Accuracy of fluoroscopically assisted laser targeting of the cadaveric thoracic and lumbar spine to place transpedicular screws

A simple and inexpensive method was developed to obtain a coaxial view of the pedicles to assist with screw insertion. The authors evaluated the accuracy of this device to place transpedicular vertebral screws in a human adult cadaver model. A dual radiation targeting system, a laser targeting system for fluoroscopically guided procedures, was developed to provide an accurate surface entry point and angle of approach to radiographic landmarks. After fluoroscopic cross-hair target localization of the coaxial view of the pedicle, X-ray radiation is turned off and the laser beam allows the surgeon to guide the screw through the pedicle. Nine cadaver spines were removed and mounted. Three surgeons, inexperienced in the technique of pedicle screw placement, fitted instruments to 184 pedicles between L5 and T5. A total of 83 lumbar and 101 thoracic pedicles underwent screw placement. After specimen dissection, the degree and location of any screw perforation were measured by direct inspection. Three screws perforated a pedicle, for an error rate of 1.6%. Two lumbar screws (2.4% error) and one thoracic screw (1% error) perforated the pedicle. No screw was more than 1 mm outside the pedicle. Five other screws, four in the thoracic spine and one in the lumbar spine (error rate of 2.7%) were directed too far laterally and perforated the lateral vertebral body. This low rate of pedicle wall cortical perforation by inexperienced surgeons compares favorably with much higher pedicle perforation rates by experienced surgeons when no imaging was used. In conclusion, this in vitro model using a dual radiation targeting system assisted with the accurate placement of transpedicular vertebral screws with minimal radiation exposure.

Femur shaft fractures in toddlers and young children: rarely from child abuse

One hundred thirty-nine children younger than 4 years were identified retrospectively from the period of 1993 through 1997 to have an isolated fracture of the shaft of one or both femurs. Abuse was classified as group A (definite, likely, or questionable abuse) or group B (unknown cause, questionable accident, likely accident, or definite accident). The average age of the children was 2.3 +/- 1.1 years. Thirteen children, 9% of the total group, average age of 1.1 +/- 1.0 years, were likely to have been abused (group A). A total of 126 children, 91% of the total, average age 2.3 +/- 1.0 years, sustained their fracture most likely as a result of an accident (group B). Whether a child had not yet achieved walking age (toddler) was the strongest predictor of likely abuse. Ten (42%) of 24 of nonwalking children were in group A, whereas only three (2.6%) of 115 of walking children were in group A (p < 0.001). Child Protective Services may have been unnecessary in 42-63% of cases. Unless other evidence of abuse such as an inconsistent story, bruises, or other fractures are present, abuse is very unlikely to be involved in the walking-age child, analogous to the toddler fracture of the tibia.

Intraarticular knee ganglion: a case report of an unusual cause of limping in a 4-year-old

This report describes a 4-year-old boy who presented to the orthopaedic clinic with a primary complaint of limping and refusal to bear full weight on his right leg. An extensive evaluation revealed an intercruciate ganglion cyst of the knee. Diagnostic arthroscopy of the right knee was performed, and the cyst was aspirated and debrided. Magnetic resonance imaging of the knee 3 months and 1 year postoperatively showed a small remnant of the cyst adjacent to the posterior cruciate ligament. At the most recent clinical examination, 13 months postoperatively, the patient was symptom free. To the best of our knowledge, this is the youngest patient in the literature to be diagnosed with an intraarticular knee ganglion.

Untreated acetabular dysplasia of the hip in the Navajo. A 34 year case series followup

Patients born in the Many Farms District of the Navajo Indian Reservation from 1955 to 1961 were studied. Five hundred forty-eight of the 628 infants born (87%) received clinical examinations and pelvic radiographs at some time during the first 4 years of their lives. Eighteen (3.3%) of the 548 infants examined had acetabular dysplasia. Because of traditional cultural beliefs, none of these children received medical treatment. Followup evaluations and radiographs were obtained in these 18 patients during early adolescence. In 10 of the original 18 patients followup evaluations and radiographs were obtained at an average age of 35 years. None of the dysplastic hips progressed to frank dislocation. The mean center edge angle improved from 7 degrees when the patients were 1 year of age, to 29 degrees when the patients were 12 years of age, to 30 degrees when the patients were 35 years of age. Despite overall improvement of hip measurements with maturity, eight hips in five of the 10 patients who were in their fourth decade of life and who were available for examination, had radiographic evidence of residual abnormalities. The hips in patients with subluxation during infancy were less likely to be normal as adults. The results of this 34-year followup study of untreated developmental hip dysplasia showed marked radiographic improvement in all patients during childhood; however, subtle abnormalities persisted in the radiographs of 40% of the hips.

Outpatient pediatric orthopedics. Common and important conditions

Many common pediatric orthopedic conditions can be managed by the pediatrician who has a knowledge of the natural history of these conditions. An accurate diagnosis is necessary to provide proper treatment, give advice to patients, or make referrals to the proper specialist. The authors' find that in approximately 95% of cases, a specific diagnosis can be made and that 40% of patient referrals for orthopedic problems could have been managed by the primary care physician. This article discusses some of the more common pediatric orthopedic problems often encountered by primary care physicians.

Spinal deformity in myelodysplasia. Correction with posterior pedicle screw instrumentation

STUDY DESIGN

A retrospective review of transpedicular instrumentation used in a series of 24 patients with myelodysplastic spinal deformities and deficient posterior elements.

OBJECTIVE

To describe the usefulness and efficacy of these instruments in the treatment of complicated myelodysplastic spinal deformity.

METHODS

The mean preoperative scoliosis was 75.7 degrees (range, 39-130 degrees) in the 22 patients with scoliotic deformities; 4 patients with thoracic hyperkyphoses averaged 70.5 degrees (range, 46-90 degrees) and 10 patients with lumbar kyphoses averaged 80.5 degrees (range, 42-120 degrees). The instrumentation extended to the sacrum in 4 patients and the pelvis in 9; 10 patients also underwent anterior release and fusion and 7 underwent concomitant spinal cord detethering. At an average follow-up of 4.0 years (2.0-7.7 years; one patient died at 8 months), all patients have fused (with the exception of two lumbosacral pseudarthroses).

RESULTS

At last follow-up, deformity measured 32.1 degrees scoliosis (range, 6-85 degrees), 30.8 degrees thoracic kyphosis (range, 24-35 degrees), and 0.0 degree lumbar kyphosis (range, 35 degrees kyphosis to 29 degrees lordosis). Three patients lost some neurologic function after surgery; two recovered within 6 months and one has incomplete recovery. No ambulatory patient lost the ability to walk. Five patients required additional surgical procedures; in three cases, there was instrumentation breakage associated with pseudarthrosis or unfused spinal segments.

CONCLUSIONS

Pedicle screw instrumentation is uniquely suited to the deficient myelodysplastic spine. Compared with historical control subjects, these devices have proven capable of significant correction of both scoliotic and kyphotic deformities. This instrumentation appears particularly useful in preserving lumbar lordosis in all patients and may preserve more lumbar motion in ambulatory myelodysplasia patients.

Chronic physeal fractures in myelodysplasia: magnetic resonance analysis, histologic description, treatment, and outcome

Thirteen myelodysplastic children with 19 chronic physeal fractures were treated. All were treated with prolonged immobilization (average, 5.8 months; range, 3-18 months) in either braces or casts; four of the fractures required operative fixation to facilitate healing. All were healed at 4.8-years follow-up but, in four of the fractures, the growth plate closed prematurely. Three of the children underwent magnetic resonance imaging (MRI) of the injured physes, and one underwent physeal biopsy as part of her operative epiphysiodesis. Histologic analysis revealed three distinct zones of physeal pathoanatomy: a normal zone of proliferation; a thickened, disorganized zone of hypertrophy; and a vascularized zone of fibrous tissue adjacent to the metaphysis. On MRI, there was thickening of the physis and irregularity of the zone of provisional calcification. The physeal cartilage and the juxtametaphyseal fibrovascular tissue enhanced with gadolinium. These findings corroborate earlier mechanistic proposals for physeal injury in myelodysplasia: chronic stress or trauma to the poorly sensate limb produces micromotion at the zone of hypertrophy, yielding a widened, disorganized physis, and leading to fracture, displacement, and delayed union.

A prospective evaluation of idiopathic left thoracic scoliosis with magnetic resonance imaging

Twenty-nine consecutive patients with idiopathic left thoracic scoliosis were prospectively studied using magnetic resonance imaging (MRI). T1-weighted sagittal and axial images were obtained on all patients from the brainstem to the tip of the conus. Two patients (7%) had a syrinx on MRI. The remaining 27 patients had normal MRIs. The prevalence of brainstem and spinal cord anomalies was much less common than reported in previous retrospective reviews.

Childhood scoliosis: clinical indications for magnetic resonance imaging

We retrospectively reviewed the magnetic resonance imaging studies that had been made for ninety-five patients who had idiopathic scoliosis. We wished to determine if we could identify any criteria that should be met before these studies are performed. The study group included thirty-one male patients and sixty-four female patients. The average age at the time of the imaging study was thirteen years (range, one to twenty-eight years). The average curve was 41 degrees (range, 11 to 95 degrees). Fourteen patients were seen to have an intraspinal abnormality on the imaging study: twelve had a syrinx, one had a syrinx and an astrocytoma of the spinal cord, and one had dural ectasia. Five of the eight patients who were less than eleven years old and who had a left thoracic curve had an intraspinal abnormality on the imaging study, but this combination of factors did not indicate the need for operative intervention. Four of the intraspinal abnormalities in the fourteen patients necessitated neurosurgical intervention; if the criteria for obtaining the imaging study had been restricted to neck pain and headache--particularly with exertion--and neurological findings such as ataxia, weakness, and a cavus foot, these abnormalities would have been diagnosed.

Treatment of severe spondylolisthesis in children by reduction and L4-S4 posterior segmental hyperextension fixation

Twenty children with severe lumbosacral spondylolisthesis underwent reduction, posterolateral fusion, and posterior fixation with an L4 to S2, 3, and 4 sublaminar wired rectangular rod to lessen lumbosacral kyphosis, allow early ambulation, and maintain correction. All patients had a postural deformity, 10 had preoperative neurologic findings, and 8 had severe pain. The average percentage of slip improved from 76% preoperatively to 55% postoperatively, and the slip angle improved from 25 degrees to 5 degrees (p < 0.0001). All patients had solid fusion by 6 months and no progression at 43 month follow-up on the average. We conclude that this technique reliably provides partial reduction, solid fixation, and fusion for patients with severe spondylolisthesis while allowing early ambulation. As with any spondylolisthesis reduction technique, neurologic risk should limit this procedure to well-selected patients.