Biomedical subjects

E H Widell

Publications and source records attributed to E H Widell.

9 recordsLinked to original sources

PubMed1989

Anatomic analysis of pedicle cortical and cancellous diameter as related to screw size.

The effective thoracic and lumbar pedicle diameter as related to screw size for that pedicle was studied in six fresh-frozen human cadaver spines. Measurements of the pedicle were obtained before screw insertion using axial and coronal reformatted computed tomographic (CT) images, as well as graduated sounding of the pedicle. After sequentially loading each pedicle with increasingly larger screws, measurements were taken of the outer cortical diameters. Plastic deformation of the pedicle preceded pedicle fracture or cutout when the screw thread diameter became larger than the endosteal diameter or within 80% of the outer cortical diameter as measured from the CT scan. Pedicle screws did not obtain cortical purchase within the pedicle.

Bone Screws↗

PubMed1989

The Wiltse pedicle screw fixation system. Early clinical results.

Ninety-nine patients were studied prospectively after spine fusion augmented with the Wiltse pedicle screw fixation system. Follow-up ranged from 12 to 34 months, averaging 20 months. There were 33 men and 66 women. Their ages ranged from 20 to 86, with the average age of 52. This was the first spine surgery in 23 patients. Seventy-six patients had had prior spine surgery. Spine fusion was attempted at one to four levels of the lumbosacral spine. Major perioperative complications were seen in seven patients (7%). Hardware failure was seen in seven cases (7%). Union was assessed by radiographs at 1 year or more after surgery in 82 patients (85%). In those 82 patients, union was seen in 56 (68%) and nonunion in 26 (32%). Change in lordosis was measured in 54 patients. The average change was a loss of 1.7 degrees lordosis per level fused. A questionnaire was answered by 79 patients (81%). Overall, 55 (70%) stated that they had some benefit from surgery, ten (13%) had no change, and 13 (17%) were worse.

Adult↗

PubMed1989

In situ arthrodesis without decompression for Grade-III or IV isthmic spondylolisthesis in adults who have severe sciatica.

Eight adults who had back pain and sciatica that was caused by Grade-III or IV isthmic spondylolisthesis of the fifth lumbar vertebra on the sacrum were treated consecutively by in situ arthrodesis without decompression. The anterior displacement of the fifth lumbar vertebra averaged 82 per cent (range, 66 to 118 per cent). The length of follow-up averaged 5.5 years (range, two to fourteen years). All of the arthrodeses resulted in a solid fusion and excellent relief of both the back pain and the sciatica. All of the preoperative neurological deficits resolved, with the exception of a decreased or absent Achilles-tendon reflex in two patients. There were no complications, and all of the patients returned to their preoperative occupations.

Adult↗

PubMed1987

Analysis of the morphometric characteristics of the thoracic and lumbar pedicles.

A total of 2,905 pedicle measurements were made from T1-L5. Measurements were made from spinal computerized tomography (CT) scan examinations and individual vertebral specimen roentgenograms. Parameters considered were the pedicle isthmus width in the transverse and sagittal planes, pedicle angles in the transverse and sagittal planes, and the depth to the anterior cortex in a line parallel to the midline of the vertebral body and along the pedicle axis. There was no significant difference between data obtained from CT scans and specimen roentgenograms. Pedicles were widest at L5 and narrowest at T5 in the transverse plane. The widest pedicles in the sagittal plane were seen at T11, the narrowest at T1. Due to the oval shape of the pedicle, the sagittal plane width was generally larger than the transverse plane width. The largest pedicle angle in the transverse plane was at L5. The posterolateral to anterolateral pedicle axis orientation in the transverse plane, seen at other levels throughout the thoracolumbar spine, reversed at T12. In the sagittal plane, the pedicles angled caudally at L5 and cephaladly from L3-T1. The depth to the anterior cortex was significantly longer along the pedicle axis than along a line parallel to the midline of the vertebral body at all levels with the exception of T12 and T11.

Adult↗

PubMed1986

Chemonucleolysis. A ten-year retrospective study.

An 11.8-year median follow-up evaluation of 42 "ideal" patients who had chemonucleolysis was obtained by examination, questionnaire, and roentgenograms. The excellent and good rating of this group was 81%, as compared to the total of 135 patients previously evaluated at 42 months and showing 85.2%. No complications were noted. Disc space rewidening, after initial narrowing, was observed in eight patients and 26% of all discs injected. While all who showed rewidening had excellent results, widening was not necessary to achieve an excellent rating. Marked narrowing and sclerosis of intervertebral margins were seen in many excellent and good clinical results. Chemonucleolysis represents a viable option as definitive treatment for a herniated nucleus pulposus in carefully selected patients.

Chymopapain↗

PubMed1986

A biomechanical study of intrapeduncular screw fixation in the lumbosacral spine.

This laboratory experiment was undertaken to identify factors contributing to intrapeduncular screw fixation in the vertebra. Testing was performed in axial pull-out and cyclic loading modes using multiple screw designs inserted to various depths into fresh human lumbosacral vertebra. The degree of osteoporosis played a major role in pull-out strength. Larger diameter, full-threaded screws inserted deep enough to engage the anterior vertebral cortex resulted in the most secure fixation. In the sacrum, the second sacral pedicle was the weakest location of insertion. Screws aimed laterally into the ala at 45 degrees or medially into the first sacral pedicle resisted larger axial pull-out loads than those inserted straight anteriorly into the ala. Methyl methacrylate was found to restore secure fixation in previously-loosened screws and pressurization of cement doubled the pull-out force. In cyclic load tests, deeper-inserted screws were found to withstand a greater number of cycles before loosening. Measurements of pedicle outer cortical diameters were found in many specimens to be smaller than both the 4.5-mm and 6.5-mm diameter screws.

Aged↗

PubMed1985

Treatment of degenerative spondylolisthesis.

The purpose of this article is to evaluate three surgical approaches to the treatment of degenerative spondylolisthesis. A review of 107 surgically treated cases were used to select a group of patients who met the following criteria: No previous spine surgery, no involvement in litigation, and no significant lesions at other levels of the spine. Adequate follow-up. The selected group of 47 surgically treated cases of degenerative spondylolisthesis had follow-up of 2-7 years. Three surgical approaches to the treatment of degenerative spondylolisthesis were analyzed. A relatively small patient group with a wide posterior decompression, at the level of the slip, sacrificing the articular processes had good to excellent results in only 33% of the cases. A second group with a midline posterior decompression with preservation of the articular processes had 80% good to excellent results after 2 years. The third group with a midline decompression and preservation of the articular processes had an added intertransverse process fusion between the olisthetic levels. This group had 90% good to excellent results. The conclusion is that a posterior decompression with preservation of the articular processes plus a transverse process fusion at the involved level is the preferred method of treatment for degenerative spondylolisthesis without regard to age.

Aged↗

PubMed1983

Safety and efficacy of chymopapain (Chymodiactin) in herniated nucleus pulposus with sciatica. Results of a randomized, double-blind study.

A double-blind, randomized trial was conducted to compare the efficacy of intradiskal injection of chymopapain (Chymodiactin) with injection of placebo in patients with a herniated lumbar disk. Patients were randomly assigned to either placebo or drug regimens and followed up for six months. The primary measure of performance was agreement by patient and surgeon that further intervention was not necessary. At any time that patient and investigator agreed that treatment had failed, the patient was classified as a failure and the treatment code was broken. Of 53 placebo-treated patients, 31 failed by this criterion. Of 55 drug-treated patients, 15 failed. Placebo-treated patients who failed were allowed to receive drug treatment, and 29 (91%) of 32 were treated successfully. This study demonstrates that chymopapain is more effective than placebo for treatment of patients with a herniated lumbar disk.

Adult↗

PubMed1975

Fatigue fracture: the basic lesion is inthmic spondylolisthesis.

The defect in the pars interarticularis in spondylolysis and spondylolisthesis is most often the result of repeated trauma, stress, and factors other than acute fracture. These fatigue fractures develop early in life, may have a strong hereditary basis, and most often represent incidental roentgenographic findings. Attention should be given to the youngster or adolescent with low-back pain and paraspinal muscle spasm. If these patients are followed closely, the incidence of pars interarticularis defect is higher than appreciated. The lesion in some of these individuals may progress to significant vertebral slipping. If the developing defect is recognized early, treatment can be quite satisfactory.

Adolescent↗