Post on 03-Apr-2018
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Minimally Invasive Surgery
Minimally Invasive Surgery (MIS) is not just about small incisions but a true revolutionin the management of patients through surgical interventions.
The introduction of laparoscopic cholecystectomy in the late 1980s has become a newlandmark in the history of surgery. Since then, we have embarked in the quest for
techniques and materials to carry out all forms of surgery through smaller and smaller
incisions. MIS is performed with long instruments and video cameras placed through
small port sites in different parts of the body. This can be accomplished by directmanipulation of the instruments and the camera by the surgeon or even remotely through
robotic arms directed from a console within the operating room.
In 10 years MIS not only has changed techniques quite radically but also has madesurgery much safer. Safety has been accomplished by better exposure through perfected
optics, better hemostasis through various techniques and a high degree of versatility inthe possible tactics to be applied to handle the variants often encountered at surgery.
One early objection to MIS has been the potential of making surgery riskier by
lengthening the operating time. Long before MIS the risk of surgery was significantlyreduced by improved anesthesia techniques. The safety of anesthesia reached a point
where there was no longer a need to hurry through an operation. In fact, nowadays, the
morbidity of an operation can potentially increase if hurrying results in increased blood
loss. As independent variables, blood loss is a much stronger predictor of postoperativecomplications than operating time. Furthermore, blood loss usually extends the operating
time and this defeats the purpose of hurrying in the first place. As long as blood loss iskept to a minimum lengthening of an operation does not add risk to the patient. On theother hand the field magnification used in MIS has lowered the threshold for tolerance of
bleeding. As small a bleeding source may seem it is always controlled before it can
interfere with proper visualization of the field. Consequently, blood loss has beensignificantly reduced for every MIS procedure in comparison to the open counterpart.
Along with smaller incisions we have observed patients recover much faster and with
much less pain. In doing so, we also realized that other interventions we did aroundsurgery were as invasive, and painful, as the incision itself. Tubes places in the bladder
(Foley catheters) and stomach (nasogastric or NGT) have been used routinely in most
forms of surgery. Nowadays, they are used very selectively, placed only after the patientis under anesthesia and often removed before the anesthesia is reversed.
With the reduced blood loss there is less of a need for blood transfusion and blood workto monitor red cell counts. Less incisional pain results in less need for narcotic analgesics
which in turn allows for earlier mobilization of the patient and earlier return to full
function of all body systems: respiratory, urinary, musculoskeletal and, in particular,
gastrointestinal; thus eliminating the need for multiple tubes in the postoperative period,
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such as urinary catheters (Foley), nasogastric (NGT), drains (Jackson-Pratt and alike). In
the pre-MIS era the anxiety of the surgeon waiting for the return of bowel function often
led to obtaining imaging and laboratory studies which added more invasiveness and riskto the patient. The post-MIS area is also anxiety-producing for the nurses and surgeons
caring for the patient: we have lost some indicators for monitoring possible, albeit
unlikely, complications during recovery: hourly urinary output (measured through aurinary catheter), nasogastric output, and various measurements in blood. We are also
breaking some dogmas: patients go home before consuming a solid meal or having a
bowel movement after bowel surgery.
MIS has lead to a reduction in the length of stay in the hospital and of the length of
recovery at home. We are still informing patients that there is always the possibility of
having to resort to the traditional open approach and that by doing so the hospital stayand recovery time can be extended. A very interesting observation we are now making is
that when MIS is not feasible, or is not even tried at all, and the patient receives the same
minimalist postoperative management the hospital stay and recovery time is similar to
that of patients undergoing MIS. Therefore, incision and postoperative management canindependently reduce length of stay and recovery time if applied under the minimalist
concept. One dilemma for patients after MIS is the return to work. Those who workindependently are happy to be back in a week or less. Some of those who are entitled to
medical leave are disappointed when they realize that they cannot take as much time off
as some workers who had surgery for the same disease through the conventional, openmethod.
The minimalism in incision, and invasiveness before and after surgery, should not
be misinterpreted as a minimization of the risks of surgery. Under electivecircumstances, modern diagnostics allow us to detect, and correct, many disturbances of
the functioning of vital organs prior to surgery, thus reducing risk. We can optimize heart
function through medications and even interventions on the coronary arteries. In mostcases, we can also ensure that lungs and kidneys are able to sustain the stress of surgery.
However, there is a limit to the sensitivity of these diagnostic modalities and to the
efficacy of all these preoperative interventions, especially when we are performingsurgery in patients who are reaching unprecedented ages for surgery. In addition, there
are many factors that are still out of our control as surgeons: we can make a plan based on
experience and all the studies on a particular patient and find during surgery that such
plan is not executable. For instance there are many variants in the anatomy of bloodvessels; an operation, which is ordinarily very safe in the typical configuration of blood
vessels. Due to anatomic variations, unexpected or additional findings, or incidents that
occur with surgery (unusual bleeding, spillage of infectious material), the scope ofsurgery may escalate beyond MIS. While patients have always being informed about
these possibilities it seems that in this MIS era it comes as a surprise when surgery has
been extended due to intraoperative findings or occurrences.
Recent studies have given the green light for surgeons to apply MIS for cancer surgery in
the abdomen and chest. Earlier studies had raised concerns about the completeness of
cancer surgery through small incisions and the risk of implanting tumor cells in the
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incision through which the specimen is extracted. Neither one of these concerns has
proven valid; in fact preliminary data is showing better outcome in patients with cancer
who undergo MIS versus traditional open approach. Scientists are now trying to explainthis opposite and beneficial effect of MIS on cancer surgery. One possible explanation is
that proportional to the invasiveness of the surgery there is a immunosuppressive
response by the body, as if all the immune system is devoted to healing and establishing abarrier against infection losing its natural ability for cancer surveillance.
One problem we still struggle with when using MIS is the loss of tactile function. Thishas heightened the need for gathering as much information as possible before surgery.
Imaging studies, such as CT scan and MRI, can give us precision in location and
characteristics of the problem. Endoscopies with tattooing of the lesion are essential in
the gastrointestinal tract. One solution already in the works is bringing to the operatingroom with imaging and endoscopic equipment to further minimize the invasiveness to the
patient by doing this assessment in the same setting where surgery is to be done. Another
solution currently applied for bowel surgery is the ability to introduce a hand in the
abdomen while maintaining the incision sealed from gas leakage. In the case of bowelsurgery this has come as solution to various problems: in addition to affording tactile
function it allows extracting bulky specimens while protecting the incision fromimplantation of cancer cells.