Failed Fusion Surgery ELDF Outcomes
Purpose of the study:
The study the clinical outcome and morbidity following the use of Endoscopic Lumbar Decompression and Foraminoplasty in the treatment of patients with continuing lifestyle degradation caused by back pain following lumbar fusion for chronic lumbar Spondylosis offers the opportunity to examine the importance of treating structures in the foramen with the role of the disc and intervertebral movement removed.
Materials & Methods:
This prospective study involved “day case” Endoscopic Lumbar Decompression and Foraminoplasty performed on 37 males, and 28 females with an average age of 53 years (42-81 years) and reviewed at 12, 24 and 48 months. The average preoperative duration of symptoms was 9.2 years (5 -27 years) and had undergone 1 – 7 previous open operations. 10 patients had undergone a caged ALIF, 16 an ALIF and instrumented PLIF, 20 an instrumented PLIF with intervertebral caging or mesh, 12 PLIF alone & 7 postero-lateral bone grafting. Further open surgery had been deemed unlikely to be of benefit. 30 had had a single level fusion.
A 50% reduction in back AND leg symptoms and a doubling in Oswestry Disability Index was deemed the threshold for a “clinically successful response”
Concordant symptoms were produced by spinal probing & discography at a non operated level in 13 patients. A clinically successful response was recorded in 56 (85%) at year 1, 50 (78%) at year 2 and 45 (70%) at year 3. 1 patient evidenced deterioration arising from symptoms at an adjacent level in year 2 and 3 in year 3. The mean pre-operative pain score was 8.6 (SD:1.4). Cohort integrity at the 3 year review was 60 (92%) and included 2 deaths. By year 3, 3 ELDs were revised at the same level, 3 at a level adjacent to the fusion and 3 within original fusion. Clinically 4 patients exhibited adjacent level symptoms impairing the outcome. There were no post-operative infections. 7 patients had a flare of symptoms lasting 3 – 8 weeks manifest as backpain and 4 had a transient parasthesiae (pins and needles) lasting up to 12 weeks. 1 patient required early same level revision for causalgic symptoms which were relieved.
The causal pain source involved tethering of the nerve to the disc wall, shoulder or facet joint osteophytes, superior foraminal ligament or impingement by disc wall aggravated by implant positioning or malplacement of pedicle screws.
Aware state surgery allows the definition of post fusion pain sources. Transforaminal endoscopic Foraminoplasty and decompression allows many patients deemed inoperable to be offered amelioration over a sustained period. Where the role of adjacent deterioration is excluded the benefit afforded by the procedure was 81% at year 3. The benefit occasioned demonstrates the importance of foraminal extradiscal pathology in the causation of axial and referred pain and highlights the opportunity to focus upon foraminal sources and limit surgical collateral damage and the need for a paradigm shift in treatment to Minimal Invasive Spine Surgery.