Erik B. Riska

Posterior spinal fusion using internal fixation with the Daab plate

The results of posterior spinal fusion, supplemented by internal fixation with the Daab plate in 43 patients, are presented. The Daab plate is a quadruped implant placed longitudinally in the coronal plane and fixed by simply pinching it around the spinous processes. The cause of the instability necessitating fusion was acute trauma in eight patients, late posttraumatic condition in 11, pure degenerative process in seven and spondylolisthesis in nine patients. In addition, there were solitary cases of tuberculous spondylitis, pyogenic spondylitis and metastatic destruction of the vertebral body. The fusion site was cervical in three, thoracic in eight, thoracolumbar in 12 and lumbar or lumbosacral in 20 cases. The mean follow-up time was 19 months. The consolidation of the fused area could, apart from radiographs, ultimately be evaluated at removal of the implant in 39 patients. The fusion was successful in 37 patients. Compared with previous reports, this result must be considered satisfactory when the severity of the cases in this series is noted. Internal fixation in connection with posterior fusion is needed only exceptionally, but in complicated cases the Daab plate seems to afford a simple method of securing the position of the segments for the first postoperative months.

Anterolateral decompression for neural involvement in thoracolumbar fractures. A review of 78 cases

Of a total of 905 patients with fracture or fracture-dislocation of the thoracolumbar spine admitted from 1969 to 1982, a neurological deficit was present in 334 (37%). All unstable injuries were initially treated by reduction and posterior fusion. In 79 of these patients, an anterolateral decompression was undertaken later because of persistent neurological deficit and radiographic demonstration of encroachment on the spinal canal. One patient died of pulmonary embolism; 78 were reviewed after a mean period of four years. Of these 78 patients 18 made a complete neurological recovery while 53 appeared to have benefited from the procedure; 25 remained unchanged. The best results were obtained in burst fractures at thoracolumbar and lumbar levels when a solitary detached fragment of a vertebral body had been displaced into the spinal canal. These results indicate that anterolateral decompression of the spinal canal should be considered, after careful evaluation, for certain injuries of the spine in which there is severe neural involvement.

Treatment of para-articular ossification after total hip replacement by excision and use of free fat transplants.

Six patients with para-articular ossification after total hip replacement were treated by excision and free fat tissue transplantation. The results of treatment were good and at the follow-up examinations, 2 to 8 years after the operation, a good range of movement of the hip joint was noted in all cases. It was apparent that the free fat transplant had prevented the recurrence of the para-articular ossification.

Recurrence of deformity after removal of Harrington's fixation of spine fracture: Seventy-six cases followed for 2 years

The radiographic result was assessed in 76 patients with acute unstable fractures of the thoracic or lumbar spine admitted during the years 1977-1984, and who were managed by early reduction and stabilization using Harrington distraction rods and a three-segmental posterolateral fusion. The radiographs were analyzed for anterior and posterior heights plus sagittal and frontal widths of the fractured vertebral body and the angles of kyphosis and scoliosis of the spine. All the measurements were made at admission, immediately postoperatively, and at the latest follow-up at least 3 months after removal of the rods, which was done as a routine procedure 6-12 months after the accident. The mean follow-up was 29 months. The posterior height and sagittal width of the vertebral bodies were best restored, whereas the initially well-reduced anterior height and the angle of kyphosis often had returned to values close to those seen on admission. The best anatomic restoration was obtained in rotation-dislocation injuries of the thoracic and thoracolumbar spine, and was poorest in burst fractures of the lumbar spine.

Replacement of the femoral head by ceramic endoprosthesis. An experimental study on rabbits.

In 31 rabbits the femoral head was replaced by a ceramic endoprosthesis. For 11 of the experimental animals the endoprostheses were made by the Arabia China Factory in Helsinki, and for 20 by Staatliche Porzellan Manufaktur in Berlin. The operation was performed under fully sterile conditions and the follow-up time was between 6 and 34 weeks. The hip joint was examined clinically, roentgenologically, macroscopically and histologically. The bending tolerance of the ceramic endoprosthesis was not adequate. Mechanical loosening of the proximal part of the prosthesis occurred in 68 per cent and was combined with fracture of the prosthetic stem. This created a pseudarthrosis-like reaction in the acetabular area and limited the movement of the hip joint. The distal fragment of the stem was always surrounded by a thin layer of dense bone. In the nonfractured cases (32 per cent), however, the reaction was only moderate and the movement of the hip joint was well preserved. The tissue reactions to the ceramic material were slight, but the great number of secondary reactions following stem fractures make the use of the ceramic endoprosthesis questionable in experiments with rabbits.