Anesth Pain Med 2012; 7: 166～169 ￭Case Report￭

Anesthetic management of a patient with Arnold- type I with associated -A case report-

Department of Anesthesiology and Pain Medicine, Wonkwang University Hospital, Iksan, Korea

Tai-Yo Kim, Cheol Lee, and Ji-Na Kim

Arnold-Chiari malformation type I (ACM I) is anatomically defined for suboccipital craniectomy, cervical laminectomies and dura- as the displacement of the cerebellar tonsils below the level of the plasty. He had been diagnosed with Arnold-Chiari malforma- . Syringomyelia is a condition in which a cavity tion type I and its syringomyelia 10 years previously. Neurolo- called a syrinx develops in the and is filled with . Here we report the anesthetic management of gical symptoms including occipital headache, slurred speech, a case of ACM I with associated syringomyelia scheduled for swallowing difficulty, weakness with atrophy in upper limbs, suboccipital craniectomy, cervical laminectomy and duraplasty. of face, chest, and upper limbs, and loss of (Anesth Pain Med 2012; 7: 166∼169) temperature and pain sensation had gradually progressed. Key Words: Anesthetic management, Arnold-Chiari malformation Especially, occipital headache was aggravated by coughing, type I, Syringomyelia. sneezing, or laughing. But balance and motor function were not affected. His cervical spine X-ray and computerized tomography (CT) (Fig. 1 and 2) showed bony fusion and def- Arnold-Chiari malformation type I (ACM I) is a disorder of ormity at the upper cervical spine and base. Magnetic uncertain origin that has been traditionally defined as tonsilar resonance imaging (MRI) revealed downward herniation of the herniations of 3 to 5 mm or greater through the foramen cerebellar tonsils below the foramen magnum, syringomyelia, magnum. The anomaly is a leading cause of syringomyelia and fusion state of upper cervical spine and occurs in association with bony abnormalities at the cranio-ver- tebral junction [1-3]. Generally, ACM I and its associated disorders pose anesthetic risk; difficulty of airway management, autonomic dysfunction, avoidance of sudden increased intracra- nial pressure, and abnormal sensitivity to neuromuscular block- ing agents. We present the anesthetic management of a case of ACM I and its associated syringomyelia scheduled for subocci- pital craniectomy, cervical laminectomies and duraplasty.

CASE REPORT

A 34-year-old man patient weighing 68 kg was scheduled

Received: March 5, 2012. Revised: March 16, 2012. Accepted: March 18, 2012. Corresponding author: Cheol Lee, M.D., Department of Anesthesiology and Pain Medicine, Wonkwang University Hospital, 344-2, Sinyong-dong, Iksan 570-711, Korea. Tel: 82-63-859-1560, Fax: 82-63-857-5472, E-mail: Fig. 1. Lateral cervial X-ray showed bony fusion and deformity at the [email protected] upper cervical and skull base.

166 Tai-Yo Kim, et al：Anesthesia of Arnold-Chiari malformation 167 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

Fig. 2. Cervial sagittal (A) and coronal (L) CT with bone window settings show- ed severe deformity with basilar invagi- nation and atlanto-axial assimilation.

and severe limitation of cervical spine mobilization. Preopera- tive electrocardiography (ECG) showed sinus arrhythmia and chest X-ray was unremarkable. In the operation room, the patient was monitored with pulse oximetry, invasive radial arterial and non-invasive automated blood pressure, capnography, bispectral index (BIS) and eso- phageal temperature probe. Muscle relaxation was monitored with peripheral nerve stimulator. There were anticipated diffi- culties with airway management in airway examinations. We therefore decided to perform nasal intubation under fiberoptic bronchoscopic control prior to ; this would be done with the patient awake. After intravenous midazolam 3 mg and a slow (60 seconds) bolus dose of remifentanil 0.5 μg/kg and followed by remifentanil infusion 0.15 μg/kg/min, the instru- ment was passed and lidocaine 10% sprayed under direct Fig. 3. Sagittal T1-weighted MRI showed downward herniation of the vision, via a small nylon catheter, onto and through the vocal cerebellar tonsils through the formamen magnum suggesting ACM I and cords. A well-greased and warmed 7.00 mm cuffed tracheal syrinx within the cervial cord along the C2 and C3. tube was then threaded over fiberoptic bronchoscopy which was introduced into the right nasal passage and both tube and (Fig. 3). Anesthesiologists and neurosurgeons discussed the scope were advanced to negotiate the corner into the pharynx. possibility to increase with anesthetic and The scope was then maneuvered so that its tip passed through surgical procedures. We decided not to perform intracranial the vocal cords and the tube was passed into the trachea using pressure monitoring in this patient because corrective surgery the scope as a guide. The position of the tube was checked for this patient was supposed to decompress increased intracra- visually by reference to the carina, and by auscultation and nial pressure accompanied by ACM. confirmed by capnography. Routine preoperative investigations were within normal Following tracheal intubation, anesthesia was induced with limits. Airway examinations displayed an interincisor distance propofol 2 mg/kg and maintained with a mixture of oxygen/air of 3 cm, Mallampati class III, thyromental distance of 6 cm, (FiO2 0.5) and intravenous infusion of propofol and remifen- 168 Anesth Pain Med Vol. 7, No. 2, 2012 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏 tanil. Propofol infusion was titrated to maintain a BIS index of well as syringomyelia, which occurs in 20 to 30 percent of 40−60, a remifentanil infusion was titrated to maintain heart cases [6]. rate and arterial blood pressure within 20% compared with The patients with ACM I and syringomyelia scheduled for baseline values. Rocuronium 40 mg was given for proper craniectomy already present with some degree of neurologic muscle relaxation. Normocapnia was maintained throughout the involvement, which indicates significant compression of the procedure with a peak airway pressure 25 mmHg. The patient neural elements in the craniocervical junction. In patients with was covered by warming blanket to maintain normal body ACM I and syringomyelia, there is no evidence that any temperature during surgery. There were no significant changes particular anesthetic agents are contraindicated and the proper in the hemodynamic status and body temperature of the patient anesthetic management has not yet been established. However, until the end of surgery. Neuromuscular blockade was reversed anesthetic management should begin with careful investigation with pyridostigmine 0.2 mg/kg, glycopyrrolate 0.008 mg/kg of the medical history and a complete physical examination of when the TOF ratio had returned to 25% at the end of the patient’s airway, respiratory, cardiovascular, and neurologic surgery. When BIS values reached 80 and spontaneous breath- systems to exclude possible associated comorbidity. Patients ing was achieved, extubation was performed. The patient was with these conditions can pose challenges to the anesthesio- administered by patient-controlled analgesia pump logists during induction, maintenance or emergence of anesthe- containing morphine (60 mg), ketorolac (180 mg), and ramose- sia and positioning; 1) difficulty of airway management, 2) tron (0.6 mg) in normal saline in a total volume of 100 ml. autonomic dysfunction, 3) avoidance of sudden increased intra- The patient was transferred to the neurosurgical intensive cranial pressure, and 4) abnormal sensitivity to neuromuscular care unit where he was under close observation for a day after blocking agents. surgery. He was transferred to the general ward after stabili- First, ACM I is associated with bony abnormalities including zation. The patient’s postoperative recovery was uneventful and cervical spine fusion at the cranio-vertebral junction, which discharged home 14 days after surgery. lead to limited range of motion. Flexion-extension of the should be limited to prevent further compression of the neural TM DISCUSSION structure. Airtraq laryngoscope or fiberoptic bronchoscopic intubation instead of standard laryngoscope is recommended in The prevalence of ACM I defined as tonsilar herniations of patients with skeletal cervical spine abnormalities and unstable 3 to 5 mm or greater is estimated to be in the range of one cervical spine [2,7]. Careful planning for extubation, and per 1,000 to one per 5,000 individuals [1]. The incidence of possibly postoperative respiratory support with slow weaning, is symptomatic ACM I is less but unknown. Other conditions indicated in patients with pronounced compression sometimes associated with ACM I include , and cranial nerve involvement, owing to increased risk of syringomyelia, abnormal spinal curvature, tethered spinal cord postoperative ventilator failure [8] or compromised upper air- syndrome, and connective tissue disorders such as Ehlers- way reflexes [9]. Our patient had severe limitation of cervical Danlos syndrome and [3]. The ACM I is spine mobilization due to deformity and cervical spine fusion associated with the various skeletal and CNS abnormalities at the cranio-vertebral junction and therefore was intubated via including basilar impression, atlanto-occipital fusion, atlanto- flexible fiberoptic bronchoscopy from the start. After surgery, axial assimilation, , or syringomyelia. The signs and the patient was transferred to the neurosurgical intensive care symptoms of ACM I can be divided into those caused by the unit where he was under close observation for a day. compression of dural or neural structure by the displaced Second, autonomic function should be evaluated in patients cerebellar tonsils and those related to the progressive develop- with significant brainstem involvement. Subclinical autonomic ment of syringomyelia. The patients with ACM I usually dysfunction, a well recognized condition in ACM I, can result become symptomatic in the late teens. However, some may in unstable hemodynamics, lack of compensatory response to first display symptoms at a more advanced age, even in the hypothermia, hypotension, hypoxia, and hypocarbia intraopera- presence of the syringomyelia [4,5]. Diagnosis of ACM I is tively. Invasive arterial blood pressure is monitored for mea- made through a combination of patient history, neurological suring continuous blood pressure and blood gases analysis and examination, and MRI. MRI is the diagnostic test of choice body temperature should be closely monitored especially if for ACM I, since it easily shows the tonsilar herniation as autonomic dysfunction is suspected. The patient should be Tai-Yo Kim, et al：Anesthesia of Arnold-Chiari malformation 169 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏 closely monitored in the immediate 24 hours following surgery the derangements that occur with the disease. Optimal patient because of the risk of sudden , cardiac arrest in outcome will be improved with an interdisciplinary team syringomyelia associated with autonomic dysfunction [10]. Our management including anesthesiology, neurology and neurosur- patient was covered with warming blanket and monitored core gery services. temperature via esophageal temperature probe to maintain body temperature. A remifentanil infusion, and invasive radial arterial ACKNOWLEDGEMENTS blood pressure monitoring enable close control of hemodynamic parameters and effectively attenuated cardiovascular response to This article was supported by Wonkwang University 2011. intubation, a response which could potentially stimulate progre- ssion of a syrinx. REFERENCES Third, sudden increase of intracranial pressure caused by induction, intubation, positioning, or extubation lead to spinal 1. Milhorat TH, Bolognese PA, Nishikawa M, McDonnell NB, cord damage. The chosen anesthetic technique must firstly aim Francomano CA. Syndrome of occipitoatlantoaxial , to avoid elevating intracranial pressure or changing cranio-spi- cranial settling, and chiari malformation type I in patients with nal pressure gradients [11]. Normocapnia should be maintained hereditary disorders of connective tissue. J Neurosurg Spine 2007; and high airway pressures avoided to prevent any rise in 7: 601-9. 2. Mustapha B, Chkoura K, Elhassani M, Ahtil R, Azendour H, intracranial pressure. Intravenous anesthetics except ketamine Kamili ND. Difficult intubation in a parturient with syringomyelia are more advantageous compared with volatile anesthetics for and Arnold-Chiari malformation: Use of Airtraq laryngoscope. decreasing intracranial pressure. We used propofol as an Saudi J Anaesth 2011; 5: 419-22. anesthetics of induction and maintenance in our patient. 3. Loukas M, Shayota BJ, Oelhafen K, Miller JH, Chern JJ, Tubbs Normocapnia via capnography and analysis of arterial blood RS, et al. Associated disorders of Chiari Type I malformations: a review. Neurosurg Focus 2011; 31: E3. gas was maintained throughout the procedure with a peak 4. Kojima A, Mayanagi K, Okui S. Progression of pre-existing Chiari airway pressure 25 mmHg. type I malformation secondary to cerebellar hemorrhage: case Fourth, patients with syringomyelia have an increased sensiti- report. Neurol Med Chir (Tokyo) 2009; 49: 90-2. vity to neuromuscular blocking agents [2,9]. The presence of 5. Riveira C, Pascual J. Is Chiari type I malformation a reason for syringomyelia is determined even in patients without a clinical chronic daily headache. Curr Pain Headache Rep 2007; 11: 53-5. picture of . Succinylcholine should not be used to 6. Strahle J, Muraszko KM, Kapurch J, Bapuraj JR, Garton HJ, Maher CO. Chiari malformation Type I and syrinx in children facilitate rapid intubation of the trachea. It is associated with undergoing magnetic resonance imaging. J Neurosurg Pediatr hyperkalemia when given to patients with denervated muscle. 2011; 8: 205-13. The presence and location of motor deficit is noted to avoid 7. Daum RE, Jones DJ. Fibreoptic intubation in Klippel-Feil overdosing non-depolarizing muscle relaxants by monitoring syndrome. Anaesthesia 1988; 43: 18-21. blockade on denervated muscles. It is therefore important to 8.Williams DL, Umedaly H, Martin IL, Boulton A. Chiari type I monitor the neuromuscular junction throughout the surgery. In malformation and postoperative respiratory failure. Can J Anaesth 2000; 47: 1220-3. our patient with weakness and atrophy of upper limb, rocuro- 9. Agusti M, Adalia R, Fernandez C, Gomar C. Anaesthesia for nium was used with for proper muscle relaxation accompanied caesarean section in a patient with syringomyelia and by monitoring of neuromuscular function. He had normal Arnold-Chiari type I malformation. Int J Obstet Anesth 2004; 13: return to full muscle function following a standard induction 114-6. dose of rocuronium. 10. Gredilla E, Palacio FJ, Pérez-Ferrer A, Alonso E, Gimeno M, Gilsanz F. Syringomyelia, neuropathic pain and Caesarean section. In conclusion, ACM I and its associated disorders pose Eur J Anaesthesiol 2004; 21: 669-70. anesthetic risks and the proper anesthetic management has not 11. Nel MR, Robson V, Robinson PN. Extradural anaesthesia for yet been established. A safe perioperative management of caesarean section in a patient with syringomyelia and Chiari type patients with ACM I can be achieved by careful attention to I anomaly. Br J Anaesth 1998; 80: 512-5.