Marc A. Asher

Dual growing rod technique for the treatment of progressive early-onset scoliosis: a multicenter study.

Study Design. A retrospective case review of children treated with dual growing rod technique at our institutions. Patients included had no previous surgery and a minimum of 2 years follow-up from initial surgery. Objectives. To determine the safety and effectiveness of the previously described dual growing rod technique in achieving and maintaining scoliosis correction while allowing spinal growth. Summary of Background Data. Historically, the growing rod techniques have used a single rod and the reported results have been variable. There has been no published study exclusively on the results of dual growing rod technique for early-onset scoliosis. Methods. From 1993 to 2001, 23 patients underwent dual growing rod procedures using pediatric Isola instrumentation and tandem connectors. Diagnoses included infantile and juvenile idiopathic scoliosis, congenital, neuromuscular, and other etiologies. All had curve progression over 10° following unsuccessful bracing or casting. Of 189 total procedures within the treatment period, 151 were lengthenings with an average of 6.6 lengthenings per patient. Analysis included age at initial surgery and final fusion (if applicable), number and frequency of lengthenings, and complications. Radiographic evaluation included measured changes in scoliosis Cobb angle, kyphosis, lordosis, frontal and sagittal balance, length of T1–S1 and instrumentation over the treatment period, and space available for lung ratio. Results. The mean scoliosis improved from 82° (range, 50°–130°) to 38° (range, 13°–66°) after initial surgery andwas 36° (range, 4°–53°) at the last follow-up or post-finalfusion. T1-S1 length increased from 23.01 (range, 13.80–31.20) to 28.00 cm (range, 19.50–35.50) after initial surgery and to 32.65 cm (range, 25.60–41.00) at last follow-up or post-final fusion with an average T1–S1 length increase of 1.21 cm per year (range, 0.13–2.59). Seven patients reached final fusion. The space available for lung ratio in patients with thoracic curves improved from 0.87 (range, 0.7–1.1) to 1.0 (range, 0.79–1.23, P = 0.01). During the treatment period, complications occurred in 11 of the 23 patients (48%), and they had a total of 13 complications. Four of these patients (17%) had unplanned procedures. Following final fusion, 2 patients required extensions of their fusions because of curve progression and lumbosacral pain. Conclusion. The dual growing rod technique is safe and effective. It maintains correction obtained at initial surgery while allowing spinal growth to continue. It provides adequate stability, increases the duration of treatment period, and has an acceptable rate of complication compared with previous reports using the single rod technique.

Adolescent idiopathic scoliosis: natural history and long term treatment effects

Adolescent idiopathic scoliosis is a lifetime, probably systemic condition of unknown cause, resulting in a spinal curve or curves of ten degrees or more in about 2.5% of most populations. However, in only about 0.25% does the curve progress to the point that treatment is warranted.Untreated, adolescent idiopathic scoliosis does not increase mortality rate, even though on rare occasions it can progress to the >100° range and cause premature death. The rate of shortness of breath is not increased, although patients with 50° curves at maturity or 80° curves during adulthood are at increased risk of developing shortness of breath. Compared to non-scoliotic controls, most patients with untreated adolescent idiopathic scoliosis function at or near normal levels. They do have increased pain prevalence and may or may not have increased pain severity. Self-image is often decreased. Mental health is usually not affected. Social function, including marriage and childbearing may be affected, but only at the threshold of relatively larger curves.Non-operative treatment consists of bracing for curves of 25° to 35° or 40° in patients with one to two years or more of growth remaining. Curve progression of ≥ 6° is 20 to 40% more likely with observation than with bracing. Operative treatment consists of instrumentation and arthrodesis to realign and stabilize the most affected portion of the spine. Lasting curve improvement of approximately 40% is usually achieved.In the most completely studied series to date, at 20 to 28 years follow-up both braced and operated patients had similar, significant, and clinically meaningful reduced function and increased pain compared to non-scoliotic controls. However, their function and pain scores were much closer to normal than patient groups with other, more serious conditions.Risks associated with treatment include temporary decrease in self-image in braced patients. Operated patients face the usual risks of major surgery, a 6 to 29% chance of requiring re-operation, and the remote possibility of developing a pain management problem.Knowledge of adolescent idiopathic scoliosis natural history and long-term treatment effects is and will always remain somewhat incomplete. However, enough is know to provide patients and parents the information needed to make informed decisions about management options.

Dual Growing Rod Technique Followed for Three to Eleven Years Until Final Fusion : The Effect of Frequency of Lengthening

Study Design. Retrospective case review of children completing dual growing rod treatment at our institutions. Patients had a minimum of 2 years follow-up. Objective. To identify the factors influencing dual growing rod treatment outcome followed to final fusion. Summary of Background Data. Published reports on dual growing rod technique results for early onset scoliosis demonstrate it to be safe and effective in curve correction and maintenance as well as in allowing spinal growth. Methods. Between 1990 and 2003, 13 patients with no previous surgery and noncongenital curves underwent final fusion. All had preoperative curve progression over 10° after unsuccessful nonoperative treatment. There were 10 females and 3 males. Average age was 6.6 ± 2.9 years at initial surgery. There were 3 idiopathic, 1 nonspine congenital anomaly, and 9 syndromic patients. Analysis included age at initial surgery and final fusion, number and frequency of lengthenings, and complications. Radiographic evaluation included changes in Cobb angle, T1–S1 length, and instrumentation length over the treatment period. Results. Cobb angle improved from 81.0 ± 23° to 35.8 ± 15° postinitial and 27.7 ± 17° after final fusion. Average number of lengthenings was 5.2 ± 3 at an interval of 9.4 ± 5 months. T1–S1 length increased from 24.4 ± 3.4 to 29.3 ± 3.6 cm postinitial and 35.0 ± 3.7 cm postfinal fusion. Average growth was 1.46 ± 0.66 cm/year. Those lengthened at ≤6 months (n = 7; range, 5.5–6.7 months) had a higher annual growth rate of 1.8 cm versus 1.0 cm (P = 0.018) from postinitial to postfinal and significantly greater scoliosis correction (79% vs. 48%, P = 0.007) than those lengthened less frequently (n = 6; range, 9–20 months). Six patients experienced complications: 3 within the treatment period, 2 postfinal, and 1 both during and after treatment. Conclusion. Dual growing rod technique resulted in 5.7 ± 2.9 cm of spinal growth during a 4.37 ± 2.4 year treatment period. There was significantly greater growth and correction achieved in those lengthened more frequently.

Thoracolumbar spinal injuries. A comparative study of recumbent and operative treatment in 100 patients.

Internal fixation of fractures of the thoracolumbar spine with early ambulation is evaluated in this study of 100 patients with 106 fractures, 34 of which were treated by recumbency, 13 with Meurig-Williams plates, and 59 with Harrington rods. Fracture reduction in the recumbent group was 14% unsatisfactory and 82% satisfactory; only one fracture was anatomically reduced. After plating, 38% of fracture reductions were unsatisfactory and 61 % were satisfactory. Harrington rod reduction and internal fixation resulted in 67% anatomic, 31 % satisfactory, and 2% unsatisfactory reductions. Neurologic improvement in partial lesions was 53% with Harrington rods and 44% with recumbent treatment. For paraplegic patients the time between treatment and wheelchair mobilization was reduced from 10.5 weeks with recumbent treatment to 5.3 weeks with Harrington instrumentation. Rehabilitation time for ambulatory candidates was decreased from 7.1 weeks to 2.5 weeks. Complications were reduced from 18% in the recumbent group to 7% in the Harrington rod group. By using the three above-three below, rod long/fuse short approach rather than the two above-two below with fusion over the length of the rods technique, the number of anatomic reductions was increased from 70% to 82% and the length of the fusion decreased from 4.8 levels to 1.4 levels.

Talocalcaneal coalition resection: a 10-year follow-up.

Eight patients (nine feet) who underwent resection of persistently symptomatic talocalcaneal middle-facet coalitions were reevaluated > or = 10 years after surgery. Satisfactory results persisted in eight of nine cases with no deterioration of symptom relief. There was no loss of motion or development of degenerative joint changes. No patient required a secondary surgery. It appears that resection of symptomatic talocalcaneal coalition provides satisfactory results in the majority of patients, and its benefits are maintained 10 years after the procedure.

Pelvic Fixation of Growing Rods Comparison of Constructs

Study Design. Retrospective review. Objective. To analyze outcomes and complications of growing rods fixed to the pelvis. Summary of Background Data. Growing systems with pelvic foundations are used for neuromuscular/syndromic scoliosis. There is little data comparing different constructs. This project analyzed the outcomes and complications of this population. Methods. Records/radiographs of 36 patients from the Growing Spine database with growing rods anchored in the pelvis were studied. Diagnoses included spinal muscular atrophy-6, cerebral palsy-5, myelomeningocele-5, congenital-4, arthrogryposis-1, and miscellaneous/syndromic-15. Age at surgery was 6.8 ± 3 years. Preoperative curve was 86° ± 22° and pelvic obliquity was 27° ± 11°. Follow-up was 40 ± 23 months. Rod breakage rate was compared to that of 299 patients not fixed to the pelvis. Results. Iliac screws were used in 20 patients, iliac rods in 10, S-rods in 3, and sacral fixation in 6. Dual rods were used in 30 patients; single in 6. At follow-up, mean Cobb improved to 48° ± 20° and pelvic obliquity improved to 11° ± 7°. Iliac screws achieved significantly better Cobb and pelvic obliquity correction than sacral fixation (47% vs. 29%, P = 0.04, 66% vs. 40%, P = 0.001). Pelvic obliquity correction exceeded major curve correction (P < 0.001). Total gain in T1–S1 length was 8.6 ± 4.3 cm; gain during lengthenings was 4.0 ± 4.7 cm. Bilateral rods provided better correction of both pelvic obliquity (67% vs. 44%, P = 0.006) and major curve (47% vs. 25%, P = 0.02) than unilateral rods. Six patients have undergone final fusion at mean 3.3 ± 1.8 years after initial surgery. Five patients developed deep infections. There were 6 rod breakages; this rate did not differ from constructs not anchored in the pelvis (P = 0.36). There were 5 breakages of iliac screws and none of other anchors (P = 0.035). Conclusion. Growing rods can include pelvic fixation to correct pelvic obliquity or obtain adequate fixation. Dual iliac fixation provides the best correction. Both iliac screws and rods provide satisfactory distal fixation; iliac screws had a higher rate of breakage. Growing rods with pelvic fixation are effective in deformity correction and achieving growth.

The effect of Harrington rod contouring on lumbar lordosis

The effect of Harrington rod sagittal plane contouring, or lack of it, on total lumbar, segmental lumbar, and lumbosacral lordosis was studied retrospectively in a series of 36 patients operated on for idiopathic scoliosis. Regardless of contouring, there was a decrease in total lumbar lordosis and lordosis above L4, with an increase in lordosis below L5. Although not statistically significant, patients with contoured rods had less loss of segmental (L1–4) lordosis and less increase in segmental lumbosacral lordosis (L4–S1) than the noncontoured group. Although helpful, additional steps beyond concave rod contouring appear to be necessary to consistently preserve lumbar lordosis.

Combined innominate and femoral osteotomy for the treatment of severe Legg-Calvé-Perthes disease.

Nine patients who underwent combined innominate and femoral osteotomy for the treatment of Legg-Calvé-Perthes disease were evaluated. All had Catterall group III or IV involvement, the average number of radiographie “head-at-risk” signs was 3.2, and the average epiphyseal extrusion was 26%. At an average follow-up of 50.5 months, the clinical results were seven good and two fair. The radiographie results were four good, four fair, and one poor. We believe this procedure is indicated in the older patient with severe Perthes disease in whom femoral head subluxation or deformity makes containment difficult or impossible by more conventional methods.

Transverse plane pelvic rotation in adolescent idiopathic scoliosis: primary or compensatory?

Several studies have suggested that the pelvis is involved in the etiology or pathogenesis of adolescent idiopathic scoliosis (AIS). The purpose of this retrospective, cross-sectional radiographic study is to identify any correlation between the transverse plane rotational position of the pelvis in stance and operative-size idiopathic or congenital scoliosis deformities, using Scheuermann’s kyphosis and isthmic spondylolisthesis patients for comparison. The hypothesis tested was that the direction of transverse pelvic rotation is the same as that for a thoracic scoliosis. As a group, AIS patients had a significant transverse plane pelvic rotation in the same direction as the thoracic curve. When subdivided into the six Lenke curve patterns, this was true for the groups with a major thoracic curve: thoracic (1), double thoracic (2) and double curve patterns (3). It was not true for patterns with a major thoracolumbar/lumbar curve: single thoracolumbar/lumbar (5) and double thoracic-thoracolumbar/lumbar (6). Nor was it true for triple (4) curves. The Lenke 1 and 2 major thoracic curves without compensatory thoracolumbar/lumbar curves did not have the predicted pelvic rotation. All congenital scoliosis patients studied had main thoracic curves and significant transverse plane pelvic rotation in the same direction as the thoracic curve. There was no transverse plane pelvic rotation in the Scheuermann’s kyphosis or isthmic spondylolisthesis patients. We interpret these findings as consistent with a compensatory rotation of the pelvis in the same direction as the main thoracic curve in most patients with a compensatory thoracolumbar/lumbar curve as well as in patients with main thoracic congenital scoliosis.

Biomechanical analysis of posterior fixation techniques in a 360° arthrodesis model

Study Design. A biomechanical study to assess the ability of posterior fixation techniques to stabilize a functional spine unit (FSU) after insertion of an anterior load-sharing device. Objective. The objective of this study is to compare various posterior fixation techniques in combination with an anterior load-sharing implant. Summary of Background Data. Pedicle screws and translaminar facet screws have been shown to improve the stiffness of an FSU in combination with an anterior load-sharing device. No published studies, to our knowledge, have compared translaminar facet screw fixation versus bilateral and unilateral pedicle screw fixation used with an anterior load-sharing device. Methods. Ten cadaveric FSUs were potted using methylmethacrylate and attached to a spine simulator mounted to an MTS Mini-Bionix testing machine. The simulator was configured to control compressive loading, axial torque, flexion, extension, and lateral bending. Each specimen was tested in the intact state and following the application of each of four stabilization techniques: custom cage alone, cage plus translaminar facet screw fixation, cage plus unilateral pedicle screw and plate fixation, and cage plus bilateral pedicle screw and rod fixation with transverse coupling. Compressive stiffness and total range of motion (ROM) between ±8 Nm of torque were extracted from the raw data. Results. Each fixation method decreased ROM in torsion, flexion-extension, and lateral bending compared with the intact state. Unilateral pedicle fixation offered less stability than either of the other posterior fixations in all modes of testing except axial loading, where it was equivalent. Translaminar facet screw fixation was equivalent to bilateral pedicle screws in all modes tested. Conclusions. Using a load-sharing interbody implant, translaminar facet screws are equivalent to bilateral pedicle screws in resisting motion in all three planes. Translaminar facet screws and bilateral pedicle screws offer greater stabilization in all three planes compared with unilateral pedicle screws and a single plate.