I'm 17 months post op two level lumbar fusion surgery and still having muscle tightening, muscle fatigue, and muscle spasms...is this common?

It can be: If you had a posterior approach for your surgery, the muscles can be damaged from the exposure and can result in chronic deconditioning and muscular pain. You may benefit from a walking program and physical therapy to strengthen your core and lumbar muscles. Finally, it is important to confirm that you are indeed fused.

There may be other : Levels that are unstable in the back that are causing the problem , prolotherapy can deal with forcing the other levels to heal without more surgery. Prolotherapy can help. Visit www.Getprolo.Com or www.Aaomed.Org for a doctor and for info.

17 months out: Being 17 months out and still having significant problems could mean problems at other levels, as dr. Stein mentioned, or a lack of successful (solid) fusion at the operated level(s). I would definitely consider discussing with your surgeon and getting new imaging studies.