Spine Flashcards

Question

(Ped) 63) A 12-year-old presents with increasing back pain over 2 weeks associated with malaise. He has mild pyrexia. Plain films of the lumbar spine show reduced disc space between the second and third lumbar vertebrae with loss of clarity of the endplates. What investigation would be most likely to help make the diagnosis? a. CT b. MRI c. bone scan d. labelled white cell scan e. gallium scan

Answer 1

b. MRI Discitis is the commonest paediatric spinal disease. It is secondary to bacterial invasion of the disc through the endplate. Plain films typically show reduced disc-space height and loss of clarity of the endplates in the acute phase. MRI is the best investigation, as it is the most sensitive. Reduced T1 signal is seen in the adjacent marrow due to oedema, with initially variable, then increased, T2 signal. Complications such as epidural abscess are well demonstrated. CTwill show the endplate changes and any paravertebral inflammatory mass. Bone scans and white cell scans have much poorer sensitivity than MRI, though this is improved with the use of SPECT.

Answer 2

b. two-column malalignment The spine can be divided anatomically into three columns: the anterior column contains the anterior longitudinal ligament, anterior half of the vertebral body and anterior annulus fibrosus; the middle column contains the posterior half of the vertebral body, posterior longitudinal ligament and the posterior annulus fibrosus; and the posterior column contains the posterior elements of the spine, facet joint capsule and interspinous ligaments. Two intact columns are required for intrinsic spinal stability. Disruption of two columns can therefore be used to infer instability. Usual traumatic patterns are anterior and middle, or posterior and middle, disruption. Isolated middle column interruption can occur after trauma or surgery, or as a congenital abnormality, and is also considered potentially unstable.

Answer 3

a. flowing osteophytes over several vertebral levels The pelvic features are suggestive of diffuse idiopathic skeletal hyperostosis (DISH). Flowing anterior vertebral osteophytes, especially in the lower thoracic region, are very suggestive of this condition, and disc spaces are usually well preserved. Vertebral body squaring is seen in a number of conditions, including ankylosing spondylitis, but not DISH.

Answer 4

b. paracentral L4–5 disc protrusion Degenerative disc disease of the spine is one of the leading causes of functional incapacity and chronic disability in the working population, affecting both men and women. Although there is no universally established nomenclature for describing disc herniation, ‘protrusion’ is commonly used if the herniation is broader than it is deep and ‘extrusion’ if it is deeper than it is broad. A disc ‘bulge’ is used to describe a herniation that is very broad based and may even be circumferential, with a generalised disc bulge being one that affects at least half of the periphery. As a result of the strong posterior longitudinal ligament, posterior disc herniation is often paracentral, i.e. to the side of the midline. This can result in compression of the transiting nerve root in the lateral recess, which is the one that will exit at the level below. A lateral disc herniation narrowing the neural foramen compresses the exiting nerve root. Therefore, for a given intervertebral disc, a paracentral herniation will affect the nerve that exits one level below, whereas a lateral protrusion affects the nerve root at that level.

Answer 5

d. painful osteoid osteoma Percutaneous cement vertebroplasty is a treatment for vertebral compression fractures that involves the injection of acrylic bone cement into the vertebral body in order to relieve pain, stabilize fractured vertebrae or, in some cases, restore vertebral height. Current guidelines from the National Institute for Health and Clinical Excellence (NICE), regarding the use of vertebroplasty in the UK, state that it may be used for pain relief in patients with severe painful osteoporosis with loss of height, compression fractures of the vertebral body, symptomatic vertebral haemangioma and painful vertebral body tumours (metastases or myeloma). Review of current evidence indicates some level of pain relief in 58–97% of patients.

Answer 6

e. convex posterior border to the vertebral body A convex bulge involving the whole posterior border of the vertebral body strongly suggests vertebral body expansion by tumour invasion, and is only very rarely a feature of osteoporosis. Other findings on MRI suggestive of malignancy include a soft-tissue mass, involvement of the pedicles, and heterogeneous high signal on T1W post-contrast or T2W images. Retropulsion of bone fragments, focal T1 low signal or an isointense appearance on T1W or T2W images suggests osteoporotic collapse.

Answer 7

c. intermediate signal posterior to the vertebral body on T1W images Intermediate signal in the extradural space on T1W images is the most common appearance of extradural abscess formation. The most common primary focus of infection is discitis, but abscess formation may also be spontaneous. Patients particularly at risk are those with a history of diabetes mellitus, intravenous drug use, trauma, haemodialysis or recent surgery (particularly dental). MRI features of extradural abscess include iso- or slight hyperintensity on T1W images when compared with the spinal cord. High signal on T2W and proton density sequences makes it difficult to differentiate abscess from CSF, but these sequences are useful, as osteomyelitis and paravertebral abscess are well visualized as high-signal lesions. Administration of intravenous gadolinium contrast characteristically demonstrates diffuse enhancement of the solid component of the abscess.

Answer 8

b. multiple myeloma Multiple myeloma is a malignant condition of plasma cells that commonly shows infiltration of the bone marrow, best seen on MRI. Patterns of infiltration can be classified as focal, diffuse or variegated. Although marrow infiltration returns similar signal to marrow oedema on T1W and T2W images, infiltration will show diffuse enhancement following administration of intravenous gadolinium. The pattern of infiltration also differs. Infiltration will be patchy and randomly distributed throughout the vertebral bone. In contrast, bone oedema occurs adjacent to its cause, being linear at the endplates in the case of degenerative disc disease, and linear with a fracture line in osteoporotic collapse, in the pedicles adjacent to spondylolysis or at the entheses in ankylosing spondylitis.

Answer 9

d. tethered cord Tethering of the cord results in the conus lying lower than normal and is associated with scoliosis, thickening of the filum terminale (>2 mm at the L5-S1 level on axial T1 image) and spinal lipoma. Less frequent associations are Chiari malformations, syrinx, myelomeningocele, diastematomyelia and dermal sinus. Diastematomyelia is a midline sagittal cleft in the cord, often with a bony/fibrous septum. Syringomyelia is dissection of cerebrospinal fluid through the cord, producing high T2 signal within the cord. This is associated with several neurological abnormalities. Developmental scoliosis occurs in adolescent girls, is convex to the right and has no associated neurological symptoms.

Answer 10

d. chordoma Chordomas arise from notochordal rests and therefore almost always occur in the midline. They are the most common primary malignant sacral tumour and account for 2–4% of all malignant tumours of bone. They are found at all ages but most commonly occur in the fourth to seventh decades of life. Approximately half develop in the sacrococcygeal region. There is usually a large soft-tissue component and the tumour may extend across the intervertebral disc space or sacroiliac joint. Overall, the most common sacral lesion is metastasis due to the high red marrow content, but other primary malignant lesions include myeloma, Ewing’s sarcoma and lymphoma. The most commonly found benign tumours are giant cell tumours and aneurysmal bone cysts. Despite being relatively common in the rest of the spine, haemangiomas and osteoid osteomas are rare.

Answer 11

(d) Meningioma Of the listed options, only nerve sheath tumours, meningiomas and leptomeningeal metastasis are typically intradural and extramedullary (chordomas are extradural and astrocytomas are intramedullary). Although nerve sheath tumours are more common, meningiomas are more likely if the tumour is solitary, posterior and does not contain areas of low signal intensity on T2W

Answer 12

(b) On the lateral view, the soft tissues anterior to C2 are 9 mm thick The distance between the anterior arch of C1 and the anterior aspect of the odontoid peg should be no more than 3 mm in an adult. On the lateral view, the maximum width of the prevertebral soft tissues is: 7 mm at C1-4, 22 mm at C5-7. Harris' ring is often incompletE;i in its inferior aspect. On the long AP view, no single interspinous distance should be more than 50% wider than the one immediately above or below it.

Answer 13

(e) Scheuermann's disease Scheuermann's is thought to be caused by herniation of disc material through congenital end-plate defects during the adolescent growth spurt (presents 13-17 yrs). It accounts for 31 % of cases of back pain in adolescent boys and is located in the thoracic (75%) or thoracolumbar spine (25%). At least one vertebral body needs to be involved with anterior wedging of >5° (usually 3-5 are involved), and there must be kyphosis of >35°. The posterior aspect of the vertebral body is protected by posterior articulation. The other listed conditions are potential causes of kyphosis in children.

Answer 14

(a) Type I This is a type I malformation, also known as diastematomyelia. A type II of malformation comprises two hemicords within a single dural tube, also known as diplomyelia. There is no type III, IV or V malformations.

Answer 15

(b) Type I Modic change Modic degenerative changes are bone marrow and endplate changes adjacent to degenerative lumbar intervertebral discs; they are commonest at the L4-L5 and L5-S1 level. Modic II is more prevalent, but Modic I changes are more likely to be symptomatic. Type I changes have MRI appearances of fluid (low T1, high T2), type II changes have the characteristics of fat due to red marrow replacement (high T1 and T2), and type Ill changes are due to sclerosis (low on T1 and T2).

Answer 16

(e) Vertebral body involvement is more common than the posterior elements GCTs are usually benign lesions. Malignancy occurs in 5-10°/o of cases and is usually secondary to previous radiation therapy. The majority of spinal lesions arise within the sacrum. Vertebral involvement accounts for only 7% of cases: thoracic spine is the most common location, followed by cervical and lumbar regions. They typically increase in size during pregnancy, thought to be due to hormonal influences. GCTs tend to be locally aggressive and complete surgical resection is uncommon; adjuvant radiotherapy is often administered. Recurrence occurs in 40- 60%, and is suggested on plain film by the presence of new areas of osseous destruction.

Answer 17

(b) This is a stable dislocation Given the extent of anterolisthesis (>50% of a vertebral body), this is most likely to represent bilateral, rather than unilateral facet dislocation, and therefore an unstable injury.

Answer 18

(a) Type I This is a spinal dural AV fistula (type I), the fistula is present within the dura, producing distended draining veins on the pial surface and cord oedema secondary to venous hypertension.

Answer 19

(a) Annular disc bulge In an annular disc bulge, disc tissue extends beyond the adjacent vertebral bodies by at least 3mm for more than 50% of the disc circumference. This is associated with degenerative disease and is not regarded as a true herniation.

Answer 20

(d) Fractures involving the posterior elements Other absolute contraindications include bleeding diathesis, acute fractures not responding to bisphosphonate treatment within 2 weeks and those where the level of collapse cannot be clearly defined.

Answer 21

(e) Metastasis is common Chordomas arise from notochord remains and are therefore limited to the clivus, spine, sacrum and coccyx. Metastasis is uncommon, but when it does occur, lung secondaries are typical. Tumour size (the average size of a sacrococcygeal chordoma is 10 cm), lytic nature and location are important clues to the diagnosis.

Answer 22

(c) Flexion teardrop fracture Neutral films infer stability based on fracture type; stability is a function of ligamentous injury and thus cannot be implied with 100% accuracy, if doubt remains MRI or flexion/ extension views should be obtained. The other type of unstable flexion injury is a bilateral facet joint dislocation. Unstable extension injuries include Hangman's fracture and hyperextension-dislocation fracture; stable extension injuries include posterior arch of C1 fracture, laminar fracture, Pillar fracture, and extension teardrop fracture. Jefferson's fracture is an unstable compression fracture, burst fracture a stable one. 'Complex' unstable fractures include odontoid fracture and atlanto-axial disassociation.

Answer 23

(d) Lucent line in C3 spinous process Cervical spine injuries in children are usually located between the occiput and C2-C3, because the spine is hypermobile (ligament laxity), there is incomplete ossification of the odontoid process, a relatively large head, and weak neck muscles. The other options are normal variants, others include absent cervical lordosis, intervertebral widening, and pseudospread of the atlas on the 'Peg' view (pseudo-Jefferson fracture). Pseudo-widening of the prevertebral soft tissues can be normal, related to expiration.

Answer 24

(c) III Spondylolisthesis is graded from I-IV with each grade corresponding to 25% of displacement.

Answer 25

3. c. Retropharyngeal space of 10mm This is too wide for the retropharyngeal space. The correct acceptable limits for soft-tissue measurements are as follows: _ Predental space 3mm in adults, 5mm in children. _ Nasopharyngeal space (anterior to C1) 10 mm. _ Retropharyngeal space (C2–C4) 5–7 mm. _ Retrotracheal space (C5–C7) 22 mm. Disc spaces should be roughly equal throughout the cervical spine. Narrowing of a disc space is due to degenerative change, but widening would be a more concerning feature.

Answer 26

5. c. Astrocytoma Astrocytoma of the spinal cord is the most common intramedullary neoplasm in children. They most commonly occur in the thoracic region (thoracic 67%, cervical 49%, conus medullaris 3%). The most common presentation is with pain and sensory deficit but they can also present with motor and gait abnormalities. Plain radiographs may demonstrate scoliosis, bone erosion and widened interpedicular distance. On MRI, the lesion is usually seen as an eccentric, homogeneous, extensive, ill-defined cord tumour that is iso- or hypointense to the cord on T1 and hyperintense in T2. There is patchy irregular gadolinium enhancement. Tumour cysts and syrinx are also common. Patients with low-grade astrocytomas have a 95% five-year survival. It is often difficult to differentiate an astrocytoma from ependymoma of the spinal cord on imaging. In this case, the age of the patient, tumour location, tumour irregularity and **eccentric position within the medullar** favour astrocytoma.

Answer 27

13. e. Haemangioma This is most likely to be a benign haemangioma. These are relatively common lesions seen as incidental findings on spinal imaging. High signal on T1 imaging is indicative of the presence of fat within the lesion. All the other conditions would give a low-signal lesion on T1 imaging.

Answer 28

18. c. Jefferson fractures are usually associated with a neurological deficit Jefferson fractures are not usually associated with neurological deficit. Although there may be retropulsion of fragments into the vertebral canal, spinal cord injury is rare due to the large dimensions of the canal at this level. Vertebral artery injury, however, must be considered and if there is concern either CTA or MRA imaging should be considered.

Answer 29

27. d. Right L5 The right L5 nerve root is the most likely to be affected as it will be sitting in the right lateral recess at the L4/5 level. The L4 nerve root will be at the exit foramen and therefore if the protrusion affects only the lateral recess then this nerve will already have exited and therefore not be affected.

Answer 30

34. b. Flexion This describes the typical appearance for a flexion injury as well as the typical mechanism. This would represent a potentially unstable fracture and immobilisation would be essential until further management decisions are made. Flexion teardrop injuries are more common in the lower cervical spine and extension teardrop injuries are more common in the upper cervical spine

Answer 31

47. c. Devic syndrome (DS) Devic syndrome (neuromyelitis optica (NMO)) is a severe demyelinating syndrome characterized by optic neuritis and acute myelitis. There is substantial evidence that DS is distinct from multiple sclerosis (MS). DS may spare the brain, the spinal lesions are much larger than in MS and the serum autoantibody NMO-IgG is greater than 90% specific for DS patients and is not detected in classical MS patients. The proposed diagnostic criteria for Devic syndrome are optic neuritis and acute myelitis plus at least two of three supporting criteria: 1. Contiguous S.cord MRI lesion extending over > or equal to three vertebral segments. 2. Brain MRI not meeting diagnostic criteria for multiple sclerosis. 3. NMO-IgG seropositive status.

Answer 32

47. e. Spheno-occipital chordoma The most likely cause is a spheno-occipital chordoma. This is associated with bony destruction in 90% of cases and is most usually within the clivus. Other sites include the sella, petrous temporal bone, floor of middle cranial fossa and jugular fossa. Sacrococcygeal chordoma is the most common subtype of chordoma and is usually located with the fourth or fifth sacral segments. Vertebral/spinal chordoma accounts for only 15–20% of all chordomas & is most often situated in cervical spine.

Answer 33

50. c. MRI C spine MRI should be the next investigation in a child of this age group. A ligamentous injury is more likely and therefore CT of the C spine may be falsely reassuring. However, in some centres the availability of MRI may be limited and a CT will often be performed in the first instance. Flexion/extension views should not be done in the acute setting. A trauma oblique view is performed in some institutions instead of a swimmer’s view & may be used to clear the cervicothoracic junction in particular.

Answer 34

51. e. A 7mm gap between the occipital condyles and the condylar surface of the atlas This is highly suggestive of craniocervical injury; these injuries are often fatal and are often caused by sudden deceleration. Radiologic evaluation of this injury can be difficult but is crucial in determining further management. The remainder of the findings above can all be normal variants in the paediatric cervical spine and therefore should be interpreted with care.

Answer 35

52. c. Arachnoiditis Arachnoiditis is an intrathecal inflammatory reaction which usually results from iatrogenic injury. Previously, it was associated with the injection of contrast agents during myelography. Now, it is most commonly seen following lumbar surgery. Intradural infections (TB, fungal, parasitic) are rare causes. Radiologically, arachnoiditis appears as nerve root adhesion. Commonly the nerves are clumped together simulating a solid mass, although the nerves may also adhere to the dura, giving the appearance of an ‘empty thecal sac’. In severe cases, the thecal sac may become loculated and compartmentalised. Clumped nerve roots suggest arachnoiditis and the lack of enhancement makes tumours unlikely.

Answer 36

56. d. Tuberculosis The vertebral column is the most common site of osseous involvement of tuberculosis (TB), usually as the result of haematogenous spread from pulmonary involvement. The lower thoracic and upper lumbar vertebrae are the most frequently affected. It can be difficult to differentiate between pyogenic and TB spondylodiscitis on imaging but several features favour a diagnosis of TB: multilevel involvement/skip lesions, relative sparing of the disc spaces, large pre/paravertebral collections which are more likely to calcify, subligamentous spread and meningeal involvement

Answer 37

A Compression

Answer 38

C Focal high T2 signal within the spinal cord with mild cord swelling These are the expected findings in spinal cord infarction and this clinical history is typical

Answer 39

C The distance between the anterior arch of Cl and the dens can be up to 5 mm. Children may also get spinal cord injury without radiographic abnormality (SCIWORA) as the ligaments are lax; therefore, MRI may be necessary.

Answer 40

E Neurinoma Neurinomas and meningiomas are the commonest intradural extramedullary tumours. Neurinomas may occur at any level whereas meningiomas tend to be thoracic and are very rare in the lumbar spine.

Answer 41

E Synovial cyst Synovial cysts may be solid with cartilaginous or myxomatous components

Answer 42

C Large paravertebral abscess It is not possible to reliably differentiate between pyogenic and tuberculous spondylitis but some features may be helpful. Pyogenic infection tends to be rapidly progressive, whereas tuberculous infection is more insidious. In pyogenic infection there is a marked sclerotic response; bridging of affected vertebrae is an early sign but vertebral collapse and paravertebral abscesses are not prominent features. In tuberculous infection a large paravertebral abscess (which may contain calcification) is a more common finding and there is typically marked vertebral body collapse but less bony sclerosis.

Answer 43

A Anterior wedge fracture

Answer 44

B Doubles the risk of a proximal femoral fracture Vertebral fractures are not only the most common fragility fracture, but also serve as powerful predictors of subsequent fracture. A vertebral fracture increases the likelihood of a further vertebral fracture fivefold, and doubles the risk of subsequent femoral neck fracture.

Answer 45

E Jefferson's fracture

Answer 46

B Bifid vertebrae This describes diastematomyelia which has several associations, including hemivertebrae and bifid vertebrae.

Answer 47

B Limbus vertebra

Answer 48

A Klippel-Feil syndrome Sprengel deformity of the scapula is a recognised association of Klippel-Feil syndrome.

Answer 49

A Arachnoiditis Arachnoiditis may be iatrogenic or may occur due to intradural infections, trauma, spinal subarachnoid haemorrhage and rarely intraspinal tumours.

Answer 50

B Infection Infection is the commonest cause of unilateral sacroiliitis, and TB should be considered as a possible organism. Ankylosing spondylitis and osteitis condensans ilii have symmetrical appearances, whilst Reiter's syndrome is bilateral (but asymmetric). Psoriatic arthropathy produces bilateral disease, which is symmetrical in most cases.

Answer 51

4. E. Atlanto-axial impaction. This is a more severe form of atlanto-axial subluxation where the C1-2 facets collapse and there is invagination of the dens of C2 into the foramen magnum. As such, the dens is not visible on the lateral radiograph. The key feature, apart from widening of the pre-dental space (which can also be caused by pannus eroding the dens or more commonly atlanto-axial subluxation), is that the anterior arch of C1 lies in front of the lower portion of C2, whereas it normally lies anterior to the dens.

Answer 52

26. D. Paraganglioma. Paragangliomas are rare intradural extramedullary tumours that are usually benign and haveimaging characteristics as those described. Schwannomas, neurofibromas, and meningiomas aremuch more common, but do not typically contain vascular flow voids or areas of haemorrhage. Meningiomas may have a dural tail or foci of calcification. Schwannomas and neurofibromascan be difficult to distinguish on imaging. They are typically isointense on T1WI and markedlyhyperintense on T2WI. Enhancement may be intense and homogenous or peripheral.Neurofibromas tend to encase, rather than displace, nerve roots.Leptomeningeal metastases present with three different imaging patterns: 1) Diffuse, thin enhancing coating of the surface of the spinal cord and nerve roots. 2) Multiple small enhancing nodules on the surface of the cord and nerve roots. 3) A single mass in the lowest part of the thecal sac.

Answer 53

1. C. Chordoma. Plain film is very insensitive for detecting sacral lesions. Metastatic disease is much more common in the sacrum than primary malignancy. Chordoma is the most common primary sacral lesion. It is derived from the embryonic remnants of the notochord and is thus almost always found in the midline or a paramedian location with respect to the spine. It is most commonly found in the sacrum (50%), clivus (35%), and vertebrae (15%). A chordoma manifests as a destructive, lytic lesion, commonly with internal calcifications, at both plain radiography and CT. A large presacral soft-tissue component is usually present, as are soft-tissue components within the sacrum and sacral canal. Symptoms can include pain, sciatica, and rectal bleeding as well as other bowel and bladder symptoms, reflecting compromise of sacral nerves. The tumours can extend across the adjacent disc space and sacroiliac joint. On MRI, chordomas demonstrate low to intermediate signal intensity on T1WI and prominent increased signal intensity on T2WI. Enhancement of the soft-tissue components is variable, yet often moderate, on both CT and MR images. Chordomas demonstrate a prominent vascular stain at angiography. They are locally aggressive and develop in locations that do not permit easy surgical cure. There is an almost 100% recurrence rate; tumour seeding along biopsy tracts and surgical incisions can lead to multicentric local recurrences. Metastasis occurs in 5–43% to liver, lung, regional lymph nodes, peritoneum, skin, and heart. The 5-year survival rate is 66% for adults. Osteomyelitis in the sacrum is most often due to contiguous spread from a suppurative focus and we are told this patient was previously well. Ewing sarcoma would occur at a younger age (peaking at 15 years, 90% manifest between the ages of 5 and 30). In the case of myeloma it would be atypical for the rest of the spine to be uninvolved. The sacrococcygeal region is the most common location of teratomas discovered in infancy. It is only rarely discovered in adulthood. Teratomas are composed of a mixture of cystic and solid components. The other lesions to be included in the differential diagnosis of such a sacral mass are metastasis, sarcomas, GCT, chondrosarcoma, and ependymoma.

Answer 54

27. E. Ependymoma. Ependymoma is the most common intramedullary neoplasm in adults. It tends to be centrally located within the cord, unlike astrocytoma, which can be eccentric. Astrocytoma can have alonger segment of cord involvement than ependymoma and may have a more infiltrative margin. The peripheral low signal areas seen on T2WI in ependymoma are related to haemosiderin deposition from prior haemorrhage. Haemangioblastoma is more often seen in the dorsal cord than the cervical cord and is typically a small well-defined lesion. It may have an associated cord cyst or syrinx. Flow voids may be seenwithin the lesion, from dilated vascular channels. Ganglioglioma is a very rare, slow-growing tumour of low malignant potential. The imaging appearance is non-specific, but there are some findings that may suggest the diagnosis. Compared with other spinal cord tumors, gangliogliomas are more likely to involve long segments of thecord (greater than four levels, up to the whole cord), to be associated with bone erosion orscalloping, to have tumoral cysts, and to have areas of mixed high signal on precontrast T1WI. Intramedullary metastasis represents less than 5% of intramedullary lesions. They usually occur inthe setting of advanced malignant disease, typically from a lung or breast primary. The spinal cord oedema can seem out of keeping with the small size of the metastatic lesion.

Answer 55

27. C. An atlanto-dens interval (ADI) of 6 mm. There are appearances that are normal for a paediatric cervical spine, which would be considered pathological in an adult and of which it is important to be aware. Pseudo-subluxation at C2/3 and C3/4 is common (it was observed in 46% of patients less than 8 years old at C2/3 in one study and has been seen up to 14 years). The anterior aspects of the spinous processes of C1, C2, and C3 should line up within 1 mm of each other on flexion and extension (assessed by drawing the posterior cervical line, a line from the anterior aspect of the spinous process of C1 to the equivalent point at C3). The anterior aspect of the spinous process of C2 is allowed to pass through, touch, or lie up to 1 mm behind the posterior cervical line in physiological subluxation. The normal ADI (the distance between the anterior aspect of the dens and the posterior aspect of the ring of the atlas) in adults is 3 mm, but is normal up to 5 mm in children. ‘Pseudo-Jefferson’ fractures (pseudospread of the lateral masses of C1 on C2) can be seen on the peg view, and up to 6 mm of displacement is common up to 4 years old and may be seen in patients up to 7 years old. Anterior wedging of up to 3 mm of the vertebral bodies should not be confused with compression fracture. This finding can be profound at C3. Prevertebral swelling of 6 mm or less is considered normal at C3. Widening of prevertebral soft tissues in children can be due to expiration, and if suspected, a repeat lateral film in inspiration and mild extension should be performed.

Answer 56

48. D. Eccentrically placed lesion in the cord. Table 6.2 illustrates the diagnostic features ofastrocytoma and ependymoma

Answer 57

49. E. Meningioma. Spinal meningiomas are typically iso- to hypointense on T1WI and slightly hyperintense onT2WI. There is usually strong and homogeneous enhancement with gadolinium. However, some meningiomas may contain calcification and are typically the only intradural extramedullarytumours to do so. Some meningiomas can be heavily calcified and such a meningioma is being described in the question. These will remain dark on all MRI sequences and demonstrate onlylittle contrast uptake (in the non-calcified areas). Schwannomas, neurofibromas, and metastases would not typically be hypointense on T2WI. Meningeal lymphomas are very rare and usually manifest as diffuse thickening of nerve roots and/or multiple enhancing nodules.

Answer 58

50. C. T2 fast SE. T2 fast SE is probably the least useful sequence when specifically looking for vertebral marrow deposits because the metastases are less conspicuous, typically being high signal on a background of high-signal fatty marrow. On STIR and T2 fast SE with fat saturation, the metastases typically stand out as being of increased signal on a background of dark marrow because of the fat saturation techniques. On T1 fast SE sequences, the metastases typically stand out as being lowsignal on a background of high-signal fatty marrow. Finally, T1 GE out-of-phase imaging is also good for looking for vertebral metastatic disease. This is a sequence with a specific echo time corresponding to the time it takes for water and fat protons to move exactly 180° out of phase. In the normal adult human, the medullary bone of the vertebral bodies contains approximately equal amounts of water and fat protons. In out-ofphase conditions, the signal of both will cancel out, leaving the vertebrae completely black. In the case of vertebral pathology, however, the signal will increase and, as such, vertebral metastases (or other lesions) will clearly stand out.

Answer 59

53. F The variable proportions of vascular and fatty soft-tissue elements influence the MRI appearance of haemangiomas. Lesions with a predominantly fatty matrix show high signal intensity on T1WI, intermediate to high signal intensity on T2WI, and loss of signal on STIR or fat-suppressed T2WI. If the vascular elements predominate, the lesions appear hypointense on T1WI and extremely hyperintense on STIR and T2WI. If MRI is inconclusive, CT may be helpful in identifying the typical pattern of haemangiomatous bone replacement, such as the honeycomb, ‘soap bubble’ or ‘sunburst’ appearance.

Answer 60

6 Answer E: Atlantoaxial subluxation Hypoplastic posterior arch of C1 and abnormal odontoid peg can also be found in Down's syndrome but with the clinical history this child is most likely to have atlantoaxial subluxation.

Answer 61

35 Answer C: Bilateral facet dislocation This injury is inherently unstable, in contrast to unilateral facet dislocation. Severe flexion forces in combination with distraction result in complete disruption of the facet joints and displacement of the vertebral body by at least 50% relative to the one below it. A significant number are associated with traumatic disc herniation. Initial closed reduction and traction is required, but should be done judiciously as it is possible for a disc herniation to retropulse into the cervical canal.

Answer 62

37 Answer B: Haemangioma Haemangiomas are confined to trabecular bone. Their characteristic appearance is due to resorption of trabeculae by enlarged vascular channels and thickening of the remaining trabeculae.

Answer 63

60 Answer B: Cervical spine Almost two-thirds occur in the cervical spinal cord with one-third of these showing extension to the thoracic cord. They usually extend over multiple segments (three or four on average).?

Answer 64

60 Answer A: A line between the anterior margins of Cl and C3 spinous processes passing within 2 mm of the anterior margin of the C2 spinous process Pseudosubluxation is normal mobility of the upper cervical spine, particularly at C2/3 and C3/4, which occurs in approximately 40% of children younger than eight years old. It results from immature lax ligaments and horizontally aligned facets. Swischuck's line, drawn between the anterior margins of the spinous processes of Cl and C3, should pass through or lie within 2 mm of the anterior margin of the spinous process of C2. More than 2 mm is suggestive of pathological subluxation. In pseudosubluxation the anterior displacement occurs in flexion and should reduce with neck extension.

Answer 65

63 Answer E: Right L4/L5 lateral disc bulge Intervertebral disc herniation and degeneration is the most common source of compressive radiculopathy. The lumbar roots emerge from below their respective vertebrae. Different nerves are compressed depending on the location of the disc protrusion. To avoid confusion, nerve roots are designated as `exiting' and `descending/ traversing' nerve roots. The exiting nerve is the nerve leaving the spinal canal through the neural foramen below the pedicle of the vertebral body sitting on top of the disc. At each intervertebral disc level, there is usually only one spinal nerve root outside the dural sac in the spinal canal descending behind the intervertebral disc to exit below the pedicle of the vertebral body forming the lower surface of that disc. At the L4-L5 disc, for example, the exiting nerve would be the L4 nerve, which usually leaves the dural sac at about the level of the lower part of the body of L3, descends behind the L3-L4 disc, and exits the spinal canal below the pedicle of L4 through the top of L4-L5 neural foramen. The descending nerve would be the L5 nerve root.

Answer 66

64 Answer C: Basilar invagination McGregor's line extends from the posterior limits of the hard palate to the base of the occipital region. The odontoid peg should lie 5 mm below this level. If it is at the level of the McGregor's line, this is basilar invagination. Causes of basilar invagination are rickets, osteomalacia, fibrous dysplasia and developmental such as Klippel-Feil. Platybasia is flattening of the skull base and it commonly occurs with basilar invagination. The basal angle is greater than 140 degrees in platybasia

Answer 67

64 Answer E: Vertebral body Usually in upper lumbar/lower thoracic spine. Rarely may bulge posterior cortex or extend into spinal canal leading to cord compression.

Answer 68

65 Answer C: Normal pedicles Features that are suggestive of a bony metastasis are: a bowed posterior border of the vertebral body, abnormal signal in the pedicles, an epidural or paraspinal mass and multiple lesions. Features suggestive of osteoporotic wedge fractures are: low signal on both Ti- and T2-weighted imaging, spared normal marrow signal and multiple compression fractures.

Answer 69

66 Answer C: Ependymoma Ependymomas are the most common primary spinal cord tumour. They most commonly occur in the cervical region followed by the thoracic region and extend over a large area (average of four vertebral bodies). They are well-defined and central lesions. They often have a low signal rim around the outside due to haemosiderin from repeated bleeds. As they are slow-growing tumours they are ass with bone remodeling, mets to lung, retroperitoneum & LN . There is an 80% 5 Y survival.

Answer 70

67 Answer B: Metastatic breast cancer Drop metastases are most commonly seen in the paediatric population and are most commonly due to PNETs, medulloblastomas, ependymomas, germinomas and pinealoblastomas. In adults metastatic breast and melanoma are common causes. The above description is very typical. Irregularity along the surface can also be seen.

Answer 71

68 Answer E: Chordoma This is a typical description of a sacral chordoma. Chordomas originate from embryonic remnants of the notochord. They arise in patients aged between 30 and 70 years of age and are more common in males. The most commonly occur in the sacrum then the clivus. They metastasise to the liver, lung and lymph nodes and tend to recur despite radical surgery.

Answer 72

69 Answer C: Spinal cord cavernous angioma Spinal cavernomas are uncommon, unlike cerebral cavernomas. They typically present in women (M:F = 1:4) between 30 and 50 years of age and are most common in the cervical and thoracic regions. They are intramedullary lesions, which are well defined and are bright on both Ti and T2 as they contain methaemaglobin. Blooming artefact is present because of the presence of haemosiderin from previous bleeds. Little mass effect is seen. A common presentation of spinal cavernomas is with Brown-Sequard syndrome (hemiparaplegia, ipsilateral loss of proprioceptive sensation, hyperesthesia and contralateral loss of pain and temperature). Progression of symptoms is common.

Answer 73

25 Answer E: CT head and cervical spine Multidetector CT with coronal and sagittal reformatting is now commonplace and the gold standard for cervical spine trauma.

Answer 74

28 Answer A: Diastematomyelia Diastematomyelia is characterised by a developmental sagittal cleft, which splits the spinal cord or filum terminale. The septum is either bony, osteocartilagen- ous or fibrous. This usually occurs between T9 and Si and has a distinct female preponderance. It is associated with other anomalies including Chiari II, tethered cord, neurenteric cyst and dermoids.

Answer 75

30 Answer D: Clay-shoveller's fracture A clay shoveller's fracture is a stable fracture of a lower cervical vertebra spinous process, usually C7. The mechanism is sudden flexion of the neck combined with a heavy upper body and lower neck muscular contraction. This causes avulsion of the spinous process by the supraspinous ligament. A similar fracture may also occur with direct blows to the spinous process or with occipital trauma causing forced flexion of the neck. The remaining fractures are all potentially unstable.

Answer 76

32 Answer A: Vertebral body The most common site for metastatic involvement is the anterior aspect of the vertebral body. Increased uptake in the posterior elements and especially facet joints is more suggestive of degenerative change.

Answer 77

39 Answer D: Hyperflexion Hyperflexion injury of the spine accounts for 46-79% of all cervical spine injuries. The anteroinferior teardrop fracture is the most severe and unstable injury of the spine. The widening of the posterior elements indicates disruption of the posterior ligament complex. It is an unstable injury, which results in ligamentous damage and spinal cord compression. Typically, these occur at C6 to C8. Hyperflexion injuries are the most common injury accounting for between 50 and 75% of injuries. The anterior height of the vertebral body is reduced with anterior reduction in disc space and there is diffuse prevertebral soft-tissue swelling. Extension teardrop fractures occur at the anteroinferior corner of C2 and this may occur in isolation or with a hangman's fracture. Here there is widening of the anterior disc space.

Answer 78

40 Answer B: Klippel-Feil syndrome Klippel-Feil syndrome is caused by failure of normal segmentation of the cervical vertebrae. Features include a short neck, low hairline and reduced mobility of the upper spine. Any of the cervical vertebrae can be involved but fusion of the C2/C3 vertebrae is the most common.

Answer 79

41 Answer D: Giant cell tumour (GCT) GCTs are characteristically well defined with a non-sclerotic margin and are most frequently seen in young adults aged between 20 and 40 years. Most GCTs occur in the long bones, but a number do occur in the spine where they tend to affect younger patients and to be three to four times more common in the sacrum than rest of spine.

Answer 80

46 Answer A: Location in the posterior elements An osteoblastoma is histologically identical to an osteoid osteoma but usually larger and the classical description is of a well-defined expansile lesion in the posterior elements of the spine. Around 80% of cases present before 30 years of age and a sclerotic rim is usually present. There is, however, a wide variety of possible appearances including cortical thinning and a soft-tissue mass which can resemble a malignant process.

Answer 81

55 Answer B: Loss of anterior vertebral height and Schmorl's nodes Scheuermann's disease or adolescent kyphosis is the second most common paediatric spinal deformity, which has its onset at puberty. In the forward flexed position there is abrupt angulation in the mid to lower thoracic region. Additional radiographic features include disc space narrowing, end plate irregularities and kyphosis >40 degrees.

Answer 82

60 Answer D: Ependymoma The lesion described is extradural in location. Extradural masses arise from outside the spinal dura and may originate from the vertebral body, disc and adjacent soft tissues. On MR dura may be seen draped over the mass, and sometimes epidural fat may be seen capping the lesion. Intradural, extramedullary lesions arise inside the thecal sac, but outside the cord and originate from the nerve roots, meninges and CSF spaces. On MRI, intradural lesions are clearly delineated by CSF and the cord is deviated away from the lesion. The subarachnoid space is enlarged up to the mass. Intramedullary masses arise inside the spinal cord and originate from the cord parenchyma or pia. On MRI there is diffuse enlargement of the cord with gradual effacement of the subarachnoid space.

Answer 83

60 Answer C: Thoracic spine Almost two-thirds occur in the thoracic spinal cord, although half involve the cervical cord as they usually extend over a long region of cord (approximately seven segments on average).

Answer 84

61 Answer C: Astrocytoma The commonest intramedullary lesions are astrocytoma and ependymoma. Astrocytomas are the most common cord tumour in children and the cervical cord is the commonest location followed by the thoracic cord. Multisegmental involvement is common and they are often associated with a syrinx and cysts. Despite being low grade they tend to enhance strongly with contrast. Ependymomas are more common in adults and occur in the conus medullaris and filum terminale. They are generally slow growing and cause vertebral body scalloping. Cysts and haemorrhage are common.

Answer 85

62 Answer E: Haematoma Spinal haematomas occur due to trauma, following a procedure (typically laminectomy or epidurals), during childbirth or spontaneously, particularly in those with bleeding disorders. They are usually due to venous bleeds and are typically posterior fusiform masses. They can result in a cauda equine syndrome and require prompt neurosurgical evacuation.

Answer 86

64 Answer B: Von Hippel-Lindau syndrome with haemangioblastoma and renal cell carcinomas A third of all spinal haemangioblastomas occur in patients with VHL. They are the third most common intramedullary neoplasm. They are usually intramedullary but can be extramedullary (25%) and occur most commonly in the cervical (40%) and thoracic (50%) regions. Patients present with a prolonged history of sensory and motor symptoms. They are highly vascular lesions, which are isointense on Ti, high signal on T2 with multiple signal voids and bright enhancement with contrast. Low signal from haemosiderin is often seen on T2*.

Answer 87

66 Answer B: Tethered cord Tethered cord usually presents in children with bowel and bladder dysfunction and lower limb neurology. It is slightly more common in females. Fifty per cent of patients have a hairy patch overlying the lower back. It can be associated with filum lipoma, imperforate anus, filum cysts and diastematomyelia. The main features are low-lying cord and thickened filum terminale (greater than 2 mm). Patients are treated with a decompressive laminectomy. At birth the corms medullaris should lie at L2/3 and at L1/2 at three months.

Answer 88

67 Answer E: Flexion extension views of lumbar spine Pars defect is a fracture through the pars interarticularis. These are due either to a stress fracture, congenital or secondary to other condition; for example, tumours, osteomalacia or Paget's disease. Spondylolysis commonly occur at the L5 vertebra. Neurology typically occurs after a degree of spondylolisthesis. If on imaging no nerve root impingement is seen but the history is typical, this might be because the slip is unstable and so flexion extension films should be performed.

Answer 89

68 Answer B: Traumatic nerve root avulsion The right Ti nerve root has been avulsed. This most commonly occurs in the cervical region following severe acute traction on the upper limb such as a fall from a motorbike. Imaging typically demonstrates an absent nerve root within the neural foramina and a pseudomeningocele. If patients are not able to have an MRI, a CT myelogram could be performed.

Answer 90

69 Answer A: Tarlov cyst A Tarlov cyst is a perineural cyst arising from the nerve root. They most commonly occur in the sacral region and can cause bone scalloping from pressure effects. It is postulated that there is a ball valve effect so CSF flows into the cyst with arterial pulsations. The spinal nerves may be visualised either in the wall of the cyst or the cyst itself. They occur in 5 % of the population and are more common in women. They are usually asymptomatic but may cause symptoms such as bladder and bowel dysfunction or lower motor or sensory abnormalities.

Answer 91

2 Answer E: Lumbar myelomeningocele The child has Arnold Chiari malformation (Chiari II malformation), which has the above characteristic features. It is associated with lumbar myelomeningocele in >95% of cases and syringohydromyelia. In addition it is associated with the following supratentorial anomalies: * dysgenesis of corpus callosum (80-85%) * obstructive hydrocephalus secondary to closure of myelomeningocele (50-98%) * absence of septum pellucidum (40%) * excessive cortical gyration. It is notably not associated with basilar impression, Cl assimilation and KlippelFeil deformity

Answer 92

4 Answer A: Ossification of patellar ligament DISH is also known as Forestier disease or ankylosing hyperostosis and is an ossifying diathesis with a proliferation of entheses (bony growths at tendon and ligament insertions). DISH principally affects the spine, pelvis and extremities. The differential diagnosis includes: fluorosis, acromegaly, ankylosing spondylitis and intervertebral osteochondrosis. The features are ossification of patellar ligament, heel spurs, whiskering of the iliac crest and flowing ossification of at least four contiguous vertebral bodies

Answer 93

48 Answer D: Tangential to the superior end plate of the superior end vertebra and tangential to the inferior end plate of the inferior end vertebra The Cobb angle is the most commonly used method of measuring the scoliotic curve on an AP view. It divides severity of curvature into seven categories and is used to aid selection of patients for surgical treatment and monitoring results of treatment. The vertebrae used in measurement must be noted and the same vertebrae used in subsequent measurements to allow comparison. The RisserFerguson method, which is used less commonly, is measured as described in answer A. The result is not comparable with the Cobb angle.

Answer 94

59 Answer B: Narrowing of the disc space with high signal in the adjacent vertebral bodies on T2-weighted images Early diagnosis is crucial in the management of infective spondylitis. Staphylococcus aureus is the most common pathogen. Imaging abnormalities on X-rays are often subtle and detected late in the disease. MR findings are characteristic and consist of reduced disc space and low signal on Ti and high signal on T2 in the adjacent vertebral bodies (reflecting increased extracellular fluid in the bone marrow). Subligamentous or epidural soft-tissue masses maybe seen.

Answer 95

60 Answer D: Neurogenic cyst The description above describes a chronic process resulting in bone remodelling and atrophy of the cord. Thus an epidural abscess and haematoma are unlikely. This mass is extramedullary but intradural. Although meningiomas and neuromas are intradural they are isointense on Ti hence the best answer is a neurogenic cyst. Neurogenic cyst is an intradural mass, which is commonly seen within the cervical and thoracic region. They are associated with other spinal abnormalities such as diastematomyelia and Klippel-Feil syndrome.

Answer 96

61 Answer B: Tuberculosis Tuberculous spondylitis commonly occurs with an insidious onset in the thoracolumbar region with contiguous involvement of multiple vertebrae. Spread is usually via the haematogenous route and the vertebral bodies are involved more commonly than the posterior elements. Destruction of the vertebral body leads to vertebra plana in children and gibbus deformity in adults. Pyogenic spondylitis is the major differential which occurs more rapidly with destruction, little new bone formation and usually sparing of the posterior elements. In brucellosis, lower lumbar involvement is common and bone destruction is associated with sclerosis. Epidural extension is minimal.

Answer 97

62 Answer C: Residual disc material Appearances of the post-operative spine can be challenging. In the early postoperative period, persistent symptoms are usually due to epidural haematoma, retained fragment or recurrent disc. In the subacute and chronic stage the differential is mainly between a disc and epidural fibrosis. Osseous abnormalities depend on the specific surgical procedure. Epidural fibrosis occurs commonly, enhances with contrast administration and the degree of enhancement varies with time since the operation, enhancing most strongly within a year following surgery. Neuritis, identified as intrathecal enhancement of nerve roots, is seen in approximately 20% of symptomatic patients. Early postoperative root enhancement is common in asymptomatic patients and is considered significant only if it persists beyond at least six to eight months.

Answer 98

63 Answer A: Haemangioma Vertebral haemangiomas are commonly incidental findings. Pain may occur and these become symptomatic if pathologic compression fracture or haemorrhage occurs. Plain X-rays demonstrate trabecular thickening and vertical striations while a `polka dot' appearance is seen on CT On MRI the signal may be variable, although they are usually high on Ti and T2. The major differential on MRI is focal fatty replacement of the marrow and the distinction may be made with fat suppressed sequences. Osteoid osteoma, osteoblastoma and ABC all involve the posterior elements

Answer 99

64 Answer C: MRI brain The MRI and flexion lumbar spine films confirm that the spondylolisthesis is stable and not impinging on the nerve roots. There are now two episodes of neurology affecting different parts of the body, spaced in time, and so this patient may have multiple sclerosis. The next best test is an MRI of the brain.

Answer 100

65 Answer C: Paravertebral ossification A short neck, reduced cervical movement and low posterior hair line are typical findings in Klippel- Feil syndrome, which usually affects the upper cervical region with fusion of vertebral bodies and posterior column. Other features are scoliosis, hemivertebrae, atlantoaxial fusion, rib fusion and ear abnormalities. Sprengel's deformity is often seen with this condition in 25 % of cases and results in rotation and elevation of the scapula due to an omovertebral connection.

Answer 101

66 Answer B: Diffuse idiopathic skeletal hyperostosis DISH is characterised by diffuse flowing ossification at the site of ligamentous and tendinous insertion points. Patients are normally over 50 and it is more common in men. Pain, tenderness and restricted movement are all common complaints. It most commonly affects the mid and lower thoracic regions and extends over at least four contiguous vertebral bodies. The pelvis can be affected with ossification of iliolumbar & sacrotuberous ligaments.

Answer 102

67 Answer D: Spinal dural arteriovenous fistula There are four types of spinal AVM: spinal dural arteriovenous fistula (Type 1), spinal cord AVM (Type 2 and 3) and spinal cord AV fistulas (Type 4). Spinal AVMs present either with progressive sensory and motor loss or acutely following a sudden bleed which has a significant mortality. Haemosiderin may be seen in the subarachnoid spaces reflecting previous bleeds. Spinal AVMs may acutely thrombose and high signal within the cord is very common. Spinal cord arteriovenous malformations are intramedullary while spinal dural and spinal cord arteriovenous malformations are extramed but intradural. Treatment options are embolisation, surgery or both.

Answer 103

5. (a) An enhancing epidural tissue at L4/5 compressing on left L4 nerve root Scar tissue seen after previous disc resection shows enhancement with gadolinium, while a recurrent or sequestrated disc is unlikely to.

Answer 104

Answer: (a) Correct (b) Not correct (c) Correct (d) Not correct (e) Not correct Explanation: Diffuse paraspinal mass is not helpful in differentiating between metastatic and osteoporotic collapse. However focal paraspinal mass is seen more frequently with metastatic collapse. Low signal intensity band on T1WI and T2WI is more common in osteoporotic collapse (93%) than in metastatic collapse (44%). Spared normal marrow signal in a vertebral body is highly suggestive of osteoporotic collapse.

Answer 105

Answers: (a) Correct (b) Correct (c) Not correct (d) Correct (e) Not correct Explanation: Laceration of the dura is not associated with lumbar spine fracture. It is more common in patients with a burst fracture that is associated with neurological deficit and laminae fracture. The epiphyseal plate injuries are rarely encountered in non-accidental trauma.

Answer 106

Answers: (a) Not correct (b) Correct (c) Correct (d) Not correct (e) Not correct Explanation: For the erect lateral view the central beam is directed to the centre of C4. A swimmer’s view is used for better visualization of C7/C8/T1. Hangman’s fracture is secondary to hyperextension resulting in bilateral fractures of pedicles of C2. It is unstable injury and accounts for 4-7% of all spinal fractures.

Answer 107

Answers: (a) Not correct (b) Not correct (c) Not correct (d) Correct (e) Correct Explanation: Diffuse idiopathic skeletal hyperostosis is a common condition characterised by bone proliferation at sites of tendinous and ligamentous insertion of the spine affecting elderly individuals.It commonly affects the elderly more than 50years of age with a slight male predominance. It most commonly involves the lower thoracic spine. Sacroiliac joints are not involved. However, the appearance of spine may be similar to ankylosing spondylitis.

Answer 108

Answers: (a) Not correct (b) Correct (c) Not correct (d) Not correct (e) Not correct Explanation: Vertebral artery injury is usually due to stretching and occurs most frequently at the C1-C2 level. Vertebral artery injuries are more common than carotid artery injuries in blunt neck trauma. Dissection of the extracranial carotid artery is asymptomatic at presentation in 50% of the cases. Diagnosis may be delayed.

Answer 109

Answers: (a) Correct (b) Correct (c) Correct (d) Correct (e) Correct Explanation: Klippel Feil syndrome is also associated with syringomyelia, platybasia, clubfoot, hemivertebrae and congenitally heart diseases. Vertebral fusion may involve the craniovertebral junction and cervicothoracic junctions.

Answer 110

Answers: (a) Not correct (b) Correct (c) Correct (d) Correct (e) Correct Explanation: Flexion teardrop fractures involve avulsion of the anterior inferior corner, usually of the C2 vertebral body with displacement of the involved vertebral body into the spinal column. There is destruction of all soft tissue structures with an associated acute anterior cervical cord syndrome.

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