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Biomedical subjects

H M Rosen

Publications and source records attributed to H M Rosen.

17 recordsLinked to original sources
PubMed1992

Facial skeletal expansion: treatment strategies and rationale.

Forty-three nonconsecutive patients presenting with dentofacial deformity underwent surgical procedures designed intentionally to create skeletal disproportion in the sagittal and/or vertical dimensions. This was accomplished through expansion (enlargement) of the facial skeleton beyond normative standards. At the time of follow-up, which ranged from 14 to 36 months (mean 18.4 months), soft-tissue cephalometric analyses documented facial disproportion to exist in 37 of the 43 patients treated. Thirty-two patients had excessive anterior divergence (facial protrusion) at pogonion, and 17 patients had excessive lower face height as measured from subnasale to menton. All patients were judged to have had a favorable aesthetic outcome. This philosophy of facial skeletal expansion is predicated on two concepts: The first of these is that facial proportions and dimensions beyond those which are considered normal may be extremely attractive in a given individual. Second, the soft-tissue response to skeletal expansion is more favorable and predictable than it is to skeletal contraction in providing for well-supported soft tissues. This treatment planning approach is based on the dynamic interrelationship between the skeletal foundation and the soft-tissue facial mask. It relies on physical examination as the major determinant of aesthetic surgical options.

Adolescent↗
PubMed1991

Porous block hydroxyapatite in orthognathic surgery.

Seventy-six nonconsecutive patients undergoing orthognathic surgery, in whom blocks of porous hydroxyapatite were implanted into osteotomy gaps in lieu of autogenous bone grafts, are the subjects of this report. Surgical procedures include inferior maxillary repositioning (10 patients), maxillary advancement (24 patients), transverse maxillary expansions (17 patients) and inferior repositioning of the chin (25 patients). A total of 140 anatomic sites were implanted. Eleven patients later consented to open biopsy of the implant material at a mean 10.2 months following implantation. At the time of follow-up, mean 16.3 months, excellent osseous stability was observed. Three patients developed complications relative to the presence of the implant. Twenty-one of 24 biopsy specimens demonstrated an osseous union of implant to bone with osseous deposition within the implant pores. Radiographic follow-up revealed implant blocks to maintain their volume with no change in density or discreteness. The biological behavior and biomechanical properties of porous block hydroxyapatite are discussed. These implant characteristics make it a feasible bone graft substitute in orthognathic surgery and justify its continued use in this context.

Adolescent↗
PubMed1991

Maxillary advancement for mandibular prognathism: indications and rationale.

The surgical correction of mandibular prognathism has traditionally involved posterior repositioning of the mandibular body. This treatment approach corrects the skeletal disproportion at the expense of reducing facial skeletal volume and can unpredictably result in inadequately supported soft tissues with loss of skeletal definition. In an effort to avoid these sequelae of mandibular reduction, 18 patients diagnosed as having mandibular prognathism were treated with maxillary advancement surgery at the Le Fort I level. Mean patient SNB angle was 85.2 degrees, as compared with a normal 79 +/- 3 degrees. Maxillae were documented to be in normal position relative to both cranial base and Frankfort horizontal. The mean maxillary advancement was 6.9 mm, with a range of 4.5 to 8.8 mm. All patients required genioplasty to reduce vertical chin height and/or to laterally shift the chin. At the time of follow-up (mean 16.2 months), all patients retained cephalometric data suggestive of enlarged mandibles and excessive anterior facial divergence. However, maxillomandibular harmony and facial convexity had been restored without sacrificing skeletal volume. Treatment results demonstrated these faces to be skeletally well proportioned despite lower face protrusion that was beyond "normal." Postoperative appearances were characterized by a well-supported soft-tissue envelope and a highlighted skeletal foundation, creating angular, well-defined lower faces. These findings support the credibility of maxillary advancement as the procedure of choice in selected individuals with mandibular prognathism. Indications and an aesthetic rationale for this surgical approach are presented.

Adolescent↗
PubMed1991

Aesthetic refinements in genioplasty: the role of the labiomental fold.

The vast majority of patients requesting aesthetic enlargement of their chins have a class II skeletal deformity secondary to a small mandible. Class II skeletal patterns are frequently associated with abnormalities of lower face height, which, in turn, affect labiomental fold morphology. Of 68 patients who were to undergo sagittal advancement of their chins, 88 percent were considered to have abnormal labiomental fold morphology that was closely related to abnormalities of the facial height. Patients with decreased lower face height (40 percent) had exaggerated, deepened folds with acutely closed angles between the lower lip and chin pad, whereas those with increased lower face height (25 percent) had shallow, effaced folds. Patients with normal lower face height had variable fold morphology. Isolated sagittal advancement and/or simultaneous advancement and vertical shortening deepened the labiomental fold and closed the angle between the chin pad and lower lip. Simultaneous advancement and lengthening tended to deemphasize the fold, making it appear less deep in 20 of 34 patients, or at least mitigated further accentuation of the fold in 14 of 34 patients. Altered labiomental morphology and its relationship to the class II skeletal deformity is discussed. Treatment planning decisions are suggested, taking into account labiomental aesthetics and how they are influenced by advancement genioplasty.

Adult↗
PubMed1991

The response of porous hydroxyapatite to contiguous tissue infection.

Two patients are presented in whom severe clinical infection developed in tissue adjacent to and contiguous with previously implanted blocks of porous hydroxyapatite. Both infections resolved with appropriate antibiotics, debridement, and drainage of infected tissues. Hydroxyapatite blocks were left in situ. This unusually favorable response of an alloplast to infection is attributable to the abundant vascular supply of this porous implant. Although reliable dogma can hardly be concluded from two clinical examples, these experiences suggest that once ingrown, porous hydroxyapatite does not behave in a fashion that is typical of foreign bodies in the midst of infection. For the first time, clinical evidence has been offered to support the experimental data that vascularized hydroxyapatite has the ability to resist infection.

Adolescent↗
PubMed1991

When osteotomies should be considered.

Osteotomy at various levels of the facial skeleton is entirely justified in selected aesthetic surgical patients. By the very nature of aesthetic surgery, the morbidity potential associated with such osteotomies must be extremely low. Accordingly, osteotomy at the symphyseal level and the LeFort I level are the most commonly performed procedures in the aesthetic surgical patient. Aesthetic changes required in the vertical plane of space will require osteotomy, because these cannot be reliably and consistently achieved through changes in skeletal surface contour. Lastly, when the extent of change required is greater than what can be naturally achieved with surface augmentation, osteotomy must be considered. This last indication is frequently found in the aesthetic surgical patient presenting with a facial skeletal imbalance that has been previously treated with orthodontics to correct a skeletally based malocclusion. Recent technical advances have markedly reduced the associated morbidity of facial osteotomies and, therefore, have made this treatment option more acceptable to aesthetic surgical patients. Ceramic orthodontic brackets and surgical hooks and lingual orthodontic appliances have made presurgical orthodontic preparation more aesthetic and socially acceptable for LeFort I osteotomy patients. The use of rigid fixation, obviating the need for any postoperative intermaxillary fixation, has also made this treatment approach more appealing to aesthetic patients. Lastly, the efficacy of nonresorbable bone substitutes--in particular, porous, block hydroxyapatite--has, to a significant extent, obviated the need for harvesting autogenous bone grafts, further reducing surgical morbidity.

Face↗
PubMed1978

Influences of exogenous intake and nitrogen balance on plasma and brain aromatic amino acid concentrations.

In an effort to determine the sum of the factors influencing the plasma and brain concentrations of aromatic amino acids in rats with liver disease, rats with end-to-side portacaval shunts and their sham-operated controls were placed on various oral and intravenous diets by the techniques of parenteral nutrition. In sham-operated animals with normal hepatic function, the source of amino acids and their composition appeared to play little role in the plasma and brain aromatic amino acids and a derivative of brain tyrosine, octopamine. After end-to-side portacaval shunt, however, plasma and brain concentrations of aromatic amino acids were responsive to exogenous intake in the presence of hepatic impairment. In a group of rats with end-to-side portacaval shunt and presumed hepatic impairment, graded increments of protein equivalent were given with isocaloric hypertonic dextrose by the techniques of parenteral nutrition. When the animals achieved positive nitrogen balance, there were decreased levels in plasma and brain of the aromatic amino acids, phenylalanine and tyrosine, and a derivative of tyrosine, octopamine. A clear statistical relationship between plasma and brain tryptophan and nitrogen balance was not observed. The results suggest that in animals with hepatic impairment secondary to end-to-side portacaval shunt both exogenous intake and the level of catabolism (nitrogen balance) influence plasma and brain aromatic amino acids.

Amino Acids↗
PubMed1978

The inclusion of capitation reimbursement in solo practice.

Capitation reimbursement has been an integral part of prepaid group practices in both medicine and dentistry, and claims have been made for its ability to influence the delivery of services favorably. Experts have suggested that if capitation is implemented, more preventive care will be provided, more diagnostic services will be provided, there will be better continuity of care, utilization of high-cost services will be reduced, and clinical outcome will be improved. This study focused on the dominant mode of practice in dentistry, the general, solo practitioner, to determine if these contentions held. A sample of 245 patients whose care was paid for by a capitation mechanism was matched to a sample of 245 similar patients whose care was paid for on a standard fee-for-service basis--all from three dentists' practices. All services in all years of care for each patient were analyzed. It was determined that the rate of restorations was lower, while rates of diagnostic testing and prophylaxis were higher for capitation patients. Continuity was also better under capitation, but rates of extractions were virtually identical for the two groups.

Capitation Fee↗
PubMed1977

Physician participation in health administrator education.

A seminar in quality of care analysis was developed with three objectives in mind: (a) to familiarize health administration students with methods for measuring the quality of health care (b), to sensitize students to complexities of the medical care process, and (c) to provide a setting where students interact directly with physicians in dealing with a common problem. Students developed individual evaluation projects at participating institutions in cooperation with faculty of the program and staff at the institutions. Evaluation of the seminar in terms of state objectives was performed both quantitatively and qualitatively. Indications are that the course was well accepted by students and achieved its major goals.

Child↗
PubMed1977

Plasma amino acid patterns in hepatic encephalopathy of differing etiology.

Plasma amino acids were measured in 18 patients with hepatic encephalopathy on a protein-restricted diet of 20 g or less daily. Plasma aminograms tended to group into two distinct patterns depending on the etiology of the patients' hepatic pathology. Patients with chronic liver disease with superimposed acute insults, i.e., gastrointestinal bleeding, infection, alcoholic hepatitis, had elevated levels of the aromatic amino acids, phenylalanine, tyrosine, and tryptophan, as well as methionine, glutamate, and aspartate, whereas levels of the branched chain amino acids, valine, leucine, and isoleucine, were consistently depressed. Those patients with previously normal livers and acute hepatic necrosis, i.e., "fulminant hepatitis," had grossly elevated levels of all amino acids except the branched chain amino acids, which were normal. Elevations of amino acid levels in this patient group tended to correlate with extent of hepatic necrosis and hence had prognostic significance. Additionally, the different patterns seen in these two groups tend to suggest the indicated therapy as well as predict its efficacy.

Acute Disease↗
PubMed1977

Capitation in dentistry: a quasi-experimental evaluation.

Two matched samples of 245 patients were drawn from solo dental practices which contained both capitation and fee-for-service components. All services rendered to patients during their entire time under care of the practice were recorded and analyzed. Results indicate different styles of care under the two payment mechanisms. An improved preventive style was associated with capitation, as well as fewer fillings. Outcome measured by a modification of the DMF (decayed-missing-filled) Index was also more favorable under capitation.

Adolescent↗
PubMed1976

The effect of normalization of plasma amino acids on hepatic encephalopathy in man.

Previous work from this laboratory has suggested that the plasma amino acid pattern, known to be deranged in hepatic encephalopathy, may be related causally. In order to test this hypothesis, 23% dextrose and a special amino acid solution whose components were calculated to normalize the plasma amino acid pattern were infused in 11 patients, eight with chronic cirrhosis and acute exacerbation (Group 1) and three patients with fulminant hepatitis (Group 2), in amounts of up to 120 Gm. of protein equivalent per 24 hours. Plasma amino acids were abnormal but different in both groups. In Group 1 (cirrhosis) changes in plasma amino acid pattern including elevated phenylalanine, tyrosine, glutamate, aspartate, and methionine and decreased valine, leucine, and isoleucine. In Group 2 all amino acids were elevated, with the exception of the branched chains which were normal. Hepatic encephalopathy improved in all patients in Group 1 and in one of three patients in Group 2 following the infusion. The ratio (see article) showed an excellent correlation with a grade of encephalopathy. When this ratio, previously 1.0 in the presence of encephalopathy, returned to the normal value near 3.0 to 3.5, encephalopathy improved. An excellent correlation was obtained between the ratio and the grade of encephalopathy and was dose related as well. The results suggest that different amino acid patterns in hepatic encephalopathy of differing etiologies require treatment modalities which may differ for the two types of encephalopathy. Whereas amino acid infusion appears to be a valuable, efficacious way of providing nutrition in treating hepatic encephalopathy in patients with cirrhosis and acute deterioration and coma, other means of therapy such as plasms "laundering" appear to be necessary in patients with fulminant hepatitis.

Adult↗