Objective: Outpatient spine surgery could reduce hospital costs and improve patient outcomes. Outpatient lateral lumbar interbody fusion (LLIF) can be performed for select patients. This study identified and compared the demographic, clinical, and surgical characteristics of patients who underwent outpatient versus inpatient single-level LLIF.
Methods: A retrospective review was conducted of a prospectively collected database of patients who underwent first-time single-level LLIF at a single institution performed by the same surgeon from January 1, 2017, through December 31, 2022. Demographic characteristics, including age, sex, BMI, and medical comorbidities, were collected. Surgical factors, such as level of surgery, operative duration, and estimated blood loss, were also collected. Length of stay and 30-day readmission were the primary outcomes of interest. Patients discharged on the day of surgery or the following day were considered to be in the outpatient group. ANOVA and chi-square tests were performed to compare continuous and categorical variables, respectively. Univariate logistic regression was used to examine the correlation between baseline demographic and surgical variables and outpatient surgery. If a variable significantly correlated with outpatient surgery on univariate analysis, it was subsequently used in multivariate logistic regression.
Results: A total of 107 patients underwent first-time single-level LLIF, and 48 (44.9%) did not have posterior instrumentation. Fifty-three (49.5%) patients were women. The median age and BMI were 66.3 years and 28.9, respectively. The mean length of stay was 1 day (range 0-4 days), with 71 (66.4%) of 107 single-level LLIFs managed on an outpatient basis. There were no readmissions within 30 days. Patients in the outpatient group were more likely than patients in the inpatient group to be male (59% [42/71] vs 25% [9/36], p = 0.002), have a low LACE (risk criteria based on length of stay, acuity of the admission, comorbidity of the patient, and emergency department use within 6 months before admission) readmission index (63% [45/71] vs 28% [10/36], p < 0.001), and have a stand-alone construct (62% [44/71] vs 11% [4/36], p < 0.001). The outpatient cohort also had a shorter mean operative duration (104.4 vs 175.5 minutes, p < 0.001) and lower mean estimated blood loss (20 vs 100 mL, p < 0.001). There was no difference in age between the groups. Factors that remained significant on multivariate logistic regression were male sex (OR 0.14, 95% CI 0.04-0.53; p = 0.004), lower LACE readmission index (OR 0.06, 95% CI 0.02-0.25; p < 0.001), and stand-alone construct (OR 8.17, 95% CI 1.49-44.74; p = 0.02).
Conclusions: Multiple baseline and surgical characteristics were more common in the outpatient setting. With appropriate patient selection, single-level LLIF can be achieved on an outpatient basis.
Keywords: lateral approach; lumbar; minimally invasive spinal surgery.