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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_917_Библиотеки_им_академика_М_И_Перельмана.pdf
378
Scope warmer
S. Marecik et al.
Robotic cart
Vision cart
Tray
Assistant
Anesthesiologist
Fig. 24.3 Robotic cart positioning
The X system utilizes the Xi system ports and instruments, but the port placement
can be chosen between Si and Xi.
Extraction Site
The preferred extraction site is a Pfannenstiel incision for cosmetic reasons and an
extremely low hernia formation rate [20]. Alternatively, the specimen can be
extracted through the ileostomy site. In this case, the incision would likely have to
be enlarged at the skin and fascial levels for the larger specimens. This could
increase the risk of stomal prolapse and/or parastomal hernia. Select patients can
undergo transanal or transvaginal specimen extraction, particularly when handsewn anastomosis follows the pull-through procedure [21].
Operative Technique: Surgical Steps
After safely establishing the pneumoperitoneum, diagnostic laparoscopy is carried
out to conrm the appropriateness of the planned resection, including plans for
splenic exure release and use of a hybrid or fully robotic technique.
24 Robotic Low Anterior Resection: Unique Considerations andOptimal Setup
379
Exposure of the base of the left colon mesentery and the sacral promontory is
obtained by adjusting the table tilt and sweeping of the small bowel to the right and
upper abdomen. All necessary ports are then placed, the robot docked, and the
instruments inserted under direct vision.
A decision is made regarding where to initiate the dissection and the sequence of
dissection. Most surgeons prefer a medial to lateral approach for mesenteric dissection. However, the surgeon should be familiar with the lateral to medial approach if
exposure of the base of the mesentery is complicated by severe visceral obesity or
inability to sweep away small bowel loops, uncertainty regarding the anatomy,
aneurysmal aorta, suspiciously enlarged lymph nodes, or extensive scarring or
inammation. The medial to lateral approach can be initiated by incising below the
IMV, above or below the IMA, or at the level of the sacral promontory. Likewise,
the splenic exure can be mobilized using a lateral to medial, supra-mesocolic or
infra-mesocolic approach.
Mesenteric Dissection andIMA Ligation
When starting the dissection below the IMV or above the IMA, the peritoneal
incision should be initiated between the vein and a distinct autonomic (sympathetic)
nerve running along the left side of the aortic surface. This nerve, which serves as a
very helpful anatomical landmark, eventually joins the (peri) IMA nerve plexus.
Aproper initial incision guarantees easiest access to the correct plane within lamellar Toldt’s fascia, between the retroperitoneal and the mesocolic fascia [22].
Squiggly vessels of Toldt’s fascia, left on the mesocolic side of the dissection, indicate that the dissection was carried out too deep. Small oozing from these vessels
can eventually stain the dissection plane. A proper (non-bloody) dissection plane
should keep the squiggly vessels on the retroperitoneal side.
When the dissection is initiated below the IMA, it is more difcult to nd the
proper plane (Toldt’s fascia). This almost always leads to dissection in the deeper
plane, below the retroperitoneal fascia. The main reason for this difculty is the
presence of a distinct autonomic nerve layer in front of the aorta, in addition to often
seen brosis, inammation, and sometimes lymphadenopathy between the IMA
and the aorta. The main consequence of too deep of a dissection is oozing from the
small vessels and potential injury to the ureter and the gonadal vessels.
For the reasons stated above, the dissection is frequently initiated at the level of
the sacral promontory. This is done by retracting the rectosigmoid, with the far-left
instrument stretching the peritoneum at the base of the rectosigmoid. Hot dissection
also helps in plane identication between the mesentery and the prehypogastric
nerve fascia (pHGNF). The latter is a fascial layer covering the superior hypogastric
plexus (below the aortic bifurcation), both hypogastric nerves, and the sacral
splanchnic nerves (SSN) deeper in the pelvis (Fig.24.4) [23]. The pHGNF must be
kept intact in order to minimize injury to these important autonomic nerves.
Dissection is continued cephalad along and above the nerves and pHGNF layer,
toward the root of the IMA, avoiding further lateral dissection. A helpful maneuver
380
Fig. 24.4 Prehypogastric
nerve fascia (pHGNF)
covering the superior
hypogastric plexus and
both hypogastric nerves.
The fascia was incised
between both diverging
nerves, and the plane of
dissection was changed,
leaving the pHGNF
attached to the mesorectum
S. Marecik et al.
at this point involves moving the dissection above the IMA.This helps to establish
a proper layer of easily identiable Toldt’s fascia above (cephalad from) the IMA.In
addition, “connecting the dots” between the planes above and below (cephalad and
caudal of) the IMA helps prevent violation of the retroperitoneal fascia along the
entire length of dissection. Thus, if the retroperitoneal fascia remains intact in a
bloodless operating eld, the left ureter and gonadal vessels will also be left intact
below the fascia, and a search for the ureter by dissection through the retroperitoneal fascia will not be necessary. Conversely, if the operating eld becomes bloody
and/or the retroperitoneal fascia is violated, the ureter must be clearly identied.
Dissection continues at the root of the IMA, where it is circumferentially
dissected, isolated, and then divided. Several methods can be used, including the
laparoscopic or robotic clip applier (most cost effective), a robotic vessel sealer, a
vascular stapler, or a laparoscopic bipolar energy device. The dissection is then
carried from the medial to the lateral aspect by dissecting between the retroperitoneal and mesocolic fascia. One of the robotic arms, usually the far-left one, provides
a macroretraction to the detached mesenteric base and should be continually
adjusted to provide adequate tension during medial to lateral dissection. The dissection is extended onto the white line of Toldt. Any difculty encountered during
medial to lateral dissection, such as difculties identifying the correct plane or the
left ureter, can be circumnavigated by changing the dissection to the lateral to
medial approach. When the lateral to medial dissection is performed, the far-left
robotic arm is applied laterally to the white line of Toldt. The other retracting arm
provides the medial microretraction on the bowel and mesentery.
Splenic Flexure Release
The various strategies for laparoscopic splenic exure release (SFR) are described
in the Masters chapter (Chap. 4) on laparoscopic SFR, tips and tricks. Robotic surgeons should be familiar with the lateral to medial, supra-mesocolic or inframesocolic approach, in case difculties arise and an alternative approach is needed.
24 Robotic Low Anterior Resection: Unique Considerations andOptimal Setup
381
Several techniques of splenic exure mobilization have been described for both the
Si and Xi systems [14, 15, 24]. While it is possible to mobilize the exure and perform the TME with one robotic setup, the Si system techniques are generally more
demanding. They frequently require arm repositioning and/or system redocking and
may be achieved easier with the hybrid (laparoscopic) approach. On the other hand,
the design of the Xi system allows for less external arm collisions and better reach.
When combined with integrated table motion and appropriate port placement, it
allows for more effective one port setup for splenic exure mobilization as well as
for rectal dissection. Also as mentioned, the in-line port setup must be done in a
more vertical fashion, thus opening a more effective angle for the splenic exure.
Alternatively, a completely horizontal, mid-abdominal robotic port placement can
effectively serve the splenic exure and pelvis, following boom rotation and instrument exchange.
Rectal Mobilization
This part of the dissection is fairly standardized and very reproducible with repetitive
movements, particularly when compared with splenic exure mobilization. The
objective of successful TME is to perform a gradual release of the mesorectum
(posterior, anterior, and both lateral) using effective and atraumatic retraction of the
mesorectal specimen.
Posterior Dissection
The rectum is mobilized posteriorly to the level of the lower sacrum. During the
upper part of the dissection, care should be taken to preserve the pHGNF (the innermost layer of the presacral (Waldeyer’s fascia). The pHGNF covers the superior
hypogastric plexus, the right and left hypogastric nerves, and a signicant portion of
the sacral splanchnic nerves), all of which are important as safety landmarks and are
essential for both sexual and urinary function (Fig.24.5). Additionally, because the
Fig. 24.5 Sacral
splanchnic nerves (SSN)
originating from the pelvic
sympathetic trunks and
converging in the pelvic
plexus (seen in the left
upper corner); pHGNF
lifted with the mesorectum
382
Fig. 24.6 Retraction of
the mesorectum during
posterior dissection, left
hand grasper with
90-degree wrist angulation
S. Marecik et al.
posterior avascular plane can be easily identied, it is often advantageous to continue this plane of dissection around the rectum, mobilizing the mesorectum from
the right and left lateral pelvic compartments. In order to provide the best exposure,
the far- left robotic arm with Cadiere forceps is used to provide a macroretraction
to the rectum in the cephalad and anterior direction. The medial left robotic arm
with the fenestrated bipolar grasper is then used to provide a gentle microretraction
on the mesorectum, close to the area of hook/scissors dissection (performed with
the right arm). In experienced hands, using the wrist of the instrument at a 90-degree
angle to the shaft, the macro-retracting arm can frequently lift and support the
mesorectum without actually grasping it (Fig.24.6). Posterior TME dissection proceeds either between the mesorectal fascia and the pHGNF (with reduced risk of
injury to the nerves) or between the pHGNF and the nerves, which exposes the
nerves but may extend the posterior resection margin in cases where the mesorectal
fascia is threatened by tumor. It is the authors’ preference to preserve the pHGNF
until a clear divergence of the two hypogastric nerves can be seen toward both pelvic sidewalls. At that point, the pHGNF is routinely incised, and dissection falls into
the plane between the pHGNF and the sacral splanchnic nerves (Fig.24.4).
Another implication of precise and bloodless surgery is the ability to visualize
anatomical landmarks to guide the dissection. This is important in the case of
unclear anatomy due to inammation, tumor, previous radiation, or previous dissection. While it is rare to visualize SSN during open surgery, they are easily identied
during robotic surgery and should be preserved (Fig.24.5).
It is also important to point out that many general surgery and colorectal textbooks
describe Waldeyer’s fascia as a structure penetrating the mesorectum and spreading
between the sacrum and the rectal tube. It is often referred to as “rectosacral” or
“retrosacral.” In fact, the presacral Waldeyer’s fascia has two components, with a
more posterior one covering the presacral vessels and a more supercial one
covering the hypogastric and sacral splanchnic nerves. The name of the latter layer
is the pHGNF (prehypogastric nerve fascia). Waldeyer’s fascia spreads onto the
lateral aspects of the mesorectal compartment, where it ultimately embeds the pelvic (inferior hypogastric) plexi (Fig.24.7).
24 Robotic Low Anterior Resection: Unique Considerations andOptimal Setup
Fig. 24.7 Pelvic fasciae and nerve structures. (Used with permission of Wolters Kluwer from
Marecik etal. [25])
Fig. 24.8 Dissection
through the left lateral
tethered surface; left
hypogastric nerve
converging with the sacral
splanchnic nerves to form
left pelvic plexus;
mesorectum– bottom/right
383
Lateral Dissection
The area of the lateral rectal attachments (stalks) is referred to by authors as
“lateral tethered surface” and not “lateral ligament.” These are often taken down
by cautery and sharp dissection (Fig.24.8). When most of the lateral mobilization is completed as a continuum of the posterior dissection around the rectum,
this part of the dissection is relatively easy, particularly if the line of anterior
dissection has been previously marked (Fig.24.9). Care should be taken, however,
384
Fig. 24.9 Dissection
through the left lateral
tethered surface; left edge
of Denonvilliers’ fascia
still attached to the
mesorectum; left pelvic
plexus visible laterally
S. Marecik et al.
not to injure the lateral pelvic plexi. This is where the sympathetic hypogastric
nerves and sacral splanchnic nerves converge with the parasympathetic sacral
pelvic nerves (knownas nervi erigentes, located in the posterior aspect of the
lateral compartment) (Fig. 24.7) [25]. The left lateral dissection is performed
with the far-left instrument retracting the lateral wall, the medial left instrument
pushing the mesorectum to the right, and the right-hand instrument crossing the
medial left instrument for dissection. The right lateral dissection is performed
with the far-left instrument retracting the mesorectum (macroretraction to the
left), while the medial left instrument pushes the right anterior Denonvilliers’
fascia (DF), or the lateral wall, while positioned in front of or behind the righthand dissecting instrument.
Anterior Dissection
The rectovaginal/rectovesical peritoneal fold is incised to expose the DF, and the
rectum is mobilized from the vagina/prostate. The key to avoiding potential
bleeding from the ne vascular plexus that surrounds the seminal vesicles or
posterior vaginal wall (venous sinuses) is to maintain the plane of dissection just
posterior to DF, unless the tumor is threatening it. This also helps to avoid injury
to the neurovascular bundles of the prostate (and vagina). These are covered by
the lower portion of DF just above the pubococcygeus levator muscle in the
anterolateral portion of the mesorectal compartment (Fig.24.10). The xed macroretraction provided by the far-left robotic arm on the bladder/prostate/vagina
facilitates surgical access and visualization during anterior rectal dissection,
while the micro-retracting arm pushes the mesorectum posteriorly (downward)
(Fig.24.11a, b). Of note, during a clean TME technique, the lateral edges of the
trapezoid-shaped DF can be seen covering the anterior half portion of the pelvic
plexus (Fig.24.12).
24 Robotic Low Anterior Resection: Unique Considerations andOptimal Setup
Fig. 24.10 Right anterior
dissection at the level of
the pubococcygeus levator
muscle; mesorectum on the
left, right neurovascular
prostatic bundle (“erigent
pillar”) above the cautery
hook, covered by
Denonvilliers’ fascia
385
Fig. 24.11 (a) Anterior
dissection, the macroretracting arm (top) is
retracting the anterior
pelvic structures (cephalad
and anterior direction). (b)
The micro-retracting arm
(left) pushing on the
mesorectum downwards
a
b
386
Fig. 24.12 Left edge of
Denonvilliers’ fascia;
mesorectum on the right
side, pelvic plexus visible
laterally
S. Marecik et al.
Pelvic Floor Dissection
This part of the dissection can be challenging because it is the most distal part of the
TME.Occasionally, the robotic ports need to be pushed in beyond the recommended
black mark on the cannula, in order to obtain adequate reach in tall patients. It is
also possible for the instrument wrists to start losing their responsiveness at times.
This requires resetting by simple removal and reinsertion. The exposure can also be
challenging in very obese patients with a narrow and muscular pelvis, as well as in
thin patients with a stretchy rectum and levators with their fascia. Finally, for low
rectal cancers, there is a narrow margin for error because of the converging pelvic
space and lack of mesorectal fat coverage.
The anterior mobilization is often easier during deep pelvic oor dissection due
to the shorter distance to reach the levators. Here, a small segment of the pubococcygeus muscle can be exposed posteriorly next to the base of the arcuate DF
(Fig.24.10). In fact, it is also easy to reach the levators in the lateral aspects, right
at the lateral edge of DF and medial to the pelvic plexus. This is where the domes of
the iliococcygeus muscles are located.
Medial dissection of the dome-like portion of the levators can be more difcult
due to the depth of dissection. In addition, the endopelvic fascia (levators’ fascia in
this case) becomes quite stretchy and often difcult to dissect from the stretchy
mesorectal fascia. Similarly, the posterior dissection of the pelvic oor, which starts
below the posterior impressions of the piriformis muscle (S4/5 level), with a at and
tendinous coccygeus muscle, will lead deeper into the levator “funnel,” along the
levators’ raphe, and toward the anorectal junction. These nuances, together with the
fact that posterior dissection requires signicantly more work than anterior dissection, may lead to difculty in determining at what level to stop the dissection for
adequate distal margin below the tumor. As a result, deep pelvic dissection may
require a 30-degree-up camera angulation.
24 Robotic Low Anterior Resection: Unique Considerations andOptimal Setup
387
Distal Mesorectal Clearance, Rectal Transection, andAnastomosis
Once the mesorectum is adequately mobilized, the distal transection site is prepared.
If the goal is to perform an ultralow anterior resection with a staple line on or close
to the anorectal junction, a circumferential clearance of the mesorectum or thickened
mesorectal fascia is usually simple due to the minimal amount of mesorectal tissue
at that level. For the more proximal stapler application, the mesorectum must be
transected rst. It is helpful to perform an intraoperative exible sigmoidoscopy to
conrm a tumor-specic transection site or, alternatively, one can rely on India ink
marking. Mesenteric transection can be easily performed using a cautery hook. It is
best to start in the right anterior aspect, where the rectal wall is subsequently
exposed. The dissection is gradually moved toward the posterior midline, exposing
more circumference of the rectal wall. The process is repeated on the left side,
establishing the rendezvous in the posterior midline. Large and bulky mesorectum
can be challenging, and care should be taken to transect the mesorectum on the
same level during the left- and right-sided division. Care should also be taken to
avoid the “spiral apple peel” effect, with unequally transected left and right side.
Depending on the level of transection, the macro-retracting far-left arm may need to
support the anterior pelvic structures for adequate exposure or to retract the specimen. The assistant’s instruments can be very helpful in supporting the exposure or
the specimen during this part of procedure.
Once the distal transection site is prepared, a linear and articulating robotic
stapler can be applied. The robotic stapler has smart clamp technology which makes
it more comfortable and easier to control than the laparoscopic instrument. It is
typically inserted through the right-hand port; however, the port itself needs to be
rst upgraded to a 12mm cannula. During the stapling process, the far-left robotic
arm provides a macroretraction to the anterior pelvic structures. Meanwhile, the
medial left arm stretches and attens the rectum for stapler application. The stapler
can be supplied with blue or green cartridges and is available in 30mm, 45mm, and
60 mm length. On average, at least two stapler applications are necessary for
successful rectal transection. The smart clamp technology allows for initial tissue
compression, active feedback, and stapler reapplication during this process, in order
to optimize the amount of tissue in the stapler jaws to the height of closing staples.
The proximal mesenteric transection in the sigmoid or descending colon can be
performed using a robotic or laparoscopic vessel sealer. The stapler is used to transect the bowel. Alternatively, the colon with a resected rectum can be exteriorized
for extracorporeal division and anvil application, including the transanal route.
A suprapubic horizontal incision and the ileostomy site are preferred extraction
sites. With experience, an intracorporal purse-string suture application and anvil
insertion can be performed after the staple line from the proximal colonic end is
removed. The anastomosis is performed in a standard fashion, with two left robotic
arms retracting the anterolateral walls of the mesorectal compartment, providing
excellent exposure. A double-stapled anastomosis can also be performed in the