DYSAESTHESIA ASSOCIATED WITH THORACIC SURGERY

Abstract

<h3>Introduction</h3> Chronic pain is experienced by 50% of patients following thoracic surgery. Neuropathic pain is commonly associated with dysaesthesia. Acute pain has been associated with dysaesthesia after sternotomy.(1) The aims of this study were to compare the total area of dysaesthesia after thoracic surgery on the operated with that on the contra-lateral non-operated side of the thorax and to determine whether the severity of acute postoperative pain is associated with the total area of dysaesthesia. <h3>Methods</h3> Fourteen patients admitted for elective thoracic surgery, either thoracotomy or video-assisted thoracic surgery (VATS), were recruited. Areas of dysaesthesia were identified by applying a monofilament and a needle in 1cm intervals down the anterior and posterior thorax from the level of the clavicle down to the level of the umbilicus, comparing the operated with the non-operated side as control. Areas of dysaesthesia were marked using different coloured pens then the areas were copied onto tracing paper of a known weight per area. Areas of dysaesthesia was estimated by weighing the tracing paper. Acute pain was scored using a verbal rating scale. <h3>Results</h3> There was no significant difference (p=0.101) in total area of dysaesthesia between the operated and the non-operated side [91 cm2 (Q1= 3, Q3=332); 0 cm2 (Q1=0, Q3=16)]. When comparing the total area of dysaesthesia between the operated side of the thorax, with the non-operated side of the thorax, 9 out of 14 patients (p= 0.101) had larger areas of dysaesthesia on the operated side and 4 out of 14 patients had a larger area of dysaesthesia on the non-operated side (p= 0.101). No significant correlations were found between the total area of dysaesthesia on the operated side with acute pain after inspiration (r = 0.341, p = 0.232) or at rest (r = 0.269, p = 0.352) <h3>Conclusion</h3> The difference in total area of dysaesthesia was not significantly different between the operated and non-operated sides of the thorax. The unexpected finding of areas of dysaesthesia on the non-operated side that was acting as control inflated the risk of Type II error. Unlike after sternotomy, no significant correlation was found between acute pain and the total area of dysaesthesia.