Duane M. Ilstrup

Malignant peripheral nerve sheath tumors. A clinicopathologic study of 120 cases

A review was done of 120 cases of malignant peripheral nerve sheath tumor (MPNST) seen during a 71‐year period. Of the 120 patients, 52 were males and 68 were females with a mean age at diagnosis of 35.3 years; 12 patients were younger than 20 years. The series included 62 (52%) patients with neurofibromatosis, 13 (11%) with postradiation sarcomas, and 19 (16%) with metaplastic foci. The incidence of MPNST arising in neurofibromatosis was 4.6% in the current series and 0.001% in the general clinic population. Tumors> 5 cm and the presence of neurofibromatosis adversely affected the prognosis (P <0.05). When both features were present, survival was greatly decreased. Patients with tumor in the extremities did better than those with head or neck lesions. Metaplastic foci or previous radiation at the tumor site did not alter the prognosis. Each tumor was graded 1 to 4 on the basis of cellularity, pleomorphism, mitotic index, and necrosis. No significant correlation was noted between survival and either grade or mitotic rate. Survival was improved when total rather than subtotal resection was done. This was most marked in patients with a small lesion, which may reflect the difficulty in adequately excising large tumors. Adjuvant radiation or chemotherapy did not appear to affect survival. The MPNST is an aggressive uncommon neoplasm, and large tumor size, the presence of neurofibromatosis, and total resection are the most important prognostic indicators.

Effect of femoral head size on wear of the polyethylene acetabular component.

A technique was developed to determine the wear of the acetabular component of a total hip replacement by examination of standardized initial and follow-up radiographs. Three hundred and eighty-five hips were followed for at least 9.5 years after replacement. The least amount and rate of linear wear were associated with use of a femoral head that had a diameter of twenty-eight millimeters (p less than 0.001). The greatest amount and mean rate of linear wear occurred with twenty-two-millimeter components, but these differences were not statistically significant. The greatest volumetric wear and mean rate rate of volumetric wear were seen with thirty-two-millimeter components (p less than 0.001). A wider radiolucent line in acetabular Zone 1 was associated with use of the thirty-two-millimeter head. The amounts of resorption of the proximal part of the femoral neck and of lysis of the proximal part of the femur both correlated positively with the extent of linear and volumetric wear; this suggests an association between the amount of debris from wear and these changes in the femoral neck and proximal part of the femur.

The natural history of lone atrial fibrillation. A population-based study over three decades

From 1950 to 1980, 3623 patients from Olmsted County, Minnesota, were found to have atrial fibrillation. Ninety-seven of these patients (2.7 percent), who were 60 years old or younger at diagnosis, had lone atrial fibrillation (atrial fibrillation in the absence of overt cardiovascular disease or precipitating illness), and their data were reviewed to determine the incidence of thromboemboli. Twenty of these patients (21 percent) had an isolated episode of atrial fibrillation, 56 (58 percent) had recurrent atrial fibrillation, and 21 (22 percent) had chronic atrial fibrillation. The total follow-up period was 1440 person-years, with a mean of 14.8 years per patient. The mean age at diagnosis was 44 years. Nineteen cardiovascular events occurred in 17 patients; 4 patients had strokes thought to be due to emboli from atrial fibrillation, and 4 had myocardial infarctions without overt evidence of previous coronary artery disease. The probability of survival at 15 years was 94 percent among the patients with lone atrial fibrillation. At 15 years, 1.3 percent of the patients had had a stroke on a cumulative actuarial basis. On an actuarial basis, there was no difference in survival or in survival free of stroke among the patients with the three types of lone atrial fibrillation (i.e., isolated, recurrent, and chronic). We conclude that lone atrial fibrillation in patients under the age of 60 at diagnosis is associated with a very low risk of stroke. This suggests that routine anticoagulation may not be warranted.

Long-Term Outcome in Patients Undergoing Surgical Repair of Tetralogy of Fallot

BACKGROUND Although corrective surgery for tetralogy of Fallot has been available for more than 30 years, the occurrence of late sudden death in patients in whom surgery was apparently successful remains worrisome. METHODS We studied long-term survival among 163 patients who survived 30 days after complete repair of tetralogy of Fallot, examining follow-up hospital records and death certificates when relevant. RESULTS The overall 32-year actuarial survival rate among all patients who survived surgery was 86 percent, as compared with an expected rate of 96 percent in a control population matched for age and sex (P < 0.01). Thirty-year actuarial survival rates were calculated for the patient subgroups. The survival rates among patients less than 5 years old, 5 to 7 years old, and 8 to 11 years old were 90, 93, and 91 percent, respectively--slightly less than the expected rates (P < 0.001, P = 0.06, and P = 0.02). Among patients 12 years old or older at the time of surgery, the survival rate was 76 percent, as compared with an expected rate of 93 percent (P < 0.001). The performance of a palliative Blalock-Taussig shunt procedure before repair, unlike the performance of a Waterston or Potts shunt procedure, was not associated with reduced long-term survival, nor was the need for a trans-annular patch at the time of surgery. Independent predictors of long-term survival were older age at operation (P = 0.02) and a higher ratio of right ventricular to left ventricular systolic pressure after surgery (P = 0.008). Late sudden death from cardiac causes occurred in 10 patients during the 32-year period. CONCLUSIONS Among patients with surgically repaired tetralogy of Fallot, the rate of long-term survival after the postoperative period is excellent but remains lower than that in the general population. The risk of late sudden death is small.

Natural history of untreated colonic polyps

The natural history of untreated colonic polyps is uncertain. A retrospective review of Mayo Clinic records from a 6-yr period just before the advent of colonoscopy identified 226 patients with colonic polyps greater than or equal to 10 mm in diameter in whom periodic radiographic examination of the colon was elected over excisional therapy. In all patients, follow-up of polyps spanned at least 12 mo (mean, 68 mo; range, 12-229 mo) and included at least two barium enema examinations (mean, 5.2; range, 2-17). During the follow-up period, 83 polyps (37%) enlarged. Twenty-one invasive carcinomas were identified at the site of the index polyp at a mean follow-up of 108 mo (range, 24-225 mo). Actuarial analysis revealed that the cumulative risk of diagnosis of cancer at the polyp site at 5, 10, and 20 yr was 2.5%, 8%, and 24%, respectively. In addition, 11 invasive cancers were found at a site remote from the index polyp during the same follow-up period. These data further support the recommendation for excision of all colonic polyps greater than or equal to 10 mm in diameter. Periodic examination of the entire colon is recommended in this group of patients to identify neoplasms arising at a site remote from the index polyp. Although this study has limitations inherent to any retrospective analysis, comparable prospective data are unlikely to be available in the future because of the current widespread availability of colonoscopy.

Risk Factors for Prosthetic Joint Infection: Case-Control Study

We conducted a matched case-control study to determine risk factors for the development of prosthetic joint infection. Cases were patients with prosthetic hip or knee joint infection. Controls were patients who underwent total hip or knee arthroplasty and did not develop prosthetic joint infection. A multiple logistic regression model indicated that risk factors for prosthetic joint infection were the development of a surgical site infection not involving the prosthesis (odds ratio [OR], 35.9; 95% confidence interval [CI], 8.3-154.6), a National Nosocomial Infections Surveillance (NNIS) System surgical patient risk index score of 1 (OR, 1.7; 95% CI, 1.2-2.3) or 2 (OR, 3.9; 95% CI, 2.0-7.5), the presence of a malignancy (OR, 3.1; 95% CI, 1.3-7.2), and a history of joint arthroplasty (OR, 2.0; 95% CI, 1.4-3.0). Our findings suggest that a surgical site infection not involving the joint prosthesis, an NNIS System surgical patient risk index score of 1 or 2, the presence of a malignancy, and a history of a joint arthroplasty are associated with an increased risk of prosthetic joint infection.

Long-term outcome after surgical repair of isolated atrial septal defect : follow-up at 27 to 32 years

BACKGROUND Atrial septal defects have been surgically correctable for more than 30 years. The long-term survival rates among patients treated in the early era of cardiac surgery are poorly documented, but such data are of critical importance to the future medical care, employability, and insurability of these patients. METHODS To determine the natural history of surgically corrected atrial septal defects, we studied all 123 patients who underwent repair of an isolated defect (ostium secundum or sinus venosus) at the Mayo Clinic between 1956 and 1960, 27 to 32 years after the procedure. The follow-up status of all patients was determined by written questionnaires and telephone interviews. Hospital records and death certificates were obtained if interim hospitalization or death had occurred. RESULTS The overall 30-year actuarial survival rate among survivors of the perioperative period was 74 percent, as compared with 85 percent among controls matched for age and sex. The perioperative mortality was 3.3 percent (four deaths). Actuarial 27-year survival rates among patients in the younger two quartiles according to age at operation (less than or equal to 11 years and 12 to 24 years) were no different from rates among controls--97 percent and 93 percent, respectively. In the two older quartiles (25 to 41 years and greater than 41 years), 27-year survival rates were significantly less (P less than 0.001)--84 percent and 40 percent, respectively--than in controls (91 and 59 percent). Independent predictors of long-term survival according to multivariate analysis were age at operation (P less than 0.0001) and systolic pressure in the main pulmonary artery before operation (P less than 0.0027). When repair was performed in older patients, late cardiac failure, stroke, and atrial fibrillation were significantly more frequent. CONCLUSIONS Among patients with surgically repaired atrial septal defects, those operated on before the age of 25 have an excellent prognosis, but older patients require careful, regular supervision.

Surgical treatment of neuroendocrine metastases to the liver: : a plea for resection to increase survival

BACKGROUND Hepatic metastases from neuroendocrine tumors have a protracted natural history and are associated with endocrinopathies. Resection is indicated for symptom control. Previous reports have suggested improvement in survival for patients undergoing debulking procedures. STUDY DESIGN The records of all consecutive patients undergoing resection of hepatic metastases from neuroendocrine tumors between 1977 and 1998 were reviewed. Tumors were classified according to histology, endocrine activity, and primary location. Patients lost to followup before 1 year were excluded. Followups were based on outpatient evaluations and were updated by correspondence. The Kaplan-Meier method was used to generate survival and recurrence curves, and the log-rank test was used for comparison. RESULTS A total of 170 patients fulfilled the inclusion criteria, of whom 73 were men. Mean age (+/-SD) was 57 (+/-11.5) years. Carcinoid (n = 120) and nonfunctioning islet cell tumors (n = 18) predominated; the ileum (n = 85) and the pancreas (n = 52) were the most common primary sites. Major hepatectomy (one or more lobes) was performed in 91 patients (54%). The postoperative complication rate was 14%, and two patients died (1.2%). Operation controlled symptoms in 104 of 108 patients, but the recurrence rate at 5 years was 59%. Operation decreased 5-hydroxyindoleacetic acid levels considerably, and no patient experienced carcinoid heart disease postoperatively. Recurrence rate was 84% at 5 years. Overall survival was 61% and 35% at 5 and 10 years, respectively, with no difference between carcinoid and islet cell tumors. CONCLUSIONS Hepatic resection for metastatic neuroendocrine tumors is safe and achieves symptom control in most patients. Debulking extends survival, although recurrence is expected. Hepatic resection is justified by its effects on survival and quality of life.

Revision total hip arthroplasty.

Two hundred and ten hips in 206 patients who had an initial total hip arthroplasty performed at the Mayo Clinic between 1969 and 1978 required revision of the arthroplasty at the Mayo Clinic for reasons other than infection. One hundred and sixty-two of the patients (166 hips) were followed both clinically and roentgenographically for two years or more. One hundred and forty-five (90 per cent) reported that they had improvement after the surgical revision. Complications that occurred with revision included deep sepsis, superficial would infection, dislocation, intraoperative femoral fracture, and postoperative femoral fracture. Roentgenographic analysis showed probable loosening in thirty-three acetabular components (20.1 per cent) and seventy-two femoral components (44 per cent). Symptomatic loosening (moderate to severe pain and probable roentgenographic loosening) was seen in thirty-five patients. Eight patients required a second revision for this reason, and seven others required a second revision for other reasons. Modified Harris hip scores, calculated for 108 hips, showed a good or excellent result in sixty-seven hips (62 per cent), a fair result in twelve (11 per cent), and a poor result in twenty-nine (27 per cent). Using a new Mayo Clinic hip score that incorporates roentgenographic data (which will be described) in the evaluation of 165 revised hips, there was a good or excellent result in eighty-five (52 per cent), a fair result in thirty-two (19 per cent), and a poor result in forty-eight hips (29 per cent). Although 90 per cent of the patients thought that their condition had improved, the high incidence of roentgenographic signs of probable loosening of a component is of serious concern.

Proximal tibial osteotomy. A critical long-term study of eighty-seven cases.

Eighty-seven valgus osteotomies of the tibia were performed in seventy-three patients for osteoarthrosis of the medial compartment of the knee; the median follow-up was ten years (range, three to fourteen years). The data were subjected to univariate and multivariate statistical analysis and to survivorship analysis. For these calculations, the end-point of failure was defined as an arthroplasty of the knee, and additional calculations were performed with the end-point defined as the performance of an arthroplasty or moderate or severe pain in patients who had declined an arthroplasty. None of the many risk factors that were evaluated could be found to be associated with the duration of survival, except for relative weight and angular correction. The median loss of correction after the osteotomy was 1 degree. If, at one year after the operation, the valgus angulation was 8 degrees or more, or if the patients weight was 1.32 times the ideal weight or less, the probability of survival five years thereafter was at least 90 per cent and the probability ten years thereafter was at least 65 per cent. However, when valgus angulation at one year was less than 8 degrees in a patient whose weight was more than 1.32 times the ideal weight, the rate of survival decreased to 38 per cent five years thereafter and to 19 per cent ten years thereafter. There is a considerable risk of failure of a proximal tibial osteotomy if the alignment is not overcorrected to at least 8 degrees of valgus angulation and if the patient is substantially overweight.