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v.v. rerikh, v.d. sinyavin, 2022
comparative analysis of hybrid stabilization methods in the treatment of burst fractures of the vertebral bodies associated with osteoporosis
V.V. Rerikh, V.D. Sinyavin
Novosibirsk Research Institute of Traumatology and Orthopaedics n.a. Ya.L. Tsivyan, Novosibirsk, Russia
Objective. To perform comparative analysis of posterior stabilization methods combined with cement vertebroplasty and osteoplasty with deproteinized bone allograft in the treatment of uncomplicated burst fractures of the vertebral bodies associated with osteoporosis. Material and Methods. The study was a retrospective analysis. Two groups of patients were formed, inclusion and exclusion criteria were determined. The follow-up period was 12 months. The magnitude of kyphosis correction according to the Cobb method, the magnitude of residual postoperative kyphotic deformity, its recurrence in the long term postoperative period, and the length of transpedicular fixation were assessed. Sagittal balance parameters and subjective assessments of the patient's condition were not evaluated.
Results. With a statistically significant difference, it can be said that the main predictors of recurrence of local kyphosis, incomplete correction of deformity and increased pain syndrome are the level of injury (T12 vertebra), the degree of initial kyphotic deformity, incomplete achievement of its correction after surgery (>10°), and the value of T-criterion according to densitometry. The length of fixation does not affect the loss of correction and recurrence of kyphosis, however it may correlate with the severity of osteoporosis.
Conclusions. When comparing posterior stabilization methods in combination with cement vertebroplasty or osteoplasty, there was no statistical difference in clinical and radiological outcomes.
Key Words: burst fractures, osteoporosis, hybrid stabilizaion, vertebroplasty, osteoplasty, kyphosis.
Please cite this paper as: Rerikh VV, Sinyavin VD. Comparative analysis of hybrid stabilization methods in the treatment of burst fractures of the vertebral bodies associated with osteoporosis. Hir. Pozvonoc. 2022;19(4):40—45. In Russian. DOI: http://dx.doi.org/10.14531/ss2022A.40-45.
Surgical treatment of vertebral fractures in the elderly is widespread [1] due to the technique of posterior stabilization, which is characterized by minimal trauma and a positive primary effect. However, due to the axial load, the fixation is often unstable, which is especially typical for elderly patients with low bone mineral density [2, 3]. To prevent this complication, in recent years, attempts have been made to plasticize the damaged vertebral body with bone cement or bone allograft - deproteinized bone matrix (DBM) in combination with posterior fixation, which provides circular stabilization of the damaged segment. Nevertheless, it is still not clear which method is superior in the treatment of osteoporotic fractures. Several studies [4, 5] have reported satisfactory results of posterior stabilization combined with vertebroplasty to restore vertebral body height and reduce pain, which is
even recommended as an alternative to anterior stabilization [6, 7]. However, the most common complication of vertebroplasty (migration of bone cement into the venous system and spinal canal) can cause thromboembolic complications and compression of neural structures [8, 9]. This restricts its application to vertebral body burst fractures. Osteoplasty of the injured vertebral body with posterior fixation is also used [10, 11]. The number of studies directly comparing these methods is small, and the evidence is insufficient. It is also important that there is no clear understanding of the factors that influence the loss of correction and recurrence of kyphotic deformity in patients with osteoporosis.
The objective is to perform a comparative analysis of hybrid stabilization methods (transpedicular fixation combined with cement plasty of injured vertebral body and transpedicular fixation
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combined with osteoplasty) in the treatment of vertebral body fractures associated with osteoporosis.
Material and Methods
The tasks of the retrospective study included the analysis of hybrid stabilization methods and the identification of possible predictors of incomplete correction of kyphotic deformity and recurrence of local kyphosis.
Inclusion criteria: uncomplicated complete and incomplete burst fractures (types A3, A4 according to AOSpine) of the thoracolumbar vertebral bodies (T10-L2) associated with osteoporosis of the spine with a T-score of -2.5 and lower according to densitometry; absence of bone-seeking therapy before surgery and in the postoperative period with a follow-up period of at least 12 months. Exclusion criteria: complicated spinal injuries and secondary osteoporosis.
v.v. rerikh, v.d. sinyavin. methods of hybrid stabilization in the treatment of burst fractures of the vertebral bodies
Patients
In 2016-2021, a total of 2,351 patients were operated on at the Spinal Pathology Department of the Novosibirsk Research Institute of Traumatology and Orthopaedics n.a. Ya.L. Tsivyan. A total of 197 patients were diagnosed with osteoporosis, including 171 with incomplete and complete burst fractures and 149 with a thoracolumbar level of injury. From this number, 74 patients who underwent hybrid stabilization were chosen for the study: in 25 cases - posterior stabilization in combination with cement plasty of the injured vertebral body (Group 1), and in 49 cases - posterior stabilization in combination with osteoplasty (Group 2). The average time from the moment of injury to surgery was 15 ± 7 days. Additional cement augmentation of the screws in the groups was not performed.
Techniques
The magnitude of kyphosis correction (according to the Cobb) and that of postoperative kyphotic deformity were assessed. The correction was considered incomplete, if it was more than 5°. Recurrence of deformity was estimated at 4, 6, 12 months. The deformity was assumed to be recurrent if it increased by more than 5° throughout the postoperative follow-up (the error in the accuracy of X-ray measurements of intersegmental relations is 5°). The extent of transpedicular fixation (3-4 segments) was assessed. Subjective assessment of patients' condition and sagittal balance parameters was not taken into account.
Statistical analysis
Descriptive statistics of continuous indicators were calculated as median; for binary indicators, the number of cases in percent [95 % confidence interval of percent] was calculated by the Wilson formula. Normality was checked by Shapiro - Wilk test; Mann - Whitney nonparametric unpaired U test was used between the groups; the displacement of distributions was calculated with the construction of a 95 % confidence interval for the displacement. Predictors of insufficient correction and loss of kypho-sis correction were determined by constructing logistic regression models. Pair-
wise numerical associations were defined by the construction of single-factor models; and multiple numerical associations (predictors) - by multifactor models. Statistical hypotheses were tested at a critical significance level of p = 0.05, that is, the difference was considered statistically significant at p < 0.05.
Results
There was no statistical difference between the groups in age (64.36 ± 6.74 years and 67.08 ± 8.93 years, respectively), the value of the T-score (-3.36 ± 0.51 and -3.18 ± 0.59) and the initial kyphotic deformity (15.76° ± 12.27° and 10.10° ± 7.28°).
According to the injury type (A3 : A4), the distribution in Group 1 was 24.0 : 76.0 %, in Group 2 - 53.1 : 46.9 %. The difference in the kyphosis magnitude after surgery and in the analyzed periods of postoperative follow-up between the groups was not statistically identified (Table 1), as in the magnitude of the deformity correction (p = 0.590).
During the analysis, it was found that the surgical method did not significantly affect either the incomplete correction (p = 0.251) or the recurrence of the deformity (p = 0.034) at all times of follow-up. There was no effect on these criteria of the injury morphology and the length of the posterior instrumentation (1.01 [0.63; 1.82]; p = 0.248 with incomplete correction and 1.41 [0.86; 2.83]; p = 0.240 with recurrent deformity). In the logistic regression model, a slight influence of the T-score and the extent of fixation was observed (Pearson's correlation coefficient 0.15).
Incomplete deformity correction is affected by the injury level (T12 vertebra) as well as the level of the T-score, and the latter is significant up to 6 months after surgery (Table 2). After this period, the severity of osteoporosis does not affect the recurrence of kyphotic deformity, probably due to the consolidation of fractures.
The construction of multifactorial logistic regression models (Tables 3, 4) demonstrated that injury at the level of the T12 vertebra raises the chances of
recurrence of kyphosis in the postoperative period by three times. The magnitude of initial kyphosis is significantly affected if it is greater than 10°. The type of fracture (complete burst) slightly enhances the chances of recurrence. Nevertheless, it is statistically insignificant. It was observed that the value of the T-score with complete deformity correction does not affect the formation of a recurrence of kyphosis during the entire postoperative period.
Fig. 1 and 2 show clinical examples.
Discussion
The purpose of surgical treatment for fractured vertebrae associated with osteoporosis is not only to correct the kyphotic deformity and reduce the pain syndrome in the elderly, but also to prevent possible adverse effects. According to the literature sources of recent years, this aim is achieved through the use of minimally invasive surgical techniques, in particular hybrid stabilization, which in the classical version is a transpedicular fixation in combination with vertebroplasty. Nevertheless, some problems associated with the use of bone cement force researchers to resort to trivial techniques.
For example, Li et al. [10] show the treatment outcomes of burst fractures associated with osteoporosis by performing osteoplasty of the injured vertebral body under posterior fixation conditions. After 3 months of postoperative follow-up, there is a pronounced decrease in pain syndrome, including with prolonged axial loads. The vertebral body height was restored immediately after the surgery. No decrease was observed after 3 months. Also, infectious and neurological complications were not observed, which in total suggests that elderly patients tolerate such interventions well.
In turn, Qin et al. [11] point out that implantation of bone tissue into the vertebral body improves the stability of the entire structure and reduces the pain syndrome. The frequency of vertebral height loss in the postoperative period, beginning from the 6th month, the recurrence of local kyphosis and instru-
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v.v. rerikh, v.d. sinyavin. methods of hybrid stabilization in the treatment of burst fractures of the vertebral bodies
mentation instability were higher during these interventions than with isolated short-segment fixation (p < 0.05). Satisfactory outcomes of the technique are also confirmed by biomechanical tests [12].
There was no statistical difference in radiological outcomes in our study when comparing two surgical techniques. All patients had no complications during the entire follow-up period. Statistically significant predictors of the recurrence
of local kyphosis and increased pain syndrome are the level of injury (T12 vertebra), the degree of initial kyphotic deformity (more than 10°) and its incomplete correction after surgery, and the value of the T-score according to densitometry. The extent of the transpedicular system has no statistically significant effect on the possibility of kyphosis recurrence. However, it should be noted that the severity of osteoporosis influences the length of the transpedicular system: the
more severe osteoporosis is, the more important is extended fixation, as shown in the literature [13, 14].
Despite the absence of any difference between the techniques, it is more appropriate to use osteoplasty with deproteinized bone allograft to eliminate the risks arising from the introduction of bone cement into the vertebral body, as well as due to the influence of the toxicity of bone cement and an augmentation of the osteoresorption area
Table 1 Comparison of the magnitude of kyphosis in groups of patients before the surgery and at follow-up control times
Follow-up period Vertebroplasty +TPF (n = 25) Osteoplasty +TPF (n = 49) Difference (effect size) MED [95 % CI]: SMD [95 % CI] Mann — Whitney U test; p-level
Before surgery 14 [8; 20] 15.76 ± 12.27 12 [6; 15] 10.10 ± 7.28 psevdo MED [95 % CI]: -4.00 [-8.00; 0.00] SMD [95 % CI]: 0.61 [0.12; 1.10] 0.062
After surgery 1 [0; 5] 1.04 ± 3.17 0 [0; 2] 0.20 ± 1.66 psevdo MED [95 % CI]: -1.00 [-3.00; 0.00] SMD [95%CI]: 0.45 [-0.04; 0.94] 0.115
4 months after surgery 1 [0; 5] 2.12 ± 3.09 0 [0; 5] 0.45 ± 4.52 psevdo MED [95 % CI]: 0 [-3.00; 1.00] SMD [95 % CI]: 0.12 [-0.36; 0.60] 0.533
6 months after surgery 1 [0; 6] 2.44 ± 3.38 1 [0; 6] 1.92 ± 6.62 psevdo MED [95 % CI]: 0.00 [-3.00; 1.00] SMD [95 % CI]: 0.09 [-0.39; 0.57] 0.815
12 months after surgery 2 [0; 6] 2.00 ± 4.17 2 [0; 6] 2.27 ± 6.88 psevdo MED [95 % CI]: 0.00 [-3.00; 2.00] SMD [95 % CI]: 0.12 [-0.36; 0.60] 0.689
TPF — transpedicular fixation; MED — median; SMD — standardized mean difference.
Table 2
Logistic regression models of incomplete kyphosis correction in all patients
Covariants Single-factor models Multifactor models
OR [95 % CI] p OR [95 % CI] p
T12 level 5.96 [1.48; 30.10] 0.016 5.01 [1.20; 26.01] 0.035
Initial kyphosis more than 10° 7.46 [1.29; 141.63] 0.064 6.05 [0.98; 117.13] 0.103
T-score 2.42 [0.79; 7.72] 0.116 - -
Fixation length 2,95 [0,38; 16,50] 0,238 - -
Table 3 Logistic regression models of kyphosis recurrence at 4, 6, 12 months after surgery with co mplete deformity correction in all patients
Covariants Single-factor models Multifactor optimal model
OR [95 % CI] p OR [95 % CI] p
Initial kyphosis more than 10° 12.16 [2.21; 227.87] 0.019 17.48 [2.59; 375.46] 0.015
T12 level 3.37 [1.03; 11.68] 0.047 3.31 [0.82; 15.35] 0.102
T-score 0.48 [0.13; 1.43] 0.221 0.18 [0.03; 0.77] 0.036
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v.v. rerikh, v.d. sinyavin. methods of hybrid stabilization in the treatment of burst fractures of the vertebral bodies
Table 4
Logistic regression models of kyphosis recurrence at 4, 6, 12 months after surgery with incomplete deformity correction in all patients
Covariants Single-factor models Multifactor optimal model
OR [95 % CI] P OR [95 % CI] P
T-score 0.31 [0.08; 1.00] 0.071 0.33 [0.08; 1.10] 0.102
Kyphosis more than 10° after surgery 2.17 [0.66; 8.54] 0.227 3.08 [0.85; 13.48] 0.104
T12 level 1.40 [0.42; 4.48] 0.570 - -
at the border of the bone-cement contact. This is especially true for complete burst fractures. The question of whether sagittal profile disruption is a predictor of post-traumatic deformity recurrence in osteoporotic fractures remains open, which may prompt further research.
Conclusion
In the course of the study, there was no statistical difference detected in radiological outcomes between the techniques of cement vertebroplasty and osteoplasty in combination with posterior stabilization in the treatment of burst fractures associated with osteoporosis. There was no effect of the technique on the loss of correction in the long-term period either. Nevertheless, the presence of such predictors as injury to the T12 vertebra, the magnitude of initial kyphotic deformity, and the persistence of residual kyphosis of more than 10° after surgery increase the risk of recurrence of kyphotic deformity with both techniques.
Study limitations: the small patient sampling did not allow for long-term analysis of the effect of sagittal imbalance on outcomes, so this issue was not included in the study objectives.
The study had no sponsors. The authors declare that they have no conflict of interest. The study was approved by the institution's local ethics committee.
All authors contributed significantly to the research and preparation of the article, read and approved the final version before publication.
Fig. 1
CT and radiographs of a 55-year-old female patient with a complete burst fracture of the T12 vertebral body: a - post-traumatic kyphosis at the level of T11-T12 - 17°; spinal osteoporosis (T-score -3.9); b - condition after cement vertebroplasty of the body of the T12 vertebra, extended posterior stabilization, correction of kyphosis
4MMRE
b
Fig. 2
CT and radiographs of a 64-year-old female patient with a complete burst fracture of the L2 vertebral body, spinal osteoporosis (T-score -3.1): a - before the surgery; b - after the osteoplasty of L2 vertebra with a bone allograft, extended posterior stabilization; c - 12 months after the surgery
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v.v. rerikh, v.d. sinyavin. methods of hybrid stabilization in the treatment of burst fractures of the vertebral bodies
References
1. Bu BX, Wang MJ, Liu WF, Wang YS, Tan HL. Short-segment posterior instrumentation combined with calcium sulfate cement vertebroplasty for thoracolumbar compression fractures: radiographic outcomes including nonunion and other complications. Orthop Trau-matol Surg Res. 2015;101:227-233. DOI: 10.1016/j.otsr.2014.11.019.
2. Blizzard DJ, Hills CP, Isaacs RE, Brown CR. Extreme lateral interbody fusion with posterior instrumentation for spondylodiscitis. J Clin Neurosci. 2015;22:1758-1761. DOI: 10.1016/j.jocn.2015.05.021.
3. Xiao ZL, Shan YX, Hu SS, Wu T, Sun H. Curative effect of transpedicular intervertebral bone graft after posterior pedicle screw fixation of thoracolumbar fractures in senile-osteo-porotic vertebral fracture patients. Prog Mod Biomed 2014;14:4491-4493. DOI: 10.13241/j. cnkipmb.2014.23.024.
4. Xu Z, Xu W, Wang C, Luo H, Li G, Chen R. [Effectiveness of long segment fixation combined with vertebroplasty for severe osteoporotic thoracolumbar compressive fractures]. ZhongguoXiu Fu Chong Jian Wai Ke Za Zhi. 2013;27:1331-1337. Chinese.
5. Li Z, Wang Y, Xu Y, Xu W, Zhu X, Chen C. Efficacy analysis of percutaneous pedicle screw fixation combined with percutaneous vertebroplasty in the treatment of osteoporotic vertebral compression fractures with kyphosis. J Orthop Surg Res. 2020;15:53. DOI: 10.1186/ s13018-020-1583-1.
6. Spiegl UJ, Anemuller C, Jarvers JS, von der Höh N, Josten C, Heyde CE. Hybrid stabilization of unstable osteoporotic thoracolumbar vertebral body fractures: clinical and radiological outcome after a mean of 4 years. Eur Spine J. 2019;28:1130-1137. DOI: 10.1007/ s00586-019-05957-8.
7. Schnake KJ, Scheyerer MJ, Spiegl UJA, Perl M, Ullrich BW, Grüninger S, Osterhoff G, Katscher S, Sprengel K. [Minimally invasive stabilization of thoracolumbar osteoporotic fractures]. Unfallchirurg. 2020;123:764-773. German. DOI: 10.1007/ s00113-020-00835-1.
8. Robinson Y, Tschoke SK, Stahel PF, Kayser R, Heyde CE. Complications and safety aspects of kyphoplasty for osteoporotic vertebral fractures: a prospective follow-up study in 102 consecutive patients. Patient Saf Surg. 2008;2:2. DOI: 10.1186/1754-9493-2-2.
9. Zhang Z, Jing Q, Qiao R, Yang J, Chen H, Qian L, Zhang X, Yang J, Hao D. [Risk factors analysis of adjacent fractures after percutaneous vertebroplasty for osteoporotic ver-
tebral compression fracture]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2021;35:20-25. Chinese. DOI: 10.7507/1002-1892.202008044.
10. Li D, Huang Y, Yang H, Sun T, Wu Y, Li X, Chen L. Short-segment pedicle instrumentation with transpedicular bone grafting for nonunion of osteoporotic vertebral fractures involving the posterior edge. Eur J Orthop Surg Traumatol. 2013;23:21-26. DOI: 10.1007/s00590-011-0928-1.
11. Qin Z, Liu H, Chen G, Liu G, Zhang P, Zhu H. Transpedical interbody bone grafting in the treatment of senile osteoporotic vertebral fracture. Pak J Med Sci. 2017;33:1166-1170. DOI: 10.12669/pjms.335.12908.
12. Jia C, Zhang R, Xing T, Gao H, Li H, Dong F, Zhang J, Ge P, Song P, Xu P, Zhang H, Shen C. Biomechanical properties of pedicle screw fixation augmented with allograft bone particles in osteoporotic vertebrae: different sizes and amounts. Spine J. 2019;19:1443-1452. DOI: 10.1016/j.spinee.2019.04.013.
13. Hartensuer R, Gehweiler D, Schulze M, Matuszewski L, Raschke MJ, Vordemvenne T. Biomechanical evaluation of combined short segment fixation and augmentation of incomplete osteoporotic burst fractures. BMC Musculoskelet Disord. 2013;14:360. DOI: 10.1186/1471-2474-14-360.
14. Homagk L, Hellweger A, Hofmann GO. [Hybrid stabilization and geriatric complex treatment of type A spinal fractures]. Chirurg. 2020;91(10):878-885. German. DOI: 10.1007/s00104-020-01136-4.
Address correspondence to:
Rerikh Viktor Viktorovich
Novosibirsk Research Institute of Traumatology and Orthopaedics n.a. Ya.L. Tsivyan,
17 Frunze str., Novosibirsk, 630091, Russia, clinic@niito.ru
Received 21.07.2022 Review completed 17.10.2022 Passed for printing 21.10.2022
Viktor Viktorovich Rerikh, DMSc, Head of the Research Department of Spine Pathology, Novosibirsk Research Institute of Traumatology and Orthopaedics n.a. Ya.L. Tsivyan, 17Frunze str., Novosibirsk, 630091, Russia, ORCID: 0000-0001-8545-0024, clinic@niito.ru;
Vladimir Dmitryevich Sinyavin, orthopedic traumatologist, postgraduate student, Novosibirsk Research Institute of Traumatology and Orthopaedics n.a. Ya.L. Tsivyan, 17Frunze str., Novosibirsk, 630091, Russia, ORCID: 0000-0001-5237-6403, Dr.VladimirSinyavin@gmail.com.
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spine injuries
