Thanks for writing to us.
Lump after spinal fusion
could be due to herniation at surgical site or injury
to surrounding tissue.
Direct clinical examination is needed to know the cause of lump.So I suggest you to consult your surgeon for direct examination.You might required a CT scan
under his/her guidence for better diagnosis.
Hope this will helps you
Wishing you good health...
Dr Saurabh Gupta.