Evaluating the Incidence of Postoperative Fluid Collection with MRI After Posterior Cervical Decompression and Fusion and Lumbar Fusion Surgeries

Introduction: Postoperative fluid collections can be a common occurrence following spine surgery. When suspected, MRI is the preferred modality of diagnostic imaging. However, the presenting symptoms of patients that may contribute to findings of compressive fluid collections on MRI have yet to be elucidated. As such, the current study aimed to examine the relationship between presenting symptomatology and radiologic findings on MRI, as well as characterize subsequent management and outcomes.

Methods: Adult patients who underwent posterior cervical decompression and fusion (PCDF) or lumbar fusion at a tertiary care center from 2017-2022 and had an MRI within 14 days following surgery were retrospectively reviewed. Those undergoing surgery for trauma, tumor, infection, revision, or using anterior approaches were excluded. Demographic and surgical characteristics were collected. Outcomes of interest were indications for undergoing MRI stratified into numbness/pain and neurologic deficit/weakness; presence of fluid collection on MRI; surgical drain characteristics including time, number, and output; and subsequent treatment, symptomatic improvement, readmission within 2 weeks, surgical complications, and discharge disposition.

Results: A total of 58 patients who met inclusion criteria were included. Of these, 15 patients underwent MRI for numbness/pain while 43 underwent it for neurologic deficit/weakness. There were no differences between the groups with regards to demographic or surgical characteristics. The presence of fluid collection with or without neural compression; all surgical drain characteristics; incidence of operative versus nonoperative treatment, symptomatic improvement, 2-week readmission, and surgical complications; and discharge disposition were similar between groups. When the cohort was stratified based on the presence of fluid collection, as well as subgroup analysis performed on patients with evidence of fluid collection with neural compression on MRI, all outcomes of interest continued to be comparable between groups.

Conclusion : The current study found no association between presenting symptomatology and patients’ demographic or surgical characteristics. Symptomatology was also not associated with fluid collection findings on MRI, type of treatment utilized, or rates of improvement and subsequent outcomes. Further research should focus on identifying other, more granular aspects of patient presentation that may indicate the need to evaluate for postoperative fluid collection, and possible return to the OR.