Clinical StudyOutcomes of extended transforaminal lumbar interbody fusion for lumbar spondylosis
Introduction
Fusion of the spine was first described in 1911 by Albee et al. as an operation for Pott’s disease, using a tibial graft for stabilization, [1] and by Hibbs et al. for stabilizing spinal deformities such as scoliosis [2]. Chandler et al. were the first to use spinal fusion for treatment of lower back pain and sciatica [3]. Barr proposed the combined use of discectomy and fusion to overcome the problem of discectomy alone, which left patients with residual pain due to underlying structural disc weakness [4].
Lumbar interbody fusion is now an accepted treatment for a variety of spinal disorders including trauma, infectious and neoplastic conditions [5]. It involves placement of an implant (spacer, graft or cage) within the intervertebral space, after a discectomy and end plate preparation. Currently, lumbar interbody fusion is performed using four main approaches, posterior (PLIF), transforaminal (TLIF), anterior (ALIF), and lateral (LLIF). There is no evidence that one approach is superior to the others. These operations can also be performed using mini-open or minimally invasive (MIS) approaches [6]. Interbody fusion has been reported to have lower rates of postoperative complications and pseudoarthrosis [7], [8].
Posterolateral fusion places the graft in the posterolateral gutter to allow fusion from one transverse process to another. This avoids stenosis, which can be caused by a direct posterior approach to fusion [10], [9]. The TLIF, a modified and unilateral approach to the PLIF, was first described by Harms et al. in 1982 [11]. It gained popularity after further work by Harms et al. in the 1990s [12]. The technique was developed with the view to achieve a circumferential fusion, with minimal risk to neural structures or the need for two staged operations. Retraction on the neural structures in TLIF is less than PLIF, and hence, can be safely performed above L2 as there is less conus medullaris retraction and risk for injury. TLIF preserves the interspinous ligament and spinous processes posterior to the thecal sac, as well as other midline structural supports [13]. TLIF may be preferable for revision surgery of a prior posterior approach, especially when an anterior approach is problematic or the surgeon is not familiar with ALIF. These benefits have led to TLIF becoming increasingly popular over the last 15 years. Multiple versions of this technique have now emerged including unilateral instrumented fusion, unilateral pedicle screws with contralateral facet screws and, more recently, MIS techniques for interbody fusion with bilateral pedicle screws, with or without a posterolateral fusion [14], [15], [16], [17]. The limitations of TLIF include the significant muscle retraction and dissection, which can lead to postoperative pain, and delayed rehabilitation and impaired long term spinal motion [18]. Although we have listed the benefits here, and this is the authors’ preferred fusion technique, there is no evidence of any benefit of TLIF over other fusion techniques in long term studies of clinical symptoms and fusion rates.
The present study examines the experience of a two surgeon series with an extended TLIF for degenerative spinal disease. This technique is in contrast to the traditional TLIF, previously described by Hackenberg et al. and others [12], [30], [22], where the access to the intervertebral space is gained by unilateral facet joint resection. The traditional TLIF technique utilises a more minimal decompression than the extended TLIF described herein.
Section snippets
Methods
This is a retrospective study of 57 patients with extended TLIF, performed by the authors from February 2011 to January 2014. All patients had pre- and postoperative CT scans of the affected spinal area. The American Spinal Injury Association (ASIA) impairment score was used to document neurological function. The visual analog scale (VAS) was used to assess the level of pain before and after surgery. Pain was subclassified into severe (VAS 7–10), moderate (VAS 5–6) and mild (VAS 0–4). The Cobb
Clinical data
In total, 57 patients were included in this study, 19 men and 38 women. The mean age of the patients was 62.86 years (range: 25–82). The mean body mass index (BMI) for all patients was 30.31 kg/m2 (range: 20–51), for the men it was 28.46 kg/m2 and for the women 31.16 kg/m2. Two patients had emergency surgery, one for an acute foot drop (Patient 35), and another due to cauda equina syndrome (Patient 47). The remaining 55 had elective procedures, of which 49 patients (86%) had spondylolisthesis as
Discussion
After its first description by Harms et al. in the early 1980s [11], TLIF increased in popularity after further work by Harms et al. in the later part of the twentieth century [12]. The outcomes of the Swedish lumbar spine study demonstrated for the first time that lumbar fusion was significantly more effective than conservative treatment for low back pain [19], allowing lumbar fusion and TLIF to become the standard of care. The technique was initially developed with the view to achieve a
Conclusion
The present study is limited by its retrospective nature and relatively small patient population. Nevertheless, it demonstrated that bilateral decompression as part of a TLIF procedure is a safe and effective alternative to the traditional TLIF, which utilises a unilateral window through the facet joint to access the disc space. With this approach, pain, neurological status and spinal deformity were likely to improve after surgery. Future prospective and randomised studies should further define
Conflicts of Interest/Disclosures
The authors declare that they have no financial or other conflicts of interest in relation to this research and its publication.
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