Objective: The median nerve can become compressed at multiple points in the arm, causing carpal tunnel-, pronator-, anterior interosseous-, or lacertus syndrome. Anatomical variations are potential reasons of persisting or recurrent symptoms of median nerve compression and are often recognized late. The objective of this study is to provide a comprehensive list of rare anatomical variations and malformations causing median nerve compression. Methods: A total of 62 studies describing median nerve compression due to an anatomical structure in adults published from 2000 in English were included. The findings were: 35 tenomuscular, 16 vascular causes, and 4 cases with nerve involvement. Only 1 osseous and 18 combined anomalies caused compression. In 18 cases, the anomaly was found in the proximal forearm. Results: In 44 cases, the median nerve was surgical released and 35 anomalies were completely resected. Persistent or recurrent symptoms were present in 13 cases. During follow-up, 1 case of recurrence was reported.Standard operative option for median nerve compression consists of an open median nerve release. Conclusions: In case of persistent or recurrent carpal tunnel syndrome, unilateral symptoms, the presence of a palpable mass, manifestation of symptoms at young age and pain in the forearm or upper arm, the surgeon has to rule out the presence of an anatomical anomaly. Complete resection of the anomaly is not always necessary. The surgeon should be aware of potential anomalies to avoid inadvertent damage at surgery.

Background: A Bochdalek hernia is one of the most frequently occurring congenital diaphragmatic hernias, and it occurs in 1 out of 2,500 births. Clinical cases of adults with symptomatic Bochdalek hernias are very rare. We describe a patient with an incarcerated Bochdalek hernia who underwent emergency surgery and presented with a recurrence after three years. Comparable cases in the literature were reviewed. Case Presentation: A 56-year-old woman presented to the emergency department with acute dyspnea and pain in the epigastrium shortly after gastroscopy. A CT scan showed right sided intrathoracic herniation of the ascending colon and signs of perforation of a hollow viscus. During the operation, a suture repair of a cecal perforation as well as of a diagrammatic lesion was performed. The thorax and abdomen were lavaged and drained. The postoperative course was uneventful. After 3 years, the patient presented with colic pain in the upper abdominal quadrants. A small recurrence of the Bochdalek hernia was observed on a computed tomography scan and was managed with watchful waiting. A systematic search of comparable acute cases of Bochdalek hernias was performed. Conclusion: An incarcerated right colon with a perforation in a Bochdalek hernia is extremely rare; only 11 comparable cases of right sided Bochdalek hernia with acute symptoms are described in the literature. Recurrent Bochdalek hernias are even rarer. As a delay in the diagnosis or a missed diagnosis can ultimately lead to death, adequate imaging is warranted when considering a recurrence of a Bochdalek hernia.