Bong Soon Chang

Usefulness of Prone Cross-Table Lateral Radiographs in Vertebral Compression Fractures

Background Dynamic radiographs are recommended to investigate non-healing evidence such as the dynamic mobility or intravertebral clefts in osteoporotic vertebral compression fractures (VCFs). However, it is difficult to examine standing flexion and extension lateral radiographs due to severe pain. The use of prone cross-table lateral radiographs (PrLRs) as a diagnostic tool has never been proposed to our knowledge. The purpose of this study is to clarify the usefulness of PrLRs in diagnosis and treatment of VCFs. Methods We reviewed 62 VCF patients examined with PrLRs between January 1, 2008 and June 30, 2011. To compare the degree of pain provoked between standing extension lateral radiographs (StLRs) and PrLRs, numeric rating scale (NRS) scores were assessed and compared by a paired t-test. Vertebroplasty was done for 40 patients and kyphoplasty was done for 9 patients with routine manners. To assess the degree of postural reduction, vertebral wedge angles (VWA) and vertebral height ratios (VHR) were calculated by using preoperative StLRs, PrLRs, and postoperative lateral radiographs. Two variables derived from changes in VWA and VHR between preoperative and postoperative radiographs were compared by a paired t-test. Results The average NRS scores were 6.23 ± 1.67 in StLRs and 5.18 ± 1.47 in PrLRs. The degree of pain provocation was lower in using PrLRs than StLRs (p < 0.001). The average changes of VWA between preoperative and postoperative status were 5.24° ± 6.16° with PrLRs and 3.46° ± 3.47° with StLRs. The average changes of VHR were 0.248 ± 0.178 with PrLRs and 0.148 ± 0.161 with StLRs. The comparisons by two variables showed significant differences for both parameters (p = 0.021 and p < 0.001, respectively). The postoperative radiological status was reflected more precisely when using PrLRs than StLRs. Conclusions In comparison with StLR, the PrLR was more accurate in predicting the degree of restoration of postoperative vertebral heights and wedge angles, and provoked less pain during examination. The PrLR could be a useful diagnostic tool to detect intravertebral cleft or intravertebral dynamic instability.

Inter- and Intra-observer Reliability of MRI for Lumbar Lateral Disc Herniation

Background The authors analyzed inter- and intra-observer agreement with respect to interpretation of simple magnetic resonance T1- and T2-weighted axial and sagittal images for the diagnosis of lumbar lateral disc herniation, including foraminal and extraforaminal disc herniations. Methods Forty-two patients in whom lumbar lateral disc herniation was suspected or confirmed by simple magnetic resonance imaging at one institute between May 2003 and December 2004 were included. The magnetic resonance images consisting of T1- and T2-weighted axial and sagittal images, and these were reviewed blindly and independently by three orthopaedic spine surgeons in a random manner. The images were interpreted as positive or negative for lateral disc herniation on 2 different occasions 3 months apart. Results were analyzed using Cohens kappa statistic, and strengths of agreements were determined using the Landis and Koch criteria. Results The kappa values for inter-observer agreement averaged 0.234 (0.282, 0.111, and 0.308 respectively) on the first occasion, and 0.166 (0.249, 0.111, and 0.137 respectively) on the second occasion, with an overall mean value of 0.200. Thus, the strength of agreement was only slight-to-fair according to the Landis and Koch criteria. Kappa values for intra-observer agreement averaged 0.479 (0.488, 0.491, and 0.459 respectively), indicating moderate agreement. Conclusions The present study indicates that simple magnetic resonance imaging is not a reliable imaging modality for diagnosing lumbar lateral disc herniation. Another imaging study with improved diagnostic values should be developed to diagnose this pathologic finding.

Change in pain catastrophizing in patients with lumbar spinal surgery

BACKGROUND CONTEXTnEven though catastrophizing can negatively moderate the outcome of surgery for lumbar spinal stenosis (LSS), it is still unclear whether pain catastrophizing is an enduring stable or a dynamic structure related to pain intensity after spine surgery.nnnPURPOSEnThe purpose of this study was to determine whether catastrophizing would change in patients who undergo spinal surgery for LSS.nnnSTUDY DESIGNnA prospective observational cohort study was carried out.nnnSTUDY SAMPLEnPatients who underwent spine surgery for LSS comprised the study sample.nnnOUTCOME MEASURESnThe Visual Analog Pain Scale (VAS) scores for back/leg pain, Oswestry Disability Index (ODI), and Pain Catastrophizing Scale (PCS) were the outcome measures.nnnMETHODSnThe present observational cohort consisted of 138 patients between the ages of 40 and 80 years who were scheduled to undergo surgery for LSS. Among them, a total of 96 patients underwent a 3-year assessment after surgery. The PCS questionnaire was used for pain catastrophizing assessment before and 3 years after surgery. The VAS for back and leg pain, and ODI were assessed 3 and 6 months, and 1 and 3 years after surgery. The correlations between variables were analyzed before and 3 years after surgery. To clarify the causal relationship, time-series and linear mixed models were also used.nnnRESULTSnAt 3 years after surgery, ODI, VAS for back and leg pain, and PCS scores were significantly decreased. The correlation of PCS with VAS and ODI was significant both before and 3 years after surgery. The correlation between change in pain or disability and change in pain catastrophizing from preoperative to 3 years after surgery was also significant. In the causal relationship between pain and catastrophizing, overall changes in pain and disability were significant predictors of overall changes in pain catastrophizing from baseline to 3 year after surgery.nnnCONCLUSIONnThe present study shows that pain catastrophizing can change in association with the improvement in pain intensity after spine surgery. Therefore, catastrophizing may not be an enduring stable construct, but a dynamic construct.

The influence of hand grip strength on surgical outcomes after surgery for degenerative lumbar spinal stenosis: a preliminary result

BACKGROUND CONTEXTnAlthough a number of prognostic factors have been demonstrated to be associated with surgical outcome of degenerative lumbar spinal stenosis (DLSS), no study has investigated the relation between hand grip strength (HGS) and treatment outcome of DLSS.nnnPURPOSEnThe purpose of the present study was to examine the influence of HGS on surgical outcomes after surgery for patients with DLSS.nnnSTUDY DESIGNnThis is an observational study.nnnPATIENT SAMPLEnPatients who underwent spine surgery for DLSS were included in the study.nnnOUTCOME MEASURESnOswestry Disability Index (ODI), EuroQOL (EQ-5D), and visual analog scale (VAS) scores for back or leg pain were assessed.nnnMATERIALS AND METHODSnA total of 172 consecutive patients who underwent spine surgery for DLSS were included in the present study. Patients were assigned to either high HGS group (≥26u2009kg for men and ≥18u2009kg for women, n=124) or low HGS group (<26u2009kg for men and <18u2009kg for women, n=48) based on their preoperative HGS performance. Oswestry Disability Index, EQ-5D, and VAS scores for back and leg pain were assessed and compared between two groups preoperatively, 3 and 6 months after surgery. The primary outcome measure was baseline-adjusted ODI scores 6 months after surgery. The secondary outcome measures, including the overall ODI score, EQ-5D score, VAS score for back and leg pain, were assessed at each time point during the 6-month follow-up period.nnnRESULTSnAs primary outcome, baseline-adjusted ODI scores were significantly lower in the high HGS group than in the low HGS group 6 months after surgery. In the secondary outcome measurements, the ODI, EQ-5D, and VAS scores for back and leg pain improved significantly with time after surgery in both groups. The effects of HGS group on the overall changes in the ODI and EQ-5D scores during the 6-month period were significantly different between the two groups; however, they were not significantly different on VAS score for back and leg pain. The pattern of change in the ODI during the follow-up period was significantly different between the two groups.nnnCONCLUSIONSnPatients with preoperative high HGS display better surgical outcome in terms of disability and health status 6 months after spine surgery. Preoperative HGS can act as a predictor of surgical outcome in patients with DLSS.

Comparative study of 1-year clinical and radiological outcomes using robot-assisted pedicle screw fixation and freehand technique in posterior lumbar interbody fusion: A prospective, randomized controlled trial

The purpose of this study was to compare the clinical outcome of surgery using robot‐assisted posterior interbody fusion with that using freehand posterior interbody fusion in patients with degenerative spinal disease.

Atlantoaxial Fixation using C2 Subarticular Screws and C1 Lateral Mass Screws - A Technical Report -

Segmental screw fixation is a useful procedure for the surgical treatment of atlantoaxial subluxation. Currently, C1 lateral mass screws and C2 pedicle screws are the standard screws used in this procedure. However, the C2 pedicle screw can cause serious complications such as vertebral artery injury. Recently we suggested a new trajectory for the C2 screw, the subarticular screw, which has a lower probability of vertebral artery injury compared with the pedicle screw, based on a study using 1 mm-sliced CT scan images and simulation software. We report the first case of segmental screw fixation using C2 subarticular screws along with C1 lateral mass screws. The patient had atlantoaxial subluxation and myelopathy and showed satisfactory results after surgery.

Atlanto-occipital Assimilation Associated with Basilar Invagination, C1-2 Instability, C2-3 Block Vertebra,and C3-4 Retrolisthesis : A Case Report

Congenital atlanto-occipital assimilation is frequently accompanied by basilar invagination and C1-2 instability. Occipitocervical fusion is required if these conditions cause neurological symptoms. Recently posterior fusion using occipitocervical screw fixation in the extension position has been introduced for the simultaneous decompression of the cervicomedullary junction compressed by basilar invagination, a reduction of atlantoaxial subluxation, and rigid fixation. However, it is a technically demanding procedure, and there is no domestic report of an experience with this procedure. We report a case of a patient with C2-3 block vertebra and C3-4 retrolisthesis in addition to congenital atlanto-occipital assimilation, basilar invagination and C1-2 instability. The patient underwent posterior fusion using occipitocervical screw fixation in the extension position.

Computer-assisted Evaluation of Pedicle Screw Position on CT Images

Purpose : The purpose of this study was to develop a personal computer-based method to facilitate the evaluation of pedicle screw position on computed tomography (CT) scan images and to assess its diagnostic value. Material and method : A personal computer-based method was developed using the CT images of 17 patients having a total of 84 pedicle screws. Images with a window range of -2,000 to +3,000 were inverted; a multiplanar reconstruction viewer was then produced to create these images in the sagittal and coronal planes. Finally, lines circumscribing the threaded portion of screws were drawn on the images. For CT images of thirty-two pedicle screws placed in the lumbar vertebrae of four pigs, screw locations were evaluated by 6 orthopaedic surgeons by our method and by conventional bone window setting. The diagnostic values of the two methods were calculated and compared. Result : Our method significantly improved the specificity (from 82% to 94%, p=0.007), the positive predictive value (from 79% to 92%, p=0.015), and inter-observer agreement (from 0.61 to 0.78, p