Intradural Spinal Tumors

What are intradural spinal tumors and how are they classified?

“Intradural” describes the location: inside the dura mater. “Intramedullary” or “extramedullary” describes the tumor’s relationship to the spinal cord.

Intradural tumors fall into two main categories:

• Intradural extramedullary: located outside the spinal cord but within the dura. Symptoms typically arise from compression of the cord and/or nerve roots.
• Intradural intramedullary: arising within the spinal cord itself. These are often slow-growing but require specialized microsurgical technique.

Important: because many tumors grow slowly, the body can “adapt” for a period of time. Symptoms often develop gradually and may be mistakenly attributed to “degenerative spine disease.”

How common are they—and who is at risk?

Primary spinal tumors are relatively uncommon, but clinically significant because of the risk of spinal cord compression.

Intradural tumors represent a subset of primary CNS tumors, and more than half are extramedullary. Risk can be higher in certain genetic syndromes, such as:

• Neurofibromatosis (especially NF2) — associated with multiple schwannomas/meningiomas.
• Von Hippel–Lindau disease — associated with hemangioblastomas in selected cases.

The age profile depends on tumor type. For example, meningiomas are more common after age 50 and are seen more often in women, while many intramedullary tumors have different distributions.

What are the most common tumor types?

The most frequent diagnosis depends on whether the tumor is extramedullary or intramedullary.

Intradural extramedullary

• Meningioma: arises from arachnoid cap cells; most commonly in the thoracic spine and more frequent in women.
• Schwannoma (nerve sheath tumor): well-circumscribed tumors from Schwann cells; may occur at any level.
• Less commonly: neurofibroma, hemangioma, hemangioblastoma, and others.

A proportion of nerve sheath tumors can have a dumbbell configuration (extension through the neural foramen). Malignant transformation is rare but has been reported in selected cases.

Intradural intramedullary

• Ependymoma: often well circumscribed; arises from ependymal cells of the central canal and may be associated with syringomyelia or cysts.
• Astrocytoma: often low-grade, frequently less sharply demarcated, and may also be associated with syringomyelia/cysts.
• Less commonly: hemangioblastoma (sometimes with VHL), high-grade gliomas, and others.

What symptoms do they cause—when should I worry?

Onset is often subtle. “Night pain” and progressive neurological decline are classic warning signs.

Common symptoms (both intramedullary and extramedullary):

• Pain in the neck/back, often persistent and sometimes worse at night.
• Numbness / tingling (sensory changes).
• Weakness in the arms and/or legs.
• Gait difficulty, imbalance, coordination problems.
• Spasticity and/or increased tendon reflexes.
• In advanced cases: bladder/bowel dysfunction.

Because many patients also have degenerative spine findings (disc herniation, stenosis, spondylolisthesis), a detailed neurological examination is essential to distinguish incidental imaging changes from true neurological symptoms.

How is diagnosis made (MRI and additional evaluation)?

MRI is the test of choice. It defines location, relationship to the cord/roots, and contrast-enhancement patterns.

Typically, evaluation includes:

• Contrast-enhanced MRI of the relevant spinal segment.
• In selected situations: MRI of the entire neuraxis (e.g., congenital dysraphism or genetic syndromes).
• Assessment for cysts/syringomyelia and for features of hemorrhage in intramedullary tumors.

In meningiomas, findings may include a dural tail (dural enhancement) and/or calcifications. Definitive diagnosis, however, requires histopathology (biopsy or resection specimen).

Key differences: extramedullary vs intramedullary tumors

Extramedullary tumors typically compress the spinal cord from the outside, while intramedullary tumors expand or infiltrate the cord from within. This influences surgical strategy and prognosis.

• Extramedullary: often have a clear plane relative to the cord. The goal is usually complete removal, with high cure rates for benign lesions.
• Intramedullary: arise within cord parenchyma. Some (e.g., ependymomas) often have well-defined surgical planes and can be removed completely, while others (e.g., astrocytomas) may have ill-defined margins. In those cases, the priority is maximal safe resection with preservation of function.

When is observation appropriate, and when is surgery recommended?

There is no one-size-fits-all answer. Decisions depend on symptoms, tumor size, growth rate, and the degree of pressure on neural structures.

Close observation may be reasonable when:

• the tumor is small and asymptomatic,
• there is no clear compression of neural structures,
• surgical risk outweighs potential benefit (rare cases, typically with major comorbidities).

Surgery is recommended when:

• there are neurological deficits (weakness, gait disturbance, sphincter dysfunction),
• pain is persistent or progressive,
• MRI demonstrates significant compression of the cord or roots,
• there is tumor growth on serial imaging.

Note: for selected intramedullary lesions, early intervention—before fixed neurological injury develops— may improve functional outcome.

How is surgery performed—and what does “microsurgery” mean?

Intradural surgery demands fine dissection around the spinal cord and nerve roots. The goal is maximal tumor removal with minimization of neurological risk.

In broad terms, surgery may include:

• Posterior approach with tailored laminectomy/laminotomy at the appropriate levels.
• Dural opening followed by microscopic tumor removal.
• For benign extramedullary tumors: the usual goal is gross-total resection.
• For intramedullary tumors: a myelotomy (often through the dorsal midline) is performed followed by microsurgical resection.

“Microsurgery” means the use of a high-definition operating microscope, micro-instruments, meticulous tissue-handling, and often adjuncts such as intraoperative ultrasound or an ultrasonic aspirator for internal debulking of larger lesions.

What is intraoperative neuromonitoring and why is it critical?

Continuous, real-time monitoring of spinal cord function during surgery—while the patient is under anesthesia— to reduce the risk of permanent injury.

In practice, we commonly use a combination of:

• SSEPs (somatosensory evoked potentials) — assess sensory pathways.
• TcMEPs (transcranial motor evoked potentials) — assess motor pathways.
• In selected cases: EMG, direct root/nerve stimulation, and targeted sphincter monitoring.

If significant monitoring changes occur, the team responds immediately with established protocols—optimizing blood pressure, adjusting maneuvers, and, when appropriate, limiting or stopping resection—with the primary goal of protecting neurological function.

Risks/complications—and how we reduce them

Any operation within the spinal canal carries inherent risks. Modern neurosurgical practice reduces risk through precise localization, microsurgical technique, and continuous intraoperative neuromonitoring.

Potential risks include:

• Neurological worsening (temporary or, rarely, permanent)—particularly with intramedullary tumors.
• CSF leak or pseudomeningocele.
• Infection, hematoma, wound-healing problems.
• Spinal instability after extensive bone removal (uncommon; depends on technique and levels).

How we reduce risk:

• Meticulous preoperative planning with high-quality MRI.
• Neuromonitoring (SSEPs/TcMEPs) for intradural tumors.
• Careful hemostasis before dural opening, watertight closure, and sealing materials when indicated.
• Strict microsurgical technique with high-definition digital microscopy.
• “Safety first” strategy for tumors with ill-defined margins: subtotal resection prioritized to preserve function, when appropriate.

What to expect after surgery (recovery, rehab, follow-up)

Recovery depends on tumor level, tumor type, and neurological status before surgery. Our goal is safe mobilization and a gradual return to daily activities.

Postoperative care commonly includes:

• Early mobilization when safe, guided by physiotherapy.
• Pain control and management of spasticity as needed.
• Individualized rehabilitation (gait training, strengthening, balance).
• Histopathology results (definitive diagnosis) often determine the follow-up strategy.
• Follow-up MRI within a defined timeframe, depending on lesion type and extent of resection.

Many neurological symptoms improve gradually over weeks to months—especially when surgery occurs before severe, fixed neurological injury develops.