Two and half weeks ago, I completed my 8-week surgery rotation. Doing one or two clinical clerkships before starting the PhD is optional at Michigan, but taking this option is one decision I'm very happy about. For one, I got to see what being a doctor is all about, and I won't be worrying for the next four years about whether I have what it takes. I also got to see how all the facts I was memorizing for the past two years come into play in real life. And finally, I got to join my classmates during the most challenging transition of their careers, and I got to work closely with a few classmates that I had not worked with before. I strongly recommend splitting the M3 year for any MD/PhD student--I actually think it should be mandatory at most schools.
The first month I was on the General Surgery-White service, which is mostly gastrointestinal surgery. The second month I was on the transplant service, with a one-week stint on the neurosurgery service. The transplant service was the most enjoyable because the professors and fellows spent a significant amount of time teaching medical students. We were also required to make a 15-minute presentation on a topic in transplant; I did mine on organ sales. Some of the surgeries I saw over the two months included laparoscopic cholecystectomy, liver resection, Frey procedure for chronic pancreatitis, bowel resection, peritoneal window for a lymphocele, nephrectomy, and kidney transplant. Unfortunately I missed out on a liver transplant and Whipple procedure for pancreatic/bile duct cancer, which are big operations also performed on the services I rotated on. Overall I had a great time on surgery, but I don't think my skill set or scientific interests are aligned with a career in surgery.
While on neurosurgery, I saw several procedures on the spine as well as a temporal lobectomy for epilepsy. I wondered what sorts of surgery are available for epilepsy, how often it is performed, and how successful it is. Below is some interesting information I found.
Surgery is considered for epilepsy patients who have not responded to sufficient trials of anti-epileptic drugs (AEDs) and who have a reasonable chance of benefiting from surgery. What is considered "sufficient trials" is not set in stone, as an estimated 300 years would be required to try all AEDs in all combinations. Patients who benefit from surgery have what are called "complex partial" seizures, which means that their seizures originate in a defined focus in the brain and cause them to lose consciousness.
Before surgery, a number of tests must be performed. A brain MRI is taken to assess brain structure. An electroencephalogram (EEG) is commonly used to diagnose epilepsy but is usually not used to make major surgical decisions. Neuropsychological testing can determine the patient's baseline attention, concentration, language, visuospatial skills, verbal and visual memory, problem solving, personality, and emotional functioning. Many of these skills are carried out by distinct regions of the brain, so a patient's performance on the tests can tell physicians where the epileptogenic focus lies. The intracarotid amobarbital (Wada) test, in which the left and right sides of the brain are anesthetized one at a time, permits determination of language and memory lateralization. If a patient can accurately recall 75% of items presented during anesthetization, then the hemisphere contralateral to the one anesthetized should be able to support memory after the anesthetized hemisphere undergoes surgery. If the above non-invasive methods still leave ambiguities in the surgical plan, then invasive intracranial monitoring can be performed by placing electrodes in the space under the dura mater, the connective tissue sheath surrounding the brain.
There are four operations that can be performed for epilepsy:
1. Anteromedial temporal resection (AMTR): Excision of the amygdala (fear conditioning), hippocampal head and body (memory), uncus, entorhinal region (spatial memories), and the parahippocampal gyrus (memory encoding), and a variable portion of the tip of the temporal lobe. This is the most commonly performed procedure for epilepsy, as the medial temporal lobe is a common location of epileptogenic foci.
2) Corpus callosotomy: Disconnection of communication between the two brain hemispheres. Usually only the anterior portion of the connection wires are broken.
3) Functional hemispherectomy: One side of the brain is disconnected from all other structures, but the brain remains in place (actually removing one side of the brain increases morbidity).
4) Multiple subpial transection: Cuts are made perpendicular to the brain surface in the epileptogenic focus. The idea is that the cuts will disrupt side-to-side connections between neurons that cause a seizure to spread, while preserving connections from the outer most layer of the brain to the inner layers.
A 2011 study showed that in a cohort of 615 adults who underwent epilepsy surgery, 52% remained seizure-free five years post-op (excluding small seizures that did not cause the patient to lose consciousness). Patients with medial temporal lobe epilepsy can benefit from AMTR early in their disease course, even though the average waiting period for patients to undergo epilepsy surgery is currently 20 years. Corpus callosotomy usually decreases but does not stop seizures, as more than 80% of patients experience a 60-70% decrease in seizures (but 10-15% of patients get no benefit). Amazingly, cutting off communication between the brain hemispheres has remarkably few side effects. Occasionally patients have transient paralysis in part of their body or temporary bladder incontinence. While psychological studies can detect impaired inter-hemisphere communication, this does not interfere with patients' daily living. Similarly, functional hemispherectomy has a seizure-free outcome in 54-90% of patients, with the only common long-term complication being impaired motor function of the contralateral hand.
One more detail to add from the temporal lobectomy that I witnessed: rather than remove brain tissue en bloc, the surgeons used a suction device. Brain tissue was sucked up by the sucker, which made a horrible noise, and sent to waste!
In the future, I wonder if epilepsy surgeons will not be removing brain tissue, but possibly modifying it by injecting drugs or stem cells that would stabilize the electrical activity? Unfortunately we don't know how most epilepsy drugs work (hence the trial and error in selection and dosing), but if we figure that out, perhaps more targeted therapies carried out by surgeons will be possible.
The first month I was on the General Surgery-White service, which is mostly gastrointestinal surgery. The second month I was on the transplant service, with a one-week stint on the neurosurgery service. The transplant service was the most enjoyable because the professors and fellows spent a significant amount of time teaching medical students. We were also required to make a 15-minute presentation on a topic in transplant; I did mine on organ sales. Some of the surgeries I saw over the two months included laparoscopic cholecystectomy, liver resection, Frey procedure for chronic pancreatitis, bowel resection, peritoneal window for a lymphocele, nephrectomy, and kidney transplant. Unfortunately I missed out on a liver transplant and Whipple procedure for pancreatic/bile duct cancer, which are big operations also performed on the services I rotated on. Overall I had a great time on surgery, but I don't think my skill set or scientific interests are aligned with a career in surgery.
While on neurosurgery, I saw several procedures on the spine as well as a temporal lobectomy for epilepsy. I wondered what sorts of surgery are available for epilepsy, how often it is performed, and how successful it is. Below is some interesting information I found.
Surgery is considered for epilepsy patients who have not responded to sufficient trials of anti-epileptic drugs (AEDs) and who have a reasonable chance of benefiting from surgery. What is considered "sufficient trials" is not set in stone, as an estimated 300 years would be required to try all AEDs in all combinations. Patients who benefit from surgery have what are called "complex partial" seizures, which means that their seizures originate in a defined focus in the brain and cause them to lose consciousness.
Before surgery, a number of tests must be performed. A brain MRI is taken to assess brain structure. An electroencephalogram (EEG) is commonly used to diagnose epilepsy but is usually not used to make major surgical decisions. Neuropsychological testing can determine the patient's baseline attention, concentration, language, visuospatial skills, verbal and visual memory, problem solving, personality, and emotional functioning. Many of these skills are carried out by distinct regions of the brain, so a patient's performance on the tests can tell physicians where the epileptogenic focus lies. The intracarotid amobarbital (Wada) test, in which the left and right sides of the brain are anesthetized one at a time, permits determination of language and memory lateralization. If a patient can accurately recall 75% of items presented during anesthetization, then the hemisphere contralateral to the one anesthetized should be able to support memory after the anesthetized hemisphere undergoes surgery. If the above non-invasive methods still leave ambiguities in the surgical plan, then invasive intracranial monitoring can be performed by placing electrodes in the space under the dura mater, the connective tissue sheath surrounding the brain.
There are four operations that can be performed for epilepsy:
1. Anteromedial temporal resection (AMTR): Excision of the amygdala (fear conditioning), hippocampal head and body (memory), uncus, entorhinal region (spatial memories), and the parahippocampal gyrus (memory encoding), and a variable portion of the tip of the temporal lobe. This is the most commonly performed procedure for epilepsy, as the medial temporal lobe is a common location of epileptogenic foci.
2) Corpus callosotomy: Disconnection of communication between the two brain hemispheres. Usually only the anterior portion of the connection wires are broken.
3) Functional hemispherectomy: One side of the brain is disconnected from all other structures, but the brain remains in place (actually removing one side of the brain increases morbidity).
4) Multiple subpial transection: Cuts are made perpendicular to the brain surface in the epileptogenic focus. The idea is that the cuts will disrupt side-to-side connections between neurons that cause a seizure to spread, while preserving connections from the outer most layer of the brain to the inner layers.
A 2011 study showed that in a cohort of 615 adults who underwent epilepsy surgery, 52% remained seizure-free five years post-op (excluding small seizures that did not cause the patient to lose consciousness). Patients with medial temporal lobe epilepsy can benefit from AMTR early in their disease course, even though the average waiting period for patients to undergo epilepsy surgery is currently 20 years. Corpus callosotomy usually decreases but does not stop seizures, as more than 80% of patients experience a 60-70% decrease in seizures (but 10-15% of patients get no benefit). Amazingly, cutting off communication between the brain hemispheres has remarkably few side effects. Occasionally patients have transient paralysis in part of their body or temporary bladder incontinence. While psychological studies can detect impaired inter-hemisphere communication, this does not interfere with patients' daily living. Similarly, functional hemispherectomy has a seizure-free outcome in 54-90% of patients, with the only common long-term complication being impaired motor function of the contralateral hand.
One more detail to add from the temporal lobectomy that I witnessed: rather than remove brain tissue en bloc, the surgeons used a suction device. Brain tissue was sucked up by the sucker, which made a horrible noise, and sent to waste!
In the future, I wonder if epilepsy surgeons will not be removing brain tissue, but possibly modifying it by injecting drugs or stem cells that would stabilize the electrical activity? Unfortunately we don't know how most epilepsy drugs work (hence the trial and error in selection and dosing), but if we figure that out, perhaps more targeted therapies carried out by surgeons will be possible.
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