AMIS® – Anterior Minimally Invasive Surgery

A Milestone for KPJ Tawakkal Specialist Hospital, Kuala Lumpur, MALAYSIA; it registers another first in Minimally Invasive Technique used in Total Hip Replacement Surgery

KPJ Tawakkal Specialist Hospital, Kuala Lumpur was in the news recently for introducing the latest in minimally invasive surgery for total hip replacement called AMIS® which stands for Anterior Minimal Invasive Surgery for Total Hip Replacement. Currently there are few techniques for Total Hip Replacement (THR) and the most commonly used are posterior and lateral approaches. However, in the last 5 years, increasing number of surgeons are changing to an alternate anterior approach. This direct anterior approach utilises a muscle interval in front of the hip joint in which muscles and tendons are not cut for exposure of the joint and to perform the surgery. In US, the last 5 years the number of THR performed using this new approach has increased to more than 30%. InfoMed was given the opportunity to discuss and interview Dr. G. Ruslan Nazaruddin Simanjuntak, Consultant Orthopaedic Surgeon at KPJ Tawakkal who performed this procedure for the first time in Malaysia. The interesting insight into this new procedure by Dr. Ruslan is given below.

This new approach using the intermuscular space for the surgeon to gain access to the hip has the primary goal of minimising harm to the muscles, blood vessels, tendons and nerves surrounding the joint. The possible muscle release is reduced to a minimum and is an ideal approach for a traumatic surgery which is fundamental for a fast recovery.
For the surgery, the patient lies in the supine position. The incision is anterior to the hip joint. It opens gradually through anterior to the tensor fascia lata and deeper into the capsule in between the muscle. The capsule then is cut accordingly. The procedure is performed in the hospitals.

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The AIMS® procedure is eligible for patients who do not have much bone defect, for patients who are diagnosed with primary osteoarthritis and for those who are non-osteoporotic.

AMIS Potential Benefits

  • Smaller skin scar – the skin incision is often shorter than the current conventional surgery.
  • Reduce blood loss – since no muscles are cut, it potentially reduces blood loss and transfusions are rare as well as potential blood clots (deep venous thrombosis) is less likely.
  • Decreases the post-operative pain – again due to the technique used where no muscles are cut.
  • Shorter hospitalisation – the potential to reduce the duration of the hospital stay is good, as the approach does not cut the muscles, fundamental for fast recovery.
  • Faster rehabilitation – enables the patient to return to daily activities quicker.
  • Reduces the risk of dislocation – the preservation of muscles significantly improves the stability of the hip and thus minimises the risk of dislocation and post-operative limitation of movements.
  • Prevents limping – the surgical technique which minimises muscle and nerve damage,, thus reduces the chances of limping.
  • Decreases the incidence of complications – is the sum of all the above potential benefits as compared to the conventional techniques.

Interview with Dr. Ruslan Nazaruddin Simanjuntak Consultant Orthopaedic Surgeon at KPJ Tawakkal Specialist Hospital, MALAYSIA

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1. How long has this surgery been performed overseas?

There has been different type of anterior approach, but this AMIS® was started about 5 to 6 years ago in Paris. It has spread very fast in Europe. This procedure was done for the first time by Dr. Frederic Laude from France including the development of new surgical instrumentation and advancement new operating table. In Australia, it was introduced about 3 years ago and almost 15 to 20% of the THR surgeries in Australia are done using this technique. One of the surgeons I learned this technique is from Perth and he has in the last three years done almost 1,000 such surgeries.

2. Why is this better approach?

Cosmetically this procedure is better. We can use bikini line incision with this approach. And since it does not cut the muscle and nerves, it will cost less pain and the recovery is much faster.

3. Where and when did you learn this new technique?

I learnt the theory on this procedure in Switzerland, and continued the practical part in Perth, Australia which included cadaveric workshop and live surgeries. Following the guidelines, for me to introduce this procedure here in Malaysia, I was required to do the surgery under the supervision of a surgeon who has mastered this skill to ensure proper technique is used as in the AMIS® procedure. I also had the opportunity to meet Dr. Frederic Laude during a conference in Australia last year where he was the main speaker. I have discussion in depth about this technique with him.

Officially I have done my first AMIS® in March 2015 under supervision and am certified to do this surgery and also certified to teach as well.

4. In terms of outcome, how safe is the surgery and what about any complications?

It is safe, provided you know the technique. For this reason, the part of the requirement before your start performing this surgery is to learn from the expert surgeons who are doing this surgery. The expert will assist me in the surgery and after perfecting the skills, you are allowed to do it on your own. This will allow the surgeon to do it in correct technique.

5. Do you need special equipment to perform this surgery?

Yes, we need a special table to manoeuvre the leg and the retractor and special drilling instrument.

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6. What are the risks in MIS surgeries and does AIMS® reduces any of these risks?

There are 2 incision techniques introduced about ten to twelve years ago in the US, which traumatises the muscle a lot. The risk is basically in the malposition of the implant and cup and in cutting the muscle and nerves. However, this AIMS® technique will reduce all these complication.

7. How is the recovery?

It is faster than the usual minimally invasive total hip replacement surgery.

8. Who would be the candidates for AIMS®?

Most of patients for THR would be eligible for this procedure except those above 75 years old and having fragile bones. It is suitable for those with osteoarthritis.
In terms of costs, it would be more expensive because of the special instruments and implants used. The important aspect is the shorter surgical time, much faster recovery and rehabilitation and better outcomes.

9. Any plans to introduce this procedure in other KPJ Hospitals in the future?

I hope to introduce this technique to the rest of the KPJ hospitals and other hospitals too. I will try to make a presentation in our next KPJ conference in August 2015. For the first time, recently I was glad to assist a surgeon in Kota Baru Hospital, Kelantan to perform this surgery.

10. What skills set should an orthopaedic surgeon possess to take on this procedure successfully?

First they should know how to do the conventional technique. This technique is totally different and the surgeon got to learn this technique under supervision.

11. Are you now engaged in teaching this procedure in other hospitals in Malaysia and the region?

Currently in KPJ hospitals, other than KPJ Tawakkal Specialist Hospitals, KPJ Selangor Hospital has started doing this procedure. I have also done with the surgeon the procedure at Hospital Kota Baru Hospital, Kelantan recently.