The indications of anal preservation surgery for rectal cancer are, in a broad sense, to try not to bear the scolding name of local recurrence brought by anal preservation surgery; in a chivalrous sense, anal preservation surgery can be performed if the surgical anal canal still exists after radical resection of the tumor.
According to embryonic development and tissue morphology, from below the dentate line to the anal verge is called anatomical anal canal, and the anatomical anal canal is about 1.5-2 cm long. From the clinical application and surgical point of view, from the upper edge of the rectal loop to the anal verge (i.e., the lowest part of the plane of the levator muscle to the anal verge) is called the surgical anal canal; the surgical anal canal is about twice as long as the anatomic anal canal. Generally, if the following conditions are met by preoperative rectal examination and pathological examination, anal preservation surgery for rectal cancer can be considered: (1) the lower edge of the tumor base is 5 cm or more from the anus (2 cm or more from the upper edge of the surgical anal canal), (2) the tumor is a limited augmentation or ulcerative lesion, and the tumor occupies no more than 1/2 of the intestinal wall, (3) the intestinal wall at the base of the tumor is soft, or the base of the tumor is mobile, and (4) the tumor pathology is tubular or papillary adenocarcinoma. The tumor pathology is tubular adenocarcinoma or papillary adenocarcinoma. Generally, preoperative CT or MRI indicates that the tumor does not involve the surgical canal, there is no obvious external infiltration of the tumor (T1-3), and there is no extensive lymph node metastasis in the rectal mesentery. If the tumor has involved the surgical anal canal, or there is obvious external infiltration that cannot guarantee the negative circumferential margin, or there is extensive lymph node metastasis, consider the high rate of local recurrence in the pelvic cavity after surgery, and it is not suitable for anus-preserving surgery.
With the emergence of laparoscopy, ultrasonic knife and double anastomosis, the new era of laparoscopic anal preservation surgery for rectal cancer has arrived. This article, combined with personal experience, focuses on the evaluation of various rectal cancer anus-preserving procedures.
(A) Double anastomosis surgery (double stappling)
The double stappling technique was first adopted by Griffen and Knight in the 1980s, and was introduced to large hospitals in China in the 1990s and translated into the double anastomosis technique to be promoted. The basic principle of the technique is to close the rectal stump and resect the specimen for the first time, and then to anastomose the rectal stump and the broken end of the colon with an anastomosis clutch with a puncture rod for the second time. The double anastomosis technique greatly reduces the workload of the surgeon and shortens the operation time, thus greatly promoting anal preservation surgery, which is the preferred surgical method for anal preservation.
However, some hospitals adopt double anastomosis technique to preserve anus, especially for rectal cancer that is very close to the anus, which may lead to: ① or failure of anus preservation. (ii) or tumor recurrence. Insufficient resection of the lower margin of the tumor is the main cause of tumor recurrence after surgery. (iii) or anal pain. Some of them staple the anastomosis to the dentate line, which causes pain to the patient and decreases the quality of life.
As early as the third national symposium on anal preservation for rectal cancer in Hangzhou in 2001, the consensus opinion was obtained that double anastomosis is preferred based on the principle of radical tumor treatment, and Parks or modified Bacon surgery can be used when double anastomosis is inconvenient. I know that for low rectal cancer with the base of the tumor 6-8 cm from the anal verge, double anastomosis with low anterior resection is feasible; for a few thin patients, low rectal cancer with the base of the tumor 5-6 cm from the anal verge and the mass located in the posterior wall of the rectum, double anastomosis with low anterior resection can also be performed after the rectum is sufficiently free to have a certain degree of extension. For low rectal cancer whose base is 5-6 cm from the anal verge, it is more radical to use Parks or modified Bacon operation.
I believe that double anastomosis surgery for rectal cancer with the base of tumor 7-8 cm from the anus is not easy to occur, and it is not necessary to perform protective intestinal stoma during surgery; for rectal cancer with the base of tumor 6-7 cm from the anus (patients with the base of tumor 5-6 cm from the anal verge and the mass is located in the posterior wall of the rectum), it is better to perform protective ileostomy during surgery to prevent anastomotic fistula.
(ii) Transanal resection of rectal cancer
At the earliest stage, due to the limitation of surgical technique, the intestinal tube with the tumor was turned out through the anus and dragged out of the anus, and the specimen was excised to complete the anastomosis between the rectal stump and the broken end of the colon, and then the anastomosis was pushed into the pelvis after the completion of the anastomosis, which is also called Welch operation. However, if the tumor containing a large size is turned out through the anus, it will definitely be squeezed by the anus, which may lead to the spread of tumor cells and does not comply with the principle of tumor-free; moreover, if the rectum can be turned out of the anus to do anastomosis, it can definitely do a double anastomosis in the pelvis. Therefore Welch procedure is not widely promoted.
The development of things always follows the law of negation. With the development of laparoscopic rectal cancer anus-preserving surgery, the lack of the judgment of the abdominal group doctor’s palpation on the lower incision margin of the tumor may sometimes result in insufficient resection of the lower incision margin or even positive lower incision margin. In order to achieve radical resection of tumors, Zhang Wei of Shanghai Changhai Hospital and Zuo Zhigui of the First Affiliated Hospital of Wenzhou Medical College proposed that for rectal cancer or rectal villous adenoma that is not very large and close to the anus, after the pelvic cavity is fully free of the rectum, it is turned out and dragged out of the anus via the anus, and the tumor specimen is removed in a conformal manner under direct vision.
In order to complete the transanal resection conveniently, Dr. Ping Huang of the First Affiliated Hospital of Nanjing Medical University has recently developed a “long rod mushroom” (commonly known as “drag-out device”) for the purpose of turning out and dragging out.
After excision of the tumor specimen under direct vision, it is necessary to combine with double anastomosis technique, or manual anastomosis of colon and anal canal, or colon pull-out technique to complete the restoration of continuous passage between large intestine and anus.
(iii) Coloanal anastomosis (Parks procedure)
With the emergence of double anastomosis, laparoscopy and ultrasonic knife, the use of anal preservation for rectal cancer more than 6 cm from the anus has been increasing. For rectal cancer 5-6 cm away from the anus, it is difficult to preserve the anus, or it is painful to preserve the anus and lead to anastomotic recurrence after surgery.
The basic principle of Parks procedure is to free the rectum to the upper edge of the surgical anal canal, cut the specimen with an ultrasonic knife at the upper edge of the surgical anal canal, remove the mucosa above the dentate line with an ultrasonic knife (or burn the mucosa above the dentate line with an electric knife spark) by the perineal group, and intermittently suture the broken end of the colon and the dentate line (with part of the anal sphincter tissue). Suture, also known as manual anastomosis of the colon and anal canal.
The technique was first applied by Prof. Zhou Xigeng and his disciple Prof. Yu Baoming at Shanghai Ruijin Hospital, the founder of anorectal surgery in China in the last century, and it is also frequently performed by well-known specialists such as Prof. Qiu Huizhong at Peking Union Medical College Hospital and Prof. Li Shiyang at Beijing Military General Hospital.
I experience that Parks surgery can indeed be useful when double anastomosis surgery cannot be applied to preserve anus in low rectal cancer, but the incidence of anastomotic fistula is greater after Parks surgery, and a protective enterostomy is required. The main reasons for this are: (1) the anus is in a semi-empty state in the pelvic cavity, and the colonic dissection on one side of the anastomosis is under the effect of gravity causing a certain tension on the anastomosis, and (2) the sphincter contraction of the anus can cause the colonic dissection at the upper end of the anastomosis to return to depth together with the nearby tissues of the mesentery. Both of these causes may lead to anastomotic fistula due to anastomotic disintegration, and sometimes even serious loss of continuity of the colonic dissection and the anal canal.
If an anastomotic fistula occurs after Parks surgery, a protective enterostomy will greatly help the patient’s recovery, but it is still necessary to place an anal tube through the anus to drain the anus until there is no purulent discharge from the anal canal. patients with anastomotic fistula after Parks surgery are prone to stiff anastomotic stenosis due to a previous local infection, resulting in poor defecation function, and continuous daily postoperative dilation is required to prevent anastomotic stenosis. In patients with severe loss of continuity of the colonic dissection and anal canal, lifelong rerouting may be required.
(iv) Colonic transanal pull-out (modified Bacon procedure)
It is now believed that defecation reflex receptors are present not only in the lower rectum but also in the levator ani, puborectalis, and anal sphincter muscles. The modified Bacon procedure, like the Parks procedure, leaves the levator, puborectalis, and anal sphincter intact. After 3 months to 6 months of surgery, the patient gradually feels the urge to defecate. Through anal contraction exercises, the anal sphincter contracted strongly and the anal function recovered well. This is the theoretical basis for performing the modified Bacon and Parks procedures.
The modified Bacon operation was pioneered by Professor Zhou Xigeng, the founder of anorectal surgery in China, since the 1960s and has been improved for many times, and matured and perfected through a lot of clinical practice by Chen Xiangui, an anal preservation expert and former director of Zhejiang Cancer Hospital. From the beginning of the procedure to its perfection, it has been about 30 to 40 years, during which Chinese people have accumulated rich and unique clinical experience, and the level of understanding of anal preservation surgery is much higher than that of European, American and Japanese countries, thus we call modified Bacon procedure as the Chinese developed and perfected anal preservation surgery for rectal cancer, and we should rightly pay tribute to these experts.
The scope of the Modified Bacon procedure is the same as that of the Parks procedure, but the only difference is that the Modified Bacon procedure does not perform anastomosis but directly drags the colon section out of the anus without a protective enterostomy. The basic principle of the modified Bacon procedure is to free the rectum to the upper edge of the surgical anal canal (or lower), cut the specimen with an ultrasonic knife at the upper edge of the surgical anal canal, and the perineal team uses the ultrasonic knife to remove the mucosa above the dentate line (or burn the mucosa above the dentate line with an electric knife spark) and pull the colon out through the surgical anal canal, with the extra-anal colon acting as a temporary fecal diverter without the risk of anastomotic fistula, and then pulling the colon out after the procedure The extra-anal colon is used as a temporary fecal diverter without the risk of anastomotic fistula, and then the extra-anal colon is removed after natural healing with the pelvic and surgical sheaths. After removal of the extra-anal colon, the free edge of the colon will shrink to 4-5 cm from the anus and become stenosed, and the stenosis of the free edge of the colon leads to defecation dysfunction, which is the main reason and misunderstood by many doctors. The attending surgeon must teach the patient himself or his family to use an anal dilator to dilate the anus every day, and insisting on six months will completely solve this problem.
In the 21st century, with the emergence of laparoscopy and ultrasonic knife, it has brought a technical revolution to colorectal cancer surgery. Dr. Ping Huang of the First Affiliated Hospital of Nanjing Medical University kept pace with the times and overcame difficulties by applying laparoscopic technology to modified Bacon operation, which made the large abdominal incision significantly smaller or incisionless, greatly reducing patient trauma and improving the shortcomings of this operation.
(v) Intersphincteric resection (ISR)
The Parks procedure or modified Bacon procedure is generally performed by the abdominal group through the abdomen between the lower part of the tumor and the surgical anal canal to remove the specimen, while the ISR is performed by the perineal group through the dentate line or the white line between the internal and external sphincters and the abdominal group to remove the specimen. Therefore, ISR is more extensive than Parks or modified Bacon, and is suitable for stage T1-2 rectal cancer or rectal villous adenoma 2-6 cm from the anus.
There are two methods of ISR: (i) partial internal sphincterotomy with upward resection through the dentate line. (2) Total internal sphincterotomy with upward resection through the white line (the white line is located in the middle between the dentate line and the anus). In order to facilitate the operation, Japanese and Korean surgeons suspend the anus and make an internal sphincter underneath the tumor, and generally use the transwhite line (the white line is located in the middle between the dentate line and the anus) to free a certain range of internal sphincter upward in the gap between the internal and external sphincters, and then use Alice clamp to hold the broken end of the internal sphincter of the intestine, and continue to free upward and meet with the abdominal group by the tactile guidance of the fingers to complete the total internal sphincterotomy. In contrast, in China, Song Huayu, Zuo Zhigui and Xu Chang of the Department of Anorectal Surgery of the First Affiliated Hospital of Wenzhou Medical College used sutures to suspend the anus and then made an internal sphincter below the tumor, and after freeing a certain range upward through the dentate line at the internal and external sphincter gap, they placed a PPH anoscope to expose the anal sphincter, closed the severed end of the internal sphincter of the intestinal canal again under the PPH anoscope, continued to free upward to the pelvis to meet with the abdominal group, and completed partial internal sphincterotomy. The ISR separation method at the First Affiliated Hospital of Wenzhou Medical College in China is performed under direct vision, which should be superior to the Japanese and Korean palpation-guided ISR separation methods.
As patients have different lengths of anal sphincter, different lengths of PPH anoscope are required. Dr. Ping Huang of the First Affiliated Hospital of Nanjing Medical University has developed a retractable anoscope to fill the gap at home and abroad and provide a powerful tool for ISR.
The reconstruction of ISR is somewhat similar to the Parks procedure, in which the colon is anastomosed with the white line of the anal canal or the dentate line by hand sutures, and the possibility of anastomotic fistula exists in ISR as in the Parks procedure, so a protective ileostomy is required during the procedure. For this reason, Dr. Ping Huang has modified ISR by pulling the colon out through the anal canal during ISR and then removing the excess colon outside the anus after one month, without the need for a protective ileostomy and without fear of anastomotic fistula.
Because ISR removes part or all of the internal anal sphincter, which is smooth muscle. Patients may have poorly occluded anus during nighttime sleep, and there is a possibility that stool may spill out of the anus and contaminate the underwear at night.
(vi) APPEAR (Anterior Perineal PlanE for Ultra-low Anterior Resection of the Rectum, trans-anal perineal surgery)
In 2006-2008 Murphy J and William NS reported on the anterior perineal procedure, which is characterized by the technique of making an arc incision through the anterior perineum and freeing upward between the external anal sphincter and the transverse perineal machine with pelvic penetration; due to and removing the specimen through this incision, the anastomosis is completed. This procedure is more advantageous in coloanal canal ultra-low double anastomosis because it releases the longer intestinal canal above the anus.
The incidence of anastomotic fistula is high in ultra-low anastomoses, and the possibility of anastomotic fistula also exists after APPEAR surgery. once anastomotic fistula occurs after APPEAR surgery, perineal skin incision fistula may occur, which causes a lot of pain to the patient and adds a lot of work and problems to the bedside surgeon. In order to prevent anastomotic fistula, a protective ileostomy must be done at the same time of APPEAR surgery.
(vii) Transanal rectal cancer local excision
Early rectal cancer generally refers to rectal cancer located within the submucosa, and the possibility of lymphatic metastasis in rectal cancer infiltrating the submucosa is about 7%. The late Professor Zhou Xigeng of Shanghai Ruijin Hospital and his disciple Professor Yu Baoming of former Shanghai Ruijin Hospital, the founders of anorectal surgery in China, have strictly stipulated the indications for local resection of rectal cancer: (1) the tumor is confined within the submucosal layer; (2) the tumor is an elevated lesion; (3) the rectal adenocarcinoma is highly or moderately differentiated; (4) the diameter is <3 cm; (5) the tumor is within 7 cm from the anus.
Previously, transanal rectal tumor local excision was difficult to operate; with the application of suitable anal pulling hook (sometimes PPH anoscope can be used) and ultrasonic knife, the surgical field becomes clear and the operation becomes smooth.
(H) Trans-posterior anal sphincterotomy (Mason’s operation)
In 1970, Mason invented transanterior abdominal and combined trans-posterior external anal sphincterotomy for rectal cancer resection, which required changing the position during the operation, in addition to transverse colostomy to protect the healing of the anastomosis. The indications for Mason’s surgery are similar to transanal rectal resection, but it is also suitable for local resection of rectal villous adenoma, rectal mesenchymal tumor and rectal carcinoid tumor, but with the development and promotion of TAMIS, Mason’s surgery will give way to TAMIS. However, with the development and promotion of TAMIS, the Mason procedure will give way to the TAMIS procedure.
I believe that Mason surgery is more suitable for resection of masses around the lower rectum, and I know that: 1) In Mason surgery, the patient is placed in prone position, and the incision is made from above the sacrococcygeal joint to the anal verge, which is fully exposed and easy to operate. After cutting the external anal sphincter, the internal anal sphincter can be further cut as needed. ②After the external anal sphincter is cut, intermittent counter sutures with absorbable thread are used, and the sutures should not be partial, usually 5 to 6 stitches are needed to restore the anal throttle function. (iii) The caudal bone can be removed without resection or resected. After caudal bone resection, the caudal bone defect is prone to fluid accumulation and infection. The posterior subcutaneous tissue and skin of the tailbone defect can be left unsutured, and it is safer to change medicine and drainage directly with gauze strips every day and to change medicine until the incision heals. If there is a rectal wall or internal sphincter incision, a protective enterostomy is recommended to prevent fistula.
(ix) TAMIS (transanal minimally invasive surgery)
TAMIS (transanal minimally invasive surgery) was first reported and named by Dr. Atallah in 2010. It is a transanal minimally invasive surgery in which a single-hole laparoscopic channel (soft trocar, also known as SpongeBob SquarePants) is placed into the anal canal and a conventional laparoscopic instrument is used to complete local excision of rectal tumors through the anal route. Wang Jianping and Kang Liang of the Sixth Hospital of Sun Yat-sen University in Guangzhou and Shen Zhanlong and Ye Yingjiang of the People’s Hospital of Peking University were the first to perform and promote TAMIS in China.
TAMIS can not only perform local resection of benign rectal tumors and early malignant tumors, but also has been used to complete total mesorectal excision (TME) for progressive rectal cancer with laparoscopy in recent years, and even TAMIS has been reported to complete transanal TME (taTME) independently, namely TAMIS-TME procedure. It can be seen that the application of TAMIS not only promotes and popularizes the minimally invasive transanal surgery for local resection of rectal tumors, but also brings a new perspective to the anal preservation surgery for progressive rectal cancer.
Current indications for TAMIS: ①The scope of application is generally the local excision of benign rectal tumors (rectal adenoma, rectal carcinoid tumor, rectal mesenchymal tumor) within 10 cm from the anal verge and less than 3 cm in diameter and early stage T1 rectal cancer. ②In laparoscopic rectal cancer anus-preserving surgery, the method can be applied adjuvantly to free and converse the tumor specimen upward through the anus, complete TME, remove the specimen, reduce the difficulty of anus-preserving surgery, and increase the reliability, radicality and safety of anus-preserving surgery.
Since the current single-hole laparoscopic channel (soft trocar, also known as SpongeBob SquarePants) is a disposable medical product produced in the United States, the cost is more than 10,000 RMB. In China, there is the use of PPH anoscope combined with gloves to complete TAMIS, which greatly reduces the cost of equipment. Dr. Ping Huang of the First Affiliated Hospital of Nanjing Medical University has developed a retractable anoscope, and TAMIS can be completed with the help of retractable anoscope or retractable anoscope combined with sterile gloves, which is more convenient than SpongeBob application, greatly reduces the cost, fills the gap at home and abroad, and provides a powerful tool for the development of TAMIS. It is believed that TAMIS will be widely used in China soon.
(X) laparoscopic rectal cancer anal preservation surgery
At the end of the last century, laparoscopic rectal cancer surgery was carried out sporadically in large hospitals in Shanghai, Nanjing, Chengdu, Guangzhou, etc. At that time, ultrasonic knife was not yet applied, which limited the promotion of laparoscopic rectal cancer surgery. At the beginning of the 21st century, with the development and promotion of ultrasonic knife and laparoscopic instruments, laparoscopic rectal cancer surgery was in the ascendant. Laparoscopic rectal cancer surgery has formed a complete routine and was soon accepted by everyone, and it is much more convenient for the operator to operate.
With the exploration, accumulation, exchange and popularization of laparoscopic techniques, open surgical operation techniques can basically be used under laparoscopy, and any kind of anus-preserving surgical methods such as double anastomosis, transanal turn-out resection, Parks, modified Bacon’s operation, ISR, APPEAR, TAMIS can be carried out or combined under laparoscopy.
Laparoscopic anus-preserving surgery for rectal cancer has made surgical operations clearer and simpler, with significantly less trauma and faster recovery for patients. Laparoscopic anus-preserving surgery for rectal cancer has become an unstoppable trend, universally accepted by patients and surgeons, and is covering the surgical table with an accelerating trend.