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Intraoperative intra-articular imaging for femoroacetabular impingement: ct vs mri comparison with arthroscopic findings - старонка 18


Results

The positions of 244 screws were noted on postoperative scans; 29 protruded into the spinal canal. The classical unique stimulus technique detected three of these screws with a limit threshold of 12mA. The train of stimuli technique detected 25 of the 29 malpositioned screws with a proposed threshold of 30 mA; the negative predictive value was 97.7% but with a high rate of false positives. With a 15 mA threshold, the positive predictive value was 64.2%. The two techniques detected better screws that entered the canal at levels other than the apex of the scoliotic curvature.

Discussion

Intraoperative monitoring during the implantation of thoracic pedicle screws with trains of stimuli is more precise than with unique stimuli for detecting screw in the canal. We recommend using the two techniques, considering that train stimulation does not detect radicular lesions. We propose the 15 mA stimulation threshold for the train stimuli technique to identify screws protruding into the spinal canal and a level of uncertainty between 15 and 30 mA, which should be completed by intraoperative radiographic techniques.

164

Evoked potential monitoring during surgery for scoliosis with syringomyelia: usefulness of the epidural probe

Franck Accadbled*, Patrice Henry.

* Corresponding author: Service d'Orthopédie. Hôpital des Enfants.330 avenue de Grande Bretagne 31059 Toulouse France

Purpose of the study

Neurological complications of scoliosis surgery are more common in patients with syringomyelia. To limit the risk, evoked potentials monitoring was developed in the 1980s. We used a multimodal monitoring technique based on the use of an epidural probe. The purpose of the present work was to analyse the results of this method.

Material and methods

This as a prospective series of nine patients with scoliosis associated with syringomyelia who underwent surgery for posterior instrumentation from 2001 to 2009. Mean age was 15.3 years (13.8-16.8). Three patients had had prior surgery for Chiari deformity. One patient presented minimal signs of a pyramidal syndrome. There were four cases of left thoracic scoliosis. The mean Cobb angle of the predominant curvature was 61° (40-86°). Intraoperative evoked potentials monitoring was systematic using an epidural electrode which recorded both the somesthesic evoked potential (SEP) and the cord stimulation creating the neurogenic evoked potentials (NEP).

Results

Electrophysiological monitoring was successfully achieved in all patients for at least two of the four possible modalities. In five patients, the cortical SEP responses were absent or of insufficient amplitude. False positive cortical response was observed in one patient, false subcortical response in three patients, and false positive response for both in one patient. Medullary SEP and NEP remained unchanged in all other patients. There were no false negatives nor any true positives and no awakening test was performed. The mean Cobb angle of the predominant curvature was 24° postoperatively (10-40°). The postop neurology exam was unchanged from the baseline exam in all patients.

Discussion and conclusion

Scoliosis is often the only clinical manifestation of syringomyelia. Syringomyelia can nevertheless perturb cortical and subcortical evoked potentials. The risk of a neurological complication is greater in these patients and an awakening test can be recommended. Use of an epidural probe allows reliable monitoring in all patients, avoiding an awakening test. Surgical correction can thus be optimised.

165

Idiopathic scoliosis in adolescents: what is the most appropriate correction ?

Benjamin Blondel*, Jean-Luc Jouve, Virginie Lafage, Samuel Jacopin, Gerard Bollini.

* Corresponding author: Service d'orthopedie pediatrique Hopitale Timone Enfants

(Ecole doctorale 463, UMR CNRS 6233, sciences du mouvement humain)

264 rue saint pierre 13005 Marseille France

Purpose of the study

Instrumented all-screw fusions for idiopathic scoliosis in adolescents can provide good coronal correction. Nevertheless, compared with hybrid instrumentations, these all-screw assemblies also cause a loss of kyphosis, which itself has a flattening effect on lordosis. The purpose of this work was to compare, within a series of hybrid instrumentations, outcome between mono- and poly-axial screws.

Material and methods

Sixty patients (mean age 14.7 years) with Lenke type 1-2 scoliosis were included in this study and analysed retrospectively. The surgery consisted in a hybrid instrumentation with a lamolaminal compression clamp cranially, pedicle screws between the last instrumented vertebra and T11 caudally, and infra-laminal connections on the intermediary levels. Mono-axial screws were used for the first 30 patients and poly-axial screws for the 30 following patients. Student’s t test was used to compare the two surgical strategies in terms of Cobb’s angle correction and change in T4-T12 kyphosis three months postop.

Results

Considering the entire series, preoperative parameters were not significantly different (p>0.05). At last follow-up, the residual Cobb angle was significantly greater (p<0.04) in the polyaxial group (20.3±8.2°) than in the monoaxial group (15±5°), with 64.8±9.1% correction in the polyaxal group and 72.1±7.6% in the monoagial group. IN the sagittal plane, there was a significant difference (p<0.04) between thoracic kyphosis in the polyaxial group (26.6±7°) and the monoaxial group (23±6.2°).

Discussion

The importance of the spinal balance in the sagittal plane is widely described in the literature. Sagittal imbalance, particularly arising from an iatrogenic cause, is correlated with poorer clinical outcome in spinal deformities in the adult. These preliminary data show that even with hybrid assemblies known to produce less flat back exhibit differences depending on the technique used. It is thus of fundamental importance to carefully choose the desired surgical correction. In our opinion, it would be preferable to place priority on correction in the sagittal plane, accepting a slight diminution in the correction in the coronal plane. Further study with longer follow-up is needed to confirm these early results.

166

Correction of major scoliosis (>90°) with exclusively posterior Smith-Petersen osteotomy and pedicular screws

Pedro Doménech*, Jane Hoashi, Ramon Navarro, Jesús Burgos, Gabriel Pizá, Ignasi Sanpera, Jose Maruenda.

* Corresponding author: Maestro Alonso 109

S. de COT infantil

H. G. U. Alicante 03010 Alicante Spain

Purpose of the study

The conventional surgical technique for major scoliosis requires a double posterior and anterior two-phase procedure. We describe here a standardized method for 3D correction of curvatures with a Cobb angle >90° via a unique posterior approach, with simultaneous derotation and alignment in two planes.

Material and methods

This was a prospective series of 19 patients with severe scoliosis measuring >90° with pre- and postop x-rays and CT-scans. Mean follow-up was 4.1 years (2-6), mean age 16 years. Data were processed with SPSS software using non-parametric tests. Surgical technique. Via a posterior approach, pedicle screws were inserted bilaterally at each level with a Smith-Petersen osteotomy at the apex. The deformity was reduced by aligning the pedicles on the convex side using a co-planar system (Spine June 1998). A rod was then placed on the concave side and incurved before removing the prolongation tubes. A convex rod was then positioned to terminate the assembly.

Results

On average, there were 5.6 osteotomies (4-8). The spine was fused with the pelvis in 14 patients. Mean correction in the frontal plane was 70%, with mean improvement from 106° to 32° (p<0.001). In all cases, normal values were obtained for the sagittal plane after correction. Mean loss of correction at last follow-up was 4%. Rotation of the apical vertebra improved relative to the sacrum from mean 4° to mean 22° postop (p<0.001). The CT-scan disclosed 16% mal positioned screws, 73% of them around the apex and in vertebra close to T4. There were no neurological sequelae.

Discussion

In the conventional treatment, the anterior approach allows more spinal flexibility, but at the cost of associated morbidity. With the insertion of pedicle screws at every level, together with Smith-Petersen osteotomy, the inherent morbidity of the double approach can be avoided.

Conclusion

Major scoliosis can be treated with pedicle screws at each level, with an acceptable rate of malpositioned screws, and without permanent neurological complications. This technique allows satisfactory corrections of severe deformity by associating pedicle screws with posterior osteotomy.

167

Mid-term results of lumbosacral arthrodesis for severe neurological scoliosis instrumented with the simplified Jackson technique

Jean-baptiste Néron*, Christian Bonnard, Charlotte Debodman, Benoit De courtivron, François Bergerault.

* Corresponding author: service d'orthopédie 2C - CHU trousseau

av de la république 37170 Chambray les tours France

Purpose of the study

For the treatment of severe neurological scoliosis, extended arthrodesis enables greater comfort for the patient and caregivers. Lumbosacral fusion is problematic in these patients with major deformities because of the poor quality of the bone stock and the cumbersome material. In 1990, Jackson described a lumbosacral fusion technique using an S1 screw and intra-sacral rods linked to the assembly by connectors and inserted under radiographic guidance, producing a highly resistant instrumentation. The purpose of this work was to evaluate the radiographic and clinical outcome of the simplified Jackson technique performed without radiographic guidance or connectors.

Material and methods

Thirty-three patients underwent extended arthrodesis with lumbosacral instrumentation using the simplified Jackson technique. These patients were studied with minimum four years follow-up (mean 82 months). Frontal and sagittal balance, Cobb angle, sacral slope, lumbar lordosis, and frontal obliquity of the pelvis were studied on the preop, postop and last follow-up x-rays. Postoperative complications were noted.

Results

Complete fusion was obtained in 32 patients. One patient had to have revision surgery due to displacement of a sacral rod, one for displacement of a thoracic hook, and two patients for removal of material after late infection. At last follow-up, none of the patients exhibited pain related to the spinal assembly. The mean Cobb angle improved from 62° to 20° postoperatively and 24° at last follow-up. The frontal obliquity of the pelvis was 10.2° (0-26°) preoperatively and was corrected on average to 7.5° (024°) postoperatively. Mean secondary loss of correction was 1.2° (0-9°) (16%). Correction of the sacral slope towards a reference value of 40° was on average 11.2° with 0.2° (0-18°) loss of correction at last follow-up. The standard deviation for lumbar lordosis was 29 preoperatively and 15 after correction. It was 17 at last follow-up with a tighter range around a stable mean at 40°.

Discussion

Correction of the spinal parameters was comparable to that obtained with other techniques reported in the literature such as Miladi and Yaziçi and the Luqué-Galvestone technique with less secondary loss of correction. The results are comparable with those reported by Mazda in 1997 using the non-simplified Jackson technique.

Conclusion

The simplified Jackson technique is a simple reliable solution for the correction of extended neurological scoliosis, with results that persist over time.

168

Is there a long-term change in the position of the cord after surgical correction of scoliosis ?

Fernando Aranda*, Jesus Burgos, Pedro Doménech, Daniel Jimenez, Maria S. Del Cura, Eduardo Hevia, Carlos Barrios, Jose Maruenda.

* Corresponding author: Calle carabela 10 5 B 28042 Madrid, Spain

Purpose of the study

According to a review of the literature, the position of the spinal cord would whinge after surgical correction of scoliosis. Knowledge of the precise position of the thoracic cord in scoliosis would facilitate insertion of pedicle screws, improve neurophysiological monitoring, and make it possible to know whether a malpositioned screw in the canal could produce long-term injury if the postoperative cord displacement occurs.

Material and methods

Prospective study of 10 patients operated on for idiopathic Lenke I scoliosis with mean Cobb angle 62° (50-72°). Mean age at surgery was 16.1 years (12-24). Apex was T8, T9, or T10. We measured, at the apex of the curvature, the distance of the cord from the pedicle on the convex and concave sides using MRI axial slices, preoperatively, postoperatively and at last follow-up. Scoliosis was corrected with pedicle screws at all levels excepting the apex vertebra to avoid interference on the MRI images.

Results

At mean 55 months follow-up (41-61), the radiographic study showed mean improvement of 82% in the anteroposterior plane with a mean Cobb angle of 12° (6-20°); correction of rotation was 61%. Preoperatively, the mean distance at the apex from the medial border of the pedicle on the convex side to the dural sac was 0.77 cm (0.6-1 cm); this distance was 0.74 cm on the postoperative images. On the concave side, the mean distance was 0.04 (0.00-0.09) preoperatively and 0.03 (0.00-0.08) postoperatively. The difference was not significant. At the end of follow-up, the final MRI showed a mean distance from the pedicle to the dural sac of 0.76 cm (0.6-1 cm) on the convex side and 0.04 (000-0.08 cm) on the concave side.

Conclusion

The preoperative situation of the cord, displaces towards the concave side, is not modified long after surgical correction of significant scoliosis. In patients who undergo surgery before bone maturity, the position of the cord preoperatively also does not change during growth.

169

Does gait with medialised patella in the spastic diplegic child result from excess femoral anteversion ?

Anne laure Simon*, Brice Ilharreborde, Cindy Mallet, Ana Presedo, Keyvan Mazda, Georges françois Penneçot.

* Corresponding author: 48 bd sérurier 75019 Paris France

Purpose of the study

Internal rotation of the hip joint is usually associated with excessive femoral anteversion and a patella in a medialized position. But this is a purely clinical observation. The purpose of our study was to demonstrate that kinematic data must be associated with the clinical data.

Material and methods

This was a retrospective study of 376 lower limbs in spastic diplegic children. We retained 206 medialized patellae for review. We noted from the gait analysis video films, at 30% of the gait cycle, the position of the patella, hip rotation, and pelvis rotation. We then noted from the analytical exam performed the same day, internal rotation of the hip joint.

Results

59% of the patellae were medialized. Among the 206 patients, 71.4% had internal rotation of the hip joint at the physical exam but, on the kinematic films, only 40% had internal rotation of the hip joint, but 50% had internal rotation of the pelvis. Among the 206 patients, 28.6% did not have excessive internal rotation of the hip joint at the physical exam, 28% had normal rotation, 21% had external rotation.

Discussion

The medialized position of the patella is not synonymous with excessive femoral anteversion since pelvic rotation explains alone the medial position of the patella in 50% of cases, without internal rotation of the hip as demonstrated by the kinematic data. Our findings show that physical exam alone, or inversely, kinematic data alone, cannot adequately explain rotational disorders of the pelvis-hip segment. Moreover, when the hip does not exhibit excessive internal rotation clinically in patients with a medialized patella, the explanation lies in excessive internal rotation of the pelvis or abnormal muscle activity.
2014-07-19 18:44
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