junction burst fractures presenting with neurological symptoms who underwent indirect decompression surgery with those of patients who underwent direct decompression surgery.

The T-L junction segment is located at the physiological stress concentration points of the spinal cord15). Burst fractures typically lead to various symptoms caused by spinal cord compression due to the presence of bone fragments and epidural hematomas. Decompression and post-fixation are normally performed in the presence of neurological symptoms. However, direct decompression of the spinal cord area can aggravate hematomas or spinal cord injuries and cause dural tearing29). Moreover, older age, anticoagulant use, and many risk factors during surgery have been identified as causes of postoperative spinal epidural hematoma3,8,13,25). Therefore, we performed indirect decompression surgery for these at-risk patients.

Many studies have been conducted on partial lordosis and total spinal alignment correction using indirect decompression with a posterior approach1,2,17). In our study, the indirect decompression group showed lower WA and T-L junction angles. However, no significant differences were observed with respect to TK and LL. Future studies performing surgeries involving larger numbers of patients and more levels of the spine are needed.

In terms of PI-LL mismatch, we found a significant difference in the direct decompression group immediately after surgery. Schwab et al.23) viewed PI-LL mismatch as a key parameter related to postoperative patient disability and health-related quality of life. Seo et al.24) reported that a T-L junction Cobb angle larger than 10.5° immediately after surgery was associated with unfavorable radiological outcomes, which, in turn, were associated with poor clinical outcomes. In the current study, we confirmed that ODI scores were worse in the direct vs. indirect decompression group. The T-L kyphotic angle in the direct decompression group was 10.5° or higher. Consequently, we confirmed that clinical radiological results improved in the indirect vs. direct decompression group. Furthermore, there was less improvement in kyphotic angle in the direct vs. indirect decompression group, resulting in a larger T-L junction kyphosis and whole spine malalignment, which consequently adversely affected ODI score improvements.

In addition to the substantial strengths of this study, we acknowledge several limitations. First, we enrolled a small sample size selected from a single medical center. Moreover, comparative study groups were lacking in the current study design. In particular, comparisons were not made according to various fracture shapes, e.g., pedicle fractures. Further comparative studies involving larger case series and fractures of various shapes are needed to confirm our findings in patients with T-L junction vertebral fractures. Second, the follow-up period was relatively short. Additional studies with longer follow-up periods are required to validate the neurological changes observed in this study.

CONCLUSION

In this study, the clinical and radiological results of direct and indirect decompression were compared. We sought to confirm the usefulness of indirect decompression in patients with T-L junction tear fractures and neurological symptoms when direct decompression was difficult. Indirect decompression was associated with better clinical outcomes and improved radiographic alignment compared to direct decompression. Further studies with more patients and longer duration are needed. However, our findings will serve as a reference to guide future research and provide direct information for medical guidelines and clinical decision-making.

Notes

No potential conflict of interest relevant to this article was reported.

References

1. Abumi K, Shono Y, Taneichi H, Ito M, Kaneda K. Correction of cervical kyphosis using pedicle screw fixation systems. Spine (Phila Pa 1976) 24:2389–2396. 1999;
2. Ando K, Imagama S, Ito Z, Kobayashi K, Ukai J, Muramoto A, et al. Ponte Osteotomy During Dekyphosis for Indirect Posterior Decompression With Ossification of the Posterior Longitudinal Ligament of the Thoracic Spine. Clin Spine Surg 30:E358–E362. 2017;
3. Awad JN, Kebaish KM, Donigan J, Cohen DB, Kostuik JP. Analysis of the risk factors for the development of post-operative spinal epidural haematoma. J Bone Joint Surg Br 87:1248–1252. 2005;
4. Chen SL, Huang YH, Wei TY, Huang KM, Ho SH, Bih LI. Motor and bladder dysfunctions in patients with vertebral fractures at the thoracolumbar junction. Eur Spine J 21:844–849. 2012;
5. Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine (Phila Pa 1976) 8:817–831. 1983;
6. Dobran M, Nasi D, Brunozzi D, di Somma L, Gladi M, Iacoangeli M, et al. Treatment of unstable thoracolumbar junction fractures: short-segment pedicle fixation with inclusion of the fracture level versus long-segment instrumentation. Acta Neurochir (Wien) 158:1883–1889. 2016;
7. Esses SI, Botsford DJ, Kostuik JP. Evaluation of surgical treatment for burst fractures. Spine (Phila Pa 1976) 15:667–673. 1990;
8. Fraser S, Roberts L, Murphy E. Cauda equina syndrome: a literature review of its definition and clinical presentation. Arch Phys Med Rehabil 90:1964–1968. 2009;
9. Harrison DE, Cailliet R, Harrison DD, Janik TJ, Holland B. Reliability of centroid, Cobb, and Harrison posterior tangent methods: which to choose for analysis of thoracic kyphosis. Spine (Phila Pa 1976) 26:E227–E234. 2001;
10. Kaneda K, Taneichi H, Abumi K, Hashimoto T, Satoh S, Fujiya M. Anterior decompression and stabilization with the Kaneda device for thoracolumbar burst fractures associated with neurological deficits. J Bone Joint Surg Am 79:69–83. 1997;
11. Kawano O, Ueta T, Shiba K, Iwamoto Y. Outcome of decompression surgery for cervical spinal cord injury without bone and disc injury in patients with spinal cord compression: a multicenter prospective study. Spinal Cord 48:548–553. 2010;
12. Keys HM, Bundy BN, Stehman FB, Muderspach LI, Chafe WE, Suggs CL, et al. Cisplatin, radiation, and adjuvant hysterectomy compared with radiation and adjuvant hysterectomy for bulky stage IB cervical carcinoma. N Engl J Med 340:1154–1161. 1999;
13. Kou J, Fischgrund J, Biddinger A, Herkowitz H. Risk factors for spinal epidural hematoma after spinal surgery. Spine (Phila Pa 1976) 27:1670–1673. 2002;
14. Leferink VJ, Nijboer JM, Zimmerman KW, Veldhuis EF, ten Vergert EM, ten Duis HJ. Burst fractures of the thoracolumbar spine: changes of the spinal canal during operative treatment and follow-up. Eur Spine J 12:255–260. 2003;
15. Lin B, Chen ZW, Guo ZM, Liu H, Yi ZK. Anterior Approach Versus Posterior Approach With Subtotal Corpectomy, Decompression, and Reconstruction of Spine in the Treatment of Thoracolumbar Burst Fractures: A Prospective Randomized Controlled Study. J Spinal Disord Tech 25:309–317. 2012;
16. Malham GM, Parker RM, Goss B, Blecher CM, Ballok ZE. Indirect foraminal decompression is independent of metabolically active facet arthropathy in extreme lateral interbody fusion. Spine (Phila Pa 1976) 39:E1303–E1310. 2014;
17. Matsuyama Y, Sakai Y, Katayama Y, Imagama S, Ito Z, Wakao N, et al. Indirect posterior decompression with corrective fusion for ossification of the posterior longitudinal ligament of the thoracic spine: is it possible to predict the surgical results? Eur Spine J 18:943–948. 2009;
18. McLain RF. Functional outcomes after surgery for spinal fractures: return to work and activity. Spine (Phila Pa 1976) 29:470–477. discussion Z6. 2004;
19. Meves R, Avanzi O. Correlation among canal compromise, neurologic deficit, and injury severity in thoracolumbar burst fractures. Spine (Phila Pa 1976) 31:2137–2141. 2006;
20. Park SR, Na HY, Kim JM, Eun DC, Son EY. More than 5-Year Follow-up Results of Two-Level and Three-Level Posterior Fixations of Thoracolumbar Burst Fractures with Load-Sharing Scores of Seven and Eight Points. Clin Orthop Surg 8:71–77. 2016;
21. Rabie A, Ibrahim AM, Lee BT, Lin SJ. Use of intraoperative computed tomography in complex facial fracture reduction and fixation. J Craniofac Surg 22:1466–1467. 2011;
22. Sasso RC, Best NM, Reilly TM, McGuire RA Jr. Anterior-only stabilization of three-column thoracolumbar injuries. J Spinal Disord Tech 18 Suppl:S7–S14. 2005;
23. Schwab FJ, Blondel B, Bess S, Hostin R, Shaffrey CI, Smith JS, et al. Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis. Spine (Phila Pa 1976) 38:E803–E812. 2013;
24. Seo DK, Kim CH, Jung SK, Kim MK, Choi SJ, Park JH. Analysis of the Risk Factors for Unfavorable Radiologic Outcomes after Fusion Surgery in Thoracolumbar Burst Fracture : What Amount of Postoperative Thoracolumbar Kyphosis Correction is Reasonable? J Korean Neurosurg Soc 62:96–105. 2019;
25. Sokolowski MJ, Garvey TA, Perl J, Sokolowski MS, Cho W, Mehbod AA, et al. Prospective study of postoperative lumbar epidural hematoma: incidence and risk factors. Spine (Phila Pa 1976) 33:108–113. 2008;
26. Wang F, Zhu Y. Treatment of complete fracture-dislocation of thoracolumbar spine. J Spinal Disord Tech 26:421–426. 2013;
27. Whang PG, Vaccaro AR. Thoracolumbar fracture: posterior instrumentation using distraction and ligamentotaxis reduction. J Am Acad Orthop Surg 15:695–701. 2007;
28. 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 18 Suppl:S15–S23. 2005;
29. Xu N, Yu M, Liu X, Sun C, Chen Z, Liu Z. A systematic review of complications in thoracic spine surgery for ossification of the posterior longitudinal ligament. Eur Spine J 26:1803–1809. 2017;
30. Yoshihara H. Indirect decompression in spinal surgery. J Clin Neurosci 44:63–68. 2017;

Article information Continued

Fig. 1.

A T12-L1 rod was distracted for the purpose of L1 indirect vertebral body decompression in patients with L1 burst fractures.

Fig. 2.

Dural compression ratios were calculated using the following equation: (1−C/[A+B]/2)×100. We evaluated (A) the dura mater at the cephalad non-compressed level, (B) the dura mater at the caudal non-compressed level, and (C) the dura mater at the injury level.

Fig. 3.

Comparison of the vertebral body and thoracolumbar junction before and after surgery (24 months). Comparison of angular changes between the direct decompression surgery group using lateral X-ray (A, preoperative; B, 24 months postoperative) and the indirect decompression surgery group (C, preoperative; D, 24 months postoperative).

Table 1.

Comparative descriptive statistics with respect to medical and demographic variables

Group Group 1 (indirect decompression) Group 2 (direct decompression) p-value
Age 62.15 ± 9.50 60.52 ± 10.41 0.61
Sex 0.47
 Male 17 19
 Female 12 9
Hypertension (%) 34.3 37.1 0.81
Diabetes mellitus (%) 12.5 25.7 0.21
Smoking (%) 34.3 34.2 0.97
BMI 24.00 ± 3.24 24.58 ± 3.48 0.48
BMD -1.38 ± 1.69 -1.49 ± 1.72 0.81
Injured vertebra 0.61
 T11 4 6
 T12 11 3
 L1 8 8
 L2 6 11

The data is presented as number or mean ± standard deviation.

BMI: body mass index; BMD: bone marrow density.

Table 2.

Comparison of surgical time, intraoperative bleeding, and surgical factors between the 2 groups

Group (surgical method) Group 1 (indirect decompression) Group 2 (direct decompression) p-value
Operation time (min) 126.06 ± 44.92 157.39 ± 61.26 0.03
Intraoperative blood loss (mL) 427.58 ± 239.63 603.57 ± 515.12 0.11
Fusion level 3.41 ± 0.50 3.32 ± 0.47 0.47
Dural compression ratio 0.27 ± 0.14 0.29 ± 0.10 0.55

Table 3.

Clinical outcomes during the study follow-up period of both groups

Group (surgical method) Group 1 (indirect decompression) Group 2 (direct decompression) p-value
VAS (back)
 Preoperative 8.37 ± 0.67 8.50 ± 0.96 0.58
 Immediately postoperative 5.58 ± 1.99 5.10 ± 1.91 0.35
 Final follow-up 3.00 ± 2.03 3.64 ± 2.02 0.23
VAS (leg)
 Preoperative 7.86 ± 1.12 7.03 ± 2.25 0.08
 Immediately postoperative 3.51 ± 1.74 4.10 ± 2.49 0.30
 Final follow-up 2.82 ± 1.53 3.25 ± 2.35 0.42
ODI score
 Preoperative 38.06 ± 5.30 39.71 ± 5.53 0.25
 Immediately postoperative 22.86 ± 5.33 22.82 ± 9.34 0.98
 Final follow-up 9.86 ± 3.93 14.85 ± 9.37 0.03

VAS: visual analog scale; ODI: Oswestry Disability Index.

Table 4.

Comparative radiologic parameters between the surgical groups

Group (surgery method) Group 1 (indirect decompression) Group 2 (direct decompression) p-value
Angle of the thoracolumbar junction
 Preoperative 17.82 ± 10.05 17.28 ± 8.24 0.81
 Immediately postoperative 6.85 ± 4.17 10.51 ± 7.33 0.02
 2 years (final follow-up) 8.89 ± 5.39 13.51 ± 5.72 0.01
Thoracic kyphosis
 Preoperative 30.75 ± 10.92 30.21 ± 10.65 0.85
 Immediately postoperative 17.68 ± 7.68 19.57 ± 8.69 0.39
 2 years (final follow-up) 24.62 ± 8.97 25.53 ± 9.48 0.39
Lumbar lordosis
 Preoperative 35.79 ± 8.85 37.28 ± 11.42 0.58
 Immediately postoperative 44.34 ± 6.01 43.27 ± 9.63 0.58
 2 years (final follow-up) 39.08 ± 8.21 41.10 ± 6.29 0.31
PI-LL mismatch
 Preoperative 27.83 ± 10.10 27.52 ± 10.55 0.58
 Immediately postoperative 20.75 ± 11.02 22.81 ± 10.87 0.44
 2 years (final follow-up) 20.84 ± 11.01 26.51 ± 11.13 0.02
Wedge angle of injured vertebral body
 Preoperative 19.55 ± 8.21 19.46 ± 6.97 0.96
 Immediately postoperative 7.53 ± 4.79 12.17 ± 8.71 0.01
 2 years (final follow-up) 8.24 ± 7.00 12.60 ± 4.69 0.01

PI: pelvic incidence; LL: lumbar lordosis.