Cervical Cannulated Screw

Product Overview

The Cervical Cannulated Screw is a specialized internal fixation device designed for anterior minimally invasive stabilization of Anderson-D'Alonzo Type II and shallow Type III odontoid fractures. Manufactured from high-strength medical-grade titanium alloy, this cannulated screw features a self-tapping single-thread design that provides secure purchase and compression across the fracture site, promoting bony healing while maximizing preservation of cervical rotational function. The screw head features a low-profile, smoothly rounded contour that conforms to the anterior vertebral body anatomy after implantation, minimizing soft tissue irritation. Available in 3.5 mm and 4.0 mm diameters with lengths ranging from 24 mm to 46 mm in 2 mm increments, this system accommodates diverse anatomical variations. The percutaneous minimally invasive technique enables precise fracture reduction and fixation while preserving atlantoaxial joint motion, making it an ideal treatment option for patients requiring stable odontoid fracture fixation with preservation of cervical mobility.

Indications for Use

The Cervical Cannulated Screw is indicated for the following clinical scenarios:

• Anderson-D'Alonzo Type II odontoid fractures requiring anterior screw fixation for stabilization and compression.

• Anderson-D'Alonzo shallow Type III odontoid fractures where anterior screw fixation provides adequate stability.

• Acute odontoid fractures in patients where preservation of atlantoaxial rotational function is a priority.

• Odontoid fractures in younger patients where motion preservation is preferred over fusion.

• Type II odontoid fractures with minimal displacement where percutaneous fixation is feasible.

• Patients with odontoid fractures who are candidates for anterior minimally invasive fixation rather than posterior fusion.

Key Advantages

The Cervical Cannulated Screw offers a range of distinct clinical benefits that enhance surgical outcomes and patient recovery.

Minimally Invasive Percutaneous Technique – The system is specifically designed for percutaneous anterior placement, significantly reducing soft tissue trauma, blood loss, and postoperative pain. The cannulated design enables precise over-the-wire placement under fluoroscopic guidance, facilitating accurate screw insertion while minimizing surgical exposure and recovery time.

Preservation of Cervical Rotational Function – Unlike posterior atlantoaxial fusion procedures that sacrifice C1–C2 motion, anterior odontoid screw fixation preserves the atlantoaxial joint's rotational function. This is particularly important in younger patients where maintaining cervical mobility significantly impacts quality of life and functional outcomes.

Cannulated Design for Precise Placement – The cannulated screw accepts a guide wire, enabling controlled, over-the-wire placement under fluoroscopic guidance. This design enhances accuracy and reduces radiation exposure to the surgical team while ensuring optimal screw trajectory across the fracture site.

Self-Tapping Single-Thread Design – The self-tapping single-thread configuration provides secure purchase in the cancellous bone of the odontoid process and C2 vertebral body. The single-thread design enables controlled advancement with excellent purchase, providing stable compression across the fracture site to promote bony healing.

Low-Profile Anatomical Head Design – The screw head features a low-profile, smoothly rounded contour that conforms to the anterior vertebral body anatomy after implantation. This design minimizes the risk of soft tissue irritation, reduces the potential for dysphagia, and optimizes patient comfort.

Comprehensive Sizing Options – Available in 3.5 mm and 4.0 mm diameters with lengths ranging from 24 mm to 46 mm in 2 mm increments, the system provides extensive flexibility for addressing different anatomical variations and fracture patterns. The comprehensive range of lengths ensures an optimal fit for patients of all sizes.

Compression-Facilitating Design – The screw design is optimized to provide effective compression across the fracture site, promoting primary bone healing. The lag-screw effect achieved through the differential thread design enhances fracture reduction and stability.

Titanium Alloy Construction – Manufactured from medical-grade titanium alloy, the screw offers excellent biocompatibility, corrosion resistance, and MRI compatibility. The modulus of elasticity is closer to cortical bone than stainless steel, providing physiological load transfer and reducing stress shielding.

Technical Specifications & Sizing

Size Range Overview

The Cervical Cannulated Screw is available in two diameters and a comprehensive range of lengths to accommodate diverse patient anatomies and fracture patterns.

Key Specifications:

• Diameter: 3.5 mm, 4.0 mm

• Length: 24–46 mm (2 mm increments)

• Thread Type: Self-tapping single-thread design

• Head Type: Low-profile, smoothly rounded for anatomical fit

• Cannulation: Accepts guide wire for over-the-wire placement

• Material: Medical-grade titanium alloy

• Application: Anterior odontoid fracture fixation

Detailed Dimension Table

Note: All screws are cannulated and compatible with standard guide wires. The screws are available in sterile and non-sterile configurations. Length selection should be based on preoperative CT measurement of the odontoid process and C2 vertebral body, ensuring adequate purchase across the fracture site without over-penetration. The 2 mm incremental length progression enables precise anatomical matching.

Recommended Companion Instruments

The Cervical Cannulated Screw System is supported by a dedicated instrument set for precise, minimally invasive implantation:

RFQ – Request for Quotation

Q1: What is the primary indication for the Cervical Cannulated Screw?
A: The primary indication is the anterior minimally invasive fixation of Anderson-D'Alonzo Type II and shallow Type III odontoid fractures. These fractures occur at the base of the dens and are among the most common cervical spine fractures. The system provides stable fixation across the fracture site, promoting bony healing while preserving the rotational function of the atlantoaxial joint—a significant advantage over posterior fusion procedures that sacrifice C1–C2 motion.

Q2: How does the cannulated design benefit the surgical technique?
A: The cannulated design enables over-the-wire placement under fluoroscopic guidance, facilitating precise screw insertion with minimal soft tissue dissection. The guide wire is placed across the fracture site under image guidance, and the screw is then advanced over the wire, ensuring optimal trajectory and reducing the risk of malposition. This technique significantly reduces surgical time and radiation exposure while improving screw placement accuracy.

Q3: What is the recommended screw length for different patient anatomies?
A: The appropriate screw length is determined by the combined length of the odontoid process and the C2 vertebral body, measured on preoperative CT imaging. For most patients, the combined length is 30–40 mm, with the 3.5 mm diameter screws typically used in patients with smaller anatomy and the 4.0 mm screws used in larger patients. We recommend measuring the distance from the tip of the dens to the anterior-inferior cortex of the C2 vertebral body and selecting a screw that is 2–4 mm shorter than this measurement to avoid over-penetration.

Q4: Are sterile-packaged screws available?
A: Yes, the Cervical Cannulated Screws are available in both sterile and non-sterile configurations. Sterile screws are individually packaged and ready for immediate use, simplifying OR preparation and reducing the risk of contamination. Non-sterile screws require sterilization prior to use. Please specify your preference when placing an order.

Q5: What is the clinical advantage of the low-profile head design?
A: The low-profile, smoothly rounded head design conforms to the anterior vertebral body anatomy, minimizing the risk of soft tissue irritation and reducing postoperative dysphagia. This is particularly important in anterior cervical surgery where prominence of hardware against the esophagus can lead to swallowing difficulties. The streamlined profile also reduces the risk of adjacent segment irritation and provides optimal patient comfort.

Q6: Can the screw be used in patients with osteoporosis or compromised bone quality?
A: While the screw is designed to provide secure fixation through the self-tapping single-thread design, careful patient selection is essential in cases of compromised bone quality. For osteoporotic patients, we recommend thorough preoperative assessment of bone quality using CT imaging and consideration of adjunctive fixation techniques if necessary. In some cases, the 4.0 mm diameter screw may provide improved purchase compared to the 3.5 mm option. Please consult the surgical technique guide for specific recommendations based on individual patient characteristics.