Followup was carried out at 3 months and one year after surgery. Pre-operative depressive disorders tended not to do well.Smoking has been shown to increase the incidence of post operative infection as well as decrease fusion rates. One study showed 90% of post operative infections occurred in smokers, as well as myonecrosis (muscle destruction) around the wound. Pathology
Before the advent of CT scanning, the pathology in failed back syndrome was difficult to understand. Computerized tomography in conjunction with metrizamide myelography in the late 1960s and 1970s allowed direct observation of the mechanisms involved in post operative failures. Six distinct pathologic conditions were identified:

Recurrent or persistent disc herniation
Spinal stenosis
Post operative infection
Epidural post-operative fibrosis
Adhesive arachnoiditis
Nerve Injury

Recurrent or persistent disc herniation
Removal of a disc at one level can lead to disc herniation at a different level at a later time. Even the most complete surgical excision of the disc still leaves 30–40% of the disc, which cannot be safely removed. This retained disc can re-herniate sometime after surgery. Virtually every major structure in the abdomen and the posterior retroperitoneal space has been injured, at some point, by removing discs using posterior laminectomy/discectomy surgical procedures. The most prominent of these is a laceration of the left internal iliac vein, which lies in close proximity to the anterior portion of the disc. In some studies, recurrent pain in the same radicular pattern or a different pattern can be as high as 50% after disc surgery.
Surgery
Surgical treatment of arterial manifestations of BD bears many pitfalls since the obliterative endarteritis of vasa vasorum causes thickening of the medial layer and splitting of elastin fibers. Therefore, anastomotic pseudoaneurysms are likely to form, as well as pseudoaneurysms at the site of the puncture in case of angiography or endovascular treatment; furthermore, early graft occlusion may occur.For these reasons, invasive treatment should not be performed in the acute and active phases of the disease when inflammation is at its peak. The evaluation of diseases activity is usually based on relapsing symptoms, ESR (erythrocyte sedimentation rate), and serum levels of CRP (C‐reactive protein).Endovascular treatment can be an effective and safe alternative to open surgery, with less postoperative complications, faster recovery time, and reduced need for intensive care, while offering patency rates and procedural success rates comparable with those of surgery. This notwithstanding, long‐term results of endovascular treatment in BD are still to be determined. Epidemiology
The syndrome is rare in the United States, Africa and South America, but is common in the Middle East and Asia, suggesting a possible cause endemic to those areas. A theory suggested that past exposure to lethal infectious agents might have fixed the genetic susceptibility factors to Behçets disease in those area. An estimated 15,000 to 20,000 Americans have been diagnosed with this disease. In the UK, it is estimated to have about 1 case for every 100,000 people.