All right, so my name is Lynn Jacques. I'm from UCSF, and it's my distinguished pleasure to introduce Dr. Eric L. Zeiger as your 2018 Klein Lecturer. He is now amongst the list of prestigious lecturer over the years that we did have that has left a very important print into the peripheral nerve surgery field. From Oberlin to MEDA, now Dr. Zeiger is right there on that list. He has put his print as well, as I will mention right now. So he did earn his biochemistry degree in Harvard years ago, Stanford University School of Medicine for his medical degree, and then his residency in MGH in Boston in 1983 to 88. He has done his fellowship at LSU MC under the guidance of Dr. Klein, and he has done some training as well at U of T. Along with being an expert in peripheral nerve surgery, Dr. Zeiger specialized in cerebrovascular surgery and gamma knife procedures as well. Dr. Zeiger research is in clinical and translational in nature and focuses on peripheral nerve repair and regeneration, as well as of many projects in cerebrovascular surgery. He is widely published, is very active and involved in lecturing and teaching in neurosurgical society meetings. He has several publications. We have selected only a few of them to show you, and several awards as well. Some of them are in cerebrovascular surgery, clinical fellowship award, young clinician investigator award, and now is endowed chair, neurosurgical professorship in academic excellence. He has also published books along with his friend and colleague, Dr. Mida. He has also trained several fellows that will continue to bring their wisdom and skills in the peripheral nerve field. So here's the list of his fellows and several medical student. He has been extremely generous of his time. He came at UCSF first Klein Lectureship there, and he has been teaching as well, the cadaver workshop back in October 2017. You can see on these slides I was very active, looking at all peripheral nerve structure along with Dr. Klein, so it was really an honor to have him here. So some things that you might not know about Dr. Zager. He's born and raised in Livingston, New Jersey. He has been in high school a co-captain on undefeated team in the soccer field. He has received John Harvard scholarship for four years, and he started the same on the varsity soccer team at Harvard, so he earned some honors there as well as a senior year. Also, he has a lot of style on soccer field. He has the same cutting waves, also in the snow. So he was doing down kill ski. So be careful if you go in a meeting, you can't find Dr. Zager. He is with his friend and colleague playing tennis, as you can see here. He has also a furry friend that makes him smile every day. Her name is Maya, and he has a wonderful wife that also makes him smile, as you can see here, and he has a very wonderful family that he's proud of. He has two son, one daughter, and you can see his wife just right there. So it is really my privilege to introduce you. Dr. Zager is not only a great neurosurgeon, great teacher, mentor, but he's also my friend, and I'm very proud of that. So without any further delay, Dr. Zager, please. Thank you. Thank you very much, Lynn, that's an introduction that my mother would be proud of, I think, so thanks. Very kind. Do you want me to advance the slides for you or would you like to speak from here? Should I advance from there? If you'd like to. If you'd like to switch to, I can advance. Choice of lecterns here, that's really nice. So this is a great honor for me and I really appreciate Lynn's kind introduction and also for those misguided souls who actually voted for me for this great honor, I thank you as well. That's an incredible list of dignitaries that I'm following, so I'm really humbled by this award and I hope that the message for today will be that even someone like me can succeed if you have a mentor like Dr. Klein, and that's really the point of today. John McGillicuddy gave a great talk at our section meeting a couple of months ago on mentorship and that's really the theme of what I'm going to say is that we work hard, we show grit and so forth as we've heard about in this meeting, but you really need a good mentor and Dr. Klein just fulfills that in every way. So let me move on, I have no disclosures for this talk. And this is actually a view of Lynn and Dr. Klein this fall when Lynn was kind enough to invite me as the first Klein lecturer at UCSF and Dr. Klein and his family were there and it was a terrific cadaver dissection course and teaching session for their residents and fellows and it was a great honor for me. And here's Dr. Klein with Jonathan Brashears who's one of the chief residents at UCSF and Dr. Klein is demonstrating, talking about his famous dachshund dog story which is a classic story of how he got started in peripheral nerve surgery in the military at Walter Reed and it's a great story and I'm not going to try to summarize it for you because only Dr. Klein can tell this story so if you haven't heard it, please ask him to share that great vignette with you. My origins in peripheral nerve were a bit different, some of my residents actually walked in, that's a surprise, thank you. And you know, I finished my training at Mass General and I thought I was pretty well trained, I had excellent mentors there, Dr. Ojiman, Dr. Harrows, Dr. Zervas, Chapman, Paletti, I mean just a long list of terrific mentors. And I felt pretty confident about my skills in cerebrovascular surgery, tumor surgery, spine and so forth but I thought about the field of peripheral nerve and I felt woefully deficient. At that time there was a colleague that Dr. Klein knows very well named Robert Leffert who was a great orthopedic surgeon who was really a pioneer in brachial plexus surgery at the time and he trained his residents in brachial plexus surgery and peripheral nerve surgery and they were very knowledgeable and sharp in all of those areas but the neurosurgery residents didn't get an exposure to Dr. Leffert unfortunately. And so I felt deficient because the orthopedic residents were finishing residency knowing more about the brachial plexus than I did. So what do you do? I was interested in nerve, I didn't know if that would be my career or not but I said well they do have these CNS clinical fellowships available so I applied for one of those and they don't pay you well but they give you some travel funds and there were really only two places in North America at that time to get adequate training in peripheral nerve and these are the two gentlemen that were responsible for that training, Dr. Klein obviously on the right and Dr. Hudson on the left and they were terrific colleagues, friends, mentors and so I decided to spend a few months with each of them and I first went up to Toronto with Dr. Hudson who was in the process of actually conglomerating the Toronto program but spent some time with him at St. Michael's and phenomenal surgeon, phenomenal anatomist and teacher and also since he was in meetings all the time trying to coordinate the different departments he left me alone in the operating room a lot to sort of muddle my way through the brachial plexus and kind of on the job training so it was a terrific experience with Dr. Hudson and then I went down here to Charity Hospital and the origins of this story are, it's very nostalgic for me to come back this month to see what used to be Charity Hospital, it's actually 29 years ago this month that I started my fellowship with Dr. Klein, time flies, so you know if you think back in the origins of this place at the time in the 1930s this hospital had over 2,000 beds, close to 3,000 beds, it was the second largest hospital in the country and you know it was as its name implies a charity hospital for the poor and Dr. Klein ran the program there for the LSU residents and we also worked at the Ochsner Clinic and so forth and the story also goes back to Charles Wilson another giant in our field who unfortunately passed away this year and there were memorials for him this week but he actually made room for Dr. Klein because he was, he trained at Tulane and Ochsner and actually joined the general surgery faculty at LSU under Dr. Cohn and was fired which is a good story for perseverance, right, he ultimately succeeded and then when he left here, New Orleans went to Kentucky and then obviously built the department to its current fame at UCSF but then in came two other neurosurgeons, Peter Ginetta who was actually trained first in general surgery at Penn and then as you know went on to UCLA in Pittsburgh and then Dr. Klein who many of you know did both his undergraduate and medical school training at Penn as well and then neurosurgery at Michigan and then on to Walter Reed and here so that's the arrival of Dr. Klein, of course there's this great book about Dr. Wilson by Brian Andrews, the Cherokee neurosurgeon which I commend to all of you but here's Dr. Klein showing early leadership skills as the captain of the varsity wrestling team at the University of Pennsylvania, he's the spry fellow on the right who's clearly in control of the match and I'm sure won this match handily and has shown leadership skills ever since and here he is photo by Raj Mitta, Dr. Klein in China at one of our Sunderland meetings in 2009 showing his leadership skills as a terracotta warrior and of course now he's been honored in many ways including at LSU as the Boyd professor and here one of my favorite pictures of three of the giants in nerve in the world at that Sunderland meeting in Shanghai in 2009, Hanno Malessi on the left who sadly passed away last year, Professor Yudong Gu in the middle who has pioneered many things in nerve including nerve transfers and of course Dr. Klein who we know his contributions very well. So I'm going to briefly summarize what we've learned from Dr. Klein over the years and in three basic areas that we all are familiar with, nerve trauma, tumors and entrapments and of course you know you can get much more information from his famous books which ought to be part of all of your libraries, I'm sure they are and I refer to them regularly even years later. I hope most of you got a chance to see the video this morning that Michael Schulter helped to organize about Dr. Klein and the response to the tragedy of Katrina. It was really a heroic episode and Dr. Klein served as a role model for residents, medical students and the whole staff at Charity in the response to saving those patients at Charity Hospital who were suffering in 90 degree heat with no electricity for days without rescue. So he summarized this in the Journal of Neurosurgery article in 2007. I recommend that to all of you to read, it's really very moving and a wonderfully written account of that time. Here are just some quick photos of Charity Hospital following Katrina and the attempts to salvage it but of course you know it's since been condemned and it's a very sad chapter. But Gabe Tender and Rob Spinner and Dr. Klein have resurrected the program, especially this legacy course which I also recommend highly to all of you. We just had the fourth annual meeting this past January and it's a terrific cadaver dissection course which has an excellent faculty and I recommend that all of you try to attend or send your residents to this course because it's just outstanding and there's room for next year. I think it's in mid-February and I strongly recommend you take advantage of that. Here's just a quick photo of the night before our dinner at Antoine's of the faculty with Raj and Rob Spinner and Nell and Dr. Klein with their famous baked Alaska. Here's Gabe Tender demonstrating with Dr. Klein the peripheral nerve exam at the course and if you folks haven't had the privilege of seeing Dr. Klein demonstrating the peripheral nerve exam, it's really something you shouldn't miss. So I know he's signed up for next year and I recommend you see this exam because it's really invaluable training to the basics of peripheral nerve. As you know, peripheral nerve is one of the few remaining specialties in which the exam and the history are still more important than the imaging studies, right? Think about what else we do in neurosurgery. Imaging is everything but not for peripheral nerve. So it's a true bastion of the basic clinician. And of course at that course is Leo Happel who is still very active in teaching us about electrophysiology, interoperative, preoperative, postoperative studies and he teaches at the course. There's Dr. Klein at the cadaver demonstrating the posterior subscapular approach which he championed, of course, for approaches to the lower elements of the brachial plexus. And even Nell got her hands in there and attended the course this year. So I want to have just a sad moment to reflect on one of our kind colleagues, Bob Teel, who sadly passed away prematurely years ago. And I've, since whenever I demonstrate the anatomy of the plexus, I have changed the mnemonic a bit from Robert Taylor to Robert Teel drinks cold beer to remember the elements of the brachial plexus. So we all fondly remember Bob and the lessons he taught us. So I just want to mention briefly some of the nerve trauma, things we've learned from Dr. Klein, of course, the history is everything. The mechanism is so important in what we expect to find in our patients, and it really informs our decision-making in terms of management, whether to manage someone conservatively or to operate, and also to tell us about the timing of intervention. And, of course, Dr. Klein emphasizes that most injuries that we see in a peripheral nerve practice leave the nerve grossly in continuity. And that, of course, tells us we have to make decisions based on a nerve that's still in continuity. How do you know how to manage that? Well, Dr. Klein spent an important part of his career investigating that, first in animal studies and then in a series of thousands of patients in which he studied electrophysiology of the nerve in the operating room. And this is something that all of us as his students have learned, and that is that unless you understand what's going on internally in a nerve, you can't make decisions based on the external appearance of a nerve. And even imaging studies, which perhaps are trying to get at that question, don't match up to the electrophysiology. So that's an important lesson from Dr. Klein's years of research into this field. So it's the evaluation of the neuroma in continuity that is one of the most basic fundamental contributions that he's made. The electrophysiological studies in the operating room really inform us. And you can know everything about the Sunderland and Seddon classifications, and they are important, but it's really the studies at the operating table that tell us what to do with that neuroma. Do we resect it? Do we graft it? Do we just neuralyze it and leave it alone? And that really has an important impact on our patient's course. So we know about the extremes, the neuropraxia we leave alone, the neurotmesis, all need to be repaired. It's just a question of acutely or in delayed fashion. But what about this large group in the middle of axonotmesis? How do we manage those? Well, we follow them. We study them carefully clinically. We study them electrophysiologically. And then we make decisions, if we do operate, how to manage that neuroma in continuity. We all know about the rule of threes. We've heard about these. We've learned about these. We use these. But the injuries in continuity is where most of the difficult decision-making comes in. This is a nice chapter that Lynn Jacques wrote with Dr. Klein on the pathophysiology of peripheral nerve injury and the fundamentals of management decisions, which I also recommend you look at. Here's Lynn and her favorite activity, mountain climbing, somewhere in the world. I don't know where that was. She also wrote a great early article on functional outcome of brachial plexus trauma, of reconstruction after brachial plexus trauma. So that's a good thing for you to focus on. The outcome studies are so important. I'm going to skip through the open injuries quickly and just remind you. Here's a case in which a stab wound to the neck required an emergent sternotomy and neck exploration by the trauma and vascular service for vascular repair. And then after the dust had cleared and the patient's limb was salvaged, then we realized that there was an upper and middle trunk injury. It's a sharp mechanism, so that needs early surgery. So on the second day, after stabilization from the vascular injury, we explored the neck and found, in fact, that the upper and middle trunks were cleanly sectioned. And of course, there is some elastic recoil, but we could make up that relatively short gap by neuralyzing distally and proximally and doing a primary epineurial repair, shown here, and that is the best chance for a good outcome with a sharp mechanism. We don't see many of these, but it's important to recognize them. Too many of these I see late, and by then you need to do grafts. So here's a daycare center nightmare, a three-year-old baby who pulled a fish tank at the daycare center off the table. The glass shattered and pierced the supraclavicular fossa of this baby. This was stitched up in the emergency room. Fortunately, there was no vascular injury, but the child had a completely flail arm. So you're called to manage that. Well, it's a sharp mechanism, right? So we explored the next day and found that the entire supraclavicular plexus was sectioned just above the clavicle. It's the clavicle. And so we had to dig underneath infraclavicular to free up the divisions and cords that had sort of recoiled a bit, and we were able to do a primary repair of that entire plexus. And it's a baby, so you have a chance, right, of even getting hand function back. Here at 18 months postoperatively, the upper arm is doing beautifully, and even some finger flexion and extension is just starting to occur. That won't happen in our adults, but a three-year-old, it's a very gratifying procedure to do. The closed injuries, as I indicated, are more common, and they're more difficult to manage because it's not so clear what to do with these. So we study them clinically, do our baseline electrodiagnostic studies at about three weeks or so, and then we follow the exam carefully every month until we see if there's a neuropraxic injury, it's going to make a nice recovery. But if it's not, if there's a major element that is not recovering confirmed by your clinical exam and your electrodiagnostic studies, then you have to explore. And you're prepared for intraoperative studies and possible nerve grafts or nerve transfers. And unfortunately, in my neck of the woods, most of these injuries tend to be motorcycle accidents, which leave people horribly maimed, and many of these involve avulsion injuries of the plexus, as you can see with the CT myelogram. We also see, unfortunately, way too many iatrogenic injuries, and no matter how often we lecture about protecting nerves and what we have to do to repair nerves, we still see these injuries from many different fields of surgery and radiology, invasive procedures of all types. And so those are very sad. Gunshot wounds, unfortunately, are still a big problem, and here's a civilian gunshot wound with a small caliber bullet, but causing a pretty devastating infraclavicular brachial plexus injury. We treat these really as closed injuries, because with the civilian gunshot wounds, they're low-velocity, small-caliber missiles in most cases. And of course, if there's an indication for a general surgery intervention, vascular, orthopedic, et cetera, then that takes precedence. But the nerves we typically leave alone acutely, right? We follow those, and some of them don't get better, but many of them do. In fact, the majority do show some signs of improvement. But here's a nerve, not in the plexus, it's a sciatic nerve, in fact, that was cleanly sectioned by a bullet, and we followed this because we didn't know this. Perhaps imaging might have shown us this, but at this time, we didn't have access to good quality MR and ultrasound, so we didn't know that this was cleanly sectioned. And once we neuralized it, there was a bridge of tissue that looked sort of like nerve, part of it, so we thought perhaps we could salvage something. But in fact, we do our electrodiagnostic studies, our nerve action potentials, in the operating room. You can't tell from the outside whether it looks like this, and the nerve is actually regenerating and has a nice nerve action potential, or whether it's a complete section with a big neuroma here. But the electrodiagnostic studies tell you the nerve, there's no flat tracing for the NAP in this case. So we do our NAPs, that's a different case, and this tells you the outcomes. This is an early slide, but it still makes the same point from Dr. Klein's large series, that if you have an NAP present, 94% of the time, you're going to make a good functional recovery. And when it says grade three, this is the LSU scale, which means that's not just antigravity, like in the MRC scale, the LSU scale means that you have antigravity and can overcome some resistance. So it's really a three plus or a four on the MRC scale. And so these are good functional outcomes, 94% of the time. So the NAP really tells us how to manage these. So these patients just had neuralysis and made a beautiful recovery, but if you have to do a repair, depending on which element you're dealing with, you're going to drop down to the 50% to 60% range for a successful outcome. So it's really an important decision, and it's something that when you see people doing nerve work, evaluating neuromas in continuity without electrodiagnostic studies in the OR, they're really doing a disservice to their patients. So that's, again, a huge contribution by Dr. Klein. And then, of course, if we do have to resect a neuroma, we do this bread loafing or slicing technique with a sharp knife. And at first, you see nothing but scar tissue. This is that nerve I showed you with a gunshot wound through it. And there, if you keep slicing, sectioning back, you finally see some healthy-looking fascicles. And ultimately, you want to see what this beautiful picture that Raj provided of a healthy peripheral nerve looks like. And only by seeing a healthy nerve like that are you going to be able to get some sort of recovery. If you graft scar to scar, it's not going to work. So of course, we harvest the serral nerve. Some do it with the open technique. I prefer to do a series of small incisions or even do it endoscopically, which, for us, takes a long time. But Martijn Malesi does it beautifully here in a baby with two incisions. And then you do your serral cable nerve graft and suture it into place and a little fiber and glue, and you hope for the best. Now what about the delayed presentations? We see way too many of these sharp injuries that are not recognized as injuries. And here's a median nerve laceration at the wrist that was not handled appropriately. It was just sutured shut, and they didn't recognize that the patient had a complete median nerve deficit. So when we explored that, we also released the nerve at the carpal tunnel just to make sure there was nothing to impede regeneration, but the nerve was completely sectioned here. So again, we bread loaf it, slice it back until we see nice glistening fascicles, and then lay in our serral nerve cable graft. We also have the option now of using nerve conduits, and I see Simon Archibald in the audience, and many of you know that he did some of the earliest work on the development of these nerve conduits and studied the biology of nerve regeneration. And now we have quite a few available conduits for clinical use, and the important message here is that they work as well as serral nerve if the gap is short. And so it is an option for us now, and there are examples of people using it even for longer gaps and in mixed nerves with some results, but as far as I'm aware, it hasn't been proven to be as good or better than serral nerve for nerve repair, but it's an option for us. What about the cases of terrible stretch injuries in which you have to use very long serral nerve grafts? Well, we know that the outcomes are not as good. If the grafts are longer than 15 or 20 centimeters in length, we're not going to have good outcomes. And the other example of poor outcomes are cases where there's a root avulsion, as shown here and on the earlier slides, and some of these can be dramatic pseudomeningoceles or even tiny ones, but the good MR Fiesta sequence shows us that the roots are avulsed in a case like this. Subtle pseudomeningocele, but you don't see the nice rootlets that you see on the other side. So how do we manage those? Well, nerve transfers have really transformed the way we work in nerve trauma, and of course these have become incredibly popular for good reason, because they really salvage a lot of difficult situations of root avulsions or long proximal injuries. And of course, the one that's the favorite for all of us has been the Oberlin procedure because it works just so well and has so little morbidity that it has restored such an important function in the upper extremity following a root avulsion or a bad proximal injury. So we still do explore the plexus, as shown here, but if we can't do a good repair because of avulsion or we're worried that the grafts are way too long, we have the option, if the hand is working, of doing an Oberlin repair and taking a fascicle of the ulnar nerve or the median and opposing that to usually the biceps branch of the musculocutaneous nerve, as shown here. And that works very, very well. You have the option of doing a double fascicular transfer and getting two chances to reinnervate, but it hasn't yet been clearly proven that this is better than the single Oberlin. And this is actually a case from LSU that Dr. Klein and Dr. Thiel worked on some years ago, and they did both a medial pectoral nerve to musculocutaneous nerve transfer in the infraclavicular fossa and also did an Oberlin procedure. And here's a patient demonstrating a really powerful biceps recovery, able to lift up Sir Sidney's massive textbook. So that's a great outcome of that nerve transfer. And age doesn't seem to be a huge barrier, which I was skeptical about. But here's a patient of mine, 71 years old. He had a shoulder dislocation, a complete axillary nerve injury with no recovery. I think at about six months, we explored and did this, since he was a bit late and elderly, we decided to do a radial nerve triceps branch transfer to the axillary nerve. And look at him about a year later, beautiful recovery of shoulder abduction from the deltoid. So here's a listing of some of the nerve transfers we do. The top ones are really the mainstay of getting our upper arm recovery, and this is a potpourri of some of the other transfers. I think the contralateral C7 is common only in China. We still have reservations about it in other parts of the world. So I want to shift quickly to nerve tumors and just highlight some of the contributions again of Dr. Klein and what we've learned about management of nerve tumors. Diagnosis is important. It's in the distribution of a nerve. It's a mass that's typically painless or just sensitive to manipulation. There's usually no deficit with these unless they get very large or they're aggressive lesions, but I'm talking about the benign nerve sheath tumors, which are usually schwannomas and neurofibromas. And MR imaging is really the modality of choice. There are other modalities of radiologic evaluation that are important, and sometimes these tumors show up on even plain X-ray or CT scan. But here's the classic appearance of a nerve sheath tumor on MR, beautifully illustrated with the nerve entering and exiting. Ultrasound can even show the fascicles, and other types of MR imaging like DTI can show the fascicles. But a CT scan will give you the diagnosis too. I mean, what is that? Look at those neuroforamina. They're enormous, every level. Well, it's got to be type 1 neurofibromatosis. There's nothing else that looks like that, so it shows up on the CT scan. Even plain films can show you something like that. So when do we intervene? The indications are somewhat soft. They're not rigid. But certainly if it's symptomatic, enlarging, a sizable tumor, it needs surgical intervention. There's nothing that replaces surgery. question of whether to do a biopsy or not, well, Dr. Klein's studies have shown that the patients who get the biopsies before you get a chance to resect it, they do worse because you've lost your surgical planes. You've had scarring. You've had bleeding. You have deficits. You have pain. So, the biopsy for a benign lesion is not the way to go. Now, of course, if you're suspecting a malignant tumor, rapid growth, severe pain, progressive deficits, then a biopsy certainly may be appropriate because the operation will be different. It will be a cancer operation if it's a malignant tumor, of course. And then preparing your anesthesia properly and having your monitoring in place is very important in taking these lesions out. And some of these tumors may look ugly with internal, you know, hypodensities or hypointensities or lack of enhancement. It looks like a, you know, if this were a brain tumor, it'd be a glioblastoma, right? But that's a schwannoma, a typical appearance of a benign tumor. And at surgery, you're looking for that clean capsular plane and preserving the nerve. Steve Russell and Dr. Klein have emphasized this. Preserve the nerve and don't give the patient a new deficit. These are benign tumors. They're not going to die from them, so don't give them a major deficit. And usually, you can find one fascicle entering and exiting the tumor. When Dr. Klein did electrical studies of these shown here, he found that these were flat tracings. That's the stem artifact. And those were non-functioning fascicles that entered and became tumors. So you could take those without a deficit. And in schwannomas, 90-plus percent of the time, we're able to get the tumor out completely and not leave the patient with a deficit. One of his other important contributions was in recognizing that neurofibromas are resectable without dividing the nerve. Before he recognized this, people were—general surgeons were just cutting the nerve and taking it out with the tumor and then perhaps trying a nerve graft. Well, that's a great disservice to these patients because most of the time, if you do a fascicular dissection, you can find a plane and preserve most of the functioning fascicles. Not as easily as in a schwannoma, and the results are not quite as good. But the vast majority, the over 80 percent of these patients can escape a surgery and get the tumor out without a major deficit. So another important contribution from Dr. Klein. And here's just showing this fairly large neurofibroma in the supraclavicular plexus. And here you see several fascicles entering that tumor, and that is resectable without a deficit. The plexiform tumors are a different story, and these are not good surgical candidates. And we really wrestle with these because if they become large and symptomatic, number one, we worry about malignancy, and they may need a biopsy. But number two, we don't really have good surgical approaches to these because you take out that tumor, you're taking out the plexus. And so there are exceptions, and there are cases that you should consider carefully. This is a young musician, 21 years old, who showed up with this massive tumor. He's got neurofibromatosis. And he basically, his mother is a nurse, and he said, his mother and he said, well, I can't have surgery on this. I'll lose my dominant arm. But he finally got to the point where he couldn't play his guitar because every time he turned his head or flexed his neck, he would get these electrical sensations down the arm, and it was even developing some deficit. If you study this carefully, you'll actually see that the brachial plexus is not directly involved. All of this is cervical plexus. And you can operate on a plexiform tumor of the cervical plexus. You may lose a little sensation, but you're not going to wreck his arm. So studying the imaging is really important. So most of the bulk of this was in the cervical plexus. Of course, you're not curing his tumor here, but you're trying to palliate him and allow him not to walk around looking like this, like he has another head. So we approached this. You see his cafe au lait spots. And we were able to carefully dissect this away from the brachial plexus and took out a large portion of the cervical plexus. We did preserve some supraclavicular sensory branches here. But there's the brachial plexus after debulking this massive tumor, and we were able to preserve that. And he walked away without a deficit and a much better cosmetic and functional result. So it's a lesson that some of these tumors you don't give up on, and you can help people. But obviously, it has to be done carefully with the proper planning. That was gallons of tumor taken out. For some of the less common non-neural sheath tumors, I refer you to this nice summary by Dr. Jacques in Neurosurgery Focus on non-neural sheath tumors. I don't have time to talk about them. It's a long listing. If you look in Dr. Klein's textbook, you'll see a long listing of a variety of tumors that can affect the plexus and other peripheral nerves. And Rob Spinner's written about even things like lymphoma in nerve that you can identify on fascicular biopsies. Finally, I'll finish with entrapment neuropathies. These sound somewhat mundane, but there are actually still quite a few controversies about entrapments. And I'll highlight a couple of them briefly. Imaging has become more and more important in entrapments, especially the uncommon entrapments. We still use ultrasound for things like carpal tunnel and ulnar nerve if there's something unusual about the case. But MR imaging for all of the unusual entrapments, because occasionally you'll find a tumor or you'll find an anatomic anomaly. So imaging has become important. Endoscopic techniques are here to stay, I think, certainly for carpal tunnel and maybe for some other entrapments. And then the uncommon entrapments, most of them are dilemmas of diagnosis. Things like painful entrapments, radial tunnel, disputed neurogenic thoracic outlet, piriformis, pudendal, I mean, you name it. There are more controversies than we have answers for. And finally, I don't have much time to talk about this, but the whole concept of diabetic neuropathy and whether that's a surgical disorder or not. Ten years ago it was heresy to think about, but now we have randomized controlled trials, which we don't know the outcome of yet, but this may become a part of our practice. And I'll touch on that. So imaging, Aaron Filler, who I think I saw at least last night at dinner, yeah, there he is in the front row. He really pioneered this, along with Michelle Cleo and some radiologists, looking at beautiful images of the median nerve here in the carpal tunnel along with the flexor tendons and showing how much movement there is of nerve between flexion and extension. And this has become important for entrapments. Ultrasound shows carpal tunnel beautifully, and there's validated studies that makes it an option instead of a repeat EMG. You can get an ultrasound, a lot less painful for an entrapment neuropathy. So it's a good option. Endoscopic techniques I mentioned. Many hand surgeons, some neurosurgeons do this endoscopically in the carpal tunnel. Not so clear if it really has a role. One study suggests it doesn't. And elsewhere in the body, we don't know yet. There's just been a few studies looking at other locations like the brachial plexus, but perhaps the endoscope will play a role in biopsying something, perhaps in the plexus or lumbosacral plexus. And our friend Kartik Krishnan from Germany, as you know, is fully trained as a neurosurgeon and a plastic surgeon. He's really pioneered a system of endoscopic surgery using a retractor, and just shows nerves beautifully. And this is useful for entrapments. Zarina Ali and I at Penn have tried out this system, and it does work. It gives you beautiful views of nerve. Here's Zarina demonstrating it in an endoscopic PIN decompression. And you get these beautiful images of the arcade here. Here's the nerve passing under this tight fascial band of the arcade. And Zarina's dividing the arcade here. And the images are just beautiful, the lighting, the magnification. It just takes practice to learn how to handle an endoscope in a tight space. But I think it's something that's worth looking into. What about controversial things like thoracic outlet syndrome? Rarely do we see the true Gilead-Sumner hand, as demonstrated here, with atrophy of both the thenar and the hypothenar eminence, both the median and ulnar nerve distribution. Much more commonly, we see the painful form. Well, this is a huge cervical rib. Why doesn't that patient have true neurogenic thoracic outlet syndrome? He had no deficit. He had pain. And he had a car accident. And he had a lawyer. So it's a bad prognostic sign, right? Well, I couldn't ignore that rib. And he had tried and failed all forms of conservative management. So I operated on him, and he was very happy. So I think there are intermediate forms between true neurogenic, which is rare, and the painful neurogenic or disputed neurogenic thoracic outlet. I think it's more a continuum than two separate categories in which we should never go to the painful one and always operate on the disputed. I think there's a gray area. And there's room for surgical intervention in some of these carefully selected patients. MR neurography may help us. And Aaron, again, has shown some beautiful images of distorted C8, T1 lower trunk elements with a fibrous band that you can't see well on other imaging studies. I haven't been so lucky in my MR neurography experience, but I'm still hopeful that I will gain more experience with it. If you see anatomic structures like the cervical rib, make sure that that's really the culprit. Very often, it's not the rib. It's not the bone. It's the soft tissue that causes the problem. Be prepared to take out bone if it's in the way. But very often, we'll find a fibrous band that's really causing the problem and then feel the rib and realize that's not really causing any trouble on the lower elements of the plexus. There's a big cervical rib right there. And again, another very nice summary of neurogenic thoracic outlet current diagnostic criteria and advances, again, by Lynn Jacques and her group at UCSF, which I recommend from a couple of years ago. And now, something completely different, and that's Lee Dellen. Just to finish up with controversy, as many of you know, he has championed the idea for a couple of decades now, since the 90s, that diabetic neuropathy may, in fact, be a surgical disorder. And he's done some laboratory animal studies, and he's done a series of now hundreds of patients in which he decompresses the common perineal, the deep perineal, and the tarsal tunnel in diabetics if they have a TINEL sign, and he can demonstrate entrapment. And he claims that he reduces pain. He improves their balance, improves their sensory function, reduces the number of falls, the number of ulcerations, and number of amputations. None of that has been proven with good randomized controlled trials. But there is a study now done by one of his former fellows, which we're awaiting the results of and awaiting the publication for. But perhaps this has some merit. We don't know. And I'm not going to spend more time on it, but it's something at least to pay attention to the literature in the months ahead, because I think we're going to learn whether there's a role for this or not. Sounds a little crazy, but maybe it's not. Finally, I'll just finish with some fun pictures, Dr. Klein and Nell in China, and with grandchildren, with his current house in the woods at Mardi Gras some years ago, and one of his visits to Penn as our visiting professor, and in his course, in Gabe's course at LSU recently, at the Sunderland meeting just recently with Dr. Hudson, a reunion for the two of them, chairing the session again. It was great to see them. And a mention of other friends in the field. Raj and I have gone back a long time. I'm honored to follow him as the Klein lecturer. Tessa Gordon, I'm sure all of you know, has inspired all of us with her studies of nerve regeneration, and we're still learning every year. Raj was kind enough to invite me to co-edit this textbook, which he slaved away at for years, and we finally got it published, so I'm proud of that. Martijn Malessi, great friend from Leiden and recent president of the ASPN, another meeting I commend to all of you to attend. You've seen my tennis buddies, the Sunderland group in Germany, and more recently at Stanford. Great group. The Stanford meeting was organized by Michelle, who couldn't be here, and by Rob, of course. I also don't want to forget my colleagues from South America, the Brazilian and Argentinian group. Lucas, who is here, from Serbia, and other friends from around the world. It's really a great international community of nerve surgeons. These are the Brazilians, great hosts. And Linda, who of course is not here either, but with Fernando from Rio. John McGillicuddy, Bob Teal, nice photo from years ago. And I also have to thank my team at Penn for supporting me. Glad the residents came to support us. This is in the old days, when we had a good softball team. We actually won the charity softball tournament two years in a row. I'm proud of that, but hopefully we'll return to that former glory. Here's the department more recently. It's grown. When I got to Penn, it was four neurosurgeons. Now we have 22 faculty members. Amazing growth under Sean Grady's leadership. And just a few of my former trainees. Jason Wong, shown here in the Iraq War, is now a chairman of neurosurgery in Texas, and he has a residency program. So I'm really proud of Jason. He did some of the early work here with me, a nice volume on tumors. And he did some of the early work with Doug Smith in our department on axonal stretch, which is a really amazing contribution, I think, to understanding and hopefully treating some long gaps. But the stretch growth concept made it to the cover of our journal. And you see these amazing fasciculated stretch-grown axon tracts that may serve someday as living nerve constructs for peripheral nerve gaps and perhaps even spinal cord and brain injuries. So there are folks in our department who are still investigating this. I want to again point out Zarina and also Greg Hoyer in our department, who's at CHOP, two of our trainees who are carrying on the tradition and allowing me to still continue to do some peripheral nerve work while they gradually take over that task. And then you've seen some of my former fellows who I'm proud of. And finally, I want to thank my wife, Maria Rosa, who's here today. She rarely comes to meetings, but I think it was the Jazz Fest more than this talk that got her to come to this meeting. But she has supported me and tolerated me and put up with my travel and long hours and so forth. So I really thank her for all your support. And finally, you've seen pictures of our kids on our boat and our dog. They're great. They're really young and having fun. So it's a great group. Anyway, I want to thank you all again for your attention. Thank you to Dr. Klein for your mentorship, and thanks for allowing me to spend all this time talking to you. Thank you again. Thank you.

Dr. Eric L. Zeiger

Klein Lectureship

peripheral nerve surgery

cerebrovascular surgery

gamma knife procedures

nerve repair and regeneration

nerve trauma

nerve tumors