Chronic hypoxia has a differential effect on left and right ventricular ACE activity and that the sites of altered ACE expression are highly localized. We speculate that locally increased right ventricular ACE activity and expression may play a role in the pathogenesis of right ventricular hypertrophy secondary to hypoxic pulmonary hypertension.

Object Upper cervical spine injuries in the pediatric age group have been recognized as extremely unstable from ligamentous disruption and as potentially lethal. Few measurement norms have been published for the pediatric upper cervical spine to help diagnose this pathological state. Instead, adult measurement techniques and results are usually applied inappropriately to children. The authors propose using high-resolution reconstructed CT scans to define a range of normal for a collection of selected upper cervical spine measurements in the pediatric age group. Methods Sagittal and coronal reformatted images were obtained from thin axial CT scans obtained in 42 children (< 18 years) in a 2-month period. There were 25 boys and 17 girls. The mean age was 100.9 months (range 1–214 months). Six CT scans were obtained for nontrauma indications, and 36 were obtained as part of a trauma protocol and later cleared for cervical spine injury. Six straightforward and direct linear distances—basion-dental interval (BDI); atlantodental interval (ADI); posterior atlantodental interval (PADI); right and left lateral mass interval (LMI); right and left craniocervical interval (CCI); and prevertebral soft-tissue thickness at C-2—that minimized logistical and technical distortions were measured and recorded. Statistical analysis including interobserver agreement, age stratification, and sex differences was performed for each of the 6 measurements. Results The mean ADI was 2.25 ± 0.24 mm (± SD), the mean PADI was 18.3 ± 0.07 mm, the mean BDI was 7.28 ± 0.10 mm, and the mean prevertebral soft tissue width at C-2 was 4.45 ± 0.43 mm. The overall mean CCI was 2.38 ± 0.44 mm, and the overall mean LMI was 2.91 ± 0.49 mm. Linear regression analysis demonstrated statistically significant age effects for PADI (increased 0.02 mm/month), BDI (decreased 0.02 mm/month), and CCI (decreased 0.01 mm/month). Similarly significant effects were found for sex; females demonstrated on average a smaller CCI by 0.26 mm and a smaller PADI by 2.12 mm. Moderate to high interrater reliability was demonstrated across all parameters. Conclusions Age-dependent and age-independent normal CT measurements of the upper cervical spine will help to differentiate physiological and pathological states in children. The BDI appears to change significantly with age but not sex; on the other hand, the LMI and ADI appear to be age-independent measures. This preliminary study suggests acceptable levels of interrater reliability, and further expanded study will aim to validate these measurements to produce a profile of normal upper cervical spine measurements in children.

Object Neurophysiological monitoring of motor evoked potentials (MEPs) during complex spine procedures may reduce the risk of injury by providing feedback to the operating surgeon. While this tool is a well-established surgical adjunct in adults, clinical data in children are sparse. The purpose of this study was to determine the reliability and safety of MEP monitoring in a group of children younger than 3 years of age undergoing neurosurgical spine procedures. Methods A total of 10 consecutive spinal procedures in 10 children younger than 3 years of age (range 5–31 months, mean 16.8 months) were analyzed between January 1, 2008, and May 1, 2010. Motor evoked potentials were elicited by transcranial electric stimulation. A standardized anesthesia protocol for monitoring consisted of a titrated propofol drip combined with bolus dosing of fentanyl or sufentanil. Results Motor evoked potentials were documented at the beginning and end of the procedure in all 10 patients. A mean baseline stimulation threshold of 533 ± 124 V (range 321–746 V) was used. Six patients maintained MEP signals ≥ 50% of baseline amplitude throughout the surgery. There was a greater than 50% decrease in intraoperative MEP amplitude in at least 1 extremity in 4 patients. Two of these patients returned to baseline status by the end of the case. Two patients had a persistent decrement or variability in MEP signals at the end of the procedure; this correlated with postoperative weakness. There were no complications related to the technique of monitoring MEPs. Conclusions A transcranial electric stimulation protocol monitoring corticospinal motor pathways during neurosurgical procedures in children younger than 3 years of age was reliably and safely implemented. A persistent intraoperative decrease of greater than 50% in this small series of 10 pediatric patients younger than 3 years of age predicted a postoperative neurological deficit. The authors advocate routine monitoring of MEPs in this pediatric age group undergoing neurosurgical spine procedures.

VATS technique should be considered for a safe, efficacious, and durable CSF leak repair and as an alternative to open thoracotomy in the pediatric age group.