Analysing the clinical relevance and impact of subsidence seen with standalone cages for cervical disc surgeries – A study of fusion rates in 118 patients

Author(s): Vishnu Vikraman Nair, Vishal Kundnani, Mukul Jain, Sunil Shamjibhai Chodavadiya, Abhijit Shetty, Jenil Patel, Nikhil Dewnany

Background and Aim:

The objective of this study is to examine the short and long term impact of subsidence after anterior cervical discectomy and fusion for compressive cervical disc disease, utilizing solely non-locking stand-alone titanium cage and to analyze the fusion rates.

Methods:

The single-center retrospective study included one and two-level Anterior cervical discectomy and fusion (ACDF) cases from July 2014 to June 2019. Minimum 2-year follow-up was included and titanium cage with autologous bone graft was used. Interbody height (IBH), subsidence and fusion rates were analysed at follow up. Clinically, VAS score for neck and arm, mJOA score for myelopathy, C2-C7 cobb angle for lordosis improvement were analyzed.

Results:

A sample of 118 patients, was subjected to analysis. The fusion rate was observed to be 96.6%. Eleven instances of subsidence were observed at the 3-month follow-up (p= 0.89). All 11 patients with subsidence had excellent/good functional outcomes on analyzing Odom’s criteria. The study observed a noteworthy enhancement in the (VAS) for neck and arm pain, as well as in the (mJOA) score among patients with myelopathy, with a statistical significance of p<0.05. There was significant reduction in IBH in the subsidence group in comparison to non-subsidence group. Segmental kyphosis angles were also seen to be higher in the subsidence group(p<0.05)

Conclusion:

According to our study, the subsidence observed did not have a significant clinical impact on outcome scores or patient satisfaction. The utilisation of a stand-alone cage devoid of screw or plate instrumentation has demonstrated favourable long-term outcomes with nearly complete fusion rates. Furthermore, there is no significant difference in outcomes between the subsidence and non-subsidence groups.