Current methods of dorsal spine fusion with pedical screws and presentation of a new method for treatment of fractures and low back instability.

A new instrumentation system, the H-frame system, has been developed for dorsal fusion in scoliosis, spinal fractures and degenerative low back problems. The basis is a prelinked slotted H-frame with two rods of 6-mm diameter with 5-cm threaded ends. There are 4 different lengths, solid in the middle and threaded at the ends. Connection with hooks and/or pedical screws is easy and stable. A slotted system using special conical nuts to grasp these hooks or screws tightly prevents loosening. For low back fusion in degenerative disease the slightly lordotic H-frame is connected to 4 screws. If needed, a sublaminar Luque wire may be added in between. Correction in lordosis with distraction or compression is possible. The fixation is very rigid in all directions with a minimum of implant material. For thoracolumbar fresh fractures 2 pedical screws are placed above and 2 screws below the fracture area, and an H-frame is inserted with one end fixed below and one end above the opposite side of the other rod. Because of the rotary section in the H-frame, the apparatus may be repositioned simply by pushing the frame with the two other screws under control of the H-frame cross-link connection. Distraction and correction of kyphosis is achieved with this simple movement at the same time. The total stable fixation needs no after-treatment. The method may also be used for scoliosis with a combination of hooks, screws and wires. Experience is still very limited. The apparatus has been used in the lumbar spine in more than 10 cases with over 6 months follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)