Han-Dong Lee

Change in sagittal profiles after decompressive laminectomy in patients with lumbar spinal canal stenosis: a 2-year preliminary report.

Study Design. Retrospective radiological study. Objective. We aimed to determine whether the sagittal profiles of patients with lumbar spinal canal stenosis (LCS) change after decompressive laminectomy. Summary of Background Data. Decompressive laminectomy is the standard technique in the surgical treatment for LCS. Numerous studies have reported favorable clinical outcomes. However, few studies have quantitatively evaluated the radiological outcome of the procedure, including the global balance of the spine and associated pelvic posture. Methods. This study involved 40 consecutive patients with LCS treated with decompressive laminectomy and a control cohort of 40 age- and sex-matched patients with LCS who were treated conservatively. The radiological parameters of the 2 groups including (1) global sagittal balance (C7 plumb line [C7PL], C7/sacrofemoral distance ratio, and spinosacral angle), (2) spinopelvic morphology (pelvic incidence, sacral slope, and pelvic tilt), and (3) spinal parameters (lumbar lordosis and thoracic kyphosis) were measured and compared at baseline, 1-year, and 2-year follow-ups. Results. The demographics and baseline radiological parameters were similar between the 2 groups. The mean C7PL of the laminectomy group was 3.9 ± 2.5 cm at baseline, which decreased significantly to 2.0 ± 1.9 cm at the 1-year follow-up (P = 0.006) and was maintained at this level at the 2-year follow-up (2.3 ± 2.1 cm) (P = 0.013). The mean lumbar lordosis of the laminectomy group was 31.4°± 15.1° at baseline, which increased significantly to 35.6°± 11.7° at the 1-year follow-up (P = 0.021) and was maintained at this level at the 2-year follow-up (35.1°± 14.8°) (P = 0.044). Conclusion. In this study, decompressive laminectomy caused posterior migration of the C7PL and increased the lumbar lordosis. Level of Evidence: 3

Is It Beneficial to Remove the Pedicle Screw Instrument After Successful Posterior Fusion of Thoracolumbar Burst Fractures

Study Design. Case-control study. Objective. To investigate the clinical and radiological outcomes of pedicle screw removal after successful fusion of thoracolumbar burst fractures. Summary of Background Data. Implant removal is a common procedure in orthopedic surgery, although the benefits of and indications for removal remain controversial. Previous studies on pedicle screw removal have reported conflicting outcomes, because the study subjects and surgical goals were heterogeneous in nature. Methods. We studied 45 consecutive patients who underwent implant removal and a control cohort of 45 age- and sex-matched patients who retained their spinal implants after successful posterior fusion of thoracolumbar burst fractures using pedicle screw instrument. In most cases, long-segment instrumentation with short-segment posterior fusion was performed. The mean elapsed period prior to implant removal after index fracture surgery was 18.3 ± 17.6 months. A visual analogue scale for back pain was applied, the Oswestry disability index calculated, and radiological parameters derived at the time of implant removal and 1 and 2 years postoperatively obtained. These data were compared with those of the control group evaluated at the same times after index fracture surgery. Results. Patient demographics, mechanisms of injury, fracture morphologies, and the outcomes of index fracture surgery were similar between the 2 groups. The mean visual analogue scale and Oswestry disability index scores were better at both the 1- and 2-year follow-ups in the implant removal group than in the control group (all P values = 0.000). The segmental motion angle of the implant removal group was 1.6° ± 1.5° at the time of implant removal, and increased significantly to 5.8° ± 3.9° at 1-year follow-up (P = 0.000), and was maintained at this level at the 2-year follow-up (5.9° ± 4.1°) (P = 0.000). Conclusion. In patients treated successfully for thoracolumbar burst fractures, pedicle screw removal is beneficial because it alleviates pain and disability. Restoration of the segmental motion angle after implant removal may contribute to the clinical improvement. Level of Evidence: 3

Trabecular microstructure of the human lunate in Kienböck’s disease

The trabecular microstructure of normal lunates and lunates with Kienböck’s disease was investigated using micro-computed tomography (micro-CT). Five lunates with advanced Kienböck’s disease were obtained during lunate excision and scaphocapitate fusion, and five control lunates were from embalmed cadavers. Microstructural morphometric parameters were measured using micro-CT images. Trabeculations of lunates with Kienböck’s disease were 2.67 times denser and 1.84 times thicker than those of normal lunates. Furthermore, bone surface areas were 1.43 times greater and bone volume 2.67 times greater, and structural model indices were significantly lower in lunates with Kienböck’s disease. The study estimated that high mechanical stress would be applied to lunates with Kienböck’s disease, and suggests that new bone formation and collapse may play important roles in the microstructural changes in the lunate with advanced Kienböck’s disease.

Global Sagittal Imbalance Due to Change in Pelvic Incidence After Traumatic Spinopelvic Dissociation

Objectives: To examine how spinopelvic morphology changes after traumatic spinopelvic dissociation and whether these changes affect the sagittal balance of the spine. Design: Retrospective analysis. Setting: Level I trauma center. Patients: Thirty-nine consecutive patients who were diagnosed with traumatic spinopelvic dissociation and had a minimum 2-year radiological follow-up were included. Intervention: Nineteen patients underwent spinopelvic pedicle screw fixation, 11 patients underwent percutaneous iliosacral screw fixation, and 9 patients were treated conservatively. Main Outcome Measurements: The main outcome measurements are as follows: (1) injury morphology (injury type and kyphotic angulation) at the initial and follow-up visits; (2) sagittal vertical axis (SVA) at the 2-year follow-up; (3) spinopelvic parameters [pelvic incidence (PI), sacral slope, pelvic tilt, lumbar lordosis, and thoracic kyphosis] at the 2-year follow-up; and (4) bodily pain and Oswestry Disability Index at the 2-year follow-up. Results: There were 21 men and 18 women, with a mean age of 28.3 years (15–62 years). At the 2-year follow-up, the mean SVA was 5.4 ± 4.1 cm and the mean PI was 76.9 ± 24.6 degrees. Factors related to SVA after traumatic spinopelvic dissociation were PI (r = 0.441, P = 0.017), pelvic tilt (r = 0.387, P = 0.038), and injury type of complete displacement (r = 0.372, P = 0.047). The bodily pain and Oswestry Disability Index was significantly poorer in patients with SVA modifier “+” than in patients with SVA modifier “0.” Conclusions: Lumbosacral kyphosis after traumatic spinopelvic dissociation increases PI, which can affect the sagittal balance of the spine and clinical outcome. Restoration of lumbosacral orientation is important for preventing sagittal imbalance. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Cost-utility Analysis of Pedicle Screw Removal After Successful Posterior Instrumented Fusion in Thoracolumbar Burst Fractures

Study Design. A cost-utility analysis (CUA). Objective. The aim of this study was to determine the cost-effectiveness of pedicle screw removal after posterior fusion in thoracolumbar burst fractures. Summary of Background Data. Pedicle screw instrumentation is a standard fixation method for unstable thoracolumbar burst fracture. However, removal of the pedicle screw after successful fusion remains controversial because the clinical benefits remain unclear. CUA can help clinicians make appropriate decisions about optimal health care for pedicle screw removal after successful fusion in thoracolumbar burst fractures. Methods. We conducted a single-center, retrospective, longitudinal matched-cohort study of prospectively collected outcomes. In total, 88 consecutive patients who had undergone pedicle screw instrumentation for thoracolumbar burst fracture with successful fusion confirmed by computed tomography (CT) were used in this study. In total, 45 patients wanted to undergo implant removal surgery (R group), and 43 decided not to remove the implant (NR group). A CUA was conducted from the health care perspective. The direct costs of health care were obtained from the medical bill of each patient. Changes in health-related quality of life (HRQoL) scores, validated by Short Form 6D, were used to calculate quality-adjusted life-years (QALYs). Total costs and gained QALY were calculated at 1 year (1 year) and 2 years (2 years) compared with baseline. Results are expressed as an incremental cost-effectiveness ratio (ICER). Different discount rates (0%, 3%, and 5%) were applied to both cost and QALY for sensitivity analysis. Results. Baseline patient variables were similar between the two groups (all P > 0.05). The additional benefits of implant removal (0.201 QALY at 2 years) were achieved with additional costs (

Factors affecting postural reduction in posterior surgery for thoracolumbar burst fracture.

2541 at 2 years), equating to an ICER of

Combination of whole-spine lateral radiograph and lateral scanogram in the assessment of global sagittal balance

12,641/QALY. On the basis of the different discount rates, the robustness of our studys results was also determined. Conclusion. Implant removal after successful fusion in a thoracolumbar burst fracture is cost-effective until postoperative year 2. Level of Evidence: 3

Life-threatening paraspinal muscle hematoma after percutaneous vertebroplasty

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.

Ventral epidural filling technique in interlaminar epidural steroid injection.

BACKGROUND CONTEXT Global balance of human standing is analyzed as the geometric sum of the individual alignments extending from the spinal column to the pelvis, and to the lower limbs. The innovative EOS system has opened new perspectives for the global analysis of whole-body alignment, but its use is very limited because of its high cost. An alternative may be to combine the whole-spine lateral radiograph and the lateral scanogram in the global sagittal analysis of whole-body alignment. PURPOSE We examined to determine the validity and reliability of a lateral scanogram in the measurement of sacropelvic parameters. STUDY DESIGN/SETTING A retrospective radiological study was carried out. PATIENT SAMPLE We randomly selected 100 sets of digital radiographs, both whole-spine radiographs and lower-limb scanograms, from our database. OUTCOME MEASURES Sacropelvic parameters, including pelvic incidence, sacral slope, and pelvic tilt, were measured on both whole-spine radiographs and lower-limb scanograms by three independent examiners on three separate occasions. METHODS Agreement regarding the measurements on both image types was calculated to assess the validity of the lateral scanogram for use in whole-body alignment determinations. Intraobserver and interobserver reliabilities among the types of measurements were calculated. RESULTS The sacropelvic area on the lateral scanogram was not visible in 19 patients (19%). In the remaining 81 patients, the sacropelvic parameters on the lateral scanogram were similar to those on the whole-spine lateral radiograph (Pearson correlation coefficient, 0.764-0.805). Intraobserver and interobserver reproducibilities for both modalities were good to excellent (intraclass correlation coefficient, 0.657-0.984). CONCLUSIONS Sacropelvic parameter measurements on lateral scanogram were reliable and were similar to those measured on whole-spine lateral radiograph. Thus, global alignment can be evaluated using the lateral scanogram in combination with the whole-spine lateral radiograph.

Comparative Analysis of Three Imaging Modalities for Evaluation of Cervical Sagittal Alignment Parameters: A Validity and Reliability Study

Bleeding and hematoma formation is rarely reported in percutaneous vertebroplasty procedure. An 84 year old male presented with a large paraspinal muscle hematoma after a percutaneous vertebroplasty. The patient had neither any prior bleeding disorder nor any anticoagulant treatment. Vital signs of the patient were unstable, and his hemoglobin level decreased daily. After a month of conservative treatment, including transfusion, cryotherapy, pain control and bed rest, his hemoglobin level remained stable and he showed relief from pain. Four months later, hematoma resolved spontaneously and he could walk without back pain.