Lee S. Woldenberg

MRI of suprascapular neuropathy in a weight lifter.

Suprascapular neuropathy results from abnormal compression of the suprascapular nerve, typically at the suprascapular or spinoglenoid notch. This may be produced by either mass effect such as ganglion cyst or by certain repetitive shoulder motions producing wide scapular excursion (e.g., hyperabduction), which causes traction upon the nerve. Certain sports activities such as weight lifting predispose to this type of neuropathy. The clinical presentation is frequently not specific and the patient may be sent for MR evaluation to rule out rotator cuff tear or other more common shoulder abnormalities. This entity should be suspected if MR images demonstrate selective atrophy of the spinatus muscles with a structurally intact rotator cuff.

Effect of the increase in the height of lumbar disc space on facet joint articulation area in sagittal plane.

Study Design. Computerized tomography (CT) of the lumbar spine cadaveric specimens was used to evaluate the effect of increasing the height of the disc space in the lumbar spine to the facet joint articulation in the sagittal plane. Objective. To show how the facet joint articulation is affected by increasing the height of the disc space in the lumbar spine. Summary of Background Data. The Charité Artificial Disc (DePuy Spine, Inc., Raynham, MA) was successful in relieving low back pain in the majority of patients, yet there was still a significant number of patients who did not obtain pain relief, or their pain even worsened. The etiology of their pain is still not known. To our knowledge, no study has addressed the effect on the facet joints when the disc height is increased. Methods. CT images passing through the center of the L3–S1 facet joints (sagittal plane) were obtained from 15 cadaveric lumbar spine specimens. The articulation overlap of facet joints in sagittal plane from the L3 to S1 was measured. A 1-mm incremental increase to a total 5 mm in disc space height was performed to simulate the changes seen in disc replacement. The change in the facet joint articulation overlap in sagittal plane at normal and each displacement was then measured. There were 5 lumbar spine specimens dissected to validate the technique and standardize the measurements. Mean, percentages, and standard deviation values were calculated for all measured dimensions. Results. No significant difference was found between the measurements on CT and gross specimens (P > 0.05). In 15 specimens, the mean facet joint articulation overlap on the sagittal plane was: 16.29 ± 1.20 mm (left) and 16.22 ± 1.16 (right) at the L3–L4 level; 17.81 ± 1.18 mm (left) and 17.74 ± 1.18 mm (right) at the L4–L5 level; and 18.18 ± 1.18 mm (left) and 18.23 ± 1.15 mm (right) at the L5–S1 level. There is no significant difference between the measured values on left and right sides (P > 0.05). Each 1-mm incremental increase in disc space at the L3–L4 level translated to a decrease in the facet joint articulation overlap in the sagittal plane by 6%, and the mean facet joint space increased 0.4 mm. At the L4–L5 level, the articulation overlap decreased by 6%, and the facet joint space increased 0.5 mm. At the L5–S1 level, the articulation overlap decreased by 4%, and the facet joint space increased 0.7 mm. Conclusions. There is a significant decrease of the facet joint articulation overlap in sagittal plane and an increase in the facet joint space following an increase in the lumbar disc space. The inappropriate increase of the height of disc space will result in facet joint subluxation.

Magnetic resonance imaging in the diagnosis of anterior tibialis muscle herniation

Magnetic resonance imaging (MRI) can be employed to successfully image the fascial compartments of the leg. Herniated muscle tissue and fascial discontinuity can each be unequivocally identified. Both the extent of fascial splitting and the size of the muscle herniation can be demarcated and quantified. MRI is favored over computed tomography because of its superior ability to distinguish soft-tissues structures, making it possible to see both muscle and fascia separately.

How the increase of the cervical disc space height affects the facet joint: an anatomy study.

Study Design. In vitro study on the effect of increasing the height of the cervical disc space on the facet joint. Objectives. To demonstrate how facet joint articulation is affected by increasing the cervical disc space height. Summary of Background Data. A surgeon attempts to increase the disc space and inserts a larger artificial disc than normal in order to keep the intervertebral foramen open and the prosthesis stable. However, it is hypothesized by the current authors that this procedure could have an adverse effect on the facet joints. Methods. Computerized tomography images passing through the disc space and the center of the C4–C7 facet joints (sagittal plane) were obtained from 15 cadaveric cervical spine specimens. A 1-mm incremental increase to a total 5 mm in disc space height was performed to simulate the changes seen in disc replacement. The change in the facet joint articulation overlap and space in the sagittal plane at normal and each displacement was measured. Results. Each 1-mm incremental increase in disc space at C4–C5 translated to a decrease in the facet joint articulation overlap in the sagittal plane by approximately 8%. The mean facet joint space increased approximately 0.8 mm. At the C5–C6 and the C6–C7 levels, the articulation overlap decreased by approximately 7% and the facet joint space increased approximately 0.8 mm. Conclusions. There is a significant decrease of the facet joint articulation overlap in the sagittal plane and an increase in the facet joint space following an increase in the cervical disc space. The inappropriate increase of the disc space height may result in facet joint subluxation and could lead to the accelerated failure of the artificial disc.

Quantitative analysis of changes in cervical intervertebral foramen size with vertebral translation.

Study Design. Simulated translation of the C5 vertebra was performed in 20 embalmed cadaveric cervical spines, and cross-sectional areas of the C4–C5 and C5–C6 intervertebral foramina were measured and compared before and after translation of the C5 vertebra. Objective. To determine the relationship of cross-sectional intervertebral foraminal areas to the degrees of vertebral translation. Summary of Background Data. The common feature of clinical instability and adjacent diseases of the cervical spine is malalignment of the cervical spine (i.e., there is ventral and dorsal translation of vertebral body with respect to the adjacent upper and lower vertebral body, respectively). To our knowledge, no previous study has analyzed the quantitative effect of vertebral translation on the size of the intervertebral foramina. Methods. The cross-sectional areas of the intervertebral foramina at C4–C5 and C5–C6 were measured on computerized tomography. The images were then transferred to the personal computer, where consecutive dorsal translations of C5 vertebrae with a 1-mm increment from 1 to 5-mm displacements were performed using Microsoft paint software (Microsoft, Corp., Redmond, WA). National Institutes of Health (Bethesda, MD) Image J software (V1.33m) was then used to measure the areas of both sides of C4–C5 and C4–C6 foramina at normal and each displacement level in the computer. Results. Following dorsal translation of C5 vertebra, anterolisthesis of C4 relative to C5 and retrolisthesis of C5 relative to C6 was noted. No significant difference was found between the measured values using Aquarius Image software (Microsoft, Corp.) on computerized tomography and National Institutes of Health image J software on the desktop computer (P > 0.05). When compared with normal values, there was an increase in the C4–C5 intervertebral foraminal area (i.e., 6%, 14%, 18%, 21%, and 26% with anterolisthesis of C4 relative to C5 following 1, 2, 3, 4, and 5-mm dorsal translation of the C5 vertebra, respectively). There was a 12% decrease in the C5–C6 intervertebral foraminal area, with each 1-mm incremental retrolisthesis of C5 relative to C6 vertebra. Statistically significant differences were found among residual cross-sectional foraminal areas following different degrees of dorsal translation (P < 0.05). Conclusion. There is a significant increase in size with anterolisthesis and decrease in size with retrolisthesis of upper and lower adjacent vertebral intervertebral foramina, respectively.

Pulmonary vein tumor thrombosis and left atrial extension in lung carcinoma

A case of lung carcinoma extending into left atrium through a pulmonary vein and mimicking left atrial myxoma is presented. The localized enlargement of a pulmonary vein is seen as a possible CT sign of pulmonary vein tumor thrombosis. Computed tomography (CT) and echocardiography are complementary in the correct diagnosis of this condition.

Assessment of Collicular Fractures of the Medial Malleous

Collicular fractures of the medial malleolus have been described in literature as early as 1950 by Bonnin 1 and then by Pankovich 9 in 1979, yet have been given relatively little attention in orthopaedic and radiologic literature. A precise knowledge of the anatomy of the deltoid ligament, and anterior and posterior colliculi in relation to obtained radiographs is important in the determination of whether a fracture is considered to be stable or unstable, and thus bears an impact on its treatment. The intent of this discussion is to review the structures which comprise the medial malleolus and the assessment of their involvement in acute injury.

Recurrent sinus pericranii in a 14-year-old boy

A case of symptomatic and recurrent sinus pericranii in a 14-year-old boy is presented. A blood-filled cyst was diagnosed after head trauma. The sinus pericranii was surgically removed. One year later the patient presented with blurred vision, headaches, and recurrence at a different site in the skull.

POST-TRAUMATIC SYNOVITIS PRESENTING AS A MASS IN THE SUPRAPATELLAR BURSA OF THE KNEE MRI APPEARANCE

A lobulated mass in the suprapatellar bursa of the knee is presented with MRI findings simulating the features of focal pigmented villonodular synovitis (PVS). Microscopic examination demonstrated a nonspecific, inflammatory mass of hypertrophied synovium. The MRI features of various forms of synovitis are reviewed from recent literature and differential considerations of a suprapatellar, intrabursal mass are discussed.

Magnetic resonance imaging of hepatic adenoma

A case of hepatic adenoma imaged by magnetic resonance imaging (MRI) as well as with angiography, computed tomography, and radionuclide imaging is presented. Pathological correlation is also presented. Review of the literature of MRI of hepatic adenoma and related tumors is discussed.