Background: Neck and back pain often occur simultaneously. The interconnection between their development after lumbar spine surgery has been studied little. This study aimed to assess the concurrent changes in back and neck pain and disability after lumbar spine surgery.

Methods: 1627 patients undergoing lumbar spinal surgery responded to a survey before surgery and up to 2 years after. Group-based trajectory analysis and multinomial regression analysis were used.

Results: The average age was 61.1 years and 53% were women. Concerning simultaneous changes in back and neck pain, two groups were identified. 82% experienced moderate preoperative back and no neck pain with quick and enduring pain relief after surgery. 18% with moderate preoperative pain in back and neck showed only a slight temporary postoperative pain relief. Three trajectory groups were identified based on changes in functional capacity. Group 1 (56%) had moderate disability caused by back pain (32.7%) and minimal disability caused by neck pain (15.7%) before surgery, which improved to 8.8% and 8.0% at 2 years. Group 2 (33%) had severe disability caused by back pain (48.4%) and moderate disability caused by neck pain (36.4%) before surgery, with postoperative values of 31.1% and 27.8%. Group 3 (11%) included patients who were housebound due to back pain (64.9%) and had severe disability caused by neck pain (56.7%); this group showed little improvement in disability after 2 years of follow-up. The higher probability of being classified into groups with worse outcomes was associated with female sex (RRR 1.54), a longer duration of preoperative pain (RRR 1.54 to RRR 1.51), older age (RRR 1.30) and higher BMI (RRR 1.44).

Conclusion: For most of the patients, neck pain was not a major problem, but disability due to neck pain was common. It is possible that this disproportion was real, and the patients undergoing lumbar spine surgery experienced limitations caused by neck pain. It is also possible that this was due to the similarity of the Neck Disability Index and the Oswestry Disability Index. However, it seems that postoperative changes in neck and back pain and the injury caused by either of them may be related and should be considered at least in some patient groups.