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Biomedical subjects

P H Lander

Publications and source records attributed to P H Lander.

11 recordsLinked to original sources
PubMed1998

Positionally dependent spinal stenosis: correlation of upright flexion-extension myelography and computed tomographic myelography.

OBJECTIVE: Upright flexion-extension myelography has shown marked variation in the severity of lumbar dural sac stenosis during flexion and extension in some patients ("positionally dependent" stenosis). Axial computed tomography (CT) of the lumbar spine while the patient is supine may not demonstrate the maximal spinal stenosis shown by flexion-extension myelography. This study compares the severity of central lumbar spinal stenosis on CT myelograms and on upright flexion-extension myelograms in patients with positionally dependent spinal stenosis. PATIENTS AND METHODS: From January 1995 to December 1996, 210 patients underwent upright flexion-extension lumbar myelography for the assessment of back pain, radiculopathy or neurogenic claudication. In 33 of these patients (in whom 39 lumbar levels were seen) there was a difference of 30% or more in the diameter of the dural sac seen on anteroposterior lateral myelograms during flexion and extension. These findings were compared with the dural sac compression shown on the CT myelograms for these patients. RESULTS: In 10 of the 33 patients (12 levels), the CT myelogram underestimated spinal stenosis, as compared with the upright flexion-extension myelogram. In 5 levels, stenosis of 70% or more seen on flexion-extension myelography was measured as 50% or less on CT myelography. CONCLUSION: In patients with positionally dependent spinal stenosis, CT myelograms may underestimate the severity of the spinal stenosis, compared with upright flexion-extension myelograms. While upright flexion-extension myelography is not a first-line imaging modality for patients with spinal stenosis, it should be considered for patients whose symptoms are not explained by routine cross-sectional imaging studies to exclude positionally dependent spinal stenosis.

Adult↗
PubMed1996

Clinical efficacy of imaging modalities in the diagnosis of low-back pain disorders.

This review provides methodological background and some guidelines for the evaluation of imaging modalities for the lumbar spine and reviews the current literature on the basis of different levels of efficacy which consider standards beyond technical quality or diagnostic accuracy. From a MEDLINE search, 672 articles (1985-1995) were retrieved which focused on the development or application of imaging modalities for lumbar spinal disorders. The papers were categorized according to different efficacy levels at which the imaging modalities were assessed. This review has demonstrated that the vast majority of reports evaluate imaging studies for the lumbar spine only at the technical efficacy level. A minor proportion of the articles focus on the evaluation at the level of diagnostic accuracy. Articles which assess imaging studies on a higher level of efficacy (e.g., diagnostic and therapeutic impact, patient outcome and cost-benefit analysis) are sparse. This review has outlined frequent methodological flaws in patient selection and design of imaging studies for the lumbar spine. The spine specialist should therefore become very critical in the interpretation of those studies and pay attention to patient selection and spectrum, choice of the reference standard, sample size, various forms of biases, and the reasoning behind clinical recommendations in order to improve his patient care.

Bias↗
PubMed1990

Imaging of the facet joints.

Facet joints have a variable anatomic orientation, and their imaging must be adapted to this variation. They have an important role in the stability and mobility of the spine at all levels. They are the sites of microtrauma leading to degenerative changes. Trauma may cause subluxation, dislocation, and fracture. As synovial joints, they manifest inflammatory processes and can present as part of a systemic disease. The facet joints are a component of a trijoint complex at each motion segment and cannot be separated biomechanically. Their visualization and analysis must be integrated with the adjoining soft tissue, and with neural and bone components.

Diagnostic Imaging↗
PubMed1986

Subperiosteal osteoid osteoma of the talus.

We report three patients with subperiosteal osteoid osteoma of the talus. All showed an erosion of the dorsal surface of the talus with medullary bone sclerosis. Adjacent paraosseous soft tissue calcification was seen in two lesions. Computed tomography demonstrated the nidus of the osteoid osteoma in two cases.

Adolescent↗
PubMed1986

Paget disease with contraction of long bones.

The evolution of Paget disease characterized both by expansion and subsequent contraction of the long bones of the ipsilateral upper extremity over a 10-year period is described.

Female↗
PubMed1986

Paget disease of the spine: CT with clinical correlation.

Thirty-six patients with pagetic involvement of the spine were evaluated clinically and by computed tomography (CT). Pagetic phase, modeling expansion, degree and site of spinal stenosis, and pagetic facet joint arthropathy were recorded for each involved vertebral segment. CT demonstrated spinal stenosis in 20 patients, 11 of whom exhibited spinal stenosis on plain films. Twenty-one patients had symptoms of neck or back pain, with associated neurologic dysfunction in 13. Spinal stenosis was present in 81% of the symptomatic patients and 20% of the asymptomatic patients. Severe pagetic facet arthropathy was present in 17 of the symptomatic patients. We conclude that spinal stenosis is an important cause of vertebral pain and neurologic dysfunction.

Aged↗
PubMed1986

A dynamic classification of Paget's disease.

A new dynamic classification of Paget's disease is proposed, incorporating both the radiographic phases of bone remodelling and the scintigraphic findings. Osteolytic, mixed and osteoblastic phases are associated with increased scintigraphic activity, while the osteosclerotic phase of remodelling is associated with normal or diminished activity and an osteoblastic radiographic appearance. Abnormal modelling of bone leading to deformity is produced by accelerated apposition or absorption at the periosteal and endosteal envelopes of the bone. In 112 patients with symptoms from Paget's disease, 527 lesions were classified. The most frequent remodelling phase was the mixed one and the most common modelling state was bone expansion with endosteal and periosteal apposition. Of 88 patients treated medically, 12 had lesions which progressed to increased bone formation without a change in modelling, and the active lesions in seven patients became inactive. Prolonged treatment with disodium etidronate led to progressive osteopenia in 11 patients.

Bone and Bones↗
PubMed1985

Spontaneous stress fractures of the femoral neck.

The diagnosis of spontaneous stress fractures of the femoral neck, a form of insufficiency stress fracture, can be missed easily. Patients present with unremitting hip pain without a history of significant trauma or unusual increase in daily activity. The initial radiographic features include osteoporosis, minor alterations of trabecular alignment, minimal extracortical or endosteal reaction, and lucent fracture lines. Initial scintigraphic examinations performed in three of four patients showed focal increased radionuclide uptake in two and no focal abnormality in one. Emphasis is placed on the paucity of early findings. Evaluation of patients with persistent hip pain requires a high degree of clinical suspicion and close follow-up; the sequelae of undetected spontaneous fractures are subcapital fracture with displacement, angular deformity, and avascular necrosis of the femoral head.

Aged↗
PubMed1985

Soft-tissue chondromas.

Soft-tissue chondromas are benign, relatively rare lesions. The clinicopathologic and radiologic features in six cases are presented and the literature is reviewed. Five of six cases had calcifications. Peripheral curvilinear calcification was seen in two cases, multiple ringlike areas characteristic of cartilage in one, and discrete ossification in another. Histopathologically, they were diverse, ranging from an immature pattern with a preponderance of chondroblasts to a more mature form with chondrocytes. Although these lesions resemble a wide variety of other soft-tissue lesions, they can usually be differentiated by their small size, characteristic location in the extremities, the nature of their calcifications, and the histopathologic features. The importance of this lesion is that it is benign. It must be distinguished from more aggressive soft-tissue neoplasms such as soft-tissue chondrosarcoma so as to spare the patient unnecessary radical therapy.

Adolescent↗