disorders: Pathology



Non-mechanical disorders


Pathology



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Osseous disorders



Fractures and luxations


A considerable variety of fractures and dislocations follow trauma between the occiput and the first thoracic vertebra. Most are caused by car accidents, with falls and sports accidents next in frequency.13 Half of all patients present with neurological problems.4


Early diagnosis is important. The cervical fracture is often combined with another spinal fracture and therefore the entire vertebral column must be X-rayed.5 Plain radiographs are the first way in which diagnosis is established. Multidirectional CT is particularly advantageous in patients with facet injuries. CT seems to add most additional information in laminar or posterior column injuries, fractures of the vertebral body or in atlantoaxial subluxations.6



Fractures and dislocations of the atlantoaxial complex


Fractures of the axis are common. In 14–17.5% of all fractures of the cervical spinal column the lesion lies at the axis.7 Most frequent are odontoid fractures. They are classified as type I – avulsion of the tip of the odontoid process, type II – fracture through the base and type III – fracture through the vertebral body.8,9 These are followed in frequency by those of the vertebral body, the pedicle or the lateral mass. Less common is hangman’s fracture – a bilateral fracture through the pars interarticularis of the axis. Neurological damage is not frequent in odontoid and hangman’s fractures but quite common in the other miscellaneous fractures of the axis.10


Dislocations of the atlas are not uncommon and may lead to serious neurological damage.11 Fractures of the atlas are rare and seldom cause neurological problems.


In order of frequency the following fractures are found: bilateral fracture of the posterior arch, comminuted fracture of the ring of the atlas – traumatic spondylolisthesis or Jefferson’s fracture, and unilateral fracture of the lateral mass.12



Fractures of the lower cervical spine


An accident immediately followed by the occurrence of gross limitation of movement in every direction, especially of extension (full articular pattern) strongly suggests vertebral fracture or dislocation. Apart from possible neurological problems the patient presents with severe central or bilateral neck pain and is unable to move his head as the result of muscle spasm. Properly performed radiological examination is diagnostic.


Most fractures in the cervical spine occur below C2. They range from fractures of the articular process to fractures of the vertebral body, lamina, spinous process and pedicle. Fractures are commonly classified in six groups depending (in order of frequency) on the forces that have acted on the cervical spine: compressive flexion, distractive flexion, compressive extension, vertical compression, distractive extension and lateral flexion.13 Neurological problems most often occur when the fracture is combined with luxation.14,15 Pathological fractures following a minor injury or a sudden effort give rise to the same clinical picture but the history is much less indicative and may even be misleading. If neurological injury is present, the diagnosis of a probable fracture or dislocation is made more simple.



Clay-shoveller’s fracture


This is a fracture of one or more spinous processes in the lower cervical or upper thoracic spine (mostly C7, sometimes C6 or T1).16


A traction fracture may occur as the result of strong muscular force from the trapezius transmitted to the spinous processes through the musculature. It happens suddenly. A crack is felt followed by severe pain at the base of the neck and between the shoulders. The same event may occur in motor vehicle accidents where a strong flexion force is applied to the neck, and thus also in whiplash injuries.17,18


If the fracture is the result of a fatigue mechanism, the patient complains of a dull ache at the cervicothoracic junction coming on without clear cause.


Neck movements are not really painful but the patient is unable to bring the arms above the horizontal because of pain. The passive shoulder range is full and painless. The radiograph shows avulsion of one or more spinous processes.


Spontaneous cure takes 3–6 weeks.



Bony tumours


Primary bone tumours are uncommon. They represent only 0.4% of all tumours and cervical localization accounts for only 4.2% of the primary bone tumours of the spine. This is very much less than in the thoracic or lumbar spine.19


Benign primary tumours occur more often in the first two decades of life, while malignant primary tumours more frequently affect adults. The incidence of malignant tumours increases significantly with age. In the cervical spine, even more than in other parts of the axial skeleton, metastatic lesions are much more frequent than primary tumours.


The symptoms may vary and include local heat, tenderness, neuralgic pain, root palsy, torticollis-like limitation of neck movements20 and myelopathy, although early in development the symptoms may mimic ordinary soft tissue lesions. Severe pain at night is often a hallmark of neoplasm.21


The presence of one or more inconsistencies during history and/or functional examination is a warning sign and puts the examiner on guard (see Box 1). It is again mainly the clinical approach that suggests a serious disorder. Radiography – usually the first additional examination – is not always helpful, as it appears that more than 30% of the cancellous bone of the vertebral body must be destroyed before a plain X-ray becomes positive.2224 More refined imaging such as CT scan, technetium scan, angiography and MRI confirms the diagnosis. A radiograph and CT scan of the chest or abdomen may be necessary in patients with unknown primary sites.




Benign tumours


The most common benign neoplasms affecting the cervical spine are, in order of frequency: osteoid osteoma, osteoblastoma, haemangioma, aneurysmal bone cyst, eosinophilic granuloma, giant cell tumour and osteochondroma. They can be found at any level, except C1, and are most common at C2, C4 and C7 levels.2528






Aneurysmal bone cyst

This is seen most frequently in children and young adults, mostly females (under 30 years old).35 Twenty-five per cent of spinal aneurysmal bone cysts are located in the cervical spine.28 It is a destructive tumour and is mostly localized in the neural arch but may also invade the vertebral body. As it expands, it may lead to root pain and even to compression of the spinal cord.


Excision and/or curettage and stabilization with bone grafts are indicated.36






Malignant tumours


The most common malignant neoplasms are: multiple myeloma, chordoma, solitary plasmacytoma, chondroma, chondrosarcoma, lymphoma, osteosarcoma, Ewing’s sarcoma and metastases.


The primary malignant tumours represent 6.3% of all primary bone tumours of the spine and occur mainly from middle age on, much more frequently in men than in women. They are found at all levels, except C1.26




Chordoma

This is an uncommon, locally invasive, slow-growing malignant neoplasm that arises from the vertebral or suboccipital remnants of the embryonic notochord. In 33–38% it occurs in the upper cervical vertebrae, especially C2, and is found most often in men aged between 50 and 70 years.41,42


Central neck pain becoming slowly worse is a common symptom. After several months, movements become gradually limited, especially rotation, with a soggy end-feel on passive testing.


The tumour often extends anteriorly into the soft tissues and may then result in dysphagia, upper respiratory obstruction and Horner’s syndrome.43 Posterior extension may be accompanied by neurological complications, such as epidural spinal cord compression or cervical radiculopathy.44,45


The classic radiological finding is an expanding osteolytic lesion. This life-threatening lesion is best treated surgically by radical resection and, if this fails, repetitive local debulking procedures may be used. The prognosis is bad.






Metastases

Secondary deposits are the most common malignant tumours of the cervical spine, although this part of the vertebral column is the least affected, occurring in 8–20% of patients with known metastatic disease.47 Breast, lung, prostate, colon, kidney and thyroid are the most frequent sites of primaries.48 Metastases in the spine may pass unnoticed for a considerable time and are sometimes discovered during routine radiography.


In symptomatic cases, pain is the earliest and most prominent feature in 90%.49 Localized pain that starts spontaneously and becomes gradually worse, especially at night, is the most common picture of spinal metastases. It is axiomatic that a cancer patient who develops neck pain harbours a spinal metastasis until proven otherwise. If a patient presents with neck pain but has a history of a primary tumour, for example breast cancer, even a long time ago, metastases must be taken into consideration. Tumour-related pain is predominantly nocturnal or early morning pain and generally improves with activity during the day. This pain may be caused by inflammatory mediators or tumour stretching the periost of the vertebral body.50


Neurologic symptoms and signs often begin with radiculopathy (nerve root symptoms) and are followed by myelopathy (spinal cord compression).


The clinical features differ depending on whether the lesion is localized at the upper cervical spine (C1-C3), the lower cervical spine (C4-C7) or the upper thoracic spine (T1-T3).51





Upper thoracic metastases

Limitation of movement is difficult to detect and therefore the situation becomes clear clinically only where a bilateral root pain or root palsy occurs. It should be remembered that weakness of the intrinsic muscles of the hand due to a T1 root palsy is never caused by a disc protrusion. Especially if Homer’s syndrome is also present, a malignant condition is very probable: either a pulmonary sulcus neoplasm or a neoplasm in the upper thoracic vertebrae.


If vertebral metastases are suspected, further investigations are arranged.


Plain radiographs are often ordered as the first test to evaluate a patient with cancer who has neck pain, but are relatively poor screening tests for metastases. Visualization of a radiolucent defect on plain radiographs requires a 30% destruction of the vertebral body. Additionally, metastatic tumour often infiltrates the bone marrow of the vertebral body without destroying the cortical bone. Bone scan (99mTc-MDP) is more sensitive than plain radiographs for detecting spinal metastases. The advantage of bone scan is the ability to screen the entire skeleton with a single image. However, the sensitivity is not 100%: patients with rapidly progressive, destructive tumours may not be detected and bone scan is relatively insensitive for multiple myeloma and tumours confined to the bone marrow.52 It also has a low specificity for tumour: fractures, degenerative disease, and benign disorders of the spine (Schmorl’s nodes, haemangioma) all may be positive.53 Since MRI is widely available, it has become the most sensitive and specific modality for imaging spinal metastases. Sagittal screening images of the entire spine reveal bone, epidural and paraspinal tumour. The extent and degree of spinal cord compression can be readily appreciated.54


The three treatment modalities presently available for spinal metastases are chemotherapy, radiotherapy and surgery (both radical tumour resection and laminectomy).


Jun 5, 2016 | Posted by in ORTHOPEDIC | Comments Off on disorders: Pathology

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