Spine Flashcards
Klippel-Feil syndrome
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.
Tokuhashi - scoring system for the preoperative evaluation of a patient’s prognosis with a metastatic spinal tumor
6 items considered to affect the outcome
- General condition
- Number of bone metastases other than spinal metastases
- Number of spinal metastases
- Type of the primary lesion
- Presence or absence of metastases to major organs
- State of paralysis
Spondylolisthesis
- 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
Spondylolisthesis
-
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)
Scoliosis
- Idiopathic
- Congenital
- Neuromuscular
- Others -
- Syndromic - Marfans , ED syndrome ,
- NF
- Tumors
- Trauma
- Compensatory
- Complicatons
Functional spinal unit (FSU) smallest physiological unit of the spine that exhibits biomechanical properties similar to that of the entire spine
- 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.
Spinal stability
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
Factors Related to Progression of Adolescent Idiopathic Scoliosis
- Girls > boys
- Premenarchal
- Risser sign of 0
- Double curves > single curves
- Thoracic curves > lumbar curves
- More severe curves
Five major considerations in the natural history of untreated adolescent idiopathic scoliosis in adults
- back pain
- pulmonary function
- psychosocial effects
- mortality
- curve progression
The Risser sign
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
PHV
- 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
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
In boys it is in the early stages of ossification when puberty begins.
Curve Progression
- curve magnitude before skeletal maturity > 25° before skeletal maturity will continue to progress after skeletal maturity
- > 50° thoracic curve will progress 1-2° / year >
- 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
King-Moe Classification five part classification to describe thoracic curve patterns and help guide surgeons implanting Harrington instrumentation
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
Measurement of Curves
three steps
- locating the superior end vertebra
- locating the inferior end vertebra
- drawing intersecting perpendicular lines from the superior surface of the superior end vertebra and from the inferior surface of the inferior end vertebra.
- The end vertebra of the curve is the one that tilts the most into the concavity of the curve being measured
Terminology DISC
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
Lee Zones
- 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.
