Rectus Abdominis Muscle Atrophy and Asymmetry After Pulmonary Lobectomy.

Introduction: Pulmonary lobectomy can result in intercostal nerve injury, leading to denervation of the rectus abdominis (RA) resulting in asymmetric muscle atrophy or an abdominal bulge. While there is a high rate of intercostal nerve injury during thoracic surgery, there are no studies that evaluate the magnitude and predisposing factors for RA atrophy in a large cohort.

Methods: A retrospective chart review was conducted of 357 patients who underwent open, thoracoscopic or robotic pulmonary lobectomy at a single academic center. RA volumes were measured on computed tomography scans preoperatively and postoperatively on both the operated and nonoperated sides from the level of the xiphoid process to the thoracolumbar junction. RA volume change and association of surgical/demographic characteristics was assessed.

Results: Median RA volume decreased bilaterally after operation, decreasing significantly more on the operated side (-19.5%) versus the nonoperated side (-6.6%) (P < 0.0001). 80.4% of the analyzed cohort experienced a 10% or greater decrease from preoperative RA volume on the operated side. Overweight individuals (body mass index 25.5-29.9) experienced a 1.7-fold greater volume loss on the operated side compared to normal weight individuals (body mass index 18.5-24.9) (P = 0.00016). In all right-sided lobectomies, lower lobe resection had the highest postoperative volume loss (Median (interquartile range): -28 (-35, -15)) (P = 0.082).

Conclusions: This study of postlobectomy RA asymmetry includes the largest cohort to date; previous literature only includes case reports. Lobectomy operations result in asymmetric RA atrophy and predisposing factors include demographics and surgical approach. Clinical and quality of life outcomes of RA atrophy, along with mitigation strategies, must be assessed.