Spine

Question 1

Klippel-Feil syndrome

Answer 1

Klippel-Feil syndrome is congenital fusion of the cervical vertebrae that may involve

• two segments, a congenital block vertebra, or the entire cervical spine.
• Congenital cervical fusion is a result of the failure of normal segmentation of the cervical somites during the third to eighth week of life
• cardiorespiratory, genitourinary, and auditory systems frequently are involved.

Question 2

Tokuhashi - scoring system for the preoperative evaluation of a patient’s prognosis with a metastatic spinal tumor

Answer 2

6 items considered to affect the outcome

1. General condition
2. Number of bone metastases other than spinal metastases
3. Number of spinal metastases
4. Type of the primary lesion
5. Presence or absence of metastases to major organs
6. State of paralysis

Question 3

Spondylolisthesis

Answer 3

• type I • Dysplastic • Secondary to congenital abnormalities of lumbosacral articulation including misoriented or hypoplastic facets, sacral deficiency, poorly developed pars • Posterior elements are intact (no spondylolysis) • More significant neurologic symptoms
• Type II-A • Isthmic - Pars Fatigue Fx
• Type II-B • Isthmic - Pars Elongation due to healed stress fx
• Type II-C • Isthmic - Pars Acute Fx
• Type III • Degenerative
• Type IV • Traumatic
• Type V • Neoplastic

Question 4

Spondylolisthesis

Answer 4

• pelvic tilt = pelvic incidence - sacral slope
  
  • a line is drawn from the center of the S1 endplate to the center of the femoral head a second vertical line (parallel with side margin of radiograph) line is drawn intersecting the center of the femoral head the angle between these two lines is the pelvic tilt (see angle Z in figure above)
• sacral slope = pelvic incidence - pelvic tilt
  
  • a line is drawn parallel to the S1 enplate a second horizontal line (parallel to the inferior margin of the radiograph) is drawn the angle between these two lines is the sacral slope (see angle Y in the figure above)

Question 5

Scoliosis

Answer 5

• Idiopathic
• Congenital
• Neuromuscular
• Others -
  
  • Syndromic - Marfans , ED syndrome ,
  • NF
  • Tumors
  • Trauma
  • Compensatory
  • Complicatons

Question 6

Functional spinal unit (FSU) smallest physiological unit of the spine that exhibits biomechanical properties similar to that of the entire spine

Answer 6

• The cephalad and caudad vertebral body, as well as the intervertebral disc and the corresponding facet joints function, is to provide physiologic motion and protect neural elements intradiscal pressure depends on the position
• The neutral zone is the motion region of the joint which functions independent of the osseoligamentous complex and a relatively small load produces a large displacement on the load-displacement curve
• elastic zone is the remaining area of the joint, which produces maximum resistance to displacement by a load.

Question 7

Spinal stability

Answer 7

defined when, under physiologic loading, there is neither abnormal strain or excessive motion in the FSU maintained by FSU muscular tension abdominal and thoracic pressure rib cage support

Question 8

Factors Related to Progression of Adolescent Idiopathic Scoliosis

Answer 8

• Girls > boys
• Premenarchal
• Risser sign of 0
• Double curves > single curves
• Thoracic curves > lumbar curves
• More severe curves

Question 9

Five major considerations in the natural history of untreated adolescent idiopathic scoliosis in adults

Answer 9

• back pain
• pulmonary function
• psychosocial effects
• mortality
• curve progression

Question 10

The Risser sign

Answer 10

The Risser sign is a measurement based on the ossification of the iliac apophysis, which is divided into four quadrants. Risser sign proceeds from grade

• 0, no ossification,
• to grade 4, in which all four quadrants of the apophysis have ossification.
• Risser grade 5 is when the apophysis has fused completely to the ilium when the patient is skeletally mature.
• The Risser sign may not be as useful for predicting curve progression because grade 1 has been found to begin after the period of rapid adolescent growth or peak height velocity

Question 11

PHV

Answer 11

• PHV is calculated from serial height measurements and is expressed as centimeters of growth per year.
• Average values of PHV are 8 cm per year in girls 9.5 cm per year in boys

Question 12

The triradiate cartilage begins to ossify in the early stages of puberty. In girls it is completely ossified after the period of PHV and before Risser grade 1 and menarche

Answer 12

In boys it is in the early stages of ossification when puberty begins.

Question 13

Curve Progression

Answer 13

1. curve magnitude before skeletal maturity > 25° before skeletal maturity will continue to progress after skeletal maturity
2. > 50° thoracic curve will progress 1-2° / year >
3. 40° lumbar curve will progress 1-2° / year

• remaining skeletal growth
  
  • younger age < 12 years at presentation
  • Tanner stage (< 3 for females)
  • Risser Stage (0-1)
    
    • Risser 0 covers the first 2/3rd of the pubertal growth spurt correlates with the greatest velocity of skeletal linear growth open triradiate cartilage peak growth velocity is the best predictor of curve progression in females it occurs just before menarche and before
    • Risser 1 (girls usually reach skeletal maturity 1.5 yrs after menarche) most closely correlates with the Tanner-Whitehouse III RUS method of skeletal maturity determination
    • if curve is >30° before peak height velocity there is a strong likelihood of the need for surgery

Question 14

King-Moe Classification five part classification to describe thoracic curve patterns and help guide surgeons implanting Harrington instrumentation

Answer 14

Lenke Classification more comprehensive classification based on PA, lateral, and supine bending films helps to decide upon which curves need to be included within the fusion construct

Question 15

Measurement of Curves

Answer 15

three steps

1. locating the superior end vertebra
2. locating the inferior end vertebra
3. drawing intersecting perpendicular lines from the superior surface of the superior end vertebra and from the inferior surface of the inferior end vertebra.
4. The end vertebra of the curve is the one that tilts the most into the concavity of the curve being measured

Question 16

Curve Patterns Ponseti and Friedman Classification

Answer 16

• Single major lumbar curve.
• Single major thoracolumbar curve.
• Combined thoracic and lumbar curves (double major curves)
• The single major thoracic curve
• Single major high thoracic curve
• Double major thoracic curve

Question 17

King Classification - is used to describe thoracic curves.

Answer 17

1. lumbar curve is larger than the thoracic curve
2. thoracic scoliosis is a combined thoracic and lumbar curve pattern
3. thoracic scoliosis with the lumbar curve not crossing the midline
4. A type IV curve is a single long thoracic curve
5. A type V curve is a double structural thoracic curve

Question 18

Lenke Classification three-step classification system for adolescent idiopathic scoliosis.

Answer 18

The three steps in this classification system are

1. identification of the primary curve
2. assignment of the lumbar modifier -
   
   1. The lumbar spine modifier is then determined by the relationship of the CSVL to the concave pedicle of the apical lumbar vertebra (3)
3. assignment of the thoracic sagittal modifier -
   
   1. The sagittal modifier is hypokyphotic (<10 degrees),
   2. normal (10 to 40 degrees)
   3. hyperkyphotic (>40 degrees).

Question 19

Scoliosis Radiographs

Goals of scoliosis surgery

• Stable pain free spinal stabilisation
• restoration of trunkal balance
• improved cosmesis including rib prominence, shoulder and hip assymetry

Answer 19

• Cobb angle > 10° defined as scoliosis intra-interobserver error of 3-5° spinal balance - coronal balance is determined by alignment of C7 plumb line to central sacral vertical line sagittal balance is based on C7 plumb from center of C7 to the posterior-superior corner of S1
• stable zone - between lines drawn vertically from lumbosacral facet joints stable vertebrae - most proximal vertebrae that is most closely bisected by central sacral vertical line
• neutral vertebrae - rotationally neutral (spinous process equal distance to pedicles on PA x-ray) end vertebrae -
• end vertebra is defined as the vertebra that is most tilted from the horizontal apical vertebra
• apical vertebrae - the apical vertebrae is the most laterally displaced and most horizontally oriented vertebra
• Terminal vertebrae - most tilted vertebra and used to measure cobb angle
• clavicle angle best predictor of postoperative shoulder balance

Question 20

MRI Scolosis

Answer 20

should extend from posterior fossa to conus purpose is to rule out intraspinal anomalies indications to obtain MRI

• atypical curve pattern (left thoracic curve, short angular curve, apical kyphosis)
• rapid progression
• excessive kyphosis
• structural abnormalities
• neurologic symptoms or pain
• foot deformities
• asymmetric abdominal reflexes
• a syrinx is associated with abnormal abdominal reflexes and a curve without significant rotation

Question 21

Neurofibromatosis

Answer 21

For the diagnosis of neurofibromatosis to be made, two of the following features are necessary:

• A minimum of six café au lait spots larger than 1.5 cm in diameter in a postpubertal patient and larger than 5 mm in diameter in prepubertal patients
• Two or more neurofibromas of any type or one plexiform neurofibroma
• Freckling in the inguinal or axillary regions
• Optic glioma Two or more iris Lisch nodules by slit-lamp examination
• A distinctive osseous lesion
• A first-degree relative with a definitive diagnosis of neurofibromatosis

Question 22

Terminology DISC

Answer 22

normal desiccation annular fissure

• Disc bulge: annular tissue projects beyond the margins of the adjacent vertebral bodies, over more than 90 degrees of circumference
• Circumferential bulge: involves the entire disc circumference
• Asymmetric bulge: does not involving the entire circumference, but more than 90 degrees herniation
• protrusion: ​​focal herniation of disc material beyond margins of adjacent vertebral body, over less than 90 degrees of circumference, with a base that is wider than dome
• extrusion: focal herniation of disc nuclear material through an annular defect, remaining in continuity with the disc, with a base narrower than the dome of the extrusion
• sequestration: distal migration of extruded disc material away from the disc, with no direct continuation with the adjacent disc pseudodisc of anterolisthesis: deformity of annular fibres due to anterolisthesis mimicking a true protrusion or bulge

Question 23

Lee Zones

Answer 23

• Central spinal stenosis denotes involvement of the area between the facet joints, which is occupied by the dura and its contents. Stenosis in this region usually is caused by protrusion of a disc, bulging anulus, osteophyte formation, or buckled or thickened ligamentum flavum.
• The lateral recess, also known as “Lee’s entrance zone,” begins at the medial border of the superior articular process and extends to the medial border of the pedicle. This is where the nerve root exits the dura and courses distally and laterally under the superior articular facet
• Lee’s midzone describes the foraminal region, which lies ventral to the pars. Its borders are the lateral recess medially, the posterior vertebral body and disc ventrally, the pars and intertransverse ligament dorsally, and the lateral border of the pedicle laterally.

Question 24

L4 Root Compression

Indicative of L3-4 disc herniation or pathologic condition localized to L4 foramen.

Answer 24

Sensory Deficit

• Posterolateral thigh, anterior knee, and medial leg

Motor Weakness

• Quadriceps (variable)
• Hip adductors (variable)
• Anterior Tibial Weakness

Reflex change

• Patellar tendon
• Anterior tibial tendon (variable)

Question 25

L5 Root Compression \* ## Footnote \* Indicative of L4-5 disc herniation or pathologic condition localized to L5 foramen

Answer 25

**Sensory Deficit** * Anterolateral leg, dorsum of the foot, and great toe **Motor Weakness** * Extensor hallucis longus * Gluteus medius * Extensor digitorum longus and brevis **Reflex Change** * Usually none * Posterior tibial (difficult to elicit)

Question 26

S1 Root Compression \* \* Indicative of L5-S1 disc herniation or pathologic condition localized to the S1 foramen.

Answer 26

**Sensory Deficit** * Lateral malleolus, lateral foot, heel, and web of fourth and fifth toes **Motor Weakness** * Peroneus longus and brevis * Gastrocnemius-soleus complex * Gluteus maximus **Reflex Change** * Achilles tendon (gastrocnemius-soleus complex)

Question 27

Lumbar Discectomy

Answer 27

The discectomy is complete when * the lateral recess is adequately decompressed; * the 90-degree dissection can be probed to the back of the cephalad vertebral body, the disc space, and the back of the caudal vertebral body out to the midline without any protrusions into the canal * the 90-degree dissector can be spun (helicopter maneuver) beneath the traversing nerve root without any restrictions; * the traversing nerve root is freely retractable both medially and laterally.