腹腔镜全直肠系膜切除术（TME）癌症（图文演示）

中文版：腹腔镜全直肠系膜切除术（TME）癌症（中文图文）

LAPAROSCOPIC   TOTAL   MESORECTAL   EXCISION   (TME)   FOR   CANCER
Authors
J Leroy, M Henri
Abstract
The description of the laparoscopic total mesorectal excision (TME) for cancer covers all aspects of the surgical procedure used for the management of rectal cancer.
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, risk of nerve damage, mobilization of sigmoid colon, mobilization of upper rectum, dissection of lower rectum, splenic flexure, division of rectosigmoid, extraction, direct anastomosis, J-shaped anastomosis.
Consequently, this operating technique is well standardized for the management of this condition.

1. Introduction

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Total mesorectal excision (TME) was thoroughly codified by Heald in 1988.
The procedure helps reduce the risk of local recurrence and the number of permanent colostomies while preserving adjacent anatomical structures (nerve plexuses), as shown by the results published by Heald et al. in 1998.
The authors performed this procedure laparoscopically for the first time in November 1991. The laparoscopic procedure has the major advantage of magnifying anatomical structures (Okuda et al., 1998). The laparoscopic approach does not alter the technical principles described by Heald.
Once the rectum has been excised, continuity of the digestive tract is re-established via low colorectal anastomosis or colo-anal anastomosis. We shall focus on low colorectal anastomosis.

2. Indications
Rationale
Total “en bloc” resection of the rectum and its mesentery for the treatment of rectal cancer has an anatomical rationale (Hida et al., 1997; Quirke et al., 1986). It should be performed “en bloc” without infraction of the surrounding fascia to avoid local tumor seeding (Enker et al., 1995; Hida et al., 1997). An oncologic resection is done as the local lymph node relays are resected.
The risk of local recurrence correlates with the quality of the excision. This is dependent on the surgeon’s experience (Kockerling et al., 1998).
Lymph node metastases occur in the distal mesorectum in 20% of cases, and depend on the localization and depth of invasion of the tumor. The rate of lymph node metastasis is 10% for the rectosigmoid, 26.3% for the upper rectum, and 19.2% for the lower rectum. The rate is 0% for pT1 and pT2 tumors, 21.9% for pT3 tumors, and 50% for pT4 tumors (Hida et al., 1997).

Indications
Total mesorectal excision is indicated in rectal cancers located 2 to 10 cm above the anal canal. It is recommended in T3 and T4 tumors of the lower rectum. The mesorectum should be excised at least 5 cm below the tumor for T3 and T4 tumors of the upper rectum (Hida et al., 1997).
Preoperative radiation therapy is recommended in T3 and T4 lesions. It does not impair the surgical approach, laparoscopic approach included, provided surgery is done 6 weeks after the end of radiation therapy. Prior to this, massive pelvic edema may complicate dissection.

Contraindications
- contraindications to laparoscopic surgery;
- tumor with invasion of neighboring organs (T4 tumor);
- voluminous tumor;
- multiple abdominal scars.

3. Operating room set-up

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The patient must be positioned carefully, to avoid complications (nerve and vein compression, injuries of the brachial plexus) and facilitate the procedure and anesthetic monitoring.
The patient can be either secured by supports fixed above the shoulders, or strapped at chest level to prevent slippage.
- Trendelenburg position with a 15° to 25° tilt and a 5° to 10° right tilt;
- moderate lateral decubitus via a sandbag tucked below the left half of the body: this helps lower the organs to the right of the abdominal cavity;
- Lloyd-Davis position, allowing for both abdominal and perineal access: it is essential that the perineum be positioned at the distal edge of the table to facilitate the introduction of a circular stapler during colorectal anastomosis or to perform a colo-anal anastomosis;
- thighs and legs stretched apart with a slight flexure of hips and knees so that positioning of an assistant is easier and instruments can be better handled;
- right arm alongside the body so that an assistant can stand lateral to the right shoulder of the patient;
- left arm at a right angle or preferably alongside the body;
- gastric tube and urinary catheter to drain the bladder and stomach and control diuresis intraoperatively;
- heating device to limit the dissipation of heat.

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Although the procedure can be completed with 1 assistant, it is preferable to have 2 assistants and a scrub nurse, especially at the start of the surgeon’s experience with the technique.
The surgical team remains in the same position throughout the entire procedure.
1. Surgeon
2. First assistant
3. Second assistant
4. Scrub nurse
5. Anesthesiologist

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The operating table must allow for both abdominal and perineal access. A table that can be easily tilted by remote control, thereby facilitating perineal exposure, is recommended. The laparoscopic unit is located to the left of the patient. It includes a main monitor, a 3CCD camera (indispensable to perform the procedure in excellent conditions) and a high output (>= 9L/min) insufflator used to monitor pressures electronically. Its inertia should be low to make up for losses in carbon dioxide (induced or not).
The voice-controlled robotic arm or camera-holder is increasingly used to replace the assistant who holds the camera. It offers greater image stability during dissection.
1. Laparoscopic unit
2. Electrosurgical generator
3. Operating table
4. Monitors
5. Ultrasonic generator
6. Instrument table

4. Trocar placement

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Although a sigmoidectomy is possible with only 3 trocars, in complicated cases and especially when the surgeon’s experience is limited, more trocars are recommended. This improves safety, exposure of the operative field, and mobilization of the splenic flexure.
We prefer to use 6 trocars, with a trend toward reducing the size of trocars. The patient’s body habitus, previous surgical history, and the initial laparoscopic exploration via the supraumbilical trocar help in guiding the introduction of the various operating trocars.
Firm fixation of trocars to the abdominal wall can limit the risk of tumor seeding (Balli et al., 2000). Increased trocar stability also facilitates the procedure, and is achieved by adapting the size of the incision to the trocar, either by fixing the trocar to the skin with a suture or by using orthostatic trocars.

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Trocar A: 12 mm optical trocar
This first trocar is positioned on the median line above the umbilicus or 20 cm above the pubis in short patients.
This trocar accommodates a 0° optical.

• Operating

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Trocar B is a 5 mm trocar situated on the right midclavicular line, at the level of the umbilicus. It is used as an operating trocar during the dissection of the rectum and sigmoid colon and during the mobilization of the splenic flexure (caudal retraction of the left colon).
This trocar accommodates an atraumatic grasper.

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Trocar C is a 5 mm trocar situated on the right midclavicular line, 8 to 10 cm inferior to trocar B. It is used as an operating trocar during the dissection of the rectosigmoid. It is used as a retracting trocar during the mobilization of the splenic flexure (caudal retraction of the left colon).
At the end of the procedure, it can be replaced by a 12 mm or 15 mm trocar for the introduction of a linear stapler.
This trocar accommodates:
- scissors (monopolar, ultrasonic dissector, clip, staplers), bipolar hook, surgical loop, suction-irrigation device;
- an atraumatic grasper.

• Retractors

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Trocar D is a 5 mm trocar situated on the left midclavicular line, at the level of the umbilicus. It is used as a retracting trocar except during the mobilization of the splenic flexure, when it becomes an operating trocar.
This trocar accommodates:
- an atraumatic grasper;
- scissors (monopolar, ultrasonic dissector, vessel sealing device, clip, staplers), bipolar hook, surgical loop, suction-irrigation device.

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Trocar E is a 5 mm trocar situated 8 to 10 cm above the pubic bone on the median line. It is used as a retractor except during the division of the lower rectum when it can be replaced by a 12 mm or 15 mm trocar to introduce a linear stapler. A grasper is passed through it. It is used to expose the sigmoid mesocolon and the left mesocolon. A flexible retractor is passed through trocar E during the anterior dissection of the rectum.
This trocar accommodates a grasper, a suction-irrigation device, a stapler, and a flexible retractor.

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Trocar F is a 5 mm retracting trocar situated on the right midclavicular line below the costal margin. An atraumatic grasper is passed through it. It is used to retract the terminal portion of the small intestine laterally and to better expose the attachments of the omentum to the transverse colon during mobilization of the splenic flexure.
This trocar accommodates an atraumatic grasper.

5. Instruments

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We prefer to use 0° or 30° angle scopes with a 70° visual field.
Some surgeons use a 45° angle scope; others, like Milsom and Okuda, use a flexible fiberoptic laparoscope that offers multiple scope angulation during dissection.
1. 0° laparoscope
2. 30° laparoscope
3. Flexible laparoscope

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1. Grasper
2. Bipolar forceps
3. Ultrasonic scissors
4. Articulated linear stapler
5. Scissors
6. Circular stapler
7. Vessel sealing device

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1. Suction-irrigation device for lavage and dissection (lysis of adhesions)
2. Traumatic French needle to close trocar openings in obese patients
3. Purse-string applier
4. Clip applier
5. Wound protector
6. Extraction bag
7. Pelvic flexible retractor

6. Exploration

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The first step is the exploration of the abdominal cavity, starting with a panoramic exploration to assess the tumoral extension. Visceral organs can be manipulated with atraumatic instruments to complete the exploration.
The length of the sigmoid loop, the quality of the wall of the sigmoid colon and its fixation in the pelvis, and the motility of the descending colon should be assessed.

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Recommended by some authors (Milsom et al., 2000), ultrasonography is carried out with a flexible, sterile, and reusable 10 mm probe.

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Localization of the tumor is indispensable for upper rectal tumors to avoid too large a resection of the middle and lower rectum. If the tumor cannot be visualized, localization is performed via endoscopy by dye-marking (india ink) at the beginning of the procedure or the evening before the procedure (Kim et al., 1997; Okuda et al., 1998).

7. Exposure
• Patient preparation

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Exposure depends largely on the space available for retraction of the small bowel loops in the abdominal cavity, and on the positioning of the patient. Complete emptiness of the digestive tract greatly facilitates the layering of bowel loops. Emptying is achieved by a strict, low-residue diet commenced 3 to 8 days prior to surgery. We no longer use polyethylene glycol that was administered 2 days before surgery to complete bowel preparation. The day before, or even on the day of the operation, the patient is placed on a fibre-free diet and undergoes enemas.
Gastric emptying is done by means of a gastric tube.

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In addition to the pneumoperitoneal pressure (12 mm Hg), complete relaxation of the muscular wall is essential to create the working space.
1. Muscle relaxation
2. Distension of muscular wall
3. CO2 <= 12 mm Hg

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

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

The distal ileum is placed in the right lower quadrant along with the cecum. If the small intestine is too dilated, this operative maneuver may be difficult, notably in obese patients.

1. Retraction of the greater omentum
2. Trendelenburg position
3. Right tilt
4. Retraction of the intestinal loops to the right

&#8226; Specific cases

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The use of specific retractors, eg flexible retractors, is very useful during anterior dissection of the lower rectum. They are introduced in the suprapubic trocar E.
1. Retractor

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Obesity reduces the operating space. Obesity characterized by a flaccid muscular wall (female patients) is not a major handicap as ample working space remains and the mesocolon is longer. When obesity is characterized by a tonic muscular wall (male patients) and short, fatty mesenteries, the surgeon has to progressively layer the intestinal loops to expose the operative field.

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Adhesions, when present, are divided to free the bowel and achieve a better exposure. However, it is sometimes useful to preserve adhesions, notably at the level of the cecum, the sigmoid colon or the splenic flexure.

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The uterus can be an obstacle to good exposure of the pelvis. In post-menopausal patients, the uterus can be attached to the anterior abdominal wall by a transparietal suture. This suture is introduced halfway between the umbilicus and the pubis to make the axis of the vagina horizontal, thereby opening the rectovaginal space.

8. Vascular approach

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In rectal cancer, the vascular approach is combined with a lymphadenectomy. Perirectal lymph nodes and lymph nodes of the inferior mesenteric chain are removed. However, division of the inferior mesenteric artery (IMA) at its origin and of the inferior mesenteric vein (IMV) at the inferior border of the pancreas is not mandatory to achieve an oncological resection.
The primary vascular approach allows for a medial and posterior dissection of the sigmoid mesocolon, while avoiding manipulation of the colon, rectum, and tumor (Okuda et al., 1998). This helps preserve the working space during the mobilization of the sigmoid colon and rectosigmoid junction.
The IMA should be clipped and divided before the IMV to avoid venous congestion in the mesocolon, which can result in oozing during dissection.
Before these vessels are divided, the sympathetic nerve trunks and the left ureter should be identified and preserved.
1. Sigmoid trunk
2. Superior rectal artery (SRA)
3. Aorta
4. Left colic artery (LCA)
5. Inferior mesenteric artery (IMA)

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The sigmoid mesocolon is retracted anteriorly using a grasper introduced in trocar E. The peritoneum is then opened cephalad, proceeding along the right anterior border of the aorta from the promontory up to the duodenojejunal junction. The incision then crosses to the left toward the splenic flexure to expose the anterior surface of the IMV.
CO2-induced dissection secondary to pneumoperitoneal pressure opens an areolar plane, which makes this step easier.
1. Promontory
2. Right border of the aorta
3. Third portion of duodenum

&#8226; Division of the IMA

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Division of the IMA near its origin, 1 cm from the aorta, and including the division of the LCA, aims at removing the surrounding lymph node tissue, to achieve an oncological resection. Dividing the IMA at its origin is associated with a risk of injury to the left sympathetic trunk situated on the left border of the IMA. This injury can be avoided if the dissection is carried out close to the IMA. Clips or the use of a vessel-sealing device are more precise and should be preferred to the use of linear staplers to avoid the division of the left sympathetic trunk and ureter.

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Once the peritoneum is opened, the dissection proceeds caudad to cephalad over the whole length of the incision, dividing the fatty and fibrotic tissues.
The aorta and the IMA are progressively identified. Once the right wall of the IMA has been identified, the artery is isolated near its origin below the duodenojejunal junction. The nerve branches that originate from the right para-aortic sympathetic trunk and the intermesenteric plexus and cover the IMA are divided one after the other. During dissection, the IMA is skeletonized while the branches of the periaortic sympathetic plexus are preserved.
The right branches of the superior hypogastric nerve that obliquely cross the aorta anteriorly and inferiorly to the IMA are preserved to avoid functional genitourinary sequelae. This step is crucial as it helps safe dissection of the IMA at its origin.

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Division of the IMA after the origin of the LCA combined with a large perivascular dissection also allows an oncological lymphadenectomy.
This technique helps to preserve the vascular supply of the left colon, but it can be an obstacle to splenic flexure mobilization. The sympathetic nerve trunks situated to the left of the IMA should be preserved. Their division can result in urinary dysfunction and ejaculation disorders in men.
1. Left colic artery (LCA)

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The IMV is identified to the left of the IMA, or in case of difficulty, to the left of the duodenojejunal flexure. It is then crossed anteriorly by the LCA, which then runs along its left border.
The IMV is retracted anteriorly with a grasper introduced in trocar E. Before division it is freed from the left sympathetic nerve trunk on its posterior surface. On its left border, it is freed from the LCA.
The IMV is divided between 2 clips below the inferior border of the pancreas, with care taken not to confuse it with the splenomesenteric trunk. The IMV can be divided later to preserve the ''tenting'' effect, which retracts the small bowel during the dissection of the sigmoid mesocolon.
1. Left colic artery
2. Inferior mesenteric vein

9. Risk/nerve damage

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There is a risk of injury to the hypogastric nerves (purely sympathetic) during ligation of the inferior mesenteric artery (IMA) at its origin and during dissection along the left border of the IMA.

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There is a risk of injury to the hypogastric nerves (purely sympathetic) during posterior dissection of the rectum in the presacral space.

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The inferior hypogastric nerves (mixed sympathetic and parasympathetic) may be exposed to injury if there is excessive lateral traction on the rectum during its lateral dissection.

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The cavernous nerves (parasympathetic), located at the postero-lateral border of the apex and base of the prostate, may be injured during the anterior dissection, particularly when it is performed anterior to Denonvilliers’ fascia.