Is it normal to feeel a lump on the lumbar spine after a lumbar laminectomy?

Sometimes: It can be related to how you were sutured to developing a collection of fluid under your incision like a hematoma or seroma. Or more occasionally from a spinal fluid leak -sometimes it is do to a remaining adjacent spinous process that is now prominant as the others were removed as part of the laminectomy.

Yes and no: Early on this is likely swelling. If it persists then be sure to follow up with your surgeon to be sure it is not a fluid collection or infection.

Sometimes: After a laminectomy there is a defect present since the roof of the spine has been removed at one or more levels so the adjacent levels that are still present may feel like a lump. Sometimes, there is fluid that accumulates after surgery that feels that way. If you have a headache or fever and chills see you surgeon to make sure it's not an infection or spine fluid leak.