A Specialized Cervical Corpectomy Plate

Fault Tree Analysis

23 April 2008

Patient Hazards

Physical Failure

A

Design/Labeling Failure

B

A

Screw Problems

Plate Problems

Screw Failure

Screw

Translation

Screw Motion

C ED

Screw Hole Sizing

Plate Failure

Plate Deformity

HF G

B

Design Labeling

Incompatible with tools

Break in Packaging

Melting of AdhesiveTear in Plastic

Placement of plate in Ionic Circuit

Poor Implantation

Incorrect Sizing

Inadequate labeling

Ambiguous labeling

Ambiguous storage

Ambiguous screw-plate size combination

Allowance of poor screw-plate size combination

Poor Implantation

C

Displacement of screw in torsion

Subsidence displacing screw

D

Failure of Screw-to- Bone Union

Excessive screw rotation

permitted

Failure of static screw to lock to plate

Insufficient rotational screw movement allowance

E

Shearing of screw neck in torsion

Shearing of screw neck in subsidence

F

Too large of a diameter

Too small of a diameter

Plate surface interferes with static screw locking

Plate surface interferes with static screw locking

G

Buckling in torsion

Buckling in axial loading

H

Sub-failure stress deformation of plate