Missed cervical disc bulges diagnosed with kinematic magnetic resonance imaging.

PURPOSE: To determine if adding flexion and extension MRI studies to the traditional neutral views would be beneficial in the diagnosis of cervical disc bulges. METHODS: Five hundred patients underwent MRI in neutral, flexion and extension positions. The images were analyzed using computer software to objectively quantify the amount of disc bulge. RESULTS: Compared to the neutral position, cervical disc bulges were significantly increased in the extension position (P < 0.05), but on flexion position, there was no significant difference (P > 0.05). For patients without or <3 mm of disc bulge in neutral, 2.97% demonstrated an increase in bulge to ≥3 mm bulge in flexion, and 16.41% demonstrated an increase to ≥3 mm bulge in extension. For patients in the neutral view that had a baseline disc bulge of 3-5 mm, 3.73% had increased bulges to ≥5 mm in flexion and 11.57% had increased bulges to ≥5 mm in extension. CONCLUSION: A significant increase in the degree of cervical disc bulge was found by examining extension views when compared with neutral views alone. Kinematic MRI views provide valuable added information, especially in situations where symptomatic radiculopathy is present without any abnormalities demonstrated on traditional neutral MRI.

Complications Associated with Peripheral Nerve Blocks.

Outpatient orthopedic surgery is gradually becoming the standard across the country, as it has been found to significantly lower costs without compromising patient care. Peripheral nerve blocks (PNBs) are largely what have made this transition possible by providing patients excellent pain control in the immediate postoperative period. However, with the increasing use of PNBs, it is important to recognize that they are not without complications. Although rare, these complications can cause patients a significant amount of morbidity. It is important for surgeons to know the risks of peripheral nerve blocks and to inform their patients.

Dynamic Evaluation of the Cervical Spine and the Spinal Cord of Symptomatic Patients Using a Kinetic Magnetic Resonance Imaging Technique.

PURPOSE: The purpose of this study was to examine the movement of the spinal cord and its relationship to the spinal canal in patients with mild spondylosis using kinetic magnetic resonance imaging (kMRI). METHODS: Weight-bearing, multiposition kMRI was performed on symptomatic patients through a full range of flexion-extension. A total of 52 study patients were selected based on the C2-C7 Cobb angle of sagittal alignment: lordotic (from 30 to 45 degrees). We evaluated dynamic changes in different parameters from flexion-extension: spinal canal diameter (CD), spinal cord diameter (SCD), space available for the cord, anterior space available for the cord (ASAC), posterior space available for the cord (PSAC), average distance between the anterior canal and the cord (d-value), and global angle for the spinal canal and cord. RESULTS: The CD tended to decrease from flexion to extension from C3/C4 to C6/C7, however, there were no significant differences at the proximal and distal levels, C2/C3 and C7/T1. There were no significant differences of SCD between different postures. The SCD tended to decrease from C2/C3 to C7/T1. The ASAC followed the same pattern as CD-values. The ASAC was narrowest at C4/C5 and C5/C6. The PSAC tended to increase from C2/C3 to C7/T1. The spinal cord shifted anteriorly with extension and posteriorly with flexion. In addition, the spinal cord maintained its curve with the movement. CONCLUSIONS: The kinematics of spinal cord motion may be associated with the pathogenesis of cervical spondylotic myelopathy. However, the spinal cord maintains its curve with position changes. Consequently, different motions of the cervical spine may affect spinal cord migration and cause changes in ASAC and PSAC.

Scaphoid and Lunate Dislocation with Complete Soft-Tissue Avulsion: A Case Report.

CASE: We describe an intercarpal dislocation with proximal and rotatory displacement of the lunate and with volar and radial dislocation of the scaphoid; both bones were stripped of soft tissue. Treatment involved ORIF (open reduction and internal fixation). Three years postoperatively, the patient had a DASH (Disabilities of the Arm, Shoulder and Hand) score of 10, equivalent grip strength and 50% wrist palmar flexion and 98% wrist dorsiflexion compared with the uninjured side, and radiographic evidence of posttraumatic arthritis. CONCLUSION: Treatment of simultaneous divergent lunate and scaphoid dislocation with loss of nearly all soft-tissue attachments and vascular supply by means of ORIF and repair of soft-tissue structures can result in a favorable intermediate-term functional outcome and may be superior to other salvage procedures such as proximal row carpectomy.

Kinematic analysis of diseased and adjacent segments in degenerative lumbar spondylolisthesis.

BACKGROUND CONTEXT: Degenerative spondylolisthesis is a common pathologic condition that leads to lumbar instability and significant clinical symptoms. The effect of this pathology on adjacent lumbar motion segments, however, has not yet been studied. PURPOSE: To characterize the motion characteristics of lumbar degenerative spondylolisthesis at both the diseased and adjacent levels in patients with low-grade, single-level lumbar degenerative spondylolisthesis using kinetic magnetic resonance imaging (kMRI). STUDY DESIGN: Retrospective study of patient kMRIs. PATIENT SAMPLE: One-hundred twelve patient MRIs with low-grade, single-level lumbar spondylolisthesis were included. OUTCOME MEASURES: Angular and translational motion. METHODS: This study compared 112 patients diagnosed with low-grade (Grade 1 or 2), single-level lumbar degenerative spondylolisthesis at L3-L4, L4-L5, or L5-S1 with 296 control patients without spondylolisthesis. Angular and translational motion were measured using patient kMRIs. The level of slip was graded according to the Meyerding classification system, and disc degeneration was classified according to the Pfirrmann system. Instability was defined as translational motion greater than 4 mm. RESULTS: Lumbar hypomobility was often present regardless of the level of degenerative spondylolisthesis. A slip at L3-L4 resulted in the largest decrease in lumbar range of motion. Instability at the diseased level was most common at L3-L4 (36%), followed by L5-S1 (31%) and L4-L5 (30%). Instability at the adjacent segments was most frequent at L4-L5 (49%), followed by L5-S1 (34%) and L3-L4 (23%). Patients with stable spondylolisthesis generally had decreased angular motion at all lumbar levels. Translational motion at the diseased level was consistently increased. Disc degeneration was significantly greater at the level of slip for the L3-L4 and L4-L5 spondylolisthesis groups and equal to the control group in the L5-S1 group. There was no significant difference in disc degeneration at adjacent segments in L3-L4 and L4-L5 degenerative spondylolisthesis patients, but there was a significant decrease with an L5-S1 slip. CONCLUSIONS: There were a similar percentage of patients in each degenerative spondylolisthesis group with lumbar instability. Angular motion decreased at the diseased level with L3-L4 and L5-S1 spondylolisthesis, but increased with L4-L5 spondylolisthesis. Translational motion, however, increased at the diseased level in all three groups. There was compensatory hypermobility at adjacent levels in patients with unstable spondylolisthesis at L3-L4 and L4-L5, but not at L5-S1.

Motion characteristics and related factors of Modic changes in the lumbar spine.

OBJECT Most studies of Modic changes (MCs) have focused on investigating the relationship between MCs and lowback pain, whereas the kinematic characteristics and degenerative disc disease associated with MCs are not well understood. To the authors' knowledge, no previous study has reported on the kinematics of MCs. The purpose of this study was to elucidate the relationship of MCs to segmental motion and degenerative disc disease. METHODS Four hundred fifty symptomatic patients underwent weight-bearing lumbar kinematic MRI in the neutral, flexion, and extension positions. Segmental displacement and intervertebral angles were measured in 3 positions using computer analysis software. Modic changes, disc degeneration, disc bulging, spondylolisthesis, angular motion, and translational motion were recorded, and the relationship of MCs to these factors was analyzed using a logistic regression model. To control the influence of disc degeneration on segmental motion, angular and translational motion were analyzed according to mild and severe disc degeneration stages. The motion characteristics and disc degeneration among types of MCs were also evaluated. RESULTS Multivariate analysis revealed that age, disc degeneration, angular motion, and translational motion were factors significantly related to MCs. In the severe disc degeneration stage, a significant decrease of angular motion and significant increase of translational motion were found in segments with MCs, indicating that a disorder of the endplate had an additional effect on segmental motion. Disc degeneration increased and angular motion decreased significantly and gradually as the type of MC increased. Translational motion was significantly increased with Type 2 MCs. CONCLUSIONS Age, disc degeneration, angular motion, and translational motion were significantly linked to MCs in the lumbar spine. The translational motion of lumbar segments increased with Type 2 MCs, whereas angular motion decreased as the type of MC increased, indicating that Type 2 MCs may have translational instability likely due to degenerative changes. A disorder of the endplates could play an important role in spinal instability.

Comparison of a novel oxysterol molecule and rhBMP2 fusion rates in a rabbit posterolateral lumbar spine model.

BACKGROUND CONTEXT: The nonunion rate after lumbar spinal fusion is as high as 25%. Recombinant human bone morphogenetic protein 2 (rhBMP2) has been used as a biological adjunct to promote bony fusion. However, recently there have been concerns about BMP2. Oxysterol 133 (Oxy133) has been shown to promote excellent fusion rates in rodent lumbar spine models and offers a potential alternative to rhBMP2. PURPOSE: The purpose of this study was to compare the fusion rate of rhBMP2 and Oxy133 in a randomized controlled trial using a posterolateral lumbar rabbit spinal fusion model. STUDY DESIGN: This was a randomized control animal study. METHODS: Twenty-four male adult white New Zealand rabbits (3-3.5 kg) underwent bilateral posterolateral lumbar spinal fusion at L4-L5. Rabbits were divided into four groups: control (A), 30-µg rhBMP2 (B), 20-mg Oxy133 (C), and 60-mg Oxy133 (D). At 4 weeks, fusion was evaluated by fluoroscopy, and at 8 weeks, the rabbits were sacrificed and fusion was evaluated radiographically, by manual palpation, and with microcomputed tomography. RESULTS: Fusion rates by radiographic analysis at 8 weeks were Group A, 40.0%; Group B, 91.7%; Group C, 91.7%; and Group D, 100%. Evaluation of fusion masses by manual palpation of excised spines after sacrifice showed the following fusion rates: Group A, 0%; Group B, 83.3%; Group C, 83.3%; and Group D, 90%. Microcomputed tomography scanning confirmed these findings. CONCLUSIONS: These findings in a rabbit model demonstrate that both 20- and 60-mg Oxy133 doses promote fusion that is equivalent to fusion induced by 30-µg rhBMP2 and significantly greater than the control group. The present findings confirm that Oxy133 is a promising candidate for therapeutic development as an alternative to rhBMP2 to promote spinal fusion.

Effect of cervical kyphotic deformity type on the motion characteristics and dynamic spinal cord compression.

STUDY DESIGN: Retrospective analysis of kinematic magnetic resonance images. OBJECTIVE: To provide baseline data on the segmental angular and translational motion of the degenerated cervical spine by subtype of kyphotic cervical deformity and to elucidate the relationship between motion and degree of spinal cord compression. SUMMARY OF BACKGROUND DATA: Kyphotic deformities of the cervical spine are relatively common and are classified as either global or focal. Nevertheless, the effects of kyphotic subtype on cervical segmental motion and degree of spinal cord compression are unknown. METHODS: A total of 1171 symptomatic patients (618 females, 553 males) underwent cervical kinematic magnetic resonance imaging in the neutral, flexion, and extension positions. Cervical spines demonstrating kyphosis were included and classified into 3 groups: (1) "global kyphotic deformity" (C-type) (n = 54); (2) "sigmoid deformity" (S-type) with kyphotic upper and lordotic lower cervical segments (n = 29); and (3) "reverse sigmoid deformity" (R-type) with lordotic upper and kyphotic lower cervical segments (n = 39). Translational motion, angular motion, and degree of spinal cord compression were evaluated for each cervical level along with the changes associated with flexion and extension. RESULTS: In the C- and R-types, angular motion with extension was increased in the upper cervical spine, where there was kyphosis; when compared with the S-type, in which there was lordosis in the upper segments. The results were opposite for flexion angular motion. R-type displayed more translational motion at C3-C4 and C5-C6. Degree of static spinal cord compression of R-type was higher than the others at C3-C4. The dynamic spinal cord compression increased in extension more than flexion in all subtypes. CONCLUSION: Cervical spine studies that aim to investigate kyphotic deformities should make efforts to discern the different subtypes of kyphotic deformities to more accurately characterize and study the effects that the sagittal alignment has on the kinematics of the spine and the degree of spinal cord compression.

Comparative study of scientific publications in orthopedics journals originating from USA, Japan and China (2000-2012).

PURPOSE: To compare orthopedics publications from USA, Japan and China. METHODS: Scientific papers belong to ''Orthopedics'' category of Science Citation Index Expanded subject categories were retrieved from the "PubMed'' and ''Web of Knowledge'' online databases. RESULTS: In the field of orthopedics, the annual number increased significantly from 2000 to 2012 in the three countries (p<0.001). The share of articles increased significantly in China, but decreased significantly in Japan and USA (p<0.05). In 2012, USA contributed 35.3% of the total world output in orthopedics field and ranked 1st; Japan contributed 5.9% and ranked 4th; China contributed 5.2% and ranked 5th. Publications from USA had the highest accumulated IFs and the highest total citations of articles (USA > Japan > China, p<0.001). Average IF from USA was much higher than Japan and China (p<0.001). USA published the most articles in the top ten orthopedics journals (USA (14355) > Japan (1702) > China (487), p<0.01). CONCLUSION: Although China has undergone significant increase in annual number and percentage of scientific publication in orthopedics journals, it still lags far behind USA and Japan in the field of orthopedics in terms of quantity and quality.

Comparative study of scientific publications in orthopedics journals originating from USA, Japan and China (2000-2012)

PURPOSE: To compare orthopedics publications from USA, Japan and China. METHODS: Scientific papers belong to ''Orthopedics'' category of Science Citation Index Expanded subject categories were retrieved from the "PubMed'' and ''Web of Knowledge'' online databases. RESULTS: In the field of orthopedics, the annual number increased significantly from 2000 to 2012 in the three countries (p<0.001). The share of articles increased significantly in China, but decreased significantly in Japan and USA (p<0.05). In 2012, USA contributed 35.3% of the total world output in orthopedics field and ranked 1st; Japan contributed 5.9% and ranked 4th; China contributed 5.2% and ranked 5th. Publications from USA had the highest accumulated IFs and the highest total citations of articles (USA > Japan > China, p<0.001). Average IF from USA was much higher than Japan and China (p<0.001). USA published the most articles in the top ten orthopedics journals (USA (14355) > Japan (1702) > China (487), p<0.01). CONCLUSION: Although China has undergone significant increase in annual number and percentage of scientific publication in orthopedics journals, it still lags far behind USA and Japan in the field of orthopedics in terms of quantity and quality.