Recent mri of cervical spine shows spinal cord swelling at c5- c6 , had acdf sugery in sept. why is there still swellinh?

Swelling may persist: Swelling within the cord is unusual. Not sure what you mean by that. Changes can occur in the cord from injury, either trauma, disc herniation or stenosis that some might call swelling. This is referred to as myelomalacia. This doesn't always change appearance after surgery. Presumably, you are not doing well from your surgery or you wouldn't have had another mri. Get a 2nd opinion.

It takes time: It takes many months for changes to the spinal cord to heal after the pressure is taken off. The hard part is to wait but it is important to keep up with physical therapy and light exercise in the meantime!

Hard to say: There are multiple potential causes. It still might be residual from what you had before surgery, there may be continued compression, or have been a surgical complication. Your surgeon would be the best to interpret the meaning of the study based upon your individual case. Thank you for your question.