Patterns of growth and body condition in sea otters from the Aleutian archipelago before and after the recent population decline.

1. Growth models for body mass and length were fitted to data collected from 1842 sea otters Enhydra lutris shot or live-captured throughout south-west Alaska between 1967 and 2004. Growth curves were constructed for each of two main year groups: 1967-71 when the population was at or near carrying capacity and 1992-97 when the population was in steep decline. Analyses of data collected from animals caught during 2004, when the population density was very low, were precluded by a small sample size and consequently only examined incidentally to the main growth curves. 2. Growth curves demonstrated a significant increase in body mass and body length at age in the 1990s. Asymptotic values of body mass were 12-18% higher in the 1990s than in the 1960s/70s, and asymptotic values for body length were 10-11% higher between the same periods. Data collected in 2004 suggest a continued increase in body size, with nearly all data points for mass and length falling significantly above the 1990s growth curves. 3. In addition to larger asymptotic values for mass and length, the rate of growth towards asymptotic values was more rapid in the 1990s than in the 1960s/70s: sea otters reached 95% of asymptotic body mass and body length 1-2 years earlier in the 1990s. 4. Body condition (as measured by the log mass/log length ratio) was significantly greater in males than in females. There was also an increasing trend from the 1960s/70s through 2004 despite much year-to-year variation. 5. Population age structures differed significantly between the 1960s/70s and the 1990s with the latter distribution skewed toward younger age classes (indicating an altered lx function) suggesting almost complete relaxation of age-dependent mortality patterns (i.e. those typical of food-limited populations). 6. This study spanned a period of time over which the population status of sea otters in the Aleutian archipelago declined precipitously from levels at or near equilibrium densities at some islands in the 1960s/70s to < 5% of estimated carrying capacity by the late 1990s. The results of this study indicate an improved overall health of sea otters over the period of decline and suggest that limited nutritional resources were not the cause of the observed reduced population abundance. Our findings are consistent with the hypothesis that the decline was caused by increased killer whale predation.

Epithelioid sarcoma: clinical, MR imaging and pathologic findings.

OBJECTIVE: To report and describe the MR imaging features of eight new cases of this rare soft tissue sarcoma and correlate them with the clinical and histologic findings. DESIGN AND PATIENTS. Retrospective analysis was carried out for the MR imaging characteristics and histologic findings of eight patients with pathologically proven epithelioid sarcoma and the literature was reviewed. Findings were correlated in each case with the patient's clinical presentation and eventual outcome. RESULTS: The patients, whose primary tumors ranged from 2.5 cm to 19 cm in maximum dimension, were 1 to 90 years of age. Tumors involved the extremities ( n=5), the scalp ( n=2) and the paraspinal muscles ( n=1). Five tumors presented as well-defined, frequently painful, deeply situated masses and three as subcutaneous nodules or cutaneous ulcers with no palpable mass. Four patients had associated regional lymphadenopathy and one had distant metastases at diagnosis. MR imaging showed tumor infiltration of adjacent tissues in seven patients. Signal characteristics reflected varying degrees of cellularity, and the presence of necrosis, hemorrhage, fibrosis, hyalinization and inflammation. Bone marrow involvement was demonstrated in one patient. Clinical outcomes were generally poor. CONCLUSIONS: Epithelioid sarcoma is an aggressive soft tissue sarcoma with a varied clinical presentation, growth pattern, MR signal characteristics and histologic picture. The tumor favors the distal extremities and is commonly infiltrative and accompanied by enlarged regional lymph nodes. This neoplasm may present as an intramuscular mass but should also be suspected in patients with ulcerating cutaneous nodules with or without regional lymphadenopathy.

Chemical anesthesia of northern sea otters (Enhydra lutris): results of past field studies.

Between 1987 and 1997, we chemically immobilized 597 wild sea otters (Enhydra lutris) in Alaska for the collection of biological samples or for surgical instrumentation. One drug-related sea otter fatality occurred during this time. Fentanyl in combination with diazepam produced consistent, smooth inductions with minimal need for supplemental anesthetics during procedures lasting 30-40 min. Antagonism with naltrexone or naloxone was rapid and complete, although we observed narcotic recycling in sea otters treated with naloxone. For surgical procedures, we recommend a fentanyl target dose of 0.33 mg/kg of body mass and diazepam at 0.11 mg/kg. For nonsurgical biological sample collection procedures, we recommend fentanyl at 0.22 mg/kg and diazepam at 0.07 mg/kg. We advise the use of the opioid antagonist naltrexone at a ratio of 2:1 to the total fentanyl administered during processing.

Long-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns.

We use age distributions of sea otters (Enhydra lutris) found dead on beaches of western Prince William Sound, Alaska, between 1976 and 1998 in conjunction with time-varying demographic models to test for lingering effects from the 1989 Exxon Valdez oil spill. Our results show that sea otters in this area had decreased survival rates in the years following the spill and that the effects of the spill on annual survival increased rather than dissipated for older animals. Otters born after the 1989 spill were affected less than those alive in March 1989, but do show continuing negative effects through 1998. Population-wide effects of the spill appear to have slowly dissipated through time, due largely to the loss of cohorts alive during the spill. Our results demonstrate that the difficult-to-detect long-term impacts of environmental disasters may still be highly significant and can be rigorously analyzed by using a combination of population data, modeling techniques, and statistical analyses.

Clinical and radiological aspects of idiopathic diabetic muscle infarction. Rational approach to diagnosis and treatment.

The systemic effects of diabetes mellitus are well recognised. The heart, kidney, central and peripheral nervous systems, and the distal parts of the limbs are often the site of end-organ damage resulting from ischaemia. Infarction of large muscle groups in the limb, not associated with gangrene, is uncommon. There have been few reported cases other than radiological descriptions of diabetic muscle infarcts. While previous reports have illustrated some of the clinical and radiological characteristics of this condition, the paucity of published cases makes it difficult to determine the most appropriate methods of diagnosis and treatment. During a five-year period we treated 14 patients with diabetes mellitus, aged from 32 to 59 years, who were referred to a musculoskeletal oncology service for suspected soft-tissue sarcoma, but were subsequently found to have a diabetic muscle infarct. Closed needle biopsy was performed in 13 without complications. In 12 patients, the symptoms resolved without surgical treatment.

Neuropathy secondary to pigmented villonodular synovitis of the hip.

Pigmented villonodular synovitis is a benign proliferative process of unknown origin that may cause extensive bone and joint destruction. Patients with this condition typically present with symptoms of mild discomfort and associated stiffness of the involved joint; however, the spectrum of presentations is broad. Although pigmented villonodular synovitis begins in, and usually is confined within, a synovium-lined joint, it may extend beyond the joint capsule and present as a soft tissue mass. Three cases of a previously unrecognized presentation of pigmented villonodular synovitis of the hip joint are presented. The authors believe these to be the first reported cases in the English language literature of pigmented villonodular synovitis of the hip seen with femoral or sciatic neuropathy.

Disruption of sutured pulmonary valve in Fontan operation.

Two patients who had undergone a Fontan operation presented late with considerable disruption of a sutured pulmonary valve. Both patients had increasing ascites, decreased exercise tolerance, atrial arrhythmias, high right atrial pressure, and a large ratio of pulmonary blood flow to systemic blood flow. At operation, the main pulmonary artery was closed either by suturing the anterior and posterior walls together immediately distal to the pulmonary valve or by reinforcing the resutured pulmonary valve with a polytetrafluoroethylene patch. Both patients had an uneventful postoperative course, with disappearance of the symptoms and return of sinus rhythm. Although it is tempting to simply suture the usually thickened pulmonary valve in the Fontan operation, approximation of the pulmonary artery walls or patch reinforcement is necessary to minimize disruption.

A comparison of the prognoses for deep and subcutaneous sarcomas of the extremities.

We evaluated 172 patients who had a soft-tissue sarcoma of the extremity in order to determine whether the prognosis for a subcutaneous sarcoma was better than that for a deep sarcoma. At a median of thirty-six months after the biopsy or definitive operation at our hospital, six of the fifty-two patients who had had a subcutaneous sarcoma had died and one had had a local recurrence; in contrast, forty of the 120 patients who had had a deep sarcoma had died and eight had had a local recurrence. Twenty-five (48 percent) of the subcutaneous sarcomas were malignant fibrous histiocytomas, and thirty-eight (73 percent) were small (five centimeters or less in the largest dimension). The three-year estimates of disease-free survival were 85 percent for the patients who had a subcutaneous sarcoma and 54 per cent for those who had a deep sarcoma (p = 0.002). Although the survival estimates remained significantly different when the groups were matched for histological diagnosis and for intracompartmental location (p = 0.0001 and 0.0006, respectively), they were not significantly different when the groups were matched for the size of the tumor (p = 0.42). A Cox proportional-hazards model confirmed that a tumor size of more than five centimeters and the histological grade are the most significant prognostic factors (p = 0.0007 and p = 0.004, respectively): a tumor size of more than five centimeters was associated with a relative risk of 3.5 (95 per cent confidence interval, 1.7 to 7.3), and a higher histological grade was associated with a relative risk of 4.0 (95 per cent confidence interval, 1.6 to 10.3). Subcutaneous location, when considered separately, was not a significant prognostic factor (p = 0.45). The data indicate that a tumor size of more than five centimeters is a more important prognostic indicator than histological diagnosis, depth, or intracompartmental location.

Extended aortic valvuloplasty for recurrent valvular stenosis and regurgitation in children.

Recurrent significant aortic valvular stenosis or regurgitation, or both, after balloon or open valvotomy in pediatric patients often necessitates aortic valve replacement. In an attempt to preserve the aortic valve, we performed extended aortic valvuloplasty in 21 children with recurrent aortic valve stenosis or regurgitation from January 1989 to March 1993. Previous related procedures were one open aortic valvotomy or more (n = 15), balloon valvotomy (n = 4), balloon valvotomy after surgical valvotomy (n = 1), and repair of iatrogenic valve tear (n = 1). Mean age at the time of the extended aortic valvuloplasty was 6 +/- 3.4 years. Mean pressure gradient across the aortic valve was 56 +/- 12 torr. Regurgitation was moderate (grade 2 to 3) in nine and severe (grade 4) in 12 patients. Extended aortic valvuloplasty techniques consisted of thinning of valve leaflets (n = 15), augmentation of scarred and retracted leaflets with autologous pericardium (n = 11), resuspension of the augmented leaflet (n = 14), release of the rudimentary commissure from the aortic wall (n = 5), extension of the valvotomy incision into the aortic wall on both sides of the commissure (n = 20), patch repair of the sinus of Valsalva perforation (n = 1), reapproximation of tears (n = 5), and narrowing of the ventriculoaortic junction (n = 2). No operative deaths occurred. The postoperative mean pressure gradient, assessed by most recent Doppler echocardiography or cardiac catheterization at a follow-up of 18 +/- 6 months, was 19 +/- 6 torr (p < 0.01 versus the preoperative gradient). Aortic regurgitation was absent in 13, mild in 6, and moderate-to-severe, necessitating subsequent aortic valve replacement, in 2. This short-term experience indicates that extended aortic valvuloplasty is a safe and effective surgical approach that minimizes the need for aortic valve replacement in children with significant recurrent aortic valve stenosis or regurgitation.

Triple-phase bone scan findings in aggressive fibromatosis. Before and after radiation therapy.

The authors present comparative triple-phase bone scan findings in three cases of histologically proven aggressive fibromatosis both before (initial evaluation) and after radiation therapy. The purpose of the study was to compare triple-phase bone scan findings in aggressive fibromatosis both before and after radiation therapy and to determine whether any additional physiological information could be obtained. Before radiation therapy, the triple-phase bone scintigraphy demonstrated increased flow and radiotracer pooling in the areas of tumors on dynamic flow and immediate blood pool images, respectively. However, the delayed static images demonstrated variable radiotracer uptake. When compared to preradiation therapy triple-phase bone scan, decreased vascularity was well demonstrated in all three patients after radiation therapy. In addition, it also provided information regarding the changes in the size and extent of tumor, noninvaded underlying bone, and remainder of the skeleton. This additional information can be particularly useful in patients with equivocal or questionable histologic diagnosis especially from small, unrepresentative biopsies.

Fibrous lesions of bone.

Fibrous lesions of bone include entities with a wide range of radiographic appearance and clinical behavior. Many benign fibrous lesions, such as medial supracondylar defects, fibrous cortical defects, and nonossifying fibromas have typical radiographic appearances and usually are self-limited. Desmoplastic fibromas and benign fibrous histiocytomas are less common, behave more aggressively, and usually require biopsy and surgical management. Fibrous dysplasia varies from solitary clinically unimportant lesions to wide-spread, deforming skeletal involvement that can lead to severe functional impairment and, rarely, even to death. Malignant fibrous lesions, including malignant fibrous histiocytomas and fibrosarcoma, produce aggressive lytic lesions, which require careful anatomic staging, accurate biopsy, and aggressive and appropriate treatment.

Inferior vena cava interruption with the Hunter-Sessions balloon: eighteen years' experience in 191 cases.

Over a period of 18 years, 191 consecutive patients had interruption of the inferior vena cava with the Hunter-Sessions balloon for complications of deep venous thrombosis and pulmonary embolism. Causes of deep venous thrombosis and pulmonary embolism included the postoperative state (33%), cancer (32%), and stroke (11%). There were 93 females and 98 males; ages ranged from 17 to 90 years (average, 57 years). Indications for placement of the Hunter-Sessions balloon were as follows: contraindication to anticoagulants (33%), anticoagulant complications (24%), pulmonary embolism despite anticoagulants (45%), and others including inferior vena cava thrombus (12%). Sixty-eight percent had clinical phlebitis and 36% had positive venography results. Pulmonary embolism had occurred in 165 patients (86%). It was diagnosed by ventilation-perfusion scanning (75%), angiography (23%), or on clinical grounds (2%) in patients with confirmed deep venous thrombosis. At the time of the procedure 52% were in significant cardiopulmonary distress, and 10% were intubated and on respirators. Transjugular placement was done in 188 patients, and transfemoral placement was performed in three. All All tolerated inferior vena cava interruption. Thirty patients (15%) died while in the hospital an average of 21 days after balloon placement, which was unrelated to the deaths. Follow-up was 45 months. Ninety-four patients are dead, 95 are alive, and the status of two patients is unknown. Twenty-nine of 64 patients (45%) who died after they left the hospital died of cancer. At last follow-up, 75% of patients had legs free of edema and 25% had need for elastic stockings. No malfunction or migration has occurred with the device. No patient had a pulmonary embolism while in the hospital after insertion of the Hunter-Sessions balloon, and no patient died of pulmonary embolism. Late minor pulmonary embolism occurred in three patients.

Evaluation of patients for high tibial osteotomy.

Fifty-one osteoarthritic knees evaluated by arthroscopic, roentgenographic, and clinical examinations prior to high tibial valgus osteotomy were reevaluated roentgenographically and clinically after a minimum follow-up period of five years (average, 6.2 years; range, 5-8.3 years). The number of good and excellent results decreased over time but was unrelated to the preosteotomy condition of the lateral and patellofemoral compartments as documented by arthroscopy. Knees with 7 degrees to 13 degrees of valgus angulation at the follow-up evaluation had significantly better results than knees with less than 7 degrees of valgus, regardless of the arthroscopic findings. Preosteotomy arthroscopic findings had no predictive value in evaluating patients for this procedure.

Soft tissue tumors of the foot and ankle.

Seven patients with malignant soft tissue tumors of the foot and ankle were retrospectively reviewed. Emphasis was placed on the value of various diagnostic modalities used preoperatively for staging and the adequacy of treatment rendered using current tumor surgery principles. The malignant tumors included synovial cell sarcoma (four), clear cell sarcoma (one), fibrosarcoma (one), and melanoma (one). Surgical management of the malignant lesions included intracapsular excision, marginal excision, wide excision, and radical amputation. Preoperative diagnostic and staging studies that were found to be helpful include ultrasonography, xeroradiography, triple-phase bone scan, and CT and magnetic resonance imaging (MRI) scans. Surgical guidelines include the use of longitudinal skin incisions to obtain excisional biopsies of smaller lesions, keeping the tourniquet inflated until either a benign diagnosis is made or until the definitive procedure is performed. Wide excision or partial foot versus radical amputation may be required depending on the size, location, and extent of malignant soft tissue sarcomas.

Lesser digital arthrodesis.

Arthrodesis at the proximal interphalangeal joint is a surgical procedure useful when dealing with semireducible or nonreducible contractures of the lesser digits. When arthrodesis of the proximal interphalangeal joint is performed, there is conversion of the retrograde dorsal buckling force of the long extensor tendon to a plantargrade straightening force of the flexor tendon. This occurs as a result of the rigid strut created at the arthrodesis site. If metatarsal equinus is present, arthrodesis can help reduce this deformity and eliminate plantar pressure contributing to submetatarsal tyloma. An arthroplasty procedure does not resist deforming forces and is more useful in correcting painful deformities where flexibility is desired postoperatively. It is therefore important, even in "simple" digital surgery, to understand the etiology of the pathology and identify and structure the goals of the surgery. The end-to-end arthrodesis offers the advantage of being easy to perform, relatively free of complication, and able to maintain the length of the digit. A fixation device, such as a Kirschner wire or monofilament wire, may be needed to maintain the correction. Its inherent complications have been described. It can be relatively unstable. The peg in hole arthrodesis offers the advantage of better stability which does not necessarily require internal fixation. There is also rapid bone healing due to the side-to-side configuration of the arthrodesis site. The procedure is more complicated and time consuming to perform than an end-to-end procedure. There is more shortening in the peg in hole. Taking these factors into account, the surgeon should choose the procedure which best meets the preoperative criteria and expected postoperative results.