Tae-Hwan Kim

T1 Slope as a Predictor of Kyphotic Alignment Change After Laminoplasty in Patients With Cervical Myelopathy

Study Design. Prospective study. Objective. To analyze the effect of T1 slope on kyphotic alignment change after cervical laminoplasty in patients with cervical myelopathy. Summary of Background Data. Laminoplasty is a posterior method, and maintenance of both preoperative and postoperative lordotic alignment is prerequisite for the successful surgery. Unfortunately, patients who underwent laminoplasty tend to have kyphotic alignment change after operation despite sufficient preoperative lordosis, and such kyphotic alignment change after cervical laminoplasty can reduce surgical outcome and require additional surgery. Methods. Consecutive patients who underwent cervical laminoplasty for cervical myelopathy were enrolled. Cervical spine lateral radiography in neutral, flexion, and extension were taken before surgery and at 2-year follow-up. Patients were divided into 2 groups according to the preoperative T1 slope, and postoperative cervical alignment change was compared according to the preoperative T1 slope. Results. A total of 51 patients were enrolled in this study. The mean age was 57.2 years (range, 39–88 yr). There were 39 male patients and 12 female patients. There were no differences in age, sex, the presence and type of ossification of posterior longitudinal ligament, and operation level between the patients with higher and lower preoperative T1 slope. Patients with higher preoperative T1 slope had more lordotic preoperative cervical alignment; however, they had more kyphotic alignment changes after laminoplasty (P< 0.001). After univariate logistic regression, only higher preoperative T1 slope was associated with significantly increased odds ratio for postoperative kyphotic alignment changes. Conclusion. We hypothesized that kyphotic alignment change by posterior structural injury after cervical laminoplasty would be more marked in patients with high T1 slope, and demonstrated that patients with cervical myelopathy with high T1 slope had more kyphotic alignment changes after cervical laminoplasty at 2-year follow-up. Level of Evidence: 4

Lumbar Stenosis: A Recent Update by Review of Literature

Degeneration of the intervertebral disc results in initial relative instability, hypermobility, and hypertrophy of the facet joints, particularly at the superior articular process. This finally leads to a reduction of the spinal canal dimensions and compression of the neural elements, which can result in neurogenic intermittent claudication caused by venous congestion and arterial hypertension around nerve roots. Most patients with symptomatic lumbar stenosis had neurogenic intermittent claudication with the risk of a fall. However, although the physical findings and clinical symptoms in lumbar stenosis are not acute, the radiographic findings are comparatively severe. Magnetic resonance imaging is a noninvasive and good method for evaluation of lumbar stenosis. Though there are very few studies pertaining to the natural progression of lumbar spinal stenosis, symptoms of spinal stenosis usually respond favorably to non-operative management. In patients who fail to respond to non-operative management, surgical treatments such as decompression or decompression with spinal fusion are required. Restoration of a normal pelvic tilt after lumbar fusion correlates to a good clinical outcome.

Is It Possible to Evaluate the Parameters of Cervical Sagittal Alignment on Cervical Computed Tomographic Scans

Study Design. Retrospective study. Objective. The purpose of this study was to analyze the relationship of the parameters of cervical sagittal alignment between those obtained from cervical CT and those obtained from radiography, as well as to determine which parameter would help predict physiological lordosis of the cervical spine. Summary of Background Data. Sagittal balance in the cervical spine is as important as the pelvic incidence and is related to the concept of T1 slope. However, many articles including this article based on unclear cervical x-ray radiographs could weakly explain the parameters. To overcome the fundamental limitation of x-ray radiographs, Hallym University Sacred Heart Hospital reported the strong correlation between T1 slope and cervical lordosis on the cervical dimensional CT scans like result by checking by the cervical x-ray radiographs. Methods. A retrospective analysis of data from 50 asymptomatic adults in whom both cervical CT scans and cervical radiograph were obtained at the same time. The T1 slope, Cobb angle C2–C7, neck tilt, and thoracic inlet angle (TIA) obtained from the CT scans and radiographs were assessed. Results. The T1 slope on x-ray was significantly correlated with the T1 slope on CT. The mean of the T1 slope on x-ray was larger than the mean of the T1 slope on CT (3.3° ± 6.1°). More cervical spine lordosis was evident on the cervical radiograph than on the cervical CT scan (5.93° ± 9.0°). No significant difference was seen between the TIA on x-ray and the TIA on CT (TIA on x-ray − TIA on CT, −0.1 ± 7.6, P = 0.959). Conclusion. This difference may be due to the differing effect of gravity upon the spine between the upright versus the supine position. Accordingly, TIA and T1 slope may be used as a guide for the assessment of sagittal balance of the cervical spine. Level of Evidence: N/A

Correlation of magnetic resonance diffusion tensor imaging and clinical findings of cervical myelopathy

BACKGROUND CONTEXTnDespite significant advances in the development of diagnostic technology, the diagnosis of cervical myelopathy (CM) still remains based on the clinical findings, which do not provide the means for a sufficiently accurate diagnosis. Furthermore, conventional magnetic resonance imaging (MRI) using T1- and T2-weighted sequences lacks sensitivity to detect and characterize spinal cord lesions. Considering these uncertainties, several investigators have assessed the diagnostic value of diffusion tensor imaging (DTI), an advanced MRI technique that measures the diffusion of water molecules.nnnPURPOSEnTo determine the diagnostic value of DTI in CM in reliably characterizing spinal lesions and in associating them with the clinical findings.nnnSTUDY DESIGN/SETTINGnProspective cohort study.nnnPATIENT SAMPLEnFifteen CM patients and five healthy volunteers without a history of neurological disorders or of symptoms as controls.nnnOUTCOME MEASURESnSymptoms and signs of CM were evaluated by the use of a modified Japanese Orthopedic Score and the other clinical findings. T2-weighed MRI was used to note the number of compressed levels. Diffusion tensor imaging results were measured according to two parameters, fractional anisotropy (FA) and apparent diffusion coefficient (ADC), at anterior, lateral, and posterior regions of interest (ROIs) in each of five cervical vertebrae, C3-C7.nnnMETHODSnOn diagnosis of CM by clinical evaluation and findings from T2-weighted MRI, the 15 subjects were assigned to two subgroups based on complaints, symptoms, and signs. The nine subjects who had typical CM symptoms such as motor weakness, gait disturbance, clumsiness of the hands, and unilateral hypesthesia were assigned to the paralysis subgroup. The other six subjects, whose main symptom was pain and who had vague signs of upper motor neuron injury despite a definitive finding of CM by T2-weighted MRI, were assigned to the pain subgroup. Once assignments had been made, subjects underwent DTI done by the use of the same scanner as for T2-weighted MRI. Results of DTI for each subgroup and controls were averaged, and the mean was used for comparisons. Diffusion tensor imaging results from the paralysis subgroup were sorted into affected and unaffected sides according to the presence or the absence of symptoms.nnnRESULTSnThe paralysis subgroup and the pain subgroup had similar findings from T2-weighted MRI on presentation. The paralysis subgroup had statistically significantly decreased FA values in the anterior and lateral ROIs on the affected side and in the anterior ROIs on the unaffected side, compared with controls. The paralysis subgroup also had statistically significantly increased ADC values in the anterior ROIs of the affected side, compared with controls. The pain subgroup showed significantly increased ADC values in anterior, lateral, and posterior ROIs.nnnCONCLUSIONSnUse of DTI to quantitatively compare compression in the cervical spinal cords of CM subjects and healthy controls explained individual differences in the clinical findings in the subjects. These findings even applied to CM subjects whose compressed spinal cords looked similar on conventional T2-weighted MRI. Therefore, DTI provided more accurate and reliable information than did conventional T2-weighted MRI about the relationship between spinal cord structure and clinical presentation of CM. Based on our DTI findings, we hypothesized that different clinical findings in CM are attributable to the stage of progression and the severity of pathologic change at presentation. We anticipate that the use of DTI to quantify the extent of myelopathological changes in CM could be more reliable than any other existing diagnostic tools and might provide invaluable information about selecting the optimal treatment for CM and predicting surgical outcomes and prognosis.

Changes in vitamin D status after surgery in female patients with lumbar spinal stenosis and its clinical significance.

Study Design. A prospective cohort study. Objective. To demonstrate the changes in vitamin D status after surgery in female patients with lumbar spinal stenosis (LSS), and its correlation with surgical outcomes. Summary of Background Data. In patients with LSS, general health including walking ability and nutritional status can be markedly improved by decompressive surgery. It can be hypothesized that such improvement may have a positive effect on their vitamin D status. Methods. In total, 31 female patients who underwent decompression and instrumented posterolateral fusion for LSS were enrolled. Serum 25-hydroxyvitamin D (25-OHD) level was measured before the surgery and at 1 year postoperative visit. According to serum 25-OHD level, patients were classified into 3 groups: (1) deficient group, when 25-OHD level was less than 20 ng/mL (< 50 nmol/L); (2) insufficient group, when 25-OHD level was between 20 to 30 ng/mL (50 nmol/L ⩽ 25-OHD < 75 nmol/L); (3) and normal group, when 25-OHD level was 30 ng/mL or more (≥75 nmol/L). The Oswestry Disability Index (ODI) score and health-related quality of life (EQ-5D) were compared according to the level of 25-OHD at 1 year postoperatively. Results. Preoperatively, there were 20 patients in the deficient group, 11 patients in the insufficient group and no patient in the normal group. There were no differences in age, body mass index, preoperative ODI scores, preoperative EQ-5D index scores, and EQ-5D visual analogue scale scores between the 2 groups. Mean preoperative 25-OHD level was 15.8 ng/mL (range, 5.2–29.4 ng/mL) and increased to 19.5 ng/mL (range, 6.3–47.7 ng/mL) 1 year after surgery (P = 0.075). Significant increase of 25-OHD was noted only in the deficient group (P = 0.017). Postoperatively, there were 18 patients in the deficient group, 8 patients in the insufficient group, and 5 patients in the normal group. In the postoperative deficient group, postoperative ODI scores and EQ-5D index scores showed significantly worse outcomes than those in the other groups. The changes in serum 25-OHD level were significantly correlated with the changes in ODI scores (r = −0.580; P = 0.001) and with the changes in EQ-5D index scores (r = 0.379; P = 0.035). In all the groups, postoperative ODI scores (r = −0.665; P < 0.001) and EQ-5D index scores (r = 0.601; P < 0.001) were significantly correlated with postoperative 25-OHD level. Conclusion. Vitamin D deficiency was common in patients with LSS. However, vitamin D status was improved after decompressive surgery, and postoperative 25-OHD level was significantly correlated with surgical outcomes.

Is cervical lordosis relevant in laminoplasty

BACKGROUND CONTEXTnLaminoplasty aims to decompress the spinal cord and stabilize the cervical spine in patients with multilevel cervical lesions. Not every patient with cervical compressive myelopathy is a good candidate for laminoplasty. Most studies recommend that neutral or kyphotic alignments are contraindications for laminoplasty. However, cervical sagittal alignment does not have a strong and consistent effect on the clinical outcomes of laminoplasty. Moreover, many reports on the effect of cervical sagittal alignment did not designate the ideal definition of alignment and used different definitions of lordosis.nnnPURPOSEnTo identify the effect of preoperative cervical alignment according to two different definitions after midline splitting double-door laminoplasty.nnnSTUDY DESIGNnRetrospective cohort study.nnnPATIENT SAMPLEnFrom August 2008 to September 2010, 58 patients were diagnosed with cervical myelopathy and treated with midline splitting double-door laminoplasty.nnnOUTCOME MEASURESnThe clinical results were assessed with the modified Japanese Orthopedic Association (JOA) score, neck disability index (NDI), and visual analog scale (VAS) and were compared to analyze the rate of change between preoperative and postoperative values. Postoperative radiological results at the final follow-up examinations were compared between groups to obtain the change in range of motion and sagittal alignment.nnnMETHODnThe effect of cervical alignment on JOA, NDI, and VAS scales and also on change of alignment and change of range of motion (ROM) at the final follow-up examinations was analyzed statistically between two groups according to two different definitions such as Toyama classification and Cobb angle.nnnRESULTSnNo difference was found between the two groups according to Toyama classification in terms of the postoperative improvement rate of the modified JOA score (p=.086), decreasing rate of the VAS (p=.940) or NDI (p=.211), postoperatively. Additionally, no difference was found for the decreasing rate of ROM (p=.427) or sagittal alignment (p=.864) based on the radiological evaluation results. Also, there was no difference between two groups according to Cobb angle in terms of the modified JOA score (p=.743), VAS (p=.548), or NDI (p=.32), postoperatively. Additionally, no difference was found for the ROM (p=1.000) or sagittal alignment (p=.440) based on the radiological evaluation results.nnnCONCLUSIONSnDespite nonlordosis cervical sagittal alignment, double-door laminoplasty would be effective for patients with cervical myelopathy because of cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament. Furthermore, sagittal alignment is not the absolute and sole factor that surgeons should consider when determining the optimal treatment strategy.

T1 slope and degenerative cervical spondylolisthesis.

Study Design. Retrospective analysis. Objective. The main objectives of this study were to analyze and compare cervical sagittal parameters, including the T1 slope, in a population of 45 patients with degenerative cervical spondylolisthesis (DCS) and to compare these patients with a control group of asymptomatic population. Summary of Background Data. Sagittal balance in the cervical spine is as important as the pelvic incidence and is related to the concept of T1 slope. Compared with degenerative lumbar spondylolisthesis, there are few studies evaluating DCS, and characteristic changes of the cervical sagittal parameters (including T1 slope) in patients with DCS are not well studied. Methods. We identified 45 patients with DCS (5.8%) from a database of 767 patients, using cervical radiograph in a standing position. All had radiograph and computed tomographic scan at the same time. Cervical sagittal parameters were analyzed on computed tomographic scan in a standardized supine position. The following cervical sagittal parameters were measured: T1 slope, neck tilt, thoracic inlet angle, and cervical lordosis (C2–C7 angle). The DCS group was compared with a control group of 45 asymptomatic age- and sex-matched adults to the DCS group, who were studied in a recently published study. Results. Of our initial group of 767 patients, 45 with anterolisthesis (5.8%) were included for this study. The T1 slope was significantly greater for DCS (26.06° ± 7.3°) compared with the control group (22.32° ± 7.0°). No significant difference of the neck tilt, thoracic inlet angle, and C2–C7 angle was seen between the DSC group and the control group. Therefore, the T1 slope of the DSC group was significantly greater than that of the control group (P < 0.005). Conclusion. The DCS group was characterized by a greater T1 slope than the control group; therefore, we suggest that a high T1 slope may be a predisposing factor in developing DCS. Level of Evidence: 3

The Effect of Lumbar Spinal Muscle on Spinal Sagittal Alignment: Evaluating Muscle Quantity and Quality.

BACKGROUNDnThe majority of earlier studies of the parameters of sagittal balance did not consider the influence of spinal muscles on spinal sagittal alignment.nnnOBJECTIVEnTo analyze the relationship between the paraspinal muscle (quantity and quality) and sagittal alignment in elderly patients.nnnMETHODSnWe reviewed 50 full-spine lateral standing radiographs and lumbar magnetic resonance images of elderly patients at a single center. The radiographic parameters examined were thoracic kyphosis, lumbar lordosis (LL), sagittal vertical axis, pelvic tilt, sacral slope, and pelvic incidence (PI). The lumbar muscularity (LM; quantity) and fatty degeneration ratio (FD; quality) in the paraspinal muscle were measured at the L3 level on magnetic resonance images. The relationships between the parameters, LM, and FD were analyzed with the Pearson correlation coefficient and multiple linear regression.nnnRESULTSnPearson analysis demonstrated that the FD had significant correlations with age (r = 0.393), thoracic kyphosis (r = -0.559), pelvic tilt (r = 0.430), sagittal vertical axis (r = 0.488), and PI - LL (r = 0.479, P < .05), and a close negative correlation was found between the FD and LL (r = -0.505, P < .01). The LM had significant correlations with the LL (r = 0.342) and PI - LL (r = -0.283, P < .05). Regression models that controlled for confounding factors such as body mass index confirmed the correlations between the above parameters and FD (P < .05).nnnCONCLUSIONnThe quality of the paraspinal muscle could be one of the various factors that influence sagittal balance.nnnABBREVIATIONSnBMI, body mass indexCSA, cross-sectional areaFD, fatty degeneration ratioLL, lumbar lordosisLM, lumbar muscularityPI, pelvic incidencePT, pelvic tiltSC, subcutaneous fatSS, sacral slopeSVA, sagittal vertical axisTK, thoracic kyphosisVB, vertebral body.

Efficacy of Antibiotics Sprayed into Surgical Site for Prevention of the Contamination in the Spinal Surgery.

Study Design Retrospective study. Purpose To evaluate the effect of intraoperative wound application of vancomycin on preventing surgical wound contamination during instrumented lumbar spinal surgery. Overview of Literature Postoperative infection is the one of the most devastating complications of lumbar surgery. There are a few reports showing the benefits of intraoperative wound application of vancomycin during spinal surgery. However, there is no report about the effectiveness of local vancomycin instillation in prevention of surgical wound contamination. Methods Eighty-six patients underwent instrumented lumbar spinal surgery. Mean patient age was 65.19 years (range, 23-83 years). There were 67 females and 19 males. During surgery, vancomycin powder was applied into the surgical site before closure in 43 patients (antibiotic group) and vancomycin powder was not applied into the surgical site before closure in 43 patients (control group). The tip of the surgical drain was cultured to evaluate surgical wound contamination. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were measured on the first, third, seventh, and fourteenth day after the operation. Results We found two patients with a positive culture from the tip of surgical drains in the antibiotic group, and one patient with a positive culture from the tip of the surgical drain in the control group. Postoperative ESR and CRP levels did not show significant differences between the two groups. On the third postoperative day, ESR in patients of the antibiotic group was more significantly decreased than that in patients of the control group, while CRP level did not show a significant difference between the two groups. Conclusions There was no evidence to suggest that intraoperative vancomycin application is effective in decreasing the risk of postoperative wound infection after instrumented posterior lumbar fusion surgery.

Radiographic Comparison between Cervical Spine Lateral and Whole-Spine Lateral Standing Radiographs

Study Design Retrospective radiologic study. Objective The sagittal alignment of the cervical spine can be evaluated using either a lateral cervical radiograph or a whole-spine lateral view on which the cervical spine is included. To our knowledge, however, no report has compared the two. The purpose of this work is to identify the difference in radiographic parameters between the cervical spine lateral view and the whole-spine lateral view. Methods We retrospectively analyzed 59 adult patients suffering from neck pain with cervical spine lateral radiographs and whole-spine lateral radiographs from November 2007 to December 2011. The radiographs were measured using standard techniques to obtain the following parameters from the two different radiographs: occipital–C2 angle, C2–C7 angle, C7–sternal angle, sternal slope, T1 slope, C2 central offset distance, the distance between C2 and C7 plumb lines, C4 anteroposterior (AP) diameter, the ratio of C2 central off distance to C4 AP diameter, the ratio of plumb lines’ distance to C4 AP diameter. Results We found that the occipital–C2 angle, sternal slope, and C4 AP diameter were similar, but the C2–C7 angle, C7–sternal angle, T1 slope, C2 central offset distance, distance between C2 and C7 plumb lines, ratio of C2 central off distance to C4 AP diameter, and ratio of plumb lines’ distance to C4 AP diameter were different. However, the error of measurement was greater than the small angular and linear differences between the two views. Conclusions Most numerical values of the measured radiographic parameters appear to be different between the two views. However, the two views are comparable because the numerical differences were smaller than the errors of measurement.