The External Fixator

Professor B.G. WEBER has once again and in a very timely fashion produced a superb book on an orthopaedic subject of great importance. "The Extemal Fixator" is the most comprehensive text on the subject in orthopaedic literature to date. Professor WEBER thoroughly discusses extemal fixation with c1arity, organization, profuse illustrations and roentgenograms. Professor WEBER acknowledges that the use of extemal fixation in orthopaedic surgery is not newand traces its history over the years. He points out c1early the fact that though at various times the "method" has experienced periods of disrepute, modem sophistication, improved technology and a better understanding of its philosophy have given the system a newand perhaps permanent place in the armamentarium of the orthopaedic surgeon. All methods of treatment have critics as well as supporters, and not infrequently the strongest criticisms are the result of poor understanding of the philosophy proposed and its proper implementation. Professor WEBER, in his carefully detailed and well illustrated book, has made it abundantly c1ear that the use of extemal fixators in the treatment of fractures must be c1early understood by the orthopaedic surgeon in order to obtain satisfactory clinical results. His discussion of its philosophy, pathomechanics and technology are most comprehensive and leave "no stone untumed" and because of this the book represents a most comprehensive text on the subject.

Preamble.- The ASIF Threaded External Fixator in General Orthopaedic and Trauma Surgery of the Extremities.- A General Part.- 1 Introduction.- 2 The History of External Fixation.- 3 Bone Healing in the Presence of an External Fixator.- 3.1 Healing of a Diaphyseal Fracture.- 3.1.1 Primary Healing of the Cortex.- 3.1.2 Secondary Healing of the Cortex.- 3.1.3 Nonunion.- 3.1.3.1 Pathogenesis of Vascular Nonunion.- 3.1.3.2 Pathogenesis of Avascular Nonunion.- 3.2 Healing of Cancellous Bone.- 3.2.1 Primary Healing of Cancellous Bone.- 3.2.2 Secondary Healing of Cancellous Bone.- 3.2.3 Nonunion of Cancellous Bone.- 3.2.3.1 Pathogenesis of Vascular Nonunion.- 3.2.3.2 Pathogenesis of Avascular Nonunion.- 3.3 Healing of Nonunions.- 3.3.1 Healing of a Vascular Nonunion.- 3.3.2 Healing of an Avascular Nonunion.- 3.3.3 Healing of a Nonunion with Bone Loss.- 4 Goals of Treatment with the External Fixator.- 4.1 Lengthening Frame.- 4.2 Neutralization Frame.- 4.3 Compression Frame.- 4.4 Soft-Tissue Frame.- B On the Biomechanics of External Fixation.- 1 Intrinsic Stability of the External Fixator.- 2 The External Fixator and Bone as a Composite System.- 2.1 External Fixation without Interfragmental Contact.- 2.2 External Fixation with Interfragmental Contact.- 2.3 External Fixation with Interfragmental Compression.- 2.4 Biomechanics and Selection of the Frame.- 3 Stress Transfer with the External Fixator.- 3.1 Stress Transfer with the Neutralization and Lengthening Frame.- 3.2 Stress Transfer in the Presence of Bone Contact.- 3.2.1 Stress Transfer with a Bilateral Compression Frame.- 3.2.2 Stress Transfer with a Unilateral Compression Frame.- 3.2.2.1 “Prebending” of the Rod.- 3.2.2.2 “Prebending” of the Bone.- 3.2.2.3 Axial Compression with a “Spreading Rod”.- 4 Means of Augmenting the Stability of the External Fixator.- 4.1 Increasing the Number of Pins or Screws.- 4.2 Placement of the Pins and Screws.- 4.3 Increasing the Number of Rods.- 4.4 The Double-Frame Configuration.- 4.5 The Biplanar Frame.- 5 Improving the Anchorage of Pins and Screws in Bone.- 6 Restoring the Compressive Strength of Bone in the Absence of Interfragmental Contact.- 6.1 Restoring Bone Contact by Shortening.- 6.2 Restoring Bone Contact by Interposing a Pressure-Resistant Bone Graft.- 6.3 Restoring Bone Contact by Adjunctive Internal Fixation.- 6.3.1 Lag Screw plus External Fixation.- 6.3.2 Antiglide Plate plus External Fixation.- 6.4 Restoring Bone Contact by Cancellous Bone Grafting.- 6.5 Restoring Bone Contact by Transverse Compression.- 6.6 Restoring Bone Contact by Fragment Manipulation.- 7 Sagittal or “Intermediate” Screw Placement in Unilateral External Fixation of the Tibia.- 8 Summary of the Biomechanics of External Fixation.- 8.1 The External Fixator and Bone.- 8.2 Unilateral or Bilateral Frame.- 8.3 Elasticity of the External Fixator.- C The Threaded External Fixator. Instrumentation.- 1 Introduction.- 1.1 Requirements of the External Fixator.- 1.2 The External Fixator of the ASIF.- 2 The Elements of the Threaded External Fixator.- 2.1 Steinmann Pins.- 2.2 Schanz Screws.- 2.3 The 4.5-mm and 3.5-mm Cortex Screws.- 2.4 Drill Bits, Drill Sleeves and Taps.- 2.5 Clamps for Steinmann Pins, Schanz Screws, 4.5-mm and 3.5-mm Cortex Screws.- 2.6 Threaded Rods.- 2.7 Nuts.- 2.8 Slider Bar.- 2.9 Additional Instruments and Implants.- 2.10 Special Instruments.- 3 The Threaded Minifixator.- D Operative Technique for the Threaded External Fixator.- 1 The Special Characteristics of the Threaded External Fixator.- 2 Errors of Pin and Screw Insertion.- 2.1 Technique for Steinmann Pins.- 2.2 Technique for Schanz Screws.- 2.3 Technique for Cortex Screws.- 3 Reduction.- 3.1 Concept.- 3.2 Technique.- 4 The Application of a Bilateral Frame.- 4.1 Pin Placement.- 4.2 Pin Insertion.- 4.3 Assembling the Frame.- 4.4 Reinforcing the Frame.- 4.5 Finishing the Frame.- 5 The Application of a Unilateral Frame.- 5.1 Placement of the Schanz Screws.- 5.2 Screw Insertion.- 5.3 Assembling the Unilateral Frame.- 5.4 Reinforcing the Frame.- 5.5 Finishing the Frame.- E Techniques for Reinforcing the External Fixator.- 1 Increasing the Number of Rods.- 2 Mounting Additional Rods in a Perpendicular Configuration.- 3 Stability of the Unilateral Frame.- 4 Restoring Bone Contact.- 5 Stability Enhancement and Frame Design.- F Situations Requiring a Special Operative Technique.- 1 Stabilization of Short Fragments.- 2 Diagonal Bracing Rod.- 3 Adding Single Clamps to the Frame, and Transverse Compression.- G Axial Corrections.- 1 Axial Corrections in the Bilateral Frame.- 2 Axial Corrections in the Unilateral Frame.- 3 Axial Corrections with the Aid of an External Frame.- H Local Care Following Frame Application.- 1 Postoperative Care.- 2 Further Supervision.- I Duration of External Fixation, and Removal of the External Fixator.- 1 General Duration of External Fixation.- 2 Early Removal of Individual Pins or Screws.- 3 Staged Removal of Combined Frames.- 4 Removal of the External Fixator.- 5 “Dynamization” of External Fixator Frames.- K Instrumentation Used with the Threaded External Fixator.- 1 General.- 2 Threaded External Fixator Sets.- L The Threaded External Fixator in Adults. Clinical Examples.- 1 Introduction.- 2 Humerus.- 3 Elbow.- 4 Wrist.- 5 Pelvis.- 6 Femur.- 7 Knee.- 8 Tibia.- 9 Ankle.- 10 Soft Tissues.- M The Threaded External Fixator in Children and Adolescents.- 1 Introduction.- 2 The External Fixator for Severe Open Fractures in Children, Infected Fractures and Infected Nonunions.- 3 Corrective Osteotomies of the Proximal Femur in Small Children.- 3.1 Instrumentation and Technique.- 3.2 The Technique Practiced at our Center.- 3.3 Indications and Examples.- 4 Lengthening Osteotomies in Children and Adolescents.- 4.1 Introduction.- 4.2 Lengthening Osteotomy of the Humerus.- 4.3 Lengthening Osteotomy of the Femur.- 4.4 Lengthening of the Tibia.- 5 Corrective Osteotomy for Staged Limb Lengthening.- 5.1 Staged Supracondylar Lengthening of the Femur.- 5.2 Corrective Osteotomy of the Proximal Tibia.- 5.3 Supramalleolar Corrective Osteotomy of the Tibia.- 6 Special Problems.- N Concluding Remarks.- External Spinal Skeletal Fixation.- 1 Introduction.- 2 Classification and Prognosis of Spinal Injuries and Their Relevance to Stabilization.- 2.1 Wedge-Compression Fracture.- 2.2 Stable Burst Fracture or Incomplete Burst Fracture.- 2.3 Unstable Burst Fracture or Complete Burst Fracture.- 2.4 Chance Fracture.- 2.5 Flexion-Distraction Injury.- 2.6 Translational Injuries.- 2.7 Remarks on Classification.- 2.8 Classification and Mode of Treatment.- 2.9 Degree of Stability.- 2.10 Type of Instability and Prognosis.- 2.11 Prognostic Significance of Angular Deformities.- 3 The ESSF Device and Instrument Set.- 4 Biomechanics of the ESSF Device.- 4.1 Open or Percutaneous Application of the ESSF Device.- 4.2 The Importance of Prestressing.- 4.3 Use of the ESSF Device in the Neutral Mode.- 4.4 Use of the ESSF Device in Distraction.- 4.4.1 Percutaneous Application.- 4.4.2 Open Application (Technique I–III).- 4.5 Use of the ESSF Device in Compression.- 4.6 Stabilization of Fractures of the Fifth Lumbar Vertebra.- 4.7 Translaminar Screw Fixation of Facet Joints.- 4.8 Coupled ESSF Assemblies.- 4.8.1 The Straight Coupled Assembly.- 4.8.2 The Angled Coupled Assembly.- 4.8.3 Application and Prestressing of Coupled Assemblies.- 5 Experimental Investigations.- 6 Indications for the ESSF Device.- 6.1 Trauma.- 6.2 Other Indications.- 7 Timing of Surgery.- 8 Operative Technique: Trauma.- 8.1 Open Technique.- 8.1.1 Operating Table, Closed Reduction, Positioning.- 8.1.2 Approach.- 8.1.3 Intraoperative Reduction.- 8.1.4 Insertion of the Schanz Screws.- 8.1.5 Instrumental Reduction, Distraction-Decompression.- 8.1.6 Intraoperative Myelography.- 8.1.7 Laminectomy, Open Decompression, Repair of Dural Lacerations.- 8.1.8 Stabilization of Posterior Elements, Translaminar Screw Fixation, H-Graft, Tension Band Wiring.- 8.1.9 Definitive Insertion of the Schanz Screws, Cancellous Bone Grafting, Wound Closure.- 8.1.10 Assembly and Prestressing of the ESSF Device.- 8.1.11 Open Technique with Cancellous Grafting of the Vertebral Body, Posterior Interbody Fusion.- 8.2 Percutaneous Application of the Fixation Device.- 8.3 Repositioning the Fixation Device, Combined Open and Percutaneous Application.- 8.3.1 Repositioning the Device.- 8.3.2 Combined Application.- 9 Operative Technique: Spondylitis.- 9.1 Two-Stage Procedure with Direct Focal Treatment.- 9.2 Semidirect Treatment.- 9.3 Indirect Treatment.- 10 Postoperative Care and Postoperative Course.- 10.1 General Remarks.- 10.2 Postoperative Management of Fractures.- 10.3 Postoperative Management of Spondylitis.- 11 Clinical Examples.- 11.1 Trauma.- 11.1.1 Open Procedure, Technique I.- 11.1.2 Open Procedure, Technique II.- 11.1.3 Open Procedure, Technique III.- 11.1.4 Stabilization of the 5th Lumbar Vertebra with the ESSF Device.- 11.1.5 Open or Open-Percutaneous Stabilization with the Simple ESSF Device Over More than Two Motion Segments.- 11.1.6 Stabilization of an Interbody Fusion with the ESSF Device.- 11.1.7 Percutaneous Application of the Simple ESSF Device or Coupled Assembly.- 11.1.8 Example of a Complication: Collapse of the Vertebral Body after Removal of the ESSF Device.- 11.2 Spondylitis.- 11.2.1 Two-Stage Procedure with Open Surgical Treatment.- 11.2.2 Exception: Single-Stage Procedure with Open Surgical Treatment.- 11.2.3 Indirect Treatment of Spondylitis with Percutaneous Application of the ESSF Device.- 12 Results of Treatment.- 12.1 Fractures.- 12.1.1 Injuries.- 12.1.2 Treatment.- 12.1.3 Results of Treatment.- 12.1.4 Complications.- 12.2 Spondylitis.- 12.2.1 Causative Organisms, Localization, Findings.- 12.2.2 Treatment.- 12.2.3 Results of Treatment.- 12.2.4 Complications.- 12.3 Other Indications.- 13 Discussion of the Method of Treatment.- 14 Remarks.- References.