The External Fixator

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.