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Table of Contents    
Year : 2021  |  Volume : 69  |  Issue : 5  |  Page : 1501-1502

Chronic Subdural Hematoma: Preventing Recurrences

Associate Professor, Department of Neurosurgery, Univ of Texas Medical Branch at Galveston, Texas, USA

Date of Submission09-Jul-2020
Date of Acceptance17-Jul-2020
Date of Web Publication30-Oct-2021

Correspondence Address:
Aaron Mohanty
301 University Boulevard, Galveston, TX 77555-0517
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.329527

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How to cite this article:
Mohanty A. Chronic Subdural Hematoma: Preventing Recurrences. Neurol India 2021;69:1501-2

How to cite this URL:
Mohanty A. Chronic Subdural Hematoma: Preventing Recurrences. Neurol India [serial online] 2021 [cited 2021 Dec 2];69:1501-2. Available from:

Chronic subdural hematomas (CSDH), a very common entity in neurosurgical practice, at times can be quite difficult to be mange. Though, several modes of management options available, currently there is no established standard of care.[1] Also, the availability of several management options for CSDH indicates that one modality of treatment is not more efficacious than the other. In CSDH the fluid collections at times can be encapsulated by membranes, that is, subdural membranes that tend to play a role in hematoma growth and recurrence. The outer parietal membrane is usually thick and vascular and exudation from the capillaries postulated to contribute to the expansion of the subdural hematoma. The inner visceral membrane is usually thin and avascular and may be adherent to the underlying arachnoid and the pia. A thick inner membrane can prevent the expansion of the brain resulting in a persistent subdural space and likelihood of recurrence of the collection in the postoperative period.

Various treatment modalities have been practiced in the management of CSDHs. Most of the CSDHs have liquefied blood which can be easily drained through a burr hole or a twist drill hole. Twist drill craniostomy with or without placement of a drain can be performed at the bedside in critically ill patients. Burr hole and evacuation of the hematoma with and without placement of drain has been perhaps the most practiced surgical option. Several studies have compared the outcome between one or two burr hole placements with two burr holes generally preferred over a single burr hole.[2] Interestingly, the preference of placing one or two burr holes has been found to be associated with geographical distribution, possibly reflecting training practices in academic neurosurgical centers.[3] A drain is conventionally placed in the subdural space though drain in the subgaleal space have also been described. When placed, a drain usually is left for 48 h in the subdural space to continuously drain the subdural space at a low resistance. Injury to the traversing veins resulting in fresh bleeding in the subdural space or parenchymal injury during placement of the drain are the most common complications associated with the placement of subdural drains.

Craniotomy and drainage of the subdural hematoma are preferred when the subdural space contains thick blood products or has an acute component (CSDH with acute bleed, often mentioned as acute on CSDH). A craniotomy also allows for breaking down multi-septate hematomas and often is combined with excision of membranes. The parietal membrane attached to the undersurface of the dura can be excised without any significant risks, while excision of the visceral membrane at times can lead to cortical venous injury resulting in thrombosis and hemorrhagic infarct. Considering this, many do not advocate excision of the visceral membrane. Craniotomy has been reported to have higher risks in the postoperative period than burr hole drainage with similar efficacy leading some to suggest that the burr hole craniostomy provided the best cure to complication ratio.[4] In another study reporting a meta-analysis of 34,829 cases, no difference in the rate of cure, recurrence, morbidity, or mortality was found between twist drill craniostomy and burr hole craniostomy. Craniotomies had a lower recurrence rate while associated with a higher rate of complications.[5] To reduce the complications of the craniotomies, mini craniotomies (40–50 mm in diameter) have been advocated by some. To confuse the issue more, recurrence was higher with mini craniotomy than with large craniotomies while mortality and complications were comparable in another study.[6] In recent years, there has been an interest in middle meningeal artery embolization either as a primary treatment or as a treatment for recurrent subdural hematomas.

One of the most perplexing postoperative complications associated with CSDH is the recurrence of the hematoma. Though rates as variable as 0–76% have been reported, the average rate falls somewhere between 10 and 20%. Several factors have been ascribed for the recurrence. A multi-separate hematoma or an organized hematoma with a thick membrane has a higher likelihood of recurrence. Similarly, non-expansion of the brain after drainage of the subdural collection with persistent subdural space can lead to the recurrence of the hematoma. An atrophic brain is seen in the old age, a thick subdural membrane preventing expansion of the brain, or insufficient drainage during the initial surgery are the common factors. The presence of a hematoma with an associated ventricular shunt which is draining fluid at low pressure will also prevent the expansion of the brain. A previous study described a persistent subdural space volume of more than 50 cm3 in the CT scan at 7 days was a significant risk factor related to the recurrence of the CSDH.[7]

In an article published in this issue, the authors report their experience with 116 patients of CSDH treated by one or two and placement of the subgaleal drain with an overall recurrence rate of 7.76%. Diffuse brain atrophy was the most contributing factor in outcome and recurrence. A lower GCS score was also associated with a poor outcome.

Considering this, the single most important factor appears to be the residual subdural space after drainage of the CSDH and an effort should be made by the surgeon to facilitate the expansion of the underlying brain. The presence of a functioning drain for 48–72 h draining the subdural fluid and promoting brain expansion will reduce the subdural space, thus reducing the recurrence of the CSDH. Some of the relevant surgical nuances include placement of at least two burr holes with the burr holes located to drain multiple cavities, copious irrigation of the subdural space, placement of the drain in the dependent burr hole site, near-total filling of the subdural space with irrigation to prevent a pneumocephalus and placing a subdural drain. Closure of the site with a large piece of Gelfoam prevents the subgaleal blood to migrate into the subdural space. Personally, I prefer placing a large-bore soft Silastic drain in the subdural space connected to a soft collection bag without any suction and placed in a dependent position for about 48–72 h. The patient is encouraged to sit up or even walk with the drain in place which permits the subdural space to drain at a very low resistance. We remove the drain when the drainage stops or the exiting subdural fluid becomes clear. We routinely perform CT scans on the first postoperative day and just before removal of the drainage which indicates the degree of brain expansion by day 3. We perform a repeat CT at around 6 weeks of time and again at around 3 months post-surgery.

  References Top

Mehta V, Harward SC, Sankey EW, Nayar G, Codd PJ. Evidence based diagnosis and management of chronic subdural hematoma: A review of the literature. J Clin Neurosci 2018;50:7-15.  Back to cited text no. 1
Kansal R, Nadkarni T, Goel A. Single versus double burr hole drainage of chronic subdural hematomas. A study of 267 cases. J Clin Neurosci 2010;17:428-9.  Back to cited text no. 2
Baschera D, Tosic L, Westermann L, Oberle J, Alfieri A. Treatment standards for chronic subdural hematoma: Results from a survey in Austrian, German, and Swiss neurosurgical units. World Neurosurg 2018;116:e983-95.  Back to cited text no. 3
Weigel R, Schmiedek P, Krauss JK. Outcome of contemporary surgery for chronic subdural hematoma: Evidence-based review. J Neurol Neurosurg Psychiatry 2003;74:937-43.  Back to cited text no. 4
Almenawer AS, Farrokhyar FA, Hong CA, Alhazzani WA, Manoranjan BA, Yarascavitch BA, et al. Chronic subdural hematoma management: A systematic review and meta-analysis of 34829 patients. Ann Surg 2014;259:449-57.  Back to cited text no. 5
Kim JH, Kang DS, Kim JH, Kong MH, Song KY. Chronic subdural hematoma treated by small or large craniotomy with membranectomy as the initial treatment. J Korean Neurosurg Soc 2011;50:103-8.  Back to cited text no. 6
Jang KM, Choi HH, Mun HY, Nam TK, Park YS, Kwon JT. Critical depressed brain volume influences the recurrence of chronic subdural hematoma after surgical evacuation. Sci Rep 2020;10:1-8.  Back to cited text no. 7


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