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Published on: August 11, 2015
The Mini-Craniotomy for cSDH Revisited: New Perspectives
Jefferson W Chen1, Jordan C Xu1, Dennis Malkasian1
1Department of Neurological Surgery, University of California, Irvine, Orange, CA, United States.
Insights
Mini-craniotomy effectively treats chronic subdural hematomas (cSDH) by releasing the inner membrane, preventing recurrence. This neurosurgical approach shows promising results in improving patient outcomes.
Area of Science:
- Neurosurgery
- Radiology
- Neurology
Background:
- Chronic subdural hematomas (cSDH) are increasingly common, particularly in aging populations and those using anticoagulants.
- Current treatments for cSDH, including surgical and medical options, have variable success rates.
- Recurrence rates for cSDH historically range from 5% to 30%.
Purpose of the Study:
- To evaluate the efficacy of mini-craniotomy with inner membrane fenestration for cSDH treatment.
- To assess the impact of pre-operative CT findings on surgical decision-making and outcomes.
- To investigate the role of brain re-expansion and glymphatic flow in cSDH management.
Main Methods:
- Retrospective review of 34 consecutive mini-craniotomies for cSDH performed by a single surgeon.
- Analysis of patient demographics, pre-operative CT findings (including inner membrane signs, midline shift), and surgical details.
- Extraction of post-operative outcomes such as recurrence, seizures, infections, and length of stay from electronic medical records.
Main Results:
- Mini-craniotomy was the primary treatment for 29 patients, with a mean age of 68.9 years.
- Pre-operative CT scans indicated inner subdural membranes in 33 patients, and fenestration was performed in all but one case.
- No symptomatic recurrences, re-operations, or surgical site infections were observed within 6 months of follow-up.
Conclusions:
- Pre-operative CT identification of inner subdural membranes can guide targeted mini-craniotomy.
- Mini-craniotomy with inner membrane fenestration is a highly effective treatment for cSDH, achieving zero recurrence in this series.
- Brain re-expansion and restored interstitial flow, potentially linked to glymphatic pathways, may be crucial for favorable long-term cSDH outcomes.
Abstract:
Background: Chronic subdural hematomas (cSDH) are increasingly prevalent worldwide with the increased aging population and anticoagulant use. Different surgical, medical, and endovascular treatments have had varying success rates. Primary neurosurgical interventions include burr hole drainage of the cSDH and mini-craniotomies/craniotomies with or without fenestration of the inner membrane. A key assessment of the success or failure of cSDH treatments has been symptomatic recurrence rates which have historically ranged from 5 to 30%. Pre-operative prediction of the inner subdural membrane by CT scan was used to guide our decision to perform mini-craniotomies. Release of the inner membrane facilitates the expansion of the brain and likely improves glymphatic flow. Methods: Consecutive mini-craniotomies (N = 34) for cSDH evacuation performed by a single neurosurgeon at a quaternary academic medical center/Level I trauma center from July 2018-September 2020 were retrospectively reviewed. Patient characteristics [age, gender, presenting GCS, GOS, initial CTs noting the inner subdural membrane, midline shift (MLS), cSDH width, inner membrane fenestration, cSDH recurrence, post-operative seizures, infections, length of stay] were extracted from the EMR. Results: Twenty nine patients had mini-craniotomies as primary treatment of the cSDH. Mean age = 68.9 ± 19.7 years (range 22-102), mean pre-operative GCS = 14.5 ± 1.1, mean MLS = 6.75 ± 4.2 mm, and mean maximum thickness of cSDH = 17.7 ± 6.0 mm. Twenty four were unilateral, five bilateral, 34 total craniotomies were performed. Thirty three had inner membrane signs on pre-operative head CTs and an inner subdural membrane was fenestrated in all cases except for the one craniotomy that didn't show these characteristic CT findings. Mean operating time = 79.5 ± 26.0 min. Radiographic and clinical improvement occurred in all patients. Mean improvement in MLS = 3.85 ± 2.69. There were no symptomatic recurrences, re-operations, surgical site infections, or deaths during the 6 months of follow-up. One patient was treated for post-operative seizures with AEDs for 6 months. Conclusion: Pre-operative CT scans demonstrating inner subdural membranes may guide one to target the treatment to allow release of this tension band. Mini-craniotomy with careful fenestration of the inner membrane is very effective for this. Brain re-expansion and re-establishment of normal brain interstitial flow may be important in long term outcomes with cSDH and may be related to the recent interests in brain glymphatics and dural lymphatics.
