A 10-year follow-up of transpedicular screw fixation and intervertebral autogenous posterior iliac crest bone graft or intervertebral B-Twin system in failed back surgery syndrome
Authors: Cincu Rafael , Lorente Francisco , Gomez Joaquin , Eiras Jose , Agrawal Amit 
Published: November 2014

Background: The spine surgeons have been combining anterior and posterolateral fusion (circumferential fusion) as the final solution to treat spinal disorders and many have been using it to treat failed back surgery syndrome (FBSS). In present study, we analyzed and compared the clinical and radiological outcomes in patients with transpedicular screw fixation and intervertebral autogenous posterior iliac crest bone graft or in patients with transpedicular screw fixation and intervertebral B-Twin system for FBSS with a follow-up period of 10 years after the surgery. Materials and Methods: This study was a retrospective case study performed on 55 patients with FBSS. Clinical and radiological changes were compared between the two groups of patients on the basis of improvement of back pain, radicular pain, and work capacity. Outcome was measured in terms of Oswestry Low Back Pain Disability Index, and the changes in pain and function were documented every year from before surgery until 2012. We analyzed the evolution of 55 cases of FBSS those underwent segmental circumferential posterior fusions from June 2001 to February 2003, operated by a single surgeon and followed up during 10 years until February 2012. The patients were divided into 2 groups: In 25 patients, posterolateral fusions with Legacy™ (Medtronic, Inc. NYSE: MDT) screws and intersomatic autogenous posterior iliac crest bone graft was performed, and, in 30 patients, posterolateral fusions with the same screws and intersomatic fusion B-Twin (Biomet Spain Orthopaedics, S.L.) system was performed. In all cases, we used posterior lumbar interbody fusion (PLIF)/transforaminal lumbar interbody fusion (TLIF) approach for intervertebral graft, and the artrodesis was supplemented at intertransverse level with Autologus Growth Factor (AGF-MBA INCORPORADO, S.A.). The outcome was measured in terms of Oswestry Low Back Pain Disability Index, and the changes in pain and function were documented every year and compared from before surgery to the final follow-up visit. Preoperative and postoperative scores were available for all patients. Results: The average age of these patients was comparable in both groups (mean age 42.6 versus 50.2 years). The average follow-up period was 200.6 months in the first group (screws and intersomatic bone) and 184.4 months in the second group (screws and B-Twin). In the autologus bone graft group, the CT scan and Rx study revealed loss of height of intervertebral space between 25% and 45% of 24 h postoperative height of intervertebral operated disc, and the patients continued to lose the height until 20 months after the surgery. In the B Twin group, the CT scan and Rx study revealed a loss of height of the intervertebral level of 8-12% over a period of 9 months follow-up, followed by stability. A total of 31 patients (55%) had improved Oswestry Low Back Pain Disability Index >40% of the total possible points, although this did not reflect in PSI or return to work rate. Conclusions: The patients with rigid fixation do well in terms of correction of lumbar lordosis, but they do not do well in terms of recurrence of pain. Furthermore, they need some kind of intervention to control pain after the first year after surgery. In patients in whom bone graft is used, although they do not maintain and sustain the lumbar lordosis in the long term, they have less recurrence of pain with less chances of intervention for pain control.