Successful Treatment with Ultrasound-Guided Aspiration of Otogenic Brain Abscess with Transmastoid Approach
Otogenic brain abscesses represent one of the most severe complications of suppurative otitis media. Despite the widespread use of antibiotics, which has significantly reduced mortality and morbidity over the years, otogenic brain abscesses still pose a substantial risk of death due to complications such as cerebral hernia or abscess rupture. In such critical cases, timely and effective drainage of the abscess is crucial for achieving favorable outcomes. This article details the successful management of a young male patient with an otogenic brain abscess and cerebral hernia using a transmastoid middle skull base craniectomy and ultrasound-guided abscess aspiration.
Case Presentation
A 22-year-old man presented to the hospital with severe headache and neck pain on the right side, accompanied by nausea. He reported a history of intermittent right ear otalgia and hearing loss over the past month. Physical examination revealed signs of acute mastoiditis and meningeal irritation. An urgent computed tomography (CT) scan showed soft-tissue density filling the middle ear cavity and mastoid, along with a bone defect in the tegmen tympani. Magnetic resonance imaging (MRI) further demonstrated inflammation in the right temporal lobe and the formation of an immature abscess.
The patient was immediately started on intravenous antibiotics (ceftriaxone and vancomycin) and mannitol, with close monitoring. However, his condition worsened the following day when he experienced a 2-minute convulsion followed by loss of consciousness. Physical examination revealed mydriasis of the right eye. A contrast-enhanced CT scan revealed an enlarged intracranial lesion in the inferior part of the temporal lobe near the skull base, measuring 3.2 cm × 2.8 cm × 3.2 cm. A small pus cavity had formed, and signs of cerebral hernia were evident.
Surgical Intervention
An urgent radical mastoidectomy of the right side was performed. During the procedure, granulation tissue was found in the mastoid, but no cholesteatoma was present. The tegmen was eroded, with an 8 mm × 5 mm bone defect, and the inflammatory dura was bulging. After removing the adherent granulation tissues, a 6 cm × 7 cm bony plate was drilled at the middle skull base through the mastoid cavity until the normal dura was exposed, effectively reducing intracranial pressure.
Given the small size of the pus cavity, ultrasound guidance was introduced to facilitate precise aspiration. The ALOKA Prosound a7 ultrasonic apparatus with a multi-frequency burr-hole transducer (UST-5268P-5) was used for brain scanning. Saline in the mastoid cavity served as the medium for gray-scale ultrasonography, which identified a 1.0 cm × 0.7 cm anechoic area with echogenic foci inside. Color Doppler mode was then used to identify the optimal puncture path, ensuring that blood vessels were not damaged.
An ultrasound-guided aspiration needle was advanced freehand through the middle cranial fossa dura into the abscess cavity. Only 1 mL of pus was aspirated, after which the brain tissue retracted, and the pulse became visible. Postoperatively, the patient regained consciousness, and his pupils returned to normal size with a normal light reflex.
Postoperative Management
Following the initial surgery, the patient underwent a 2-week course of anti-infective therapy, during which the cerebral abscess matured. A second surgery was then performed by a neurosurgeon to drain the pus, and a catheter was indwelled. After an additional 5-week course of intravenous antibiotics, all symptoms resolved, and the patient was discharged. Two months later, his muscle strength on the left side was graded as V–. No other complications were observed during the 3-year follow-up period.
Discussion
Otogenic brain abscesses remain a severe complication of otitis media, and despite the general decline in mortality rates, complications still occur. When intracranial complications become life-threatening, immediate surgical intervention is often necessary. The precise location and puncture of the abscess are critical aspects of the surgical technique.
Cerebral abscess aspiration is a rapid and safe procedure, particularly when guided by stereotactic techniques such as intraoperative ultrasound or CT scan guidance. Compared to craniotomy, imaging-guided stereotactic aspiration is considered a superior option for managing brain abscesses. CT-guided stereotaxy is the preferred method for most cerebral abscesses, except for the most superficial and large ones. However, it requires extensive preparation time and is prohibitively expensive, making it less accessible in many hospitals. Needle puncture from the transmastoid approach is often used, but it relies heavily on the surgeon’s experience to accurately locate the abscess based on preoperative CT or MRI scans.
The use of ultrasound guidance for brain abscess aspiration was first reported in 1986 by Nagle et al., who successfully aspirated a frontal brain abscess in a neonate using ultrasound guidance in the intensive care nursery. This method has since been applied in a single burr hole approach for real-time imaging of the entire procedure. However, a burr hole must first be created due to transdural attenuation.
In the present case, the patient with an otogenic brain abscess due to acute middle ear infection was treated with an immediate radical mastoidectomy when he presented with symptoms of cerebral hernia. During the mastoidectomy, a 6 cm × 7 cm bone plate of the middle cranial fossa was opened, effectively decompressing the intracranial pressure. To enhance the surgical outcome without increasing trauma or prolonging the operating time, ultrasound was introduced to guide the aspiration of the immature abscess. This approach proved successful, similar to most single-stage transmastoid drainage procedures for otogenic brain abscesses.
The abscess was primarily located within the inferior temporal lobe. Puncturing from other approaches would have resulted in a longer puncture pathway, increasing the risk of cortical damage or iatrogenic spread of infection into the ventricles. The transmastoid approach provided a short, easily monitored puncture path, significantly reducing surgical risk.
The ultrasound probe used in this case had a Z-type body, which was convenient for handheld use. With grooves on both sides, it could be easily installed into the puncture frame. Once the probe was attached to the dura, the pus cavity was clearly visualized. The volume of the pus cavity shrank immediately after aspiration. Although residual inflammation continued to grow, necessitating a second aspiration through a burr hole two weeks later, the initial single-stage mastoidectomy with ultrasound-guided aspiration via the transmastoid approach was crucial for achieving a favorable outcome.
Conclusion
The successful management of this case highlights the importance of timely surgical intervention and the use of advanced imaging techniques in the treatment of otogenic brain abscesses. The combination of radical mastoidectomy and ultrasound-guided aspiration provided an effective and minimally invasive approach to decompress intracranial pressure and drain the abscess, ultimately leading to a positive outcome for the patient.
doi.org/10.1097/CM9.0000000000000796
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