Tadpole system as new lumbar spinal instrumentation

Area of Science:

• Orthopedic Surgery
• Spinal Instrumentation
• Biomechanical Engineering

Background:

• Pedicle screw fixation in lumbar surgery carries risks, including nerve root injury.
• A novel hook-and-rod system, the Tadpole system, has been developed to address these concerns.
• This study evaluates the biomechanical and clinical outcomes of the Tadpole system.

Purpose of the Study:

• To assess the biomechanical stability of the Tadpole system compared to traditional methods.
• To evaluate the short-term clinical outcomes and safety of the Tadpole system in lumbar fusion.
• To determine the overall usefulness of the Tadpole system for spinal instrumentation.

Main Methods:

• A biomechanical study using cadaveric spines compared the range of motion (ROM) of the Tadpole system against pedicle screw fixation and control models.
• A clinical study involved 31 patients undergoing lumbar fusion with the Tadpole system.
• Clinical outcomes analyzed included operation time, bleeding, Japanese Orthopaedic Association (JOA) score improvement, instrumentation failure, and bone fusion rates at 2 years.

Main Results:

• The Tadpole system demonstrated biomechanical stability comparable to pedicle screw fixation, with a slightly greater ROM than pedicle screws but less than the normal spine.
• Clinical results showed a mean JOA score improvement of 70.9%, with 93.5% bone fusion at 2 years.
• The system proved safe, with no instances of spinous process fracture, spinal fluid leakage, nerve root injury, or postoperative infection; one case of instrumentation failure (hook dislocation) was reported.

Conclusions:

• The Tadpole system is a useful, easy-to-use, and safe spinal instrumentation technique for lumbar fusion surgery.
• It provides adequate biomechanical stability and achieves high rates of bone fusion.
• The low complication rate further supports its clinical utility.