Medical Causes of Neck Pain

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CHAPTER 47 Medical Causes of Neck Pain

Paul Cooke, Alvin Antony, Ramnik Singh

INTRODUCTION

Neck pain is a frequent complaint to doctors in Western societies.¹ Valkenburg et al.² demonstrated in a large epidemiological study in the Netherlands that the lifetime prevalence of neck pain was 30% in males and 43% in females. By definition, neck pain is pain perceived in a region bounded superiorly by the superior nuchal line, laterally by the lateral margins of the neck, and inferiorly by an imaginary transverse line through the T1 spinous process.³ Pain in the neck may arise from any of the structures in the neck, which include the ligaments, osseous structures, intervertebral discs, muscles, zygapophyseal joints, dura, and nerve roots.

For the purposes of this chapter, the discussion of the potential causes of neck pain will be limited to nonmechanical or medical causes of neck pain. Other chapters within this text will further elaborate on mechanical etiologies of neck pain. Potential medical causes of neck pain include tumor, infection, inflammatory and inflammatory-like conditions (e.g. spondyloarthropathies, rheumatoid arthritis, fibromyalgia), metabolic disorders (e.g. Paget’s disease), and cardiovascular disease (e.g. myocardial infarctions, carotid dissection).

TUMORS

The initial clinical presentation of a patient with tumor involvement of the cervical spine varies considerably. Evaluating and diagnosing cervical tumors early is clinically challenging because the initial symptom of neck pain is a common complaint. Most patients tend to be observed for some time before full evaluation or radiographic investigation is done. For this reason, clinicians must pay special attention to certain ‘red flags’ that may suggest a non-benign origin of the symptoms. Clinical presentation may range from mild pain, stiffness, or palpable mass to significant neurologic compromise. Night pain, weight loss, and anorexia are classic hallmarks of neoplasm. A history of malignancy should raise the suspicion of possible recurrence or a new primary tumor.

Evaluating the patient with suspected neoplasm begins with a complete history and physical examination. Appropriate diagnostic imaging studies should begin with plain radiographs and consideration of cervical computed tomographic (CT) scan, magnetic resonance imaging (MRI), and bone scan, when indicated.

Primary cervical spine bone tumors are rare, accounting for only 0.4% of all tumors ⁴ and for only 4.2% of the primary bone tumors that occur in the spine above the sacrum.⁵ Cervical spine primary bone tumors occur disproportionately less frequently than those in the thoracic and lumbar spine. Dreghorn et al.⁶ found that five of 55 primary spinal bone tumors were cervical. Boriani and colleagues⁵ noted 63 cervical tumors out of 366 primary bone tumors of the spine. In another series, Weinstein and McLain⁷ reported only six of 82 primary spinal bone tumors involved the cervical spine.

Primary benign tumors of the cervical spine

Primary benign bone tumors of the cervical spine occur most commonly in the first 20 years of life, with the incidence of malignant tumors increasing significantly with age. In a series of 41 benign tumors of the cervical spine (patient ages 4–50 years old) treated at the Istituto Ortopedico Rizzoli between 1952 and 1988, Levine and colleagues ⁸ noted that 32 patients were younger than 20 years old. Another study, by Bohlman et al.,⁹ noted that nine out of nine patients under 21 years old had benign cervical tumors, but 10 of 12 patients over 23 years old had a primary malignant tumor. Neurologic findings may be common on initial presentation. The most common initial symptom is neck pain that is often worse at night, with continued pain at rest that is not typically relieved with analgesics.⁹ The duration of symptoms may be prolonged, averaging 19 months in some series.¹⁰

Benign primary bone tumors are generally distributed to all levels of the cervical spine. The most common vertebral levels are C2, C4, and C7; C1 is the least frequent site.¹¹ Radicular symptoms can be a common complaint but neurologic abnormalities may be absent. In a series by Levin et al.¹⁰ of 41 patients, most of the benign tumors were located in the posterior elements. Osteoid osteomas and osteoblastomas were found in the pedicles and facet joints. Giant cell tumors, eosinophilic granulomas, and aneurysmal bone cysts were most common in the vertebral body, although aneurysmal bone cysts commonly occur in the posterior elements as well.¹⁰

Hemangiomas

Hemangiomas are the most common benign spinal tumor and occur in about 10% of the population. While they are usually asymptomatic, pathological fractures or expansion of the bony architecture into neural structures may create symptoms.¹² These tumors demonstrate a slight female predominance. Hemangiomas of the cervical spine are much less common than in the thoracic and lumbar spines. In a review of literature, Nguyen and colleagues found 10 of 148 reported cases of hemangiomas were located in the cervical spine. Radiographically, hemangiomas have a striated or honeycomb texture, which is the expression of hamartomatous growth of the vascular tissue within the vertebral body. The posterior spinal elements are rarely involved.¹⁰

Aneurysmal bone cyst

Aneurysmal bone cysts typically occur in the first two decades of life without male or female predilection.¹³ Isolated disease commonly occurs in the posterior arch, but patients may have circumferential involvement.¹⁴ Aneurysmal bone cyst is a pseudotumoral, hyperplastic, and hemorrhagic lesion whose pathogenesis is unknown. These cysts frequently occur in the spine, most commonly in the thoracic or lumbar spine.¹⁵ Twenty-five percent of aneurysmal bone cysts of the spine observed at the Rizzoli Institute presented in the cervical spine.¹⁶

Fibrous dysplasia

Fibrous dysplasia is a hamartomatous condition rarely occurring in the vertebrae. When it does occur, it is usually asymptomatic and generally found incidentally. It can, however, cause weakening of trabecular structures and vertebral collapse, thus causing neck pain, muscle spasm, and associated torticollis. Typical radiographs may show an expanded vertebral outline with faded radiolucency of the vertebral body. No treatment is necessary for latent lesions, but stability is indicated when mechanical failure occurs or is impending.¹⁷ Radiotherapy should be avoided in active lesions as it is ineffective and can induce sarcoma. Rarely, bone grafting and curettage may be advised.¹⁸

Osteoid osteoma

The most common benign primary tumor in the cervical spine is osteoid osteoma, which is frequently found in the posterior arch.⁸ The male to female ratio of occurrence is 2:1 with most cases presenting before the age of 25. One-tenth of all osteoid osteomas occur in the spine and 30% of those in the cervical region. One should consider this diagnosis among adolescents or young adults complaining of persistent neck pain frequently associated with nondermatomal radiation to the upper limb. The pain often interferes with sleep, sometimes causing muscle spasm or torticollis. Patients may respond favorably to aspirin. On imaging, this tumor appears as a small radiolucent area which is more commonly identified by the zone of reactive sclerosis around it. Bone scans are often helpful to focus the examinations on standard radiographs and localize the CT/MRI scan to the suspected lesion. Although there have been some cases of spontaneous regression, curettage of the nidus is usually necessary. In addition, one potential developing technology is percutaneous radiofrequency denervation, which has shown effectiveness in nonspinal lesions and may be useful for the cervical spine.

Osteoblastoma

Osteoblastomas are similar to osteoid osteomas but are larger (>2 cm) and less common. Forty percent of reported osteoblastoma cases were found in the spine ¹⁹ with 25% of those occurring in the cervical region. There is a male predominance and they generally occur before the age of 25. They most commonly arise from the posterior elements, sometimes invading the vertebral body. Symptoms range from nocturnal pain to severe neck pain with muscle spasm.²⁰ Plain radiographs can usually identify osteoblastomas. Patterns vary from that of a giant osteoid osteoma, a rounded radiolucent mass larger than 2 cm with variable amount of scanty ossifications, to that of a highly aggressive purely lytic lesion, which is distinguished from low-grade osteosarcoma.¹⁹ The ‘active’ lesions are positive on bone scan and present on CT scan with well-marginated sclerotic borders and a thin reactive shell that thickens the cortical outline.²¹ These lesions can be treated with curettage with low recurrence rates (5–10%). More aggressive lesions can also be treated with curettage but have higher recurrence rates (20%). If feasible, selective arterial embolization is mandatory to reduce bleeding before curettage and may serve as a treatment option or adjuvant. Cryotherapy or postoperative radiotherapy may also be indicated.

Giant cell tumors

Giant cell tumors are ironically considered ‘benign’ by some despite the fact that they have a high recurrence rate and sometimes metastasize into the pulmonary region. Their prevalence in the spine is low (2–10%). Giant cell tumors are more common in females, with a peak incidence in the third decade. On plain radiographs, they often manifest as purely lytic lesions. Staging utilizes a combination of plain films, bone scan, CT scan, MRI, and biopsy. Surgical treatment depends on the staging of the tumor and the degree of involvement of critical vascular and neural structures. Stage 2 lesions may be treated with curettage plus adjuvant therapy (phenol, liquid nitrogen, or methylmethacrylate), whereas stage 3 lesions may require marginal en bloc resection. If the tumor demonstrates malignant transformation, then radiation therapy may be initiated. Preoperative embolization should be considered to reduce blood loss and morbidity. Giant cell tumors have a high recurrence rate and re-resection is often not an option. Therefore, repeated embolization may be necessary to control or perhaps even cure a very large lesion.²² In addition, cryosurgery,²³ bisphophonates,²⁴ and interferon and radiotherapy may hold some potential for control of the lesion.

Osteochondroma

Osteochondromas are the second most common tumor of the bone but occur infrequently in the spine (1–3% of all osteochondromas). They are often asymptomatic but may become painful if an exostosis grows into the spinal canal or if it develops a large subcutaneous protuberance. In most cases, a palpable painless mass arising from the anterior or anterolateral surface of the vertebral body is found by the patient during skeletal maturation. The tumor forms dense conglomerate masses containing radiolucent areas with clusters of calcifications; typically, the cortex of the host is evaginated, with the cancellous bone continuing directly into the vertebral cancellous bone.²⁵

Primary malignant tumors of the cervical spine

Due to their rarity as well as proximity to vital structures, diagnosis and treatment of primary malignant tumors of the cervical spine can be challenging. Accurate diagnosis is often delayed due to their slow evolution and non-specific symptoms. They are frequently discovered only after imaging has been ordered to evaluate intractable pain, or neurologic or anatomical abnormalities. Some of the higher-grade malignancies (osteosarcoma, malignant fibrous histiocytoma) that have a more rapidly evolving clinical picture may be found earlier but again are difficult to treat given their anatomic locations adjacent to other critical structures. Definitive treatment decisions are individualized, and there is no clear evidence-based algorithmic approach.

The clinical onset is usually non-specific. Patients will often present with cervical pain mostly occurring at night accompanied by muscular spasm. Larger lesions extending anteriorly from C2 might cause dysphagia. Pathologic fracture may occur from neoplastic destruction and erosion. Finally, major neurologic deficits from cord compression or the development of incomplete quadriplegia can also occur.

While plain radiographs remain the first imaging study, MRI of the cervical spine is essential in making a definitive diagnosis and should be performed after negative plain radiographs are obtained if the following symptoms persist: dysphagia, persistent night pain, sudden occurrence of neurologic symptoms, and extremity pain which may or may not fit a dermatomal distribution. CT scan and bone scan may also be helpful. Vertebral body tissue biopsy is also important to differentiate between primary and secondary malignancies and to determine individual treatment options.

Oncologic staging is based on the histology and local aggressiveness of the tumor and is a key determinant of treatment. Depending on the stage, type of tumor, and resectability, treatment options for malignant tumors may involve surgery, chemotherapy, and/or radiation.

Chondrosarcoma

Chondrosarcoma is a malignant bone tumor whose cells tend to differentiate into cartilage. Its prevalence in the spine is greater than 6%²⁶ but shows no specific prevalence in the cervical, thoracic, or lumbar segments. Patients may present with a slow-growing mass or neurological symptoms if the tumor compresses nearby neural or vascular structures. Plain radiographs may show an extraosseous mass found arising from the posterior elements of the involved vertebra. This may appear irregularly ossified, lobulated, or cauliflower-like, with irregular limits extending out toward the soft tissues. On CT scan, a cartilaginous cap may be appreciated. Treatment is surgical excision, as radiation and chemotherapy are not effective.

Chordoma

Chordomas are malignant tumors that transform from ectopic notochordal remnants and are typically seen in the spheno-occipital region (including the first cervical vertebra) and sacrum. They are slow-growing tumors which generally manifest clinically after the fifth decade of life. Fewer than 5% occur before age 20. Chordomas of the cervical spine occur almost exclusively in the vertebral body. The most common complaint is a long history of mild neck pain together with symptoms related to an anterior slow-growing mass: dysphagia, upper respiratory obstruction, and Claude-Bernard-Horner syndrome, or slow cord and nerve root compression from expansile chordomas within the spinal canal.^9,²² In rare cases, a palpable mass may be appreciated. Cranial nerve compression can be provoked by craniocervical chordomas.²⁸ On plain radiographs, chordomas generally appear completely radiolucent, although calcifications may occasionally be present within the tumor mass.²⁹ Treatment options include surgery and radiation therapy. Metastases are rare and late; however, local progression of the disease is the most frequent cause of death.

Malignant fibrous histiocytoma

Malignant fibrous histiocytoma is a sarcoma of histiocytic origin that consists generally of histiocytes and fibroblasts and is quite rare in the cervical spine.¹⁸ In the cervical region, pathologic fracture and neurological symptoms may occur at onset as a result of the rapid collapse of bone. Cases of malignant fibrous histiocytoma can be confused with eosinophilic granulomas. However, because of their rapid progression, one should suspect malignancy in these rapidly growing, large, soft tissue masses that occurs during the second and third decade of life. Treatment of fibrous histiocytomas in the cervical region consists of palliative curettage combined with radiation and chemotherapy. Prognosis is poor.

Osteosarcoma

Osteosarcoma is the most common malignant bone tumor but is extremely rare in the spine. Some reported cases of osteosarcoma of the spine are secondary, arising from Paget’s disease, or after radiation therapy.³⁰ If osteosarcoma does occur in the spine, it arises from the vertebral body³¹ or from the posterior elements, but frequently involves the whole vertebra at the time of diagnosis.³² Varied patterns may appear on plain radiographs, ranging from total radiolucent vertebra with collapse and kyphosis to so-called ‘ivory’ vertebra with variable amounts of surrounding neoplastic tissue. The course of the disease is rapid, with early lung metastases. Treatment considerations include intralesional excision combined with chemotherapy and radiation therapy.