Parietal Wall Hernia: A Rare and Avoidable Complication in Anterolateral Mini Thoracotomy Retroperitoneal Approach for Dorsolumbar Fractures

Aims& Objective: To evaluate the incidence of parietal wall hernia and its pathophysiology in cases of traumatic dorsolumbar fractures operated via anterolateral mini thoracotomy retropleural& retroperitoneal approach. Material and Methods: A retrospective analytical study of patients of traumatic dorsolumbar fractures was carried out in our institute from Jan 2015 to June 2018. A total of 50 patients (n = 50) out of 130 were managed by this retropleural / retroperitoneal mini thoracotomy approach. There were 40 males and 10 females (M: F= 4: 1). Out of these, 34 patients underwent single rib resection depending upon the level of fractured vertebra and 16 patients underwent excision of 11th& 12th ribs. This was followed by diaphragmatic sparing retroperitoneal approach for performing corpectomy, placement of expandable cage and fixation with screw and rod. The mean follow up of the patients was 18 months (range 6 - 30 months). Thickness of the abdominal wall muscle was measured by follow-up computed tomography (CT) scan. Compound muscle action potentials (CMAPs) of the abdominal muscle were examined in these three patients. Results: 3 out of the 50 (6 %) patients developed parietal wall hernia. However, none of these patients showed features of obstruction. The thickness of the abdominal wall muscle was reduced at the operated site as measured on CT vis a vis the normal side. CMAP of abdominal rectus muscle was low/non recordable in comparison to the contralateral side. Conclusions: All these 3 patients of parietal hernia had undergone resection of two ribs (11th& 12th) and were the initial cases of this study. Subsequently a modified approach with single rib resection and sparing of latissimus dorsi has enabled in reducing this complication. Parietal wall hernia mostly occurs due to damage of the 11th& 12th intercostal nerves. This results in atrophy of the rectus and lateral abdominal wall musculature leading to parietal hernia without true facial defect. Obstruction in such cases is extremely unlikely and hence the management remains conservative.