AMISsurgical technique

tips and tricks

SD Koutsostathis

MISDefinition

Minimally Invasive Surgery

NOT

Mini Incision Surgery

Training

Learning center

Visit reference centers

Cadaver labs

Expert assistance

Requirements in new techniques

Pre-op planning

Installation

Traction table. Correct positioning

Installation

Anatomic landmarks

Anterior Minimally Invasive Surgery

Rectus femoris

DB LCFA

Approach

Calcar

Iliocapsularis

Gluteus minimus

Break posterior

cortex

RECTUS FEMORIS

CAPSULE

I-I line (depth)Orientation

Parallel to TAL

GT Calcar

Pyriformis

Planning of head-neck length is possible

FAST CLOSURE

?• Is it an evolution?

• Is it safe?

• Is it better for the patient?

OR

• Commercial trick?

• Industry promoted technique?

• Role of media – internet?

different

benefit

profile

different

risks

different

intervals

different

approaches

!!

AMIS® technique - Advantages

• Shorter stays in the hospital.

• Shorter rehabilitation.

• Reduced risk of dislocation.

• Immediate post-operative muscle

tone preservation.

• Decreased post-operative pain.

• Less blood loss.

• Faster return to daily activities.

• Reduction of scar tissues.

Direct Anterior THA

What are the Concerns?

• Exposure

• Equipment and

Resources

• Learning Curve

• Complications

What are the early problems with

Direct Anterior Approach to Hip

• Operative time

• Fluoro exposure

• Blood loss

• Wound complications

• Femur fracture

• Lat. Fem Cutaneous N. Damage

• Ascending branch of the lateral femoral circumflex artery Injury

Is AMIS better than direct lateral ?

• Less muscle damage

Muller et al, Arch Orthop Trauma Surg, Feb 2011

•Better gait symmetry

Lugade et al, Clin Biomech, Aug 2010

•Better SF-36 and WOMAC at 1 yr

Restrepo, et al, JOA, Aug 2010

Is it better than posterior ?

Limited comparative data at this time

Several ongoing prospective randomized studies

Retrospective comparison study of 45 patients who

had DAA on one hip and posterior or lateral approach

on other hip

Shorter LOS with DAA (2.27 vs 3.87 days)

Less PCA usage (11.6 vs 24.6 mg) morphine

Better ambulation POD #1 166 feet vs 49 feet

Gorab, et al, AAOS 2011

Is it better than posterior ?

LEARNING CURVE COMPLICATIONS

?

Recognize or avoid

the LFCN!!

Good preperation of the entry point

femoral nerve palsies

varus positioning of the stem

Suggestions to avoid problems

Check your reaming depth using fluoro

Insert the acetabular prosthesis carefully under fluoro

acetabular implant protrusio

Suggestions to avoid problems

Accurate and complete femoral neck osteotomy

Careful femoral canal preparation and broaching

fracture of the greater trochanter

Suggestions to avoid problems

periprosthetic fracture

• Identify the femoral canal and be careful when broaching

• In the beginning you can use fluoro

Suggestions to avoid problems

When do complications happen??

0

1

2

3

4

5

0 50 100 150 200 250 300

minor

major

Cases

We suggest that:

There is a learning curve of at least 50

cases for an experienced hip surgeon

Hands on training is necessary

Expect complications but do your best to decrease

their frequency!!

Conclusion

Literature is available to support use of most

surgical approaches

Do not forget the principles of THA

• Long term fixation

• Low wear

Be care about allowing small part (approach)

dictate the whole procedure

5 TIPS for success (5 P’s)

1. Practice

2. Patient Selection

3. Plan

4. Patience

5. Predict Complications

Take home messages

No miracles in approaches!

Learn all of them if you can

Learn mini approaches and use them with caution

Be aware of pitfalls when taking decisions