Po-Hsin Chou

Fusion may not be a necessary procedure for surgically treated burst fractures of the thoracolumbar and lumbar spines: a follow-up of at least ten years.

BACKGROUND The surgical results of treating thoracolumbar and lumbar burst fractures were reported to be comparable between patients with and without fusion in an intermediate-term follow-up. To our knowledge, no prior report has compared the results of fusion and non-fusion with long-term follow-up. METHODS This study was designed to provide long-term evaluation of patients with a burst fracture of the thoracolumbar and lumbar spine treated with short-segment fixation who were randomly assigned to a fusion or non-fusion group. Patients older than sixty years of age at the time of injury and those who were lost to follow-up were excluded. Functional outcomes were evaluated using the Greenough Low-Back Outcome Score and the visual analog scale for back pain. Radiographic outcomes were focused on the vertebral body height of the injured vertebra, the kyphotic angle, and the regional segmental motion. RESULTS Twenty-two patients were enrolled in the non-fusion group, and twenty-four patients were enrolled in the fusion group. The average follow-up period was 134 months (range, 121 to 161 months). The average preoperative kyphotic angle was 16.4° for the non-fusion group and 19.5° for the fusion group. The average postoperative kyphotic angle was 1.5° for the non-fusion group and 4.0° for the fusion group. At the time of the latest follow-up, the average kyphotic angle was 13.8° for the non-fusion group and 14.7° for the fusion group. The average kyphotic angle between the two groups was similar at all follow-up times. A progressive decrease of the kyphotic angle was significant (p < 0.05) with time, regardless of fusion. The radiographic outcomes were similar between these two groups at all follow-up times, as were functional outcomes. More patients in the non-fusion group underwent additional surgery to remove implants. Regional segmental motion was preserved in the non-fusion group, with a mean motion (and standard deviation) of 4.2° ± 1.9°. CONCLUSIONS The long-term results of short segmental fixation with and without fusion for burst fractures of the thoracolumbar and lumbar spine were comparable. Regional segmental motion could be preserved without fusion, and bone graft donor site complications could be eliminated. LEVEL OF EVIDENCE Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Does the size of the rod affect the surgical results in adolescent idiopathic scoliosis? 5.5-mm versus 6.35-mm rod.

BACKGROUND CONTEXT Favorable clinical outcomes of surgical treatment with Cotrel-Dubousset instrumentation (CDI) or instrumentations that follow the principles of CDI, for adolescent idiopathic scoliosis (AIS) have been reported. However, there are few studies concerning the results with rods of different sizes. PURPOSE To find out whether the rod size affects the surgical results for AIS. STUDY DESIGN A retrospective cohort study based on the same spinal system with different sizes of rod. PATIENT SAMPLE A consecutive series of 93 patients, who underwent posterior correction with posterior instrumentation and fusion for AIS, were included and retrospectively analyzed. OUTCOME MEASURES Postoperative radiologic outcomes were evaluated using coronal curves, percentage of curve correction, and coronal global balance. METHODS Ninety-three patients treated during the period January 2000 to December 2008 were included in this study; 48 patients were treated with the Cotrel-Dubousset Horizon (CDH) M10 system with a 6.35-mm rod from January 2000 through December 2004, and a CDH M8 was used with a 5.5-mm rod in another 45 patients from January 2005 through December 2008. The Cobb angle, Risser grade, coronal curves, flexibility of curve, percentage of curve correction, coronal global balance, operative time, and estimated blood loss were measured and analyzed. The same parameters were used when the patient was followed at the OPD. All of the patients underwent regular follow-up for at least 2 years. RESULTS No statistical significance was observed in the demographic data, including age, sex, BMI, and Risser grade, between these 2 groups. The overall average percentage of correction was 60.0%±12.7%: 60.7%±12.5% for the CDH M10 group, and 59%±13.1% for the CDH M8 group. At the final follow-up, the overall average loss of correction was 4.8±3.9° for the CDH M10 group, and 4.3±4.0° for the CDH M8 group. The average percentage of correction at the final follow-up was 50.9%±15.1% for the CDH M10 group, and 51.1%±16.1% for the M8 group. No statistical significance could be observed in the radiologic parameters between these 2 groups. CONCLUSION The radiologic results for the 5.5-mm rod and the 6.35-mm rod were comparable in terms of correction, loss of correction, and coronal global balance.

Is removal of the implants needed after fixation of burst fractures of the thoracolumbar and lumbar spine without fusion?: a retrospective evaluation of radiological and functional outcomes

METHODS In this study of patients who underwent internal fixation without fusion for a burst thoracolumbar or lumbar fracture, we compared the serial changes in the injured disc height (DH), and the fractured vertebral body height (VBH) and kyphotic angle between patients in whom the implants were removed and those in whom they were not. Radiological parameters such as injured DH, fractured VBH and kyphotic angle were measured. Functional outcomes were evaluated using the Greenough low back outcome scale and a VAS scale for pain. RESULTS Between June 1996 and May 2012, 69 patients were analysed retrospectively; 47 were included in the implant removal group and 22 in the implant retention group. After a mean follow-up of 66 months (48 to 107), eight patients (36.3%) in the implant retention group had screw breakage. There was no screw breakage in the implant removal group. All radiological and functional outcomes were similar between these two groups. Although solid union of the fractured vertebrae was achieved, the kyphotic angle and the anterior third of the injured DH changed significantly with time (p < 0.05). DISCUSSION The radiological and functional outcomes of both implant removal and retention were similar. Although screw breakage may occur, the implants may not need to be removed. TAKE HOME MESSAGE Implant removal may not be needed for patients with burst fractures of the thoracolumbar and lumbar spine after fixation without fusion. However, information should be provided beforehand regarding the possibility of screw breakage.

Anterior debridement may not be necessary in the treatment of tuberculous spondylitis of the thoracic and lumbar spine in adults: a retrospective study

AIM Many aspects of the surgical treatment of patients with tuberculosis (TB) of the spine, including the use of instrumentation and the types of graft, remain controversial. Our aim was to report the outcome of a single-stage posterior procedure, with or without posterior decompression, in this group of patients. PATIENTS AND METHODS Between 2001 and 2010, 51 patients with a mean age of 62.5 years (39 to 86) underwent long posterior instrumentation and short posterior or posterolateral fusion for TB of the thoracic and lumbar spines, followed by anti-TB chemotherapy for 12 months. No anterior debridement of the necrotic tissue was undertaken. Posterior decompression with laminectomy was carried out for the 30 patients with a neurological deficit. RESULTS The mean kyphotic angle improved from 26.1° (- 1.8° to 62°) to 15.2° (-25° to 51°) immediately after the operation. At a mean follow-up of 68.8 months (30 to 144) the mean kyphotic angle was 16.9° (-22° to 54°), with a mean loss of correction of 1.6° (0° to 10°). There was a mean improvement in neurological status of 1.2 Frankel grades in those with a neurological deficit. Bony union was achieved in all patients, without recurrent infection. CONCLUSIONS Long posterior instrumentation with short posterior or posterolateral fusion is effective in the treatment of TB spine. It controls infection, corrects the kyphosis, and maintains correction and neurological improvement over time. TAKE HOME MESSAGE With effective anti-TB chemotherapy, a posterior only procedure without debridement of anterior lesion is effective in the treatment of TB spondylitis, and an anterior procedure can be reserved for those patients who have not improved after posterior surgery. Cite this article: Bone Joint J 2016;98-B:834-9.

Determination of the painful level in osteoporotic vertebral fractures—Retrospective comparison between plain film, bone scan, and magnetic resonance imaging

Background Determining the actual painful vertebral level is difficult when evaluating osteoporotic vertebral fracture, especially when there are acute and chronic fractures simultaneously. In this study, we retrospectively evaluated and compared the findings between plain film, bone scan, and magnetic resonance imaging (MRI) in the diagnosis of new fracture in osteoporotic vertebral fractures. Methods This is a retrospective clinical study of patients who were diagnosed with osteoporotic vertebral fractures using plain film, bone scan, and MRI within a 1‐month interval between February 2008 and December 2012. The findings in plain film, the extent of increased uptake in bone scan, and signal change in MRI were compared to evaluate the actual level of pain. All patients received percutaneous vertebroplasty according to MR finding. Pain scores (visual analog scale) of the study patients were compared prior to and after the procedure. Results A total of 52 patients with a mean age of 79.1 years (range 59–92 years) were enrolled in this study, and were treated by vertebroplasty confirmed by MRI. It was observed that patient pain score (visual analog scale) improved from 7.6 to 2.8. Plain film examination revealed 79 vertebrae that were suspected to be compression fractures. Among the suspected vertebrae, 62 showed increased uptake in bone scan, and MRI showed bony edema change in 58 vertebrae. The consistency between bone scan and MRI was 96.9% in patients with single‐level suspected fracture on plain film. There was moderate agreement (kappa was 0.56) in patients where multiple levels were noted. Fifteen vertebrae with vacuum cleft sign on plain film showed total concordance in both bone scan and MRI. Conclusion For patients with single‐level compression fracture, the painful level in osteoporotic vertebral fractures can be determined by plain film and bone scan testing. Vacuum cleft sign noted on plain film may be enough to localize the level of pain. However, MRI testing is further needed in multiple osteoporotic vertebral fracture patients.

Fluid-induced, shear stress-regulated extracellular matrix and matrix metalloproteinase genes expression on human annulus fibrosus cells.

BackgroundMechanical loading plays an important role in the regulation of extracellular matrix (ECM) homeostasis as well as pathogenesis of intervertebral disc (IVD) degeneration. The human annulus fibrosus (hAF) in the IVD is subjected to contact shear stress during body motion. However, the effects of shear stress on hAF cells remain unclear. This aim of the study was to investigate the expression of the ECM (COLI, COLIII and aggrecan) and matrix metalloproteinase (MMP-1, MMP-3 and ADAMTS-4) genes in hAF cells following fluid-induced shear stress in a custom-fabricated bio-microfluidic device.MethodshAF cells were harvested from degenerated disc tissues in routine spine surgery, staged by magnetic resonance imaging, expanded in monolayers and then seeded onto the bio-microfluidic device. The experimental groups were subjected to 1 and 10 dyne/cm2 shear stress for 4 h, and no shear stress was applied to the control group. We used real time polymerase chain reaction for gene expression.ResultsShear stress of 1 dyne/cm2 exerted an anabolic effect on COLI and COLIII genes and catabolic effects on the aggrecan gene, while 10 dyne/cm2 had an anabolic effect on the COLI gene and a catabolic effect on COLIII and aggrecan genes. The COLI gene was upregulated in a stress-dependent manner. Expression of MMP-1 was significantly higher in the 10 dyne/cm2 group compared to the control group (P < 0.05), but was similar in the control and 1 dyne/cm2 groups. Expression of MMP-3 and ADAMTS-4 were similar in all three groups.ConclusionTaken together, hAF cells responded to shear stress. The findings help us understand and clarify the effects of shear stress on IVD degeneration as well as the development of a new therapeutic strategy for IVD degeneration.

Staged protocol for the treatment of chronic femoral shaft osteomyelitis with Ilizarov's technique followed by the use of intramedullary locked nail

Background Infected nonunion of the femoral shaft is uncommon, and usually presents with challenging therapeutic and reconstructive problems. There are still controversies over treating infected nonunion of the femoral shaft. The purposes of this retrospective study were to review the treatment outcomes and describe a staged protocol for spontaneous wound healing. Methods Six patients with chronic femoral shaft infected‐nonunion from October 2002 to September 2010 were included in this retrospective study. Serial plain films and triple films of lower legs were performed to evaluate the alignment of the treated femoral shaft and bony union following our staged protocol of Ilizarov distraction osteogenesis and intramedullary nailing. Results An average bone defect of 7 cm was noted after staged osteotomy. Mean follow‐up was 87.5 (range, 38–133) months. Union was achieved in all six patients, with an average external fixation time of 6.8 (range, 5–11) months. There was no reinfection. One complication of a 4‐cm leg discrepancy was noted, with an initial shortening of 15 cm. The mean knee ranges of motion (ROM) before staged protocols and at final follow‐up were 64.2 ± 8.6 (range, 60–75)° and 53.3 ± 9.3 (range, 40–65)°, respectively. The ROM at the knee joint statistically decreased following staged protocols. Conclusion In the treatment of chronic femur osteomyelitis, the staged protocol of Ilizarov distraction osteogenesis followed by intramedullary nailing was safe and successful, and allowed for union, realignment, reorientation, and leg‐length restoration. With regard to the soft tissue, this technique provides a unique type of reconstructive closure for infected wounds. It is suggested that the staged protocol is reliable in providing successful simultaneous reconstruction for bone and soft tissue defects without flap coverage.

Development of a two-step protocol for culture expansion of human annulus fibrosus cells with TGF-β1 and FGF-2

BackgroundDifferent biologic approaches to treat disc regeneration, including growth factors (GFs) application, are currently under investigation. Human annulus fibrosus (hAF) repair or regeneration is one of the key elements for maintenance and restoration of nucleus pulposus function. However, so far there is no effective treatment for this purpose. The aim of the present study was to investigate the response of hAF cells to different combinations of GFs, and develop a protocol for efficient culture expansion.MethodshAF cells were harvested from degenerated disc tissues during surgical intervertebral disc removal, and hAF cells were expanded in a monolayer. The experiments were categorized based on different protocols with transforming growth factor (TGF-β1) and fibroblast growth factor (FGF-2) culture for 14 days: group 1 had no GFs (control group); group 2 received TGF-β1; group 3 received FGF-2; group 4 received both GFs; and group 5 (two-step) received both GFs for the first 10 days and TGF-β1 only for the next 4 days. Cell proliferation, collagen, and noncollagen extracellular matrix (ECM) production and genes expression were compared among these groups.ResultsAt days 3, 7 and 10 of cultivation, groups 4 and 5 had significantly more cell numbers and faster cell proliferation rates than groups 1, 2, and 3. At 14 days of cultivation, significantly more cell numbers were observed in groups 3 and 4 than in group 5. The group 4 had the most cell numbers and the fastest proliferation rate at 14 days of cultivation. After normalization for cell numbers, group 5 (two-step) produced the most collagen and noncollagen ECM at 10 and 14 days of cultivation among the five groups. In group 5, ECM gene expression was significantly upregulated. High expression of matrix metalloproteinase-1 was upregulated with FGF-2 on the different days as compared to the other groups. Annulus fibrosus cell phenotypes were only marginally retained under the different protocols based on quantitative polymerase chain reaction results.ConclusionTaken together, the two-step protocol was the most efficient among these different protocols with the most abundant ECM production after normalization for cell numbers for culture expansion of hAF cells. The protocol may be useful in further cell therapy and tissue engineering approaches for disc regeneration.

Anterior release may not be necessary for idiopathic scoliosis with a large curve of more than 75° and a flexibility of less than 25%

BACKGROUND CONTEXT To improve correction and fusion rates, an anterior release is often needed for the treatment of idiopathic scoliosis with a curve of more than 75° before posterior correction, instrumentation, and fusion. However, there are disadvantages to anterior release, and we are concerned about whether it is necessary for anterior-posterior spinal fusion in these patients. PURPOSE The objective of this study was to compare the surgical results for idiopathic scoliosis with a curve of more than 75° and a flexibility of less than 25% between using posterior-only approach and combined anterior release followed by posterior correction with a hybrid construct (hooks and pedicle screws) and spinal fusion. STUDY DESIGN/SETTING This was a retrospective cohort study. PATIENT SAMPLE From 2000 to 2014, 388 consecutive patients with idiopathic scoliosis were treated surgically at our hospital. Of these patients, 53 whose primary curves were more than 75° with a flexibility of less than 25%, at an incidence of 13.6%, were included and divided into two groups. Thirty-one patients (mean age: 16.3 years old) who underwent anterior release followed by posterior correction, instrumentation, and fusion were included in the A+P group, and the remaining 22 patients (mean age: 17.3 years old) were designated as the P group for posterior procedure alone. OUTCOME MEASURES The clinical outcomes were analyzed in terms of correction and loss of correction and by the Scoliosis Patient Questionnaire: Version 30 functional questionnaire. MATERIALS AND METHODS In the A+P group, halo-femoral traction was applied for 1 week between the anterior release and the posterior procedure. Posterior instrumentation with a hybrid construct with hooks and pedicle screws was used for both groups. The radiological and functional outcomes were compared between the two groups. RESULTS The average preoperative Cobb angle was 85.3° for the A+P group, with an average 17.4% flexibility, and 80° for the P group, with 15.3% flexibility. The postoperative Cobb angle was 53.1° for the A+P group and 45.6° for the P group. The Cobb angle at the final follow-up for the A+P group was 55.2° and that for the P group was 48°. The average correction rates of the A+P and P groups were 37% and 43.4%, respectively. There were no statistically significant differences between the groups in gender, age, number of levels fused, and flexibility of coronal curve. With a minimum 2-year follow-up, similar results were found between these two groups in terms of correction rate, loss of correction, and functional outcome. CONCLUSIONS In this study, we found that a posterior-only approach with hybrid construct (hooks and pedicle screws) could provide a correction similar to that of an anterior-posterior approach. Also, the disadvantages of anterior release could be avoided by the posterior-only approach.