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Biomedical subjects

S T Hansen

Publications and source records attributed to S T Hansen.

At least 37 records · Page 2Linked to original sources

Achilles tendon tenodesis to prevent heel pad migration in the Syme's amputation.

In an attempt to prevent migration of the heel pad, 11 patients underwent a combined Syme's amputation and Achilles tendon tenodesis between December 1989 and April 1992. Ten patients healed the Syme's amputation, and one patient failed to heal the surgical wounds and required a below-knee amputation. In all 10 successful Syme's cases, the heel pad has remained stable with no migration, and no skin breakdown at an average follow-up of 18.5 months. Published series of Syme's amputations report that the incidence of heel pad migration is between 7.5% and 45%, and occurs primarily in the post-operative or early rehabilitation stage. We believe that tenodesis of the Achilles tendon is a technically easy addition to the Syme's amputation, that it keeps tension off of the incision during healing, and that it prevents migration of the heel pad.

Achilles Tendon↗

Continuous regional analgesia by intraneural block: effect on postoperative opioid requirements and phantom limb pain following amputation.

The objective of this study was to assess the effectiveness of a previously described technique of regional analgesia (continuous infusion of local anesthetic through a catheter placed at the time of amputation within the exposed sciatic or posterior tibial nerve) on relieving the postoperative pain in a heterogeneous group of patients who underwent lower extremity amputations. A second objective was to determine the effect of such treatment on the incidence and characteristics of phantom limb pain 6 months or more after surgery in the same patients. The study design was retrospective, unblinded, controlled (postoperative pain), and unblinded questionnaire and interview (phantom pain) were utilized. Subjects were inpatients at Harborview Medical Center, University of Washington, Seattle, WA. Nineteen bupivacaine-treated and 40 nonbupivacaine-treated patients who underwent lower extremity amputation subsequent to trauma, infection, long-standing injury (poor or no function), congenital deformity, or burns were evaluated in the postoperative pain management assessment. Nine treated and 12 untreated patients were interviewed in the phantom pain assessment. Bupivacaine 0.5% 2-6 ml/h was infused through a polyamide 20-gauge catheter inserted into the sciatic or posterior tibial nerve sheath under direct vision at the time of surgery. All patients, treated and control, received opioid analgesics systemically during the 72-hour period of study. The postoperative opioid analgesic requirement of treated patients was compared with that of control patients who received opioid analgesics alone. A questionnaire was administered to assess presence, severity, and character of phantom pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Symmetrical peripheral gangrene (purpura fulminans) complicating pneumococcal sepsis.

Bacterial sepsis is only infrequently accompanied by peripheral ischemia. However, we have managed 10 patients with symmetrical peripheral gangrene (purpura fulminans) accompanying pneumococcal sepsis (Streptococcus pneumoniae) during the past 15 years at a single institution. In only two (20%) of these patients could vasoconstrictor administration be implicated as contributory to gangrene. The clinical scenario was characterized by pneumococcal bacteremia, admission to the medical intensive care unit, normal proximal arterial perfusion, and symmetrical full-thickness digital and distal extremity ischemia leading to cutaneous gangrene. Three (30%) of these patients died. The failure of anticoagulant and antiplatelet agents as therapy and the successful reversal of impending digital gangrene in one patient by sympathetic blockade suggest that the initial underlining pathophysiology is vasoconstrictive rather than thrombotic in nature. Effective management includes appropriate antibiotic therapy, avoidance of early operative intervention, conservative local débridement, and secondary skin grafting.

Adrenal Cortex Hormones↗

Foot and ankle manifestations of Charcot-Marie-Tooth disease.

The term Charcot-Marie-Tooth disease represents a spectrum of neurological dysfunction more recently described as hereditary motor-sensory neuropathies. An abnormality of myelination is thought to be responsible for the clinical manifestations. While histological findings have been well described, the exact biochemical basis for this disorder remains unknown. Over one half of patients with Charcot-Marie-Tooth disease manifest foot and ankle problems, including pain, weakness, deformity, and, rarely, paresthesias. Characteristic patterns of neuromuscular weakness have been identified. Bilateral pes cavovarus is the most common pathologic foot deformity seen. The specific components include hindfoot varus, anterior or forefoot cavus, and, often clawtoes. The etiology of this abnormal foot posture usually results from tibialis posterior overpowering peroneus brevis coupled with peroneus longus overpowering tibialis anterior. Multiple treatment options have been described. Rationale for specific tendon transfers, soft tissue release, osteotomies, and arthrodesis is discussed. Results of surgical intervention are difficult to interpret and compare because of the wide spectrum of both neurological dysfunction and described operative procedures. In the presence of flexible deformity, early soft tissue release and tendon transfers may help prevent or delay more extensive bony procedures. The clinical results of triple arthrodesis in the Charcot-Marie-Tooth disease patient appear to deteriorate with time. Genetic transmission, progression of the neurological dysfunction, flexibility of the deformity, distribution of muscular weakness, and anticipated foot demands vary a great deal within this patient population. Treatment decisions, therefore, must be individualized and based upon a clear history, careful examination, and well-defined patient goals.

Ankle Joint↗

Plate fixation of femoral shaft fractures in multiply injured children.

A study was done of twelve patients (seven boys and five girls) who, because of multiple injuries or a head injury, had been managed with compression plating of a unilateral or bilateral femoral-shaft fracture at a level-I trauma center from 1986 through 1990. The patients had a total of fifteen fractures. The average age at the time of the injuries was eight years (range, five years to nine years and eleven months). There were nine closed fractures and six open fractures; three of the open fractures were Grade I; two, Grade II; and one, Grade IIIA, according to the criteria of Gustilo et al. Each patient had an average of three associated injuries. All fifteen fractures had healed clinically and radiographically at an average of eight weeks (range, six to twelve weeks) after the operation. There were no infections. Anatomical alignment was obtained in fourteen limbs. One fracture healed with 13 degrees of anterior angulation. The compression plates were removed at an average of ten months (range, three to twenty-four months) after the index operation. At the latest follow-up evaluation (average, twenty-six months; range, eleven to fifty-seven months), no patient had restriction of activities due to the femoral fracture. Scanograms revealed overgrowth of the injured femur averaging 0.9 centimeter (range, 0.3 to 1.4 centimeters) in seven patients who had an uninjured contralateral femur. We believe that plate fixation of the femur is a good treatment option for children who have a femoral shaft fracture and a major head injury or multiple injuries, or both.

Bone Plates↗

Triple arthrodesis using internal fixation in treatment of adult foot disorders.

Forty adult patients with 44 fused feet were evaluated at an average of 4.9 years after triple arthrodesis. The average age of the patients at operation was 41 years. All operations were performed by a specific technique using rigid internal fixation with screws. Outcome was graded using the clinical criteria of Hallgrimsson as modified by Angus and Cowell. Function was evaluated according to modified Arthritis Impact Measurement Scales (AIMS). Radiographic evaluation included measurement of lateral talocalcaneal angle, lateral talometatarsal angle, and anteroposterior (AP) talometatarsal angle on standing or simulated weight-bearing radiographs. Thirty-four feet had good results, six had fair results, and there were four failures. The average patient could function painlessly on flat surfaces in nonstrenuous activities and had only occasional mild pain with more vigorous activities. In roentgenographic parameters, there was an average improvement of 17 degrees in the lateral talometatarsal angle, 11 degrees improvement in the lateral talocalcaneal angle, and an improvement of 18 degrees in the AP talometatarsal angle. There were two pseudarthroses, no recurrences, and two unsatisfactory corrections. When carefully done, triple arthrodesis can restore an adult patient with a disabling foot disorder to normal function and minimal pain.

Adolescent↗

Intraarticular fractures of the foot. Talus and lesser tarsals.

In the absence of historical comparative data for the treatment of tarsal fractures, commonly abided maxims of trauma care are noteworthy. A displaced fracture involving an articular surface or a fracture interrupting a mechanical axis is treated by open reduction and internal fixation. Rigid fixation is followed as early as possible with active and passive mobilization. Unlike long bones, whose motion and fracture patterns (i.e., segmental, transverse, and oblique) are understood, the tarsal bones are small bones with complex shapes and restricted motion. As a result, tarsal injuries most often occur with multiple ligamentous and bony injuries. Articular step-off is difficult to establish roentgenographically, the blood supply is tenuous, and fixation is largely dependent on screws and Kirschner wires. Good outcome can be obtained by following principles of internal fixation established in treatment of major joint injuries.

Bone Screws↗

Scarred muscle excision for the treatment of established ischemic contracture of the lower extremity.

Nine patients with rigid equinocavovarus contractures of the foot and ankle after ischemic episodes of the leg were treated from 1986 to 1989. The ischemic contractures occurred after tibial and fibular fractures in six cases, and after a trimalleolar ankle fracture, an electrical burn, and cardiac bypass surgery in one case each. Previous tendon and nerve releases had failed. The scarred portion of the various involved muscles of the deep posterior compartment were widely excised along with the respective tendons. A variety of additional foot procedures were generally necessary to obtain a plantigrade foot. Night splinting to maintain a plantigrade foot was prescribed for all patients.

Adolescent↗

Traumatic subluxation/dislocation of the peroneal tendons.

Traumatic subluxation/dislocation of the peroneal tendons has been reported following a variety of sports-related activities. The peroneal musculature contracts reflexively during the injury and overcomes the restraining soft tissue. The tendons can then dislocate anteriorly from behind the distal fibula. Some patients have anatomical variations of the posterolateral ankle that predispose them to injury. If the physician is unaware of the injury, the diagnosis may be missed in the acute setting and can develop into a chronic, disabling condition. Treatment of the acute injury is controversial because advocates exist for both conservative and surgical therapies. The chronic, painful lesion should be treated operatively. A tremendous number of surgical procedures have been described for the treatment of chronic tendon dislocations. Choice of a surgical procedure depends upon the anatomy of the peroneal groove and the retinaculum, and the nature of the damage to the area.

Adolescent↗

Operative management of displaced femoral head fractures: case-matched comparison of anterior versus posterior approaches for Pipkin I and Pipkin II fractures.

Because of the controversy surrounding the selection of the surgical approach for the operative management of femoral head fractures, we retrospectively reviewed the combined experience with femoral head fractures at two major trauma centers. Forty-three femoral head fractures in 41 patients were identified. Twenty-six of the 43 fractures were Pipkin types I and II, and were managed operatively. Of the 26 patients, 12 with > 2 years of follow-up were managed with posterior surgical approaches and 12 with anterior surgical approaches. These patients were assessed with respect to operative time, estimated blood loss and function, and the radiographs for reduction, avascular necrosis, and heterotopic ossification. There was a significant decrease in operative time, estimated blood loss, and improved visualization and fixation with the anterior approach; however, there was a significant increase in functionally significant heterotopic ossification. The functional results in the two groups were identical; 67% good and excellent in each. There were no cases of avascular necrosis of the femoral head associated with an anterior approach. Because of the greater ease of access to the fracture, the anterior approach is recommended when operative reduction of a displaced Pipkin type I or II is indicated, but newer methods of minimizing heterotopic ossification must be developed.

Adult↗

Ankle arthrodesis using internal screw fixation.

Ankle arthrodesis treated by external fixation frequently results in complications from pin tract infections, loss of position, nonunion, and malunion. A method of ankle arthrodesis using 6.5-mm cancellous screws as the primary fixation hardware was developed. The most important screw is placed from the posterior malleolus into the neck and head of the talus, and medial and lateral malleolar screws are added to secure fixation. Near-normal anatomy is maintained with this technique because little or no bone, only cartilage, is removed. Earlier cases were all done through an anterior approach. Later, special techniques were developed for placing screws and strain-relieving bone grafting was added to promote union. Twenty-three cases that were treated by the earlier technique are reviewed. The overall fusion rate was 74%. Three conditions (avascular talus, pyarthrosis, and spasticity) were identified that placed patients at high risk for failure of fusion. Of the patients who were not in a high-risk group, only one had a delayed union. When the high-risk patients were not included in the statistics, the fusion rate was 93%. The evolved technique shows great promise for accurate and trouble-free ankle arthrodesis.

Adult↗

Objective criteria accurately predict amputation following lower extremity trauma.

MESS (Mangled Extremity Severity Score) is a simple rating scale for lower extremity trauma, based on skeletal/soft-tissue damage, limb ischemia, shock, and age. Retrospective analysis of severe lower extremity injuries in 25 trauma victims demonstrated a significant difference between MESS values for 17 limbs ultimately salvaged (mean, 4.88 +/- 0.27) and nine requiring amputation (mean, 9.11 +/- 0.51) (p less than 0.01). A prospective trial of MESS in lower extremity injuries managed at two trauma centers again demonstrated a significant difference between MESS values of 14 salvaged (mean, 4.00 +/- 0.28) and 12 doomed (mean, 8.83 +/- 0.53) limbs (p less than 0.01). In both the retrospective survey and the prospective trial, a MESS value greater than or equal to 7 predicted amputation with 100% accuracy. MESS may be useful in selecting trauma victims whose irretrievably injured lower extremities warrant primary amputation.

Adult↗

Salvage of Lisfranc's tarsometatarsal joint by arthrodesis.

Sixteen patients with fractures or fracture-dislocations of the tarsometatarsal (Lisfranc) joint who failed initial treatment were salvaged by arthrodesis using a technique of rigid internal fixation. Preoperative symptoms included local pain in all patients, progressive flatfoot deformity with forefoot abduction in 12 patients, and ankle or lateral impingement pain in five. The technique involved exposing the joint, denuding it of cartilage and scar, and reduction and fixation with lag screws. A total of 49 joints were fused. When significant deformity was present, reduction was performed before arthrodesis. Clinically symptomatic and radiographically proven nonunion occurred in four sites in three patients. One healed after revision. Good to excellent results were obtained in 11 patients (69%). Five patients had a fair or poor results. All but one of the patients were subjectively improved. Four patients were symptom free and returned to their preinjury lifestyles. Accurate reduction and early treatment had a significant positive relationship with outcome. Injuries that occurred in the workplace and those that incurred a long delay until treatment showed a significant negative correlation to outcome. Neither the age of the patient nor the number of joints fused had a significant impact on result.

Adolescent↗

Internal fixation of children's fractures of the lower extremity.

Lower grade fractures are by definition stable and almost always treated with casting or functional splinting. The best kind of fixation for the higher grade fractures, however, differs between adults and children. Appropriate treatments are discussed, and case-study illustrations are provided. Background on the anatomy of the tibia and femur is included.

Adolescent↗