Comparison of Cost and Perioperative Outcome Profiles for Primary and Revision Posterior Cervical Fusion Procedures

Michael L. Martini, PhD; Rebecca B. Baron, BS; Jonathan S. Gal, MD; Sean N. Neifert, BS; William H. Shuman, BA; Alexander J. Schupper, MD; Emily K. Chapman, BS; Ian T. McNeill, MD; Jeremy Steinberger, MD; John M. Caridi, MD

Disclosures

Spine. 2021;46(19):1295-1301. 

In This Article

Discussion

This study sought to compare the clinical outcomes of patients undergoing primary PCDF to those undergoing revision procedures at a single, large academic medical center in the United States. Despite the increasing prevalence of both primary and revision cervical procedures,[10] very few studies have examined the outcome profiles of revision cervical procedures in patients with degenerative conditions. To provide a more complete assessment of the outcome profiles in this patient population, primary and revision cervical cohorts were compared in terms of several outcome domains: perioperative medical complications, perioperative adverse outcomes, and cost and resource utilization outcomes.

Perioperative Medical Complications

Analysis of perioperative medical complications revealed that patients undergoing revision cervical fusions did not experience increased rates of any of the perioperative medical complications examined in this study. These included airway complications, bleeding complications, renal and cardiac complications, pneumonia, surgical site infections, sepsis, urinary tract infections, and durotomy (Table 2). Furthermore, while the overall rate of complications was higher in the revision cohort (21.6%) compared with the primary surgical cohort (17.8%), the difference in these rates was not statistically significant (P = 0.20). Multivariate analyses controlling for key demographic and perioperative variables confirmed these findings by showing that patients undergoing revision procedures did not have significantly increased odds of complication compared with patients undergoing primary fusion procedures (Table 3).

Previous studies examining revision spinal surgery have suggested an increased risk of poor postoperative outcomes in this population. For example, it has been thought that patients who have undergone prior spinal surgery may have relatively devascularized tissues at the surgical site which may impair postoperative wound healing and increase the risk of wound infections after subsequent operations.[15] In addition, scar tissue and dural adhesions from prior surgeries may increase the risk of an incidental durotomy occurring during revision procedures.[16–18] Very low rates of surgical site infections and incidental durotomies were observed in both the primary and revision cervical cohorts in the present study (Table 2). Of note, these rates reflect those of a recent retrospective review by Guerin et al[19] that explored the incidence of incidental durotomy and wound infections during spine surgery in over 1300 patients. Despite observing 51 dural tears in their study population (3.84%), Guerin et al[19] reported that only one of these occurrences was associated with a posterior cervical procedure. In addition, only two wound infections were noted across all patients.

The present study also aimed to investigate predictors of complications in both surgical cohorts. Multivariate analyses revealed that, although prior surgery status was not a significant predictor of complication risk, comorbidity burden was predictive. These results are in accordance with findings from previous studies in spine surgery,[20–24] which have demonstrated that patients cohorts with higher comorbidity burdens tended to face an increased risk of postoperative medical complications. One potential reason for these findings might be that patients with high comorbidity burdens may have a reduced physiological reserve, which may mean that they have a decreased ability to recover from the physiological demand of spinal surgery without the occurrence of certain medical complications. This concept has also been described in the setting of adverse postoperative outcomes in elderly patients;[25] however, age was not found to be a significant predictor of complications, despite well-described correlations between age and comorbidity burden.[26]

Perioperative Adverse Outcomes

Analysis of perioperative outcomes in this study revealed that, while patients undergoing revision cervical fusions had reduced odds of required ICU stays compared with patients in the primary surgery cohort, they had significantly higher odds of visiting the ED within 30 days of hospital discharge (Table 3). One potential reason for this outcome discrepancy might be that there is an underlying difference in the amount of postoperative pain experienced by revision surgery patients compared with primary surgery patients. Previous studies have demonstrated that patients with a history of prior cervical spine surgery have significantly reduced improvements in quality of life outcomes at 2-year follow up.[27] Given that pain is an oft-cited measure as well as one of the leading causes of ED visits and hospital readmissions, improved postoperative pain management protocols specifically designed for revision surgical patients could possibly prove valuable for reducing the rates of 30-day ED visits in this population. This hypothesis, however, was unable to be studied with primary data from the present study and these current recommendations remain speculative.

Cost and Resource Utilization Outcomes

Few studies in the literature have examined how costs for revision cervical procedures compare to the costs of the corresponding primary procedures. In this study, multivariate analyses of various cost differences between primary and revision cervical surgical cohorts demonstrated that the revision cohort experienced significantly higher direct costs of hospitalization compared with the primary cohort (Table 3). A similar analysis applied to other cost categories revealed that surgical costs were also significantly higher in the revision cohort, but not costs associated with laboratory, pharmacy, or nursing services. Only one other study in the literature has explored cost outcomes in patients undergoing revision cervical spine surgery,[28] concluding that costs did not differ significantly based on the etiology of the revision. That is consistent with our findings, which revealed a relatively weak association between preoperative diagnosis and direct cost in the study population. Conversely, prior surgery, male sex, comorbidity burden, EBL, surgical duration, and number of segments operated were all found to be significant predictors of direct cost in the study population. These results highlight the need for improved methods for patient selection in cervical spine surgery, perhaps with a greater focus on patient demographics, comorbidities, and whether the procedure in question is a revision surgery. This may help optimize patient outcomes, improve healthcare resource utilization, and reduce unnecessary costs in cervical spine surgery.

Limitations

There are several important study limitations that must be acknowledged. First, the retrospective design of this study makes it difficult to assess temporal relationships between variables. In addition, the single-institution nature of the data may mean the results reflect region- and institution-level differences, including preferences in patient management and surgical practice. While these structural differences may be difficult to control for in statistical analyses, they do contribute consistency in terms of how cases are managed and may reflect some of the intricacies of clinical practice that may not be captured in more controlled trial settings. In addition, the 30-day perioperative timeframe used in this study to examine perioperative events may have limited the detection of some of the adverse events that otherwise might have occurred at a later point. The dataset in this study also did not contain information regarding the nature of the perioperative ED admissions, which would have enabled more detailed analyses of this outcome. Finally, as with any retrospective nonrandomized study, uncontrolled confounders could introduce bias into the analysis.

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