What are the anaesthetic implications for a patient with neurofibroma?

Anaesthetic Implications for Patients with Neurofibromatosis

Patients with neurofibromatosis require meticulous preoperative airway assessment and consideration of awake fiberoptic intubation when airway compromise is suspected, as neurofibromas can cause life-threatening upper airway obstruction at induction. 1, 2

Critical Preoperative Assessment

Airway Evaluation

• Systematically evaluate for neurofibromas involving the airway, including the tongue base, larynx, and trachea, as these can cause complete airway obstruction at induction 2
• Obtain preoperative imaging (CT or MRI) of the head, neck, and chest when airway involvement is suspected to identify tumor location and extent 1, 3
• Look specifically for cervical masses that may cause difficult positioning, cervical instability, or airway compression 1
• Emergency cricothyroidotomy equipment must be immediately available, as standard airway management may fail catastrophically 2

Neuraxial Considerations

• Preanesthesia neuraxial imaging to evaluate for spinal or paraspinal neurofibromas is probably not needed for routine epidural or spinal anesthesia 4
• If concerns exist about spinal neurofibromas, spinal anesthesia may be considered over epidural 4
• No significant adverse events have been reported in the literature for women with NF1 undergoing epidural anesthesia 4

Cardiovascular Screening

• Measure blood pressure preoperatively to screen for pheochromocytoma, which can cause intraoperative hypertensive crises 4, 5, 6
• Assess for symptoms of pheochromocytoma including diaphoresis, palpitations, and paroxysmal hypertension 5, 7
• Evaluate for renovascular disease, which is more common in NF1 patients 6

Intraoperative Management

Airway Management Strategy

• Perform awake fiberoptic intubation with topical airway anesthesia and low-dose remifentanil (0.05 mcg/kg/min) when difficult airway is anticipated 1
• Avoid general anesthesia induction before securing the airway in patients with suspected airway neurofibromas 1, 2
• Consider video laryngoscopy for improved visualization, particularly in patients requiring non-standard positioning due to large tumors 8
• Maintain spontaneous ventilation until airway is definitively secured 1, 2

Hemorrhage Preparedness

• Anticipate significant blood loss during tumor resection, particularly for large plexiform neurofibromas or those near major vessels 1
• Have blood products (red blood cells and plasma) immediately available, as inadvertent vascular injury can occur during tumor manipulation 1
• Prepare vasopressor support (norepinephrine) for hemodynamic instability 1

Positioning Considerations

• Large neurofibromas may necessitate lateral or modified positioning rather than standard supine positioning 8
• Assess positioning limitations preoperatively and communicate with surgical team 1, 8

Special Perioperative Concerns

Malignant Transformation Risk

• Maintain high suspicion for malignant peripheral nerve sheath tumor (MPNST) in patients presenting with progressive severe pain, rapid tumor growth, or new neurologic symptoms 5, 7, 6
• Approximately 8-13% of plexiform neurofibromas undergo malignant transformation to MPNST 5
• Ensure tissue is sent for histopathological examination, as preoperative imaging cannot reliably distinguish benign from malignant lesions 1, 9

Pain Management

• Chronic pain affects the majority of NF1 adults and requires multimodal analgesia planning 5, 7
• Consider regional anesthesia techniques when anatomically feasible and not contraindicated by tumor location 4
• Plan for adequate postoperative pain control, as these patients often have baseline chronic pain 5, 7

Common Pitfalls to Avoid

• Never induce general anesthesia without securing the airway first in patients with suspected airway neurofibromas—this can be fatal 2
• Do not assume epidural anesthesia is contraindicated; it appears safe in NF1 patients without specific spinal involvement 4
• Avoid underestimating blood loss potential during tumor resection near major vessels 1
• Do not overlook cardiovascular screening for pheochromocytoma, which can cause severe intraoperative complications 4, 5