STUDY DESIGN: Comprehensive literature review. PURPOSE: To document the criteria for fusion utilized in these studies to determine if a consensus on the definition of a solid fusion exists. OVERVIEW OF LITERATURE: Numerous studies have reported on fusion rates following anterior cervical arthrodesis. There is a wide discrepancy in the fusion rates in these studies. While factors such as graft type, Instrumentation, and technique play a factor in fusion rate, another reason for the difference may be a result of differences in the definition of fusion following anterior cervical spine surgery. METHODS: A comprehensive English Medline literature review from 1966 to 2004 using the key words "anterior," "cervical," and "fusion" was performed. We divided these into two groups: newer studies done between 2000 and 2004, and earlier studies done between 1966 and 2000. These articles were then analyzed for the number of patients, follow-up period, graft type, and levels fused. Moreover, all of the articles were examined for their definition of fusion along with their fusion rate. RESULTS: In the earlier studies from 1966 to 2000, there was no consensus for what constituted a solid fusion. Only fifteen percent of these studies employed the most stringent definition of a solid fusion which was the presence of bridging bone and the absence of motion on flexion and extension radiographs. On the other hand, the later studies (2000 to 2004) used such a definition a majority (63%) of the time, suggesting that a consensus opinion for the definition of fusion is beginning to form. CONCLUSIONS: Our study suggests that over the past several years, a consensus definition of fusion is beginning to form. However, a large percentage of studies are still being published without using stringent fusion criteria. To that end, we recommend that all studies reporting on fusion rates use the most stringent criteria for solid fusion following anterior cervical spine surgery: the absence of motion on flexion/extension views and presence of bridging trabeculae on lateral x-rays. We believe that a universal adoption of such uniform criteria will help to standardize such studies and make it more possible to compare one study with another.
Adoption ; Arthrodesis ; Collodion ; Consensus ; Follow-Up Studies ; Hand ; Humans ; Pseudarthrosis ; Spine ; Transplants

STUDY DESIGN: Retrospective review of the results of somatosensory evoked potentials (SSEP) performed in cervical spine surgery. PURPOSE: To evaluate the utility of spinal cord monitoring during cervical spine surgery in a single surgeon's practice, based on how often it prompted an intraoperative intervention. OVERVIEW OF LITERATURE: Intraoperative monitoring during cervical spine surgery is not a universally accepted standard of care. This is due in part to the paucity of literature regarding the impact of monitoring on patient management or outcome. METHODS: SSEP for tibial, median, and ulnar nerves were monitored in 809 consecutive cervical spine operations performed by a single surgeon. The average patient age was 52 years (range, 2 to 88 years), with 472 males and 339 females. Cases were screened for significant degradation or loss of SSEP data. Specific attention was paid to 1) what interventions were performed in response to the SSEP degradation with subsequent improvement, and 2) whether SSEP changes corresponded with postoperative neurological deficits. RESULTS: Seventeen of 809 patients (2.1%) had SSEP degradation that met warning criteria and therefore prompted intervention. Release of shoulder tape (8) or traction (4) most often resulted in SSEP improvement. Failure of SSEP data to return to within acceptable limits of baseline was associated with neurological deficit (p=0.04). Two patients awoke with new postoperative neurological deficits, which resolved in 6 hours and 2 months respectively. Patients with ossification of the posterior longitudinal ligament (OPLL) were at seven-fold greater risk of intraoperative SSEP degradation. CONCLUSIONS: SSEP monitoring in this surgical population proved sensitive to perioperative factors which may increase the risk of postoperative neurologic deficit, and probably prevented neurological deficits in 15 of 809 patients (1.9%). Improvement in data following intervention appears to correlate well with unchanged neurologic status. Experience with intraoperative monitoring in this patient series has led to incorporation of these techniques as a standard of care in cervical spine surgeries performed by this surgeon.
Evoked Potentials, Somatosensory* ; Female ; Humans ; Longitudinal Ligaments ; Male ; Monitoring, Intraoperative ; Neurologic Manifestations ; Retrospective Studies ; Shoulder ; Spinal Cord ; Spine* ; Standard of Care ; Traction ; Ulnar Nerve

BACKGROUND: One of the characteristics of spinal stenosis is elastin degradation and fibrosis of the extracellular matrix of the ligamentum flavum. However, there have been no investigations to determine which biochemical factors cause these histologic changes. So we performed the current study to investigate the hypothesis that matrix metalloproteinases (MMPs), which possess the ability to cause extracellular matrix remodeling, may play a role as a mediator for this malady in the ligamentum flavum. METHODS: The ligamentum flavum specimens were surgically obtained from thirty patients with spinal stenosis, as well as from 30 control patients with a disc herniation. The extents of ligamentum flavum elastin degradation and fibrosis were graded (grade 0-4) with performing hematoxylin-eosin staining and Masson's trichrome staining, respectively. The localization of MMP-2 (gelatinase), MMP-3 (stromelysin) and MMP-13 (collagenase) within the ligamentum flavum tissue was determined by immunohistochemistry. The expressions of the active forms of MMP-2, MMP-3 and MMP-13 were determined by western blot analysis, and the blots were quantified using an imaging densitometer. The histologic and biochemical results were compared between the two conditions. RESULTS: Elastin degradation and fibrosis of the ligamentum flavum were significantly more severe in the spinal stenosis samples than that in the disc herniation samples (3.14 +/- 0.50 vs. 0.55 +/- 0.60, p < 0.001; 3.10 +/- 0.57 vs. 0.76 +/- 0.52, p < 0.001, respectively). The expressions of the active form of MMPs were identified in all the ligamentum flavums of the spinal stenosis and disc herniation patients. The expressions of active MMP-2 and MMP-13 were significantly higher in the spinal stenosis samples than that in the disc herniation samples (both p < 0.05). The expression of active MMP-3 was slightly higher in the spinal stenosis samples than that in the disc herniation samples, but the difference was not statistically significant (p = 0.131). MMP-2, -3, and -13 were positively stained on the ligamentum flavum fibroblasts. CONCLUSIONS: The current results suggest that the increased expression of active MMPs by the ligamentum flavum fibroblasts might be related to the elastin degradation and fibrosis of the ligamentum flavum in the patients who suffer with lumbar spinal stenosis.
Aged ; Blotting, Western ; Elastin/*metabolism ; Extracellular Matrix/metabolism/pathology ; Female ; Fibrosis ; Humans ; Immunohistochemistry ; Ligamentum Flavum/*metabolism/pathology ; *Lumbar Vertebrae ; Male ; Matrix Metalloproteinase 13/metabolism ; Matrix Metalloproteinase 2/metabolism ; Matrix Metalloproteinase 3/metabolism ; Matrix Metalloproteinases/*metabolism ; Middle Aged ; Spinal Stenosis/*metabolism/pathology

The present systematic review and meta-analysis was conducted to compare the safety and efficacy of the two approaches for primary spinal cord tumors (PSCTs) in adult patients (laminoplasty [LP] vs. laminectomy [LE]). LE is one of the most common procedures for PSCTs. Despite advantages of LP, it is not yet widely used in the neurosurgical community worldwide. The efficacy of LP vs. LE remains controversial. Adult patients over 18 years of age with PSCT at the level of the cervical, thoracic, and lumbar spine were included in the study. A literature search was performed in MEDLINE via PubMed, EMBASE, The Cochrane Library, and Google Scholar up to December 2021. Operation time, hospital stay, complications, and incidence of postoperative spinal deformity (kyphosis or scoliosis were extracted. A total of seven retrospective observational studies with 540 patients were included. There were no significant differences between LP and LE group in operation time (p =0.25) and complications (p =0.48). The LE group showed larger postoperative spinal deformity rate than the LP group (odds ratio, 0.47; 95% confidence interval [CI], 0.27−0.84; p =0.01). The LP group had a shorter hospital stay (standardized mean differences, −0.68; 95% CI, −1.03 to −0.34; p =0.0001) than the LE group. Both LP and LE have comparable operative times and total complications in the treatment of PSCT. LP was superior to LE in hospital stay and postoperative spinal deformity rate. However, these findings are limited by the very low quality of the available evidence. Randomized controlled trials are needed for further comparison.

Purpose: To analyze the cytokines that appear after a spinal cord injury in rats and to determine the agonists that regulate apoptosis. Materials and Methods: Sixty female Sprague-Dawley rats were anesthetized, and a laminectomy was performed at the 9th thoracic vertebra. The spinal cord injury was induced by dropping a 10 gm weight at a height of 20 mm. The subjects were divided into 5 groups. Group I was administered aminoguanidine, group II was administered GM-CSF, group III was administered riluzole, group IV was administered erythropoietin, and group V was administered methylprednisolone. A control group was administered normal saline. The results were assessed using the Tarlov motor grading method. In 1, 3, 5 and 7 days after the spinal cord injury, the rats were sacrificed and evaluated using the syringomyelic cavity size. Immunohistochemical staining for e-NOS and RT-PCR for XIAP were also performed. Results: Groups I, III, and V showed significantly different results in terms of the motor recovery and inhibition of increase in the syringomyelic cavity compared with the other groups (p<0.05). The e-NOS activity was observed in groups I, III, and V. The other groups showed almost no e-NOS activity. On the RT-PCR, groups I, III, and V showed significantly different results in terms of XIAP expression with time compared with the other groups. Conclusion: Steroids, NOS inhibitors and sodium channel inhibitors appear to be important factors for regulating apoptosis in the early stage of a spinal cord injury. Further study will be needed to develop new pharmaceuticals with synergic effects on spinal cord injuries.
Animals ; Apoptosis ; Cytokines ; Erythropoietin ; Female ; Granulocyte-Macrophage Colony-Stimulating Factor ; Humans ; Laminectomy ; Methylprednisolone ; Rats* ; Rats, Sprague-Dawley ; Riluzole ; Sodium Channel Blockers ; Spinal Cord Injuries ; Spine ; Steroids

STUDY DESIGN: Retrospective study. PURPOSE: To propose a new radiographic index for occipito-cervical instability. OVERVIEW OF LITERATURE: Symptomatic atlanto-occipital instability requires the fusion of the atlanto-occipital joint. However, measurements of occipito-cervical translation using the Wiesel-Rothman technique, Power's ratio, and basion-axial interval are unreliable because the radiologic landmarks in the occipito-cervical junction lack clarity in radiography. METHODS: One hundred four asymptomatic subjects were evaluated with lateral cervical radiographs in neutral, flexion and extension. They were stratified by age and included 52 young (20-29 years) and 52 middle-aged adults (50-59 years). The four radiographic reference points were posterior edge of hard palate (hard palate), posteroinferior corner of the most posterior upper molar tooth (molar), posteroinferior corner of the C1 anterior ring (posterior C1), and posteroinferior corner of the C2 vertebral body (posterior C2). The distance from posterior C1 and posterior C2 to the above anatomical landmarks was measured to calculate the range of motion (ROM) on dynamic radiographs. To determine the difference between the two age groups, unpaired t-tests were used. The statistical significance level was set at p<0.05. RESULTS: The ROM was 4.8+/-7.3 mm between the hard palate and the posterior C1, 9.9+/-10.2 mm between the hard palate and the posterior C2, 1.7+/-7.2 mm between the molar to the posterior C1, and 10.4+/-12.1 mm between the molar to the posterior C2. There was no statistically significant difference for the ROM between the young- and the middle-aged groups. The intra-observer reliability for new radiographic index was good. The inter-observer reliability for the ROM measured by the hard palate was low, but was better than that by the molar. CONCLUSIONS: ROM measured by the hard palate might be a useful new radiographic index in cases of occipito-cervical instability.
Adult ; Atlanto-Occipital Joint ; Humans ; Molar ; Palate, Hard ; Radiography ; Range of Motion, Articular ; Retrospective Studies ; Tooth

PURPOSE: There have been a few previous reports regarding the distances between the medial borders of the longus colli to expose the disc space. However, to our knowledge, there are no reports concerning longus colli dissection to expose the uncinate processes. This study was undertaken to assess the surgical relationship between the longus colli muscle and the uncinate process in the cervical spine. MATERIALS AND METHODS: This study included 120 Korean patients randomly selected from 333 who had cervical spine MRIs and CTs from January 2003 to October 2013. They consisted of 60 males and 60 females. Each group was subdivided into six groups by age from 20 to 70 years or more. We measured three parameters on MRIs from C3 to T1: left and right longus colli distance and inter-longus colli distance. We also measured three parameters on CT: left and right uncinate distance and inter-uncinate distance. RESULTS: The longus colli distances, uncinate distances, and inter-uncinate distances increased from C3 to T1. The inter-longus colli distances increased from C3 to C7. There was no difference in longus colli distances and uncinate distances between males and females. There was no difference in the six parameters for the different age groups. CONCLUSION: Although approximate guidelines, we recommend the longus colli be dissected approximately 5 mm at C3-5, 6 mm at C5-6, 7 mm at C6-7, and 8 mm at C7-T1 to expose the uncinate process to its lateral edge.
Adult ; Aged ; Cervical Vertebrae/*anatomy & histology/diagnostic imaging/*surgery ; Dissection ; Female ; Humans ; Male ; Middle Aged ; Neck Muscles/*anatomy & histology/diagnostic imaging/*surgery ; Random Allocation ; Young Adult

STUDY DESIGN: Retrospective study. PURPOSE: To investigate safety profile of open door laminoplasty plates. OVERVIEW OF LITERATURE: Few reports have documented potential complications related to the use of cervical laminoplasty plates. METHODS: Records and radiographs of consecutive plated laminoplasty patients of one academic surgeon were analyzed. Group 1 had screw back-out, defined as change in screw position, and group 2 did not. RESULTS: Forty-two patients (mean age, 56.9) underwent "open-door" cervical laminoplasty using 165 plates. Mean follow-up was 24 months (range, 12-49 months). Mean Nurick grade improved from 2.1 to 0.9 postoperatively. Cervical lordosis (C2-7) was 12.1degrees preoperatively and 10.0degrees postoperatively. Range-of-motion was 27.0degrees preoperatively and 23.4degrees postoperatively. Partial screw back-out was noted in 27 of 165 plates (16.4%) and in 34 of 660 screws (5.2%). Of the 34 screws, 27 (79.4%) were at either the most cranial (12/27, 44.4%) or the most caudal (15/27, 55.5%) level. Cranially, 11/12 screws (91.7%) had back-out. Caudally, 9/15 lateral mass screws (60.0%) backed-out versus 6 laminar screws (40.0%). Of the 22 patients with screw back-out, 15 (68.2%) occurred <3 months postoperative and 6 (27.3%) occurred 4-12 months postoperative. No statistical differences were found between group 1 and 2 for age, gender, preoperative and postoperative lordosis, focal sagittal alignment, range-of-motion, or Nurick grade. Despite screw backout in 22 patients, there were no plate dislodgements, laminoplasty closure, or neurological deterioration. CONCLUSIONS: Although screw back-out may occur with the use of cervical laminoplasty plates, the use of these plates without a bone block appears to be safe and reliable. As screw back-out is most common at the cranial and caudal ends of the laminoplasty, we recommend using the maximum number of screws (typically 2 for the lateral mass and 2 for the spinous process) at these levels to secure the plate to the bone.
Animals ; Follow-Up Studies ; Humans ; Lordosis ; Retrospective Studies

STUDY DESIGN: Retrospective study. PURPOSE: To identify the prevalence of severe headache occurring after cervical posterior surgical fixation (PSF) and to evaluate the clinical and radiological findings associated with severe headache after surgery. OVERVIEW OF LITERATURE: Several studies have reported on the axial pain after cervical surgery. However, to our knowledge, the incidence of severe headache after cervical PSF has not been elucidated. METHODS: The medical records and radiological assessment of patients who underwent surgical treatment from August 2002 to May 2012 were reviewed to identify the prevalence and risk factors for severe headaches occurring following PSF from C2 distally. Neck disability index scores (NDI) (the item for neck pain), the type of C2 screw, number of cervical fused levels (1–6), and smoking habit were calculated preoperatively and postoperatively. In addition, radiological parameters (T1 slope angle, C1/2 angle, C2–7 Cobb angle, C2–7 sagittal vertical axis and C1-implant distance) were assessed for all patients. Severe headache was defined as a high NDI headache score (>4 out of 5). RESULTS: Eighty-two patients met the inclusion criteria. The mean age was 59.2 years (range, 21–78 years), and the mean number of fused levels was 5.1. The mean follow-up period was 2.9 years (range, 1–10.9 years). While only one severe headache occurred de novo postoperatively in a patient in the C3 or C4 distally group (total 30 patients, average age of 50.2 years), 11 patients in the C2 distally group (p=0.04) had severe headache occur postoperatively. The radiological parameters were not significantly different between the postoperative milder headache and severe headache (SH) groups. The SH group had a significantly higher preoperative NDI score (neck pain) (p<0.01). CONCLUSIONS: Newly occurring severe headaches can occur in 18% of patients after PSF from C2 distally. The patients with newly occurring severe headaches had significantly higher preoperative NDI score (neck pain).
Follow-Up Studies ; Headache* ; Humans ; Incidence ; Medical Records ; Neck ; Prevalence ; Retrospective Studies ; Risk Factors ; Smoke ; Smoking

PURPOSE: Herniated nucleus pulposus fragments are recognized by the immune system as a foreign-body, which results in an autoimmune reaction. Human activation-inducible tumor necrosis factor receptor (AITR) and its ligand, AITRL, are important costimulatory molecules in the pathogenesis of autoimmune diseases. Despite the importance of these costimulatory molecules in autoimmune disease, their role in the autoimmune reaction to herniated disc fragments has yet to be explored. The purpose of the present study is to investigate whether the overexpression of AITR and AITRL might be associated with lumbar disc herniation. MATERIALS AND METHODS: The study population consisted of 20 symptomatic lumbar disc herniation patients. Ten macroscopically normal control discs were obtained from patients with spinal fractures managed with anterior procedures that involved a discectomy. Peripheral blood samples from both the study patients and controls were collected. The expression levels of AITR and AITRL were investigated by flow cytometric analysis, confocal laser scanning microscopy, immunohistochemistry and by reverse transcriptase-polymerase chain reaction (RT-PCR). The soluble AITR and AITRL serum levels were measured by an enzyme-linked immunosorbent assay. RESULTS: Flow cytometric analysis revealed significantly higher levels of both AITR and AITRL in the lumbar disc herniation patients than in the controls. The AITRL expression levels were also increased in patients with lumbar disc herniation, shown by using confocal laser scanning microscopy, immunohisto-chemistry, and RT-PCR. Finally, soluble AITR and AITRL were elevated in the patients with lumbar disc herniations. CONCLUSION: The AITR and AITRL are increased in both the herniated disc tissue and the peripheral blood of patients with lumbar disc herniation.
Adult ; Female ; Flow Cytometry ; Humans ; Immunohistochemistry ; Interleukins/blood ; Intervertebral Disk Displacement/*immunology ; *Lumbar Vertebrae ; Male ; Microscopy, Confocal ; Middle Aged ; Receptors, Nerve Growth Factor/*blood ; Receptors, Tumor Necrosis Factor/*blood ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Necrosis Factor-alpha/blood ; Tumor Necrosis Factors/*blood