Subchondral marrow changes after laser diskectomy in the lumbar spine: MR imaging findings and clinical correlation.

OBJECTIVE: We examined MR imaging findings and determined the clinical significance of subchondral bone marrow changes in the lumbar spine of holdium:yttrium aluminum garnet laser diskectomy patients. MATERIALS AND METHODS: We retrospectively reviewed the pre- and postoperative MR images of 109 patients with recurrent radiculopathy, lower back pain, or both 1 year after laser diskectomy of 178 disks. From this group of patients, MR images were also obtained in 11 patients with subchondral marrow changes 5-7 years after surgery. These patients were interviewed regarding residual lower back pain. Thirteen asymptomatic laser diskectomy patients also underwent follow-up MR imaging within 1 year of surgery. RESULTS: After surgery, subchondral marrow abnormalities were identified in 41 of 109 laser diskectomy patients. The remaining 68 patients had no postoperative subchondral bone marrow changes. Postoperative subchondral marrow changes were not associated with inflammation of the adjacent disk space and did not affect surgical outcome. Bone marrow changes decreased in size in the 11 patients examined 5-7 years after laser diskectomy, and eight of these patients described their lower back pain as improved. In 13 asymptomatic laser diskectomy patients, one new subchondral marrow abnormality was identified. CONCLUSION: Subchondral marrow abnormalities may occur in the vertebral end plates after holmium:yttrium aluminum garnet laser diskectomy. However, these changes probably do not affect surgical outcomes and appear to resolve over time.

Tendinosis and tears of gluteus medius and minimus muscles as a cause of hip pain: MR imaging findings.

OBJECTIVE: This study was conducted to determine the prevalence of tendinosis and tears of gluteus medius and minimus muscles in patients presenting with buttock, lateral hip, or groin pain; describe the MR imaging findings; and discuss their probable relationship to the greater trochanteric pain syndrome. SUBJECTS AND METHODS: Two hundred fifty MR imaging examinations of the hip were performed for the evaluation of buttock, lateral hip, or groin pain. The findings were reviewed for changes in the morphology or signal intensity of gluteus medius and minimus muscles and tendons and for any peritendinous abnormality including distention of regional bursae. RESULTS: Thirty-five studies met our criterion of showing either tendinosis or tears of gluteus medius and minimus muscles as the primary positive finding. Eight patients had complete retracted tears of the gluteus medius, and 14 patients had partial tears; in 13 patients, MR findings were consistent with tendinosis. The gluteus minimus muscle was also involved in 10 patients. MR imaging findings were the same as those described for tears and tendinosis of other regions of the body. Surgical proof of a tendon tear was obtained in six patients. CONCLUSION: Tendinopathy of the hip abductors and gluteus medius and minimus muscles was a common finding on MR imaging in our patients with buttock, lateral hip, or groin pain. Tendinopathy is probably a frequent cause of the greater trochanteric pain syndrome, a common regional pain syndrome that can mimic other important conditions causing hip pain including avascular necrosis and stress fracture. Moreover, it is likely that trochanteric bursitis is associated with tendinopathy.

Using abduction and external rotation of the shoulder to increase the sensitivity of MR arthrography in revealing tears of the anterior glenoid labrum.

OBJECTIVE: The purpose of this study was to compare oblique axial MR arthrograms obtained with the patient's shoulder in abduction and external rotation (ABER) position with conventional axial MR arthrograms obtained with the patient's arm in neutral position and the shoulder not rotated in revealing tears of the anterior glenoid labrum (AGL). SUBJECTS AND METHODS: MR arthrography of the shoulder that included an additional oblique axial imaging sequence with the patient in the ABER position was performed in 256 patients. Assessment of AGL integrity with patients in both conventional axial and ABER positions was made before surgery. These assessments were compared with the surgical findings. RESULTS: Of the 92 patients who underwent surgery, AGL tears were found in 27. Conventional axial MR arthrograms revealed 13 tears (sensitivity, 48%; specificity, 91%). A separate review of MR arthrograms obtained with patients in the ABER position revealed 24 tears (sensitivity, 89%; specificity, 95%). Reviewed together, axial MR arthrograms and MR arthrograms obtained with patients in the ABER position revealed 26 tears (sensitivity, 96%; specificity, 97%). CONCLUSION: Oblique axial MR arthrograms obtained with the patient's shoulder in the ABER position were significantly more sensitive in revealing AGL tears (p = .005) than were conventional axial MR arthrograms obtained with the patient's aim in a neutral position and the shoulder not rotated.

Acute myositis ossificans.

We have described the pre- and postgadolinium MR appearance in one case of acute myositis ossificans. The unenhanced sequences can be helpful in excluding malignancy, particularly when viewed serially. While use of gadolinium allowed primary sarcoma to be ruled out in this case, it was not useful in the exclusion of early abscess formation or necrotic metastasis.

Varicoceles: postoperative prevalence--a prospective study with color Doppler US.

To define the ultrasound (US) prevalence of varicoceles after surgical repair, 28 postoperative patients underwent color Doppler US. A group of 26 control subjects also underwent color Doppler US to establish the prevalence of varicoceles in the healthy population. Eighteen of 28 (64%) patients who underwent color Doppler US scanning 16.4 months, on average, after varicocele repair had evidence of a varicocele, a number similar to that reported in other series for infertile men before surgery. Dominant veins in the postoperative patients were larger (P < .01) than those in the control subjects. Postoperative improvements in sperm parameters and conception rate in our subjects were 58% and 43%, respectively, consistent with findings reported in the literature. The prevalence of varicoceles detected at color Doppler US in our healthy population was 42% (11 of 26). Physical examination after surgery failed to show a varicocele in 20 of 22 (91%) patients examined. The discrepancy between sperm parameters and the results of color Doppler US and physical examination raises questions about the utility of US as a means of evaluation in the postvaricocelectomy patient.

Improved use of arterial blood gas analysis in suspected pulmonary embolism.

Since hypoxemia is not known to be a sensitive indicator of acute pulmonary embolism, we performed a retrospective study to determine whether an increased P(A-a)O2 gradient or hypocapnia improved the sensitivity of blood gas analysis in acute embolism. The study group consisted of 78 patients with angiographically documented emboli who had blood gas samples obtained while breathing room air. None had a prior history of cardiopulmonary disease. Hypoxemia was present in 59 patients (76 percent), hypoxemia or hypocapnia in 73 patients (93 percent), an increased P(A-a)O2 gradient in 74 patients (95 percent), and an increased P(A-a)O2 gradient or hypocapnia in 77 patients (98 percent). Only one patient with acute embolism showed a normal P(A-a)O2 gradient and normal PaCO2 breathing room air. These results suggest that a normal P(A-a)O2 gradient and a normal PaCO2 obtained in a patient during room air breathing can be used as evidence against the presence of pulmonary emboli.