Load-sharing Score Research Articles

Traumatic thoracic spine fracture: can we predict when MRI would modify the fracture classification or decision-making compared to CT alone?

To determine the impact of magnetic resonance imaging (MRI) on fracture classification for thoracic spine fractures (TSFs) compared to computed tomography (CT) alone. This study was a retrospective review of 63 consecutive patients with TSFs who underwent CT and MRI within ten days of injury. Three reviewers classified all fractures according to the AOSpine Classification and the ThoracolumbarAOSpineInjury severity score (TLAOSIS). Posterior ligamentous complex (PLC) injury on MRI was defined by "black stripe discontinuity" and on CT by the presence of vertebral body translation, facet joint malalignment, horizontal laminar or spinous process fracture, and interspinous widening. The proportion of patients with AO type A/B/C and with TLAOSIS ≤ 5 and ≥ 6 was compared between CT and MRI. Classification and regression trees were used to create a series of predictive models for the probability of PLC injury in AO type A fractures. AO classification using CT was as follows: type A in 35 patients (55%), type B in 18 patients (29%), and type C in 10 patients (16%). Thirty-threepatients (52%) had a TLAOSIS ≤5, while the remaining 30 (48%) had TLAOSI ≥6. The addition of MRI after CT upgraded type A to type Bfractures in 10 patients (16%) and changed TL AOSIS from ≤5 to ≥6 in8 cases (12.8%). Type A fractures with load sharing score (LSC) ≥6 had a 60% chance of upgrading to type B, while LSC <6 had a 12.5% chance of upgrading to type B. CT yielded (89%) accuracyin diagnosing PLC injury in TSFs. The addition of MRI after CTsubstantially changed the AO classification or TLAOISS, compared to CT alone, thus suggesting an added value of MRI for PLC assessment for TSFs classification.

Short segment posterior fixation of unstable thoracolumbar vertebral fractures with fractured vertebra augmentation with intermediate pedicle screw - a clinicoradiological analysis.

Unstable thoracolumbar burst fractures are routinely encountered in orthopedic practice. Recently, short-segment fixation with pedicle screw augmentation of the fractured vertebra for unstable thoracolumbar burst fractures has gained popularity. Nonetheless, the maintenance of the kyphotic correction during the follow-up period remains controversial. This study aimed to examine the clinical-radiological outcomes, complications, and functional outcomes of fractured vertebrae augmentation with intermediate pedicle screws in short-segment instrumentation in acute thoracolumbar spine fractures. This retrospective study was conducted in the Department of Orthopedics, All India Institute of Medical Sciences, Jodhpur, using medical records from January 2021 to October 2022. Parameters such as local kyphosis correction, loss of kyphotic correction at final follow-up, anterior body height correction (%), and loss of correction (%) at final follow-up were measured as primary outcomes. Various other parameters such as operative time, blood loss, length of hospital stay, and visual analog scale were measured as secondary outcomes. The mean correction obtained via surgery in the immediate postoperative period was 13.7±2.3 degrees. The mean loss of correction at the final follow-up was 4.1±2.0 degrees, and the mean final local kyphotic angle was 7.2±2.4 degrees (P<0.05). The mean correction obtained via surgery in the immediate postoperative period was 37.2%±9.0%. The mean loss of correction at the final follow-up was 10.5%±5.3%, and the mean final anterior vertebral body height maintained was 72%±11.0% (P<0.05). Short-segment posterior fixation with pedicle screw augmentation achieves good correction of local kyphotic angle and anterior vertebral height in the immediate postoperative period, but some loss of correction at final follow-up is common. In our study, the loss of correction corresponded directly to the load-sharing score.

Risk factors for insufficient reduction after short-segment posterior fixation for thoracolumbar burst fractures: Does the interval from injury onset to surgery affect reduction of fractured vertebrae?

BackgroundMany surgeons have encountered patients who could not immediately undergo surgery to treat spinal fractures because they had associated injuries and/or because a complete diagnosis was delayed. For such patients, practitioners might assume that delays could mean that the eventual reduction would be insufficient. However, no report covered risk factors for insufficient reduction of fractured vertebra including duration from injury onset to surgery. The purpose of this study is to investigate the risk factors for insufficient reduction after short-segment fixation of thoracolumbar burst fractures.MethodsOur multicenter study included 253 patients who sustained a single thoracolumbar burst fracture and underwent short-segment fixation. We measured the local vertebral body angle (VBA) on roentgenograms, before and after surgery, and then calculated the reduction angle and reduction rate of the fractured vertebra by using the following formula: left[ {left( {{text{Preoperative}};{text{VBA }}{-}{text{ Postoperative}};{text{VBA}}} right)/{text{Preoperative}};{text{VBA}}} right] , times , 100. A multiple logistical regression analysis was performed to identify risk factors for insufficient reduction. The factors that we evaluated were age, gender, affected spine level, time elapsed from injury to surgery, inclusion of vertebroplasty with surgery, load-sharing score (LSS), AO classification (type A or B), preoperative VBA, and the ratio of canal compromise before surgery.ResultsThere were 140 male and 113 female patients, with an average age of 43 years, and the mean time elapsed between injury and surgery was 3.8 days. The mean reduction angle was 12°, and the mean reduction rate was 76%. The mean LSS was 6.4 points. Multiple linear regression analysis revealed that a higher LSS, a larger preoperative VBA, a younger age, and being female disposed patients to having a larger reduction angle and reduction rate. The time elapsed from injury to surgery had no relation to the quality of fracture reduction in the acute period.ConclusionsOur findings indicate that if there is no neurologic deficit, we might not need to hurry surgical reduction of fractured vertebrae in the acute phase.

Risk Factors for Postoperative Loss of Correction in Thoracolumbar Injuries Caused by High-Energy Trauma Treated via Percutaneous Posterior Stabilization without Bone Fusion.

Background and Objectives: Percutaneous pedicle screws were first introduced in 2001, soon becoming the cornerstone of minimally invasive spinal stabilization. Use of the procedure allowed adequate reduction and stabilization of spinal injuries, even in severely injured patients. This decreased bleeding and shortened surgical time, thereby optimizing outcomes; however, postoperative correction loss and kyphosis still occurred in some cases. Thus, we investigated cases of percutaneous posterior fixation for thoracolumbar injury and examined the factors affecting the loss of correction. Materials and Methods: Sixty-seven patients who had undergone percutaneous posterior fixation for thoracolumbar injury (AO classifications A3, A4, B, and C) between 2009 and 2016 were included. Patients with a local kyphosis angle difference ≥10° on computed tomography at the postoperative follow-up (over 12 months after surgery) or those requiring additional surgery for interbody fusion were included in the correction loss group (n = 23); the no-loss group (n = 44) served as the control. The degree of injury (injury level, AO classification, load-sharing score, local kyphosis angle, cuneiform deformity angle, and cranial and caudal disc injury) and surgical content (number of fixed intervertebral vertebrae, type of screw used, presence/absence of screw insertion into the injured vertebrae, and presence/absence of vertebral formation) were evaluated as factors of correctional loss and compared between the two groups. Results: Comparison between each group revealed that differences in the wedge-shaped deformation angle, load-sharing score, degree of cranial disc damage, AO classification at the time of injury, and use of polyaxial screws were statistically significant. Logistic regression analysis showed that the differences in wedge-shaped deformation angle, AO classification, and cranial disc injury were statistically significant; no other factors with statistically significant differences were found. Conclusion: Correction loss was seen in cases with damage to the cranial intervertebral disc as well as the vertebral body.

Imageology study of correlation loss and its related factors after short-segment pedicle screw reduction and fixation for lumbar fractures

To analyze the correction loss after posterior segmental fixation for lumbar spine fractures and explore the related image factors. Posterior short-segment fixation was received in 48 patients with L2-L4 fractures. There were 32 males and 16 females, with ages of 23 to 60 (45.98±8.20) yeaes. The anterior vertebrae height (AVH), vertebral wedge angle (VWA) of the injured vertebra and local kyphosis angle (LKA) were measured before operation, 1 week after operation and the final follow-up. The loss of segmental discal angle (LoSDA), LKA(LoLKA), AVH(LoAVH) were calculated between 1 week postoperative and the last follow up. Preoperative load-sharing scores(LSS), TLICS scores, and adjacent intervertebral disc injuries (IDIs) were assessed. Then the correlation between the age, follow up time, LSS, TLICS, IDIs and the correction loss was analyzed. The average follow-up was 12 to 18 (16.13±5.39) months. LKA, AVH and VWA at 1 week postoperative and those at the final follow up, were significantly improved compared with those preoperative (P<0.05). In the final follow up, the average LKA(5.70±3.17)° and AVH(4.31±5.95)% correction loss were observed compared with those 1 week postoperative(P<0.05). Otherwise the lose of VWA was not obvious(P>0.05). Univariate analysis showed that the SDA (r=0.706, 0.579, 0.449) and LKA(r=0.715, 0.566, 0.502) correction loss were aggravated with the increase of LSS, TLICS and IDIs, and AVH (r=-0.325, -0.219) correction loss was aggravated with the increase of LSS and TLICS(P<0.05). Multivariate analysis showed that increased LSS scores were all risk factors for segmental disc angle (SDA) loss, LKA correction loss, and AVH correction loss (P<0.05). The angle of adjacent intervertebral discs and anterior height of injured vertebrae were lost statistically after posterior short-segment pedicle screw treatment for lumbar fractures, and multivariate analysis showed that all of them were correlated with load-sharing score.

Thoracolumbar Burst Fracture: McCormack Load-sharing Classification: Systematic Review and Single-arm Meta-analysis.

A systematic review and single-arm meta-analysis of randomized clinical trials. The aim of this study was to evaluate whether the load-sharing classification (LSC) is reliable to predict the best surgical approach for thoracolumbar burst fracture (TBF). There is no previous review evaluating the efficacy of the use of LSC as a guide in the surgical treatment of burst fractures. On April 19th, 2019, a broad search was performed in the following databases: EMBASE, PubMed, Cochrane, SCOPUS, Web of Science, LILACS, and gray literature. This study was registered on the International Prospective Register of Systematic Reviews. We included clinical trials involving patients with TBF undergoing posterior surgical treatment, classified by load-sharing score, and that enabled the analysis of the outcomes loss of segmental kyphosis and implant failure (IF). We performed random- or fixed-effects models meta-analyses depending on the data homogeneity. Heterogeneity between studies was estimated by I2 and τ2 statistics. The search identified 189 references, out of which nine studies were eligible for this review. All articles presenting LSC up to 6 proved to be reliable in indicating that only posterior instrumentation is necessary, without screw failures or loss of kyphosis correction. For cases where the LSC was >6, only 2.5% of the individuals presented IF upon posterior approach alone. For loss of kyphosis correction, only 5% of patients had this outcome where LSC >6. For both outcomes together, we had 6% of postoperative problems (I2 = 77%, τ2 < 0.0015, P < 0.01). Load-sharing scores up to 6 are 100% reliable, only requiring posterior instrumentation for stabilization. For scores >6, the risk of implant breakage and loss of kyphosis correction in posterior fixation alone is low. Thus, other factors should be considered to define the best surgical approach to be adopted.Level of Evidence: 1.

Outcomes of Including Fracture Level in Short- Segment Fixation for Th oracolumbar Fracture Dislocation.

Study DesignThis was a prospective study of 50 patients of thoracolumbar fracture dislocation treated at a single institution with short-segment fixation with the inclusion of fracture level.PurposeTo assess the outcomes of including the fracture level in short-segment fixation for thoracolumbar fracture dislocation. Overview of LiteratureTraditionally, thoracolumbar fracture dislocation is treated with long-segment posterior fixation. However, to save motion segments, short-segment fixation has been used instead in many cases of thoracolumbar trauma.MethodsIn this study, 50 patients with thoracolumbar fracture dislocation were treated with short-segment fixation with inclusion of the fracture level; patients with pathological fractures or with a McCormack load-sharing score >6 were excluded. The 50 patients were prospectively followed for at least 1 year. The duration of surgery, blood loss, and complications were noted. The Visual Analog Scale (VAS) score was used to measure pain, and the American Spinal Injury Association (ASIA) scale was used to determine the neurological status at follow-up. Preoperative, immediate postoperative, and final follow-up X-rays were used to measure the kyphotic angle using Cobb’s method.ResultsThe mean age of our patients was 33.4 years, and the male:female ratio was 1.9:1. The mean follow-up period was 18.4 months (range, 12–23 months). Injuries were mainly at the thoracolumbar junction area (T11–L2, 41 cases, 82%). The average duration of surgery was 94.6 minutes, and the average blood loss was 394.8 mL. Postoperative infection occurred in two cases and implant failure in one case. The kyphosis angle values were as follows: average preoperative, 26.80°±14.50°; immediate postoperative, 4.30°±8.70°; and final follow-up, 5.50°±110°. The ASIA scale and VAS score at final follow-up showed improvement.ConclusionsInclusion of the fracture level in short-segment fixation for thoracolumbar fracture dislocation (McCormack load-sharing score ≤6) gives good kyphosis correction and correction maintenance. It can also obviate the need for traditional long-segment fixation.

Efficacy of modified 270°spinal canal decompression combined with one-stage pedicle screw fixation and vertebral reconstruction for severe thoracolumbar fractures

Objective To investigate the efficacy of modified 270°spinal canal decompression combined with one-stage pedicle screw fixation and vertebral reconstruction for severe thoracolumbar fractures. Methods A retrospective case-control study was made on 44 cases of severe thoracolumbar fractures treated from January 2009 to June 2014. There were 34 males and 10 females, with age range of 20-68 years (mean, 37.9 years). The injured vertebrae included T11/12 in one case, T12-L1 in 10, L1/2 in 21, L2/3 in nine and L3/4 in three. Injury type was all AO type B2. According to the American Spinal Injury Association (ASIA), neurological deficit was Grade A in three cases, Grade B in five, Grade C in 22, and Grade D in 14. Load sharing score (LSC) was 7-9 points (mean, 8.1 points), while the thoracolumbar injury classification and severity score (TLICS) was 7-9 points (mean, 8.2 points). According to the difference of surgical procedures, all cases were divided into traditional group (21 cases) and improved group (23 cases). The patients in traditional group were treated by 270° spinal canal decompression combined with one-stage pedicle screw fixation and vertebral reconstruction, and those in improved group were treated by modified 270°spinal canal decompression combined with one-stage pedicle screw fixation and vertebral reconstruction. Between-group differences were compared with regard to operation time, intraoperative blood loss, postoperative drainage, allogeneic blood transfusion, pain visual analogue scale (VAS) at postoperative 72 hours, Cobb angle, anterior vertebral height, spinal canal compromise, Denis score, work state, neurological function, bone graft fusion and complications. Results Duration of follow-up was (32.4±15.8)months (range, 12-60 months). No wound infection or deterioration of neurological function was found after operation. Operation time was (2.4±0.5)hours in traditional group, less than (2.8±0.6)hours in improved group (P 0.05). VAS was (3.2±0.9)points in traditional group and (3.3±0.9)points in improved group at postoperative 72 hours (P>0.05). Cobb angle, anterior vertebral height and spinal canal compromise in both groups obtained well recovery and maintained after operation (P 0.05). At the last follow-up, ASIA Grade A was noted in three cases, Grade C in two, Grade D in 23, and Grade E in 16. Bone union was achieved in all cases, with no implant loosening or breakage observed. Thirteen cases in traditional group were found with residual bone fragments in the spinal canal after surgery, and two of them received revision surgery. Conclusions Either modified or traditional 270° spinal canal decompression combined with one-stage pedicle screw fixation and vertebral reconstruction can attain satisfactory clinical results in treatment of severe thoracolumbar fractures. However, the modified 270°spinal canal decompression can achieve more thorough decompression without reducing stability of the spine. Key words: Spinal fractures; Thoracic vertebrae; Lumbar vertebrae; Fracture fixation, internal

Comparison of short-segment pedicle fixation with versus without inclusion of the fracture level in the treatment of mild thoracolumbar burst fractures

BackgroundA review of the literature showed that posterior short-segment fixation including the fractured vertebra (PSFFV) has better outcomes in the treatment of thoracolumbar burst fractures(TBFs) than patients with short-segment pedicle screw fixation(SSPF) alone. However, its efficacy in mild TBFs with load-sharing scores of 3 and 4 points has not been specifically analyzed. The aim of this study was to compare the clinical, functional and radiologic results of PSFFV with SSPF for mild TBFs and to determine whether the screws in the fractured vetebra were necessary for these patients. MethodsIn this retrospective study, sixty-nine patients with mild TBFs were divided into 2 groups according to the number of instrumented levels. Group A included 34 patients treated by SSPF (four screws:one level above and below the fracture), and Group B included 35 patients treated by PSFFV (six screws: including the fractured vertebra). Clinical and radiologic parameters were evaluated before surgery, after surgery, and at follow-up. They included clinical outcomes: visual analog scale (VAS), Oswestry Disability Index (ODI). Being a radiology-based study, the radiologic measures included vertebral wedge angle (VWA), and anterior vertebral height (AVH). ResultsA sum of 69 patients (34 patients in Group A and 35 patients in Group B) were enrolled in the study. The patients in both the groups showed similar outcomes with regards to age, gender, fracture type and site. We did not find any statistically difference between the two groups in corrected rate of VWA or AVH (P > 0.05). In terms of clinical variants such as VAS and ODI scores, there were also no significant differences. However, the SSPF had advantages over PSFFV method in operative time, blood loss, postoperative drainage and postoperative hospitalization time (P > 0.05). There were no serious complications occurring during our study, such as infection, blood vessel injury, spinal cord or nerve root injury. No patient needed revision for loss of correction or failure of instrumentation. ConclusionsSSPF alone is a safe and effective surgical method for restoration and maintenance of vertebral column stability in treating mild TBFs. It gives excellent clinical and radiological results regardless of whether the fractured vertebra is included in the fixation or not.

Minimally Invasive Spine Osteosynthesis (MISO) Technique for Fractures Spine: A Case Series 14 Cases

Background: The choice of treatment of dorso-lumbar spinal fractures in the absence of neurological deficit depends on the classification and severity of injury. In the conventional open approach with posterior pedicle screw fixation, detachment of the Para spinal muscles may be required. In addition, this open approach may be disadvantaged by prolonged operative time, increased intraoperative bleeding and delayed functional rehabilitation. All these problems appear to encourage orthopedic surgeons to limit secondary iatrogenic insult in these patients by mini open surgery. The goal of this study is to evaluate the effectiveness of minimally invasive treatment of dorsolumbar fractures by mini open surgical pedicle screw fixation and to discuss the potential benefits and drawbacks of this procedure. Patients and methods: This is a prospective study involves 14 Patients (10 males) treated and followed between Feb. 2010 to Feb 2014. All had acute traumatic single level dorso-lumbar spine fractures, age range 17-47 years (mean 30.1 ± 7.9 yrs). Patients with pathological fractures, neurological injury, anatomical variations of the cord or vertebrae, mental illness, significant surgical contraindications, osteoporosis, refusing to sign informed consent and those with (TLICS) score ≤4 or load sharing score ≥7 were excluded from the study. All the cases had been treated by minimal invasive posterior approach. Total of 56 screws and 28 rods were applied utilizing the conventional posterior instrumentation. Results: Mean post-operative hospital stay 3.8 days. No major complications as spinal cord, nerve root or blood vessel injuries occurred. No screws were broken and just two screws were malpositioned. All patients improved clinically, and the outcome (according to modified MacNab criteria) was considered excellent in six patients, good in seven, and poor in one patient. Conclusion: Mini open surgery for posterior pedicle screws fixation has attracting increasing attention as it brings a multitude of advantages including: less bleeding, lower incidence of postoperative intractable low back pain and reduced hospitalization stay. However; some shortcomings as limited indications, unsuitability for long segment fusion and high load-sharing score patients restricts its worldwide prevalence.

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.

BackgroundThe development of pedicle screw-based posterior spinal instrumentation is recognized as one of the major surgical treatment methods for thoracolumbar burst fractures. However, the appropriate level in posterior segment instrumentation is still a point of debate. To assesses the long-term results of two-level and three-level posterior fixations of thoracolumbar burst fractures that have load-sharing scores of 7 and 8 points.MethodsFrom January 1998 to May 2009, we retrospectively analyzed clinical and radiologic outcomes of 45 patients with thoracolumbar burst fractures of 7 and 8 points in load-sharing classification who were operated on using two-level posterior fixation (one segment above and one segment below: 28 patients, group I) or three-level posterior fixation (two segments above and one segment below: 17 patients, group II). Clinical results included the grade of the fracture using the Frankel classification, and the visual analog score was used to evaluate pain before surgery, immediately after surgery, and during follow-up period. We also evaluated pain and work status at the final follow-up using the Denis pain scale.ResultsIn all cases, non-union or loosening of implants was not observed. There were two screw breakages in two-level posterior fixation group, but bony union was obtained at the final follow-up. There were no significant differences in loss of anterior vertebral body height, correction loss, or change in adjacent discs. Also, in clinical evaluation, there was no significant difference in the neurological deficit of any patient during the follow-up period.ConclusionsIn our study, two-level posterior fixation could be used successfully in selected cases of thoracolumbar burst fractures of 7 and 8 points in the load-sharing classification.

Anterior D-rod and titanium mesh fixation for acute mid-lumbar burst fracture with incomplete neurologic deficits: A prospective study of 56 consecutive patients.

Background:Anterior decompression and reconstruction have gained wide acceptance as viable alternatives for unstable mid-lumbar burst fracture, but there are no mid and long term prospective studies regarding clinical and radiologic results of mid-lumbar burst fractures.Materials and Methods:An Institutional Review Board-approved prospective study of 56 consecutive patients of mid-lumbar burst fractures with a load-sharing score of 7 or more treated with anterior plating was carried out. All patients were evaluated for radiologic and clinical outcomes. The fusion status, spinal canal compromise, segmental kyphotic angle (SKA), vertebral body height loss (VBHL), and adjacent segment degeneration was examined for radiologic outcome, whereas the American Spinal Injury Association scale, the visual analog scale (VAS), and the employment status were used for clinical evaluation.Results:The patients underwent clinical and radiologic followup for at least 5 years after the surgery. At the last followup, there was no case of internal fixation failure, adjacent segment degeneration, and other complications. Interbody fusion was achieved in all cases. The average fusion time was 4.5 months. No patient suffered neurological deterioration and the average neurologic recovery was 1.3 grades on final observation. Based on VAS pain scores, canal compromise, percentage of VBHL and SKA, the difference was statistically significant between the preoperative period and postoperative or final followup (P < 0.05). Results at postoperative and final followup were better than the preoperative period. However, the difference was not significant between postoperative and final followup (P > 0.05). Thirty-four patients who were employed before the injury returned to work after the operation, 15 had changed to less strenuous work.Conclusion:Good mid term clinicoradiological results of anterior decompression with D-rod and titanium mesh fixation for suitable patients with mid-lumbar burst fractures with incomplete neurologic deficits can be achieved. The incident rate of complications was low. D-rod is a reliable implant and has some potential advantages in L4 vertebral fractures.

The Outcomes of Short and Long Segment Posterior Instrumentation of Thoracolumbar Burst Fractures with a Load Sharing Score of 7 or More

Study Design: Retrospective. Objectives: To investigate outcomes between short and long segment posterior instrumentation of thoracolumbar burst fractures with a load sharing score of 7 or more. Summary of Literature Review: Short segment instrumentation has been recommended in thoracolumbar burst fractures with a load sharing score of 6 or less, and long segment instrumentation has been recommended for those with a score of 7 or more. However, this standard is controversial. Materials and Methods: From March 2006 to January 2014, 45 patients with thoracolumbar fractures with a load sharing score of 7 or more were treated with posterior instrumentation. They were divided into two groups: short (group S) and long segment (group L) groups. Radiologic results were evaluated on the basis of the kyphotic angle and anterior column height. Complications were also reviewed. Results: Groups S and L consisted of 13 and 32 patients and had mean ages of 48.3 and 47.3 years, respectively. In group S, the anterior column height increased from 56.62% to 76.23% postoperatively, and remained at 71.15% at follow-up. The kyphotic angle decreased from 16.27° to 7.55° postoperatively, and was 13.17° at follow-up. In group L, the anterior column height recovered from 49.67% to 70.52% postoperatively, and was 63.73% at follow-up. The kyphotic angle decreased from 20.08° to 6.80° postoperatively, and was 14.18° at follow-up. The changes in the anterior column height and kyphotic angle were not significantly different between groups S and L. Seven cases had complications and the number of cases with complications was not significantly different between groups S and L. Conclusions: Short and long segment instrumentation of thoracolumbar fractures with a load sharing score of 7 or more did not achieve significantly different results.

Surgical Outcome in Thoracolumbar Fractures Managed by Short-segment Pedicle Instrumentation

This study aims to evaluate the efficiency of short-segment instrumentation in treating thoracolumbar fractures in our institute. Twenty-two patients underwent posterior short-segment instrumentation for thoracolumbar fractures in our institute from 2007 to 2010 were included in this retrospective study. Radiological evaluations were carried out by measuring regional kyphosis angle (RA), anterior vertebral body compression percentage (AVC), and sagittal index (SI) during preoperative, postoperative and final follow-up, with the aim to investigate the rate of correction loss and implantation failure in relation to the Arbeitsgemeinschaft für Osteosythese(AO) classification of fracture system and the Load Sharing score system. CT scans were also used to determine the preoperative to postoperative canal compromise ratio. During the final follow-up, clinical outcomes were analysed based on scores from the Denis' Pain's and Work scales and neurological function was scored according to the Frankel classification. At the final follow-up (average duration of 15 months), 21 patients (95%) who partially or fully recovered from thoracolumbar fractures were able to resume daily activities with no complaints of pain, or only slight pain. No deterioration in neurological function were recorded. Upon evaluation at each point of time, (preoperative, postoperative and final follow-up), the average RA improved from 21º to 3.5º to 5.6º, average AVC improved from 40.8% to 90.2% to 88.2%, and average SI changed from 19.1º to 3.1º to 4.1º, respectively. Average canal compromise ratio decreased from 45% to 6.7% after surgery. No correlation was found between loss of correction and AO classification of fracture system, and loss of correction and Load Sharing system scores. Also, no correlation was found between clinical outcomes and the correction loss limited to 10º. Posterior short-segment fixation in thoracolumbar fractures showed a satisfactory outcome in 95% of the patients based on a 15-month follow-up in our institute, even among patients with comminuted fractures injuries.

Comparison of Short Segment and Long Segment Posterior Instrumentation of Thoracolumbar and Lumbar Bursting Fractures at Load Sharing Score 7 or Above

Comparison of Short Segment and Long Segment Posterior Instrumentation of Thoracolumbar and Lumbar Bursting Fractures at Load Sharing Score 7 or Above

Does the load-sharing classification predict ligamentous injury, neurological injury, and the need for surgery in patients with thoracolumbar burst fractures?

The load-sharing score (LSS) of vertebral body comminution is predictive of results after short-segment posterior instrumentation of thoracolumbar burst fractures. Some authors have posited that an LSS > 6 is predictive of neurological injury, ligamentous injury, and the need for surgical intervention. However, the authors of the present study hypothesized that the LSS does not predict ligamentous or neurological injury. The prospectively collected spinal cord injury database from a single institution was queried for thoracolumbar burst fractures. Study inclusion criteria were acute (< 24 hours) burst fractures between T-10 and L-2 with preoperative CT and MRI. Flexion-distraction injuries and pathological fractures were excluded. Four experienced spine surgeons determined the LSS and posterior ligamentous complex (PLC) integrity. Neurological status was assessed from a review of the medical records. Forty-four patients were included in the study. There were 4 patients for whom all observers assigned an LSS > 6, recommending operative treatment. Eleven patients had LSSs ≤ 6 across all observers, suggesting that nonoperative treatment would be appropriate. There was moderate interobserver agreement (0.43) for the overall LSS and fair agreement (0.24) for an LSS > 6. Correlations between the LSS and the PLC score averaged 0.18 across all observers (range -0.02 to 0.34, p value range 0.02-0.89). Correlations between the LSS and the American Spinal Injury Association motor score averaged -0.12 across all observers (range -0.25 to -0.03, p value range 0.1-0.87). Correlations describing the relationship between an LSS > 6 and the treating physician's decision to operate averaged 0.17 across all observers (range 0.11-0.24, p value range 0.12-0.47). The LSS does not uniformly correlate with the PLC injury, neurological status, or empirical clinical decision making. The LSSs of only one observer correlated significantly with PLC injury. There were no significant correlations between the LSS as determined by any observer and neurological status or clinical decision making.

Editorial: Load-sharing score

The management of thoracolumbar burst fractures varies considerably among spine surgeons. The loadsharing classification was initially published to predict the success of short-segment posterior fusions for thoracolumbar burst fractures.5 In the following paper, Radcliff et al. studied the relationship between the loadsharing score (LSS) and different aspects of these burst fractures.7 They concluded that the LSS did not correlate with posterior ligamentous complex (PLC) injury, neurological status, or management decision. An interesting finding in this paper is the relatively poor interobserver reliability in determining the LSS. Although the average kappa value for interobserver agreement on the assigned LSS in their report falls within the range of reported results,1,3 the kappa value for an LSS > 6 was relatively low (0.24). When the same injury is given different scores by different observers, it is expected that the assigned score will have a questionable validity and will not correlate with other variables reflecting injury severity or management decisions. Despite acknowledging the issue of interobserver agreement in their report, the authors’ conclusions about the limitations of the LSS are valid. The LSS was only meant to assess the adequacy of anterior column support to allow for a clinical and radiographically successful short-segment posterior fusion. While a higher LSS would be expected to be associated with an increase in PLC injury, this relationship was not established by most of the reviewers. The failure of the LSS to include neurological status is an additional shortcoming. This limitation also occurs in other more comprehensive classification systems.2,4 A classification system for thoracolumbar injuries that would guide management must account for both clinical and radiological variables, and recently such scoring systems have been developed.6,8 One limitation of these systems is the predilection to consolidate heterogeneous injuries into a one-dimensional severity score, and although they may accurately predict which patients will need anterior, posterior, or 360° surgery, the levels requiring treatment in those patients requiring posterior surgery are not addressed. It is in this subset that the LSS has value. If the LSS score is high, then a multilevel instrumented fusion should be considered. The treatment of spinal fractures is complex, requiring a specialist in spinal surgery, and optimal outcomes are achieved when the treating surgeon utilizes all available data. The decision process for the management of thoracolumbar burst fractures must be done on an individual basis in every case after careful consideration of all relevant clinical and radiological variables. Occasionally, even other injuries or the patient’s overall health will influence the process, and it is difficult to make all decisions based on a single scoring or grading system. We congratulate the authors on this well-written paper addressing a timely and important topic. (http://thejns.org/doi/abs/10.3171/2012.1.SPINE111007)

Percutaneous Pedicle Screw Fixation for Neurologic Intact Thoracolumbar Burst Fractures

Prospective consecutive series. To evaluate the efficacy and safety of percutaneous pedicle screw fixation (PPSF) for thoracolumbar AO type A3 fractures with a specially designed surgical instrument system. Minimally invasive surgery including PPSF is becoming increasingly widespread in the spine surgery. The technique of PPSF was mostly used as supplemental fixation combined with minimally invasive posterior or anterior lumbar interbody fusion in management of lumbar degenerative disorders. There are fewer studies available in literature regarding PPSF without additional kyphoplasty or vertebroplasty for management of thoracolumbar burst fractures. Thirty-six adult patients, who had single thoracolumbar AO type A3 fractures and the load-sharing score of 6 or less, underwent application of percutaneous short-segment pedicle screw fixation. Radiologic parameters including kyphotic angle and vertebral height loss were assessed before and after surgery, and functional outcome was evaluated by Prolo questionnaire. All patients were successfully managed with percutaneous minimal invasive procedures. The average operative time was 78 minutes (range 62 to 117 min). The average intraoperative blood loss was 75 mL (range 50 to 220 mL). After a mean follow-up of 48.5 months (range 32 to 63 mo), 31 of 36 (86.1%) patients had a satisfactory result (19 excellent and 12 good) and 5 of them fair. Our clinical results suggest that PPSF can be an alternative for management of thoracolumbar AO type A3 fractures that have no neurologic deficits. With a specially designed percutaneous instrument and pedicle screw system, the procedure has been proved as relatively safe and a minimally invasive approach for the management of thoracolumbar burst fracture without neurologic deficit.

Quantitative selection of indications for combined anteroposterior surgery for thoracolumbar fractures

Objective To discuss the value of thoracolumbar injury classification and severity score (TLICS) and load-sharing scores in guiding selection of the indications of combined anteroposterior surgery for thoracolumbar fractures. Methods A total of 216 patients with thoracolumbar fractures treated surgically from January 2006 to January 2008 were involved in the study. Combined anterior and posterior surgery was carried out in 48 patients including 32 males and 16 females (at average age of 39 years, range 18-55 years). Segments involved T11 in two patients, T12 in eight, L1 in 20 and L2 in 18. According to the classification of Magerl, there were 20 patients with type B1 fractures, 15 with type B2, four with type C1 and nine with type C2. Neurologic status based on ASIA classification was at grade A in five patients, grade B in 16, grade C in 16, grade D in nine and grade E in two. All patients were operated in lateral position at one stage within 14 days after injury, with posterior laminectomy and pedicle fixation, anterior corpectomy, reduction and strut graft. Forty-five patients were followed up for 14-38 months. Plain X-ray radiographs and reconstruction CT were taken to observe the bone healing. Local kyphosis and vertebral canal were also measured. All the patients were evaluated with TLICS and load-sharing scores. Results Lumbar physical lordosis was reconstructed, with no evident correction loss,pseudoarthrosis or implant failure noted during follow-up. The patients treated with combined surgery had TLICS score ≥5 points, load-sharing scores ≥7 points and were combined with posterior ligamentous complex injury, so the fracture could not be sufficiently decompressed and reconstructed with single anterior or posterior surgery. Of all, 45 patients were followed up for 14-38 months (mean 25 months), which showed that all the combined surgeries were performed successfully, with bone fusion and neurological status improved for at least one ASIA grade. No complications like implant breakage, loosening, titanium mesh displacement or subsidence were observed. Conclusions LICS is basically helpful for guiding selection of combined surgery, but does not well evaluate the canal compromise, to which the load-sharing scores can supplement. These two evaluation systems should be applied together. The anteroposterior surgery can be recommended when the patients are with TLICS≥5 points, load-sharing score ≥7 points and combined with ligament complex injury. Key words: Spinal fractures; Thoracic vertebrae; Lumbar vertebrae; Surgical approach

Anterior-Only Stabilization Using Plating With Bone Structural Autograft Versus Titanium Mesh Cages for Two- or Three-Column Thoracolumbar Burst Fractures

A randomized, controlled follow-up study to review patients with acute thoracolumbar burst fractures treated by anterior instrumentation and reconstruction. The objective of this study was to evaluate the results of anterior instrumentation in the treatment of thoracolumbar burst fractures and to determine whether anterior-only approach would be sufficient for highly unstable burst fractures. In this prospective follow-up study, we also compared the results of anterior reconstruction with structural grafting and with titanium mesh cage in a randomized fashion. Anterior decompression and reconstruction supplemented with instrumentation is generally believed to be superior to fixation with posterior pedicle screw instrumentation for a highly unstable burst fracture, but the indications and methods for anterior approach has not been fully documented. A total of 65 patients undergoing anterior plating for a thoracolumbar burst fracture with a load-sharing score of 7 or more between 2000 and 2003 were included this study. They were randomized to receive iliac crest autograft (group A, n = 32) or titanium mesh cages (group B, n = 33). The patients were similar in the distribution of 3-column injuries (n = 8 in group A vs. n = 9 in group B). During the minimum 4-year (range, 4-7 years) follow-up period, all patients were prospectively evaluated for clinical and radiologic outcomes. The Frankel scale, the ASIA motor score, and the Short Form 36 were used for clinical evaluation, whereas the fusion status and the loss of kyphosis correction for the local kyphosis angle were examined for radiologic outcome. All patients in this study achieved solid fusion, with significant neurologic improvement and no significant correction loss as defined by loss of kyphosis correction. The clinical and radiologic results were not significantly different (P > 0.05) at all time points between the 2 groups A and B. Twenty-six of 32 patients in group A still complained of donor site pain to some degree at the final follow-up. No significant impact of 3-column injuries (P > 0.05) were identified on the results for all comparisons. Anterior-only instrumentation and reconstruction with structural autograft or titanium mesh cages is sufficient for surgical treatment of thoracolumbar burst fractures with a load-sharing score of > or = 7 and even with 3-column injuries.