Factors associated with length of stay after single-level posterior thoracolumbar instrumented fusion primarily for degenerative spondylolisthesis

BACKGROUND: The postoperative length of stay (LOS) is an important prognostic indicator for patients undergoing instrumented spinal fusion surgery. Increased LOS can be associated with higher infection rates, higher incidence of venous thromboembolisms, and a greater frequency of hospital-acquired delirium. The day of surgery and early postoperative mobilization following single-level posterior thoracolumbar stabilizations may impact the LOS. In this study, we evaluated the effects of weekday (Monday–Thursday) versus weekend (Friday–Sunday) surgery and postoperative rehabilitation services on LOS following primarily transforaminal lumbar interbody fusion (TLIF) for degenerative spondylolisthesis (DS). METHODS: In this single-institution retrospective chart review, we identified 198 adults who received a one-level thoracolumbar instrumented fusion through a posterior only approach (2017–2019). The majority of these patients underwent TLIF for DS. A zero truncated negative binomial model was used for predictors of the primary outcome of LOS (weekday of surgery, duration of operation, first or repeat surgery, and physical therapy/ occupational therapy [PT/OT] evaluation). Covariates were sex, age, and body mass index. RESULTS: We found that operative duration, repeat surgery, and in-hospital PT/OT all significantly increased the LOS (P < 0.05). Furthermore, those undergoing weekday surgery (Monday–Thursday) had 1.29 times longer LOS than those on the weekend (Friday–Sunday), but this did not reach statistical significance (P = 0.09). CONCLUSION: In our patient sample, duration, repeat surgery, and in-hospital PT/OT increased the LOS following primarily TLIF for DS. The increased LOS in these cases is likely due to higher overall disease burden and case complexity. In addition, those patients with a greater likelihood of extended recovery and ongoing neurologic deficits are more likely to have PT/OT evaluations. Notably, LOS was not significantly impacted by the day of surgery at our institution.