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Previous studies of patient positioning during spinal surgery evaluated intraoperative or immediate postoperative outcomes after short-instrumented lumbar fusion. However, patient positioning during long-instrumented fusion for an adult spinal deformity (ASD) might be associated with differences in intraoperative parameters such as blood loss and longer-term outcomes such as spine alignment, and comparing types of surgical tables in the context of these larger procedures and evaluating longer-term outcome scores seem important.(1) Do blood loss and the number of transfusions differ between patients who underwent multi-level spinal fusion with a Wilson frame and those with a four-poster frame? (2) Does restoration of lumbar lordosis and the sagittal vertical axis differ between patients who underwent surgery with the use of one frame or the other? (3) Do clinical outcomes as determined by Numeric Rating Scale and Oswestry Disability Index scores differ between the two groups of patients? (4) Are there differences in postoperative complications between the two groups?Among 651 patients undergoing thoracolumbar instrumented fusion between 2015 and 2018, 129 patients treated with more than four levels of initial fusion for an ASD were identified. A total of 48% (62 of 129) were eligible; 44% (57 of 129) were excluded because of a history of fusion, three-column osteotomy, or surgical indications other than degenerative deformity, and another 8% (10 of 129) were lost before the minimum 2-year follow-up period. Before January 2017, one surgeon in this study used only a Wilson frame; starting in January 2017, the same surgeon consistently used a four-poster frame. Forty patients had spinal fusion using the Wilson frame; 85% (34 of 40) of these had follow-up at least 2 years postoperatively (mean 44 ± 13 months). Thirty-two patients underwent surgery using the four-poster frame; 88% (28 of 32) of these were available for follow-up at least 2 years later (mean 34 ± 6 months). The groups did not differ in terms of age, gender, BMI, type of deformity, or number of fused levels. Surgical parameters such as blood loss and the total amount of blood transfused were compared between the two groups. Estimated blood loss was measured by the amount of suction drainage and the amount of blood that soaked gauze. The decision to transfuse blood was based on intraoperative hemoglobin values, a protocol that was applied equally to both groups. Radiologic outcomes including sagittal parameters and clinical outcomes such as the Numerical Rating Scale score for back pain (range 0-10; minimal clinically important difference [MCID] 2.9) and leg pain (range 0-10; MCID 2.9) as well as the Oswestry Disability Index score (range 0-100; MCID 15.4) were also assessed through a longitudinally maintained database by two spine surgeons who participated in this study. Repeated-measures analysis of variance was used to compare selected radiologic outcomes between the two groups over time.Blood loss and the total amount of transfused blood were greater in the Wilson frame group than in the four-poster frame group (2019 ± 1213 mL versus 1171 ± 875 mL; mean difference 848 [95% CI 297 to 1399]; p = 0.003 for blood loss; 1706 ± 1003 mL versus 911 ± 651 mL; mean difference 795 [95% CI 353 to 1237]; p = 0.001 for transfusion). Lumbar lordosis and the sagittal vertical axis were less restored in the Wilson frame group than in the four-poster frame group (7° ± 10° versus 18° ± 14°; mean difference -11° [95% -17° to -5°]; p0.001 for lumbar lordosis; -22 ± 31 mm versus -43 ± 27 mm; mean difference 21 [95% CI 5 to 36]; p = 0.009 for the sagittal vertical axis). Such differences persisted at 2 years of follow-up. The proportion of patients with the desired correction was also greater in the four-poster frame group than in the Wilson frame group immediately postoperatively and at 2 years of follow-up (50% versus 21%, respectively; odds ratio 3.9 [95% CI 1.3 to 11.7]; p = 0.02; 43% versus 12%, respectively; odds ratio 5.6 [95% CI 1.6 to 20.3]; p = 0.005). We found no clinically important differences in postoperative patient-reported outcomes including Numeric Rating Scale and Oswestry Disability Index scores, and there were no differences in postoperative complications at 2 years of follow-up.The ideal patient position during surgery for an ASD should decrease intra-abdominal pressure and induce lordosis as the abdomen hangs freely and hip flexion is decreased. The four-poster frame appears advantageous for long-segment fusions for spinal deformities. Future studies are needed to extend our analyses to different types of spinal deformities and validate radiologic and clinical outcomes with follow-up for more than 2 years.III, therapeutic study.

STUDY DESIGN A retrospective study. OBJECTIVE The aim of this study was to investigate proximal junctional kyphosis (PJK) after lumbosacral long fusion according to preoperative Roussouly and lumbar degenerative kyphosis (LDK) types. SUMMARY OF BACKGROUND DATA Although previous studies have suggested some risk factors for PJK, the effects of preoperative grade of sagittal imbalance and paraspinal muscles degeneration on PJK remain unclear. METHODS Eighty-seven patients who had undergone lumbosacral fusion more than five levels with available clinical and radiological data were enrolled. The presence of PJK defined as sagittal Cobb angle ≥20° between the uppermost instrumented vertebra (UIV) and two supra-adjacent vertebrae at postoperative 2-year radiographs was recorded. Its occurrence was compared according to preoperative Roussouly and LDK types (Takemistu type) and the degree of paraspinal muscle degeneration at the upper level of UIV. Other sagittal radiographic parameters were also measured. RESULTS In this series, 28 patients (group I, 32.2%) showed radiological PJK, whereas 59 patients did not show radiological PJK (non-PJK patients, group II, 67.8%) at postoperative 2 years. PJK presented more prevalence in type III and type IV of LDK types (26/27, 96.3%). However, Roussouly types did not show any significant difference in PJK prevalence. In radiological parameters, a larger preoperative SVA (P = 0.018) and PI-LL (P = 0.015) were associated with PJK. Also, smaller quantity and lower quality of paraspinal muscles at T12-L1 level showed significant (P

Study design This was a retrospective comparative study. Objective The main objective of this article was to evaluate the clinical and radiologic efficacies of minimally invasive lateral lumbar interbody fusion (LLIF) for clinical adjacent segment pathology (ASP). Summary of background data Minimally invasive techniques have been increasingly applied for spinal surgery. No report has compared LLIF with conventional posterior lumbar interbody fusion for clinical ASP. Methods Forty patients undergoing LLIF with posterior fusion (hybrid surgery) were compared with 40 patients undergoing conventional posterior lumbar interbody fusion (posterior surgery). The radiologic outcomes including indirect decompression in hybrid surgery group, and clinical outcomes such as the Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) were assessed. Postoperative major complications and reoperations were also compared between the 2 groups. Results Correction of coronal Cobb's angle and segmental lordosis in the hybrid surgery were significantly greater postoperatively (2.8 vs. 0.9 degrees, P=0.012; 7.4 vs. 2.5 degrees, P=0.009) and at the last follow-up (2.4 vs. 0.5 degrees, P=0.026; 4.8 vs. 0.8 degrees, P=0.016) compared with posterior surgery. As regards indirect decompression of the LLIF, significant increases in thecal sac (83.4 vs. 113.8 mm) and foraminal height (17.8 vs. 20.9 mm) were noted on postoperative magnetic resonance imaging. Although postoperative back VAS (4.1 vs. 5.6, P=0.011) and ODI (48.9% vs. 59.6%, P=0.007) were significantly better in hybrid surgery, clinical outcomes at the last follow-up were similar. Moreover, intraoperative endplate fractures developed in 17.7% and lower leg symptoms occurred in 30.0% of patients undergoing hybrid surgery. Conclusions Hybrid surgery for clinical ASP has advantages of segmental coronal and sagittal correction, and indirect decompression compared with conventional posterior surgery. However, LLIF-related complications such as endplate fracture and lower leg symptoms also developed. LLIF should be performed considering advantages and approach-related complications for the clinical ASP.

Study design In vitro experimental study. Objective To investigate the impact of increased osteoblastic activity on the proliferation and survival of multiple myeloma (MM) plasma cells in vitro SUMMARY OF BACKGROUND DATA.: MM is one of representative hematologic malignancies that cause skeletal-related events (SREs) and dysregulation of bone remodeling is known as a key pathomechanism of disease progression and skeletal-related events. However, decreased proliferation of MM at fracture sites is frequently noted in clinical situations regardless of systemic disease activity. Methods Co-culture under various conditions was used to investigate effects of increased osteoblastic activity on survival and proliferation of MM plasma cells. MM plasma cells were cultured in culture media (control) and co-cultured with human mesenchymal stem cells (hMSCs, group I), osteoblasts (OBs) induced from hMSCs (group II) or bone morphogenic protein-2 (BMP-2, group III). Proliferation measured as extracellular signal-regulated kinase (ERK) and immunoglobulin G (Ig G) expression and apoptosis measured as fluorescence-activated cell sorting (FACS) with annexin V method, caspase-3, and stat-3 expression were assessed for cultured MM plasma cells, along with expression of sclerostin. Results After 72 hours of co-culture, group II and III showed decreased ERK expression compared with controls. Lower Ig G expression was also noted for groups II and III compared with controls. Group I did not show significantly decreased Ig G and ERK expression compared with controls. Expressions of caspase-3 in groups II and III were higher than controls. Co-culture with hMSCs showed decreased caspase-3 expression compared with control. FACS with annexin V showed higher apoptosis in groups II and III. Sclerostin expression was also decreased in osteoblastic conditions compared with the control and hMSCs co-culture condition. Conclusion Collectively, our data suggest that increased osteoblastic conditions may provide not only prevention of SREs but also anti-tumor effects on MM cells in the bone marrow environment. Level of evidence N/A.

A retrospective cohort study.To evaluate the clinical and radiological efficacies of supplementing minimally invasive lateral lumbar interbody fusion (LLIF) with open posterior spinal fusion (PSF) in adult spinal deformity (ASD).Minimally invasive techniques have been increasingly applied for surgery of ASD. Few reports have been published that directly compare LLIF combined with PSF to conventional PSF for ASD.To evaluate the advantages of minimally invasive LLIF for ASD, patients who underwent minimally invasive LLIF followed by open PSF (combined group) were compared with patients who only underwent PSF (only PSF group). The clinical and radiological outcomes for deformity correction and indirect decompression were assessed. The occurrence of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) were also evaluated.No significant differences were observed in the clinical outcomes of the Oswestry Disability Index (ODI), visual analog scale, and major complications including reoperations between the groups. No additional advantage was found for coronal deformity correction, but the restoration of lumbar lordosis in the combined group was significantly higher postoperatively (15.3° vs. 8.87°, P = 0.003) and last follow-up (6.69° vs. 1.02°, P = 0.029) compared to that of the only PSF group. In the subgroup analysis for indirect decompression for the combined group, a significant increase of canal area (104 vs. 122 mm) and foraminal height (16.2 vs. 18.5 mm) was noted. The occurrence of PJK or PJF was significantly higher in the combined group than in the only PSF group (P = 0.039).LLIF has advantages of indirect decompression and greater improvements of sagittal correction compared to only posterior surgery. LLIF should be conducted considering the above-mentioned benefits and complications including PJK or PJF in ASD.4.

STUDY DESIGN Animal experimental study OBJECTIVES.: The purpose of this study is to investigate the effects of extracorporeal shock waves (ESWs) on endogenous neural stem cells (NSCs) proliferation after spinal cord injury (SCI). SUMMARY OF BACKGROUND DATA Exogenous stem cell transplantation for SCI still has many limitations to be addressed such as ideal cell sources, timing of transplantation, and fate of the transplanted cells. Moreover, the efficacy is another issue owing to a peculiar pathologic condition in the chronic phase of SCI. METHODS Contusive SCI was made using 24 Sprague-Dawley rats, and ESWs were applied at post-injury 4 weeks in rats. Proliferation and differentiation of endogenous NSCs (DCX, Sox-2) and axonal sprouting (GAP-43 and MAP-2) were observed at 6 weeks after application of ESWs. Differentiation of the activated neural stem cells was also investigated by coexpression of neuronal/glial cell markers (GFAP, Neu N, and CC-1). Immunofluorescence staining and western blotting were performed for quantitative analysis, and these results were compared with those in the control group. For clinical assessment, the BBB locomotor rating scale was performed. RESULTS More proliferation of endogenous neural stem cells was noted in the experimental groups, and these activated cells were mainly founded in the ependymal layer of the central canal and the injured posterior horn. Differentiation into neuronal and glial cells was also noted in a limited number of cells. With respect to axonal regeneration, GAP-43 and MAP-2 expressions in the experimental groups were also significantly higher than those in the control group. During 6 weeks' clinical observation following ESWs application, functional improvement of the hindlimb was observed without clinical deterioration by trials. CONCLUSION Collectively, these findings indicate that ESWs on the chronic phase of SCI induce activation of endogenous NSCs and consequent functional improvement. LEVEL OF EVIDENCE N/A.

Study design A case report and literature review. Objective To report a late dislocation of the vertebra caused by progressive dural ectasia combined with type-1 neurofibromatosis (NF-1) and the clinical results of pseudarthrosis repairs using autologous cultured osteoblasts. Summary of background data NF-1 is a well-known genetic disorder that is commonly characterized by spinal deformities including kyphoscoliosis. Late dislocation of the vertebra resulting from progressive dural ectasia after surgical correction of NF-1 scoliosis is a very rare occurrence, and pseudarthrosis frequently develops after surgical intervention for this complex spinal deformity. Methods A 32-year-old female patient with NF-1 scoliosis underwent surgical correction with posterior instrumented fusion. Seventeen years later, dislocation of the lumbar spine with implant failure resulting from massive progressive dural ectasia was observed. She underwent anterior interbody fusion three times and posterior instrumented fusion four times for pseudarthrosis followed by surgical deformity correction. For the last operation, autologous cultured osteoblasts were used as a therapeutic approach to repair the pseudarthrosis, and a three-dimensional printing technique was used to understand the surgical anatomy of the dislocated lumbar spine in detail. Results After the final operation, bone union was achieved and confirmed by clinical and radiological examination. Conclusion Spine surgeons should be knowledgeable about the possibility of late destabilization of the spine, due to pulsatile dural ectasia, and a high rate of pseudarthrosis in neurofibromatosis. Autologous cultured osteoblasts may prove to be a modality that can be applied pseudarthrosis repair to treat complex spinal deformity. Level of evidence 5.

Animal experimental study.To present experimental evidence for cell therapy for spinal cord injury (SCI).In chronic SCI, the efficacy of cell engraftment has been known to be low due to its distinct pathology. Alteration of microenvironment was tried using extracorporeal shock waves (ESW) for chronic SCI, and the efficacy of cell therapy was investigated.A chronic contusive SCI model was made in 36 Sprague-Dawley rats. The rats were allocated into (1) control group (SCI only), (2) ESW control group (SCI + ESW), (3) IV group (SCI + intravenous transplantation of mesenchymal stem cells; MSCs), and (4) ESW + IV group (SCI + MSCs IV transplantation after ESW). ESW were applied at the energy determined by our preliminary trials. Engraftment of the cells and expressions of growth factors (brain-derived neurotrophic factor, neuronal growth factor) and cytokines (SDF-1, CXCR4, VEGF) at the epicenter were assessed. The Basso, Beattie, and Bresnahan locomotor scale was used for the clinical assessment.The mean numbers of engrafted cells were higher in the ESW+ IV than that in the IV with a statistical significance. The expression of SDF-1 was higher in the ESW groups than that in the control or IV group. CXCR4 was highly expressed in the transplanted groups. The expressions of growth factors in the treated group were higher in the treated group than those in the control group. However, various statistical significances were noted. The improvement of locomotor was higher in the transplanted groups than that in the control and ESW only group.At a given energy level, ESW presented more engraftment of the transplanted MSCs without any clinical deterioration in a chronic SCI. Based on this promising result and possible explanations, ESW may cause an alteration of the microenvironment for the cell therapy in chronic SCI.N/A.

Study design Retrospective cohort study. Objective To investigate the fate of sclerosis and anterior osteophytes in the fused segments after instrumented lumbar fusion for degenerative lumbar disorders. Summary of background data Sclerosis and osteophytosis are well-known radiographical findings, but little is known of their significance with regard to spontaneous resorption after spine fusion. Methods Thirty patients (9 males, 21 females; 60 vertebra; mean age of 66.9 yr [45-86 yr]) were divided into a posterolateral fusion group (n = 14, 28 vertebrae) and a posterior lumbar interbody fusion group (n = 16, 32 vertebrae). Using serial radiographs obtained preoperatively; postoperatively at 3, 6, 12, and 24 months; and last follow-up, sclerotic areas of each involved vertebra were mapped and osteophyte lengths were measured. Results Sclerosis and osteophytes decreased with time for the instrumented fusion. The decrease in sclerotic areas and osteophytes length was observed as early as 3 months postoperatively, and the significant changes between each time point were noted in initial 3- and 6-month intervals. In terms of the type of surgery, similar changes were noted in the posterolateral fusion and posterior lumbar interbody fusion groups. Conclusion Resorption of osteophytes and sclerosis after instrumented spine fusion were observed. Significant resorption was noted at 3 and 6 months postoperatively. As well, most graft bone would be incorporated in postoperative 6 months. Resorption of osteophytes and sclerosis after instrumented spine fusion could be helpful to confirm the successful union. Level of evidence 4.

CASE A 73-year-old man with instrumented fusion of L3-4-5 underwent the removal of previous pedicle screws and posterior instrumented fusion of L1-2-3. The solid dorsal fusion mass of L3-5 was identified intraoperatively and preoperatively. At 3 years after the second surgery, he presented with abrupt radiating pain in the left leg. Plain radiographs showed a collapse of the intervertebral disc space, and magnetic resonance imaging showed disc herniation of L3-4. CONCLUSIONS Disc herniation even in solid fused segments may occur. Removal of pedicle screws and cranial extension of interbody fusion may increase the intradiscal stress associated with physiologic cantilever motion of the disc.

Study design Retrospective study. Objectives To investigate the clinical feasibility and outcomes from direct lateral interbody fusion (DLIF) using autogenous bone grafts and percutaneous posterior instrumentation (PPI) for infectious spondylitis. Summary of background data As one of the minimally invasive techniques, PPI has been attempted for various degenerative lumbar spine disorders combined with anterior lumbar interbody fusion or transforaminal lumbar interbody fusion. PPI has been played more roles recently as an internal fixation method for infectious spondylitis. However, the clinical outcomes of DLIF using an autogenous bone graft combined with PPI for infectious spondylitis have been rarely reported. Materials and methods Sixteen patients (mean age, 60.3 ± 18.8 y) who suffered from pyogenic spondylitis underwent single-stage DLIF using an autogenous iliac bone graft combined with PPI. Clinical and radiologic outcomes were evaluated by visual analog scale (VAS), Oswestry Disability Index (ODI), and eradication of primary disease. Radiologic outcomes were evaluated by changes of affected segmental lordosis and fusion status. Results Bony fusion and eradication of primary disease were obtained in all patient except 1 case during the follow-up (mean, 31.3 ± 13.1 mo; range 14-46 mo). Preoperative VAS (7 ± 1.2) and ODI (61.3 ± 5.4) scores improved significantly at the last follow-up (VAS, 3.4 ± 1.5; ODI, 32.3 ± 15.4). C-reactive protein normalized at postoperative 20.1 ± 0.7 days (range, 15-28 d). Although height and lordosis in the affected segment were restored by surgery, all patients showed loss of the restored lordosis and height at the final follow-up. Loss of the restored lordosis and height were related to subsidence of the grafted bone. Conclusions Minimally invasive PPI followed by debridement and DLIF was a feasible surgical alternative in our consecutive 16 cases of pyogenic spondylitis. In most cases, however the subsidence of anteriorly grafted fusion was inevitable despite successful fusion and eradication of the primary lesion.

Study design Retrospective cohort study. Objective To identify the effect of cement augmentation for cephalad vertebral fracture after instrumented lumbar fusion. Summary of background data Osteoporosis may contribute to cephalad vertebral fractures by an altered biomechanics in the adjacent segments due to the loss of motion at the fused segments. However, few studies on the treatment for cephalad fractures using bone cement augmentation after instrumented lumbar fusion have been published. Methods Seventeen patients who had cephalad vertebral fractures after instrumented lumbar fusion underwent percutaneous vertebroplasty (PVP). All patients were divided into 2 groups according to the presence of intravertebral vacuum clefts (IVC) on plain radiographs and magnetic resonance imaging: group 1 consisted of 9 patients without an associated IVC and group 2 consisted of 8 patients with an IVC. The Oswestry Disability Index and the Visual Analogue Scale were recorded prospectively. The radiologic parameters of kyphotic deformity, vertebral height changes, and leakage of cement were studied. Results The Oswestry Disability Index and Visual Analogue Scale scores in group 1 decreased after PVP, but the mean score in group 2 was higher than in group 1 at the last follow-up. The mean kyphosis measured 15.7±7.4 degrees preoperatively and 15.6±7.1 degrees at the final follow-up in group 1, and 16.9±8.8 degrees preoperatively and 27.2±8.8 degrees at the final follow-up in group 2.The mean preoperative anterior and posterior vertebral height ratio measured 0.6±0.2 preoperatively and 0.6±0.2 at the final follow-up in group 1, and 0.6±0.2 preoperatively and 0.5±0.2 at the final follow-up in group 2.The mean preoperative middle and posterior vertebral height ratio measured 0.5±0.1 preoperatively and 0.6±0.1 at the final follow-up in group 1, and 0.5±0.1 preoperatively and 0.4±0.2 at the final follow-up in group 2. Four patients underwent revision surgery in group 2 and 1 in group 1. Conclusions Although PVP treatment may be a useful method for cephalad vertebral fractures after instrumented lumbar fusion in elderly patients with persistent unremitting back pain, recollapse of the vertebral body can occur after a PVP for cephalad or adjacent vertebral fractures with an IVC.

Study design An experimental comparative study on moderate epidural hypothermia (MEH) versus moderate systemic hypothermia (MSH) after spinal cord injury (SCI). Objective To compare neuroprotective effects of hypothermia between MEH and MSH after SCI in rats. Summary of background data Experimental MEH or MSH has been attempted for neuroprotection after ischemic or traumatic SCI. However, there is no comparative study on neuroprotective effect of MEH and MSH after SCI. If hypothermia is to be considered as 1 modality for treating SCI, further studies on the advantages and disadvantages of hypothermia will be mandatory. Methods A spinal cord contusion was produced in all 32 rats, and these rats were randomly divided into 4 groups-8 rats in each group: (1) the control group (spinal cord contusion only), (2) the methylprednisolone group, (3) the MEH group (28°C for 48 hr), and (4) the MSH group (32°C for 48 hr). The functional recovery was assessed using Basso, Beattie, Bresnahan scale and antiapoptotic and anti-inflammatory effects were assessed. Results The Basso, Beattie, Bresnahan scale scores in both the hypothermia groups were significantly higher than that in the control group at 6 weeks. The numbers of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells and OX-42 positive cells were significantly lower in both the MEH and MSH groups than that in the control group. The p38 mitogen-activated protein kinases expression of the treated groups was significantly lower than that of the control group. The expression of caspase-8 and caspase-9 significantly decreased in the treated groups compared with that of the control group. However, in terms of caspase-3, only the MSH group has shown to be significantly lower than that of the control group. Conclusion This study presented that both systemic and epidural hypothermia demonstrated neuroprotective effects after SCI. Systemic hypothermia showed more neuroprotective effect by antiapoptotic and anti-inflammatory effects.

Study design A case report and literature review. Objective To illustrate the spontaneous resolution of unstable pathological fracture of the odontoid process of the C2 caused by Langerhans cell histiocytosis (LCH) in early childhood. Summary of background data The involvement of atlantoaxial LCH is very rare and its treatment is unfamiliar to surgeons. Therefore, the management of pediatric LCH of the odontoid process and the C2 body is challenging and must be adapted according to the patient's needs; it could range from observation to surgical intervention. Methods A case of pathological fracture of the odontoid process with torticollis diagnosed with LCH of the odontoid process and C2 body and involving right femur in early childhood is presented. A histopathological study showed LCH. The patient underwent brace immobilization and systemic chemotherapy. Results The patient showed successful bony remodeling without LCH recurrence on CT. The neck pain was resolved, and there was no limitation in neck movement. Conclusion Immobilization and systemic chemotherapy with close observation are adequate for the management of patients despite the unstable pathological fracture of the odontoid process.

Rationale Traumatic bilateral facet dislocation in the lumbar (L) spine has rarely been reported. All reported cases were presented with acute facet dislocation. However, we present the first case of delayed bilateral facet dislocation at L4-5. Patient concerns A 34-year-old woman presented with back pain after a head-on collision. The patient was treated conservatively for 3 months with rigid orthosis and activity restriction. Even after this conservative treatment, she continued to suffer from persistent back pain that radiated down her left leg and a progressively kyphotic posture. Diagnoses Initial imaging studies revealed a fracture of the left L5 superior articular process with a posterior ligament complex (PLC) injury. Subsequent radiographs showed the locked facet dislocation with kyphotic changes. Interventions The patient underwent surgical reduction and fusion, and the operative findings revealed the L4-5 bilateral facet dislocation and rupture of the PLC at the index level. Outcomes After surgical reduction and fusion at L4-5 by posterior interbody fusion, we achieved a satisfactory clinical outcome. Lessons Injury of the PLC in the lower lumbar region deserves careful attention for the development of sequelae. The anatomic transition from lordosis to kyphosis, in the lumbosacral region may be related to this type of injury.

A retrospective clinical study.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.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.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.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 (P0.05), but it decreased significantly by 3 months after surgery (P0.05). In Groups I and II, intervertebral height correction was maintained until 1 month after surgery (P0.05), but by 3 months after surgery, it had collapsed significantly (P0.05). 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.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.

STUDY DESIGN: Human intervertebral disc was obtained for the study of hypoxia inducible factor (HIF)-1alpha and apoptosis using immunohistochemical staining. OBJECTIVE: To study the expression of HIF-1alpha and apoptosis in herniated lumbar discs. SUMMARY OF BACKGROUND DATA: The presence of HIF-1alpha in human chondrocytes and rat intervertebral discs has been proven; however, to our knowledge, its expression in human intervertebral disc cells has not been reported. Apoptosis of the human intervertebral disc appears as a degenerative change caused by the aging of the intervertebral disc. To our knowledge, there is no reported study showing the correlation between apoptosis and HIF-1alpha in the human intervertebral disc. METHODS: There were 15 human intervertebral discs stained for HIF-1alpha immunohistochemically, and apoptosis was detected using the terminal deoxynucleotidyl transferase mediated-dUTP nick end labeling method. On average, the patients were 32.9 years old. The intervertebral discs were divided into noncontained (9 patients) and contained (6) groups. For the control group, 5 disc samples were used. RESULTS: The expression of HIF-1alpha was visualized in every case, with an average of 62.2% +/- 9.5% in the noncontained group, 30.5% +/- 3.6% in the contained group, and 11.4% +/- 9.3% in the control group. Apoptosis occurred in 74.3% +/- 7.3% of the cells in the noncontained group, 42.8% +/- 5.5% of the cells in the contained group, and 28% +/- 8.4% of the cells in the control group. HIF-1alpha and apoptosis expressions were both observed more frequently in the noncontained disc herniation group (P < 0.001). The correlation analysis between the degree of HIF-1alpha expression and apoptosis was also statistically significant. CONCLUSIONS: HIF-1alpha and apoptosis physiologically occur in human beings. Their expression was the highest in the noncontained group. HIF-1alpha may play a crucial role for the survival of disc cells and resorption of the herniated disc in human intervertebral discs.

STUDY DESIGN Immunohistochemistry and in situ nick end-labeling (TUNEL) were performed in rat lumbar intervertebral discs. OBJECTIVES To demonstrate the mechanism of notochordal cell death in the nucleus pulposus (NP). SUMMARY OF BACKGROUND DATA With age, notochordal cells gradually disappear in the NP. We hypothesized that this phenomenon might be related to Fas-mediated apoptosis. MATERIALS AND METHODS Expressions of Fas; Fas ligand (FasL); caspase 3, 8, 9, 10; Ki-67 protein; and TUNEL were examined in 4-week-, 6-month- and 12-month-old rat NPs. Apoptosis (TUNEL-positive) and proliferation potential (Ki-67-positive) indexes of notochordal cells were calculated and compared among age groups. RESULTS Notochordal cells constitutively expressed both Fas and FasL. Among their downstream initiator (caspase 8, 9, and 10) and executioner (caspase 3) caspases tested, caspase 9 and 3 were expressed. Proliferation potential of the notochordal cells was the highest at 4 weeks (1.96 +/- 1.3%) and decreased to a significantly lower level at 6 (0.81 +/- 0.68%) and 12 months (0.8 +/- 0.37%; P = 0.03 and 0.01, respectively). In contrast, apoptosis of the notochordal cells was the lowest at 4 weeks (3.52 +/- 1.07%) and increased to a significantly higher level at 6 (19.38 +/- 10.99%) and 12 months (21.51 +/- 16.99%; P < 0.001 in both comparisons). CONCLUSIONS Fas-mediated mitochondrial caspase 9 pathway is constitutively present in the rat notochordal cells. The constitutive expression of Fas, FasL and its downstream caspases, as well as the homogeneity ofnotochordal cell population suggests an autocrine or paracrine Fas-mediated counterattack to be a potential mechanism for apoptosis of rat notochordal cells. A regulated negative balance of notochordal cell proliferation against apoptosis is likely to involve the disappearance of notochordal cells in the rat NP. This information on the mechanism for apoptosis of notochordal cells could be important in the investigation of intervertebral disc development as well as aging and perhaps degeneration.

Immunohistochemistry was performed in organ-cultured intact and cartilage endplate (CE)-fractured rat intervertebral discs (IVDs).To demonstrate biologic events associated with migration of chondrocytes from hyaline CE into nucleus pulposus (NP).It was recently revealed that the transition from a notochordal NP to a fibrocartilaginous NP in the rabbit IVD is accomplished exogenously by chondrocytes migrating from CEs into the NP. This observation has not been studied in other animal models, and the biologic events associated with chondrocyte migration have not been elucidated in the literature.IVDs including cranial and caudal CEs were obtained from 4-week, 6-month, 12-month, and 18-month old Wistar rats. To accelerate chondrocyte migration, CEs of IVDs were fractured and cultured for 48 hours. IVDs without CE-fracture were used as a control for each age group. Expressions of membrane-type I matrix metalloproteinase (MT1-MMP, as a marker for cell migration and extracellular matrix digestion) and Ki-67 protein (as a proliferation marker) and pericellular deposition of type II collagen (as a marker for fibrocartilaginous matrix) by the chondrocytes migrating from CE into NP were examined immunohistochemically.In the control groups, chondrocyte migration limited only along the periphery of the notochordal NP and no chondrocytes were inside the NP proper. However, all the IVDs in the CE-fracture groups showed direct and more extensive migration of chondrocytes from CEs into the NP proper. The migrating chondrocytes in both control and CE-fracture groups expressed MT1-MMP and Ki-67 protein and deposited type II collagen in the NP.This report demonstrates the chondrocyte migration from CE into NP in the organ-cultured rat IVDs. This phenomenon is accelerated in the presence of CE fracture. The chondrocytes migrating from CEs into the NP expressed MT1-MMP and Ki-67 protein and deposited type II collagen. These biologic strategies probably enable chondrocytes of the hyaline CE to migrate into the ectopic NP region, replace notochordal cells, and change the notochordal tissue into fibrocartilage. These results suggest that similar biologic mechanisms may be involved in the natural transition from the notochordal NP to the fibrocartilaginous NP in other animal models, including human.

STUDY DESIGN Immunohistochemical study was done by harvesting articular cartilage of the facet joints during the decompressive surgery for spinal stenosis. OBJECTIVES To observe the expression of estrogen receptor on the articular cartilage of the facet joints in degenerative spondylolisthesis (DS) SUMMARY OF BACKGROUND DATA: Few attempts have been made to evaluate the effect of sex-hormone, although DS is more common in females than in males. METHODS After harvesting the articular cartilage of the facet joints in 17 DS and in 15 spinal stenosis (SS) patients, the expression of estrogen receptor and the severity of facet arthritis were observed by H-E and immunohistochemical staining, respectively. Measurements of both staining were made by using a semiquantitative analysis. RESULTS The significantly increased expression of estrogen receptor correlated with the severity of facet arthritis (r = 0.78, P < 0.05). There was a significantly increased expression of estrogen receptor of the facet joint in DS compared with SS (P < 0.01). The histologic-histochemical grading of cartilage lesion in DS was 12.4 (SEM, 0.6), which was significantly higher than in SS (P < 0.05). CONCLUSIONS These findings suggest that the higher expression of estrogen receptor might aggravate degenerative change of the facet articular cartilage and might also be considered one of the causative factors for DS in postmenopausal women.

Study design Bacterial adherence and biofilm formation in implant-associated infection may vary depending on species of microorganisms and characteristics of implant surfaces. Objectives We evaluated the differences in adherence and biofilm formation between Staphylococcus epidermidis and Mycobacterium tuberculosis on various spinal implant surfaces. Summary of background data In implant-associated infections, bacteria in biofilm are resistant to antibiotics or host defense mechanism. The removal of implants is usually necessary to eradicate infection. On the contrary, in tuberculous infection, complete debridement and antituberculous chemotherapy without removal of implant have been regarded as a safe procedure. Methods S. epidermidis and M. tuberculosis were cultured with 4 types of metal segments, smooth or rough-surfaced stainless steel, and titanium alloy, respectively. After isolation of colonized microorganisms and biofilm with trypsin treatment and culture on plate media, colony-forming units were counted. The features of adherence and biofilm formation were observed under scanning electron microscopy. Results Biofilm-forming S. epidermidis showed heavy adhesion and multiplication on the surface of all 4 metal segments, 16.5 times more colony-forming units than nonbiofilm-forming ones. On scanning electron microscopy, there were many aggregated microcolonies with thick biofilm in biofilm-forming S. epidermidis but much less in nonbiofilm-forming S. epidermidis. M. tuberculosis were rarely adhered to metal surfaces and showed scanty biofilm formation. Conclusions On the contrary to S. epidermidis, adherence and biofilm formation of M. tuberculosis on implant surface are less likely, and it can provide the basis of successful instrumentation in spine tuberculosis.

Sparganosis is a rare parasitic infection caused by the plerocercoid tapeworm larva of the genus Spirometra.We report the case of a 67-year-old man with a mass over the anteromedial surface of the proximal extremity of the tibia. We surgically excised a bursa containing Spirometra larvae.Sparganosis is a rare parasitic infection. We found no cases of lower extremity sparganosis combined with bursitis reported in the literature.Sparganosis should be considered in the differential diagnosis of soft tissue tumors, especially among patients who frequently have consumed mountain water or raw snakes or frogs.

Patients in whom good intertransverse fusion had been achieved were selected for the volumetric study of the fusion mass using sequential computed tomography scans.To assess the natural volumetric change of intertransverse fusion mass and the effect of the disease entity and spinal instrumentation on the fusion mass volume.The magnitude of volumetric change of the graft bone after intertransverse fusion is still inconclusive.Fifteen adult patients who underwent decompression surgery with single-level lumbar and lumbosacral intertransverse fusion were selected for this study. Preoperative diagnoses were degenerative spondylolisthesis in nine patients and isthmic spondylolisthesis in six. Seven of the 15 patients received pedicle screw fixation. They were categorized into two major groups: 1) instrumented and noninstrumented groups and 2) isthmic and degenerative groups. To assess the volumetric change of the graft bone, sequential computed tomography scans were obtained 2 weeks after surgery and again 18 months after surgery.The overall initial mean graft volume was 6251 mm3, which decreased to 2842 mm3 by 18 months after surgery (P0.001). The overall mean volume loss between the two periods was 54.8% of the initial graft volume. Although there was no significant difference in the mean graft volume between the groups at either 2 weeks or 18 months after surgery (P0.05 in all comparisons), the mean graft volume in each group decreased significantly during the observation period (P0.01 in all comparisons). There was no significant difference in the mean volume loss or in the ratio of residual volume to the initial graft volume between the groups during the study period (P0.05 in all comparisons). The initial graft volume correlated positively with the graft volume at 18 months after surgery (r = 0.612, P0.01) and volume loss (r = 0.949, P0.01), but negatively with the residual volume ratio (r = -0.507, P0.01).These results showed that more than one half of the initial graft bone volume was being absorbed during the consolidation processes of the graft bone, and that the volume loss during the period was not significantly affected by the spinal instrumentation or by the disease entity. It was also found that the greater the amount of the initial graft bone, the larger the fusion mass at 18 months after surgery. The volume loss, however, increased proportionally to an increase in the initial graft bone volume. The efficiency (ratio of residual volume to the initial graft volume) of the intertransverse fusion also tended to decline as the initial graft volume increased.

Sixty-seven patients were treated for Pott's paraplegia: 58 were adults and 9 were children. Sixty-four patients had active disease, and 3 had healed disease. All patients had triple chemotherapy with or without decompression surgery. Thirteen patients, including 9 children, were treated conservatively, whereas 54 patients who met the selection criteria for surgery were treated surgically. Fifty-two patients had anterior radical decompression surgery, and for 14 of them, anterior surgery was preceded by posterior instrumental stabilization surgery. Two patients with healed disease had posterior decompressive corpectomy. There was functional recovery in 60 (89.6%) patients, including 13 who had active disease that was treated conservatively. In 47 of the 54 surgically treated patients there was neurologic recovery, and 2 of these recovered incompletely with some residual spasticity. In the remaining 7 patients, there was no recovery. It took 2 to 6 months for recovery for the patients with conservative treatment, whereas it took

STUDY DESIGN A case report and review of the literature are presented. OBJECTIVE To describe an unusual simple bone cyst involving the pedicle of lumbar spine. SUMMARY OF BACKGROUND DATA To the authors' knowledge, only nine cases of a simple bone cyst involving the spine have been reported. Most of these reports have described mild back or neck pain because the presenting symptoms or cysts were found incidentally. In the reported case, acute severe back pain with radiating pain developed. Therefore, the study focus was on the unusual location, the presenting symptoms, and its spinal involvement. METHODS A cystic lesion involving the left pedicle of the first lumber vertebra was identified in a 53-year-old woman with sudden-onset severe back pain with pain radiating to the left leg. Surgical resection was undertaken along with review of the patient's medical record, imaging studies, microscopic findings of the lesion, and the related literature. RESULTS Microscopic examination of the cystic lesion corresponded with the findings of a simple bone cyst. A thin fibrous membrane with reactive bone formation was identified without evidence of hemorrhage. A favorable result was achieved by surgical resection. CONCLUSIONS This case study suggests that a simple bone cyst may be found in any portion of the spine, including the pedicle. Severe resting pain would be elicited by a pathologic fracture of the pedicle. Direct nerve compression by the fractured fragment and chemical irritation by cystic fluid would be compatible with the observed clinical manifestations.

STUDY DESIGN A case of bilateral pedicle stress fracture is reported, and the literature is reviewed. OBJECTIVES To report the rare case of bilateral pedicle stress fracture after instrumented posterolateral fusion, and to investigate the contributing factors. SUMMARY OF BACKGROUND DATA A 62-year-old man underwent revision spinal surgery for adjacent-segment degeneration. Decompression and instrumented posterolateral fusion from L1 to L3 were performed after removal of the previously inserted pedicular screws. In the patient's history, he had undergone L3-L5 instrumented posterolateral fusion for spinal stenosis 6 years previously. At 1 year after the revision surgery, he presented with severe progressive low back pain. Computer-assisted tomogram and bone scan demonstrated bilateral L4 pedicle stress fracture. To the best of the authors' knowledge, only two cases of pedicle stress fracture after lumbar posterolateral fusion have been reported. METHODS This study reviewed the reported patient's medical record, his imaging studies, and related literature. The possible factors contributing to bilateral pedicle stress fractures were investigated. RESULTS In the reported case, the features of radiographic studies confirmed bilateral pedicle stress fracture. The involved vertebra was L4. In all three cases reported so far, including the current case, the site of the pedicle stress fracture was at the junction of the pedicle and vertebral bodies. CONCLUSIONS Bilateral pedicle stress fracture occurs as a complication of posterolateral lumbar fusion. Pedicle weakening by prior inserted screws and persistent anterior motion after posterolateral fusion are the contributing factors.