How Do Patients With Predominant Neck Pain Improve After Anterior Cervical Discectomy and Fusion for Cervical Radiculopathy?

BACKGROUND: The presence of predominant pain in the arm vs the neck as a predictor of postoperative outcomes after anterior cervical discectomy and fusion (ACDF) has been seldom reported; therefore, the purpose of this study was to determine whether patients with predominant neck pain improve after surgery compared to patients with predominant arm pain or those with mixed symptoms in patients undergoing ACDF for radiculopathy. METHODS: A retrospective cohort study was conducted on patients who underwent ACDF at a single center from 2016 to 2018. Patients were split into groups based on preoperative neck and arm pain scores: neck (N) pain dominant group (visual analog scale [VAS] neck ≥ VAS arm by 1.0 point); neutral group (VAS neck < VAS arm by 1.0 point); or arm (A) pain dominant group (VAS arm ≥ VAS neck by 1.0 point), using a threshold difference of 1.0 point. Subsequently, individuals were substratified into 2 groups based on the arm to neck pain ratio (ANR): non-arm pain dominant defined as ANR ≤1.0 and arm pain dominant (APD) defined as ANR >1.0. Patient-reported outcome measurements including Neck Disability Index (NDI), Physical Component Score-12, and Mental Component Score (MCS-12) were compared between groups. RESULTS: No significant differences between groups when stratifying patients using a threshold difference of 1.0 point. When stratifying patients using the ANR, those in the APD group had significantly higher postoperative MCS-12 (P = 0.008) and NDI (P = 0.011) scores. In addition, the APD group showed a greater magnitude of improvement for MCS-12 and NDI scores (P = 0.043 and P = 0.038, respectively). Multiple linear regression showed that the A and the APD groups were both independent predictors of improvement in NDI. CONCLUSION: Patients with dominant arm pain showed significantly greater improvement in terms of MCS-12 and NDI scores compared to patients with dominant neck pain. CLINICAL RELEVANCE: To compare the impact of ACDF on arm and neck pain in the context of cervical radiculopathy using patient-reported outcome measures as an objective measurement.

Does Cervical Spondylolisthesis Influence Patient-Reported Outcomes After Anterior Cervical Discectomy and Fusion Surgery?

BACKGROUND: No prior work has explored whether the presence of degenerative spondylolisthesis impacts patient-reported outcome measurements (PROMs) after an anterior cervical discectomy and fusion (ACDF); therefore, the goal of the current study was to determine whether the presence of a spondylolisthesis affects PROMs after an ACDF. METHODS: A retrospective cohort study was conducted on patients over the age of 18 who underwent a 1- or 2-level ACDF. All patients received preoperative standing lateral x-rays and were placed into 1 of 2 groups based on the presence of cervical spondylolisthesis from C2-T1: (1) no spondylolisthesis (NS) group or (2) spondylolisthesis (S) group. Preoperative, postoperative, and delta (postoperative minus preoperative) were recorded and compared between groups via univariate and multivariate analysis. Outcomes reported were the Physical Component Scores of the Short Form-12 (PCS-12), the Mental Component Scores of the Short Form-12 (MCS-12), the Neck Disability Index (NDI), and visual analog scale (VAS) Arm/Neck. RESULTS: A total of 202 patients were included in the final analysis with 154 in the NS group and 48 in the S group. Both patient cohorts reported significant postoperative improvement in PCS-12, NDI, and VAS Arm/Neck. When comparing outcome scores between groups, only MCS-12 delta scores were different between groups, with the S group exhibiting a greater mean delta score (8.3 vs 1.3, P = 0.024) than the NS group after ACDF. Multiple linear regression analysis indicated having spondylolisthesis at baseline was a significant predictor of greater change in MCS-12 than the NS group (ß = 4.841; 95% CI, 0.876, 8.805; P = 0.017). CONCLUSION: Both groups demonstrated significant postoperative improvement in PCS-12, NDI, or VAS Neck/Arm pain scores with no significant differences between groups. Patients with spondylolisthesis were found to have significantly greater improvement scores in MCS-12 scoring than those without spondylolisthesis after ACDF surgery.

Facet Joint Violation During Percutaneous Pedicle Screw Placement: A Comparison of Two Techniques.

STUDY DESIGN: A comparative study of facet joint violation (FJV) using two percutaneous surgical techniques. OBJECTIVE: To compare the rate of iatrogenic FJV and medial pedicle wall breach between two methods of percutaneous pedicle screw instrumentation in the thoracic and lumbar spine. SUMMARY OF BACKGROUND DATA: Variable iatrogenic damage to the facet joints has been reported to occur with percutaneous pedicle screw techniques, compared with the open approach, which has been associated with adjacent segment disease. Technical variations of percutaneous pedicle screw placement may pose different risks to the facet joint. METHODS: Attending spine surgeons percutaneously placed pedicle screws in seven human cadaveric spines from T2 to L5. At each level, screws were instrumented on one side using the 9 or 3 o'clock reference point of the pedicle on the posteroanterior view with a lateral-to-medial trajectory (LMT) and on the contralateral side using the center of the pedicle with an owl's eye trajectory (OET). Postoperative screw placement was assessed with computed tomography and then open cadaveric dissection. Outcome measures included FJV and medial pedicle wall breach. RESULTS: Overall, 17 of 105 screws placed with an LMT versus 49 of 105 screws placed with an OET violated or abutted the facet joint (P <0.0001). This significant difference was observed at the thoracic (T2-T10), thoracolumbar (T11-L1), and lumbar (L2-L5) levels (P = 0.003, 0.035, and 0.018, respectively). Medial pedicle wall breach occurred with 11 LMT screws and seven OET screws (P = 0.077), and no breach was considered critical. CONCLUSION: A significantly higher FJV rate was observed using the OET versus the LMT in the thoracic, thoracolumbar, and lumbar spine. No statistically significant differences in medial pedicle wall breach occurred between the techniques. Thus, the LMT of minimally invasive pedicle screw fixation may reduce iatrogenic damage to the facet joints. LEVEL OF EVIDENCE: 3.

Correlation of C2 fractures and vertebral artery injury.

STUDY DESIGN: Retrospective review of prospectively collected data. SUMMARY OF BACKGROUND DATA: Vertebral artery injuries (VAI) occur commonly after cervical spine trauma. No study has yet examined the association between VAI and specific variants of C2 fractures. OBJECTIVE: To evaluate the incidence of VAI (as defined by magnetic resonance imaging/angiography [MRI/A]) in subtypes of C2 fractures. To define the association between the incidence, morphology, and severity of C2 fractures, based on fracture angulation and comminution, and the occurrence of VAI. METHODS: Patients admitted to the hospital with C2 fractures between October 2006 and December 2008 to a tertiary care referral center were identified through a prospectively maintained database. Computed tomography (CT) and MRI/A studies were individually reviewed to evaluate the specific C2 fracture type and the occurrence of VAI. Fracture displacement and angulation were measured. Incidence of VAI was compared between different types and subtypes of C2 fractures. The effects of displacement and angulation of the fracture, morphology of foramen transversarium fracture, patient age, and patient gender on VAI were also analyzed. RESULTS: One hundred one patients were identified with C2 fractures that met inclusion criteria, and 18 (17.8%) had VAI by MRI/A. There was no correlation between fracture types and VAI. However, in subtype analysis, there was a correlation of VAI with traumatic spondylolisthesis of axis (TSA) and greater degree of angulation (P = 0.0023), communition fracture (P = 0.0341), and presence of bone fragment(s) within the foramen transversarium (P = 0.0075). Multivariate logistic regression indicated that age, gender and the presence of fragments within foramen transversarium were associated with greater risk of VAI. CONCLUSION: Vertebral artery injuries are more likely to occur in C2 fractures with comminuted fractures involving the foramen transversarium, with fractures manifesting bony fragment(s) within the foramen transversarium, or with fractures having greater angulation. These risk factors should be considered when a patient presents with isolated axis fracture.

Cytokine assay of the epidural space lavage in patients with lumbar intervertebral disk herniation and radiculopathy.

INTRODUCTION: Lumbar disk herniation may result in a radiculopathic pattern of symptoms. Consideration for a primary biochemical inducement of pain over a mechanical mechanism is a contemporary topic of spinal research. However, the exact pathomechanism by which a degenerative intervertebral disk leads to neural inflammation and pain has not been determined. Using modern techniques of chemical analysis, biochemical markers can be identified which participate in the degenerative cascade, and possibly with the onset of pain. The purpose of this research is to identify potential biochemical markers through a novel technique of epidural space lavage that may be helpful in understanding the pathogeneses of pain in the presence of intervertebral disk degeneration and herniation. METHODS: Fifty consecutive patients with acute radiculopathy secondary to a symptomatic herniated lumbar intervertebral disk or spinal stenosis, and who were indicated for epidural steroid injection were identified. Additionally, 3 volunteers with no history of back pain or radiculopathy volunteered to undergo epidural lavage. After needle insertion, a lavage followed by fluid aspiration of the epidural space at the level of the disc herniation, in the case of the symptomatic patients, was performed using normal saline, before the instillation of corticosteroids. The fluid samples were frozen at -20 degrees C until analysis. A biochemical evaluation for a battery of cytokines was undertaken (IL-1beta, IL-1ra, IL-2, IL-2R, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p40, IL-13, IL-15, IL-17, TNF-alpha, IFN-alpha, IFN-gamma, GM-CSF, MIP-1alpha, MIP-1beta, IP-10, MIG, Eotaxin, RANTES, and MCP-1, and neuropeptides) using high-resolution multiplex bead immunoassays and enzyme-linked immunosorbent assay (ELISA). Additionally, polyacrylamide gel electrophoresis was carried out to verify the presence of serum proteins. RESULTS: Despite the presence of amino acids/serum proteins in the epidural lavage fluid, none of the aforementioned mediators were isolated in a quantifiable concentration using the ELISA techniques with >5 pg/mL resolution. DISCUSSION: The current proteomics array technology was not able to detect critical levels of biochemical markers present in the epidural space through the mentioned lavage technique. This lack of detection could be due to the absence of the factors in this environment or the inability of the technique to obtain or detect factors which may be present. CONCLUSION: Although a novel approach, the current study was unable to identify the presence of a series of inflammatory peptides in the epidural lavage of patients with symptomatic radicular pain due to herniated disc disease. We recommend alternative experimental designs than the one we pursued for definitively identifying potential sources of pain generators.

Demineralized bone matrix gelatin as scaffold for osteochondral tissue engineering.

To develop a single-unit osteochondral tissue with demineralized bone matrix gelatin (BMG), rabbit chondrocytes were cultured on demineralized bone matrix gelatin for 6 weeks. The engineered osteochondral tissue was characterized with histology, immunolocalization, TEM, SEM, biochemical assay, and gene expression analysis. About 1.3mm viable neo-cartilage was produced on demineralized BMG. RT-PCR, immunohistochemistry, TEM, biochemical assay, and histology revealed hyaline-like cartilage with zonal layers, intense type II collagen expression, and abundant proteoglycan content formed upon BMG compared with normal cartilage. But hydroxyproline content and type I collagen gene and protein expressions were significantly lower. We consider engineering cartilage tissue with chondrocytes cultured on allogenic demineralized BMG is a good approach for osteochondral tissue engineering.

Modulation of chondrocytic properties of fat-derived mesenchymal cells in co-cultures with nucleus pulposus.

Human subcutaneous fat-derived mesenchymal cells recently have been shown to have the potential to differentiate in vitro into a variety of cell types, including adipocytes, osteoblasts, chondrocytes, and myoblasts. This effect suggests that fat tissue may serve as an abundant and easily acquired source of multipotent cells for tissue engineering. The multipotential characteristics of fat-derived mesenchymal cells from the inguinial fat pad of rabbit have not been clearly defined. In this study we have isolated a population of mesenchymal cells from inguinal fat from adult New Zealand white rabbits. The cells that were maintained under various differentiation conditions were shown to differentiate in vitro into adipocytes, osteoblasts, or chondrocytes; this differentiation was demonstrated using gene expression for tissue-specific proteins. We also co-cultured the cells with intervertebral disk tissue from the nucleus pulpous or from the annulus fibrosus. The fat-derived cells co-cultured with nucleus pulposus showed an increase in expression of type II collagen and aggrecan genes, compared with cells in alginate alone and cells co-cultured with annulus fibrosus. The data suggest that the fat-derived mesenchymal cells responded to soluble mediators from the disk. Future studies on intervertebral disk reconstruction could be based on our findings with fat-derived multipotential cells from the inguinal region of the rabbit that were co-cultured with disk tissue and may prove useful in tissue engineering strategies.

Analysis of patient variables affecting neurologic outcome after traumatic cervical facet dislocation.

BACKGROUND CONTEXT: Traumatic cervical facet dislocation accounts for a disproportionate rate of neurologic disability. The relative importance of patient and management variables, including the timing of spinal reduction, in ultimate neurologic outcome has not been well defined. PURPOSE: To analyze data from a cohort of patients sustaining traumatic cervical facet dislocation to determine the relative importance of several patient and management variables in neurologic recovery after injury. STUDY DESIGN/SETTING: A retrospective study was conducted at a major referral center for spinal-cord-injured patients. PATIENT SAMPLE: Forty-five patients sustaining traumatic cervical facet dislocation. OUTCOME MEASURES: Using improvement in American Spinal Injury Association (ASIA) motor score as the primary outcome measure, patient data were used to construct a statistical model allowing the analysis of several clinically relevant variables. METHODS: The records of patients sustaining a traumatic cervical facet dislocation over a 5-year period were reviewed. Clinical data were collected for all patients with adequate follow-up. The data were used to construct a statistical model designed to analyze the contribution of the variables age, gender, time to reduction of the spine and initial motor score to neurologic improvement (the outcome measure). In addition, the effect of variable interaction was studied. RESULTS: Most patients demonstrated neurologic improvement over the course of follow-up after cervical facet dislocation. For this data set, the variables age and initial motor score were significantly associated with neurologic improvement. However, time to reduction of the spine did not demonstrate a significant independent relationship to neurologic outcome. No significant interaction was found between patient age or gender and the time to reduction with regard to predicting neurologic recovery. CONCLUSION: The present study uses a statistical model to determine the relative importance of clinically relevant variables for a population of patients after traumatic cervical facet dislocation. This model confirms the clinical impression that younger patients with lesser degrees of neurologic injury tend to achieve the best neurologic recovery after a traumatic facet dislocation. Although a strong benefit from earlier spinal column reduction did not emerge from the present data set, additional study is needed to define those patients who would benefit from immediate reduction of the spinal column.

A fibronectin fragment stimulates intervertebral disc degeneration in vivo.

STUDY DESIGN: A radiographic, histologic, biochemical, and gene expression study was conducted in vivo in a rabbit model to determine the effect of injection of the N-terminal 30 kDa fibronectin fragment (Fn-f) into the intervertebral disc along with various control substances. OBJECTIVE: To determine if the Fn-f is able to induce disc degeneration in vivo. SUMMARY OF BACKGROUND DATA: Animal models of disc degeneration are crucial to defining the molecular events involved in disc degeneration. Although spontaneous and induced models of disc degeneration have been described, none is ideal for molecular studies. A better understanding of disc degeneration at the molecular level is necessary to promote rational design of therapies for degenerative disc disease. MATERIALS AND METHODS: Thirty-one New Zealand white rabbits underwent injection of Fn-f and control substances into the central region of separate lumbar discs using a fine needle. Euthanasia was performed at the 2-, 4-, 8-, 12-, and 16-week time points and the discs were examined radiographically, histologically, biochemically, and with gene expression. RESULTS: Radiographs demonstrated anterior osteophyte formation at Fn-f-injected disc spaces by the 12-week time point. Histology demonstrated a progressive loss of the normal architecture of the nucleus pulposus and anulus fibrosus over the 16-week study period. A progressive loss of proteoglycans was documented using GAG assay but total collagen did not appear to change appreciably. Gene expression studies demonstrated a significant down-regulation of both aggrecan and type II collagen mRNA between the 8- and 16-week time points. CONCLUSION: Fn-f appears to induce a progressive degenerative process within the intervertebral disc after injection that resembles degenerative disc disease. This model has several significant advantages for the study of disc degeneration at the molecular level. Further studies are warranted to elucidate the mechanism and molecular events associated with Fn-f-mediated disc degeneration.