Angeliki Perdios

Assessing Bone Microstructure at the Distal Radius in Children and Adolescents Using HR-pQCT: A Methodological Pilot Study

We examined the use of high-resolution peripheral quantitative computed tomography (HR-pQCT [XtremeCT; Scanco Medical, Switzerland]) to assess bone microstructure at the distal radius in growing children and adolescents. We examined forearm radiographs from 37 children (age 8-14 yr) to locate the position of the ulnar and radial growth plates. We used HR-pQCT to assess bone microstructure in a region of interest (ROI) at the distal radius that excluded the growth plate (as determined from the radiographs) in all children (n=328; 9-21 yr old). From radiographs, we determined that a ROI in the distal radius at 7% of bone length excluded the radial growth plate in 100% of participants. We present bone microstructure data at the distal radius in children and adolescents. From the HR-pQCT scans, we observed active growth plates in 80 males (aged 9.5-20.7 yr) and 92 females (aged 9.5-20.2 yr). The ulnar plate was visible in 9 male and 17 female participants (aged 11.2 ± 1.9yr). The HR-pQCT scan required 3 min with a relatively low radiation dose (<3 μSv). Images from the radial ROI were free of artifacts and outlined cortical and trabecular bone microstructure. There is currently no standard method for these measures; therefore, these findings provide insight for investigators using HR-pQCT for studies of growing children.

Evidence-based medicine analysis of all pedicle screw constructs in adolescent idiopathic scoliosis.

Study Design. Focus paper. Objective. To evaluate the current evidence-based medicine (EBM) literature in the use of pedicle screw constructs in patients with adolescent idiopathic scoliosis. Summary of Background. EBM has evolved over the past 20 years to provide a framework for the evaluation of therapy and the application of that assessment to a particular patient or a disease. Application of EBM analysis to spinal instrumentation, and specifically to pedicle screw constructs, is challenging. Methods. Cochrane database, Ovid Medline, and PubMed were searched using the terms “pedicle screws” and “adolescent idiopathic scoliosis.” The reference list of the major papers by authors Lenke, Suk, and Kim were hand searched. Relevant articles were retained if they described a pedicle screw construct to correct AIS or compared pedicle screw constructs with another technique. Articles that did not have patients with adolescent idiopathic scoliosis in their subject groups or did not use pedicle screws as a part of their deformity correction were excluded from the study. Results. Based on the search strategy described above, 40 articles met the inclusion criteria and were selected for review in this manuscript. Of these, 32 studies are retrospective reviews including 2 studies that do not define their data collection technique. Six studies have a prospective study design, 1 is a case report, and 1 is a cadaveric study. Conclusion. In the absence of evidence from randomized trials, surgeons must rely on the best available information to guide patient management decisions. Although there have been many publications on the topic of all pedicle screw constructs in AIS, evidence regarding the advantage of all pedicle screw constructs remain limited to case series, biomechanical studies, and expert opinions.

Minimizing Tourniquet Pressure in Pediatric Anterior Cruciate Ligament Reconstructive Surgery : A Blinded, Prospective Randomized Controlled Trial

Background: Tourniquet cuff pressures in pediatric patients are commonly set at standard pressures. Recent evidence on adult subjects has shown that safer and more effective cuff pressures can be achieved by measuring limb occlusion pressure (LOP) and using a wide contour cuff. There is little evidence validating these techniques in children. The primary objective of this study was to evaluate if a difference in tourniquet cuff pressure can be achieved in a pediatric population using a wide contour cuff in conjunction with measured LOP when compared with a standard cuff and pressure. Methods: Subjects aged 10 to 17 years that underwent anterior cruciate ligament repair were included and randomized into either the control group or the experimental LOP group using variable block randomization. The tourniquet cuff was inflated to 300 mm Hg in the control group or to the recommended tourniquet pressure based on LOP measurement in the LOP group. The surgeon was blinded to cuff selection, application, and pressure throughout the surgical procedure. Immediately after the surgical procedure, the surgeon rated the quality of the bloodless field on a visual analog scale. This study was powered as an effectiveness trial, and intention to treat analysis was used. Results: After a planned interim analysis at midpoint, complete data were recorded for 11 (control group) and 10 (LOP group) patients. The quality of the surgical field was not different between the groups (P = 0.053). There was a statistically significant difference in the mean cuff pressure between the control (300 mm Hg) and the LOP (151 mm Hg) groups (P < 0.001). We ran the same analysis comparing the LOP data with the hypothetical control data of 250 mm Hg, and our results remained statistically significant (P < 0.001). Conclusions: The use of an automatic LOP measurement with the use of wide contour cuffs can significantly reduce mean tourniquet cuff pressures in pediatric patients compared with the typical practice of 300 or 250 mm Hg without compromising the quality of the surgical field. Level of Evidence: Level 1, prospective randomized controlled trial.

Pediatric lumbar Chance fractures in British Columbia: chart review and analysis of the use of shoulder restraints in MVAs.

Chance fractures of the skeletally immature spine classically occur in frontal motor vehicle accidents (MVAs) when the occupants are restrained by a lap belt only and undergo traumatic hyperflexion of the torso during the impact. We retrospectively examined all MVA-related Chance fractures at British Columbias Childrens Hospital since 1986, by collecting injury and seat-belt use information from chart data and imaging studies. Twenty-six patients were included in the study, 14 wore a lap belt only, seven wore a three-point restraint properly, and five were reportedly misusing the shoulder portion of a three-point restraint. The subjects ranged in age from 3 to 16 with a mean age of 10.6 years. Eleven of the 26 (42%) patients sustained abdominal viscera injuries, seven of the 26 patients suffered neurologic injury (spinal cord and/or spinal nerve injury) associated with their spinal fracture, with two cases of complete paralysis, and there was a 38% incidence of head injury. Concomitant injuries (i.e. to the head, abdomen and abdominal contents) tended to be mitigated by the presence of a properly worn shoulder restraint. This leads to the conclusion that Chance fractures can be sustained even when the occupant is using a shoulder belt to restrain their torso. The mechanism responsible for this is unknown. This may indicate that Chance fractures can be caused by a lesser degree of torso hyperflexion than previously thought. Alternatively, we also speculate that Chance fractures can occur while the torso is restrained by the shoulder belt if the hips submarine beneath the lap belt and the torso experiences hyperflexion secondary to forward excursion of the pelvis and legs during the collision. Future work is necessary to confirm these mechanisms and to find ways to prevent them. These studies will need to use computational or experimental child surrogates that can sit in a slouched posture and submarine during a collision.

Effects of camber on wheeling efficiency in the experienced and inexperienced wheelchair user

The objective of this study was to determine whether energy costs differed between 0 degrees , 3 degrees , and 6 degrees of camber during steady state overground wheeling. Three subject groups were examined: experienced wheelchair users with disabilities (thoracic lesion level 6 and below), nondisabled individuals with manual wheeling experience, and nondisabled individuals with no manual wheeling experience. Heart rate, rating of perceived exertion, visual analog scale for comfort, and a user preference questionnaire were collected for all subjects. Expired gas analysis data were collected for the group with disabilities. No statistically significant differences emerged in respiratory measures for camber angle or group. A camber of 6 degrees was most preferred in terms of stability on a side slope, hand comfort on the pushrims, maneuverability, and overall preference. Rear-wheel camber angle did not affect the energy expenditure of manual wheelchair propulsion, as measured by cardiopulmonary means. The individual manual wheelchair users perceived level of comfort should be the determining factor in rear-wheel camber selection.

The use of CT in the development and implementation of a preoperative protocol to aid in pedicle screw placement during scoliosis surgery.

Scoliosis surgical constructs, using pedicle screws, provide increased fixed penetrable points for rod attachment. This allows improved curve correction and increases hardware stability. We have implemented a multidetector CT evaluation of the spine with post-process image manipulation to aid pedicle screw placement for deformity correction. Preoperative scanning was done with a Philips Brilliance 16 multislice CT scanner. The created image dataset provided valuable preoperative information regarding pedicle morphology, suitability for screw placement and preoperative screw planning. Projected intraoperatively, the images increased the surgeon’s confidence during screw placement, especially in large deformities with severe rotation. Improving pre- and intraoperative pedicle information is a valuable tool in operative management of children with spinal deformity.

Outcome Analysis of Chance Fractures of the Skeletally Immature Spine

Study Design. Observational. Objective. The authors present a detailed description of 25 skeletally immature patients with Chance fractures with a mean follow-up of 6.4 years. Summary of Background Data. Since the legislation mandating seat belt usage in Canada was first introduced, the fatality rate of automobile collisions has decreased significantly. However, seat belts do not result in the complete elimination of injury. Fractures of the lumbar spine due to seat belts are well recognized in adolescents and adults but there are few reports in young children. Methods. Radiographic images and patient records were analyzed for information on patient demographics and injury details. Results. Treatment involved either posterior instrumentation (n = 16) or a conservative approach using casting or bracing (n = 9). Concomitant injuries were documented. A deformity index was developed as a simple value to take into account the severity of both anterior loss of vertebral height and posterior distraction. Conclusion. The deformity index was significantly higher in patients with a concomitants abdominal injury and significantly higher in patients managed operatively. Functional outcome scores were completed on 14 of the patients. Patients scored within the reported norms on the SF-36 version 2 but scored poorly on the pain and disability component of the AAOS lumbar specific questionnaire. These outcomes indicate a need for using an injury specific score to accurately quantify disability.

Peroneal Spastic Flatfoot Caused by a Talar Osteochondral Lesion: A Case Report:

This is a case of a 16-year-old boy presenting with a peroneal spastic flatfoot in which an ipsilateral talar osteochondral lesion was detected on MRI. Peroneal spastic flatfoot is a disorder that usually is caused by tarsal coalition. In some patients, despite a classic clinical presentation, a coalition is not identified. MRI may demonstrate a fibrous coalition or, in some cases, inflammatory changes within the subtalar joint.5 Talar osteochondral lesions, frequently referred to as osteochondritis dissecans, have been well described and classified.1–3,7 They appear to have a mixed etiology with some overlap between clearly traumatic osteochondral fractures and atraumatic lesions. Significant trauma is reported in 70% of patients with medial lesions.2 Osteochondral lesions usually are not considered in the differential diagnosis of a peroneal spastic flatfoot. Remarkably, in our patient the peroneal spasm and flatfoot resolved with the successful treatment of the osteochondral lesion.