Acute traumatic unilateral cervical C4-C5 facet dislocation in pediatric toddlers.

BACKGROUND: The present study is to highlight the challenges in managing cervical spine injuries in toddlers (less than 4 years of age) without neurological deficit. Cases of unilateral cervical C4-C5 facet dislocation in toddlers are very rare. CASE PRESENTATION: A 3-year-old girl suffered cervical spine injury after a motor vehicle collision with unilateral C4-C5 facet dislocation without neurological deficit. Magnetic resonance imaging (MRI) showed no spinal cord injury, Frankel grade E. Initial management was cervical spine protection. Definite treatment and complication were discussed with the patient's parents before closed reduction maneuver with minerva cast was applied under sedation. The patient showed no complication after closed reduction and the cervical spine had aligned well in radiographs. The minerva cast was removed at 8 weeks, at which point neck muscle stretching rehabilitation program started. At one-year follow up, the child was asymptomatic, had full active cervical motion and good function. In radiographs, the cervical spine had normal alignment and was healed. CONCLUSIONS: Unilateral cervical facet dislocation in toddlers is very rare. Closed reduction maneuver and the minerva cast applied were optional in this case. The parents were highly satisfied with the effective treatment and outcome.

Biomechanical Study of Posterior Pelvic Fixations in Vertically Unstable Sacral Fractures: An Alternative to Triangular Osteosynthesis.

STUDY DESIGN: Biomechanical study. PURPOSE: To investigate the relative stiffness of a new posterior pelvic fixation for unstable vertical fractures of the sacrum. OVERVIEW OF LITERATURE: The reported operative fixation techniques for vertical sacral fractures include iliosacral screw, sacral bar fixations, transiliac plating, and local plate osteosynthesis. Clinical as well as biomechanical studies have demonstrated that these conventional techniques are insufficient to stabilize the vertically unstable sacral fractures. METHODS: To simulate a vertically unstable fractured sacrum, 12 synthetic pelvic models were prepared. In each model, a 5-mm gap was created through the left transforaminal zone (Denis zone II). The pubic symphysis was completely separated and then stabilized using a 3.5-mm reconstruction plate. Four each of the unstable pelvic models were then fixed with two iliosacral screws, a tension band plate, or a transiliac fixation plus one iliosacral screw. The left hemipelvis of these specimens was docked to a rigid base plate and loaded on an S1 endplate by using the Zwick Roell z010 material testing machine. Then, the vertical displacement and coronal tilt of the right hemipelves and the applied force were measured. RESULTS: The transiliac fixation plus one iliosacral screw constructions could withstand a force at 5 mm of vertical displacement greater than the two iliosacral screw constructions (p=0.012) and the tension band plate constructions (p=0.003). The tension band plate constructions could withstand a force at 5° of coronal tilt less than the two iliosacral screw constructions (p=0.027) and the transiliac fixation plus one iliosacral screw constructions (p=0.049). CONCLUSIONS: This study proposes the use of transiliac fixation in addition to an iliosacral screw to stabilize vertically unstable sacral fractures. Our biomechanical data demonstrated the superiority of adding transiliac fixation to withstand vertical displacement forces.

COX-2 expression mediated by calcium-TonEBP signaling axis under hyperosmotic conditions serves osmoprotective function in nucleus pulposus cells.

The nucleus pulposus (NP) of intervertebral discs experiences dynamic changes in tissue osmolarity because of diurnal loading of the spine. TonEBP/NFAT5 is a transcription factor that is critical in osmoregulation as well as survival of NP cells in the hyperosmotic milieu. The goal of this study was to investigate whether cyclooxygenase-2 (COX-2) expression is osmoresponsive and dependent on TonEBP, and whether it serves an osmoprotective role. NP cells up-regulated COX-2 expression in hyperosmotic media. The induction of COX-2 depended on elevation of intracellular calcium levels and p38 MAPK pathway, but independent of calcineurin signaling as well as MEK/ERK and JNK pathways. Under hyperosmotic conditions, both COX-2 mRNA stability and its proximal promoter activity were increased. The proximal COX-2 promoter (-1840/+123 bp) contained predicted binding sites for TonEBP, AP-1, NF-κB, and C/EBP-ß. While COX-2 promoter activity was positively regulated by both AP-1 and NF-κB, AP-1 had no effect and NF-κB negatively regulated COX-2 protein levels under hyperosmotic conditions. On the other hand, TonEBP was necessary for both COX-2 promoter activity and protein up-regulation in response to hyperosmotic stimuli. Ex vivo disc organ culture studies using hypomorphic TonEBP+/- mice confirmed that TonEBP is required for hyperosmotic induction of COX-2. Importantly, the inhibition of COX-2 activity under hyperosmotic conditions resulted in decreased cell viability, suggesting that COX-2 plays a cytoprotective and homeostatic role in NP cells for their adaptation to dynamically loaded hyperosmotic niches.

Reliability and Accuracy of Palpable Anterior Neck Landmarks for the Identification of Cervical Spinal Levels.

STUDY DESIGN: A descriptive experimental study. PURPOSE: The purpose of this study was to describe the reliability and accuracy of palpable anterior neck landmarks (angle of the mandible, hyoid bone, thyroid cartilage, and cricoid cartilage) for the identification of cervical spinal levels in a slight neck-extended position as in anterior approach cervical spinal surgery. OVERVIEW OF LITERATURE: Standard, palpable anatomical landmarks for the identification of cervical spinal levels were described by Hoppenfeld using the midline palpable anterior structures (angle of the mandible [C2 body], hyoid bone [C3 body], thyroid cartilage [C4-C5 disc], cricoid cartilage [C6 body], and carotid tubercle [C6 body]) to determine the approximate level for skin incisions. However, in clinical practice, patients are positioned with a slight neck extension to achieve cervical lordosis. This positioning (neck extension) may result in changes in the locations of anatomical landmarks compared with those reported in previous studies. METHODS: This experimental study was conducted on 96 volunteers. Each volunteer was palpated for locating four anatomical landmarks three times by three different orthopedic surgeons. We collected data from the level of the vertebral body or the vertebral disc matching the surface anatomical landmarks from the vertical reference line. RESULTS: Accuracy of the angle of the mandible located at the C2 vertebral body was 95.5%, the hyoid bone located at the C2/3 intervertebral disc was 51.7%, the thyroid cartilage located at the C4 vertebral body was 42%, and the cricoid cartilage located at the C5/6 intervertebral disc was 43.4%. CONCLUSIONS: With the neck in a slightly extended position to achieve cervical lordosis, the angle of the mandible, the hyoid bone, the thyroid cartilage, and the cricoid cartilage were most often located at the C2 body, the C2/3 disc, the C4 body, and the C5/6 disc, respectively. The angle of the mandible and the hyoid bone are highly reliable surface anatomical landmarks for the identification of cervical spinal levels than the thyroid cartilage and the cricoid cartilage.

The Significance of the Trömner Sign in Cervical Spondylotic Myelopathy Patient.

STUDY DESIGN: This study is a diagnostic analysis. OBJECTIVE: To investigate the diagnostic accuracy of Trömner sign in cervical spondylotic myelopathy (CSM), and how its presence correlates with the severity of myelopathy. SUMMARY OF BACKGROUND DATA: A clinical presentation of myelopathy corresponding with image findings is a current standard to diagnose CSM. Trömner sign is an alternative of well-known Hoffmann sign to detect CSM. Little is known about its diagnostic accuracy and how its presence correlates with the severity of CSM. MATERIALS AND METHODS: Consecutive patients with clinical diagnosis of CSM and other cervical spondylosis-related problems were enrolled in either CSM group, cervical spondylotic radiculopathy group, or axial pain group. Normal volunteers and patients without spine-related issues were used as a control. All participants were examined for the presence of myelopathic signs. Magnetic resonance imaging studies of all participants were reviewed by a radiologist. RESULTS: There were 85 participants included in the study. Diagnostic sensitivity was 76%, 94%, 76%, and 36% for Hoffmann sign, Trömner sign, inverted radial reflex, and Babinski sign, respectively. Trömner sign had relatively high sensitivity (95%) despite of mild degree of myelopathy. Negative predictive value was 60%, 85%, 59%, and 38% for Hoffmann sign, Trömner sign, inverted radial reflex, and Babinski sign, respectively. There were 63%-71% of patients in either axial pain group or cervical spondylotic radiculopathy group had positive Trömner sign. Most of CSM patients with cord signal changed had positive myelopathic sign. Regarding CSM patient without cord signal change, most of tests were negative except Trömner sign. CONCLUSIONS: High sensitivity (94%) and relatively high negative predictive value (85%) for Trömner sign indicate the usefulness of Trömner sign in ruling out CSM. High incidence of positive Trömner sign in presymptomatic cervical cord compression patients suggests Trömner sign could have a useful role in early detection of presymptomatic patients.

Apical wiring technique in surgical treatment of adolescent idiopathic scoliosis: the intermediate outcomes between Lenke types.

STUDY DESIGN: Retrospective cohort study of apical wiring technique for surgical treatment of adolescent idiopathic scoliosis patients. OBJECTIVE: To evaluate the intermediate outcome of adolescent idiopathic scoliosis patients treated with apical wiring technique. SUMMARY OF BACKGROUND DATA: Regarding surgical treatment for adolescent idiopathic scoliosis, there are reports of the superiority of coronal plane correction using all-screw constructs compared with all-hook or hybrid constructs. Major limitations of all-screw constructs are thoracic hypokyphosis and increased proximal junctional kyphosis. There are few reports about apical wiring technique outcomes and no reports of this surgical technique comparing Lenke types. METHODS: Consecutive adolescent idiopathic scoliosis patients treated with apical wiring technique were analyzed. Inclusion criteria were patient 21 years old or younger, who underwent a posterior only surgical correction with a follow-up of at least 2 years. Radiographic data were analyzed according to the criteria given by Lenke and colleagues. The radiographic parameters included global balance, Cobb angle, curve flexibility, apical vertebral translation, tilt angle of lower instrumented vertebra, angle of caudal disk to the lower instrumented vertebra, thoracic kyphosis, lumbar lordosis, and proximal junctional angle preoperatively and postoperatively. RESULTS: There was a significant improvement of Cobb angle in every Lenke type with an average correction of 74.6%. At latest follow-up, the average loss of correction was 3.5% (1.9 degrees). The greatest loss of correction for the minor curve of Lenke 2 was 14.1% (5.8 degrees). There was an improvement of thoracic kyphosis in hypokyphosis group (1.9-21.1 degrees; P<0.001) and hyperkyphosis group (49.8-33.2 degrees; P=0.001). Thoracic normokyphosis alignment was also preserved. No cases of abnormal proximal junctional kyphosis were noted in this cohort. CONCLUSIONS: Apical wiring technique for surgical treatment of adolescent idiopathic scoliosis provides an average correction of 71.1% at 3.4 years of average follow-up with harmonious sagittal plane correction even with preexisting abnormal thoracic kyphosis.