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Biomedical subjects

M Asher

Publications and source records attributed to M Asher.

At least 19 recordsLinked to original sources
PubMed2000

Treatment of selected neuromuscular patients with posterior instrumentation and arthrodesis ending with lumbar pedicle screw anchorage.

STUDY DESIGN: This is a retrospective analysis of 23 patients with severe neuromuscular spinal deformity treated with posterior instrumentation and fusion ending in the lumbar spine. OBJECTIVES: The purposes of this study were to determine the safety and efficacy of stopping posterior instrumentation constructs in the lumbar spine with pedicle screw anchorage. SUMMARY OF BACKGROUND DATA: There are sparse data in the peer-reviewed literature regarding indications and outcomes in patients with neuromuscular disorders for instrumented fusion ended short of the pelvis with transpedicular fixation. METHODS: The average age of patients at surgery was 18.4 years (range, 10-61 years). Additional anterior discectomy and fusion were performed in four patients with large, stiff curves. No patient received anterior instrumentation. Criteria for exclusion of the pelvis from the fusion were less than 15 degrees of pelvic obliquity as a result of a compensatory curve below the major curve(s), the absence of problematic lower extremity contractures, and, often, the potential for ambulation. Process and clinical outcomes and complications were analyzed. RESULTS: Radiographic follow-up was available in 21 patients at an average of 62 months (range, 24-110 months) after surgery. Their average Cobb angle was 71 degrees before surgery, 25 degrees after surgery (64% correction), and 32 degrees at follow-up (54% correction). Their average spinal-pelvic obliquity was 6 degrees before surgery, 5 degrees after surgery, and 6 degrees at follow-up. The average lower instrumented vertebra was lumbar 3.7. Clinical follow-up was available for all 23 patients for an average of 61 months (range, 24-110 months). There were no perioperative deaths, deep wound infections, pseudarthroses, or instrument failures. Outcomes based on responses to questionnaires completed by patient, parent, or caregiver were highly satisfactory in 20 patients (87%), satisfactory in 2 patients (9%) and neither satisfactory nor unsatisfactory in 1 patient (4%). CONCLUSION: Posterior instrumentation and arthrodesis using lumbar lower instrumented vertebra pedicle screw anchorage can be performed safely and effectively, in selected patients patients with scoliosis and minimal pelvic obliquity.

Adolescent↗
PubMed2000

Reoperation after primary posterior instrumentation and fusion for idiopathic scoliosis. Toward defining late operative site pain of unknown cause.

STUDY DESIGN: Retrospective case series. OBJECTIVES: To determine the frequency and categorize the indications for reoperation in three implant systems (Harrington, Cotrel-Dubousset [C-D], and Isola). To define late operative site pain (LOSP) of no apparent cause as an indication for implant removal and determine the success of implant removal in relieving LOSP. SUMMARY OF BACKGROUND DATA: Late operative site pain of no apparent cause has been discussed briefly in the literature but has not been investigated as a major indication for implant removal. METHODS: One hundred eighty-two of 190 consecutive patients with idiopathic scoliosis (96%) who underwent primary surgery between January 1, 1981, and December 31, 1992, by one surgeon in one hospital, with use of Harrington, C-D, or Isola instrumentation were studied an average of 9 years after surgery to determine the indications for and frequency of reoperation. RESULTS: The overall frequency of reoperation for all instrumentation types combined was 19%: Harrington, 19%; C-D, 24%; and Isola, 14%. By 6 years' follow-up the cumulative risk of reoperation by Kaplan-Meier analysis was Harrington, 14%; C-D, 21%; and Isola, 14%. (statistically nonsignificant difference). The most frequent indication for reoperation was LOSP of no apparent cause: 8% (14 patients) for all instrumentation types combined. The average interval between the initial operation and reoperation for LOSP was 46 months (range, 20-97 months). The frequency of each implant type was Harrington, 6%; C-D, 12%; and Isola, 6%. By 6 years' follow-up, the cumulative Kaplan-Meier risk for reoperation due to LOSP was Harrington, 5%; C-D, 13%; and Isola, 8% (statistically non-significant difference). Of the 14 patients who had instrumentation removal for LOSP, 10 (71%) had successful relief of pain after implant removal. CONCLUSIONS: Occurring regardless of implant type, LOSP of no apparent cause after posterior instrumentation of scoliosis is a distinct clinical entity and is relieved by implant removal in most patients.

Adolescent↗
PubMed1998

Treatment of hip dysplasia in older children with a combined one-stage procedure.

This retrospective study was conducted to determine the efficacy and complication rates associated with treating children of ambulatory age with idiopathic developmental dysplasia of the hip with open reduction and combined femoral and pelvic osteotomies. Eighteen hips were reviewed in 13 patients. The average patient age at surgery was 29 months (range, 15-117 months), with an average followup of 43 months (range, 24-78 months). Preoperative Tonnis classification identified six Class II, seven Class III, and five Class IV hips. Followup Severin classification identified 16 Class 1A and two Class 2A hips. The average center edge angle on most recent followup was 47 degrees (range, 25 degrees-70 degrees), and the acetabular index was 5 degrees (range, 0 degree-20 degrees). Avascular necrosis developed in one (5.5%) patient. Clinically, all patients were pain free with ambulation and had excellent results by McKay criteria. No patient required a second surgical procedure for recurrent subluxation or persistent acetabular dysplasia. The treatment of children who are of ambulatory age with developmental dysplasia of the hip using open reduction and combined osteotomies was safe and effective.

Child↗
PubMed1998

[Morphometric characteristics of the scoliotic spine].

GOAL: Results from a morphometric investigation performed on a rare complete scoliotic specimen are presented. The aim of the study is to describe the vertebral body wedging. MATERIALS: The specimen used in the study presented a thoracic curve of 150 degrees Cobb angle with the apex at T8. The measures were made using 3D-computer graphics models. The wedging in the frontal and sagittal planes as well as the 3D wedging were measured. The height variation of the vertebral bodies was also measured. RESULTS: The wedging measures show that it increases progressively with the vertebral level to reach a maximum of 27 degrees at the apex. Perdriolle has found a linear relation between the vertebral body wedging and the Cobb angle. The relation predicts a wedging of 24 degrees for 150 degrees of Cobb angle. An inflection point was identified on the vertebral end plate on the convex side. These inflection points were described by Perdriolle as being on the concave side of the vertebra. CONCLUSION: Our measures follow the relation between the Cobb angle and the wedging of the vertebral body, even for very large Cobb angles. Furthermore, inflection points on the vertebral body were identified on the convex side as opposed to the concave side in the literature. This leads us to believe that the vertebral body wedging progressively affects the vertebral endplates.

Adult↗
PubMed1997

Osteogenic protein-1 downregulates endothelin A receptors in primary rat osteoblasts.

Osteogenesis is a complex process whereby growth factors and mediators from both local and systemic sources modulate the bone-forming activities of osteoblasts. In the present study we utilized primary cultures of fetal rat calvarial cells to characterize osteoblast responsiveness to the vascular mediator endothelin-1 (ET-1) and to investigate whether ET-1 responses are regulated by osteogenic protein-1 (OP-1). We found that a 1- to 2-day exposure to OP-1 diminished ET-1 receptor ligand binding and signal transduction by downregulating ET-1 receptor mRNA expression. ET-1-mediated calcium signaling and ligand binding were completely abolished by the ETA receptor antagonist BQ-123, suggesting that ET-1 effects are mediated by this receptor. Northern analysis of total RNA revealed that ETA mRNA expression was inhibited approximately 50% by OP-1 treatment, whereas ETB receptor mRNA was not detected by this method of analysis. In OP-1-treated cultures, the magnitude and duration of ET-1 calcium signals varied among individual cells. This finding may be related to a heterogeneous OP-1 response, indicated by alkaline phosphatase induction in only a subpopulation of cells. These results suggest that modulation of osteoblast function by ET-1 occurs during distinct periods of phenotypic development and imply that downregulation of ET-1 responsiveness may be necessary for optimal bone formation in vivo.

Alkaline Phosphatase↗
PubMed1995

Current nursing practices in fever management.

Data regarding fever management were obtained through a retrospective or concurrent review of the medical records of 150 patients. For 41% of the patients studied, nurses notified physicians of the fever episode. The decision to treat fever was significantly influenced by fever intensity and the drawing of blood cultures, but not by age, length of hospital stay, or the duration of the fever episode. Despite recent evidence of the protective value of fever, the majority of fever episodes were treated. Acetaminophen alone, and acetaminophen in combination with physical cooling methods, were effective in lowering fever.

Adult↗
PubMed1989

The current status of scoliosis screening in North America, 1986. Results of a survey by mailed questionnaire.

In May, 1986, 374 questionnaires on the multiple aspects of school screening for scoliosis were mailed to health care professionals throughout North America. An overall response rate of 73% provided objective information about screening efforts. Results showed that although there is great variability among the programs, at least some screening is done in each of the 50 United States and the District of Columbia. Previously widespread in Canada, only two Provinces currently are officially engaged in screening, Alberta (research projects only) and Prince Edward Island. The most common target population seems to be grades five through nine for both boys and girls. Lack of funding appears to be the largest factor hampering data collection. Although many varied comments and suggestions were received, most called for: 1) new recommendations for screening boys and girls at different grade levels; 2) quantitative referral criteria; 3) improved data gathering: 4) statewide uniformity within programs; and 5) improved understanding within the medical community about indications for referral and the principles of scoliosis treatment.

Adolescent↗
PubMed1988

Comparison of intravenous nitroprusside, nitroprusside-captopril, and nitroglycerin for deliberate hypotension during posterior spine fusion in adults.

Three techniques for deliberate hypotension (mean arterial pressure, 60 to 70 mmHg) were prospectively compared in adults undergoing posterior spine fusion. Patients received either IV sodium nitroprusside, sodium nitroprusside with oral captopril pretreatment, or IV nitroglycerin. Patient groups were comparable in age, sex, weight, baseline hemodynamic and laboratory parameters, duration of surgery, and duration of hypotension. Absolute blood loss was significantly less in the group receiving nitroglycerin; however, there were no differences between groups when corrected for operative exposure (milliliter per spine segment exposed). Nitroprusside was effective in producing target blood pressure in all patients. Nitroglycerin was ineffective in two patients and two other patients required greater than 20 micrograms/kg/min. Both groups receiving nitroprusside developed significant postinfusion increases in arterial pressure. Blood pressure fell significantly after induction of anesthesia in patients receiving captopril. Cardiac index, heart rate, pulmonary capillary wedge pressure, intrapulmonary shunt, and arterial blood gases were comparable and did not change significantly in any group. Systemic vascular resistance fell during infusion in all groups and remained depressed after infusion in patients receiving nitroglycerin. Plasma renin activity was significantly increased in the group receiving captopril due to loss of feedback inhibition of renin release and rose significantly during infusion in those patients receiving nitroprusside alone. There were no complications. Nitroprusside with and without captopril pretreatment was associated with postoperative increases in arterial pressure, although not to hypertensive levels, probably due to loss of captopril activity after single-dose administration. The use of nitroglycerin was limited by lack of potency. There was no demonstrable clinical advantage for any of the three techniques.

Administration, Oral↗
PubMed1988

A modular spinal rod linkage system to provide rotational stability.

The effect of cross linkage on the in vitro stability of paired Harrington distraction rods was studied in an unstable fracture model using calf spine segments. Cross linkage used in conjunction with sublaminar wires significantly improved torsional stability, improved lateral bending stability, and had no adverse affect on stability for axial, forward flexion, or extension loading compared to rods alone, rods with bridges, and wired rods.

Equipment Design↗
PubMed1983

Factors affecting the ambulatory status of patients with spina bifida cystica.

Sixteen different factors that might affect the ambulatory status of patients with myelodysplasia after the age of five years were analyzed in ninety-eight patients using a linear regression technique (the Pearson correlation coefficient). Included in the study were fifty male and forty-eight female patients; the average age was fourteen years and four months (range, five years and nine months to thirty-one years and ten months). The sacral and fifth-lumbar paraplegics, with one exception, were all community ambulators. Fourth-lumbar paraplegics were usually functional ambulators, whose ability to walk was significantly influenced by musculoskeletal deformity of the spine, pelvis, hips, knees, feet, and ankles. Third-lumbar, first and second-lumbar, and thoracic level paraplegics usually were not functional ambulators. Ambulatory function was significantly influenced in third-lumbar paraplegics by hip deformity, in first and second-lumbar paraplegics by obesity and possibly by age, and in thoracic level paraplegics by age and by knee-foot-ankle deformities. Transitions in ambulatory status were usually to a lower functional level and were related to motivation, obesity, and musculoskeletal deformity. Ultimately, ambulatory status is probably related in large measure to the energy expenditure that is necessary to walk, but studies of energy requirements were not done. These findings emphasize the importance of controlling obesity as well as any musculoskeletal deformities that will influence the patient's ultimate walking ability.

Adolescent↗