Predictors of Extended Hospital Stay after Cervical Disc replacement or Anterior Cervical Discectomy and Fusion: Results from 1,004 Patients in an FDA Trial
Authors: Greenberg Aaron , Mummaneni Praveen , Yoon S. Tim 
Published: April 2016

Introduction

Extended hospital stay after surgery is costly to the healthcare system and can be distressing to the patient and family. While many studies have shown that the type of surgery influences length of hospital stay, there is a paucity of data on factors that extend hospital stay after single level anterior cervical surgery. We used the data from a large series of patients involved in two FDA Trials comparing one level cervical disc replacement to one level ACDF to identify factors that contribute to prolonged hospital stay. Materials/Methods: Data from 1004 patients involved in the Investigational arm ( n = 518) and Control arm ( n = 486) of the Brian/Prestige CDR Trial were analyzed. The dependent variable of this analysis was LOS (length of hospital stay). The independent variables analyzed for their affect on LOS after CDR/ACDF included the following: Demographic characteristics, Preoperative efficacy measurements (NDI, SF-36, etc.) Preoperative medical conditions and medication, Preoperative Neurologic Status (motor function, Nurick-Gait, etc.) and Intraoperative factors (Operative time, EBL, etc.) Subjects with a LOS (defined as date of discharge - date of initial surgery) of zero days (same day discharge) or one day (over-night discharge) were compared with those with a length of stay greater than one day.

Results

An initial logistic regression analysis was performed. Treatment group was found not to be a significant factor in length of hospital stay between CDR and ACDF. Because of this, a second logistic regression model was created using all-comers data and included eight independent variables (Race, Tobacco Used, Weak Narcotic Medications, Arm Pain Score, SF-36 MCS, Preoperative Sensory, Gait and Operative Time) identified to be significant (p-value < 0.05) in the preliminary analysis. A total of 912 (90.84%) patients had a Length of stay less than or equal to one day (one midnight) and 92 patients (9.16%) had an extended length of stay greater than one day (two or more midnights). Three variables were determined to have a significant affect on increasing the length of hospital stay: Weak Narcotic Medications Usage (P=.021, O.R. 1.72), Nurick-Gait (P=.019, O.R. 1.796), and Operative Time. In particular, Operative Time is was found to be highly significant with p-value < 0.0001. With a one-hour increase in the operative time, the odds of longer hospital stay increase by 2.062. Comorbid factors such as Cardiac, DM, other diseases were found not to affect the hospital length of stay after CDR and ACDF.

Conclusion

We used the high quality data from a large cohort of patients involved in FDA trials and found Nurick-Gait, Operative Time, and History of Weak Narcotic Usage to be drivers of extended hospital stay. Importantly, we also found that there is no correlation between comorbidities such as Cardiac, DM, other diseases with length of hospital length of stay after CDR and ACDF. These data may be useful in preoperatively counseling patients, developing quality metrics for hospitals, and to help create financial models for cost/DRG reimbursement for single level anterior cervical surgery.