Biomedical subjects
Publications and source records attributed to A Chevrot.
Wrist imaging still relies first on plain X-Ray films, MRI allows excellent appreciation of the sculture of bones, ligaments, tendons and even nerves. C.T. is essentially useful in traumatology, while Wrist arthrography can be useful for detection of small ligament lesions.
A wrong patient's position on the CT scan table may lead to mistakes in the measurement of femoral neck anteversion. We present an experimental demonstration using a wood manufactured femur model. If the slices are performed with flexion of the thigh, the measurement is lower than the true value. Thus, to check the measurement on the picture of added slices, it is necessary to have a superimposition of the pictures of the upper part and the lower part of the femur. Otherwise, the measure is wrong and the mistake depends of the direction of the shifting: --if the lower part of the femur is higher, the anteversion measure is lower than expected. --if the lower part of the femur is lower, the anteversion measure is higher.
In summary, septic arthritis of a lumbar facet joint has been rarely discussed in the literature [1, 4]. In this case report the histological and bacteriological diagnosis was established by percutaneous needle biopsy guided by fluoroscopy and the response to treatment was confirmed by CT scans.
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Despite new imaging modalities such as MRI, the discography remains useful, particularly as the first step of chemonucleolysis. The anulography corresponds to a technical error due to the wrong position of the needle during the procedure. We have noticed 32 anulographies on 1226 discographies done in our department, between 1985 and 1989. The anulography exhibits a typical pattern that must be diagnosed; if not, that can lead to a diagnosis mistake or a wrong therapeutic attitude. The needle of discography must then be repositioned.
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The authors report 8 cases of sciatica secondary to a posterior articular cyst. They emphasize the clinical manifestations permitting to suspect this etiology of root compression, which, until now, was rather unusual. Computerized axial tomography makes the diagnosis possible along with posterior arthrography. This arthrography represents the first stage of the medical treatment by posterior joint infiltration of a steroid derivative. In 60 p. cent of the cases, a definite and persisting improvement permits to avoid a surgical procedure.
CT scan sagittal reconstructions allow accurate angular measurements of the extent of the avascular necrosis of the hip, that is necessary to consider in view of an osteotomy of rotation Sugioka type. This method is performed on a supine patient with internal rotated and extended lower limbs, using 5 mm slices from the acetabular roof to the distal part of the femoral neck. A sagittal reconstruction through the middle of the femoral head is then performed, owing a direct measurement of the extent of the necrosis and of the theoretical rotation to be used in order to keep it out of the carrying zone. Twenty hips have been studied by this method which can be used post-operatively with satisfying results. It replaces the more radiating conventional tomographies. The protonic image of MRI will perhaps substitute it, but CT gives a "calcium" image probably more accurate for the analysis of the carrying zones.
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To develop criteria to distinguish among pyogenic infection, nonpyogenic infection, and neoplastic processes in the spine by means of computed tomography (CT), the authors retrospectively analyzed 17 cases of pyogenic infection (20 sites), 40 cases of neoplastic disease (56 sites), and five cases of granulomatous infection (eight sites). Reliable criteria for pyogenic infection were complete prevertebral soft-tissue involvement, diffuse osteolytic destruction, gas within both bone and soft tissue, and a process centering on an intervertebral disk. Neoplastic disease was characterized by posterior element involvement, partial or absent prevertebral soft-tissue swelling, and osteoblastic alterations. In a limited number of cases, nonpyogenic infection was characterized by focal lytic bone involvement and marginal sclerosis. Blinded testing of these criteria indicated potential for improved diagnostic accuracy in clinical practice.
The retrospective study of the first 67 patients treated by chemonucleolysis, since December 1980, shows a good overall result, in 69 p. cent of the cases (40 patients) and a failure in 31 p. cent of the cases (18 patients), with a 42 months follow-up. The radiculalgia is cured or quite improved in one month in 90 p. cent of the cases and in 2 years in 88 p. cent. Lumbalgia is absent or moderate after 1 month in 58 p. cent of the cases and after 2 years in 81 p. cent. It persists, most of the time, in women, and this is statistically significant. 15 immediate failures and 3 recurrent sciaticas at the same level are noticed after a 22 months free interval. The possibility of severe complications requires a perfect technique and well-defined indications. The study confirms the good results of nucleolysis with a 42 months follow-up.
Posterior pre-marginal disk hernia, a rare lesion, was diagnosed in six young adults with lumbago. Lateral lumbar spine radiographic images showed an unusual appearance, combining a posterior marginal defect of a vertebral corner and a small bony spicule projecting into lumbar canal. A literature review revealed 27 similar cases, mostly in adolescents. These vertebral disk anomalies are considered by some authors to be fractures of the posterior margin border. A more plausible hypothesis is a pre-marginal hernia, because of lack of a history of injury, the radiologic appearance comparable with that of sequelae of Scheuermann's disease, and the frequent association of these lesions with a spinal growth dystrophy.
Condensing pediculolaminar hypertrophy of mechanical origin is known as "Dahu's sign". Dahu's sign corresponds to hypertrophy of the vertebral hemi-arch found by CT scan and leads to suspicion of controlateral lysis of the isthmus. It is the CT scan equivalent of vertebral "anisocorism" by conventional radiology.
In the context of a particular case report, the authors recall that calcified discs may be responsible for root pain, hyperalgic sciatica or lumbago. In the present case, the pain responded to intra-discal injection of long-acting corticosteroids. The authors compare this case to 10 other personal cases and 16 cases reported in the literature.
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