Effectiveness of Gelatin-Thrombin Matrix Sealants (Floseal®) on Postoperative Spinal Epidural Hematoma during Single-Level Lumbar Decompression Using Biportal Endoscopic Spine Surgery: Clinical and Magnetic Resonance Image Study

Table 2

Incidence of PSEH after BESS by grading system and the incidence of revision surgery caused by PSEH. (PSEH: postoperative spinal epidural hematoma, BESS: biportal endoscopic spine surgery).

	Total patients	Group A; (56.8%)	Group B; (43.2%)
Non-PSEH (Grade 0)	169 patients (79.1%)	86 patients (73.5%)	77 patients (86.5%)
PSEH (Grades I~IV)	43 patients (21.9%)
Grade I (canal encroachment 0~25%)	19 patients (9.2%)	10 patients (8.5%)	9 patients (10.1%)
Grade II (canal encroachment 50~75%)	19 patients (9.2%)	16 patients (13.7%)	3 patients (3.4%)
Grade III (canal encroachment 50~75%)	5 patients (2.4%)	5 patients (4.3%)	0 patients (0.0%)
Grade IV (canal encroachment 50~75%)	0 patients (0%)	0 patients (0%)	0 patients (0.0%)
Revision due to PSEH	2 patients (0.9%)	2 patients (1.7%)	0 patients (0.0%)