Long-term clinical outcome of two revision strategies for failed total disc replacements

ALIF vs. posterior fusion for lumbar degenerative disease: comparable efficacy but elevated risk of severe complications-a systematic review and meta-analysis

BACKGROUND

Over the past years, there has been an upward trend in the total number of spinal fusion procedures worldwide. There are many different strategies to perform the lumbar fusion, each with some advantages. Hospital charges for lumbar spinal surgeries also have increased significantly, with great variation in the costs and recommendations of different surgical procedures. There has also been a trend increase in the rate of the use of interbody fusion implants compared to that of traditional decompression surgery, even though the former is known to incur higher costs. Access through the anterior route gained many followers after studies on sagittal balance, and its indication has also increased worldwide. However, this technique presents different patterns of complications from those observed in traditional posterior approaches.

OBJECTIVES

This study aims to determine the safety and efficacy of surgery in managing patients with symptomatic lumbar degenerative diseases by comparing the effectiveness of posterior and anterior approach techniques to treat this condition on patient-related outcomes. We also aimed to investigate the safety of these surgical interventions by including perioperative complication data.

METHODS

A systematic search of multiple online databases was conducted up to August 2024 to identify randomized controlled trials (RCTs) and other high-quality retrospective studies comparing outcomes of anterior lumbar interbody fusion (ALIF) versus posterior fusion techniques (PLF, PLIF, TLIF) in the treatment of degenerative lumbar diseases. The primary outcomes assessed included the Oswestry Disability Index, Visual Analogue Scale, and overall clinical improvement. Secondary outcomes encompassed complications such as mortality, infections, gastrointestinal complications, deep vein thrombosis (DVT), surgical site infections, and the need for blood transfusions, as well as length of hospital stay and operative duration. Pooled effect estimates were calculated and presented as mean differences (MD) with 95% confidence intervals (CI) at the two-year follow-up.

RESULTS

Regarding VAS and ODI, anterior and posterior approaches were similar in analyzing five RCTs. Including retrospective studies, we also found that the length of hospital stay and duration of surgery were comparable between the two approaches. Anterior approaches had a lower rate of patients requiring blood transfusions OR 0,69[0.60,0,80]. Anterior approaches showed higher rates of mortality (0,21%) OR1,33[1.10,1.62], deep vein thrombosis (0,65%) 1.73 [1.35, 2.20], and gastrointestinal complications (4,9%) OR 2.19 [1.73, 2.78].

CONCLUSION

Clinical outcomes measured by VAS and ODI were comparable between anterior and posterior approaches, demonstrating similar efficacy in treating lumbar degenerative diseases. However, the safety profiles varied significantly. Anterior approaches carried higher rates of severe complications, including mortality, DVT, and gastrointestinal events, while posterior techniques were linked to increased blood transfusion needs. Given the elevated risk of severe complications with ALIF, posterior approaches should be prioritized as the first-line option for lumbar degenerative disease.

Subsidence after total lumbar disc replacement is predictable and related to clinical outcome

Purpose

As yet, there are no studies describing a relationship between radiographic subsidence after lumbar total disc replacement (TDR) and patient symptoms. To investigate if subsidence, in terms of penetrated bone volume or angular rotation over time (ΔPBV and ΔAR), is related to clinical outcome. To assess if subsidence can be predicted by position implant asymmetry (IA) or relative size of the TDR, areal undersizing index (AUI) on direct post-operative radiographs.

Methods

Retrospective cohort study consists of 209 consecutive patients with lumbar TDR for degenerative disc disease. A three-dimensional graphical representation of the implant in relation to the bony endplates was created on conventional radiographs. Consequently, the PBV, AR, IA and AUI were calculated, direct post-operative (DPO) and at last follow-up (LFU). For clinical evaluation, patients with substantial pain (VAS ≥ 50) and malfunction (ODI ≥ 40) were considered failures.

Results

At a mean follow-up of 16.7 years, 152 patients (73%) were available for analysis. In 32 patients, revision by spinal fusion had been performed. Both ΔAR (4.33° vs. 1.83°, p = 0.019) and ΔPBV (1448.4 mm3 vs. 747.3 mm3, p = 0.003) were significantly higher in the failure-compared to the success-group. Using ROC curves, thresholds for symptomatic subsidence were defined as ΔPBV ≥ 829 mm3 or PBV-LFU ≥ 1223 mm3 [area under the curve (AUC) 0.723, p = 0.003 and 0.724, p = 0.005, respectively]. Associations between symptomatic subsidence and AUI-DPO ≥ 0.50 (AUC 0.750, p = 0.002) and AR-DPO ≥ 3.95° (AUC 0.690, p = 0.022) were found.

Conclusion

Subsidence of a TDR is associated with a worse clinical outcome. The occurrence of subsidence is higher in case of incorrect placement or shape mismatch.