Selective thoracic surgery in the Lenke type 1A: King III and King IV type curves.

Pedicle screw fixation enables enhanced three-dimensional correction of spinal deformities and effectively shortens the distal fusion level. However, the choice of distal fusion level is still controversial in single thoracic idiopathic scoliosis with the lumbar compensatory curve not crossing the middle line (Lenke type 1 with modifier A or King type III and IV curves).The authors retrospectively analyzed 31 patients treated by segmental pedicular instrumentation alone, affected by a single thoracic adolescent idiopathic scoliosis with a compensatory lumbar curve not crossing the midline (Lenke 1A), with an average age of 16.3 years (range 10-22 years). The patients with regard to the King classification were also assessed. A statistical analysis was performed to determine whether the two groups (King III, King IV) presented differences concerning the level of the stable vertebra (SV), end vertebra (EV), and neutral vertebra (NV) and were also analyzed the results at follow-up regarding the relationships between the SV, EV, and lowest instrumented vertebra (LIV). The statistical analysis showed a significant difference between the two curve types. In the King III type curve the SV, EV, and NV appeared to be more proximal than those of the King IV type curve and the segments between the SV, EV, and NV appeared to be reduced in King III curves compared with King IV curves. At a follow-up of 3.2 years (range 2.2-5) the thoracic curve showed a correction of 58.4% (from 62.3 degrees to 26.6 degrees ) and compensatory lumbar curve an average spontaneous correction of 52.4% (from 38.1 degrees to 18.1 degrees ).The position of the LIV was shorter than the position of the SV in 30 patients (97%) with an average "salvage" of 2.1 (from 1 to 4) distal fusion levels. Four cases (13%), all affected by a King IV type curve, presented at follow-up an unsatisfactory results due to an "adding on" phenomenon. The statistical analysis confirmed that this phenomenon was correlated with The King IV curve (P = 0.043; Chi-square test) and that the only predictive parameter for its onset was the LIV-SV difference (odds ratio = 0.093; with a confidence interval of 0.008-1): every time that in King IV curve type the LIV was three or more levels shorter than the stable vertebra at follow-up the "adding on" phenomenon was present. The authors conclude that Lenke's type 1 with modifier A includes two kinds of curves, King III and King IV and that the Lenke's type 2 curves and King V with the lumbar curve not crossing the middle line have a similar behavior. Therefore, it is of authors' opinion that "the adding on phenomenon" could be prevented by more rigidly defining K. IV versus K. III curves. In Lenke's 1/2 A-K. IV/V type with the rotation of the first vertebra just below the thoracic lower EV in the same direction as the thoracic curve, and when SV and EV show more than two levels of difference, it is necessary to extend the lower fusion down to L2 or L3 (not more than two levels shorter than the SV). Whereas in Lenke's 1/2 A-K. III/V with the rotation of the first proximal vertebra of lumbar curve in the opposite direction to the thoracic apex and when SV and EV show not more than two level gap differences, the position of the lowest instrumented vertebra can be two or three levels shorter than the stable vertebra with satisfactory postoperative spinal balance. Therefore, the stable vertebra and the rotation of lumbar curve are considered to be a reliable guide for selecting the lower level of fusion.

Thoracoplasty in the surgical treatment of adolescent idiopathic scoliosis.

A consecutive series of 40 adolescents surgically treated between 1998-2001, by posterior spinal fusion and thoracoplasty were compared with a similar group of 40 adolescents treated in the same period by posterior only segmental fusion. Clinical and radiographic analysis was performed, including the SRS-30 questionnaire and Pulmonary Function Tests (PFT). Minimum five years follow-up was requested. No statistical differences were found between the two groups in PFT's both pre-operatively and at latest follow up. Our findings suggest that thoracoplasty did not adversely affected long-term PFT's in AIS patients treated by posterior spinal fusion alone.

An innovative diagnostic procedure of vertebral deformities without exposure to X-rays.

The objective of the study was to compare standard manual X-ray measurements of vertebral deformities and values obtained from the Ortelius 800. 52 Patients (41 females and 11 males: mean age 20.35 years) with adolescent vertebral deformities, was studied. The patients were evaluated with standard radiographic views and the Ortelius 800. The parameters considered for the comparison were the angles of scoliosis and kyphosis and the values of global axial deformity, shoulder asymmetry and pelvic tilt. We also evaluated the modification of pelvic/shoulder angle after surgery (this parameter allows to evaluate vertebral rotation and can be derived only from the Ortelius 800). This study allowed us to conclude that there is a perfect agreement between measurements with the Ortelius 800 and those resulting from standard x-rays. The system has also proved to have the capability of quantifying changes in vertebral rotation.