Transanal Minimally Invasive Surgery

Transanal minimally invasive surgery (TAMIS) was first reported in 2010 by Sam Atallah from Florida.[¹] It quickly gained popularity due to its simplicity of technique and cost-effectiveness. Although Trans Anal Endoscopic Microsurgery (TEM) was described in 1984 by Dr Buess from Germany it didn't gain that wide acceptance because of the complexity of the instruments and long learning curve.[²³] Atallah used SILS™ port which was intended and used for SILS procedure for abdominal operations. I would say that the development of SILS technique paved a way for TAMIS. It developed as an unintended advantage for laparoscopic colorectal surgeons. It is in true sense a NOTES surgery.[³]

We have been doing TAMIS at Sir Ganga Ram Hospital since September 2016.[⁴]

We started with SILS (Covidien) port. Subsequently when the operation theatre (OT) committee was convinced about its safety and feasibility, we procured our first GelPOINT® Path (Applied Medical, Rancho Santa Margarita, California, USA), which is specifically designed for TAMIS.

The following are the basic steps for a successful TAMIS operation.

STEP 1: FULL PREOPERATIVE WORKUP AND PATIENT SELECTION

Any patient who is considered for TAMIS should have a colonoscopy with biopsy. The lesion preferably should be within 12 cm from the anal verge. Biopsy should be favorable, which means it should be an adenoma, a carcinoma in situ, or well-differentiated adenocarcinoma, which is superficial.

A preoperative endorectal ultrasound or magnetic resonance imaging pelvis should be done to make sure that the lesion is either Tis or at the most T1, and there should be no suspicion of nodal involvement or lymphovascular invasion [Figure 1]. Ideally, the size of the lesion should be 3 cm or less and should not occupy more than 1/3^rd of the rectal circumference.[²⁵]

Figure 1: Magnetic resonance imaging of rectal adenoma with carcinoma in situ

STEP 2: PATIENT COUNSELING AND BOWEL PREP

Once it is established that TAMIS needs to be done, the patient should be counseled about the procedure and informed that after TAMIS, if biopsy results turn out adverse, then a full rectal resection is indicated. We do not perform frozen routinely. We believe in wide local excision and sending the specimen for proper histopathological examination. We advise full bowel prep with one day prior clear liquid diet. Our preferred regimen is 4 L of split dose polyethylene glycol.

STEP 3: CHOICE OF ANESTHESIA AND PATIENT POSITIONING

General anesthesia is preferred although it can be performed under spinal or epidural anesthesia. The patient is placed in lithotomy position [Figures 2 and 3]. A Foley's catheter is inserted to decompress the urinary bladder. Sequential compression devices are used for deep-vein thrombosis prevention.

Figure 2: Lithotomy position with SILS port

Figure 3: GelPOINT Path transanal minimally invasive surgery platform

STEP 4: CHOICE OF TRANSANAL MINIMALLY INVASIVE SURGERY PLATFORM AND INSTRUMENTS

Both SILS port and GelPOINT Path can be used to perform TAMIS. It depends on the availability and personal choice of the surgeon. Before inserting the platform, a digital rectal examination is performed and usually some form of anal dilation is needed. GelPOINT Path has an anal dilator provided with it. We recommend using Lone Star retractor prior to the insertion of the platform as it makes subsequent platform insertion easy and keeps the anal verge retracted in case of conversion to the conventional transanal procedure is considered.

Although curved instruments specifically designed for TAMIS are available in the market, we do not use them and have found conventional laparoscopic instruments sufficiently efficient for TAMIS. The most common instruments used are a laparoscopic hook with monopolar cautery, a bowel grasper and laparoscopic suction, and a needle holder.

STEP 5: OPERATION THEATRE SETUP

The surgeon stands in between the legs of the patient with the assistant showing camera by the side. A scrub nurse can stand on the other side or behind the surgeon. The screen is positioned at the head end of the patient.

STEP 6: DISSECTION

Carbon di oxide is connected to the platform, and pneumorectum is created with pressure in the range of 8–15 mmHg. We prefer 15 mmHg. There is a problem of rectal billowing which occurs annoyingly if a conventional SILS platform is used. There are two solutions to this. One is the reservoir bag which comes with the GelPOINT Path at no additional costs. It eliminates the pulsation, but smoke is still an irritant which needs repeated egress through the side valves. Another option is to use AirSeal^® continuous airflow. Once pneumorectum is created, a 5mm 30 degree is used to assess the rectal lesion. Monopolar hook electrocautery is used to score around the lesion at least 1 cm away from the margins of the lesion [Figure 4]. Once scoring is done, a full-thickness rectotomy is made till perirectal yellow fat appears [Figure 5]. This is usually a blood-less dissection with mono polar energy enough to coagulate minor bleeders. Dissection is carried out circumferentially, and the specimen is handled carefully with a bowel grasper and careful consideration is made not to fragment it. Once fully dissected out, the specimen is removed by removing the SILS port or the cap of the GelPOINT Path and placed on a piece of a surface than can be pinned with a needle (e.g., thermocol and cardboard). And, its edges are pinned down with a 22G needle [Figure 6]. This step should be done first by the surgeon before proceeding with the next step of TAMIS.

Figure 4: Scoring lesion

Figure 5: Dissection exposing perirectal fat

Figure 6: Oriented specimen

STEP 7: CLOSURE OF DEFECT

The rectal defect is closed with 3-0 braided absorbable suture in a running fashion [Figures 7 and 8].

Figure 7: Closure of the rectal defect

Figure 8: Final picture

The defect can be left open also depending on the surgeon's choice. We prefer to close it. The site is inspected for hemostasis. The TAMIS platform is removed, and the Lone Star retractor is removed. A light pyramid-shaped dressing is done over the anus. We do not use any anal packing.

STEP 8: POSTOPERATIVE CARE AND DISCHARGE

Analgesics are given per protocol. Usually, TAMIS is a well-tolerated procedure. We begin soft diet the same day, and the patient is discharged after a few hours or the next day if done late in the evening. Normal diet is resumed the next day. We do not recommend any laxatives.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.