| disease | Primary Intraspinal Tumors |
Intraspinal tumors refer to primary and metastatic tumors that grow within the spinal cord itself and in the tissues adjacent to the spinal cord within the spinal canal (such as nerve roots, dura mater, adipose tissue in the spinal canal, blood vessels, etc.). Clinically, based on the positional relationship between the tumor and the spinal cord or dura mater, intraspinal tumors are generally classified into three categories: intramedullary, intradural extramedullary, and extradural. Intradural extramedullary tumors are the most common, followed by extradural tumors, while intramedullary tumors are the least common. Intramedullary tumors account for 9–18%, intradural extramedullary tumors for about 55%, extradural tumors for about 25%, and dumbbell-shaped intraspinal tumors for approximately 8.5%.
bubble_chart Epidemiology
The annual incidence of primary intraspinal tumors is approximately 0.9 to 2.5 per 100,000 people. The incidence of primary tumors in the cervical spinal canal accounts for about 23% of all primary intraspinal tumors. The adult cervical spinal cord is approximately 10 cm long, constituting 23% of the total length of the spinal cord. The likelihood of spinal cord tumors occurring in the cervical, thoracic, or lumbar segments is similar to the number of vertebral segments in each region. Multiple spinal cord tumors account for only 1% of cases and are often associated with neurofibromatosis.
Intraspinal tumors can occur at any age, with the majority of cases occurring in adults aged 20 to 40. Primary intraspinal tumors are slightly more common in males than females, though some believe there is no significant gender difference.
bubble_chart EtiologyThe factors influencing pathological changes in spinal cord compression mainly include:
1. **Related to the location of tumor compression and the nature of neural tissue structure**: Different spinal nerve tissues vary in their tolerance to pressure. For example, tumors initially irritate nerve roots before causing damage; gray matter has greater tolerance to tumor compression than white matter. In white matter, the pyramidal tracts and nerve fibers transmitting proprioception and touch are thicker (5μm–21μm in diameter), while pain fibers are thinner (less than 2μm in diameter). Under compression, thin fibers exhibit greater tolerance than thick fibers and recover faster after decompression. Generally, in the early stages of compression, nerve roots are stretched, and the spinal cord shifts. Later, it becomes deformed under pressure, eventually leading to degeneration and progressive neurological dysfunction.
2. **Impact of tumors on spinal cord blood circulation**: Compression of veins leads to venous dilation, static blood, and edema. When the **stirred pulse** is compressed, the affected area suffers from insufficient blood supply, hypoxia, and nutritional disturbances, causing spinal cord degeneration and softening, ultimately leading to necrosis. In terms of ischemic tolerance, gray matter outperforms white matter, and thin nerve fibers surpass thick ones. Reports indicate intraoperative observations of a bluish dorsal spinal cord surface, enlarged **stirred pulse**, and significantly absent draining veins, though microscopic examination reveals a few small nourishing **stirred pulses**.
The course of intraspinal tumors is generally over one year. The shortest reported symptom duration is 17 days, while the longest is 12 years. Intramedullary tumors average 11.6 months, whereas extramedullary tumors average 19.2 months.
3. **The hardness of the tumor is closely related to its degree of harm to the spinal cord**: Soft tumors, especially slow-growing ones, allow the spinal cord sufficient time to adjust its blood circulation, resulting in slower progression, milder symptoms, and faster, more complete postoperative recovery. Hard tumors, even if small, can easily embed into the spinal cord, where any spinal movement may cause **contusion** and glial hyperplasia, often leading to suboptimal postoperative recovery.4. **Related to the tumor’s growth pattern and speed**: Some intramedullary tumors grow primarily by expansion, while others grow invasively—the latter causing greater damage to the spinal cord. Slow-growing tumors, even with significant spinal cord compression, may present mild symptoms due to the spinal cord’s compensatory capacity. Conversely, rapidly growing tumors, especially malignant ones, are prone to causing acute, complete transverse spinal cord damage, necessitating emergency surgery to relieve compression. Even a delay of 1–2 hours can often lead to severe consequences.
bubble_chart Pathological Changes
According to pathology, spinal canal tumors can be classified into: meningioma, schwannoma, astrocytoma, ganglioneuroma, plasmacytoma, simple cyst, hemangioma, lipoma, hamartoma, spinal meningeal cyst, mesenchymoma, enterogenous cyst, malignant schwannoma, and malignant hemangioendothelioma. Neurofibroma, meningioma, and gliomas (including astrocytoma and ependymoma) are the most common pathological types. Neurofibroma accounts for approximately 40.0%, meningioma accounts for about 9–12%, and gliomas account for about 8–12%.
bubble_chart Clinical Manifestations
When the spinal cord is compressed, motor dysfunction precedes sensory dysfunction. Additionally, factors such as impaired blood circulation, cerebrospinal fluid dynamics disorders, and concurrent inflammation and adhesions may accompany spinal tissue compression. Therefore, the clinical manifestations are diverse and complex. Generally, the progression of symptoms caused by extradural tumors is divided into the late stage [third stage]: (1) Early compression stage: radicular pain; (2) Progressive compression stage: Brown-Sequard syndrome; (3) Complete spinal cord compression stage: transverse spinal cord injury. This classification remains the basis for current clinical categorization.The clinical symptoms of extradural tumors typically manifest in three stages.
Cervical spinal nerve irritation stage (radicular pain stage): In the early stage of the disease, the primary manifestation is irritation symptoms of the corresponding structures, with the most common symptom being neuralgia. The pain often spreads along the distribution area of the nerve roots and is mostly paroxysmal. Activities such as coughing, sneezing, or straining during bowel movements can exacerbate the pain. "Night pain and pain in the supine position" are characteristic symptoms of spinal canal tumors. Additionally, abnormal skin sensations such as numbness or burning may occur. If the tumor compresses from the ventral side, it may initially present with muscle twitching, tremors, or weakness in the muscles innervated by the compressed segment or segments below. Radicular pain is the initial symptom in 54% of intraspinal tumors (with schwannomas being the most common, accounting for 60.8% of radicular pain cases), manifesting as neck and shoulder pain. Night pain occurs in 35% of cases. The initial symptom of nerve tract compression occurs in 45.9% of cases, presenting as sensory, motor, and autonomic dysfunction below the level of compression.
Cervical spinal cord partial compression stage: As the tumor grows, symptoms of spinal cord tract compression gradually appear on top of existing symptoms. For example, compression of the spinothalamic tract may lead to decreased or lost pain and temperature sensation below the contralateral side of the lesion. Compression of the posterior column may result in decreased deep sensation. Involvement of the motor tracts may cause upper motor neuron paralysis in the ipsilateral limbs below the lesion level. Brown-Sequard syndrome is a specific symptom of intraspinal extradural tumors, though it is often atypical. Ni Bin et al. reported 137 cases of intraspinal tumors, with 102 cases showing ascending paralysis (74 of which were extradural tumors) and 10 cases showing descending paralysis (8 of which were intramedullary tumors). There were also 4 cases of Brown-Sequard syndrome.
Cervical spinal cord complete compression stage: As the disease progresses, the spinal cord undergoes transverse damage, and the pathological changes become irreversible. Below the lesion level, limb movement and sensation are lost, accompanied by autonomic dysfunction and impaired bladder and bowel function, marking the advanced stage of paraplegia.
Clinical characteristics of tumors in different locations within the spinal canal:
Extradural tumors: Common primary tumors in the cervical region include meningiomas, neurofibromas, chordomas, epidermoid cysts, hemangiomas, and lipomas. Their clinical features include:
1. More common in middle-aged and older patients.
2. Symptoms vary with tumor type, often including spinal pain, and radicular pain can be severe.
3. Some tumors may grow in a dumbbell shape, protruding outside the spinal canal and exhibiting characteristics of extrinsic tumors.
4. Compression of the cervical spinal cord resembles that of intradural extramedullary tumors.
Intradural extramedullary tumors:
1. More common in the cervical region.
2. Neurofibromas and meningiomas are predominant. Neurofibromas grow on spinal nerve roots, often the posterior roots, making radicular pain common. These tumors may extend through the intervertebral foramen, forming dumbbell-shaped tumors, with X-rays showing enlarged intervertebral foramina.
3. When extramedullary lesions compress the spinal cord, symptoms typically progress from the lower to upper levels due to the layered arrangement of sensory and motor tracts.
4. Since these tumors grow in the subarachnoid space, spinal canal obstruction occurs earlier, and cerebrospinal fluid protein levels rise significantly.
5. These tumors grow slowly, with病程 lasting up to 10 years in some cases.
Intramedullary tumor Clinical features of intraosseous tumors:
1. Gliomas are the most common, accounting for 80%, with ependymomas being the predominant type.
2. The tumor invades the gray matter and has a tendency to grow vertically.
3. The tumor involves the spinal cord gray matter, leading to signs of corresponding structural damage, such as sensory disturbances, dissociated sensory loss, or muscle atrophy.
4. Spinal canal obstruction occurs relatively late.
Clinical Features of Intraspinal Tumors at Different Levels
Medulla Oblongata and Upper Cervical Spinal Canal Tumors: These refer to tumors occurring in tissues such as the medulla oblongata, spinal cord, nerve roots, and meninges above the level of the third cervical vertebra. More than half are located in the space from the foramen magnum of the occipital bone to the first cervical vertebra, hence also termed foramen magnum region tumors. They can be classified into descending, extramedullary, and intramedullary types. The first two types are mostly gliomas, commonly seen in adolescents. The extramedullary type is almost always benign, primarily consisting of neurofibromas and meningiomas, and is more common in middle-aged individuals.
The main clinical symptoms of tumors in this region include:
1. Radiating pain in the neck and occipital region, sensory减退 in the posterior occipital area, tenderness in the neck and occipital region, neck stiffness, forced head position, finger numbness, and muscle fasciculations in the limbs;
2. Symptoms of medulla oblongata and cervical spinal cord damage: Common, including pyramidal tract signs, spinothalamic tract signs, sphincter dysfunction, and atrophy of small muscles in the upper limbs;
3. Symptoms of posterior cranial nerve damage: Rare, including disturbances in facial sensation, corneal reflex, hearing, masticatory muscle function, tongue muscle function, pharyngeal reflex, vocalization, shoulder shrugging, and head turning;
4. Symptoms of cerebellar damage: Rare, including reduced muscle tone,迟钝 tendon reflexes,眼球 tremor, and ataxia;
5. Except for the descending type, which can produce symptoms of increased intracranial pressure early on, other types generally do not cause significant intracranial hypertension.
Middle and Lower Cervical Spinal Canal Tumors: Because the病变 is located precisely in the cervical enlargement, the clinical manifestations are more突出 with segmental or radicular symptoms. Tumors often present with radicular pain. The affected upper limb may exhibit muscle atrophy and weakened tendon reflexes. If the pyramidal tract is受损, upper motor neuron paralysis may occur in the affected or both sides of the四肢. The more common sequence of occurrence is the affected upper limb → affected lower limb → contralateral lower limb → contralateral upper limb. This is because the tumor first compresses the anterior horn of the spinal cord or the anterior nerve roots, causing flaccid paralysis in the ipsilateral upper limb. As the tumor progresses, it compresses the ipsilateral pyramidal tract, leading to spastic paralysis in the ipsilateral lower limb, and later affects the contralateral upper limb. C3–C4 lesions can cause diaphragmatic dysfunction. Additionally, there may be sensory disturbances and sphincter dysfunction below the level of the lesion.
Clinical Features of Tumors with Different Pathological Types
Neurofibroma, also known as neurilemmoma, is the most common type of intraspinal tumor. It frequently occurs in the extramedullary intradural space, often growing on spinal nerve roots and the spinal membrane, particularly the posterior spinal nerve roots. Most tumors develop on the lateral side of the spinal cord, and larger ones may cause 2–3 spinal nerve roots to adhere to the tumor. Neurofibromas generally have a complete capsule, a smooth surface, and a firm texture, with a clear boundary separating them from spinal cord tissue. The cut surface is uniform and semi-translucent milky white. Larger tumors may exhibit yellowish areas, small cysts, or hemorrhage. Occasionally, they form thick-walled cysts filled with watery fluid. Microscopically, they are typically classified into cystic and reticular types. The condition predominantly affects patients aged 20–40. Most patients exhibit classic symptoms and signs of intraspinal tumors: early-stage nerve root pain, followed by gradual spinal cord compression leading to spinal canal obstruction, resulting in sensory numbness and motor weakness, which may manifest as Brown-Séquard syndrome; advanced stages involve sphincter symptoms. The disease progresses slowly, though acute episodes may occur due to cystic degeneration of the tumor. Attention should be paid to cervical soft tissues and lateral cervical spine X-rays to detect dumbbell-shaped tumors. When symptoms cannot be explained by a single lesion, the possibility of multiple neurilemmomas should be considered. Some patients present with skin coffee-bean pigmented spots and multiple small nodular tumors, known as multiple neurofibromatosis (von Recklinghausen's disease). Cerebrospinal fluid protein levels are significantly elevated. Most tumors are easily resected with excellent outcomes. Tumors often adhere tightly to nerve roots, and sometimes nerve roots penetrate the tumor tissue, in which case the nerve root may be excised along with the tumor. In the cervical enlargement region, care should be taken to preserve normal nerves to avoid upper or lower limb dysfunction. Dumbbell-shaped and multiple tumors are difficult to remove completely, potentially leaving small remnants of the capsule or tumor tissue. Postoperative recovery is poorer in cases of acute cystic degeneration leading to flaccid paralysis.
Dumbbell-shaped intraspinal and extraspinal tumors refer to tumors located within the spinal canal and alongside the spine, connected through the intervertebral foramen. Most dumbbell-shaped neurofibromas are located outside the dura mater, originating from the spinal nerve roots, particularly the posterior roots. The tumors grow slowly and may extend from outside the dura mater along the nerve roots into the spinal canal or inside the dura mater, or from outside the spinal canal into the spinal canal. Anteroposterior X-rays may reveal abnormal soft tissue shadows near the spine, while oblique views may show enlargement of the intervertebral foramen and indentations on the pedicles, which can serve as diagnostic localization markers. If necessary, CT scans can clearly display the tumor's location and the compression of the dural sac. Li Shukui et al. reported three cases of cervical dumbbell-shaped tumors, all confirmed by CT to involve the transverse foramen, with the vertebral artery displaced due to compression. With adequate preoperative preparation, dumbbell-shaped neurofibromas can be completely resected in a single-stage surgery. The surgical approach and anesthesia choice vary depending on the tumor's location.
Malignant schwannomas in the cervical spinal canal are rare, with few reported cases domestically. Schwannomas originate from Schwann cells of peripheral nerve sheaths. Since bone tissue is also innervated and contains many Schwann cells, schwannomas can grow within bones. Benign cases are common, while malignant ones are rare, progress rapidly, and may lead to early paraplegia and urinary/fecal incontinence. CT and myelography aid in diagnosis.
Spinal meningiomas have the second-highest incidence after cervical neurofibromas. They typically grow in the spinal arachnoid membrane or pia mater, with a few arising from nerve roots. Cervical meningiomas account for 16.8% of all spinal meningiomas, less common than thoracic cases (80.9%) but more frequent than lumbar cases (2.3%). Most are located extramedullary, anterior or posterior to the spinal cord within the dura mater, with lateral positions being rare. The tumors have a complete capsule and clear boundaries with the spinal cord; their surfaces are smooth or nodular. Blood supply comes from the spinal meninges, so nearby meningeal vessels may thicken. These tumors grow slowly, resulting in a prolonged clinical course. Symptoms closely resemble those of neurofibromas, but distinguishing features include older patient age, less frequent radicular pain, and fluctuating symptoms. Surgery may involve significant bleeding, and sometimes resection of the affected dura mater is necessary for a cure.
Gliomas are the most common, with ependymomas being the predominant type, followed by astrocytomas; others like glioblastomas are rare. They usually grow infiltratively within the spinal cord, though a few have clear boundaries. The disease course varies by pathological type.
Lipomas are rare in the cervical region but more common in the thoracic spine, accounting for about 1% of cervical spinal canal tumors. They predominantly occur in young adults aged 20–30. Most are located beneath the pia mater, with rare cases outside the dura mater. Extradural lipomas have a complete capsule and little or no adhesion to the spinal cord, allowing surgical separation and resection. Subpial lipomas lack clear boundaries with surrounding tissues and may infiltrate neural tissue along blood vessels, resembling invasive tumors, making complete surgical separation difficult. The origin of spinal lipomas remains unclear; they may be part of congenital malformations or arise from ectopic tissue. Symptoms develop slowly, with radicular pain being uncommon, but sensory and motor deficits may occur below the lesion. During surgery, incising the pia mater to separate the tumor reveals yellow neural tissue underneath. Piecemeal resection is advisable to avoid damaging the spinal cord. Although complete removal is often unachievable, postoperative recovery is generally satisfactory.
Congenital tumors, also called embryonic remnant tumors, account for 5.9% of spinal canal tumors. They include epidermoid cysts, dermoid cysts, teratoid tumors, teratomas, chordomas, and others.
Hemangioma and vascular malformations. Lindau tumor is a relatively unique benign hemangioma in the central nervous system, also known as hemangio-reticuloma, hemangioreticuloma, or cerebellar hemangioma. It is less commonly found in the cervical spinal canal and generally occurs intracranially. It is more frequently seen in adults aged 35 to 40, with some patients having a family history. Clinically, it is difficult to differentiate from other common intraspinal tumors based on symptoms and myelography. Some cases may also be associated with polycystic sexually transmitted disease changes in the liver, pancreas, and kidneys, epididymal adenoma, renal clear cell carcinoma, pheochromocytoma, and hemangiomas in other locations.
The following should be noted when diagnosing and treating such patients:
1. For subarachnoid hemorrhage patients without obvious trauma, vascular malformations should be highly suspected.
2. If vascular malformation is suspected, angiography or myelography should be performed early to facilitate early diagnosis.
3. For patients with complete spinal canal obstruction, early cisternal puncture myelography should be performed. If possible, MRI should be conducted for a definitive diagnosis.
4. Simple vascular malformations rarely cause complete spinal canal obstruction. Therefore, for cases with complete obstruction, the possibility of concurrent tumors should be considered.
Surgical removal remains the primary treatment.
Cavernous angiomas (Cavernous Angiomas, Cavernoa), also known as cavernous malformations, can invade the spinal cord but are rare in the cervical spinal cord. They are typically found in the cauda equina and occasionally in the thoracic spinal cord. Spinal cavernous angiomas are usually confined to the vertebral body and may occasionally extend into the epidural space. Intradural cavernous angiomas are generally located within the spinal cord and are extremely rare in the extramedullary intradural space. They often present with hemorrhage or focal neurological deficits. Many cavernous malformations are asymptomatic and multifocal. Clinically, cavernous angiomas are slightly more common in women, primarily occurring between the ages of 20 and 40. The acute clinical manifestations of cavernous angiomas are almost certainly caused by hemorrhage, and rebleeding seems clinically inevitable. Statistics indicate an annual bleeding risk of approximately 1.6%. A series of studies suggest that cavernous angiomas often exhibit active, progressive enlargement, though the mechanism remains unclear. It is generally believed to result from capillary proliferation, vascular dilation, repeated hemorrhage with organization, and vascularization. Although partially embolized arteriovenous malformations may not be detected by angiography, angiography is still commonly used to exclude most arteriovenous malformations. MRI is an effective diagnostic tool, typically showing well-demarcated areas of low signal intensity on T1- and T2-weighted images. Some low signal intensities may be related to low blood flow within the malformation and the possible presence of ferromagnetic substances such as hemosiderin. These characteristic MRI findings may also be seen in intramedullary arteriovenous malformations, tumors, or injuries secondary to trauma or infection. With the advent of MRI, many angiographically occult cavernous malformations can now be easily detected, leading to an apparent increase in their incidence. Surgical resection is recommended for patients with progressive neurological injury.
Several rare symptoms of cervical spinal cord compression by tumors
Acute "apoplectic" transverse spinal cord syndrome: This is more common in cases of rapid progression of cervical spinal cord compression caused by spinal cord hemangiomas or intratumoral hemorrhage in extramedullary tumors. The mechanism may involve cervical spinal shock. Clinically, it manifests as loss of spinal cord function below the lesion for several hours to weeks. Reflexes are absent, with no pyramidal tract signs, presenting as flaccid paralysis, sphincter dysfunction, impaired sweating and thermoregulation, and vasomotor paralysis. If the lesion occurs above C4 , respiratory distress and circulatory disturbances are common and may lead to rapid death.
Cranial nerve damage caused by intraspinal tumors: Intraspinal tumors causing cranial nerve damage are almost always located in the cervical region. Multiple neurofibromatosis (Von Recklinghausen's disease) can lead to corresponding cerebellopontine angle cranial nerve damage due to the presence of neurofibromas in the cerebellopontine angle and spinal canal. The spinal trigeminal tract can descend to the C3 level, and high cervical intramedullary tumors may cause anterior headache or sensory disturbances, as well as loss of the corneal reflex. Extramedullary tumors at the foramen magnum can compress the spinal trigeminal tract and the last two cranial nerves in addition to the long tracts of the spinal cord, and may also result in a forced head posture. When intraspinal tumors cause increased intracranial pressure, cranial nerves may be compressed and paralyzed, leading to abducens and oculomotor nerve palsy.
Eye tremor Cervical spinal canal tumors often cause eye tremor, which is almost entirely horizontal tremor. The mechanism of its occurrence may be:
1. Cervical intramedullary tumors extending to the medulla oblongata or large occipital bone extramedullary tumors cause cerebellar dysfunction.
2. Involvement of the medial longitudinal fasciculus in the cervical spinal cord, which runs from the midbrain to the lower cervical segment, disrupts the connection between the vestibular apparatus and the eye, as well as motor neurons in the neck and neck muscles. Damage to this tract can also cause eye tremor.
3. Intraspinal cervical tumors lead to secondary circulatory disturbances and edema in the medulla oblongata.
4. Extramedullary tumors in the region of the large occipital bone foramen cause cerebellar dysfunction.
5. Occasionally, intraspinal cervical tumors are complicated by congenital eye tremor.
bubble_chart Auxiliary Examination
Lumbar Puncture and Cerebrospinal Fluid Examination The dynamic changes in cerebrospinal fluid (CSF) and increased protein content are important bases for the early diagnosis of intraspinal tumors. When an intraspinal tumor is suspected, Queckenstedt's test and CSF examination should be performed as soon as possible. Routine CSF examination in patients with intraspinal tumors may reveal increased protein content with normal cell counts, while dynamic examination (i.e., Queckenstedt's test) may show partial or complete obstruction.
X-ray Plain Film Examination Approximately 30–40% of patients exhibit bone changes. On conventional anteroposterior, lateral, and oblique views of the spine, common signs include: (1) enlargement or destruction of the intervertebral foramen; (2) spinal canal enlargement, manifested as widening of the interpedicular distance; (3) bone changes in the vertebral body and its appendages, such as vertebral bone defects or pedicle destruction; (4) intraspinal calcification, occasionally seen in a few spinal meningiomas, teratomas, and hemangioblastomas; (5) paravertebral soft tissue shadows. Since most intraspinal tumors are benign, early-stage X-rays often show no bone abnormalities. Sometimes, only indirect signs such as widened interpedicular distance, thinning of the spinal canal cortical bone, or spinal canal enlargement are visible in advanced stages. For dumbbell-shaped intraspinal tumors, enlargement of the intervertebral foramen may be observed. X-ray examination can exclude spinal cord compression caused by spinal deformities or tumors and remains an indispensable routine examination.
Myelography Currently, myelography is one of the effective methods for detecting space-occupying lesions in the spinal canal. Iodized oil (e.g., iophendylate) or water-soluble iodine contrast agents (e.g., Amipaque or Omnipaque) can be used for cervical spinal canal myelography, especially when injected via the cerebellomedullary cistern, which facilitates accurate diagnosis. The contrast agent may show a cup-shaped defect or obstruction at non-disc levels. Literature reports on 180 cases of schwannomas revealed myelographic findings in 150 cases: cup-shaped filling defects in 106 cases, horizontal cross-section in 18 cases, oblique cone-shaped in 7 cases, trumpet-shaped in 5 cases, and bead-shaped in 4 cases. Omnipaque, a second-generation non-ionic water-soluble iodine contrast agent, provides clear, safe, and reliable imaging. It can identify spinal cord tumors based on spinal cord enlargement, displacement, and subarachnoid space obstruction, combined with elevated CSF protein levels for accurate diagnosis. Due to adhesions or other factors, the obstruction level may not always represent the true tumor boundary. For example, Ni Bin et al. reported 137 cases of intraspinal tumors, with 4 cases showing a discrepancy of 1/4 to 1 vertebral body between the obstruction level and surgical findings. Unless a second myelography is performed, a single myelogram can only determine the upper or lower boundary of the tumor, and the obstruction morphology or bone involvement alone cannot confirm the tumor's nature. However, myelography can localize the lesion, followed by CT or MRI to obtain more information about the tumor.
CT Examination CT scanning offers sensitive density resolution and clearly displays spinal cord and nerve root structures in cross-sectional images. It can clearly reveal tumor soft tissue shadows, aiding in the diagnosis of intraspinal tumors—a capability lacking in traditional imaging methods. However, the scanning location, especially as the first imaging examination, must be determined based on clinical signs. Mispositioning may lead to missing the tumor site. CT can generally determine the segmental distribution and extent of intraspinal tumors but struggles to differentiate them from normal spinal cord parenchyma. CTM (CT with myelography) can display the relationship between the entire spinal cord and the tumor and differentiate intramedullary tumors from syringomyelia.
MRI Examination Magnetic resonance imaging is an ideal diagnostic method, free from the side effects of ionizing radiation. It allows three-dimensional observation of the spinal cord, clearly delineating the boundaries between tumor tissue and normal tissue, as well as the tumor's location, size, and extent. It directly outlines the tumor, revealing its longitudinal and transverse expansion and its relationship with surrounding tissues, making it the preferred method for diagnosing spinal cord tumors. MRI is particularly superior in distinguishing between intramedullary and extramedullary tumors. In MRI imaging of intramedullary tumors, the affected spinal cord appears enlarged, and the tumor exhibits varying signal intensities across different pulse sequences, aiding differentiation from syringomyelia. Extramedullary tumors can be accurately localized based on their relationship with the dura mater. Sagittal MRI imaging shows the tumor as a well-defined area with long T1 and T2 signals, predominantly long T1, with significant enhancement effects, sometimes appearing cystic. Axial images reveal the cervical spinal cord compressed to one side, with the tumor presenting as oval or crescent-shaped. For dumbbell-shaped tumors extending outward through the intervertebral foramen, the continuity of intra- and extradural masses can be observed. Since MRI directly provides sagittal imaging, it covers a larger spinal cord area than CT scans, a capability unmatched by CT. Moreover, MRI can display the tumor's size, position, and tissue density. The use of paramagnetic contrast agents like Gd-DTPA further enhances the clarity of tumor contours. Thus, MRI is crucial for both diagnosis and surgical localization, far surpassing CT or CT myelography (CTM) in these aspects.
Primary intraspinal tumors are not uncommon, but due to the variability in tumor nature and location, their clinical manifestations are complex and diverse, posing certain diagnostic challenges. Over the past decade, the emergence of new non-ionic iodine water-soluble contrast agents and the application of CT and MRI have made the localization of intraspinal tumors primarily reliant on auxiliary examinations such as myelography, CT scans, or MRI. Particularly, the accurate differentiation between intramedullary and extramedullary tumors depends heavily on imaging techniques. Ni Bin et al. reported 137 cases of intraspinal tumors without complete paraplegia, noting that the time from onset to definitive diagnosis has significantly shortened compared to the past, with advancements in imaging techniques playing a crucial role. However, no advanced equipment can replace conventional clinical examinations. A comprehensive understanding of medical history and neurological localization is of great guiding significance for differentiating spinal tumors from degenerative spinal diseases, as well as for determining the location of imaging examinations and interpreting image information. Only by mastering the characteristics of imaging examinations, selecting and applying them based on actual conditions, and closely integrating them with clinical practice, can the imaging diagnosis of spinal tumors become more accurate.
The diagnosis of intraspinal tumors should address the following issues:
Presence or absence of intraspinal tumors
Early diagnosis of intraspinal tumors is extremely important. Familiarity with their early clinical manifestations enables diagnosis and timely treatment before the spinal cord is severely compressed, thereby increasing the likelihood of better therapeutic outcomes. Generally, the basic clinical manifestations of intraspinal tumors are segmental neurological symptoms and spinal cord compression symptoms below the level of compression. Among the early symptoms, radicular pain is the most common, followed by motor disturbances such as muscle atrophy, weakness, and sensory disturbances. Changes in cerebrospinal fluid dynamics and elevated protein levels are important bases for the early diagnosis of intraspinal tumors. When an intraspinal tumor is suspected, Queckenstedt's test and cerebrospinal fluid examination should be performed as soon as possible.
The initial symptom of high cervical extramedullary compressive diseases is numbness in the fingertips, spreading from one finger to multiple fingers and progressing from distal to proximal. Additionally, neck pain accompanied by numbness in the distal upper limbs may occur, followed by limb weakness and a sensation of tightness in the chest or waist. Therefore, patients with neck, shoulder, back, or waist pain should undergo routine neurological examinations, with attention paid to gait. If changes in limb sensation, movement, or reflexes are observed, the possibility of an intraspinal tumor should be considered, and corresponding imaging examinations should be performed.
Whether the intraspinal tumor is intramedullary or extramedullary
1. Intramedullary tumors: Common clinical pathological types include gliomas (ependymomas, astrocytomas); radicular pain is less common; sensory changes are most pronounced at the level of the lesion and progress downward, showing segmental distribution with sensory dissociation; lower motor neuron symptoms such as muscle atrophy may occur; pyramidal tract signs appear late and are less pronounced, and spinal cord hemisection syndrome is rare or不明显; spinal canal obstruction occurs late or is不明显, cerebrospinal fluid protein elevation is不明显, and symptoms show little improvement after cerebrospinal fluid drainage; spinal process tenderness is rare, and spinal bone changes are less common.
2. Extramedullary tumors: Common clinical pathological types include neurofibromas and meningiomas; radicular pain is more common and has定位 diagnostic value; sensory changes are more pronounced in the distal lower limbs and progress upward, without sensory dissociation; pyramidal tract signs appear earlier and are more pronounced, lower motor neuron symptoms are不明显, and spinal cord hemisection syndrome is明显 more common; spinal canal obstruction occurs earlier or is明显, cerebrospinal fluid protein is明显 elevated, and symptoms worsen after cerebrospinal fluid drainage due to downward displacement of the extramedullary tumor; spinal process tenderness is more common, especially in extradural tumors, and spinal bone changes are more frequent.
Localization diagnosis of the cervical segment where the tumor is located
The level of spinal cord compression is primarily determined based on the following aspects:
1. Radicular pain or segmental sensory减退 in the area支配 by the spinal cord segment compressed by the tumor.
2. The level of sensory disturbance is not difficult to diagnose in the stage of complete spinal cord compression, but it is already too late. Many authors have pointed out that radicular pain is not only a common initial symptom but also of significant importance for early localization diagnosis. Compression and destruction of nerve roots result in localized segmental sensory loss. When the spinothalamic tract is compressed, due to its layered arrangement within the spinal cord, the early sensory loss level in cases of extramedullary tumors does not truly indicate the segment where the tumor is located. If radicular pain and spinothalamic tract symptoms coexist, and their levels are inconsistent, radicular pain has a more definitive localizing value.
3. The muscles innervated by the tumor-compressed area exhibit flaccid paralysis. In the motor system, tumor compression and irritation of the anterior horn of the spinal cord or the anterior roots of the spinal nerves lead to lower motor neuron paralysis, which is more pronounced in the cervical enlargement region and holds significant localizing value.
4. Loss of reflexes associated with the segment where the tumor is located. Due to compression of the spinal cord and spinal nerve roots at the tumor's level, the reflex arc is disrupted, resulting in weakened or absent reflexes. However, below this level, hyperreflexia, weakened or absent superficial reflexes, or pathological reflexes may occur.
5. Changes in autonomic nervous function. Below the tumor level, there may be an absence of sweating or reduced sweating, though this is less reliable for localization compared to sensory levels. Additionally, it holds little significance for cervical spinal cord tumors.
bubble_chart Treatment Measures
Patients with mild symptoms or spontaneous remission can be treated conservatively, with repeated and multiple physical examinations and MRI follow-ups (Note: there is a risk of recurrence and spinal traumatic hemorrhage). However, the only effective treatment is surgical resection of the tumor. Since primary intraspinal tumors are mostly benign, about 3/4 of cases can be cured by surgical resection. Therefore, surgical resection should be actively pursued for intraspinal tumors. Even if complete resection is not possible, partial or bulk resection should be performed to alleviate or reduce the tumor's compression and damage to the spinal cord. Once the diagnosis is confirmed, conditions for surgery should be actively prepared, and surgical treatment should be promptly performed regardless of the severity of spinal cord compression. Surgery carries risks, and symptoms may recur. Surgical risks vary depending on the functional location of the tumor, with fewer postoperative deficits for exophytic tumors. Appropriate treatment methods should be selected. Intraoperative spinal cord evoked potential monitoring helps reduce lack of vitality-related complications.
Surgical Methods
Position: The patient is placed in a prone or lateral position during surgery.
Anesthesia: To prevent neck hyperextension or torsion from exacerbating cervical spinal cord injury and respiratory impairment, and to facilitate exposure of the surgical site, awake lowering qi endotracheal tube general anesthesia is used. After anesthesia, the head is fixed on a specialized head frame.
Surgical Approach: The surgical approach is usually posterior or through the thinnest part of the tumor to the spinal cord surface. Recent studies have confirmed that resection of the posterior vertebral structures significantly reduces the compressive strength and stability of the spine and carries the risk of worsening nerve injury. Therefore, after posterior structure resection, fusion, internal fixation, and bone grafting should be used to restore spinal stability. Wang Chenyang et al. used unilateral fenestration to treat intraspinal tumors, aiming to maximally preserve the stability of the posterior vertebral structures, with satisfactory results.
Surgical Procedure
1. Microsurgical Technique: Generally, for extramedullary cervical spinal tumors, the use of a head frame allows for optimal positioning, advanced lighting equipment, and the application of bipolar coagulation, reducing surgical difficulties. However, for high cervical extramedullary tumors, due to thick neck muscles and deep lesion locations, unclear exposure and rough manipulation may injure the cervical spinal cord and important blood vessels, leading to severe complications such as respiratory arrest. Surgery carries a certain mortality rate, or due to inadequate hemostasis, postoperative hematoma may compress the cervical spinal cord, resulting in limb paralysis or even respiratory failure and death. Under a microscope, fine structures invisible to the naked eye can be clearly seen, such as the arachnoid membrane and tumor, nerve roots and tumor, and the boundary between the tumor and cervical spinal cord, especially small blood vessels supplying or draining the tumor. The application of microsurgical techniques can prevent and reduce these complications. Based on cervical spinal MRI, the incision site and size are determined. A small sharp-nosed rongeur is used to remove the outer cortical bone of the lamina, and a micro-drill is used to thin the cancellous bone, making the lamina sheet-like, which is then removed piece by piece. It is contraindicated to insert one side of the rongeur between the lamina and dura mater and remove the lamina piecemeal, as this may unknowingly injure the spinal cord. After laminectomy, the dura mater is incised under the microscope, and the arachnoid membrane is opened along the long axis of the tumor to release cerebrospinal fluid for better tumor exposure. The cervical spinal cord is protected with cotton pads to prevent accidental injury from suction and instruments. The tumor is carefully dissected, and if 1-2 nerve roots connected to the tumor cannot be preserved, they may be cut. Several small blood vessels penetrating the tumor are coagulated and then cut, which helps reduce bleeding and maintain surgical clarity. Coagulation should be performed away from the cervical spinal cord.
When resecting a dumbbell-shaped schwannoma, the intradural extramedullary portion of the tumor should be removed first. Since schwannomas usually have no adhesion to the spinal cord, they can be easily resected, creating space that facilitates the removal of the extradural and foraminal portions of the tumor. During resection of the foraminal portion of the tumor, a small {|###|}stirred pulse{|###|} is often visible on the cephalad side of the tumor. This should be coagulated and divided first, followed by piecemeal intracapsular resection, and finally removal of the tumor capsule. Avoid forceful traction on the foraminal tumor capsule to prevent tearing the vertebral {|###|}stirred pulse{|###|}. If exposure is inadequate, the anterior wall of the foramen can be drilled open to achieve complete initial stage [first stage] resection. In cases of foraminal bleeding where hemostasis is difficult, avoid blindly inserting bipolar forceps into the foramen for coagulation to prevent injury to the vertebral {|###|}stirred pulse{|###|}. If bleeding occurs, muscle fragments with gelatin sponge can be used for compression hemostasis.
2. Laminotomy: Traditionally used for lumbar disc nucleus pulposus removal, some have applied it to the excision of intraspinal tumors in the cervical region, aiming to minimize damage to the posterior vertebral structures and maintain postoperative spinal stability. Wang Chenyang et al. employed unilateral laminotomy to treat 15 cases of intraspinal tumors, striving to maximally preserve the stability of the posterior vertebral structures, with satisfactory results. During the surgery, the patient is placed in a prone or lateral position. Unilateral laminotomy confines the bone window to one side of the lamina, preserving the spinous process, supraspinous ligament, and interspinous ligament medially, and the facet joints laterally. The upper and lower laminae removed do not exceed half, and the window is created from the interlaminar space, not exceeding half a lamina in either direction. The window length can reach 15mm–20mm, and the width 10mm–15mm. The tumor is excised piecemeal or en bloc. If the tumor spans more than one segment, an additional window can be opened to remove it. Due to the relatively small surgical field, to avoid pulling or compressing the spinal cord, the tumor should be excised in situ as much as possible. From a cross-sectional view of the vertebra, the annular bone structure of the spinal canal is largely preserved, and from a longitudinal view of the posterior vertebral structures, only part of the lamina and ligamentum flavum are removed. This maximizes the integrity of the posterior vertebral structures, ensuring postoperative spinal stability.
Common intraspinal tumors include schwannomas and meningiomas, most of which are small and can be removed through a single window. To avoid injuring the spinal cord, it is advisable to excise the tumor piecemeal in situ.
Advantages of laminotomy for intraspinal tumor removal: (1) Minimal trauma to the vertebral bone structure, with little impact on postoperative spinal stability; (2) Minimal impact on the spinal cord, dura mater, nerve root canal, and spinal canal contents, largely avoiding the possibility of iatrogenic spinal stenosis caused by postoperative scar tissue proliferation and adhesion; (3) The surgical field is small, requiring precise preoperative localization and higher surgical skill; (4) Suitable for the removal of extramedullary spinal tumors, but its applicability to intramedullary tumors remains to be further explored.
Selection of surgical approaches for tumors in different locations:
1. Extradural tumors: These tumors are often malignant and frequently invade surrounding bone, making complete resection difficult and radical cure unlikely. Piecemeal or subtotal resection can be performed for decompression. For tumors involving the vertebral body, the surgical approach is preferably anterior or anterolateral, with resection of the affected vertebra and replacement of the defect using an artificial vertebral body or autologous bone graft. Although posterior laminectomy can achieve decompression, it exacerbates spinal instability, necessitating supplementary internal fixation devices such as Harrington rods, Luque rods, pedicle screws, and plates to stabilize the spine. These tumors progress rapidly, and once significant spinal cord or nerve damage occurs, surgical outcomes are poor.
2. Intradural extramedullary tumors: These tumors are mostly benign, such as neurofibromas and meningiomas, typically located ventrally or dorsolaterally to the spinal cord, with intact membranes and small sizes, resulting in high rates of complete resection and favorable outcomes.
The surgery is generally performed via a posterior approach. After laminectomy, the dura mater is opened, and the tumor is excised. Hemostasis is crucial during surgery, and care must be taken to handle the spinal cord gently and cautiously, with the option to cut 1–2 dentate ligaments if necessary. If a nerve root is directly connected to the tumor, it may be severed as appropriate, but adjacent nerve roots should not be injured. For dumbbell-shaped tumors, a paraspinal incision can be made simultaneously. For larger tumors, intracapsular piecemeal resection can be performed first to reduce the tumor size before complete removal.
3. Intramedullary tumors: These can be divided into two categories: (1) Soft, infiltrative tumors such as malignant astrocytomas and glioblastomas, which grow invasively with indistinct boundaries from normal spinal cord tissue, making resection impossible; (2) Firm, well-demarcated tumors, which may be completely resectable.
Because the surgery requires opening the spinal cord, there is a high probability of injuring the spinal cord, aggravating spinal cord edema. Postoperative complications are numerous, and the surgical risk is high, requiring the use of microsurgical techniques.
4. Cervical intraspinal and extraspinal dumbbell-shaped tumors: Most intraspinal and extraspinal dumbbell-shaped neurofibromas are located outside the dura mater, originating from the spinal nerve roots, particularly the posterior roots. The tumors grow slowly and may extend from outside the dura mater along the nerve roots to the extraspinal space or into the dura mater, or from the extraspinal space into the spinal canal. With adequate preoperative preparation, intraspinal and extraspinal dumbbell-shaped neurofibromas can be completely resected in a single-stage surgery. The surgical approach and choice of anesthesia vary depending on the tumor's location. The anterolateral aspect of the cervical intervertebral foramen is the transverse foramen, through which the vertebral artery passes. Li Shukui et al. reported three cases of cervical intraspinal and extraspinal dumbbell-shaped tumors confirmed by CT to involve the transverse foramen, with the vertebral artery displaced by compression. If the intraspinal tumor is addressed first, although the spinal cord can be visualized directly, there is a risk of injuring the vertebral artery when transecting the tumor isthmus through the intervertebral foramen. Once the vertebral artery is ruptured, uncontrollable bleeding may occur. Therefore, the patient is first placed in a supine position, and the paravertebral tumor is exposed under local anesthesia. The vertebral artery is isolated and protected or ligated if necessary, and the tumor isthmus is transected at the intervertebral foramen, with all visible tumor tissue removed. The patient is then repositioned to a lateral decubitus position on the unaffected side, and the intraspinal tumor is resected via a posterior approach with hemilaminectomy or total laminectomy under local anesthesia. Since the muscles innervated by the cervical spinal nerves are each supplied by a single nerve, severing a cervical nerve would inevitably impair hand function. Therefore, the approach involves intracapsular tumor curettage followed by removal of the membrane, aiming to preserve as much residual nerve fiber as possible to minimize functional impairment of the hand.
If intraspinal tumors are detected early and treated with early surgery, most patients achieve good clinical outcomes. However, some patients with large intraspinal tumors or tumors located in the upper cervical spine may die from respiratory failure after surgery or experience recurrence some time post-operation. As for the recovery of spinal cord nerve function, it is related to the degree and duration of spinal cord compression in the patient.
The clinical manifestations of intraspinal tumors are diverse, and if not carefully considered, misdiagnosis often occurs, leading to confirmation only after varying degrees of paralysis have developed. The clinical presentation of cervical intraspinal tumors is very similar to cervical spondylosis, and due to the high prevalence of degenerative spinal diseases, spinal cord tumors are frequently overlooked. This not only subjects patients to prolonged ineffective treatment but also increases the risk of irreversible damage to the spinal cord nerves. Therefore, clinicians should pay high attention to this issue. Ni Bin et al. reported 137 cases of intraspinal tumors, among which 21 cases of early cervical intraspinal tumors were misdiagnosed as cervical spondylosis, with 2 cases mistakenly undergoing cervical decompression surgery. The primary reason for misdiagnosis is insufficient understanding and low vigilance regarding intraspinal tumors. Neglecting patient history and basic examinations is also a significant contributing factor.
Cervical intraspinal tumors primarily need to be differentiated from the following conditions:
Cervical spondylosis: Intraspinal tumors must be distinguished from myelopathic cervical spondylosis. Clinically, differentiation is mainly based on age characteristics, clinical manifestations, and X-ray or CT scans. Cervical spondylosis results from degenerative changes in the cervical spine, where the intervertebral discs lose elasticity and protrude into the spinal canal, or due to posterior vertebral osteophytes, facet joint hyperplasia, ligamentum flavum hypertrophy or calcification, or even vertebral lamina thickening, leading to spinal cord compression and a series of neurological impairment symptoms and signs. Clinically, any middle-aged or older individual with limb or trunk numbness, weakness, or upper motor neuron damage signs, whose symptoms fluctuate and progressively worsen in a wave-like manner, should be suspected of having cervical spondylosis. However, the clearest and most definitive differentiation method is MRI examination, and the most reliable differential diagnosis is based on a comprehensive analysis combining MRI findings with clinical manifestations.
Early-stage high cervical extramedullary schwannomas and neurofibromas are difficult to distinguish from cervical spondylosis. Shan Hongkuan et al. reported 7 cases of high cervical extramedullary tumors, all initially diagnosed as cervical spondylosis and treated with various methods, resulting in some symptomatic relief. Among these, 4 cases showed degenerative changes on cervical X-rays, making them easily confused with cervical spondylosis. The reason may be that schwannomas grow slowly, and the cervical spinal canal is relatively spacious, providing some reserve space. The tumors are often connected to 1–2 nerve roots, initially causing nerve root irritation symptoms. Only when the disease progresses further does it involve the spinal cord, leading to incomplete limb paralysis, a girdle-like sensation in the chest or waist, or sphincter dysfunction and respiratory impairment. Sometimes, nerve root irritation symptoms fluctuate in a wave-like manner without progressive spinal cord compression.
Key points for differentiating cervical intraspinal tumors from cervical spondylosis:
1. Cervical oblique X-rays showing enlarged intervertebral foramina or thinning of the vertebral lamina can support the diagnosis of extramedullary schwannoma;
2. Cervical myelography, especially contrast injection via the cerebellomedullary cistern, can easily confirm the diagnosis;
3. MRI of the cervical spine: Sagittal views often reveal well-defined tumors with long T1 and T2-weighted signals and significant enhancement effects. These tumors often exhibit central mixed long T1 and T2-weighted signals, while axial views show eccentric or crescent-shaped tumor shadows displacing the spinal cord to one side. On T1-weighted images, the tumor signal is weaker than the spinal cord; on T2-weighted images, the tumor signal is slightly stronger than the spinal cord signal;
4. Cerebrospinal fluid protein levels in intraspinal tumor patients often exceed 2g/L.
Spinal arachnoiditis: This is rare in the cervical spine and often has a history of infection or trauma. Symptoms are fluctuating, diverse, and irregular, with myelography showing typical patchy distribution.
Spinal subcutaneous nodules: These can be easily distinguished based on history, clinical presentation, and imaging findings.
Syringomyelia develops slowly. It commonly occurs in the lower cervical and upper thoracic segments of adults aged 20–30. There is sensory dissociation in one or both sides across multiple segments, along with lower motor neuron paralysis, but no spinal canal obstruction. MRI can confirm the diagnosis and differentiate it from intramedullary tumors.
