Assessment of the tolerance angle for pedicle screw insertion.

Cannulation process intervenes before implantation of pedicle screw and depends on the surgeon's experience. A reliable experimental protocol has been developed for the characterization of the slipping behavior of the surgical tool on the cortical shell simulated by synthetic materials. Three types of synthetic foam samples with three different densities were tested using an MTS Acumen 3 A/T electrodynamic device with a tri-axis 3 kN Kistler load cell mounted on a surgical tool, moving at a constant rotational speed of 10° mm-1 and performing a three-step cannulation test. Cannulation angle varied between 10° and 30°. Synthetic samples were scanned after each tests, and cannulation coefficient associated to each perforation section was computed. Reproducibility tests resulted in an ICC for Sawbone samples of 0.979 (p < 0.001) and of 0.909 (p < 0.001) for Creaplast and Sawbone samples. Cannulation coefficient and maximum force in Z-axis are found the best descriptors of the perforation. Angular threshold for perforation prediction was found to be 17.5° with an area under the curve of the Receiver Operating Characteristic of 89.5%. This protocol characterizes the cannulation process before pedicle screw insertion and identifies the perforation tool angle until which the surgical tool slips on the cortical shell depending on bone quality.

Change of vertebral orientation, between the supine position and the prone position.

PURPOSE: Our aim was to assess the change of vertebral orientation, expressed in the sagittal plane, in the transversal plane and in the frontal plane, at each level from T1 to S1 between the supine position (like in in a CT scan) and the prone position lying on bolsters like in an OR. METHODS: Thirty-six patients were selected and included for a total number of one hundred and forty-eight vertebral levels. There were 30 females and 6 males. The mean age was 15 years and 9 months. A semi-automatic image processing technique and software (3D slicer), with a custom-made python script add-on, was used for each patient: paired preoperative CT scan and intraoperative cone beam computed tomography (CBCT) scan were processed to acquire complete spinal reconstructions in a consistent 3D coordinate system. The aim was to automatically compute a set of sagittal, transversal, and frontal rotations of each vertebral level of the same patient describing the 3D vertebral rotation between the supine position and the prone position lying on bolsters. RESULTS: For sagittal analysis, the results showed a behavior in the evolution of rotation depending on the level. Between T01 and T10, the rotation was between - 14° and - 8°. Between T10 and L05, the sagittal rotation increased from - 10° up to + 10°. For frontal and transversal analysis, the rotations were under 6.5°. CONCLUSION: These results could be valuable to perform a safe virtual templating: the information given by the virtual templating seems to be more accurate in the transversal plane than in the sagittal plane.

Sliding on cortical shell: Biomechanical characterization of the vertebral cannulation for pedicle screw insertion.

BACKGROUND: Pedicular screws pull-out has been well studied unlike their insertion. A need for characterizing cannulation before pedicle screw implantation is highlighted in literature and offers promising prospects for future intra-operation instrumentation. A reliable cannulation protocol for ex-vivo testing in swine and cadaver vertebrae is presented in this work to predict extra pedicular perforation. METHODS: An MTS Acumen 3 A/T electrodynamic device, with a tri-axis 3 kN Kistler load cell mounted on a surgical tool was used to reproduce surgeon's gesture by moving at a constant rotational speed of 10°/mm and performing a three-section test. Perforation of the pedicle's cortical shell was planned through a design of experiment on the surgical tool angle at the entry point. Samples were scanned before and after mechanical tests and reproducibility of the protocol was tested on synthetic foam. Computation of the angle between cannulation tool and pedicle cortical shell was performed as well as cannulation coefficient of each perforation section. FINDINGS: A total of 68 pedicles were tested: 19 perforated and 21 non-perforated human pedicles, 17 perforated and 16 non-perforated swine pedicles. The reproducibility of the protocol for cannulation coefficient computation resulted in an intraclass correlation coefficient of 0.979. Cannulation coefficients results presented variability within spinal levels as well as between swine and human model. Correlation between bone density and cannulation coefficient was found significant (p < 0.005). Torque measurement was found to be the best predictor of perforation. Threshold of angle for prediction of perforation was found to be 21.7°. INTERPRETATION: Characterizing pedicle cannulation enables to predict extra pedicular perforation. Influence of bone mineral density and patient-specific morphology on pedicle cannulation has been highlighted together with a comparison of swine and cadaver models.

Genu valgum in Legg-Calvé-Perthes disease treated with femoral varus osteotomy.

UNLABELLED: Femoral varus osteotomy is one of the most common treatments for patients with symptomatic Legg-Calvé-Perthes disease with more severe deformities. We hypothesized knee valgus alignment at maturity in patients with Legg-Calvé-Perthes disease is an effect of the disease and not an effect of femoral varus osteotomy. We retrospectively compared matched groups of 28 patients with and without femoral varus osteotomy. The two groups were similar with respect to age at onset and classification of Herring et al. The distribution of valgus alignment among patients who had surgery and patients who did not have surgery was assessed at maturity and was similar between the operative and nonoperative groups. The data suggest valgus malalignment (genu valgum) is not a side effect of femoral varus osteotomy in patients with Legg-Calvé-Perthes disease, but rather an effect of the disease. LEVEL OF EVIDENCE: Level III, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Congenital dislocated spine: implications for orthopaedic management.

BACKGROUND: Congenital dislocation of the spine (CDS) is a rare malformation due to a developmental failure of the spine and the spinal cord at a single spinal level. New embryological and physiopathological findings define CDS as an autonomous entity compared with multilevel pathologies. The severity of CDS neurological outcome requires its treatment by experienced pediatric spine surgeons in a pediatric specialty hospital. This report aims to propose a comprehensive orthopaedic management strategy and operative technique of CDS in 6 new patients. METHODS: The records of patients treated at our institution for congenital anomalies of the spine were reviewed in a retrospective study. Inclusion criteria were extracted from the actual context of new embryologic theories: single level involvement; sudden mainly sagittal vertebral displacement with anterior translation of the entire cranial vertebral column on the caudal vertebrae ("step-off sign"); underlying spinal malformation at a clearly distinct level; spinal cord intact both cranial and caudal to the malformation; possibility of malformed aspect of the 2 involved vertebrae. Demographic data, family, and clinical history were collected. Complete set of plain radiographs and modern imaging computed tomography and magnetic resonance imaging were analyzed. RESULTS: Six children treated between 1993 and 2007 have been classified as CDS. The mean follow-up to date of the 4 patients alive after the last corrective surgery is 9.8 years (range, 1-14.6 years). All patients alive have at follow-up solid stable fusion and no progression of spinal deformity. Two of the patients are independent walkers. CONCLUSIONS: The neurological involvement of CDS if present initially is the consequence of an associated spinal cord malformation without mechanical factor. Adaptation of the therapeutic strategy may avoid secondary neurological damage. Parents should be counseled as soon as the diagnosis is made, the obstetrical and postnatal orthopaedic management has to be adapted. Stabilization of the spine including very early cast immobilization and an early instrumented decompression-stabilization with circumferential fusion in 1 stage is required.

Symptomatic os trigonum in children.

BACKGROUND: Symptomatic os trigonum is a rare condition well described in adults responsible for chronic ankle pain. To date there is no published case of successfully managed symptomatic os trigonum in children. METHODS: We retrospectively reviewed 4 paediatric patients (11-17) successfully operated on for a symptomatic os trigonum through a postero medial approach. One case was bilateral. RESULTS: Pain relief was postoperatively obtained in all cases. All of the patients were able to return to physical activities after 3 months. The mean follow up was 12 months. CONCLUSION: Symptomatic os trigonum may be responsible for chronic ankle pain in children and adolescents as well as in adults. The surgical treatment is effective in children.

Rotational profile of the lower limb in 1319 healthy children.

Lower limb rotational profile in children may cause great concern to parents and relatives. In order to give parents clear information, there is a need for referential studies giving normative data of lower limb rotational profile and its normal changes expected over growth. Our aim was to collect a large clinical series of healthy children, out of a clinic, selected from a non-consulting population and to analyse Tibial Torsion and Femoral Anteversion according to age and gender. One thousand three hundred and nineteen healthy children underwent a clinical evaluation. Tibial Torsion was assessed using the method described by Staheli and Engel, whereas Femoral Anteversion was assessed using the method described by Netter. Our results showed that there was a significant difference between males and females in Femoral Anteversion, whereas there was no significant difference between the right side and the left side. Femoral Anteversion was higher in females, and was markedly correlated with age in both genders. There was no significant difference between males and females in Tibial Torsion, nor significant difference between the right side and the left side. Tibial Torsion was slightly correlated with age in both genders. Normative data were statistically defined in this work using the +/-2S.D. range. To our knowledge, there is no large and comprehensive series in the English speaking literature that gives normative data of Femoral Anteversion. Concerning Tibial Torsion, our results compared to those published in the literature.

Neurological classification in myelomeningocele as a spine deformity predictor.

In myelomeningocele, spinal deformities are responsible for major disability. Our aim was to check the predictive power for future spine deformity of a neurological classification applied at 5 years of age. We classified patients into four groups according to their neurological examination made at the age of 5 years. Groups were defined as follows: group I, L5 or below (meaning that all the patients in this group have a paralysis that at least leaves the L5 segment intact); group II, L3-L4; group III, L1-L2; group IV, T12 and above (meaning that all the patients in this group have a paralysis that reaches T11 or above). One hundred and sixty-three patients were included. The results showed that group I is a predictor for the absence of spinal deformity. Group III or IV is a predictor for spinal deformity. Group IV is a predictor of kyphosis. It was previously known that the higher the neurological level, the higher the rate of spinal deformity at maturity, but no work had given physicians a guideline to assess the spinal prognosis in myelomeningocele patients. Our work showed, on the basis of this classification made at the age of 5 years, that future spinal disorders may be expected in some patients, while no spinal deformity may be expected in some others. Thus, an appropriate therapeutic strategy and follow-up can be planned.

Osteochondrosis of the medial malleolar epiphysis: A case report and review of the literature.

INTRODUCTION: Osteochondrosis is characterized by a disturbance of enchondral ossification in skeletally immature patients and should be investigated in children having a history of persistent foot and ankle pain. Involvement of the medial malleolar epiphysis is rarely reported. PRESENTATION OF CASE: We describe the case of a sporty 12-year-old male with osteochondrosis of the left medial malleolar epiphysis treated with a conservative management. DISCUSSION: Calcanear, navicular and metatarsal apophysis are the most common locations for osteochondrosis in ankle and foot. Anyway other osteochondrosis should be excluded. Medial malleolar osteochondrosis is occasionally described. We performed a review of the relevant literature and we summarized clinical aspects, radiological characteristics and reported management of this painful and probably underestimated condition. CONCLUSION: Medial malleolar osteochondrosis is a rare but well recognized condition. Only seven cases are described in literature.

Osteochondral alteration in a child treated with levetiracetam: a rare case of juvenile osteochondritis dissecans of the talar head.

Levetiracetam is a relatively novel antiepileptic drug used for the treatment of partial and generalized seizures in adult and children. Several animal studies describe a possible drug adverse effect on skeletal growth and metabolism. We present a case report of a 10-year-old female child who underwent a prolonged 7-year treatment with levetiracetam for sporadic secondary convulsions secondary to enterovirus encephalitis at the age of 15 months. This patient developed an osteochondritis dissecans lesion (OCD) of the talar head well treated conservatively. Only a few cases have been described of this rare type of OCD. We hypothesize a possible association between levetiracetam therapy and OCD development, suggesting the importance of long-term control of bone growth in levetiracetam-treated pediatric populations.

[Scoliosis in children]. / Scoliose de l'enfant.

The diagnosis of scoliosis is based on the association of kyphosis, vertebral rotation, and lateral deviation of the spine. The clinical examination has to be rigorous in order to rule out a potential etiology for this tridimensional deformity. The assessment of the growth, and of the progressive nature of the scoliosis, is essential before any treatment. For minor deformities, a simple clinical monitoring will be necessary. On the other hand, for moderate deformities, a non-surgical treatment with brace will be recommended. Finally, for severe deformities, the treatment will be a surgical treatment. Surgery will consist of a spinal arthrodesis.

Anatomical study of the proximal femur in the fetus.

Two angles effectively describe the upper femur geometry: The neck shaft angle (NSA) and anteversion (AV). AV and NSA decrease from birth until they reach their adult values, but little work has focused on in-utero life. Our aim was to determine if and how AV and NSA change through the fetal life. Eighty-seven femurs from 44 formalin preserved fetuses were sampled to achieve a biometry. Correlation tests and linear regression showed that AV was highly correlated with age: AV increases during the second half of gestation. No conclusion can be given concerning NSA. It is speculated that these changes may be caused by mechanical stresses.

Bilateral osteochondrosis of the distal tibial epiphysis: a case report.

Osteochondrosis is a developmental disease characterized by an alteration of endochondral ossification. Genetic causes, repetitive mechanical stresses, vascular abnormalities, hormonal imbalances, and interruption of the blood supply to the epiphyseal cartilage are all described causes of osteochondrosis and the etiology is probably multifactorial. Osteochondrosis can occur in different apophysis and epiphysis in all immature skeletons. Distal tibial epiphysis is rarely involved and most of the time unilaterally. We report on an 11-year-old female with bilateral osteochondrosis on distal tibial epiphysis. Only one other similar case has been described in the literature to date.

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.

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.

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.

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.

Isolated capitate shortening osteotomy for the early stage of Kienböck disease with neutral ulnar variance.

BACKGROUND: Kienböck disease is an aseptic necrosis of the lunate for which the treatment is still debated, particularly in the rare cases with neutral ulnar variance. One option is to perform a capitate shortening osteotomy associated with a capitate-hamatum arthrodesis. The aim of this study was to evaluate a simple capitate osteotomy without arthrodesis. METHODS: This is a retrospective study of 11 cases. All patients had a mild form of Kienböck disease (stage I to IIIA according to the classification of Lichtman). A shortening capitate osteotomy was performed through a dorsal medial approach and fixed with staples. RESULTS: At the final follow-up evaluation (mean, 67.4 months), the mean visual analogue scale score was 1.7 (range, 0 to 7). Based on the Nakamura score, the authors obtained six good, two fair, and three poor results. Mean strength improvement was 25 percent compared with the healthy side, and the authors observed no change in range of motion. The radiologic follow-up showed no difference in either the Stahl or the Youm index between preoperative and postoperative measurements. No complication was observed; however, in two cases, the result was evaluated as poor and a revision procedure was performed. CONCLUSION: This technique is a simple and reliable method with which to manage the early stages of Kienböck disease with neutral ulnar variance.

Severe hip infection after a prophylactic contralateral fixation in slipped upper femoral epiphysis: a case report.

The rate of infection is extremely low after a prophylactic contralateral fixation in slipped upper femoral epiphysis, and exclusively involves superficial wound infection. We report an unusual case of hip infection after a prophylactic pinning with a single cannulated screw. The evolution was unfavorable, with necrosis and epiphysiolysis of the femoral head. A total hip arthroplasty was performed after 1 year of evolution.