Biomedical subjects

R L Ferguson

Publications and source records attributed to R L Ferguson.

43 records · Page 3Linked to original sources

PubMedDate not supplied

The Galveston technique of pelvic fixation with L-rod instrumentation of the spine.

From April 1978 to October 1982, the authors performed 44 pelvic fixations as part of L-rod instrumentation of a spinal deformity. Thirty scoliosis and revision scoliosis cases with a minimum of 1 year follow-up were analyzed for changes of the instrumentation with respect to the pelvis, angular changes at the lumbosacral junction, radiolucency about the portions of the rods providing pelvic fixation, and success of lumbosacral fusion. The technique for fixation was different among three groups of patients. A pelvic fixation technique in which the pelvic segments of the rods were longer than 6 cm, completely intraosseous through their iliac course, and within 1.5 cm of the sciatic notch, yielded the best results.

Adolescent↗

PubMedDate not supplied

A biomechanical study of thoracolumbar spinal fractures with bone in the canal. Part I. The effect of laminectomy.

A simulation of thoracolumbar spinal fractures with bone in the canal was performed using fresh cadaver spines. In the study, a hole was drilled anterior to posterior in vertebral body T12 to accommodate a microload cell and displacement transducer that was then manually pushed into the canal to simulate the compressive effect of retropulsed bone on the spinal cord. In this part of the study, measurements were made pre- and postlaminectomy. The results indicated that laminectomy had no decompressive effect with up to 35% occlusion of the canal. Measurements of dural wall deflection during penetration of the load cell indicated that the anterior wall deformed locally due to penetration of the load cell with minimal displacement of the posterior wall occurring.

Adult↗

PubMedDate not supplied

A biomechanical study of thoracolumbar spinal fractures with bone in the canal. Part II. The effect of flexion angulation, distraction, and shortening of the motion segment.

In the second part of this biomechanical study of thoracolumbar spinal fractures with bone in the neural canal contract force on the spinal cord--meningeal complex was measured with relation to varying fracture wedge depth, flexion angulations, and distraction and shortening of the fracture model motion segment. The removal of progressively deeper vertebral body wedges did not change the measured contact force/depth of penetration characteristics, however, the resistance to flexion angulation was decreased. Distraction of the motion segment an average of 5.2 mm increased significantly the contact force at the same depth of penetration compared with the case of normal vertebral body height. Shortening an average of 3.2 mm did not have a significant effect. Flexion angulation to 20 degrees did not change the depth/force characteristic in either the shortened or distracted case.

Adult↗

PubMedDate not supplied

Neurologic injuries with the Galveston technique of L-rod instrumentation for scoliosis.

A group of surgeons who used the Galveston technique for L-rod instrumentation (LRI) were surveyed to learn their experience with associated neurologic injuries. Among 507 LRIs for scoliosis there were two partial cord syndromes (0.4%), 13 "nerve root hyperesthesias" (2.6%), and two other nerve injuries (0.4%). All patients, except one with mild residuals after a partial cord injury, fully recovered from their neurologic problem. Experience in spinal surgery, education about LRI strategies and techniques, hands-on technical instruction, and use of an established process for LRI are believed to be the factors that enabled these surgeons to perform this complex procedure with relative safety.

Adolescent↗

PubMedDate not supplied

Correlation of static to dynamic measures of lower extremity range of motion in cerebral palsy and control populations.

The question addressed in this study was whether static measurements of hip, knee, and ankle range of motion correlate to dynamic measurements of hip and knee function during gait. Range-of-motion measures of the lower extremities taken during physical examination (static variables) were recorded on 80 adolescents with cerebral palsy and 30 adolescent normal controls. Kinematic measurements collected during gait analysis (dynamic variables) were recorded on the same patients and controls. Results indicated no correlation greater than r = 0.50 (R2 < 0.25) between any static and dynamic variable for either group--cerebral palsy patients or controls. The lack of good correlation of these measures indicates static physical examination variables such as popliteal angle and straight-leg raise are not good predictors of dynamic gait, such as knee-extension and hip-flexion variables measured during ambulation in controls or cerebral palsy populations.

Adolescent↗

PubMedDate not supplied

Surgical management of ankle valgus in children: use of a transphyseal medial malleolar screw.

Valgus deformity of the ankle in children is associated with a wide variety of clinical conditions. A retrospective review was performed of 17 children (29 involved extremities) with ankle valgus deformity who had been managed by use of a percutaneously placed, transphyseal medial malleolar screw. Median age at the time of surgery was 11 years, 2 months. Median postoperative follow-up was 2 years, 2 months. Tibiotalar axis and ankle mechanical axis were the best radiographic indicators of ankle valgus deformity. Fibular station and epiphyseal wedging were poor predictors of ankle alignment. Significant improvement in the tibiotalar axis (median, 12 degrees) was noted at follow-up, and the median rate of correction was 0.59 degree/month. Resumption of physeal growth and recurrence of deformity (rate of 0.60 degree/month) was seen when the screws were removed before skeletal maturity. The transphyseal medial malleolar screw is a minimally invasive, minimally morbid, technically simple method of reversible partial epiphysiodesis at the ankle and is an effective technique for the correction of ankle valgus deformity associated with a wide variety of clinical conditions in children.

Adolescent↗

PubMedDate not supplied

Local bone-graft technique for subtalar extraarticular arthrodesis in cerebral palsy.

A modification of the subtalar extraarticular arthrodesis is described in which local bone graft from the calcaneus and talus is used with internal fixation to obtain fusion. Twenty-eight patients with cerebral palsy underwent 52 local bone-graft subtalar arthrodeses to correct valgus deformity of the hindfoot at an average age of 7 years 5 months. The preoperative lateral talocalcaneal angle averaged 44.5 degrees, with the intraoperative and postoperative angles being 35 and 33.5 degrees, respectively. These postoperative figures were significantly different from the preoperative films and remained stable over the average 41-month follow-up period. Six feet did not have radiographic union, yet only two lost correction requiring repeated surgery. Thus 88% of the feet had radiographic union, and 96% had a stable talocalcaneal angle at follow-up. This procedure is quick without the necessity of a distant bone graft and the inherent morbidity associated with it. It is as successful in stabilizing the subtalar joint as are other techniques reported in the literature.

Ankle Joint↗