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Biomedical subjects

W J Montgomery

Publications and source records attributed to W J Montgomery.

At least 19 recordsLinked to original sources
PubMed1996

Percutaneous lumbosacral fixation and fusion: anatomic study and two-year experience with a new method.

This anatomic and clinical study describes a transsacral, percutaneous approach for fixation and fusion of the L5-S1 disc. A tunnel is created into the L5-S1 disc from this approach, permitting disc removal, bone grafting, and placement of two nine-millimeter diameter titanium screws into the body of L5. There were no complications referable to screw placement, and eight of nine patients had successful fusion.

Adult↗
PubMed1995

Principles and imaging of spinal instrumentation.

This articles focuses on the principles of spinal surgery, the basic types of spinal instrumentation, and imaging of the postoperative spine. It is the first of three articles in this issue that discuss the spine. Complications are discussed and illustrated throughout. This article should assist radiologists in the review of spinal, chest, and abdominal films of spinal surgery patients.

Equipment Failure↗
PubMed1995

Fixation techniques and instrumentation used in the cervical spine.

This article emphasizes the techniques and instrumentation used in the cervical spine to provide insight into the identification and function of the fixation, grafting, and wiring techniques used for stabilization and fusion. Fracture reduction and stabilization in degenerative disease, the most common reasons for spinal fixation in the cervical spine, are discussed, as are infections, spinal stenosis, and tumors.

Cervical Vertebrae↗
PubMed1995

Fixation techniques and instrumentation used in the thoracic, lumbar, and lumbosacral spine.

The radiologist is faced with continual changes in both surgical techniques and instrumentation for the spine. To properly evaluate radiographic and special imaging studies, it is necessary to have a working knowledge of the devices used and the principles that direct their use. This article discusses the identification and function of the most common instrumentation in the thoracic, lumbar, and lumbosacral spine.

Humans↗
PubMed1994

Relationship of the pelvic angle to the sacral angle: measurement of clinical reliability and validity.

There is a need to better document the reliability and validity of assessment measures used in physical therapy. Studies documenting the reliability of measurement of the pelvic angle and its relationship to sacral motion are presently inconclusive. The purpose of this study was twofold. First, we wanted to determine the reliability and validity of a goniometric measurement of the pelvic angle. We also wanted to test the hypothesis that there is a relationship between the pelvic angle and the sacral angle. Intertester and intratester reliability of goniometric pelvic angle measurements of 23 healthy young adults were examined using three different raters. Radiographic measurements of the pelvic and sacral angle using two raters and goniometric measurement of the pelvic angle using a single rater were taken from 15 patients with low back pain who had been referred for X-rays. Intraclass correlation coefficients (ICCs) of intratester reliability for goniometric measurements of the pelvic angle were .93, .96, and .96. The intertester reliability was .95. The ICCs for intratester reliability for radiological measurements were .92 and .95 for the sacral angle and .98 for both measurements of the pelvic angle. Intertester reliability coefficients were .86 and .88, respectively. The Pearson correlation coefficients for the goniometric and radiological measurements of the pelvic angle were .85 and .68. A comparison of the radiological and goniometric measurements of the pelvic angle with the sacral angle demonstrated low average correlations of .43 and .58, respectively. The results indicate a high level of correlation between and within testers for goniometric measurements of the pelvic angle but only a fair correlation between goniometric and radiological measurements of the pelvic angle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Spinal fixation. Part 1. Principles, basic hardware, and fixation techniques for the cervical spine.

Spinal fixation devices provide stability and restore anatomic alignment in the treatment of fractures, degenerative disease, infection, and tumors and correct congenital deformities such as those seen in scoliosis. The devices provide immediate stability but are not strong enough to withstand prolonged stress and eventually fail, in most cases, if bone fusion does not occur. Bone graft material is often used to promote fusion and to replace bone after resection. Internal fixation is used to maintain position and alignment and to prevent motion as the spine fuses. Plates and rods are attached to the vertebral body or posterior elements with wire, screws, and hooks. Screws and wire can also be used alone as a means of fixation. Surgical techniques and instrumentation have advanced in recent years, and radiologists are exposed to a myriad of devices. They need to be able to identify the various plates, screws, wiring techniques, and grafts used most commonly and to understand their function in the cervical spine for fusions and treatment of fractures and degenerative disease.

Cervical Vertebrae↗
PubMed1993

Spinal fixation. Part 2. Fixation techniques and hardware for the thoracic and lumbosacral spine.

Spinal fixation devices are used in the thoracic and lumbosacral spine to stabilize the spine, reduce deformities and fractures, and replace abnormal vertebrae. A bone fusion is usually attempted along with placement of the instrumentation because in most cases the hardware would eventually fail if it were used alone. The thoracolumbar spine is inherently unstable, and early operative intervention improves mobilization and rehabilitation. In some cases of lumbar spinal pain, surgical intervention is necessary for the treatment of conditions such as herniated disks, spondylolysis with spondylolisthesis, and degenerative disease with scoliosis. Surgical procedures consist of posterior (posterior elements) and anterior (vertebral body) fixation. Radiologists face continual changes in both surgical technique and instrumentation and should be knowledgeable about the devices available and the biomechanical principles that direct their use. They need to work with their surgical colleagues to become familiar with the techniques used at their institutions.

Humans↗
PubMed1993

Spinal fixation. Part 3. Complications of spinal instrumentation.

Spinal fixation devices can be used to form a rigid construct with the spine to replace bone, restore alignment, maintain position, and prevent motion in the treatment of fractures, degenerative disease, neoplasm, and congenital deformities. Because most spinal constructs will eventually fail if bone fusion does not occur, bone graft material is often used along with the implant to promote fusion. Conventional radiographs, obtained in two projections, remain the mainstay of implant evaluation, demonstrating the position of the spinal elements, hardware, graft material, and evidence of complication. Possible complications connected with use of fixation devices include intraoperative soft-tissue injuries, postoperative hematomas, and infection. The components (through incorrect use, malpositioning at surgery, and later dislodgment or fracture) may also contribute to complications such as instability; failure of fusion; or pain, with possible resultant neurologic damage. Bone graft material can migrate or hypertrophy, resulting in impingement on the spinal canal or neural foramen. Radiologists should be familiar with the various spinal fixation devices and techniques to better identify evolving complications.

Adult↗
PubMed1991

Orthopedic fixation devices.

Orthopedic fixation devices are used in the treatment of fractures, soft-tissue injuries, and reconstructive surgery. After fracture reduction, internal, external, or intramedullary fixation devices may be used to provide stability and maintain the alignment of bone fragments during the healing process. They must be strong and secure enough to allow early mobilization of the injured part, as well as the entire patient. Compression is used whenever possible to increase the contact area and the stability between fragments and to decrease the stress on the implant. Screws are used primarily to provide interfragmental compression or to attach plates, which can then provide compression, prevent displacement, and support the fragments during healing. Pins and wires can be used for fixation of small fragments or fractures in small bones and for attachment of external fixation devices and traction. A basic understanding of the devices and principles of use is needed to interpret radiographs obtained after the treatment of musculoskeletal injuries.

Fracture Fixation↗
PubMed1990

Reflex sympathetic dystrophy in children.

Reflex sympathetic dystrophy (RSD) is an uncommonly reported entity in children. This paper reports five cases of RSD in children and summarizes 80 cases of pediatric RSD reported in the literature. The diagnosis is based on the clinical findings of pain, dysesthesia, and autonomic instability. Tache cérébrale, not previously described in the diagnosis of RSD, is a helpful sign of vasomotor dysfunction. RSD in childhood frequently affects the lower extremities, in contrast to the adult localization around the shoulders and hands. Noninvasive, nonpharmacologic management is generally successful. A simple outpatient program of massage and mobilization was beneficial in four of the five patients treated in this study.

Adolescent↗
PubMed1989

Cross-institutional stability of behavioral criteria desirable for success in radiology residency.

Certain dimensions of job performance are critical to radiology residents, and several of these dimensions are noncognitive in nature (eg, interpersonal skills, conscientiousness, recognition of limits). Our initial study examined these factors in only one residency program, so the general nature of these dimensions must be documented. The current study was a cross institutional analysis involving 31 faculty radiologists at three separate academic institutions (82% of total faculty) who participated in a critical incident interview to obtain data on important resident behaviors and attitudes. The resultant 172 incidents were sorted by two physicians into the six categories (knowledge, technical skills, attitudes toward self and [both recognitions of limits and confidence in abilities], conscientiousness, curiosity, and interpersonal skills); inter-rater reliability was 92%, kappa = .89. A Chi square analysis revealed similar distributions of incidents across categories (x2 12 = 17.22) among the three institutions, supporting the general reliability of these dimensions across the institutions studied. Further, the distributions of these incidents demonstrated that the noncognitive dimensions again were given considerable importance by faculty radiologists. For example, more than 40% of the critical incidents pertained to the conscientiousness dimension. These findings documented the generalization of these behavioral dimensions across several sites and support their importance in selection and evaluation of residents.

Attitude of Health Personnel↗
PubMed1989

Detection of osteomyelitis at fracture nonunion sites: comparison of two scintigraphic methods.

Forty-nine patients with 50 fracture nonunions 4-48 months after injury underwent technetium-99m methylene diphosphonate (99mTc-MDP) scintigraphy on day 1, combined 99mTc-MDP and indium-111 leukocyte (111In-WBC) scintigraphy on day 2, and gallium-67 (67Ga) scintigraphy on day 3. The results were compared to evaluate the relative abilities of these scintigraphic techniques to detect osteomyelitis. Nine patients had clinical evidence of infection at the time of imaging, and 40 patients (41 fractures) did not. Open-biopsy cultures were performed at all fracture sites and were positive at 21 (42%) of the 50 sites. Combined 99mTc-MDP/111In-WBC images were interpreted with the use of two criteria. A positive study by the first criterion required 111In-WBC localization in the region of the nonunion fracture. A positive study by the second criterion required 111In-WBC localization in bone at the fracture site. The first criterion yielded a sensitivity of 84%, specificity of 72%, and accuracy of 74%; the specificity improved to 97% with an accuracy of 88% when the second criterion was used. Ten (25%) of the 40 patients thought not to have osteomyelitis by clinical criteria at the time of imaging had true-positive 99mTc-MDP/111In-WBC studies by biopsy culture results. Gallium-67 studies were interpreted as nondiagnostic if localization of radioisotope at fracture sites was equal to that with 99mTc-MDP, positive if 67Ga localization was greater than that of 99mTc-MDP, and negative if it was less than that of 99mTc-MDP. Twenty-one 67Ga studies were interpreted as nondiagnostic; 11 (52%) of the 21 had culture-positive fracture sites. The accuracy of 67Ga/99mTc-MDP imaging was 39%. Combined 99mTc-MDP/111In-WBC imaging is useful in the detection of osteomyelitis at fracture nonunion sites and improves the specificity of 111In-WBC imaging by differentiating inflammation/infection in adjacent soft tissue from osteomyelitis at the fracture site. Gallium-67 with 99mTc-MDP imaging is not sufficiently reliable in this clinical setting to be useful as an indicator for osteomyelitis.

Adult↗
PubMed1988

Magnetic resonance imaging of pyomyositis.

Pyomyositis is a relatively rare entity in temperate climates. Because of its rarity and its nonspecific clinical and radiographic findings, pyomyositis may be misdiagnosed and may cause severe morbidity and mortality. We present magnetic resonance imaging findings in two cases of pyomyositis. Magnetic resonance imaging was helpful in differentiating other pathological processes from pyomyositis, outlining the extent of involvement, and localizing the fluid collection.

Adolescent↗
PubMed1988

Impact of clinical history on fracture detection with radiography.

The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information.

Fractures, Bone↗