FRACTURE OF THE THORACOLUMBAR SPINE
S. M. Rezaian, M.D., Ph. D.
California Orthopaedic Medical Clinic, Beverly Hills, CA 90211. USA
Abstract. The Rezaian spinal Fixator (RSF) is a simple turn-buckle appliance with a fixation
mechanism on two extremities.
It simply replaces the compressed, burst, or damaged body of the vertebra. It corrects Kyphotic deformity, completely relieves neural pressure anteriorly, and stabilizes the spine for early rehabilitation. Hospitalization period is 7 to 14 days. No external support is required.
Key Words. Rezaian Spinal Fixator-Thoracolumbar spine fractures.
In 1986, Ferguson et al. gave an algorithm for the treatment of unstable thoracolumbar fracture. After extensive biomechanical testing of existent instrumentations of spinal fixation, they concluded that no one instrumentation was perfectly suited to handle all thoracolumbar fracture patterns. After improving their subliminal segmental L and C fixation technique, complications still were reported at 27.8%. The experiences of others are the same.
The spinal fixator described in this study represents a new approach for the management of fractures of the thoracolumbar spine.
In serious fracture of the thoracolumbar vertebrae with neurological deficit, the middle column commonly fails and the adjacent discs rupture; one or both protrude into the spinal canal. Furthermore, considering that 100% of the weight of the upper trunk is loaded over the bodies of the vertebrae, the basic stability of the spine as the weight-bearing axis is totally disturbed. Attempting decompression of the anterior part of the compressed cord from the posterior approach is difficult. Stabilization of the flexion moment by the posterior metallic splintage is mechanically unsound and consequently.
The Rezaian Spinal Fixator (RSF) has been invented to replace only the broken failed body of the vertebrae. It fully allows anterior decompression of the cord for a better neurological recovery, restores the failed body of the vertebrae, and corrects the kyphotic deformity for normal weight-bearing. It produces a secure stable spine for early rehabilitation. The need to include two of three vertebrae above and below the fracture site in mass fusion and the need for external support (e.g., cast, brace, jacket) are completely eliminated.
The Rezaian Spinal Fixator
The RSF is a form of a turnbuckle with a flat plate on each end, with four sharp spikes on each flat plate. Following the decompression of the cord, this appliance is embedded between the two adjacent intact vertebral endplates. At the same time, the height of the collapsed vertebral body is restored by turning the turnbukle mechanism; concomitantly, the kyphotic deformity is corrected. Based on a distraction compression mechanism, the fixator securely fixes and stabilizes the broken and unstable spine. It occupies approximately one-third of the body of the vertebra; two-thirds of the space is filled with bone graft when it is used for long-lasting fusion.
Experimental works on cadaver spine have proven that the procedure is biomechanically safe and sound. It allows decompression of the neural tissue, and does not demand inclusion of two or three vertebrae above and below the lesion. A section of rib and all broken pieces of the damaged vertebra will effectively bridge the vertebrae above and below the fixator and provide long-lasting fusion. Furthermore, the bone graft encircles the fixator and creates a safe barrier between it and vital structure (e.g. aorta and spinal cord).
The RSF is indicated for the management of fracture of the thoracolumbar spine in any of the following conditions:
- Replacing a diseased or injured vertebral body.
- Restoring the height of a collapsed vertebral body.
- Decompressing anteriorly the spinal cord and neural tissues.
- Reliving back pain followed spinal instability.
Generally, there is a combination of the above. The contraindications for RSF are.
- No neurological deficit present.
- Less than 15% compression of the vertebra.
The prerequisites for using a RSF:
A good spot X-ray of the damaged segment of the vertebra must be available.
CT and MRI scans.
A myelogram (still the final and best method of determining the extent of compression of the spinal cord and neural tissues).
At least 4 units of blood must be available for this operation. (Recently autotransfusion in conjunction with the cell saver was used without the need for hemotransfusion.)
General anesthesia is recommended with endotrachael intubation.Surgical Management
The left anterolateral approach is recommended. The patient is placed on his right side so that the left side of the body is elevated 45 degrees from the operative table. The right lower limb is flexed and the left is straight; the left arm is suspended. In this situation, the kidney support should be elevated so that about 20 degrees to 30 degrees lateral flexion with convexity to the left side is produced. The left side, from the midline of the anterior body, is prepped and draped in the standard fashion.
For the thoracic and thoracolumbar region, go through the bed of the rib above the lession, for example, in order to remove or replace the body of T12, the approach would be through the bed of the 11th rib, although this may expose T10-L3. We normally reach the bodies of the vertebrae through the retropleura and retroperitoneum to avoid morbidities resulting from thoracotomy.
It is preferable to utilize the intercostal nerve as a guide to enter into the lateral side of vertebral just in front of the intervertebral foramen. From this point up and forward, one might take the damaged piece of vertebral body until the spinal canal and epidural space is fully exposed. At this time, the anterior part of the cord is decpressed. If, however, the myelogram has shown that there was compression on the spinal cord and dura over it will expand and will be visualized in the form of a sausage. The damaged vertebral body (one or more) and the adjacent discs are removed. Normally, it is recommended that the anterior part of the canal be completely decompressed. In addition, a space should be made inside that vetebra for placement of the spinal fixator.
After completing this stage, the distance between the adjacent intact vertebrae is measured, and one of the four sizes of the RSF is chosen for insertion. Any displacement at this stage may be completely corrected under direct vision. without damage to neural tissues. The spinal fixator is inserted into the provided space. It distracts the spine until the height of the damaged vertebra is restored. After that, a small slit of about 1 cm is made on the anterolateral edge where the damaged vertebra and disc were removed. Suitably sized piece of the 11th rib, removed during the approach, are inserted in these slits so that the adjacent vertebrae are biologically connected and the anterior column of the vertebra is restored. A second split of rib graft may be laid down between the intact vertebrae on the posterolateral aspect if possible. Then the rest of the spongeous bone is inserted between the graft, and the remainder of the vertebral body and spinal fixator. An X-ray to reassure satisfactory position of the spinal fixator should be made. It si generally recommended that two hemovac suction units be placed: one in the retropleural and the other in the retroperitoneal cavity.
As part of general mangement, as in all major operations, an X-ray must be taken to ensure that the position of the spinal fixator is satisfactory. The patient may be allowed to sit 1 to 3 days after the operation. Wound suction drains are removed after 48 hours. If the patient is completely paralyzed, he must be measured for braces; if he is able to be ambulated with or without crutches, he should be allowed to do so 5 to 7 days after the operation. The patient may leave the hospital as soon as the wound is healed. Respiratory therapy for expansion of the lungs, particularly for the first 3 days after the procedure, is also important. No particular complications can occur after the wound has completely healed. Our experience shows that the spinal fixator becomes imbedded in bone, and that bone haling takes place around it. Because the spinal fixator is generally well tolerated by the body, it is not necessary to remove the applicance. The patient may be discharged as soon as the wound is healed, normally 10 to 14 days after the operation.Materials and Results
The preliminary reports of the first 24 cases were presented at the annual meeting of the Scoliosis Research Society in 1981. Since then, 41 more procedures have been performed, for a total of 65 cases (29 women and 36 men). Their ages ranged form 17 to 72 years; 11 were complet and 54 were incomplete paraplegic cases. The etiology was primary (single myeloma) in one case, secondary metastasis in three cases, sequestrum of osteomyelitis with severe neurological involvement in four cases, and spondylolisthesis grade V with incomplete paraplegia and compressed osteoporotic fracture of T12 and L1 in three cases. The other 54 cases were traumatic with quariplegia in one case and incomplete or complete paraplegia in 53 cases. Details of the levels of lesions are recorded in Table 1. Minimal follow-up time was 3 years, and maximum follow-up time was 8 years (average tiem, 4 years and 4 months).
No patient was operated on immediately after sustaining injury. The minimal interval of time between the accident and the operation was 16 days, and the maximum was 18 months. Minimal hospitalization time was 5 days, maximum 27. Repeat surgery was necessary in two cases due to malposition of the fixator. The detail of 43 fracture of thoraes lumbar is recorded in another paper under review.
No patient worsened neurologically; in contrast, all incomplete paraplegic cases were able to be ambulated. Out of 53 incomplete paraplegic cases, 41 patients returned to normal or near normal activities, five had to use a cane for ambulation, and seven had to have a short splint for drop foot or unstable ankles. One case of quadriplegia improved from grade A to grade C.
No patient needed any external support (e.g., back brace, cast, etc. ) It is important to note that the spines operated upon were always stable and pain-free under normal loading. No deformaties of the spine were noticed in this group or in follow-up and routine X- ray examinations. Three cases are described in detail as examples. No instrument failure was noticed.
Level of Spinal Replacement
|Level of Injury
|Thoracic Spine T1-T10
|Thoracolumbar Spine T11-L3
|Lumbar Spine L4-L5