Cervical Spinal Stenosis in the Setting of Recurrent Shoulder Instability: A Nationwide Review of Records from 2007 to 2014.

Recurrent shoulder instability (RSI) and cervical spinal stenosis (CSS) may present with similar clinical symptoms. There is a paucity of data available investigating the incidence of CSS in patients with recurrent shoulder instability. For this reason, we investigated the incidence of CSS in patients with RSI and patient demographics, and compared characteristics of patients with CSS-RSI with those of patients with RSI alone. The Medicare Standard Analytical Files database in the PearlDiver supercomputer (Warsaw, Indiana) was carefully analyzed to identify all patients who had both CSS and RSI from 2007 to 2014. Patients were identified based on the international classification of disease codes (9th ed.). Annual national trends based on age, gender, body mass index (BMI), and geographic location were assessed. We identified 38,073 patients in the database during our study period. There was a significant increase in incidence of CSS in recurrent shoulder instability patients from 6.5% in 2007 to 9.2% in 2014 (p = 0.0027). Patients who were female (p = 0.0018), 65 to 80 years (46.3%; p < 0.0001), and with a BMI of 30-40 kg/m2 (34.1%; p < 0.0001) represented the greatest proportion of concomitant patients. Age less than 80 years was an independent risk factor for coexisting conditions (OR 1.47, 95% CI 1.32 to 1.64). In conclusion, the incidence of cervical spinal stenosis is increasing in patients with recurrent shoulder instability. Physicians should maintain high clinical suspicion for concurrent cervical spinal pathology, particularly in obese, young female patients with recurrent instability. Further investigation into the influence of these concurrent pathologies on patient outcomes is warranted.