[Fractures of the ischium after laminoarthrectomy. Retrospective study of a series of 31 patients]. / Les fractues d'isthme après laminoarthrectomie. Etude rétrospective d'une série de 31 patients.

PURPOSE OF THE STUDY: Pars interarticularis fracture is one possible source of pain after laminoarthrectomy. The purposes of this study were: to describe the pars defect, to determine its causes and to analyse its consequences on the functional final result. MATERIAL AND METHOD: 31 patients operated for disc herniation or degenerative lumbar stenosis were retrospectively studied. Clinical symptoms were evaluated before and 3 months after initial surgery, at the time of postlaminectomy radiological examination and at last follow-up according to Beaujon rating scale. Radiological evaluation included: description of the pars defect on plain radiographs and CT imaging, calculation of the amount of bone just above the inferior articular process that was resected, analysis of the postoperative stability of the spine both on static and dynamic radiographs. Any remaining disc herniation or stenosis were also noted. RESULTS: 39 pars interarticularis fractures were disclosed. These fractures were identified as a linear luency on plain radiographs or on reformed CT imaging view. Asymmetric widening of the facet joint space just below the pars defect was easier to observe and was present in 66 per cent of the cases on plain radiographs and in 79 per cent on CT imaging. After initial surgery 12 slipping appeared. In all of these cases pars fracture was bilateral at the same level or associated to a complete unilateral facetectomy at the same level. The amount of bone resected just above the inferior facet process was 66 per cent in average, range from 45 to 84 per cent. All the patients complained for low back pain and/or leg pain. In 62 per cent of cases symptoms occurred within one year after surgery, at an average onset of 7.6 months postlaminectomy. 27 patients were reported Revision surgery was in all cases a posterolateral fusion with or without instrumentation; new decompression was performed in 15 cases. At last follow-up, according to our classification, results were very good in 9 cases, good in 15 cases and fair in the remaining 3 cases. Improvement rate obtained after the initial surgery was 75 per cent in average, it was 59 per cent after revision surgery, difference was statistically significant. CONCLUSION: Pars interarticularis fractures may be a source of postlaminectomy pain. They appear to be caused primarily by an excessive resection (more than one half) of the bone immediately superior to the inferior articular process at the level of the laminectomy. These results suggest that caution in resection of this bone or additional posterolateral fusion in case of large resection of pars interarticularis, can avoid the problem. Asymmetric widening of the joint space just below the defect seems to be the key to this diagnosis in the postoperative lumbar laminectomy patient with persistent or recurrent pain.

Chemonucleolysis: correlation of results with the size of the herniation and the dimensions of the spinal canal.

The aim of this study was to determine whether the results of chemonucleolysis are related to the size of the disc herniation and to the dimensions of the spinal canal. Short and long-term results (average follow-up 4 and a half years) of 148 patients were evaluated. Measurements made with a divider included the size of the disc herniation related to the sagittal diameter of the spinal canal at the discal level and the transverse interligamentous diameter at the level of the facet joints. The morphology of the lateral recess was also assessed. Measurements were initially made by five observers and were repeated eight times and on eight computed tomography (CT) scans in order to assess intra- and interobserver variability. Measurements of the entire series were then made by the two observers demonstrating a good intra- and interobserver reproducibility. Of the 148 patients 74% had an overall successful result. No significant difference was disclosed when comparing the various parameters of the clinical results with the size of the herniation. Similarly, a lack of correlation was also found between the clinical results and the dimensions of the spinal canal and of the lateral recess. In this series, the results were not significantly influenced by the size of the herniation or the morphology of the spinal canal.

Left tuberothalamic artery territory infarction: neuropsychological and MRI features.

We examined a 29-year-old woman who had language disturbances and memory impairment after a left thalamic infarction. MRI showed injury that was limited to the tuberothalamic artery territory. Beside reduced voice volume and verbal memory trouble, she presented with aspontaneity, loss of psychic self-activation and affective drive. Considering thalamic lesions, this loss of psychic self-activation or 'athymhormie' was found in a left thalamic infarct and could not be considered as an exclusive characteristic of bithalamic infarctions. The disappearance of the neurobehavioral disturbances within 15 days after the onset of the troubles was associated with the decreasing of the mass lesion found by MRI.

Diagnosis of abdominal venous thrombosis by means of spin-echo and gradient-echo MR imaging: analysis with receiver operating characteristic curves.

The authors compared the accuracy of spin-echo (SE) and gradient-echo (GRE) magnetic resonance images in diagnosis of abdominal venous thrombosis. Images of 292 abdominal veins in 72 patients were reviewed in a blinded manner by three radiologists, with seven levels of confidence for diagnosis. Corroborative studies proved thrombosis (n = 95) and vessel patency (n = 197). Receiver operating characteristic (ROC) curves were constructed for SE images alone, GRE images alone, and SE and GRE images combined. At specificities of 90% and 95%, thrombi were identified with sensitivities, respectively, of 76% and 63% with SE images, 74% and 58% with GRE images, and 88% and 82% with combined SE and GRE images. The area under the ROC curve for SE and GRE images combined (0.958 +/- 0.011 [standard deviation]) was significantly larger (P less than .001) than that for SE images alone (0.913 +/- 0.018) and GRE images alone (0.921 +/- 0.016). It is concluded that combination of SE and GRE images significantly increases the accuracy of diagnosis of abdominal venous thrombosis.

[Infratemporal extension of tumors of the skull base]. / Extension à la fosse infra-temporale des tumeurs de la base du crâne.

The tumors of the middle and posterior portion of the skull base may extend extracranially. The spread of the tumors towards the infratemporal fossa is rare. Among 23 skull base tumors with extracranial extension which were diagnosed during the last 5 years, only two middle ear epidermoid carcinomas extended into the infratemporal fossa. Subtotal surgical removal of tumors was obtained in both cases through a subtotal petrectomy with an ultrasonic aspiration of the extracranial extension followed by transcutaneous irradiation. One case is followed free of disease 2 years and a half after the beginning of the treatment. The spread of the tumor into the infratemporal fossa might not be of poor prognosis.