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Study Design: Early detection of progressive adolescent idiopathic scoliosis (AIS) was assessed based on 3D quantification of the deformity., Objective: Based on 3D quantitative description of scoliosis curves, the aim is to assess a specific phenotype that could be an early detectable severity index for progressive AIS., Summary of Background Data: Early detection of progressive scoliosis is important for adapted treatment to limit progression. However, progression risk assessment is mainly based on the follow up, waiting for signs of rapid progression that generally occur during the growth peak., Methods: Sixty-five mild scoliosis (16 boys, 49 girls, Cobb Angle between 10 and 20°) with a Risser between 0 and 2 were followed from their first examination until a decision was made by the clinician, either considering the spine as stable at the end of growth (26 patients) or planning to brace because of progression (39 patients). Calibrated biplanar x-rays were performed and 3D reconstructions of the spine allowed calculating six local parameters related to main curve deformity. For progressive curve 3D phenotype assessment, data were compared with those previously assessed for 30 severe scoliosis (Cobb Angle > 35°), 17 scoliosis before brace (Cobb Angle > 29°) and 53 spines of nonscoliosis subjects. A predictive discriminant analysis was performed to assess similarity of mild scoliosis curves either to those of scoliosis or nonscoliosis spines, yielding a severity index (S-index). S-index value at first examination was compared with clinical outcome., Results: At the first exam, 53 out of 65 predictions (82%) were in agreement with actual clinical outcome. Approximately, 89% of the curves that were predicted as progressive proved accurate., Conclusion: Although still requiring large scale validation, results are promising for early detection of progressive curves., Level of Evidence: 2.

Background: Rod migration into the spinal canal after posterior instrumented fusion is a rare complication causing late-onset neurological symptoms. The purpose of the present study is to report a case of a 13-year-old boy with spastic cerebral palsy and related neuromuscular kyphoscoliosis who developed late-onset neurological deterioration secondary to progressive implant migration into the spinal canal over a 5-year period., Methods: A decision was made to remove both rods to achieve decompression. Intraoperative findings were consistent with information gained from preoperative imaging. The rods were found to have an intracanal trajectory at T9-T10 for the right rod and T12-L2 for the left rod., Results: The cause of implant migration, with progressive laminar erosion slow enough to generate a solid mass behind, was progressive kyphosis in a skeletally immature patient with neuromuscular compromise., Conclusions: Fixation type, early surgery, and spasticity management contributed significantly to the presenting condition. Mechanical factors and timing of surgery played a decisive role in this particular presentation., Level of Evidence: Level IV--Case report and review of the literature.

Study Design: A review of clinical publications, current knowledge, and recent developments regarding the etiology of ischiovertebral dysplasia was combined with a clinical review of the condition., Objective: To acquaint orthopedic spine surgeons with identification patterns of ischiovertebral dysplasia in order to provide them with guidelines about spine management and which complications to expect., Summary of Background Data: Ischiovertebral dysplasia is a rare skeletal dysplasia that may appear in a sporadic fashion or be inherited with an autosomal dominant inheritance pattern. It is defined by the association of an ischiopubic ramus hypoplasia and a vertebral dysplasia. It leads to a specific spine deformity whose management and complications should be clarified., Methods: Thirty consecutive patients from 0 to 31 years of age with ischiovertebral dysplasia were included from 5 centers specialized in congenital spinal deformities. Frontal and sagittal Cobb angles before treatment, natural history of the curves, therapeutic options, and their complications were systematically analyzed., Results: All the patients had a vertebral dysplasia and 28 of them developed a spinal deformity. This deformity was an extremely severe thoracic kyphoscoliosis in 25 cases. The other deformities were a thoracolumbar scoliosis in 1 case and a thoracolumbar kyphosis in 2 cases. The management of the thoracic kyphoscoliosis was always challenging and complications included death by respiratory failure (3 cases) and neurological impairment (9 cases)., Conclusion: Recognizing the occurrence of ischioverterbral dysplasia is very important to allow for dedicated treatment. The authors advocate preoperative distraction and circumferential fusion to prevent progression of the curve and to avoid the potentially fatal sequelae associated with this disorder., Level of Evidence: 4.

Study Design: A numerical study was conducted to identify the intervertebral stiffness of scoliotic spines from spinal flexibility tests., Objective: To study the intervertebral 3-dimensional (3D) stiffness distribution along scoliotic spine., Summary of Background Data: Few methods have been reported in literature to quantify the in vivo 3D intervertebral stiffness of the scoliotic spine. Based on the simulation of flexibility tests, these methods were operator-dependent and could yield to clinically irrelevant stiffnesses., Methods: This study included 30 patients surgically treated for severe idiopathic scoliosis. A previously validated trunk model, with patient-specific geometry, was used to simulate bending tests according to the in vivo displacements of T1 and L5 measured from bending test radiographs. Differences between in vivo and virtual spinal behaviors during bending tests (left and right) were computed in terms of vertebral rotations and translation. An automated method, driven by a priori knowledge, identified intervertebral stiffnesses in order to reproduce the in vivo spinal behavior., Results: Because of the identification of intervertebral stiffnesses, differences between in vivo and virtual spinal displacements were drastically reduced (95% of the differences less than +/-3 mm for vertebral translation). Intervertebral stiffness distribution after identification was analyzed. On convex side test, the intervertebral stiffness of the compensatory curves increased in most cases, whereas the major curve became more flexible. Stiffness singularities were found in junctional zones: these specific levels were predominantly flexible, both in torsion and in lateral bending., Conclusion: The identification of in vivo intervertebral stiffness may improve our understanding of scoliotic spine and the relevance of patient-specific methods for surgical planning.

Background: There is no consensus on the ideal treatment for malignant tumors of the distal tibia. Many favor amputation., Methods: Thirteen children, at an average age of 12 years (8 to 16 y) sustained conservative surgical treatment for a tumor of the distal tibia. All patients had "en bloc" resection of the tumor with ankle arthrodesis achieved by nail or plate accompanied by autograft., Results: The results were assessed retrospectively with an average follow-up of 8.8 years. Nine patients were in complete remission. Two patients had died. Two patients were lost to follow-up. Two patients had a local recurrence, which required amputation. There were 4 infections, which responded well to therapy. Four patients required additional bone grafting because of nonunion. Three patients required osteotomy for malalignment. Bone healing was achieved for the 9 patients seen at last follow-up. All were able to walk with an average functional score of 24.7/30 (23 to 26) on the Musculoskeletal Tumor Society score., Conclusions: Several reconstructive techniques are available: mega prosthesis of distal tibia and ankle, reconstruction by vascularized fibula or by autograft. All series reported significant rates of infections, cutaneous necrosis, and nonunion., Discussion: Conservative treatment with ankle arthrodesis is a possible alternative to amputation for the management of malignant tumors of the distal tibia in selected patients. Survival results and functional outcome were good despite initial complications., Level of Evidence: This is a retrospectively therapeutic study graded level 2 as level of evidence.

Study Design: A numerical study was conducted by simulating the Cotrel-Dubousset (CD) surgery., Objective: To quantify intraoperative correction during CD surgery., Summary of Background Data: Very few methods have been reported in literature to analyze the effect of intraoperative surgical gestures, and none considers the three-dimensional correction of the entire spine during the main surgical gestures. Intraoperative frontal radiographs limit analysis to two-dimensional correction, and movement tracking devices focus the kinematics study of specific vertebrae in the instrumented area only., Methods: This study included 20 patients, mean age 15 years, with severe idiopathic scoliosis treated by CD surgery. A patient-specific finite-element model (T1-L5 and pelvis), based on preoperative stereo-radiography and flexibility test radiographs, was constructed for each patient. An automated algorithm simulated all the main steps of the CD surgery. For each step, vertebral kinematics was exported to compute the evolution of various clinical parameters. Coherence of the simulations was evaluated by comparing the virtual postoperative spinal configuration with postoperative in vivo data., Results: The CD surgery affected the vertebral levels inside but also outside the fused spinal area, in a three-dimensional complex kinematics. Every intraoperative maneuver contributes to scoliosis correction. The second rod insertion, focused on the apical vertebra, leading to a global modification of all the curves., Conclusions: The automated patient-specific simulation of CD surgery may improve our understanding of surgical biomechanics. Therefore, it could increase the relevance of preoperative surgery planning.

Study Design: Posture and motion analysis after a Cotrel-Dubousset instrumentation., Objectives: To investigate the compensation role of pelvis., Summary of Background Data: Few existing studies found no compensation at the lower unfused level but did not investigate the pelvis., Methods: Thirty patients were analyzed before surgery then at short-, medium-, and long-term postoperative follow-up. Calibrated x-rays with three-dimensional reconstruction yielded quantification of pelvic parameters. Noninvasive optoelectronic system allowed analyzing subjects first in standing position, then during flexion-extension, lateral bending, and axial rotation. Skin markers were used to quantify three-dimensional orientation of the shoulders, trunk and pelvis, and their range of motion (ROM)., Results: Ten patients among 21 had after surgery more than 5 degrees change of pelvic incidence. In flexion, global ROM decreased from preoperative to postoperative phase (P < 0.05). Global ROM variation was not correlated to that of lower unfused segment, while it was highly correlated to pelvic ROM variation (r = 0.78 at medium follow-up)., Conclusion: This study underlines the central role of pelvis in balance and motion of the patients before and after surgery.

Study Design: This study was designed to investigate the pathologic mechanisms of idiopathic scoliosis using experimentally induced scoliosis in chickens., Objective: To understand the process of producing a scoliotic deformity in pinealectomized chickens., Summary of Background Data: Pinealectomy in chickens consistently produces scoliosis with anatomic characteristics similar to those of human idiopathic scoliosis. Pinealectomized chickens are an important animal model for the study of idiopathic scoliosis., Methods: In this study, 40 chickens were divided into two groups; 20 chickens treated with pinealectomy and 20 with a sham operation as control subjects on the second after hatching. The chickens in both groups then were killed at intervals ranging from 1 to 20 weeks after surgery. Their spines were examined visually and radiologically for the presence of a scoliotic curve and vertebral deformities., Results: Rotational lordoscoliosis developed in pinealectomized chickens. The chickens with severe scoliosis were characterized by apically wedge-shaped vertebrae. In contrast, no scoliosis with any vertebral deformity developed in any of the chickens that received a sham operation., Conclusions: Because there normally is evidence of lordosis in the thoracic spine of chickens, the rotational instability of the spine induced by pinealectomy may produce a scoliotic deformity as a secondary phenomenon. Pinealectomy in chickens consistently produces scoliosis with anatomic characteristics similar to those of human idiopathic scoliosis. The authors believe that disturbance of the equilibrium and the posture mechanism associated with a defect in melatonin synthesis after pinealectomy may promote the development of rotational lordoscoliosis.

Study Design: This was a retrospective review of a consecutive series of patients with neuromuscular spinal deformity who underwent posterior fusion and pelvic fixation using a long construct and an iliosacral screw., Objectives: To evaluate the risks and benefits of iliosacral screw fixation., Summary of Background Data: Neuromuscular scoliosis with pelvic obliquity poses one of the most challenging instrumentation problems, mainly because of the poor bone quality frequently found within the sacrum. Complications include failure of instrumentation, loss of sacral fixation, loss of lumbar lordosis, and a high rate of nonunion., Methods: One hundred fifty-four patients with neuromuscular scoliosis and pelvic obliquity underwent posterior arthrodesis with pelvic fixation using an iliosacral screw. Anteroposterior scoliosis Cobb angle, frontal pelvic obliquity, and sacral inclination angle were measured before surgery, immediately after surgery, and at the 5-year and 3-month follow-up examination. Influence of etiology, severity of deformity, and associated anterior release at the scoliotic curve above also were assessed., Results: Correction of scoliosis Cobb angle ranged from 53% to 70%, and loss of correction ranged from 3% to 14% at the last follow-up examination. Correction of pelvic obliquity ranged from 60% to 84%, and loss of correction was mild. Sacral inclination angle approached normal values in all patients, except for those with myelomeningocele who had preoperative pelvic retroversion. Loss of correction ranged from 0.3 degree to 5.4 degrees at the last follow-up examination. Complications and loss of correction mostly were encountered in patients with myelomeningocele and spinal muscular atrophy., Conclusions: Iliosacral screw fixation in neuromuscular scoliosis is technically standardized and easy and offers mechanically efficient and stable fixation.

Study Design: The effect of intraperitoneal injection of 5-hydroxytryptophan (5-HTP) versus control in pinealectomized chickens., Objective: To find if the serotonin may have some role in the cause of treatment of idiopathic scoliosis., Summary of Background Data: One of the causes of idiopathic scoliosis is thought to be the disruption of postural reflex. Serotonin has been proposed to have a crucial role in maintaining normal postural muscle tone or postural equilibrium., Method: Forty pinealectomized chickens served as controls, and an additional 40 pinealectomized chickens received daily intraperitoneal injections of 5-hydroxy-tryptophan, a precursor of serotonin, which can pass through the blood-brain barrier. Spine radiographs were examined to measure the scoliotic deformity., Results: Scoliosis developed in all 40 pinealectomized chickens (control), whereas only 28 chickens in the 5-hydroxytryptophan-treated group (6 in severe, 22 in mild) had scoliosis developed. The remaining 12 chickens grew up with normal spines. Most chickens with mild scoliosis did not have curve progression but continued to have wedged vertebrae., Conclusion: Serotonin deficit secondary to a defect of melatonin may have disturbed postural muscle tone or postural equilibrium resulting in scoliosis in pinealectomized chicken. Prevention from the development of scoliosis or its progression in chickens treated with 5-hydroxytryptophan suggests that serotonin may have potential therapeutic value.

Study Design: A retrospective review of a series of 12 children who underwent suboccipital foraminotomy and duroplasty for Chiari I malformation., Objective: To assess the effects of this surgery on associated syringomyelia and scoliosis., Summary of Background Data: Suboccipital foraminotomy for the treatment of syringomyelia associated with Chiari I malformation was greatly stimulated by Gardner's hydrodynamic theory, and its results proved to be encouraging. However, several authors reported improvement or stabilization of associated scoliosis after this surgery., Methods: A retrospective review was conducted on 12 patients who underwent suboccipital foraminotomy for Chiari I malformation associated with syringomyelia. Neurologic Impairment, extent of syringomyelia, and severity of associated spinal deformity were assessed preoperatively and at a 4.5-year average follow-up (range, 2.1-12 years). Anomaly of superficial abdominal reflexes was found in all cases, and para or tetraparesis in three cases. Syringomyelia was of variable localization and extent. Scoliosis was present in 7 cases (greater than 40 degrees in 5 cases)., Results: Diminution or complete disappearance of syringomyelia was observed in 11 cases, 3 months to 1 year after surgery. Superficial abdominal reflexes anomaly improved in four cases. Minimal neurologic deficit persisted in one case. Scoliosis improved in one case, remained unchanged in one case, and progressed in the five cases with preoperative severe deformity, requiring instrumentation and fusion., Conclusions: Improvement of syringomyelia and neurologic deficit, observed with suboccipital foraminotomy, supports the theory that abnormal hydrodynamics of the cerebral spinal fluid is most likely to cause these deficits.

Study Design: This study analyzes the effects of a new anterior spinal instrumentation system and the results of use in 50 patients with scoliosis., Objectives: Anterior spine systems are reviewed. The principles of a new anterior spinal instrumentation system allowing for postoperative care without external support are discussed., Summary of Background Data: Numerous different implants have been presented in the literature for anterior spinal surgery. Nevertheless a primary stable anterior instrumentation was not available for multisegmental procedures until now, and the restoration of lordosis in the lumbar spine was very difficult with the common devices. The development of more stable devices that also allow a restoration of lordosis in combination with derotation and compression is discussed., Methods: Fifty patients with scoliosis of different etiologies (neuromuscular: n = 33; idiopathic: n = 16; congenital: n = 1) underwent anterior spinal surgery at the thoracic, thoracolumbar, and lumbar spine. During follow-up, no revision operation was necessary after the monosegmental and multisegmental application of this method, and there were no vessel complications. The results were controlled with a mean follow-up of 26.6 (range 12-41) months., Results: Clinical and radiologic follow-up and complications are reported. Statistical data obtained show a different average blood loss and operation time depending on the different etiology of the scoliotic deformity. The mean corrections for the scolioses by etiology are as follows: myelomeningocele (MMC) (mean preoperative angle 89 degrees, mean correction 54%); neuromuscular (81 degrees, 46%); and idiopathic (55 degrees, 69%). The mean lordosis of the lumbar spine was 29.2 degrees (measured between T12-S1) and could be corrected to 45.2 degrees depending on the etiology of the curvature, whereas the angle of the thoracic kyphosis did not show an essential change. The segmental measurement in idiopathic scoliosis did not show a kyphosization in the lumbar spine. Derotation of the apical vertebra in 15 patients in relation to the sagittal plane was 37%., Conclusions: The study shows the effect of a new anterior device allowing the application of three-dimensional correction forces to the spine. Particularly in scoliosis derotation, compression and restoration of lordosis are possible. Primary stability is obtained by anchoring the implants with a new wedge-locking technique, which makes postoperative external support unnecessary.

Study Design: The serum melatonin levels during 24-hour periods were compared between patients with idiopathic and age-matched normal control subjects., Objective: To find if the melatonin deficiency may have some role for progression or etiology of idiopathic scoliosis in humans., Summary of Background Data: Experimentally induced scoliosis in chicken by pinealectomy can be attributed to the defect in melatonin metabolism., Method: Blood samples were correlated every 3 hours during 24-hour periods, and serum melatonin levels were measured and statistically analyzed., Results: The level of melatonin, integrated concentration through 24 hours and night time (0:00 am-6:00 am), in the patients who had progressive curve (more than 10 degrees of progression in the previous 12 months) was significantly lower than the level in the patients who had a stable curve (less than 10 degrees of progression in the previous 12 months) or in the control subjects (P < 0.05)., Conclusion: The study suggests that normal melatonin synthesis or metabolism may have crucial role in regulating normal spine growth. The level of melatonin appears to be a useful predictor for progression of spine curvature in idiopathic scoliosis.

Experimentally induced scoliosis was investigated in pinealectomized chickens using pathologic and neurophysiologic means. A total of 90 chickens were tested; 30 served as a normal control, 30 received an autografted pineal body in the intramuscular tissue of the trunk, and 30 underwent pinealectomy without autograft. Scoliosis developed in all pinealectomized chickens within 2 weeks, showing gradual progression during the next 5 or 6 weeks. At 3 months, the three-dimensional spinal deformity consisted of lateral curvature and vertebral body rotation, resulting in a prominent lordoscoliosis at the thoracic level. In contrast, scoliosis developed in only 10% of the autografted chickens. Histologic examination revealed no pathologic change in the brain in either the pinealectomized scoliosis group or in the autografted nonscoliosis group. Cortical potentials in the scoliosis group were delayed, thus suggesting conduction disturbance rostral to the brain stem. Although the relationship between the cause and effect is uncertain, these findings implicate neurotransmitters or neurohormonal systems in the pineal body as a major contributing factor in this type of experimental scoliosis.