Biomedical subjects

M R Brinker

Publications and source records attributed to M R Brinker.

At least 37 records · Page 2Linked to original sources

PubMed1997

Blood flow to the immature hip. Ultrasonic measurements in pigs.

We quantitatively analyzed blood flow through the major arteries supplying the pig's femoral head during various hip positions and following ligation of various vessels in order to identify the vascular abnormalities which may be responsible for the development of avascular necrosis during the treatment of developmental dysplasia of the hip. Our findings reveal that a decrease in total blood flow to the femoral head occurs when the hip is held in the frog leg position with ligation of the deep femoral artery and proximal ligation of the lateral femoral circumflex artery, and ligation of the deep femoral artery, together with the lateral femoral circumflex artery proximally. In contrast, neither distal ligation of the medial femoral circumflex artery nor lateral femoral circumflex artery alone nor holding the hip in the Lange position caused a statistically significant decrease in total flow. We also observed a unique steal effect on total proximal femoral blood flow, with the hip held in the frog leg position. In 4 of 7 pigs, we found a reversal of flow in the medial femoral circumflex artery.

Animals↗

PubMed1997

Comparison of general and epidural anesthesia in patients undergoing primary unilateral THR.

One hundred ninety-five consecutive patients underwent 195 primary unilateral total hip arthroplasties between January 1988 and December 1993. Patients were divided into three groups based on the type of anesthesia utilized for their procedure. Group I consisted of 108 patients (59 women and 49 men; average age 56 years) who had general endotracheal anesthesia alone. Group II consisted of 70 patients (41 women and 29 men, average age 58 years) who had general endotracheal anesthesia with epidural augmentation intraoperatively and postoperatively. Group III consisted of 17 patients (6 women and 11 men, average age 62 years) who had epidural anesthesia only. Data were analyzed by anesthesia group to compare a variety of clinically relevant factors. No statistically significant differences among groups were noted regarding average age at surgery, the underlying diagnoses leading to joint replacement, the number of preexisting medical conditions, length of hospitalization, nonsurgical operating room time, intraoperative blood transfusions, intraoperative femur fractures, deep venous thrombosis, deep infections, death, or the prevalence of postoperative urinary tract infections. Postoperative urinary tract infections correlated with duration of Foley catheterization, but not the duration of epidural catheterization. Significant differences among anesthesia groups were observed for two factors: 1) estimated intraoperative blood loss was highest for Group I (P < .05) and was primarily a function of surgical time (P < .0001), and 2) postoperative Hemovac output (over the first and second postoperative 24-hour periods) was greatest for Group II (P < .05). Epidural anesthesia appears to be a safe modality in patients undergoing primary unilateral total hip replacement.

Adult↗

PubMed1997

A new in vivo method for the direct measurement of nutrient artery blood flow.

A new method of directly measuring nutrient artery blood flow using ultrasonic probes is described. These probes have provided reproducible results in our experiments. Advantages of ultrasonic probes include the direct measurement of blood flow through small arteries, ease of use, accuracy of measurement, applicability to a wide range of vessel diameters, the capability of chronically monitoring blood flow over time using permanently implanted probes, and the ability to use the method in conjunction with previous methods of bone blood flow measurement. The method is limited to the extent that only the contribution of the nutrient artery can be measured and total bone blood flow cannot be assessed. Tibial nutrient arterial flow and cardiac output were measured in adult mongrel dogs. Two experiments were performed: 1) bilateral baseline tibial nutrient artery blood flow measurements over time and 2) tibial nutrient blood flow comparing inhaled anesthesia (halothane/nitrous oxide/oxygen) and intravenous anesthesia (pentobarbital [Nembutal]). In 15 mongrel dogs, tibial nutrient artery blood flow averaged 1.46 +/- 0.72 mL/min (0.09 +/- 0.05 percent of cardiac output and 2.75 +/- 1.95 mL/min/100 g of bone). No significant difference in tibial nutrient artery blood flow was observed between animals given intravenous and inhaled anesthesia (P > .05). As a basic research tool, transit-time ultrasonic blood flow technology may be useful. The method is relatively easy to use and may be applied to experimental models designed to investigate various physiologic and pathologic states frequently encountered in orthopedics (eg, shock, sepsis, fractures).

Adjuvants, Anesthesia↗

PubMed1997

An analysis of the actual cost of tibial nonunions.

The financial and medical records of 11 patients diagnosed with a tibial nonunion were evaluated in order to assess the costs associated with the care of this clinical entity. The initial tibia fractures were seen at Hermann Hospital (Houston, Texas) between April 1991 and June 1993. We included only those patients who had a diagnosis of tibial shaft nonunion which we defined as a tibial fracture which was without radiographic or clinical evidence of progressive healing 6 months after the initial injury. A total of 9 patients were available for evaluation and 2 were lost to follow-up.

Adolescent↗

PubMed1997

Alcohol and drug use in adult patients with musculoskeletal injuries.

This study reviewed trauma registry data for information on the prevalence of alcohol and drug use in adult patients with fractures and dislocations admitted to Hermann Hospital, Houston, Texas, from January 1992 to December 1994. Of the 1776 adult patients aged 18 years or older, 1126 (63%) were tested for blood alcohol concentration, and 873 (49%) had their urine screened for a panel of 58 drugs. Of the patients tested, 467 (41%) had positive blood alcohol concentrations, and 335 (30%) were legally intoxicated (blood alcohol concentration > or = 0.10%). Of the patients providing urine specimens, 191 (22%) had samples that were positive for one or more drugs. Overall, 9% of the patients tested were positive for both alcohol and drugs, and 54% were positive for either alcohol or drugs. The highest prevalence of alcohol use was in patients aged 21 to 33 years, and men were intoxicated more often than women. Alcohol use was more commonly associated with motor vehicle accidents, pedestrian or bicycle accidents, and gunshot wounds; intoxification was associated with a higher incidence of tibia fractures. The average injury severity score was higher, the duration of stay was longer, and total hospital charges were higher for the alcohol-positive group. Patients testing positive for alcohol or drugs were more likely to lack insurance coverage.

Accidents↗

PubMed1996

Primary noncemented total hip arthroplasty in patients with ankylosing spondylitis. Clinical and radiographic results at an average follow-up period of 6 years.

Twenty consecutive primary noncemented total hip arthroplasties performed on 12 men with ankylosing spondylitis were available to be studied clinically and radiographically at an average follow-up period of 75 months (range, 27-121 months). The average patient age at the time of surgery was 35 years (range, 23-53 years). Harris hip scores averaged 48.4 before surgery and 89.1 at the most recent follow-up examination. Significant improvements in pain, function, and range of motion were observed following total hip arthroplasty. No hip has required a surgical revision or reoperation. Heterotopic ossification was observed in 6 of 14 hips (43%) in the ankylosing spondylitis patients who had not had any perioperative prophylaxis for heterotopic bone formation. By contrast, 43 of 49 hips (88%) demonstrated heterotopic bone formation in a well-defined control group of 45 men with other diagnoses undergoing the same procedure by the same group of surgeons at the same institution. During the same period using the same implants. A thorough review of the literature and data from the institution does not support the notion that ankylosing spondylitis patients are necessarily predisposed to form heterotopic ossification. The use of routine perioperative prophylaxis for heterotopic ossification may not be warranted in all patients with ankylosing spondylitis undergoing routine primary noncemented total hip arthroplasty.

Adult↗

PubMed1996

Demographic biases found in scoring instruments of total hip arthroplasty.

Four hip scoring systems were used in evaluating 200 adult subjects who had no prior history of injury, pathologic condition, or treatment of the hips, knees, lower extremities, or spine. All subjects were in the age range typical of a total hip arthroplasty candidate (average age, 65 years; range, 50-100 years). In addition to a physical examination, complete demographic data were collected on each subject. Data were recorded on standardized flow sheets so that hip scores could be calculated; scores were normalized by dividing the observed scores by the maximum possible score. The average normalized total hip scores were Harris hip score, 90.8%; modified Harris hip score, 91.9%; Merle D'Aubigne score, 93.9%; and Hospital for Special Surgery hip rating 87.5%. Demographic variables that had a significant negative correlation with hip scores included advanced age (particularly past age 85), an income below the poverty level, and the presence of two or more major medical conditions. Differences in hip scores between different study groups that have not been matched for various clinically relevant factors ("case mix") are at least as likely to represent differences in the patient populations as differences in surgical technique or implant design. Hip scores may decline over the course of a 10- to 20-year follow-up period due to the change in a patient's age and/or medical condition rather than any factor relating to the hip arthroplasty.

Age Factors↗

PubMed1996

In-hospital charges associated with the treatment of adult femoral neck fractures.

A retrospective analysis of 41 adult patients treated for a femoral neck fracture was performed to determine the variables that best predict total hospital charges. The patients were treated for an isolated femoral neck fracture at our hospital from January 1993 through December 1994. There were 13 men and 28 women. The average age at the time of injury was 63 years. The average length of stay was 12.1 days, and the average total hospital charges per patient were $16,072. No physician fees were included in our analysis. Detailed multivariate regression analysis of 10 variables was performed for each patient. Stepwise linear regression analysis, which controlled for all variable (such as age at injury, number of medical illnesses, gender, and others), revealed that the strongest predictors of total hospital charges were the number of medical illnesses (P < 0.0001), age at injury (P = 0.023), length of stay (P < 0.0001), and number of complications (P = 0.0007).

Adult↗

PubMed1995

The orthopaedic manifestations of prune-belly (Eagle-Barrett) syndrome.

Forty children were managed for prune-belly syndrome between 1979 and 1989, and twenty-five of them had musculoskeletal abnormalities. The musculoskeletal abnormalities were primary in twenty-two children, secondary to renal osteodystrophy in one, and both primary and secondary to renal osteodystrophy in two. Thirteen children had marked abnormality of the hip, and congenital dislocation was typically resistant to conventional treatment. Scoliosis was seen in seven patients. Pectus excavatum (a chest-wall deformity) was seen in eleven patients, including five of the six who had an idiopathic-like curve. Although prune-belly syndrome is uncommon, the diagnosis necessitates a thorough orthopaedic evaluation because of the high prevalence of associated musculoskeletal abnormalities.

Child↗

PubMed1995

Posterior fracture-dislocation of the hip in a jogger.

Posterior fracture-dislocation of the hip is an uncommon athletic injury, occasionally seen in contact and high-energy sports. The mechanism of injury in this case highlights the high hip joint forces possible during running. The key treatment principle is early reduction of the hip joint, since the incidence of osteonecrosis of the femoral head and degenerative arthrosis increases with delay. Operative treatment will frequently be required to achieve a stable, congruent reduction of articular surfaces, essential for good long-term results. Partial weight-bearing exercise such as swimming and bicycling may aid rehabilitation. Long-term follow-up, with serial radiographs, is important to detect late complications.

Acetabulum↗

PubMed1995

Adjunct fibula strut bone graft in resurfacing hip arthroplasty.

Femoral neck fracture following surface replacement is a reported complication. Adjunct autogenous fibula strut bone grafting has been proposed as a means of reducing or eliminating this occurrence. This paper reports the long-term follow-up of two cases. One patient did well for 9 years prior to sustaining a traumatic femoral neck fracture while intoxicated; the second patient continues to do well 8.5 years postoperatively. While definite conclusions cannot be drawn, these two patients represent our longest-clinical successes using surface replacement arthroplasty.

Adult↗

PubMed1994

Primary total hip arthroplasty using noncemented porous-coated femoral components in patients with osteonecrosis of the femoral head.

Ninety consecutive total hip arthroplasties in 73 patients with osteonecrosis of the femoral head yielded 81 hips in 64 patients (37 men and 27 women) available for evaluation after a 4-8-year follow-up period. The average age at surgery was 39.9 years (range, 20-66 years). Osteonecrosis etiology was idiopathic in 13 hips, alcohol-induced in 15, femoral neck fracture in 12, and slipped capital femoral epiphysis in 2. The remaining 39 cases were related to steroids, which were administered for a variety of reasons. Two types of noncemented, porous-coated, straight-stem femoral components and three types of acetabular components were utilized. Good or excellent clinical results were recorded in 80.2% of the patients. Average Harris hip scores improved from 52.9 to 87.9 points. Nine patients required revision of at least one component and were significantly younger than those with unrevised components. A revision rate of 24.1% was recorded in patients under 35 years of age at the time of primary surgery. Good or excellent clinical results were seen in 92.3% of the idiopathic cases, 86.7% of the alcohol-induced cases, 77.8% of the renal transplant cases, and 62.5% of the systemic lupus erythematosus cases. The overall mortality rate at the follow-up evaluation was 14%; it was 50% in renal transplant patients. Analysis of the clinical results based on the implants showed no significant differences in Harris hip scores or pain and function scores. While total hip arthroplasty using noncemented porous-coated femoral stems appears to give better results than cemented procedures in patients with osteonecrosis of the femoral head, the results appear to be inferior to those reported in patients with other diagnoses.

Adult↗

PubMed1994

Myelomeningocele at the sacral level. Long-term outcomes in adults.

We reviewed the long-term outcome of thirty-six patients who had a myelomeningocele at the sacral level and whose average age was twenty-nine years (range, nineteen to fifty-one years). The patients were followed at our institution for an average of ten years (range, one to thirty-three years); however, the medical records from birth on were available for all of the patients. Instead of the expected outcome that function had been maintained in this group of patients, we found a decline in the ability to walk of eleven of the thirty-five patients who had been community ambulators initially. At the time of the most recent follow-up examination, five had become household ambulators, two were non-functional ambulators, and four were non-ambulators. The one patient who initially had been a household ambulator was a non-ambulator at the time of the most recent follow-up examination. A decrease in plantar flexion was found in fourteen patients and a decrease in plantar sensation, in fifteen. Breakdown of the skin and soft-tissue infections on the plantar surface of the metatarsal heads and of the heel were seen in twenty-seven and twenty-three patients, respectively, and were related to the absence of plantar sensation. Fifteen patients had osteomyelitis involving the lower extremity. Eleven patients had had a total of fourteen amputations: five involved one toe or more, four involved one ray or more, two were Syme amputations, and three were below-the-knee amputations. By the most recent follow-up examination, thirty-three patients had had a total of 371 orthopaedic procedures. The procedures included tendinous procedures; osteotomies; soft-tissue releases, transfers, and débridements; amputations; and arthrodeses of the lower extremities or spine.

Adult↗

PubMed1993

Moonlighting in a university surgical training program.

The impact of house officer moonlighting on training performance was assessed through a faculty questionnaire and house officer survey distributed in the Department of Surgery at Tulane University School of Medicine. Responses were obtained from 30 house officers and 15 faculty members. Most house officers who moonlighted did so one or two times each month; most were employed in emergency departments. Yearly earnings from moonlighting averaged approximately $10,000. Although many house officers were in debt from medical school, debt was not the primary reason for moonlighting. Many faculty members disapproved of moonlighting, but agreed to monitoring by clinical performance and American Board of Surgery In-Training Examination. A statistically significant relationship was found between yearly income from moonlighting and decreasing scores on the American Board of Surgery In-Training Examination.

Attitude of Health Personnel↗

PubMed1992

Neurologic testing with somatosensory evoked potentials in idiopathic scoliosis.

A study was undertaken to determine if a somatosensory conduction delay is present in the posterior columns of adolescents with idiopathic scoliosis. Somatosensory evoked potentials were recorded after median and posterior tibial nerve stimulation in 12 adolescent subjects being followed for idiopathic scoliosis with an average age of 14.6 years (range, 12.0-16.6 years). Twelve normal controls matched for age, sex, race, and height underwent identical testing. Evoked potential peak latencies were measured and conduction velocities calculated. Results showed no difference between scoliotics and normal controls. Comparable posterior column conduction velocities were recorded in both groups. If a defect in posterior column function does exist in adolescent idiopathic scoliosis, as previously postulated, it is not reflected by a conduction delay as measured by somatosensory evoked potential testing.

Adolescent↗

PubMed1991

Vertebral aneurysmal bone cyst. A case report and review.

The case of a 16-year-old boy with an aneurysmal bone cyst of the fourth lumbar vertebra and a herniated nucleus pulposus of the L4-5 disc is presented. Symptoms included progressive lower back pain and bilateral lower extremity weakness. Roentgenographic studies were consistent with a vertebral aneurysmal bone cyst with an expansile lesion that compromised the neural canal and an L4-5 herniated nucleus pulposus. Surgical treatment included tumor excision, L4-5 discectomy, lumbar decompression, and posterolateral and anterior lumbar fusion. Postoperatively, the lower back pain and lower extremity symptoms resolved. The patient continues to do well at 1-year follow-up.

Adolescent↗

PubMed1990

Performance of retrieved Kuntscher intramedullary rods: improved corrosion resistance with contemporary material design.

Eighteen Kuntscher-type intramedullary rods were obtained after human implantation periods ranging from 1 to 23 years. A clinical evaluation, metallurgical and chemical analyses of each implant were performed. Idiopathic, implant-related pain was the most common reason for removal, but was not related to extent of implant corrosion. When classified as early versus contemporary material compositions, a significant increase in surface corrosion, inclusion content and carbon content were demonstrated in rods made of the earlier composition of stainless steel. Intergranular corrosion was associated with structural design, rather than material microcleanliness or composition. While contemporary intramedullary fracture fixation provides excellent clinical results, the present investigation suggests that the performance of stainless steel implants may be improved through continued refinement of steel composition, careful consideration of structural design and fabrication techniques, and by routine removal of implants at the earliest opportunity.

Biocompatible Materials↗

PubMed1990

Factors important to students in selecting a residency program.

A 22-item questionnaire, designed to assess the factors students considered important when they ranked residency programs, was distributed to the 1988 senior class of Tulane University School of Medicine just before the submission deadline of the National Residency Matching Program. Completed surveys were obtained from 111 of the 157 graduating students (approximately 71%) and were representative of the entire class in terms of sex, age, race, marital status, and anticipated field of specialization. Results of this investigation suggest that the satisfaction of a program's house officers and the seniors' general impression at the interview were the most important selection factors of the matriculating seniors surveyed. Diversity of the training experience and geographic location were also important selection factors. House officer benefits and salary were low-priority factors in the seniors' program selections.

Career Choice↗