Entrance Exam

Question 1

Describe the EPIC messaging for an OLIF 25 approach.

Answer 1

E - Evolution in lateral access (moving away from the nerves)
P- Psoas preserving (retractor outside of the muscle)
I- iliac crest avoidance (incision is in front of the iliac crest)
C- complete procedure solution (integration of all technology)

Question 2

The ______________ is a large tubular nerve within the psoas that can become compressed up against the transverse process during a trans-psoas approach.

Answer 2

Femoral nerve

Question 3

The _____________ is a sensory nerve that may be seen on the anterior side of the psoas muscle.

Answer 3

Genitofemoral nerve

Question 4

In an OLIF procedure, where does the surgeon typically stand in relation to the patient?

Answer 4

Anterior or belly to belly

Question 5

In a trans-psoas approach, what nerve root plexus is at risk while accessing the disc space?

Answer 5

L4/L5 (L4 Nerve)

Question 6

For an OLIF procedure, where is the appropriate location for the break in the table to occur in relation to the patient’s anatomy?

Answer 6

There is no need to break the table

Question 7

In which direction does the aorta and inferior vena cava move when the patient is placed in the right lateral decubitus position?

Answer 7

They both move anterior, down, and away to open the oblique corridor

Question 8

What should you look for in a proper A/P C-arm image?

Answer 8

Crisp endplates, spinous process in the center and pedicles at the top of the body

Question 9

What should you look for in a proper lateral C-arm image?

Answer 9

Crisp endplates and pedicles superimposed

Question 10

Why is the OLIF25 procedure recommended to be performed from the patients left side (right lateral decubitus position on table)?

Answer 10

Because the aorta is on the left side and has less chance of vascular injury. The aorta has more of a muscular texture.

Question 11

During the oblique lateral procedure, what is the maneuver called that allows the surgeon to align the instruments in the appropriate position from L2 to L5?

Answer 11

Orthogonal maneuver

Question 12

What levels are 0LIF25 and OLIF51 indicated to access all together?

Answer 12

L2 to S1

Question 13

Where is the surgeon positioned during an OLIF25 procedure?

Answer 13

Anterior or belly to belly

Question 14

When using neuromonitoring, why can’t the genitofemoral nerve be detected using a standard lumbar electrode montage?

Answer 14

Because it is a sensory nerve. It can only be monitored in males and only by placing the needles in the cremaster muscles (not likely).

Question 15

When making the incision for the OLIF51 procedure, the dissection is made through which muscle?

Answer 15

Either the external oblique muscle or aponeurosis and fascia.

Question 16

During any lateral procedure, why must the contralateral annulus be released using a cobb?

Answer 16

This will release and allow both the implant and the trial to go fully across the apophyseal ring and restore height.

Question 17

In a trans-psoas approach, if the surgeon is accessing the disk space using the X-Pak probe and a response is generated, to which direction should the surgeon make an adjustment?

Answer 17

Anteriorly

Question 18

Where is the femoral nerve in relationship to the L4-L5 disc?

Answer 18

Usually seen at the 50 yard line or posterior. However it has been seen as far forward as the 25 yard line (or zone 2)

Question 19

The move from LLIF to 0LIF25 can be compared to what historical procedural change?

Answer 19

PLIF to TLIF

Question 20

During the LLIF and OLIF access, the surgeon will work his/her way through the external and internal obliques, then the transversus abdominus/transversalis. Afterwards, he/she should see a yellow substance. What is it and where should he/she now be?

Answer 20

Retroperitoneal space and retroperitoneal fat

Question 21

Where does the bifurcation of the aorta and vena cava typically begin?

Answer 21

Typically this begins at L4

Question 22

What does ante-psoas refer to?

Answer 22

Ante - in front of
Psoas- the muscle

= In front of the psoas muscle

Question 23

Name the four main causes of neural injury in a lateral approach:

Answer 23

Spear/sever
Squeeze
Retraction for too long on the transverse process
Stretching-Displacing

Question 24

In which direction do abdominal structures such as the peritoneum move when the patient is placed in a lateral position?

Answer 24

Down and away from the spine, gravity pulls everything out of the way

Question 25

Describe the W I N messaging for the OLIF51 approach:

Answer 25

W- Weight falls forward (abdominal content falls forward)
I- Incision outside of the rectus muscle (less dissection vs. ALIF)
N- No patient repositioning (L2-S1 access to the disc space)

Question 26

What landmarks should the surgeon mark out when performing an OLIF25 procedure?

Answer 26

Mark disc angles in vertebral bodies. Mark 4-10cm anterior from midline of disc space for incision

Question 27

What traditional procedure incision is the OLIF51 incision modeled after?

Answer 27

This is the similar approach to the McBurney and McArthur appendectomy incision. Incision used in the appendectomies since 1894. Make 1.5-5cm incision parallel to the ASIS.

Question 28

What pre-op image is most important in an OLIF procedure?

Answer 28

MRI (for vascular structures)

Question 29

What are the indications for Infuse in the OLIF25 and OLIF51 procedures?

Answer 29

Only one-level clearance. Only with Clydesdale PEEK
Only in ante-approach
Perimeter at 5/1

Question 30

The _________ is attached by a membrane to the peritoneum and falls forward with the peritoneum during a retro-peritoneal approach.

Answer 30

Ureter

Question 31

What is transitional anatomy? If observed during an OLIF procedure, how should a surgeon proceed?

Answer 31

Ilio-lumbar vein. They should visualize the vascular anatomy.

Question 32

Describe the differences in set-up for an OLIF procedure versus a DLIF procedure?

Answer 32

The surgeon stands belly to belly or anterior to the patient. And the incision is more anterior.

Question 33

List the interbody and fixation options for an OLIF25 procedure:

Answer 33

Clydesdale with bilateral screws
Clydesdale PTC with bilateral screws
Pivox with lateral screws only
Pivox with bilateral screws

Question 34

List the interbody and fixation options for an OLIF51 procedure:

Answer 34

Perimeter with plate. Perimeter with posterior screws.
Divergence with plate.
Divergence with posterior fixation. Precision graft with posterior fixation.

Question 35

Describe pelvic incidence:

Answer 35

90° off the mid sacrum, angle from the midpoint of femoral heads. Typically 40° to 65°

Question 36

What two main pelvic parameters make up a patient’s pelvic incidence?

Answer 36

Lumbar lordosis.

Pelvic incidence.

Question 37

In an 0LIF51 procedure, describe the order in which the retractor blades should be positioned for the approach.

Answer 37

The dark blue retractor should go under the iliac vein after the adventitial layer has been released. This step secures protection and lateralization of the left common iliac vein and artery. The green Hohmann blade sweeps medially and wraps around the contralateral side of the disk space. The light blue blades are placed on L5 to protect the bifurcation.

Question 38

In an 0LIF51 procedure, describe the order in which the retractor blades should be removed.

Answer 38

Cephalad light blue blade first, then the lateral dark blue blade, and finally the medial green blade

Question 39

Where is the sympathetic chain (SC) located anatomically in the lumbar spine?

Answer 39

On the lateral aspect of the spine