Radiographic and clinical progression from acute to chronic subdural hematoma: a systematic review

While some patients require immediate surgery for acute subdural hematoma (ASDH), others can be managed conservatively. A subset of patients, however, may experience the progression of ASDH to a relevant chronic subdural hematoma (CSDH). This systematic review aims to synthesize studies focusing on ASDH which progress to CSDH. We searched relevant databases for articles. Six issues were addressed: Which percentage of conservatively managed ASDH progressed to CSDH requiring treatment?, What were possible risk factors for this progression?, How long was the time span for chronification?, How did the clinical status change during chronification?, How did the radiographic parameters change during chronification?, How was this entity surgically treated? Fourteen studies met the inclusion criteria. The proportion of conservatively managed ASDH patients who eventually required surgery due to CSDH ranged from 6.5% to 45.3%. Several risk factors for progression were identified, with initial hematoma size and midline shift being the most significant. The majority required surgery within two to three weeks following trauma. As ASDH progressed to CSDH, a notable deterioration in clinical status occurred for many patients, including a decline in consciousness. While the hematoma density decreased, its size and midline shift increased. Most patients underwent burr hole trephination. The progression of ASDH to CSDH often led to an increase in hematoma size and midline shift, resulting in the worsening of clinical symptoms. Surgery was typically required within the second or third week after trauma for these patients.