The IMAS technique – a phase shift in the philosophy of surgery

The IMAS technique – a phase shift in the philosophy of surgery

Consultant spinal orthopaedic surgeon at the Royal London (Barts Health NHS Trust) Syed Aftab, was the first robotic spinal surgeon in the UK. Here he discusses how the IMAS technique (Inter pedicular Micro Access Surgery) helps the surgeon become both controlled and effective

During my training I spent many hours intra-operatively worrying about decompressing nerves, post-op pain, and wrong level surgery and this anxiety pervaded into sleepless nights on many an occasion. It took me a while to get my dissection and blood loss right. It was assumed that a ‘spine patient’ would stay for a minimum of three nights no matter what surgical procedure was carried out and I always worried about whether I’ve decompressed a nerve enough versus destabilising a segment. Add to that the issue of flow of the patient through theatres, instrumentation, pre-habilitation, rehabilitation and overall the whole process of spinal surgery seemed to be quite an arduous task.

In 2017 October, I had the pleasure of being introduced to Robert Masson in Orlando, FL (www.massonsi.com). This was a chance meeting but I ended up observing him in his operating theatre and then having a discussion over what was touted to me as the best sandwich in Orlando (it was pretty good).

Watching him work was interesting. No matter what case he was doing, no matter what he was decompressing and no matter which thoracolumbar level he was operating on, the set up, approach, surgical timing, economy of movement and instrumentation was exactly the same. He ended up doing three major reconstructions of the lumbar spine in one morning (two revisions of cases done elsewhere), with minimal muscle dissection through an incision the size of a £2 coin, consistently. His theatre turn around was -4 (yes, that’s right , minus 4) minutes – but he did have a slick team who knew exactly what to do and had one patient ready while the first was being closed in parallel lists. Overall processes were streamlined, everyone knew their roles and ultimately patients did very well. His fusions go home in 24 hours with a good result.

It is difficult to explain exactly what he does in this article, but in my mind it all stems from a few basic principles applied to the whole range of management of the patient starting from the moment they think about a problem in the back to the ultimate return to function. He doesn’t ask if the patient is able to sleep, work and travel, he asks “are you able to live your life happily”.  Here are the four main principles to keep in mind:

Principle 1) Redundancy – processes follow the same routine every single time. There is no change to the setup, instrumentation and patient flow. This means that there is a lot of play in the system to deal with patient-to-patient differences.

Principle 2) Elimination of unnecessary steps – speaks for itself. This extends to the instrumentation (two trays for every case, be it fusion/decompression/deformity).

Principle 3) Modularity – spinal surgery, the technique, the preparation, the instrumentation and the after care has all been broken down into a set of reproducible core modules, which can be assembled in order of necessity to create the perfectly tailored solution for a patient. It also means that the modules individually all follow a set pattern, which can be taught and reproduced reliably.

Principle 4) This is arguably the most important principle for me – changing our centre of thinking from a disc level to an individual nerve. Therefore, no longer do I ever say to a patient “I will be decompressing your L4/5 disc”. It is always a L5 nerve root decompression including central canal. This is subtle but important. Anatomy at a disc level is not constant but anatomy at pedicle and relationship to nerve is always constant (if there is a pedicle which is almost always the case). We take advantage of this. It saves unnecessary bone resection and muscle damage. Hand in hand therefore is the approach – it is based on accessing this area which avoids massive midline strips, maintains the posterior tension band every time and allows a true muscle splitting approach.

The last thing I took away from that meeting was this piece of advice from Dr Masson: “The most important and difficult part of degenerative spinal surgery is the decompression. Therefore, we must focus our energy on getting a perfect decompression every time. The instrumentation usually supplements the decompression and provides alignment with stability. If I can do the hardest part of an operation through a 2cm incision without defunctioning the posterior tension band, then it should not take more to do the easy part, which is the instrumentation. Furthermore, if we struggle with the instrumentation then we fail to be at our best when we decompress.”

This was an interesting philosophy because in an IMAS TLIF, the instrumentation and inter-body cage is placed before the decompression. This also applies to any lumbar fusion or deformity correction. It also takes a very short time to do it.

Using the anatomical relationships described earlier, a streamlined approach, a modified facet osteotomy and elimination of complex heavy retractors to one or two simple but very effective instruments, the disc is sneakily accessed and prepared safely every time. Revision, primary, deformity, whatever. It’s the same every time.

In summary, this technique took me a lot of time to get my head around, but once I started thinking in this way I could not see how any other way of addressing these issues makes more sense. I will obviously say this because it has worked well for me. I am still open to other ways of thinking. I do not think this is a major change in what we know, but it is looking at it from a different, arguably more streamlined, point of view.

For me it has significantly improved my practice and for the first time I feel somewhat comfortable with my understanding of how to approach everyday spinal problems.

To see the other side of a mountain we can either blow it up and clear the rubble, or we can tunnel through it. The outcome still shows us the other side, but one way is controlled, preserves nature and is effective. The other way is quite destructive. The IMAS technique helps us be controlled yet effective.

About the author

Mr Syed Aftab is a Consultant Spinal Orthopaedic Surgeon at the Royal London (Barts Health NHS Trust). He studied medicine at Pembroke College, Cambridge University and Edinburgh University. He underwent higher surgical training in Orthopaedics and Spinal Surgery on the London NE Thames rotation at the Royal National Orthopaedic Hospital, Stanmore. He also gained a Master of Science at University College London in Trauma and Orthopaedics during his training. Syed completed advanced fellowships in Spinal Surgery at the Royal London Hospital. Furthermore, he continues to broaden his experience with visitations to international centres of excellence for spinal surgery (Antwerp Belgium, Bordeaux France, Neustadt Germany and Orlando USA). Syed has been pioneering the iMAS technique in the UK, using micro access techniques developed by Dr Robert Masson at Neurospine Institute, Orlando, USA (a Federally accredited Centre of Excellence). Syed believes that the best outcomes for patients can only be achieved when decisions are carefully considered and works within the framework of a multidisciplinary team. He is the Clinical Effectiveness Lead for Orthopaedics at the Royal London and is actively involved in teaching other doctors, nurses and allied health professionals. He organizes the ‘Spine Term’ for the Royal London Hospital and Sir Percival Pott Orthopaedic Rotations. Syed has published widely in a number of peer-reviewed medical journals and is actively involved in research into spinal surgery. He has presented at national and international conferences.

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