Comparison between gravity drainage group and suction drainage group after cervical laminoplasty: a retrospective STROBE-compliant cohort study

Objectives A retrospective study was conducted to compare gravity drainage and suction drainage after cervical laminoplasty. Patients and methods A total of 375 patients who underwent laminoplasty between January 2011 and December 2015 were engaged in this analysis. We investigated the patients' basic characteristics, drainage characteristics and postoperative complications. Results During the initial 24 h after laminoplasty, the drainage volume in the suction drainage group was 177.31 +/- 92.02 mL, and the drainage volume in the gravity drainage group was 133.33 +/- 92.40 mL. The drainage volume showed significant difference (p < 0.01). The total drainage volume was 357.49 +/- 195.16 mL and 250.16 +/- 27.44 mL in the suction drainage group and gravity drainage group, respectively. The total drainage volume between the two groups was statistically different (p = 0.03). The postoperative Hb was significantly different between the gravity group and suction group on the first day after the operation (108.37 +/- 23.92 mL vs. 87.32 +/- 21.53 mL, p = 0.02). The number of patients required blood transfusion was significantly different between the two groups as well (p = 0.04). Two cases had symptomatic epidural hematomas (SEH) after laminoplaty. However, the occurrence of SEH among the two groups was not different significantly. Twelve patients had surgical site infection (SSI). Of these 12, nine had applied gravity drainage and three suction drainage. The rate of SSI was similar between the two groups (p = 0.71). Conclusion The initial 24 h' drainage volume and the total drainage volume increased significantly in the suction drainage group. The postoperative Hb was lower in the suction group than the gravity drainage group the first postoperative day. More patients needed blood transfusion if suction drainage was performed. The application of suction drainage cannot decrease the incidence of SSI and SEH after laminoplasty. Gravity drainage is recommended for laminoplasty.