Jae-Hyuk Shin

Comparison of posterolateral fusion with and without additional posterior lumbar interbody fusion for degenerative lumbar spondylolisthesis.

Objectives The surgical approach that should be used for degenerative spondylolisthesis (DS) is a controversial issue. Decompression and posterolateral fusion (PLF) with or without lumbar interbody fusion is widely used. Many studies have compared the outcomes of these 2 approaches, but the appropriate indications for these approaches are still unclear. The authors retrospectively studied the effects of posterior lumbar interbody fusion (PLIF) after PLF for the treatment of DS. Methods Forty patients who underwent single level decompression and posterior instrumentation for DS at L4-5 and were followed for at least 2 years were retrospectively studied. The patients were divided into 4 groups: the stable PLF group (S-PLF, n=13); the stable PLF with additional PLIF group (S-PLIF, n=11); the unstable PLF group (U-PLF, n=8); and the unstable PLF with additional PLIF group (U-PLIF, n=8). Clinical and radiographic comparisons were carried out between the S-PLF and S-PLIF groups, and between the U-PLF and U-PLIF groups. Results Clinical assessments, using the improvements of the Oswestry Disability Index (ODI) and the Visual Analog Scale (VAS), were statistically significantly different between the 2 unstable groups (ΔU-PLF <ΔU-PLIF, P(ODI)=0.032, P(VAS)=0.004, respectively). On radiologic assessment, the slip angle increment was significantly different between the 2 stable groups (ΔS-PLF>ΔS-PLIF, P=0.029), and the disc height increment was significantly different between the 2 stable groups (ΔS-PLF<ΔS-PLIF, P=0.043) and between the 2 unstable groups (ΔU-PLF<ΔU-PLIF, P=0.042). Conclusions This study suggests that preoperative segmental instability may be a criterion determining whether an additional PLIF would be beneficial in the treatment of lumbar DS.

The fate of anterior autogenous bone graft after anterior radical surgery with or without posterior instrumentation in the treatment of pyogenic lumbar spondylodiscitis.

Study Design. A retrospective clinical study. Objective. To assess the results of anterior strut grafting and the loss of the reduction in anterior interbody fusion and anterior interbody fusion combined with posterior instrumental fusion in pyogenic spondylodiscitis. Summary of Background Data. Resorption of the anterior graft is an ominous sign following most anterior surgery. Thus, additional posterior instrumentation has been used to prevent collapse of the anterior graft. However, its effect is controversial, and few studies have examined the fate of the anterior strut graft. Methods. Twenty-four consecutive patients underwent surgical treatment for pyogenic spondylodiscitis. The patients were divided into Group I (anterior interbody fusion) and Group II (anterior interbody fusion + posterior instrumented fusion). The sagittal angle, intervertebral height, and complications relating to the anterior graft were compared. Results. Solid bone fusion was achieved in 23 (95.8%) patients. The sagittal angle and the intervertebral height were similar in Groups I and II (P = 0.61, P = 0.89, respectively). In Groups I and II, the postoperative sagittal angle was maintained until 1 month after surgery (P > 0.05), but it decreased significantly by 3 months after surgery (P < 0.05). In Groups I and II, intervertebral height correction was maintained until 1 month after surgery (P > 0.05), but by 3 months after surgery, it had collapsed significantly (P < 0.05). Subsidence of the graft occurred through the damaged endplate. Group I included 1 case of graft dislodgement necessitating revision; there were no such cases in Group II. There were no recurrences of infection in either group. Conclusion. Reduction of intervertebral height and loss of sagittal profile occurred in both groups. Complications relating to the bone graft were more common in Group I than in Group II. Despite loss of correction, both groups had a high fusion rate without recurrence of infection. The reduction of intervertebral graft height appears to be the result of destruction of the endplate either due to surgical debridement or the infective process.

Surgical treatment for delayed pyogenic spondylitis after percutaneous vertebroplasty and kyphoplasty. Report of 4 cases.

Only 6 cases of pyogenic spondylitis following vertebroplasty or kyphoplasty have been reported, and their causes remained unclear. The authors report on 4 cases of delayed pyogenic spondylitis (DPS) following vertebroplasty or kyphoplasty for osteoporotic compression fractures and metastatic disease. Four patients presented with DPS after vertebroplasty or kyphoplasty and underwent surgical treatment. Clinical history, laboratory examination, and MR imaging confirmed the diagnosis of DPS. Anterior debridement, reconstruction, and posterior instrumented fusion were performed. The mean interval for the delayed occurrence of pyogenic spondylitis after surgery was 12.3 months. The infections were primarily bacterial in origin, but most patients also suffered diverse medical comorbidities. Despite successful treatment of the infections, comorbidity was and is a factor that compromises good results. Medical comorbidities associated with compromised immunity may increase susceptibility to DPS after vertebroplasty or kyphoplasty. In cases of incapacitating back pain after a pain-free period following either of these surgeries, evaluation of the erythrocyte sedimentation rate and C-reactive protein level and examination of contrast-enhanced MR imaging studies are essential to rule out delayed vertebral infection. Surgical treatment requires cement removal and anterior reconstruction with or without additional posterior instrumented fusion.

Loss of Lordosis and Clinical Outcomes after Anterior Cervical Fusion with Dynamic Rotational Plates

Purpose The cervical dynamic rotational plating system may induce bone graft subsidence, so it may cause loss of cervical lordosis. However there were few studies for alignments of cervical spines influencing the clinical results after using dynamic rotational plates. The purpose is to evaluate the effect of graft subsidence on cervical alignments due to the dynamic rotational cervical plates and correlating it with the clinical outcomes of patients undergoing anterior cervical fusion. Materials and Methods Thirty-three patients with disease or fracture underwent anterior cervical decompression and fusion using a dynamic rotational plate. The presence and extent of implant complications, graft subsidence, loss of lordosis were identified and Visual Analog Scale score (VAS score), Japanese Orthopaedic Association score (JOA score), clinical outcomes based on Odoms criteria were recorded. Results Fusion was achieved without implant complications in all cases. The mean graft subsidence at 6 months after the surgery was 1.46 mm. The lordotic changes in local cervical angles were 5.85° which was obtained postoperatively. VAS score for radicular pain was improved by 5.19 and the JOA score was improved by 3. Clinical outcomes based on Odoms criteria showed sixteen excellent, ten good and two satisfactory results. There was no significant relationship between clinical outcomes and changes in the cervical angles. Conclusion Dynamic rotational anterior cervical plating provides comparable clinical outcomes to that of the reports of former static cervical platings. The loss of lordosis is related to the amount of graft settling but it is not related to the clinical outcomes.

Genetic predisposition in degenerative lumbar scoliosis due to the copy number variation.

Study Design. Comparative genomic hybridization (CGH) microarrays. Objective. To identify genomic copy number variations (CNVs) in degenerative lumbar scoliosis (DLS) patients, and investigate the possibility of genetic predisposition in DLS. Summary of Background Data. Genome scanning technology enables search for presence of CNVs. CGH microarray is a useful procedure in a genome-wide study. Methods. Among 45 consecutive patients who were diagnosed as DLS, 15 patients who manifested greatest Cobbs angle were selected for the array-CGH based CNV analysis. Control group was blood samples from 58 individuals without DLS. Oligonucleotide CGH microarray was utilized to analyze the CNV. Gene searches were performed for CNV DNA with significant gene-dosage difference. Validation qualitative PCR(qPCR) was performed at 3 genetic loci: at chromosome 2-TMEM163 gene, at chromosome 16 - ANKRD 11 gene, and at chromosome 18 - NFATC1 gene. Results. Genomic gains and losses were observed using the oligonucleotide CGH microarray. Identified CNVs were 446 ± 129 per individual. Gain- and loss-CNVs were identified as 196 ± 24 and 250 ± 110, respectively. The length of total CNV per individual was 30,946,730 ± 31,658,175 bp, and mean CNV-length was 61,017 ± 40,620 (median length 6411 ± 1994). Comparison with control group revealed 260 CNVs, which were significant (P < 10−3). Validation qPCR for gene-dosage comparison of DLS group DNA versus control group DNA in TMEM163 (P < 0.001); ANKRD 11 (P = 0.000); and NFATC1 (P = 0.000) gene showed significant difference. Conclusion. Various whole-genome CNVs specific to DLS patients were observed. Validation qPCR confirmed significantly different gene-dosages for TMEM163, ANKRD 11, and NFATC1 genes. We consider that the expression of DLS is supported by various typical CNV-associated structural variants of the genome.

Lumbar Facet Joint Motion in Patients with Degenerative Spondylolisthesis

Study Design: Controlled laboratory study. Objective: To investigate the in vivo biomechanical effect of degenerative lumbar spondylolisthesis (DLS) on the motion of the facet joint during various functional weight-bearing activities. Summary of Background Data: Although the morphologic changes of the facet joints in patients with DLS have been reported in a few studies, no data have been reported on the kinematics of these facet joints. Methods: Ten patients with DLS at L4–L5 were studied. Each patient underwent a magnetic resonance imaging scan to obtain 3-dimensional models of the lumbar vertebrae from L2–L5 and a dual fluoroscopic imaging scan in different postures: flexion-extension, left-right bending, and left-right torsion. The positions of the vertebrae were reproduced by matching the magnetic resonance imaging–based vertebral models to the fluoroscopic images. The kinematics of the facet joint and the ranges of motion were compared with those of healthy subjects and those of patients with degenerative disk diseases (DDD) previously published. Results: In DLS patients, the range of rotation of the facet joints was significantly less at the DLS level (L4–L5) than that at the adjacent levels (L2–L3 and L3–L4), whereas the range of translation was similar at all levels. The range of rotation at the facet joints of the DLS level decreased compared with those of both the DDD patients and healthy subjects at the corresponding vertebral level (L4–L5), whereas no significant difference was found in the range of translation. The range of motion of facet joints in DLS and in DDD patients was similar at the adjacent levels (L2–L3 and L3–L4). Conclusions: The range of rotation decreased at the facet joints at the DLS level (L4–L5) in patients compared with those in healthy subjects and DDD patients. This decrease in range of rotation implies that the DLS disease may cause restabilization of the joint. The data may help the selection of conservative treatment or different surgical techniques for the DLS patients.

Kyphotic Angle Progression of Thoracic and Thoracolumbar Tuberculous Spondylitis after Surgical Treatment: Comparison with Predicted Kyphosis Outcome after Conservative Treatment

Study Design Retrospective comparative study. Purpose To compare the progression of the kyphotic angle (KA) in a surgically treated group with the predicted outcome of a conservatively treated group. Overview of Literature Late onset kyphosis is a complication of tuberculous spondylitis making its prevention a major goal of surgery. Methods Twenty six consecutive patients underwent an anterior reconstruction and posterior instrumented fusion in conjunction with antituberculous chemotherapy. The mean follow up was 56 months (range, 28 to 112 months). The patients were divided into subgroups based on the involved region of the thoracic and the thoracolumbar spine, initial KA, and the initial vertebral body loss (VBL(x)). The predicted KA (KAPd) was calculated using the formula, KAPd=5.5+30.5 VBL(x), to predict the final gibbus deformity. Kyphotic angle progression (ΔKA) based on the radiographic measurements after surgery (ΔKAR), and the predicted outcome of conservative treatment (ΔKAP) with chemotherapy were compared. Results Among the subgroups of the regions involved and initial KA, the ΔKA was radiographically superior with a reduced amount of kyphogenesis in the surgery group than the predicted outcome of the conservatively treated patients (p<0.05). The radiographic ΔKA was similar (p>0.05) with VBL(x)≤0.5 in the VBL(x) subgroup. Conclusions These results showed that in the VBL(x) subgroup, an initial VBL(x)≤0.5 is an indication of conservative antituberculous chemotherapy without surgery.

Delayed Infrarenal Aortic Pseudoaneurysm Treated by Endovascular Stent Graft in Pyogenic Spondylitis

A 61-year-old male patient with pyogenic spondylodiscitis and epidural and psoas abscesses underwent posterior decompression, debridement, and instrumented fusion, followed by anterior debridement and reconstruction. Sudden onset flank pain was diagnosed 7 weeks postoperatively and was determined to be a pseudoaneurysm located at the aorta inferior to the renal artery and superior to the aortic bifurcation area. An endovascular stent graft was applied to successfully treat the pseudoaneurysm. Postoperative recovery was uneventful and infection status was stabilized.

Preliminary Report of Three-Dimensional Reconstructive Intraoperative C-Arm in Percutaneous Vertebroplasty

Objective Percutaneous vertebroplasty (PVP) is usually carried out under three-dimensional (2D) fluoroscopic guidance. However, operative complications or bone cement distribution might be difficult to assess on the basis of only 2D radiographic projection images. We evaluated the feasibility of performing an intraoperative and postoperative examination in patients undergoing PVP by using three-dimensional (3D) reconstructive C-arm. Methods Standard PVP procedures were performed on 14 consecutive patients by using a Siremobil Iso-C3D and a multidetector computed tomography machine. Post-processing of acquired volumetric datasets included multiplanar reconstruction (MPR) and surface shaded display (SSD). We analyzed intraoperative and immediate postoperative evaluation of the needle trajectory and bone cement distribution. Results The male : female ratio was 2 : 12; mean age of patients, 70 (range, 77-54) years; and mean T score, -3.4. The mean operation time was 52.14 min, but the time required to perform and post-process the rotational acquisitions was 7.76 min. The detection of bone cement distribution and leakage after PVP by using MPR and SSD was possible in all patients. However, detection of the safe trajectory for needle insertion was not possible. Conclusion 3D rotational image acquisition can enable intra- or post-procedural assessment of vertebroplasty procedures for the detection of bone cement distribution and leakage. However, it is difficult to assess the safe trajectory for needle insertion.

The Trajectory of Iliac Screw in the Axial Plane in 200 Korean Patients

Study Design A retrospective radiographic analysis. Purpose To estimate the accurate trajectory in the axial plane for iliac screw insertion in 200 Korean patients using radiographic images. Overview of Literature Several complications have been encountered after fusion to the lumbosacral junction, including pseudarthrosis, S1 screw loosening, and sacral fractures. Iliac screw fixation is considered an efficient method for augmenting sacral screw fixation but there are few reports on the trajectory of iliac screw insertion. The trajectory in the sagittal plane can be visualized by intraoperative fluoroscopy. However, there is no method to check the accuracy of the trajectory in the axial plane during surgery. Methods Between January 2007 and February 2009, 200 patients (107 men and 93 women) who underwent L-spine computed tomography were enrolled in this study. The mean age of the patients was 55.6 ± 18.3 years (range, 13 to 92 years). The spino-iliac angle (SIA) was measured on the axial image at the S1 level, which was defined as the angle between a vertical line through the center of the spinous process and an oblique line that passed through the center of the outer and inner cortices of the ilium. Results The group mean SIA was 30.1° ± 7.8°; 30.1° ± 7.7° for men and 29.9° ± 81.1° for women. There was no significant difference according to gender or age (p > 0.05). Conclusions The SIA for the axial trajectory of iliac screws is approximately 30° in Korean patients.