The effect of minimally invasive posterior cervical approaches versus open anterior approaches on neck pain and disability

Study limitations

This analysis is a small retrospective analysis from a single surgeon's experience and suffers from all the traditional shortcomings of such studies. The cohort is nonrandomized, includes patients with both radiculopathy and myelopathy, and has incomplete follow-up and incomplete patient-derived outcome data. Despite these limitations, the study does use appropriate patient-derived outcome measures as recommended by evidence-based reviews⁴ and attempts to address a deficiency within the literature by comparing outcomes for patients having 2 different surgical approaches to their cervical spine pathology.^1–3 At baseline, the groups were well matched especially with respect to depression, which may have a significant effect on patient reported outcome.⁵

Does fusion help improve neck pain?

Many surgeons suggest that patients with myelopathy or radiculopathy and significant axial pain should be treated with an anterior interbody fusion, because a posterior decompression alone may exacerbate the patients’ neck pain, yet there is little evidence-based literature on which to base this suggestion. Indeed, in a follow-up to the original article by Smith and Robinson,⁶ it was noted, “There was no clear correlation after operation between absence of fusion at the interspaces and the clinical result.”⁷ The foundation for this suggestion is likely based on expert opinion or studies with a low level of evidence^{3, 8} rather than adequate analysis of clinical outcomes. Recent evidence-based reviews have provided no evidence to support or refute this suggestion. The reviews also note a paucity of comparative outcomes data,^1–3 especially given the number of cases performed each year in the United States. In our study no patient underwent surgery for axial complaints alone, and in all cases the patient manifested a neurologic concern as the indication for surgery.

This study suggests that a minimally invasive approach that largely preserves muscular and ligamentous attachments may result in similar clinical outcomes to an open anterior cervical approach that uses interbody fusion and instrumentation. Accordingly, our results suggest the need for further comparative effectiveness study. Indeed, we are in the process of extending our observations and collecting hospital resource use data to further address the question of comparative effectiveness.

Several studies have shown the effectiveness of a minimally invasive approach to posterior foraminotomy in providing relief of radiculopathy.^{9, 10} One study has compared the effectiveness of a minimally invasive approach for posterior foraminotomy with an open approach.¹⁰ Using nonvalidated outcome measures, the authors suggested equivalent outcomes. Thus it appears that a minimally invasive approach to posterior cervical foraminotomy can provide relief from cervical radiculopathy.

Few studies have provided comparative data between an anterior cervical approach and a posterior cervical approach for the treatment of degenerative cervical spine disease. The 2 studies that have provided data for a comparison between anterior and posterior cervical surgery did not use a minimally invasive approach to foraminotomy, did not use validated outcome tools, and accordingly, were thought to represent class III data.^{8, 11} Our study, though retrospective, does use validated outcome tools and does make an attempt to compare 2 commonly applied surgical approaches in terms of their effect on neck disability and pain.

Future implications

No surgical approach can replace sound clinical diagnosis and surgical decision making. Indeed, it is unlikely that the technical factors of surgery for cervical radiculopathy or myelopathy would contribute to clinical outcome more than the surgical decision-making process. Despite this caution, there is mounting evidence to suggest that minimally invasive surgery may have advantages over an open surgical alternative. These advantages may include a lower risk of infection,^12–14 a lower risk of symptomatic cerebrospinal fluid leak, a lower risk of new perioperative neurologic deficit,¹⁵ and a lower overall complication rate.¹⁶ These potential advantages do not necessarily guarantee similar short- or long-term clinical outcomes, and to date, there is little evidence to support the use of a minimally invasive approach over an open approach. Unfortunately, the approach recommended to the patient may rest more upon the comfort level of the treating surgeon or, more cynically, the financial motive of the treating surgeon, rather than clinical outcome data. Ideally, the decision should not be limited by either the surgeon's expertise or the associated reimbursement. The decision should be directed at affording the patient the best possible clinical outcome. If, however, 2 procedures can provide similar clinical outcomes, then the relative healthcare resource utilization and cost should be taken into account. At this juncture, the comparative effectiveness of the 2 techniques should be taken into account and the more effective technique applied as often as appropriate, thus also affording a potential societal benefit.