Spinal cord herniation after multilevel anterior cervical corpectomy and fusion for ossification of the posterior longitudinal ligament of the cervical spine.

The authors report the case of a 52-year-old man who had undergone resection of an ossified posterior longitudinal ligament via the anterior approach. The patient experienced postoperative neurological deterioration that may have been caused by a massive cord herniation associated with a dural defect at the corpectomy site. Spinal cord herniation may develop as a complication of anterior cervical decompression. Surgeons should be alert to this condition when planning to treat cervical ossification of the ossified posterior longitudinal ligament via the anterior approach.

Mini-transforaminal lumbar interbody fusion versus anterior lumbar interbody fusion augmented by percutaneous pedicle screw fixation: a comparison of surgical outcomes in adult low-grade isthmic spondylolisthesis.

STUDY DESIGN: Retrospective clinical data analysis. OBJECTIVE: To compare clinical results with radiologic results of 2 fusion techniques for adult low-grade isthmic spondylolisthesis. SUMMARY OF BACKGROUND DATA: There is clear evidence that lumbar interbody fusion using anterior and posterior approaches provides a high fusion rate, good sagittal alignment, and good clinical outcomes. However, there are no recent studies that compare these 2 fusion techniques. METHODS: Between March 2004 and December 2004, 48 patients underwent instrumented mini-anterior lumbar interbody fusion (ALIF) and 46 underwent instrumented mini-transforaminal lumbar interbody fusion (TLIF). The mean follow-up periods were 32.6 and 29.7 months, respectively. RESULTS: The mean visual analog scale (VAS) scores for back and leg pain decreased, respectively, from 7.7 and 7.5 to 2.9 and 2.7 in the ALIF group and from 7.0 and 6.3 to 2.3 and 2.2 in the TLIF group. The mean Oswestry disability index (ODI) scores improved from 51.4% to 23.2% in the ALIF group and from 52% to 14.4% in the TLIF group. In both groups, the VAS and ODI scores significantly changed preoperatively to postoperatively (P<0.001). However, statistical analysis showed no significant difference in postoperative VAS/ODI scores between groups. Radiologic evidence of fusion was noted in 95.8% and 92.3% of the patients in the ALIF group and the TLIF group, respectively. In both the groups, changes in the disc height, segmental lordosis, degree of listhesis, and whole lumbar lordosis (WL) between the preoperative and postoperative periods were significant except for WL in the TLIF group. The amount of change between preoperative and postoperative disc height, segmental lordosis, and WL demonstrated significant intergroup differences (P<0.05). CONCLUSIONS: The mini-ALIF group demonstrated key radiographic advantages compared with the mini-TLIF group for adult low-grade isthmic spondylolisthesis. However, clinical and functional outcomes did not demonstrate significant differences between groups.

Instrumented Minimally Invasive Spinal-Transforaminal Lumbar Interbody Fusion (MIS-TLIF): Minimum 5-Year Follow-Up With Clinical and Radiologic Outcomes.

STUDY DESIGN: A retrospective study. OBJECTIVE: To determine the clinical and radiologic outcomes of the long-term results of instrumented minimally invasive spinal-transforaminal lumbar interbody fusion (MIS-TLIF) in unstable, single-level, low-grade, isthmic spondylolisthesis (IS) or degenerative spondylosis (DS) including degenerative spondylolisthesis, foraminal stenosis with central stenosis, degenerative disk disease, and recurrent disk herniation. SUMMARY OF BACKGROUND DATA: MIS-TLIF is a common surgical procedure to treat lumbar spondylolisthesis. However, there are no studies that have documented the long-term results of MIS-TLIF. METHODS: Forty-four patients who had undergone instrumented MIS-TLIF between July 2003 and January 2005 were retrospectively reviewed. The visual analog scale, Oswestry Disability Index, patient satisfaction rate, and the patient's return-to-work status were used to assess clinical and functional outcomes. Radiologic follow-up were carried out in patients to check for adjacent segmental degeneration (ASD). The plain radiographs, computed tomography and magnetic resonance imaging, were used in all patients in last follow-up period. RESULTS: The mean visual analog scale scores for back and leg pain decreased from 5.8 and 7 to 3.5 and 3.7, respectively, in the DS group (n=19) and from 6.8 and 6.9 to 1.8 and 2.0, respectively, in the IS group (n=25) (P<0.001). The mean Oswestry Disability Index scores improved from 61.7% to 21.5% in the DS group and from 53.9% to 16% in the IS group (P<0.001). Patient satisfaction rate was 80% and 81% in the DS and IS groups, respectively. Evidence of fusion was observed radiologically in 24 (96%) and 19 (100%) of the patients in the IS and the DS group, respectively, giving an overall fusion rate of 97.7% (43/44). The final ASD rate, observed using radiography, was 68.4% (13/19) in the DS and 40% (10/25) in the IS group. However, 15.8% (3/19) in the DS and 4% (1/25) in the IS group had symptoms associated with ASD. CONCLUSIONS: The long-term clinical and radiologic outcomes after instrumented MIS-TLIF in patients with unstable single-level spine are favorable.

Enhancing proliferation and optimizing the culture condition for human bone marrow stromal cells using hypoxia and fibroblast growth factor-2.

This study aimed to determine the cellular characteristics and behaviors of human bone marrow stromal cells (hBMSCs) expanded in media in a hypoxic or normoxic condition and with or without fibroblast growth factor-2 (FGF-2) treatment. hBMSCs isolated from the vertebral body and expanded in these four groups were evaluated for cellular proliferation/migration, colony-forming units, cell-surface characterization, in vitro differentiation, in vivo transplantation, and gene expression. Culturing hBMSCs using a particular environmental factor (hypoxia) and with the addition of FGF-2 increased the cellular proliferation rate while enhancing the regenerative potential, modulated the multipotency-related processes (enhanced chondrogenesis-related processes/osteogenesis, but reduced adipogenesis), and increased cellular migration and collagen formation. The gene expression levels in the experimental samples showed activation of the hypoxia-inducible factor-1 pathway and glycolysis in the hypoxic condition, with this not being affected by the addition of FGF-2. The concurrent application of hypoxia and FGF-2 could provide a favorable condition for culturing hBMSCs to be used in clinical applications associated with bone tissue engineering, due to the enhancement of cellular proliferation and regenerative potential.

Anterior minimally invasive approaches for the cervical spine.

The percutaneous endoscopic discectomy (PECD) with working channel endoscope (WSH) endoscopy set could be a safe and effective minimally invasive surgical option for non-contained cervical disc herniation in selected patients. Judicious use of the end-firing Ho: Yttrium-Aluminium-Garnet (YAG) laser for both decompressive and thermoannuloplasty effect during the percutaneous endoscopic cervical annuloplasty (PECA) is mandatory in order to prevent possible injury to spinal cord or root. Although the percutaneous cervical stabilization (PCS) using the cervical B-Twin may not completely replace the cervical arthrodesis, this minimally invasive procedure can preserve anterior structures and thereby retain segmental stability and prevent the possible kyphotic progression after fusion surgery. To our knowledge, these minimally invasive procedures for cervical spine disease may serve to minimize surgery-induced complications associated with anterior cervical discectomy and fusion (ACDF).

Autogenous Mesenchymal Stem Cells from the Vertebral Body Enhance Intervertebral Disc Regeneration via Paracrine Interaction: An in Vitro Pilot Study.

Several in vivo studies have found that transplanting mesenchymal stem cells (MSCs) into degenerative intervertebral discs (IVDs) leads to regeneration of disc cells. Since the exact underlying mechanisms are not understood, we investigated the mechanisms of action of MSCs in regeneration of degenerative IVDs via paracrine actions. Human MSCs and degenerative disc cells from the same donor vertebrae were directly or indirectly cocultured. The multidifferentiation potential, cell proliferation, collagen synthesis, and mRNA expression levels were assessed. The proliferation rates of MSCs and degenerative disc cells were higher in the coculture system than in the monolayer cultures or in the conditioned medium of each cell type. During coculturing with nucleus pulposus (NP) cells, mRNA expression of the extracellular matrix (ECM) components aggrecan, versican (VCAN), SOX9, and type II and type VI collagen was significantly increased in MSCs, whereas mRNA expression for type V collagen was increased in MSCs cocultured with annulus fibrosus (AF) cells. In addition, the accumulation of total ECM collagen was greater in cocultured degenerative disc cells than in monocultured cells. During coculturing, MSCs downregulated the expression levels of various proinflammatory cytokine genes in degenerative NP [interleukin-1α ( IL-1α), IL-1ß, IL-6, and tumor necrosis factor-α ( TNF-α)] and AF cells ( IL-1α and IL-6), which are involved in the degradation of ECM molecules. In association with the trophic effect of MSCs on degenerative disc cells, upregulation of growth factor mRNA expression was shown in MSCs cocultured with degenerative NP cells [epidermal growth factor ( EGF), insulin-like growth factor-1 ( IGF-1), osteogenic protein-1 ( OP-1), growth and differentiation factor-7 ( GDF-7), and transforming growth factor-ß ( TGF-ß)] or degenerative AF cells ( IGF-1, OP-1, and GDF-7). In terms of MSC-based clinical approaches to IVD regeneration, implanting MSCs into a degenerative IVD may both stimulate MSC differentiation into an NP- or AF-like phenotype and stimulate the biological activation of degenerative disc cells for self-repair.

Novel Technique for Isolating Human Bone Marrow Stem Cells Using Hyaluronic Acid Hydrogel.

Centrifugation based on density gradients is a general methodology for isolating human bone marrow (hBM)-derived mesenchymal stem cells (hBMSCs). The mononuclear cell (MNC) layer can be obtained using a density gradient solution in the conventional protocol, but it is not suitable for direct transplantation due to the possible toxicity of this solution. The results obtained are also influenced by the skill level when applying the technique, which involves time-consuming processes. We have developed a novel protocol for isolating hBMSCs using hyaluronic acid (HA), which is the most widely used injectable biomaterial in clinical settings and a major component of the extracellular matrix. Laying hBM over the HA and then applying centrifugation yielded three separate layers, with the HA layer, including MNCs being the most superficial one. Increasing the volume of HA and/or its crosslinking rate enhanced the yield of MNCs from hBM, and the cell yield was also significantly higher for a lower centrifugal acceleration (530 g) than for a higher one (1500 g). Isolated hBMSCs by HA exhibited similar biological characteristics such as in terms of their proliferation rate, fibroblast-like morphology, cell-cycle status, immunophenotype, and multipotency. The use of either type of hBMSC confirmed the regenerative potential of bone and bone marrow-like tissue in ectopic transplantation models. This is the first report of a novel protocol for isolating hBMSCs that utilize HA. We suggest that this novel isolation technique can be used for the direct application of autogenous MSCs with advantages of being less time-consuming and involving steps that are easier to perform.

Effect of FGF-2 on collagen tissue regeneration by human vertebral bone marrow stem cells.

The effects of fibroblast growth factor-2 (FGF-2) on collagen tissue regeneration by human bone marrow stem cells (hBMSCs) were investigated. hBMSCs were isolated from human vertebral body bone marrow during vertebral surgery and a population of hBMSCs with the characteristics of mesenchymal stem cells was observed. The FGF-2 treatment (5 ng/mL) affected on the colony-forming efficiency, proliferation, and in vitro differentiation of hBMSCs. Insoluble/soluble collagen and hydroxyproline synthesis was significantly enhanced in hBMSCs expanded with FGF-2 and the treatment of FGF-2 caused a reduction in the mRNA expression of collagen type I, but an increase of collagen types II and III along with lysyl oxidase family genes. Collagen formation was also examined using an in vivo assay model by transplanting hBMSCs into immunocompromised mice (n=4) and the histologic and immunohistochemical results revealed that significantly more collagen with a well-organized structure was formed by FGF-2-treated hBMSCs at 8 weeks posttransplantation (P<0.05). The DNA microarray assay demonstrated that genes related to extracellular matrix formation were significantly upregulated. To elucidate the underlying mechanism, chemical inhibitors against extracellular-signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K) were treated and following downstream expression was observed. Collectively, FGF-2 facilitated the collagen-producing potency of hBMSCs both in vitro and in vivo, rendering them more suitable for use in collagen regeneration in the clinical field.

Human bone marrow stem cells cultured under hypoxic conditions present altered characteristics and enhanced in vivo tissue regeneration.

Human bone marrow mesenchymal stem cells (hBMSCs) were isolated from bone marrow of the vertebral body. The hBMSCs were cultured under either hypoxic (1% O2) or normoxic (21% O2; control) conditions and the characteristics as mesenchymal stem cells were compared. Results revealed that hypoxia reduced proliferative potential and colony-forming efficiency of hBMSCs, and significantly enhanced osteogenic and chondrogenic differentiation. The hBMSCs enhanced the regenerative potential of bone in vivo. In vitro synthesis of soluble and insoluble collagen was significantly increased in the hypoxic condition. In vivo collagen tissue regeneration was also enhanced under the hypoxic condition, with concomitant increased expressions of various subtypes of collagen and lysyl-oxidase family mRNA. MicroRNA assays revealed that miR-155-5p, which negatively regulates HIF-1α, was significantly highly expressed. These observations demonstrate that hBMSCs obtained from human vertebrae exhibit altered characteristics under hypoxic conditions, and each factor contributing to hBMSC-mediated tissue healing should be evaluated with the goal of allowing their clinical application.

Differential effect of water-soluble chitin on collagen synthesis of human bone marrow stem cells and human periodontal ligament stem cells.

Human bone marrow stem cells (hBMSCs) represent a promising regenerative material because of their mutipotency, including their ability to regenerate collagenous soft tissues. We previously found that water-soluble chitin (WSC) enhances the ability of human periodontal ligament stem cells (hPDLSCs) to synthesize collagen tissue. The aim of this study was to determine the effects of WSC on hBMSCs and hPDLSCs for the collagen synthesis both in vitro and in vivo. hBMSCs and hPDLSCs were isolated and expanded with or without 0.3 mg/mL WSC. A series of in vitro and in vivo analyses were performed to evaluate their characteristics as stem cell populations. Then, collagen and hydroxyproline assays were conducted using both in vitro and in vivo assay models, and the real-time polymerase chain reaction was performed to analyze the expression of collagen-related markers. WSC-treated and nontreated hBMSCs and hPDLSCs were transplanted into immunocompromised mice, and histology and immunohistochemistry analyses were conducted after 8 weeks. The in vitro results showed that those cells possessed the characteristics of mesenchymal stem cells. The amount of soluble collagen synthesized was significantly greater in WSC-treated hBMSCs than in the nontreated group; conversely, treatment of hPDLSCs with WSC decreased the formation of soluble collagen. The amount of insoluble collagen synthesized was greater in the WSC-treated groups than in the nontreated groups for both hBMSCs and hPDLSCs. The hydroxyproline contents of the regenerated soluble and insoluble collagens were similar. The expressions of mRNA for collagen types I-V, hyaluronic acid synthase 1 (HAS1), HAS2, and HAS3, and the LOX family were higher in WSC-treated hPDLSCs than in the nontreated group, whereas WSC increased the expression of collagen type III and decreased that of collagen type I in hBMSCs. The histology and immunohistochemistry results revealed that WSC significantly increased the amount of collagen formed in vivo by both types of stem cells. Collectively, treatment with WSC significantly enhanced the collagen-forming potentials of hBMSCs and hPDLSCs, but the collagen they produced exhibited distinctively different characteristics. These findings suggest that the appropriate stem-cell source should be chosen based on the purpose of the required regenerated tissue.

Adjacent segment degeneration after lumbar interbody fusion with percutaneous pedicle screw fixation for adult low-grade isthmic spondylolisthesis: minimum 3 years of follow-up.

BACKGROUND: Although favorable clinical outcomes have been reported for instrumented lumbar interbody fusion (LIF), adjacent segment degeneration (ASD) has been reported as a long-term complication after LIF. OBJECTIVE: To investigate ASD after instrumented LIF performed at a single level and only for the homogeneous disease of adult low-grade isthmic spondylolisthesis. METHODS: A total of 128 patients who had undergone LIF for the treatment of adult low-grade isthmic spondylolisthesis involving the lower lumbar spine at our institution between February 2001 and December 2004 were retrospectively reviewed by chart review and telephone survey. Of them, 103 patients with a minimum of a 36-month follow-up period were enrolled in this study. The mean age was 48.5 years. The average follow-up period was 59 months. Clinical and radiological data related to segmental lordosis (SL), whole lumbar lordosis, sacral slope, pelvic tilt, pelvic incidence, and L1 axis S1 distance were analyzed to identify significant risk factors for ASD. RESULTS: The overall incidence of ASD was 10.6% (11/103). The incidences of radiographic and symptomatic ASD were 8.7% (9/103) and 1.9% (2/103), respectively. All patients improved clinically and functionally during the follow-up period. Postoperative SL, preoperative SL, whole lumbar lordosis, and L1 axis S1 distance were significant risk factors for ASD. Only SL was a significant risk factor for both the preoperative and postoperative states. CONCLUSION: ASD may occur at a relatively lower incidence in adult low-grade isthmic spondylolisthesis compared with other degenerative lumbar spinal diseases. SL is significantly correlated with ASD, whereas mechanical alterations caused by LIF are less likely to affect the adjacent segment. Restoration of normal SL is important for preventing ASD, and long-term follow-up is necessary.

Thrombosis of left common iliac artery following anterior lumbar interbody fusion: case report and review of literatures.

We report on a case of thrombosis of the left common iliac artery following anterior lumbar interbody fusion (ALIF) of L4-5 in a 79-year-old man with no previous medical problems, including peripheral vascular disease. After completing the ALIF procedure, the surgeon could not feel the pulsation of the left dorsalis pedis artery, and the oxygen saturation (SaO(2)) had fallen below 90% from pulse oxymetry on the left great toe. Thrombectomy was successfully performed after confirming the thrombus in the left common iliac artery using Computed Tomography (CT) angiography. Thrombosis of the common iliac artery is very rare following ALIF. However, delayed diagnosis can lead to disastrous outcome. Although elderly patients have no cardio-vascular disease or vessel calcification in pre-op evaluation, the possibility of a complication involving L4-5 should be considered.

Dynamic lumbar spinal stenosis : the usefulness of axial loaded MRI in preoperative evaluation.

Two cases of dynamic lumbar spinal stenosis were identified by the authors using axial loaded magnetic resonance image (MRI). In both cases, the patients presented with neurogenic claudication but MRI in decumbency showed no definite pathologic condition associated with their symptoms. In contrast, axial loaded MRI demonstrated constrictive spinal stenosis and a significantly decreased dural sac caused by epidural fat buckling and thickening of the ligamentum flavum in both cases. In the second case, a more prominent disc protrusion was also demonstrated compared with decumbent MRI. After decompressive surgery, both patients had satisfactory outcomes. Axial loaded MRI can therefore give decisive information in dynamic spinal disorders by allowing simulation of an upright position.

CT-guided percutaneous vertebroplasty in the treatment of an upper thoracic compression fracture.

Percutaneous vertebroplasty (PVP) has been used to relieve pain and to prevent further collapse of the vertebral body in patients with an osteoporotic compression fracture. The most commonly affected site for the use of PVP is the thoracolumbar junction. There are few reports that have described on the usefulness of PVP in the treatment of a high thoracic compression fracture. We report a case of an upper thoracic compression fracture that was treated with computed tomography (CT)-guided PVP. It was possible to obtain easy access to the narrow thoracic pedicle and it was also possible to monitor continuously the proper volume of polymethylmethacrylate employed, under CT guidance.

Percutaneous endoscopic approach for highly migrated intracanal disc herniations by foraminoplastic technique using rigid working channel endoscope.

STUDY DESIGN: A retrospective analysis of 59 patients operated for excision of soft highly migrated intracanal lumbar disc herniations by percutaneous endoscopic foraminoplasty. OBJECTIVE: To describe a safe and effective percutaneous endoscopic technique for removal of migrated herniations and report the results on the basis of modified MacNab criteria. SUMMARY OF BACKGROUND DATA: Migrated herniations pose a great challenge even for experienced endoscopic surgeons. These herniations are hidden from the endoscopic view by anatomic barriers like hypertrophied facet, inferior pedicle and foraminal ligaments rendering percutaneous endoscopic transforaminal lumbar discectomy (PELD) by conventional approach, difficult with high failure rate. Foraminoplasty, which means enlargement of foramen by undercutting ventral part of superior-facet, upper border of inferior pedicle along with ablation of foraminal ligament, can help us to address this issue. METHODS: Fifty-nine patients with soft highly migrated herniations who underwent PELD with foraminoplasty under local anesthesia from January 2002 to June 2006 were analyzed retrospectively. Patients were evaluated by postoperative Visual Analog Scale for leg pain and Oswestry Disability Index scores. Outcomes were graded according to modified MacNab criteria. RESULTS: Mean follow-up was 25.4 months. Mean visual analog scale score for radicular pain improved from 8.01 to 1.56, and mean Oswestry disability Index improved from 61.6 to 10.76. Based on modified MacNab criteria, 91.4% of patients experienced satisfactory outcome. Three patients had persistent leg pain after surgery. One patient underwent a repeat-PELD on next day and the other after 1 month. Both were relieved of symptoms. Third patient was subjected to open discectomy after 25 weeks from the first operation and showed improvement. Two patients had recurrent herniation at same level after 6 months; 1 patient underwent repeat PELD, and the other underwent open discectomy. Both patients had good results. CONCLUSION: Foraminoplastic-PELD is safe and effective procedure for surgical treatment of soft migrated herniations. The results are comparable to results of open discectomy.

Modified transcorporeal anterior cervical microforaminotomy for cervical radiculopathy: a technical note and early results.

A prospective analysis of the first twenty patients operated for cervical radiculopathy by a new modification of transcorporeal anterior cervical foraminotomy technique. To evaluate early results of a functional disc surgery in which decompression for the cervical radiculopathy is done by drilling a hole in the upper vertebral body and most of the disc tissue is preserved. Earlier approaches to cervical disc surgery either advocated simple discectomy or discectomy with fusion, ultimately leading to loss of motion segment. Posterior foraminotomy does not address the more common anterior lesion. Twenty patients suffering from cervical radiculopathy not responding to conservative treatment were chosen for the new technique. Upper vertebral transcorporeal foraminotomy was performed with the modified technique in all the patients. All the patients experienced immediate/early relief of symptoms. No complications of vertebral artery injury, Horner's syndrome or recurrent laryngeal nerve palsy were noted. Modified transcorporeal anterior cervical microforaminotomy is an effective treatment for cervical radiculopathy. It avoids unnecessary violation of the disc space and much of the bony stabilizers of the cervical spine. Short-term results of this technique are quite encouraging. Longer-term analysis can help in outlining the true benefits of this technique.

CHARITE versus ProDisc: a comparative study of a minimum 3-year follow-up.

STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate and compare clinical and radiologic outcomes of the CHARITE and ProDisc. SUMMARY OF BACKGROUND DATA: There is no clinical report comparing CHARITE and ProDisc. METHODS: Among a total of 61 patients who underwent total disc replacement, 57 patients followed more than 3 years were enrolled. The CHARITE was used in 33 patients and ProDisc in 24. MRI follow-up was possible in 52 patients. Clinical and radiologic data including range of motion (ROM) and facet degeneration of the replaced segment, and degeneration of the disc at the adjacent level were evaluated. RESULTS: Mean percentage improvement of Oswestry Disability Index (ODI) score was 78.9% in the CHARITE group and 75.8% in ProDisc group. The mean improvement of the Visual Analogue Scale (VAS) pain score was 72% in the CHARITE and 74.2% in ProDisc. There was no statistical difference between 2 groups in improvement rates either of the ODI scores and VAS scores. Degradation of the facets was seen in 36.4% of the CHARITE and 32% of the ProDisc. Degradation of disc degeneration at the adjacent level above the index level was seen in 19.4% in the CHARITE and 28.6% in the ProDisc. The degradation rates of facet joints and disc at adjacent segment between the 2 groups were not significantly different. Segmental ROM of the replaced segments was well preserved, but ROM of L5-S1 of the ProDisc was significantly less than that of the CHARITE. CONCLUSIONS: While clinical outcomes of both CHARITE and ProDisc groups were fairly good, the facet joint of the index level and the disc at the adjacent level showed an aggravation of the degenerative process in a significant number of patients, regardless of the device used, raising concerns of possible late consequences of total disc replacement, especially regarding facet arthrosis and adjacent segment disease.

Fluoroscopically assisted percutaneous translaminar facet screw fixation following anterior lumbar interbody fusion: technical report.

STUDY DESIGN: A technical report of fluoroscopically assisted percutaneous translaminar facet screw fixation after anterior lumbar interbody fusion (ALIF). OBJECTIVES: To describe a minimally invasive translaminar facet screw fixation technique that was modified from the Magerl method, and to assess its technical feasibility and clinical efficacy. SUMMARY OF BACKGROUND DATA: There is no previous study in the literature on percutaneous translaminar facet screw fixation assisted only by fluoroscopy without using any specially designed guiding device. Also, there is no previous study involving a screw insertion technique in which the screw is directed to purchase the pedicle while traversing the lamina and transfixing the facet joint. METHODS: A total of 20 patients with degenerative spinal disease underwent ALIF and supplementary percutaneous translaminar facet screw fixation under fluoroscopic guidance from 2001 through 2002. Their clinical and radiologic data were collected and analyzed. RESULTS: A total of 65 screws were inserted. Seven screws (10.8%) were found to have violated laminae walls but none injured or compressed neural structures directly. The purchases of the facet joints were all successful, but insertion into the pedicle in perfect position was successful in 55 screws (84.6%). Radiologic fusion occurred in all fused levels (100%). Estimated blood loss was 222.5 mL (100-520), and no blood transfusions were needed in any of the cases. There was only one complication related to facet screw fixation, in which the distal tip of a superior articular process was fractured caused by repeated drilling with a K-wire. CONCLUSIONS: Percutaneous translaminar facet screw fixation using fluoroscopy is technically feasible. It seems that the fluoroscopically assisted percutaneous translaminar facet pedicle screw fixation is a useful, minimally invasive posterior augmenting method following ALIF.

Factors affecting prognosis of patients who underwent corpectomy and fusion for treatment of cervical ossification of the posterior longitudinal ligament: analysis of 47 patients.

OBJECTIVE: Even though cervical ossification of the posterior longitudinal ligament (OPLL) has several unique clinical features compared with spondylotic myelopathy or cervical disc disease, there have been few reports about factors affecting prognosis after decompression using corpectomy. To clarify the prognostic factors for cervical OPLL, the authors analyzed the clinical and radiologic parameters of 47 patients retrospectively. METHODS: The patients were classified into a good-prognosis group and a poor-prognosis group according to the changes of Nurick grade after operation. Age at operation, gender, preoperative Nurick grade, duration of symptoms, snake-eye appearance, occupying ratio, type of OPLL, Pavlov ratio, and double-layer sign did not affect the prognosis significantly. RESULTS: Multiple logistic regression analysis revealed that diabetes mellitus (DM) was the only statistically significant factor predicting poor prognosis for the patients with cervical OPLL who underwent corpectomy and fusion. CONCLUSIONS: Surgeons do not have to be discouraged from performing anterior decompression for the patients with cervical OPLL on the basis of age, severity of disease (preoperative Nurick grade or occupying ratio), irreversible changes in gray matter of the spinal cord (snake-eye appearance), or duration of symptoms. We should direct our attention to DM as a potent risk factor for cervical OPLL and try to clarify the mechanism by which DM possibly affected the functional recovery of the patients.