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Introduction
As screening has substantially increased the early diagnosis of tumors, there is a need for local treatments that are oncologically equivalent to radical surgery, but safer and functionally superior.1 Local excision of rectal tumors has been performed since early 1800, when Lisfranc described a local resection for rectal carcinoma.2
Transanal endoscopic microsurgery (TEM) was described initially by Gerhard Buess in 1983 to provide a means for removing benign lesions of mid and upper rectum not easily accessible by conventional methods.3
Compared to local excision, TEM provides superior quality of resection, decreased local recurrence, and improved survival, particularly among patients with adenomas4 and histologically favorable stage I rectal cancer.3,5 In long-term follow-up, TEM excision of rectal tumors has proven to be safe and effective, with morbidity and mortality similar to that of conventional transanal excision.6,7
However, although TEM has been in use for more than 20 years, it has been slow to become universally adopted by colorectal surgeons, partly due to a long learning curve, but also because of the significant cost of the highly specialized equipment.2-4
As technology continues to undergo rapid evolution, the minimally invasive surgeons' skills develop quickly. Recently the Natural Orifice Transluminal Endoscopic Surgery (NOTES) has provided technology for developing permanent and disposable equipment and instruments that can be used for both abdominal and pelvic operations through a single incision. These devices have facilitated a wide range of operations, including bariatric and all sorts of colorectal surgeries using a single-incision mutiport device.
The working angles in single-access laparoscopy are essentially identical to those used in TEM. Therefore, crossover exists between the skill set necessary to perform single-port laparoscopy and TEM. The considerable upfront cost of TEM instrumentation, however, remains a significant barrier to its widespread use.
Transanal minimally invasive surgery (TAMIS) has been described first by Dr. Attalah, Dr. Larach and Dr. Albert, from Orlando, FL,3 who reported this technique to be effective and safe for early rectal cancer and adenomas, with excellent operative field visibility and not technically difficult. As the authors say, the TAMIS is a "giant leap forward" when compared to TEM. Mounting is easier and demands less time prior to beginning surgery; as it is a disposable device, the cost is much lower and manipulation is much more comfortable than TEM.
Recently, Ethicon™ (Cincinnati, OH) presented their Single Site™ (SSL) device for NOTES. It has been designed for single-incision laparoscopic abdominal surgeries, but has been also used successfully for TAMIS resection.8 A little later, GelPoint Path™ has been launched by Applied Medical (Rancho Santa Margarita, CA), specifically for TAMIS.
Methods
Over a 24-month period TAMIS has been offered to all patients with rectal lesions who were candidates for transanal local resection or abdominal anterior resection when carcinoma was excluded. Informed consent was obtained and all patients were given the option to undergo conventional surgery. Patients with known malignant lesions were excluded.
From August 2010 to August 2013 all data of patients undergoing this surgical technique, using both SSL™ and GelPoint Path™, was collected prospectively. Follow-up was for up to 24 months. All patients had digital rectal examination or colonoscopy postoperativelly. Patients undergoing the technique of TAMIS patients had adenomas with dysplasia of low and high grade, only one of them had a scar after incomplete endoscopic resection, and one as adenocarcinoma in situ. Patients having previous diagnosis of adenocarcinoma underwent transrectal ultrasound to evaluate depth and nodal invasion.
Surgical procedures were performed at a tertiary-care Hospital. All patients were administered general anesthesia. To perform the procedure the patient's preferable position is one in which the lesion is in the rectum wall that is closer to the operating table. When the lesion is in the posterior rectal wall, the patient is in lithotomy position, with legs up; when the tumor is in the right lateral wall, the patient can be turned with the right side down. Although not mandatory, this is the most comfortable way to perform this procedure. Mechanical bowel preparation was administered preoperatively and received a single 3 g-dose of intravenous Unasyn® (Pfizer, Brazil), at anesthetic induction.
After insertion of the transanal port (either the SSL™ or GelPoint Path™, Fig. 1), the pneumorectum was gained using CO2 insufflation with an initial pressure set a 12 mmHg and flow set at 40 mmHg per minute. Standard straight laparoscopic instruments were used. Full-thickness excision was performed on all lesions aiming a 1 cm minimum negative margin (Fig. 2). All defects were closed completely with absorbable suture material (Fig. 3).
Patients had a planned discharge for the next day of surgery.
Results
Eleven patients aged 50–86 years (average 67.4 y) underwent TAMIS resection of rectal lesions (Table 1). The average distance from anal verge was 47.7 mm (15–80 mm) and the mean tumor diameter measured by pathology was 35 mm (10–60 mm). Eight patients had an initial diagnosis of adenoma. One patient had a previous endoscopic resection of a T1 adenocarcinoma (case C), made with mucosectomy technique and had positive margins. This patient was eligible for scar resection with larger margins. No tumor was found by the pathologist in this patient.
Table 1 Tumor characteristics.
| Case, age/sex | Tumor location (mm from anal verge) | Initial tumor pathology | Position | Tumor diameter (mm) | Resection margin | Final tumor pathology |
|---|---|---|---|---|---|---|
| A, 51/M | 15 | Vilous adenoma | Posterior | 30 | Free | Adenocarcinoma T1 |
| B, 76/M | 25 | Vilous adenoma | Left lateral | 50 | Free | Tubule-vilous adenoma |
| C, 50/F | 40 | Adenocarcinoma T1, ressected with endoscopic mucosectomy, focally compromised margins | Left lateral (no visible tumor, only scar) | 20 (scar) | Free | Free from tumor |
| D, 63, F | 10 | No AP inicial | Left posterior | 20 | Free | Free from tumor |
| E, 78/M | 60 | Tubule-vilous adenoma | Posterior | 60 | Free | Adenocarcinoma T2 |
| F, 81/M | 50 | Tubulo-vilous adenoma, high grade dysplasia | Circumferentiala | Circumferential | Partially resected | Tubulo-vilous adenoma |
| G, 66, F | 30 | Vilous adenoma | Right posterior | 50 | Free | Tubulo-vilous adenoma |
| H, 86, F | 40 | Vilous adenoma | Right posterior | 50 | Positive | Adenocarcinoma Tis |
| I, 52, M | 10 | Tubule-vilous adenoma | Anterior | 40 | Not resected (a) | |
| J, 65, M | 50 | Vilous adenoma | Left posterior | 40 | Positive | Adenocarcinoma Tis |
| K, 74, F | 80 | Adenocarcinoma in situ | Anterior | 40 | Free | Vilous adenoma |
aAfter positioning the patient the device could not be positioned and the technique was changed to standard local resection.
One patient (case D) could not be operated by the described technique. Expansion of the SSL™ retractor into rectal lumen was not possible. The size of the prostate occupying the rectal lumen was probably responsible for not allowing the device to open toward the anterior rectal wall and thus a conventional local excision was used instead.
Another patient (case F) was under evaluated during preoperative colonoscopy, as the tumor was described as lateral, and during surgery it showed as circumferential. In this case it was resected partially, only for ensuring pathologic diagnosis, and further taken to laparoscopic anterior resection with colonic pouch-anal anastomosis. Pathologic specimen showed tubulo-vilous adenoma.
Setup time varied from 1 to 45 min (average 9.8 min), and total surgery time was from 38 to 80 min (average 51 min). Two of the ten resected specimens contained early stage adenocarcinomas. All margins were free (Table 2).
Table 2 Clinical and operative results.
| Case | Operative time (min) | Hospital stay (days) | Morbidity/mortality |
|---|---|---|---|
| A | 55 | 1 | None |
| B | 50 | 1 | None |
| C | 45 | 1 | None |
| D | 45 | 1 | None |
| E | 80 | 1 | None |
| F | 40 | 1 | None |
| G | 47 | 1 | None |
| H | 60 | 1 | None |
| I | Not performed | Not operated | None |
| J | 50 | 1 | None |
| K | 38 | 1 | None |
Once the resection was completed, the defect was approximated with intraluminal suture. In nine patients the option was to place metallic clips on both edges of the suture, instead of tying. One patient had ties done on the suture's edges.
All patients stayed overnight and were discharged the next morning.
As the only known complication, one patient had a partial dehiscence of the suture line in distal rectum diagnosed on ninth post-operative day, and was treated without surgical re-intervention. In this patient, scar completion took about 45 days.
Discussion
Although TEM has been proven to be an effective alternative for local excision and is being performed for more than 30 years, which is before the widespread use of laparoscopic techniques for abdominal surgeries, the advancements in the TEM technique remained almost the same and did not follow what happened to abdominal laparoscopy. Before TAMIS was presented in 2010, the only evolution in transanal surgery was the development of rigid metal or transparent9 proctoscopes for TEM. When TAMIS was first described, the world became aware of a completely new technique using an affordable, simple, easy-to-use and effective device.
Care must be taken in patient selection, as local excision must be considered only for early rectal cancer with no evidence of nodal metastasis,5,10 parameters that can be predicted by clinical and radiological evaluation.11,12 Even after adequate pre-operative evaluation, up to 44.3% of T1 tumors can be misevaluated pre-operatively.1,13 Although all patients were submitted to surgery with a tumor thought to be benign, one had a T1 and the other a T2 tumor. As oncological safety for local resection for T2 tumors is not well stablished,1,14-17 this last one was further taken to laparoscopic anterior resection with colo-anal anastomosis and pathology showed no residual carcinoma or positive lymphnodes (pT0 N0) in the surgical specimen.
A tip to be learned is that the prostate volume should be evaluated pre-operatively, as it can be limiting for the technique.
Considering the minimal setup time, low cost and specially the adaptation of regularly used laparoscopic instruments, TAMIS provides an ideal platform for transrectal or transanal resection.18 It has also been used for other diseases, such as high fistulas and distal rectal mobilization for coloanal anastomosis19 and carcinoid tumors resection.20,21 Other indications that lack consensus are re-excision following endoscopic removal of malignant polyps22 and excision of downstaged tumor or scar after complete response to neoadjuvant chemo/radiotherapy.13,23-25 Recently, total mesorectal excision performed by TAMIS showed to be feasible and promises good future results.
In this series, maximum distance from tumor to anal verge was 8 cm. This patient had a 5 cm diameter tumor, so resection was up to 14 cm from anal verge, considering margins, without difficulties, showing that its use must not be restricted to low tumors, as suggested before.26
The advantages of TAMIS over TEM are well described:3,27
Devices used for TAMIS are pliable and allow well-fitted positioning at the anal canal, possibly leading to less impairment of sphincter function than the 40 mm rigid scope used for TEM.
Setup time is significantly lower for TAMIS.
Possibility to use regular straight laparoscopic instruments and a standard 30° laparoscope, as opposed to the fixed eyepiece of the TEM rectoscope, which enables advancement of the scope into the proximal rectum and sigmoid, thereby allowing the surgeon to look beyond the tumor.
It can be easily learned by surgeons not used to TEM technique due to its potential instrumental simplicity and similarity with conventional laparoscopic surgery. Larger ports, up to 15 mm port are available only for TAMIS devices, and it can be very helpful when a 12-mm stapler is needed (e.g. for safe resection of a big pedunculated polyp).
Cost makes SSL™ and GelPoint Path™ very comfortable, safe and cost-effective alternatives for TEM.28 When abdominal resection is considered for adenomas or T1 tumors that are from dentate line up to higher rectum, or even if future studies show that selected T2 and T3 tumors can be locally controlled,1,14,16,29 TAMIS devices can be a remarkable cost-effective alternative.
The cap can be removed and re-located quickly, when needed. It can be removed for specimen retrieval and repositioned in less than 1 min for suturing.
Positioning the device takes usually less than 1 min.
Due to its design, there is no need for investment in special curved instruments. All regular laparoscopic instruments can be used.
The repositionable cap allows changing of instrument position without having to reinsert the device.
As the devices are basically a hollow sleeve with a cap in which the ports are located, there is no resistance when moving around the instruments. This makes the use of regular straight laparoscopic instruments easier than TEM or SILS™ (Covidien, Mansfield, MA).
Conclusions
Although at present time the appropriate use of local excision is still under debate, TAMIS is a technique that has a potential of increased application and much remains to be learned. Like others,3,27 our group is optimistic that TAMIS came as a good alternative to TEM and also as one of the most important contributions for transanal surgery in the last decades years. Its reduced cost and simplicity shall allow surgeons to learn the technique quite easily. Despite simplicity, care must be taken in patient selection, as pre-operative staging is frequently an understaging of tumors.
