|
|||||||||||||||||||||
|
Management of Left Cerebello-Pontine Angle Tumour using Intraoperative Neurophysiological Monitoring and Cavitron Ultrasonic Surgical Aspirator in a Pregnant Patient: A Case Report |
|||||||||||||||||||||
|
Swapnilkumar Nakhale, TP Jeyaselva Senthilkumar, Bhaurao D Nakhale 1. Senior Resident, Department of Neurosurgery, SRM Medical College, Chennai, Tamil Nadu, India. 2. Professor and Head, Department of Neurosurgery, SRM Medical College, Chennai, Tamil Nadu, India. 3. Professor, Department of General Medicine, Datta Meghe Medical College, Wardha, Maharashtra, India. |
|||||||||||||||||||||
|
Correspondence Address : Dr. Swapnil Kumar Nakhale, Senior Resident, Department of Neurosurgery, SRM Medical College, Chennai-603203, Tamil Nadu, India. E-mail: swapnilnakhale20@gmail.com |
|||||||||||||||||||||
|
|||||||||||||||||||||
| ABSTRACT |  | ||||||||||||||||||||
: Vestibular Schwannoma (VS) is a benign tumour of the vestibulocochlear nerve and accounts for nearly 85% of Cerebello-Pontine (CP) angle tumours. Its occurrence during pregnancy is infrequent, with only a few cases reported worldwide. Managing VS in pregnant patients presents unique challenges, as both maternal neurological status and foetal safety must be considered when deciding the timing and approach to surgery. We report the case of a 23-year-old primigravida at 12 weeks of gestation who presented with progressive headache, blurred vision, imbalance, and left-sided hearing loss. Neurological examination revealed bilateral papilloedema, left facial nerve involvement, sensorineural hearing loss, with Magnetic Resonance Imaging (MRI) brain showing a left CP angle tumour with hydrocephalus. The patient initially underwent an emergency right ventriculoperitoneal shunt for symptomatic relief, followed by a retromastoid suboccipital craniotomy for tumour excision under Intraoperative Neurophysiological Monitoring (IONM). The tumour was safely debulked using a Cavitron Ultrasonic Surgical Aspirator (CUSA), which allowed selective tumour removal with the preservation of critical neurovascular structures. The patient recovered without new neurological deficits, continued her pregnancy to term, and delivered a healthy baby via caesarean section. Histopathological examination confirmed VS, and postoperative MRI at six months showed gross total resection with no recurrence. | |||||||||||||||||||||
|
|
|||||||||||||||||||||
| Keywords : Cerebellopontine angle tumour, Foetal safety, Pregnancy, Ventriculoperitoneal shunt, Vestibular schwannoma | |||||||||||||||||||||
|
|
|||||||||||||||||||||
|
DOI and Others :
DOI: 10.7860/IJARS/2026/80555.3075
Date of Submission: May 13, 2025 Date of Peer Review: Aug 21, 2025 Date of Acceptance: Oct 29, 2025 Date of Publishing: Jan 01, 2026 AUTHOR DECLARATION: • Financial or Other Competing Interests: None • Was informed consent obtained from the subjects involved in the study? Yes • For any images presented appropriate consent has been obtained from the subjects. Yes PLAGIARISM CHECKING METHODS: • Plagiarism X-checker: May 13, 2025 • Manual Googling: Oct 20, 2025 • iThenticate Software: Oct 28, 2025 (10%) ETYMOLOGY: Author Origin EMENDATIONS: 6 |
|||||||||||||||||||||
|
|
|||||||||||||||||||||
| Case Report |
| ||||||||||||||||||||
A 23-year-old primigravida with 12 weeks of gestational age with no known co-morbidities, was admitted to the obstetrics department with chief complaints of blurred vision for the past 15 days, increased watering in the left eye for the same duration, difficulty in balancing while walking for the past six months, a year-long history of headache, unilateral left-sided hearing loss for the past year, which has progressively worsened. While she can hear sounds, she has difficulty understanding words. There is no history of ear discharge or earache. The patient was reportedly well one year ago when she began experiencing an insidious, progressive early morning headache, initially localised to the occipital region but later becoming holocranial. There is no history of projectile vomiting, convulsions, or loss of consciousness. There has been no significant worsening of symptoms in the dark. On examination, the patient was conscious and oriented. Evaluation of the cranial nerves revealed established papilloedema in both eyes, indicating involvement of the optic nerves {second Cranial Nerve (CN)}. Examination of the facial nerve (seventh CN) showed subtle lagophthalmos of the left eye with associated epiphora, and the corneal reflex was absent on the same side. Assessment of the vestibulocochlear nerve (eighth CN) demonstrated sensorineural hearing loss in the left ear. The Weber test lateralised to the right ear, and the Rinne test showed air conduction greater than bone conduction bilaterally. The patient also exhibited bilateral Brunsting nystagmus and gait ataxia, with leftward swaying. MRI brain was done, suggestive of an extra-axial lesion measuring ~4.9×4.8×4.9 cm (TR×CC×AP), seen in the left cerebello-pontine angle cistern (Table/Fig 1), (Table/Fig 2). Mass effect noted over the left cerebellar hemisphere, vermis, pons, midbrain, with displacement towards the right and compression of the 4th ventricle, causing obstructive hydrocephalus and subtle periventricular ooze (Table/Fig 3). Based on the clinical presentation and radiological findings, the patient was diagnosed with a left CP angle tumour, associated with hydrocephalus and features of raised Intracranial Pressure (ICP). The options for management included: i. Ventriculoperitoneal (VP) shunt placement to relieve hydrocephalus, followed by definitive tumour surgery, with a noted risk of miscarriage during the course of treatment. ii. Medical Termination of Pregnancy (MTP) followed by VP shunting and definitive surgery, though this was not emphasised due to the benign nature of the tumour. Emergency right VP shunting was done as it was hydrocephalus with symptoms of raised intracranial tension, like blurring of vision, headache, and to provide temporary relief from her symptoms and give time for relatives to decide on a major definitive procedure, along with termination or continuation of pregnancy. VP shunting was done under observation of the Gynaecology team with continuous monitoring of fetal heart sound. The patient was extubated on the operating table to reduce exposure to anaesthetic medications, which can be harmful to the foetus. The patient was managed in the neurosurgery Intensive Care Unit (ICU) for one day. The patient became symptomatically better and there was resolution in headache and blurring of vision (Table/Fig 4). Relatives were counselled for definitive surgery, risk of foetal demise and the patient was posted for retromastoid suboccipital craniotomy with tumour excision under intraoperative neuro monitoring under general anaesthesia. We positioned the patient under the park bench position with general anaesthesia without muscle relaxation. We routinely use intraoperative neurophysiological monitoring for these kinds of patients, but using high current Motor Evoked Potential (MEP) stimulations may promote uterine contractions and miscarriage. So, we used minimal current for IONM and also reduced the number of MEP recordings. The image depicts transcranial MEP (TcMEPs). The recorded traces are labelled APB-APB, representing the abductor pollicis brevis (a hand muscle), and AH-AH, representing the abductor hallucis (a foot muscle). These distal muscles are commonly monitored to assess the integrity of the corticospinal tract. The vertical scale is set at 100 μV per division, and the horizontal scale at 10 ms per division. The bursts of activity in the traces correspond to motor responses generated by cortical stimulation and recorded peripherally. On the right side of the image, a timeline lists intraoperative events such as CUSA, TUM (tongue muscles), FACI (facial muscles), and ORIS (orbicularis oris), which help to correlate neurophysiological changes with specific surgical manoeuvers (Table/Fig 5). The main purpose of this monitoring is to detect any potential injury to the descending motor pathways during tumour resection or other brain and spinal surgeries. This screen displays free-running Electromyography (EMG) activity from muscles innervated by various cranial nerves. The monitored channels include FR (frontalis) representing the facial nerve (CN VII), OR (orbicularis oculi/oris) also innervated by CN VII, MT (mentalis) corresponding to CN VII, MAS (masseter) linked to the trigeminal nerve (CN V), TRAP (trapezius) representing the spinal accessory nerve (CN XI), and HYPO (hypoglossus) corresponding to the hypoglossal nerve (CN XII). The vertical scale is set at 200 μV per division, and the horizontal scale at 5 ms per division. Bursts of neurotonic discharges visible in some channels typically suggest mechanical irritation or manipulation of the associated cranial nerve during surgery. The purpose of this monitoring is to provide real-time feedback to the surgeon, allowing immediate recognition of nerve irritation and helping to prevent permanent cranial nerve injury (Table/Fig 6). Retromastoid suboccipital craniotomy was done under microscope and IONM guidance (Table/Fig 7), (Table/Fig 8), (Table/Fig 9). Being in a hyperdynamic state in pregnancy, maternal haemodynamics were continuously monitored intraoperatively and Post (POV) operatively, baseline Heart Rate (HR) 84-98/min with Blood Pressure (BP) 130/80 mmHg, HR maintained 80-90/min, Mean Arterial Pressure (MAP) 7.-85 mmHg, expected blood loss was around 500 mL, crystalloids 2 L and one unit packed red blood cells transfused, as tumour was vascular, and we encountered incessant bleeding during surgery, which was managed by slow meticulous dissection, packing with Surgicel and using bipolar cautery along with blood transfusion. Tumour debulking was performed with the assistance of CUSA, which allowed piecemeal ultrasonic fragmentation with preservation of surrounding neurovascular structures. Continuous foetal HR monitoring was maintained by the obstetric team throughout the surgery. Postoperatively, the patient was extubated on the table and was kept under observation in the Neurosurgery ICU for one day. Postoperatively, the patient had preserved facial nerve function and no further neurological deficits. Patient continued the pregnancy until 37 weeks when a healthy infant was delivered via caesarean section. Follow-up MRI showed gross total resection with no evidence of recurrence at six months (Table/Fig 10). Histopathological Examination (HPE) report of a tumour suggestive of a (Table/Fig 1). | |||||||||||||||||||||
| Discussion |
| ||||||||||||||||||||
The VS make up around 85% of all CP angle tumours with an estimated lifetime occurrence of about 1 in 1000 individuals. Most cases arise sporadically, though roughly 5% are associated with Neurofibromatosis Type 2 (NF2), a genetic tumour predisposition syndrome (1). It poses a unique set of challenges when encountered during pregnancy (2). Comprehensive studies on schwannoma in pregnancy are limited due to its low incidence (3). VS typically present with hearing loss and dizziness, and may also cause headache or tinnitus. Diagnosing these symptoms during pregnancy can be difficult, and the condition often goes unnoticed until marked neurological deficits develop (4). Although these tumours usually grow slowly, the elevated oestrogen levels and increased blood flow seen in pregnancy are believed to accelerate their growth. This can lead to rapidly worsening symptoms and, in some cases, acute obstructive hydrocephalus. The so-called “oestrogen irrigation effect” is thought to promote tumour enlargement, so diagnosis often occurs when the tumour has reached a considerable size. Additionally, the physiological changes of pregnancy- such as increased blood volume, higher jugular venous pressure, and hormonal influences- can worsen tumour swelling, cause peritumoural effusion, and increase the risk of intratumoural haemorrhage (5). Selecting the appropriate brain imaging technique during pregnancy requires weighing the chances of a serious neurological condition against the diagnostic value and potential risks of MRI or Computed Tomography (CT). Radiation exposure from a head CT is minimal and carries almost no risk to the foetus, so it should not be postponed in urgent situations. MRI without contrast is also considered safe, as no adverse foetal effects have been reported. When contrast is needed, iodinated agents used in CT are generally safer than gadolinium used in MRI, since gadolinium can accumulate in foetal tissues. In most cases, the danger of missing or delaying diagnosis outweighs the small potential risks of imaging (6). VS occurring during pregnancy is rare and poses complex management challenges because both maternal and foetal safety must be considered when deciding the timing of surgery. Surgery during the first trimester (1-12 weeks) is generally avoided, as anaesthesia and surgical stress can harm the foetus, so conservative management is preferred unless there is hydrocephalus or severe neurological decline. The second trimester (13-24 weeks) is considered the safest window for tumour removal, as the risk of miscarriage or foetal malformation is lower, and maternal physiology is more stable. Surgery at this stage is reserved for patients with large tumours (over 3 cm), brain compression, or worsening neurological symptoms. By the third trimester (25-36 weeks), surgery becomes risky due to altered maternal haemodynamics and increased bleeding potential. Most patients diagnosed late in pregnancy are managed conservatively. Once delivery is completed safely, surgical resection of the tumour can be performed under more controlled conditions (5). IONM is widely used in neurosurgery, and our case shows that it can be safely and effectively applied during pregnancy. With proper supervision, MEP-based monitoring does not pose any risk to either the mother or the foetus. Good outcomes depend on customised stimulation protocols, continuous real-time foetal monitoring, and close coordination within a multidisciplinary team (7). The CUSA allows surgeons to precisely remove tumour tissue while preserving delicate structures such as blood vessels, pia mater, and cranial nerves. This approach enables internal tumour debulking with minimal retraction, improved visualisation, and reduced blood loss-thereby lowering the risk of mechanical and ischemic injury to the surrounding brain. The CUSA tip uses ultrasonic vibrations to create cavitation and mechanical impact that selectively emulsifies soft tumour tissue, while more elastic structures resist fragmentation. This selective action helps protect normal brain tissue. By debulking the tumour from the inside out, surgeons can reduce the need for brain retraction, minimising trauma and improving postoperative outcomes (8). Clinical series and device reports show CUSA helps preserve arteries and cranial nerves during brain tumour and skull-base resections because those structures are less easily emulsified than tumour (9). Surgery was indicated in our case during pregnancy because the tumour was large in size and the patient was having features of raised ICP. The tumour is most likely to expand in size in subsequent months, causing brainstem compression, and we may lose the patient. | |||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|
|||||||||||||||||||||
Case report
|
Full Version