Search

Anterior fixation devices for the thoracolumbar spine have gained wide acceptance as viable alternatives to long-segment posterior fixation in cases of thoracolumbar spine trauma. This review was undertaken to evaluate the safety and efficacy of the Synthes anterior thoracolumbar locking plate (ATLP) system. Over a 3-year period, 31 patients with unstable traumatic fractures of the thoracolumbar spine underwent corpectomy, placement of a structural bone graft, and anterior fixation in which the Synthes ATLP system was used. Long-term follow-up data were obtained in 29 patients. Two patients were lost to follow up, one at 4 months and the other at 1 year. In the remaining patients, the average length of follow up was 20 months. In all patients radiographic evidence of solid bone fusion was demonstrated on follow-up plain x-ray films, and there were no signs or symptoms of pseudarthrosis. No patient suffered neurological deterioration as a result of surgery, and there was relatively little morbidity associated with this plating system. To date, none of the patients in this study has developed any delayed complications related to the fixation device. In one patient, who had sustained a severe flexion injury, loosening of the anterior fixation device occurred, and the patient developed progressive kyphosis, which required a posterior stabilization procedure. These results appear slightly better than those obtained in published studies in which other anterior plating systems were used, indicating that this system is safe and effective in the treatment of unstable fractures of the thoracolumbar spine.

Combined anterior and posterior fusion with posterior instrumentation may be indicated in the treatment of select cases of L5-S1 spondylolisthesis. The instrumentation, however, is expensive and usually bulky, occasionally requiring removal. In an effort to avoid these problems, an L5-S1 paralaminar screw technique was developed for posterior stabilization after an L5-S1 anterior interbody fusion. The technique involves the placement of cortical screws from the base of the articular process of S1 to the pedicle of L5. This study evaluates the anatomic applications and clinical results of this technique. The relationship between the screw and L5 nerve root was examined using five cadaveric specimens with olisthesis of 0, 25, 50, and 75%. This work demonstrates that the screws can only be inserted safely if an L5-S1 olisthesis of at least 25% is present. If < 25%, the screws will either impinge on or directly injure the L5 nerve root. In the clinical study, the outcomes of 20 patients who had an isthmic spondylolisthesis of 25-81% and were treated with partial reduction, L5-S1 anterior interbody fusion, and L5-S1 posterior paralaminar screw fixation were reviewed. Nineteen patients had adequate posterior stabilization to completely heal an L5-S1 anterior interbody fusion without loss of the correction. In one patient, a pseudarthrosis occurred secondary to poor surgical technique of both anterior and posterior fusions. This patient required an additional L4-S1 posterior fusion 9 months later and had a good clinical outcome. No other complications due to screw placement occurred. We conclude that this procedure can be used safely and reliably for the posterior stabilization of L5-S1 after stable anterior L5-S1 interbody fusion in residual slips of at least 25%. Prerequisites are proper patient compliance and low weight. Compared with other posterior instrumentation systems, this screw fixation is inexpensive and does not require implant removal. The disadvantages of the method are the degree of difficulty of the procedure and the limited clinical application to cases of L5-S1 spondylolisthesis with corrected residual slips of 25 to 50-60%. The procedure is technically demanding and should be limited to those surgeons who are comfortable with the method.

Certain injuries of the thoracolumbar junction disrupt spinal stability by interrupting both the anterior and posterior supporting columns of the spine. Spinal cord injury occurs in these injuries as a result of insult from an anterior direction. Proposed management should include both posterior stabilization of the spine and anterior decompression of the cord, all accomplished, ideally, under one anesthetic. Five illustrative cases demonstrate the principles and outcomes of this approach.

An alternative method of cervical fixation utilizing a stainless steel clamp is described. The clamp is applied to the adjoining laminae of involved vertebrae in those cervical dislocations and subluxations with posterior instability. The long term results of this method have been most satisfactory, as indicated by our follow-up of 51 patients treated during the last decade.

Metastatic lesions of C1 and C2 most frequently present with severe pain and only rarely with neurologic involvement. The lesions are poorly visualized on plain roentgenogram and most often require bone scan and/or computed axial tomography (CAT) scan for definitive diagnosis. Delay in diagnosis in frequent in these patients (8 of 16). Radiation therapy and external mobilization yield satisfactory results for minor fractures or diffuse involvement without instability. Surgery is rarely indicated for decompression. However, in patients with C1 lateral mass involvement or severe C2 body destruction with instability, posterior stabilization gives excellent relief of pain. Onset after diagnosis of the primary tumor ranges from months to years. Survival is reasonable (mean, 9 months) after diagnosis of upper cervical spine involvement. Understanding these characteristics and the occurrence of metastatic disease in the upper cervical spine allows earlier diagnosis with appropriate radiographic studies and prompt palliation of symptoms.

Posterior stabilization of thoracolumbar spine fractures has been shown to be safe and effective when performed by surgeons versed in the technique devised by Harrington. In this study, 25 patients are reviewed whose spine fractures were operatively treated in a general orthopedic community. Although the overall results and rate of complications and failures have not been found to be significantly greater than those previously reported, a large number of deviations from standard operative technique have been identified (56%). These technical faults are related to the clinical complications and failures.

Postmortem examination of a spine, which had been instrumented anteriorly at one level and posteriorly at another following vertebral body resections, showed that the posterior instrumentation was more effective in resisting torsion. Postmortem examination of a second case, where the anterior fixation had been strengthened by the addition of cement studs in the vertebral end-plates and a paravertebral modified and strengthened Zielke screw/rod system, showed this second anterior system to be an improvement for resisting torsion following the resection of one vertebral body. Anterior interbody devices become enveloped in a firm smooth fibrous capsule. A preliminary experiment on a cadaver spine had shown that anterior interbody fixation was better than posterior instrumentation for resisting flexion-compression forces.

Twenty-four patients who had a major complication after attempted stabilization of the spine with methylmethacrylate were referred for treatment. The initial instability that necessitated stabilization was caused by a traumatic condition in fifteen of these patients and by a metastatic tumor in nine. The average length of time before failure of fixation was 208.3 days for the patients who had a traumatic condition and 193.7 days for those who had a neoplasm. In eleven patients a progressive neural deficit developed postoperatively, and in six others the recovery of neural function was possibly hindered by the cement. A deep wound infection developed in six patients, and in five of them treatment by removal of the methylmethacrylate and metal, followed by a prolonged period of cervical traction, was required. Loosening and failure of fixation was the most common complication--it occurred in twelve of the fifteen patients who had a traumatic lesion and in eight of the nine who had a neoplasm. Salvage operations that included removal of the cement and conventional bone-grafting procedures were performed in eleven of the twelve patients who had loosening associated with a traumatic lesion and in six of the eight who had loosening and a tumor. Stability was restored in every patient. Improved long-term results can be achieved by using grafts of iliac bone and triple-wire stabilization methods (a midline wiring between the spinous processes and two iliac-crest grafts, one on each side, wired to the posterior elements) instead of methacrylate in the primary treatment of traumatic injuries. The treatment of choice for instability caused by neoplastic destruction of two or more vertebral bodies includes a construct of methylmethacrylate anteriorly. However, if cement is used, early augmentation with posterior fusion of the spine and stabilization should be considered. As a rule, combined anterior and posterior stabilization is recommended for the reconstruction of a spine that is unstable due to neoplastic destruction. In general, whenever methylmethacrylate is used for spinal stabilization, it should be augmented with grafts of iliac bone to provide long-term stability.

Twenty-four patients had a combined anterior cervical decompression and posterior stabilization with circumferential spinal arthrodesis for treatment of either a tumor or an injury. The indication for operation was a fixed kyphosis and an incomplete neurological deficit or cervical instability. All but two patients had substantial improvement, having regained strength or had a reduction in the deformity, or both. The two exceptional patients, both of whom were quadriparetic, had no change. The operation is formidable and requires an average of 6.9 hours of general anesthesia; however, its use is justified in patients who have the appropriate indications.

Anterior interbody grafts are prone to displacement if there is posterior instability or gross deformity of the vertebral body. Twenty-one patients treated with anterior interbody fusion for cervical vertebral fractures and dislocations were studied. Twelve of the fractures were considered unstable preoperatively, and 50% of this group treated with anterior stabilization had graft migration postoperatively. If anterior fusion is used in unstable cervical fractures then posterior stabilization or complete bed rest with effective external stabilization (i.e., tongs or Halo-thoracic brace) for 4 weeks is mandatory. The other alternative is posterior stabilization before anterior decompression. In the presence of posterior instability, anterior interbody fusion alone cannot be recommended as the treatment of choice for cervical fractures.

Surgical treatment of patients suffering from spinal extradural metastases will be decided on with the aim of preventing an impending paraplegia and of eliminating the often concomitant radicular pain (3).

Under certain clinical conditions, posterior stabilization of the cervical spine, supplemented with polymethylmethacrylate (PMMA), is an accepted method of achieving stability. A technique is described in which "cement forms" are used to limit the spread of PMMA and to allow bone graft placement in the lateral paraspinous gutters.

A series of 105 operative cases of thoracic and lumbar spine trauma is presented. All patients underwent an anterior decompression and fusion via the lateral extracavity approach with or without an accompanying posterior internal stabilization procedure (modified Weiss springs or Harrington distraction rods). All patients were allowed to plateau neurologically before reconstructive spine surgery was performed. The patient's neurological grade at the time of surgery and after recovery was assessed according to a seven-grade scale presented herein. None of the 34 patients with a motor and sensory complete myelopathy recovered any function below the level in injury. Of the 10 motor-complete patients with some sensory perception, 4 improved neurologically; however, only 1 of these improved to a state of limited ambulation. The rest remained nonambulatory. Of the 33 patients with significantly disabling incomplete motor and sensory myelopathies, 17 improved to a level of minimal neurological deficit; only 3 patients were left nonambulatory. Of the 21 patients whose physical finding demonstrated a minimal neurological deficit preoperatively, 17 recovered to a normal neurological state. Seven patients were neurologically normal preoperatively and were unchanged postoperatively. Reconstruction of the spine with an anterior decompression and an accompanying stabilization procedure, when appropriate, leads to a better neurological outcome than that expected with either a conservative, nonoperative approach or an operative posterior stabilization approach.

✓ Methyl methacrylate (acrylic) was used in fusion techniques in 82 patients, most of whom had metastatic disease, between 1959 and 1979. In all cases the acrylic was used to supplement stabilization with Meurig-Williams stainless steel plates or with wire. In cases involving a decompressive laminectomy and excisional biopsy (radical resection of a tumor mass) that required posterior stabilization, acrylic helped to achieve rapid fusion with excellent results. The series included one anterior fusion with acrylic and nine atlantoaxial fusions in patients without tumors. Strict guidelines for selection of patients are outlined. The advantage of acrylic over bone fusion in selected patients is discussed. Careful follow-up studies including autopsy examinations are included. The technique of the use of acrylic is outlined. There was no case of late instability. There was one instance of infection in a patient who was immunodeficient and in whom a combination acrylic and bone fusion was performed. Tissue reaction to the acrylic in autopsy specimens is discussed.

Threaded compression rods were placed between the posterior-superior spines as a means of posterior stabilization of pelvic fractures. To document the increase in sacroiliac stability afforded by this technique, biomechanical testing was performed. Malgaigne-type fractures with sacroiliac disruptions were created in four cadaver pelvises. The fractures were stabilized with anterior frames of the Slatis or Pittsburgh type and subjected to longitudinal and torsional loading patterns on an Instron machine. The anterior fixation was then augmented with threaded compression rods placed between the posterior-superior spines to compress the disrupted sacroiliac joints, and repeat testing was conducted. Anterior frames alone were found to provide little stabilization of the disrupted sacroiliac joints with either longitudinal or torsional loading. Markedly improved stabilization in both loading modes was achieved with posterior augmentation. Two typical cases are presented to demonstrate that posterior stabilization is as efficacious in clinical practice as in the biomechanics laboratory.