Peri-Operative Anesthesia Management of Arnold –Chiari Malformation Type 1 with Syringomyelia – A Case Report

Dr. Parmanand Mandawaria*¹, Dr. Asif Ali Khan², Ajay Babu ³ , Dr. Omar⁴

1. Specialist, Department of Anesthesia & Pain Therapy –SSMC Mayo Hospital, Abu Dhabi, UAE.

2. Specialist Surgical Intensive care Unit – SSMC Mayo Hospital Abu Dhabi, UAE.

3. Anesthesia Technologist, Department of Anesthesia & Pain Therapy –SSMC Mayo Hospital, Abu Dhabi, UAE.

4. Consultant, Department of Anesthesia & Pain Therapy – SSMC Mayo Hospital, Abu Dhabi, UAE.

*Correspondence to: Dr. Parmanand Mandawaria, Specialist, Department of Anesthesia & Pain Therapy –SSMC Mayo Hospital, Abu Dhabi, UAE.

Copyright

© 2023: Dr. Parmanand Mandawaria. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: 29 August 2023

Published: 04 September 2023

Abstract

Arnold Chiari malformation type 1 (ACM I) is anatomically defined as the displacement of the cerebellar tonsils below the level of foramen magnum. Syringomyelia is a condition in which a cavity called a syrinx develops in the spinal cord and is filled with cerebrospinal fluid. Peri operative anesthesia management needs to be careful Preoperative assessment and identifying the risk factors and challenges the appropriate planning. Here we present a case report of a 38-year-old female diagnosed as Arnold Chiari malformation type 1 with syringomyelia   she was presented to emergency department with upper limbs paresthesia and weakness, lower limbs paresthesia associated with headache, neck pain, she was urgently operated for posterior fossa decompression & C1 Laminectomy, C-MAC video Laryngoscope is used for intubation in neutral position (manual In line stabilization) to prevent neurological damage with neck movement. Patient turn in prone position, intraoperative episode of hypotension occurs manage with intravenous fluid and bolus injection of vasopressor then restore of normal blood pressure. Her postoperative period uneventful.

Keywords: Anesthesia, Arnold Chiari malformation, syringomyelia, C-MAC video laryngoscope. 

Introduction

Arnold-Chiari malformation (ACM) type I is a disorder of uncertain origin that has been traditionally defined as tonsillar herniation through the foramen magnum. The anomaly is a leading cause of syringomyelia and occurs in association with bony abnormalities at the craniovertebral junction. [1-3]. The of etiology malformation is not exactly known, but varied theories have been proposed, including molecular, hydrodynamic and mechanical mechanism. The natural history is a gradual, stepwise deterioration over many years. The ACM type I with syringomyelia may manifest with autonomic dysfunction, often asymptomatic and discovered incidentally on brain or cervical spine MRI scan. The anesthetics concern with general anesthesia are related to the risk of autonomic dysfunction, difficult airway management avoidance of sudden increase intracranial pressure damage to the spinal cord and sensitivity to neuromuscular blocking agents. we report successful management of a patient of syringomyelia with ACM who has complain of headache and neck pain & movement restricted and developed hypotension during intraoperatively period, was operated posterior fossa decompression and C1 laminectomy.

Case Report

38 years female old female weight 58 kg was admitted for urgent posterior fossa decompression and C1 laminectomy.

She was presented with c/o Neck Pain on and off since long time – worsening pain for the last 3 days radiating to left lateral neck to upper extremity, moderate nature of pain, associated with headache, no swelling no redness of neck.

Patient has No history of hypertension, no diabetes, not smoking, denies for chest pain, no shortness of breath, denies dizziness, back pain, denies nausea, vomiting.

On physical examination GCS 15/15, her pulse rate was 75/min regular, blood pressure 112/65 mmHg right arm. There was sensory hypoesthesia of upper and lower limbs, she had weakness in both upper limbs (power 3/5) and both lower limbs (power 3/5).

Routine Preoperative blood investigations were normal within normal limits. Preoperative Electrocardiogram (ECG) showed normal sinus rhythm. Chest X-ray was unremarkable.

Figure 1: MRI sagittal section showed downward herniation of the cerebellar tonsils through foramen magnum, spinal cord showing syrinx

Figure 2:  sagittal section showed posterior fossa decompression and C1 laminectomy

Her airway assessment showed a Mallampatti grade II and neck movement restricted because of pain; a difficult intubation was anticipated. MRI revealed downwards herniation of cerebellar tonsils and syrinx in spinal cord (figures 1 ). she was diagnosed as case of Arnold Chiari malformation type I (ACM) with syringomyelia. She was planned for posterior fossa decompression surgery. On arrival of the patient in Operation  Room pre holding bay after seen the base line vitals  an intravenous line was already placed ,administration of 2 mg of midazolam intravenously ,after 5 minutes patient moved in operation room, Standard monitoring continuous  ECG , heart rate(HR),non-invasive blood pressure (NIBP),oxygen saturation (Spo2 )and end -tidalCO2 (Etco2) was started before induction of anesthesia.

After adequate preoxygenation with 100 % of oxygen, anesthesia was induced with inj. fentanyl 100 mcg and inj. Propofol 120 mg. after checking the ability to achieve adequate bag and mask ventilation, inj. rocuronium 40 mg. was use for facilitate muscle relaxation. C-MAC video laryngoscope was used for intubation to prevent neurological damage associated with neck movement, a 7 mm ID reinforced endotracheal tube was used and placement confirmed by identifying bilateral breath sound plus square-wave capnograph trace. Right Internal jugular Central venous line and radial arterial cannula placed for central venous pressure, invasive blood pressure (IBP) monitoring, esophageal temperature and urine output monitoring were also started.

Patient was placed in prone position keeping the head and neck in neutral position to avoid any movement of cervical cord. And adequate padding of eyes and preventing pressure injuries of all other body parts. After prone position patient blood pressure drop down immediately bolus inj. of Phenylephrine 50 mcg given and 500 ml of intravenous crystalloid fluid rushed and restore normal blood pressure, mean arterial blood pressure (MAP) ~ 60 mmHg maintain during intraoperatively.

Anesthesia was maintained using mixture of oxygen & air (Fio2 0.5) with sevoflurane ~ 2% and intravenous Remifentanil at rate of .06 mcg / kg started continue during surgery infusion was titrated to maintain heart rate and arterial blood pressure within 20% compared with base line values. 8 mg of inj. dexamethasone and state antibiotic given before incision, surgery was last for 3 hours. Blood loss was (~50 ml) and adequate urine output replaced with crystalloid. On completion of surgery injection ondansetron 4 mg and paracetamol 1 gm IV and morphine 6 mg IV given to reduced emesis and postoperative pain respectively. At the end of surgery inj. sugammadex 200 mg IV given for reversal of neuromuscular block, patient was extubated when breathing spontaneously, eyes open, awake. Responding to verbal command, vitals were stable and shifted to SICU for observation and monitoring. Her postoperative period was uneventful, patient got relief in  headache , upper limb motor power improve , patient discharge on seventh post-operative day with advise physiotherapy and follow up in neurosurgery

Discussion

Type I ACM consist of a downward displacement of cerebellar tonsils and the medulla through the foramen magnum and spinal canal to compress the spinal cord, consequently causing blockage of the spinal canal and the stoppage of cerebrospinal flow, leading to syringomyelia (1-3). syringomyelia is a condition in which a cavity called a syrinx develops in spinal cord and filled with cerebrospinal fluid. The pathophysiology of syringomyelia consistent with the theory that a spinal subarachnoid block increases spinal subarachnoid pulse se pressure above the block, producing a pulse pressure difference across the obstructed segment of spinal subarachnoid space, which results in syringes formation and progression. (10)

Diagnosis of ACM type1 is made through a combination of patient history, neurological examination, or discovered incidentally on brain or cervical spine MRI scans. MRI is the diagnostic test of choice for ACM type I, since its easily shows the tonsillar herniation as well as syringomyelia, which occurs in 20 to 30 percent of cases. (8-9) Type I ACM patient with autonomic dysfunction can present with postural hypotension, impairment of circulatory reflexes, sinus arrhythmia, postural tachycardia. (7,11-13)

These patients if schedule for craniotomy already present with some degree of autonomic dysfunction, and significant compression of neural elements in the cranio-cervical junction. The anticipated problems to the anesthesiologists during induction, positioning for surgery, maintenance or emergence of anesthesia include autonomic dysfunction, difficulty of airway management and abnormal sensitivity to neuromuscular blocking agents. Autonomic function should be evaluated in patients with significant brainstem involvement. Subclinical autonomic dysfunction, as well recognized conditioned in ACM type I, can result in unstable hemodynamic status, lack of compensatory responses to hypotension. Invasive monitoring including: CVP for volume status, IBP for measuring continuous blood pressure should be closely monitored especially if autonomic dysfunction is suspected. Patient should be close monitored for 24 hours immediate postoperatively. (10) we use CVP monitoring to assess and management the intravascular volume in case of blood loss, IBP monitoring was started to enable close control of hemodynamic parameters and attenuate cardiovascular response to intubation, a response which could potentially stimulate progression of syrinx, and hypotension associate with postural change.

Prone position use for posterior fossa decompression. Head can be positioned in pin head holder or a horse shoe head rest, should be avoid pressure injury, pressure points well padded, anesthesiologist should have immediate attach the monitors to avoid monitoring. while we turning the in prone position avoid neck movement. intraoperatively we identified patient had episode of hypotension, patient was managed with bolus of IV fluid and phenylephrine.

In conclusion, Arnold Chiari malformation and its associated disorder may pose anesthetic risk, hence a detailed preoperative examination of autonomic dysfunction especially in cases with cervical spine syrinx should be done in order to have a better management during surgery. A safe anesthetic managements can be achieved by careful attention to the derangements that occur with the disease. Optimal patient outcome will be improved with an interdisciplinary team management including anesthesiology, neurology and neurosurgery services.

References

1.Williams B. syringomyelia. neurosurg clin N Am. 1990 Jul; 1 ((3) PubMed)

2. Milhorat TH, Bolognese PA, Nishikawa M, McDonnell NB, Syndrome of occipitoatlantoaxial hypermobility, cranial settling, and chiari malformation type I in patient with hereditary disorder of connective tissue. J Neurosurg spine .2007 Dec;7 (6):601-9. [PubMed]

3. Marin SA, Skinner CR, Da Silva VF. Posterior fossa arachnoid cyst associated with chiari I and syringomyelia. Can J Neurol Sci 2010 Mar ;37(2):273-5 [PubMed]4

4.Riveira C, Pascual J. Is chiari type I malformation a reason for chronic daily headache. Curr Pain Headache Rep 2007; 11:53-5 [PubMed]

5. Loukas M, shayota BJ, Oelhafen K,Miller JH Chen JJ, Tubbs RS, et al. Associated disorder of chiari Type I malformation :  a review . Neurosurg Focus. 2011 Sept;31(3): E3 [PubMed]