Biomedical subjects

J F Orwin

Publications and source records attributed to J F Orwin.

At least 19 recordsLinked to original sources

PubMed2001

Angled oblique sagittal MR imaging of rotator cuff tears: comparison with standard oblique sagittal images.

OBJECTIVE: To compare the accuracy for diagnosing rotator cuff tears of oblique coronal images supplemented with standard oblique sagittal images versus thinner-section angled oblique sagittal images. DESIGN AND PATIENTS: The study included 75 consecutive patients who had a shoulder MR scan followed by arthroscopy. MR images included oblique coronal, oblique sagittal (4 mm thick, 1 mm interslice gap), and angled oblique sagittal (3 mm/0.2 mm) images perpendicular to the lateral cuff. A musculoskeletal staff radiologist and fellow separately evaluated the cuff for tears on the oblique coronal images supplemented with either the oblique sagittal or the angled sagittal images. RESULTS: For distinguishing a cuff tear from no tear, the staff radiologist had an accuracy of 0.76 (95% confidence interval: 0.67, 0.85) with the standard sagittal set, and 0.88 (0.80, 0.95) with the angled set (P=0.04). There was a nonsignificant improvement in accuracy for the fellow, calculated as 0.73 (0.63, 0.83) on the standard sagittal set and 0.76 (0.67, 0.85) on the angled set. Both readers also improved their diagnostic accuracy for partial-thickness tears with the angled set, although the improvement was statistically significant only for the staff radiologist. CONCLUSION: There is a slight improvement in accuracy for diagnosing rotator cuff tears, particularly partial-thickness tears, for the more experienced radiologist using thinner-section angled oblique sagittal images. These images may be useful as a supplemental sequence in patients where it is important to identify partial-thickness tears accurately.

Adult↗

PubMed2000

The biologic response to laser thermal modification in an in vivo sheep model.

The purpose of this study was to evaluate the effect of nonablative laser energy on mechanical, histologic, ultrastructural, and biochemical properties of joint capsular tissue in an in vivo sheep model. Femoropatellar joint capsule was treated with the holmium:yttrium-aluminum-garnet laser via an arthroscope, and tissues were harvested immediately after surgery, or at 3, 7, 14, 30, 60, 90, and 180 days after surgery (n = 8/group). Laser treatment caused significant decreases in tissue stiffness from 0 to 7 days after surgery, then stiffness gradually increased after 14 days. Tissue strength was lowest 3 days after laser treatment. Histologic examination revealed immediate collagen hyalinization and cell necrosis, followed by active cellular response characterized by extensive fibroblast migration and capillary sprouting. Tissue appeared to be normal histologically 60 days after surgery; however, collagen fibrils remained uniformly small. This study showed an active tissue response secondary to thermal modification with concomitant recovery of mechanical properties by 30 days after surgery. Whether the shrinkage or joint stability was maintained with time remains to be evaluated. To clarify the advantages and disadvantages of this technique, a carefully controlled clinical trial with long term followup should be performed.

Animals↗

PubMed2000

Superior labrum anterior-posterior (SLAP) tears: evaluation of three MR signs on T2-weighted images.

PURPOSE: To compare the sensitivity and specificity of three magnetic resonance (MR) imaging signs for the diagnosis of superior labrum anterior-posterior (SLAP) tears. MATERIALS AND METHODS: The study involved 23 consecutive patients with a type 2, 3, or 4 SLAP tear at arthroscopy and 31 age-matched control patients with an arthroscopically normal or type 1 SLAP lesion. The superior labrum was evaluated on MR images for high signal intensity extending to the articular surface in the posterior third of the labrum, an irregular or laterally curved area of high signal intensity, or two high-signal-intensity lines. RESULTS: The sensitivity, specificity, and accuracy of posterior high signal intensity for a type 2, 3, or 4 SLAP tear were 48%, 94%, and 74%, respectively, for observer 1 and 61%, 81%, and 72%, respectively, for observer 2. For laterally curved area of high signal intensity, these values were 65%, 84%, and 76%, respectively, and 56%, 84%, and 72%, respectively. For two high-signal-intensity lines, these values were 17%, 94%, and 61%, respectively, and 13%, 94%, and 59%, respectively. For the presence of either posterior or laterally curved high signal intensity, the sensitivity was 65% for both observers, whereas the specificity was 84% for observer 1 and 74% for observer 2. The kappa values for interobserver agreement were 0.60 for posterior high signal intensity and 0.58 for laterally curved high signal intensity. CONCLUSION: Laterally curved and posterior high signal intensities are specific signs for distinguishing a SLAP tear from a normal-variant superior sublabral recess.

Adolescent↗

PubMed1999

Fat-suppressed fast spin-echo mid-TE (TE[effective]=34) MR images: comparison with fast spin-echo T2-weighted images for the diagnosis of tears and anatomic variants of the glenoid labrum.

OBJECTIVE: To compare the sensitivity, specificity, and accuracy of fat-suppressed fast spin-echo (FSE) mid-TE (TE[effective]=34) images with fat-suppressed FSE T2-weighted images for the diagnosis of labral abnormalities. DESIGN AND PATIENTS: The study included 27 consecutive patients who had axial fat-suppressed FSE T2-weighted and fat-suppressed FSE mid-TE MR images, and had labral abnormalities diagnosed at arthroscopy. The acquisition time was about 5 min for each sequence, but the mid-TE sequence allowed a higher spatial resolution than the T2-weighted images (256x256 versus 256x192). Twenty-eight age-matched patients with arthroscopically normal labra were included as a control group. The labrum was graded on the MR images as normal or abnormal separately by two musculoskeletal radiologists who were masked to the history and arthroscopic results. The surgical findings were used as the gold standard for calculating the sensitivity, specificity, and accuracy for interpreting the correct location of a labral abnormality. The sensitivity, specificity, and accuracy for the two sequences were compared with a McNemar test, and significance defined as P<0.05. RESULTS: For observer 1, the sensitivity for labral abnormalities was 0.59 on the T2-weighted images, and 0.78 on the mid-TE images (P=0.12). The specificity was 0.54 for the T2-weighted, and 0.64 for the mid-TE images (P=0.51). The accuracy was 0.56 for the T2-weighted, and 0.71 for the mid- TE images (P=0.08). For observer 2, the sensitivity/specificity/accuracy was 0.67/0.93/0.80 for the T2-weighted, and 0.70/0.86/0.78 for the mid-TE images (all P>0.5). CONCLUSION: In this small study there is no statistically significant difference for demonstrating labral abnormalities between FSE T2-weighted images, and higher-resolution fat-suppressed FSE mid-TE (TE[effective]=34) images obtained with a similar acquisition time. Although there was a general trend toward higher sensitivity and accuracy with the mid-TE sequence, particularly for one of the two observers, a larger study is needed to determine whether this is the preferred single axial pulse sequence for conventional MR imaging of the labrum.

Adolescent↗

PubMed1998

Anterior versus posterior, and rim-rent rotator cuff tears: prevalence and MR sensitivity.

PURPOSE: To determine the relative distribution of the locations of rotator cuff tears, and the sensitivity of anterior versus posterior tears on MR images. PATIENTS AND METHODS: We identified 110 consecutive patients who had a shoulder MR and either a partial-thickness or a small full-thickness rotator cuff tear diagnosed at arthroscopy. From the arthroscopy videotapes, we classified the tears as centered in the anterior or posterior half of the cuff, and as either in the critical zone or adjacent to the bony insertion. The original MR interpretation was compared with the arthroscopic findings. MR sensitivity and patient age were compared between patients with tears in the anterior and posterior halves of the cuff. In addition, in patients with partial tears less than 2 cm in diameter, an age comparison between those with tears in the critical zone and those with articular surface tears adjacent to the bony insertion (rim-rent tear) was performed. RESULTS: The tear was centered in the anterior half of the rotator cuff in 79% of the patients younger than 36 years old, and in 89% of the patients 36 years old and over. The average age of the patients with tears in the anterior half (44 years) was not significantly different from the average age of those with posterior tears (40 years) (P = 0.23). The sensitivity of MR for anterior tears was 0.69, and for posterior tears it was 0.56 (P = 0.17). The average age of the 9 patients with rim-rent tears was 31 years, while that of the 28 patients with similarly-sized partial tears not involving the insertion was 40 years old (P = 0.048). Five of the nine rim-rent tears (0.56) were interpreted correctly on the original MR report; two of the other tears were misinterpreted as intratendinous fluid but were diagnosable in retrospect. CONCLUSION: Even in patients less than 36 years old, most partial and small full-thickness rotator cuff tears are centered in the anterior half of the supraspinatus. Although our figure for MR sensitivity for these tears is lower than in recent articles, we found no significant difference between the sensitivity of MR for diagnosing posterior tears versus tears in the anterior half of the supraspinatus tendon. Rim-rent tears can be mistaken for intratendinous signal, and should be carefully looked for in younger patients with shoulder pain.

Adolescent↗

PubMed1998

Rotator cuff tendinopathy and subacromial impingement syndrome.

Subacromial impingement syndrome is one of the most frequently seen causes of shoulder pain. The symptoms are often vague and may be difficult to differentiate from other shoulder problems. The purpose of this paper is to provide the clinician with a more thorough understanding of this entity by reviewing the pertinent anatomy and underlying etiology. Suggestions are made to aid in establishing the diagnosis, and treatment recommendations are proposed.

Adrenal Cortex Hormones↗

PubMed1997

Anteroinferior tears of the glenoid labrum: fat-suppressed fast spin-echo T2 versus gradient-recalled echo MR images.

OBJECTIVE: To compare fat-suppressed fast spin-echo (FSE) T2-weighted images with gradient-recalled echo (GRE) T2*-weighted images in the evaluation of anteroinferior labral tears. DESIGN: MR images were retrospectively reviewed by two radiologists masked to the history and arthroscopic findings. They separately interpreted the anteroinferior labrum as torn or intact, first on one pulse sequence and then, 4 weeks later, on the other sequence. The MR interpretations were correlated with the arthroscopic findings. PATIENTS: Nine patients with anteroinferior labral tears, and nine similarly-aged patients with normal, labra were studied. RESULTS AND CONCLUSIONS: Observer 1 had a sensitivity of 0.56 on the GRE images and 0.67 on the FSE images (P > 0.5), with a specificity of 1.0 for both sequences. Observer 2 had a sensitivity of 0.78 and a specificity of 0.89 for both sequences. In this small study there is no significant difference between GRE and fat-suppressed FSE images in their ability to diagnose anteroinferior labral tears. When evaluating the labrum with conventional MRI, axial fat-suppressed FSE T2-weighted images can be used in place of GRE images without a loss of accuracy.

Adolescent↗

PubMed1996

Evaluation of post-exercise magnetic resonance images of the rotator cuff.

OBJECTIVE: To examine the effect of strenuous exercise on the magnetic resonance imaging (MRI) characteristics of the rotator cuff tendon. A second objective was to define an optimal time to image the rotator cuff and possibly eliminate exercise-induced false positives. DESIGN AND PATIENTS: Five male subjects from 24 to 38 years old with normal rotator cuffs by history, physical examination, and screening MRI underwent a rotator cuff exercise session on the Biodex System 2 (Biodex, Shirley, New York). The exercise sessions were followed by sequential MRI scans of the exercised shoulder. These were performed immediately and at 8 h and 24 h after exercise. RESULTS AND CONCLUSIONS: The rotator cuff tendon and subacromial-subdeltoid bursal signal remained unchanged from the pre-exercise through the 24-h post-exercise scans. The rotator cuff muscle signal was increased in five of five subjects on the immediate post-exercise fat-suppressed T2-weighted images. This signal returned to baseline by the 8-h scan. Positive findings of rotator cuff pathology on MRI after strenuous athletic activity should not be discounted as normal exercise-induced changes. Also, diagnostic MRI scanning may take place after a practice session without an increased risk of false positives.

Adult↗

PubMed1996

Open inferior glenohumeral dislocation.

An open inferior glenohumeral dislocation or luxatio erecta humeri is a rare type of shoulder dislocation, with only two cases reported in the literature. Presented is the case of a 36-year-old farmer who sustained an open inferior glenohumeral dislocation in a farm equipment accident. The humeral head penetrated the skin inferior to the pectoralis major muscle, an avulsion fracture of the greater tuberosity was present, and the subscapular tendon was ruptured near its insertion into the lesser tuberosity. At follow-up 18 months after injury, the restricted range of motion of the shoulder remained despite treatment attempts, including manipulation under anesthesia with arthroscopic debridement of the shoulder; however, no evidence of avascular necrosis of the humeral head was found.

Adult↗

PubMed1996

Anterosuperior labral variants of the shoulder: appearance on gradient-recalled-echo and fast spin-echo MR images.

PURPOSE: To characterize the magnetic resonance (MR) imaging appearance of two anterosuperior labral variants, the sublabral foramen (SLF) and the Buford complex. MATERIALS AND METHODS: The axial gradient-recalled-echo (GRE) MR images and the fat-suppressed, T2-weighted, fast spin-echo (SE) images were reviewed in 19 patients with arthroscopically proved SLF and 11 patients with a Buford complex. The anterosuperior labrum was graded as normal, detached, or absent on the images. RESULTS: For the patients with an SLF, the anterosuperior labrum was graded as detached in all patients who underwent fast SE imaging but in only 43% of patients who underwent GRE imaging. For the patients with a Buford complex, the anterosuperior labrum was graded as absent in only 30% of patients who underwent GRE imaging and in none of the patients who underwent fast SE imaging. CONCLUSION: Isolated MR abnormalities of the anterosuperior labrum may represent either of the two asymptomatic labral variants.

Adult↗

PubMed1995

Effect of field of view on MR diagnosis of rotator cuff tears.

PURPOSE: To determine the effect of decreasing the field of view (FOV) on the accuracy of MR for diagnosing rotator cuff tears. MATERIAL AND METHODS: One hundred shoulder MR scans with surgical correlation were evaluated for the presence or absence of a cuff tear. The sensitivity and specificity of MR relative to the surgical results were determined for the 59 patients scanned with a 24-cm FOV, and the 41 patients scanned with an 18-cm FOV. All other imaging parameters including acquisition time were identical. The sensitivity and specificity of the two groups were compared using a t-test. RESULTS: The specificity of MR for diagnosing a rotator cuff tear improved from 0.65 for the 24-cm FOV group to 0.89 for the 18-cm FOV group (P = 0.04). The sensitivity changed from 0.91 to 0.96 (P = 0.25). CONCLUSION: Reducing the FOV from 24 cm to 18 cm results in a statistically significant improvement in specificity of MR for diagnosing rotator cuff tears.

Adult↗

PubMed1995

Suprascapular nerve entrapment by ganglion cysts: a report of six cases with arthroscopic findings and review of the literature.

Suprascapular nerve entrapment by a ganglion cyst can produce pain and shoulder dysfunction. We report six cases with the associated arthroscopic intraarticular findings of a posterior capsulolabral injury (only the second such description) and review the literature. Based on the current literature and our experience, we document our treatment algorithm for suprascapular nerve entrapment secondary to a ganglion cyst. We believe it is necessary to evaluate and treat the intraarticular pathology as well as the ganglion cyst/nerve entrapment to successfully manage these patients.

Adult↗

PubMed1995

MR diagnosis of labral tears of the shoulder: value of T2*-weighted gradient-recalled echo images made in external rotation.

OBJECTIVE: Because several studies have shown that conventional MR imaging can fail to diagnose a significant percentage of labral tears, some authors have proposed obtaining T2*-weighted gradient-recalled echo images with the humerus in external rotation. The purpose of our study was to determine whether the diagnostic accuracy of detecting anteroinferior labral tears by MR imaging would be improved by adding a T2*-weighted gradient-recalled echo sequence with the humerus in external rotation. MATERIALS AND METHODS: The study included 24 patients for whom axial MR images of the shoulder were obtained with the humerus in both the neutral position and external rotation. Two observers interpreted the images made in the neutral position and then noted any change in their interpretations after viewing findings on the external-rotation images. MR results were correlated with surgical findings. At surgery, 14 anteroinferior labra were found to be torn and 10 were found to be intact. RESULTS: Both observers identified one patient for whom a surgically proved labral tear was seen only on the external-rotation images. The sensitivity increased from 0.43 to 0.50 (p = .35) for observer 1 and from 0.36 to 0.43 (p = .35) for observer 2. The specificity of 0.90 for both observers remained unchanged. The accuracy improved from 0.62 to 0.67 for observer 1 and from 0.55 to 0.62 for observer 2. CONCLUSION: The addition of external-rotation T2*-weighted gradient-recalled echo images to the MR examination for tears of the anteroinferior labrum leads to a small but statistically insignificant increase in diagnostic sensitivity. We conclude that the small increase in sensitivity does not justify the routine use of this sequence.

Adolescent↗

PubMed1995

Acromial angle on radiographs of the shoulder: correlation with the impingement syndrome and rotator cuff tears.

OBJECTIVE: This study was undertaken to determine the reproducibility of measurements of an acromial angle on radiographs and to correlate those measurements with the presence of the impingement syndrome and rotator cuff tears. MATERIALS AND METHODS: Ninety-nine shoulders in 95 patients who had an arch radiograph and had undergone shoulder arthroscopy were included in this retrospective study. The acromial angle was measured on the arch view of the shoulder independently by three observers who were blinded to the name, history, and arthroscopic results. The angle was measured at the intersection of lines drawn along the inferior cortex of the anterior and posterior portions of the acromion. Interobserver variability was determined by the intercorrelation coefficient (a test of reproducibility of quantitative measurements). The average of the three measurements for each patient was correlated with the preoperative diagnosis and the arthroscopic findings. RESULTS: A correlation was found between increasing severity of cuff disease as determined on arthroscopy and increasing acromial angle (p < .01). In 67 patients (70 shoulders) with impingement, patients with a full-thickness tear (29%) accounted for 43% of those with an angle of 30 degrees or greater. The average acromial angle for patients with impingement was greater than that for either patients with instability or patients with trauma (p < .05 for both). An angle of 25 degrees or greater was measured in 63% of patients with impingement but in only 18% of those with instability. The average acromial angle in patients with impingement and an intact rotator cuff was also greater than the average angle in patients with instability (p = .001). The interobserver variability had an intercorrelation coefficient of 0.90. CONCLUSION: The acromial angle is an objective and fairly reproducible measure of anterior acromial shape. The angle is useful in identifying patients with a greater likelihood of having a rotator cuff tear and in distinguishing patients with primary impingement from those with instability.

Acromion↗

PubMed1994

Diagnosis of partial and complete rotator cuff tears using combined gradient echo and spin echo imaging.

Most magnetic resonance (MR) studies evaluating the rotator cuff for tears have used T2-weighted imaging in the coronal oblique and sagittal oblique planes. T2*-weighted gradient echo imaging, however, has advantages over spin echo imaging, including contiguous slices without cross-talk, high contrast around the cuff, and intrinsically shorter imaging times which can be used to increase the number of signals averaged and thus improve the signal-to-noise ratio. We reviewed the shoulder MR scans of 87 consecutive patients who underwent both a MR scan and a shoulder arthroscopy during which the size of tears, if present, was graded. The reviewers were blinded as to the history and arthroscopic results. The MR scans included oblique coronal T2*-weighted gradient echo and oblique sagittal T2-weighted spin echo images. MR cuff grades were correlated with arthroscopic findings. For complete tears, the sensitivity of MR was 0.91 and the specificity 0.95. For partial tears, the sensitivity was 0.74 and the specificity 0.87. This accuracy is similar to two-plane T2-weighted imaging as previously reported in the literature. There was a statistically significant correlation (p < 0.0005) between the cuff grade as determined by MR and the arthroscopic findings.

Adult↗

PubMed1991

Use of the uncemented bipolar endoprosthesis for the treatment of steroid-induced osteonecrosis of the hip in renal transplantation patients.

Osteonecrosis of the hip is a well known complication in renal transplantation patients who are treated with corticosteroids for immunosuppression. In a consecutive series of 10 patients with osteonecrosis of the hip, 16 primary uncemented bipolar endoprostheses were inserted between April 1984, and February 1986. The average follow-up period after surgery was 40 months, (range, 24-48 months). All patients developed osteonecrosis of their hips and were operated on within 2 years of their renal transplant. At the time of surgery, all patients were still taking corticosteroids as well as other immunosuppressants. The average age at surgery was 34.6 years (range, 21-48 years). All hips were classified as stage 3 or 4 before operation. The average Harris score at follow-up examination was 94.2 (range, 74-101), with 13 hips rated excellent, 1 hip rated good, and 1 hip rated fair. One patient's hip prosthesis was removed after 17 months secondary to a septic arthritis. This was the only major complication in this series. Pain was improved in all patients. However, postoperative limp and abductor weakness still presented a significant problem. An extensive radiographic evaluation was made on all hips. Eleven observations and measurements were made using radiographs of the pelvis and hip. Vertical subsidence was present in 33% of the hips and averaged 2.2 mm (range, 1-4 mm). No significant radiographic loosening was evident in any hip. Acetabular protrusio was evaluated in all patients, and was found to be less than 4 mm in either the superior or axial direction. Heterotopic ossification was present in 80% of hips, but resulted in loss of motion in only one hip.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗

PubMed1989

Resection of heterotopic ossification in patients with spinal cord injuries.

Nineteen spinal cord injury (SCI) patients were treated with resection of heterotopic ossification (HO) in 24 hips. The average follow-up period after surgery was 6.1 years. The mean time to surgery after injury was 50.6 months. The indication for surgery in all patients was improvement in hip motion to allow sitting. The average preoperative motion in flexion and extension was 11.5 degrees. The average intraoperative motion was 82.7 degrees. The average postoperative motion at the follow-up evaluation was 35.2 degrees. Fourteen of 19 patients (74%) had sufficient motion at the follow-up evaluation for sitting. Unlimited sitting tolerance was achieved in seven patients (37%), and seven patients (37%) had improved sitting posture with some time limitations. The average arc of motion in those patients able to sit at the follow-up evaluation was 41.5 degrees. Normal bone scans, alkaline phosphatase levels, and the mature roentgenographic appearance of HO were unreliable predictors of recurrence. The preoperative range of motion was the best predictor of improved postoperative range of motion since patients with retained motion did better than those with severe ankylosis. All six hips with severe recurrence had 0 degree of preoperative motion. The average degree of preoperative motion for all remaining hips was 15.3 degrees. The best predictor of recurrence was the roentgenographic grade of HO. Nineteen of 22 hips (86%) with a mild to severe recurrence had large amounts of bone preoperatively (Grades 3-5). Complications excluding recurrence occurred in 19 of 24 hips (79%) and included superficial wound infections in nine of 24 hips (38%) and deep persistent infections (osteomyelitis) in eight of 24 hips (33%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

Acromial structure and tears of the rotator cuff.

Rotator cuff lesions have been related to the structure of the acromion. We report a clinical review of 56 shoulders and the analysis of their acromial structure as seen on the radiographic arch (outlet) view and magnetic resonance imaging. The shoulders were classified as acromial type I (flat), type II (curved), or type III (hooked). On plain radiographs 89% of type III acromions had tearing of the rotator cuff (p < 0.001). The association between acromial type as determined on magnetic resonance imaging and the presence of rotator cuff tearing was less significant. Magnetic resonance imaging offered no additional benefit over plain radiographs for determining acromial type. In addition, a method of quantitating acromial structure (the "acromial angle") was devised. This angle showed a significant association with acromial types (p < 0.0001) seen on plain radiographs and had good interobserver reproducibility (coefficient of variation, 0.1). With this measurement system a type I acromion had an acromial angle of 0 degrees to 12 degrees; a type II acromion, 13 degrees to 27 degrees; and a type III acromion, greater than 27 degrees.

Acromion↗