Stephen K. Mendenhall, Andrew Huh, Janit Pandya, Vincent Alentado, Karl Balsara, Chang Ho, and Andrew Jea
The revelation of normative radiographic measurements for the developing pediatric spine is incomplete. The purpose of this analysis was to determine the normal range of asymmetry of the lateral atlantodental interval (LADI) and define age- and sex-related differences.
A total of 3072 children aged 0–18 years who underwent CT scanning of the cervical spine were identified at Riley Hospital for Children between 2005 and 2017. Patients were stratified by sex and age (in years) into 36 cohorts. Following this stratification, patients within each group were randomly selected for inclusion until 15 patients in each group had been measured (quota sampling). A total of 540 patients were included for study. Right and left linear measurements were performed in the CT axial plane at the C-1 midlateral mass level.
The overall mean difference between the right and left LADI was 0.09 ± 1.23 mm (range -6.05 to 4.87 mm). The magnitude of this asymmetry remained statistically insignificant across age groups (p = 0.278) and sex (p = 0.889). The intraclass correlation coefficient was 0.805 (95% CI 0.779–0.829).
Asymmetry of the LADI is not unusual in asymptomatic children. There is no appreciable difference in magnitude of this asymmetry across age ranges and sex. Measurement of LADI asymmetry shows “good” reliability and is easy to perform. Pediatric neurosurgeons, emergency department physicians, and radiologists should be aware of normative values of asymmetry when interpreting CT scans of the cervical spine. This may prevent unnecessary further workup with dynamic CT or MRI.
Christopher Wilson, Mariana Hoyos, Andrew Huh, Blake Priddy, Stephen Avila, Stephen Mendenhall, Miracle C. Anokwute, George J. Eckert, and David W. Stockwell
Type II odontoid fractures may be managed operatively or nonoperatively. If managed with bracing, bony union may never occur despite stability. This phenomenon is termed fibrous union. The authors aimed to determine associations with stable fibrous union and compare the morbidity of patients managed operatively and nonoperatively.
The authors performed a retrospective review of their spine trauma database for adults with type II odontoid fractures between 2015 and 2019. Two-sample t-tests and Fisher’s exact tests identified associations with follow-up stability and were used to compare operative and nonoperative outcomes. Sensitivity, specificity, and predictive values were calculated to validate initial stable upright cervical radiographs related to follow-up stability.
Among 88 patients, 10% received upfront surgical fixation, and 90% were managed nonoperatively, of whom 22% had fracture instability on follow-up. Associations with instability after nonoperative management include myelopathy (OR 0.04, 95% CI 0.0–0.92), cerebrovascular disease (OR 0.23, 95% CI 0.06–1.0), and dens displacement ≥ 2 mm (OR 0.29, 95% CI 0.07–1.0). Advanced age was not associated with follow-up instability. Initial stability on upright radiographs was associated with stability on follow-up (OR 4.29, 95% CI 1.0–18) with excellent sensitivity and positive predictive value (sensitivity 89%, specificity 35%, positive predictive value 83%, and negative predictive value 46%). The overall complication rate and respiratory failure requiring ventilation on individual complication analysis were more common in operatively managed patients (33% vs 3%, respectively; p = 0.007), even though they were generally younger and healthier than those managed nonoperatively. Operative or nonoperative management conferred no difference in length of hospital or ICU stay, discharge disposition, or mortality.
The authors delineate the validity of upright cervical radiographs on presentation in association with follow-up stability in type II odontoid fractures. In their experience, factors associated with instability included cervical myelopathy, cerebrovascular disease, and fracture displacement but not increased age. Operatively managed patients had higher complication rates than those managed without surgery. Fibrous union, which can occur with nonoperative management, provided adequate stability.