Efficiency of Long Lateral Mass Screws

Area of Science:

• Orthopedic Surgery
• Spinal Fusion Techniques
• Biomedical Engineering

Background:

• Cervical spine fusion commonly uses lateral mass screws (LMS).
• Existing LMS have limitations due to short screw length, potentially compromising postoperative fixation.
• A novel technique using long lateral mass screws (LLMS) was developed to address these limitations.

Purpose of the Study:

• To evaluate the outcomes of a novel long lateral mass screw (LLMS) insertion technique.
• To measure screw length, operative time, blood loss, and complication rates associated with LLMS.
• To assess screw deviation rates and analyze gender differences in screw length.

Main Methods:

• Retrospective evaluation of 35 patients undergoing LLMS posterior cervical fusion (2019-2021).
• Data collected included operative time, blood loss, complications, and inserted screw length.
• Screw deviation assessed via postoperative CT scans; gender differences analyzed using the Mann−Whitney U test.

Main Results:

• Mean operative time: 185 ± 51 min; mean blood loss: 236 ± 316 g.
• Average screw length: 21 ± 2.7 mm (males: 22.2 mm, females: 20.8 mm), with no significant gender difference (p > 0.01).
• A total of 183 screws were inserted with a deviation rate of 3.2% (6/183 screws).

Conclusions:

• The long lateral mass screw (LLMS) technique achieved a low deviation rate of 3.2%.
• LLMS enable strong posterior cervical fixation without reported complications.
• This study provides valuable measurements of screw length and deviation for the LLMS technique in clinical practice.