FRCS: Spine

According to Waddell et al, non-organic signs should be equated with malingering or the presence of a psychological problem. Waddell’s inappropriate/non-organic signs include: pain on axial compression and pelvic rotation, resisted hip flexion, non-dermatomal sensory loss, non-anatomical tenderness to light touch, cogwheel ‘give way’ weakness, straight leg rise (SLR) discrepancy and overreaction. The presence of more than three signs indicates non-organic features; however, the presence of the non-organic signs should not be equated with malingering but should alert the clinician to the need for more comprehensive testing.

An ipsilateral far lateral disc herniation at L5–S1. A paracentral disc herniation at L4–L5 or a far lateral disc herniation at L5–S1 most commonly result in an L5 radiculopathy and therefore weakness of the gluteus medius, resulting in a Trendelenburg gait. A paracentral herniation at L5–S1 most commonly affects the S1 nerve root. A paracentral herniation at L3–L4 and a far lateral herniation at L4–L5 all affect the L4 root.

It originates underneath the anterior longitudinal ligament and can cause destruction of several contiguous levels. Spinal tuberculosis (TB) originates in the metaphysis of the vertebral body and spreads under the anterior longitudinal ligament causing destruction of several contiguous levels and skip lesions in 15% of the cases. The disc spaces are preserved in the early stages of the infection, which differentiates TB of the spine from pyogenic infection. Contrary to a spinal cord injury occurring as a result of meningomyelitis, a cord injury secondary to direct pressure from the TB abscess or the bony sequestra carries a good prognosis.

A space available for the cord (SAC) of less than 14 mm or an ADI of more than 9–10 mm is an indication for spinal stabilization. An atlantoaxial subluxation occurs in 60–80% of cases of rheumatoid arthritis (RA) as the result of pannus formation at the synovial joints between the dens and the ring of C1. An ADI of >3.5 mm on flexion extension is a common finding in RA and indicates instability; however, it is not necessarily an indication for surgery. A SAC <14 mm or an ADI >9–10 mm is associated with an increased risk of neurological injury and usually requires surgical intervention. A Ranawat C1–C2 index is the distance from the centre of the C2 pedicle to a line connecting the anterior and posterior arches of C1. It is the most reproducible measurement of invagination. A C1–C2 index <13 mm indicates basilar invagination. Subaxial subluxation occurs in 20% of cases of RA, a subluxation >4 mm or more than 20% of the body is indicative of cord compression.

Right L5 perineural fibrosis. Gadolinium-enhanced MRI scans are helpful post discectomy in differentiating between recurrence of disc herniation, which does not enhance with gadolinium, and perineural 61 fibrosis, which shows enhancement around the root. A schwannoma enhances with gadolinium although the root would be enlarged. Systemically the patient is well and there is no evidence of fluid collection on scanning to suggest an infective process.

Pain avoidance. Yellow flags are psychological factors shown to be indicative of long-term chronicity and disability which include a negative attitude that back pain is harmful or severely disabling resulting in fear avoidance behaviour and reduced activity levels. There is a tendency to depression, low morale and social withdrawal.

Decompression of the syrinx in patients above the age of 10 years will improve or stabilize the scoliotic curve. Syringomyelia usually results from lesions that partially obstruct cerebrospinal fluid (CSF) flow including craniocervical junction abnormalities (Chiari malformations), spinal cord trauma and tumours. It often presents with central cord syndrome. Light touch, proprioception and vibration sensation are usually preserved. In most patients over the age of ten, surgical treatment of scoliosis is most likely necessary due to a large initial scoliosis curve or curve progression even after syrinx drainage.

Complete spinal cord injury. An intact bulbocavernous reflex indicates that the patient is not in a state of spinal shock and therefore the cord injury can be classified as a complete injury pattern in this scenario.

Complete C5. Spinal cord injury levels are defined by the ASIA classification. Complete injuries are defined as: No voluntary anal contraction with a distal power MRC 0 and 0/2 distal sensory score (absent perianal sensation) with an intact bulbocavernous reflex (patient not in spinal shock). This patient is functional at C5 (deltoid and biceps) and not functional at C6 (wrist extensors) and C7 (wrist flexion and triceps). His last functional level is C5 indicating a C5 neurological level. It is complete as his distal motor and sensory function is absent.

Enlarged intervertebral foramina. Diastematomyelia is a congenital anomaly caused by a bony, cartilaginous or fibrous bar that results in the ‘splitting’ of the spinal cord in a sagittal direction. When the split does not reunite distally, the condition is referred to as diplomyelia. Diastematomyelia can lead to tethering of the cord and may be associated with neurological deficit. An intrapedicular widening is suggestive. An enlarged intervertebral foramina is seen in patients with neurofibroma.

Left lateral foot numbness. A foraminal or extraforaminal/far lateral disc herniation affects the exiting root (in this case L5), whilst a paracentral or posterolateral disc herniation affects the traversing root (S1). An EHL and EDL weakness would be consistent with an L5 compression. Dorsomedial foot and lateral calf numbness would also be the result of an L5 compression.

Infantile scoliosis commonly affects girls and is usually left-sided. Infantile scoliosis occurs between the ages of 2 months and 3 years. It commonly affects boys and is usually left-sided. An MRI scan should be performed in infantile scoliosis to 62 exclude a Chiari, syrinx or cord tethering. The term early onset scoliosis is now widely used and includes infantile, juvenile and any scoliosis that occurs before the age of 10 years.

Tension signs are usually positive. Central stenosis can be congenital or acquired. Acquired stenosis is the more common type occurring usually secondary to degenerative changes owing to enlargement of the osteoarthritic facets resulting in medial encroachment. It can also occur as the result of various disease processes such as Paget’s disease. It is more common in men because their canal diameter is smaller at the L3–L5 levels than that of women. Tension signs are rarely positive. Unlike lateral recess stenosis or a herniated disc, a central stenosis does not commonly result in leg pain in a dermatomal distribution.

A posterior instrumentation should stop at the distal most tilted vertebra. Scheuermann’s kyphosis is a kyphotic deformity of >45
in the thoracic spine with >5
anterior wedging across three consecutive vertebrae. The condition is often associated with a lumbar hyperlordosis. A mild scoliosis can sometimes be present. It is differentiated from postural kyphosis by the rigidity of the curve. It is the most common cause of thoracic back pain in older children and adolescents. An MRI scan is indicated to look for disc herniation, cord abnormalities and spinal stenosis. Surgery is indicated for curves >80
in skeletally mature patients, it entails a posterior spinal fusion with dual-rod instrumentation þ/ anterior release and interbody fusion. The fusion level should stop distally at the vertebra which is parallel to the floor (usually the L3 level). A ligamentum flavum excision should be performed at the apex to prevent buckling of the ligament and therefore decrease the risk of neurological deficit.

With age, the proteoglycan (PG) synthesis decreases; however, the PG concentration increases due to the drop in the water content. The intervertebral disc is made up of the annulus fibrosis and nucleus pulposus. The annulus is rich in collage type I and resists tensile forces; the nucleus is rich in type II collagen and resists compressive forces. Age-related changes include:  A decrease in proteoglycan synthesis resulting in an overall decrease in the proteoglycan concentration despite a drop in the water content.  Chondroitin sulphate concentration decreases.  The absolute quantity of collagen remains constant (there is a decrease in type I and increase in type III collagen).

The mechanism of injury is a primary hyperflexion of the neck. A hangman’s fracture is a traumatic spondylolisthesis of C2 on C3 as a result of bilateral fracture of C2 pars or pedicles. The mechanism of injury is an extension injury (causes pars fracture) with a secondary flexion (disrupts the posterior longitudinal ligament (PLL) and the disc) resulting in the anterolisthesis. In 30% there is a concomitant C-spine fracture. There is usually no neurological deficit except in type III. Levine and Edwards have classified this fracture as follows: Type I – minimal displacement and angulation with an intact disc. Treatment: Philadelphia-like collar. Type II – displaced fracture of the pars with >3 mm displacement and significant angulation (disc and PLL disrupted). Reduce with traction then apply halo for 2 months. 63 Type IIA – no horizontal displacement but significant angulation. Reduction with hyperextension WITHOUT TRACTION then apply halo for 2 months. Type III – is associated with bilateral facet dislocation and requires an open reduction of the dislocation with C2/C3 fusion.

A ligamentous chance fracture should be treated using a compression construct with one level above and one level below the fracture. A chance fracture is the result of a flexion-distraction injury (seatbelt injury). It can be bony, ligamentous or mixed. Gastrointestinal injuries occur in 50% of cases. The bony lesions unite non–operatively with a brace in extension. The ligamentous type may remain unstable and therefore should be treated operatively using a compression construct (restore the tension band) with one level above and one level below the fracture. A chance fracture is seldom associated with a neurological deficit unless translation occurs.

Flexion/extension of the C-spine is often reduced. Contrary to the common belief, the classic triad of low posterior hairline, short neck and reduced range of movement is seen in fewer than 50% of patients with Klippel–Feil syndrome. A Sprengel deformity is seen in 33% of cases, congenital scoliosis occurs in 60% and renal abnormalities is encountered in 33% of cases. Lateral side bending is usually limited whilst flexion/extension is often preserved.

A disc and the vertebrae above and below, including their interlocking facet joints. A spinal motion segment is made up of a disc with its adjacent vertebrae and their interlocking facet joints devoid of musculature.

Helical CT scan with a 2–3 mm slice from the base of the skull to at least T1. If it is anticipated that a patient will remain unconscious, unassessable or unreliable for clinical examination for more than 48 hours, radiological spinal clearance imaging should be undertaken. For the cervical spine, the appropriate standard is a thin-slice (2–3 mm) helical CT scan from the base of the skull to at least T1 with both sagittal and coronal reconstructions. This scan can demonstrate the subtle abnormalities offering high sensitivity and specificity in detecting unstable injuries of the cervical spine. Plain radiographs are insensitive in the neck and the upper thoracic spine. MRI scanning has high sensitivity but only moderate specificity and is logistically difficult for ITU patients.

Medical management with non-steroidal anti-inflammatory drugs (NSAIDs) is a satisfactory treatment modality in this case. Bone scan is almost invariably positive in osteoid osteoma. The natural history of osteoid osteoma is for spontaneous resolution in 6–7 years so medical management with non-steroidal anti-inflammatory drugs (NSAIDs) is an option for some patients. As scoliosis resolves with resection/ablation in a child under 11 years of age, an operative intervention should be undertaken in this case.

Anterior cervical decompression and fusion. This patient has myelopathic changes within the cord probably as a result of an anterior degenerative disc. The presence of a fixed kyphosis of >10
is a contraindication to a 64 posterior decompression þ/ fusion. In addition, posterior procedures are ineffective in this case as the anterior compression on the cord will remain. The anterior approach provides direct access to the disc herniation and provides immediate and long-term stability to the motion segment.

Recurrent laryngeal nerve injury risk is lower at the lower C-spine levels (C6–C7). The injury risk of the recurrent laryngeal nerve is higher at the lower C-spine (C6–C7) as it initially descends into the thorax within the carotid sheath, then it curves around the aortic arch and ascends back into the neck running between the trachea and oesophagus to supply the larynx. The nerves are usually safe as long as the retractors are placed underneath the longus colli muscles.

A type II rotator subluxation indicates an insufficiency of the transverse and alar ligaments. Atlantoaxial rotatory instability can occur after trauma or spontaneously. It is associated with Morquio syndrome, spondyloepiphyseal dysplasia, Larsen’s syndrome, achondroplasia and Grisel’s syndrome. It is present in 25% of children with Down syndrome. In type I, the odontoid acts as a pivot point and there is no anterior subluxation. In type II, one facet acts as a pivot with an ADI 3–5 mm. The transverse ligament is insufficient. In type III, the alar and transverse ligaments are incompetent resulting in bilateral facet subluxation with an ADI >5 mm.

A hyperextension injury in a patient with a facet joint hypertrophy and thickened ligamentum flavum. Central cord syndrome is the most common incomplete spinal cord lesion. It is usually seen in patients with cervical spondylosis who sustain a hyperextension injury. The mechanism causes compression of the cord by osteophytes anteriorly and ligamentum flavum posteriorly. 65 1. If surgery for intracapsular fracture fixation is not carried out within 12 hours, avascular necrosis (AVN) and non-union rates are affected in this way? a. No difference between AVN and non-union rates. b. AVN higher, no change in non-union. c. No change in AVN, non-union higher. d. AVN and non-union both higher. e. AVN higher but non-union lower. 2. Injury to which artery is most likely to cause uncontrollable bleeding during the posterior approach to the hip? a. Inferior gluteal. b. Superior gluteal. c. Pudendal. d. Ascending branch of lateral circumflex femoral. e. Popliteal. 3. With regard to closed suction drains used in surgery, which of the following is true? a. Wound infection is higher with use of drains. b. Haematoma formation is lower with use of drains. c. Wound dehiscence is more likely without the use of drains. d. Blood transfusion is more likely with the use of drains. e. Bruising is more likely with the use of drains. 4. What is the predominant source of femoral head perfusion? a. Lateral circumflex artery. b. Obturator artery. c. Medial circumflex artery. d. Descending branch of lateral circumflex artery. e. Superior gluteal artery. 5. The main internal rotators of the hip are? a. Gluteus minimus and tensor fascia lata. b. Obturator internus, superior and inferior gemelli. # Cambridge University Press 2012. 71