Patient characteristics

A retrospective observational cohort study of ulnar nerve compression at the elbow at Department of Hand Surgery, Plastic Surgery and Burns, Linköping University Hospital, Linköping, Sweden, where outcome of surgery was analyzed in 173 patients [29 bilateral surgery; thus, in total 202 cases (19)], was earlier performed. A majority of the original 173 patients (202 cases) had a concomitant affection of another nerve in operated arm and one third had a concomitant affection of another nerve in contralateral arm (Figure 1). Around 50% had an MRI performed preoperatively, with referral to radiology of whom 30% had signs of nerve root affection (level not specified) according to the patients' charts. For details of the patient cohort see Giöstad and Nyman 2019 (19).

Flow chart of included patients in relation to previously published study of surgically treated patients (19). For variables, please see Table 1.

In the present study, pre- or postoperative available MRI images were retrieved and re-evaluated (for details see below). The inclusion criterion of the present study was availability of MRI examination with images that could be re-evaluated as described below. Background data of the present 62, out of the earlier presented 173, patients were extracted from the file based on the patient charts, including age, sex, uni- or bilateral surgery, McGowan grading for severity of preoperative ulnar nerve problems (20), other nerve compression lesion(s) and surgery for other hand condition in the same or opposite arm, shoulder or neck problems, and presence of polyneuropathy and diabetes. Data of outcome was also extracted from the file, consisting of DASHscore and replies from two further questions: “How do you think the hand/works today compared to before surgery?” and “Are you pleased with the result from the surgery?”; both graded as completely fine – improved vs. unchanged—worse; data from 173 patients earlier published (19).