Spinal gas may be located within intervertebral spaces or facet joints, which identified by CT scan easily. In exceptional cases due to anulus rupture an epidural gas bubble may be trapped within a nonspecific fibrous cyst wall and may become compressive .Other sources of EG include local structures and processes, pyogenic infections, intestinal necrosis .
EG after TLIF is not described in the literature. Thus we presented our case. TLIF approach traverse the annulus fibrosus making a tear enlarging the channel between intradiscal and epidural space. That causes expelling of the intervertebral gas to the spinal canal in the anterior epidural space. Gas trapping leads to formation of a chronic blister-like and constraint to nerve root, .It should be kept in mind, that infectious and more serious causes should be ruled out depending on the clinical presentation and Para clinical results They were normal in this case.
Clinical signs and symptoms are the major determinants in treatment selection.Whereas, conservation treatment showed postoperative EG resorption with time by Capelle and Kraus and Ilica et al, surgical management was the main stay of treatment by Souftas,Raynor and Saint-Louis and Kaymaz et al.While others in the literature say that needle aspiration ,or surgery is needed after the failure of conservative management including absolute bed rest ,steroid, nonsteroidal anti-inflammatory drug medication when EG confirmed radiologicaly, , .In contrast Open surgery is definitely required in presence of chronic encapsulated EG.
We proceeded to open surgery after no response to the conservative therapy and the presence of blister like capsulated EG on Ct scan(Fig. 1). The open approach through laminectomy removes totally the chronic EG (Fig. 2).