Transpedicular Stabilization Research Articles

Limitations of dorsal transpedicular stabilization in unstable fractures of the lower thoracic and lumbar spine: an analysis of 133 patients.

The optimal treatment of thoracic and lumbar fractures remains controversial. While many authors recommend dorsal instrumentation with an internal fixator, others favour an anterior approach. To evaluate the posterior approach and to identify conditions under which an anterior approach should be preferred, 133 patients with unstable thoracic and lumbar fractures of the spine who underwent dorsal instrumentation with an internal fixator were analyzed. Clinical data were recorded prospectively with respect to fracture type, neurological findings, operative complications, spinal deformation correction, and long-term outcome. All fractures were located between the 7th thoracic and the 5th lumbar vertebrae and were considered to be unstable with respect to the three column model. Seventy-six patients (57%) received surgery within the first seven days after the trauma. Postoperatively, 98% of patients with a radicular lesion or an incomplete transverse syndrome (47 patients, 35%) improved. Stable fracture consolidation after fixator removal was obtained in 98% (130 of 133 patients). The preoperative kyphosis angle decreased from an average of 10.1 degrees to 7.4 degrees at the three year follow up. Major operative complications consisted of two isolated nerve root lesions (1.5%), two deep wound infections with need of fixator removal (1.5%), and mallocation of two pedicle screws with need for another procedure in two patients (1.5%). Three patients (2%) suffered from insufficient bony fusion with increase of kyphotic deformation and required subsequent anterior stabilization. These three patients presented with an initial kyphosis or wedge angle of 20 degrees or higher. In conclusion, dorsal stabilization with the internal fixator is a safe and reliable treatment for unstable fractures of the lower thoracic and lumbar spine. The authors recommend this procedure because of its low-invasiveness in conjunction with satisfactory reconstruction and stabilization. However, an anterior approach should be considered in fractures with initial kyphotic deformation or wedge angle of 20 or more degrees.

Vertebral body replacement system Synex in unstable burst fractures of the thoracic and lumbar spine--a retrospective study with 30 patients

Retrospective analysis of the vertebral body replacement system Synex in unstable burst fractures of the lumbar and thoracic spine. Within 22 months, we treated 30 patients (average age: 45, range: 20- 73 years, 16 females, 14 males) with unstable burst fractures of the thoracolumbar (n=20) and the thoracic (n=2) as well as lumbar (n=8) spine in two stages (primary dorsal transpedicular stabilization with fixateur interne under navigator guidance and intraoperative CT and secondary vertebral body replacement using the Synex). In three patients with osteoporosis we performed additional ventrolateral plate fixation. The complications of the operation were analyzed and the postoperative follow-up results were evaluated regarding stability, bony fusion, loss of correction, pain and neurological status. There was one postoperative instability, two transient neurological deteriorations and one case with seroma of the pleura. At follow-up examination (mean follow-up 14 months) an average loss of correction of 1.6 degrees was measured. Without osteoporosis a loss of correction of 5 degrees was observed in one case. In four osteoporotic patients without ventrolateral stabilization a mean loss of correction of 10 degrees was present. At the follow-up examinations a bony fusion was documented in 27 and stability in all patients. Most of the patients stated either no or only minor pains at follow-up. Only two patients with pain of medium degree had to take pain medication. The vertebral body replacement system Synex is a good technical possibility for a vertebral body replacement in unstable burst fractures of the thoracic and lumbar spine. With osteoporosis an additional anterior stabilization is to be recommended.

Interbody Fusion in Thoracolumbar Fractures (T11-L2) Using the Percutaneous Dorsolateral Technique

Background: The authors' concept of reduction and stabilization of thoracolumbar fractures has become more sophisticated. Depending upon the fracture classification, a posterior transpedicular, an isolated anterior or a combined approach is used. Fractures with a low degree of vertebral body comminution and only one-space disk injury are reduced and stabilized by the transpedicular approach. For reliable anterior interbody fusion, the percutaneous, dorsolateral, fluoroscopically controlled application of hydroxyapatite granules has become the method of choice. To obtain better osteoconductive properties, the granules are inoculated with autologous bone marrow. A special instrument set is available for application. Patients and Methods: In a prospective clinical study, the long-term results after posterior transpedicular stabilization of thoracolumbar spine fractures (T11–L2) were followed-up. Success or failure of the method was shown by the loss of correction of the postinjury kyphosis, measured by the angle β on lateral X-rays. Results: In 66 patients, undergoing the above surgical procedure with application of synthetic hydroxyapatite granules, the loss of correction was measured 6, 12, and 24 months postoperatively. Intrinsic stable devices for transpedicular stabilization were used in all cases. After 6 months an average loss of correction of 1.54° was measured, which amounted to 3.05° after 12 months and to 4.13° after 2 years. These values proved to be better than the results of an earlier study, in which we used the same technique, but with autologous and/or allogeneic bone grafts (2.49° after 6 months, 6.30° after 12 months). The loss of correction 1 year after surgery was statistically significantly greater in the group of bone graft recipients compared to the group treated with bioceramic granules (p < 0.001, Mann-Whitney U-test). 6 months after surgery, no statistical significance was observed. Conclusions: The results imply that 1 year postoperatively, the percutaneous, dorsolateral interbody fusion technique with hydroxyapatite granules after transpedicular stabilization shows better results than a similar procedure with interbody fusion technique using bone grafts.

Posterior transpedicular stabilisation of the infected spine.

Six men and seven women, aged 62 years, bedridden due to back pain from a septic spondylitis in the thoracolumbar region and not responding to conservative treatment, were operated on with transpedicular stabilisation of the affected segments to enhance mobilisation. All patients experienced immediately reduced back pain, allowing them to leave their bed and start mobilisation during the first postoperative day. At follow-up after a mean of 29 months (range 13-60 months) only one was using analgesics. Nine of the 11 patients with pathological neurology at surgery had improved, none had deteriorated, and all were ambulatory without bladder or bowel disturbances. Seven had achieved a solid interbody fusion, with a continued radiographic decrease in the spondylitic change in the rest, indicating that a progressive interbody fusion was in progress. Three individuals had increased kyphosis, a mean of 11 deg compared with the postoperative radiographs.

In vitro testing of a new transpedicular stabilization technique.

The rigidity of a pedicle screw implant is a critical biomechanical variable in lumbar spinal fusions. Sufficient rigidity is required for integration of bone grafts and to promote healing. Osteopenia, stress shielding, and compensatory hypermobility have been described as consequences of excessive rigidity. Little is known about the biomechanical characteristics of "semirigid" compared to "rigid" implants. A new implant, whose rigidity can be varied by selection of different implant components, was tested in vitro under well-defined loading conditions. The three-dimensional load-displacement behavior of all lumbar vertebrae involved in or adjacent to the two-level fusion was evaluated for two fusion modifications: bilateral rigid and bilateral semirigid. Cyclic fatigue loading was subsequently carried out under realistic conditions and motion testing repeated. The rigid device reduced the motion of the L3-4 transfixed segment in the primary movement planes by 87.3% with respect to the intact spine value in flexion/extension (FE), 86.3% in lateral bending (LB), and 76.8% in axial rotation (AR). The semirigid device achieved a reduction in motion of 79.6% (FE), 82.7% (LB), and 51.7% (AR). The semirigid implant was particularly easy to insert, because no bending of rods or plates was necessary. The implants showed no loosening or breakage after the fatigue testing. The results are compared to other available systems and the underlying biomechanics discussed.

Transpedicular lumbosacral stabilization in spinal disorders: current aspects

Transpedicular lumbosacral stabilization in spinal disorders: current aspects

Complications after transpedicular stabilization of the spine. A survivorship analysis of 163 cases.

The authors studied complications of transpedicular stabilization methods. One hundred and sixty-three consecutive transpedicular stabilization procedures were performed between January 1987 and December 1991. The indications for stabilization were trauma (33 cases), metastatic spinal disorder (30 cases), spinal stenosis (33 cases), spondylolisthesis (27 cases), ankylosing spondylitis (6 cases), low back pain (22 cases), and miscellaneous (12 cases). Patients records and the entire series of radiographs for each case were scrutinized by independent observers. All per- and postoperative complications, including implant loosening and fatigue, were recorded. Clinical and radiographic survivorship analyses of the implants were performed. Early complications were unusual and none were associated with permanent morbidity. The probability of not having the implant removed in the first postoperative year was 85%. There was a 40% risk of radiographic failure, defined as loosening or implant fatigue, at 6 months. The outcome was more favorable in cases in which anterior vertebral interbody fusion was also performed. Transpedicular fixation is a safe procedure with a low incidence of serious per- and early postoperative complications. The mechanical durability of transpedicular fixators used alone is a cause for concern.

Kluger's ?Fixateur interne? for spinal instability

Kluger's "Fixateur Interne" proved to be an excellent tool not only in spinal trauma for repositioning of impacted fractures and transpedicular stabilization of the dorsal column but also in other forms of thoracic or lumbar instability. After spinal tumor excision from a dorsal approach and vertebral replacement with methylmethacrylate additional stability through dorsal fixation was achieved with this device. Spondylodiscitis, symptomatic spondylolisthesis, spinal instability from degenerative disc disease as well as "non-union" following previous surgery could be cured using Kluger's internal fixation. Rare complications, i.e. from broken screws or rods (5%) caused no problems, but some patients required a second operation for readjustment of malpositioned screws which were causing pain or neurological deficit.