Imaging of intervertebral disc prostheses

Disc arthroplasty is the replacement of a painful pathological intervertebral disc by a prosthesis, which, unlike spinal fixation, has the advantage of retaining vertebral mobility in the segment concerned. The success of the procedure is dictated by the indication. The radiologist must look for radiographic arguments indicating or contraindicating fitting an implant, and particularly for the presence of facet arthritis which will prompt the surgeon to choose an arthrodesis. Moreover, radiological information plays a major part in preparing for a surgical procedure, as far as access to the disc via the anterior approach is concerned and assessment by CT angiography of the risk of vascular complications. After insertion, radiological monitoring using dynamic X-ray images checks that the implant is correctly positioned and that mobility is restored. In the long term, it can detect complications related to the prosthesis and premature wear to other points of support such as adjacent discs and the facet joints.

Prothèse totale de hanche bilatérale en une session opératoire

PURPOSE OF THE STUDY

We conducted a prospective study of patients undergoing simultaneous bilateral total hip arthroplasty (THA) in order to assess perioperative complications. A review of the literature revealed the pertinence of surgical management of patients with invalidating bilateral degenerative hip disease using a single-stage procedure.

MATERIAL AND METHODS

Ten patients, four females and six males, mean age 57.8 years (range 33-71 year) were included in the study. The ASA classification was 1 for nine patients and 2 for one. The procedure was performed in the lateral reclining position using a posterolateral approach. Mean operative time was 212 minutes (range 165-270min) and mean blood loss as assessed by serum hemoglobin level was 9 mmol/l preoperatively and 5.93 mmol/l postoperatively. Three patients required transfusion. Mean hospital stay was 11 days (range 7-13 d). Leg length discrepancy improved from an average 4 mm preoperatively to 0.5 mm postoperatively.

RESULTS

One patient developed a sacral pressure sore which resolved in 21 days. One patient developed a wound infection (Pseudomonas aeruginosa) which resolved with local treatment. No other complication (death, pulmonary embolism, dislocation, deep infection, stiffness, heterotopic ossification) was observed 17.6 at 15 months of follow-up. There were no revision procedures. The Postel-Merle-d'Aubigné score improved from 9.6 preoperatively to 15 at mean follow-up (range 10-24 months).

DISCUSSION

Bilateral implantation of THAs in a single-stage procedure is indicated for chronic invalidating bilateral degenerative disease. About 0.5% to 3% of hip replacement procedures concern simultaneous bilateral implantations. The complication rate is no higher than after sequential surgery or even after single THA procedures, including the risk of pulmonary embolism. The cost of the procedure and the mean hospital stay are reduced compared with two operations. Rehabilitation is facilitated. The operative time is however longer and the risk of bleeding is increased but can be compensated for preoperatively and minimized intra- and postoperatively. This attractive strategy is not currently sufficiently reimbursed by the current conditions of the French health care insurance system.