Thibault Lenoir

Is there a sagittal imbalance of the spine in isthmic spondylolisthesis? A correlation study

Recent studies suggested a predominant role of spinopelvic parameters to explain lumbosacral spondylolisthesis pathogeny. We compare the pelvic incidence and other parameters of sagittal spinopelvic balance in adolescents and young adults with developmental spondylolisthesis to those parameters in a control group of healthy volunteers. We compared the angular parameters of the sagittal balance of the spine in a cohort of 244 patients with a developmental L5–S1 spondylolisthesis with those of a control cohort of 300 healthy volunteers. A descriptive and correlation study was performed. The L5 anterior slipping and lumbosacral kyphosis in spondylolisthesis patients was described using multiple regression analysis study. Our study demonstrates that the related measures of sagittal spinopelvic alignment are disturbed in adolescents and young adults with developmental spondylolisthesis. These subjects stand with an increased sacral slope, pelvic tilt and lumbar lordosis but with a decreased thoracic kyphosis. Pelvic incidence was significantly higher in spondylolisthesis patients as compared with controls but was not clearly correlated with the grade of slipping. We showed the same “sagittal balance strategy” in spondylolisthesis patients as in the control group regarding correlations between pelvic incidence, sacral slope, pelvic tilt and lumbar lordosis. We believe that the lumbosacral kyphosis is a stronger factor than pelvic incidence which need to be taken into account as a predominant factor in theories of pathogenesis of lumbosacral spondylolithesis. We thus believe that increased lumbar lordosis associated with L5–S1 spondylolisthesis is secondary to the high pelvic incidence and is an important factor causing high shear stresses at the L5–S1 pars interarticularis. However, the “local” sagittal imbalance of the lumbosacral junction is compensated by adjacent mobile segments in the upper lumbar spine, the pelvis orientation and the thoracic spine. The result is not optimal but a satisfactory global sagittal balance of the trunk, even in the most severe grade of slipping.

Paraplégie secondaire à une infiltration épidurale interlamaire lombaire, à propos d'un cas

We report the first case of paraplegia observed after epidural steroid injection in the upper spine. The patient was a 42-year-old male who underwent surgery two years earlier for stenosis of the lumbar spine from L2 to the sacrum leading to early manifestations of an equina cauda syndrome. This first operation provided satisfactory function with complete resolution of the objective neurological symptoms. The patient later developed bilateral radiculalgia involving the L3 and L4 territories and was treated by radio-guided epidural steroid injection (125 mg hydrocortancyl) delivered in the L1-L2 interlaminar space. The injection was achieved with no technical difficulty and there was no injury to the dural sac. Immediately after the injection, the patient developed complete motor and sensorial paraplegia from T12. CT and MRI performed 30 min and 4h, respectively, after the accident revealed a medium-sized discal herniation behind the L2 body. No other lesion was observed. Emergency surgery was performed for radicular release but to no avail. The patients neurological status remained unchanged and four days later the T2 MRI sequence revealed a high-intensity intramedullar signal in the cone. The diagnosis of ischemia of the medullary cone was retained, hypothetically by injury to the dominant radiculomedullary artery via an undetermined mechanism. This complication has been previously described after upper foraminal steroid injections but not after intralaminar epidural steroid injection.

Analyse de l’équilibre sagittal du rachis dans les spondylolisthésis dégénératifs

Resume Les objectifs de ce travail ont ete de determiner les parametres caracterisant la statique rachidienne dans le plan sagittal d’un groupe de 70 patients operes pour spondylolisthesis degeneratif et de les comparer avec ceux d’une population de 250 temoins. Les parametres suivants ont ete pris en compte : incidence et version pelvienne, pente sacree, lordose lombaire, cyphose thoracique, gite sagittale T9 et angulation S1-S2. A partir de ces valeurs ont ete effectuees : une analyse univariee afin de preciser les principales caracteristiques de distribution des parametres pris en compte ; une etude multivariee afin d’etudier les variations de ces parametres les uns par rapport aux autres et ainsi de mieux definir les perturbations de l’equilibre sagittal de ces patients ; une comparaison des parametres etudies a ceux d’une population temoin. L’une des caracteristiques essentielles de la cohorte analysee etait la presence d’une forte incidence pelvienne (62,6 versus 54,7). La valeur elevee de ce parametre pourrait etre, par l’intermediaire de l’hyperlordose et de l’augmentation de la version pelvienne qu’elle induit, l’un des facteurs de degenerescence d’une unite fonctionnelle rachidienne et a terme d’un glissement degeneratif. Les determinants les plus significatifs de la gite sagittale T9 etaient : la version pelvienne, l’incidence pelvienne, la lordose lombaire et la lordose locale L4-S1. Un tiers de nos patients etait en situation de gite anterieure essentiellement en raison d’une importante cyphose lombosacree, un tiers avait une gite sagittale T9 normale et un tiers etait en situation de gite posterieure en raison d’une forte cyphose thoracique associee. Ce travail nous a permis de mieux caracteriser les parametres de l’equilibre sagittal du spondylolisthesis degeneratif, d’emettre quelques hypotheses vis-a-vis du mecanisme constitutif de tels glissements degeneratifs et de souligner la diversite des situations d’equilibre de ces patients avec les implications therapeutiques que cela comporte.

Pelvic ring fractures internal fixation: Iliosacral screws versus sacroiliac hinge fixation

INTRODUCTION Pelvic ring fractures are severe injuries whose functional results depend on the quality of reduction. Numerous internal fixation alternatives have been described, but the biomechanical studies comparing them remain rare. HYPOTHESIS This study compared the biomechanical behavior of iliosacral screws (ISS) with sacroiliac hinge type fixation (SIF) following unstable pelvic ring fractures fixation. MATERIALS AND METHODS A lesion simulating sacroiliac disruption and pubic disruption was created on 14 cadaver pelves. After randomization, the fractures were internally fixed using an anterior plate associated with either an ISS or an SIF. The specimens were then submitted to forces applied vertically at the coxofemoral joints. Relative movements in vertical translation and in rotation between the iliac wing and the sacrum, as well as the stiffness and the forces at failure of the assemblies were measured and compared. RESULTS The mean age of the bodies was 66 years (+/-8). No significant difference was demonstrated between the groups in terms of residual motion and stiffness in both vertical and rotational displacement. The results showed a slight residual mobility in rotation of the hemipelvis. The SIFs presented greater, although non significant resistance to failure. No fixation, however, restituted stiffness comparable to a healthy pelvis. DISCUSSION The results of this study show that a Tile C.1.2-type injury to the pelvic ring can be treated as effectively with ISS or SIF when combined anterior and posterior fixations are performed. SIF therefore seems reliable and its continued use is justified. The long-term clinical outcomes should nevertheless be evaluated, notably on the younger population, more often affected by this type of injury.

The sagittal balance of the spine in children and adolescents with osteogenesis imperfecta

In severe forms of osteogenesis imperfecta, multiple compression fractures of the spine, as well as vertebral height shortening could be responsible for an increased thoracic kyphosis or a diminished lumbar lordosis. Theses progressive changes in sagittal shapes of the trunk could be responsible for a global sagittal trunk imbalance. We compare the parameters of sagittal spinopelvic balance in young patients with OI to those parameters in a control group of healthy volunteers. Eighteen patients with osteogenesis imperfecta were compared to a cohort of 300 healthy volunteers. A standing lateral radiograph of the spine was obtained in a standardized fashion. The sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, thoracic kyphosis, T1 and T9 sagittal offset were measured using a computer-assisted method. The variations and reciprocal correlations of all parameters in both groups according to each other were studied. Comparison of angular parameters between OI patients and control group showed an increased T1T12 kyphosis in OI patients. T1 and T9 sagittal offset was positive in OI patients and negative in control group. This statistically significant difference among sagittal offsets in both groups indicated that OI patients had a global sagittal balance of the trunk displaced anteriorly when compared to the normal population. Reciprocal correlations between angular parameters in OI patients showed a strong correlation between lumbar lordosis (L1L5 and L1S1) and sacral slope. The T9 sagittal offset was also strongly correlated with pelvic tilt. Pelvic incidence was correlated with L1S1 lordosis, T1 sagittal offset and pelvic tilt. In OI patients, the T1T12 thoracic kyphosis was statistically higher than in control group and was not correlated with other shape (LL) or pelvic (SS, PT or PI) parameters. Because isolated T1T12 kyphosis increase without T4T12 significant modification, we suggest that vertebral deformations worsen in OI patients at the upper part of thoracic spine. Further studies are needed to precise the exact location of most frequent vertebral deformities.

Oncogenous osteomalacia and myopericytoma of the thoracic spine: a case report.

Study Design. A case report. Objective. To illustrate a rare case of oncogenous osteomalacia caused by a spinal thoracic myopericytoma. Summary of Background Data. Osteomalacia related to a tumor is well known. The cause of the disorder is usually a highly vascularized, benign tumor of mesenchymal origin. Location of the tumor in the spine is very rare. Removal of the tumor is followed by resolution of osteomalacia. Methods. Diagnosis of oseomalacia was established on the presence of cardinal clinical, biologic, and radiologic features of osteomalacia. Localization of the tumor at T5 and T6 levels was obtained by magnetic resonance imaging. Surgical treatment consisted in a circumferential correction-fusion with hemivertebrectomy of T5 and T6 and tumor removal. Results. Tumor removal was rapidly followed by disappearance of the clinical symptoms of osteomalacia, and by correction of hypophosphatemia. At 2-years follow-up, no recurrence of the tumor was detectable on imaging studies—the correction fusion remained stable. Histologically, the tumor was classified as a myopericytoma. There was no relapse of the clinical features of osteomalacia. However, secondary recurrence of the biologic markers due to an incomplete tumor removal was disclosed. Conclusion. Removal of the tumor was followed by healing of the clinical features of osteomalacia, demonstrating the causal connection between the myopericytoma and the osteopathy.

[Superior mesenteric artery syndrome following correction of spinal deformity: case report and review of the literature].

Superior mesenteric artery syndrome is a rare complication which can develop after surgical correction of a spinal deformity. The syndrome is caused by an extrinsic compression on the third portion of the duodenum by the aorta posteriorly and the mesenteric artery anteriorly. We report here a case of aortomesenteric compression of the duodenum secondary to surgical correction of lower thoracic scoliosis in a 19-year-old female. The patient presented vomiting and intestinal obstruction ten days after spinal surgery. Treatment consisted in exclusive parenteral nutrition followed by careful surveillance and progressive reintroduction of oral food intake to avoid unnecessary surgery. Young thin subjects are predominantly exposed to this type of complication. The body mass index is a good indication to identify subjects at risk. Symptoms of upper gastrointestinal obstruction develop seven to ten days after surgery. Diagnosis is based on transit studies using a hydroluble contrast agent which reveals major gastric dilation and a clear interruption of the transit at the level of the third duodenum as well as retrograde peristaltism. Medical treatment should be undertaken first and is effective in the large majority of cases. Surgery may be proposed only in the event of failure. Recurrence is exceptional. Early diagnosis, delivery of clear information for the patient and family and multidisciplinary management are important points to consider for proper care for this complication which if neglected can become life-threatening.

Hydatid disease drug therapy primarily to reconstruction of a multilevel thoracolumbar vertebral lesion

We report, a very unusual case of multilevel vertebral hydatidosis adjacent to the thoracolumbar junction, without concomitant chord compression. Two months after initiating oral antiparasite treatment, the patient underwent resection of the lesion using a posterior approach, medullary decompression, and a T11-L3 instrumented arthrodesis. Arthrodesis via the anterior approach was performed at a later stage. In addition to its diagnostic value, this case raises renewed discussion about single-level lesions given their rarity: their indication for preoperative medullary angiography, their indication for circumferential surgery, the timing of medical treatment, and the strategy to implement for the residual lesions.

Assessing the rotation of the spinal cord in idiopathic scoliosis: a preliminary report of MRI feasibility

PurposeMagnetic resonance imaging (MRI) quantification of the rotation of the spinal cord in patients with thoracic idiopathic scoliosis could also be used to detect different spinal cord rotational patterns.MethodsTen patients with a thoracic or thoracolumbar scoliosis had axial T2-weighted MRI. The rotation of the spinal cord and vertebra were measured. The rotational data of the spinal cord and vertebra was compared to other collated data using non-parametric tests.ResultsThe vertebral tile was measured from 3° to 32° and the spinal cord tilt was measured from 3° to 39°. The spinal cord tilt was statistically correlated with the Cobb angle and the antero-posterior or and transverse diameter of the spinal cord.ConclusionWe showed that, even in case of moderate curve with very limited angular values and vertebral rotation, a significant spinal cord rotation occurred. However, our findings are very limited to discuss some hypothesis about scoliosis pathogeny or progression mechanism.

Influence de la hauteur discale sur le devenir d’une arthrodèse postérolaterale

PURPOSE OF THE STUDY Experimentally, posterolateral fusion only provides incomplete control of flexion-extension, rotation and lateral inclination forces. The stability deficit increases with increasing height of the anterior intervertebral space, which for some warrants the adjunction of an intersomatic arthrodesis in addition to the posterolateral graft. Few studies have been devoted to the impact of disc height on the outcome of posterolateral fusion. The purpose of this work was to investigate the spinal segment immobilized by the posterolateral fusion: height of the anterior intervertebral space, the clinical and radiographic impact of changes in disc height, and the short- and long-term impact of disc height measured preoperatively on clinical and radiographic outcome. MATERIALS AND METHODS In order to obtain a homogeneous group of patients, the series was limited to patients undergoing posterolateral arthrodesis for degenerative spondylolisthesis, in combination with radicular release. This was a retrospective analysis of a consecutive series of 66 patients with mean 52 months follow-up (range 3-63 months). A dedicated self-administered questionnaire was used to collect data on pre- and postoperative function, the SF-36 quality of life score, and patient satisfaction. Pre- and postoperative (early, one year, last follow-up) radiographic data were recorded: olisthesic level, disc height, intervertebral angle, intervertebral mobility (angular, anteroposterior), and global measures of sagittal balance (thoracic kyphosis, lumbar lordosis, T9 sagittal tilt, pelvic version, pelvic incidence, sacral slope). SpineView was used for all measures. Univariate analysis searched for correlations between variation in disc height and early postoperative function and quality of fusion at last follow-up. Multivariate analysis was applied to the following preoperative parameters: intervertebral angle, disc height, intervertebral mobility, sagittal balance parameters, use of osteosynthesis or not. RESULTS At the olisthesic level, there was a 30% mean decrease in disc height and intervertebral angle. These variations were not correlated with functional outcome or quality of fusion observed at last follow-up. Disc height preoperatively did not affect these variations. The only factor correlated with decreased disc height was T9 sagittal tilt: disc height decreased more when T9 sagittal tilt approached 0 degrees . DISCUSSION In this very restricted context (retrospective study, short arthrodesis for degenerative spondylolisthesis), we were unable to find any evidence supporting the notion that high disc height is an argument which should favor complementary intersomatic arthrodesis in combination with posterolateral fusion. Analysis of the spinal balance in the sagittal plane would probably allow a more pertinent assessment of the specific needs of individual patients.