Analysis of posterior spinal wiring in a validated rabbit model

Area of Science:

• Spinal fusion research
• Orthopedic surgery
• Biomechanical testing

Background:

• Posterior spinal fusion is a common surgical procedure.
• Assessing fusion rates and biomechanical properties is crucial for surgical success.
• Minimally invasive techniques are continually being explored.

Purpose of the Study:

• To evaluate the efficacy of mamillary and spinous process base wiring for L5-L6 posterolateral fusion in a rabbit model.
• To compare fusion assessment methods, specifically radiography versus manual palpation.
• To determine the impact of internal fixation and infection on fusion, stiffness, and strength.

Main Methods:

• A rabbit model was used to perform L5-L6 posterolateral fusion.
• Mamillary and spinous process base wiring techniques were employed.
• Specimens were assessed for fusion rate using radiography and manual palpation.
• Biomechanical testing (stiffness and tensile strength) was performed on fused and non-fused specimens.
• Infection rates associated with internal fixation were recorded.

Main Results:

• Mamillary and spinous process base wiring did not improve fusion rates, stiffness, or strength.
• Radiography underestimated fusion rates compared to manual palpation (37% vs. 68%).
• Fused specimens demonstrated significantly greater stiffness (67.2 N/mm vs. 41.1 N/mm) and strength (177 N vs. 121 N).
• Deep wound infection was more prevalent with internal fixation (43% vs. 21%).
• Non-infected specimens were stiffer (63.3 N/mm vs. 43.0 N/mm) and stronger (176 N vs. 107 N) than infected specimens.

Conclusions:

• The evaluated wiring techniques did not enhance L5-L6 posterolateral fusion in the rabbit model.
• Manual palpation is a more accurate method for assessing spinal fusion than radiography.
• Fusion significantly improves spinal biomechanical properties.
• Deep wound infection negatively impacts spinal fusion outcomes and biomechanical integrity.