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Biomedical subjects

L A Koman

Publications and source records attributed to L A Koman.

At least 19 recordsLinked to original sources
PubMed1992

Development of a new rabbit ear model for the longitudinal study of digital pathophysiology.

A rabbit ear model has been developed in which arterial pressure, auricular blood flow conductance, and microvascular perfusion can be followed continuously in conscious animals. Conductance is measured with a transit-time flow probe placed around the auricular artery, arterial pressure is measured with an abdominal aortic catheter, and cutaneous microvascular perfusion is assessed using laser Doppler fluxmetry. Placement of a femoral vein catheter permits administration of vasoactive substances. To date, rabbits have been instrumented for 90 days or longer. Auricular and abdominal arterial pressures were equal, permitting the calculation of auricular artery conductance. Microvascular perfusion as measured by laser Doppler fluxmetry followed changes in overall blood flow. The presence of postsynaptic alpha 2-receptors was confirmed by determining auricular conductance before and after the administration of intravenous alpha-agonists. The development of this unique model will help to advance the understanding of the pathophysiology of human digital thermoregulatory vascular abnormalities.

Albuterol↗
PubMed1992

Response of rabbit ear microvasculature to total body cooling as observed through a new implantable window.

A new implantable window was developed in order to study the native microcirculation of the rabbit ear. The responses of the ear microvasculature to total body cooling were studied before and after implantation of the window. No differences were found between arteriolar and venular vasoconstriction with cooling before and after implantation of the window. Arteriolar constriction was significantly greater than the venular response both before and after placement of the window (P = 0.014). Surface skin temperature of the instrumented and control ears was similar at room temperature (35.2 +/- 2.6 versus 36.1 +/- 1.0 degrees, respectively; P = 0.280); however, the instrumented ear was slightly warmer during cooling (17.9 +/- 1.9 versus 15.2 +/- 3.1 degrees; P = 0.024), suggesting increased blood flow in the instrumented ear. Details of construction and implantation of the window are described.

Animals↗
PubMed1992

Ligamentous injuries of the wrist in athletes.

The athlete's wrist is particularly prone to injury. Although many wrist injuries are dismissed as sprains or strains, a number of these injuries involve significant ligamentous damage that can lead to chronic carpal instability. A complete knowledge of the carpal ligamentous anatomy and classification of wrist instability patterns is necessary for the adequate diagnosis and treatment of these injuries.

Arthroscopy↗
PubMed1990

Quantitative analysis of cold stress performance after digital replantation.

Isolated cold stress testing (ICST) has been used to assess cold stress performance or digital thermoregulation, but statistical analysis of the results has been limited to visual comparisons of data. In this prospective study, 11 patients who underwent complete digital replantation were followed serially with ICST at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperatively, and the results were analyzed quantitatively. For that analysis, we devised a mathematical method that provided a cooling and a warming coefficient to fit the data. Differences in these cooling and warming coefficients were then regressed against time after replantation, patient age, number of digits replanted, hand dominance, and clinical evidence of sensory recovery. There was a significant correlation between response to isolated cold stress testing (thermoregulation) and degree of sensory recovery (p less than or equal to 0.02). This method for quantitative analysis of isolated cold stress testing data allows objective evaluation of digital blood flow patterns based on temperature, thereby providing a reliable and objective assessment of the recovery of thermoregulation in the replanted human digit.

Adult↗
PubMed1990

Chronic wrist pain: indications for wrist arthroscopy.

Although arthroscopy represents a new and dynamic diagnostic technique for evaluating the wrist, specific indications for arthroscopic intervention in the wrist are not defined. To place this technique in perspective, we review our experience with 54 consecutive arthroscopies of the radiocarpal and midcarpal joints in 53 patients with chronic wrist pain. On the basis of this review, we believe arthroscopy is indicated for the diagnosis of wrist pain of longer than 3 months' duration. Defects of the triangular fibrocartilage and lesions of the articular cartilage, including loose bodies, are detectable and easily treated with wrist arthroscopy.

Adolescent↗
PubMed1990

Congenital flexion deformities of the proximal interphalangeal joint in children: a subgroup of camptodactyly.

Severe flexion contractures of the proximal interphalangeal joint that are present at birth affect both sexes equally, often involve several digits of the same hand, and show no predilection for the small finger make up a distinct subgroup of the deformity known as camptodactyly. In this series, 20 digits with such severe flexion contractures were treated surgically. In eight digits, the flexor digitorum superficialis tendon was lengthened with or without release of contracted palmar structures. There was no improvement in these digits. In the other 12 digits, the extensor mechanism was realigned and augmented by release or transfer of the flexor digitorum superficialis tendon. All 12 of these digits had good (n = 10) to fair (n = 2) improvement in active and passive extension while retaining adequate flexion, although 9 still had some residual flexion contracture. In this type of camptodactyly, extensor mechanism anomalies appear to be the primary lesion.

Child↗
PubMed1990

Use of isolated cold stress testing in determining normal lower extremity thermoregulation.

Isolated cold stress testing was performed on 72 healthy subjects in order to evaluate the normal thermoregulatory potential of vessel beds in the acral areas of the lower extremity. Two patterns of response were demonstrated: a cool response in approximately 80% of subjects, and a warm pattern in approximately 20%. In the former, the responses to cold stress were more active and the temperatures lower; in the latter, there was little change in temperature in response to the cold stress. Both patterns correlated strongly with initial temperature, and neither pattern correlated with age, sex, or smoking habits. No subjects reported pain, numbness, or discomfort during the test. This study demonstrated that wide variations in thermoregulatory flow were possible without clinical symptoms, and suggested that nutritional blood flow was adequate to meet metabolic demands despite thermoregulatory modulation.

Adolescent↗
PubMed1990

Cerebral palsy. Management of the upper extremity.

Although only a small number of children with cerebral palsy have indications for surgical treatment of dynamic or structural upper-extremity deformities, orthopedic surgery does improve function and appearance of the involved hand, particularly in spastic hemiplegia. For further assessment of the patient after careful physical examination, myoneural nerve blocks and dynamic electromyography are useful. Physical and occupational therapists have an important role as crucial links among parents, patients, and physicians. Surgeons can try to prevent deformity with splints; however, their use in prevention of deformities of the hand has not been validated by scientific studies. Shoulder deformities can be managed with myotomies, tendon transfers, and (if fixed) osteotomies; rarely is arthrodesis used. Elbow flexion and dynamic or fixed deformities greater than 60 degrees are treated by lengthening of the muscles and tendons. Pronation deformities of the forearm are managed by myotomies, lengthenings, and tendon transfers. Wrist flexion deformities can be corrected with tendon lengthenings and transfers. The best results have been obtained with transfer of the flexor carpi ulnaris to the extensor digitorum communis. Finger flexion deformities can be managed satisfactorily with Z-lengthenings of the flexor digitorum superficialis in the forearm; rarely is it necessary to lengthen the flexor digitorum profundus. For adduction deformity of the thumb, division of the proximal or distal insertions of the adductor pollicis and release of the first dorsal interosseus muscle from the first and second metacarpals are preferred.

Arm↗
PubMed1990

Fractures and ligamentous injuries of the wrist.

Rapid diagnosis, appropriate management, and sport-specific rehabilitation are important in the management of any wrist injury in the athlete. The addition of technetium scans, CT, arthroscopy, and MRI in the evaluation of the athlete's wrist has provided valuable and powerful diagnostic tools. The versatility and relatively low invasiveness of arthroscopic intervention and the subsequent early return to activity make this technique especially attractive in the high-performance athlete. Suspicion of potential injuries, complete knowledge of wrist mechanics and anatomy, and a careful physical examination are still the most important tools in the evaluation of wrist injury. It is important to approach each athlete in a patient-oriented manner, taking into account the fact that many of these injuries have the potential to be career ending. Treatment that will provide the best possible long-term wrist function must be the physician's ultimate goal. In addition, the importance of appropriate and activity-specific rehabilitation cannot be overemphasized.

Arthroscopy↗
PubMed1990

Arthrodesis of the metacarpophalangeal joint of the thumb in children and adults. Adjunctive treatment of thumb-in-palm deformity in cerebral palsy.

A hypermobile hyperextension or hyperflexion deformity of the metacarpophalangeal (MCP) joint associated with thumb-in-palm deformity in 90 patients affected by cerebral palsy was treated by arthrodesis with or without soft-tissue procedures. Twenty-two of these patients were adults with closed physes, and 68 were children or adolescents with open growth plates. The MCP joint fusion was usually accompanied by intrinsic muscle lengthening and/or extrinsic tendon transfer, but occasionally it was the only procedure performed to diminish the thumb-in-palm position. Even in four-year-olds, joint fusion was a predictable procedure to establish stability of that joint without disturbing longitudinal or circumferential growth. Measurable function was improved to a mild or moderate degree in 44 of the 50 children who were followed to maturity. Eighteen of the 68 children were unavailable for follow-up evaluation. Six of the 50 followed patients showed no functional improvement, although arthrodesis of the MCP joint occurred in four of the six. The other two patients were operated on when they were 12 years of age and developed a fibrous union that was painless and stable when they were adults. Even those patients who had no functional improvement did have improved appearance and easier control of the affected hand when it was manipulated by the opposite hand. The children were followed to maturity with age-matched cerebral palsy control patients. There was no significant disturbance in growth of those thumbs that had MCP joint fusion when the physes were open.

Adolescent↗
PubMed1989

Thermoregulatory abnormalities of the foot.

Thermoregulatory abnormalities are well known but poorly understood phenomena. Pathologic alterations of microvascular blood flow occur in a variety of diseases of the foot, and often cause severe functional impairment. The structure, function, and methods for testing thermoregulatory abnormalities are reviewed. Pathologic manifestations of abnormal thermoregulation are also discussed.

Body Temperature Regulation↗
PubMed1988

Reflex sympathetic dystrophy of the knee after sensory nerve injury.

Reflex sympathetic dystrophy (RSD) of the knee is an extremely difficult problem to treat. This study examined the possible relationship between isolated injury to the infrapatellar branch of the saphenous nerve (IPBSN) and the etiology and natural course of RSD. Thirty-five patients with clinically significant sympathetic dystrophy of the knee were examined retrospectively. All patients (100%) had clinical evidence of insult to the IPBSN. Thirty-three patients (94%) were found to have vasomotor instability as measured by isolated cold stress testing (ICST). All patients in this population of 33 were treated with vasoactive therapies. Subjective improvement was noted in 20 patients (p = NS). Initial ICSTs of improved and unimproved patients were compared. Baseline temperatures were significantly warmer in patients who improved with therapy (p less than 0.05), and a warmer trend was evident throughout all phases of the test in those who improved compared with those who did not. Eighty percent of patients treated within 1 year improved with one or more vasoactive therapies, whereas only 44 percent improved when treatment was started after 1 year, indicating a significant population difference (p less than 0.05).

Adult↗
PubMed1988

Pathologic fractures of the humerus.

In a study of 57 actual or impending pathologic fractures of the humerus in 52 patients with inoperable cancer treated between 1972 and 1982, we retrospectively reviewed the charts for analysis and comparison of the functional result and pain relief afforded by the various treatments used. Function of the extremity and relief of pain were each graded as excellent, good, fair, or poor using a modification of Perez's rating system. Seven pathologic fractures were treated nonoperatively. These patients generally had only fair pain relief and a poor functional result. Forty-six pathologic fractures were treated with intramedullary fixation using a Rush rod (n = 16), a Küntscher rod (n = 29), or an Ender rod (n = 1); the Neer endoprosthesis was used in four patients. Thirty-one patients received radiation to the humerus. There were seven operative complications, the most common (n = 3) being prominence of an intramedullary rod at the insertion site which required a second minor procedure for advancement of the rod. From this series, we conclude that any patient who has a pathologic fracture or impending fracture of the humerus and a predicted survival of six weeks or more is likely to benefit from rigid internal fixation with an appropriately selected device, adjunctive use of methylmethacrylate, and postoperative local irradiation therapy as needed.

Adult↗
PubMed1987

Arterial stump pressure: a determinant of arterial patency?

Twenty-seven patients with acute injuries to the radial or ulnar arteries had arterial repairs using microvascular techniques. No patient had an ischemic hand secondary to his arterial injury. The overall patency rate for all repaired vessels was 56%. For sharp, clean lacerations, the success rate for repairs was 55%. Repairs of acute, sharp lacerations yielded no better results than delayed reconstructions. The average distal end arterial stump pressure for patent arteries was 66% of mean, while for thrombosed vessels it was 76% of mean; this was not a statistically significant difference (p = 0.9). There was no statistical correlation between forearm arterial patency, age, sex, vessel injured, mechanism of injury, time of repair, or clinically measured distal arterial stump pressure. At the present time, it does not appear to be possible to predict arterial patency by measuring arterial stump pressure at the time of definitive repair.

Arteries↗
PubMed1987

Salvage of lower extremities following combined orthopedic and vascular trauma. A predictive salvage index.

A retrospective review of 676 tibial-fibular fractures and 985 femoral fractures treated over a 71-month period yielded associated major vascular trauma in 12 (1.7%) tibial-fibular fractures and in five (0.5%) femoral fractures. Vascular trauma combined with orthopedic trauma was also identified in four other cases--two disruptions of the pubic symphysis and two dislocations of the knee without fracture. Nine (43%) of the 21 involved limbs were eventually amputated. Limb survival was not related to the temporal relationship of vessel repair to skeletal stabilization; the presence or absence of shock on admission; the presence of associated but repaired venous injury; or the presence of unrelated injuries. Limb survival was related to the interval from injury to arrival in the operating room; the level of arterial injury; and the quantitative degree of muscle, bone, and skin injury. By combining these variables a limb salvage index was established that identified lower extremities likely to require amputation after combined orthopedic and vascular trauma (sensitivity 78%, specificity 100%). Use of this predictive salvage index may prevent the trauma surgeon from attempting to salvage a doomed or useless lower extremity and may thus permit early prosthetic rehabilitation to follow definitive primary amputation.

Adolescent↗
PubMed1986

Thermoregulatory control after upper extremity replantation.

Four patients with complete forearm amputations between the wrist and elbow were analyzed prospectively to determine the interrelationships of thermoregulation to pain, cold intolerance, arterial integrity, venous competence, motor nerve recovery, sensory nerve recovery, and time. Patients were examined at 6 weeks, 3 months, 6 months, 1 year, and 2 years after replantation. Vasomotor regulatory capacity was assessed by isolated cold-stress testing. Pain had diminished in all patients by 6 months to 1 year, regardless of other factors. Cold tolerance and normal thermoregulatory response, as indicated by cold-stress test performances, were temporally related to attainment of two-point sensory discrimination (p less than 0.05), or to motor nerve recovery (p less than 0.05), or to both.

Adolescent↗