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Post-operative hematoma (POH) following anterior cervical discectomy (ACDF) is uncommon . Although rare, POH is recognized as a potentially catastrophic post-operative complication . There is limited information as to who is vulnerable . From a large database, the authors sought to identify common modifiable and non-modifiable risk factors for developing POH and its associated clinical outcomes.

Materials and Methods

The Michigan Spine Surgery Improvement Collaborative (MSSIC) is a statewide quality improvement initiative . ACDF cases in MSSIC registry from 2014-2018 were identified . Patients who developed POH (POH) were compared to those who did not (non-POH) . Chi-square and t-test analyses were done to compare the two groups in terms of demographics, surgical characteristics, patient reported outcomes (baseline and postoperative PROMIS-PF score), and other postoperative symptoms or complications . All analyses were performed by using SAS 9 .4


Incidence of POH is low . Of the 9,958 cases, it only occurred in 114 cases (1 .1%) . POH was associated with male gender (1 .6% vs 0 .7%, p < .001), advanced age (age 59±11 vs 55±11, p < .001), baseline use of anticoagulation (2 .3% vs 1 .1%, p= .031), previous spine surgery (1 .6% vs 0 .9%, p= .005) and inpatient procedures (1 .3% vs 0 .7%, p= .024) . POH was also associated with which cervical levels were operated (p< .001), with the highest rates observed in surgeries involving C3-C6 (3 .6%) and C3-C5 (3 .8%) while the lowest in surgeries involving C5 to C7 (0 .5%) . Smoking, multi-level surgery, corpectomy and drain use were not associated with hematoma (p> .10 for all) . Reports of dysphagia (6 .9% vs 29 .8%, p < .001), prolonged hoarseness (2 .4% vs 9 .7%, p < .001) and weakness (5% vs 10 .5%, p= .007) were common in the POH group . No significant differences in PROMIS outcomes were observed between POH and the non-POH groups at baseline (p= .232) and post-operatively at 90 days, 1 year, and 2 years (p> .05)


POH is rare . Intrinsic or non-modifiable risk factors identified were gender, age, baseline use of anticoagulation, prior surgery and anatomical exposure . Dysphagia, prolonged hoarseness and weakness were common in the POH group . Discussion: Although intrinsic factors cannot be eliminated, surgical risk factors can be minimized . Our large database review revealed procedures involving C3-C5 and C3-C6 had the highest rate of hematoma compared to more caudal surgeries . Difficulties with exposure as well as vascular anatomy in the upper cervical spine, the cricothyroid arteries bilaterally (Figure 1), could explain this finding . Thorough visual inspection to ensure hemostasis is obtained prior to closure is critical . POH, if left unrecognized put patients at significant risk for this life-threatening postoperative complication . Effective screening targeted at high-risk patients may help in prevention and early detection

Publication Date





The Cervical Research Society - 51st Annual Meeting, Las Vegas, Nevada, November 29-December 2, 2023.

A MSSIC Study Reveals Non- Modifiable Risk Factors Were Associated with Post-Operative Hematoma following ACDF

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