Luo, T. David

Background: Intraoperative computed tomography and image-guided navigation improve the accuracy of screw placement. Radiation exposure to the patient remains a primary drawback. The objective of the present study was to compare the total intraoperative radiation dose and assess the resultant image quality for O-arm-assisted pedicle screw insertion, among 3 protocols: default (manufacturer recommended), institutional (reduced dose utilized in our institution), and pediatric (new protocol with lowest dose). Methods: Thirty-seven consecutive patients under the age of 18 years underwent posterior instrumentation of the spine and underwent an intraoperative O-arm scan. Techniques (kV and mAs) for default and institutional dose settings were manually adjusted based on spinal level and body weight. Pediatric dose techniques were 80 kV/80 mAs with no adjustment for level or weight. The number of scans repeated because of inadequate imaging was assessed, and the mean estimated effective dose between the 3 protocols was compared. Results: Sixty-eight scans were performed in 37 consecutive patients with mean age of 14 years and mean weight of 55 kg. For reference, the effective radiation dose of a chest x-ray is approximately 0.10 mSv. Use of the default protocol resulted in higher mean effective dose per scan of 4.65 mSv, whereas institutional protocol resulted in 2.37 mSv. The pediatric protocol reduced the mean dose to 0.65 mSv. The total effective dose per surgery was: 1.17 mSv (pediatric), 3.83 mSv (institutional), and 12.79 mSv (default) (P<0.0001 each). All scans lead to satisfactory image quality except in 1 patient >100 kg with stainless steel implants. There were no neurological or other implant-related complications. The pediatric protocol resulted in satisfactory image quality with the lowest total radiation dose, only 1/10 of that of the default protocol. Conclusions: We successfully switched to a pediatric low-dose O-arm protocol in clinical practice, reducing the dose to <1/4 of the mean annual natural background radiation. This may allow use of intraoperative computed tomography and navigation for pedicle screw placement without excessive radiation exposure to young patients. Level of Evidence: Level III—retrospective comparative study.

OBJECT Motocross racing is a popular sport; however, its impact on the growing/developing pediatric spine is unknown. Using a retrospective cohort model, the authors compared the degree of advanced degenerative findings in young motocross racers with findings in age-matched controls. METHODS Patients who had been treated for motocross-related injury at the authors' institution between 2000 and 2007 and had been under 18 years of age at the time of injury and had undergone plain radiographic or CT examination of any spinal region were eligible for inclusion. Imaging was reviewed in a blinded fashion by 3 physicians for degenerative findings, including endplate abnormalities, loss of vertebral body height, wedging, and malalignment. Acute pathological segments were excluded. Spine radiographs from age-matched controls were similarly reviewed and the findings were compared. RESULTS The motocross cohort consisted of 29 riders (mean age 14.7 years; 82% male); the control cohort consisted of 45 adolescents (mean age 14.3 years; 71% male). In the cervical spine, the motocross cohort had 55 abnormalities in 203 segments (average 1.90 abnormalities/patient) compared with 20 abnormalities in 213 segments in the controls (average 0.65/patient) (p = 0.006, Student t-test). In the thoracic spine, the motocross riders had 51 abnormalities in 292 segments (average 2.04 abnormalities/patient) compared with 25 abnormalities in 299 segments in the controls (average 1.00/patient) (p = 0.045). In the lumbar spine, the motocross cohort had 11 abnormalities in 123 segments (average 0.44 abnormalities/patient) compared with 15 abnormalities in 150 segments in the controls (average 0.50/patient) (p = 0.197). CONCLUSIONS Increased degenerative changes in the cervical and thoracic spine were identified in adolescent motocross racers compared with age-matched controls. The long-term consequences of these changes are unknown; however, athletes and parents should be counseled accordingly about participation in motocross activities.

OBJECT Off-road motorcycling is a very popular sport practiced by countless people worldwide. Despite its popularity, not much has been published on the severity and distribution of central nervous system–related injuries associated with this activity in the pediatric population. The purpose of this study was to confirm, characterize, and document the rate of head and spine injuries associated with off-road motorcycling in this population. METHODS All patients aged 18 years or less who were treated for a motorbike injury at the authors' institution (a Level 1 regional trauma center) between 2000 and 2007 were identified through in-house surgical and trauma registries. Type, mechanism, and severity of CNS-related injuries were assessed, including: incidence of traumatic brain injury (TBI), loss of consciousness (LOC), Glasgow Coma Scale (GCS) score, head CT findings, neurological deficits, spinal fractures, cervical strain, and use of protective gear, including helmets. RESULTS During the 8-year period of study, 298 accidents were evaluated in 248 patients. The patients' mean age at the time of injury was 14.2 ± 2.7 years. Head injury or TBI was identified in 60 (20.1%) of 298 cases (involving 58 of 248 patients). Fifty-seven cases were associated with LOC, and abnormalities were identified on head CT in 10 patients; these abnormalities included skull fractures and epidural, subdural, subarachnoid, and intraparenchymal hemorrhages. The GCS score was abnormal in 11 cases and ranged from 3 to 15, with an overall mean of 14.5. No patients required cranial surgery. Helmet use was confirmed in 43 (71.6%) of the cases involving TBI. Spine fractures were identified in 13 patients (4.3%) and 5 required surgical fixation for their injury. CONCLUSIONS The authors found a high occurrence of head injuries following pediatric off-road motorcycle riding or motocross accidents despite the use of helmets. Additionally, this study severely underestimates the rate of mild TBIs in this patient population. Our data indicate that motocross is a high-risk sport despite the use of protective gear. Riders and parents should be counseled accordingly about the risks prior to participation.

OBJECT Action motorsports, including motocross, have been gaining popularity among children and adolescents, raising concerns for increased risk of concussions in participating youth. The authors undertook this study to test the following hypotheses: 1) that there is a high rate of concussion symptoms associated with a number of preventable or adjustable risk factors, and 2) that a high percentage of these symptoms are not be reported to adults and medical personnel. METHODS The authors identified all motocross riders under the age of 18 at a regional racetrack during the riding season between May and October 2010. The participants completed questionnaires pertaining to demographic characteristics and variables associated with motocross. The questionnaire results were compared with the incidence of self-reported concussion symptoms. RESULTS Two hundred two riders were identified who met the criteria for participation in the study, and 139 of them completed the study questionnaire. Of these 139 riders, 67 (48%) reported at least 1 concussion symptom during the season. The majority of riders (98%) reported “always” wearing a helmet, and 72% received professional help with fitting of their helmets. Proper helmet fitting was associated with a 41% decreased risk of concussion symptoms (RR 0.59, 95% CI 0.44–0.81, p < 0.01). Sixty-six riders (47%) reported having received sponsor support for motocross participation. Sponsor support conferred a relative risk for concussion symptoms of 1.48 (95% CI 1.05–2.08, p = 0.02). CONCLUSIONS Nearly half of all motocross competitors under the age of 18 reported concussion symptoms. Preventive measures are necessary to limit the negative impact from concussions. The risk of concussive injury can be decreased for pediatric motocross riders if they receive professional help with proper helmet fitting and through implementation of stricter guidelines regarding sponsorship.

Background: Femoral nerve block (FNB) has become a popular method of postoperative analgesia for anterior cruciate ligament (ACL) reconstruction in pediatric and adolescent patients. Successful rehabilitation after surgery involves return of quadriceps and hamstring strength. Purpose: To compare knee strength and function 6 months after ACL reconstruction in pediatric and adolescent patients who received FNB versus patients with no nerve block. Study Design: Cohort study; Level of evidence, 3. Methods: Patients 18 years or younger who underwent primary ACL reconstruction between 2000 and 2010 at a single institution were identified. If the patient was skeletally immature, a transphyseal ACL reconstruction was performed. Of these patients, 68% underwent reconstruction with a patellar tendon autograft, and in 32% of patients a hamstring autograft was utilized. There were 124 patients who met the study inclusion criteria, including 62 in the FNB group (31 males, 31 females) and 62 patients in the control group (25 males, 37 females). All study patients participated in a comprehensive rehabilitation program that included isokinetic strength and functional testing at 6 months postoperatively. Results: Univariate analysis showed a significantly higher deficit at 6 months in the FNB group with respect to fast isokinetic extension strength (17.6% vs 11.2%; P = .01) as well as fast (9.9% vs 5.7%; P = .04) and slow (13.0% vs 8.5%; P = .03) isokinetic flexion strength. There was no difference in slow isokinetic extension strength deficit between the 2 groups (FNB, 22.3% vs control, 18.7%; P = .20). With respect to function, there were no differences in deficit for vertical jump (FNB, 9.4% vs control, 11.3%; P = .30), single hop (7.6% vs 7.5%; P = .96), or triple hop (8.0% vs 6.6%; P = .34) between the 2 groups. A significantly higher percentage of patients in the control group met functional and isokinetic criteria for return to sports at 6 months (90.2% vs 67.7%; odds ratio, 4.37; P = .002). Conclusion: Pediatric and adolescent patients treated with FNB for postoperative analgesia after ACL reconstruction had significant isokinetic deficits in knee extension and flexion strength at 6 months when compared with patients who did not receive a nerve block. Patients without a block were 4 times more likely to meet criteria for clearance to return to sports at 6 months.

Objectives: Femoral nerve blockade has become a popular method of postoperative analgesia for anterior cruciate ligament (ACL) reconstruction in pediatric and adolescent patients. Successful rehabilitation after ACL reconstruction involves return of quadriceps and hamstring strength and dynamic knee stability. The objective of this study was to compare strength and function six months after ACL reconstruction in pediatric and adolescent patients who received a femoral nerve block versus a control group of patients with no nerve block. Methods: A search of our institutional database was performed to identify patients 17 years of age or younger who underwent primary ACL reconstruction between 2001 and 2010. Revision ACL surgeries and previous contralateral and ipsilateral knee surgeries were excluded. Based on institutional protocol, the patients participated in a comprehensive rehabilitation program and underwent isokinetic strength testing (slow and fast activation) and functional testing (vertical jump, single hop, triple hop) at six months after ACL reconstruction. Results: There were 127 patients that met the inclusion criteria, including 63 patients in the NB group (32 males, 31 females) and 64 patients in the control group (26 males, 38 females). There were no significant differences between the NB group and the control group with respect to age (15.7 ± 1.4 vs. 15.5 ± 1.4, p = 0.26), sex (p = 0.29), BMI (23.7 ± 3.6 vs. 23.8 ± 3.6, p = 0.91), or type of graft used (67% patellar tendon autograft, 33% hamstring autograft vs. 70% patellar tendon autograft, 30% hamstring autograft, p = 0.85). Univariate analysis showed a significantly higher deficit at six months in the NB group with respect to fast isokinetic extension strength (17.6% vs. 11.3%, p = 0.008), as well as fast (12.8% vs. 8.3%, p = 0.029) and slow (9.9% vs. 5.5%, p = 0.029) isokinetic flexion strength. There was no difference in slow extension isokinetic strength deficit between the two groups (NB 22.1% vs. control 18.9%, p = 0.246).. With respect to function, there were no differences in deficit for vertical jump (NB 9.3% vs. control 11.3%, p = 0.267), single hop (NB 7.5% vs. control 7.6%, p = 0.970), or triple hop (NB 7.9% vs. control 6.5%, p = 0.375) between the two groups. A higher percentage of patients in the control group met criteria for return to sports at six months. (88.9% vs. 68.3%, p = 0.008). Conclusion: Pediatric and adolescent patients treated with a femoral nerve block for postoperative pain control after ACL reconstruction had significant isokinetic deficits in knee extension (quadriceps) and flexion (hamstring) strength at six months when compared to patients who did not receive a nerve block. No differences in the results of functional testing were observed between the two groups. A significantly higher percentage of patients in the group who did not receive a block were cleared to return to sports at six months following ACL reconstruction.

Purpose The purposes of this study were to determine the frequency of acute and subacute complications (within 6 months) of arthroscopic knee procedures in patients aged 17 years or younger and to determine associated risk factors. Methods We identified all patients aged 17 years or younger who underwent arthroscopic knee procedures at our institution from 1997 to 2009. Patient demographic and surgical data were collected from the medical and surgical records, with specific focus on intraoperative and postoperative complications. Results During the study period, 1,002 knee arthroscopies were reviewed. The overall complication rate was 14.7%. Major complications occurred in 21 surgeries (2.1%) and included the following: septic arthritis (n = 3, 0.3%), wound complication requiring operative revision (n = 9, 0.9%), arthrofibrosis requiring manipulation (n = 4, 0.4%), other unplanned subsequent surgery (n = 4, 0.4%), and death (n = 1, 0.1%). Surgeries with an anesthesia time of 265 minutes or greater ( P = .026), operative time of 220 minutes or greater ( P = .013), or tourniquet time of 114 minutes or greater ( P < .001) and surgeries with 3 or more Current Procedural Terminology codes ( P = .003) had a statistically significant increase in risk of major complications. The incidence of minor complications was 12.6%, which included persistent effusion/hemarthrosis requiring arthrocentesis (n = 59, 5.9%) and superficial wound infection (n = 18, 1.8%). Conclusions Major complications after knee arthroscopy in children and adolescents are rare, but minor complications are more common. If possible, surgeons should avoid prolonged anesthesia, surgery, and tourniquet times. The pediatric patient's medical and family history should be reviewed to identify important risk factors. Level of Evidence Level IV, therapeutic case series.