eMedicine Specialties > Neurosurgery > Neoplasm

Intramedullary Spinal Cord Tumors: Treatment

Author: Alfred T Ogden, MD, Assistant Professor, Department of Neurological Surgery, Columbia University Medical Center
Coauthor(s): Nicholas Wetjen, MD, Pediatric Neurosurgery Fellow, University of Utah, Primary Children's Hospital; Thomas L Francavilla, MD, Chief of Neurosurgery Section, Department of Surgery, Brookwood Medical Center
Contributor Information and Disclosures

Updated: Apr 9, 2009

Treatment

Medical Therapy

Because most of these tumors are slow growing and locally contained, surgical extirpation, where possible, is the treatment of choice. In selected situations, watchful waiting can be considered. Steroids are used in the perioperative period or if a rapid decline in neurologic function occurs, but steroids are not considered tumoricidal.

Radiation therapy

The slow-growing nature of these neoplasms makes proving the benefit of this treatment difficult. Conclusions regarding the efficacy of radiation therapy as a primary therapy are not available for all tumor types. Series have shown poor control of local disease in ependymomas.

Data are available that suggest surgically excised ependymomas need not undergo subsequent radiation therapy. Evidence of this modality preventing recurrence or halting progression of low-grade astrocytomas is lacking. No lesion should undergo radiotherapy without a tissue diagnosis. This modality may be primary treatment for (1) inoperable tumors and (2) aggressive lesions such as anaplastic astrocytomas and glioblastomas.

Radiotherapy may be useful for (1) residual tumor after surgery and (2) recurrent tumor, but controversy exists. A dose of 50 Gy is delivered to the tumor in daily fractions of 1.5-2 Gy. This dose has not been shown to be curative in most studies. Some series report local failure rates reduce when more than 50 Gy is administered.

Pitfalls include (1) acute and delayed myelopathy, (2) diminished skeletal growth in young children, and (3) increased difficulty with subsequent surgical tumor removal. This is particularly important if radiotherapy does not control the growth of the lesion.

Chemotherapy

Intraoperative Details

Surgical positioning

The patient is positioned prone on bolsters or a Wilson frame, freeing the abdomen and thorax from pressure and taking care to pad all pressure points. For cervical and high thoracic lesions, the head is immobilized using a Mayfield head holder or equivalent.

Neurophysiologic monitoring

Intraoperative neurophysiologic monitoring is used by many surgeons to obtain feedback on the effects of positioning and manipulation of neural structures during surgery.²

Anesthesia

General anesthesia is performed using total intravenous anesthesia (TIVA), which entails a combination of intravenous opioids and a continuous administration of propofol. Halogenated volatile anesthetics are avoided because these interfere with sensory evoked potentials (SSEP). Low levels of muscle relaxants are used to minimize spontaneous muscle activity but permit motor evoked potentials and detect elicited EMG activity. The spinal cord is sensitive to decreased perfusion, and an arterial line is needed to ensure that dips in blood pressure are detected and corrected as quickly as possible.

Approach

A standard dorsal midline approach is used. A midline incision and subperiosteal dissection of the paraspinal musculature exposes the lamina and spinous processes. The level is confirmed by radiograph. A laminectomy or laminoplasty is performed exposing the dorsal dura. Meticulous hemostasis is obtained. The tumor may be visualized with ultrasound to confirm adequate exposure prior to opening the dura. A durotomy is made in the midline, and the dural edges are tacked to the soft tissues laterally, exposing the arachnoid overlying the swollen spinal cord.

Myelotomy

Using an operating microscope, the arachnoid is opened and tacked laterally to the dural edges. In most cases the myelotomy is performed in the midline between the dorsal columns. The normal surface anatomy may be distorted by the tumor and the midline may need to be approximated by visualizing a vertical line running equidistant from both dorsal root entry zones. The line is cauterized, and the pia is sharply incised. Traversing blood vessels are cauterized and divided. The dorsal columns are dissected apart. Occasionally, eccentric lesions may be approached through the dorsal root entry zone.

Tumor excision

If the tumor has an exophytic component, this is the initial area of approach. Otherwise, the tumor is encountered after the dorsal columns are split. Then, gradually, if a clear plane between cord and tumor is identifiable, the spinal cord parenchyma is dissected circumferentially off of the tumor capsule. Pial tacking sutures are useful to maintain exposure. Many tiny bridging vessels need to be cauterized and cut during this process.

Early on in the dissection, a specimen should be sent for frozen section. Eventually, the tumor poles are identified and the tumor is freed of all but its ventral attachments, then, gradually, the ventral portion of the tumor is liberated and disconnected from its major blood supply off of the anterior spinal artery. Although these tumors should optimally be removed en bloc (see Image 6), this is sometimes impossible in cases of very large tumors, tumors with poor internal integrity, and tumors with an unclear surgical plane. An ultrasonic aspirator is often useful either to debulk internally to facilitate capsule dissection or to perform an inside out resection when no clear plane is identifiable.

Dural closure

After tumor resection and hemostasis, the dorsal columns are gently rotated back into position. A primary dural closure is achieved using a running stitch. In cases of subtotal resection, a dural patch may be used to expand the thecal sac. Various dural substitutes and sealants are available to aid closure. A Valsalva confirms a water-tight closure.

Soft tissues

Meticulous hemostasis is achieved. The muscles are loosely approximated with an absorbable stitch, such as a 0 Biosyn. A water-tight fascial closure is achieved with an interrupted absorbable stitch such as a 0 Vicryl. The subcutaneous tissues are closed with interrupted inverted 2.0 Vicryl. The skin is approximated with a running 3.0 Nylon.

Postoperative Details

A typical regimen of postoperative care for patients after surgery for intramedullary tumors entails the following:

• A level body position for 24-48 hours
• A 3-7 day steroid taper
• Foley catheter until out of bed
• Sequential compression device and subcutaneous heparin for deep venous thrombosis (DVT) prophylaxis until ambulatory
• Incentive spirometry until ambulatory
• Careful wound monitoring for cerebrospinal fluid (CSF) leak
• Physical therapy, occupational therapy and rehab (Virtually all patients will have some degree of sensory dysfunction that is a result of dorsal column manipulation during surgery. Most patients benefit from a course of inpatient rehab.)

Follow-up

Patients are followed clinically and radiographically. The vast majority of patients will have some degree of new proprioceptive dysfunction that requires intensive physical therapy. Most patients will benefit from a course of in-patient rehabilitation. Some clinicians obtain immediate postoperative imaging, others delay imaging for a period of months after surgery. Routine interval imaging is required for years, even after gross radiographic resection. If neurological function worsens, immediate re-imaging is of course warranted. Residual tumor can be considered for repeat resection, radiation therapy, or observation. If tumor recurrence is noted, imaging the entire neuraxis is warranted to rule out distant seeding through CSF spaces.

Complications

The majority of patients have an increased sensory deficit after surgery. This may be due to edema from surgical manipulation or an alteration in blood flow. Most deficits greatly improve within 3-6 months, and patients develop compensating mechanisms with therapy. Complications are as follows:

• Progressive or delayed neurologic deficit
• Hematoma
• CSF leak requiring wound revision, spinal drainage, and or reoperation 
• Wound infection
• Sepsis
• Infectious meningitis
• Chemical meningitis, particularly from epidermoid and dermoid tumors
• Deep venous thrombosis
• Pulmonary embolism
• Spinal instability
• Arachnoiditis
• Perforated gastric ulcer

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