Comparative analysis between shape memory alloy-based correction and traditional correction technique in pedicle screws constructs for treating severe scoliosis

The three-dimensional correction of severe rigid scoliosis has been improved by segmental pedicle screw instrumentation. However, there can be significant difficulty related to the use of a rigid rod, especially in the apex region of severe scoliosis. This study is a retrospective matched cohort study to evaluate the advantages of Nitinol shape memory alloy (SMA) rod-based correction by comparing the clinical and radiographic results obtained from using a temporary SMA rod and those from a standard rod in the correction of severe scoliosis. From May 2004 to September 2006, patients with matched curve type, ages at surgery, operative methods and fusion levels in our institute and instrumented with either SMA rods (n = 14) or traditional correction techniques (n = 16) were reviewed. In SMA group, the SMA rods served as a temporary intraoperative tool for deformity correction and were replaced by standard rods. The blood loss at surgery averaged 778 ± 285 ml in the traditional group and 585 ± 188 ml in the SMA group (P < 0.05). Operative time averaged 284 ± 53 min in the SMA group and 324 ± 41 min in the traditional group (P < 0.05). In the SMA group, the preoperative major curve was 92.6° ± 13.7° with a flexibility of 25.5 ± 7.3% was corrected to 29.4° ± 5.7° demonstrating a 68.4% immediate postoperative correction. In the traditional group, the preoperative major curve was 88.6° ± 14.6° with a flexibility of 29.3 ± 6.6% was corrected to 37.2° ± 7.3° demonstrating a 57.8% immediate postoperative correction. There was a statistic difference between the SMA group and traditional group in correction rate of the major thoracic curve. In the SMA group, one case suffered from deep infection 2 months postoperatively. In the traditional group, 6 of 16 cases suffered pedicle screw pull out or loosening during placement of the standard rod at the apex vertebrae on the concave side. In three cases, the mono-axial pedicle screws near the apex were abandoned and in five cases replaced with poly-axial pedicle screws. This study shows that the temporary use of SMA rod may reduce the operative time, blood loss, while improve the correction of the coronal plane when compared with standard techniques

Minimally invasive scoliosis surgery: an innovative technique in patients with adolescent idiopathic scoliosis

Minimally invasive spine surgery is becoming more common in the treatment of adult lumbar degenerative disorders. Minimally invasive techniques have been utilized for multilevel pathology, including adult lumbar degenerative scoliosis. The next logical step is to apply minimally invasive surgical techniques to the treatment of adolescent idiopathic scoliosis (AIS). However, there are significant technical challenges of performing minimally invasive surgery on this patient population. For more than two years, we have been utilizing minimally invasive spine surgery techniques in patients with adolescent idiopathic scoliosis. We have developed the present technique to allow for utilization of all standard reduction maneuvers through three small midline skin incisions. Our technique allows easy passage of contoured rods, placement of pedicle screws without image guidance, and allows adequate facet osteotomy to enable fusion. There are multiple potential advantages of this technique, including: less blood loss, shorter hospital stay, earlier mobilization, and relatively less pain and need for pain medication. The operative time needed to complete this surgery is longer. We feel that a minimally invasive approach, although technically challenging, is a feasible option in patients with adolescent idiopathic scoliosis. Although there are multiple perceived benefits, long term data is needed before it can be recommended for routine use

Temporary use of shape memory spinal rod in the treatment of scoliosis

NiTinol shape memory alloy is characterized by its malleability at low temperatures and its ability to return to a preconfigured shape above its activation temperature. This process can be utilized to assist in scoliosis correction. The goal of this retrospective study was to evaluate the clinical and radiographic results of intraoperative use of shape memory alloy rod in the correction of scoliosis. From May 2002 to September 2006, 38 scoliosis patients (ranging from 50° to 120°; 22 cases over 70°) who underwent shape memory alloy-assisted correction in our institute were reviewed. During the operation, a shape memory alloy rod served as a temporary correction tool. Following correction, the rod was replaced by a rigid rod. The mean blood loss at surgery was 680 ± 584 ml; the mean operative time was 278 ± 62 min. The major Cobb angle improved from an average 78.4° preoperatively to 24.3° postoperatively (total percent correction 71.4%). In 16 patients with a major curve <70° and flexibility of 52.7%, the deformity improved from 58.4° preoperatively to 12.3° postoperatively (percent correction, 78.9%). In 22 patients with a major curve >70° and flexibility of 25.6%, the deformity improved from 94.1° preoperatively to 30.1° postoperatively (percent correction, 68.1%). Only one case had a deep infection. There were no neurologic, vascular or correction-related complications such as screw pullout or metal fracture. The study shows that the intraoperative use of a shape memory rod is a safe and effective method to correct scoliosis

Surgical treatment of scoliosis: a review of techniques currently applied

In this review, basic knowledge and recent innovation of surgical treatment for scoliosis will be described. Surgical treatment for scoliosis is indicated, in general, for the curve exceeding 45 or 50 degrees by the Cobb's method on the ground that

Comparison of effectiveness of Halo-femoral traction after anterior spinal release in severe idiopathic and congenital scoliosis: a retrospective study

<p>Abstract</p> <p>Background</p> <p>Halo-femoral traction could gradually improve the coronal and sagittal deformity and restore the trunk balance through the elongation of the spine. The purpose of this retrospective study was to assess the effectiveness of Halo-femoral traction after anterior spinal release in the management of severe idiopathic and congenital scoliosis.</p> <p>Methods</p> <p>Sixty patients with severe and rigid curve treated with anterior spinal release, Halo-femoral traction, and second stage posterior spinal fusion were recruited for this retrospective study. Idiopathic Scoliosis (IS) group was 30 patients (23 females and 7 males) with mean age of 15.5 years. The average coronal Cobb angle was 91.6° and the mean global thoracic kyphosis was 50.6°. The curve type of these patients were 2 with Lenke 1AN, 4 with Lenke 1A+, 1 with Lenke 1BN, 10 with Lenke 1CN, 3 with Lenke 1C+, 3 with Lenke 3CN, 3 with Lenke 3C+, and 4 with Lenke 5C+. Congenital Scoliosis (CS) group included 30 patients (20 females and 10 males) with average age of 15.2 years. The average coronal Cobb angle of the main curve before operation was 95.7° and the average thoracic kyphosis was 70.2°. All patients had a minimum 12-month follow-up radiograph (range 12–72 months, mean 38 months).</p> <p>Results</p> <p>The average traction time was 23 days and the average traction weight was 16 kg. Four patients experienced brachial plexus palsy and complete nerve functional restoration was achieved at two months follow-up. For the IS group, the post-operative mean Cobb angle of major curve averaged 40.1° with correction rate of 57.5%. For the CS group, the post-operative mean Cobb angle was 56.5° with average correction rate of 45.2%. The difference in curve magnitude between the IS and CS patients after posterior correction was statistically significant (t = 4.15, p < 0.001). The correction rate of kyphosis between IS and CS patients was also statistically significant (t = -2.59, p < 0.016).</p> <p>Conclusion</p> <p>Halo-femoral traction was a safe, well-tolerated and effective method for the treatment of severe and rigid scoliosis patients. The posterior correction rate obtained after anterior release and traction was significant superior than that recorded from side bending film in current study.</p