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Translaminar screw fixation offers an immediate postoperative stability of the lumbar and lumbosacral spine and enhances fusion. In the present series no neurologic complications were noted. It represents a useful and inexpensive technique for short segment fusion of the nontraumatic lumbar and lumbosacral spine.

IntroductionFixation of the lumbar and lumbosacral spine with pedicle screws is presently the most common technique for internal fixation in the lumbar spine, and has been widely used for a variety of indications for almost 30 years [26,27,35]. However, the use of posterior internal fixation to increase fusion rates was first attempted, to our knowledge, as early as 1891, when a wiring technique for spinal fusion was introduced by Hadra [14]. Reports of various techniques with different implants were published in the following years. The use of facet screws was first reported by King in 1948 [24], whose technique was to immobilize the lumbosacral joints with a short screw, transversing the facet. With his technique, he achieved a fusion rate of 91% without prolonged rigid external fixation postoperatively. Boucher [4a] reported a slightly different technique of screw insertion. He tried to improve the bony purchase by penetrating the ipsilateral pedicle with the tip of the screw. Using this technique, he considerably improved the fusion rate, which he reported as 100% in single-level fusions. However, the tip of the screw had to be placed near the foramen and the nerve root, which carries potential risk of injury.Another modification of the technique of transfixing facets with screws was introduced by Magerl in 1984 [27]. Magerl's idea of inserting the screw from the contralateral side, through the lamina, eliminated the disadvantages of the former techniques without losing their advantages. Bony purchase was increased by the passage of the screw through the lamina, and the procedure is less risky, as (1) the insertion of the screw is clearly posterior to the neural elements and can be performed under direct visual control, and (2) the direction of the screw is parallel to the exiting nerve root.The present review is based on a vast experience covering 15 years of clinical application of translaminar screws. It focuses on the indications, advantages, and contra-indications of this technique.Abstract Translaminar screw fixation of the lumbar spine represents a simple and effective technique for short segment fusion in the degenerative spine. Clinical experience with 173 patients who underwent translaminar screw fixation revealed a fusion rate of 94%. The indications for translaminar screw fixation as a primary fixation procedure are: segmental dysfunction, lumbar spinal stenosis with painful degenerative changes, segmental revision surgery after discectomies, and painful discrelated syndromes such as internal disc disruption and lumbar disc herniation with concomitant degenerative changes. As an additional stabilization procedure, translaminar screws can be used to augment anterior fusion or reinforce pedicle systems. Translaminar screw fixation achieves as high fusion rate provided the biomechanical principles of the lumbar spine with an intact anterior column are respected and a meticulous operative technique is employed to enhance bony ingrowth of the graft.

In inveterate cases of grade 2-3 spondylolisthesis (degenerative or spondylolytic), segmental mobility may be reduced by radiologically confirmed disc resorption. Fusion may be indicated in patients with persistent pain. A simple technique for fusion without reduction of the spondylolisthesis is presented. Fixation of the segment is achieved by two cancellous bone screws inserted bilaterally through the pedicles of the lower vertebra into the body of the upper slipped, vertebra. The cases of 16 patients with an average follow-up of 31 months (range 24-27 months) treated with this direct pediculo-body fixation are presented. Clinical evaluation showed significant decrease in pain and, in patients with concomitant spinal stenosis, walking distance without pain improved from between 500 and 1000 m to more than 3000 m. Radiologically, fusion was observed in all cases. The presented technique of internal fixation of a slipped segment in the degenerative lumbar spine represents a simple minimally traumatic procedure with successful clinical and radiological outcome. Additional procedures, such as decompression of the spinal canal, may be performed.

Between 1968 and 1977, 72 patients with idiopathic scoliosis underwent Harrington Instrumentation (HI). Between 1985 and 1988, 21 patients with idiopathic scoliosis had posterior spinal fusion with Cotrel-Dubousset instrumentation (CDI). All patients were operated by the same orthopedic surgeon. None of the CDI patients had postoperative brace or cast protection, the HI group had on average 6 months' postoperative brace treatment. The two groups of patients were comparable in age, sex, and type of curves. The HI group and CDI group were reexamined with clinical and radiological assessment after mean periods of 148 months and 60 months respectively. The average preoperative Cobb angle in the CDI group was 59.9 degrees (HI group 67.8 degrees), which improved to 20.8 degrees (HI group 33 degrees) postoperatively--a correction of 66.3% (HI group 51.3%). The loss of correction on reassessment amounted to 5% in the CDI group and 20.7% in the HI group. In both groups, the mean rib hump height was reduced to 2.2 cm. In 40% of the Harrington patients, a flat back was found, but this was not related to clinical back pain. The rate of complications and reintervention was 9.5% in the CDI group and 8.3% in the HI group. There were no neurological complications. Subjectively, 86% of the Harrington patients and 95.2% of the CDI patients rated the results of their operation as "good" or "very good." The CDI group showed better results in correction of the Cobb angle and loss of correction, while saving one mobile lumbar segment. The correction of the rib hump showed the same results for both techniques. Blood loss and operation time was much lower in the HI group. However, the rate of complications was similar in both groups.