INTRODUCTION — Recurrence rates for primary hernia repair range from 0.5 to 15 percent depending upon the hernia site (direct, indirect, femoral), type of repair (mesh, no mesh, open, laparoscopic), and clinical circumstances (elective, emergency) [1-5]. Hernia recurrence is less common with repair of inguinal compared with femoral hernia repair due to the higher rates of emergency surgery and complications associated with femoral hernia [6,7].

The indications for recurrent inguinal and femoral hernia repair are similar to those of primary inguinal and femoral hernia repair. Most symptomatic patients should undergo repair; however, some minimally symptomatic male patients can be safely observed. The choice of technique for repair of recurrent inguinal hernia is largely anatomically based, depending upon the nature of the prior hernia repair. In general, failed posterior repairs (eg, laparoscopic) should be repaired using an anterior approach, and vice versa, failed anterior repairs (eg, Lichtenstein repair) should be repaired using a posterior approach [8]. Repair of recurrent inguinal hernias can be more complicated than primary inguinal hernia repair and is associated with higher rates of recurrence (ie, re-recurrence) and other complications [9,10].

Recurrent inguinal hernia will be reviewed here. The clinical features, diagnosis, and management of inguinal and femoral hernia in adults and children, and repair techniques (open, laparoscopic), are discussed elsewhere. (See "Overview of treatment for inguinal and femoral hernia in adults" and "Inguinal hernia in children" and "Open surgical repair of inguinal and femoral hernia in adults" and "Laparoscopic inguinal and femoral hernia repair in adults".)

DEFINITIONS AND RECURRENCE SITE — Inguinal and femoral hernias are classified according to their etiology and anatomic site. A primary etiology for hernia is related to congenital tissue abnormalities, whereas a secondary hernia etiology is related to acquired tissue abnormalities (eg, trauma). (See "Classification, clinical features, and diagnosis of inguinal and femoral hernias in adults".)

●Primary hernia repair – A primary hernia repair refers to the initial or index hernia repair. Primary hernia repair should not be confused with repair of a primary hernia (as compared with a secondary hernia), as classified by etiology.

●Recurrent hernia – A recurrent inguinal hernia is one that is directly related to the primary hernia repair. An older term, secondary hernia repair, is out of favor [11].

●Re-recurrent hernia – Re-recurrence refers to the occurrence of a hernia that has been repaired at least twice before.

●Neglected hernia – We will use the term neglected hernia to refer to a hernia that was not identified prior to or during the course of repair of another hernia (primary, recurrent, or re-recurrent hernia repair) and thus was not repaired. These hernias do not technically represent a recurrence; however, they contribute to hernia repair outcomes.

Anatomic site of recurrence — The anatomic site of recurrence after inguinal hernia repair can be located anatomically at either a direct (medial to the inferior epigastric vessels within Hesselbach's triangle), indirect (lateral to the inferior epigastric vessels), or femoral site (inferior to the inguinal ligament) (figure 1 and figure 2 and figure 3).

Following open inguinal hernia repair (mesh or non-mesh), the most common anatomic recurrence site is a direct hernia [12,13]. Following Lichtenstein repair, a higher-than-expected rate of femoral recurrence has been reported [13,14]. In a study of 34,849 groin hernia repairs, a 15-fold greater incidence relative to the spontaneous incidence of femoral hernia was reported after inguinal herniorrhaphy [14]. These femoral recurrences tended to occur earlier than inguinal site recurrences, leading the authors to speculate these were neglected or missed femoral hernias that were not treated at the time of primary repair. (See "Open surgical repair of inguinal and femoral hernia in adults".)

Following laparoscopic inguinal hernia repair, an indirect recurrence site is the most common anatomic site regardless of whether the initial repair was performed as a totally extraperitoneal (TEP) hernia repair or transabdominal preperitoneal (TAPP) hernia repair (figure 4) [15,16]. The mechanism is unclear but may be related to inadequate dissection of the spermatic cord or, alternatively, herniation of the sac beneath the mesh due to mesh migration, inadequate mesh size, inadequate mesh fixation, or subsequent mesh shrinkage. (See "Laparoscopic inguinal and femoral hernia repair in adults".)

EPIDEMIOLOGY AND RISK FACTORS FOR RECURRENT INGUINAL HERNIA — The rate of recurrence for inguinal hernia may be declining due to the more frequent use of mesh in primary hernia repairs. In a retrospective review from Olmsted County, Minnesota, the incidence of recurrent inguinal hernia decreased from 66/100,000 person-years to 26/100,000 person-years from 1989 to 2008 [17]. Risk factors for recurrent hernia can be related to the type of prior hernia and technical aspects of that repair, complications of repair such as infection, as well as patient- and surgeon-related factors [2,4,12,18].

Technical issues — The main technical factors associated with recurrent inguinal hernia include hernia repair under tension, most commonly due to non-mesh repair (ie, herniorrhaphy) [4,12,18] or inadequate mesh size or potentially inadequate mesh fixation (open or laparoscopic). Excessive dissection and devascularization can also lead to hernia recurrence. Not surprisingly, the recurrence rate is higher for repair of recurrent hernias (ie, re-recurrence) compared with repair of primary hernias related to increased complexity of recurrent hernia repair [9,12,18,19]. (See 'Re-recurrent hernia' below.)

Non-mesh hernia repair — Non-mesh repair, which is less likely to produce a tension-free repair, is an important cause of failed hernia repair. Provided mesh is used, no significant differences have been identified in the incidence of recurrent hernia following primary hernia repair, regardless of operative approach (ie, open versus laparoscopic hernia repair) [2,4,5,20,21]. (See "Overview of treatment for inguinal and femoral hernia in adults", section on 'Surgical techniques'.)

Inadequate mesh size or fixation — Another important technical risk factor for hernia recurrence is inadequate overlap at the margin of a hernia defect due to improper mesh sizing, positioning, or fixation. In a review of 32,206 hernias from the Swedish Hernia Registry and the Danish Hernia Database, the overall recurrence rate was 0.7 percent for Lichtenstein repair, which is an open mesh repair (figure 5) [13]. Most recurrences, which were direct hernias located at the pubic tubercle or along the medial edge of the repair, were technical failures attributed to inadequate mesh fixation and inadequate mesh overlap at the pubic tubercle. In one retrospective review of 1983 men undergoing laparoscopic or open (Lichtenstein) repair for primary or recurrent inguinal hernia, the higher recurrence rate for laparoscopic repair was attributed to a smaller size of mesh [21]. (See "Open surgical repair of inguinal and femoral hernia in adults", section on 'Mesh fixation' and "Laparoscopic inguinal and femoral hernia repair in adults", section on 'Mesh placement and fixation'.)

Missed cord lipoma — Herniation of retroperitoneal adipose tissue through the internal ring into the inguinal canal, commonly referred to as a "cord lipoma," is frequently encountered during inguinal hernia repair [22]. As an example, in a study of 498 patients undergoing total extraperitoneal (TEP) laparoscopic inguinal hernia repairs, 27 percent were found to have a cord lipoma [23]. Patients with obesity and those who have a large hernial defect are at a higher risk.

Cord lipomas encountered in the inguinal canal during open hernia repair should be resected. During laparoscopic (TEP) surgery, cord lipomas in the inguinal canal or the internal ring should either be resected or reduced to the pelvic peritoneal reflection line, followed by the placement of a mesh that separates the reduced lipomas and the internal ring [23].

Failure to recognize and manage a cord lipoma could result in recurrent hernia formation [24,25]. By one estimate, missed cord lipomas accounted for 30 to 50 percent of recurrent inguinal hernias following laparoscopic repair [26].

Type of anesthesia — Open mesh repairs can be performed using local, regional, or neuraxial anesthesia, whereas laparoscopic repairs usually require general anesthesia. Whether or not the type of anesthesia used at the time of hernia repair impacts the risk for recurrent inguinal hernia is controversial.

An increased risk for recurrent hernia was reported in the past for hernia repair using local anesthesia compared with general or regional anesthesia [27]. A later multivariate analysis using data from 59,823 hernia repairs from the Swedish Hernia Registry found an overall increased risk for recurrence when the repair was performed using local anesthesia compared with a regional or general anesthesia, a difference that was apparent for primary inguinal hernia repair but not for recurrent inguinal hernia repair [28]. In a review of the Danish Hernia Database (43,123 hernia repairs), there were no overall differences in the hernia recurrence rate (3.5 percent) based upon the type of anesthetic [29]. Although hernia recurrence was more common using a local anesthetic for direct (medial) versus indirect (lateral) hernia repair (7 versus 2 percent), this difference was attributed to the location of health care delivery. The rate of hernia recurrence was much lower at private hospitals, where local anesthetic use was uniform, compared with the university hospital setting.

Patient factors — Patient factors that increase the risk for recurrent inguinal hernia are generally those that disrupt or weaken the tissues, contribute to poor wound healing, or increase the risk for postoperative infection. The most important of these include [30-32] (see "Basic principles of wound healing"):

●Prior hernia repair

●Smoking

●Older age at initial hernia presentation

●Diabetes mellitus

●Obesity

●Renal insufficiency

●Deficiency of coagulation factor VIII or vitamin C

●Glucocorticoid therapy

●Chemotherapy

●Increased intra-abdominal pressure (eg, chronic cough, constipation, bowel distention)

Sex — Some studies have found higher hernia recurrence rates for women, while others report the opposite. In studies from the Danish Hernia Registry, the overall reoperation rate was 4.3 percent for women and 3.1 percent for men after 29 month follow-up [3,8]. However, with respect to inguinal hernia only, recurrence rates were 5 percent in men and 4 percent in women over five years [19]. Femoral hernias may be found more often at reoperation in women initially treated for direct or indirect inguinal hernia at the primary operation compared with men (42 versus 4.6 percent in one study [33,34]), suggesting a higher incidence of neglected hernia in women, rather than true recurrence.

Genetic factors may increase the tendency toward recurrent inguinal hernia. In a review of 75 patients with two or more inguinal hernia recurrences, 44 percent had a positive family history of hernia recurrence [31]. Possible mechanisms include a decreased ratio of type I/type III collagen and higher levels of matrix metalloproteinases (MMPs) [35-37].

Surgeon experience — Low recurrence rates can be achieved for a variety of techniques when the individual performing the surgery has sufficient experience with the specific technique [30,32]. Surgeon experience is particularly important with respect to performing laparoscopic inguinal hernia repair [20,38]. Laparoscopic inguinal hernia repair is complex, and the learning curve is more pronounced compared with open hernia repair. Unfortunately, laparoscopic hernia repair continues to be less frequently performed relative to open repair during surgical training, and additional training may be necessary. A Veterans Affairs study found that a case volume of <250 laparoscopic repairs, rather than a greater volume, was significantly associated with a higher risk for hernia recurrence (10 versus 5 percent) [21].

CLINICAL FEATURES — The clinical features of recurrent inguinal hernia are similar to those of primary inguinal hernia. The surgical technique used for primary hernia repair must be identified to plan recurrent hernia repair. Clinical examination by an experienced surgeon is usually sufficient for detecting recurrent inguinal hernia; however, imaging may be needed for patients with symptoms consistent with a recurrent inguinal hernia but for whom the physical examination does not clearly demonstrate a recurrent hernia. (See "Classification, clinical features, and diagnosis of inguinal and femoral hernias in adults", section on 'Identifying occult hernia'.)

On physical examination, systemic symptoms such as fevers, chills, malaise, local findings of pain on palpation, erythema, warmth, swelling, or drainage raise suspicion for mesh infection and alter the course of treatment in the patient with recurrent hernia. (See "Wound infection following repair of abdominal wall hernia".)

Timing of recurrence — Hernia recurrence can occur immediately, early, or late in the time course following hernia repair. Some authors have used five years to separate early from late recurrence, although a specific timeframe has not been firmly established [18,39].

●Immediate recurrence is likely due to technical issues, such as disruption of the repair due to excessive increases in intra-abdominal pressure or trauma. The use of prosthetic material has dramatically diminished technically related immediate recurrences. Some immediate recurrences are neglected/missed hernias that were not identified at the time of the initial operation.

●Early recurrence is generally related to technical (surgeon) factors [18]. The rate of early recurrent hernias can be minimized by avoiding undue tension, handling tissue gently to prevent devascularization, and preventing infection. Techniques for inguinal and femoral hernia repair are discussed elsewhere. (See "Open surgical repair of inguinal and femoral hernia in adults" and "Laparoscopic inguinal and femoral hernia repair in adults".)

●Late recurrences are related to hernia biology, aging, and other patient-related factors. Late recurrences continue to occur, but at a slightly decreased incidence. Specific recommendations such as weight loss in those who have obesity, cessation of smoking, and discontinuation of glucocorticoid therapy, if possible, may decrease the risk for hernia recurrence. (See 'Patient factors' above.)

The majority of recurrences occur within the first three years following hernia repair [12]. In a review of the Danish Hernia Database, 2.8 percent of reoperations were performed in the first 15 months following hernia repair, and 1.6 percent occurred in the subsequent 15 months [1]. In a later review of the Danish Hernia Registry, the mean time interval for recurrent hernia repair was 12.6 months for inguinal hernia and 10.3 months for femoral hernia [3]. The average time from the initial repair to the diagnosis of recurrence in a study focusing on laparoscopic hernia repair was 20 months (range 3 to 84) [16].

INDICATIONS FOR REPAIR — The indications and contraindications for repair of recurrent inguinal hernias are similar to those of the initial repair. (See "Overview of treatment for inguinal and femoral hernia in adults", section on 'Indications for surgical repair'.)

Urgent repair is indicated for patients with complications related to the hernia (strangulation, obstruction, perforation). Patients with an uncomplicated but symptomatic hernia should undergo elective hernia repair unless medical comorbidities are prohibitive.

Men with asymptomatic recurrent hernia can be safely observed given that the risk of acute incarceration is low. The watchful waiting trial, a trial that randomly assigned 720 men with a minimally symptomatic inguinal hernia to inguinal hernia repair or watchful waiting, included 77 patients (10.6 percent) with recurrent hernia, 43 of whom were assigned to watchful waiting [40]. The rate of hernia-related complications in the watchful waiting group was extremely low (1.8 per 1000 patient-years).

PREOPERATIVE PREPARATION — The preoperative preparation of the patient undergoing a recurrent inguinal hernia repair is similar to that of elective primary hernia. (See "Overview of treatment for inguinal and femoral hernia in adults", section on 'Preoperative preparation'.)

When a laparoscopic approach is chosen for recurrent inguinal hernia repair, general anesthesia is usually required. Although local or regional anesthesia is often used for open repair of primary hernia, we prefer to use general anesthesia or neuraxial anesthesia for recurrent inguinal hernia given the more extensive dissection that is usually needed. (See "Overview of anesthesia" and 'Type of anesthesia' above.)

MESH FOR RECURRENT HERNIA — More than 90 percent of surgeons in the United States incorporate mesh as a component of a tension-free repair to reduce the risk for recurrence [5,41]. The use of mesh to provide additional tissue support seems appropriate given that recurrent inguinal hernia may be linked to altered extracellular matrix biology [37].

The use of mesh appears to be equally important for the repair of recurrent inguinal hernia. In a review of the Danish Hernia Database, among 2117 patients with hernia recurrence, 3.1 percent (187 patients) had re-recurrence following recurrent repair [9]. Following primary hernia repair using a Lichtenstein technique, a significantly lower rate of re-recurrence was found in patients who underwent subsequent mesh repair compared with non-mesh repair. The re-recurrence rates were as follows:

●Laparoscopic (mesh): 1.3 percent

●Mesh (non-Lichtenstein): 7.2 percent

●Lichtenstein: 11.3 percent

●Non-mesh: 19.2 percent

There is a paucity of data about the preferred type of mesh for recurrent hernia repair. We use polypropylene mesh in most cases, but if the mesh cannot be covered with peritoneum and will be exposed to the intestinal contents, we substitute expanded polytetrafluoroethylene (ePTFE) or coated polypropylene mesh. There are insufficient data on the long-term durability of biologic mesh in recurrent inguinal hernia.

APPROACH TO RECURRENT INGUINAL HERNIA REPAIR — Inguinal hernias should be repaired using a tension-free mesh repair whenever possible [8]. (See 'Mesh for recurrent hernia' above.)

The previous mesh should be left in place, provided it is well incorporated, there is no evidence for infection, and it is not felt to be a source of chronic groin pain. The management of neuralgia following hernia repair and recurrent hernia related to mesh infection, which requires mesh removal, is discussed elsewhere. (See "Post-herniorrhaphy groin pain", section on 'Mesh removal' and "Wound infection following repair of abdominal wall hernia".)

Similar techniques are used to repair recurrent inguinal hernia as are used to repair primary inguinal hernia; however, repair of recurrent inguinal hernia can be more challenging and has a greater risk for complications [10,30,42]. (See "Overview of complications of inguinal and femoral hernia repair".)

The most common techniques used to repair recurrent inguinal hernia are the laparoscopic totally extraperitoneal (TEP), laparoscopic transabdominal preperitoneal (TAPP) patch, Lichtenstein, plug and patch mesh repairs, and robot-assisted repair. The choice of technique is largely anatomically based, depending upon the nature of the prior hernia repair, given that no significant differences in re-recurrence rates have been demonstrated in randomized trials comparing open and laparoscopic techniques for recurrent hernia repair [20,43-48]. However, laparoscopic techniques have the advantages of less pain and a quicker recovery [10,42]. Each of the above techniques for inguinal hernia repair, including important technical points for recurrent inguinal hernia repair using the Lichtenstein and laparoscopic techniques, is discussed elsewhere. (See "Laparoscopic inguinal and femoral hernia repair in adults", section on 'Techniques for recurrent hernia repair' and 'Re-recurrent hernia' below.)

Open versus laparoscopic repair — For the repair of primary hernia, recurrence rates for open versus laparoscopic repair are similar, provided mesh is used. Similarly, meta-analyses of randomized trials have found no significant differences in hernia re-recurrence for tension-free mesh repair of recurrent hernia using an open versus laparoscopic technique [10,42,49,50]. (See "Overview of treatment for inguinal and femoral hernia in adults", section on 'Choosing a surgical approach'.)

A meta-analysis of four randomized trials [20,43-45] that included 404 patients with recurrent inguinal hernia evaluated tension-free, open, mesh, and laparoscopic (mesh) repairs [42]. Open mesh repairs included the Lichtenstein and giant prosthesis for reinforcement of the visceral sac (GPRVS) techniques. TEP and TAPP procedures were used for laparoscopic repair. Primary outcomes included the rate of re-recurrence and chronic pain. Secondary outcomes included postoperative pain, superficial wound infection, operating time, time to return to daily activities, wound seromas or hematomas, and complications requiring additional surgical procedures. The following findings were noted [42]:

●In a pooled analysis, there were no significant differences between laparoscopic and open hernia repair for the primary outcomes of re-recurrence (odds ratio [OR] 0.84, 95% CI 0.33-2.17) or chronic pain (OR 0.91, 95% CI 0.14-5.88).

●Laparoscopic repair was associated with significantly less postoperative pain (OR 0.58, 95% CI 0.31-0.84), fewer superficial wound infections (OR 0.29, 95% CI 0.08-0.96), and shorter time to return to daily activities and work (weighted mean difference [WMD] 0.82 days, 95% CI 0.36-1.27 days) but longer operative times (WMD 0.68 min, 95% CI 0.23-1.13). There were no differences identified for wound seroma or hematoma or the need for additional surgical procedures.

A separate meta-analysis that combined the results of five randomized trials [43,44,46-48] and seven other studies (five retrospective and two prospective) assessed outcomes in 1542 patients with recurrent hernias repaired using laparoscopic (TEP or TAPP) or open (Lichtenstein or preperitoneal) techniques [10]. No significant differences were seen for early re-recurrence (relative risk [RR] 0.73, 95% CI 0.21-2.51) or overall re-recurrence (RR 0.72, 95% CI 0.45-1.15). No differences were seen for the various techniques for postoperative wound infection, urinary retention, testicular pain/discomfort, or neuralgia. Comparing laparoscopic techniques, the risk of overall re-recurrence was significantly higher for laparoscopic TAPP compared with TEP technique (RR 3.25, 95% CI 1.32-7.90). Because of insufficient data, no comparisons were made between TAPP and Lichtenstein, TEP and preperitoneal, or TAPP and preperitoneal. A subsequent meta-analysis that included two additional randomized trials comparing open versus laparoscopic repair found similar results [49].

A large retrospective review of 19,582 operations for recurrent hernia compared laparoscopic repair with other techniques (eg, suture closure, Lichtenstein, plug) [12]. The laparoscopic and open mesh approaches were significantly associated with the lowest rates of re-recurrence following prior open (anterior) repair; however, no technique differed significantly for recurrent hernia repair following prior preperitoneal repair (laparoscopic or preperitoneal [open]).

Suggested approach — With respect to the risk for re-recurrence, open and laparoscopic repair of recurrent hernia appear equivalent (as discussed in the section above); thus, we use an anatomic approach that avoids previously dissected tissue planes. Most open repairs are performed anterior to the hernia defect (except the uncommonly performed Kugel repair), and laparoscopic repair is performed posterior to the hernia defect. Thus, in general, failed posterior repairs should be repaired using an anterior approach, and vice versa, failed anterior repairs should be repaired using a posterior approach [8].

●For patients with a failed posterior repair (eg, laparoscopic, preperitoneal), a Lichtenstein repair, which has been shown to be superior to other open, anterior repairs, should be used. However, a standard Lichtenstein repair cannot be used if the hernia recurrence is at the femoral site. Under this circumstance, an infrainguinal mesh plug repair or a modified Lichtenstein repair can be used. (See "Open surgical repair of inguinal and femoral hernia in adults", section on 'Choice of repair' and "Open surgical repair of inguinal and femoral hernia in adults", section on 'Recurrent hernia'.)

●For patients with a failed anterior mesh repair (eg, Lichtenstein), a laparoscopic TEP or TAPP repair should be used preferentially over an open preperitoneal approach because laparoscopic repair is associated with fewer perioperative complications and less postoperative pain. Moreover, in the laparoscopic era, more surgeons would be comfortable with the laparoscopic approach compared with the open preperitoneal repair technique. A particular laparoscopic technique (ie, TEP or TAPP) may have advantages under specific clinical circumstances, but for most patients, we suggest a TEP approach, which appears to be associated with a lower risk of re-recurrence following recurrent hernia repair compared with TAPP (discussed in the previous section). However, for patients with prior pelvic surgery, for which TEP repair may not be possible, either a laparoscopic or robotic TAPP or open preperitoneal repair can be used. When the exact location of the recurrent hernia is unclear, a laparoscopic or robotic TAPP approach allows all potential hernia defects (eg, direct, indirect, and femoral) to be seen [16]. For patients with a failed anterior repair performed without mesh, an anterior mesh repair (eg, Lichtenstein) may also be an acceptable option; however, given the challenges of dissection in a reoperative field, most surgeons prefer a laparoscopic approach. (See "Laparoscopic inguinal and femoral hernia repair in adults", section on 'Choice of procedure: TEP or TAPP?' and "Laparoscopic inguinal and femoral hernia repair in adults", section on 'Techniques for recurrent hernia repair'.)

Re-recurrent hernia — In a review of the Danish Hernia Database, 187 patients among 2117 (8.8 percent) who underwent repair of a recurrent hernia had a failed repair (ie, re-recurrence) [9]. In a longer-term study, the rate of re-recurrence was 29 percent after a median of 5.5 years [19]. Patients who experience repeat hernia recurrences may have abnormally weakened tissues that can be explained by biologic or genetic factors. (See 'Patient factors' above.)

For patients with recurrent hernia after both anterior and posterior mesh repairs, the choice of procedure depends upon the location of the hernia and the skill set of the surgeon. For a small, medial direct hernia re-recurrence, repair with minimal dissection using an open anterior approach with placement of a mesh plug in the defect is an effective low-risk approach.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Groin hernia in adults".)

SUMMARY AND RECOMMENDATIONS

●Recurrence rates for primary inguinal hernia repair range from 0.5 to 15 percent depending upon the hernia site (direct, indirect) and type of repair (mesh, no mesh, open, laparoscopic). Risk factors associated with a failed primary inguinal hernia repair include the site of the prior hernia repair, technical issues (eg, non-mesh repair, inadequate mesh), patient-related factors (eg, inherited collagen deficiency, medication), and surgeon experience. (See 'Epidemiology and risk factors for recurrent inguinal hernia' above.)

●The clinical features of recurrent inguinal hernia are similar to those of primary inguinal hernia. Clinical examination by an experienced surgeon is usually sufficient for detecting recurrent inguinal hernia; however, imaging may be needed in patients with symptoms consistent with a recurrent inguinal hernia but for whom the physical examination does not clearly demonstrate a recurrent hernia. (See "Classification, clinical features, and diagnosis of inguinal and femoral hernias in adults", section on 'Identifying occult hernia'.)

●Hernia recurrence can occur immediately, early (within five years following hernia repair), or late (more than five years after hernia repair) in the time course following hernia repair. Immediate and early recurrences are usually due to technical problems, whereas later recurrences are more often related to patient-related factors that alter wound biology. (See 'Timing of recurrence' above.)

●Repair of recurrent inguinal hernia is challenging, and failure rates are higher compared with primary hernia repair. Re-recurrence following recurrent inguinal hernia repair can be as high as 20 percent, depending on the time course of follow-up, but is independent of approach (ie, open or laparoscopic). (See 'Re-recurrent hernia' above and 'Open versus laparoscopic repair' above.)

●For repair of recurrent inguinal hernia, we use an anatomic approach that avoids previously dissected tissue planes. In general, failed posterior repairs should be repaired using an anterior approach, and vice versa, failed anterior repairs should be repaired using a posterior approach [20,38]. (See 'Suggested approach' above.)

•For patients with recurrent inguinal hernia previously repaired by a posterior approach, we suggest a Lichtenstein repair, rather than other open anterior techniques (Grade 2C).

•For patients with recurrent inguinal hernia previously repaired by an anterior approach, we suggest a laparoscopic approach, rather than an open preperitoneal approach (Grade 2C). We further suggest a totally extraperitoneal (TEP) preperitoneal hernia repair over the transabdominal preperitoneal (TAPP) hernia repair approach, when anatomically feasible (Grade 2C).

●As with repair of primary hernia, the approach that is ultimately used to repair recurrent inguinal and femoral hernia should be the one the surgeon is most comfortable with and is the most experienced performing. Although a particular approach may be preferred, surgeons without experience with one particular approach may choose an alternative approach or refer the patient to another surgeon. (See 'Surgeon experience' above.)