Hypertrophy of ligamentum flavum in lumbar spinal stenosis associated with increased proteinase inhibitor concentration

BACKGROUND: It is well known that age-related fibrosis, or decreases in the elastin-to-collagen ratio of the ligamentum flavum, along with hypertrophy of the ligamentum flavum, are associated with lumbar spinal stenosis. However, the molecular mechanism by which this fibrosis and hypertrophy develop is unknown. Tissue inhibitors of matrix metalloproteinase (TIMPs) are proteinase inhibitors that suppress extracellular matrix degradation. Elevated TIMP-1 and TIMP-2 expression has been implicated in various fibrotic diseases of the liver, kidney, lung, and heart. These TIMPs can also induce cellular proliferation and inhibit apoptosis in a wide range of cell types. These findings led us to postulate that TIMP-1 and TIMP-2 might also be associated with hypertrophy and fibrosis of the ligamentum flavum in lumbar spinal stenosis. METHODS: We quantified and localized TIMP expression in ligamentum flavum tissues that had been obtained during surgery from thirty patients with spinal stenosis and from thirty gender-matched control patients with disc herniation. The thickness of the ligamentum flavum at the level of the facet joint was measured on axial T1-weighted magnetic resonance images. In addition, we examined ligamentum flavum tissues for the expression of markers of cellular proliferation and apoptosis. RESULTS: The ligamentum flavum was significantly thicker in the patients with spinal stenosis (mean, 5.68 mm) than in the patients with disc herniation (mean, 2.70 mm) (p < 0.001). The concentration of TIMP-2 in the ligamentum flavum was significantly higher in the patients with spinal stenosis (mean, 12.62 ng/mL) than in those with disc herniation (mean, 8.85 ng/mL) (p = 0.028). TIMP-1 and TIMP-2 were detected in the cytoplasm of ligamentum flavum fibroblasts. TIMP-1 and TIMP-2 concentrations were associated with hypertrophy of the ligamentum flavum (p = 0.015 and p = 0.003, respectively). None of the samples from the patients with stenosis had evidence of proliferation of ligamentum flavum fibroblasts. The expression of markers for apoptosis was significantly higher in the patients with spinal stenosis (58.8%) than in those with disc herniation (26.6%) (p < 0.001). CONCLUSIONS: Increased TIMP expression has been implicated in fibrosis and hypertrophy of the extracellular matrix of several organs. Our results suggest that increased expression of TIMP-2 in ligamentum flavum fibroblasts is associated with fibrosis and hypertrophy of the ligamentum flavum in patients with spinal stenosis.     

Biomechanical analysis of cervical spondylotic myelopathy: the influence of dynamic factors and morphometry of the spinal cord

Objective

Patients with cervical spondylotic myelopathy (CSM) have the same clinical symptoms that vary according to the degree of spinal cord compression and the cross-sectional cord shape. We used a three-dimensional finite element method (3D-FEM) to analyze the stress distributions of the spinal cord with neck extension under three cross-sectional cord shapes.

Methods

Experimental condition for the 3D-FEM spinal cord, ligamentum flavum, and anterior compression shape (central, lateral, and diffuse types) was established. To simulate neck extension, the spinal cord was extended by 20° and the ligamentum flavum was shifted distally according to movement of the cephalad lamina.

Results

The stress distribution in the spinal cord increased due to invagination of the ligamentum flavum into the neck extension. The range of stress distribution observed for the diffuse type was wider than for the central and lateral types. In addition, the stress distribution in the spinal cord was increased by the pincer movement of the ligamentum flavum and by the anterior compression of the spinal cord. The range of stress distribution observed for the diffuse type under antero-posterior compression was also wider than for the central and lateral types.

Conclusion

This simulation model showed that the clinical symptoms of CSM due to compression of the diffuse type may be stronger than for the central and lateral types. Therefore, careful follow-up is recommended for anterior compression of the spinal cord of diffuse type.     

Quantitative analysis of transforming growth factor-beta 1 in ligamentum flavum of lumbar spinal stenosis and disc herniation.

STUDY DESIGN: The concentration of transforming growth factor-beta 1 (TGF-beta1) was examined in the ligamentum flavum of lumbar spinal stenosis and disc herniation. OBJECTIVE: To investigate the role of TGF-beta1 on hypertrophy of the ligamentum flavum in lumbar spinal stenosis compared with that of lumbar disc herniation. SUMMARY OF BACKGROUND DATA: The hypertrophy of the ligamentum flavum is known to be related to degenerative changes that are secondary to the aging process or mechanical instability. However, there has been no study to investigate the effect of biochemical factors, such as growth factors, associated with hypertrophy of the ligamentum flavum. METHODS: The concentrations of TGF-beta1 were analyzed in the surgically obtained ligamentum flavum specimens from lumbar spinal stenosis (n = 10; mean age 62.8 years) and disc herniation (n = 10; mean age 35.6 years) by enzyme-linked immunosorbent assay. The localization of TGF-beta1 within the ligamentum flavum was determined using immunohistochemical study. The thickness of the ligamentum flavum was measured with axial T1-weighted magnetic resonance imaging. The biochemical and radiologic results were compared for these two conditions. RESULTS: The mean concentration of TGF-beta1 was 123.78 pg/100 microg protein (range 11-374 pg/100 microg protein) in lumbar spinal stenosis and 38.56 pg/100 microg protein (range 0-155 pg/100 microg protein) in lumbar disc herniation; the difference between lumbar spinal stenosis and disc herniation was statistically significant (P = 0.029). The mean thickness of the ligamentum flavum was 4.44 mm (range 3.4-5.4 mm) in lumbar spinal stenosis and 2.44 mm (range 1.8-4.0 mm) in lumbar disc herniation; the difference between lumbar spinal stenosis and disc herniation was statistically significant (P = 0.001). On immunohistochemical study TGF-beta1 was positively stained on the fibroblasts within the ligamentum flavum specimens. CONCLUSION: The current results suggest that higher expression of TGF-beta1 by fibroblasts might be related to the development of hypertrophy of the ligamentum flavum in lumbar spinal stenosis.     

Immunohistochemical analysis of TIMP-2 and collagen types I and IV in experimental spinal cord ischemia-reperfusion injury in rats

Background

Thoracic and thoracoabdominal aortic intervention carries a significant risk of spinal cord ischemia. The pathophysiologic mechanisms that cause hypoxic/ischemic injury to the spinal cord have not been totally explained. In normal spinal cord, neurons and glial cells do not express type IV collagen. Type IV collagen produced by reactive astrocytes is reported to participate in glial scar formation. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors that regulate the activity of the matrix metalloproteinases (MMPs). TIMP-2 binds strongly with MMP-2, facilitating activation by membrane-type MMP. Imbalance between TIMPs and MMPs can lead to excessive degradation of matrix components. Type IV collagen involved in the blood–brain barrier disruption and glial scar formation, TIMP-2 influences MMP-2 that controls degradation of collagen I and IV.

Objective

To examine the immunohistochemical analysis of TIMP-2 and collagen types I–IV in experimental spinal cord ischemia–reperfusion in rats.

Methods

Thirty-two male Wistar rats weighing 250–300 g were divided into four groups: group S: sham group (n = 8); group 0P: 30-minute occlusion without perfusion (n = 8); group 3P: 30-minute occlusion and 3-hour perfusion (n = 8); and group 24P: 30-minute occlusion and 24-hour perfusion (n = 8). Infrarenal aorta was cross-clamped at two sites by using two aneurysm clips for 30 minutes. Reperfusion was provided after removal of the clips. Lumbar spinal cord segments were removed for immunohistochemical analysis.

Results

TIMP-2 and collagen staining in 3-hour perfused (3P) group were nearly the same with sham group (S). TIMP-2 and collagen staining increased in the 24-hour perfused group.

Conclusion

Alterations in collagen levels may relate to the biphasic breakdown of the blood–brain barrier and collagen staining in new cell types with relation to glial scar formation. Our results demonstrate that 3-hour perfusion after occlusion in hypoxic/ischemic spinal cord injury seems to be the critical reversible period.     

Herniated nucleus pulposus in isthmic spondylolisthesis: higher incidence of foraminal and extraforaminal types

Background  

The purpose of this study was to evaluate the pattern of disc herniation and to investigate the associated symptoms in cases of isthmic spondylolisthesis. It is well known that the pathogenesis of degenerative spondylolisthesis associates with disc degeneration, followed by facet laxity and ligamentum flavum hypertrophy, which result in severe spinal canal stenosis. But isthmic spondylolisthesis is known to have a different pathogenesis. In isthmic spondylolisthesis, pseudodisc bulging is easily identified, and canal stenosis is comparatively rare. Therefore, we propose that isthmic spondylolisthesis has a different pattern of disc herniation from degenerative spondylolisthesis. We studied the type, incidence of disc herniation and clinical symptoms related to isthmic spondylolisthesis.     

Comparison of wire and disc leads to activate the expiratory muscles in dogs

Objective

Respiratory complications account for a major cause of morbidity and mortality in subjects with spinal cord injury (SCI) due to paralysis of the expiratory muscles and the consequent inability to generate effective cough. We demonstrated previously that effective cough can be restored in SCI via spinal cord stimulation (SCS) with disc leads positioned on the lower thoracic and upper lumbar spinal cord via laminotomy incisions. In this study, the effectiveness of wire leads, which can be placed using minimally invasive techniques, to activate the expiratory muscles was evaluated.

Design

Animal study.

Setting

Research laboratory.

Animals

Dogs (n = 8).

Interventions

In separate trials, disc and wire leads were inserted onto the dorsal epidural space at the T9, T11, and L1 spinal cord levels. Effects of electrical stimulation with disc, single wire, and two wire leads placed in parallel were compared.

Outcome measures

Airway pressure generation following stimulation with disc and various configurations of wire leads were compared.

Results

Several different configurations of wire leads resulted in airway pressures that were similar to those generated with monopolar stimulation with disc leads (MSDLs). For example, combined monopolar stimulation with parallel wire leads at the T9 + T11 and T9 + L1 levels resulted in airway pressures that were 103.5 ± 6.4 and 101.9 ± 7.0%, respectively, of those achieved with MSDL. Bipolar stimulation with parallel wire leads at T9–T11 and T9–L1 resulted in airway pressures that were 94.2 ± 3.4 and 96.8 ± 5.0%, respectively, of the pressures achieved with MSDL. Other wire configurations were also evaluated, but were generally less effective.

Conclusion

These results suggest that specific configurations of wire leads, which can be placed via minimally invasive techniques, result in comparable activation of the expiratory muscles compared to disc leads and may be a useful technique to restore cough in persons with SCI.     

Progressive thoracic myelopathy caused by spinal calcium pyrophosphate crystal deposition because of proximal junctional vertebral compression fracture after lumbopelvic fusion

Purpose

We describe cases presenting with progressive thoracic myelopathy after lumbopelvic fusion attributed to proximal junctional vertebral compression fracture (PJF) followed by spinal calcium pyrophosphate dehydrate (CPPD) crystal deposition.

Methods

The study included six patients, ranging from 62 to 75 years. All patients had been treated previously with lumbopelvic fusion. The mean period from the detection of PJF to the onset of myelopathy was 4.8 months. Notably, five patients demonstrated upper-instrumented vertebra (UIV) collapse.

Results

After revision surgery involving decompressive laminectomy and extension of the spinal fusion, all patients experienced significant improvement. Photomicrographs of the resected ligamentum flavum showed CPPD crystals and multinucleated giant cells.

Conclusions

The combination of mechanical stress plus PJF and CPPD crystal deposition followed by a foreign body reaction to the deposited crystals caused myelopathy. Patients with radiographic evidence of PJF, especially UIV collapse, after lumbopelvic fusion should be followed carefully for the emergence of myelopathy.     

The safety and efficacy of minimally invasive discectomy: a meta-analysis of prospective randomised controlled trials

Purpose

The objective of this study was to compare the safety and efficacy of minimally invasive discectomy (MID) with standard discectomy (SD) and determine whether the use of the MID technique could decrease the recurrence of lumbar disc herniation (LDH) after the surgery.

Methods

In February 2014, a comprehensive search was performed in PubMed, EMBASE, Web of Science, Cochrane Library and the Chinese Biological Medicine Database. Only randomised controlled trials (RCT) that compared MID with SD for the surgical management of LDH were included. These trials were carefully picked out following the inclusion and exclusion criteria. Using the Cochrane Collaboration guidelines, two authors independently extracted data and assessed these trials’ quality. The age of the patients, size of incision, surgical time, blood loss, visual analogue scale (VAS) score after the surgery, hospital stay, disc herniation recurrence, X-ray exposure and surgical costs in these studies were abstracted and synthesised by a meta-analysis with RevMan 5.2.0 software, and the main results (VAS score after the surgery and disc herniation recurrence) of publication bias were examined by Stata 12.0.

Results

Overall, 16 trials involving 2,139 patients meeting our criteria were included and analysed. Comparing MID and SD, the former was more likely to increase disc herniation recurrence [relative risk (RR) = 1.95, 95 % confidence interval (CI) 1.19–3.19, p = 0.008], and it involved a smaller size of incision [mean difference (MD) = −1.91, 95 % CI −3.33 to −0.50, p = 0.008], shorter hospital stay, longer operating time (MD = 11.03, 95 %C I 6.62–15.44, p < 0.00001) and less blood loss (MD = −13.56, 95 % CI −22.26 to −4.87, p = 0.002), while no statistical difference appeared with regard to the age of the patients, VAS score after the surgery, X-ray exposure, hospital stay and surgical costs.

Conclusions

Based on available evidence, MID results in less suffering for patients during the hospital course with a similar clinical efficacy compared to SD. This makes MID a promising procedure for patients with LDH; however, to popularise it greater effort is required to reduce disc herniation recurrence.     

Experimental Disc Herniation in the Rat Causes Downregulation of Serotonin Receptor 2c in a TNF-dependent Manner

Background

During recent decades, the knowledge of the pathophysiology of disc herniation and sciatica has drastically improved. What previously was considered a strict biomechanical process is now considered a more complex interaction between leaked nucleus pulposus and the tissue in the spinal canal. An inflammatory reaction, with tumor necrosis factor (TNF) playing an essential role, has been demonstrated. However, the exact mechanisms of the pathophysiology of disc herniation remain unknown.

Questions/purposes

In this study we use an animal model to investigate (1) if and/or how experimental disc herniation affects gene expression in the early phase (24 hours postsurgery) in the dorsal root ganglion; and (2) if TNF inhibition can reduce any observed changes.

Methods

A rat model of disc herniation was used. Twenty rats were evenly divided into four groups: naïve, sham, disc herniation, and disc herniation with TNF inhibition. The dorsal root ganglion of the affected nerve root was harvested 24 hours after surgery and analyzed with a TaqMan Low Density Array^® quantitative polymerase chain reaction assay. Gene expression levels in sham were compared with disc herniation to assess question 1 and disc herniation to disc herniation with TNF inhibition to assess question 2.

Results

Experimental disc herniation caused a decrease in the expression of the serotonin receptor 2c gene (p = 0.022). TNF inhibition was found to reduce the observed decrease in expression of serotonin receptor 2c (p = 0.037).

Conclusions

Our results suggest that a decrease in the expression of the serotonin receptor 2c gene may contribute to the pathophysiology of disc herniation. Further research on its involvement is warranted.

Clinical Relevance

This pilot study gives a brief insight into cellular changes that may contribute to the pathophysiology of disc herniation. This knowledge may contribute to the development of more and better treatment options for patients with disc herniation and sciatica.     

The modulation of spinal growth with nitinol intervertebral stapling in an established swine model

Purpose

Anterior spinal stapling for the treatment of adolescent idiopathic scoliosis has been shown to slow progression in small curves; however, its role in larger curves remains unclear. The purpose of this study was to evaluate the effectiveness of nitinol staples to modulate spinal growth by evaluating the two-dimensional and three-dimensional morphological and histological effects of this method in a well-established porcine model.

Methods

Three immature Yucatan miniature pigs underwent intervertebral stapling. Two staples spanned each of three consecutive mid-thoracic discs and epiphyses. Monthly radiographs were obtained. Computed tomography (CT) was conducted at harvest after 6 months of growth. Measurements of wedging and height for each disc and vertebral body were conducted. Micro CT was used to compare physeal closure between stapled and non-stapled levels. Histology of the growth plate also compared the hypertrophic zone thickness for control and stapled vertebrae.

Results

After 6 months of stapled growth, the average coronal Cobb angle of the stapled segments increased by 7.7 ± 2.0° and kyphosis increased by 3.3 ± 0.6° compared to preoperative curves. Increased vertebral wedging and decreased disc height (p < 0.001) were noted in stapled regions. Overall, 26 ± 23 % of each growth plate was closed in the stapled segments, with 6 ± 8 % closure in the unstapled levels. No difference was observed regarding the hypertrophic zone height when comparing instrumented to uninstrumented levels, nor was a difference recognized when comparing right versus left regions within stapled levels alone.

Conclusions

Six months of nitinol intervertebral stapling created a mild coronal and sagittal deformity associated with reduced vertebral and disc height, and increased coronal vertebral and sagittal disc wedging.     

Driving reaction time before and after surgery for lumbar disc herniation in patients with radiculopathy

Purpose

Although patients scheduled to undergo lumbar disc surgery often ask when they are allowed to drive a motor vehicle again, there are no published recommendations on this subject.

Methods

We conducted a prospective study in 46 consecutive patients (mean age 48.9 years) to determine driving reaction time (DRT) before and after surgery in patients with lumbar disc herniation. Of the patients 23 had left-side radiculopathy and 23 right-side radiculopathy. Driving reaction time as well as back and leg pain were evaluated preoperatively, on the day of discharge from hospital and at the 5-week follow-up examination (FU). 31 healthy subjects were tested as controls.

Results

Significant improvement in DRT was seen for both patient samples (p < 0.05). For patients with a right-side radiculopathy preoperative DRT was 664 ms (median, IQR: 241), which was reduced to 605 ms (median, IQR: 189) immediately postoperatively and to 593 ms (median, IQR: 115) at FU. For patients with a left-side radiculopathy DRT was 675 ms (median, IQR: 247) preoperatively, 638 ms (median, IQR: 242) postoperatively and 619 ms (median, IQR: 162) at FU. Pain was moderately correlated to DRT. Control subjects had a driving reaction time of 487 (median, IQR: 116), which differed significantly from patients at all three testing times (p < 0.001).

Conclusion

Our data indicate a positive effect of the surgery on driving ability. Therefore, we would suggest that for both patient samples it is safe to continue driving after hospital discharge. However, patients have to be informed about increased DRT caused by radiculopathy already before surgery.     

Reoperation after lumbar disc surgery in two hundred and seven patients

Purpose

The purpose of this study was to compare the causes and characteristics of reoperations after different primary operations for lumbar disc herniation (LDH).

Methods

Out of a series of 5,280 patients who underwent operations for LDH between 2001 and 2012, 207 patients (135 male and 72 female, mean age 47.7 years) underwent primary and revision operations, which were included in this study. The following clinical parameters were retrospectively assessed: the primary surgical methods, the intervals between primary and revision operations, and surgical findings in the revisions.

Results

In total, 232 lumbar discs underwent reoperations. One hundred and nineteen reoperations were performed after microendoscopic discectomy (MED group), 68 after percutaneous endoscopic lumbar discectomy (PELD group) and 45 after open disc surgery (open group). The locations of revision operations had priority over those of primary surgery, with a moderate correlation (kappa coefficient = 0.533). A total of 46.6 % of reoperations were performed within 0.5 years after primary surgery, and 35.3 % were performed between one and five years. Real recurrent herniation (homolateral herniations at the same level) was significantly more common than other reoperative surgical findings (70.6 % in PELD group, 47.1 % in MED group, 37.8 % in open group). The overall mean interval until revision surgery was 18.9 months (8.1 months in the PELD group vs. 19.7 months in the MED group vs. 33.1 months in the open group, p < 0.01).

Conclusions

For LDH, real recurrent herniation was the most common cause of reoperations, and more reoperations for real recurrent herniations and shorter intervals were found after minimally invasive endoscopic discectomy than after open disc surgery.     

Morphological changes in disc herniation in the lower cervical spine: an ultrastructural study

Introduction

The basis of disc degeneration is still unknown, but is believed to be a cell-mediated process. Apoptosis might play a major role in degenerative disc disease (DDD). The aim of this study was to correlate the viability of disc cells with the radiological degeneration grades (rDG) in disc herniation.

Materials and methods

Forty anterior IVD’s (C4–C7) from 39 patients with DDD were studied histologically and ultrastructurally to quantify healthy, “balloon”, chondroptotic, apoptotic and necrotic cells. Patients were classified to their rDG, as having either prolapse (P: DGII + III) and/or osteochondrosis (O: DGIV + V). Similar studies were undertaken on eight control discs.

Results

Cell death by necrosis (mean 35%) was common but differed not significantly in both groups. All patients with a disc prolapse DGII + III revealed balloon cells (iAF: mean 32%). All appeared alive and sometimes were hypertrophic. However, significantly less balloon cells were found in the O-Group. Control samples revealed no evidence of “balloon” cells in DGII and only a minor rate in DGIII.

Conclusion

According to the different rDG, quantitative changes were obvious in healthy and “balloon” cells, but not for cell death. At the moment it can only be hypothesized if “balloon” cells are part of a repair strategy and/or cause of disc herniation.     

Full-endoscopic cervical arcocristectomy for the treatment of spinal stenosis: results of a cadaver study

Purpose

Cervical spondylotic myelopathy is a multifactorial disease that is directly correlated by the degree of spinal stenosis. Surgery remains the best therapy. A posterior approach is often recommended in patients with multilevel dorsal cervical compression. Aim of the present experimental study was to evaluate the feasibility of a full-endoscopic arcocristectomy in a cadaver study.

Methods

We performed full-endoscopic arcocristectomy on ten formalin-fixed human cervical specimens. Before and after decompression we obtained high-resolution computerized tomography (CT) data to evaluate the diameter of the cervical spinal canal.

Results

Overall, surgery was possible on 55 segments in ten cadaver specimens. A mean increase of 4.1 mm (±1.2 mm) in the sagittal diameter of the cervical spinal canal could be achieved (p < 0.05, t test).

Conclusions

The full-endoscopic arcrocristectomy is feasible and achieves a sufficient decompression. This minimal invasive technique protects most of the dorsal structures and therefore probably preserves biomechanical functions, which has to be proven in future studies.     

Semi-Circumferential Decompression: Microsurgical Total en-bloc Ligamentum Flavectomy to Treat Lumbar Spinal Stenosis with Grade I Degenerative Spondylolisthesis

Background

To describe and assess clinical outcomes of the semi-circumferential decompression technique for microsurgical en-bloc total ligamentum flavectomy with preservation of the facet joint to treat the patients who have a lumbar spinal stenosis with degenerative spondylolisthesis.

Methods

We retrospectively analyzed the clinical and radiologic outcomes of 19 patients who have a spinal stenosis with Meyerding grade I degenerative spondylolisthesis. They were treated using the "semi-circumferential decompression" method. We evaluated improvements in back and radiating pain using a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). We also evaluated occurrence of spinal instability on radiological exam using percentage slip and slip angle.

Results

The mean VAS score for back pain decreased significantly from 6.3 to 4.3, although some patients had residual back pain. The mean VAS for radiating pain decreased significantly from 8.3 to 2.5. The ODI score improved significantly from 25.3 preoperatively to 10.8 postoperatively. No significant change in percentage slip was observed (10% preoperatively vs. 12.2% at the last follow-up). The dynamic percentage slip (gap in percentage slip between flexion and extension X-ray exams) did not change significantly (5.2% vs. 5.8%). Slip angle and dynamic slip angle did not change (3.2° and 8.2° vs. 3.6° and 9.2°, respectively).

Conclusions

The results suggested that semi-circumferential decompression is a clinically recommendable procedure that can improve pain. This procedure does not cause spinal instability when treating patients who have a spinal stenosis with degenerative spondylolisthesis.     

Four-level anterior cervical discectomies and cage-augmented fusion with and without fixation

Purpose

Anterior cervical decompression and fusion is a well-established procedure for the treatment of cervical spinal canal stenosis. In this study, we evaluated the necessity of spinal instrumentation after four-level anterior cervical decompression and cage fusion.

Methods

From January 2006 until August 2008, 25 patients (8 females and 17 males) (mean age 63.9 ± 7.9 years) suffering from spinal stenosis C3–C7 underwent anterior decompression and interbody fusion. The patients were divided into two groups. Four-level discectomy and cage fusion was performed in all patients. In group A including nine patients, posterior instrumentation with a lateral mass screw-rod system was added, while in group B including 16 patients, additional instrumentation was not performed. The mean duration of follow-up was 48.6 months (average 25–67 months).

Results

Clinically, the mean value for the Neck Disability Index improved from 40 ± 23.25 at presentation to 16.31 ± 15.09 at the final follow-up. The difference between the two groups was statistically not significant. Radiologically, the criteria for solid bony fusion were achieved successfully in all patients of group A, and in 87.5 % of patients in group B. The difference between the two groups was statistically not significant. The fused segment was then evaluated in the sagittal radiographs as regards the height and the lordosis angle. The loss in the height as well as the loss in the lordosis angle was more when posterior instrumentation was not added. However, the difference between the two groups was not statistically significant.

Conclusion

Stand-alone intersomatic cage fusion is an acceptable line of treatment for four-level cervical disc disease, both clinically and radiologically. Although the addition of posterior instrumentation yields better radiological results, the difference does not reach the statistical significance level.     

Efficacy of cranial electrotherapy stimulation for neuropathic pain following spinal cord injury: a multi-site randomized controlled trial with a secondary 6-month open-label phase

Background

Chronic pain is a significant problem for many individuals following spinal cord injury (SCI). Unfortunately, SCI-related neuropathic pain has proven to be largely refractory to analgesic medications and other available treatments. Cranial electrotherapy stimulation (CES) has been effective in managing some types of pain. It involves the application of a small amount of current through the head via ear clip electrodes.

Objective

Explore the effectiveness of CES for neuropathic pain in persons with SCI and chronic pain.

Study design

Multi-site, double-blind, sham-controlled study.

Participants

Adults with SCI and chronic neuropathic pain at or below the level of injury were randomized to receive active or sham CES.

Intervention

Application of active CES or sham CES 1 hour daily for 21 days. Six-month open-label phase to assess ‘as-needed’ CES use.

Outcome measures

Change in pre- to post-session pain ratings as well as change in pain intensity, pain interference, pain quality, pain beliefs and coping strategies, general physical and mental health status, depressive symptomatology, perceived stress, and anxiety pre- to post-treatment.

Results

The active group reported a significantly greater average decrease in pain during daily treatments than the sham group (Kruskal–Wallis chi-square = 4.70, P < 0.05). During the 21-day trial, there was a significant group × time interaction for only one outcome variable; the active group showed larger pre- to post-treatment decreases in pain interference than the sham group did (F = 8.50, P < 0.01, d = 0.59).

Conclusions

On average, CES appears to have provided a small but statistically significant improvement in pain intensity and pain interference with few troublesome side effects. Individual results varied from no pain relief to a great deal of relief.     

Titanium particles up-regulate the activity of matrix metalloproteinase-2 in human synovial cells

Purpose

Wear debris particle-induced osteolysis and subsequent aseptic loosening is one of the major causes of failure of total joint replacement. The purpose of this study was to investigate the effect of titanium implant material and inflammatory cytokines on human synovial cells and the development to osteolysis and aseptic loosening.

Methods

This study investigated the effect of titanium implant material on the ECM-degraded MMP-2 in human synovial cells and analyzed the contribution of synovial cells in osteolysis and aseptic loosening.

Results

When human synovial cells are exposed to titanium materials, MMP-2 activity is induced by 1.72 ± 0.14-fold with Ti disc and 3.95 ± 0.10-fold with Ti particles, compared with that of the controls, respectively. Inflammatory cytokines TNFα and IL-1β are also shown to induce MMP-2 activity by 3.65 ± 0.28-fold and 6.76 ± 0.28-fold, respectively. A combination of Ti particles and cytokines induces MMP-2 activities to a higher level (10.54 ± 0.45-fold). Inhibitors of various signal pathways involved in MMP-2 reverse Ti particle-induced MMP-2 activities.

Conclusions

Synovial cells surrounding the bone–prosthesis interface may contribute to production of MMP-2, and NFκB inhibitors may be explored as potential therapeutics to alleviate wear debris-induced osteolysis and aseptic loosening.     

Clinical outcome of lumbar spinal stenosis based on new classification according to hypertrophied ligamentum flavum

Background

The ligamentum flavum hypertrophy is considered to be one of the important causes of development of lumbar spinal stenosis (LSS). Several histologic and biologic mechanisms in hypertrophied flavum have proposed. However, no study that investigated the relationship between clinical outcome and ligamentum flavum hypertrophy has been published. The purpose of this study was to identify a new classification of LSS, in ligamentous and nonligamentous stenosis, according to the cutoff value of the area proportion of the ligamentum flavum in the spinal canal, and to assess the value of surgical and conservative treatments for LSS based on the classification of the ligamentous stenosis.