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Biomedical subjects

R L Ferguson

Publications and source records attributed to R L Ferguson.

At least 19 recordsLinked to original sources
PubMed1992

Treatment of slipped capital femoral epiphysis with a spica cast.

Thirteen patients who had seventeen slipped capital femoral epiphyses were managed with a spica cast between 1984 and 1986. The average time in the plaster cast was three months. Complications were noted in fourteen of the hips. Three pressure sores developed in two patients. Further slipping developed in three hips once the cast had been removed, and chondrolysis developed in one of these hips. Chondrolysis developed in eight additional hips, and the lesion was transient in four of them. Degenerative changes developed in all nine hips with chondrolysis, regardless of whether the chondrolysis was transient or permanent. The degenerative changes were Iowa Grade I in three of these hips, Grade II in two hips, and Grade III in four. Chondrolysis developed in six of the eight black patients and in four of the five black boys. Chondrolysis developed in six of the nine hips that had a Grade-II or III slip. These findings have led us to abandon the use of a spica cast as a mode of treatment for slipped capital femoral epiphysis.

Adolescent↗
PubMed1988

Biomechanical comparisons of spinal fracture models and the stabilizing effects of posterior instrumentations.

In this study, the authors evaluated the stiffness of motion segments in intact spines in two spine fracture models, and with each of five implant systems used for posterior fixation of thoracolumbar spine fractures. The devices represented a cross-section of types, including those employing sublaminar wires with and without laminar hooks, pedicle screws, plates, and rods. Two spine fracture models, one partially and one totally destabilized, were used in the tests of the instrumentation. Stiffness, or the magnitude of load needed to produce a unit displacement of the construct in the direction of the applied load, was measured in flexion, extension, lateral bending, and torsion in combination with a compressive force. Both horizontal plane shear and angular displacements were measured in the two fracture patterns. All evaluations were made by testing the difference in stiffness for statistical significance among groups. The results showed significant differences in stiffness without instrumentation among intact spines, partly destabilized spines (anterior two-thirds of disk and posterior ligaments removed), and totally destabilized spines (only anterior longitudinal ligament intact). The implant/spine constructs were least stiff relative to the intact spine in torsion, followed in increasing order of stiffness with flexion, lateral bending, and extension. In the Roy-Camille plate with six-screw fixation was found to produce the stiffest construct, followed by wired Harrington rods, C-rods and J-rods, and the Vermont internal fixator.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMed1988

The Galveston experience with L-rod instrumentation for adolescent idiopathic scoliosis.

Eighty patients were treated with L-rod instrumentation (LRI) for adolescent idiopathic scoliosis at the authors' institution from 1978 through 1985. The percentage correction of Cobb angle, the fusion rate, and the neurologic injury rate were similar to that reported for Harrington instrumentation. Avoidance of postoperative casting or bracing, maintenance of secondary spinal contours, secure pelvic fixation when needed, and anterior thoracoplasty in a majority of patients were achievable goals with LRI.

Adolescent↗
PubMed1988

A 1988 perspective on the Galveston technique of pelvic fixation.

The Galveston technique for pelvic fixation was used in 40 patients who underwent scoliosis surgery with pelvic fixation at The University of Texas Medical Branch from February 1980 through June 1987. Analysis of the outcomes indicates that extension of a scoliosis fusion to the pelvis can be undertaken with excellent chance for success and without the necessity of routine postsurgical casting or bracing. Accurate contouring of the L-rod implant and meticulous fusion technique are essential to success.

Adolescent↗
PubMed1988

Considerations in the treatment of cerebral palsy patients with spinal deformities.

The natural history of spinal deformities in the cerebral palsy patient is different than that in the idiopathic patient. Consequently, the approach to the patient with cerebral palsy and the surgical decision-making are different from that in the idiopathic patient. The present article gives the UTMB approach to the treatment of the cerebral palsy patient and the unique considerations that must be taken into account when treating these patients. Specific references are made to the use of L-rod instrumentation to stabilize the spinal deformity in the cerebral palsy patient.

Adolescent↗
PubMed1987

Rib regeneration area as an indicator of fusion area in adolescent idiopathic scoliosis.

This retrospective study of 24 patients with adolescent idiopathic scoliosis who underwent L-rod instrumentation, posterior thoracoplasty, and rib-bone grafting analyzed the correlation between the quality of rib regeneration and the host response to the rib-bone grafts. A planimetric technique was used to quantitate the coronal plane area of the resected ribs and of an L1-L2 concave fusion area immediately after surgery and at the end of the first postsurgical year. Using computerized regression analysis, these and other variables such as age, Cobb angle, and grafting technique were studied. Rib regeneration correlated with spinal fusion but not with age or Cobb angle. A better host response with strip vs. morseled graft was suggested, but not statistically proven. The data strongly support the belief that systemic biologic factors are a major variable affecting the quality of the fusion procedure.

Adolescent↗
PubMed1987

The biomechanics of decompressive laminectomy.

The biomechanical effect of laminectomy as a means of relieving compression of the spinal cord-meningeal complex by an anterior mass was studied in ten grossly normal human cadaver spines. The basic experimental set-up involved drilling a sagittal plane hole transversely across a vertebral body to provide direct access to the anterior aspect of the neural canal. After securing a probe and linearly variable differential transformer (LVDT) assembly at each site to be tested, the probe was gently pushed into the neural canal; contact force against the tip of the probe as well as the depth of probe penetration was measured and recorded. Laminectomy did not alter the resulting contact force/anterior penetration plots at the fifth cervical, seventh thoracic, 12th thoracic, or third lumbar vertebra. Using the probe/LVDT assembly to measure anterior dural displacement and a cantilever displacement device to measure posterior dural displacement after laminectomy at the 12th thoracic vertebra, the authors found that although the anterior dura underwent gross displacement as the probe was pushed into the neural canal, the posterior dura displaced to a minimal degree. The extent of the laminectomy was not a factor. The study did not demonstrate any possible mechanism by which laminectomy could reduce the pressure exerted on the dura and neural elements by an anterior mass in a spine with otherwise normal neural canal dimensions.

Biomechanical Phenomena↗
PubMed1986

An algorithm for the treatment of unstable thoracolumbar fractures.

This article describes a fracture classification used at the University of Texas Medical Branch that takes into account the fracture mechanics and attempts to match the requirements of the fracture to the strong points of a particular spinal implant. The present algorithm for the treatment of thoracolumbar fractures is presented, and its efficacy is demonstrated by comparing it with an evolutionary group of spinal fractures cases

Biomechanical Phenomena↗
PubMed1985

Topics of interest in pediatric orthopedics.

This two-in-one article presents an overview of septic arthritis of the hip and school screening for adolescent idiopathic scoliosis--two problems commonly shared by the pediatrician and the pediatric orthopedic surgeon. The importance of aggressive diagnostic measures and treatment for the septic hip is emphasized and the basis for the rationale is given. In the section on scoliosis, the reader is introduced to the "scoliometer," and a rationale for management of most of these children by the primary physician is given.

Adolescent↗
PubMed1985

A biomechanical study of thoracolumbar spine fractures with bone in the canal. Part III. Mechanical properties of the dura and its tethering ligaments.

Experiments were performed to determine some mechanical properties of the spinal cord-meningeal (SCM) complex and its tethering elements with reference to factors contributing to contact pressure of an anterior mass on the SCM complex with spinal fracture and the development of some means to relieve the pressure. Measurements were made using a combined microload cell and displacement transducer that was passed posteriorly through a hole drilled in vertebra T12 through the interpedicular space and contacted the cord. Loss of nerve roots and anterior ligaments as dural tethers in the lumbar region permitted the SCM complex to fall out of the lordosis of the canal and fail to resist transverse loading. Head and neck flexion increased contact force for a given depth of penetration, particularly in the cervical region. This was consistent with measurements of strain along the dura that was greatest in the cervical region. The dura was found to be elastic, having a failure strain averaging 34% but was uniform in thickness, stiffness, and elastic modulus along its length. The study did not delineate any surgical manipulation other than removal of the anterior mass that would be beneficial when there is anterior compression of the spinal cord.

Biomechanical Phenomena↗
PubMed1984

Response of marine bacterioplankton to differential filtration and confinement.

The bacterioplankton community of confined seawater at 25 degrees C changed significantly within 16 h of collection. Confinement increased CFU, total cell number (by epifluorescence microscopy), and average cell volume of bacterioplankton and increased the turnover rate of amino acids in seawater sampled at Frying Pan Shoals, N.C. The bacterioplankton community was characterized by two components: differential doubling times during confinement shifted dominance from bacteria which were nonculturable to bacteria which were culturable on a complex nutrient medium. Culturable cells (especially those of the genera Pseudomonas, Alcaligenes, and Acinetobacter) increased from 0.08% of the total cell number in the seawater immediately after collection to 13% at 16 h and 41% at 32 h of confinement. Differential filtration before confinement indicated that particles passing through a 3.9-microns-, but retained by a 0.2-micron-, pore-size Nuclepore filter may be a major source of primary amines to the confined population. The 3.0-microns filtration increased growth rate and ultimate numbers of culturable cells through the removal of bacterial predators or the release of primary amines from cells damaged during filtration or both.

Amines↗
PubMed1984

A mechanistic classification of thoracolumbar spine fractures.

Thoracolumbar spinal injuries are classified on the basis of the mechanical mode of failure of the vertebral bodies. The fractures are presented in seven categories. Emphasis is placed on the injury component causing the fracture patterns. The choice of instrumentation for surgery is based on the surgeon's understanding of these injury patterns.

Fracture Fixation, Internal↗
PubMed1983

Physiologic tremor and microsurgery.

Physiologic tremor hampers the ability of students to learn microsurgical technique. An understanding of normal tremor both as to origin and methods of control would be of help. Physiological tremor arises from both mechanical and neuromuscular sources and is made worse by a number of factors. The "size principle of motoneuron recruitment" is an important physiologic consideration, and the use of biofeedback techniques enables the student to confirm his understanding of the principle. Knowledge of the factors which aggravate physiological tremor allows the microsurgeon to control his own tremor both in the laboratory and in the operating room.

Biomechanical Phenomena↗
PubMed1983

Staged correction of neuromuscular scoliosis.

Anterior release and fusion, combined with tong gravity traction and second stage L-rod instrumentation, establishes correctability and accomplishes circumferential arthrodesis of the spine in neuromuscular scoliosis. From March 1979 through April 1982, nine patients with neuromuscular scoliosis, with an average age of 16.4 years, underwent this two-stage surgical procedure. The parameters investigated included correction of scoliotic deformity, correction of pelvic decompensation, and spinal arthrodesis. The preoperative scoliotic curvature measured 81 degrees and the postoperative curve measured 29.3 degrees, an average correction of 63.8%. Pelvic obliquity was significant in five of nine patients, averaging 36.2 degrees preoperatively. Postoperatively the pelvic obliquity averaged 11.8 degrees, an average correction of 67.4%. One of two pelvic fixation rods rotated out of the pelvis of one patient; roentgenographically he appears to have fused without loss of correction. A second patient has a poor fusion mass by roentgenographic criteria, although she has lost no correction and has had no pain. This technique offers results comparable to other series reporting arthrodesis for neuromuscular scoliosis. It has the advantages of requiring no anterior instrumentation and no postoperative immobilization.

Adolescent↗
PubMed1983

The technique of scoliosis revision surgery utilizing L-rod instrumentation.

Operative treatment of failed scoliosis surgery requires an instrumentation that is readily adaptable to the multiple causes and sequelae of failed spinal surgery. A "modified L-rod" technique is described for segmental spinal instrumentation to treat failed scoliosis surgery. Nine patients underwent 10 scoliosis revision operations, with an average follow-up of 37.1 months. Three neuromuscular, five idiopathic, and one congenital scoliosis were revised. The average blood loss for the L-rod instrumentation was 2,960 ml, and the average operative time was 6.2 h. Four patients had attempted correction of their deformities, with 21.2% improvement. Five cases had triangular base-transverse bar pelvic fixation. None of the 10 revisions had pseudarthrosis at follow-up. No postoperative immobilization was used. Complications included one fracture of a fusion mass below the L-rods, penetration of the skin by a prominent wire with subsequent infection, minimal loss of correction in one case, and one broken wire without loss of correction.

Adolescent↗
PubMed1982

L-rod instrumentation for scoliosis in cerebral palsy.

From April 1977 through September 1980 at the University of Texas Medical Branch, 10 cerebral palsied individuals with total body involvement were surgically treated for their scoliosis. Each underwent L-rod instrumentation either as a definitive procedure or as the second surgery in a two-staged correction and arthrodesis. The average age of the group was 15.6 years and the average curve severity 70.8 degrees. An average correction of 59.9% or 41.5 degrees was obtained; two-stage procedures averaged 7.2 degrees correction per segment as contrasted with 5.4 degrees for single stage surgery. Most patients had regained their preoperative level of function within 2 weeks after L-rod instrumentation. At an average follow-up interval of 2.73 years, all have a solid spinal arthrodesis. On the basis of this experience, we feel that L-rod instrumentation is a more effective adjunct in the surgical management of cerebral palsy scoliosis than combined Harrington-Dwyer instrumentations.

Adolescent↗
PubMed1980

Beta thalassemia minor and cleidocranial dysplasia: a rare combination of genetic abnormalities in one family.

Dentists frequently treat patients who have several coexisting disease processes. When genetic disorders of distinct and separate types are present in several members of one family, it is a finding of considerable interest. A family afflicted with beta thalassemia minor and cleidocranial dysplasia is discussed and their management is presented. Special emphasis must be placed on the inclusion of genetic counseling in the treatment plan of patients with genetically transmissible abnormalities.

Adult↗