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. Author manuscript; available in PMC: 2015 Aug 1.
Published in final edited form as: J Neurosurg Spine. 2014 May 16;21(2):217–222. doi: 10.3171/2014.4.SPINE13669

Fig. 3.

Fig. 3

The preservation of headache relief after surgery over time in all patients up to 2 years postoperatively. Postoperative headache NDI scores at baseline (BL), 6 weeks (6W), 12 months (12M), and 24 months (24M) were 2.48, 1.07, 1.26, and 1.24, respectively. We found a statistically significant trend for very gradual worsening of pain level of 0.002 NDI headache points per week (p = 0.018), amounting to a change of just a tenth of a point worse per year. The 2nd year showed an attenuation of a significant portion of the pain relief from the first 6 weeks to 6 months after surgery, but with most of the improvement retained.