腹腔镜下乙状结肠憩室炎（图文演示）

中文版：腹腔镜下乙状结肠憩室炎（中文图文演示）

LAPAROSCOPIC   SIGMOIDECTOMY   FOR   DIVERTICULITIS
Authors
J Leroy, J Milsom, J Okuda
Abstract
The description of the laparoscopic sigmoidectomy for diverticulitis covers all aspects of the surgical procedure used for the management of sigmoid diverticulitis.
Operating room set up, position of patient and equipment, instruments used are thoroughly described. The technical key steps of the surgical procedure are presented in a step by step way: exploration, exposure, vascular approach, vascular division, posterior medial dissection, resection of mesorectum, lateral mobilization, division of sigmoid colon, mobilization principles, lateral mobilization, medial mobilization, extraction, preparation of anastomosis, anastomosis.
Consequently, this operating technique is well standardized for the management of this condition.

1. Introduction
Symptomatic and complicated diverticular disease represents the most common indication for sigmoid colectomy in Western countries. As these resections are performed for benign disease, care must be taken to minimize any untoward sexual or urinary postoperative sequelae.
A laparoscopic approach may be used to perform sigmoid resection in a manner equivalent to the open technique. Indeed, most laparoscopists consider laparoscopic sigmoid colectomy relatively straightforward. However, the difficulty of the procedure increases significantly with complicated diverticular disease.

2. Anatomy

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The sigmoid colon is the mobile terminal portion of the left colon. Its mobility depends on the length of the sigmoid loop.
The vascular supply of the sigmoid colon is based entirely on the inferior mesenteric artery and its branches. Thorough knowledge of the vascular anatomy and its variations is essential for a safe resection.
The close proximity of the vessels to the left sympathetic trunk and the left ureter represent potential risks in sigmoid colon resection.

• Arteries

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The arteries are all branches of the inferior mesenteric artery (IMA).
1. Inferior mesenteric artery (IMA)
2. Left colic artery (LCA)
3. Trunk of sigmoid arteries
4. Superior rectal artery (SRA)
5. Marginal arteries

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The inferior mesenteric artery (IMA) originates from the anterior surface of the abdominal aorta, 1 to 3 cm below the third portion of the duodenum, to form the main blood supply of the left colon. It gives off branches for the left colon, the sigmoid colon, and the rectum.

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The left colic artery (LCA) is the first branch of the IMA and supplies the vasculature of the left colon. After crossing over the inferior mesenteric vein (IMV), the LCA courses along the IMV's left border for a variable distance. It then approaches the marginal arteries, which it generally joins somewhere between the splenic flexure and the transverse colon. Its preservation is possible during mobilization of the left colon.

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The superior rectal artery (SRA) is the terminal branch of the IMA. It is located just anterior to the fascia propria of the rectum at the rectosigmoid junction. It gets progressively closer to the rectal wall as it divides into a right and a left branch, or into even more branches in 17% of cases (Ayoub, 1978). These branches supply the upper two thirds of the rectum. The larger right branch often extends from the IMA (Ayoub, 1978). These 2 branches divide 2 or 3 more times without anastomosing and end on the pelvic floor. All these arterial branches remain in the mesorectum along with the rectal veins, which drain into the superior rectal vein (SRV) and then into the IMV.

• Veins

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Rectal, sigmoid, and left colic veins join to form the inferior mesenteric vein (IMV).
1. Inferior mesenteric vein (IMV)
2. Left colic vein (LCV)
3. Trunk of sigmoid veins
4. Superior rectal vein (SRV)
5. Marginal veins

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The sigmoid and left colic veins join to form the inferior mesenteric vein (IMV).
1. Portal vein
2. Splenomesenteric trunk
3. Splenic vein
4. Inferior mesenteric vein (IMV)
5. Superior mesenteric vein (SMV)

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There are several sigmoid veins (SV). They run separately or as a common trunk into the SRV to form the IMV.

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The left colic veins (LCV) often join into a main trunk. There are often 2 LCVs for 1 LCA. Accessory venous branches, originating from the descending colon, run directly into the IMV. They must be divided to allow mobilization of the left colon.

3. Operating room set-up

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It is essential that the patient be appropriately positioned to avoid complications (nerve and vein compression, injuries to the brachial plexus) and to facilitate the procedure and anesthetic monitoring.
- Trendelenburg position with a 15° to 25° tilt and a 5° to 10° right tilt;
- lithotomy position;
- buttocks placed at the distal edge of the table;
- thighs and legs stretched apart with a slight flexure;
- right arm alongside the body;
- left arm at a right angle or alongside the body (surgeon's preference);
- gastric tube and urinary catheter;
- heating device.

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1. Surgeon
2. First assistant
3. Second assistant
4. Scrub nurse
5. Anesthesiologist
Although the procedure can be performed with a single assistant, it is preferable to have 2 assistants and a scrub nurse, especially when experience in performing the procedure is limited.
The team can remain in the same position throughout the entire procedure.

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- The table must allow for both abdominal and perineal access. It is advisable to use a table that can be easily tilted laterally and placed into steep Trendelenburg and reverse Trendelenburg position, facilitating perineal exposure.
- The laparoscopic unit is located to the left of the patient along with the main monitor. It may be useful to use a second monitor placed above the patient's head.
- To perform the procedure in excellent conditions, a 3CCD camera is mandatory.
- A high output (>= 9L/min) insufflator should be used to electronically monitor pressures. Its inertia should be low to make up for losses in carbon dioxide (induced or not).
- Voice-controlled robotic arm
1. Laparoscopic unit
2. Electrocautery
3. Operating table
4. Monitor
5. 3CCD camera
6. Instrument table

4. Trocar placement

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Although a sigmoid colectomy can be performed using only 3 trocars, for complicated presentations and especially when the surgeon's experience in performing the technique is limited, the use of more trocars is preferable. This helps to ensure the safety of the procedure by allowing improved exposure of the operative field and the mesentery, and by facilitating mobilization of the splenic flexure.
We readily use 6 trocars, with a trend toward reducing trocar size. The patient's body habitus, previous surgical history and the initial laparoscopic exploration via the supraumbilical trocar should be used as guides for introducing the various operating trocars.

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Firm trocar fixation in the wall is important. This is achieved by adapting the size of the incision to the trocar and, if needed, fixing the trocar to the abdomen with a suture. We no longer use screw-like devices, as they increase parietal trauma.

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Trocar A: 10/12 mm, 0° optical
The trocar is positioned on the median line 3 to 4 cm above the umbilicus or 20 cm above the pubis in patients with a small stature.
0° optical

• Operating

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This is a 5 mm operating trocar, used for retraction during mobilization of the splenic flexure (caudal retraction of the left colon), during which time trocar D is used for operating instruments. At the end of the procedure, Trocar B may be replaced by a 12 or 15 mm trocar for introduction of a linear stapler.
It is situated on the right midclavicular line, at the level of the umbilicus.
Atraumatic grasper

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This is a 5 mm operating trocar, used for retraction during mobilization of the splenic flexure (caudal retraction of the left colon). At the end of the procedure, it may be replaced by a 12 or 15 mm trocar for introduction of a linear stapler.
It is situated on the right midclavicular line, 8 to 10 cm below trocar B.
Scissors (monopolar, high-frequency hemostasis device, clip, staplers), bipolar hook, surgical loop, suction-irrigation device
Atraumatic grasper

• Retractors

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This is a 5 mm retractor, except during mobilization of the splenic flexure, when it is used as an operating trocar.
It is situated on the left midclavicular line, at the level of the umbilicus.
Atraumatic grasper
Scissors (monopolar, high-frequency hemostasis device, clip, staplers), bipolar hook, surgical loop, suction-irrigation device

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This is a 5 mm retractor, except during mobilization of the splenic flexure when it is used as an operating trocar. It accommodates a grasper used to expose the mesosigmoid and left mesocolon.
It is situated 8 to 10 cm above the pubis on the median line.
Grasper, suction-irrigation device

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This is a 5 mm retractor that accommodates an atraumatic grasper used to laterally retract the terminal portion of the small intestine and to better expose the attachments of the omentum to the transverse colon during mobilization of the splenic flexure.
It is situated on the right midclavicular line in the subcostal position.
Atraumatic grasper

5. Instruments

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Most authors use laparoscopes with 0° and 30° visual axes and with a 70° visual field.
Some authors use a laparoscope with a 45° visual axis.

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1. Grasper
2. Bipolar
3. Ultrasonic dissectors
4. Linear stapler
5. Scissors
6. Clip applier
7. Circular stapler
8. Plastic-coated drape to protect the incision after freeing the colostomy

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1. Flexible retractor
2. Peanut swab

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Efficient suction-irrigation device for lavage and dissection (lysis of adhesions)

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The first step of the procedure is an exploration of the abdominal cavity. Visceral organs may be manipulated with blunt instruments to complete the exploration and to evaluate the colon.
The length, degree of inflammation, and presence of pelvic adhesions of the sigmoid loop are evaluated. Similarly, the quality and mobility of the left colon are assessed.

7. Exposure

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Improved exposure greatly facilitates the surgical procedure.
Proper exposure is a function of a host of factors. These include the working space in the abdominal cavity, the quality of the preoperative gastrointestinal (GI) preparation, the positioning of the patient as well as a perfect understanding of the organization of the operating field.

• Working space

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This depends on the quality of the preoperative GI preparation, the positioning of the patient and complete relaxation allowing the abdominal wall to distend correctly under the pressure of the pneumoperitoneum.

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An empty digestive tract facilitates the layering of intestinal loops. It is achieved by a strict, fiber-free diet 8 days prior to surgery.
As most experts do, polyethylene glycol is no longer used before surgery to complete the intestinal preparation.
The day before, or even on the day of the operation, the patient is placed on a fibre-free diet and undergoes enemas.

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To prevent the patient from sliding, shoulder supports or straps around the thorax may be used.
In our current practice, we rarely use such measures, despite a 20° to 30° Trendelenburg position and a right tilt.

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In addition to the pressure of the pneumoperitoneum (12 mm Hg), complete relaxation of the muscular wall is essential to create the working space.

• Layering the intestinal loops

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Layering the intestinal loops requires gravity and retraction of organs.

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The greater omentum and the transverse colon are placed in the left subphrenic region and maintained in this position by the Trendelenburg tilt. An atraumatic retractor, introduced through trocar D, may also be used.

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The jejunum is retracted toward the right hypochondrium, below the right transverse colon. The right tilt and Trendelenburg position, along with an atraumatic retractor if needed, maintain the small intestine in this position.

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The distal portion of the small intestine is placed in the right iliac fossa along with the cecum. If the small intestine is too bulky, this operative maneuver can be difficult, notably in obese patients.

• Specific cases
• Obese patient
Obesity characterized by a flaccid muscular wall (female patients) is not a major handicap as ample working space remains. In the setting of a tonic muscular wall (male patients) and short, fatty mesenteries, the surgeon must progressively layer the intestinal loops to expose the dissection areas.

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By freeing the digestive tract, layering can be performed for better exposure of the operating field. It is sometimes useful to preserve adhesions, especially at the level of the cecum or the splenic flexure.

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The uterus may be an obstacle to adequate exposure in the pelvis. In postmenopausal female patients, the uterus can be suspended to the abdominal wall by a suture. This suture is introduced halfway between the umbilicus and the pubis to suspend the vagina and make it horizontal, thereby opening the rectovaginal space.

8. Vascular approach

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The vascular approach is the first step of the dissection. A medial approach from right to left is used.
When a segmental resection of the sigmoid colon is planned, it is advisable to preserve the vascular supply of the left colon and rectum to improve short and long-term results (Adachi, 2000).
Except in simple cases where vessels are visible due to transparency, the vessels are gradually exposed once the peritoneum of the mesosigmoid has been widely opened.

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The peritoneum is opened along the right anterior border of the aorta, starting the incision from the promontory and extending it to just below the third portion of the duodenum.
Anterior traction of the mesosigmoid, using a grasper introduced through trocar E, exposes the base of the mesosigmoid. The pneumodissection (entry of CO2 into the retroperitoneal space), which results from the pneumoperitoneum, facilitates the dissection.

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After division of the perivascular fibrous elements, the IMA trunk is identified near the aorta.
This identification is mandatory in obese patients or in cases of severe mesenteric inflammation, in order to identify the arterial branches that must be preserved.

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The dissection of the IMA near its origin is pursued caudally along its anterior aspect, opening the vascular sheath.
The left colic branch on the left aspect of the IMA is rapidly identified, followed successively by the trunk of the sigmoid arteries and the SRA.
The dissection of these vessels must be meticulously pursued to identify any vascular anomalies. Indeed, sigmoid branches (SB) can also originate from the LCA and the SRA.

9. Vascular division

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Some authors consider division under laparoscopic guidance of the IMA near its origin easier than preservation of the left colic and superior rectal vessels (Domergue, 2000; Leroy, 2000). However, this is not recommended in benign pathologies, as anatomical and functional studies have shown that preservation of the LCA and SRA leads to improved short-term and long-term results (Adachi, 2000).

• Division of IMA

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1. Toldt's fascia
2. Sympathetic trunk
3. Ureter
4. IMV
5. LCA
6. Peritoneum
Division of the IMA is performed either after applying clips, or after sealing the vessels with a hemostasis device. The distal end of the SRA at the level of the mesorectum must also be controlled during the procedure. Preservation of the LCA is possible, in which case care must be taken to avoid injuring the left sympathetic trunk situated on the left border of the IMA.

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Performed 1 cm from the aorta, this technique is used when the inflamed mesentery is difficult to dissect.

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This allows preservation of the vascular supply of the left colon, but it can limit the mobility of the left colon.

• Division of sigmoid arteries

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We recommend selective division of the sigmoid branches, thus preserving the left colic and superior rectal arteries.
The risk of injury to the hypogastric nerve plexus and to the left ureter is relatively low at this level. Nevertheless, the left ureter must be identified before any ligature, cauterization or division.

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The sigmoid trunk must be divided at its origin, either after applying clips or after sealing the vessels with a hemostasis device. This trunk is always situated anterior to the SRV, which must be preserved.

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These branches may be divided separately (after applying clips or using a vessel-sealing device) or together after creating windows in the mesentery to divide the various branches with a linear stapler.

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Dissection of the anterior surface of the superior rectal vessels exposes the sigmoid branches that must be divided. These vessels may be encountered up to the level of the promontory.
Dissection of the first few centimeters of the LCA is performed to check for the presence of sigmoid branches arising directly from it. Such branches, if present, are divided separately.

• Division of veins

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As a rule, the veins, situated lateral to the arteries, are easily identified after division of the sigmoid artery trunk. In case of difficulty, the vein trunk is identified further down on the left margin of the SRA.
In our opinion, preservation of the IMV is important and does not prevent the lowering of the left colon.

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In our early experience with laparoscopic sigmoid colectomies, we systematically divided the IMV below the LCV or below the inferior border of the pancreas, after division of the IMA (Leroy, 2000). In our current practice, however, we try to preserve it. In the presence of severe inflammation preservation of the IMV can be difficult and in such cases it is sacrificed.

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The sigmoid veins are often paired with the sigmoid arteries, although there may be more than one venous branch for each arterial one. This is particularly true on the anterior surface of the SRV.

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This step is almost always required in order to lower the splenic flexure with or without preservation of the LCA.