#89 Factors Affecting Length of Stay Following Elective Posterior Lumbar Fusion: A Multivariable Analysis

Oral Posters: Quality of Spine Care

Presented by: M. Fu


J.A. Gruskay (1)
M. Fu (1)
D.D. Bohl (1)
M.L. Webb (1)
J.N. Grauer (1)

(1) Yale University School of Medicine, Department of Orthopedics and Rehabilitation, New Haven, CT, USA


Aims: Elective posterior lumbar fusion is a common surgical procedure, but reported length of hospital stay is variable (usually 3-7 days). To facilitate setting of realistic expectations and considering the significant costs of hospitalization, it would be ideal to have a clear understanding of the variables affecting length of stay (LOS) for this surgery. The effect of individual or select few factors on LOS has previously been evaluated. However, multivariate analysis using LOS as a dependent variable in order to separate potentially confounding variables has not been performed.

Methods: The charts of 103 patients undergoing elective, open 1-3 level posterior lumbar instrumented fusion (with or without decompression) by the orthopedic spine service at our institution between January 2010 and June 2012 were reviewed. LOS was determined from the date of surgery to the date of discharge.

Preoperative factors (patient demographics, previous surgery, levels instrumented, American Society of Anesthesiologists (ASA) score, and major medical comorbidities including diabetes, hypertension, malignancy, pulmonary disease or heart disease); intraoperative factors (complications, drain placement, estimated blood loss, blood transfusion, fluids administered, operating room time, and surgery time); and postoperative factors (drain removal, blood transfusion, complications, and discharge destination) were collected and analyzed with multivariable stepwise regression to determine predictors of LOS. “Postoperative complications” was excluded as an independent variable from the regression analysis because of its close relationship with LOS.

Results: Average LOS was 3.6 ± 1.8 days (mean+SD) with the range 0-12 days. Of this cohort, 79% (81 of 103) had a stay of four days or less. The only preoperative variables associated with increased LOS in the multivariable model were age (p = 0.038) and ASA score (p = 0.001). History of heart disease (p= 0.005) was significantly associated with a shorter hospital stay.

Intraoperative complications included six dural tears and one pedicle fracture. No intraoperative factors were found to be associated with a longer LOS.

Postoperative complications occurred in 32% of patients (33 of 103). Common complications included: anemia requiring transfusion(11), altered mental status (8), pneumonia (4), hardware complications requiring re-operation(3). Only one serious complication, renal failure, occurred. Average LOS for patients with a post-op complication was 5.1 ± 2.3 days vs. 2.9 ± 0.9 days for patients with no complication (p < 0.001). Discharge to a sub-acute or nursing facility was significantly associated with increased length of stay but cause and effect are difficult to separate (p < 0.001).

Conclusion: Patients that are older and have widespread systemic disease (increased ASA score) tend to stay in the hospital longer after elective, open spinal fusion. Contrary to our expectations, no single comorbidity was predictive of longer hospital stays. Heart disease was associated with a shorter length of stay, but this may have been due to a more extensive preoperative workup and closer medical management in hospital. Intraoperative events did not affect LOS, however postoperative events did. This data should prove useful for counseling patients and setting expectations of patients and health care teams.