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Biomedical subjects

L J Grobler

Publications and source records attributed to L J Grobler.

25 records · Page 2Linked to original sources
PubMed1993

Paraspinal mapping: quantified needle electromyography in lumbar radiculopathy.

In the diagnosis of low back pain, the presence of a high percentage of false positive findings on radiologic imaging studies has lead to a more definitive role for electrodiagnosis as a confirmatory test. The paraspinal muscles are a crucial part of the electrodiagnostic examination for radiculopathy. To date, no technique for paraspinal evaluation has been validated. Based on previously documented anatomical techniques, we have designed a method of paraspinal examination termed "paraspinal mapping" (PM). Electromyographic (EMG) needles are placed in five carefully chosen locations and inserted in multiple directions. Individual scores for these insertions are added to determine a total PM sensitivity score. The first 50 studies using PM were compared to peripheral EMG, imaging studies, and pain drawings. Results indicate that the technique is easy to perform. Sensitivity scores relate well with these tests. In this limited and uncontrolled population, PM had higher sensitivity for abnormalities than either peripheral EMG or imaging studies. Because of the anatomical validity of PM, future studies may show it to be useful in localizing the level of radiculopathy independently from peripheral EMG, and to support clinical findings and imaging studies.

Electromyography↗
PubMed1993

Etiology of spondylolisthesis. Assessment of the role played by lumbar facet joint morphology.

This study examined the role of facet joint morphology in the etiology of both degenerative spondylolisthesis and isthmic spondylolysis. To this end, the axial facet joint morphology of the lower lumbar spine in a normal population and in populations of patients with spinal stenosis or degenerative spondylolisthesis at L4-5 and in patients with isthmic spondylolysis at the L5 level were characterized. Computed tomographic scans were digitized, defining the axial morphology of the normal facet joint at five stations from proximal to distal within the joint. Assessments were made of facet joint orientation, transverse articular dimension, depth of the articular surface, and shape of the articular surface at levels L3-4, L4-5, and L5-S1. There was a gradually more coronal orientation from proximal to distal among the stations at each level, and a maximal transverse articular dimension at the level of the superior endplate of the caudad vertebra. Minimal error in the recording process at this level. In addition to the maximal joint dimension, made this level the most representative of the overall morphology and most useful for further studies. At the L4-5 level, a significantly more sagittal facet orientation was found in the degenerative spondylolisthesis group when compared to both the normal population and spinal stenosis groups (P < 0.01). At L5-S1, the only significant morphologic difference between the normal population and the patients with isthmic spondylolysis was reduced transverse articular dimension. These results support the hypothesis that patients developing degenerative spondylolisthesis are predisposed to this by a developmental sagittal orientation of the L4-5 facet joints.

Adult↗
PubMed1991

Hole preparation techniques for transpedicle screws. Effect on pull-out strength from human cadaveric vertebrae.

In each of eight thoracolumbar human cadaveric vertebrae, a hole was made through one pedicle into the vertebral body with a drill bit and through the contralateral pedicle with a probe. Identical metal screws were implanted into the holes to equal depths, and maximum pull-out force was determined for each screw. Using a paired Student t test, no significant difference (P = 0.87) was found in pull-out strength between the screws implanted into drilled holes and those implanted into probed holes. In fact, the average pull-out strengths for the two groups differed by less than 2%. The pedicular cortex was broken through during hole preparation in 5 of the 16 pedicles: 3 as a result of drilling and 2 secondary to probing. The average pull-out strength of the screws in these five pedicles was 11.0% less than the average pull-out strength of the screws implanted into the contralateral intact pedicles. Although this does not represent a statistically significant difference (P = 0.15), it suggests that damaging the pedicular cortex may weaken pedicle screw fixation.

Aged↗
PubMed1985

[Scoliosis studies with low-dose X-rays].

A modification of the Oxford technique for the radiological examination of scoliotic curvatures in school-children has been devised. Satisfactory image quality is achieved in this way and the radiation dose to patients, despite examinations every 3 months, is only a fraction of the maximum permissible level for radiation workers. The method is simple. Conventional X-ray equipment can be employed.

Humans↗
PubMedDate not supplied

Intervertebral disc herniation in the adolescent.

Twenty-nine patients between 14 and 20 years of age underwent surgical treatment for intervertebral disc herniation over a 10-year period. Trauma was a significant factor in 59%. Back pain was a major complaint in all cases, and all but one had significant sciatic distress. Typical painful, restricted forward flexion was found in 22 cases. All patients had definite signs of nerve root tension. Nerve compression signs were present in 41%. Myelography was done in all cases, and discography was performed on 22 patients to aid in diagnosis and planning of definitive treatment. Twenty-three patients were followed over an average of 5.3 years. Excellent or good results were found in 89%. One patient required a further surgical procedure. Analyzing 12 procedures performed at the L5-S1 level demonstrated excellent results in all patients undergoing lumbosacral fusion combined with discotomy at this level in the presence of a normal L4-5 discogram.

Adolescent↗