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Biomedical subjects

H M Frost

Publications and source records attributed to H M Frost.

At least 109 records · Page 6Linked to original sources
PubMed1983

A determinant of bone architecture. The minimum effective strain.

Minimum effective strain (MES), a hypothesis since 1964, has achieved experimental support. The range is about 0.0008-0.002 unit bone surface strain. Strains below the MES apparently do not evoke adaptive architectural bone modeling, but those above it do. As a key property of living lamellar bone and its intermediary organization, MES offers the potential to predict exactly when and where mechanical loads will cause bone architectural adaptations. MES represents a step toward the goal of constructing a specific, predictive, and quantitative theory of the mechanical determinants of skeletal architecture.

Animals↗
PubMed1982

Mechanical determinants of bone modeling.

In angulated long bone malunions in children, bone architectural changes arise which act consistently in kind, location, and direction, while the associated bone strain-stress patterns become definable as qualitative differences from the norm. Comparison of such information reveals that bone architectural adaptations correlate one-to-one with dynamic flexural strain orientation and magnitude but not with any single principal stress. The above plus other facts suggest six axioms which can explain many of the observed architectural adaptations of lamellar bone in response to specific mechanical bone-loading phenomena in normal as well as pathologic states. In essence those axioms state: In growing mammals and under repetitive, uniformly oriented, nontrivial, dynamic flexural strains, all lamellar bone surfaces drift in the concave-tending direction. As a result of these strains, a bone would adopt a size and configuration that minimize its flexural deformation during normal activities. The axioms provide reasonable explanations for inwaisting of vertebral bodies and long bone metaphyses, correction of malunions, increasing outside diameter and cortical thickness during growth, circular, elliptical, and triangular cross-sections, natural curvatures of whole bones, many architectural changes due to neuromotor abnormalities arising in early life, and the more rapid modeling seen in very young children or after recent fractures.

Adult↗
PubMed1981

Clinical management of the symptomatic osteoporotic patient.

The acute skeletal disability arising in most osteoporoses of nonmalignant origin forms a self-limiting phenomenon characterized by intermittency, typically over a four-year period or less. Symptomatically, the acute disabilities that these patients suffer respond to relatively simple nonpharmacologic measures. Once one understands both the self-limiting course of the disability and the simple means of dealing with its symptoms while they last, managing these patients becomes fairly straightforward. We can summarize these means in the following four words: analgesics, rest, support, and time.

Acute Disease↗
PubMed1979

Ossification of the posterior longitudianl ligament of the cervical spine: subtotal vertebrectomy as a treatment.

If the ossification is localized in the central part of the intervertebral space, anterior decompression surgery of Cloward may be indicated. However, if most posterior ligamentous ossification covers the posterior surface of the vertebral body and the lateral sides, Cloward's method is not indicated. We have developed a method of anterior decompression and fusion surgery to clear the ossified area, resecting the vertebral body (subtotal vertebrectomy). The results were excellent in 3 of 4 patients with preoperative radiculopathy; there were 2 excellent and 16 good results in 22 patients with myelopathy. Of course laminectomy can produce some good effects, but the anterior obstruction removes through the anterior approach. Anterior decompression may be indicated when ossification is localized below the C3--4 intervertebral space, and when the spinal canal is not narrowed in the upper cervical region, even if ossification extends over the whole cervical spine. Laminectomy is advised when ossification involves all levels of the cervical spine, the upper cervical spine is narrowed or the sagittal dimension of the spinal canal is reduced more than 60%.

Cervical Vertebrae↗
PubMed1979

Treatment of osteoporoses by manipulation of coherent bone cell populations.

Up to and including the year 1979, no agent, combination of agents or other treatment has been found which, when given continuously to the intact incoherent adult human skeleton, can store in it clinically useful amounts of bone in a way which can continue with continued treatment. BMU theory suggests that failure derives from a depression by such treatments of both resorptive and formative activity, partly by depressing the naturally coupled activities of already existing 'clast and 'blast populations, and partly by reducing BMU activation. However BMU theory also suggests that selected agents given in special sequences can create a positive bone balance in repeatable increments. One such proposal, called the ADFR sequence, involves generating a pulse of increased BMU activations. The resorptive and formative activities created by that pulse will occur at predictably different periods of time, that is, they will prove coherent. By depressing the coherent resorption with a suitable agent during its lifetime, and then freeing the skeleton of treatment during the following coherent osteoblastic activity one stores an increment of new bone, because the ADF sequence causes remodeling BMU to deposit normal amounts of new bone in smaller than normal holes. The sequence is repeated as often as needed to add further increments. Other manipulations of coherent bone cell populations could remove bone or simply alter its turnover speed, as desired. Thus special sequences of simple pharmacologic actions, which have no useful ultimate effects upon global bone balance when delivered continuously and alone to the incoherent skeleton, create a simple new kind of therapy which should (and did) exert dramatic (and probably repeatably incrementable) effects in the coherent skeleton. The concept of manipulating deliberately induced coherent skeletal states for therapeutic purposes would not appear to depend for its success upon any one or 2 or even 3 special drugs.

Adult↗
PubMed1977

The surgical technique for hindquarter amputation. A report of 19 cases.

The surgical technique for hindquarter amputation is described in a step-by-step manner. Since 1955 we have performed 19 such operations for eradication of malignant bone and soft tissue tumors in the pelvic, hip and upper thigh regions. Three hindquarter amputations were performed for local recurrence following initial wide excision. The overall 5-year survival rate for our 19 patients was 42.1 per cent. Malignant soft tissue tumors appear to have a much better 5-year survival rate than malignant bone tumors (60 per cent vs. 22.2 percent). We feel that surgery is still the treatment of choice. However, in the presence of proper indications, chemotherapy and radiotherapy should be added to surgery in order to prolong survival time and save lives.

Adolescent↗