Abstract
Introduction: Recent evidence from the Swedish Lumbar Spine Group has confirmed the anecdotal opinions of many spinal surgeons that fusion for persistent back pain can be a very effective treatment. However, it is clear that many more variables operate in determining clinical success than just radiological evidence of solid fusion. The very careful selection of patients for low back surgery is, in the opinion of the authors, the most important predictor of success. This paper addresses this issue and presents data to show why clinical failure can coexist with radiological success.
Methods: Between October 1997 and January 2001, 3600 spinal fusion using Diapason pedicle screw instrumentation and Brantigan anterior interbody fusion cages was performed on 25 patients. During this period 5,850 new outpatients with back pain were assessed in the low back clinic. Patients were selected by the following criteria: Low back pain of two years or more duration; Pain resistant to all non-operative and minimally invasive treatments; Normal psychosocial profile; Normal body mass index; Non-Smokers; Single or two level disease on MRI proven to be painful by provocative discography; No current insurance or workers-compensation claims. Postal follow-up was at a minimum of 2 years post-surgery (mean 47 months) using the Low Back Outcome Score (LBOS) and x-rays taken at the two-year clinic follow-up were independently assessed to determine fusion.
Results: 24 patients returned the questionnaire (96%). Only 20 (83%) patients had ‘good’ or ‘excellent’ results, as defined by the LBOS. However, 92% of patients stated that they would opt to have a circumferential fusion again, if guaranteed the same post-operative result. The same number of patients stated they would recommend the treatment to friend or family member. Analysis of the post-operative radiographs revealed that spinal fusion (as defined by the Brantigan and Steffee criteria) was present in all 25 cases.
Conclusions: Our opinion that patient selection is the most important predictor of satisfactory outcome in spinal surgery is demonstrated in this study by the mismatch between the clinical and radiological results. We have identified the causes of clinical failure in this group of patients as: Multiple sites of musculoskeletal pain confounding the LBOS; Neuropathic leg pain that cannot respond to surgical treatment; More than two previous spinal operations; Excessive pre-operative disability and functional loss that confounds the LBOS; Poor psychosocial profile.
Stringent application of rigid selection criteria might improve outcomes in lumbar spinal fusion so that clinical and radiological results correlate more closely. However, even with adherence to such rigid criteria, the outcome tool (LBOS) may be confounded and a more holistic assessment of outcome, including a more sensitive subjective assessment of satisfaction, might be a better measure.
The abstracts were prepared by Dr Robert Moore. Correspondence should be addressed to him at Spine Society of Australia, c/o the Adelaide Centre for Spinal Research, Institute of Medical and Veterinary Science, PO Box 14, Rundle Mall, Adelaide SA 500, Australia.
