Neurological Surgery
I also have been working on my clinical research project evaluating effectiveness of two different treatments for aneurysms, and have obtained some interesting results. I will be presenting my research project in the seminar meeting in
Overall, I gained a lot from this experience, especially in terms of realizing that there are many areas that still need technological improvements. I would like to thank my clinician mentor, Dr. Riina, and also Dr. Gobin and Dr. Chapple.
Finally, I convinced myself to watch at least one open heart surgery. I was surprised at how invasive the whole procedure was. The doctors’ basically sedated the patient, sliced his chest open, and then pulled his ribs apart using their bare hands or a crude mechanical device. It was almost like watching a scene out of a movie with hygienic zombies in scrubs trying to carefully eat the victim’s heart. Okay, maybe that’s an exaggeration. What followed was a bit more impressive. They bypassed the patient’s arteries, immobilized the heart using high concentration of potassium chloride, and then made an incision in the heart in order to replace the mitral valve. The following picture is borrowed from its.med.yale.edu. It depicts a mitral valve replacement.
Apparently, this particular patient had mitral valve regurgitation. This was evident from his transesophogeal echocardiogram or the ultrasound measurements. One could see that the oxygenated blood that entered the left ventricle through the mitral valve periodically reentered the left atrium. In most cases, a patient’s valve is irreversibly compromised due to either ischemia, stenosis, or infection. These problems are usually onset due to coronary artery disease, age, or rheumatic fever, respectively. However, congenital defects are not rare.
In the patient’s case, the problem was caused by ischemia through coronary artery disease. As a result, the doctor had decided to replace his valve with a bovine valve - the reasons for choosing a bovine valve or a mechanical valve were explained previously by Dickinson. It seemed as though the stitching of the valve required great dexterity. One of the more skilled residents tried to stitch the valve but it seemed as though he could not make the more difficult 10-12 o’clock stitches. As a result, the primary surgeon took over and showed him how it should be done.
One could definitely make it easier for these doctors by developing an innovative device for sewing. In fact, I don’t really know why a big hospital like NYP still uses open heart surgery for such cases. There are hospitals that are performing these types of procedures percutaneously using the da Vinci surgical system. I think that’s the way to go. If not, the least one should do is make something that replaces the “needle and string.”
Generally, an incision is made around the nipple and the nipple is then removed and a new nipple relocation is added to raise the nipple site to fit with the new smaller breast. Tissue is removed along with skin and then brought in downward to close over and shape the new breast. Scars will remain around the nipple, extended to the crease, and through the crease as seen in the pictures. Later that day, a patient came to office hours to be consulted for a breast reduction. Mistakes were also discussed where the reduction produced breasts that were very asymmetric and occasionally with nipples that were misplaced. Many of these complications arise because the doctor works with an assistant on one side or because of shifts from laying on teh operating bed to getting up. This really brought the talk together because I went from the academic discussion to the patient doctor interactions. During this week I was able to observe a few more surgeries and attend a few more rounds. I was luckily able to scrub into another tracheaesophageal fistula. The patient was two days old and had a type C fistula which consists of an upper esophagus ending in a blind pouch and a connection between trachea and fistula. Dr. Spigland was able to occlude the fistula and connect the esophagus back together.
However, during the esophageoesophagus connection the patient’s lung did not infant. The lung appear very deflated and small. A code blue was called and within 1-2 minutes a barrage of nurses, residents, and attendings came to help out. They ran into the room with concern expressions and eagerness to help out. The attendees quickly got the patient to start breathing again using manual ventilation. There was a pediatric cart in the room in case the use of a defiberator was needed. In actuality, most of the people who rushed in for the code blue just stood around watching while 1-2 attendees did all the work. But it’s a good sign when over a dozen people rush into the room minutes after a code was called.
I was able to make progress on my research and conclude some aspects of the project. I will continue to collaborate with Dr. Spigland on the research project dealing with esophageal atresia and hopefully write something up in the near future.
Maybe it is better in a certain way that I will not be collecting scores using VCAR. According to my mentor, although the software is more advanced than Smart Score, it is just as tedious to use. If you recall, the Smart Score software forced one to highlight the calcium in transverse CTA slices. It, thereby, was able to deduce a calcium score based on just volume (volumetric score) or area and average Hounsfield value (agatson number) for the overall calcium in the arteries. VCAR calculates the score in a similar fashion, but it does not need the user to highlight the calcium. Instead, it is designed to automatically segment the calcium in the arteries. However, before the algorithm is capable of doing this, one must click along the centerline of an artery so that the algorithm can basically fit a curve to the selected points and subsequently subtract it from the image to straighten out the artery. Then it presents the artery of interest in a longitudinal format so that one is better able to view the calcium deposits (figure). I’m not certain why this step is necessary. Nevertheless, the software seems very user friendly so I think it would have been fun to work with.
I was able to go to NICU (neonatal ICU) rounds this past week. Unlike neurological surgery rounds, which only last about 30 minutes, the NICU rounds lasted more than 2 hours. The two were quite different not only because of the age of patients, but also it seemed that in the NICU, rounds were focused on determining the day’s treatment for the patient as well as assessing each patient’s day to day progress, whereas in neurological surgery rounds were focused on just assessing progress. The cases in the NICU were striking in demonstrating the fragility of life, and how important treatment in the beginning of life is.
Neurological Surgery
One surgical procedure I observed this week which was particularly interesting was an endoscopic resection of a colloid cyst. First, some definitions are needed – a colloid cyst is a slow-growing non-malignant tumor that is usually located in the third ventricle of the brain. The cysts are composed of a cell layer on the outside of the cyst and a creamy-like colloid in the center. The colloid cyst can block drainage of the cerebrospinal fluid (CSF) and cause hydrocephalus.
MRI image of colloid cyst in the third ventricle. http://neurosurgery.ucla.edu
The treatment options for a colloid cyst include putting in a shunt to drain the CSF or surgery to remove the cyst. Surgery can either be done by a craniotomy or through the less invasive endoscopic technique that I observed. The endoscopic resection technique involves drilling a small centimeter diameter burr hole in the skull, then putting an endoscope with a camera through the hole (see picture). The cyst location is constantly irrigated from outside to maintain a clear view. Several small instruments are guided through the tubes in the endoscope to cut and burn the tissue. Then, several holes are made in the cyst cell wall. A suction catheter is used to suck away the colloid material from the cyst. A balloon catheter is inserted inside the cyst and inflated. The catheter is removed, taking cyst wall material with it. At the end of the procedure, the doctor then uses the bipolars to burn any remaining cyst which may not have been removed. I found the suction procedure quite interesting because sometimes, the doctor would start to suck non-colloidal material into the suction tube, and then would immediately stop the suction. It seems that it would be quite easy to make mistakes with this technique if the doctor is not well-trained, which is why this procedure is only performed at select hospitals.
Image of an endoscope passing through a burr hole in the skull. http://neurosurgery.ucla.edu
Colloid cyst viewed through an endoscope. http://neurosurgery.ucla.edu
The depth of the wound has decreased dramatically to about .5" deep. It is interesting to me that with a simple V.A.C. dressing the body is able to close over such a large open wound by itself. This week I helped in changing the V.A.C. dressing. First, we remove the old dressing and Dr. Spector cuts out in dead tissue as this will not help in wound closure. After debriding the wound, we place gauze in the wound and soak with Dakin's Solution. This is a aseptic solution for cleaning wounds what is made of sodium hypochlorite and boric acid (4 %). We allow the patient to sit our the 'rinse cycle' for a few minutes while the wound is soaked in Dakin's. Then we remove the soaked gauze and dry off the wound. The standard oval shaped black sponge is then cut to fit the wound. Often the doctor will cut the sponge half thickness and then cut out the pattern of the wound. This helps to keep the healthy tissue surrounding the wound health and increase drainage from the wound while promoting the granulation of the wound bed. A picture (from www.kci.com) is shown that pictorially shows how the fluid in the wound bed is able to exit through the black sponge and the vacuum is able to help in wound closure. Now that the patient has seen the wound closure capabilities of the V.A.C. and the wound has greatly decreased in size, there are now other options for closure of the wound. Because the patient has also lost weight over this time period, it may be possible to simply elevate the tissue on either side and close the wound. By leaving the V.A.C. on for a few more weeks, this would certainly be possible. It would also be possible, to put a skin graft over the wound to close it. As of now, the patient has opted to keep the V.A.C. dressing on and continue to allow the wound to make progress this way.
With the first option, the procedure is called a free flap where tissue is taken from one part of the body and used in another, but it is moved with its own blood supply and hooked into the blood supply around the new site. For the tissue expander, the expander is placed under the muscle and slowly expanded by adding saline ever few weeks until the desired size is reached. Once the size is correct, implants are placed. In either case, addition surgery is required to reconstruct the nipple. In the OR, first the breast team comes in and removes the cancerous breast. The day prior to the surgery, the patient is injected with a dye which then accumulates in the nodes, which can easily be seen during surgery. An incision is made around the areola and then the skin is elevated off of the underlying breast tissue. The nipple and breast tissue are then removed. The nodes are then removed and sent to pathology. Frozen sections are taken and the surgery team is informed whether the cancer is present in the nodes. The sentinel lymph node is specifically checked. This is an indication as to whether the cancer has spread to other parts of the body. Once the breast team has finished, the plastics people come to the OR and begin the reconstruction. The tissue expander is placed under the muscle with a small amount of saline in it. For the next few months the patient will come in periodically to have more saline injected into the expander. The port on the expander is labeled with a magnet so that Dr. Spector can use a magnet externally to locate the port.
This week I have a chance to observe Dr. Milson performs a laparoscopic surgery. When I entered the operation room, the surgery is already started. Everyone was pretty relaxed. The patient was lying on the operating table “sounds asleep”, while Dr. Milson was cracking joke and directing the residents what to do. When I walked close to the operating table, I saw there were various long rod-shaped surgical tools sticking from the abdomen of the patient’s body. Three physicians were holding these various surgical tools and watching the screen in front of them. One thing stand out is that the patient’s abdomen is swell like a balloon. Later I found out that in this kind of laparoscopic surgery, the abdomen is usually inflated with CO2, so the physicians have more room to work with. When I looked up at the screen, u can see all the guts of the patient. Also u can see the ends of the long surgical tools. Several of them are small clamps that use to hold different tissues. One scissor shaped tool is use to cut the connective tissue away from the sigmoid colon. It not only function as a scissor, but has some kind of heating mechanism that will seal the wound from the cutting so not much blood came out. It was quite amazing to see that how three physicians can work cooperatively to remove all the connected tissues from the sigmoid colon. Since it is already hard to maneuver using these long tools, and two people have to hold the tissue in place, so the other physician and cut them away from the colon. After the sigmoid colon is completely remove from the rest of the connective tissue, the doctor took the whole thing out from one of the incision of the body, and cut away the disease part. Then he used a special stable gun to join back the colon and the rectum. Finally, one of the residents performed a leak test to assure the colons are joined completely.
The whole procedure took about an hour and half, which is longer compared to traditional open surgery. However, there are several advantages. First, since only several small incisions are made during surgery, the recovery time will be shorter. Furthermore, blood loss will be minimal. One thing is quite remarkable in this type of surgery is the design of these various surgical tools used in the surgery.
This week I went to electrophysiology (EP) lab in cardiology. In this laboratory, I mainly observed two procedures: implantation of a artificial pacemaker and Electrophysiology study.
The artificial pacemaker is a programmable device that generates electrical impulse to the heart to regular heart beats. The electrical signal is delivered by electrodes contacting the heart muscles. Usually people need a pacemaker when their own natural pacemaker is not working properly. When I first entered the EP Lab, they made me wear this 60 pounds lead to prevent radiation from the x-ray. It is quite tiring even wearing it for an hour, I must say quite admired these doctors are able to wear them all day long and perform operations.
The procedure itself is actually quite simple. The physician made a small incision on the right side of the upper chest, and then he threaded two special wires (in which the proximal tip contains an electrode) into the body and place the electrode near the heart muscle. Then he asked the assistant to generate different electrode signals through the wires and watch the pattern on the ECG. Then he adjusted the placement of the wires and repeated the signal generation several time till he got the desired ECG signals he wanted. Finally, he obtained a pacemaker and connected the wires into it and put the small device near the incision area. Then he secured the device under the skin and sewed up the wound. After the implantation is done, the physician went to a computer and remotely programmed the device.
From talking with the physician, I found out that these peacemakers generally last 5 to 10 years depending on the condition of the patient. Some patients like the one he just operated on only require pacing at certain time, but some other patients require the artificial pacemaker to work all the time.
The second type of procedure is an electrophysiology (EP) study. Normally, electricity flows throughout the atria first and then pause for a moment before the electric signal is propagate to the ventricles through the atria-ventricular (AV) node. The electrical signal brings about heart muscle contraction. The orderly pattern guarantees that the heart pumps blood efficiently. Whenever something wrong along the electrical conduction system, it causes a heart rhythm disturbance (termed arrhythmia), which will leads to inefficient pumping of the blood out to the body. The reason for an EP study is to find out the cause of such arrhythmia. Usually during an EP study, wires are placed on the sinus node (natural pacemaker), one on the AV node and one on the bundle of His (which is the wire that sends signal from AV node to the rest of ventricles). They also place several wires on the ventricles and atriums depending on situation. Then they will generate electrical signal on different places, and observed the corresponding signal recorded elsewhere to try to figure out the cause of the arrhythmia.
Vascular Surgery
Week 6
Vascular Research Project
My research project looks at the outcomes of vascular procedures in women. My surgeon mentor and others think that there may be a relationship between the outcomes of vascular procedures and hormone replacement therapy (HRT), osteoporosis, and menopause. “Outcome” is defined as patency—that is whether or not a vessel is open at a follow-up visit after surgery. After writing a script that was approved by the surgeons in charge, I called a list of about 300 elderly female patients (average age = 76) to ask them about HRT, osteoporosis, and menopause. Awesome!
The Patients
Some women were surprisingly sharp and inquisitive and really opened up to me over the phone. The responses were understandably colorful—if the patient felt better they exalted their surgeon while some patients with poor outcomes told me they had found new surgeons and hospitals entirely. Often the same surgeon was regarded in both positive and negative ways. This is understandable considering the variable difficulty in treatment that occurs between patients and procedures.
One thing that surprised me was that patients were very willing to open up to me over the phone—I heard some fascinating life stories. Alternatively some patients would not talk to me at all—they didn’t trust that I was calling from New York Presbyterian Hospital and requested a written questionnaire while others could only speak in Spanish. Other difficulties like disconnected telephone numbers and no answers left the respondents to about 30%. From these patients I got some interesting data regarding patency, HRT, and osteoporosis—really interesting data…that I can’t show you here because it might get published! Stay Tuned!
The second question is how to connect the remaining part to the anal control muscle. This is more complicated. The End-to-End Anastomosis device has a detachable anvil at the distal end. To operate, the surgeon needs to put the anvil inside the remaining intestine and the EEA through the anus. Since both the anvil and EEA device have pointed piercing structure, they can connect to each other. After they are connected, squeeze the trigger to make a circular cut and anastomosis at the same time. Therefore, the remaining intestine is safely connected to the control muscle. After pull the entire device out from the anus, this step is finished.
