Scoliosis - Quiz 2, Part 4

Question 1

2 factors that characterize scoliosis

Answer 1

1. Lateral curvature of spine

2. Vertebral rotation of spine

Question 2

2 factors that determine the severity of scoliosis and need for tx

Answer 2

1. extent of the spinal curvature

2. angle of trunk rotation

Question 3

What is the name of the screening test used to detect scoliosis?

Answer 3

Adam’s forward bend test

Question 4

The extent and severity of the scoliosis curve is calculated using the _________

Answer 4

Cobb angle

Question 5

Type of scoliosis in which the spine not only curves from side to side but the vertebrae also rotate, twisting the spine. As it twists, one side of the rib cage is pushed outward so that the spaces b/t the ribs widen and the shoulder blade protrudes (hump)

Answer 5

Structural scoliosis

Question 6

Type of scoliosis which involves a simple side-to-side curve that does not twist

Answer 6

nonstructural scoliosis

Question 7

Most common form of scoliosis

Answer 7

Idiopathic scoliosis

Question 8

What criteria indicate that scoliosis curves should be treated?

Answer 8

curves >25*
curves that progress >10* while being observed

(curves <20* are usually observed)

Question 9

3 factors that lead to progression of a curve

Answer 9

1. size of curve
2. area of spine involved
3. physiologic age of child

Question 10

mainstay of non-operative tx of significant curves

Answer 10

bracing

Question 11

Appropriate time for surgery is based on which 2 factors?

Answer 11

1. scoliosis curve itself
   - 30-40* –> surgery
2. Vital Capacity of the pt
   - VC 35-40%
   - VC < 20% = surgery is too risky

Question 12

4 approaches to the scoliosis correction procedure

Answer 12

1. posterior approach
2. anterior approach
3. anterograde-posterior approach
4. VATS

Question 13

4 contraindications for VATS for scoliosis

Answer 13

1. inability to tolerate single-lung ventilation
2. severe or acute resp insufficiency
3. high airway pressures w PPV
4. Emphysema

Question 14

A serious scoliosis curve impairs cardio-resp fx causing:

Answer 14

1. R-sided heart failure

2. greater risk of peri-op M&M with death in 60% of pts

Question 15

Curves >___ degrees leads to compromised resp fx

Answer 15

> 65*

Vital capacity is decreased <60% of predicted
insp capacity is most severely affected

Question 16

What is the progression of the resp s/e of serious scoliosis

Answer 16

1. initially dyspnea on exertion, then
2. increased WOB and alv hypovent
3. chronic hypoxia, chronic hypercarbia, increased risk for PHTN and resp fail
4. abnorm ventilatory response to CO2; depend on hypoxic pulm drive to breathe

Question 17

Pre-op predictors of resp insufficiency and need for prolonged intub and resp care post-op

Answer 17

• FVC < 40-50% predicted
• FEV1 < 50% predicted
• Max insp pressure < -30 cmH2O
• Max exp pressure <30 cmH2O

Question 18

True or false: posterior spinal fusion pts may lose 40-100% of more of their EBV

Answer 18

True

Myopathic pts may lose 5-10x this amt

Question 19

Techniques used to prevent blood loss during scoliosis surgery

Answer 19

1. positioning
2. autologous transfusion after pre-donation
3. normovolemic hemodilution
4. cell saver
5. induced controlled HoTN
6. Drugs

Question 20

What must a pts hgb be to donate blood for an autologous transfusion?

Answer 20

> or = 11 g/dL

Question 21

moderate hemodilution is defined as:

Answer 21

1. Decrease of Hct b/t 25-30%

OR

2. Max quantity of blood w/d that will produce Hgb to 9 g/dL or increase after hemodilution

Question 22

Despite its lower O2-carrying capability, Hemodiluted blood maintains adequate tissue oxygenation. Why?

Answer 22

decreased blood viscosity allows better tissue perfusion

Question 23

What is the average Hct of savaged blood, and how does it compare to PRBCs?

Answer 23

50-70%

similar to PRBCs

Question 24

main anesthetic factors that contribute to bleeding during scoliosis surgery

Answer 24

increased arterial or venous pressure

Question 25

in controlled deliberate HoTN during surgery, what is the lowest MAP should be allowed to go?

Answer 25

50 mmHg

Question 26

3 advantages to moderate HoTN anesthesia

Answer 26

1. decreased average blood loss
2. decreased need for transfusion
3. shortened average operating time

Question 27

3 drugs that reduce blood loss during scoliosis surgery

Answer 27

1. Desmopression
2. Aminocaproic acid
3. Aprotinin

Question 28

What is the aim of Neuromonitoring in scoliosis?

Answer 28

to diagnose impending damage at a point when it is reversible

Question 29

Are SSEPs and MEPs sensitive to/affected by anesthetic agents?

Answer 29

yes

Question 30

True or false. When being counseled about the wake-up test, a pt should be reassured that no discomfort or distress will occur during the procedure

Answer 30

True

Question 31

What types of neuromonitoring should be used for optimal protection of neurological fx?

Answer 31

Wake-up test, SSEPs, and MEPs together

Question 32

True or false: The combination of SSEPs and MEPs monitoring during scoliosis surgery represents a standard of care and may obviate the need for an inter-op wake-up test.

Answer 32

True

Question 33

3 Risk factors for post-op vision loss (POVL)

Answer 33

1. Intra-op HoTN
2. Anemia
3. Prone positioning

Question 34

most common dx for POVL

Answer 34

ischemic optic neuropathy (ION)

Question 35

True or false: For post-op pain relief after scoliosis surgery, intrathecal and epidural analgesic techniques are superior over parenteral opioids.

Answer 35

True