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Biomedical subjects

F Gottschalk

Publications and source records attributed to F Gottschalk.

At least 19 recordsLinked to original sources

Transfemoral amputation. Biomechanics and surgery.

The technique of transfemoral amputation has evolved during the last decade whereby muscle stabilization and biomechanical principles have gained new significance. Maintenance of the femoral shaft axis close to normal can be achieved by preservation of the adductor magnus and by myodesis of the muscle to the residual femur. By following established biomechanical principles, and satisfactory surgical techniques, patients undergoing transfemoral amputation are easier to fit with a prosthesis and more likely to remain able to ambulate. Reduction in stump problems can be achieved, and improvement in stump strength is seen.

Adult↗

The effects of twelve weeks of bed rest on bone histology, biochemical markers of bone turnover, and calcium homeostasis in eleven normal subjects.

This study was undertaken to examine the effects of 12 weeks of skeletal unloading on parameters of calcium homeostasis, calcitropic hormones, bone histology, and biochemical markers of bone turnover in 11 normal subjects (9 men, 2 women; 34 +/- 11 years of age). Following an ambulatory control evaluation, all subjects underwent 12 weeks of bed rest. An additional metabolic evaluation was performed after 12 days of reambulation. Bone mineral density declined at the spine (-2.9%, p = 0.092) and at the hip (-3.8%, p = 0.002 for the trochanter). Bed rest prompted a rapid, sustained, significant increase in urinary calcium and phosphorus as well as a significant increase in serum calcium. Urinary calcium increased from a pre-bed rest value of 5.3 mmol/day to values as high as 73 mmol/day during bed rest. Immunoreactive parathyroid hormone and serum 1,25-dihydroxyvitamin D declined significantly during bed rest, although the mean values remained within normal limits. Significant changes in bone histology included a suppression of osteoblastic surface for cancellous bone (3.1 +/- 1.3% to 1.9 +/- 1.5%, p = 0.0142) and increased bone resorption for both cancellous and cortical bone. Cortical eroded surface increased from 3.5 +/- 1.1% to 7.3 +/- 4.0% (p = 0.018) as did active osteoclastic surface (0.2 +/- 0.3% to 0.7 +/- 0.7%, p = 0.021). Cancellous eroded surface increased from 2.1 +/- 1.1% to 4.7 +/- 2.2% (p = 0.002), while mean active osteoclastic surface doubled (0.2 +/- 0.2% to 0.4 +/- 0.3%, p = 0.020). Serum biochemical markers of bone formation (osteocalcin, bone-specific alkaline phosphatase, and type I procollagen extension peptide) did not change significantly during bed rest. Urinary biochemical markers of bone resorption (hydroxyproline, deoxypyridinoline, and N-telopeptide of type I collagen) as well as a serum marker of bone resorption (type I collagen carboxytelopeptide) all demonstrated significant increases during bed rest which declined toward normal during reambulation. Thus, under the conditions of this study, the human skeleton appears to respond to unloading by a rapid and sustained increase in bone resorption and a more subtle decrease in bone formation.

Adult↗

Reflection ultrasound velocities and histomorphometric and connectivity analyses: correlations and effect of slow-release sodium fluoride.

To better understand how structural and functional bone properties contribute to the changes in bone biomechanical properties revealed by ultrasound critical angle reflectometry (UCR) analysis, we measured both UCR velocities and histomorphometric properties in bone biopsy specimens from 33 osteoporotic patients before and following intermittent slow-release sodium fluoride (SRNaF) and continuous calcium citrate administration. Mean skeletal fluoride exposure was 17 months, and mean skeletal fluoride content was 0.203 +/- 0.088 SD% bone ash. Intermittent SRNaF and continuous calcium citrate promoted significant increases in trabecular thickness (122 +/- 18 SD microm to 131 +/- 20, p = 0.020), mineral apposition rate (0.79 +/- 0.26 to 1.05 +/- 0.40 microm/day, p = 0.014), and a significant decline in eroded surface (3.9 +/- 1.6 to 2.8 +/- 1.4%, p = 0.002). There were also significant increases in node number (0.193 +/- 0.100 to 0.368 +/- 0.245, p < 0.01) and node-to-node strut length (0.076 +/- 0.087 to 0.191 +/- 0.173, p < 0.01) relative to total cancellous area. Cortical UCR velocity did not change but cancellous velocity significantly increased by 97 m/s following therapy (p = 0.0005). When compared against the significant changes in bone histomorphometry and connectivity, the sum of both cancellous and cortical ultrasound velocities was significantly correlated with node number/area (R2 = 0.305, p < 0.0001) and node-to-node strut length/area (R2 = 0.372, p < 0.0001) and to a lesser extent with mineral apposition rate (R2 = 0.106, p = 0.032). Multiple regression analysis demonstrated that 40% of the variance in the sum of the UCR velocities can be accounted for by the variability in these histomorphometric and connectivity parameters. There were no significant correlations between the sum of cortical and cancellous ultrasound velocities and cancellous bone volume (R2 = 0.014, p = 0533), trabecular thickness (R2 = 0.012, p = 0.47), or bone mineral density (R2 = 0.003, p = 0.80). These observations indicate that velocity measurements with the UCR methodology show an improvement in bone elasticity associated, in part, with an improvement in the rate of bone mineralization and an improvement in bone quality at the structural level as shown by microarchitecture.

Adult↗

Serum IGF 1 is low and correlated with osteoblastic surface in idiopathic osteoporosis.

We have previously reported that bone formation is impaired on histomorphometric analysis of bone in patients with idiopathic osteoporosis. In the present study, 30 patients with idiopathic osteoporosis (18 men and 12 women mean age 44 +/- 12 years) and spinal and/or appendicular fractures were studied. Compared with control values, bone biopsy analysis demonstrated reduced bone volume (13.0 +/- 4.4 vs. 23.2 +/- 4.4, p < 0.0001), osteoid volume (0.13 +/- 0.13 vs. 0.32 +/- 0.19, p = 0.001), osteoid surface (5.9 +/- 4.3 vs. 12.1 +/- 4.6, p = 0.0004), and diminished double-labeled mineralizing surface (MS/BS 2.0 +/- 2.1 vs. 5.1 +/- 2.7%, p = 0.0001) in the patients. Since insulin-like growth factor 1 (IGF-1) is one of the major determinants of bone growth and remodeling, we measured the circulating level of this growth factor in these patients. The mean serum IGF-1 concentration was lower in patients as compared with 33 healthy age-matched controls (193 +/- 59 SD ng/ml vs. 232 +/- 79). A significant difference was noted between the two groups only in subjects younger than 36 years. In patients with idiopathic osteoporosis, regression analysis of serum IGF-1 against the various histological parameters measured from the bone biopsy disclosed significant correlation's between serum IGF-1 and osteoblastic surface (r = 0.429, p = 0.032), mineralizing bone surface with a double label (r = 0.480, p = 0.015), and the bone formation rate (r = 0.457, p = 0.021). These findings suggest that in young eugonadal individuals with idiopathic osteoporosis, reduced IGF-1 concentrations may have an etiological role in the development of this disease.

Adult↗

Pre and post-amputation mobility of trans-tibial amputees: correlation to medical problems, age and mortality.

This retrospective study compares pre and post-amputation mobility and the influence of age and associated medical problems. Data from the charts of 120 male patients who underwent unilateral trans-tibial (below-knee) amputation at the Dallas Veteran's Administration Hospital between June, 1983 and October, 1991, were collected and analyzed. Mobility was assessed with a six level scale developed by Volpicelli et al. (1983). The presence of cardiac disease, pulmonary disease (COPD), peripheral vascular disease (PVD), diabetes mellitus, degenerative joint disease, blindness, cerebral vascular accident (CVA), and age are correlated with changes in mobility after amputation. Older patients had more medical problems and lower post-amputation scores Individual medical problems did not influence mobility scores, but the presence of COPD and PVD lowered pre-amputation mobility scores. Cardiac disease and diabetes mellitus influenced post-amputation mobility scores by lowering them, either together or individually. Regardless of age, however, patients with more medical problems were poor ambulators. The cause of amputation per se did not influence mobility scores.

Activities of Daily Living↗

Functional outcome of below-knee amputation in peripheral vascular insufficiency. A multicenter review.

A retrospective functional outcome study was performed on 299 patients treated with below-knee amputations for peripheral vascular disease during a three-year period in six Veterans Administration special amputee centers. Sixty-one percent of the patients were diabetic, and 25% were previously unilateral amputees. Surgery was performed with a long posterior flap in 92.3%, sagittal flaps in 20%, and guillotine open technique in 5.7%. Wound management was accomplished with rigid plaster dressings in 75.3%, pneumatic compression dressing in 14%, and soft dressings in 10.7%. At follow-up evaluation one to two years later, 36.1% had died. Thirteen percent suffered wound complications, with 6.7% requiring revision to a more proximal amputation level. Eighty-seven percent of community ambulators maintained their ambulatory status. A comparable percentage maintained their ability to walk with a prosthesis.

Amputation, Surgical↗

Impaired bone formation in male idiopathic osteoporosis: further reduction in the presence of concomitant hypercalciuria.

We present iliac bone histomorphometric data and related biochemical data from 16 nonalcoholic men (50 +/- 11 (SD) years) referred for evaluation of spontaneous skeletal and/or appendicular fractures and reduced spinal bone density. All men were eugonadal and had no known underlying disorder associated with osteopenia. For the group, mean serum chemistry values were within normal limits including immunoreactive parathyroid hormone, osteocalcin and serum 1,25-dihydroxyvitamin D [1,25(OH)2D]. Nine men demonstrated hypercalciuria (greater than or equal to 0.1 mmol/kg per day) while on a constant metabolic diet of 20 mmol/day Ca. Their 24-hour urinary calcium was significantly greater than that for the remaining 7 men (7.4 +/- 1.6 vs. 5.0 +/- 0.8 mmol/day, p = 0.003), as was their calciuric response to a 1 g oral calcium load (0.23 +/- 0.06 vs. 0.15 +/- 0.05 Ca/creatinine, p = 0.042). Serum parameters (including parathyroid hormone and 1,25(OH)2D) of hypercalciuric and normocalciuric men were not significantly different. Histomorphometric indices for cancellous bone demonstrated significant differences between the entire group of osteoporotic men and age-adjusted normal values for bone volume (11.4 +/- 4.0% vs. 23.2 +/- 4.4%), osteoid surface (5.6 +/- 3.9% vs. 12.1 +/- 4.6%), osteoblastic surface (2.0 +/- 2.3% vs. 3.9 +/- 1.9%), and mineralizing surface (1.9 +/- 2.4% vs. 5.1 +/- 2.7%); there were also significant differences in bone formation rate (total surface referent) (0.004 +/- 0.001 vs. 0.011 +/- 0.006 mm3/mm2 per year). Compared with the normocalciuric group the 9 hypercalciuric men had significantly lower osteoblastic surfaces (1.6 +/- 1.9% vs. 2.5 +/- 2.6%) and mineralizing surfaces (1.4 +/- 1.5% vs. 2.7 +/- 3.2%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Lack of deleterious effect of slow-release sodium fluoride treatment on cortical bone histology and quality in osteoporotic patients.

We evaluated the effects of intermittent slow-release sodium fluoride (SRNaF) and continuous calcium citrate therapy on cortical bone histology, reflection ultrasound velocity (material strength) and back-scattered electron image analysis (BEI) in 26 osteoporotic patients before and following therapy. All measurements were made on transiliac crest bone biopsies obtained before and following 2 years of therapy in each patient. For all 26 patients there were no significant changes in cortical bone histomorphometric parameters. In 15 patients in whom bone material quality was assessed by reflection ultrasound, there was no change in velocity (4000 +/- 227 SD to 4013 +/- 240 m/s). BEI disclosed no mineralization defects or the presence of woven bone. Mean atomic number (density) of bone increased slightly, but significantly (9.261 +/- 0.311 to 9.457 +/- 0.223, P = 0.031). While these changes are less marked than those observed for cancellous bone, they indicate that this form of therapy does not adversely affect cortical bone remodelling.

Adult↗

Assessment by reflection ultrasound method of the effect of intermittent slow-release sodium fluoride-calcium citrate therapy on material strength of bone.

It has been suggested that fluoride therapy, while increasing bone mass, produces bone with inferior mechanical properties. In the present report this hypothesis was tested using a novel reflection ultrasound technique. Transiliac crest bone biopsies were obtained from 16 patients with osteoporosis and vertebral compression fractures (12 women and 4 men, mean age 56 years) before and after approximately 2 years of intermittent slow-release sodium fluoride therapy (25 mg twice a day) combined with continuous calcium citrate supplementation. Samples were analyzed by a reflection ultrasound method, which analyzes ultrasound velocity with a sample site resolution of 200 microns and thus provides a measure of the mechanical property of single trabeculae (material). For the group, mean fractional change in velocity increased 6.1 +/- 2.3% (SEM) from a mean value of 3303 +/- 80 to 3484 +/- 55 m/s (p = 0.028). A total of 13 patients (81%) demonstrated higher velocities after treatment. Thus reflection ultrasound analysis of bone appears to provide a sensitive means of assessing changes in the material property of bone. Furthermore, these results suggest that the treatment regimen utilized in these patients improves strength of bone at the material or trabecular level largely independently of change in bone mass. The combination therapy also increased spinal (L2-L4) bone density for the group as assessed by dual-photon absorptiometry (5.3 +/- 2.0%). There was no significant correlation between the change in ultrasound velocity and bone density (r = 0.0026, p = 0.996).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Hip disarticulation. An 11-year experience.

Thirty-eight hip disarticulations performed in 34 patients were retrospectively reviewed. The indications were ischemia secondary to atherosclerosis in 17 cases, femoral osteomyelitis in 10, and trauma in 11. Patient ages ranged from 20 to 95 years. The mortality was 60% in patients with ischemia with preoperative infection, 20% in patients with ischemia without preoperative infection, 22% in patients with femoral osteomyelitis, 100% in patients with trauma with preoperative infection, and 33% in patients with trauma without preoperative infection. The overall mortality was 44%. Postoperative wound infections were frequent (63%) and had poor correlation with the presence of a preoperative wound infection. No patient was able to use a prosthesis after hip disarticulation, but most were independent in wheelchairs.

Activities of Daily Living↗

Fluoride rapidly and transiently raises intracellular calcium in human osteoblasts.

We examined the effect of fluoride (F) on intracellular ionic calcium [Ca2+]i in normal human osteoblasts maintained in culture. Cells were grown on glass coverslips to near-confluency and loaded with the Ca-sensitive dye, fura-2AM. Fluorescence changes were monitored in single cells using an inverted microscope coupled by fiberoptic to a microspectrofluorometer. The addition of F (100 ng/mL) to the medium promoted a rapid and significant increase in free [Ca2+]i from a resting level of 245 +/- 36 SE nM to a peak concentration of 440 +/- 51 nM (p less than 0.04). This increase in [Ca2+]i began at 10-20 s after addition of F and was maximal by 30 s. Intracellular [Ca2+]i levels then returned to near resting values by 60-80 s after F addition. This response was evident with as little as 25 ng/ml of fluoride and was dose dependent up to 500 ng/ml. At concentrations greater than 500 ng/ml, there appeared to be an attenuation of the rise in [Ca2+]i. The observed rise in [Ca2+]i was dependent on extracellular calcium since lowering extracellular calcium concentration or incubation with calcium channel blockers abolished the response. This observation supports a role of increased [Ca2+]i as one of the initial events of fluoride on action osteoblasts.

Benzofurans↗

The Syme amputation: success in elderly diabetic patients with palpable ankle pulses.

The Syme amputation is an old operation that has been used during this century primarily as a means of treating traumatic injuries to the forefoot in military patients. In 1984 we made a deliberate attempt to perform the operation in a highly selective group of dysvascular patients with forefoot necrosis who happened to have a palpable posterior tibial pulse. We reviewed the charts of 26 patients who underwent a one-stage (3 patients) or two-stage (23 patients) Syme amputation. The mean age was 60 years, (range 32 to 74 years). There were 17 insulin-dependent diabetic patients, and 3 diet-controlled diabetic patients. Twenty-two patients (85%) had a palpable posterior tibial pulse before surgery. Fourteen patients (54%) underwent a preliminary Ray (4) or transmetatarsal (10) amputation to rid the forefoot of an active infection. Overall, 20 patients (77%) had successful Syme amputations. Nineteen of 22 patients (85%) with a palpable posterior tibial pulse had a successful amputation in contrast to one out of four patients (25%) who did not have a palpable pulse before surgery (p = 0.04). The mean follow-up of all patients was 23 months. The durability of the operation was demonstrated in finding that only one patient in 20 initially successful Syme amputations required revision to the below-knee level. The two-stage Syme amputation can be a very gratifying operation with success rates approaching 85%, even if offered to elderly diabetic patients. The single most important feature for success is to limit the operation to those patients with a palpable posterior tibial pulse before operation.

Amputation, Surgical↗

Indications and results of intertrochanteric osteotomy in osteonecrosis of the femoral head.

The intertrochanteric osteotomy has been used for several years as a method of treatment of osteonecrosis of the femoral head. As the clinical experience has increased, it has become apparent that, if the procedure is to succeed, specific criteria have to be met. In general, a valgus/flexion osteotomy should be done in patients younger than 40 years who have a Ficat Stage II and/or crescent sign. A necrosis angle of less than 200 degrees as measured on anteroposterior and lateral roentgenograms is also important in predicting a successful outcome. Caudal oblique roentgenograms also help determine the status of the posterior femoral head and whether the osteotomy is feasible. Preoperative planning is important to reduce operating time and obtain a good end result. A 95 degrees blade-plate is used, and if necessary, a small wedge is excised to ensure coaptation of the osteotomy segments. The results of the procedure in 17 patients show that eight patients have a satisfactory result at a mean of three years, while three patients continue to have problems. Five patients have been converted to total hip arthroplasties, and one has a girdlestone arthroplasty. The unsuccessful results occurred in patients who were on corticosteroids or had continued metabolic bone abnormalities. Present experience confirms reports of other series. The operation should be offered only to the small group of patients with idiopathic, posttraumatic, or alcohol-induced osteonecrosis of the femoral head.

Adult↗

The functional anatomy of tensor fasciae latae and gluteus medius and minimus.

The more accurate description of the anatomy of the glutei and the new biomechanical theory that has been presented describe the abductor mechanism as a system in which the tensor fasciae latae has the primary function of balancing the weight of the body and the non-weight-bearing leg during walking. Gluteus medius with its three parts and phasic functions is responsible for the stabilisation of the hip joint in the initial phase of the gait cycle. It is important also in initiating the major gait determinant of pelvic rotation. Gluteus minimus functions as a primary hip stabiliser during the mid- and late phase of the gait cycle.

Biomechanical Phenomena↗

[Rupture of the fibular ligament of the upper ankle joint].

A prospective randomized trial was performed to compare conservative functional treatment and operative functional treatment for rupture of the lateral ankle ligament. On the basis of the results observed 1 and 2 years after injury, primary functional therapy with a orthetic support appeared to be the method of choice. In a 100-point clinical check-up scale we were not able to find any statistical differences between the treatments. This type of conservative treatment gives a high degree of mechanical stability, a shorter time off work and the ability to take a full, active part in sports within 3 months in all cases. Operative treatment is indicated only in cases of dislocation of the foot and ankle, ankle ligament rupture with additional osteochondral talus fracture, and second-stage injuries or reruptures.

Adult↗

Aneurysmal bone cyst of the calcaneus.

Aneurysmal bone cyst of the calcaneus is an uncommon entity. Radiographs showed a large lytic expanding lesion arising in the calcaneus with cortical disruption inferiorly. CT of the patient with this condition showed fluid-fluid levels that were the result of blood layering. These findings may suggest the specific diagnosis.

Adolescent↗