A trigonometric analysis of needle redirection and needle position during neural block

Area of Science:

• Anesthesiology
• Medical Imaging
• Surgical Navigation

Background:

• Effective regional anesthesia relies on accurate 3D anatomical understanding.
• Precise needle placement and repositioning are critical for successful procedures.

Purpose of the Study:

• To trigonometrically analyze the relationship between needle insertion angle and resulting needle position.
• To evaluate the impact of needle redirection angles on final needle placement.

Main Methods:

• A computer model was used to calculate changes in needle position.
• Needle advancement was simulated at various insertion and redirection angles (5° and 10° increments).
• The study considered needle lengths of 2, 3.5, and 5 inches and depths from 0.5 to 11.0 cm.

Main Results:

• A 5-degree needle redirection resulted in significantly less change in needle position compared to a 10-degree redirection.
• Increased needle depth and acute insertion angles strongly correlated with greater changes in needle position.

Conclusions:

• Incremental 5-degree needle redirection allows for precise anatomical surveying with predictable needle positioning.
• A 10-degree redirection significantly alters needle trajectory, increasing the risk of deviating from the target neural structure.