Deep pelvic endometriosis: clinical features, diagnosis, and treatment - a comprehensive review

Endometriosis is associated with an increased risk of adverse pregnancy outcomes, including miscarriage, intrauterine growth restriction, hypertensive disorders, antepartum hemorrhage, and cesarean delivery. Women with posterior DIE who have not undergone complete excision appear particularly vulnerable to complications during pregnancy and delivery. Population studies indicate higher rates of preterm birth, placenta previa, placental abruption, hypertensive disorders, and cesarean delivery in women with endometriosis compared with unaffected women [ 106 ]. The pathogenic mechanisms underlying these complications may be related to chronic inflammation, adhesions, and the invasion of decidualized ectopic endometrium into the vessel walls. The incidence of placenta previa is significantly higher in women with posterior DIE compared to the general population [ 106 ]. The abnormal implantation of the blastocyst due to uterine dysperistalsis may contribute to the increased risk of placenta previa in these women. Complete surgical excision of DIE before pregnancy has been suggested to improve conception rates and reduce postpartum problems. However, women undergoing prior DIE surgery may still be at a higher risk of placenta previa, gestational hypertension, and intrauterine growth restriction [ 107 ]. Previous DIE surgery does not appear to increase the risk of failed vaginal delivery [ 108 ]. “Completeness of surgery” in endometriosis refers to eradicating all endometrial/endometriotic cells. However, it is challenging to achieve complete excision, and there is an ongoing debate about the necessity of complete excision in cases of profound endometriosis. The fibrotic layer surrounding deep endometriosis and the presence of asymptomatic nodules without signs of progression further complicate the decision-making process.

Gynecologists are central to diagnosis and hormonal management, yet colorectal surgeons are essential when rectal or sigmoid invasion is suspected. Urologists may be involved in cases with bladder or ureteral involvement, particularly when imaging reveals hydronephrosis or impaired ureteral peristalsis. Additionally, pain specialists play a critical role in managing neuropathic pain and guiding conservative therapies. Fertility experts contribute to strategic planning for patients with reproductive goals, particularly when assisted reproductive technology (ART) is considered. Multidisciplinary team meetings prior to surgery allow for coordinated decision-making, appropriate referral, and individualized surgical planning [ 36 ]. These integrated care models improve not only surgical outcomes but also patient satisfaction and long-term quality of life [ 37 ].

Disc excision involves full-thickness rectovaginal DIE excision using a combination of laparoscopic and transanal techniques. The nodule is separated from the rectal wall and excised when necessary. This procedure requires the complete removal of the diseased intestinal wall segment, followed by stapling or suturing of the resulting defect. Disc excision is suitable for lesions that affect a small portion of the intestinal wall. It has shown promising results and fewer postoperative difficulties compared to segmental resection. However, it carries a higher risk of complications, including rectovaginal fistulas [ 66 ]. Most authors recommend removing lesions greater than 30 mm in diameter as segmental resections, in order to prevent deformation of the intestinal axis and subsequent stricture. However, a study found that over 13% of patients with lesions larger than 30 mm underwent discoid excision, suggesting that this approach remains controversial and warrants further investigation [ 67 ]. According to the FRIENDS survey, the rate of the rectovaginal fistula was 3.6% in individuals who underwent disc excision, which was three times higher than the rate in those who underwent shaving excision (1.3%) and similar to segmental resection (3.9%) [ 61 ]. Rectovaginal fistulas were more frequent (11.9%) in a specific group of women with rectal nodules located approximately 5.5 cm above the anus. These nodules had a mean diameter greater than 3 cm in 93% of cases and were associated with adjacent vaginal involvement in 83.3% of cases, with a diameter greater than 3 cm in 69% of cases [ 68 ]. In a group of individuals treated for low rectal nodules, there was a higher prevalence of bladder impairment, reaching up to 9%. The literature reports low recurrence rates, with a second-year risk of recurrence being 1.8% [ 43 ].

Leuprolide acetate, a GnRH agonist, can be combined with add-back norethindrone medication for symptom management in women with rectovaginal endometriosis. Leuprolide may also be administered preoperatively to reduce disease severity. Elagolix, an oral GnRH antagonist, has shown significant efficacy compared with placebo in treating dysmenorrhea and non-menstrual discomfort associated with endometriosis. However, it may cause a dose-dependent decrease in bone mineral density [ 48 , 49 ]. Available preparations include non-peptide oral forms such as elagolix, relugolix, linzagolix, ozarelix, and abarelix, and injectables such as cetrorelix and ganirelix [ 50 ].

Oral contraceptives are often the first-line medical treatment due to their effectiveness, minimal side effects, and affordability. Monophasic estrogen-progestin combinations, such as ethinyl estradiol 0.01 mg plus cyproterone acetate 3 mg or norethindrone acetate 2.5 mg/day administered continuously for 12 months, have shown a significant reduction in pain, including deep dyspareunia and dyschezia [ 45 ]. Both medications significantly reduced pain symptoms, including deep dyspareunia and dyschezia. There were no statistically significant between-group differences in treatment satisfaction or pain alleviation [ 14 ].

Danazol, administered at 200 mg/day for 12 months, has been used to treat women with rectovaginal endometriosis. It has been shown to reduce symptoms such as dysmenorrhea, dyspareunia, dyschezia, and pelvic discomfort. In addition, a reduction in the volume of rectovaginal plaques has been reported during treatment [ 51 ].

The progression of deep infiltrating endometriosis, especially involving the bowel, varies significantly across patients. Studies have documented scenarios of both stability and progression, with hormonal suppression often associated with symptomatic improvement and lesion quiescence, particularly in non-obstructive lesions [ 52 ]. However, progressive fibrosis, increasing lesion size, or symptomatic bowel stenosis (>50%) are indicators for timely surgical intervention [ 53 ]. A comprehensive assessment combining imaging, symptom burden, and quality of life metrics is essential for stratifying patients into expectant, medical, or surgical pathways. Surgical decision-making should not solely rely on anatomical findings but also incorporate data on disease behavior and patient-centered goals [ 53 , 54 ].

In patients with bowel stenosis of less than 60%, hormonal suppression has been shown to reduce pain and gastrointestinal symptoms significantly. It is highly beneficial in preventing recurrence, and after surgery, women who do not wish to conceive immediately may be prescribed hormone suppression to reduce the risk of recurrence [ 44 ].

Shaving excision involves ablating invasive, fibrotic endometriotic implants without entering the intestinal lumen. The goal is to remove the endometriotic and fibrotic lesions from the colon while preserving the bowel mucosa and a small amount of the muscularis. The procedure is performed layer by layer until healthy underlying tissue is reached. The shaving approach includes separating the anterior rectum from the posterior vagina, excising or ablating the DIE nodule from the posterior part of the cervix, resecting the posterior vaginal fornix, and closing the vagina [ 58 ]. Complications such as bowel perforation and rectovaginal fistulas can occur but are relatively rare. Shaving excision has shown promising results regarding symptom improvement and low recurrence rates. The main steps of the shaving approach entail lateral ureter detection far from the actual lesion. 10% of nodules larger than 3 cm involve the ureter, necessitating ureterolysis with or without prior ureteral stenting [ 43 ]. Three steps have been described: -Separation of the anterior rectum from the posterior vagina, -Excision or ablation of the DIE nodule from the posterior part of the cervix, and -Resection of the posterior vaginal fornix and vaginal closure [ 43 ]. -Separation of the anterior rectum from the posterior vagina, -Excision or ablation of the DIE nodule from the posterior part of the cervix, and -Resection of the posterior vaginal fornix and vaginal closure [ 43 ]. In retrospective research, the shaving technique was used in 3298 patients with DIE; the complication rate was modest, with only one rectal perforation, three cases of ureteral injury, and one case of fecal peritonitis [ 58 ]. Roman et al. and Koninckx et al. described 1.7% and 2.2% of late bowel perforation requiring colostomy, respectively [ 59 , 60 ]. Rectovaginal fistulas were detected in 0.24% of the patients, while Roman et al. reported 0.6% in a sample of 546 cases [ 61 ]. After shave excision, patients demonstrated favorable outcomes, with only 4% of patients experiencing symptom recurrence [ 62 ]. Patients who intended to become pregnant had a pregnancy rate of 65.4%, with 59% of those women conceiving naturally. Any bleeding during surgery was 1.6%, and 0.09% of cases were reported [ 63 , 64 ]. The overall rate of prolonged catheterization was 0.19%. Nonetheless, it is crucial to emphasize that catheterization was necessary for no more than six weeks and that bladder atony was not permanent [ 60 ]. Research by Roman et al. showed that shaving had better functional results than bowel resection for postoperative constipation and anal continence [ 59 ]. About 10% of patients who had shave excition experienced a return of pain [ 65 ]. During a 3-year follow-up, Roman et al. observed a 4% recurrence rate and an 8.7% recurrence rate after a 5-year follow-up. In this study, only 2.4% of patients needed reintervention [ 59 ]. Videos on surgical technique are shown in Online Resource 1 and Online Resource 2.

Surgery is considered the primary treatment for intestinal endometriosis due to high recurrence rates following the discontinuation of medical management. Approximately one out of every three women who receive hormonal treatments fail and requires surgery. In cases where women desire to get pregnant, in vitro fertilization (IVF) should be considered, and surgery is advised when IVF attempts fail repeatedly [ 55 , 56 ]. Different surgical treatment options for deep infiltrating endometriosis (DIE) include shaving, disc excision, and colorectal segmental resection. The choice of surgical procedure depends on the anatomical extent of disease and the patient's symptoms [ 57 ].

Ureteral endometriosis is typically managed with ureterolysis, whereas bladder endometriosis is usually treated with segmental bladder resection. In cases of hydroureteronephrosis caused by intrinsic involvement, ureteral resection may be required. Surgical approaches such as ureterolysis, ureteral anastomosis, and ureteroneocystostomy, however, may result in complications including ureteral or utero-vaginal fistulas, as well as persistent or recurrent stenosis [ 92 ].

Deep infiltrating endometriosis frequently involves extra-intestinal sites such as the uterosacral ligaments, posterior vaginal fornix, parametrium, and pelvic nerve plexuses. Surgical excision in these regions aims to restore organ function and relieve neuropathic pain. Uterosacral ligament excision is commonly performed in cases of retrocervical nodules and may provide significant pain relief. Vaginal wall involvement often requires partial posterior colpectomy, particularly when associated with large rectovaginal nodules. Lesions infiltrating the parametrium or sacral nerve plexus (S2–S4) pose considerable surgical challenges. In such cases, nerve-sparing techniques are essential to prevent long-term bladder, rectal, or sexual dysfunction. Laparoscopic and robot-assisted nerve-sparing approaches enhance visualization and precision, thereby reducing postoperative morbidity [ 90 ]. Surgical decision-making must balance radical excision to prevent recurrence with organ and nerve preservation to maintain quality of life. Lesions larger than 3 cm, symptomatic parametrial infiltration, and documented neuropathic pain are potential indications for extensive resection [ 91 ]. Conversely, asymptomatic lesions in high-risk zones may be approached conservatively. The evolving philosophy of “functional radicalism” advocates tailored excision based on both anatomical extent and symptomatology.

Aromatase inhibitors have shown limited efficacy when used as monotherapy, without concomitant ovulation-inhibiting agents [ 14 ]. It is important to note that the choice of medical treatment should be individualized based on the patient's specific needs and preferences, and a multidisciplinary approach involving gynecologists, pain specialists, and fertility experts may be necessary to provide comprehensive care for patients with DIE.

Certified endometriosis centers are increasingly recognized as crucial institutions for the comprehensive and standardized management of DIE. The GDG specifically recommends that women with deep endometriosis be referred to a center of expertise [ 20 ]. These centers offer a structured framework that includes specialized training, high-volume surgical teams, and evidence-based protocols, all of which contribute to improved patient outcomes. Accreditation systems, such as those endorsed by the European Endometriosis League (EEL) and national health authorities, set minimum criteria for surgical expertise, multidisciplinary coordination, access to advanced imaging, and postoperative follow-up [ 38 ]. Studies have shown that treatment in certified centers correlates with higher surgical success rates, lower complication rates, and more efficient symptom control [ 39 ]. Moreover, these centers are well-positioned to deliver long-term, individualized care pathways, addressing fertility preservation, chronic pain, and quality of life. By consolidating resources and expertise under a unified system, certified centers represent the gold standard for DIE management in modern gynecologic practice [ 40 ].

Clinical history and examination are insufficient for diagnosing DIE [ 19 ]. According to the 2022 ESHRE guideline, certain presentations of endometriosis—such as ovarian endometrioma and deep endometriosis—can be diagnosed using transvaginal ultrasound (TVUS) or MRI, without requiring laparoscopy and histological confirmation. Laparoscopy may still be considered in cases of negative imaging or when empirical treatment proves unsuccessful [ 20 ]. Accurate preoperative planning using diagnostic imaging is essential before surgery for DIE. Transvaginal ultrasound (TVUS) can be used to verify clinical suspicion of deep endometriosis in the rectal or rectosigmoid region [ 21 ]. The American Institute of Ultrasound in Medicine (AIUM) and the International Deep Endometriosis Analysis (IDEA) groups have described diagnostic techniques, including the ‘sliding organ’ maneuver, tenderness-guided transvaginal sonography, and rectal-water transvaginal sonography. The “slide sign” on TVUS can predict Pouch of Douglas (POD) obliteration in endometriosis [ 22 ]. Recent research has shown that the ‘sliding sign’ demonstrates high accuracy, sensitivity, and specificity for predicting POD obliteration [ 23 ]. On TVUS, deep infiltrating endometriosis appears as hypoechoic nodular or infiltrating areas in the pelvis, particularly in the posterior compartment, uterosacral ligaments, rectovaginal septum, rectosigmoid, or bladder. In some cases, internal hyperechoic foci or complex internal cysts may be present in infiltrative regions of DIE [ 24 ]. TVUS has shown excellent diagnostic accuracy, with up to 91% sensitivity and 98% specificity in detecting posterior compartment and bowel endometriosis [ 21 ]. It can also predict invasion of the submucosal/mucosal layer with reasonable accuracy [ 25 ]. MRI is the second imaging test, after TVUS, to confirm the presence of endometriosis. The optimal timing of MRI in the menstrual cycle remains debated, with some authors recommending it during menstruation and others just before. MRI is not recommended before 8 th day of the menstrual cycle due to the spontaneous T1 hyperintensity of blood [ 26 ]. Expanding the vaginal and rectal cavities with ultrasound gel or water can improve the differentiation of components surrounding the posterior cul-de-sac on MRI. MRI with vaginal and rectal gel has shown high sensitivity and specificity in identifying posterior cul-de-sac obliteration (sensitivity and specificity of 99% and 96%, respectively) [ 27 ]. The diagnosis of rectosigmoid endometriosis can be made using MRI, rectal endoscopic sonography (RES), and 3D-recto sonography (3D-RSG), with no significant difference in diagnostic accuracy between the three methods [ 28 ]. Current consensus highlights the high diagnostic value of TVUS and MRI in detecting DIE, particularly in experienced hands. Beyond these established modalities, newer techniques—such as ultrasound elastography, diffusion-weighted MRI, and contrast-enhanced MRI—are being evaluated for their ability to differentiate fibrotic from active lesions and improve detection of subtle implants [ 26 , 29 ]. In parallel, research into non-invasive biomarkers, including microRNAs, CA-125 variants, and endometrial nerve fiber density, has shown promise but still requires validation before routine clinical use [ 30 , 31 ]. As the diagnostic landscape evolves, combining imaging with biomarker panels may pave the way toward earlier and more personalized detection strategies for DIE. The classification of deep infiltrating endometriosis (DIE) remains a challenging yet essential aspect of clinical management. Several classification systems have been proposed to improve diagnostic standardization, surgical planning, and communication among multidisciplinary teams.

Treatment for DIE can be complex and should be tailored to the individual patient's symptoms, desire for fertility, and comorbidities. Medical treatment options include combined oral contraceptives, progestogens, and gonadotropin-releasing hormone (GnRH) analogs or antagonists. Medical treatment aims to induce hypoestrogenic conditions, promote atrophy or quiescence of endometriotic lesions, and decrease chronic peritoneal inflammation [ 41 ]. Systematic reviews have shown that between 5 and 59% of women still report pain at the end of medical treatment and only 11–19% experience no improvement—implying that the majority do benefit from symptom relief [ 42 ]. However, surgical treatment is typically considered the primary option for symptomatic DIE patients, especially those with bowel involvement. The main goal of surgery is to restore normal anatomy by removing endometriotic lesions [ 43 ]. According to the 2022 ESHRE guideline, clinicians may consider surgical removal of deep endometriosis, as it can reduce endometriosis-associated pain and improve quality of life. The Guideline Development Group (GDG) further recommends that patients undergoing surgery, particularly for deep endometriosis, be fully informed about the potential risks, expected benefits, and long-term impact on quality of life [ 20 ].

Colorectal segmental resection consists of excising the nodule along with surrounding structures, opening the pararectal spaces, and preserving the inferior hypogastric plexus. The rectum is then resected with a short margin of healthy tissue and anastomosed to the remaining bowel using stapling or suturing techniques. This procedure is generally reserved for large, obstructive, or multifocal lesions. Compared to shaving or disc excision, it carries a higher risk of complications, including anastomotic leakage, rectovaginal fistula, and postoperative voiding dysfunction. In some cases, a temporary diverting stoma may be required [ 69 ]. In a comparative study, discoid colorectal resection demonstrated advantages over segmental colorectal resection. Discoid resection had a shorter operating time (155 vs. 180 minutes, p =.03) and hospital stay (7 vs 8 days, p =.002). Additionally, discoid resection had a lower rate of postoperative voiding dysfunction (19% vs. 45%, p =.03) and voiding dysfunction lasting longer than 30 days, which required bladder self-catheterization (0 vs 22%, p = .005). These findings highlight the benefits of discoid resection, including comparable surgical complication rates when compared with segmental resection and advantages in terms of operating time, hospital stay, and voiding dysfunction [ 70 ]. Women with intestinal obstructions larger than 2–3 cm or greater than 50% are advised to undergo elective bowel resections [ 71 ]. However, this recommendation remains debated. It is important to note that achieving a tension-free, well-vascularized anastomosis becomes more challenging as the level of bowel resection decreases [ 43 ]. Low and ultra-low rectal resections, with a distance from the anal border of 6 or 4 cm, are associated with a higher risk of complications. A protective colostomy is required in approximately 10–14% of women undergoing bowel surgery for deep endometriotic lesions [ 72 ]. Patients were assigned to the radical surgery arm in the randomized experiment known as Functional Outcomes of Surgical Treatment of Deep Endometriosis Infiltrating the Rectum (ENDORE). Colorectal resection was performed in cases of small (<2.9 cm) and very small (<1 cm) rectal nodules, which represent less than 20% of the total cases in the series. This strategy was selected in patients with multiple colorectal nodules, including at least one rectal lesion, when the distance between consecutive nodules was too short to allow for multiple shavings or discoid excisions [ 73 ]. In an analysis of 1889 intestinal resections performed for deep endometriosis, the mean operating time ranged from 101 to 436 minutes, while the length of hospital stay varied from 4 to 14 days. Major complications occurred in approximately 11% of women overall, including anastomotic leakage (2.7%), fistula formation (1.8%), bowel obstruction (2.7%), and hemorrhage (2.5%) [ 3 ]. Segmental bowel resection has been reported to successfully alleviate dysmenorrhea, dyspareunia, and dyschezia in more than 90% of women at one-year follow-up. However, bowel resection for deep endometriosis carries a considerable risk of complications, with overall rates approaching 22% and serious events such as leakage, rectovaginal fistula, or severe obstruction occurring in about 11% of cases [ 57 ]. Across published series, rectovaginal fistula and anastomotic leakage remain significant problems associated with colorectal sutures, with reported rates ranging from 0% to 18.1%. The risk of these complications appears to correlate with the depth of rectal infiltration, being higher in cases of deeper bowel involvement [ 74 , 75 ] . Colorectal resection is associated with several significant side effects: -Rectal denervation: Mobilization and sectioning of the mesocolon during the procedure can lead to rectal denervation, affecting the normal functioning of the rectum. -Higher risk of stenosis: The frequency of stenosis in the colorectal anastomosis is reported to be higher in patients undergoing colorectal resection than in those treated for rectal cancer. -Altered bowel function: The procedure reduces the volume and compliance of the rectal reservoir, which can result in changes in stool consistency and frequency. These side effects should be considered when evaluating the potential risks and benefits of colorectal resection in treating bowel endometriosis [ 76 , 77 ]. -Rectal denervation: Mobilization and sectioning of the mesocolon during the procedure can lead to rectal denervation, affecting the normal functioning of the rectum. -Higher risk of stenosis: The frequency of stenosis in the colorectal anastomosis is reported to be higher in patients undergoing colorectal resection than in those treated for rectal cancer. -Altered bowel function: The procedure reduces the volume and compliance of the rectal reservoir, which can result in changes in stool consistency and frequency. These side effects should be considered when evaluating the potential risks and benefits of colorectal resection in treating bowel endometriosis [ 76 , 77 ]. Excessive intraluminal colonic pressure can affect the anal sphincter, weakening over time and resulting in urgency and fecal incontinence. A prospective review of 128 individuals who underwent segmental resection for bowel endometriosis reported sustained improvements in sexual and urinary function one year after surgery. However, anastomotic leaking occurred at a rate of 7.4% [ 78 ]. Several publications have reported a significant reduction in the bowel lumen at the site of colorectal anastomosis performed for endometriosis, mainly when transanal staplers are used. These results can be attributed to removing a portion of the digestive tract, bowel denervation, lack of compliance, or hypersensitivity. Consequently, patients may experience distressing issues such as anal incontinence, severe dyschezia, and fecal urgency. The improvement of functional problems over time may vary, highlighting the importance of long-term monitoring for their evaluation [ 43 , 79 ]. Sectioning the mesentery close to the intestinal wall, while preserving mesenteric and branching arteries, has been shown to reduce the risk of intestinal denervation and improve postoperative bowel function. Evidence from patients with sigmoid tumors and benign intestinal disease indicates that preserving the inferior mesenteric artery (IMA), its branches, and adjacent nerve fibers may reduce postoperative defecatory dysfunction following left hemicolectomy. More recently, a prospective cohort study introduced Mesenteric Vascular and Nerve-Sparing Surgery (MSS) in laparoscopic segmental bowel excision for deep infiltrating endometriosis. Among 62 patients, major complications requiring reoperation occurred in 4 cases (6.5%), with only one anastomotic leak (1.6%). Postoperatively, there were significant improvements in dysmenorrhea (p<.001; r = –0.86), dyspareunia (p<.001; r = –0.80), dyschezia (p<.001; r = –0.86), and dysuria (p<.001; r = –0.56). These findings suggest that MSS, particularly when combined with pelvic nerve-sparing techniques, is a reliable, safe, and effective approach to reduce functional morbidity following radical surgery for DIE requiring segmental intestinal resection [ 80 , 81 ]. Estimating rectal vascularization after intraoperative shaving is challenging, which complicates the prediction of postoperative fistula risk. Indocyanine green (ICG) fluorescence angiography has emerged as a valuable tool for intraoperative assessment of tissue perfusion. A recent meta-analysis including 555 patients demonstrated that ICG significantly reduced anastomotic leak rates in colorectal surgery. ICG can be applied not only after resection but also following deep shaving to evaluate rectal wall perfusion. In colorectal surgery, its intraoperative use has consistently been associated with improved perfusion assessment and a lower incidence of anastomotic leakage [ 82 , 83 ]. Based on the provided references, the rates of postoperative pain recurrence following bowel resection and disc excision are reported to be higher than shaving. Cicco et al. suggested that complication rates of segmental resections are high, but they may be slightly lower after resections for endometriosis compared to other indications [ 84 ]. Donnez & Roman indicate that postoperative pain recurrence may occur regardless of the surgical technique, including bowel resection [ 43 ]. Hence, the recurrence rate of discomfort following conservative surgery—such as full-thickness disc excision or rectal shaving—appears comparable to rates observed after more radical procedures, including bowel resection. Unlike segmental resection, these conservative techniques do not require mesorectal sectioning or extensive colon mobilization. Shaving, in particular, has been shown to effectively relieve digestive symptoms while preserving both sensory and motor intestinal function. Furthermore, the use of semicircular rectal sutures during disc excision, whether performed laparoscopically or with transanal staplers, may reduce the risk of postoperative digestive tract stenosis [ 68 ]. Moreover, compared with colorectal resection, conservative approaches such as disc excision or rectal shaving are associated with a smaller reduction in rectal length and rectal reservoir capacity. Studies evaluating surgical outcomes for rectovaginal DIE nodules have reported that anastomotic leakage, delayed hemorrhage, and long-term bladder catheterization are more frequently observed after bowel resection than after shaving or disc excision [ 85 , 86 ]. The results of extending the follow-up period for an additional five years (from 60 to 116 months) did not alter the overall outcomes [ 85 ]. Patients managed conservatively continued to face the risk of rectovaginal fistula, which is more strongly associated with the opening and resection of the bowel rather than the vagina, especially when treating lower lesions [ 58 ]. Experienced surgeons can manage more than 80%–90% of individuals with colorectal rectovaginal deep infiltrating endometriosis (DIE) [ 86 ]. The laparoscopic shaving method has been shown to preserve intestinal neuronal activity [ 87 ]. A retrospective comparison of digestive outcomes found that conservative approaches were associated with a lower risk of postoperative constipation and improved gastrointestinal quality of life [ 86 ]. It is not recommended to undergo intestinal resection with the expectation of alleviating functional bowel issues. Conservative treatments may reduce the incidence of constipation compared to colon resection, improve anal continence, improve gastrointestinal quality of life, and have no significantly higher risk of endometriosis recurrence in the digestive system [ 85 ] . Recurrent lesions are commonly observed after bowel resection and disc excision. In over 10% of cases, surgical margins still show residual disease, and some studies have reported positive margin rates as high as 22% [ 88 ]. Three main considerations support a conservative approach. First, colon resection may lead to challenging postoperative functional disorders. Second, occult microscopic endometriosis (OME) can persist, raising the possibility of incomplete excision. Third, opening the colon increases the risk of postoperative complications. Notably, OME has been identified at resection margins even after radical segmental procedures [ 88 ]. It remains uncertain whether residual endometriotic foci after rectal shaving, disc excision, or bowel resection may proliferate and contribute to postoperative recurrence. Current evidence provides limited data to precisely quantify the risk of rectovaginal DIE recurrence following these procedures [ 89 ].

DIE is a heterogeneous disease that demands individualized, multidisciplinary care. Diagnosis is best supported by high-quality imaging, while medical therapy alleviates symptoms for many patients; surgery is reserved for persistent, severe, or obstructive disease. Several surgical approaches exist—shaving, discoid excision, and segmental resection—and the choice should be tailored to lesion extent, symptom burden, and fertility goals, ideally in expert centers. Because functional morbidity rises with more radical procedures, the overarching aim is to relieve pain and restore function while preserving bowel, bladder, and reproductive health. The need for “complete” excision remains debated; in selected patients, stabilizing, asymptomatic nodules may be observed rather than removed to avoid overtreatment. Ultimately, management should be precise enough to reduce disease burden and protect quality of life, yet prudent enough to minimize complications and safeguard future fertility through shared decision-making.

Progestins, such as dienogest and norethindrone acetate (NETA), have been extensively studied for the management of endometriosis. Dienogest and NETA have shown comparable efficacy in reducing endometriosis-associated pain in women with rectovaginal disease. Side effects, including weight gain, spotting, and low libido, were reported in both groups, with dienogest demonstrating a more favorable tolerability profile [ 46 , 47 ].

Stablishing a direct link between colorectal endometriosis and infertility remains challenging. Evidence suggests that endometriosis reduces the likelihood of spontaneous conception, particularly in women with advanced disease. Surgical excision of endometriotic lesions has been associated with improved spontaneous pregnancy rates [ 98 ]. However, recent studies have reported no significant differences in pregnancy or live birth rates after IVF/ICSI among women without surgery, partial excision, or complete excision of endometriotic lesions. A systematic review and meta-analysis indicated that women undergoing surgery for deep infiltrating endometriosis prior to IVF achieved higher live birth and pregnancy rates compared with IVF alone [ 99 ]. These findings should be interpreted with caution, as results vary across studies and individual cases. Current expert opinion emphasizes a personalized approach: in women with extensive DIE, surgical excision may improve fertility and pain outcomes, but the potential benefits must always be weighed against surgical risks, particularly to ovarian reserve. In patients at risk of compromised ovarian reserve—such as those undergoing bilateral endometrioma surgery or extensive ovarian manipulation—fertility preservation becomes a crucial consideration. Ovarian tissue cryopreservation has emerged as a promising option, particularly in younger patients or those requiring radical surgery [ 100 ]. Furthermore, GnRH analog pretreatment may help reduce follicular loss prior to surgical excision, although its impact remains under investigation [ 101 ]. Other strategies, such as oocyte or embryo cryopreservation before extensive surgery, may be appropriate in women who desire future fertility, and their discussion should form part of individualized reproductive planning. The success of ART in women with endometriosis is influenced by disease severity, prior surgeries, and the extent of ovarian damage. Recent data suggest that while ART outcomes may be comparable to non-endometriosis populations in early-stage disease, advanced DIE with ovarian involvement poses significant challenges [ 102 ]. Tailoring fertility preservation strategies based on individual risk profiles and involving reproductive specialists in early decision-making is therefore essential. In addition to these considerations, the preservation of ovarian reserve is paramount, particularly in patients undergoing surgery for bilateral endometriomas or extensive DIE excision. Preoperative assessment using anti-Müllerian hormone (AMH) levels and the adoption of tissue-sparing techniques with minimal thermal damage are essential for optimizing fertility outcomes [ 103 ]. Moreover, individualized surgical planning, tailored to the patient’s reproductive goals, remains a cornerstone of management. The role of assisted reproductive technologies (ART) in DIE remains debated. While some studies advocate for surgical excision of endometriosis lesions prior to IVF, citing improved implantation and pregnancy rates, others suggest that surgery may offer no additional benefit compared to direct ART [ 104 ]. According to the 2022 ESHRE guideline, the decision to offer surgical excision of deep endometriosis lesions prior to ART should be guided mainly by pain symptoms and patient preference, as evidence on its effectiveness for reproductive outcomes remains limited due to a lack of randomized trials [ 20 ]. A recent meta-analysis indicated that patients who underwent DIE surgery prior to IVF had higher live birth and pregnancy rates, especially among those with advanced disease or previous failed ART attempts [ 105 ]. Thus, the timing and necessity of surgical intervention should be carefully evaluated on a case-by-case basis, weighing symptom relief, organ preservation, and reproductive success.

Endometriosis is a complex gynecologic disease that affects women of reproductive age and is associated with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. It is categorized into different phenotypes, including ovarian endometrioma, superficial peritoneal endometriosis, and deep infiltrating endometriosis (DIE) [ 1 ]. Over 20% of women with endometriosis are estimated to have DIE [ 2 ]. DIE is considered the most severe form of endometriosis and requires complex clinical management. Deep infiltrating endometriosis can involve the rectovaginal septum, utero-ovarian and uterosacral ligaments, and the muscular wall of pelvic organs. Bowel involvement is estimated to occur in 3.8% to 37% of cases, while urinary tract involvement is relatively low, ranging from 1% to 6% [ 3 , 4 ]. Urinary tract DIE, on the other hand, might be clinically “silent,” leading to ureteral obstruction and, ultimately, renal failure [ 5 ]. This article provides a comprehensive review of deep infiltrating endometriosis, focusing on its clinical features, diagnostic approaches, and current treatment strategies, including outcomes and special considerations.

The revised American Society for Reproductive Medicine (rASRM) classification is widely used but primarily assesses peritoneal and ovarian endometriosis, providing insufficient detail for DIE. In contrast, the Enzian classification was specifically developed for DIE and provides a topographic, depth-based anatomical mapping of lesions, particularly in the retroperitoneal space. It evaluates compartments A (vagina/rectovaginal septum), B (uterosacral ligaments), and C (rectum/sigmoid), with extensions for other organs (e.g., F for bladder) [ 32 ]. The VNESS (Visual Numeric Endometriosis Scoring System) combines lesion size and location into a single score, aiming to predict surgical complexity and postoperative outcomes [ 33 ]. Recently, the dPEI (deep Pelvic Endometriosis Index) has emerged as an MRI-based tool to assess lesion burden and predict surgical difficulty and postoperative complications. However, for fertility prognosis, the Endometriosis Fertility Index (EFI) remains the most validated scoring system [ 34 , 35 ]. While no single system captures all aspects of DIE, using a combination of anatomic (Enzian), radiologic (dPEI), and surgical (rASRM, VNESS) tools may offer a more comprehensive classification framework, supporting both preoperative planning and interdisciplinary collaboration. DIE often involves multiple pelvic compartments and adjacent organ systems, necessitating a multidisciplinary approach to ensure optimal outcomes. The complexity of symptoms—ranging from chronic pelvic pain and infertility to gastrointestinal and urological dysfunction—requires the combined expertise of various specialists.

The pathophysiology of DIE is defined by the infiltration of endometrial tissue into organs deeper than 5 mm, with the gastrointestinal tract being a common site of involvement [ 2 ]. DIE can lead to clinical complications, including increased circulating cell-derived microparticles and larger implant sizes [ 6 ]. The understanding of the pathophysiology of endometriosis, particularly DIE, is still evolving, and further research is needed to elucidate the underlying mechanisms and develop targeted therapeutic approaches. The pathogenesis of endometriosis involves alterations in hormonal function (estrogen and progesterone receptors) and immunological factors such as peritoneal macrophages, natural killer cells, and lymphocytes. These changes contribute to the aggressive behavior of DIE [ 7 ]. Studies have shown that women with endometriosis have reduced cytotoxic activity of natural killer cells in their peritoneal fluid and plasma [ 8 ]. The accumulation of iron and oxidative stress in the peritoneal cavity and endometriotic tissue, caused by retrograde menstruation and bleeding from endometriosis lesions, further contributes to the inflammatory environment. The phagocytic capacity of peritoneal macrophages is compromised by the abundance of erythrocytes regurgitated into the pelvis during monthly reflux. The release of hemoglobin, heme, and catalytic iron, along with forming reactive oxygen species, can result in cytotoxicity and genotoxicity [ 9 ]. Proinflammatory cytokines, which are synthesized and released by activated macrophages and mast cells in endometriotic lesions, play a role in the pathogenesis of endometriosis. Inflammatory cytokines, such as IL-1β, are elevated in patients with DIE compared to those with superficial endometriosis and normal women, suggesting their involvement in the pathophysiology of endometriosis [ 10 ]. These changes resemble those seen in adenomyosis and can affect multiple regions, including the rectovaginal septum and retroperitoneum. It is important to note that the peritoneal environment plays a crucial role in developing and progressing different types of endometriosis [ 11 ]. Studies have also explored the molecular mechanisms underlying endometriosis, including identifying common and specific gene signatures among different subtypes of endometriosis [ 12 ]. These studies provide insights into the molecular pathways involved in the development and progression of endometriosis. Endometrial glands and stroma infiltrate the surrounding fibromuscular tissue, but typically stop at the boundary of the underlying adipose tissue [ 13 ]. This infiltration is associated with hyperplasia of the surrounding smooth muscle and fibrous tissue. Ectopic microhemorrhages that persist despite fibrotic burial can lead to distinctive bluish nodules and a desmoplastic reaction, which causes strong adhesion and immobility of surrounding organs and ligaments [ 14 ]. Micro-endometriomas, ranging from 0.5 to 2 mm in diameter, are often found in the submucosal layer of the vagina, rectum, or bladder and are closely associated with deep infiltrating endometriosis [ 7 ]. While two nodules can occasionally appear, three nodules are extremely rare. Most deep endometriotic nodules are distinct and can reach sizes larger than 2 cm, often extending to the muscular layer of the bowel and occasionally located laterally to the ureters [ 15 ]. Organic pain, such as profound dyspareunia, arises from pressure on nodules and plaques, traction of inelastic tissues, and immobility of pelvic structures [ 14 ]. In addition to organic pain, endometriosis can cause functional pain, typically cyclic, and associated with releasing inflammatory mediators such as prostaglandins and cytokines. This can result in hyperalgesia, where individuals experience acute pain in response to non-painful stimuli [ 16 ]. In recent years, increasing attention has been paid to the complex interplay between DIE and adenomyosis. Both share pathophysiological mechanisms and frequently coexist, leading to more severe clinical manifestations, including chronic pelvic pain, infertility, and treatment resistance. Leyendecker et al. proposed a unifying theory based on the “tissue injury and repair” (TIAR) mechanism, in which repetitive uterine hyperperistalsis induces micro traumatization at the endometrial–myometrial interface, particularly at the fundo-cornual raphe [ 17 ]. This chronic injury leads to local estradiol production via upregulation of aromatase (P450arom) and estrogen receptor-β, contributing to a self-perpetuating cycle of inflammation and proliferative activity. As basal endometrial fragments dislocate transtubally or infiltrate the myometrium, they form ectopic foci resulting in endometriosis or adenomyosis, respectively. The shared origin and progression pathways of these diseases suggest they are not isolated entities but rather phenotypic variants of a common pathogenic process. Therefore, adenomyosis must be considered within the pathophysiological discussion of DIE, as it significantly influences symptomatology, surgical planning, and therapeutic outcomes [ 18 ].

Nerve-infiltrating deep endometriosis represents one of the most debilitating subtypes of endometriosis. It primarily involves the inferior hypogastric plexus, sacral nerve roots (S2–S4), and pelvic splanchnic nerves, leading to a spectrum of neuropathic symptoms including chronic pelvic pain, sciatica-like pain, dysuria, and altered bowel habits [ 93 ]. Preoperative identification remains challenging, though MRI neurography and pelvic nerve mapping are emerging as useful tools [ 94 ] . Surgical excision of nerve-infiltrating deep endometriosis lesions is technically demanding due to the risk of bladder atony, sexual dysfunction, or fecal incontinence. Thus, nerve-sparing techniques have become the cornerstone of modern surgical management. Laparoscopic nerve-sparing dissection allows selective removal of lesions while preserving critical autonomic fibers. Robotic-assisted nerve-sparing surgery offers enhanced magnification and instrument precision, minimizing iatrogenic nerve damage and improving functional outcomes [ 95 , 96 ] . Several studies have shown that a nerve-sparing approach is associated with significantly better postoperative urinary and anorectal function compared to radical excision [ 97 ]. However, the risk of incomplete resection and disease recurrence must be weighed against functional preservation.

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