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Subdural hematoma (SDH) rarely presents as an encapsulated lesion with acute neurological deterioration.[1] Rapid neurological recovery following surgical intervention in such cases is even less frequently reported. The present case adheres to the CARE (CAse REport) guidelines and provides valuable insights into the diagnosis, surgical decision-making, and perioperative management of encysted SDH.

A 72-year-old female with a 1-month history of trivial fall presented with progressive drowsiness and right upper limb weakness for 3 days. Neurological examination revealed a Glasgow Coma Scale score of E4V4M6, right upper limb motor power of 0/5, and left-sided lower motor neuron facial palsy (House–Brackmann grade IV). Preoperative neuroimaging revealed a left frontoparietal, well-defined, encapsulated subdural collection with internal septations and mass effect, consistent with an encysted chronic SDH.

Standardized anesthetic induction was performed to maintain adequate cerebral oxygenation. Nitrous oxide was avoided during the anesthetic maintenance. Scalp block was given bilaterally under ultrasound guidance. Given the acute neurological deterioration and presence of dense focal deficits, the surgeon initially made a burr hole. However, on incising the membrane, there appeared to be clotted blood. Therefore, the surgical plan was appropriately revised to a left fronto-temporo-parietal craniotomy, which allowed direct visualization and excision of the thick outer membrane and adhesions ([Figs. 1] and [2]). Sharp dissection and removal of the membrane were performed, followed by evacuation of altered clots. This resulted in a lax and pulsatile brain. Once hemostasis was attained, standard dural and bone flap closure were performed. Postoperatively, the facial palsy resolved within 24 hours after surgery (House-Brackmann grade 1), and the motor power also improved to ⅘.

Fig. 1 This intraoperative photograph demonstrates an encysted subdural hematoma, appearing as an encapsulated chronic collection with a well-defined membrane (central grayish area). It is surrounded by inflamed and hypervascularized dura mater and arachnoid tissues, indicative of chronic inflammation and an attempted healing response. This figure highlights the typical appearance and anatomy encountered during the evacuation of a chronic, encysted subdural hematoma in the brain.Fig. 2 These axial slices of a computed tomography scan reveal the encysted subdural hematoma.

Encysted SDH is an uncommon variant of chronic SDH and is believed to result from repeated microbleeds, organization of hematoma contents, and progressive neomembrane formation. Such cases may present acutely with severe focal neurological deficits, mimicking other intracranial pathologies. The presence of a thick capsule and multiloculated hematoma underscores the limitations of burr-hole evacuation in these scenarios. Several reports have emphasized that craniotomy with membrane excision offers superior neurological outcomes in selected patients with encapsulated SDH, particularly when rapid deterioration or focal deficits are present.

Anesthetic induction in neurotrauma patients requires preservation of cerebral oxygenation for good postoperative outcomes.[2] Cerebral oximetry has been used even to detect intracerebral hematoma prior to neuroimaging.[3] Ultrasound-guided scalp blocks have emerged as promising adjuncts in anesthesia management in recent literature. They boost faster emergence and recovery from anesthesia.[4] Avoidance of nitrous oxide is pivotal to ensure intraoperative visualization of parenchymal structures and avoidance of brain bulge, as nitrous oxide shall increase the intracranial pressure.[5]

Encapsulation may arise from repeated microbleeds or organized chronic SDH, resulting in acute presentations. [Table 1] summarizes previously reported cases of SDH associated with facial nerve palsy. Consistent with prior literature, our patient showed rapid and near-complete neurological recovery following membrane excision and clot evacuation, reinforcing the role of aggressive surgical management in carefully selected cases. Encysted SDH, though rare, is a surgically reversible entity when managed aggressively and appropriately. Future directions include creation of exploratory models for the prediction of successful neurological recovery after surgery, as seen in the recent trend.[6]

Table 1 A review of cases with facial nerve paralysis after SDH

Author (Year)

Age and gender

Clinical presentation

Outcome

Ferber et al (2023)[7]

81-y female

Bilateral SDH - underwent bilateral MMA embolization - developed Grade V (House-Brackmann) left facial nerve palsy, which partially improved to Grade III but was persistent at outpatient follow-up (approximately 83 d post-embolization)

Paralysis partially improved to Grade III but was persistent at outpatient follow-up done until 83 d post-embolization

Cristaldi et al (2024)[8]

61-y female

Left chronic SDH - patient developed left facial palsy after MMA embolization

Facial nerve palsy partially resolved

Pilawska et al (2025)[9]

82-y male;

36-y male;

87-y male

Chronic SDH - developed facial palsy after embolization using Onyx

First case - loss to follow-up;

Second case - facial nerve palsy partially resolved;

Third case - permanent facial nerve palsy

Abbreviations: MMA, middle meningeal artery; SDH, subdural hematoma.

This case highlights the importance of early recognition and appropriate surgical strategy in patients with encapsulated SDH presenting with acute neurological deficits. Although burr-hole evacuation remains the standard treatment for uncomplicated chronic SDH, craniotomy with membrane excision is justified in cases with thick encapsulation, multiloculation, and rapid neurological deterioration. Prompt surgical intervention can lead to dramatic neurological recovery, even in elderly patients. Encysted SDH, though rare, is a surgically reversible entity when managed aggressively and appropriately.

Publication History

Article published online:
29 April 2026

© 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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