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Biomedical subjects

M F Schafer

Publications and source records attributed to M F Schafer.

16 recordsLinked to original sources
PubMed1992

Anterior cruciate ligament injury: MR imaging diagnosis and patterns of injury.

The anterior cruciate ligament (ACL) is an important stabilizer of knee motion. Injury of the ACL can lead to substantial disability; an accurate diagnosis of ACL injury is vital in both short-term and long-term patient care. Magnetic resonance (MR) imaging has emerged as the study of choice to evaluate the status of the ACL and other associated structures in the knee. Sagittal MR images have been commonly used in the evaluation of the ACL. However, the authors believe that coronal and axial imaging planes can add useful information about ACL injury and, thus, lead to improved accuracy and confidence regarding diagnosis. Multiplanar imaging can readily demonstrate meniscal, ligamentous, and bone marrow injuries that commonly occur with the most frequent mechanisms of ACL injury. These mechanisms, in order of frequency, include internal rotation and valgus stress, hyperextension, and varus stress with external rotation. An understanding of these mechanisms is helpful in the MR diagnosis of ACL injury.

Anterior Cruciate Ligament Injuries↗
PubMed1991

The natural history of congenital kyphosis in myelomeningocele. A review of 51 children.

The progression of congenital lumbar kyphosis in myelomeningocele is a well-known problem, but rates of progression are not well documented in the literature. Fifty-one children with congenital kyphosis and myelomeningocele were followed for an average of 4.8 years. Minimum follow-up was 1 year. Group I (35 patients) had initial radiographs at 1 year of age or less. Group II (16 patients) had radiographs taken after the age of 1 year. Curves less than or equal to 90 degrees in Group I progressed 7.7 degrees/yr; those greater than 90 degrees progressed 12.1 degrees/yr. Curves less than or equal to 90 degrees and greater than 90 degrees progressed at similar rates, regardless of initial curve magnitude: 6.4 degrees/yr and 6.7 degrees/yr, respectively. No correlation existed among the rate of curve progression, the frequency of shunt revisions, or the presence of vertebral anomalies, aside from the dysraphism.

Child↗
PubMed1989

Upper extremity arterial injury in athletes.

Between 1983 and 1986, 23 athletes were evaluated for arm and hand complaints. Eleven players had symptoms of thoracic outlet compression. Severe arm fatigue (eight patients) and finger ischemia (three patients) were the presenting symptoms. In the remaining 12 athletes, symptoms of hand ischemia were predominant. Noninvasive testing with Doppler ultrasonography and duplex scanning (positional testing and finger systolic pressure recording) and cold immersion were used to aid in diagnosis. In the 11 athletes with thoracic outlet compression, arteriography confirmed the finding with compression of the subclavian artery in five, the axillary artery in one, both subclavian and axillary arteries in two, posterior humeral circumflex artery in one, and subclavian aneurysm in two. Compression of the suprascapular artery was identified in four, the subscapular artery in two, and the posterior humeral circumflex artery in one. Thrombosis of a first baseman's ulnar artery and occlusion of the palmar arch in a frisbee player were documented by arteriography. Decompression of the thoracic outlet consisted of anterior scalenectomy in five, pectoralis minor muscle division in one, and resection of both muscles in two. Removal of cervical rib with interposed vein graft was performed in the two players with arterial aneurysm. Hand ischemia in the remaining athletes was treated conservatively with Dextran-heparin infusion for acute ischemia. Repeat noninvasive study of all players demonstrated absence of compression in their playing position, and all have resumed their playing careers. Hand ischemia in athletes can be evaluated noninvasively and treated conservatively. Resection of hypertrophied muscles to decompress the thoracic outlet together with release of branch artery compression in selected athletes promotes perfusion to arm and shoulder muscles and helps to avoid the catastrophic complication of repetitive trauma leading to sudden arterial thrombosis.

Adolescent↗
PubMed1986

Surgical management of adult scoliosis.

In a retrospective analysis of 62 adult scoliotic patients with an average age of 34 years, 39 patients were treated by single-stage posterior fusions, 19 by Harrington instrumentation, and 20 by Luque instrumentation. Twenty-three patients had staged scoliotic procedures. Overall there was a 47% incidence of complications, with the lowest rate, 20%, found in those patients undergoing single-stage posterior fusion with Luque instrumentation. A 16.7% incidence of pseudarthrosis was found in those patients undergoing posterior fusion with Harrington instrumentation. Pseudarthrosis was not found in patients fused posteriorly with Luque instrumentation or with staged anterior and posterior instrumentation.

Adult↗
PubMed1985

Surgical fusion of the posttraumatic spine: a radiologic assessment.

Radiological assessment of surgical fusion of fractures and dislocations of the cervical, thoracic, and lumbar spine are an integral part of management of spinal cord injury patients. A meaningful assessment of such fusions can be done properly only when there is adequate knowledge of the types of surgical fusions, the biological material used, and metallic devices applied. Early surgical reduction and internal fixation of the traumatized spine facilitate rapid restoration of spinal alignment, make nursing care less difficult, and sometimes lead toward improvement of neurological function. Complications can occur in all types of surgical fusions. They can affect the fusion material, the metallic device, or the alignment of the spine. Most of those complications are radiologically detected.

Bone Nails↗
PubMed1984

Chymopapain allergy: case reports and identification of patients at risk for chymopapain anaphylaxis.

Chymopapain has been approved for intradiscal injection in the United States and is expected to be used in approximately 100,000 patients per year. The need to identify the population at risk for anaphylaxis is obvious. Both in vivo and in vitro methods are available for measurement of IgE against chymopapain. This is a report of two cases of chymopapain allergy. One case discusses a 25-year-old woman who had rhinitis, asthma, and urticaria associated with occupational health hazards who was rejected for chemonucleolysis. The other case describes a 59-year-old man who had a predictably severe anaphylactic reaction to chymopapain and responded to treatment with epinephrine. Both patients had IgE antibody against chymopapain.

Adult↗
PubMed1978

Dwyer instrumentation of the spine.

The evolution of the Dwyer procedure during the past 10 years has enabled us to better define the indications and contraindications for the procedure. The role of the Dwyer procedure in the treatment of thoracolumbar or lumbar curves in both the adolescent and the adult has been found to be significant. When combined with Harrington rod instrumentation it can be used for either paralytic curves, curves associated with pelvic obliquity, or curves in which posterior elements are absent.

Child↗
PubMed1978

Rational approach to the differentiation of vascular and neurogenic claudication.

Lower extremity pain caused by exercise but relieved by rest is usually a reliable symptom of chronic arterial insufficiency. However, similar discomfort often occurs in patients with neurospinal compression. Furthermore, arterial occlusive disease and demonstrable spinal stenosis may be present simultaneously. Fifty-two patients with symptoms suggesting intermittent claudication comprised the study group. All were proven to have a nonarterial cause of their complaint. The study consists of a retrospective analysis of the diagnostic methods used in confirming the proper diagnosis. Conclusions reached suggest a rational approach to solution of individual patient problems. The nonvascular origin of the symptoms was suggested initially by clinical evaluation in 19 patients, and by noninvasive arterial evaluation in an additional 22. The neurospinal origin of symptoms was obscured in 11 patients because of the presence of significant arterial occlusive disease, as demonstrated by nominvasive arterial testing. Seven of the 11 patients underwent arterial reconstruction, which failed to relieve their symptoms. Subsequently, the neurospinal origin of these symptoms was proven by appropriate treatment. This experience has shown that the errors in diagnosis and treatment could have been avoided by using a combined diagnostic approach, correlating results of an accurate clinical evaluation with noninvasive arterial testing as well as the findings shown on lumbosacral spine films.

Adult↗
PubMedDate not supplied

Mechanical evaluation of the Dwyer screw-cable attachment.

A critical portion of the Dwyer technique is the crimping of the screw head to prevent the cable from slipping. Initally, Dwyer designed a hydraulic mechanism to crimp the screw head. However, this instrument was cumbersome to use and presented potential sterility problems. Today the Simmons crimper is used by the majority of orthopaedic surgeons. It is the purpose of this paper to report the studies conducted on 1) different materials used for the fabrication of the screws, and 2) the significance of the variations in the jaw opening using the Simmons mechanical crimper.

Evaluation Studies as Topic↗
PubMedDate not supplied

Arterial abnormalities of the shoulder in athletes.

Vascular lesions of the shoulder may be misinterpreted as one of the more familiar shoulder abnormalities by a treating physician. We are reporting on 13 athletes who were found to have symptoms related to compression of the subclavian or axillary artery or their tributaries. Nine were amateur or professional baseball pitchers. Severe arm fatigue or finger ischemia, secondary to embolization, were presenting symptoms. Arm fatigue was noted in all pitchers. After complete history and physical examination, including auscultation for bruits in functional positions, all athletes were evaluated by noninvasive tests (Doppler and Duplex scanning). Arteriography was performed with positional testing, recreating overhead activity, and complete radiographic visualization of the dye to the digital arteries. Two patients were found to have subclavian artery aneurysm. The remaining athletes were found to have compression of the subclavian artery beneath the anterior scalene muscle (five patients), the axillary artery beneath the pectoralis minor (two patients), both arterial segments (two patients), and one was found to have arterial compromise at the level of the humeral head. Branch artery compression was also noted. One pitcher occluded the posterior circumflex humeral artery with embolization to the digit. The two patients with subclavian aneurysms underwent saphenous vein bypass with cervical rib resection. All of the other athletes except one underwent resection of a 2 to 3 cm segment of the anterior scalene muscle or pectoralis minor muscles. All returned to their previous level of activity except one patient who developed impingement type symptoms and required acromioplasty. He is currently undergoing rehabilitation. Proper recognition of vascular compromise in the upper extremity of athletes is essential to avoid the catastropic complications of arterial thrombosis.

Athletic Injuries↗
PubMedDate not supplied

Arterial abnormalities of the hand in athletes.

Vascular lesions of the hand may be seen in athletes exposed to repetitive blunt trauma. Thirteen athletes seen from 1983 to 1988 experienced symptoms related to hand ischemia. Nine were professional baseball catchers. The majority of patients complained of chronic symptoms, including cold hypersensitivity (four patients), finger numbness (one), finger coolness (three), and finger blanching (three). Two patients had acute symptoms with sudden posttraumatic hand ischemia with finger and palmar pain. Diagnosis was established by history and physical examination and confirmed by noninvasive testing. Testing included use of Doppler examination and cold tolerance examination with thermistors. Two athletes required angiographic evaluation because of severe ischemia and continuous pain. All patients in this group were managed nonoperatively. Those with chronic complaints were counseled regarding cold avoidance and instructed to increase their glove padding. The two patients with acute symptoms required vasodilator (papaverine chloride) infusion, followed by intravenous heparin and dextran. All baseball catchers returned to their sport with dissipation of symptoms.

Arteries↗
PubMedDate not supplied

Onlay fibular bone grafting in treatment of tibial fracture non-union.

Twenty-nine patients with tibial non-union or delayed union were treated by onlay grafting, using long struts from the ipsilateral fibula and without disturbing the non-union site. Internal fixation and excessive dissection can be avoided. Follow-up in 28 patients showed solid healing in all; 20/28 patients united the fracture within 7 months. Removal of the fibula as a distracting force, combined with the principles of onlay grafting advocated by Phemister, is effective surgical treatment.

Adolescent↗