226 - Risk Factors Affecting Length of Stay after MIS TLIF...

#226 Risk Factors Affecting Length of Stay after MIS TLIF

MIS Techniques and Outcomes

Poster Presented by: F. Chan


F.J. Chan (1)
A.D. Sharan (2)

(1) Albert Einstein College of Medicine, Bronx, NY, USA
(2) Albert Einstein College of Medicine, Orthopedic Spine Service, Bronx, NY, USA


Summary of Background Data: The impact of patient-related comorbidities, risk factors, and social variables on length of stay (LOS) in patients undergoing Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF) has not been well defined. Patients with increased LOS would benefit from pre-operative counseling and augmented level of perioperative care.

Objective: To identify factors that affect postoperative LOS after MIS TLIF and to develop a statistical model to predict variations in LOS.

Study Design: Retrospective review.

Methods: The operative report and patient's charts of one surgeon's first (61) MIS TLIF cases were evaluated for LOS and 14 patient risk factors. These included age, sex, social support, pre-operative hemoglobin, grade of spondylolisthesis, operating time, estimated blood loss (EBL), complications, smoking status, number of medical problems, body mass index, prior lumbar surgeries, time to physical therapy, and point in learning curve of the surgeon. The impact of the different risk factors on LOS was determined via correlation test for continuous variable and paired t-test for categorical variables. Risk factors found to be significantly correlated with LOS (p < 0.05) were used to build a statistical model using a forward stepwise linear regression.

Results: The medical records of 61 patients were evaluated. Risk factors associated with decreased LOS in decreasing order of significance were shorter incision to closure time (p = 0.001), lower EBL (p = 0.001), later point on the learning curve of the surgeon (p = 0.002), greater number of days after performing the first MIS TLIF by the surgeon (p = 0.004), lower BMI (p = 0.005), shorter total OR time (p = 0.016), being married or living with a significant other (p = 0.02), and having a prior lumbar surgery (p = 0.04). Regression analysis showed a high correlation of LOS with these variables (r = 0.68). Factors that did not significantly affect LOS were age, sex, pre-operative hemoglobin, grade of spondylolisthesis, occurrence of complications, smoking history, number of medical problems, and time to physical therapy.

Conclusions: Various factors are significantly associated with LOS after MIS TLIF. Appropriate prevention and management of perioperative factors could decrease LOS. The model described here represents an appropriate way of studying LOS variation after MIS TLIF.

Keywords: Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF), Risk factors, Length of stay.