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Master Program Colorectal Pathway:
Laparoscopic Splenic Flexure Release
(Tips andTricks)
AntonioCaycedo-Marulanda andJohnH.Marks
Introduction andRationale
Splenic exure release otherwise known as the mobilization splenic exure is an
essential skill for all general and colorectal surgeons who perform colonic resections. The fundamental benet of mobilizing the splenic exure is the construction
of a tension-free anastomosis following left colectomy, sigmoid colectomy, anterior
resection, low anterior resection, as well as total mesorectal resection resections
(TME) with coloanal anastomosis. Additionally, SFR is routinely performed during
total and subtotal colectomies.
The extra colonic length provided by SFR allows for the descending colon to
reach down into the deep pelvis for restoration of bowel continuity. While SFR may
be performed selectively by some, most surgeons routinely perform SFR for all leftsided colectomy to ensure an adequately perfused anastomosis without tension [1–
3]. Distance from the anal verge plays a signicant role as a risk factor for
anastomotic leak in colorectal anastomoses, with tumors located 6cm or less from
the anal verge being at the highest risk [4]. It is possible that when creating these
low colorectal or coloanal anastomoses, blood supply relies on the different connecting arcades, which may or may not be present, thus increasing the risk of leak
secondary to ischemia [5].
4
A. Caycedo-Marulanda
Health Sciences North, Department of General Surgery, Division of Colorectal Surgery,
Northern Ontario School of Medicine, Sudbury, ON, Canada
J. H. Marks (
Lankenau Medical Center, Department of Colon and Rectal Surgery, Wynnewood, PA, USA
e-mail: marksj@mlhs.org
© Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) 2020
P. Sylla et al. (eds.), The SAGES Manual of Colorectal Surgery,
https://doi.org/10.1007/978-3-030-24812-3_4
*)
45
46
A. Caycedo-Marulanda and J. H. Marks
Indications andContraindications
Indications include resections involving the left side such as left colectomy, sigmoid
colectomy, anterior resection, low anterior resection, ultralow anterior resection
(with coloanal anastomosis), and total abdominal colectomy. As a general principle,
colorectal anastomosis following sigmoid resection for diverticulitis or colon cancer should be performed to the rectum itself and not to the rectosigmoid, which
usually requires additional colon length for reach and hence SFR. Studies have
shown that the relapse rate is much higher for diverticulitis if the rectosigmoid and
distal sigmoid colon are left in place [6]. In addition, anastomotic integrity relies on
meticulous dissection, adequate blood supply, and lack of tension [1]; the last two
are optimized by performing SFR.When the decision to perform SFR is left to the
end rather than the start of the operation, it is usually fraught with more technical
difculties and usually results from poor preoperative planning.
In the current era, there is an increased interest in sphincter preservation and
restoration of bowel continuity [7]. Low and ultralow rectal cancer surgery has
become more prevalent, and newer approaches have been introduced, including the
use of robotic platforms and those for transanal total mesorectal excision (taTME)
[8–10]. In these cases, splenic exure release is mandatory if reconstruction is to
take place.
It is our opinion that SFR should be performed systematically and at the beginning of the case, particularly during sigmoid resection for diverticulitis, before any
difculties are encountered during pelvic dissection. SFR is also strongly recommended during TME with planned sphincter preservation for rectal cancer [11]. The
specic SFR approach used is based on the surgeon’s preference and patient’s anatomy. There are no absolute contraindications to performing SFR.It should be noted,
however, that in patients who have had previous gastric or left upper quadrant surgery as well as pancreatitis, the dissection might be more difcult.
Principles andQuality Benchmarks
The goal of this step in the operation is to return the left colon to its original embryologic state. The surgeon should be mindful of the fact that embryologically the
hindgut and distal midgut are midline structures. Originally, the bowel is extraabdominal and undergoes counter-clockwise rotation to be sealed to the lateral
attachments along the line of Toldt (Fig.4.1a–e). By fully releasing the mesentery
of the distal and transverse colon, the left colon is returned to its embryologic midline state (Fig.4.2). This is essential to allow for a tension-free anastomosis of the
descending colon to the rectum. It is helpful for the surgeon to picture this as separating the pages in a book, such that the mesentery leaf is freed from the next page,
which is the retroperitoneum.
bc
d e
4 Master Program Colorectal Pathway: Laparoscopic Splenic Flexure Release (Tips…
47
Fig. 4.1 (a–e) Embryonic
bowel rotation. The
embryologic bowel is
extra-abdominal and
undergoes counterclockwise rotation to be
sealed to the lateral
attachments along the line
of Toldt
Stage I
a
Gestation: 6 weeks
Stage II
Gestation: 8 weeks
Gestation: 11 weeks Gestation: 12 weeks
Gestation: 9 weeks
Stage III
48
Fig. 4.2 Full splenic
exure release. The release
of the mesentery of the
distal transverse colon and
the descending colon
returns the left colon to its
embryologic midline state
A. Caycedo-Marulanda and J. H. Marks
Perioperative Planning, Patient Workup, andOptimization
Patients undergoing SFR as part left-sided resection will undergo standard workup,
staging, and preoperative planning based on the actual diagnosis. Almost invariably, patients will undergo computed tomography scanning (CT) as part of their
workup. Additionally, a barium or gastrogran enema can be very helpful in demonstrating the conguration of the descending colon, the level and extent of diverticular disease, and may help with the decision-making related to extent of the
resection that may be needed. However, it is rarely the case that any imaging is
obtained for the sole reason of assessing the suitability of the splenic exure for
mobilization.
There is a lack of standardization of preoperative assessment of the blood supply
of the splenic exure, which has proven to have signicant variability. Different
recognizable patterns have been identied in a recent radiologic study, in which
preoperative blood supply was determined by using CT angiography and CT colonography with 3-D reconstructions. In this publication, 39.7% of the blood supply
was identied to originate from the left colic artery (LCA), 17.8% from the left
branch of the middle colic artery, 9.9% from the LCA and the left branch of the
middle colic artery, 4.2% from the accessory left colic artery, 2.6% from the LCA
and the accessory left colic artery, and 25.8% from the marginal artery [12]. These
newly classied patterns differ from the traditional belief that 85–89% of the blood
supply of the splenic exure originates from the left colic artery and 11–15% from
the left branch of the middle colic artery [13]. That being said, we know that the
descending colon and splenic exure are well supplied by vascular arcades originating from the middle colic vessels that connect with blood supply that comes from
the inferior mesenteric artery (Fig.4.3), and it is extremely rare that ligation of the
IMA proximal to the left colic results in frank ischemia in the left colon when the
proximal mesentery is uninjured.
Technology to assess the blood supply of the large bowel preoperatively is available [14]. There is no evidence, however, to indicate that patients have a decrease in
the rate of complications secondary to ischemia when they undergo preoperative
assessment of the blood supply compared with those patients who do not, and this
mesenter
mesenter
ry
4 Master Program Colorectal Pathway: Laparoscopic Splenic Flexure Release (Tips…
Artery of
drummond
Arc of riolan
Artery of
moskowitz
49
Superior
ic artery
Inferior
ic artery
Fig. 4.3 Vascular arcades connecting the middle colic vessels to the blood supply of the IMA
Left colic arte
does not play a role in routine preoperative planning for patients [15]. Please refer
to Chap. 29 on best practices to assess the integrity and perfusion of left-sided
anastomoses.
Operative Setup
The operative setup would be the same as for left-sided and pelvic procedures and/
or total abdominal colectomy. The optimal trocar position includes a 10–12mm
camera port through or near the umbilicus, a second 10–12mm port in the right
lower quadrant (main port for the left-sided dissection), a 5mm port in the lower
aspect of the right upper quadrant, close to the umbilicus, and a second 5mm port
on the contralateral side. The assistant should ideally stand either between the legs
or on the right side of the patient with the primary surgeon standing on the right side
during the SFR. The surgical table could either be on mild or full reverse
Trendelenburg position. This is optional and depends on the surgeon’s preference.
In our practice, the patient remains in Trendelenburg position throughout the SFR.
50
A. Caycedo-Marulanda and J. H. Marks
Operative Technique: Surgical Steps
The operative approaches for release of the splenic exure are well established and
should be performed in a standardized fashion. There are three options available to
the surgeon including the supramesocolic, the inframesocolic, and the lateral to
medial approach.
Supramesocolic Approach
The patient is placed in a reverse Trendelenburg roughly ve degrees, maximal right
side down. The camera is trans- or supraumbilical; the left hand is used to grasp the
gastrocolic ligament close to the stomach. Gravity allows for downward traction of
the transverse colon, putting the gastrocolic ligament on stretch (Fig.4.4). The right
hand coming from the right lower quadrant is utilized to identify rst and then incise
the perforating veins between the gastroepiploic veins on the greater curvature and
the transverse colon (Fig. 4.5). Once this space is entered, the lesser sac is
Fig. 4.4 Gastrocolic
ligament on stretch. The
camera is trans or
supraumbilical, the left
hand is used to grasp the
gastrocolic ligament close
to the stomach. Gravity
allows for downward
traction of the transverse
colon, putting the
gastrocolic ligament on
stretch
Fig. 4.5 Gastroepiploic
vein. The right hand
coming from the right
lower quadrant is utilized
to identify rst and then
incise the perforating veins
between the gastroepiploic
veins on the greater
curvature and the
transverse colon
4 Master Program Colorectal Pathway: Laparoscopic Splenic Flexure Release (Tips…
Fig. 4.6 The attachments
of the retroperitoneum and
the mesentery of the
descending colon should
be identied and pushed
apart along an avascular
plane. This can be
developed bluntly and does
not require any sharp
dissection
Fig. 4.7 Color and texture
difference between
Gerota’s fascia and the
colon mesentery
51
immediately visualized and incised in a central to lateral fashion from roughly the
mid- transverse colon out to the splenic exure through the gastrocolic ligament.
The surgeon must be careful while performing this aspect of the operation to avoid
going too deep and inadvertently injuring the mesentery of the transverse colon.
This is a critical point as injury to the mesentery of the transverse colon will put at
risk the blood supply to the descending colon, which is necessary for the anastomosis. The dissection should be carried out laterally as far as can easily be accomplished. The dissection should then be carried out toward the upper 10cm of the line
of Toldt along the proximal descending colon. The attachments of the retroperitoneum and the mesentery of the descending colon should be identied and pushed
apart along an avascular plane. This can be developed bluntly and does not require
any sharp dissection (Fig. 4.6). By paying strict attention here, the surgeon can
notice the difference in color and texture of the fat of the colonic mesentery, deep to
Gerota’s fascia and retroperitoneal fat (Fig.4.7). Once this is mobilized, the hands
are switched so that the traction of the transverse colon is brought down to the left
hip by the right hand, and the energy source is coming from the left hand, bringing
the thermal spread and/or scissors away from the transverse colon and a wayward
diverticulum. The attachments of the greater omentum to the spleen must be carefully divided. Care must be taken not to put undue traction on the colon or the
52
ab
Fig. 4.8 (a, b) Left-right hand switch. Hands are switched so that the traction of the transverse
colon is brought down to the left hip by the right hand and the energy source is coming from the
left hand, bringing the thermal spread and or scissors away from the transverse colon and a wayward diverticulum
Fig. 4.9 Inferior border of
the pancreas. Identifying
the mesentery and incising
it approximately a
centimeter to the inferior
border of the pancreas, the
transverse colonic
mesentery can be liberated
from its attachment to the
retroperitoneum and along
Gerota’s fascia
A. Caycedo-Marulanda and J. H. Marks
greater omentum. The greater omentum may be attached to the splenic capsule as
this will potentially be an area where capsular tearing of the spleen can occur. It is
always a good idea at this point of the operation to gently pull medially on the
greater omentum while watching the spleen for movement, to gauge the adherence
and possible danger of this manipulation. For lower anastomoses, where a coloanal
or low rectal anastomosis is necessary, the mesentery must be released from the
inferior border of the pancreas. By identifying the mesentery and incising it approximately 1cm distal to the inferior border of the pancreas, the transverse colonic
mesentery can be liberated from its attachment to the retroperitoneum and along
Gerota’s fascia. If all these steps are completed as described above, splenic exure
release will be complete (Figs.4.8a, b and 4.9).
Inframesocolic Approach
The patient is positioned in steep Trendelenburg with maximal right side down, and
the small bowel is fully retracted to the right side of the abdomen. An incision is
made 1.5 cm above the insertion of the inferior mesenteric vein (IMV) into the
4 Master Program Colorectal Pathway: Laparoscopic Splenic Flexure Release (Tips…
53
splenic vein. By dissecting here in an avascular fashion, one will enter into the
lesser sac anterior to the pancreas. Care must be taken not to be too supercial and
enter into the mesentery of the transverse colon. Interruption of the blood supply
here can put at risk the blood supply to the descending colon which is essential for
a well-vascularized anastomosis to the rectum. However, when dissection is carried
along this avascular plane, this greatly facilitates takedown of the transverse colonic
mesentery from its attachments to the retroperitoneum and full mobilization of the
mesentery of the transverse colon. This dissection is extended cephalad and laterally, remaining supercial to Gerota’s fascia. During this dissection, it is imperative
to distinguish the difference in consistency and discoloration of the fatty tissue and
the inferior edge of the pancreas in order to stay on the anterior aspect of this latter
organ. As the dissection progresses, the descending colon is visualized from the
medial aspect. At this point, the lateral attachments are mobilized and the greater
omentum is taken off the transverse colon. In this fashion, the colon is entirely
mobilized. A considerable challenge of this approach is that, if the surgeon is not
careful, she/he can end up posterior to the pancreas and risk injuring it as well as the
splenic vein. While highly reliable and reproducible as a technique, this is the
approach with the highest potential for complications. It is particularly challenging
with obese patients. When learning this technique, it is advised that the surgeon
have a low threshold to merge this with the other approaches until the surgeon is
very familiar and comfortable with this anatomy and the outlined danger areas.
However, with careful manipulation, this approach allows for mobilization of the
colon without repositioning the patient.
Lateral toMedial Approach
This is the most commonly used SFR approach, and the one that most open surgeons are comfortable with. An incision is made along the line of Toldt and extended
toward the splenic exure. One must be mindful as one marches up the line of Toldt,
not to inadvertently extend behind the kidney. As the surgeon gets close to the
splenic exure, the surgeon remembers that she/he needs to direct the dissection
medially and not extend it cephalad. Cephalad extension will direct the surgeon
posterior and lateral to the spleen and up to the diaphragm. That being said, by staying slightly medial and scoring the supercial layer of the omentum, it is easier to
liberate the rest of the greater omentum off the transverse colon by applying a combination of blunt and sharp dissection. This facilitates full mobilization of the exure, especially in situations when the omentum and the mesentery are prominent
and fatty. From a minimally invasive standpoint, be it laparoscopic or robotic, the
challenge with this approach is the energy source being used for dissection (e.g., an
ultrasonic, bipolar, or monopolar energy). Lateral spread in this fashion invites the
possibility of injury to the colon or an unrecognized diverticulum of the descending
colon, distal transverse colon, or splenic exure. Therefore the surgeon must be
mindful at all times to protect the colon so as not to inadvertently injure it during
mobilization. Again, if a lower anastomosis is necessary, further dissection may be
54
necessary, including the mesentery of the transverse colon. This can be accomplished in a lateral to medial fashion. Care must be taken to avoid injury of the
mesentery or any major nearby vascular structures.
A. Caycedo-Marulanda and J. H. Marks
Pros andCons
In general terms, there are no specic contraindications for the procedure. However,
the surgeon must bear in mind that critical structures are very closely related in the
splenic exure area (left kidney, left renal vein, splenic vein, superior mesenteric
vessels, portal veins, pancreas). Any injury to those organs or entering into the
wrong plane can have serious consequences. There are situations in which the procedure can become very challenging from a technical standpoint as in redo surgery,
procedures in morbidly obese patients or in patients with prior pancreatitis or major
surgery in left upper quadrant.
Pitfalls andTroubleshooting
Laparoscopic splenic exure mobilization has traditionally been considered difcult and time-consuming. While some surgeons have advocated using the same
standardized approach to SFT in every case, as practicing surgeons it is essential to
be knowledgeable in all the different techniques so that difcult anatomy can be
addressed safely and an alternative approach can be selected when appropriate [16].
This aspect of the procedure requires a thorough understanding of the anatomy of
the neighboring structures in order to avoid injuries. As in any other laparoscopic
interventions, the recognition of unsafe scenarios or lack of progress should prompt
the surgeon to consider other strategies or conversion to an open approach.
Complications that can occur during SFR include injury to the mesentery of the
transverse or descending colon, which can affect perfusion of the left conduit. Once
the IMA is transected, colorectal and coloanal anastomoses are entirely dependent
on the blood supply from the middle colic artery and accessory vascular arcades,
including the marginal artery of Drummond, the arterial arc of Riolan, and the artery
of Moskowitz [5] (Fig.4.3).
Any injury to the marginal vessel that supplies the colon can render the anastomosis ischemic. Aside from dissecting into the wrong plane and inadvertently dividing the mesocolic vessels of the proximal colon, careless handling of the mesentery
can be costly and result in devascularization of the proximal colon [17]. The intraoperative use of uorescence imaging to assess perfusion can be helpful in gauging
adequate blood supply for the left colon before and after constructing the anastomosis [11, 18]. If more proximal colon needs to be mobilized to achieve a wellvascularized anastomosis, the colon attachments should be released fully from the
inferior border of the pancreas.
Other complications of SFR include splenic injury. The spleen is often not clearly
visualized, and no effort should be made to routinely see it. Regardless of the surgeon’s ability to see the spleen, it must be made certain that undue mobilization or