A Simple Versatile Technique to Retrieve Polyaxial Tulip-head Spinal Pedicle Screws Following Failed Pedicle Screw Removal: A Technical Note With Analysis of Efficacy and Outcomes

Abstract

Introduction: With increase in the number of thoracolumbar spine surgeries using pedicle screw instrumentation, there is a proportionate increase in the number of revision surgeries requiring implant removal. Lack of standardization in manufacturing spinal pedicle screws has led to diverse variations in their design and dimensions. Removal of polyaxial pedicle screws becomes extremely difficult when there is a mismatch between their tulip-head and the screwdriver. With the rapidly changing concepts and designs of spinal pedicle screws this problem may arise when the appropriate pedicle screw instrumentation is out of production. There may be a need for special instruments or an array of screwdrivers of various dimensions/designs to overcome this problem. We describe a simple yet versatile technique to remove polyaxial tulip-head pedicle screws using commonly available instruments in the spinal instrumentation set. Materials and Methods: Polyaxial screws were removed after converting them into monoblock screws using the appropriate set-screw screwdriver, a 25-mm long 5.5 mm rod, and a counter torque wrench. Results: Using this technique we have successfully removed 167 screws in 53 revision surgeries [instrumented fusions for lumbar degenerative diseases (n=21), thoracolumbar fractures (n=15), and scoliosis (n=17)]. No failed retrievals or complications like pedicle breach or neurological deficit were observed. Discussion: The described technique is simple to execute, effective, quick, and safe. It is versatile and can be used to remove polyaxial pedicle screws of any design in the thoracic and lumbar spine using the commonly available instruments in the routine spinal instrumentation set (appropriate set-screw screwdriver, a 25-mm long 5.5 mm rod, a counter torque wrench).

Unique Procedure to Remove Pedicle Screw without Compatible Instrumentation: Case Report and Review of Literature

“…In U-rod technique described by Kose et al, surgeon used Allen key to remove cap screws and the screw is placed in the U-shaped rod after removing the rods [ 8 ]. Uvaraj and Bosco in his study first removed cap screw followed by connecting rod and after cutting rod to 25-mm length reapplied it over polyaxial screw head converting it into single system and then removed pedicle screw using counter torque wrench and appropriate size screwdriver [ 9 ]. However, the above methods will work only if cap screw holding the rod with the screw can be removed.…”