Virtual reality, including 3D imaging, will play an increasing role in planning complex spinal deformity surgery in the near future, according to Lawrence Lenke (Division of Spinal Surgery, New York-Presbyterian Och Spine Hospital, New York, USA). At the 5th Annual International Spinal Deformity Symposium (ISDS 2019; 6–7 December; New York, USA), Lenke demonstrated the use of 360-degree virtual planning for complex spinal deformity correction using software developed by Surgical Theater (Los Angeles, CAUSA). Afterwards, he spoke to Spinal News International about technology, the changing role of the surgeon, and, the increasing prevalence of sub-specialisation within the spinal field.
You have been at the forefront of research on the use of 3D imaging in planning for complex spine surgery. To what extent do you see this becoming common practice?
One of the main limitations to the evaluation of complex spinal deformity patients is that we have to look at the separate studies; a CT scan to evaluate the bony components of the deformity; an MRI scan to evaluate the neurologic components of the deformity. For many years now, I have been using 3D printed spinal models of complex spinal deformity patients to prepare and perform these spinal reconstructions. Now, using technology that was initially used in complex brain surgery, we can merge the MRI and CT scans together to create a 3D image that has not only the bony elements of a deformity but also the neurologic elements, the vascular elements and other soft tissues. We can thus create a 3D model of all of these elements that we can manipulate in any perspective we want, including not only external visualisation from any angle, but also internal visualisation going down the spinal canal. From the perspective of planning and understanding the deformity, that is incredibly helpful; even for someone who has been doing deformity surgery for 27 years.
Is there value in employing this technology in simpler surgeries?
Any time you are doing surgery in areas where there are adjacent vascular or neurologic structures that have to be understood. In the cervical spine, for example, I think this would be helpful. Even in a “straightforward” cervical spine impingement, I think surgeons will want to know exactly where that spinal cord impingement is, virtually. Also, in the upper cervical spine, knowing precisely where the vertebral arteries are located in relation to the posterior bony elements would be beneficial. There is the ability now, not only to visualise various spinal cord and nerve impingement, but there are tools that can take structures away. Thus, we can do what is called a virtual laminectomy or corpectomy, on a 3D image we can take away the bone to release the spinal cord and we can do that in the planning phase ahead of time.
So from that perspective, even “simple” spine surgeries could be rehearsed, and especially those that are being done less invasively, where you are not seeing the anatomy as well, seeing this virtually, ahead of time, will help surgeons understand the anatomy when there is not as much visualisation during the surgery. There is definitely a role for “simple” spine surgeries using this technology, which would benefit trainees, as well as practicing spinal surgeons.
How do you see technological advances such as robotics, artificial intelligence and 3D imaging coming together to change the role of the spine surgeon?
One of the key points is that before someone enters the operating room, the physician or surgeon has to decide that the patient requires surgery, and the type of surgical procedure to be performed in the best interests of the patient, which we refer to as patient-informed decision making and consent.
That is the value of still being involved in the discussions with the patients. Having the patients understand the risk-benefit ratio and having multi-disciplinary clinics that evaluate the risks-benefit ratio of patients considering spinal surgery. Thus, I don’t think the physician or surgeon is going away any time soon. The surgeon still needs to be in a position to talk to the patient and figure out exactly what the problem is, what the best treatment is—we need to summarise all of the literature, all of the personal experience we have, to come up with the optimal treatment plan. However, we are going to have devices, tools and robotics that are going to help us with these discussions.
When you joined the field, discussion on spine focused on whether it become its own section within orthopaedic surgery—has it reached a stage that spinal deformity correction could be considered its own specialty?
The more information we have and the more surgeons limit their practice, the more sub-specialisation occurs. When I started my practice, I was an orthopaedic surgeon specialising in spine surgery. Now, I don’t even consider myself an orthopaedic surgeon, I am currently a spinal surgeon with a spinal deformity sub-specialisation. Thus, currently within spine surgery now there are sub-specialisations in spine deformity surgery, cervical spine surgery, lumbar degenerative surgery, minimally invasive surgery, just to name a few. Each of those sub-specialisations, I would anticipate, will ultimately become a specialisation with its own training programmes, and ultimately certifications.
What have been the takeaway messages and themes from this year’s ISDS meeting?
Our goal of finding the optimal spinal alignment in patients, which has been so elusive, is still problematic. One of the reasons is that, although we have a better still understanding what optimal spinal alignment is in patients who don’t have spine pathology, things get much more complicated when various spinal pathologies occur.
Once we start performing instrumentations and fusions and rigidly immobilising various parts of the spine, there is a new normal, basically everyone becomes their own separate database, their own separate articulated chain of spinal segments. What we can apply to one patient at a certain age, with a certain fusion level may not be applicable to another patient who has the same fusion levels, in the same age. It is like your own personalised genomic set point of your spinal alignment. We are slowly realising that and what it means is that we need big data to help us sort out what type of spinal realignment we perform on patients.
We are also going to need this meeting to go on for a long, long time to help figure out exactly what type of surgery we do to best treat patients, to give them the best outcome.