Answer to the Letter to the Editor of C. Birkenmaier concerning "Minimally invasive surgery procedure in isthmic spondylolisthesis" by F. C. Tamburrelli et al. [Eur Spine J (2018): doi:10.1007/s00586-018-5627-8]

Lumbar interbody fusion using oblique (OLIF) and lateral (LLIF) approaches for degenerative spine disorders: a meta-analysis of the comparative studies

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

Historically, posterior approaches to the lumbar spine have allowed surgeons to manage degenerative conditions affecting the lumbar spine. However, spinal muscles injury, post-surgical vertebral instability, cerebrospinal fluid (CSF) leakage, and failed back surgery syndrome (FBSS) represent severe complications that may occur after these surgeries. Lumbar interbody fusion using anterior (ALIF), oblique (OLIF), or lateral (LLIF) approaches may represent valuable surgical alternatives, in case fusion is indicated on single or multiple levels.

METHODS

The present study is a systematic review, conducted according to the PRISMA statement, of comparative studies on OLIF, and LLIF for degenerative spine disorders, and a meta-analysis of their clinical-radiological outcomes and complications.

RESULTS

After screening 1472 papers on PubMed, Scopus, and Cochrane Library, only 3 papers were included in the present study. 318 patients were included for data meta-analysis, 128 in OLIF group, and 190 in LLIF group. There were no significative differences in terms of surgical (intraoperative blood loss and surgical duration) and clinical (VAS-back, VAS-leg, and ODI scores) outcomes, or fusion rates at last follow-up (> 2 years). Significantly higher rates of abdominal complications, system failure, and vascular injuries were recorded in the OLIF group. Conversely, postoperative neurological symptoms and psoas weakness were significatively more common in LLIF group.

CONCLUSIONS

The meta-analysis suggests that OLIF and LLIF are both effective for lumbar degenerative disorders, although each of them presents specific complications and this should represent a relevant element in the surgical planning.

Radiological evaluation of fusion patterns after lateral lumbar interbody fusion: institutional case series

INTRODUCTION

There is no consensus on how to evaluate segmental fusion after lateral lumbar interbody fusion (LLIF). Bone bridges (BB) between two contiguous vertebra are reported as pathognomonic criteria for anterior fusion. However, to the best of our knowledge, there are no radiological investigations on zygapophyseal joints (ZJ) status after LLIF. The aim of this radiological study was to investigate the different fusion patterns after LLIF.

MATERIALS AND METHODS

This is a retrospective single-centre radiological study. Patients who underwent LLIF and posterior percutaneous screw fixation for degenerative spondylolisthesis, on a single lumbar level, were considered for eligibility. Complete radiological data and a minimum follow-up of 1 year were the inclusion criteria. Intervertebral BB were investigated for evaluating anterior fusion and ZJ ankylotic degeneration was evaluated according Pathria et al., as a matter of proof of posterior fusion and segmental immobilization.

RESULTS

Seventy-four patients were finally included in the present study. Twelve months after surgery, intervertebral BB were recognized in 58 segments (78.3%), whereas ZJ Pathria grade was I in 8 (10.8%) patients, II in 15 (20.3%) and III in 51 (68.9%) that were considered posteriorly fused. The overlapping rate between anteriorly and posteriorly fused segments was 72.4% (42 segments), whereas 10 (13.5%) did not achieve any fusion, anterior or posterior, and 6 (8.1%) were posteriorly fused only.

CONCLUSIONS

Our results seem to suggest that anterior fusion is not sufficient to achieve segmental immobilization. Further properly designed investigations are needed to investigate eventual clinical-radiological correlations.