Analysis of postural stability following posterior spinal fusion in adolescents with idiopathic scoliosis.

This study uses experimental data acquired from adolescents with idiopathic scoliosis to assess their postural control during quiet standing before and after posterior spinal fusion. Statistically significant differences were seen when comparing the pre- and post-surgical measures of balance calculated from data for three different test conditions.

Using a bi-planar postural stability model to assess children with scoliosis.

This study examines the postural stability of children with idiopathic scoliosis, using experimental data and a model of sway that includes mediolateral (ML) and anterioposterial (AP) components. The experimental data includes center of pressure (COP) measurements calculated from data acquired using two Advanced Medical Technology, Inc. (AMTI) force plates. Sway metrics are computed and compared with the model simulation, which successfully reproduced the clinical data from 16 children with scoliosis and 20 typically-developing children. This study is part of the first phase of a multi-year study designed to systematically assess whether fusing the spine to L4 in children with scoliosis has a significant impact on physical function and quality of life.

A dynamic model of the upper extremities for quantitative assessment of Lofstrand crutch-assisted gait.

Appropriate models for quantitative evaluation of upper extremity dynamics in children with myelomeningocele are limited. Therefore, a three-dimensional (3D) biomechanical model of the upper extremities was developed for quantification during Lofstrand crutch-assisted gait in children with myelomeningocele. The model accurately tracks the joint angles of the trunk, shoulders, elbows, wrists, and crutches. Lofstrand crutches are instrumented with six-axis load cells to obtain force and moment components. The model is applied while performing crutch-assisted ambulatory patterns (alternate gait and swing-through gait). Analysis indicates that the model is suitable for quantifying upper extremity motion during crutch-assisted gait. This model has been designed for dynamic assessment of ambulatory patterns (upper and lower extremities) that present with pediatric myelomeningocele. It is hoped that the study findings will prove useful through advances in treatment monitoring, crutch prescription and therapeutic planning.

Hemivertebra in monozygotic twins.

STUDY DESIGN: A case report. OBJECTIVES: To report and discuss a case of thoracic hemivertebra in monozygotic twins. SUMMARY OF BACKGROUND DATA: The etiology of congenital scoliosis remains unclear. Both a genetic basis and environmental influences have been postulated. A few isolated reports of discordant spinal anomalies in twins exist. METHODS: Clinical examination and plain radiograph evaluation were performed on female monozygotic twins with congenital scoliosis secondary to thoracic hemivertebra. RESULTS: Congenital thoracic scoliosis was documented in both of a set of monozygotic twins. CONCLUSIONS: To the authors' knowledge, this is the first report of similar congenital vertebral abnormalities in identical twins in the English literature.

Intraobserver reproducibility and interobserver reliability of cervical spine measurements.

Lateral flexion-extension radiographs of 72 patients with Down syndrome were used to assess the interobserver reliability and intraobserver reproducibility of the atlanto-dens interval, Wiesel-Rothman measurement, occiput atlas angle, and Power's ratio in flexion and extension. The radiographs were reviewed by three blinded observers on three different occasions with at least a 1-month interval between assessments. The intraclass correlation coefficient was used to measure the reproducibility of the measurements from a given observer and the reliability between different observers. With the exception of observer one, the atlanto-dens interval had a statistically significant intraobserver agreement compared with any of the other measurements (p < 0.05). The atlanto-dens interval and the Wiesel-Rothman measurements tended to have better correlation between observers, although there was only fair agreement. The agreement, however, was statistically significant (p < 0.05) compared with Power's ratio. The degree of intraobserver reproducibility and interobserver reliability may make it difficult to base treatment protocols on these measurements.

Compression-plate fixation of femoral shaft fractures in children aged 8 to 12 years.

Twenty-one patients between the ages of 8 and 12 years with 23 femoral-shaft fractures underwent dynamic compression plating (DCP) between August 1993 and February 1996. Eleven patients had isolated femoral-shaft fractures, five had associated long-bone injuries, and five had multiple organ injuries. A 4.5-mm DCP plate was used in each case. Patients were kept non-weight bearing with crutches for an average of 8 weeks. Hardware failure occurred in two patients at 6 weeks. One was treated with revision plating, and the other, with spica casting. Both healed uneventfully. No other complications occurred. All patients were radiographically and clinically healed at last follow-up.

Late complication after single-rod instrumentation.

STUDY DESIGN: A case report of late complication after single-rod instrumentation. OBJECTIVES: To report a case of symptomatic, perispinal, soft-tissue complication after successful fusion of a scoliotic curve using a unilateral, posterior, multiple hook-rod construct. SUMMARY OF BACKGROUND DATA: Delayed perispinal soft-tissue complications recently have been observed with two-rod, multihook system constructs. The etiology is believed to be low, virulence bacteria causing delayed infection, or metal fretting causing chronic inflammation. This phenomenon has not been linked to single-rod constructs. METHODS: The observation of perispinal soft-tissue inflammation was made during exploratory surgery for progressive pain overlying the rod. The diagnosis was supported by laboratory findings. RESULTS: Complete pain relief was obtained after removal of the hardware and empiric treatment with an oral antibiotic. CONCLUSIONS: Delayed chronic inflammation may occur as a late complication of the use of a unilateral, posterior, multiple hook-rod construct in the spine. This problem can be managed successfully with hardware removal, and, because the etiology of this type of inflammation is unclear, infection with a low virulence organism should be considered.

Traction versus supine side bending. Which technique best determines curve flexibility?

STUDY DESIGN: A prospective study performed in two institutions where patients scheduled for surgical management of scoliosis were evaluated with traction and supine side bending radiographs to determine curve flexibility. OBJECTIVE: To determine if there is a difference in the flexibility of curves as determined by side bending or traction films. METHODS: Fifty-eight patients scheduled for surgery underwent preoperative radiographic evaluation using supine side bending and traction radiographs. The surgeons were free to use the information as they saw fit in determining levels of fusion. All curves were measured using the method of Cobb. Curves were analyzed in three groups: > 60 degrees, 50-60 degrees, and < 50 degrees. A comparison then was made between the traction and side bend films to determine which method demonstrated greater flexibility. Measurement error was assumed to be +/- 5 degrees. If the measurements were within 5 degrees, then the two methods were considered to be equivalent. RESULTS: In curves > 60 degrees, greater flexibility was seen on traction films. In curves < 50 degrees, side bending showed greater flexibility. In curves between 50 degrees and 60 degrees, side bending showed greater flexibility in the thoracic spine, whereas in the lumbar spine both films showed equivalent flexibility. CONCLUSIONS: Traction shows greater curve flexibility in curves > 50 degrees, whereas in curves < 50 degrees, side bending shows greater flexibility.

Neurologic complications of pediatric femoral nailing.

Neurologic complications of femoral rodding with interlocking nails were investigated in 35 consecutive pediatric patients, aged 10-17 years, with traumatic femur fractures. We examined various risk factors for neurologic complications, including timing and duration of surgery, preoperative and intraoperative traction type, adequacy of preoperative traction, intraoperative patient position, degree of comminution of the fracture, and use of interlocking screws. There were eight (22.2%) neurologic complications. Of these, only two (5.6%) persisted for longer than a week. The combination of surgical delay > 48 h, preoperative shortening, and the use of boot traction increased the incidence of all palsies to 5.68 times and peroneal palsies to 11.4 times that of patients without this combination of risk factors. Adequate pre- and intraoperative skeletal traction, especially in patients with hours of surgical delay, may decrease the incidence of neurologic complications in pediatric femoral nailings.

Ligamentous instability of the knee in children sustaining fractures of the femur: a prospective study with knee examination under anesthesia.

Fifty-five children with 55 fractures of the femur were prospectively studied for the presence of ligamentous instability of the knee within 3 weeks from the time of injury. Two patients (4%) demonstrated instability on examination under anesthesia. A 9-year, 4-month-old boy sustained a second-degree injury to the lateral collateral ligament that healed after hip spica cast treatment. The other patient, a 12-year, 8-month-old boy, sustained an avulsion fracture of the posterior cruciate ligament from the tibial insertion with > 1 cm posterior displacement of the tibia on the posterior drawer test. After placement of an intramedullary rod, the avulsion fracture was treated with open reduction and internal fixation. Although the incidence of ligamentous instability of the knee in this study is less than that reported for adults with femur fractures, children should nevertheless have a thorough knee examination for ligamentous stability as well as radiographic evaluation of the knee.

Lumbar compression fractures secondary to lap-belt use in children.

The correlation between flexion-distraction injuries and lap-belt use has been well documented. Over a 10-year period, we identified seven children admitted to Children's National Medical Center, Washington, DC, with compression fractures of the lumbar spine secondary to lap-belt use. Four were rear seat passengers, and three were in the front seat. The average age was 7 years. Four of the seven (57%) suffered associated abdominal injuries. One died of an associated head injury. We hypothesize that the mechanism of injury in these cases was similar to that in flexion-distraction injuries. The increased elasticity in the posterior ligamentous complex in children may be responsible for the occurrence of these compression fractures rather than the expected flexion-distraction-type injuries.

Lumbar spine injury in a pediatric population: difficulties with computed tomographic diagnosis.

Thirty-five children with lumbar spine injuries were evaluated with computed tomography and plain radiography following blunt trauma. The majority of these children (31) were injured in motor vehicle crashes; most of them (27 of 35, 77%) were restrained by lap-styled safety belts. The other mechanisms of injury included motor vehicle crashes involving a pedestrian (2), a fall (1), and a crush (1). The types of injuries encountered were subluxation or distraction combined with fracture in 18; fracture only in 13; and distraction only in four. Abnormalities were not detected with thick-section computed tomographic (CT) scans in 20 (57%) of the cases. Children involved in motor vehicle crashes are at high risk for lumbar spine injuries, because the sudden deceleration forces may cause hyperflexion, resulting in vertebral body compression or interspinous ligament disruption. Lumbar spine radiographs are necessary in all cases with suspected lumbar spine injury because the abnormality may be missed by thick-section CT scanning and may not be detected even with complementary thin sections.

Upper extremity restraint during hip spica cast application.

Control of the upper extremities of a sedated or anesthetized patient can be a cumbersome and difficult problem during hip spica cast application. To overcome this, we developed a simple technique to control the upper extremities without placing the neurovascular structures under tension while allowing easy venous access for the anesthesia personnel. Use of a simple armboard made of supplies commonly available in the cast room has made this possible. The construction and clinical use of this armboard is described. It has been used successfully for > 12 months at the authors' institution with no untoward effects.

The surgical management of Scheuermann's disease.

Thirty patients of a group of 39 patients with Scheuermann's kyphosis who underwent posterior spine fusion using large-diameter Harrington compression instrumentation were reviewed with a mean follow-up of 71.8 months. The mean curve before surgery was 71.5, and at follow-up, 37.7. The mean loss of correction at review was 6. This procedure was effective in adults with a fixed deformity as long as no anterior bony bridging existed. The authors believe that posterior Harrington instrumentation and spine fusion offer excellent correction of deformity at long-term follow-up without the added morbidity of a second procedure.

Femur fractures in institutionalized patients after hip spica immobilization.

The charts of 77 severely handicapped institutionalized children and young adults were retrospectively reviewed to assess the incidence of femur fractures. No fractures occurred in ambulatory patients. Four of 37 nonambulatory patients who did not have hip surgery (10.9%) had sustained a fracture at some time during their life. Six of 21 (29%) nonambulatory patients who were operated on for subluxed or dislocated hips sustained a femur fracture within 3 months after discontinuation of their spica casts. This risk factor should be taken into account when one considers operation in severely affected nonambulant spastic quadriplegic patients.

Computed tomographic assessment of shelf acetabuloplasty.

Eleven children with cerebral palsy were studied after shelf acetabular augmentation for progressive hip subluxation. Evaluation was based on computed tomography (CT) scans and radiographic measurements. We noted significant improvement in subluxation as measured by migration percentage, without increased subluxation of the nonoperated hip. Preoperatively, our patients had anterior acetabular deficiencies and increased acetabular anteversion, but no posterior deficiency by CT scanning. The acetabular shelves were positioned relatively more anteriorly than posteriorly. This appears to be appropriate owing to the relative anterior deficiencies of the acetabuli in our patients.

Isolated dislocation of the radial head.

Isolated dislocation of the radial head without fracture of the ulna is an uncommon injury. Though rare in children, it has been reported. A review of the world literature revealed only two reported cases in adolescents. This paper presents three previously unreported cases and reviews the mechanism of injury and problems associated with delayed treatment.