The phenomenon and efficiency of ligamentotaxis after dorsal stabilization of thoracolumbar burst fractures

Surgical timing prevails as the main factor over morphologic characteristics in the reduction by ligamentotaxis of thoracolumbar burst fractures

BACKGROUND

thoracolumbar burst fractures are associated with spinal canal occupation. The indirect decompression of the spinal canal and reduction of the fragment can be achieved with the distraction of the middle column and ligamentotaxis. Nevertheless, the factors that influence the effectiveness of this procedure and its temporality are controversial.

METHODS

The aim of this observational, cross-sectional study was to evaluate the effectiveness of indirect reduction by ligamentotaxis in thoracolumbar burst fractures according to the fracture's radiologic characteristics and the procedure's temporality. Patients diagnosed with a thoracolumbar burst fracture between 2010 and 2021 were submitted to indirect reduction by distraction and ligamentotaxis. A retrospective analysis of radiologic characteristics and temporality of the procedure was performed with an independent sample t-test or Pearson's correlation coefficient, as required.

RESULTS

A total of 58 patients were included in the analysis. Postoperatively, ligamentotaxis significantly improved all radiologic parameters (canal occupation, endplates distance, and vertebra height). Still, none of the radiological characteristics of the fracture (width, height, position, sagittal angle) were associated with the postoperative change in canal occupation. The endplates distance and the temporality of ligamentotaxis significantly predicted the reduction of the fracture.

CONCLUSION

Fragment reduction effectiveness is more significant when performed as early as possible and adequate distraction is achieved using the internal fixator system. The radiologic characteristics of the fractured fragment do not determine its reduction capacity.

In-Fracture Pedicular Screw Placement During Ligamentotaxis Following Traumatic Spine Injuries, a Randomized Clinical Trial on Outcomes

Objective

To investigate the efficacy and safety of two different techniques for spinal ligamentotaxis. Spine ligamentotaxis reduces the number of retropulsed bone fragments in the fractured vertebrae. Two different ligamentotaxis techniques require clinical evaluation.

Methods

This was a randomized clinical trial. The case group was defined as one pedicular screw insertion into a fractured vertebra, and the control group as a no-pedicular screw in the index vertebra. Spine biomechanical values were defined as primary outcomes and complications as secondary outcomes.

Results

A total of 105 patients were enrolled; 23 were excluded for multiple reasons, and the remaining were randomly allocated into the case (n=40) and control (n=42) groups. The patients were followed up and analyzed (n=56). The postoperative mid-sagittal diameter of the vertebral canal (MSD), kyphotic deformity correction, and restoration of the anterior height of the fractured vertebrae showed equal results in both groups. Postoperative retropulsion percentage and pain were significantly lower in the case group than in the control group (p=0.003 and p=0.004, respectively). There were no group preferences for early or long-term postoperative complications.

Conclusions

Regarding clinical and imaging properties, inserting one extra pedicular screw in a fractured vertebra during ligamentotaxis results in better retropulsion reduction and lower postoperative pain.

Percutaneous pedicle screw fixation without arthrodesis of 368 thoracolumbar fractures: long-term clinical and radiological outcomes in a single institution

PURPOSE

Traumatic thoracolumbar (TL) fractures are the most common vertebral fractures. Although a consensus on the preferred treatment is missing, percutaneous pedicle screw fixation (PPSF) has been progressively accepted as treatment option, since it is related to lower soft tissues surgical-injury and perioperative complications rate. This study aims to evaluate the long-term clinical-radiological outcomes after PPSF for TL fractures at a single tertiary academic hospital.

METHODS

This is a retrospective cohort study. Back pain was obtained at preoperative, postoperative and final follow-up using Visual Analog Scale. Patient-reported outcomes, the Oswestry Disability Index and the 36-Item Short Form, were obtained to asses disability during follow-up. Radiological measures included Cobb angle, mid-sagittal index, sagittal index (SI) and vertebral body height loss. A multivariate regression analysis on preoperative radiological features was performed to investigate independent risk factors for implant failure.

RESULTS

A total of 296 patients with 368 TL fractures met inclusion criteria. Mean follow-up was 124.3 months. The clinical and radiological parameters significantly improved from preoperative to last follow-up measurements. The multivariate analysis showed that Cobb angle (OR = 1.3, p < 0.001), SI (OR = 1.5, p < 0.001) and number of fractures (OR = 1.1, p = 0.05), were independent risk factors for implant failure. The overall complication rate was 5.1%, while the reoperation rate for implant failure was 3.4%.

CONCLUSIONS

In our case series, PPSF for TL injuries demonstrated good long-term clinical-radiological outcomes, along with low complication and reoperation rates. Accordingly, PPSF could be considered as a valuable treatment option for neurologically intact patients with TL fractures. Additionally, in this cohort, number of fractures ≥ 2, Cobb angle ≥ 15° and sagittal index ≥ 21° were independent risk factors for implant failure.

The effect of posterior compression of the facet joints for initial stability and sagittal profile in the treatment of thoracolumbar fractures: a biomechanical study

PURPOSE

Surgical treatment of thoracolumbar A3-fractures usually comprises posterior fixation-in neutral position or distraction-potentially followed by subsequent anterior support. We hypothesized that additional posterior compression in circumferential stabilization may increase stability by locking the facets, and better restore the sagittal profile.

METHODS

Burst fractures Type A3 were created in six fresh frozen cadaver spine segments (T12-L2). Testing was performed in a custom-made spinal loading simulator. Loads were applied as pure bending moments of ± 3.75 Nm in all six movement axes. We checked range of motion, neutral zone and Cobb's angle over the injured/treated segment within the following conditions: Intact, fractured, instrumented in neutral alignment, instrumented in distraction, with cage left in posterior distraction, with cage with posterior compression.

RESULTS

We found that both types of instrumentation with cage stabilized the segment compared to the fractured state in all motion planes. For flexion/extension and lateral bending, flexibility was decreased even compared to the intact state, however, not in axial rotation, being the most critical movement axis. Additional posterior compression in the presence of a cage significantly decreased flexibility in axial rotation, thus achieving stability comparable to the intact state even in this movement axis. In addition, posterior compression with cage significantly increased lordosis compared to the distracted state.

CONCLUSION

Among different surgical modifications tested, circumferential fixation with final posterior compression as the last step resulted in superior stability and improved sagittal alignment. Thus, posterior compression as the last step is recommended in these pathologies.

Percutaneous Spine Fusion Combined with Whole-Body Traction in the Acute Surgical Treatment of AO A- and C-Type Fractures: A Technical Note

BACKGROUND

A diminished level of pain following the operation and shortened hospitalization are the distinct advantages of minimally invasive spine surgery (MISS). However, manipulating the spine with additional MISS tools (e.g., distraction and compression devices) is often cumbersome. Our paper draws attention to a cost-free, fast, indirect decompression method that can be used in the acute treatment of thoracolumbar spine fractures. The presented method involves ligamentotaxis by whole-body traction in the operating room combined with percutaneous spine fixation.

METHODS

Fifteen patients with thoracolumbar injuries A type and C type (without distraction) by AO classification were operated sequentially with the combination of whole-body traction and percutaneous minimally invasive spine fixation. Data were analyzed retrospectively.

RESULTS

A total of 139 screws were implanted into 70 segments in 6 female and 9 male patients. The average clinical follow-up was 16 months. Average preoperative traumatic kyphosis was 17 degrees, and an average postoperative kyphosis was 1.8 degrees. The fractured vertebrae's height gain was an average of 11.0 mm (range 3.9-21.9 mm) ventrally and an average of 5.4 mm (range 1-11.2 mm) dorsally after the surgeries. The spinal canal space narrowing showed an average 6.5 mm improvement postoperatively. Operative time averaged 2 hours and 34 minutes, and blood loss averaged 250 mL (range 150-400 mL). No neurologic complications and wound healing problems were observed.

CONCLUSIONS

The combination of MISS and whole-body traction provided successful anatomical correction in thirteen of the fifteen cases of compression type thoracolumbar fractures without extensive surgical exploration.

Analysis and improvement of the three-column spinal theory

Background

Denis and Ferguson et al.’s three-column spinal theory has been widely accepted and applied. However, this three-column theory was proposed based solely on observation and experience without thorough documented data and analysis. The aim of this study was to analyze and improve Denis and Ferguson et al.’s three-column spinal theory to propose a novel three-column concept in epidemiology, morphology and biomechanics.

Methods

A retrospective analysis of the computed tomography imaging data of patients with a diagnosis of T11-L5 vertebral fractures was conducted between February 2010 and December 2018. Three-dimensional (3D) distribution maps of fracture lines of all subjects were obtained based on 3D mapping techniques. In addition, a 25-year-old health male volunteer was recruited for the vertebral finite element force analysis.

Results

The present study enrolled 459 patients (age: 48 ± 11.42 years), containing a total of 521 fractured vertebrae. The fracture lines peaked in the upper and the outer third sections of the vertebra, starting from the anterior part of the vertebral pedicles in 3-D maps. Regarding flexion and extension of the spine, the last third of the vertebral body in front of the spinal canal was one main stress center in the finite element analysis. The stress on the vertebral body was greater in front of the pedicles in the lateral bending.

Conclusion

The study reveals that the posterior one-third of the vertebral body in front of the spinal canal and the posterior one-third of the vertebral body in front of the pedicle are very different in terms of fracture characteristics and risks to spinal canal (3D maps and stress distributing graphs), therefore, they should be classified as different columns. We provide strong evidence that Su’s three-column theory complies with the characteristics of vertebral physiological structure, vertebral fracture, and vertebral biomechanics.

Graphical abstract

Minimally Invasive Pedicle Screw Fixation With Indirect Decompression by Ligamentotaxis in Pathological Fractures

BACKGROUND

The spine is the most common site of bony metastases. Associated pathological fractures can result in pain, neurological deficit, biomechanical instability, and deformity.

OBJECTIVE

To present a minimally invasive technique for indirect decompression by ligamentotaxis in pathological fractures.

METHODS

A minimally invasive approach was utilized to perform percutaneous pedicle screw fixation in patients who required stabilization for pathological fractures. Preoperative and postoperative computed tomography and magnetic resonance imaging were used to compare spinal canal area and midsagittal canal diameter.

RESULTS

Two patients with newly diagnosed pathological fractures underwent minimally invasive treatment. Each presented with minimal epidural disease and a chief complaint of intractable back pain without neurological deficit. They underwent minimally invasive pedicle screw fixation with indirect decompression by ligamentotaxis. In each case, postoperative imaging demonstrated an increase in spinal canal area and midsagittal canal diameter by an independent neuroradiologist. There were no perioperative complications, and each patient was neurologically stable without evidence of hardware failure at their 5- and 6-mo follow-up visits.

CONCLUSION

Minimally invasive percutaneous fixation can be used to stabilize pathological fractures and provide indirect decompression by ligamentotaxis. This procedure is associated with minimal blood loss, low morbidity, and rapid initiation of radiation therapy. Only patients with minimal epidural disease, stenosis caused primarily by bony retropulsion, and mild-to-moderate deformity should be considered candidates for this approach.

Necessity of Direct Decompression for Thoracolumbar Junction Burst Fractures with Neurological Compromise

BACKGROUND

Surgical management of burst fractures is controversial, with many different operative options. From a posterior approach, decompression of the spinal cord can be performed through both indirect and direct methods, the former relying on ligamentotaxis. It is unclear whether indirect decompression with ligamentotaxis is as effective as direct decompression.

METHODS

Prospective, randomized controlled data were retrospectively analyzed to include only burst fractures of the thoracolumbar junction. Patients were treated with either direct decompression, involving wide posterior decompression in addition to operative stabilization, or indirect decompression, where decompression was performed solely through ligamentotaxis. Patients were followed up at 6 months with clinical assessment and imaging. Additional clinical assessment was performed at 1 year. For all analyses, P < 0.05 was significant.

RESULTS

The study included 46 patients, with 18 patients in the direct decompression subgroup and 28 patients in the indirect decompression subgroup. The average age of the full cohort was 35.1 ± 13.1 years (range, 16-60 years). Most patients had L1 fractures (21/46; 46%), with an AOSpine classification type A4 fracture morphology (17/46; 37%), and were American Spinal Injury Association grade B (18/46; 39%). Both treatments resulted in similar increases in canal diameter and decreases in dural sac compromise (P > 0.5) at 6-month follow-up. Both treatments resulted in similar grades of neurological improvement (P = 0.575) at 1 year.

CONCLUSIONS

There were no significant differences in clinical and imaging outcomes when comparing direct decompression with ligamentotaxis. Ligamentotaxis alone may be effective in carefully selected cases.

Minimally Invasive Decompression and Intracorporeal Bone Grafting Combined with Temporary Percutaneous Short-Segment Pedicle Screw Fixation for Treatment of Thoracolumbar Burst Fracture with Neurological Deficits

OBJECTIVE

We evaluated the clinical and radiographic outcomes of patients with thoracolumbar burst fractures and neurological deficits treated with minimally invasive decompression and intracorporeal bone grafting combined with percutaneous short-segment stabilization.

METHODS

Patients with thoracolumbar burst fractures and neurological deficits underwent minimally invasive decompression and intracorporeal bone grafting combined with percutaneous short-segment stabilization. Instrumentation was removed approximately 1 year after vertebral fracture union. The clinical and radiographic outcomes were analyzed.

RESULTS

The mean operative duration and intraoperative bleeding volume were 135 ± 63 minutes and 120 ± 200 mL, respectively. The average American Spinal Injury Association impairment scale scores had significantly improved at the final follow-up examination. The visual analog scale score had decreased from 7.8 ± 1.1 preoperatively to <2.9 ± 1.3 (P < 0.05) at 1 week postoperatively. The Oswestry disability index had decreased from 86.1 ± 8.8 preoperatively to 15.9 ± 6.4 (P < 0.05) at 1 year postoperatively. The canal stenosis index had improved from 43.4% ± 12.0% to 93.8% ± 4.8% (P < 0.05). The sagittal Cobb angle had been corrected from 17.8° ± 7.5° to 4.0° ± 1.9° (P < 0.05) and remained at 4.9° ± 2.0° (P > 0.05) at 1 year postoperatively. The sagittal index had been corrected from 16.6° ± 6.1° to 0.3° ± 4.6° (P < 0.05) and remained at 1.5° + 4.5° (P > 0.05) at 1 year postoperatively. The anterior vertebral height had increased from 49.3% ± 11.1% to 97.6% ± 6.5% (P < 0.05) and remained at 95.7% ± 6.0% (P > 0.05) at 1 year postoperatively. After implant removal, the total kyphosis correction losses were 1.5° ± 0.8° for the Cobb angle, 2.0° ± 1.1° for the sagittal index, and 3.4% ± 2.1% for the anterior vertebral height. One pullout screw and one broken rod were found in 1 patient each.

CONCLUSION

Minimally invasive decompression and intracorporeal bone grafting combined with percutaneous short-segment fixation yielded satisfactory results in decompression and immediate kyphosis correction. Additionally, this procedure resulted in maintenance of the vertebral height and prevented late correction loss after implant removal.

Minimally Invasive Surgery for the Treatment of Traumatic Monosegmental Thoracolumbar Burst Fractures: Clinical and Radiologic Outcomes of 144 Patients With a 6-year Follow-Up Comparing Two Groups With or Without Intermediate Screw

STUDY DESIGN

This was a retrospective study of the clinical and radiologic outcomes of traumatic thoracolumbar (TL) burst fractures.

OBJECTIVES

We aimed to evaluate the clinical and radiologic outcomes after 6 years of follow-up of 144 patients with monosegmental TL burst fractures treated with percutaneous short-segment pedicle screw fixation, comparing two groups with versus without placement of an intermediate screw at the fractured vertebra.

SUMMARY OF BACKGROUND DATA

Traumatic TL fractures are the most common vertebral fractures, especially at the TL junction (T10-L2). Minimally invasive surgery (MIS) is a valuable treatment option for traumatic TL burst fractures.

MATERIALS AND METHODS

The clinical outcomes and radiologic parameters (Cobb angle, midsagittal index, and sagittal index) of 144 patients with traumatic monosegmental TL fractures treated with MIS were evaluated preoperatively, postoperatively, and after 3 and 6 years of follow-up. Patients were categorized into a nonintermediate screw group (nISG) and an intermediate screw group (ISG), and the groups were compared.

RESULTS

There were 71 patients (49.3%) in the nISG and 73 patients (50.7%) in the ISG. The radiologic parameters improved significantly more from the preoperative evaluation to the 6-year follow-up in the ISG than in the nISG (P<0.025). There were no significant differences in the mean Oswestry Disability Index (ODI) and Visual Analog Scale scores at the 6-year follow-up between the ISG and the nISG: 15.6% (ISG) versus 16.8% (nISG) for ODI (P<0.1) and 2.2 (ISG) versus 2.4 (nISG) for Visual Analog Scale score (P<0.85) (P<0.73).

CONCLUSIONS

MIS showed good clinical outcomes 6 years after surgery in both the ISG and the nISG. The additional intermediate screw significantly improved radiologic parameters but not clinical outcomes.

Risk Factor of Failed Reduction of Posterior Ligamentatoxis Reduction Instrumentation in Managing Thoracolumbar Burst Fractures: A Retrospective Study

OBJECTIVE

To determine whether radiographic findings associated with thoracolumbar burst fractures could be predictors of failure of short-segment posterior instrumentation with insertion screw at the fracture level (SSPI-f).

METHODS

Seventy-five patients with thoracolumbar burst fracture surgically treated by SSPI-f were enrolled in the study and divided into 2 groups: a reduction group (n = 46) and a failed-reduction group (n = 29). Radiographic data including local kyphosis, Cobb angle, anterior vertebral height, posterior vertebral height (PVH), anterior/posterior vertebral height ratio, interpedicle distance (IPD), bony compress area, bony fracture area, and compress-fracture area of the fractured vertebra and clinical data including age and neurologic function were also analyzed. t test, Pearson χ² test, and binary logistic regression were performed to compare the values.

RESULTS

The PVH in the failed-reduction group was smaller than that of the reduction group (83.5% ± 7.2% and 89.1% ± 5.4%, respectively) (P = 0.001). The IPD differed between the reduction and failed-reduction group (18.0% ± 4.1% and 25.8% ± 7.1%, respectively) (P < 0.001). There was a statistical difference between the 2 groups in delayed time before surgery (P = 0.008). There was a significant difference of bony fracture area and compress-fracture area of the fractured vertebra between the failed-reduction and reduction group (both P < 0.001). Binary logistic regression showed that IPD was a risk factor of reduction failure of SSPI-f (P = 0.001).

CONCLUSIONS

These results showed that increased IPD was a risk factor of failed-reduction of SSPI-f in managing thoracolumbar burst fractures, particularly for patients with neurologic deficit, whereas local kyphosis, Cobb angle, anterior vertebral height, PVH, anterior/posterior vertebral height ratio, bony compress area, bony fracture area, and compress-fracture area of the fractured vertebra were not.

Posterior Distraction and Instrumentation Cannot Always Reduce Displaced and Rotated Posterosuperior Fracture Fragments in Thoracolumbar Burst Fracture

STUDY DESIGN

A retrospective clinical study.

OBJECTIVE

To determine the imaging features that can be used to predict failure of reduction of a retropulsed fracture fragment by posterior ligamentotaxis in thoracolumbar burst fractures.

SUMMARY OF BACKGROUND DATA

Posterior instrumentation and distraction with ligamentotaxis has been successfully used to shift retropulsed fragments anteriorly in thoracolumbar burst fractures. However, posterior longitudinal ligament rupture can lead to treatment failure. The exact preoperative radiographical parameters associated with failure of reduction remain unknown.

MATERIALS AND METHODS

A total of 85 patients who suffered from thoracolumbar burst fractures with significant retropulsion of fragments into the spinal canal, as confirmed by preoperative computed tomography and followed by postoperative computed tomography, were retrospectively analyzed. Seventy-three patients (85.9%) in whom the fragments were reduced by ligamentotaxis were included in the reduced group. In 12 patients (14.1%), the fracture fragment in the spinal canal was not reduced, and these patients were included in the nonreduced group. Neurologic status was classified according to the scoring system of the American Spinal Injury Association (ASIA). The displaced distance and rotation angle of the fracture fragment were measured at the fractured segment.

RESULTS

Preoperatively,the average displacement distances into the spinal canal of rotated posterosuperior fragments was 0.53 cm in the reduced group and 0.94 cm in the nonreduced group (P=0.002). The average rotation angles of the fracture fragments were 43.2 degrees in the reduced group and 61.7 degrees in the nonreduced group (P=0.012). "Double cortical surfaces" of the fragment were observed in the nonreduced patients. Neurological function was evaluated and recorded at the 2-year follow-up examination. There was no significant difference in the ASIA recovery grade between the 2 groups (P=0.668).

CONCLUSIONS

Displaced and rotated posterosuperior fracture fragments in thoracolumbar burst fracture cannot always be reduced by posterior ligamentotaxis. The 2 criteria for treatment failure that were most consistently present in our series were a displacement distance greater than 0.85 cm and a rotation angle greater than 55 degrees.

Factors affecting postural reduction in posterior surgery for thoracolumbar burst fracture

STUDY DESIGN

Retrospective analysis of a prospectively collected patient database.

OBJECTIVE

To investigate the significance and relevant factors of postural kyphosis reduction during posterior surgical treatment of thoracolumbar burst fracture.

SUMMARY OF BACKGROUND DATA

Optimal reduction of kyphosis is a goal in the surgical treatment of thoracolumbar burst fracture. Several factors are known to limit the amount of posterior surgical reduction. However, few comprehensive assessments of intraoperative postural reduction have been reported.

METHODS

Seventy-two consecutive patients who underwent posterior surgical treatment for thoracolumbar (T11-L2) burst fracture were included. Postural reduction was evaluated using C-arm fluoroscopic images and regarded as insufficient when the lateral Cobb angle was ≥20 degrees or AP Cobb angle ≥10 degrees. Clinical characteristics including sex, age, body mass index, time to operation, injury level, and neurological injury, as well as radiologic characteristics including fracture morphology, fracture deformity, canal stenosis, and ligament injuries were investigated to determine the relevant factors.

RESULTS

The mean lateral Cobb angle was 22.2±11.0 degrees preoperatively, 16.4±7.7 degrees after postural reduction (P<0.001), and 13.4±6.9 degrees after instrumental reduction (P<0.001). Insufficient postural reduction was found in 25 (34.7%) patients, all of which were lateral. The relevant factors for insufficient reduction, as identified by multivariate analysis, were time to operation >72 hours (OR, 6.453; 95% CI, 1.283-32.553), burst-split type injury (OR, 4.689; 95% CI, 1.314-25.225), and anterior compression ratio >0.5 (OR, 2.284; 95% CI, 1.151-19.811).

CONCLUSIONS

Postural reduction plays an important role in the reduction of kyphosis and compression deformity after thoracolumbar burst fracture. However, it was affected by delayed operation time, burst-split type injury, and severe anterior vertebral compression.

Relationship between fracture-relevant parameters of thoracolumbar burst fractures and the reduction of intra-canal fracture fragment

OBJECTIVE

Posterior longitudinal ligament reduction (PLLR) has been widely used for treatment of thoracolumbar burst fractures. However, there are no systemic studies assessing the influence of position parameters of intra-canal fracture fragment (IFF) itself on outcome of reduction. The aim of this study was to analyze the relationship between position parameters of IFF and the reduction efficacy of PLLR.

METHODS

Sixty-two patients (average age, 36.9 years) with single thoracolumbar burst fractures and intact posterior longitudinal ligaments were recruited. Patients were divided into reduced and unreduced groups based on IFF reduction situations by PLLR. Preoperative and intraoperative computed tomography (CT) were used to evaluate reduction and location parameters of IFF, such as position, width, height, inversion, and horizontal angle, ratio of width of IFF to the transverse diameter of vertebral canal (R 1), and ratio of height of IFF to height of injured vertebrae (R 2) before and after PLLR.

RESULTS

There were significant differences in width (P < 0.001), height (P = 0.0141; R 1, P < 0.001), and R 2 (P = 0.0045) between the two groups. When width of IFF was more than 75 % of transverse diameter of vertebral canal and height of IFF was more than 47 % of height of injured vertebrae, the IFF could not be reduced by PLLR.

CONCLUSIONS

In patients with thoracolumbar burst fractures, IFF in apterium of the posterior longitudinal ligament cannot be reduced by PLLR. For thoracolumbar burst fractures that cover the posterior longitudinal ligament, the width and height of IFF are important parameters that influence reduction quality.

Implant removal after percutaneous short segment fixation for thoracolumbar burst fracture : does it preserve motion?

Objective

The purpose of this study was to evaluate the efficacy of implant removal of percutaneous short segment fixation after vertebral fracture consolidation in terms of motion preservation.

Methods

Between May 2007 and January 2011, 44 patients underwent percutaneous short segment screw fixation due to a thoracolumbar burst fracture. Sixteen of these patients, who underwent implant removal 12 months after screw fixation, were enrolled in this study. Motor power was intact in all patients, despite significant vertebral height loss and canal compromise. The patients were divided into two groups by degree of osteoporosis : Group A (n=8), the non-osteoporotic group, and Group B (n=8), the osteoporotic group. Imaging and clinical findings including vertebral height loss, kyphotic angle, range of motion (ROM), and complications were analyzed.

Results

Significant pain relief was achieved in both groups at final follow-up versus preoperative values. In terms of vertebral height loss, both groups showed significant improvement at 12 months after screw fixation and restored vertebral height was maintained to final follow-up in spite of some correction loss. ROM (measured using Cobb's method) in flexion and extension in Group A was 10.5° (19.5/9.0°) at last follow-up, and in Group B was 10.2° (18.8/8.6°) at last follow-up. Both groups showed marked improvement in ROM as compared with the screw fixation state, which was considered motionless.

Conclusion

Removal of percutaneous implants after vertebral fracture consolidation can be an effective treatment to preserve motion regardless of osteoporosis for thoracolumbar burst fractures.

Seat belt syndrome with cauda equina syndrome: two unique cases in the same motor vehicle accident

STUDY DESIGN

Case report.

OBJECTIVE

To describe the surgical technique and outcome of 2 cases of lap-shoulder belt injury involving burst fracture at L5 and cauda equina syndrome (CES).

SUMMARY OF BACKGROUND DATA

Lap-shoulder belts have largely replaced lap belts in the front seats of cars, and therefore the concept of seat belt injury needs re-evaluation.

METHODS

Two adults, the driver and front seat passenger in the same car involved in a collision, sustained lap-shoulder belt injury. One developed L5 Denis type A burst fracture and the other developed L5 Denis type B burst fracture. Both had CES. They were surgically managed by decompression of the spinal canal, which included removal of retropulsed fragments without impacting them. Both patients received short-segment transpedicle screws and rod system instrumentation without the fractured vertebra being included.

RESULTS

The percentage of preoperative degree of canal displacement of the retropulsed fragment was 60% in one patient and 55% in the other based on computed tomography. The mechanism of injury in both patients might be axial loading. After surgical intervention, the CES including lower leg weakness/numbness and bladder/bowel dysfunction clinically improved in both patients.

CONCLUSION

Two adults in the same car involved in a collision were wearing lap-shoulder belts, and 1 had Denis type A burst fracture at L5 and the other had Denis type B burst fracture at L5. Both developed CES after the accident. Both patients had a good clinical outcome after surgical treatment.

Efficiency of ligamentotaxis using PLL for thoracic and lumbar burst fractures in the load-sharing classification

The use of pedicle screws for short-segment implants has been known to be dangerous in patients who score a 7 or higher on McCormack's classification. The efficiency of ligamentotaxis of the posterior longitudinal ligament (PLL) and short-segment implants and fusion in relation to McCormack's classification has not been proven. The purpose of this study was to compare the clinical and radiological results of indirect decompression using PLL ligamentotaxis between patients with a high- (score of 7 or higher) or low-grade (score of 6 or less) fracture. Eighteen patients (19 levels) in the low-grade fracture group were compared with 23 patients (27 levels) in the high-grade fracture group. Clinical outcomes were measured using the Oswestry Disability Index (ODI) and visual analog scale (VAS) scores; radiologic measures were determined using the spinal canal area and mean sagittal diameter; and the complications were evaluated and compared. A significant improvement in each groups was found in the mean pre- and postoperative spinal canal area, mean sagittal diameter, Cobb's angle, and anterior vertebral height compression rate. A significant difference was found between the 2 groups in the mean pre- and postoperative spinal canal area, mean sagittal diameter, and anterior vertebral height compression rate. Moreover, the VAS and ODI scores continued to significantly improve at the last follow-up in each group. No difference was found in the prevalence of complications. Despite a high score, no significant difference was found in the clinical and radiological results and the complications. Therefore, indirect decompression using PLL ligamentotaxis was found to be a useful technique for patients who recieve a high McCormack's classification score.

Short Segment Screw Fixation without Fusion for Unstable Thoracolumbar and Lumbar Burst Fracture : A Prospective Study on Selective Consecutive Patients

Objective

The purpose of this prospective study was to evaluate the efficacy and safety of screw fixation without bone fusion for unstable thoracolumbar and lumbar burst fracture.

Methods

Nine patients younger than 40 years underwent screw fixation without bone fusion, following postural reduction using a soft roll at the involved vertebra, in cases of burst fracture. Their motor power was intact in spite of severe canal compromise. The surgical procedure included postural reduction for 3 days and screw fixations at one level above, one level below and at the fractured level itself. The patients underwent removal of implants 12 months after the initial operation, due to possibility of implant failure. Imaging and clinical findings, including canal encroachment, vertebral height, clinical outcome, and complications were analyzed.

Results

Prior to surgery, the mean pain score (visual analogue scale) was 8.2, which decreased to 2.2 at 12 months after screw fixation. None of the patients complained of worsening of pain during 6 months after implant removal. All patients were graded as having excellent or good outcomes at 6 months after implant removal. The proportion of canal compromise at the fractured level improved from 55% to 35% at 12 months after surgery. The mean preoperative vertebral height loss was 45.3%, which improved to 20.6% at 6 months after implant removal. There were no neurological deficits related to neural injury. The improved vertebral height and canal compromise were maintained at 6 months after implant removal.

Conclusion

Short segment pedicle screw fixation, including fractured level itself, without bone fusion following postural reduction can be an effective and safe operative technique in the management of selected young patients suffering from unstable burst fracture.

The ligamentotactic effect on a herniated disc at the level adjacent to the anterior lumbar interbody fusion : report of two cases

The authors report two cases of spontaneous regression of disc herniation at the level adjacent to the anterior lumbar interbody fusion (ALIF) level. This phenomenon may be due to the increased tension on the posterior longitudinal ligament (PLL) by appropriate restoration of the disc height and lumbar lordosis, which is a mechanism similar to ligamentotaxis applied to the thoracolumbar burst fracture.