It’s not uncommon to have root swelling after a surgical decompression causing recurrent leg pain.
The possible causes of increased leg pain after a period of relief post-microdiscectomy surgery are inflammation of the nerve, seroma, recurrent herniation and infection with much more rare conditions like facet fracture.
Inflammation is common after decompression of the root. A compressed structure that was injured will “swell” and become congested. Oral steroids and time are the best treatment.
Seroma is a common condition. Fluid exudes from surgical sites and can build up and congest and compresses the nerve root. Seromas typically resorb after some time but occasionally need to be aspirated by needle. This is diagnosed by MRI and treated by needle aspiration.
Recurrent herniation occurs in 15% of patients and normally increase pain significantly. Recurrent weakness and a “tighter” leg (SLR) are common. If the recurrence is not too large, sometimes an epidural injection can be helpful. A redo microdiscectomy is not uncommon in the face of a recurrent herniation.
Infection should be rare at less than 1% of all surgeries. Interestingly, many patients do not have fevers or chills but have increased back pain that translates to leg pain eventually. Lab tests are the beginning for diagnosis. Diagnosis is by lab tests and patient symptoms.