Bone substitutes in adolescent idiopathic scoliosis surgery using sublaminar bands: is it useful? A case-control study.

INTRODUCTION: In order to avoid pseudarthrosis in adolescent idiopathic (AIS) patients, it is recommended to bring additional bone graft or substitute. Modern rigid instrumentations have been shown to provide less pseudarthroses even without bone substitutes. The aim of our study was to determine the impact of using bones substitutes on fusion rates in adolescent idiopathic scoliosis patients undergoing PSF with sublaminar bands. METHOD: AIS patients scheduled to undergo PSF with sublaminar bands were prospectively enrolled into this study and not given any bone substitutes (no-substitute group). Data were collected and analyzed in patients with at least two years of follow-up. Pseudarthrosis was diagnosed if at least one of the following was present: persistent back pain, hardware failure, loss of correction greater than 10°. The results were compared to a control group who received bone substitutes for the same surgical procedure. RESULTS: Eighty-eight patients were included. For the whole cohort, the mean age was 14.8 years old and the mean follow-up was 30.9 months. For the 'no-substitute' group (n = 44), the mean Cobb angle was 56° pre-operatively, 20.1° post-operatively, and 22° at final follow-up. The fusion rate was not statistically different between the two groups (97.7% vs 95.5%, p = 0.56). At last follow-up, one pseudarthrosis occurred in the 'no substitute' group and two in the control group. DISCUSSION: This is the first study to determine the impact of bone substitutes in AIS fusion using sublaminar bands. In our study, the use of local autologous bone graft alone resulted in a fusion rate of 97.7% despite the use of more flexible instrumentation. The high rate of fusion in AIS patients is more probably due to the healing potential of these young patients rather than to the type of instrumentation. CONCLUSION: The use of additional bone graft or bone substitutes may not be mandatory when managing AIS. LEVEL OF EVIDENCE: 4.

The lateral wedge augmentation trochleoplasty in a pediatric population: a 5-year follow-up study.

Patellofemoral instability in children requires surgery when recurrent dislocation occurs. The aim of this study is to report the 5-year clinical and radiographic outcomes following lateral wedge augmentation trochleoplasty of the femoral trochlea. This is a review of 23 (mean age: 12.5 years) patients who underwent surgery for recurrent patellar dislocations related to a flat trochlea. In every case, a lateral wedge augmentation trochleoplasty was performed with preservation of the growth plate. This surgery was consistently associated with a soft tissue procedure. All patients were reviewed for a clinical and radiographic evaluation [computed tomography (CT)-scan]. No case of recurrent patellar dislocation was reported and all patients were satisfied with the procedure; three patients reported anterior knee pain after physical activities. CT scan analysis revealed improvement of the trochlear shape measurements in all cases, but osteoarthritis lesions (narrowing of the lateral patellofemoral compartment) were visible on four CT scans. This trochleoplasty technique augmented by a soft tissue procedure on the extensor apparatus led to acceptable clinical mid-term results in terms of stability for patients with a flat trochlea (grade B according to Dejour classification). However, at the 5-year follow-up, four patients showed signs of osteoarthritis on CT scan evaluation. This warrants serious concern in this young population, and alternative methods should be considered whenever possible.

Intraoperative spinal cord monitoring in children under 4 years old.

PURPOSE: The purpose was to study intraoperative spinal cord monitoring (IOM) particularities and performances in children under 4 years old with congenital spinal deformities. IOM is characterized by specific difficulties due to the immaturity of sensory-motor pathways in such young patients. To the best of our knowledge, this study is the largest dedicated to IOM in this challenging population. METHODS: This study was retrospective and monocentric. 78 IOM in children under 4 years old were analyzed. Somatosensory evoked potentials (SSEP), neurogenic mixed evoked potentials (NMEP) and D waves were performed. Patients were classified into one of four categories with respect to IOM data and clinical outcome: true positive, false positive, true negative and false negative. Sensitivity and specificity were then calculated accordingly. RESULTS: There were 6 true positive, 3 false positive, 67 true negative and 1 false negative outcomes. One patient was characterized by unreliable baseline IOM data. IOM sensitivity was 86 %. IOM specificity was 96 %. The false negative case was monitored using SSEP alone. IOM was difficult in 10/77 cases, being unilateral because of a planned fibular graft harvest. NMEP were characterized by higher signal-to-noise ratio than SSEP. CONCLUSIONS: Immaturity of sensory-motor pathways predominates in the central rather than the peripheral nervous system in young children. MEP and D waves could thus be difficult to obtain. Although non-specific to motor pathways, it could be useful to "by-pass" the brain, using NMEP. In regard to maturational particularities, IOM in children under 4 years old should be performed by experienced neurophysiologists, avoiding in these cases surgeon-guided devices.

Experience in Perioperative Management of Patients Undergoing Posterior Spine Fusion for Neuromuscular Scoliosis.

The objective of this investigation was to determine the outcome of spine fusion for neuromuscular (NM) scoliosis, using Unit Rod technique, with emphasis on complications related to preoperative general health. Between 1997 and 2007, 96 consecutive patients with neuromuscular scoliosis operated on with Unit Rod instrumentation were retrospectively reviewed. The inclusion criteria were diagnosis of NM scoliosis due to cerebral palsy (CP) and muscular dystrophy (DMD). Patient's preoperative general health, weight, and nutrition were collected. Different radiographic and clinical parameters were evaluated. There were 66 CP patients (59 nonwalking) and 30 DMD patients (24 nonwalking). Mean age at surgery was 16.5 years and 13.9 years, respectively. All radiographic measurements improved significantly. Wound infection rate was 16.7% (11% of reoperation rate in CP; 10% in DMD; 3 hardware removal cases). No pelvic fracture due to rod irritation was observed. Unit Rod technique provides good radiographic and clinical outcomes even if this surgery is associated with a high complication rate. It is a quick, simple, and reliable technique. Perioperative management strategy should decrease postoperative complications and increases outcome. A standardized preoperative patient evaluation and preparation including respiratory capacity and nutritional, digestive, and musculoskeletal status are mandatory prior to surgery.

Postural spinal balance defined by net intersegmental moments: Results of a biomechanical approach and experimental errors measurement.

AIM: To describe initial results and experimental error measurement of a protocol analyzing Human posture through sagittal intersegmental moments. METHODS: Postural analysis has been recently improved by development of three-dimensional radiographic imaging systems. However, in various situations such as global sagittal anterior malalignment interpretation of radiographs may not represent the real alignment of the subject. The aim of this study was to present initial results of a 3D biomechanical protocol. This protocol is obtained in a free standing position and characterizes postural balance by measurement of sagittal intersegmental net moments. After elaboration of a specific marker-set, 4 successive recordings were done on two volunteers by three different operators during three sessions in order to evaluate the experimental error measurement. A supplementary acquisition in a "radiographic" posture was also obtained. Once the data acquired, joint center, length, anatomical frame and the center of mass of each body segment was calculated and a mass affected. Sagittal net intersegmental moments were computed in an ascending manner from ground reaction forces at the ankles, knees, hips and the lumbo-sacral and thoraco-lumbar spinal junctions. Cervico-thoracic net intersegmental moment was calculated in a descending manner. RESULTS: Based on average recordings, clinical interpretation of net intersegmental moments (in N.m) showed a dorsal flexion on the ankles (8.6 N.m), a flexion on the knees (7.5 N.m) and an extension on the hips (8.5 N.m). On the spinal junctions, it was flexion moments: 0.34 N.m on the cervico-thoracic; 6.7 N.m on the thoraco-lumbar and 0.65 N.m on the lumbo-sacral. Evaluation of experimental error measurement showed a small inter-trial error (intrinsic variability), with higher inter-session and inter-therapist errors but without important variation between them. For one volunteer the "radiographic" posture was associated to significant changes compared to the free standing position. CONCLUSION: These initial results confirm the technical feasibility of the protocol. The low intrinsic error and the small differences between inter-session and inter-therapist errors seem to traduce postural variability over time, more than a failure of the protocol. Characterization of sagittal intersegmental net moments can have clinical applications such as evaluation of an unfused segment after a spinal arthrodesis.

Pelvic incidence: a predictive factor for three-dimensional acetabular orientation-a preliminary study.

Acetabular cup orientation (inclination and anteversion) is a fundamental topic in orthopaedics and depends on pelvis tilt (positional parameter) emphasising the notion of a safe range of pelvis tilt. The hypothesis was that pelvic incidence (morphologic parameter) could yield a more accurate and reliable assessment than pelvis tilt. The aim was to find out a predictive equation of acetabular 3D orientation parameters which were determined by pelvic incidence to include in the model. The second aim was to consider the asymmetry between the right and left acetabulae. Twelve pelvic anatomic specimens were measured with an electromagnetic Fastrak system (Polhemus Society) providing 3D position of anatomical landmarks to allow measurement of acetabular and pelvic parameters. Acetabulum and pelvis data were correlated by a Spearman matrix. A robust linear regression analysis provided prediction of acetabulum axes. The orientation of each acetabulum could be predicted by the incidence. The incidence is correlated with the morphology of acetabula. The asymmetry of the acetabular roof was correlated with pelvic incidence. This study allowed analysis of relationships of acetabular orientation and pelvic incidence. Pelvic incidence (morphologic parameter) could determine the safe range of pelvis tilt (positional parameter) for an individual and not a group.

Circumferential fusion using a custom-made screw in the management of high-grade spondylolisthesis.

PURPOSE: Management of high-grade spondylolisthesis is challenging and to date no therapeutic consensus is available. Various surgical procedures have been described using unique or double approach. The aim of the study is to describe an original technique using a posterior-only approach to achieve a circumferential lumbosacral fusion with a custom-made screw. METHODS: In our experience, eight patients (mean age 15 years old) were treated for grade III or IV slipping without instrumental reduction. Surgical technique included a laminectomy from L5 to S2, then after mobilization of neural elements a guide wire was inserted from the posterior side of S2 to the antero-superior corner of L5. A specific drill was used and the 10-mm screw was then inserted under fluoroscopic guidance. Further steps included a discectomy, lumbosacral interbody graft and posterolateral graft to obtain a circumferential fusion. Clinical and radiological evaluations were obtained. RESULTS: On the whole series, solid fusion was achieved after 6 months on average. Sagittal realignment was observed with a regression of pelvic retroversion and hip flessum, a lumbarization of the lumbar lordosis and an improvement of the thoracic kyphosis. For one patient, a postoperative S1 deficit was observed. CONCLUSION: This technique provides satisfactory results in the management of high-grade spondylolisthesis. This concept is based on a double spine instability considering viscoelastic properties of the disc and postoperative sagittal reciprocal changes as prerequisite. This posterior-only approach represents a valuable alternative to other procedures.

Small bone islands: unusual clinical symptomatology.

Bone islands are usually considered benign, stable, nonprogressive lesions, radiographically characterized by an ovoid, round, or oblong homogeneously dense and sclerotic focus in the spongiosa, with a preference for the long bones and the pelvis. Benign solitary bone islands are usually believed to be asymptomatic, with no necessity for treatment. Symptomatic bone islands reported in the literature are characterized by a diameter greater than 2 cm, belonging to the category of giant bone islands. The authors report a rare case starting from a painful symptomatology and involving dense sclerotic bone lesions of less than 2 cm, thus falling into the category of small bone islands. The patient underwent a surgical resection to achieve complete recovery. Normally, small bone islands do not explain the pain in patients who present with symptomatology when they are detected during radiographic studies. Based on this case, the authors believe that even small bone islands can be the cause of symptomatology and justify a surgical procedure if all medical investigations suggest no other possible causes of the pain.

Complications in pediatric spine surgery using the vertical expandable prosthetic titanium rib: the French experience.

STUDY DESIGN: Multicenter retrospective study of 54 children. OBJECTIVE: To describe the complication rate of the French vertical expandable prosthetic titanium rib (VEPTR) series involving patients treated between August 2005 and January 2012. SUMMARY OF BACKGROUND DATA: Congenital chest wall and spine deformities in children are complex entities. Most of the affected patients have severe scoliosis often associated with a thoracic deformity. Orthopedic treatment is generally ineffective, and surgical treatment is very challenging. These patients are good candidates for VEPTR expansion thoracoplasty. The aim of this study was to evaluate the potential complications of VEPTR surgery. METHODS: Of the 58 case files, 54 were available for analysis. The series involved 33 girls and 21 boys with a mean age of 7 years (range, 20 mo-14 yr and 2 mo) at primary VEPTR surgery. During the follow-up period, several complications occurred. RESULTS: Mean follow-up was 22.5 months (range, 6-64 mo). In total, 184 procedures were performed, including 56 VEPTR implantations, 98 expansions, and 30 nonscheduled procedures for different types of complications: mechanical complications (i.e., fracture, device migration), device-related and infectious complications, neurological disorders, spine statics disturbances. Altogether, there were 74 complications in 54 patients: a complication rate of 137% per patient and 40% per surgery. Comparison of the complications in this series with those reported in the literature led the authors to suggest solutions that should help decrease their incidence. CONCLUSION: The complication rate is consistent with that reported in the literature. Correct determination of the levels to be instrumented, preoperative improvement of nutritional status, and better evaluation of the preoperative and postoperative respiratory function are important factors in minimizing the potential complications of a technique that is used in weak patients with complex deformities.

Siblings with vascular involvement associated with hereditary multiples exostosis.

Multiple hereditary exostoses are frequently observed in children, but vascular complications from exostoses in siblings are rare. We report the case of a 10-year-old boy, admitted for dyspnea and chest pain related to a hemothorax due to a right eighth rib exostosis. He was successfully treated by costal resection and chest tube drainage. In retracing his family history, another vascular involvement was discovered. His sister had presented a few years earlier with a spontaneous rupture of brachial artery with radial nerve palsy. To date, only a few cases of spontaneaous hemothorax related to a thoracic exostosis have been described, and to our knowledge, a family association of vascular lesions has not been reported yet. Patients with multiple hereditary exostoses require clinical and radiographic follow-ups during growing years. The main problem is determining the best way to identify dangerous exostoses that may cause vascular lesions. In association with standard surveillance of patients with multiple hereditary exostoses, we suggest performing specific examinations in cases of known thoracic lesions and for patients with a family history of vascular impingement.

Do adolescent idiopathic scoliosis (AIS) neglect proprioceptive information in sensory integration of postural control?

INTRODUCTION: It has been reported that AIS rely much more on ankle proprioception to control the amplitude of the balance control commands as compared to age-matched healthy adolescents. Our hypothesis was that AIS do not neglect proprioceptive information to control posture probably because of their vestibular deficits. We investigated the proprioceptive contribution to postural control in AIS which expresses spinal deformity during a crucial transitional period of ontogenesis. METHODS: 10 adolescents with idiopathic scoliosis (AIS) with moderate spinal deformity (10° < Cobb Angle >35°) and 10 control adolescents (CA) had to maintain vertical stance while very slow oscillations in the frontal plane (below the detection threshold of the semicircular canal system) were applied to the support with the eyes open and closed. Postural orientation and segmental stabilisation were analysed at head, shoulder, trunk and pelvis levels. RESULTS: Scoliosis did not affect vertical orientation control and segmental stabilization strategies. Vision improves postural control in both CA and AIS, which seem more dependent on visual cues than adults. CONCLUSIONS: AIS as CA were unable to control efficiently their postural orientation on the basis of the proprioceptive cues, the only sensory information available in the EC situation, whereas in the same condition healthy young adults present no difficulty to achieve the postural control. This suggests that AIS as CA transitory neglect proprioceptive information to control their posture. These results and previous studies suggest the existence of different afferent pathways for proprioceptive information subserving different parts in sensory integration of postural control. We conclude that the static proprioceptive system is not affected by the idiopathic scoliosis, while the dynamic proprioceptive system would be mainly affected.

Dynamic equinus with hindfoot valgus in children with hemiplegia.

In children with hemiplegia, it is important to distinguish between equinus with hindfoot varus (equinovarus) or valgus (equinovalgus). Premature onset of medial gastrocnemius (GM) EMG in individuals with equinus is well documented. Premature onset of Peroneus longus (PL) EMG has been described in neurologically impaired adults with equinovalgus, but not in children. Our aim was to record the onset of PL and GM activity on the hemiplegic side of children with equinovalgus deformity. Fifteen children GMFCS 1 (3.8 yrs ± 2) with hemiplegia had a goniometric assessment of passive ankle range of motion and assessment of ankle function from video and surface EMG recording during gait. The clinical and video observations were used to determine the equinovalgus, as defined by Wren, at initial contact (IC). The premature onset of muscle activity was normalised as a swing (SW) percentage prior to IC of the following stance (ST). A paired T-test compared the onset of muscle activity between PL and GM. The ankle passive dorsiflexion was 13° ± 12° (hemiplegic side) versus 18° ± 10° (non-involved side) (p<0.05). For the non-involved limb, the onset of GM activity was at 14% of the gait cycle (midstance), the onset of PL activity was at 19% (p<0.05). For the hemiplegic limb with equinovalgus, there was a premature onset activity of PL (-24%) and GM(-8%) (p<0.001). On the non involved side, the onset of PL activity occurred, as in adults, after the onset of GM activity, during ST. On the hemiplegic side, there was no triceps surae contracture and the onset of PL activity occurred prior to the onset of GM activity, during terminal SW. This study confirmed the overactivity of PL in hemiplegic children with equinovalgus.

Beyond the classic correction system: a numerical nonrigid approach to the scoliosis brace.

BACKGROUND CONTEXT: Adolescent idiopathic scoliosis (AIS) causes a spine and rib cage three-dimensional (3D) deformity previously treated by bracing. Whatever the manufacturing process, this rigid system acts biomechanically on the patient through the "three-point bending" mechanical principle. It applies corrective forces to a limited area and acts especially in the frontal plane. It seemed to us that a nonrigid system, called "Cbrace," with 3D action allowing distribution of forces could increase compliance and provide better long-term correction prospects. PURPOSE: The aim of this study was to design a nonrigid brace by numerically testing in a finite-element model developed here. STUDY DESIGN: A finite-element model has been developed to simulate brace effect on AIS right thoracic deformation of a 10-year-old patient. METHODS: A two-step method was needed; first, the reliability of our model is evaluated, and then, the ability to use distributed forces to correct scoliosis deformation is tested. To obtain a 3D correction, several treatments are experimented, leading to a comparison test between the best combination to the "three-point bending" principle. RESULTS: The numerical model developed here shows good qualitative answers for the treatment of brace forces. The first results demonstrate numerically that distributed forces may be of interest in brace treatment design. Overall force of 40 N above cartilage of the last nonfloating ribs associated to two posterior asymmetrical areas appears to be the best way to correct scoliosis deformation with nonrigid action. CONCLUSION: The results show numerical efficacy of distributed forces to correct spinal deformities and raises the prospect that a new numerical brace, called "Cbrace," could be a starting point in the search for a nonrigid system.

Progressive anterior vertebral bars: a study of 16 cases.

STUDY DESIGN: In a retrospective study, we report on 16 patients with congenital kyphosis due to progressively ossifying anterior unsegmented bars. OBJECTIVE: To specify the therapeutic strategy in such malformation. SUMMARY OF BACKGROUND DATA: Congenital kyphosis due to progressively ossifying anterior unsegmented bars is a particular and uncommon entity of congenital kyphosis. Progressive anterior vertebral bars result in slowly progressive kyphosis, which rarely lead to neurological compromise. Sagittal equilibrium of the spine is maintained by compensatory curves adjacent to the primary curve. METHODS: All patients had clinical assessment and successive measurements of segmental angle made on a standing lateral radiograph of the spine. Magnetic resonance imaging was obtained in four patients. Six patients were just observed. A brace was used in three. And seven were treated surgically. RESULTS: The compensatory capacity of the spine is reduced in lumbar area where there are few discs spaces below the bar. Presentation therefore tends to be at an earlier age and pain is more common.Magnetic resonance imaging enables definition of the structures immediately posterior to the bar and provides information regarding the integrity of the intervertebral disc. CONCLUSION: There is usually no need for surgery in thoracic and thoracolumbar localization. In lumbar localization, if the diagnosis is done early in childhood and if magnetic resonance imaging shows beyond the anterior ossification a normal T2-weighted magnetic resonance imaging disc space signal, desepiphysiodesis bar resection and cement interposition is mandatory. If the disc magnetic resonance imaging signal is abnormal or if the disc space is totally ossified, we propose a surgical correction of the kyphosis. For such cases a posterior wedge osteotomy seems to be the more suitable procedure.

Anterior dislocation of the sacroiliac joint in children: a new technique for pelvic fixation.

Pelvic injuries in children and especially sacroiliac anterior dislocation are uncommon lesions. In this study, we present an original technique for the fixation of such lesions by a custom-made frame through a single posterior approach. The case of a 12-year-old girl is reported here and advantages of this technique are described. At final follow-up, healing of the lesion was achieved with favourable clinical and radiological outcomes.

Intraoperative monitoring in pediatric orthopedic spinal surgery: three hundred consecutive monitoring cases of which 10% of patients were younger than 4 years of age.

STUDY DESIGN: Analysis of a prospective series of 300 consecutive cases undergoing intraoperative monitoring in pediatric orthopedic spinal surgery, of which 10% were children younger than 4 years. OBJECTIVE: Determine feasibility and performance of intraoperative monitoring in children younger than 4 years. Analyze distinct physiopathologic mechanisms of relevant alerts. SUMMARY OF BACKGROUND DATA: There are few studies in the literature concerning the intraoperative monitoring of children younger than 4 years. During childhood, the development of sensori-motor pathways is dominated by two coexisting phenomena, which have opposite effects: maturation decreasing latencies and height increasing them. METHODS: We used intraoperative somatosensory-evoked potentials and neurogenic mixed evoked potentials with a flexible bipolar epidural electrode. Uniform total intravenous anesthesia was used. RESULTS: Values of sensitivity and specificity of the monitoring showed slight differences between patients younger than 4 years versus older patients. There was no false-negative outcome. Various tendencies were highlighted. There were more true positive alerts for secondary etiologies than for idiopathic ones, for revision spinal surgeries than for index ones, and for boys than for girls. There were no more true positive alerts for children younger than 4 years than for older patients whereas the proportion of hemivertebrae was obviously greater for the younger group. Relevant monitoring alerts were more frequent in case of kyphoscoliosis. This is highlighted in case reports. CONCLUSION: In some cases of kyphoscoliosis, during a posterior-based vertebral column resection, monitoring changes were corrected by positioning a rod that allowed correction of the position of the spine in the sagittal plane. Intraoperative spinal cord monitoring can be performed in children younger than 4 years and allows real-time assessment of spinal functional integrity.

Use of the Universal Clamp in adolescent idiopathic scoliosis for deformity correction and as an adjunct to fusion: 2-year follow-up.

PURPOSE: Among posterior surgical techniques for treating adolescent idiopathic scoliosis (AIS), hybrid constructs with pedicle-screw fixation in the lumbar spine and other anchors in the thoracic spine have been reported to provide to be of more physiological value in postoperative thoracic kyphosis than all-screw constructs. The Universial Clamp (UC) equipped with a soft sublaminar band is a relatively new thoracic anchor that can be used in hybrid constructs. A dedicated reduction tool that applies traction to the sublaminar band permits gentle translation of the thoracic curve to the precontoured fusion rods, which have been previously anchored distally by pedicle screws and proximally by hooks in a claw configuration. The aim of this study was to evaluate radiographic results of AIS treatment using UC hybrid constructs. METHODS: This was a prospective case series in which 29 consecutive patients with Lenke type 1, 2 or 3 AIS operated on by two surgeons in two centers were followed for 24 months. Necessity for anterior release was an exclusion criterion. RESULTS: A total of 5.4 ± 1.4 UCs were used per patient. The major thoracic curve was reduced from 55 ± 7° to 14 ± 6° at 1 month and 17 ± 6° at 24 months (correction 70%) without complications. In the patients who had less than 20° of T5-T12 kyphosis preoperatively, thoracic kyphosis improved from 14 ± 4° to 20 ± 3° at 3 months and 24 ± 9° at 24 months. In the other patients, preoperative thoracic kyphosis (27° ± 6°) was unchanged by the operation. CONCLUSION: UC hybrid constructs appear to safely provide satisfying coronal correction while consistently improving thoracic kyphosis in patients who also have preoperative hypokyphosis. We hypothesize that diminution in thoracic kyphosis was consistently avoided due to the straightforward traction of the spine to the fusion rods into which the chosen kyphosis was contoured by the surgeon before applying the reduction tool to the sublaminar bands.

Hexapodal external fixation in the management of children tibial fractures.

Some tibial fractures in children require surgical osteosynthesis, mostly achieved by an internal fixation. Indications for external fixation in the management of tibial fractures in children are limited to specific clinical situations when conventional treatments are contraindicated. The aim of this study is to report the results of tibial fractures management by hexapodal external fixation. Eleven children were included in this study and all of them were treated by a specific hexapodal external fixator, with a 12-month mean follow-up. In the whole series, initial deformities were perfectly corrected in nine cases, two patients showed residual deformity that did not require further surgery. The mean time for external fixation was 98 days. Hexapodal external fixation seems to be a simple and effective definitive method for the correction of three-dimensional traumatic deformities requiring surgical stabilization. Long-term follow-up will be necessary to evaluate residual deformities at the end of patient's growth.

Idiopathic scoliosis and balance organisation in seated position on a seesaw.

The aim was to determine the biomechanical processes involved in postural regulation when self-imposed disturbances occur in the seated position in the antero-posterior direction. Twelve female adolescents with right thoracic scoliosis (SG) (Cobb = 30.4 degrees +/- 9.7) and 15 control adolescents (CG) were included in this study. The ground reaction forces (GRF) were studied whilst the subjects maintained their balance in the sitting position on a seesaw. Six conditions were tested: eyes open and closed; with an additional load placed on the subject's right or left shoulder; and with an additional load on the subject's right or left pelvis. The SG showed significantly higher force amplitudes and variability and fewer oscillations than the CG in all the conditions. In the SG, the time analysis showed that the duration of the GRF was significantly higher in forward and left directions. Whatever the condition tested, the intra-group differences were not significant. The scoliotic patients in seated position were characterised by larger changes of the GRF, especially with a postural control in the forward and left directions, corresponding to that on the concave side of their spinal curvature. No significant differences were found to exist between the various conditions (load and unload, eyes open and eyes closed). Clinical tests and rehabilitation methods should include assessments of seated patients' spatio-temporal adaptation to GRF.

Use of the Universal Clamp for deformity correction and as an adjunct to fusion: preliminary results in scoliosis.

PURPOSE: Evaluation of a novel instrumentation device for adolescent idiopathic scoliosis. METHODS: A new osteosynthesis implant (Universal Clamp) primarily consisting of a sublaminar band and titanium clamp was prospectively studied in 32 patients (average age, 15 years) with a major thoracic curve. RESULTS: The Universal Clamp was used without anterior release to reduce and maintain correction of the thoracic curve, which improved from 55.1° preoperatively to 14.5° at 3 months without neurological complication or loss of kyphosis. CONCLUSIONS: This implant distributes stress over a larger area of the laminar cortex than sublaminar wires, patently reducing the risk of laminar fracture for equivalent reduction forces, and permits progressive reduction at several apical levels simultaneously.