A new technic for segmental spinal osteosynthesis using the posterior approach.

The authors have designed a new method of instrumentation aimed at obtaining surgical fixation of the scoliotic curve without any postoperative external immobilisation. It is particularly strong and rigid and allows adequate reduction of the curve. This technique avoids the sublaminar space and thus prevents excessive blood loss and diminishes the danger of cord damage. The instrumentation is made of two parallel rough cylindrical rods inserted independently in the convexity and concavity of the curve. If necessary, they can be bent pre-operatively. They are attached to hooks placed on the laminae or pedicles, which are locked by bolts, thus allowing progressive straightening of the curve. They are joined by two transverse bars, one above and one below, to provide better rigidity to the device and to allow correction of rotation. The parts of the vertebrae left free by the device are denuded to allow the addition of grafts. Laboratory tests have demonstrated that this type of fixator is more rigid than the Harrington or Luque rods. Fifteen patients, either idiopathic or paralytic cases, were operated on without any neurological impairment. No loss of correction was observed since the hooks have been locked.

Free vascularised fibular graft for reconstruction of defects of the lower limb after resection of tumour.

We describe a retrospective review of 38 cases of reconstruction following resection of the metaphysiodiaphysis of the lower limb for malignant bone tumours using free vascularised fibular grafts. The mean follow-up was for 7.6 years (0.4 to 18.4). The mean Musculoskeletal Tumor Society score was 27.2 (20 to 30). The score was significantly higher when the graft was carried out in a one-stage procedure after resection of the tumour rather than in two stages. Bony union was achieved in 89% of the cases. The overall mean time to union was 1.7 years (0.2 to 10.3). Free vascularised fibular transfer is a major operation with frequent, but preventable, complications which allows salvage of the limb with satisfactory functional results.

Analysis of idiopathic scoliosis progression by using numerical simulation.

STUDY DESIGN: The mechanisms of idiopathic scoliosis progression were investigated through a patient-specific numerical model. OBJECTIVE: To explore the combined effect of gravity, the decrease of intervertebral discs' stiffness and the anterior spinal growth on scoliosis progression, by using a numerical simulation, to better understand mechanisms of scoliosis progression. SUMMARY OF BACKGROUND DATA: Eighteen adolescents (12 girls, 6 boys) with an average age of 10.5 years (range, 7-13) were divided into 2 groups: 12 mild scoliotic patients with thoracolumbar curves and 6 asymptomatic subjects. METHODS: Accurate 3-dimensional reconstructions of the spine were performed from biplanar radiographs. A patient-specific validated finite element model was used. Four configurations were simulated for each patient: the first configuration with the spine under gravity, the second one under gravity with a decrease of disc's mechanical stiffness, the third one under gravity with anterior vertebral growth, and the last one with combination of the 3 previous configurations. RESULTS: Gravity loads resulted mainly in a vertebral lateral deviation of the curve without axial rotation for all patients with mild scoliosis. Anterior vertebral growth with gravity induced both lateral deviation and axial rotation. This phenomenon was amplified when the mechanical properties of discs were decreased. None of these simulations initiated a scoliosis-like deformity for asymptomatic subjects. CONCLUSION: For preexisting spinal curvature, an anterior spinal growth combined with gravity and a decrease of disc's mechanical stiffness could lead to a progression of scoliosis. Biomechanical factors could be secondary after initial deformation.

Delayed-iatrogenic injury of the thoracic aorta by an anterior spinal instrumentation.

We present a case of a 15-year-old girl who presented to us with an unusual low back pain. About 7 years ago, this patient had corrective surgery for her idiopathic left thoracolumbar scoliosis. Recent surgery revealed a laceration of the posterior wall of the thoracic aorta by an impending screw thread. This injury was repaired by the vascular surgeons and, subsequently, the patient had full recovery without any complications.

Resection arthrodesis of the ankle for aggressive tumors of the distal tibia in children.

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.

Analysis of the mechanisms of idiopathic scoliosis progression using finite element simulation.

The mechanisms of idiopathic scoliosis progression are still not fully understood. The aim of this study is to explore, using finite element simulation, effect of the combination of gravity and anterior spinal overgrowth on scoliosis progression. 14 adolescents (10 girls, 4 boys) with an average age of 10.8 years [range 9; 13] were divided in three groups: thoraco-lumbar scoliosis (TL), lumbar scoliosis (L), asymptomatic patients (A). Accurate 3D reconstructions of the spine have been built using bi-planar X-rays. A patient specific validated finite element model has been used. Simulations have been launched with simulation of the combined effect of gravity and growth. The progression during the simulation was defined by a maximal axial rotation movement greater or equal than 4 degrees and a maximal lateral displacement greater or equal than 5 mm ("first order progression" for one criterion, "second order" for the both criteria). In the group TL, we notice an aggravation for 4 patients (Cobb angle increase at least by 4 degrees , mean at 5.9 degrees ). Only three patients of the group L show a progression with a smaller Cobb angle increase (mean 3.9 degrees ). For the group A, no progression is found for 3 and a progression is found for 1. An anterior spinal overgrowth combined with gravity and a pre-existent curve in the spine could lead to a progression of scoliosis. It seems necessary to consider differently lumbar curves from other curves. Numerical simulation with a patient specific model appears as a useful tool to investigate mechanisms of scoliosis aggravation.

[Surgical treatment of stiff massive knee endoprosthesis for bone tumors in children and adolescents]. / Traitement chirurgical de la raideur après prothèse massive du genou pour tumeur osseuse chez l'enfant et l'adolescent.

PURPOSE OF THE STUDY: Improved oncologic outcome and technical advances in limb salvage surgery have made limb salvage therapy a feasible and valuable treatment option. Nevertheless, resection of a bone tumor followed by a reconstruction knee endoprosthesis can create gait abnormalities, of which one of the most frequent is knee stiffness. The aim of this retrospective study was to assess the outcomes of revision surgery for a stiff knee following reconstruction of a segmental long bone defect. PATIENTS AND METHODS: Between 1983 and 2005, 19 patients who had undergone wide resection of a tumor close to the knee followed by reconstruction with a massive endoprosthesis were revised for a diagnosis of stiffness. RESULTS: The mean age of the patients was 12 years (range: 7-19 years). Patients were followed for a mean five years (range: 1-21 years). Three patients were not assessed at the last follow up (two patients died, one patient was amputated for a local recurrence). The mean range of motion improved 80+/-24 degrees preoperatively to postoperatively. The Enneking score improved from 15+/-0.5 to 23+/-3 points at three months follow-up, and to 22+/-5 at last follow-up. Recurrent stiffness occurred three times and required a second operative release with a good final result. DISCUSSION: Outcome depends on the cause of the stiffness of the reconstruction knee arthroplasty. Stiffness can be caused by complications (trauma, implant failure, infection), and patient-related factors (lack of physiotherapy). Open arthrolysis is indicated for chronic stiffness in a motivated patient with an identified cause because failure to identify the cause of stiffness may result in recurrence of the problem.

[Orthopedic treatment of spinal deformities in infancy and early childhood]. / Le traitement orthopédique dans la pathologie vertébrale du petit enfant.

Surgical treatment of spinal deformities in infancy and early childhood (before age 6) is often very useful if the lesion is localized and curable by one unique surgery, such as hemivertebra resection and fusion. On the contrary, if the lesion, whether idiopathic or paralytic, is extended to a large part of the spine, early surgical treatment in infancy gives very disappointing results and often worsens the status of the child, especially respiratory function if the lesion is mainly thoracic. The goal of this paper is to explain in detail indications and management of non-surgical treatment of such lesions. These are variable according to localization, etiology, and associated anomalies, and are mainly based on proper casting (often repeated), bracing (often intermittent between casting) and proper respiratory equipment. From time to time, a surgical treatment is locally indicated, but most of the time results are disappointing and the best is to repeat non-surgical treatment until proper definitive arthrodesis can be performed. This approach is not very rewarding for the child and family, but is clearly better than sudden extensive surgery in early childhood with very severe and disastrous results in adulthood. It is our hope that the recommendations and thoughts presented in this paper will help readers to manage young children using the most efficient, non-aggressive, but long-lasting therapy.

[Surgical treatment of lumbosacral spondylolisthesis with major displacement in children and adolescents: a continuous series of 20 patients with mean 5-year follow-up]. / Le traitement chirurgical du spondylolisthésis lombo-sacré à grand déplacement de l'enfant et de l'adolescent.

PURPOSE OF THE STUDY: This retrospective analysis involved a continuous series of twenty cases of lumbosacral spondylolisthesis with major displacement treated before maturity. We compared our experience using a non-instrumented lumbosacral fusion technique with the results of other techniques proposed in the literature. MATERIAL AND METHODS: We reviewed the cases of twenty children and adolescents who underwent surgery in our unit. For each case, we recorded the clinical history and course to last follow-up. X-rays were studied and manual measurements taken of the different parameters used to analyze the spine. Data were recorded in a database for statistical analysis. Sixteen of the twenty cases showed spinal deformation causing lumbalgia, generally associated with radiculalgia. Mean age at surgical treatment was 13 years 3 months, range 7 years 2 months to 17 years 6 months. All of the children has Meyerding stage 3 or 4 displacement associated with lumbosacral kyphosis. Surgical treatment followed a period of progressive reduction by traction and suspension in lordosis using a hammock. All twenty patients underwent posterolateral arthordesis using a cancellous graft between L4 and the sacrum. The fusion was performed after fashioning a thoraco-lumbo-pelvic cast including both thighs in the position of reduction. A complementary time for anterior arthodesis was needed for eight patients. RESULTS: The postoperative period was uneventful in twelve patients. Two children developed intestinal obstruction with a peritoneal bridle. Three children had an L5 radicular deficit and three sphincter disorders. All neurological disorders resolved in a few months. At mean postoperative follow-up of 5 years 3 months, the arthrodesis appeared to be fused in 19/20 cases. Only one patient presented a lucent line in the zone of the bone graft suggesting possible fibrous nonunion. Eighteen patients were symptom free and led a normal life. Two patients complained of moderately bothersome lower back pain. DISCUSSION: Many of the children in our series had major lumbosacral dysplasia with a verticalized sacrum, aggravating the lumbosacral kyphosis. This led to an increased pelvic tilt and decreased sacral slope. Progressive preoperative reduction of the lumbosacral kyphosis allowed conducting the lumbosacral fusion under favorable conditions. We did not open the spinal canal and avoided the mid line in order to protect as much as possible posterior spinal stability and preserve all the bone surfaces receiving the posterolateral graft. We reserved indications for complementary anterior lumbosacral arthrodesis to the most exaggerated cases of lumbosacral kyphosis. The therapeutic program is long due to the progressive preoperative reduction and the strict period of immobilization after surgery. In our experience, this approach allows quality lumbosacral fusion with good correction of the lumbosacral kyphosis. Neurological complications remain frequent and can occur during even slow progressive reduction.

Anatomical study of the paraspinal approach to the lumbar spine.

The original description of the paraspinal posterior approach to the lumbar spine was for spinal fusion, especially regarding lumbosacral spondylolisthesis treatment. In spite of the technical details described by Wiltse, exact location of the area where the sacrospinalis muscle has to be split remains somewhat unclear. The goal of this study was to provide topographic landmarks to facilitate this surgical approach. Thirty cadavers were dissected in order to precisely describe the anatomy of the trans-muscular paraspinal approach. The level of the natural cleavage plane between the multifidus and the longissimus part of the sacrospinalis muscle was noted and measurements were done between this level and the midline at the level of the spinous process of L4. A natural cleavage plane between the multifidus and the longissimus part of the sacrospinalis muscle was present in all cases. There was a fibrous separation between the two muscular parts in 55 out of 60 cases. The mean distance between the level of the cleavage plane and the midline was 4 cm (2.4-5.5 cm). In all cases, small arteries and veins were present, precisely at the level of the cleavage plane. We found it possible to easily localize the anatomical cleavage plane between the multifidus part and the longissimus part of the sacrospinalis muscle. First the superficial muscular fascia is opened near the midline, exposing the posterior aspect of the sacrospinalis muscle. Then, the location of the muscular cleft can be found by identifying the perforating vessels leaving the anatomical inter-muscular space.

Outcome of flat bone sarcomas (other than Ewing's) in children and adolescents: a study of 25 cases.

We analysed the clinical features and outcome of young patients with non-Ewing's flat bone sarcoma treated during the era of contemporary chemotherapy. The characteristics and outcome of 25 patients (15 males and 10 females) with primary or radiation-related flat bone sarcoma treated in the Pediatrics Department at the Institut Gustave Roussy from 1981 to 1999 were reviewed. In all, 20 patients had osteosarcoma, four chondrosarcoma and one malignant fibrous histiocytoma. The age at diagnosis ranged from 2 to 23 years (median, 15 years). Nine tumours were located in the craniofacial bones, 11 in the pelvis and five in flat bones at other sites. Four patients had metastatic disease at diagnosis. Radiation-associated flat bone osteosarcoma was diagnosed in 10 out of 25 cases. The projected overall survival and event-free survival (EFS) rates at 5 years were 45.1 and 34.3% for all the 25 patients. The EFS rate of patients with second bone sarcoma was similar to that of patients with de novo flat bone sarcoma (P=0.1). The aim of treatment was curative for 24 patients, 23 of whom were treated with intensive chemotherapy regimens and 19 with surgery. Significant adverse prognostic factors on survival included incomplete surgical resection (P=0.001) and use of regimens without pre- and postoperative chemotherapy (P=0.007). Nine of the 25 patients were treated with pre- and postoperative chemotherapy and complete surgical resection. Among them, eight are alive with no disease. Radical surgical resection is the overriding prognostic factor for flat bone sarcomas in young patients. Nevertheless, our results suggest a more favourable outcome since the advent of intensive chemotherapy.

3D finite element simulation of Cotrel-Dubousset correction.

The Cotrel-Dubousset (CD) scoliosis surgery was simulated for 10 patients with idiopathic scoliosis using a 3D finite element model (FEM) of the patient's entire spine. The geometry of the FEM was extracted from a 3D stereo-radiographic reconstruction, and mechanical properties were personalized using lateral bending films. Finally, each step of the CD correction was simulated and results were compared with the post-operative 3D stereo-radiographic reconstruction. The whole procedure was applied for 10 patients, and quantitative comparison was performed between post-operative spine configuration and predicted configuration. For all patients, mean differences between post-operative measurements and predicted values of vertebral rotation were estimated at 5 degrees (max: 13 degrees) and those for linear position at 6 mm (max: 12 mm). Furthermore, intermediate steps of surgery simulation were consistent with the literature. Then, for one scoliotic patient, the model was used to investigate three alternative surgical strategies. It was found that a one-level change in the instrumentation limit may have a significant effect on spine alignment and correction.

Intralesional Ethibloc injections in primary aneurysmal bone cysts: an efficient and safe treatment.

OBJECTIVE: Ethibloc is a fibrogenic and thrombogenic agent recently proposed for the treatment of bone cysts. The purpose of this study is to report the results of direct Ethibloc injection in primary aneurysmal bone cyst (ABC) in children. DESIGN AND PATIENTS: Seventeen patients, aged from 2 to 18 years (mean 8 years), were treated with either a single injection (14 patients) or supplementary injections (3 patients) of Ethibloc. The histological diagnosis was assessed following surgical biopsy and was retrospectively reviewed. The mean follow-up was 5 years (range 18 months to 11 years). RESULTS: At 5 year follow-up, 14 of 17 patients demonstrated complete healing manifest by increased cortical and septal thickening. Surgical excision was required in three patients, in two of whom the ABC increased rapidly in size despite the injection, and in one of whom the healing was incomplete. We observed inflammatory reactions in 16 of 17 patients with local pain and fever. Three patients developed a small cutaneous fistula which resolved spontaneously in a few weeks. No major complications such as deep infection, pulmonary embolism, epiphyseal necrosis or malignant degeneration were observed. CONCLUSION: Percutaneous direct Ethibloc injection is a safe, efficient and noninvasive treatment for ABC. The authors highlight the frequent local reactions.

Explicit calibration method and specific device designed for stereoradiography.

The three-dimensional geometry of the human spine is noteworthy information that can be obtained by stereoradiographic methods. These methods are based on the identification of anatomical structures in several views which are obtained by rotation of a patient standing on a turntable. Calibration algorithms for computer vision or photogrammetry are well documented, but they generally yield calibration devices which are cumbersome for the use in clinical stereoradiography. This paper presents a calibration method adapted to a two-view stereoradiography calibration (frontal and lateral incidences) and based on a simplified geometric modeling of the radiological environment. The a priori knowledge yields four calibration equations related to the vertical and horizontal planes of both views, leading to a specific calibration procedure and device. Moreover this device is attached to the stereoradiographic system (directly integrated on the turntable) in order to facilitate clinical applications. A validation was performed on 26 dried lumbar vertebrae in order to evaluate clinical situation. The mean accuracy of the stereoradiographic reconstruction was 1.2mm.