Chang-Nam Kang

Surgical Correction of Fixed Kyphosis

Study Design A retrospective review was carried out on 23 patients with rigid fixed kyphosis who underwent surgical correction for their deformity. Purpose To report the results of surgical correction of fixed kyphosis according to the surgical approaches or methods. Overview of Literature Surgical correction of fixed kyphosis is more dangerous than the correction of any other spinal deformity because of the high incidence of paraplegia. Methods There were 12 cases of acute angular kyphosis (6 congenital, 6 healed tuberculosis) and 11 cases of round kyphosis (10 ankylosing spondylitis, 1 Scheuermanns kyphosis). Patients were excluded if their kyphosis was due to active tuberculosis, fractures, or degenerative lumbar changes. Operative procedures consisted of anterior, posterior and combined approaches with or without total vertebrectomy. Anterior procedure only was performed in 2 cases, while posterior procedure only was performed in 8 cases. Combined procedures were used in 13 cases, including 4 total vertebrectomies. Results The average kyphotic angle was 71.8° preoperatively, 31.0° postoperatively, and the average final angle was 39.2°. Thus, the correction rate was 57% and the correction loss rate was 12%. In acute angular kyphosis, correction rate of an anterior procedure only was 71%, correction rate of the combined procedures without total vertebrectomy was 49% and correction rate of the combined procedures with total vertebrectomy was 60%. In round kyphosis, correction rate of posterior procedure only was 65% and correction rate of combined procedures was 59%. The clinical results according to the Kirkaldy-Willis scale demonstrated 17 excellent outcomes, 5 good outcomes and one poor outcome. Conclusions Our data indicates that the combined approach and especially the total vertebrectomy showed the safety and the greatest correction rate if acute angular kyphosis was greater than 60 degrees.

Height Restoration after Balloon Kyphoplasty in Rheumatoid Patients with Osteoporotic Vertebral Compression Fracture

Study Design Retrospective study. Purpose This study was conducted to compare vertebral body height restoration rate in rheumatoid arthritis (RA) patients who had undergone percutaneous balloon kyphoplasty (KP) with that of control group who had matched age, sex, body mass index, and bone mineral density. Overview of Literature There is no report on result of KP in RA patients. Methods Postoperative height restoration rate of RA group consisting of 15 patients (18 vertebral bodies) who had undergone KP due to osteoporotic vertebral compression fracture with a 30% or higher vertebral compression rate between May 2005 and January 2013 were compared to control group consisting of 38 patients (39 vertebral bodies) who had matched age, sex, body mass index, and bone mineral density. Results No statically significant difference in age (p=0.846), sex (p=0.366), body mass index (p=0.826), bone mineral density (p=0.349), time to surgery (p=0.528), polymethylmethacrylate injection time (p=0.298), or amount (p=0.830) was found between the RA group and the control group. However, preoperative compression rate in the RA group was significantly (p=0.025) higher compared to that in the control group. In addition, postoperative height restoration rate showed significant correlation with the RA group (p=0.008). Although higher incidence of recollapse occurred in the RA group compared to that in the control group, the difference was not statistically significant (p=0.305). Conclusions Compared to the control group, RA patients showed higher compression rate and higher vertebral restoration rate after KP, indirectly indicating weaker bone quality in patients with RA. Higher incidence of recollapse occurred in the RA group compared to that in the control group, although it was not statistically significant.

Arachnoid ossificans of thoracolumbosacral spine in the advanced ankylosing spondylitis: a case report

Arachnoid ossificans is a rare type of chronic arachnoiditis characterised by the presence of calcification or ossification of the dura and arachnoid. There are a few reports of these findings in relation to various disease entities, but only one case has been reported in relation to ankylosing spondylitis. We describe a 76-year-old man of ankylosing spondylitis with arachnoiditis ossificans, who has suffered from low back pain and neuropathic leg pain.

Anterior operation for unstable thoracolumbar and lumbar burst fractures: tricortical autogenous iliac bone versus titanium mesh cage.

Study Design: We retrospectively compared 25 cases that used the autogenous iliac bone grafting with 18 cases that used a titanium mesh cage for reconstruction of the vertebral body. Objective: To analyze clinical and radiographic results of the autogenous iliac bone and a titanium mesh cage used to reconstruct the vertebral body. Summary of Background Data: Grafting of the autogenous iliac bone as a strut bone has been traditionally applied for reconstruction of the spine using anterior approach. Although grafting the autogenous iliac bone as a strut bone achieves a high bone fusion rate, it has reported complications in the donor site. For this reason, bone fusion with a mesh cage has been introduced. Methods: Between March 2000 and December 2010, 43 cases that underwent decompression and instrumented fusion for unstable burst fractures using the anterior approach were enrolled. Levels of injury were T12 in 8 cases, L1 in 19 cases, L2 in 11 cases, and L3 in 5 cases. The mean follow-up period was 64.5 months (range, 14–129 mo). Results: The local kyphotic angle in the group that used the tricortical autogenous iliac bone (group A) was measured 24.81±2.27 degrees preoperatively and 4.95±0.61 degrees at the last follow-up. The angle in the group that used a titanium mesh cage (group B) was 25.21±1.55 degrees preoperatively and 3.9±0.43 degrees at the last follow-up. Both groups obtained bone fusion of grade I and II by Bridwell fusion criteria. The operation site visual analog scale and Korean Oswestry disability index did not differ significantly between 2 groups. Donor site visual analog scale and the operation time was significantly in favor of group B (P<0.05). Conclusions: Titanium mesh cage filled with the autogenous cancellous bone shortened operation time and reduced the risk of complications in the donor site compared with the group that used the tricortical iliac bone.

Cost-effectiveness Analysis of Existing Pedicle Screws Reusing Technique in Extension Revision Operation for Adjacent Segmental Stenosis After Lumbar Posterolateral Fusion

Study Design. Retrospective case-control study. Objective. A cost-effectiveness analysis was performed by comparing patients who received extension revision operations for adjacent segment disease (ASD) reusing the pedicle screws extracted from fused segments with patients who received conventional surgery. Summary of Background Data. ASD often required extension revision surgery, and during extension surgery, pedicle screws may be reused by extracting from the fused segments of primary surgery. Methods. Study examined 37 patients who received extension revision surgery for ASD from January 2003 to December 2013. For the fixation of extended segments during revision operation, in 16 cases the pedicle screws extracted from fused segments were reused (group R), and in 21 cases new pedicle screws were used (group C) as a conventional method. Clinical outcomes were evaluated by means of visual analog scale scores for lumbago and leg pain, and the Korean Oswestry Disability Index. Radiologic outcomes were evaluated from the extent of bone union. The total operating costs in the two groups were compared. Results. Visual analog scale scores for lumbago and leg pain, and the Korean Oswestry Disability Index measured at final follow-up averaged 3.6 and 3.8, and 19.9 in group R, and 3.8 and 3.1, and 21.1 in group C, respectively (P = 0.280, P = 0.387, P = 0.751). For radiologic outcomes, there was one case of nonunion in each group. The cost of surgery was 5332 US dollars in group R, and 6109 US dollars in group C, respectively (P = 0.036). Conclusion. Reusing pedicle screws extracted from the fused segments during extension revision operation for ASD can reduce the cost of surgery, and achieves clinical and radiological results similar to those of the conventional operation. Level of Evidence: 4.

Quantitative computed tomography assessment of bone mineral density after 2 years’ oral bisphosphonate treatment in postmenopausal osteoarthritis patients who underwent total knee arthroplasty

Objectives To identify the effects of two years’ oral bisphosphonate (alendronate) treatment in patients who underwent total knee arthroplasty (TKA); to determine whether significant responses seen after the first year of treatment changed during the second year. Additionally, the study tried to identify factors relating to bone mineral density (BMD) changes. Methods This was a prospective 2-year follow-up study of a previous 1-year report of postmenopausal women with knee osteoarthritis who underwent primary unilateral or staged bilateral TKA, after which they received 70 mg alendronate orally once-weekly. BMD was measured using quantitative computed tomography (QCT) on lumbar vertebrae at baseline (pre-TKA) and at 12 and 24 months. Factors associated with BMD changes were determined by regression analysis. Results Sixty-one patients entered the second year and continued treatment for ≥24 months. Mean vertebral QCT BMDs at baseline and after 12 and 24 months’ alendronate treatment were 71.8 mg/ml (41.9–97.5 mg/ml), 69.3 mg/ml (31.4–103.9 mg/ml), and 72.7 mg/ml (33.1–136.1 mg/ml), respectively. Patients undergoing bilateral TKA and who had more severe OA at baseline (bilateral severe [grade 4] OA) had a lower BMD response after 2 years’ bisphosphonate treatment, compared with patients with less severe unilateral knee OA who underwent unilateral TKA. Improvements were, however, seen compared with year 1 levels. Low BMI was associated with BMD nonresponse. Conclusions Patients with bilateral severe OA (grade 4) requiring bilateral knee replacement are at greater risk of nonresponse after 2 years’ oral alendronate treatment. A longer duration of treatment may be necessary in these patients.

Percutaneous balloon kyphoplasty for the treatment of very severe osteoporotic vertebral compression fractures: a case-control study

BACKGROUND CONTEXT Controversy exists regarding percutaneous balloon kyphoplasty (PBK) in patients with a very severe osteoporotic vertebral compression fracture (vsOVCF). PURPOSE The study was conducted to investigate the clinical and radiological outcomes of PBK for the treatment of vsOVCF compared with those of non-vsOVCF. STUDY DESIGN/SETTING This is a retrospective, case-control study. PATIENT SAMPLE A total of 167 consecutive patients (210 vertebral bodies) who underwent PBK for OVCF between March 2010 and January 2015 were assessed. OUTCOME MEASURES Visual analog scale (VAS) scores for back pain, Korean Oswestry disability index (K-ODI) scores, vertebral body height variations, and kyphotic angles were evaluated preoperatively, postoperatively, and 1 year after treatment. MATERIALS AND METHODS Patients in the non-vsOVCF group (anterior vertebral compression of more than two-thirds on plain radiograph) who had undergone PBK where compared with those in the non-vsOVCF group (compression between 30% and two-thirds). Clinical and radiological outcomes were compared. In addition, complications were evaluated. RESULTS In total, 31 patients (33 vertebrae) in the vsOVCF group and 136 patients (177 vertebrae) in the non-vsOVCF group were treated with PBK. Both groups had significant postoperative improvements in the clinical and radiological outcomes (VAS score, K-ODI score, vertebral body height variation, and kyphotic angle). There was no difference regarding the VAS score and the K-ODI score between the two groups at the final follow-up (p>.05). The cement leakage occurred frequently in the vsOVCF group (26 vertebrae, 78.8%) than in the non-vsOVCF group (92 vertebrae, 52.0%), the difference was statistically significant (p<.05). But there was no case that showed neurologic complication or pulmonary embolism caused by cement leakage. The incidence of recollapse was significantly higher in the vsOVCF group (five vertebrae, 15.2%) than in the non-vsOVCF group (seven vertebrae, 4.0%) (p<.05). The incidence of an adjacent segment fracture (vsOVCF group, 6 vertebrae, 18.2%; non-vsOVCF group, 21 vertebrae, 11.9%) was not significantly different (p=.320). CONCLUSIONS Percutaneous balloon kyphoplasty is a safe and effective procedure for the treatment of vsOVCF.

Outcomes of Revision Surgery Following Instrumented Posterolateral Fusion in Degenerative Lumbar Spinal Stenosis: A Comparative Analysis between Pseudarthrosis and Adjacent Segment Disease

Study Design Retrospective study. Purpose We examined the clinical and radiological outcomes of patients who received revision surgery for pseudarthrosis or adjacent segment disease (ASD) following decompression and instrumented posterolateral fusion (PLF). Overview of Literature At present, information regarding the outcomes of revision surgery for complications such as pseudarthrosis and ASD following instrumented PLF is limited. Methods This study examined 60 patients who received PLF for degenerative lumbar spinal stenosis and subsequently developed pseudarthrosis or ASD leading to revision surgery. Subjects were divided into a group of 21 patients who received revision surgery for pseudarthrosis (Group P) and a group of 39 patients who received revision surgery for ASD (Group A). Clinical outcomes were evaluated using the visual analogue scales for back pain (VAS-BP) and leg pain (VAS-LP), the Korean Oswestry disability index (K-ODI), and each patients subjective satisfaction. Radiological outcomes were evaluated from the extent of bone union, and complications in the two groups were compared. Results VAS-LP at final follow-up was not statistically different between the two groups (p =0.353), although VAS-BP and K-ODI at final follow-up were significantly worse in Group P than in Group A (all p <0.05), and only 52% of the patients in Group P felt that their overall well-being had improved following revision surgery. Fusion rates after the first revision surgery were 71% (15/21) in Group P and 95% (37/39) in Group A (p =0.018). The rate of reoperation was significantly higher in Group P (29%) than in Group A (5%) (p =0.021) due to complications. Conclusions Clinical and radiological outcomes were worse in patients who had received revision surgery for pseudarthrosis than in those who had revision surgery for ASD. Elderly patients should be carefully advised of the risks and benefits before planning revision surgery for pseudarthrosis.

Risk Factors for Newly Developed Osteoporotic Vertebral Compression Fractures Following Treatment for Osteoporotic Vertebral Compression Fractures

BACKGROUND CONTEXT It has been reported that newly developed osteoporotic vertebral compression fractures (OVCFs) occur at a relatively high frequency after treatment. While there are many reports on possible risk factors, these have not yet been clearly established. PURPOSE The purpose of this study was to investigate the risk factors for newly developed OVCFs after treatment by vertebroplasty (VP), kyphoplasty (KP), or conservative treatment. STUDY DESIGN/SETTING A retrospective comparative study. PATIENT SAMPLE One hundred thirty-two patients who had radiographic follow-up data for one year or longer among 356 patients who were diagnosed with OVCF and underwent VP, KP or conservative treatment between March 2007 and February 2016. OUTCOME MEASURES All records were examined for age, sex, body mass index (BMI), rheumatoid arthritis and other medical comorbidities, osteoporosis medication, bone mineral density (BMD), history of vertebral and nonvertebral fractures, treatment methods used, level of fractures, and presence of multiple fracture sites. METHODS Patients were divided into those who manifested new OVCF (Group A) and those who did not (Group B). For the risk factor analysis, students t-tests and chi-square tests were used in univariate analysis. Multivariate logistic regression analysis was carried out on variables with a p<.1 in the univariate analysis. RESULTS Newly developed OVCFs occurred in 46 of the 132 patients (34.8%). Newly developed OVCF increased significantly with factors such as average age (p=.047), low BMD T-score of the lumbar spine (p=.04) and of the femoral neck (p=.046), advanced age (>70 years) (p=.011), treatment by cement augmentation (p=.047) and low compliance with osteoporosis medication (p=.029). In multivariate regression analysis, BMD T-score of the lumbar spine (p=.009) and treatment by cement augmentation (p=.044) showed significant correlations with the occurrence of new OVCFs with a predictability of 71.4%. CONCLUSION Osteoporotic vertebral compression fracture patients with low BMD T-score of the lumbar spine and those who have been treated by cement augmentation have an increased risk of new OVCFs after treatment and, therefore, require especially careful observation and attention.