No abstract available.
Zygapophyseal Joint*

OBJECTIVES: An in vitro biomechanical study of posterior lumbar interbody fusion(PLIF) with threaded cage using two different approaches was performed on eighteen functional spinal units of bovine lumbar spines. The purpose of this study was to compare the segmental stiffnesses among PLIF with one long posterolateral cage, PLIF with one long posterolateral cage and simultaneous facet joint fixation, and PLIF with two posterior cages. METHODS: Eighteen bovine lumbar functional spinal units were divided into three groups. All specimens were tested intact and with cage insertion. Group 1(n=12) had a long threaded cage(15x36mm) inserted posterolaterally and oriented counter anterolaterally on the left side by posterior approach with left unilateral facetectomy. Group 2(n=6) had two regular length cages(15x24mm) inserted posteriorly with bilateral facetectomy. Six specimens from group 1 were then retested after unilateral facet joint screw fixation in neutral(group 3). Likewise, the other six specimens from group 1 were retested after fixation with a facet joint screw in an extended position(group 4). Nondestructive tests were performed in pure compression, flexion, extension, lateral bending, and torsion. RESULTS: PLIF with a single cage, group 1, had a significantly higher stiffnesses than PLIF with two cages, group 2, in left and right torsion(p<0.05). Group 1 showed higher stiffness values than group 2 in pure compression, flexion, left and right bending but were not significantly different. Group 3 showed a significant increase in stiffness in comparison to group 1 for pure compression, extension, left bending and right torsion(p<0.05). For group 4, the stiffness significantly increased in comparison to group 1 for extension, flexion and right torsion(p<0.05). Although there was no significant difference between groups 3 and 4, group 4 had increased stiffness in extension, flexion, right bending and torsion. CONCLUSION: Posterior lumbar interbody fusion with a single long threaded cage inserted posterolaterally with unilateral facetectomy enables sufficient decompression while maintaining a majority of the posterior elements. In combination with a facet joint screw fixation, adequate postoperative stability can be achieved. We suggest that posterolateral insertion of a long threaded cage is biomechanically an ideal alternative to PLIF.
Decompression ; Spine ; Zygapophyseal Joint

No abstract available.
Intervertebral Disc* ; Zygapophyseal Joint*

No abstract available.
Spondylolisthesis* ; Zygapophyseal Joint*

No abstract available.
Prolapse ; Tropism ; Zygapophyseal Joint

No abstract available.
Prolapse ; Tropism ; Zygapophyseal Joint

No abstract available.
Spine* ; Zygapophyseal Joint*

This study analyzed 88 patients who sustained a cervical spine injury during the past 4 years(Jan, 1993-May, 1996) in whom had 33 anterior, 21 posterior interventions were underwent and 34 remaining patients recieved conservative treatment with halovest. In 45 cases of upper cervical injuries, 16 operations were done. Among these, anterior approach was used in 3 patients and posterior approach in 13 patients. In 43 cases of lower cervical injuries, 39 operations were done. The anterior approach was used in 30 patients, posterior approach in 9 patients, and bilateral approached in remaing 4 cases. For patients with a predominent posterior ligamentous or osteoligamentous lesion, we selected anterior approach, when closed reduction was possible. Whenever the facet joint remained interlocked, a posterior approach was chosen. This report does not mentioned priority of anterior procedure at any case. Although clinical experience does not support the experimental data, we examined the reliability of anterior approach with use of internal fixation.
Humans ; Ligaments ; Spine* ; Zygapophyseal Joint

Although posterior segmental fixation technique is becoming increasingly popular, surgical treatment of craniovertebral junctional disorders is still challenging because of its complex anatomy and surrounding critical neurovascular structures. Basilar invagination is major pathology of craniovertebral junction that has been a subject of clinical interest because of its various clinical presentations and difficulty of treatment. Most authors recommend a posterior occipitocervical fixation following transoral decompression or posterior decompression and occipitocervical fixation. However, both surgical modalities inadvertently sacrifice C0-1 and C1-2 joint motion. We report two cases of basilar invagination reduced by the vertical distraction between C1-2 facet joint. We reduced the C1-2 joint in an anatomical position and fused the joint with iliac bone graft and C1-2 segmental fixation using the polyaxial screws and rods C-1 lateral mass and the C-2 pedicle.
Decompression ; Joints ; Transplants ; Zygapophyseal Joint

Osteoid osteoma (OO) is a benign osteoblastic tumor. Its curative treatment is complete removal of the nidus, where intraoperative localization of the nidus governs clinical results. However, treatment can be difficult since the lesion is often invisible over the bony surface. Accordingly, establishment of an ideal less invasive surgical strategy for spinal OO remains yet unsettled. We illustrate the efficacy of a computed tomography (CT)-based navigation system in excising OO located adjacent to the facet joint of spine. In our 2 cases, complete and pin-point removal of the nidus located close to the facet joint was successfully achieved, without excessive removal of the bone potentially leading to spinal instability and possible damage of nearby neurovascular structures. We advocate a less invasive approach to spinal OO, particularly in an environment with an available CT-based navigation system.
Osteoblasts ; Osteoma, Osteoid* ; Spine* ; Zygapophyseal Joint*