Correlation between thoracic kyphosis and dry needle length required to reach the pleural space needling the upper trapezius: A cadaveric fluoroscopic assessment

Abstract

BackgroundIt is unknown whether greater prone thoracic kyphosis increases pneumothorax risk during upper trapezius dry needling. ObjectivesTo fluoroscopically assess for a correlation between prone thoracic kyphosis and needle length required to reach the pleural space dry needling the upper trapezius in prone. DesignCadaveric study. MethodsProne thoracic kyphosis was assessed using dual bubble inclinometers. A 30 mm dry needle was inserted into the midsubstance of the upper trapezius perpendicular to the thoracic kyphosis. A single C-arm fluoroscopic image was obtained. This procedure was repeated with 40, 50, and 60 mm needles. Images were independently viewed by a radiologist to make a binary decision (yes vs. no) whether the needle had potentially broached the pleural space. ResultsFifteen cadaveric specimens with a mean age of 74.9 ± 9.7 and mean kyphosis of 21.5° ±7.7 were used. A 30 mm needle never reached the pleural space. The pleural space was potentially broached on one, four and six occasions by the 40, 50, and 60 mm needle respectively. The correlation between needle depth penetration and kyphosis was not significant (r = 0.03, p = 0.93). Longer needles (50 and 60 mm) were significantly (p = 0.0049) more likely to reach the pleural space than shorter needles (30 and 40 mm). ConclusionThoracic kyphosis was not correlated with needle length required to reach the pleural space. Clinicians may consider selecting shorter needles (<40 mm) to mitigate potential risk while dry needling the upper trapezius in prone.