Definite MMN
1. Weakness without objective sensory loss in the distribution of two or more named nerves; during the early stage, the finding of diffuse symmetric weakness rules out MMN
2. Definite conduction block in two or more sites outside common entrapment sites (defined as a decrease of more than 40 % in median or ulnar (not radial) CMAP area or 50 % or more in CMAP amplitude with an increase of less than 30 % in CMAP duration).
3. Normal sensory nerve conduction velocity across the sites with block.
4. Normal sensory nerve conductions for all nerves tested with a minimum of three tested.
5. Absent UMN signs including spastic tone, clonus, extensor plantars, and pseudobulbar palsy
Probable MMN
1. Weakness without objective sensory loss in the distribution of two or more named nerves; during the early stage, the finding of diffuse symmetric weakness rules out MMN
2. The presence of one of the following: probably conduction block in two or more sites outside common entrapment areas, or definite block in one segment and probable block in another outside common entrapment areas.
3. Normal sensory velocities outside the same areas with motor conduction block when study of the segment is technically feasible (ie. not required for segments proximal to the axilla or popliteal fossa).
4. Normal sensory nerve conductions for all nerves tested with a minimum of three tested.
5. Absent UMN signs including spastic tone, clonus, extensor plantars, and pseudobulbar palsy.
(as cited in NEJM 2007; 357:2710, adapted from Olney et al. Muscle Nerve 2003;27:117-121).
Tuesday, January 8, 2008
Sunday, January 6, 2008
Accessory neuropathy
1. Intracranially, a tumor such as a schwannoma or meningioma can cause .
2. In jugular foramen, the IX, X, XI nerve involvement is called " Vernet's syndrome" which is due, in order of frequency, to metastases, primary tumors such as schwannomas, an idiopathic syndrome with spontaneous recovery, and sarcoidosis.
3. In the neck, lymph node dissection in the posterior triangle remains the commonest cause, and may also affect the lesser occipital nerve. Other neck dissections, postoperative radiation, carotid endarterectomy, and cannulation of the IJ vein are also reported. Trauma to the posterior triangle from blunt injury, compression from wearing slings, hanging attempt- related injuries, stretch injuries from heavy lifting, glass or knife lacerations, tuberculosis of the cervical lymph nodes (scrofula) or idiopathic causes.
Presentation: Shoulder weakness and pain, and drooping of the shoulder. Trapezius wasting may occur. Paresthesias over the shoulder and scapula may occur.
Examination: Wasting of any part of the three parts of the trapezius. Scapular winging occurs at rest and with movement affecting the upper part of the scapula (v. the lower part with serratus anterior weakness). Shrugging of the shoulders is "worthless" because the levator scapulae (direct innervation from C3 and C4) can do this. Ask the patient to abduct the arms through 180 degrees from side to above the head, straight sideways. The second ninety degrees is accomplished by rotation of the scapula by the upper trapezius and cannot be accomplished otherwise. The middle trapezius is tested by asking the patient to lie prone, and abduct the arm at 90 degrees from the body. The middle trap can be palpated and the stability of the scapula can be assessed. The lower third is assessed with the patient prone, arms lying alongside head, lifting arms, and palpating the lower traps.
If the damage is proximal, the scm (sternocleidomastoid) is usually wasted. Its hard to assess the deltoid/rhomboid,spinati, and serratus anterior if scapula is not stabilized by the trapezius.
Evaluation-- EMG and NCS of the three parts of the trapezius separately. CT/MRI of base of skull/jugular foramen.
Management-- idiopathic-- none. Neck dissection-- may graft the greater auricular nerve. Surgical stabilization of scapula is better than orthotics which usually do not work. The levators and rhomboids can be transferred to scapula effectively. The procedure is effective but rarely done.
2. In jugular foramen, the IX, X, XI nerve involvement is called " Vernet's syndrome" which is due, in order of frequency, to metastases, primary tumors such as schwannomas, an idiopathic syndrome with spontaneous recovery, and sarcoidosis.
3. In the neck, lymph node dissection in the posterior triangle remains the commonest cause, and may also affect the lesser occipital nerve. Other neck dissections, postoperative radiation, carotid endarterectomy, and cannulation of the IJ vein are also reported. Trauma to the posterior triangle from blunt injury, compression from wearing slings, hanging attempt- related injuries, stretch injuries from heavy lifting, glass or knife lacerations, tuberculosis of the cervical lymph nodes (scrofula) or idiopathic causes.
Presentation: Shoulder weakness and pain, and drooping of the shoulder. Trapezius wasting may occur. Paresthesias over the shoulder and scapula may occur.
Examination: Wasting of any part of the three parts of the trapezius. Scapular winging occurs at rest and with movement affecting the upper part of the scapula (v. the lower part with serratus anterior weakness). Shrugging of the shoulders is "worthless" because the levator scapulae (direct innervation from C3 and C4) can do this. Ask the patient to abduct the arms through 180 degrees from side to above the head, straight sideways. The second ninety degrees is accomplished by rotation of the scapula by the upper trapezius and cannot be accomplished otherwise. The middle trapezius is tested by asking the patient to lie prone, and abduct the arm at 90 degrees from the body. The middle trap can be palpated and the stability of the scapula can be assessed. The lower third is assessed with the patient prone, arms lying alongside head, lifting arms, and palpating the lower traps.
If the damage is proximal, the scm (sternocleidomastoid) is usually wasted. Its hard to assess the deltoid/rhomboid,spinati, and serratus anterior if scapula is not stabilized by the trapezius.
Evaluation-- EMG and NCS of the three parts of the trapezius separately. CT/MRI of base of skull/jugular foramen.
Management-- idiopathic-- none. Neck dissection-- may graft the greater auricular nerve. Surgical stabilization of scapula is better than orthotics which usually do not work. The levators and rhomboids can be transferred to scapula effectively. The procedure is effective but rarely done.
Phrenic neuropathies
Causes:
Cervical spine-- motor neuron disease, poliomyelitis, herpes zoster
Neck-- stab wounds, surgery, anesthetic blocks in the brachial plexus; catheterization of internal jugular and subclavian veins, malignancy.
Chest-- thoracic surgery, mediastinal tumor, or irradiation
Uncertain-- Acute brachial neuropathy, diabetes mellitus, sarcoidosis, Guillian barre, idiopathic.
Muscle--NMJ -- acid maltase, polymyositis, myasthenia gravis
Pearls
1. Zoster is usually unilateral and asymptomatic, with herpetic lesions the tipoff and the chest X ray diagnostic.
2. Brachial plexus anesthesia blocks are usually temporary and asymptomatic, but bilateral blocks are not advisable due to risk of total diaphragm paralysis.
3. Metastases in the neck may also cause Horner's syndrome and the recurrent laryngeal nerve, causing vocal cord paralysis, and may be due to breast cancer.
4. The incidence during open heart surgery ranges from 10-85 % and may be due to ice slurry or topical cooling of heart during surgery. It occurs less often with an insulating pad, but may still occur after pericardiectomy or surgery for mediastinal tumors. In this situation it is often left sided. Bilateral injuries are rare but prolonged ventilator dependence is common.
5. In acute brachial plexopathy, 6 % have phrenic dyfunction and present with shoulder pain and dyspnea. Usually thoracic lesions are excluded and EMG and NCS are helpful.
6. Diabetic phrenic neuropathy is common and may account for the breathlessness of some diabetics.
Cervical spine-- motor neuron disease, poliomyelitis, herpes zoster
Neck-- stab wounds, surgery, anesthetic blocks in the brachial plexus; catheterization of internal jugular and subclavian veins, malignancy.
Chest-- thoracic surgery, mediastinal tumor, or irradiation
Uncertain-- Acute brachial neuropathy, diabetes mellitus, sarcoidosis, Guillian barre, idiopathic.
Muscle--NMJ -- acid maltase, polymyositis, myasthenia gravis
Pearls
1. Zoster is usually unilateral and asymptomatic, with herpetic lesions the tipoff and the chest X ray diagnostic.
2. Brachial plexus anesthesia blocks are usually temporary and asymptomatic, but bilateral blocks are not advisable due to risk of total diaphragm paralysis.
3. Metastases in the neck may also cause Horner's syndrome and the recurrent laryngeal nerve, causing vocal cord paralysis, and may be due to breast cancer.
4. The incidence during open heart surgery ranges from 10-85 % and may be due to ice slurry or topical cooling of heart during surgery. It occurs less often with an insulating pad, but may still occur after pericardiectomy or surgery for mediastinal tumors. In this situation it is often left sided. Bilateral injuries are rare but prolonged ventilator dependence is common.
5. In acute brachial plexopathy, 6 % have phrenic dyfunction and present with shoulder pain and dyspnea. Usually thoracic lesions are excluded and EMG and NCS are helpful.
6. Diabetic phrenic neuropathy is common and may account for the breathlessness of some diabetics.
Other high cervical and related disorders
1. Neck-tongue syndrome is due to compression of the C2 ventral ramus. There may be neck pain, occipital numbness, and tongue paresthesias on turning the head. Some patients have congenital abnormalities of the cervical spine.
2. Third occipital headache may have occipital and suboccipital pain. It is a postwhiplash injury headache with temporary and partial relief with nerve blocks. It probably is due to degenerative arthritis of the C2-3 facet joint and is not neurologic in origin.
3. Greater auricular nerve damage is commonly caused by surgery to the neck and face, especially rhytidectomy (face-lift) with numbness around the ear and later, painful neuromas. CEA, parotid surgery, and leprosy can be causative. NERVE CONDUCTIONS CAN BE CONFIRMATORY.
4. Lesser occipital nerve injury occurs during lymph node dissection in the neck (also gets the accessory nerve). The presentation is numbness behind the ear.
2. Third occipital headache may have occipital and suboccipital pain. It is a postwhiplash injury headache with temporary and partial relief with nerve blocks. It probably is due to degenerative arthritis of the C2-3 facet joint and is not neurologic in origin.
3. Greater auricular nerve damage is commonly caused by surgery to the neck and face, especially rhytidectomy (face-lift) with numbness around the ear and later, painful neuromas. CEA, parotid surgery, and leprosy can be causative. NERVE CONDUCTIONS CAN BE CONFIRMATORY.
4. Lesser occipital nerve injury occurs during lymph node dissection in the neck (also gets the accessory nerve). The presentation is numbness behind the ear.
Disorders of the cervical plexus
1. Radiculopathies usually involve C6-7 (see cervical radiculopathies); rarely the C3-4 nerve root foramen is affected with compression of the C4 root. Symptoms are pain and paresthesias in the ear region with sensory loss.
2. The cervical plexus is vulnerable in traction injuries such as motorcycle injuries that also affect the upper trunk of the brachial plexus, and during surgery of carotids (endarterectomy) or radical dissection of the neck. Motor dysfunction other than phrenic injury is hard to detect. Sensory loss in the upper cervical regions is common.
3. Herpes zoster is common in C2 and C3 dorsal root ganglia. Both zosteriform eruptions and postherpetic neuralgia may occur.
4.C2 ganglionopathy/radiculopathy and greater occipital neuropathy (avoid term occipital neuralgia, and cervicogenic headache, and whiplash injury) presents with deep stabbing unilateral pain in the neck and back of the head, with hyper/hypesthesia of scalp and tenderness of the nerve. It is caused by trauma (whiplash), spondylosis, ligamentous entrapment, zoster, neurofibroma (dorsal ramus), and trauma/compression of the GON. "the cardinal symptom is intermittent or continuous numbness or paresthesias (with or without pain) in C2 dermatome. The C2 nerve may be tender to palpate, or patients may have vertigo. Some cases may require surgical exploration.
C2 nerve root is rarely involved in major fracture/dislocation, congenital abnormalities of the cervical spine, , subluxation of the atlas on the axis joint to to rheumatoid arthritis, or bone softening disorders such as Paget's disease, osteogenita imperfecta, and osteomalacia. Whiplash may be a cause but is probably vastly overstated.
Treatment including analgesics and acolar may or may not help, as may injections of anesthetics or corticosteroids. Surgery may reveal severe facet disease, ligamentous entrapment of a ganglion. Procedures may include C2 ganglionectomy or partial sectioning of the C1-3 rootlets.
5. The diversity of causes of "cervicogenic headache" make reports of definitive treatment difficult to evaluate.
2. The cervical plexus is vulnerable in traction injuries such as motorcycle injuries that also affect the upper trunk of the brachial plexus, and during surgery of carotids (endarterectomy) or radical dissection of the neck. Motor dysfunction other than phrenic injury is hard to detect. Sensory loss in the upper cervical regions is common.
3. Herpes zoster is common in C2 and C3 dorsal root ganglia. Both zosteriform eruptions and postherpetic neuralgia may occur.
4.C2 ganglionopathy/radiculopathy and greater occipital neuropathy (avoid term occipital neuralgia, and cervicogenic headache, and whiplash injury) presents with deep stabbing unilateral pain in the neck and back of the head, with hyper/hypesthesia of scalp and tenderness of the nerve. It is caused by trauma (whiplash), spondylosis, ligamentous entrapment, zoster, neurofibroma (dorsal ramus), and trauma/compression of the GON. "the cardinal symptom is intermittent or continuous numbness or paresthesias (with or without pain) in C2 dermatome. The C2 nerve may be tender to palpate, or patients may have vertigo. Some cases may require surgical exploration.
C2 nerve root is rarely involved in major fracture/dislocation, congenital abnormalities of the cervical spine, , subluxation of the atlas on the axis joint to to rheumatoid arthritis, or bone softening disorders such as Paget's disease, osteogenita imperfecta, and osteomalacia. Whiplash may be a cause but is probably vastly overstated.
Treatment including analgesics and acolar may or may not help, as may injections of anesthetics or corticosteroids. Surgery may reveal severe facet disease, ligamentous entrapment of a ganglion. Procedures may include C2 ganglionectomy or partial sectioning of the C1-3 rootlets.
5. The diversity of causes of "cervicogenic headache" make reports of definitive treatment difficult to evaluate.
Cervical spinal nerves-- special anatomic aspects to consider
1. The ventral rami of C1-C4 form the cervical plexus, and C5-C8 the brachial plexus.
2. Exceptionally, C1 spinal nerve divides WITHIN the spinal canal to form a ventral and dorsal ramus, that passes above the arch of C1 to supply the deep muscles of the neck, without sensory fibers. The ventral ramus joins the cervical plexus.
3. The C2 root is very short. The ventral ramus joins the cervical plexus. C2 may project to the brow, whereas pain the back of the head is more likely cervical plexus. The dorsal ramus passes between C1 and C2 and the larger medial branch becomes the greater occipital nerve (C2 dorsal ramus). The lateral branch subserves the paraspinal muscles. That supplies the back of the head. C3,4,5, T1 dorsal rami affect skin on back of the neck.
4. The four cutaneous branches are the greater auricular, lesser occipital, supraclavicular, and transverse cutaneous nerves of the neck. They all emerge from the posterior border of the sternocleidomastoid muscle into the posterior triangle of the neck.
Lesser occipital nerve (C2-3 ventral ramus) affects the skin behind the ear. It affects the lower posterior occiput whereas the greater occipital affects anteriorly.
The greater auricular nerve (C2-3 ventral ramus) affects the skin below and directly behind the ear. Preauricular nerve overlaps trigeminal distribution, pain is dull aching not lancination. Posterior auricular nerve innervates the posterior occiput, mastoid, most of the pinna and posterior parietal area.
The transverse cutaneous nerve (C2-3 ventral ramus) of the neck affects the skin of the neck.
The supraclavicular nerve (C3-4 ventral ramus)affects the skin on top of the shoulder.
5. The phrenic nerve (C5) is the major muscular branch of the cervical plexus.
6. The spinal root of the accessory nerve derives from anterior horn cells and ascends the cord through the foramen magnum and leaves it throught the jugular foramen, together with the IX and X cranial nerves.
More pearls:
1. TMJ and cervical plexus pain may coexist in young patients due to cervical plexus
2. Difficulty swallowing ("pain stuck in my throat") may be due to spasm of cricopharyngeus muscle (external esophageal sphincter) and dyssynergia of posterior pharyngeal muscles (X nerve) that pushes the bolus to the cricopoharyngeus muscle that fails to open rapidly enough.
2. Exceptionally, C1 spinal nerve divides WITHIN the spinal canal to form a ventral and dorsal ramus, that passes above the arch of C1 to supply the deep muscles of the neck, without sensory fibers. The ventral ramus joins the cervical plexus.
3. The C2 root is very short. The ventral ramus joins the cervical plexus. C2 may project to the brow, whereas pain the back of the head is more likely cervical plexus. The dorsal ramus passes between C1 and C2 and the larger medial branch becomes the greater occipital nerve (C2 dorsal ramus). The lateral branch subserves the paraspinal muscles. That supplies the back of the head. C3,4,5, T1 dorsal rami affect skin on back of the neck.
4. The four cutaneous branches are the greater auricular, lesser occipital, supraclavicular, and transverse cutaneous nerves of the neck. They all emerge from the posterior border of the sternocleidomastoid muscle into the posterior triangle of the neck.
Lesser occipital nerve (C2-3 ventral ramus) affects the skin behind the ear. It affects the lower posterior occiput whereas the greater occipital affects anteriorly.
The greater auricular nerve (C2-3 ventral ramus) affects the skin below and directly behind the ear. Preauricular nerve overlaps trigeminal distribution, pain is dull aching not lancination. Posterior auricular nerve innervates the posterior occiput, mastoid, most of the pinna and posterior parietal area.
The transverse cutaneous nerve (C2-3 ventral ramus) of the neck affects the skin of the neck.
The supraclavicular nerve (C3-4 ventral ramus)affects the skin on top of the shoulder.
5. The phrenic nerve (C5) is the major muscular branch of the cervical plexus.
6. The spinal root of the accessory nerve derives from anterior horn cells and ascends the cord through the foramen magnum and leaves it throught the jugular foramen, together with the IX and X cranial nerves.
More pearls:
1. TMJ and cervical plexus pain may coexist in young patients due to cervical plexus
2. Difficulty swallowing ("pain stuck in my throat") may be due to spasm of cricopharyngeus muscle (external esophageal sphincter) and dyssynergia of posterior pharyngeal muscles (X nerve) that pushes the bolus to the cricopoharyngeus muscle that fails to open rapidly enough.
EMG physical examination PEARLS
1. The lack of atrophy in a weak muscle indicates either an upper motor neuron lesion or purely demyelinating lesion and may represent spurious weakness.
2. The lack of weakness may be due to confusion, inattention, uncooperativeness, PAIN, feigning or a somatization disorder.
3. Fasciculations may be present in radiculopathies or other focal neuropathies as well as in disorders of the anterior horn.
4. Examination of the tendon reflexes is more objective than muscle power or sensory testing.
Sensory testing pearls:
1. Hyperesthesia, allodynia or hyperpathia are possible as well as hypesthesia.
2. The distribution of sensory loss is usually partial, often in the distal part of the dermatome,eg. the fingertips only in carpal tunnel syndrome. This may be due to damage only to selected fascicles within a proximal part of the nerve (ie. the lesion need not be distal).
Anatomic pitfalls: dermatome and myotome variations
1. Tibialis anterior, in root stimulation studies, is innervated by L4 75 % of the time, not L5.
2. EDB (in foot) can be L5 or S1 even more variably.
3. Dermatomal maps are based on flimsy anatomic evidence.
2. The lack of weakness may be due to confusion, inattention, uncooperativeness, PAIN, feigning or a somatization disorder.
3. Fasciculations may be present in radiculopathies or other focal neuropathies as well as in disorders of the anterior horn.
4. Examination of the tendon reflexes is more objective than muscle power or sensory testing.
Sensory testing pearls:
1. Hyperesthesia, allodynia or hyperpathia are possible as well as hypesthesia.
2. The distribution of sensory loss is usually partial, often in the distal part of the dermatome,eg. the fingertips only in carpal tunnel syndrome. This may be due to damage only to selected fascicles within a proximal part of the nerve (ie. the lesion need not be distal).
Anatomic pitfalls: dermatome and myotome variations
1. Tibialis anterior, in root stimulation studies, is innervated by L4 75 % of the time, not L5.
2. EDB (in foot) can be L5 or S1 even more variably.
3. Dermatomal maps are based on flimsy anatomic evidence.
Hemorrage into or around nerves
1. Patients on anticoagulation or with bleeding disorders develop hematomas that compress nerves.
2. Hemorrhage into nerves occurs particularly in patients with bleeding disorders, including leukemia, hemophilia and thrombocytopenia
3. Acute stretch injuries may rupture an intraneural blood vessel and cause bleeding into a nerve. For example, the common peroneal nerve in popliteal fossa may be affected after a severe inversion injury of the ankle.
2. Hemorrhage into nerves occurs particularly in patients with bleeding disorders, including leukemia, hemophilia and thrombocytopenia
3. Acute stretch injuries may rupture an intraneural blood vessel and cause bleeding into a nerve. For example, the common peroneal nerve in popliteal fossa may be affected after a severe inversion injury of the ankle.
Injection Injuries into nerves
Mechanism
1. injection injury of nerve
2. Hematoma or hemorrhage around injection site (hours later)
3. Scarring around injection site (weeks later).
1. injection injury of nerve
2. Hematoma or hemorrhage around injection site (hours later)
3. Scarring around injection site (weeks later).
Metastases to the peripheral nerves
1. These are rare and occur with lymphoma and leukemia. It may be due to spread rather than metastasis per se.
2. Compression of peripheral nerves is much more common, eg. brachial plexopathy and lumbar plexopathy.
3. Hemorrhage into the nerve is another possible mechanism.
4. Presentation can include mononeuropathy multiplex, radiculopathy, mononeuropathy, and polyneuropathy.
5. Paraneoplastic syndromes of the peripheral nerves are described.
2. Compression of peripheral nerves is much more common, eg. brachial plexopathy and lumbar plexopathy.
3. Hemorrhage into the nerve is another possible mechanism.
4. Presentation can include mononeuropathy multiplex, radiculopathy, mononeuropathy, and polyneuropathy.
5. Paraneoplastic syndromes of the peripheral nerves are described.
Malignant peripheral nerve sheath tumors (MPNST) Pearls
1. Term includes malignant schwannoma and neurogenic sarcoma
2. In NF-1 MPNST's can occur (2-16 % of patients with NF-1 develop one over their lifetime), or they can occur sporadically, or post-radiation.
3. Occassionally a previously existing benign neurofibroma can transform and become malignant.
4. They are located in the same areas as solitary and plexiform neurofibromas.
5. Pain and nerve dysfunction are greater than in benign tumors.
6. The tumors can become large before being detected.
7. Therapy involves amputation, radiation, chemotherapy.
8. The prognosis is poor with local recurrences and metastases to the lungs.
2. In NF-1 MPNST's can occur (2-16 % of patients with NF-1 develop one over their lifetime), or they can occur sporadically, or post-radiation.
3. Occassionally a previously existing benign neurofibroma can transform and become malignant.
4. They are located in the same areas as solitary and plexiform neurofibromas.
5. Pain and nerve dysfunction are greater than in benign tumors.
6. The tumors can become large before being detected.
7. Therapy involves amputation, radiation, chemotherapy.
8. The prognosis is poor with local recurrences and metastases to the lungs.
Other benign peripheral nerve tumors
1. Besides schwannomas and neurofibromas, other types are rare.
2. The fibrolipoma is a rare fatty tumor that presents as a swelling often in the median nerve, causing motor and sensory symptoms.
3. The intraneural perineuroma (aka hypertrophic neuropathy) usually involves a single peripheral nerve and causes painless but slowly progressive wasting and weakness, with mild or no sensory loss.
4. Non-nerve sheath tumors include: ganglion cysts, hypertrophic neuropathy, lipomas, hemangiomas, and desmoid tumors. Metastases to nerves can also occur (would be classified as malignant though)
2. The fibrolipoma is a rare fatty tumor that presents as a swelling often in the median nerve, causing motor and sensory symptoms.
3. The intraneural perineuroma (aka hypertrophic neuropathy) usually involves a single peripheral nerve and causes painless but slowly progressive wasting and weakness, with mild or no sensory loss.
4. Non-nerve sheath tumors include: ganglion cysts, hypertrophic neuropathy, lipomas, hemangiomas, and desmoid tumors. Metastases to nerves can also occur (would be classified as malignant though)
Peripheral neurofibromas pearls
1. Solitary NF's in otherwise healthy patients (ie. , those without NF-1) may be painless or painful subcutaneous swelling without neurologic features, unless they arise from a major nerve trunk or plexus in which case they may have motor and sensory dysfunction.
2. Multiple neurfibromas such as seen in NF-1 do not transform and are a cardinal feature of NF-1.
3. Plexiform neurofibromas arise from deeply situated nerves and can be very damaging but are highly prevalent in NF-1; in one study 35 % of patients had them in the abdomen and pelvis and four percent in chest and supraclavicular areas. Surgical results for plexiform neurofibromas are not nearly as good as solitary type.
4. In patients without NF-1, spinal tumors are usually schwannomas.
2. Multiple neurfibromas such as seen in NF-1 do not transform and are a cardinal feature of NF-1.
3. Plexiform neurofibromas arise from deeply situated nerves and can be very damaging but are highly prevalent in NF-1; in one study 35 % of patients had them in the abdomen and pelvis and four percent in chest and supraclavicular areas. Surgical results for plexiform neurofibromas are not nearly as good as solitary type.
4. In patients without NF-1, spinal tumors are usually schwannomas.
Schwannoma of the peripheral nerve (benign)
Pearls
1. The most common peripheral nerve tumors occur in any peripheral nerve but especially the spinal nerves, peroneal nerve, ulnar nerve, sympathetic nerves and vagus nerves.
2. In a peripheral nerve the presentation is that of a mass that is often painless with paresthesias and positive Tinel's sign over the nerve. The exception of greater findings occurs if the nerve is in a restricted space such as carpal or fibular tunnel.
3. Schwannomas of deep nerves such as sciatic are difficult to detect.
4. Scwannomas that arise from spinal or sympathetic nerves may extend into and compress the spinal cord.
5. Multiple schwannomas occur primarily but not exclusively in NF-2.
6. 62% neurofibromas, 38% schwannomas
In schannomas function preserved in 89% after resection
1. The most common peripheral nerve tumors occur in any peripheral nerve but especially the spinal nerves, peroneal nerve, ulnar nerve, sympathetic nerves and vagus nerves.
2. In a peripheral nerve the presentation is that of a mass that is often painless with paresthesias and positive Tinel's sign over the nerve. The exception of greater findings occurs if the nerve is in a restricted space such as carpal or fibular tunnel.
3. Schwannomas of deep nerves such as sciatic are difficult to detect.
4. Scwannomas that arise from spinal or sympathetic nerves may extend into and compress the spinal cord.
5. Multiple schwannomas occur primarily but not exclusively in NF-2.
6. 62% neurofibromas, 38% schwannomas
In schannomas function preserved in 89% after resection
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