Description

Schanz Screw

Q&A

Q1: What is a Schanz Screw and what is its primary function?

A1: A Schanz screw is a large, threaded pin specifically designed for external fixation systems. Its primary function is to securely anchor into the bone cortex and connect to an external frame, providing stable fixation for fracture management, limb lengthening, or deformity correction.

Q2: What are the key design features that distinguish a Schanz Screw?

A2: Key design features include:

Partial threading: Typically threaded only in the distal portion for secure cortical purchase

Self-tapping/self-drilling tip: Many modern versions have self-drilling tips

Robust core diameter: Designed to withstand mechanical loads

Proximal connection end: Configured to connect securely to external fixator rods

Q3: What are the most significant complications associated with Schanz Screws?

A3: Major complications include:

Pin tract infection

Neurovascular injury during insertion

Bone thermal necrosis from improper drilling

Pin loosening over time

Stress riser effect leading to peri-pin fractures

Q4: What is the difference between self-drilling and self-tapping Schanz Screws?

A4:Self-drilling screws have a sharp tip that eliminates need for pre-drilling

Self-tapping screws require a pilot hole but cut their own threads

Choice depends on bone quality and surgical preference

Q5: How do surgeons determine the appropriate size and length of Schanz Screws?

A5: Selection is based on:

Bone diameter and quality at insertion site

Soft tissue thickness requiring adequate clearance

Frame configuration and mechanical requirements

Patient anatomy and body habitus

Q6: How has the design of Schanz Screws evolved to improve outcomes?

A6: Modern improvements include:

Hydroxyapatite coating to enhance bone integration

Improved thread designs for better purchase

Tapered tips for easier insertion

Corrosion-resistant materials for long-term use

Standardized connections for universal compatibility