Primary Bony Spinal Lesions

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Chapter 106 Primary Bony Spinal Lesions

Patrick W. Hitchon, Timothy Lindley, Michael Ebersold

General Discussion

Primary tumors of the spine are extraordinarily uncommon. The incidence of primary spinal neoplasms has been estimated to be between 2.5 and 8.5 per 100,000 per year,¹ the equivalent of an estimated 7500 new cases per year in the United States.² Overall, primary spinal tumors are more common in men than women. Osteoid osteoma, osteoblastoma, osteochondroma, plasmacytoma, chordoma, and chondrosarcoma all occur more commonly in men at a nearly 2:1 ratio compared with women.² In a review of 6221 bone tumors at the Mayo Clinic, Dahlin and Coventry³ found that less than 10% of all primary tumors involved the spine. In a recent, even more extensive review at the Mayo Clinic, Unni et al. (unpublished data, personal communication, 2000) reviewed 8091 skeletal bone tumors in patients who underwent surgery. Of these 8091 skeletal tumors distributed throughout the skeleton, 2334 were benign and 5757 were malignant. A further analysis of this group revealed that 510 tumors involving the spine were malignant and only 145 were benign. A more detailed grouping of the benign tumors is presented in Table 106-1. Not all patients with benign or malignant tumors undergo surgery. Therefore, these figures likely underestimate the true incidence of the disease.

Table 106-1 Skeletal Distribution of Benign Tumors

	Number of patients with
Tumor Type	Tumors Involving the Spine	Benign Skeletal Tumors
Giant cell tumor	32	574
Osteoid osteoma	30	332
Osteoblastoma	29	87
Hemangioma	28	109
Osteochondroma	19	748
Chondroma	5	290
Chondroblastoma	1	119
Chondromyxoid fibroma	1	45
Neurilemmoma	0	14
Fibrous histiocytoma	0	9
Lipoma	0	7
Total	145	2334

Only those patients undergoing surgery and who, therefore, have tissue available for pathologic review are included in this table.

From Unni KK et al: Unpublished data, personal communication, 2000.

The presenting symptoms of night pain, pain at rest, or progressive neurologic deficit should prompt the clinician to entertain the diagnosis of benign or malignant disease of the spine. The primary complaint of most patients with primary tumors of the spine is pain. In a recent review, more than 84% of the patients complained of pain, either localized to the back (60.2%) or radicular (24%). There was no apparent difference between the pain symptoms in patients with benign disease involving the spine and those with malignant disease involving the spine.⁴ Fifty-five percent of the patients with malignant spine tumors and 35% of the patients with benign tumors demonstrated objective evidence of neurologic deficits. It is postulated that with the advent and increased availability of MRI, the number of patients presenting with neurologic deficits will decrease secondary to earlier diagnosis.

Although a rapidly progressive neurologic deficit is more suggestive of a malignant tumor or a pathologic fracture, it is not uncommon for patients with benign tumors involving the spine to experience rather rapid progressive neurologic deterioration. Nevertheless, because of the slow growth of these benign tumors of the spine, there is often a prolonged interval between the onset of symptoms and the diagnosis.

The data presented in Table 106-1, contrasted with those in Table 106-2, demonstrate the relative frequency or infrequency of these primary tumors involving the spine. In spinal tumors the distinction between tumors considered benign or malignant can be somewhat misleading. Chordoma is listed among the malignant tumors involving the spine, although tumor growth in some patients with chordoma is extremely slow. Conversely, giant-cell tumor is considered a benign tumor, although this particular lesion, in some cases, can be aggressive in nature. Early recurrence following surgery for giant-cell tumors is common, and there is even the potential for metastasis. Furthermore, progression to a high-grade sarcoma can occur in up to 10% of patients following postoperative radiation therapy.⁵

Table 106-2 Skeletal Distribution of Malignant Tumors

	Number of patients with
Tumor Type	Tumors Involving the Spine	Malignant Skeletal Tumors
Myeloma	232	803
Lymphoma	82	694
Chondrosarcoma	54	892
Chordoma	51	356
Osteosarcoma	37	1649
Ewing tumor	16	514
Hemangioendothelioma	13	80
Fibrosarcoma	9	255
Secondary chondrosarcoma	7	121
Mesenchymal chondrosarcoma	4	25
Malignant giant-cell tumor	2	35
Malignant fibrous histiocytoma	2	83
Dedifferentiated chondrosarcoma	1	120
Hemangiopericytoma	1	13
Periosteal osteosarcoma	0	69
Adamantinoma	0	36
Desmoid fibroma	0	12
Total	511	5757

Only those patients undergoing surgery and who, therefore, have tissue available for pathologic review are included in this table.

From Unni KK et al: Unpublished data, personal communication, 2000.

Often, plain radiographs demonstrate the site of the lesion and, in many cases, can be diagnostic. CT and MRI are often extremely valuable for defining the extent and precise location of the lesion. The need for myelography to diagnose and define benign tumors of the spine has been nearly eliminated by these two imaging advances. However, angiography can often be of significant benefit in confirming the nature of the lesion. In addition, angiography may be used for accurate definition of the vascular extent of the lesion and for preoperative embolization, when appropriate. Often, preoperative embolization can decrease the operative blood loss and therefore the postoperative morbidity. Aneurysmal bone cysts, giant-cell tumors, and hemangiomas, in particular, should be considered for preoperative embolization.

Some of the primary tumors of the spine have very characteristic imaging findings. The clinician should be aware of the classical radiographic findings associated with these tumors, because this knowledge is not only helpful for identifying the cause of the symptoms, but may also be of value by limiting additional testing and in guiding management decisions. Several of the common spinal lesions have unique features and are presented later in this chapter.

Management

Staging

Once a primary spinal tumor is suspected, thorough imaging of the lesion is required, including plain radiographs, CT, and MRI to narrow the differential diagnosis. In addition, a complete systemic workup should also be performed. A CT of the chest, abdomen, and pelvis, or a positron emission tomography scan can help to identify any additional distant pathology. Ultimately, however, a tissue diagnosis is typically required to aid in preoperative planning. The decision to perform a biopsy must be a part of a comprehensive management strategy to reduce the risk of local recurrence. It has been suggested that resecting the tissue along the biopsy tract during the definitive resection could prevent recurrence caused by the contamination of surrounding tissues during the biopsy.⁶

After a histopathologic diagnosis is made, staging can be completed to aid in presurgical planning. The Enneking classification system assists in determining the goals of surgery and is a guide to adjuvent therapy. Both benign and malignant tumors can be staged and are classified as either high- or low-grade, depending on the local extent of disease and the presence of metastasis. Management strategies range from no surgical intervention to palliative surgery based on the stage.⁷ The Weinstein, Boriani, Biagini (WBB) classification⁸ was developed to guide a surgeon in determining the most appropriate surgical approach. In the WBB system, the vertebra is divided into 12 radiating zones (numbered 1 through 12, clockwise starting dorsally at the spinous process) and into five layers (A–E, from paravertebral to dural involvement). In addition, the longitudinal extent of the tumor is noted. Depending on the area of involvement, a surgical approach is recommended. For tumors involving only the vertebral body (zones 4–9), an anterior approach is recommended, whereas a dorsal approach is ideal for tumors involving the pedicles, facets, spinous process, and lamina (zones 3–10).

Surgery

The goal of surgical management of spine tumors is to establish a definitive diagnosis, decompress the neural elements, maintain or achieve spinal stability, and if possible, cure the patient. In the case of benign tumors involving the spinal axis, cure can often be achieved if proper consideration is given to size, extent, and location of the tumor.

Not every patient with a primary tumor of the spine is a candidate for surgery. For example, hemangioma is often an incidental finding, and surgery is not appropriate unless specific clinical symptoms or signs are present. In general, progressive neurologic loss is a rather definite indication that surgery should at least be considered in the patient with a benign lesion. The patient’s age, his or her general well-being, and the expected morbidity from the surgical procedure are all factors that must be considered.

Spine tumor resection can be en bloc or intralesional.¹ En bloc resection, or spondylectomy, is the resection of the entire tumor in one piece. En bloc resections are further subdivided into marginal or wide. Marginal resection dissects through the pseudocapsule of the tumor, and wide resection provides a cuff of normal tissue (>2 mm of healthy bone, reactive periosteum, or pleura) with a margin of healthy surrounding tissue. For primary tumors, the long-term local tumor control, survival, and cure are dependent on en bloc tumor resection. For this reason, there has been resurgent interest in treating primary spinal tumors with en bloc resection. Intralesional resection is the incision into the tumor, and debulking from within. Although intralesional resection of spine tumors results in good neurologic outcomes, local recurrence rates remain high. Wide resection occurs when the excision is inclusive of the pseudocapsule. As applied to the spine, marginal en bloc resection or intralesional resection with an adjuvant (e.g., phenol, liquid nitrogen, methyl methacrylate) may be curative for aneurysmal bone cysts, giant-cell tumors, osteoid osteomas, and osteoblastomas. Evidence is mounting that wide en bloc resections for primary tumors such as chondrosarcoma, chordoma, osteogenic sarcoma, and Ewing sarcoma may effect a longer disease-free interval and a potential cure.

However, en bloc resections often require extensive procedures associated with high rates of morbidity and mortality.⁹ Bandiera et al.⁹ recently published the largest study to date examining the complication rates in en bloc resections of spinal tumors. They reviewed 134 consecutive attempted en bloc resections from 1990 to 2007 at a single institution. Major complications occurred in 43 cases, including three deaths. Major complications were also more common in patients who had undergone a previous failed resection at a prior institution. Of those previously treated, 72% suffered a major complication, whereas 20% with a new presentation suffered a major complication. Furthermore, with an average follow-up period of 37 months, the local recurrence rate was higher in patients treated previously elsewhere (40% vs. 16%). Thus, surgical management of primary spinal tumors is associated with high morbidity and recurrence rates, both of which can be reduced if treatment from biopsy to resection occurs at the same institution by a dedicated multidisciplinary team.

When the biopsy is performed prior to the definitive procedure, if possible, the biopsy path should be well marked and the soft tissue along the biopsy path should be resected along with the tumor at the time of surgery. Also, one must always be cautious to avoid contamination of surrounding tissues with tumor cells. In addition, resecting the dura as a margin may increase the risk of intradural seeding.¹⁰ When a fusion is planned, bone graft should be obtained through a separate surgical setup.⁵

Radiation

Primary tumors may benefit from neoadjuvant or postoperative adjuvant radiation or chemotherapy. In general, the more benign tumors (e.g., osteoid osteoma, osteoblastoma, osteochondroma) have a poor response rate to these therapeutic modalities, and gross resection of the tumor will effect a cure. A significant concern in patients receiving radian therapy for the more benign tumors is the development of postradiation sarcomas. In a review of 59 patients who underwent operation for spinal sarcoma at Memorial Sloan-Kettering Cancer Center, 7 patients had postradiation sarcomas at a median interval of 14 years from the time of radiation.^11,¹² Other tumors, such as osteogenic sarcoma and Ewing sarcoma, may benefit from neoadjuvant chemotherapy followed by resection. Chondrosarcoma and chordoma are extremely radiation therapy resistant and still chemotherapy resistant, but positive surgical margins are irradiated.

A great challenge in radiation therapy to the spine is that the dose the spinal cord can tolerate is significantly lower than the dose required to achieve local tumor control. Experience with extremity sarcomas has demonstrated good local control with 60 Gy for postoperative radiation therapy in patients with close surgical margins. For patients with gross residual disease after resection, 70 Gy is typically delivered in 200-cGy fractions. The spinal cord is thought to tolerate no more than 50 Gy when delivered in 200-cGy fractions.¹¹ Several strategies have evolved in an attempt to deliver tumoricidal doses of radiation while avoiding radiation-induced myelopathy. These advances include intraoperative radiation therapy, brachytherapy, proton beam therapy, high-dose conformal photon therapy, and stereotactic radiation. Each of these techniques provides a higher tumoral dose of radiation with reduced damage to surrounding tissues and potentially smaller fields than do conventional external beam techniques.

Intraoperative radiation therapy (IORT) involves the delivery of a custom-designed electron beam or high-dose brachytherapy that precisely demarcates the tumor volume. Lead shields and gold foil are used to shield the spinal cord.¹³ Unfortunately, this technique is somewhat labor intensive, and dosimetry considerations are difficult to predict around the spinal cord. An alternative radiation approach is brachytherapy, or the direct application of radioisotopes within the resection cavity. Earlier attempts with the use of iodine-125 were disappointing due to difficulties with dosing near the spinal cord. However, intraoperative therapy with yttrium-90 has recently been approved by the U.S. Food and Drug Administration and has been demonstrated to be effective in the treatment of sarcoma. Yttrium-90 is a pure β-emitter with limited penetrance. DeLaney et al.¹⁴ treated five patients with yttrium-90 plaques placed intraoperatively, including two chondrosarcomas and one osteosarcoma. With a median follow-up of 24 months, no local recurrences were observed in the chondrosarcoma or osteosarcoma patients and no treatment-related myelopathy or neuropathy was detected.¹⁴

Proton beam therapy ^15,¹⁶ has an inherent geometric advantage over therapy with photons and electrons because of the finite range of penetration in tissues (Bragg-peak effect). Proton beams can be designed so that a uniform dose is administered to the target volume (i.e., tumor) and a minimal dose is delivered to the critical surrounding tissues (e.g., spinal cord, bowel, esophagus). Proton beam treatment plans are often supplemented with additional photon beam therapy to improve tumoral coverage. Studies have shown outstanding results for the control of chordoma and chondrosarcoma with proton beam therapy. Hug¹⁷ reported on 33 patients with skull base chordomas and 25 patients with skull base chondrosarcomas treated to a mean dose of 70.7 cobalt gray equivalents (CGEs) with a mean follow-up period of 33 months. Local control was achieved in 76% of the chordoma patients and 82% of the chondrosarcoma patients.¹⁷ A major drawback for proton beam therapy is the limited availability of treatment centers in the United States to accommodate the demands for treating primary tumors, particularly chordomas and chondrosarcomas. Currently, proton beam centers are located at the Loma Linda University Medical Center, Massachusetts General Hospital, Indiana University, University of Florida, M.D. Anderson Cancer Center in Houston, and INTEGRIS Cancer Campus in Oklahoma.

High-dose conformal photon therapy (3D-CRT) has made it possible to deliver cytotoxic doses to tumor volume, doses similar to proton beam radiation, without the side effect of radiation-induced myelopathy.¹⁸^–²² Similar to proton beam therapy, 3D-CRT is a method of irradiating a tumor volume with an array of photon beams that are individually shaped to conform to a 3D rendering of the target. Treatment planning considers dose inhomogeneities caused by the differing electron densities of various tissues and calculates the resulting dose distribution using sophisticated algorithms. Intensity-modulated radiation therapy (IMRT) represents an advanced form of 3D-CRT in which multileaf collimators are used to dynamically change the field shape during treatment, thus permitting the delivery of an inhomogeneous dose that conforms more tightly to the target region. Because of the precise dosimetry demands of IMRT, accurate delivery requires reproducible patient setup and positioning. Recent data suggest that IMRT may improve the clinical outcome of inoperable tumors and those tumors requiring a boost after surgical resection. Yamada et al.²³ reported on 14 patients with primary spinal malignancies and 21 with metastatic lesions treated with IMRT at Memorial Sloan-Kettering Cancer Center. Patients had unresectable disease near the spinal cord and either previously received radiation therapy or were prescribed doses beyond spinal cord tolerance. With a mean follow-up period of 11 months, local control was achieved in 81% of primary malignancies and 75% of metastatic lesions. No radiation-induced myelopathy was observed, and more than 90% reported palliation from pain, weakness, or paresthesia.²³

Chemotherapy

Chemotherapy has not been found to be beneficial in the majority of spinal tumors. However, recent evidence has shown promise in the treatment of osteogenic sarcoma. A recent prospective randomized trial demonstrated 3-year event-free survival rates of 71% and 78% for patients with osteogenic sarcoma treated with either cisplatin, doxorubicin, and methotrexate versus muramyl tetrapeptide following resection, respectively.²⁴ Chordoma, also previously thought to be chemoresistant, has also been shown to be sensitive to a new class of tyrosine kinase inhibitors. Imatinib mesylate (Gleevac) is one such tyrosine kynase inhibitor that has shown promise in early clinical trials. In initial studies, imaging revealed extensive tumor necrosis in six out of six patients treated with imatinib mesylate.² Sunitinib (Sutent) is another tyrosine kinase inhibitor recently developed that is currently being tested on chordoma patients in clinical trials.¹¹ As new therapeutic strategies continue to be developed, chemotherapy holds great promise for the treatment of primary spinal tumors in the future.

Hemangioma

Hemangioma is one of the common benign lesions involving the spinal axis. It is often discovered incidentally during evaluation of patients with back or neck pain. The relatively low incidence, noted in Table 106-1, confirms that most patients with hemangioma are not treated surgically. Several studies have demonstrated that this entity may affect as much as 10% to 12% of the population.²⁵^–³³ Less than 5% of patients with hemangiomas develop symptoms.³⁴ Spine surgeons become involved with the treatment of hemangioma when the lesion causes spinal cord or nerve root compression. In general, decompressive surgery should be reserved for this specific group, because such surgery is usually not required for the management of pain that is not associated with neurologic involvement. In a 1993 review of spinal hemangioma from the Mayo Clinic, it was demonstrated that, in fact, it is rare for incidental hemangiomas associated with pain alone to progress to spinal cord compression.²⁸ Only 2 of 59 patients with previously diagnosed asymptomatic or painful lesions later developed spinal cord compression. Symptomatic hemangiomas are usually observed during adulthood and found to occur in the thoracic region.²⁹ Patients with asymptomatic lesions do not require further evaluation unless pain or neurologic deficits develop. Patients with painful lesions should be followed closely, with a combination of radiographic studies and periodic neurologic evaluations.

In the past, subtotal tumor removal with postoperative irradiation was often considered the treatment of choice in symptomatic tumors. The development of modern spine surgery techniques and the advancements made possible by a skilled surgical team and modern instrumentation have now made total removal of these lesions a viable option in many cases. Preoperative embolization has also significantly decreased intraoperative and postoperative morbidity.

Imaging

Plain radiography, tomography, and CT often clearly demonstrate the typical coarsened trabeculae within the involved vertebrae, with a characteristic honeycombed appearance. Gadolinium enhancement and MRI evidence of a soft tissue component are often observed (Fig. 106-1).

FIGURE 106-1 A, CT of vertebral body demonstrating the typical trabeculated appearance of a hemangioma of the lumbar spine. B, T1-weighted sagittal MRI of the thoracic spine demonstrates an indeterminate mass, later pathologically proven to be a hemangioma involving the body and right pedicle of T2. This hemangioma displaced the thecal sac and produced mild to moderate deformity of the adjacent thoracic spinal cord. In asymptomatic patients, this appearance is often an incidental finding.

Histology

Most of the trabeculae are atrophic because of the abnormal blood vessels, although some become thickened and sclerotic. Microscopically, there are two main types of trabeculae. These are characterized by cavernous or capillary vessels. In some cases, adipose tissue may be found within the lesion.²⁷ Spinal cord compression may arise from the expansile nature of the vertebral body, an associated soft tissue component of the tumor that rests within the spinal canal, a compression fracture of the weakened vertebral body, or, rarely, an epidural hemorrhage.

Management

The management scheme should depend on the size, extent, and location of the lesion; the patient’s general age and health; and the patient’s clinical course and neurologic findings. Surgical decompression is recommended if there is progressive neurologic decline. It is important for the spine surgeon to be familiar with the variety of available surgical approaches so that the most appropriate technique can be used to remove the tumor. Many patients for whom laminectomy and postoperative radiation therapy would have been recommended can now be treated using a lateral or ventral surgical approach to the lesion. Laminectomy followed by radiation therapy of lesions involving the vertebral body yielded a 93% rate of neurologic recovery, without recurrent symptoms, in a 52-month follow-up period.³¹ Laminectomy without radiation therapy for subtotal tumor resections resulted in tumor control rates of 70% to 80%.²⁹^–³¹ It appears that postoperative irradiation reduces the risk of tumor recurrence in patients after subtotal tumor removal. Nevertheless, because of the potential morbidity and relative lack of efficacy associated with radiation therapy, total lesion removal often should be attempted.

Vertebroplasty and kyphoplasty have also been advocated for the treatment of symptomatic hemangiomas. Studies have recently reported excellent pain relief with no evidence of posttreatment instability and preservation of vertebral body height. Such a less invasive approach may be ideal for patients who are not good surgical candidates.³⁵

Eosinophilic Granuloma (Langerhans Cell Histiocytosis)

Eosinophilic granulomas are vertebral lesions found in 10% to 15% of cases of Langerhans cell histiocytosis. Most commonly, eosinophilic granulomas are identified in children younger than age 10, and spinal lesions have been reported in 6.5% to 25% of cases involving bone.³⁶ Eosinophilic granulomas involving the adult lumbar spine are very rare, and to date only 13 cases have been reported.³⁷ These self-limiting, benign lesions cause bony destruction³⁸ secondary to the local proliferation of histiocytes. Occasionally, multiple levels are involved and can rarely result in pain, but are more often identified incidentally.⁵

Radiographically, eosinophilic granulomas are identified as destructive bony lesions with well-demarcated borders and no evidence of a soft tissue mass. The adjacent disc spaces are well preserved (Fig. 106-2). These findings differentiate eosinophilic granulomas from other lesions in the differential diagnosis (e.g., infection, benign tumor, or malignancy).⁵

FIGURE 106-2 A 27-year-old man presents with a 2-month history of midback pain, leg weakness, and difficulty with urination. Examination showed him to be paraparetic ⅗ bilaterally with hyperactive reflexes. Axial (A) and sagittal (B) CT scans show a lytic process involving the T7 body and left pedicle and, to a lesser extent T6. Sclerosis suggests an indolent process such as eosinophilic granuloma. C, MRI shows a soft tissue mass with destruction of the bone, extending into the canal and compressing the cord. There is extension of the soft tissue mass into the left paraspinal space. D and E, A left-sided transthoracic T6 partial and T7 total corpectomy was performed with humeral allograft, and screw and rod fixation. When seen 15 months later, the patient continued to have back pain and some unsteadiness, although he had no leg weakness or sphincter complaints.

Management

Prior to any invasive treatment, a biopsy is indicated. In many cases, symptoms will resolve over time, and a conservative approach should always be considered first. The vertebral body height can be restored spontaneously if the areas of endochondral ossification were preserved and the child is young. Therefore, treatment is generally conservative with activity limitations and bracing.^36,³⁸ A recent report described the use of percutaneous vertebroplasty to treat eosinophilic granuloma involving the cervical spine of a child, though this approach was taken only after conservative measures failed and a more aggressive approach was declined by the family.³⁹ In cases where vertebral body collapse results in loss of neurologic function, decompression and biopsy are warranted.⁵ If the bony destruction leads to instability that persists despite a course of conservative management, arthrodesis is required.³⁸

Aneurysmal Bone Cysts

Aneurysmal bone cysts (ABCs) are benign, proliferative non-neoplastic lesions that may occur in any part of the skeleton. Although this is not a tumor per se, its classical appearance and presentation should be familiar to clinicians dealing with spine lesions. ABCs make up 1% to 6% of primary spinal neoplasms, with approximately 40% to 45% involving the lumbar spine, 30% involving the thoracic spine, and 25% to 30% involving the cervical spine.⁴⁰ Lesions are often not confined to a single vertebra; instead they bridge two or more levels in approximately 40% of cases.^41,⁴² Although primary ABCs are of unknown cause, a secondary form of ABC has been described that arises within eosinophilic granulomas, simple bone cysts, osteosarcomas, chondroblastomas, or giant-cell tumors.⁴²

ABCs of the spine typically present in young patients in their second decade, with a slight predominance in women.⁴³ In one series, 60% of lesions arose in the neural arch and 40% arose in the body. Pain that occurs especially at night and that is localized to the site of the mass is the most common presenting complaint.⁴⁴ The presence or absence of a neurologic deficit depends on the site of the tumor and on the degree of compression of adjacent neural elements. Symptoms and signs may vary from cord compression with myelopathic findings to radicular features of single-root involvement. The clinical course is commonly progressive over several months because of the slow growth of these lesions, although rapid growth can also occur. Imaging the anatomic delineation of ABCs is often best achieved with plain radiography and CT, which accurately define the degree of bone destruction and full extent of the lesion (Figs. 106-3A and B). MRI can be helpful for defining a spinal cord compressive component, and it readily demonstrates the full epidural extent of the mass. The rather classical appearance of the involved vertebra is that of a multiloculated, expansile, highly vascular mass with eggshell-like cortical bone and blood product fluid levels. Collapse of involved bodies and involvement of adjacent ribs may also be observed.

FIGURE 106-3 Aneurysmal bone cyst (ABC). A, Plain radiograph of lumbar spine demonstrating the typical appearance of a lytic, eccentric, expansile lesion of the vertebral body and dorsal elements of L5, as observed with an ABC. B, CT of lumbar spine demonstrating the lytic lesion of the dorsal elements and the vertebral body, with the tumor having an osseous shell consisting of a thin rim of cortical bone surrounding the mass. C, Plain and subtracted angiographic views display the typical segmental vascular supply of an ABC with vascular staining.

Selective spinal angiography has both diagnostic and, potentially, therapeutic value.⁴⁴ In addition to defining the relationship of the arterial supply of the lesion to the arterial supply of the cord, angiography also defines the involvement of the vertebral arteries with cervical lesions. The anatomic location of the artery of Adamkiewicz in lower thoracic or upper lumbar lesions can be defined clearly with spinal angiography. Finally, preoperative embolization is a useful adjunct that may decrease the intraoperative blood loss (Fig. 106-3C).