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Biomedical subjects

G L Lucas

Publications and source records attributed to G L Lucas.

At least 19 recordsLinked to original sources
PubMed2000

Construct stiffness of different fixation methods for supracondylar femoral fractures above total knee prostheses.

Supracondylar fracture of the femur after total knee arthroplasty has an estimated frequency of 0.6%-2.5% among total knee recipients and presents an extremely difficult problem when encountered. The goal of this study is to determine the most stable method of fixation of these supracondylar fractures among currently available devices. Synthetic composite femurs with properties similar to human bone were used, and identical, unstable supracondylar fractures were created in each. Osteotomized specimens were placed into four groups of five. Each group was then tested with one of four devices: the Green-Seligson-Henry (GSH) intramedullary nail, AO 95 degrees blade plate, dynamic condylar screw and sideplate, and condylar buttress plate. After stabilization with the different types of fixation, the constructs were tested individually for bending stiffness in four modes: flexion, extension, varus, and valgus bending. The stiffest fixation was determined in each of the four bending planes. Resistance to all tested directions was greatest for the condylar screw and sideplate construct. Resistance to flexion (stiffness = 30.96 N/mm), extension (stiffness = 36.36 N/mm), varus (stiffness = 35.46 N/mm), and valgus forces (stiffness = 32.26 N/mm) was highest in the group fixed with the dynamic condylar screw. This may be due to the purchase gained by the large lag screw into the distal femur, or it may be the result of the total rigidity of the implant. Although the femoral samples used in this study do not duplicate the typical osteopenic bone encountered at the site of a total knee arthroplasty, they do allow direct comparison of the fixation devices by removing the variability associated with cadaveric bone samples.

Arthroplasty, Replacement, Knee↗
PubMed1999

Epidermoid inclusion cysts of the hand.

Epidermoid inclusion cysts occur second only to ganglions in terms of tumefaction presentations in the hand. This review describes 60 such lesions and reviews the clinical presentation, diagnosis, and treatment. The epidermoid inclusion cyst probably arises from some traumatic event that drives epithelial cells into the subcutaneous tissues where they survive, grow, and produce keratin.

Adolescent↗
PubMed1998

Kinematics of the capitolunate joint in the sagittal plane. A new method based on reference points and triangulation.

A new method of assessing capitolunate alignment is presented. Three anatomical carpal reference points were evaluated on lateral radiographs using triangulation. Connecting these three points forms a triangle with dorsal, palmar and somewhat vertical sides. One hundred normal lateral wrist radiographs were measured. The overall dorsal limb (DL) to palmar limb (PL) ratio was found to be 0.74 (SD 0.07) over a range of 40 degrees extension to 42 degrees flexion. As the DL to PL ratio approached 1.0, a dorsal intercalated segment instability (DISI) deformity developed. Conversely, as the DL to PL ratio approached 0.5, a palmar intercalated segment instability (PISI) occurred. This method appears useful for evaluating static lateral radiographs for intercalary carpal alignment and possibly instability.

Adolescent↗
PubMed1997

Value of cervical spine radiographs as a screening tool.

A review of the reports of 848 cervical spine radiographs was done to assess the yield of useful and critical information in a group of patients without trauma. In 470 of these patients the clinical record also was reviewed; 54.2% of the radiographs were read as having degenerative change, 35% were read as normal, and 8.5% were read as being consistent with muscle spasm. The remaining 2.3% included diagnoses of anatomic or congenital variants, soft tissue calcification, or old compression fractures. There were no serious diagnoses such as acute fracture, dislocation, or neoplasm that, had they not been identified, would have put the patient in jeopardy. Thus, for most outpatients with nontraumatic symptoms of a nonspecific or nonlocalizing nature, the use of cervical spine radiographs as a screening tool is not justified.

Adolescent↗
PubMed1996

Fat embolism syndrome.

Since it was initially described, fat embolism syndrome (FES) has remained one of the least clearly understood complications of trauma. This article is a review of the classic and current literature on FES with regard to its causes, pathophysiology, clinical presentation, diagnosis, and treatment. FES is associated with many traumatic and nontraumatic conditions, but is most commonly associated with fractures of long bones of the lower extremity. The pathophysiology is thought to be a cascade of events which can lead to adult respiratory distress syndrome (ARDS). Signs and symptoms of clinical FES usually begin within 24 to 48 hours after trauma. The classic triad involves pulmonary changes, cerebral dysfunction, and petechial rash. Clinical diagnosis is key because laboratory and roentgenographic diagnosis is not specific. Treatment consists of careful initial handling, early stabilization of fractures, careful volume replacement, analgesia, respiratory support, and perhaps steroids. The vast majority of patients today survive FES without sequelae.

Embolism, Fat↗
PubMed1994

Orthopedic injuries from the Andover, Kansas, tornado.

Devastating tornados struck the state of Kansas on Friday, April 26, 1991. Twenty lives were lost and many people were injured. Property damage was extensive. Overall, the outcome of those admitted to the various hospitals was good, with few orthopedic-related complications. The low complication rate can be attributed to thorough open wound management and suspicion and recognition of other potential orthopedic complications such as compartment syndrome.

Abdominal Injuries↗
PubMed1993

Cervical spine evaluation: efficacy of open-mouth odontoid view for nontraumatic radiography.

PURPOSE: The open-mouth odontoid view has been a standard component of radiographic cervical spine series regardless of setting or indication. This study examines the prevalence of disease in C-1 to C-2 in an outpatient setting for nontraumatic neck evaluations. MATERIALS AND METHODS: Reports of 1,033 nontraumatic cervical spine series on file at two large medical centers and at a large multispecialty clinic were reviewed retrospectively for patient characteristics, indications, and radiologic evaluations. RESULTS: The odontoid view in 10 patients demonstrated radiographic abnormalities in C-1 to C-2. Four of these patients had rheumatoid arthritis, two had metastatic carcinoma, one had Down syndrome, and the remaining three had no predisposing conditions for disease in C-1 to C-2. CONCLUSIONS: Odontoid view radiography is warranted in patients with conditions with increased risk for disease in C-1 to C-2, but for the vast majority of outpatients it is not worth the technical difficulty, radiation exposure, or expense.

Adolescent↗
PubMed1991

Treatment results of stereotactic interstitial brachytherapy for primary and metastatic brain tumors.

A total of 41 stereotactic interstitial brain implants in 39 patients were performed for recurrence after teletherapy (recurrence implant), or as part of initial treatment in conjunction with teletherapy (primary implant). Implanted tumors consisted of malignant gliomas (33), other primary brain tumors (3), and single metastatic lesions (3). All patients were temporarily implanted with Ir-192 using a coaxial catheter afterloading system; two patients were implanted twice. Survival post-implant for glioblastoma multiforme (GBM), 13 patients, was 10 months whether implanted primarily or for recurrence. Mean time to recurrence, measured from initiation of teletherapy to implantation, was 10 months. Twenty patients with anaplastic astrocytoma (AA) had a median survival post-implant of 23 months for primary implants (7 patients) and 11 months for recurrence implants (13 patients). Mean time to recurrence, measured from initiation of teletherapy to implantation, was 19 months. Three patients (9%) of the evaluable group required reoperation for symptomatic mass effect, all with initial diagnosis of AA. Survival for this subgroup was 14, 22, and 32 months post-implantation. Using stereotactic techniques, interstitial brachytherapy of brain tumors was technically feasible with negligible acute morbidity and mortality, and appeared to offer limited prolongation of control for a subset of patients with recurrent malignant gliomas. The role of this modality in primary treatment for malignant gliomas needs to be further defined by prospectively randomized trials.

Adolescent↗
PubMed1989

Osteotomy of the metacarpals and phalanges stabilized by AO plates and screws.

Although digital or metacarpal nonunion with resultant functional disability of the hand is encountered often enough that corrective osteotomy becomes a consideration, many surgeons are reluctant to attempt osteotomy in the hand. This reluctance is reflected in the sparse number of cases reported in the literature. Since the effectiveness of AO plates and screw fixation for acute phalangeal and metacarpal fractures is well established, it seems logical to perform osteotomies in phalanges or metacarpals and stabilize them in the same fashion. We have reviewed 36 such osteotomies from the files of the AO Documentation Center. The osteotomies were done through either phalanges or metacarpals to correct angulation and/or rotary malunion, and yielded twenty-three very good, eight good and five poor results, or an overall satisfactory result rate of 86%. All osteotomy sites healed and the poor results reflect persistent deformity or limited adjacent joint motion. Thus, it appears that previously expressed pessimism regarding potential non-union or joint stiffness following phalangeal or metacarpal osteotomy is not warranted in angular and/or rotational osteotomy in the hand can yield satisfactory results in a very high percentage of patients.

Adolescent↗