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PubMed1997

Prevalence of segmental wire breakage using Cotrel-Dubousset instrumentation in the management of idiopathic scoliosis.

STUDY DESIGN: This is a retrospective radiographic and medical record analysis of 77 patients. OBJECTIVES: To determine whether there is an increased prevalence of segmental sublaminar wire breakage associated with the knurled (diamond) pattern machined onto the Cotrel-Dubousset rod as opposed to a smooth rod. SUMMARY OF BACKGROUND DATA: Segmental fixation of vertebral segments with sublaminar wires is a common surgical technique, and the use of sublaminar wires with a knurled Cotrel-Dubousset rod theoretically could cause premature wire breakage. METHODS: Sixty-six patients with idiopathic scoliosis had the Cotrel-Dubousset (knurled rod) system and comprised the study group, and the Texas Scottish Rite Hospital system (smooth rod) was placed in 14 patients, who served as a control group. Serial radiographs after 3, 6, 12, and 24 months were reviewed. All patients had augmentation of their scoliosis constructs with 16-gauge sublaminar wires in the lumbar spine. Minimum follow-up period was 24 months. RESULTS: No wire breakage was noted in any patient. CONCLUSIONS: There is no increased likelihood that the knurled rod pattern will cause wire breakage, provided a solid fusion is obtained.

Adolescent↗
PubMed1997

Infantile scoliosis in Marfan syndrome.

STUDY DESIGN: A retrospective review of clinical data was conducted. OBJECTIVES: To determine the characteristics of infantile scoliosis in Marfan syndrome and the response to treatment of patients with this condition. SUMMARY OF BACKGROUND DATA: No previous study has reported the features of this condition nor the effect of treatment on patients with this syndrome. METHODS: The data on all patients seen at one institution who had Marfan syndrome and scoliosis by age three were reviewed. Fourteen of the 600 patients from the group examined who had Marfan syndrome fit the above criteria. Skeletal and general features were studied. RESULTS: Thirteen of the 14 patients had no family history of Marfan syndrome, a finding which does not fit the usual autosomal dominant inheritance pattern. All 14 patients had exaggeration of the Marfan. All but one patient had cardiac valvular insufficiency that required repair by age 11. Thirteen patients had thoracic aortic aneurysm, 10 had lens dislocation, and eight had sternal deformity. Three patients had hip dislocations, two had pyloric stenosis, and two had dural ectasia. Motor delay was evidenced by onset of walking past 18 months in nine patients; three of these patients were never able to walk independently. One patient each died at ages 1, 3, 4, and 8 years; all others have survived to present (mean age, 13 years). The mean curve of the patients' spines at presentation was 38 degrees. Eleven curves were double major, two were thoracolumbar, and one was double thoracic. Brace wear did not halt curve progression in any of the nine patients for whom it was used. Instrumentation without fusion was used in three patients for a mean of 3 years, with best results in one nonkyphotic curve. Nine patients underwent instrumented fusion at a mean age of 6.6 years (range, 3-13 years). Mean curve correction was 51% (from 72 degrees to 34 degrees). Final mean curve was 54 degrees for a mean correction of 20% at the 5-year (average, 5.4 years) follow-up examination. Acute complications occurred in three patients, and five patients needed a second surgery for late complications. Causes for curve increase after surgery included growth and loss of fixation. CONCLUSIONS: In this most severe form of Marfan syndrome, bracing has a limited role and is only to be used if the curve is less than 40 degrees. Surgery should not be performed on a patient younger than four years of age because many patients with large curves before this age will succumb spontaneously to cardiac complications. Instrumentation without fusion should be considered only for patients with no significant kyphosis. Results of fusion are better for patients who are older than five years of age.

Adolescent↗
PubMed1999

The spinal curve in standing and sitting postures in children with idiopathic scoliosis.

STUDY DESIGN: A sample of convenience of children with moderate idiopathic scoliosis without bracing or surgery was studied. The sample consisted of 19 children, aged 9 to 16 years, with mean Cobb angle of 24 degrees. The spinal configurations and paraspinal muscle activity in several commonly assumed postures were examined. OBJECTIVES: To determine how the apex angles, verticality of spine, and muscle activity vary with the assumed posture and whether the location and the number of spinal curves affect these variables. SUMMARY OF BACKGROUND DATA: It has been suggested that the configuration of the spine in commonly assumed postures can affect the spinal curve in scoliosis because of gravitational bending moments. There is, however, a paucity of data obtained in subjects in sitting postures that school-age children assume daily for prolonged periods. Absence of bilateral symmetry in pressure during sitting has been described, but its effect on the spinal apex angle has not been investigated. METHODS: Infrared-emitting markers, whose three-dimensional positions could be tracked by a pair of cameras, were affixed to the spine. The natural postures studied were relaxed standing, relaxed sitting, erect sitting, and writing while seated. Electromyographic activity in muscles close to the spinal apexes was recorded bilaterally for each test posture. RESULTS: Subjects leaned laterally and, in general, anteriorly, in all test postures, rather than placing the C7 vertebra vertically above S1. The direction of lean and the change in the spinal apex angle from standing to sitting varied depending on whether the spinal curve was single or double, thoracic or lumbar. Subjects with single curves, whether thoracic or lumbar, tended to lean laterally toward the convexity of their curve apex--that is, the lean was in a direction that reduced the apex angle. Subjects with double curves (thoracic and lumbar), in all postures except relaxed sitting, tended to lean toward the convexity of the lumbar curve, thereby reducing the lumbar apex angle and exacerbating the thoracic angle. Most subjects' apex angles were smaller in relaxed or erect sitting than in relaxed standing. Electromyographic activity was in general greater on the convex side of the curve, with greatest activity in erect sitting. CONCLUSIONS: The findings indicate that in self-selected postures the gravitational effect of leaning and the muscle activity in paraspinal muscles may serve to reduce the apex angle. Thus, a fully upright, centered posture may not be best for correction of every patient's spinal curve.

Activities of Daily Living↗
PubMed1999

Comparison of anterior and posterior instrumentation for correction of adolescent thoracic idiopathic scoliosis.

STUDY DESIGN: This was a prospective study of two cohort groups of patients (one group receiving anterior instrumentation and the other posterior instrumentation) receiving treatment for thoracic idiopathic scoliosis. OBJECTIVE: To present the 2-year postoperative results of a prospective multicenter study comparing the use of anterior instrumentation with that of posterior multisegmented hook instrumentation for the correction of adolescent thoracic idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Despite reports of satisfactory results, problems have been reported with posterior systems, including worsening of the lumbar curve after surgery and failure to correct hypokyphosis. Theoretically, the advantages of anterior instrumentation include prevention of lumbar curve decompensation by shortening the convexity of the thoracic curve. In addition, by removing the disc, better correction of thoracic hypokyphosis could be obtained. METHODS: Seventy-eight patients who underwent an anterior spinal fusion using flexible threaded rods and nuts (Harms-MOSS instrumentation, De Puy-Motech-Acromed, Cleveland, OH) were analyzed and compared with 100 patients who underwent posterior spinal fusion with multisegmented hook systems. Parameters of comparison included coronal and sagittal correction, balance, distal lumbar fusion levels, and complication. All patients had idiopathic thoracic curves of King Types II to V. The average age at surgery was 14 years in each group, the average preoperative curve 57 degrees, and the minimum duration of follow-up for all patients 24 months. All data were collected prospectively and analyzed via Epl into statistical analysis (Centers of Disease Control, Atlanta, GA). RESULTS: Average coronal correction of the main thoracic curve was 58% in the anterior group and 59% in the posterior group (P = 0.92). Analysis of sagittal contour showed that the posterior systems failed to correct a preoperative hypokyphosis (sagittal T5 to T12 less than 20 degrees) in 60% of cases, whereas 81% were normal postoperatively in the anterior group. However, hyperkyphosis (sagittal T5 to T12 greater than 40 degrees) occurred after surgery in 40% of the anterior group when the preoperative kyphosis was greater than 20 degrees. Postoperative coronal balance was equal in both groups. An average of 2.5 (range, 0-6) distal fusion levels were saved using the anterior spinal instrumentation according to the criteria used for determining posterior fusion levels in this study. Selective fusion of the thoracic curve (distal fusion level T11, T12, L1) was performed in 76 of 78 patients (97%) in the anterior group as compared with only 18 of 100 (18%) in the posterior group. Surgically confirmed pseudarthrosis occurred in 4 of 78 patients (5%) in the anterior group and in 1 of 100 patients (1%) in the posterior group (P = 0.10). Loss of correction greater than 10 degrees occurred in 18 of 78 patients (23%) in the anterior group and in 12 of 100 patients (12%) in the posterior group (P = 0.01). Implant breakage occurred in 24 patients (31%) of the anterior group and in only 1 patient (1%) of the posterior group. CONCLUSIONS: 1) Coronal correction and balance were equal in both the anterior and posterior groups, even though the anterior group had the majority of curves (97%) fused short or to L1, whereas only 18% were fused short or to L1 in the posterior group. 2) In the anterior group there was a better correction of sagittal profile in those with a preoperative hypokyphosis less than 20 degrees. However, hyperkyphosis (with a mean of 54 degrees) occurred in 40% of those in the anterior group with a preoperative kyphosis of more than 20 degrees. 3) An average of 2.5 lumbar levels can be saved with anterior fusion and instrumentation according to the criteria used for choosing posterior fusion levels in this study. 4) Using the 3.2-mm flexible rod in this study, loss of correction, pseudarthrosis, and rod breakage were unacceptably highe

Adolescent↗
PubMed1999

Variability of strap tension in brace treatment for adolescent idiopathic scoliosis.

STUDY DESIGN: A mechanical evaluation of brace strap tensions to document their variability in different patient positions and to assess their biomechanical effectiveness. OBJECTIVES: To measure the strap tensions at which adolescents with scoliosis are wearing their braces and to determine the variations in strap tension in different patient positions. SUMMARY OF BACKGROUND DATA: The biomechanical action of thoracolumbosacral orthoses in still not well understood, and there is no standardized strap tension at which the brace should be fastened to obtain optimal results. METHODS: This study was conducted in 34 adolescents with idiopathic scoliosis wearing thoracolumbosacral orthoses. Brace straps were instrumented with load cells and tightened at four tensions (the ones prescribed by their treating physician and three standardized values: 20, 40, and 60 N). In each case, the tension was recorded while the patients assumed nine positions corresponding to normal daily tasks. The variability of strap tension was evaluated by comparing the changes from the original standing position. RESULTS: The prescribed tensions measured in thoracic and pelvic straps were markedly variable. The greatest changes in tension occurred when the patients were lying down. Relaxation of strap tension was found when the patients returned to the standing position after having completed the tasks. CONCLUSIONS: If strap tension affects the biomechanical actions of the brace, these results indicate that regular brace strap tension adjustments are needed and raise questions about the efficacy of nighttime bracing to correct spinal deformities.

Adolescent↗
PubMed1999

Process measures and patient/parent evaluation of surgical management of spinal deformities in patients with progressive flaccid neuromuscular scoliosis (Duchenne's muscular dystrophy and spinal muscular atrophy).

STUDY DESIGN: Fifty-four consecutive patients with flaccid neuromuscular scoliosis (33 with Duchenne's muscular dystrophy, 21 with spinal muscular atrophy) who had undergone surgery for their disorder between 1985 and 1995 were sent questionnaires to evaluate function, self-image, cosmesis, pain, pulmonary status, patient care, quality of life, and satisfaction. Forty-eight patients returned the questionnaires. OBJECTIVE: To assess patient/parent satisfaction and clinical/functional ways in which spinal fusion helped or did not benefit these patients and to assess complications and the ultimate radiographic result. SUMMARY OF BACKGROUND DATA: There are only a few reports of results of spinal fusion and segmental instrumentation for flaccid neuromuscular disorders. There are no published reports regarding patient/parent evaluation of the procedure. METHODS: Results of the questionnaire were tallied, graded, and divided into eight categories. The questionnaire was validated by a Cronbach's alpha analysis, a test-retest, and a comparison with questionnaire answers from patients with idiopathic scoliosis. Radiographic data and complications also were accumulated. The follow-up periods after surgery ranged from 2 to 12.6 years (average, 7.8 years). RESULTS: Except for two patients who died within 3 months of surgery, all patients seemed to have benefited from the surgery. Cosmesis, quality of life, and overall satisfaction rated the highest. CONCLUSION: These data indicate that spinal fusion with segmental spinal instrumentation benefits most patients with Duchenne's muscular dystrophy or spinal muscular atrophy with spinal deformities in terms of all categories assessed, even though these diseases have a progressively deteriorating course.

Adolescent↗
PubMed1999

Kinematics of the chest cage and spine during breathing in healthy individuals and in patients with adolescent idiopathic scoliosis.

STUDY DESIGN: The lung function test by a Plethysmograph enabled calculations to be made of the total lung capacity and vital capacity. A Motion Analysis System (Elite, BTS Inc., Milano, Italy) was used to observe and record chest cage and spinal movements and as to correlate lung function with the chest cage and spine kinematics. OBJECTIVES: To determine the three-dimensional kinematics and the shape and size changes of the chest cage and thoracic spine motion during deep breathing in healthy and scoliotic individuals. SUMMARY OF BACKGROUND DATA: Lateral flexion plus rotation of the involved vertebrae around a vertical axis causing a decrease in lung function is the main disfigurement of scoliosis. Reports show that even after spinal fusion, reduced vital capacity associated with an increased residual volume are detected. Factors such as angle of scoliosis, length of the spinal column involved, and duration of the deformity influence pulmonary function but do not significantly affect its reduction. Mechanical inefficiency during breathing has not been studied. METHODS: Three-dimensional kinematics of the chest cage and spine during breathing were studied in 41 scoliotic patients and in 20 healthy individuals. Three-dimensional chest cage motions relative to the spine and thoracic spine motions relative to T12 were calculated. To examine stiffness of the spine, lateral bending angles were calculated. The lung function test, which including spirometry and lung subdivision, also was performed for the scoliotic patients. RESULTS: Significant differences (P < 0.05) were found in the movements of the upper level of the chest cage in anteroposterior and vertical directions, ranging from 16.7 to 28.6 mm in healthy individuals and from 12.1 to 24.2 mm in scoliotic patients. The thoracic spine displayed two-dimensional movements posteriorly and vertically during breathing, whereas less movement was seen in scoliotic patients. In addition, overall the scoliotic spine showed signs of stiffness in lateral bending. CONCLUSIONS: The range of movement of the chest cage and spine is more limited in the scoliotic cases. This overall stiffness of the chest cage and the spine may contribute to the mechanical inefficiency and impairment of pulmonary function found in scoliotic patients.

Adolescent↗
PubMed1999

Maintaining lumbar lordosis with anterior single solid-rod instrumentation in thoracolumbar and lumbar adolescent idiopathic scoliosis.

STUDY DESIGN: A prospective radiographic evaluation of 20 consecutive patients with primary lumbar or thoracolumbar adolescent idiopathic scoliosis who were treated with anterior convex compressive single solid-rod spinal instrumentation and structural titanium mesh (Harms) cages. OBJECTIVES: To evaluate a lordosis-preserving anterior single solid-rod instrumented fusion technique for these specific adolescent idiopathic curves. SUMMARY OF BACKGROUND DATA: Maintaining instrumented segmental lumbar lordosis after anterior fusion and instrumentation for thoracolumbar and lumbar curves has been difficult. Twenty consecutive patients who underwent anterior single solid-rod fusion, aged 18 or younger with a primary thoracolumbar or lumbar curve, were observed for preservation of lordosis for a minimum of 2 years. METHODS: All patients underwent an identical anterior surgical technique, involving discectomies and anulectomies of all convex discs, structural titanium mesh (Harms) cages placed in the anterior half of all disc spaces below T12, morselized rib autograft packed in all disc spaces to be fused and inside the cages, and anterior single solid-rod (5.0-mm or 5.5-mm diameter) convex compressive spinal instrumentation with appropriate lordotic rod contour and rod rotation as necessary. The anterior rod was placed just posterior to the cages to optimize lordotic contouring of the spine during compression. None of the patients was braced after surgery. The lowest instrumented vertebrae (LIV) were L2 (n = 3), L3 (n = 15), and L4 (n = 2), typically the lower end vertebra of the Cobb measurement. RESULTS: Measurements for the primary coronal Cobb before surgery, 1 week after surgery, and 2 years after surgery were 48 degrees, 11 degrees, and 12 degrees; for C7 plumb line deviation from the midline: 3.6 cm, 1.9 cm, and 1.2 cm; for lowest instrumented vertebra translation: 31 mm, 15 mm, and 15 mm; and for LIV tilt: 29 degrees, 6 degrees and 6 degrees, respectively. Sagittal measurements before surgery, 1 week after surgery, and 2 years after surgery were: T12-L2: -1 degree, -6 degrees, and -6 degrees; T12-LIV: -8 degrees, -13 degrees, -9 degrees; T12-S1: -61 degrees, -56 degrees, -60 degrees; and entire instrumented levels: -6 degrees, -9 degrees, and -6 degrees, respectively. Coronal plane correction improved: 75% in the primary Cobb, 66% in the plumb line, 50% in LIV translation, and 80% in LIV tilt. Sagittal plane alignment improved in T12-L2 lordosis (P < 0.01) with preservation of physiologic lordosis in the instrumented levels, T12-LIV, and T12-sacrum. There were no instrumentation failures, pseudarthroses, or reoperations. CONCLUSIONS: Coronal plane correction with preservation of thoracolumbar and lumbar lordosis 2 years after anterior convex compressive spinal instrumentation was accomplished using a lordotically contoured single solid rod with structural cages placed anteriorly in the disc spaces of patients with primary thoracolumbar or lumbar adolescent idiopathic scoliosis.

Adolescent↗
PubMed1999

The selection of fusion levels using torsional correction techniques in the surgical treatment of idiopathic scoliosis.

STUDY DESIGN: This is a retrospective, consecutive case series, with the index patient included. OBJECTIVES: To evaluate the evolution and effectiveness of instrumentation techniques designed to untwist the scoliosis deformity. SUMMARY OF BACKGROUND DATA: Three-dimensional studies of the idiopathic scoliosis deformity are consistent with the theory that the deformity or deformities evolve as an imperfect torsion or torsions. METHODS: From 1989 through 1995, 102 consecutive patients (84 females, 18 males) underwent surgery with increasing emphasis on torsional correction. One hundred patients (98%), with an average age of 14.3 years (range, 10.5-20.8 years), were observed for an average of 40 months (range, 24-81 months). The upper instrumented vertebra evolved to be the centered vertebra. The lower instrumented vertebra was chosen based on its ability to become horizontal on contralateral bend radiographs and was termed the caudal foundation vertebra. Because these techniques evolved over the first 3 years of the study period, a split analysis was performed to evaluate improvements in correction and correction maintenance over the course of the study. RESULTS: The average Cobb angle was 59 degrees before surgery, 18 degrees after surgery (69% correction), and 22 degrees (63% correction) at latest follow-up. A comparison of the first half of the series with the second half showed no significant demographic differences. Curve correction was significantly improved for King-Moe IIB (thoracolumbar-lumbar curve only), King-Moe III, and King-Moe V curve types in the second half of the series. In the last 4 years, curve correction at latest follow-up for King-Moe IIB curves was 61% for the thoracic curve and 65% for the thoracolumbar-lumbar curve. King-Moe III curves had a 68% correction, and King-Moe V curves had a 50% high thoracic and a 72% thoracic curve correction. Thoraco-lumbar, lumbar, and King-Moe I curves averaged 81% correction of the thoracolumbar-lumbar curve. The angle of thoracic curve inclination improvement at 1 year was maintained at latest follow-up. CONCLUSIONS: This method of selecting instrumentation levels while using torsional correction techniques is safe and reliable. The results were improved with the evolution of these techniques and appear to provide improved correction and correction maintenance compared with that of historical controls.

Adolescent↗
PubMed1999

Late-developing infection in instrumented idiopathic scoliosis.

STUDY DESIGN: This is a retrospective review of all patients requiring either Cotrel-Dubousset or Moss Miami rod removal. All initial spinal instrumentations were for adolescent idiopathic scoliosis from 1985 through 1994. Twenty-two patients who underwent rod removal for late-developing infection constitute the study group. OBJECTIVES: To determine the bacteriology and treatment of patients with late-developing infection after posterior spinal instrumentation for scoliosis. SUMMARY OF BACKGROUND DATA: There have been conflicting reports regarding this entity, some reporting a high percentage of positive cultures and others a low yield. The latter have attributed the entity to fretting corrosion. Much literature describes late appearance of infection with large foreign bodies (implants). Glycocalyx, a membrane that surrounds bacteria adjacent to surgical implants, results in poor antibiotic penetration, poor macrophage action, and difficulty in culturing bacteria. METHODS: One thousand two hundred forty-seven patients who underwent posterior instrumentation from 1985 through 1994 were reviewed. Those requiring implant removal were further studied. Those with late-developing infection (more than 1 year after the initial procedure) were further reviewed. Culture reports, presence of pseudarthrosis, and antibiotic regimen after implant removal were the primary parameters studied. RESULTS: Twenty-two patients (1.7%) experienced development of late infection a mean of 3.1 years after the initial procedure. In specimens from these patients cultured only 72 hours, only 1 of 10 was positive. Of those cultured for 7-10 days (the last 12) 11 were positive, usually for low-virulence skin organisms. After surgery, patients received antibiotics parenterally for 48 hours and orally for 7 days. All wounds were closed primarily. Four patients had pseudarthroses, two underwent revised procedures with titanium implants without signs of infection at more than 2 years' follow-up. CONCLUSIONS: Late-appearing infection with spinal instrumentation can be treated with device removal, primary skin closure, and short-term oral antibiotics. The infections affect soft tissue, not the bone.

Adolescent↗
PubMed1999

Intraoperative comparison of two instrumentation techniques for the correction of adolescent idiopathic scoliosis. Rod rotation and translation.

STUDY DESIGN: A prospective and controlled comparative study of two instrumentation techniques used for the correction of adolescent idiopathic scoliosis. OBJECTIVE: To measure the three-dimensional intraoperative correction obtained with a rotation maneuver as compared with that obtained with a translation maneuver of the first instrumentation rod inserted to determine the difference, if any, in the two techniques for achieving three-dimensional correction. SUMMARY OF BACKGROUND DATA: Adequate three-dimensional correction of scoliotic deformities has been reported with the Cotrel-Dubousset instrumentation using the rod-rotation maneuver. More recently, however, authors of studies with newer instrumentation systems have claimed that better correction can be obtained using a translation technique. So far, no report has clearly demonstrated the three-dimensional changes obtained with this more recent instrumentation technique. METHODS: The changes in position of thoracic and lumbar vertebrae exposed during surgery were documented using a three-dimensional magnetic digitizer in 70 adolescents with idiopathic scoliosis undergoing correction by a posterior approach. Vertebral positions were measured intraoperatively before and after the surgical maneuver in 39 patients with the Cotrel-Dubousset instrumentation (rod rotation) and in 31 patients with the Colorado instrumentation (translation). RESULTS: In both groups, adequate three-dimensional correction of the scoliotic deformities was documented, with significant changes in the frontal and sagittal planes and in the orientation of the plane of maximum deformity for thoracic and lumbar curves. On the other hand, no significant differences were documented between the two procedures except in the frontal plane where a tendency for greater correction was observed for thoracic curves with the translation technique. CONCLUSIONS: The two instrumentation techniques are equally able to achieve a comparable and effective three-dimensional correction of the scoliotic deformities. The use of either a rotation maneuver or a translation technique during surgery does not result in any significant measurable difference in three-dimensional correction.

Adolescent↗
PubMed1999

Recovery from exercise-induced desaturation in the paraspinal muscles in idiopathic scoliosis.

STUDY DESIGN: A study using near-infrared light spectroscopy to measure recovery from exercise-induced desaturation in the paraspinal muscles of patients with idiopathic scoliosis. OBJECTIVES: To measure oxygenation of the paraspinal muscles and obtain differences between the convex and concave sides. SUMMARY OF BACKGROUND DATA: Authors of previous studies have reported that some patients experience pain on the convex side of the paraspinal muscles. The muscles on the convex side are more stretched and stressed than those on the concave side. The current authors investigated the degree of stress by measuring oxygenation and blood volume changes. METHODS: Paraspinal muscle spectral properties at L3 were investigated using near-infrared light spectroscopy. Thirty-six patients (8 men and 28 women) underwent this procedure. To assess a level of peripheral adaptations to exercise, the half-time of Oxyhemoglobin/Myoglobin recovery was measured, which indicates the recovery from energy deficit after exercise. RESULTS: The average half-time recovery on the convex side was 3.38 seconds (range, 1.5-5.5 seconds), whereas that on the concave side was 1.51 seconds (range, 0.7-4.0 seconds). The average difference between the convex side and the concave side was 1.87 seconds (range, 0.9-3.5 seconds). CONCLUSIONS: Half-time recovery on the convex side in the patients with idiopathic scoliosis was slower than that in healthy adults (P < 0.05). Half-time recovery on the concave side in such patients was faster than that on the convex side (P < 0.01). The authors consider half-time recovery an indication of back muscle stress.

Adult↗
PubMed2000

A three-dimensional radiographic comparison of Cotrel-Dubousset and Colorado instrumentations for the correction of idiopathic scoliosis.

STUDY DESIGN: A prospective clinical study comparing two instrumentation systems for the correction of idiopathic scoliosis. OBJECTIVES: To measure the short-term three-dimensional changes in the shape of the spine after corrective surgery and compare the Cotrel-Dubousset instrumentation to the more recent Colorado instrumentation to determine whether one system provides better three-dimensional correction. SUMMARY OF BACKGROUND DATA: Adequate three-dimensional correction of scoliotic deformities has been reported with the Cortrel-Dubousset instrumentation system. During the past decade, a new generation of more versatile and user-friendly spinal implants has appeared, but there are no reports available to indicate whether similar or better correction can be obtained with these newer systems. METHODS: The three-dimensional geometry of the thoracic and lumbar spine was documented in the standing position using a three-dimensional reconstruction technique based on multiplanar radiography in 67 adolescents with idiopathic scoliosis undergoing correction by a posterior approach. Changes in spinal shape were measured 3 days before and 1 month after the surgery in 31 patients with Cotrel-Dubousset instrumentation and 36 patients with Colorado instrumentation. RESULTS: In both groups, adequate three-dimensional correction of the scoliotic deformities was documented for thoracic and lumbar curves, with significant changes in the frontal plane, in the plane of maximum curvature, and in its orientation. When comparing both groups, better correction was obtained in the frontal plane with the Colorado instrumentation (65% vs. 48% with Cotrel-Dubousset), a finding that may be explained by the significantly greater proportion of pedicle screws used in this group. CONCLUSION: Both instrumentation techniques achieve an effective and comparable three-dimensional correction of the scoliotic deformities.

Adolescent↗
PubMed2000

Quantifying changes in standing body segment alignment following spinal instrumentation and fusion in idiopathic scoliosis using an optoelectronic measurement system.

STUDY DESIGN: Longitudinal case studies before and after posterior spinal instrumentation and fusion (PSIF) in idiopathic scoliosis (IS). OBJECTIVES: To quantitate the changes in body segment alignment following PSIF using standard radiographic techniques and an optoelectronic measurement system. SUMMARY OF BACKGROUND DATA: Evaluation of surgical correction following PSIF is traditionally performed radiographically. Radiographic film cannot reliably document transverse and coronal plane pelvic, torso, and shoulder orientation resulting from the global effect of vertebral malalignment. METHODS: Thirty-three subjects with IS were evaluated radiographically and with an optoelectronic measurement system before and 13 months after PSIF. All subjects had a primary right thoracic curve pattern. Thirteen subjects without scoliosis were evaluated as controls. Symmetry measures and transverse and frontal plane orientation relationships were measured and compared preop, postop, and with controls. RESULTS: The major curve decreased from 60 degrees to 24 degrees after surgery. The magnitude of C7 decompensation from the sacrum decreased following PSIF. Control subjects demonstrated neutral coronal and transverse plane alignment. Preoperatively, patients had an elevated and protracted right shoulder. Postoperative data showed correction in both the coronal and transverse planes. Ten out of 33 subjects were within 5 degrees of neutral shoulder protraction before surgery. Twenty-six out of 33 were within 5 degrees of neutral following surgery. CONCLUSIONS: Optoelectronic measurement of body segment alignment may be a useful noninvasive technique in the evaluation of scoliotic deformity. This is a new method of evaluating the global effect of vertebral malalignment on body segment alignment and can be used to quantify changes following PSIF.

Adolescent↗
PubMed2000

Reoperation after primary posterior instrumentation and fusion for idiopathic scoliosis. Toward defining late operative site pain of unknown cause.

STUDY DESIGN: Retrospective case series. OBJECTIVES: To determine the frequency and categorize the indications for reoperation in three implant systems (Harrington, Cotrel-Dubousset [C-D], and Isola). To define late operative site pain (LOSP) of no apparent cause as an indication for implant removal and determine the success of implant removal in relieving LOSP. SUMMARY OF BACKGROUND DATA: Late operative site pain of no apparent cause has been discussed briefly in the literature but has not been investigated as a major indication for implant removal. METHODS: One hundred eighty-two of 190 consecutive patients with idiopathic scoliosis (96%) who underwent primary surgery between January 1, 1981, and December 31, 1992, by one surgeon in one hospital, with use of Harrington, C-D, or Isola instrumentation were studied an average of 9 years after surgery to determine the indications for and frequency of reoperation. RESULTS: The overall frequency of reoperation for all instrumentation types combined was 19%: Harrington, 19%; C-D, 24%; and Isola, 14%. By 6 years' follow-up the cumulative risk of reoperation by Kaplan-Meier analysis was Harrington, 14%; C-D, 21%; and Isola, 14%. (statistically nonsignificant difference). The most frequent indication for reoperation was LOSP of no apparent cause: 8% (14 patients) for all instrumentation types combined. The average interval between the initial operation and reoperation for LOSP was 46 months (range, 20-97 months). The frequency of each implant type was Harrington, 6%; C-D, 12%; and Isola, 6%. By 6 years' follow-up, the cumulative Kaplan-Meier risk for reoperation due to LOSP was Harrington, 5%; C-D, 13%; and Isola, 8% (statistically non-significant difference). Of the 14 patients who had instrumentation removal for LOSP, 10 (71%) had successful relief of pain after implant removal. CONCLUSIONS: Occurring regardless of implant type, LOSP of no apparent cause after posterior instrumentation of scoliosis is a distinct clinical entity and is relieved by implant removal in most patients.

Adolescent↗
PubMed2000

A synthetic porous ceramic as a bone graft substitute in the surgical management of scoliosis: a prospective, randomized study.

STUDY DESIGN: A prospective randomized study. OBJECTIVES: To assess the clinical and radiologic performances of a synthetic ceramic as a bone graft substitute in scoliosis surgery. SUMMARY OF BACKGROUND DATA: Surgery on the skeleton frequently requires harvesting of autogenous bone grafts from the pelvis, but this procedure often is complicated by problems. METHODS: Fifty-eight patients with idiopathic scoliosis, ages 13 to 25 years, were treated by posterior correction and arthrodesis using Cotrel-Dubousset instrumentation. Posterior spinal fusion was performed using local bone grafts combined with autogenous iliac bone grafts in 30 patients, and combined with porous biphasic calcium phosphate ceramic blocks comprising hydroxyapatite and tricalcium phosphate in another 28 patients. The patients were observed for a minimum of 24 months after surgery, with a mean postoperative observation time of 48 months. The results were assessed clinically and radiographically. RESULTS: Patients in the ceramic group had a lower average blood loss than those in the iliac graft group. They also were free from postoperative local complications in the iliac region, which were experienced by a significantly high proportion of patients belonging to the iliac graft group. Radiography demonstrated successful incorporation of the ceramic blocks within 12 months. The correction of the deformity was maintained similarly and satisfactorily in both groups. CONCLUSIONS: These results justify and favor the use of calcium phosphate ceramics as bone graft substitutes for instrumented posterior spinal fusion in teenagers and young adults. Potentially hazardous harvesting of pelvic bone is no longer necessary for such operations.

Adolescent↗
PubMed2000

Femoral artery ischemia during spinal scoliosis surgery detected by posterior tibial nerve somatosensory-evoked potential monitoring.

STUDY DESIGN: A case report of unilateral leg ischemia caused by femoral artery compression detected using posterior tibial nerve somatosensory-evoked potentials during spinal scoliosis instrumentation surgery. OBJECTIVES: To report a rare cause of intraoperative unilateral loss of all posterior tibial nerve somatosensory-evoked potential waveforms. SUMMARY OF BACKGROUND DATA: Failure to obtain adequate popliteal fossa, spinal, subcortical, and cortical potentials during posterior tibial nerve somatosensory-evoked potential spinal cord monitoring usually results from technical factors or chronic conditions affecting the peripheral nerve. METHODS: A 16-year-old boy with thoracic scoliosis had normal posterior tibial nerve somatosensory-evoked potentials both before surgery and in the operating room immediately after anesthesia induction and prone positioning on a four-post spinal frame. RESULTS: One hour after the start of surgery, a minimal amplitude reduction of the right popliteal fossa potentials appeared. Fifteen minutes later, the amplitudes of the popliteal fossa, subcortical, and cortical potentials evoked by right posterior tibial nerve stimulation became substantially reduced. Subsequently, all waveforms were lost. Malfunction of the right posterior tibial nerve stimulator was initially suspected, but when proper function was verified, a search for other causes of this loss led to discovery of leg ischemia. The patient was repositioned on the spinal frame, and all posterior tibial nerve somatosensory-evoked potentials waveforms began to reappear 7 minutes later. There was no postoperative clinically detectable complication. CONCLUSIONS: Although technical malfunction should always be suspected when all intraoperative somatosensory-evoked potential waveforms are initially seen and subsequently lost, one should also consider the possibility that intraoperative ischemia due to limb positioning could be the etiology.

Adolescent↗
PubMed2000

A comparison of single-rod instrumentation with double-rod instrumentation in adolescent idiopathic scoliosis.

STUDY DESIGN: A consecutive series of patients with idiopathic scoliosis treated with single-rod instrumentation was followed prospectively. Outcomes were compared with results obtained from a retrospective review of a consecutive series of patients treated with double-rod instrumentation. OBJECTIVE: To compare single-rod instrumentation with segmental fixation with double-rod instrumentation for the treatment of adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Mechanical testing of single-rod instrumentation with segmental fixation at every level showed it to be as resistant to torsion as a double-rod construct. A clinical trial was initiated to document the clinical outcome in single-rod patients. METHODS: A total of 43 of 51 consecutive patients underwent spinal fusion with a single rod. Outcome was evaluated at a minimum of 2 years after surgery. The control group comprised 103 patients who had standard double-rod instrumentation at the same institution. RESULTS: The single- and double-rod groups were similar with respect to age, sex, curve type, length of follow-up, curve magnitude, and best bend. For King III-V curves undergoing posterior spinal fusion, there was significantly less blood loss in the single-rod group (703 mL vs 1011 mL), less cell saver collection (189 mL vs 367 mL), and less operating time (220 minutes vs 260 minutes). Blood loss and operating time were not different for patients with King I and King II curves. There were eight patients (19%) requiring reoperation because of hardware-related problems in the single-rod group compared with four (4%) in the double-rod group. There were nine patients (21%) with broken rods in the single-rod group, six of whom were symptomatic and five of whom required reoperation. Two patients required multiple operations because of pseudarthrosis in the single-rod group. There were no broken rods in the double-rod group. The single-rod group had 2 early postoperative infections and no late infections compared with 10 late infections in the double-rod group. There was a statistically significant relationship between hardware problems and fusion below L1 in the single-rod group. CONCLUSION: Because of rod failure, single-rod instrumentation should be considered only in curves that can be instrumented to L1 and higher.

Adolescent↗