So we're going to move on now with the abstract presentation. So the first abstract will be Dr. Arce with selective peripheral denervation for cervical dystonia experienced in 110 cases using muscle-splitting lateral approach. And the question will be at the end of the abstract session. Thank you for allowing to the WNAs and the peripheral section for allowing me to present my experience with selective peripheral denervation for cervical dystonia in 110 cases using a muscle-splitting lateral approach. I understand this is an unusual topic for the peripheral section, but I hope I can raise your interest. Cervical dystonia is a focal type of dystonia affecting the cervical musculature, leading to a constant and normal posture of the head and neck, usually in the same direction. In 1979, Dr. Claude Bertrand from Montreal introduced selective peripheral denervation. He treated a patient with a combination of telomotomy and a new peripheral approach. In 1993, he reported a series of 260 patients treated exclusively with a peripheral approach, which he named selective peripheral denervation, with excellent or very good results in 88% of the patients. The main difference of the Bertrand procedure compared with previous approaches is that Bertrand's is a selective denervation of only the muscles involved in the involuntary movement, which is determined not only by the physical exam, but by performing an EMG of the neck musculature. The denervation is tailored to the muscles involved in the abnormal movement, and usually includes a denervation of one of the sternocleidomastoid muscles and a unilateral extradural sectioning of the C1, C2, and the posterior rami, so C3 to C6. There are several reports that follow Bertrand's, and most of them have a 70% to 75% excellent to good results. Selective denervation is a safe procedure with low morbidity. However, one of the problems has been the immediate postoperative pain from the midline incision and approach that require, in most of the cases, several-day hospitalization. And this is the approach from Bertrand. It was a hockey-type incision. Based on our experience with this procedure, we felt a lateral approach would allow a straight trajectory to the nerves without sectioning or producing retraction of the muscles and allowing a faster postoperative recovery. And this is the incision that we performed. By performing an incision starting between the midway, between the mastoid and the ineon, and extending inferiorly, the trapezius muscle can be reflected medially. The splenius is divided or split, and the semispinalis is split. And the dissection continues below this muscle. The nerves are found in this plane using a nerve stimulator. So it's really a very straightforward approach. A hundred and ten patients with four types of cervical dystonia were treated, rotational and retrorotational, lateral torticollis and retrocollis, who were either primary or secondary non-responders to botulinum toxin and were operated on between 2002 and 2014 using this approach. The average degree of rotation for patients, preoperative degree of rotation, for patients with rotational or retrorotational movement was 70 degrees, and for lateral torticollis was 45 degrees. And a quantitative method was used to determine the overall success. Since the main goal of the procedure is to correct the abnormal posture or improve it, we felt success should be measured by determining the degree of head and neck position after the denervation, because that's what the patient is looking for. And this was achieved by measuring the angle of rotation or tilt pre- and postoperatively, and in retrocollis by measuring the distance between the chin and the sternal notch, pre- and post. So for rotational, retrorotational, and lateral torticollis, the result was considered excellent. If the postoperative rotation or tilt varied between 0 to 10 degrees, good, between 10 to 30 degrees, and poor, more than 30 degrees. And this is the way that we measured before and after. For retrocollis, the result was considered excellent when the chin was lower an inch or more from baseline, and poor if it was less than an inch. And this is the way that we measure the distance. If it's more than an inch, we have helped the patient. In 55 patients with rotational torticollis, the results were excellent in 75%. In 33 patients with retrorotational, the results were excellent in 88%. And this is the group that we helped the most. In 12 patients with lateral torticollis, the results were excellent in 77%. And in 9 patients with retrocollis, we were able to bring the chin down at least an inch from baseline. This is the results in the different groups. There was no mortality, and the only morbidity was a superficial infection. All the patients stayed overnight for a 23-hour observation. Most of them did not require pain medication. And actually, now we send many patients home the same day. In conclusion, selective peripheral denervation through a lateral muscle splitting approach allows a fast recovery with significant decrease in the postoperative pain, a short hospital stay, and comparable results to the traditional approach. And this is some of the cases that we have done. This is pre, and this is after the operation. This is pre, and this is after the denervation. This is pre. The patient has a retrorotation. And this is after the denervation. And this is pre. And this is after the denervation. Thank you very much. Yeah. Congratulations. That's very nice. So I'll ask two questions. We'll look at one. What is the durability of the procedure? Because I think in Dr. Bertrand's series, when you look later on, you'll see that the results, there's a lot of people that have, you know, they've occurred because the nerves can regenerate. And second, with Botox, is this procedure even indicated now? Well, most of the cases that I treated are non-responders to Botox. So they are primary and secondary. Now, I don't see the recurrence that you see. In my experience, it's a very small number of patients. And actually, there is no, any paper or any research that says that there is a significant number of recurrences. But most of the patients are very happy. When was your immediate follow-up? 2014, so 10 years to two years. Coming laterally, how far proximal on the dorsal brachii can you get to do this section? And specifically, are you able to see the lateral intermediate branches that are coming out into the muscle to be able to address those? And I think my second question would be, based on the fact that you did this all based on measurements, how do you choose, say, for example, one inch that's being successful? Does that correlate to any function? And how do you account for the fact that maybe this is sort of their best picture as opposed to what they do when they go home? Well, the patients that you are seeing, they vary from 10 years, the pictures, from 10 years to two years. So one patient is 10 years, and the other patient, the last patient, is two years. So I think it lasts. And most of the patients are very happy, actually, after the operation. That's all I can tell you is, you know, how do I base it? It's because if your head is up like that and you bring it at chin, they can look straight. It may not be perfect, but an inch is quite enough for them to be able to look straight. So that's the reason I base it. There is no other reason than what seems to be a comfortable position for the patient. If you have a seven-inch retrocollis and I can bring your chin down, that makes a difference, and they are very happy. I actually could show you pictures of patients with retrocollis. It's very impressive. I think overall it's a good operation. I think it helps a number of patients. I hope more people get interested. I've seen a lot of those patients with Dr. Bertrand and Dr. Bouvier because I was... I worked with Dr. Bertrand and Dr. Bouvier a few years ago, like you, and I've seen a lot of those patients at 5 and 10 years post-op, and then unfortunately there's some movement that tends to come back. It's not as bad as it is like, you know, when they show up to start with, but they do have some elements of rotation or lateral bending, or they will have like some recurrence like later on. But in my experience with those patients, it was 10 years, but it was not like this split technique. The question is, have you seen all of them? Because he operated on almost 260 patients. I've just followed and seen the one that came back because they were no longer there to perform the procedure, so I saw all of them that were not happy after. So we'll have to do a percentage of them. I have patients I have followed for 20 years, and they are doing very well. Thank you.

selective peripheral denervation

cervical dystonia

muscle-splitting lateral approach

head and neck posture

botulinum toxin treatment