Most asymptomatic patients with chronic subdural hematoma (CSDH) are followed conservatively but can require surgical treatment if the hematoma expands. We conducted a retrospective evaluation of the effect of Gorei-san on CSDH. This study included patients treated between April 2013 and March 2015. In total, 289 patients were diagnosed with CSDH and 110 patients received conservative management. Finally, 39 patients who met the requirements were registered. We retrospectively examined the age, gender, medical history, hematoma thickness, clarity of sulci below hematomas, and midline shift of the patients. The primary outcome was the median surgery-free interval, and the secondary results were the rate of CSDH shrinkage and surgery avoidance. A comparison of patient characteristics between the Gorei-san (G) and non-Gorei-san (NG) groups found no significant differences in the percentage of men, average ages, past history, thickness of CSDH (15.0 ± 3.1 mm vs. 15.3 ± 2.6 mm, p = 0.801), or midline shift (2.0 ± 2.7 mm vs. 4.0 ± 5.0 mm, p = 0.230). The median surgery-free interval was significantly different between the G and NG groups [n. r. vs. 41 days (95% CI: 5-79), log-rank p = 0.047]. The CSDH avoidance rate was not significantly different between the two groups (70.0% vs. 34.4%, p = 0.071). Additionally, the CSDH shrinkage rate was significantly different between the two groups (60.0% vs. 10.3%, p = 0.004). This retrospective study demonstrated that CSDH treatment with Gorei-san reduces hematoma significantly more than treatment that does not include Gorei-san.
Keywords: Gorei-san; Kampo; chronic subdural hematoma; conservative treatment; hematoma shrinkage.