Long-segment Instrumentation Research Articles

Validity and reliability of the osteoporotic fracture treatment score (OF score) and outcomes across various treatments in osteoporosis vertebral compression fracture patients

BackgroundOsteoporotic vertebral compression fractures (OVF) are prevalent and substantially impact healthcare systems and patients’ quality of life. The osteoporotic fracture treatment score (OF score), developed by the German Society of Orthopedics and Trauma (DGOU), guides surgical decisions, but its reliability and validity are underexplored. This study assessed the OF score’s inter- and intraobserver reliability, validated its treatment recommendations, and investigated intermediate outcomes of different DGOU-recommended surgical strategies for OVF.MethodsA retrospective cohort study was conducted. Inter- and intraobserver reliability of the OF score and its subcomponents were analyzed using clinical and radiographic data. Validity was assessed by comparing the OF score’s recommended treatments with actual treatments received. Outcomes at the final follow-up were back pain visual analog scale, Oswestry Disability Index, EQ-VAS, EQ-5D-5 L, adjacent fracture incidence, local kyphotic angle, and reoperation rates. Patients with at least 1-year follow-up were included.ResultsA total of 157 patients (84.7% female; mean age 74.2 ± 10.5 years) were evaluated. The most frequent osteoporotic fracture (OF) types were OF4 (49.0%) and OF3 (40.8%). The OF score demonstrated good interobserver reliability (ICC = 0.77, 95% CI: 0.65–0.86) and intraobserver reliability (ICC = 0.83, 95% CI: 0.72–0.90). Kappa values for subcomponents ranged from 0.57 to 0.89. Excluding patients with indeterminate recommendations (OF score = 6), 82.9% received treatments concordant with OF score recommendations. Receiver operating characteristic curve analysis showed an area under the curve of 0.77 (95% CI: 0.67–0.86); an OF score cutoff > 6.5 predicted actual treatment with 87.9% sensitivity and 61.0% specificity. All surgical treatments showed comparable improvements in clinical outcomes. However, patients treated with stand-alone cement augmentation (CA) had less local kyphotic angle correction (P = 0.004) and greater postoperative kyphotic progression (P < 0.001) than those undergoing short-segment (SS-PI) or long-segment instrumentation (LS-PI). No significant differences in adjacent fractures or complications were observed.ConclusionsThe OF score is a reliable and valid system with good discriminative ability for surgical decision-making in OVF patients. CA, SS-PI, and LS-PI are viable options with comparable functional outcomes. However, in OF3 or OF4 fractures, caution is advised due to lesser kyphosis correction and greater kyphotic progression with CA compared to SS-PI or LS-PI, as recommended by the DGOU.

Construct length analysis of type B and C cervical and thoracolumbar fractures.

The purpose of this study is to identify if construct length affects the rate of surgical complications and instrumentation revision following surgical fixation of subaxial and thoracolumbar Type B and C fractures. This study evaluates the effect of ankylosing spondylitis/diffuse idiopathic skeletal hyperostosis (AS/DISH) within this population on outcomes. Retrospective review of 91 cervical and 89 thoracolumbar Type B and C fractures. Groups were divided by construct length for analysis: short-segment (constructs spanning two or less segments adjacent to the fracture) and long-segment (constructs spanning more than two segments adjacent to the vertebral fracture). For cervical fractures, construct length did not impact surgical complications (P = 0.641), surgical hardware revision (P = 0.167), or kyphotic change (P = 0.994). For thoracolumbar fractures, construct length did not impact surgical complications (P = 0.508), surgical hardware revision (P = 0.224), and kyphotic change (P = 0.278). Cervical Type B fractures were nonsignificantly more likely to have worsened kyphosis (P = 0.058) than Type C fractures. Assessing all regions of the spine, a diagnosis of AS/DISH was associated with an increase in kyphosis (P = 0.030) and a diagnosis of osteoporosis was associated with surgical hardware failure (P = 0.006). Patients with short-segment instrumentation have similar surgical outcomes and changes in kyphosis compared to those with long-segment instrumentation. A diagnosis of AS/DISH or osteoporosis was associated with worse surgical outcomes.

Transfacetal and transpedicular anterior decompression with posterior stablilization: Effective way for managing all cases of andersson lesion

Abstract Background: Andersson lesion (AL), also known as aseptic spondylodiscitis, is a pathological condition characterized by a destructive lesion in the vertebral or discovertebral region. The aim of this study was to assess functional, radiological, and neurological outcome of midline posterior surgery with transfacetal/transpedicular decompression and long-segment instrumentation and fusion in all patients with AL. Materials and Methods: A total of 36 consecutive patients with AL with or without neurodeficit were managed with midline posterior approach with long-segment fixation, decompression and anterior vertebral reconstruction added by same midline approach. The demographic data, visual analogue scale (VAS), modified Oswestry Disability Index (mODI), ankylosing spondylitis quality of life (ASQoL), local and global kyphosis angle, Frankel neurological grade, blood loss, duration of surgery, perioperative complications, and fusion rate were compiled and assessed. Results: The mean age of the patients was 52 years (26 males and 10 females). Among the patients, 9 patients had thoracic, 25 patients had thoracolumbar, and 2 patients had lumbar vertebral involvement. All patients in the study achieved fusion at final follow-up period of 24 months. The mean duration of hospital stay, intraoperative blood loss, and surgery duration was 6.17 days, 252 mL, and 130 min, respectively. VAS improved from mean 7.69 ± 0.98 to 1.67 ± 0.72, mODI from mean 70.28 ± 3.55 to 21.14 ± 2.13, ASQoL from mean 14.22 ± 1.59 to 7.17 ± 1.25, local kyphosis from 23.61 ± 1.67 to 18.52 ± 1.05, and global kyphosis from 57.02 ± 0.72 to 36.16 ± 1.23, leading to better sagittal balance. Except two patients all had full neurological recovery. Conclusions: Posterior midline approach with long-segment instrumentation and anterior decompression by transpedicular/transfacetal approach and bone grafting with selective use of cages can give satisfactory results with excellent fusion rates and good functional outcomes.

Comparison of biomechanical effects of polyetheretherketone (PEEK) rods and titanium rods in lumbar long-segment instrumentation: a finite element study.

Polyetheretherketone (PEEK) lumbar fusion rods have been successfully used in short-segment posterior instrumentation to prevent adjacent segment degeneration. However, limited studies have reported their application in lumbar long-segment instrumentation. This study aimed to compare the biomechanical performances of PEEK rods and titanium rods in lumbar long-segment instrumentation using finite element (FE) models, with the expectation of providing clinical guidance. A lumbar FE model (A) and four lumbar fixation FE models (BI, CI, BII, CII) of the L1-S1 vertebral body were developed using CT image segmentation (A: intact model; BI: intact model with L2-S1 PEEK rod internal fixation; CI: intact model with L2-S1 titanium rod internal fixation; BII: intact model with L3-S1 PEEK rod internal fixation; CII: intact model with L3-S1 titanium rod internal fixation). A 150-N preload was applied to the top surface of L1, similar to the intact model. The stresses on the lumbar intervertebral disc, facet joint, pedicle screws, and rods were calculated to evaluate the biomechanical effect of the different fixation procedures in lumbar long-segment instrumented surgery. Under the four physiological motion states, the average stresses on the adjacent segment intervertebral disc and facet joint in all fixation models were greater than those in the intact model. Furthermore, the average stresses on the adjacent segment intervertebral disc and facet joint were greater in models CI and CII than in models BI and BII, respectively. The average stresses on the pedicle screws and rods were decreased in models BI and BII compared with models CI and CII under the four physiological motion states, respectively. The PEEK rod internal fixation system may have better biomechanical properties than the titanium rod internal fixation system in delaying adjacent segment degeneration, improving the lumbar function of postoperative patients, and reducing the risk of screw loosening and breakage in lumbar long-segment instrumentation.

Risk factors for Implant Failure in Thoracolumbar Fractures Treated with Posterior Long-Segment Instrumentation

Risk factors for Implant Failure in Thoracolumbar Fractures Treated with Posterior Long-Segment Instrumentation

Evaluation of the effectiveness of the short-segment thoracolumbar instrumentation

Aims: This prospective study aimed to compare the long-term follow-up findings of patients with short-segment thoracolumbar instrumentation with the long-term follow-up findings results of patients with long-segment thoracolumbar instrumentation. Merthods: Patients who underwent surgery for a thoracolumbar junction spine fracture were included in this study. The patient's age, gender, and neurological impairment, "AOSpine Classification Scale", "Visual Analog Scale (VAS)", "modified Japanese Orthopedic Association (mJOA)" and "Oswestry Disability Index (ODI)" scores, pedicle and/or pars interarticularis fractures, anterior, middle, and posterior height loss of the fractured vertebral body (mm), the height loss rate of the fractured vertebra, angulation degree, sagittal and axial spinal canal diameters (mm) and presence of bone fragment extending into the spinal canal on CT images were recorded at admission to the hospital, and the end of the sixth month after surgical intervention. Duration of anesthesia and surgery time, the amount of bleeding during the surgery, the radiation level (mGy) released by fluoroscopy, performing laminectomy, length of stay in the intensive care unit, and hospital were recorded. Additionally, the stability and integrity of the instrumentation were examined with dynamic X-ray images. Results: Preoperative fractured vertebra collapse rates (t=4.175, p=0.001) and surgery times (t=4.175, p=0.001) were different between groups In the long-segment group, preoperative VAS scores (Z=-2.687, p=0.007), mJOA scores (Z=-2.585, p=0.010), and ODI scores (t=53.253, p&lt;0.001) were different from postoperative long-term follow-up values. In addition, in the short segment group, preoperative VAS scores (Z=-2.214, p=0.027), mJOA scores (Z=-2.333, p=0.020), and ODI scores (t=48.338, p&lt;0.001) were different from the postoperative long-term follow-up values. ROC-curve analysis and Logistic Regression analysis results revealed that any study parameter could not predict the decision-making for inserting screws into the fractured vertebra, the need for laminectomy, the risk of developing postoperative instability, or the worse prognosis risk of mJOA. Conclusion: This study's results showed that short-segment instrumentation, which is performed by inserting a screw into the fractured vertebra, is as effective as long-segment instrumentation in providing both clinical and radiological improvement in patients. At the same time, it has advantages such as less operating time, less surgical bleeding, and short anesthesia time. However, it was determined that no parameter of the study could predict the placement of screws in the fractured spine, the need for laminectomy, the risk of postoperative instability, or the prognosis risk of mJOA. Therefore, it was concluded that conducting this study on a larger patient population would be appropriate.

Association between the upper instrumented vertebra screw angles and proximal junctional complications in patients with de novo degenerative lumbar scoliosis.

The aim of this study was to investigate the impact of upper instrumented vertebra (UIV) screw angles on proximal junctional complications in patients with de novo degenerative lumbar scoliosis (DNDLS). A total of 120 patients with DNDLS who underwent posterior long-segment instrumentation and fusion were included. Patients were divided into a proximal junctional kyphosis/failure (PJK/PJF) group and a non-PJK/PJF group. Radiographic parameters were measured, including UIV screw angle, UIV slope, UIV screw slope, fixed segmental angle (FSA), and spinopelvic parameters. Clinical and radiographic data were compared between the two groups. Multivariate logistic regression was used to analyze the independent risk factors of PJK/PJF. Receiver operating characteristic (ROC) curve analysis was used to determine the threshold value to predict PJK/PJF. Thirty-six patients (30.0%) developed PJK or PJF during follow-up. Patients in the PJK/PJF group had a larger postoperative UIV screw angle, a larger postoperative UIV screw slope, and a larger postoperative PJA. A significant increase was observed in UIV screw angle from immediately postoperative assessment to the final follow-up in two groups (p < 0.001). Multivariate logistic analysis indicated that a larger positive postoperative UIV screw angle was an independent risk factor for PJK/PJF (OR 1.546, 95% CI 1.274-1.877). ROC curve analysis indicated that a UIV screw angle ≥ 1° is more likely to develop PJK/PJF. Compared with group A patients (UIV screw angle < 1°), group B patients (UIV screw angle ≥ 1°) had a higher incidence of PJK, PJF, UIV screw loosening, and worse functional scores at the final follow-up. Avoiding insertion of cranially directed UIV pedicle screws may help prevent the development of PJK and PJF in patients with DNDLS.

Pedicle screw augmentation in posterior constructs of the thoracolumbar spine: How many pedicle screws should be augmented?

BackgroundsTo evaluate the effects of different pedicle screw augmentation strategies on screw loosening and adjacent segment collapse at the proximal end of long-segment instrumentation. MethodsEighteen osteoporotic (9 male, 9 female donors; mean age: 74.7 ± 10.9 [SD] years) thoracolumbar multi-segmental motion segments (Th11 – L1) were assigned as follows: control, one-level augmented screws (marginally), and two-level augmented screws (fully augmented) groups (3 × 6). Pedicle screw placement was performed in Th12 and L1. Cyclic loading in flexion started with 100–500 N (4 Hz) and was increased by 5 N every 500 cycles. Standardized lateral fluoroscopy images with 7.5 Nm loading were obtained periodically during loading. The global alignment angle was measured to evaluate the overall alignment and proximal junctional kyphosis. The intra-instrumental angle was used to evaluate screw fixation. FindingsConsidering screw fixation as a failure criterion, the failure loads of the control (683 N), and marginally (858 N) and fully augmented (1050 N) constructs were significantly different (ANOVA p = 0.032).Taking the overall specimen alignment as failure criteria, failure loads of the three groups (control 933 ± 271.4 N, marginally 858 N ± 196 N, and full 933 ± 246.3 N were in the same range and did not show any significance (p = 0.825). InterpretationGlobal failure loads were comparable among the three groups and unchanged with augmentation because the adjacent segment and not the instrumentation failed first. Augmentation of all screws showed significant improved in screw anchorage.

Adding sacral anchors through an S1 alar screw and multirod construct as a strategy for lumbosacral junction augmentation: an in vitro comparison to S1 pedicle screws alone with sacroiliac fixation.

Achieving solid fusion of the lumbosacral junction continues to be a challenge in long-segment instrumentation to the sacrum. The purpose of this study was to test the condition of adding sacral anchors through an S1 alar screw (S1AS) and multirod construct relative to using S1 pedicle screws (S1PSs) alone with sacroiliac fixation in lumbosacral junction augmentation. Seven fresh-frozen human lumbar-pelvic spine cadaveric specimens were tested under nondestructive moments (7.5 Nm). The ranges of motion (ROMs) in extension, flexion, left and right lateral bending (LB), and axial rotation (AR) of instrumented segments (L3-S1); the lumbosacral region (L5-S1); and the adjacent segment (L2-3) were measured, and the axial construct stiffness (ACS) was recorded. The testing conditions were 1) intact; 2) bilateral pedicle screw (BPS) fixation at L3-S1 (S1PS alone); 3) BPS and unilateral S2 alar iliac screw (U-S2AIS) fixation; 4) BPS and unilateral S1AS (U-S1AS) fixation; 5) BPS and bilateral S2AIS (B-S2AIS) fixation; and 6) BPS and bilateral S1AS (B-S1AS) fixation. Accessory rods were used in testing conditions 3-6. In all directions, the ROMs of L5-S1 and L3-S1 were significantly reduced in B-S1AS and B-S2AIS conditions, compared with intact and S1PS alone. There was no significant difference in reduction of the ROMs of L5-S1 between B-S1ASs and B-S2AISs. Greater decreased ROMs of L3-S1 in extension and AR were detected with B-S2AISs than with B-S1ASs. Both B-S1ASs and B-S2AISs significantly increased the ACS compared with S1PSs alone. The ACS of B-S2AISs was significantly greater than that of B-S1ASs, but with greater increased ROMs of L2-3 in extension. Adding sacral anchors through S1ASs and a multirod construct was as effective as sacropelvic fixation in lumbosacral junction augmentation. The ACS was less than the sacropelvic fixation but with lower ROMs of the adjacent segment. The biomechanical effects of using S1ASs in the control of long-instrumented segments were moderate (better than S1PSs alone but worse than sacropelvic fixation). This strategy is appropriate for patients requiring advanced lumbosacral fixation, and the risk of sacroiliac joint violation can be avoided.

Predictive Markers in Decision-Making for Screwing the Fractured Thoracolumbar Vertebra in the Short-Segment Instrumentation.

In this study, it is aimed to compare the long-term results of patients with short-segment instrumentation where screws were inserted into the fractured vertebra with those of patients with long-segment instrumentation applied by skipping the fractured vertebra and reveal the predictive markers in decision-making for screwing fractured vertebra. Patients were separated into two groups, namely, Group A (patients in which the fractured vertebra and vertebrae above and below the fractured vertebra were screwed (short-segment instrumentation, n=22) and Group B (patients in whom the fractured vertebra was not screwed, whereas two vertebrae above and below the fractured vertebra were screwed (long-segment instrumentation, n=27). The presence of pedicle fracture, AOSpine Classification Scale score, the height of the fractured vertebra, vertebra height below the fractured vertebra, spinal canal diameter, and duration of stay in hospital were different between the groups, preoperatively (p<0.05). Fractured vertebra height, vertebra height below the fractured vertebra, and Karnofsky Performance Scale score were different between the groups in long-term follow-up (p<0.05). The preoperative measurement values were similar to each group's postoperative long-term follow-up results. Logistic regression analysis revealed that the presence of pedicle fracture, AOSpine Classification Scale score, vertebra height below the fractured vertebra, and spinal canal diameter could be the best parameters in decision-making for screwing fractured vertebra (p<0.05). Both instrumentation procedures were observed to have similar effectiveness in preventing a collapse in fractured vertebra during long-term follow-up. It was thought that the AOSpine Classification Scale score, presence of pedicle fracture, vertebra height below the fractured vertebra, and spinal canal diameter could be used as predictive markers in decision-making for screwing fractured vertebrae. Consequently, it was concluded that patients with pedicle fractures, more height loss in the vertebra below the fractured vertebra, and narrow spinal canal would not be suitable for screwing the fractured vertebra.

Workflow and performance of intraoperative CT, cone-beam CT, and robotic cone-beam CT for spinal navigation in 503 consecutive patients.

A direct comparison of intraoperative CT (iCT), cone-beam CT (CBCT), and robotic cone-beam CT (rCBCT) has been necessary to identify the ideal imaging solution for each individual user's need. Herein, the authors sought to analyze workflow, handling, and performance of iCT, CBCT, and rCBCT imaging for navigated pedicle screw instrumentation across the entire spine performed within the same surgical environment by the same group of surgeons. Between 2014 and 2018, 503 consecutive patients received 2673 navigated pedicle screws using iCT (n = 1219), CBCT (n = 646), or rCBCT (n = 808) imaging during the first 24 months after the acquisition of each modality. Clinical and demographic data, workflow, handling, and screw assessment and accuracy were analyzed. Intraoperative CT showed image quality and workflow advantages for cervicothoracic cases, obese patients, and long-segment instrumentation, whereas CBCT and rCBCT offered independent handling, around-the-clock availability, and the option of performing 2D fluoroscopy. All modalities permitted reliable intraoperative screw assessment. Navigated screw revision was possible with each modality and yielded final accuracy rates > 92% in all groups (iCT 96.2% vs CBCT 92.3%, p < 0.001) without a difference in the accuracy of cervical pedicle screw placement or the rate of secondary screw revision surgeries. Continuous training and an individual setup of iCT, CBCT, and rCBCT has been shown to permit safe and precise navigated posterior instrumentation across the entire spine with reliable screw assessment and the option of immediate revision. The perceived higher image quality and larger scan area of iCT should be weighed against the around-the-clock availability of CBCT and rCBCT technology with the option of single-handed robotic image acquisition.

Factors and predictive model associated with perioperative complications after long fusion in the treatment of adult non-degenerative scoliosis

IntroductionAdult non-degenerative scoliosis accounts for 90% of spinal deformities in young adults. However, perioperative complications and related risk factors of long posterior instrumentation and fusion for the treatment of adult non-degenerative scoliosis have not been adequately studied.MethodsWe evaluated clinical and radiographical results from 146 patients with adult non-degenerative scoliosis who underwent long posterior instrumentation and fusion. Preoperative clinical data, intraoperative variables, and perioperative radiographic parameters were collected to analyze the risk factors for perioperative complications. Potential and independent risk factors for perioperative complications were evaluated by univariate analysis and logistic regression analysis.ResultsOne hundred forty-six adult non-degenerative scoliosis patients were included in our study. There were 23 perioperative complications for 21 (14.4%) patients, eight of which were cardiopulmonary complications, two of which were infection, six of which were neurological complications, three of which were gastrointestinal complications, and four of which were incision-related complication. The independent risk factors for development of total perioperative complications included change in Cobb angle (odds ratio [OR] = 1.085, 95% CI = 1.035 ~ 1.137, P = 0.001) and spinal osteotomy (OR = 3.565, 95% CI = 1.039 ~ 12.236, P = 0.043). The independent risk factor for minor perioperative complications is change in Cobb angle (OR = 1.092, 95% CI = 1.023 ~ 1.165, P = 0.008). The independent risk factors for major perioperative complications are spinal osteotomy (OR = 4.475, 95% CI = 1.960 ~ 20.861, P = 0.036) and change in Cobb angle (OR = 1.106, 95% CI = 1.035 ~ 1.182, P = 0.003).ConclusionsOur study indicate that change in Cobb angle and spinal osteotomy are independent risk factors for total perioperative complications after long-segment posterior instrumentation and fusion in adult non-degenerative scoliosis patients. Change in Cobb angle is an independent risk factor for minor perioperative complications. Change in Cobb angle and spinal osteotomy are independent risk factors for major perioperative complications.

Short-segment cement-augmented fixation in open separation surgery of metastatic epidural spinal cord compression: initial experience.

High-grade metastatic epidural spinal cord compression from radioresistant tumor histologies is often treated with separation surgery and adjuvant stereotactic body radiation therapy. Historically, long-segment fixation is performed during separation surgery with posterior transpedicular fixation of a minimum of 2 spinal levels superior and inferior to the decompression. Previous experience with minimal access surgery techniques and percutaneous stabilization have highlighted reduced morbidity as an advantage to the use of shorter fixation constructs. Cement augmentation of pedicle screws is an attractive option for enhanced stabilization while performing shorter fixation. Herein, the authors describe their initial experience of open separation surgery using short-segment cement-augmented pedicle screw fixation for spinal reconstruction. The authors performed a retrospective chart review of patients undergoing open (i.e., nonpercutaneous, minimal access surgery) separation surgery for high-grade epidural spinal cord compression using cement-augmented pedicle screws at single levels adjacent to the decompression level(s). Patient demographics, treatment data, operative complications, and short-term radiographic outcomes were evaluated. Overall, 44 patients met inclusion criteria with radiographic follow-up at a mean of 8.5 months. Involved levels included 19 thoracic, 5 thoracolumbar, and 20 lumbar. Cement augmentation through fenestrated pedicle screws was performed in 30 patients, and a vertebroplasty-type approach was used in the remaining 14 patients to augment screw purchase. One (2%) patient required an operative revision for a hardware complication. Three (7%) nonoperative radiographic hardware complications occurred, including 1 pathologic fracture at the index level causing progressive kyphosis and 2 incidences of haloing around a single screw. There were 2 wound complications that were managed conservatively without operative intervention. No cement-related complications occurred. Open posterolateral decompression utilizing short-segment cement-augmented pedicle screws is a viable alternative to long-segment instrumentation for reconstruction following separation surgery for metastatic spine tumors. Studies with longer follow-up are needed to determine the rates of delayed complications and the durability of these outcomes.

Practice Patterns of Spine Surgeons Regarding Osteoporosis: An International Survey.

Osteoporosis (OP) represents a great challenge for the spine surgeon. Despite having effective pharmacological treatments for OP and surgical technical innovations, the awareness of spine surgeons regarding OP seems low. The purpose of this research was to assess practice patterns on the diagnosis and treatment of spine surgeons regarding OP. An electronic survey of ten multiple-choice questions was administered to members of the European Association of Neurosurgical Societies (EANS). The survey asked about the specialty, the workplace, and practice patterns and attitudes regarding OP and spine fusion surgery, pseudoarthrosis, and vertebral compression fractures (VCF). A total of 122 surgeons completed the survey. In patients with suspected OP, 31.4% of surgeons would refer the patient to the OP specialist before surgery and 21.5% chose to perform the surgery without additional studies. A 66.4% of respondents would modify the surgical strategy in the case of OP. The most popular surgical techniques elected were cemented augmented screws (77.9%) and long-segment instrumentation (45.1%). Regarding pseudoarthrosis, 29.5% of surgeons opted to refer to the OP specialist, and 23.8% didn't consider any additional studies Concerning VCF management, 41.32% of respondents would refer the patient for treatment of OP, and the most common therapeutic strategy was conservatively treatment for 4 to 6 weeks and vertebroplasty or kyphoplasty if no improvement (55.74%).There was a higher proportion of surgeons that would not consider preoperative studies or referring patients with suspected OP for spine surgery (χ2 = 4.48, P = .03) and pseudoarthrosis (χ2 = 9.5, P = .002) compared to VCF. There was a greater awareness regarding optimizing OP management in VCF compared to patients with suspected OP for spine arthrodesis or pseudoarthrosis. There still opportunities for improvement for the timely diagnosis and treatment of OP in spine surgery patients.

Short-Segment Instrumentation with Fractured Vertebrae Augmentation by Screws and Bone Substitute for Thoracolumbar Unstable Burst Fractures.

Background For thoracolumbar burst fractures, traditional four-screw (one above and one below) short-segment instrumentation is popular and has a high failure rate. Additional augmentation at the fractured vertebrae is believed to reduce surgical failure. The purpose of this study was to examine the clinical and radiographic results of patients who underwent short-segment posterior instrumentation with augmentation by screws and bone substitutes at the fractured vertebrae and to compare these data to those of patients who underwent long-segment instrumentation for thoracolumbar burst fractures. Methods The study group had twenty patients who underwent short-segment instrumentation with additional augmentation by two screws and bone substitutes at the fractured vertebrae. The control group contained twenty-two patients who underwent eight-screw long instrumentation without vertebra augmentation. Local kyphosis and the anterior body height of the fractured vertebrae were measured. The severity of the fractured vertebrae was evaluated with the load sharing classification (LSC). Any implant failure or loss of correction >10° at the final follow-up was defined as surgical failure. Results Both groups had similar distributions in terms of age, sex, the injured level, and the mechanism of injury before operation. During the operation, the study group had significantly less blood loss (136.0 vs. 363.6 ml, p=0.001) and required shorter operating times (146.8 vs. 157.5 minutes, p=0.112) than the control group. Immediately after surgery, the study group had better correction of the local kyphosis angle (13.4° vs. 11.9°, p=0.212) and restoration of the anterior height (34.7% vs. 31.0%, p=0.326) than the control group. At the final follow-up, no patients in the study group and only one patient in the control group experienced surgical failure. Conclusions Patients with thoracolumbar burst fractures who received six-screw short-segment posterior fixators with augmentation at the level of the fractured vertebrae via injectable artificial bone substitute achieved satisfactory clinical and radiographic results, and this method could replace long-segment instrumentation methods used in unstable thoracolumbar burst fractures.

Comparison of Four Different Posterior Screw Fixation Techniques for the Treatment of Thoracolumbar Junction Fractures

The purpose of this study was to compare clinical and radiologic outcomes of patients who underwent short-segment posterior instrumentation with screw augmentation at the fracture level and long-segment instrumentation for thoracolumbar junction fractures. Sixty-three patients were retrospectively evaluated by being divided into the following 4 groups: Groups A, B, C, and D included patients who had undergone 4-level instrumentation without insertion of screws at the fracture level, 3-level instrumentation by insertion of screws at the fracture level, 4-level instrumentation by insertion of screws at the fracture level, and 5-level instrumentation by insertion of screws at the fracture level, respectively. No significant difference was observed in preoperative local kyphosis angle (LKA) (P > 0.05), whereas there was a significant decrease in early postoperative LKA in Group C compared with the other groups (P < 0.05). However, there was no significant difference of LKA in the 4 groups measured on radiographs obtained at the final follow-up (P > 0.05). Anterior corpus height loss, Cobb angle of the fractured vertebra, and sagittal index, measured pre- and postoperatively and at the final follow-up, showed no significant difference (P > 0.05). There was no statistically significant difference between clinical scores of the 4 groups (P > 0.05). Short-segment posterior instrumentation with screw augmentation at the fracture level provides at least as much mechanical stability as long-segment instrumentation. Moreover, there is no difference between short-segment instrumentation with screw augmentation at the fracture level and long-segment instrumentation in terms of clinical outcomes.

The Influence of Cross-Links on Long-Segment Instrumentation Following Spinal Osteotomy: A Finite Element Analysis

To develop finite element models of spine following osteotomy and evaluate the effect of number and location of cross-links (CLs) on long-segment instrumentation. A finite element model of instrumented spine following osteotomy was created from computed tomography images of a postoperative male patient with thoracolumbar kyphotic deformity. Five fixation models were established to simulate different number and location of CLs. Four loading conditions (flexion, extension, lateral bending, and axial rotation) were applied on the models. Range of motion (ROM), maximum value and distribution of stress on implants, and stress on vertebrae were compared between models. With increased number of CLs, average ROM of instrumented segments was reduced by 2.37%, 1.89%, and 2.49% in flexion, extension, and lateral bending. ROM was reduced by 21.98% in loading axial rotation condition. With increased number of CLs, ROM tended to be limited. Peak stresses were located on rods during axial rotation, on proximal pedicle screws during flexion, and on the osteotomy site during extension and lateral bending. CLs had an effect of dispersing stress concentration. The application of CLs enhanced the rigidity of the construct. With increased number of CLs, ROM of the construct was decreased, especially in axial rotation. CLs can also disperse the stress concentration. After comparing various CL configurations in different motion conditions, we believe that the optimal method is to place 2 CLs at the osteotomy site and the proximal segment.

Clinical and Radiographic Results After Posterior Wedge Osteotomy for Thoracolumbar Kyphosis Secondary to Ankylosing Spondylitis: Comparison of Long and Short Segment

To compare the efficacy of long and short segment instrumentation after pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis caused by ankylosing spondylitis (AS). Sixty-four consecutive AS patients were analyzed and divided into groups according to length of instrumentation. We defined short segment instrumentation (SSI) as construct length <7 levels (≤3 levels above and below the osteotomy) (n= 17). By contrast, long segment instrumentation (LSI) was defined as construct length ≥7 levels (≥4 levels above and ≥3 levels below the osteotomy) (n= 47). Both groups were matched cohorts. Radiographs were analyzed for correction, ossification, and complications. Correction loss in global kyphosis (GK) and lumbar lordosis (LL) of the LSI group was slightly higher than that of SSI group. Notably, a significantly higher modified Stokes Ankylosing Spondylitis Spinal Score (mSASSS) was noted in the SSI group. Pearson correlation analysis demonstrated that thoracic and lumbar spine mSASSS were significantly associated with correction loss in GK and LL, respectively. Two cases of proximal junctional kyphosis and 1 case of rod fracture occurred in the LSI group. Both approaches were able to maintain sustained surgical outcomes. Short segment instrumentation is recommended for AS patients with bridging syndesmophytes. Long constructs are better indicated for patients without fully ossified anterior longitudinal ligaments. Nevertheless, extension of the length of instrumentation might not prevent complications such as proximal junctional kyphosis or rod fracture in patients without fully ossified vertebrae.

Clinical Effects of Posterior Limited Long-Segment Pedicle Instrumentation for the Treatment of Thoracolumbar Fractures

ABSTRACTObjective: The purpose of this study was to assess the clinical effects of treating thoracolumbar fractures with posterior limited long-segment pedicle instrumentation (LLSPI). Methods: A total of 58 thoracolumbar fracture patients were retrospectively analyzed, including 31 cases that were fixed by skipping the fractured vertebra with 6 screws using LLSPI and 27 cases that were fixed by skipping the fractured vertebra with 4 screws using short-segment pedicle instrumentation (SSPI). Surgery time, blood loss, hospital stay, Oswestry disability index (ODI), neurological function, sagittal kyphotic Cobb angle (SKA), percentage of anterior vertebral height (PAVH), instrumentation failure, and the loss of SKA and PAVH were recorded before and after surgery. Results: No significant differences were observed in either the surgery time or hospital stay (P < 0.05), while there were significant differences in blood loss between the two groups. At the final follow-up, both the ODI and the neurological status were notably improved compared to those at the preoperative state (P < 0.05), but the difference between the two groups was relatively small. Furthermore, the SKA and PAVH were notably improved at the final follow-up compared to postoperative values (P < 0.05), but no significant difference was observed between the two groups. During long-term follow-up, the loss of SKA and PAVH in the LLSPI group was significantly less than that in the SSPI group (P < 0.05). Conclusion: Based on strict criteria for data collection and analysis, the clinical effects of LLSPI for the treatment of thoracolumbar fractures were satisfactory, especially for maintaining the height of the fractured vertebra and reducing the loss of SKA and instrumentation failure rates.

Double non-contiguous fractures in a patient with spondylo-epiphyseal dysplasia with spinal ankylosis treated with open and percutaneous spinal fixation technique: a case report

BackgroundPatients with ankylosing spines are susceptible to developing spinal fractures even with minor trauma and can develop early or late neurological injuries. These fractures require early and aggressive surgical management to enable spinal stability and/or neural decompression. Being highly unstable by nature, they require relatively long segment instrumentation and fusion, which can increase paravertebral soft tissue damage and perioperative bleeding. The purpose of this report is to describe a rare case of traumatic double fractures at the cervico-thoracic and thoraco-lumbar transition zones in ankylosing spine with spondylo-epiphyseal dysplasia (SED) of unknown cause, which were successfully treated with a combined open and percutaneous spinal fusion procedure.Case presentationA 46-year-old woman who was diagnosed with non-contiguous fractures in cervico-thoracic and thoraco-lumbar junction zones among multiple injuries sustained in a traffic accident was treated with hybrid techniques for posterior instrumentation with an open approach using a computed tomography (CT)-based navigation system and percutaneous pedicle-screwing method. She regained mobility to pre-admission levels and started walking on crutches 3 months postoperatively. Genetic testing for the cause of SED revealed no mutation in the COL2A1 or TRPVR4 genes. The union of fractured spine was confirmed on CT scan 1 year postoperatively.ConclusionThis is the first report of double spinal fractures in an ankylosing spine with genetically undetermined spondyloepiphyseal dysplasia. A long-segment posterior instrumentation procedure incorporating the invasive treatment of spinal fractures in ankylosing spondylitis or diffuse idiopathic hyperostosis was effective.