**3. Results**

#### *3.1. Patient Characteristics*

A total of 1931 consecutive patients (female: 1219, male: 712) met inclusion criteria. Mean follow-up was 84 months; range, 12–192 months) (Table 1). Males had a slightly higher BMI than females (29.7 vs. 28.7; *p* < 0.01) and were more likely to require surgery for degenerative disease compared to other diagnoses (78% vs. 62%; *p* < 0.01) (Table 2). Females tended to be older than males at the time of surgery (61.7 years ± 12.8 vs. 59.7 years ± 14.1; *p* < 0.01). In general, females had a greater number of comorbidities compared to males (1.75 vs. 1.5; *p* < 0.01, Table 3). Comorbidities included in this study were autoimmune disorders, gastrointestinal disorders, depression, fibromyalgia, and thyroid disease. There was no difference in smoking status between groups (*p* > 0.01).

**Table 1.** Patient characteristics separated by gender.

