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certification.
Posttraumatic epilepsy is a major concern following traumatic brain injury. The presence of blood
(hence iron) in the brain parenchyma is thought to play an aetiological role in the development of
posttraumatic epilepsy. Simple uncomplicated epidural haematoma without parenchymal blood might
allow medical certification following a one to two year observation period. Subdural haematoma is often
associated with underlying cortical contusion, increasing risk of posttraumatic epilepsy. Significant risk
is present in the first two years post injury, though it declines with time. Medical certification may be
appropriate after two years. With intraparenchymal haematoma, a two year period of observation is
warranted due to the presence of parenchymal blood. Seizure risk also exists with diffuse axonal injury,
and a period of one to two years of observation is appropriate.
In some individuals with severe injury, perhaps including intracranial haematoma, focal neurological
deficit, and cognitive impairment, medical certification may yet be possible after eventual recovery. In
such cases, however, an observation period up to five years may be appropriate.
NEOPLASMS
Intracranial neoplasms are not rare and will be encountered in the licence holder population. Neurological
symptoms may include headaches and vomiting related to increased intracranial pressure, seizures, focal
neurological deficit related to mass effect or infiltration, cognitive changes, and visual field defects
related to pituitary neoplasms.
ICAO Preliminary Unedited Version — October 2008 III-10-13
Benign Neoplasms
Benign intracranial neoplasms may involve the dura mater, cranial nerves, or brain parenchyma.
Extraparenchymal tumours include meningioma, neurofibroma, acoustic neuroma (Schwannoma9) and
pituitary adenoma. Benign parenchymal growths include ependymoma, choroid plexus papilloma, and
colloid cyst (considered a cyst rather than a neoplasm).Though craniopharyngiomas are benign, they may
invade adjacent neural tissue and are subject to recurrence.
If complete excision can be accomplished, the licence holder may be cured and thus eligible for medical
certification. At times there may be residual neoplastic tissue, since complete excision carries the risk of
creating a neurological deficit. In such instances, medical certification may be possible, conditional upon
satisfactory follow-up with serial imaging studies and current status reports.
Operational limitations:
The presence of a benign intracranial neoplasm is disqualifying for all classes of medical certification.
Aeromedical considerations:
Successful removal of a benign intracranial neoplasm with uneventful recovery will allow medical
certification following one year of observation, primarily related to seizure risk. Posterior fossa
neoplasms, which characteristically do not lead to seizures, are an exception. Ordinarily limitations have
to be imposed, with certification being conditional on periodic evaluation for tumour recurrence.
Malignant Neoplasms
Malignant glial neoplasms, including astrocytomas and oligodendrogliomas, characteristically have
invasive qualities without distinct boundaries. The interdigitation of neoplastic with normal neuronal
tissue precludes complete resection, and thus a “debulking” surgical procedure is commonly employed.
Eventual recurrence is the rule, though with low grade glial neoplasms this may occur indolently over
many years. Seizures are a risk, and subtle neurological impairment depending upon location is an
additional concern. These features ordinarily preclude medical certification, though some cases of cure
appear in the literature.
Operational implications:
Malignant intracranial neoplasms are disqualifying for all classes of medical certification due to risk of
sudden or insidious incapacitation.
Aeromedical considerations:
Malignant parenchymal neoplasms may be debulked by surgical measures, but neoplastic cells
characteristically remain and recurrence is the rule. A permanent bar from certification is therefore
warranted. There may be very rare exceptions following a long recurrence free and symptom free interval
(e.g. ten years).
9 Schwannoma: a neoplasm originating from the Schwann cells (of the myelin sheath) of neurons. After Theodor
Schwann, German anatomist and physiologist (1810-1882)
ICAO Preliminary Unedited Version — October 2008 III-10-14
HEREDITARY, DEGENERATIVE, AND DEMYELINATING DISORDERS
Certain neurological conditions follow a benign course for many years, causing no significant concern for
aviation safety. Others follow a slowly progressive temporal profile, lending themselves to monitoring
measures that can identify the point of compromise to flight safety.
　
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本文鏈接地址：Manual of Civil Aviation Medicine 2(31)