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.

Extensive Spinal Epidural Abscesses Resolved with Minimally Invasive Surgery: Two Case Reports and Review of the Recent Literature.

PURPOSE: An extensive spinal epidural abscess is a rare condition and causes significant morbidity and mortality. Few authors have described this uncommon entity, which requires early diagnosis and optimal treatment to avoid devastating complications. The purpose of this study was to evaluate a minimally invasive technique for treatment of an extensive spinal epidural abscess by describing two cases. Furthermore, we conducted a review of the recent literature on the management of this rare condition. METHODS: We report two cases of spinal abscesses extending to the whole epidural space, successfully treated by use of a minimally invasive technique consisting of multilevel laminotomy and catheter irrigation to decompress and drain the epidural space. RESULTS: This technique is able to decompress the spinal cord, isolate the pathogen and evacuate the abscess. No complications, late spine deformity or dura penetration were observed in our patients. CONCLUSION: Urgent surgical decompression, in combination with long-term antibiotic treatment, is generally considered the treatment of choice for an extensive spinal epidural abscess. A minimally invasive technique can be very useful as a surgical option.