The final draft of the Iranian versions of the CNFDS and mJOA were administered to a sample of newly diagnosed CSM patients attending the neurosurgery clinic of a large teaching hospital in Tehran, from April 2007 to June 2013. CSM was diagnosed on the basis of appropriate history, clinical examination, and investigations, notably magnetic resonance imaging or computed tomography (CT) scan of the cervical spine. There were no restrictions on patient selection with regard to types of CSM, age or other characteristics. The exclusion criteria were prior cervical spine surgery or other coexisting pathology that might result in functional impairment. All patients had the typical symptoms of CSM and were surgical candidates.

The key to the treatment of the CSM is to remove the pressure from the spinal cord. Surgical methods to decompress the spinal cord included three approaches: (1) from the front of the neck as anterior cervical discectomy and fusion, anterior cervical corpectomy, and (2) from the back of the neck as cervical laminectomy, cervical laminectomy and fusion, cervical laminoplasty, and (3) a combined procedure [19]. All three approaches were applied to the patients.

The CNFDS (Appendix 1) is designed to evaluate the disability experienced by CSM patients. It is a self-administered questionnaire that consists of three sections including 15 items that evaluates the impact of neck pain including the patient's perception of the future impact of neck pain (3 items including 1, 5, and 15), disability during everyday activities (9 items including items 2, 3, 4, 5, 7, 8, 9, 10 and 12) and social interaction and recreation (5 items including item 6, 9, 11, 13 and 14). Each item has three possible response categories (yes=0, occasionally=1 and no=2) for the first 5 items and the remaining items are scored in the reverse (yes=2, occasionally=1 and no=0). The total score ranges from 0 to 30, with higher score indicating greater disability [17].

The Iranian version of the mJOA was simultaneously administered to patients. It is a self-administered, disease-specific tool modified from the JOA score [89] that consists of four sections including 22 items: motor dysfunction of the upper extremities (6 items), motor dysfunction of the lower extremities (8 items), sensation (4 items) and sphincter dysfunction (4 items). The score the respective section ranges from 0 to 5, 0 to 7, 0 to 3 and 0 to 3, giving a total score ranging from 0 to 18. Higher scores indicate less disability. In this study the total mJOA was calculated for assessment. In a previous study by this group, the Iranian version of mJOA was documented as a reliable and valid measure of motor, sensory and sphincter dysfunctions among CSM patients [9].

Patients were assessed preoperatively and postoperatively. CNFDS and mJOA scoring were completed at the same time on the day before surgery and at the end of follow-up. The recovery rate of mJOA score (%) was also assessed using a previously published formula [20]: recovery rate (%)=[postoperative score–preoperative score]/[full score (18)–preoperative score]×100.

Statistical analyses were performed using PASW ver. 18.0 (SPSS Inc., Chicago, IL, USA). A p-value of <0.05 was considered statistically significant. Correlation between the CNFDS and the mJOA was assessed using Pearson's correlation coefficient. Values of 0.40 or above were considered satisfactory (r≥0.81–1.0 as excellent, 0.61–0.80 very good, 0.41–0.60 good, 0.21–0.40 fair, and 0.0–0.20 poor) [21]. CNFDS and the mJOA scores were calculated preoperatively and postoperatively using the paired t-test to capture the changes after surgery.

The Ethics Committee of Shahid Beheshti University of Medical Sciences, Tehran, Iran, approved the study.

Ninety five patients with CSM were studied. Their mean age was 58.2 (standard deviation, SD=8.7) years. The mean symptom duration was 11.6 months (range, 1 to 59 months). The characteristics of patients and their scores on the mJOA are presented in Table 1. Most patients with CSM had a developmental narrow spinal canal, and the decompressive laminae were distributed from C2 to C7 levels. The number of decompressed lamina was 2.6 (SD=1.0). Most patients with CHD had a one- or two level discectomy and were distributed from the C2 to C7 levels. The anterior approach (discectomy/corpectomy with instrumented fusion; n=72), posterior approach (either laminectomy and fusion or laminoplasty; n=20), and combination of both anterior and posterior approaches (n=3) were performed for decompressive spinal surgery. Statistically differences were observed preoperative and postoperative assessments indicating improvements in outcomes and functionality in all subscales (p<0.001). However, there was no significant difference between patients with CSS and CHD (p≥0.05).

CNFDS total score correlated strongly with mJOA total score preoperatively and at the end of follow-up, lending support to its good convergent validity (r=–0.81 and –0.82, respectively; p<0.001) (Fig. 1). In all instances, CNFDS and mJOA tools were able to detect changes after the intervention (surgery), indicating improvements in all subscales. The outcomes are shown in Tables 2 and 3. The mean mJOA recovery rate was 51.8% (SD=13.1%), ranging from 23.0% to 88.8%.