Lumbar Fusion PROMs: Before and After WHO Declared COVID-19 a Pandemic
Authors: Patel Madhav R. , Jacob Kevin C. , Shah Vivek P. , Vanjani Nisheka N. , Pawlowski Hanna , Prabhu Michael C. , Singh Kern 
Published: June 2024

Background The World Health Organization (WHO) declared COVID-19 a pandemic on March 11th, 2020. Few studies have compared patient-reported outcome measures (PROMs) before and after this declaration among lumbar fusion recipients. Objective To compare PROMs and achievement of minimal clinically important difference (MCID) among lumbar fusion recipients before vs. after the arrival of the COVID-19 pandemic. Methods A single-surgeon retrospective registry was searched for patients who underwent single- or double-level lumbar interbody fusion (LIF) via anterior (ALIF), lateral (LLIF), or a minimally invasive transforaminal (MIS TLIF) approach. A cut-off day of surgery (March 11th, 2020) was used to divide patients into two groups: those receiving fusion from the cut-off date to October 2021 (19-month period), vs those receiving fusion between August 2018 and the cut-off date (19-month period). Patients not meeting this day of surgery criteria were excluded, along with those undergoing surgery for etiologies of infection, malignancy, or trauma. Demographic characteristics and perioperative variables were collected for each cohort, along with the following PROMs: Visual Analog Scale (VAS) back/leg, Oswestry Disability Index (ODI), Patient Health Questionnaire-9 (PHQ-9), and Patient Reported Outcome Measurement Information System physical function (PROMIS-PF) preoperatively and at 6-weeks, 12-weeks, 6-months, and 1-year following fusion. Demographic, perioperative and PROM characteristics were compared with Student’s t-test for independent samples (continuous) or chi-squared analyses (categorical). Multiple regression analysis was performed to evaluate the effect of pre-pandemic vs. pandemic status on mean PROMs, while accounting for baseline difference in type of fusion received. MCID achievement was determined by thresholds established in literature for delta PROMs, while intergroup comparison in rate of achievement was evaluated with chi-squared analysis. Results 180 subjects met inclusion criteria of this study, with 124 in the pre-pandemic cohort and 56 in the pandemic cohort. Mean age was 56.2 years, with most patients being non-obese (52.8%) and male (57.2%) (Table 1). Majority of patients presented with degenerative spondylolisthesis (48.3%), followed by isthmic spondylolisthesis (38.3%), recurrent herniated nucleus pulposus (15.0%), and degenerative scoliosis (14.4%), with no intercohort differences in spinal pathology. MIS TLIF was the most frequent procedure among included patients (36.1%), followed by LLIF (35.0%), and ALIF (28.9%). The pre–pandemic cohort had a significantly higher proportion of LLIF recipients, while the pandemic cohort had a significantly higher proportion of ALIF recipients (p=0.019). Most patients had single-level surgery (87.8%), with 12.2% receiving double-level fusion. No significant difference was observed in the number of operative levels among groups. Mean operative time was 148.4 minutes with mean estimated blood loss of 72.2 mL, with no difference in mean values between groups (Table 2). While the pre-pandemic cohort significantly improved for all VAS back, all VAS leg, ODI 12-weeks to 1-year, all PHQ-9, and PROMIS-PF 12-weeks to 1-year (p≤0.025, all), the pandemic cohort significantly improved for VAS back 6-weeks to 6-months, VAS leg 6-weeks, ODI 6-months, PHQ-9 6-months, and PROMIS-PF 12-weeks/6-months, only (p≤0.025, all). No significant differences were observed in mean PROMs at any timepoint. After multiple regression accounting for differences in the type of fusion procedure performed, PHQ at preoperative was significantly higher in the pre-pandemic cohort (p=0.019), but no other intercohort differences were observed (Table 3). MCID achievement across all PROMs did not significantly differ at any timepoint (Table 4). Conclusion Less lumbar procedures were performed in an equivalent time period of 19 months before and after the WHO announcement of COVID-19 as a pandemic on 3/11/20. While patients receiving fusion after this date experienced scattered statistically significant improvements across PROMs compared to pre-pandemic counterparts, mean PROM ratings and MCID achievement rates for pain, disability, depression, and physical health were generally equivalent. The COVID-19 pandemic is therefore unlikely to significantly alter clinical outcomes following lumbar fusion.