The utility of obtaining routine hematological laboratory values following an anterior cervical diskectomy and fusion.

STUDY
DESIGN: Retrospective analysis of a prospectively maintained database.
OBJECTIVE: To characterize the utility of obtaining routine postoperative laboratory studies after an anterior cervical diskectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: ACDF is typically associated with minimal blood loss and morbidity. However, at many institutions, postoperative laboratory studies are conducted routinely. This study aims to characterize the utility of these tests in the postoperative setting.
METHODS: A retrospective analysis of a prospectively maintained database of 332 patients who underwent an ACDF for degenerative cervical spine disease between 2007 and 2014 was performed. Patients with a concurrent corpectomy, posterior fusion, or revision procedure were excluded. Patient demographics, comorbidities, visual analogue scale scores, surgical and hospitalization parameters, complications, and transfusion volumes were assessed. The patient's postoperative laboratory studies were compared with preoperative values. Statistical analysis was performed with independent sample T tests for continuous variables and χ analysis for categorical data. An α level of less than 0.05 denoted statistical significance.
RESULTS: A total of 332 patients were included with a mean age of 51.1 ± 11.7 years. The overall mean procedural time, estimated blood loss, and length of stay were 60.0 ± 30.1 minutes, 69.4 ± 36.2 mL, and 40.2 ± 20.3 hours, respectively. Overall, 98.1% of patients demonstrated radiographical arthrodesis at 1 year. After a 1- or 2-level ACDF, the postoperative hemoglobin, hematocrit, blood urea nitrogen, sodium, and calcium levels significantly decreased, whereas glucose and chloride levels increased when compared with the preoperative values (P < 0.05). In addition, the 1-level ACDF cohort was also associated with reduced postoperative potassium level (P < 0.05). However, none of the patients required intraoperative or postoperative blood product transfusion or demonstrated evidence of postoperative anemia. Two patients (0.89%) required postoperative potassium replacement based upon laboratory values alone without clinical symptomatology. There were no complications that were related to the patient's hemodynamic status or fluid and electrolyte balance.
CONCLUSION: In the majority of cases after an ACDF, no action was taken n the basis of the patient's routine postoperative laboratory data. None of the patients required blood product transfusion, whereas only 0.89% (n = 2) required potassium replacement for laboratory anomalies without clinical symptomatology. These findings suggest that routine postoperative complete blood counts do not change postoperative management after an ACDF unless intraoperative bleeding is noted or the patient carries risk factors for postoperative hemorrhagic anemia. LEVEL OF EVIDENCE: 3.