Surgical Endoscopy (2023) 37:9080–9088 and Other Interventional Techniques https://doi.org/10.1007/s00464-023-10448-5 Surgical treatment of retrorectal tumors: a plea for a laparoscopic approach Clara Galán1 · M. Pilar Hernández1,2 · M. Carmen Martínez1,2 · Anna Sánchez1,2 · Jesús Bollo1,2 · Eduardo Mª Targarona1,2 Received: 6 June 2023 / Accepted: 5 September 2023 / Published online: 5 October 2023 © The Author(s) 2023 Abstract Introduction Retrorectal tumors (RRTs) are rare and often surgically excised due to the risk of malignant degeneration and compressive or obstructive symptoms. The approach for excision has traditionally been based on tumor location and per- formed using either a transabdominal or perineal approach depending on the position of the tumor. The advent of minimally invasive surgery, however, has challenged this paradigm. Here, we determined the applicability and potential advantages of a laparoscopic transabdominal approach in a series of 23 patients with RRTs. Material and methods We included 23 patients presenting with RRTs treated at the Surgical Gastrointestinal Unit at Hospital de Sant Pau that were registered prospectively since 1998. The preoperative evaluation consisted of colonoscopy, CT scan and/or MRI, mechanical bowel lavage, and antibiotic therapy. Signed consent was obtained from all patients for a laparoscopic transabdominal approach unless the tumor was easily accessible via a perineal approach. In case of recurrence, a transanal endoscopic microsurgery (TEM) approach was considered. Surgical details, immediate morbidity, and short- and long-term outcomes were recorded. Results Of the 23 RRT cases evaluated, 16 patients underwent a laparoscopic transabdominal approach and 6 underwent a perineal approach. No patients required conversion to open surgery. In the laparoscopic transabdominal group, the mean operating time was 158 min, the average postoperative hospital stay was 5 days, and postoperative morbidity was 18%. Three patients had recurrent RRTs, two of the three underwent surgical reintervention. The third patient was radiologically stable and close follow-up was decided. Conclusion Our results show that laparoscopic transabdominal excision of RRT is a safe and effective technique, offering the potential advantages of less invasive access and reduced morbidity. This approach challenges the traditional paradigm of excision of these infrequent tumors based solely on tumor location and offers a viable alternative for the treatment of these infrequent tumors. Keywords Retro-rectal tumors · Laparoscopic transabdominal approach · Minimally invasive surgery · Perineal approach The retrorectal space is a potential site for infrequent types similar. Growth inside the lower pelvis may be followed by of histological lesions known as retrorectal tumors (RRT). local compressive or obstructive symptoms, which together Due to its embryological development, this virtual anatomic with the potential risk of malignant transformation neces- space joins several organs of varying histological origin [1, sitate resection [1–3]. 2]. Although the origin varies, clinical features of RRT are The classical rule of thumb for surgical excision is based on the location of the RRT. For tumors above an imagi- nary line crossing the pelvis at S2 or S3 sacral vertebrae a * Eduardo Mª Targarona Etargarona@santpau.cat transabdominal approach is recommended, while for tumors located below this line, a perineal or a retrorectal approach 1 Unit of Gastrointestinal Surgery, Service of Surgery, is advised [2] (Fig. 1). Both approaches are highly invasive Hospital de Sant Pau, Autonomous University of Barcelona, and the deep location of this lesion in the pelvis requires a Barcelona, Spain wide dissection. Advances in the laparoscopic approach to 2 Institute for Biomedical Research, Hospital de Sant Pau (IIB rectal cancer and total mesorectal excision have facilitated Sant Pau), Barcelona, Spain 13 Vol:.(1234567890) Surgical Endoscopy (2023) 37:9080–9088 9081 below the coccyx). In case of recurrence, a TEM approach was considered. We recorded the duration of the surgical procedure, length of hospital stay, and immediate morbidity (Clavien–Dindo classification). Following histopathological analysis of the surgical specimen, in cases of malignant findings, an oncological evaluation was made to determine whether further treatment was required. All patients had an annual follow-up and MRI or CT scan. This study did not require Institutional Review Board (IRB) approval. Surgical techniques All patients were preoperatively evaluated by means of colo- noscopy, CT scan, and/or MRI (Fig. 2). No patients had a preoperative biopsy of the lesion as part of the diagnosis. In the day before surgery, mechanical bowel preparation was performed. Surgery was performed under general anesthesia and endovenous antibiotic prophylaxis was provided. Fig. 1  Classical thumb rule for surgical excision of the RRT based on the location above or below S3 sacral vertebra. Sagittal cross MRI of Transabdominal approach a RRT​ The patient was placed in a standard position for the lower pelvis laparoscopic approach, with legs on stirrups and with knowledge of the anatomic features of the lower pelvis and shoulders supported for the Trendelenburg position. Four its minimally invasive surgery (MIS). MIS access does not trocars were used in all cases: a 10-mm trocar at the umbili- only dramatically reduce the invasiveness of the surgical cus, two 5-mm trocars on the right side of the lower abdo- approach but also breaks the old paradigm regarding the men, and one trocar on the left side (Fig. 3) [4]. Dissection location of the tumor in relation to the S3 vertebrae [1–3]. began at the right pararectal gutter and the mesorectal space Lower tumors are also accessible via the transabdominal was located. The mesorectal space was opened and explored route, thereby avoiding aggressive perineal or retrorectal up to the upper pole of the RRT. Blunt and sharp dissec- incisions for access in many cases. However, due to the tions were performed until the tumor was completely dis- infrequent incidence of RRT, MIS experience regarding sected. When approaching the most distal part of the RRT, treatment for this disorder treatment is scarce. The aim of especially in cases located juxta the anorectal sphincter, a this study was to evaluate the potential advantages of the simultaneous digital rectum control was particularly useful MIS approach in a prospective series of patients who under- to locate the specimen in order to rule out or reduce the went surgical resection of RRT. potential risk of rectal wall injury. The tumor was extracted inside a bag and a Blake drain with low pressure was placed [4]. Materials and methods Data regarding RRT at the Surgical Gastrointestinal Unit at Perineal approach Hospital de Sant Pau have been prospectively recorded since 1998 and were reviewed in April 2023. These data included The patient was placed in a prone position, with the legs all patients presenting with RRTs, defined as solitary lesions separated and the buttocks retracted. A vertical or transverse located extraperitoneally in the retrorectal space below the infra-coccygeal incision was performed, and the tumor was sacrum promontorium and not originating from digestive, excised. Primary closure of the skin was performed. urinary, or gynecological structures. We recorded patients’ age and sex, clinical symptoms, method of diagnosis, Transanal endoscopic microsurgery (TEM) surgical details, and short- and long-term outcome. Cases in whom imaging techniques showed malignant diagnosis In the case of recurrent RRT, we used the standard TEM were excluded. A laparoscopic approach was offered in all technique and the rectal mucosa was opened. Wide cases unless the tumor was located in a position and of a size dissection of the recurrent cyst was performed, followed by that facilitated easy access with a perineal approach (juxta or closure of the rectal wall by means of a v-lock suture. 13 9082 Surgical Endoscopy (2023) 37:9080–9088 Fig. 2  Preoperative abdomino-pelvic imaging test of a RRT: a cross sectional CT-scan; b 3D reconstruction of CT-scan Fig. 3  Image of a RRT excision with a transabdominal approach. Standard laparoscopy port positions are used 13 Surgical Endoscopy (2023) 37:9080–9088 9083 Results min in patients treated by the laparoscopic approach and 45 min in patients treated by the perineal approach. The During the study period, 23 patients diagnosed as having average postoperative hospital stay for all study patients RRT and eligible for non-extended surgery were evaluated was 4 days. Postoperative morbidity was low. There were for MIS excision. three cases of local infection (deep infection in two and There were 17 women and 6 men, with a median age wound infection in one). These infections were treated of 58 years (range 27–86 years). Twenty-two of the 23 with antibiotics and no aggressive measures were needed patients in the series underwent surgery. A closed follow-up (Clavien–Dindo I) (Table 3). was decided in the case of an older patient with a small The definitive histological diagnosis is summarized lesion. One of the 22 patients who underwent surgery was in Table 3. Two cases were malignant (mucinous reoperated for recurrent RRT via TEM. Sixteen patients adenocarcinomas). One of these two cases received (72%) underwent a transabdominal MIS. One of these adjuvant therapy (chemotherapy and radiotherapy) patients presented a very low recurrent tumor and was without recurrence 5 years later and the other patient treated with a TEM. Six patients (27%) with small (< 3 developed ovarian metastasis that required bilateral cm) and ultra-low juxta coccygeal lesions were approached salpingo-oophorectomy. At long-term follow-up (60 ± 12 through an open perineal route. months), one patient who was previously treated with Table 1 summarizes the clinical features, lesion size, an MIS approach and transperineal resection developed diagnostic methods, and preoperative clinical diagnosis. symptomatic recurrence and TEM excision was performed. The immediate outcome after surgery is summarized in There was no reported follow-up mortality in our study. Table 2. In the MIS group, there were no conversions or Table 4 compares the main variables analyzed in our intraoperative incidents other than accidental rupture of study between the two groups of patients treated with the cyst wall in four cases. Mean operating time was 158 RRTs, the laparoscopic/combined approach versus the perineal approach. Table 1  Description of cases: Case Sex Age (years) Clinical feature Diagnosis Size (mm) demography, clinical features and diagnosis 1 Male 64 Low abdominal pain CT scan + MRI 57 × 52 × 51 2 Female 73 Low abdominal pain MRI 40 × 15 3 Female 75 Casual diagnosis CT scan + MRI 55 × 60 × 35 4 Female 72 Low abdominal pain CT scan + MRI 26 × 22 × 15 5 Female 41 Low abdominal pain CT scan + MRI 47 × 49 6 Female 75 Casual diagnosis CT scan + MRI 79 × 36 × 25 7 Female 27 Low abdominal pain CT scan + MRI 25 × 30 × 30 8 Male 55 Low abdominal pain CT scan + MRI 23 × 20 × 30 9 Female 48 Casual diagnosis CT scan + MRI 38 × 40 × 60 10 Female 33 Casual diagnosis MRI 75 × 5 × 44 11 Female 59 Sciatic and lumbar pain CT scan 60 × 50 × 30 12 Female 38 Casual diagnosis CT scan 110 × 55 × 35 13 Male 84 Low abdominal pain CT scan 70 × 60 × 40 14 Female 86 Low abdominal pain CT scan 70 × 70 × 36 15 Male 63 Sciatic and lumbar pain MRI 50 × 60 × 40 16 Male 40 Low abdominal pain MRI 50 × 42 × 110 17 Female 32 Perianal abscess CT scan 70 × 40 × 20 18 Female 43 Casual diagnosis CT scan 35 × 25 × 40 19 Male 69 Casual diagnosis MRI 45 × 68 × 30 20 Female 76 Low abdominal pain MRI 30 × 16 × 20 21 Female 71 Casual diagnosis CT scan 37 × 26 × 29 22 Female 58 Low abdominal pain CT scan + MRI 25 × 20 × 20 23 Female 61 Casual diagnosis CT scan + MRI 48 × 20 × 24 13 9084 Surgical Endoscopy (2023) 37:9080–9088 Table 2  Surgery approach, Case Approach Operating time Surgical complications operating time and surgical (min) complications 1 Laparoscopy 140 Accidental tumor rupture 2 Perineal 60 No 3 Laparoscopy 240 Accidental tumor rupture 4 Follow-up observation 5 Laparoscopy 90 No 6 Laparoscopy + posterior transperineal (gluteal) 180 Accidental tumor rupture 7 Perineal 30 No 8 Perineal 30 No 9 Laparoscopy 180 No 10 Laparoscopy 90 No 11 Laparoscopy 75 No 12 Laparoscopy 145 No 13 Laparoscopy 180 No 14 Laparoscopy 190 No 15 Laparoscopy 200 No 16 Laparoscopy + posterior transperineal (sacro) 250 No 17 Laparoscopy + posterior transperineal 190 No 18 Laparoscopy 120 No 19 Laparoscopy 145 No 20 Perineal 60 No 21 Perineal 45 No 22 Perineal 50 Accidental tumor rupture 23 Laparoscopy 120 No Discussion with these experiences, we can see that our series pre- sents a higher number of patients operated by laparoscopy In our series of patients with RRT, the laparoscopic approach (72%, n = 16/22). Two of the most recent studies show the was performed in 16 patients (72%, n = 16/22). The remain- majority of patients underwent a perineal approach using ing 6 patients (27%) were treated by the perineal approach transsacrococcygeal or transperineal technique because the because they presented with small and distal tumors that tumors were located below the S3 sacral vertebra [1, 2]. were easily accessible by this route. Conversion to open Aubert et al. published the largest multicenter study surgery was not required in the minimally invasive surgery to date on the management of RRTs [6]. A total of 270 (MIS) group as there were no serious intraoperative compli- patients operated for RRT in 18 academic French centers cations. The patients clearly benefitted from the advantages were retrospectively included from 2000 to 2019. Of of the MIS approach. The average postoperative length of these, 27% (n = 72) underwent the laparoscopic anterior the hospital stay was short (4 days) and there was a low inci- approach, 70% (n = 190) the posterior approach, and 3% dence of postoperative morbidity (18%) (Table 4). (n = 8) a combined approach. Laparoscopy was frequently Two patients initially diagnosed with tail gut cysts were performed for RRTs that were symptomatic, large, or found to have mucinous adenocarcinoma after surgery in located above S3 vertebra. The authors concluded that spite of no signs of malignancy were present at preoperative these features may explain the poorer intraoperative results imaging. and the higher conversion rate and longer operative time. The rarity of RRTs makes it difficult to have large series They did not report any significant difference between of patients and long-term follow-ups. Currently, there are the two surgical approaches in terms of morbidity, a lack of quality information and experience regarding the reintervention, readmission, or recurrence. The results of management of this pathology, making it difficult to compare the study by Aubert et al. [6] are comparable to our study our results with other studies. results regarding the period in which it was carried out, Table 5 shows the results of studies published in the and it is indicative of how the laparoscopic approach is not last 5 years with more than 20 patients treated for retro- the most commonly used approach today for the treatment rectal tumors [1–3, 5, 6]. If we compare our study results of these tumors. 13 Surgical Endoscopy (2023) 37:9080–9088 9085 Table 3  Tumor characteristics, postoperative complications, hospitalization and recurrence Case Histology Postoperative complications Hospitalization Recurrence (days) 1 Hamartomatous cyst (tail gut) No 5 No 2 Hamartomatous cyst (tail gut) No 4 No 3 Mucinous adenocarcinoma No 7 Yes (reintervention: bilateral oophorectomy because of metastasis) 4 Follow-up observation 5 Schwanoma No 2 No 6 Mucinous adenocarcinoma No 8 No 7 Desmoid cyst No 1 No 8 Desmoid cyst No 1 No 9 Heterotipia salivary glands No 3 Yes (radiological estability) 10 Solitary fibrous tumor No 4 No 11 Neurofibroma Abscess 5 No 12 Teratoma No 8 No 13 Teratoma No 3 No 14 Hamartomatous cyst (tail gut) No 4 No 15 Schwanoma Abscess 14 No 16 Hamartomatous cyst (tail gut) Wound infection 4 No 17 Hamartomatous cyst (tail gut) No 3 Yes (reintervention: TEM) 18 Heterotipia salivary glands No 4 No 19 Glomus tumor No 3 No 20 Hamartomatous cyst (tail gut) No 4 No 21 Hamartomatous cyst (tail gut) No 3 No 22 Hamartomatous cyst (tail gut) Abscess 3 No 23 Hamartomatous cyst (tail gut) No 4 No Table 4  Variable comparison Laparoscopy approach or Perineal approach between patients with RRTs combined approach operated by laparoscopic or combined approach and patients Median age (years) 59.93 ± 17.41 60 ± 16.65 operated by perineal approach Median size (mm) 49.14 ± 9.73 25.74 ± 3.33 Median operating time (min) 158.43 ± 50.08 45.83 ± 12.38 Incidence of surgical complications 3/16 (18%) 1/6 (16%) Pathological diagnosis (%) Hamartomatous cyst (tail Hamartomatous gut): 31.25% cyst (tail gut): Mucinous adenocarcinoma: 66.66% 12.5% Mucinous Others: 56.25% adenocarcinoma: 0 Others: 33.33% Incidence of postoperative complications 3/16 (18%) 1/6 (16%) Incidence of recurrence 3/16 (18%) 0 Median hospitalization stay (days) 5 ± 2.88 2.6 ± 1.24 Additional surgical approaches are currently available provide safe tumor excision and a short operative time, low and feasible for this type of tumors, such as minimally inva- morbidity, and better postoperative recovery. The TEM sive transanal surgery/transanal endoscopic microsurgery approach was first described by Zoller et al. in 2007 [7], and (TAMIS/TEM) and robot. TAMIS or TEM are alternative studies with short series of patients suggest that despite its approaches for surgical treatment of RRTs. Both methods technical demands, the results are attractive, especially for 13 9086 13 Table 5  Literature review about surgical treatment of RRT (published in the last 5 years) Type of study Period of N total Sex Median Clinical features Approach Median Clavien AP malignancy Recurrence Median study age (years) size (cm) Dindo (n) follow-up classification (months) Ahmad Sakr Retrospective 2007–2018 24 Females: 51.5 Symptomatic: Anterior 5.5 ± 2.7 CD II: 9 2: 0 12 et al. [5] 18 10 laparoscopic: (37.5%) 1 neuroendocrine Males: 6 Asymptomatic: 10 CD III: 1 1 adenocarcinoma 14 Posterior: 11 (4.2%) Combined: 3 Orçun Yalav Retrospective 2009–2019 20 Female: 12 48.3 ± 14.2 Symptomatic: Anterior 5.4 ± 2.6 CD I: 25% 3: 1 53.8 ± 40 et al. [3] Male: 8 20 laparoscopic: CD II: 5% 2 chordoma 2 CD III: 5% 1 leiomyosarcoma Posterior: 14 Combined: 4 Carpelan Retrospective 2012–2017 52 Female: 40 43 Symptomatic: Anterior Max. tumor CD I: 11 4: 14 39 Holmström Male: 12 22 laparoscopic: length: 1 malignant tailgut et al. [2] Asymptomatic: 7 30 cyst 30 Posterior: 44 1 angiomyxoma Combined: 1 1 leiomiosarcoma 1 GIST Zeyu Li et al. Retrospective 2009–2019 44 Female: 33 50 Symptomatic: Anterior 5.6 CD I: 5 18: 9: 25 [1] Male: 11 44 laparoscopic: CD IIIa:1 5 originated in benign 3 CD Id: 1 presacral space tumors: 4 Posterior: 26 6 chordomas malignant Combined: 2 2 teratomas tumors: 5 5 metastasic adenocarcinoma Mathilde Retrospective 2000–2019 270 Female: 46 ± 15 Symptomatic: Anterior 5.7 ± 2.9 CD I–II: 56 22 20 27 ± 39 Aubert 213 151 laparoscopic: CD III–IV: benign et al. [6] Male: 57 Asymptomatic: 53 16 tumors: 119 Abdominal 15 open: 17 malignant Abdominal tumors: 5 robotic: 2 Posterior: 190 Combined: 8 Surgical Endoscopy (2023) 37:9080–9088 Surgical Endoscopy (2023) 37:9080–9088 9087 the deep pelvis and cystic lesions with benign appearance, suspected cases of malignancy without neighboring structure due to low intraoperative and postoperative complications invasion, provided care is taken for complete tumor resection [8–11]. In our study, a case initially operated with laparo- to avoid rupture of the wall of the tumor. This approach can scopic surgery had a distal recurrence and a rescue TEM avoid the more aggressive open alternative approaches. was performed. A systematic review by Mullaney et al. [12] included 82 patients, with 73 patients undergoing laparo- scopic or combined laparoscopic and perineal approaches and 9 patients received robot-assisted surgery. The review Conclusion found that robotically operated patients had longer opera- tive times but postoperative outcomes similar to those for RRT are rare tumors that grow in the retrorectal space. laparoscopic surgery patients [12]. Other smaller studies Surgical resection is indicated due to the potential risk of have reported shorter operative times, less blood loss, and malignancy. Surgery has classically been performed by the shorter hospital stays in patients who underwent robotic sur- posterior approach. However, with the new laparoscopic gery [13]. Despite not having any robot-operated patients techniques, MIS provides a safe and feasible alternative for in our study, our opinion is, the robot can be considered a resection of this type of tumors. good surgical approach for tumors located in the deep pelvis Funding Open Access Funding provided by Universitat Autonoma de because it allows better vision and aids manipulation of the Barcelona. deep pelvis structures. An important issue in the management of RRTs is the Declarations risk of malignant changes. This risk is variable and depends Disclosures Clara Galán, M. Pilar Hernández, M. Carmen Martínez, on of the type of the tumor. Several studies have reported Anna Sánchez, and Jesús Bollo y Eduardo Mª Targarona have no con- varying incidences of malignancy, with Sakr et al. [5] and flicts of interest or financial ties to disclose. Mathis et al. [14] reporting incidences up to 8% and 13%, respectively. A recent systematic review by Nicoll et al. [11] Open Access This article is licensed under a Creative Commons Attri- in 2019 found an overall rate of neoplastic transformation bution 4.0 International License, which permits use, sharing, adapta- of 26% in tail gut cysts. Another systematic review in 2020, tion, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, by Feng Liang et al. [15], reported that up to 30% of tail gut provide a link to the Creative Commons licence, and indicate if changes cysts in the literature were malignant in the literature. were made. The images or other third party material in this article are Long-term follow-up of retrorectal tumors (RRTs) is included in the article’s Creative Commons licence, unless indicated mandatory due to the possibility of recurrence. Recurrence otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not rates are generally lower for benign tumors (1–2%) than permitted by statutory regulation or exceeds the permitted use, you will for malignant tumors (30–50%) [2]. In our study, three need to obtain permission directly from the copyright holder. To view a patients presented recurrence, two with a benign RRT and copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. one with a malignant RRT. Two of these patients underwent re-operation. The third patient was radiologically stable and close follow-up was decided. The main limitation of our study is that due to the rarity References of the RRTs, the number of cases is limited. Further research 1. Zeyu L, Min L (2021) Presacral tumor: insights from a decade’s with a multicenter prospective design could help determine experience of this rare and diverse disease. 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