Transanal minimally invasive surgery - A single-center experience : Journal of Minimal Access Surgery

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Original Article

Transanal minimally invasive surgery - A single-center experience

Pangeni, Anang; Imtiaz, Mohammad Rafiz; Rai, Sujata; Shrestha, Ashish K; Basnyat, Pradeep Singh

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Journal of Minimal Access Surgery 19(1):p 35-41, Jan–Mar 2023. | DOI: 10.4103/jmas.jmas_390_21
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Transanal minimally invasive surgery (TAMIS) was described in 2010, as a hybrid to transanal endoscopic microsurgery (TEM)[1,2] for local excision of the rectal lesions. Over the last few years, its use has been extended to more anorectal pathologies such as fistula-in-ano, recto-vaginal/-urethral fistula; modified or improvised for procedures such as foreign-body removal, control of rectal bleeding, J-pouch excision and has further evolved to robotic-TAMIS and transanal total mesorectal excision.[3-6]

The rise in the adoption of TAMIS is mostly due to its versatility, transfer of laparoscopic skill without a need to face an entirely new learning curve, relatively low cost and the use of already available, familiar surgical instruments. Although it has seen much progress and evolution, it is still a complex surgery and has a significant learning curve.[7,8] The data on clinical outcomes, including patient quality of life assessment, are still growing.[6,9] The morbidity associated with TAMIS is low.[10,11]

This study aimed to assess the outcomes of TAMIS in a district general hospital performed by a colorectal surgeon for rectal pathologies.


A retrospective study on prospectively collected data on 52 consecutive patients of TAMIS between the period of May 2014 and February 2020 was conducted. Data were collated from electronic health records, multi-disciplinary meeting minutes (action sheets), Unisoft and cross-reference from the surgical logbook and histological data.

Patients with large rectal polyps deemed unsuitable for colonoscopic removal were offered TAMIS. Appropriate imaging modalities such as computed tomography scan of the chest, abdomen and pelvis as well as magnetic resonance imaging rectum/pelvis were performed for staging. It is a standard practice of the unit to discuss all suitable cases in the colorectal multidisciplinary team (MDT). Patients were followed up at 3 and 6 months and continued thereafter as per post-polypectomy British Society of Gastroenterology guidelines.[12]

We assessed the data on operative time, length of stay (LOS), post-operative morbidity and resection margins.


All patients were fully counselled for the procedure and received Moviprep® as full bowel preparation before the operation. The procedure is performed under general anaesthesia in the lithotomy position. A Foley catheter is inserted before surgery and removed immediately on the completion of the procedure. All patients received one dose of antibiotics as recommended by the trust (Co-amoxiclav, 1.2 g) followed by 5 days of oral metronidazole (400 mg three times daily).

Standard thrombo-prophylaxis with a single dose of enoxaparin and thrombo-embolus deterrent stockings was provided to all patients. An extended thrombo-prophylaxis for 7 days was considered in selected high-risk cases as recommended by the NICE guidelines.[13] A thorough examination of the anoretum was then performed.

We use GelPOINT® access platform (AppliedMedical, California) for all patients [Figure 1]. A camera port and two working ports are inserted in the GelCap at 11, 7 and 5 o’clock position, which is then mounted to the platform. Create pneumo-rectum at 12–14 mmHg using Ethicon® insufflator. A 30°, 5 mm telescope is used to visualise and identify the lesion [Figure 2]. A 5mm 30° camera, grasping forcep and hook monopolar diathermy is used for dissection. The pressure was set between 12 and 14 mmHg. More recently, with the COVID-19 pandemic, the availability of the smoke extractor system AirSeal® (Conmed, NY, USA) has made a significant difference in picture quality, smoke extraction and speed of surgery and safety to theatre staff.

Figure 1:
GelPoint platform. A camera port and two working ports are inserted into the platform. Please note silk sutures hold the platform in place, one insufflating channel for pneumorectum and the other channel can be connected to AirSeal for smoke evacuation (at 30’clock position, unused in this image)
Figure 2:
Endoscopic view of a sessile polypoid lesion on the left anterolateral wall of the rectum

The lesion is marked circumferentially using a diathermy hook taking care to leave adequate margins in all directions [Figure 3]. Then, the lesion is dissected full thickness taking adequate depth [Figure 4]. The specimen is then extracted, removing the gel cap and placed on a sponge, oriented, marked and sent for histopathological examination [Figure 5]. All defects are closed with v-lock or Vicryl Rapide™ (polyglactin) 2.0/3.0 sutures 45 mm needle [Figure 6]. Patients with lesions close to the dentate line receive bilateral pudendal nerve block with 0.5% 10 ml Chirocaine infiltration for post-operative analgesia.

Figure 3:
Delineation of margin of excision around the lesion using hook diathermy
Figure 4:
Full thickness dissection being carried out following the markings at the margin. Please note the perirectal fat at the depth
Figure 5:
The specimen
Figure 6:
The defect is being closed using V-lock suture transversely

Patients are discharged home the same day with safety netting advice. Only those patients with a long procedure or multiple comorbidities or unsuitable for discharge on anaesthetic team review were admitted for overnight stay.


A total of 52 patients, 21 males and 31 female, underwent TAMIS between May 2014 and February 2020. The median age was 69 years (38–84) and the median body mass index was 29 (22–42). Table 1 summarises the demographics and clinical variables.

Table 1:

Most of the procedures were scheduled elective operations and were discussed at colorectal MDT before scheduled for the TAMIS. In one of the patients, an urgent TAMIS was necessary for the inability to control bleeding at attempted colonoscopic polypectomy. Majority of the patients had rectal polyp or growth identified at colonoscopy and referred to the colorectal team for TAMIS because of large size or recognition that they are more suitable for TAMIS than endoscopic resection. A repeat TAMIS was needed in four patients.

Of the 58 attempted TAMIS in 52 patients, two cases had to be abandoned, amounting to a success rate of 96.5%. Both were in the early years of our experience. In one, the procedure was abandoned after establishing the pneumorectum where the lesion was found to be fixed to the lateral wall. Multiple biopsies were taken on the day, and subsequently, the patient underwent successful laparoscopic standard abdomino-perineal resection after 12 days. The final diagnosis was pT3 adenocarcinoma. In the other, an adequate pneumorectum could not be created and the benign polyp was later excised by sigmoidoscopy and polypectomy. We have had no cases abandoned for TAMIS since 2016.

Four patients needed to redo TAMIS. The first patient was for the completion of resection following successful emergency TAMIS haemorrhage control. Three other patients needed redo TAMIS for polyp at the TAMIS site on follow-up.

The median distance of the lesion from the anal verge was 6 cm. The most distal lesion was at 3 cm and the proximal at 10 cm from the anal verge. The lesions closer to the dentate line pose more challenges than mid-rectal lesions due to difficulty in placing the Gel point platform. Where multiple polyps were removed, the distance of the largest lesion was considered for calculation.

We performed all excisions on the lithotomy position irrespective of the site of tumour. Anteriorly located tumours are more tedious to operate on in our experience. However, with 30° camera, tumours at all locations can be well visualised and excised.

The median largest dimension of the excised lesion was 30 mm (10–60 mm). In the majority of the cases, the defects were closed using a V-Lock suture or for very near and small lesions, Vicryl Rapide 2/0 interrupted sutures were used.

The median operative time was 55 min (8–175 min) and this was gradually reduced with increasing experience. The operative time was calculated after placement of the platform to the last suture for closing the defect, hence provides a more realistic/accurate surgical time. Table 2 summarises the operative findings.

Table 2:
Operative summary

In our study, we had no intraoperative inadvertent entry into the peritoneal cavity. Two patients needed Foley catheterisation postoperatively for urinary retention. There was no major haemorrhage needing transfusion or relook in the theatre [Table 3].

Table 3:
Post-operative details

The most common final diagnosis was tubulovillous adenoma with low-grade dysplasia (n = 30, 51.7%). Adenocarcinoma was noted in 10 (17.2%), of which 2 (3.5%) were focal non-invasive areas within dysplastic tubulovillous polyps. Of the eight invasive adenocarcinoma, 4 (50%), 2 (25%) and 2 (25%) were of T1, T2 and T3, respectively, in histopathology. One patient (1.7%) was found to have well-differentiated neuroendocrine tumour [Table 3].

All of the specimens were complete and without any fragmentation and all attempts were made intraoperatively to avoid piecemeal removal. At the time of excision, all had gross-negative margins. Out of 58 samples, the microscopic R0 resection margin was achieved in 45 (77.5%) samples. Six (10.3%) had microscopically positive margins. Of these, 3 of the patients had pT2 or pT3 adenocarcinoma with <2 mm microscopic margin and their outcomes are described in Table 4. Seven patients (12%) had indeterminate margins in the biopsy.

Table 4:
Outcomes of patients with the diagnosis of malignancy

Thirty-eight (73%) patients had TAMIS as a day case without the need for overnight admission. Ten (19%) patients stayed in the hospital overnight and were discharged home on day 1 post-operative. The patient who stayed for 3 days was the patient with post-colonoscopy bleed and he had undergone TAMIS as an emergency procedure. One patient stayed 4 days for social reasons (awaiting care package) [Table 5].

Table 5:
Length of stay


TAMIS has developed as a hybrid technique between TEM and laparoscopic surgery for the resection of rectal lesions. It is a platform easier and cheaper to set up as it uses locally available logistics. It provides local excision for suitable rectal lesions, thus avoiding more invasive and radical surgery. It is not only a safe and effective technique for treating benign and early rectal tumours but also provides good oncological and functional outcomes. The laparoscopic skills of the surgeon translate into the procedure without the need for acquiring new ones.[10]

Operating in a confined space is challenging and adjustments are definitely needed. Our experience shows that the operating time gradually reduces after a certain number cases/year of experience.

The success rate of TAMIS in our series is 96.5% which is similar to other reported literature. Caycedo- Caycedo-Marulanda, et al. reported a 100% success rate, although in some cases, they used hybrid techniques in addition.[14]

The pattern of lesions excised reflects that of similar literature published with adenomatous polyps in the majority. In our study, 44 (84.6%) patients had adequate resection margin (R0) and positive margin in 6 (11.5%) patients. Previous studies reported variable success rates ranging from 47% to 100%.[14-17] During the follow-up, we have noted that patients with polypoidal growth excised showed granulation tissues only.

In the majority (61.5%) of our patients, we successfully managed to perform this procedure as a day-case and only 33% of patients needed overnight admission. Our median LOS stay is 0 (0–4) which is less than the previously published studies.[14,17-19]

We experienced no peritoneal breach in any of the patients during the procedure. Notable is that only 20 of our cohort of patients had their lesion 8 cm or more from the anal verge. The median distance was 6 cm. Peritoneal breach is variably reported: 2% in Canadian experience that includes 50 patients[14] and around 5% in a recent series of 17 patients from Qatar.[20] One patient developed urinary retention after the procedure. There were no incidences of post-operative haemorrhage needing admission or repeat procedure.

In all of our patients, the raw area after excision was closed. A recent meta-analysis suggested that closure of the rectal defect after TAMIS/TEMS is time-consuming but can reduce the risk of post-operative bleeding. However, there are no significant differences in post-operative LOS or infection based on the closure of the defect.[21]

We follow patients with flexible sigmoidoscopy at 3–6 months and then annually thereafter, tailored according to findings and biopsy results. There were no recurrences in patients with adenocarcinoma. Of note, two of our patients with pT2 cancer did not accept further surgery. One patient was found to have a granulation tissue polyp and in the another, a tubulovillous adenomatous polyp, completely excised, was found in the follow-up. Recurrences of up to 8% have been reported.[14] We acknowledge that the number of patients in this series is small.


Our data suggest that TAMIS can be safely performed in a DGH for both benign and early rectal cancer. TAMIS was also able to control post-polypectomy bleeding and the completion of rectal polypectomy. In selected cases, day-case TAMIS is safe and feasible.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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Day-case; minimally invasive surgery; rectal polyps; transanal minimally invasive surgery

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