by Robert W. Gaines J Bone Joint Surg Am Volume 82(10):

The Use of Pedicle-Screw Internal Fixation for the Operative Treatment of Spinal Disorders*

by Robert W. Gaines

J Bone Joint Surg AmVolume 82(10):1458-1458

October 1, 2000

©2000 by The Journal of Bone and Joint Surgery, Inc.

The Roy-Camille plate137,138 (left) and the Steffee variable-screw-placement (VSP) plate152 (right).

Robert W. Gaines, Jr. J Bone Joint Surg Am 2000;82:1458


Drawings clearly illustrating the benefits of screw triangulation to improve pullout strength, particularly when the screws are cross-connected to one another9.



The 4R-4bar linkage collapse associated with parallel pedicle screws (left) can be resisted only by load-sharing through the fracture site (right)23.



The "JIKEI Index" easily relates bone-mineral density and pedicle-screw pullout strength with this simple x-ray-based scheme.



Model developed by the American Society for Testing and Materials for construct or subconstruct testing.



Bar graphs showing the changes in pullout force (A) and bending stiffness (B) when screws with five and six-millimeter major diameters are compared.



Bar graphs showing differences in resistance to cyclic loading34.



Photographs illustrating the Funnel Technique.



Graph showing improved screw-bending stiffness due to the addition of polymethylmethacrylate (PMMA) and polypropylene glycol-fumarate (PPF).



The load-sharing classification permits quantification of comminution of spinal fracture sites so that the load-sharing capability of the injured vertebral body itself, along with the implant

system, can be determined.



Figs. 11-A through 11-E: A patient with severe thoracic scoliosis who had excellent correction of both the primary curve and the tilt angle with use of pedicle screws for the caudal platform.



Posteroanterior radiographs demonstrating an 88-degree curve with the patient standing and a 53-degree right thoracic curve with the patient stretching.



Posteroanterior radiograph made ten months postoperatively, demonstrating correction and restored compensation.



Postoperative posteroanterior and forward-bending posteroanterior photographs, demonstrating good balance and mobility in the lumbar spine.



Preoperative and postoperative standing lateral radiographs demonstrating correction of the midthoracic kyphotic deformity.



Intermediate-grade spondylolisthesis and/or degenerative spondylolisthesis can now be well treated with reduction with the posterior approach only, with use of interbody fusion with cages

and pedicle screws.



Reconstruction of spinal fractures is much more secure with pedicle screws.



Figs. 14-A through 14-D: Spinal osteotomy has become a much more predictable surgical technique since the adoption of pedicle screws, which provide more secure fixation than any

previous technique.Fig. 14-A: The site of the corrective osteotomy should be at...



This patient had a post-fracture flatback deformity after Harrington instrumentation, with fixed deformity in the lumbar spine.



Close-up preoperative and postoperative lateral radiographs.



Preoperative and postoperative lateral photographs showing dramatic realignment.



In tumor reconstructions, pedicle screws permit segmental resection, realignment, and reconstruction over shorter segments than was possible before their introduction.



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by Robert W. Gaines J Bone Joint Surg Am Volume 82(10):