Femoral hernia is not as common as inguinal hernia. It is often associated with incarceration or strangulation, resulting in peritonitis and mortality.
The pelvicrural interval (the opening from the abdomen to the thigh) is divided into two spaces: a lateral space, the lacuna musculosa, through which the iliopsoas muscles pass; and a medial space, the lacuna vasculosa, for the femoral vessels. The external iliac vessels run along the anterior surface of the iliopsoas muscle in the pelvis, pass between the iliopubic tract and Cooper’s ligament, and finally course beneath the inguinal ligament to become the femoral vessels. Where the external iliac vessels run down into the lacuna vasculosa, transversalis fascia covers the vessels to form the femoral sheath. It extends approximately 4 cm caudally and ends as the adventitia of the femoral vessels. The medial compartment of the femoral sheath is called the femoral canal, which is ordinarily less than 2 cm in diameter and contains lymphatic vessels and glands. The true opening of the femoral canal is a musculoaponeurotic ring, consisting of Cooper’s ligament inferiorly, the femoral vein laterally, and iliopubic tract superiorly and medially. In the past, the medial border of the femoral ring was for the lacunar ligament. The lacunar ligament is an attachment of the inguinal ligament to the pubic bone, however, and lies in the outer layer of the transversalis fascia.
McVay demonstrated that the medial boundary of the femoral ring is the lateral edge of the aponeurosis of the insertion of the transversus abdominis muscle with transversalis fascia onto the pectin of the pubis, not the lacunar ligament. Condon also demonstrated that the iliopubic tract bridges the femoral canal and then curves posteriorly and inferiorly, its fibers spreading fanwise to insert adjacent to Cooper’s ligament into a broad area of the superior ramus of the pubis. Thus, the true inner ring of the femoral canal is bounded by the iliopubic tract anteriorly and medially, and by Cooper’s ligament posteriorly. If a surgeon incises the inguinal ligament in a tightly incarcerated femoral hernia, he or she will find that the hernia cannot be reduced because of the more deeply placed ring. The distal orifice has a rigid boundary—surrounded by the lacunar ligament medially; the inguinal ligament superiorly; and the fascia of the pectineal muscle—and is usually less than 1 cm in diameter. The rigidity of these structures is the reason why strangulation often occurs in femoral hernias.
Currently, the ‘‘acquired’’ theory is widely accepted; however, the true cause of femoral hernia is not known. McVay demonstrated that the width of the femoral ring, which is determined by the length of the fanwise insertion of the iliopubic tract to Cooper’ ligament, is the main etiologic factor of the femoral hernia. Considering that the femoral hernia is very rare in children and most common in elderly women, however, McVay’s concept cannot be the only reason for the occurrence of femoral hernia. Nyhus noted the presence of a relatively large femoral defect without an accompanying femoral hernia during the preperitoneal approach. This may be caused by the acquired weakness of the transversalis fascia and a consequent predisposition to the development of the femoral hernia.
The ratio of femoral hernia relative to all groin hernias is reported to be 2% to 8% in adults . Femoral hernias are very rare in children, and most commonly observed between the ages of 40 and 70. The peak distribution is in the 50s, with a slight decrease in the 60s and 70s. As for sex distribution, femoral hernia is 4 to 5 times more common in female than in male; however, there are some reports that it is more common in men than in women. A right-sided presentation is more common than left, but the reason is not known.
Finally, femoral hernia is usually thought of as requiring emergency surgical treatment. Only 30% of our cases were treated as emergency operations, however, whereas 70% were elective. Unless patients complain of severe abdominal pain or ileus, surgeons need not perform emergency operations. In summary, the mesh plug hernia repair for femoral hernia has resulted in a reduced recurrence rate, shortened hospital stay, and a low rate of postoperative complications.
The incidence of recurrence in incisional hernia prosthetic surgery is markedly lower than in direct plasties. Indeed after the autoplasties of the preprosthetic period, the recurrence rate ranged from 35% for ventral hernias. Chevrel and Flament, in 1990, reported on 1,033 patients who had undergone laparotomy. The recurrence rate at 10-year follow-up was 14–24% for patients treated without the use of prostheses but only 8.6% for those in whom a prosthesis was implanted. A similar incidence was reported by Chevrel in 1995: 18.3% recurrence without prostheses, 5.5% with prostheses. Likewise, Wantz, in 1991, noted a recurrence rate of 0–18.5% in prosthetic laparo-alloplasties.
At the European Hernia Society (EHS)-GREPA meeting in 1986, the recurrence rate without prostheses was reported to be between 7.2 and 17% whereas in patients who had been treated with a prosthesis the recurrence was between 1 and 5.8%. A case study published by Flament in 1999 showed a 5.6% recurrence rate for operations with prostheses placed behind the muscles and in front of the fascia, and a 3.6% of such figure consisted of a small-sized lateroprosthetic recurrence. These rates were in contrast to the 26.8% recurrence reported by other surgeons for operations without prostheses.
Studies of recurrence are, of course, influenced by the size of the initial defect and the length of follow-up. Nevertheless, it is beyond dispute that the use of prostheses is associated with a lower rate of recurrence independent of the nature of the incisional hernia. The factors that lead to relapse are recognisable in the original features of the ventral hernia, i.e. combined musculo-aponeurotic parietal involvement, septic complications in the first operation, the nature and appropriateness of treatment, the kind of prosthesis and its position. Also important is whether the surgery was an emergency case and the relation to occlusive phenomena, visceral damage
and whether these problems were addressed at the same time.
Obesity is also an important risk factor for recurrence. In addition to its association with a higher surgical complications rate, related to the high intraabdominal pressure, there are deficits in wound cicatrisation as well as respiratory and metabolic pathologies. In such patients, the laparoscopic approach is very useful to significantly reduce the onset of general and wall complications, and the data concerning recurrence are encouraging, ranging between 1 and 9% in the largest laparoscopic case studies. The important multicentric study of Heniford et al., in 2000, reported a recurrence rate of 3.4% after 23 months. In 2003, the same author, in a study with an average follow-up of 20 months (range 1–96) showed a recurrence rate of 4.7% for different, identifiable causes: intestinal iatrogenic injuries and mesh infection with its removal, insufficient fixation of the prosthesis and abdominal trauma in the first postoperative period.
The incidence of recurrence after laparoscopic treatment may also be related to general patient factors and to the onset of local complications, mistakes in opting for laparoscopic treatment and deficits in implanting and fixing the prosthesis. With respect to the latter, it is very important to allow a large overlap compared to the diameter of the defect. Long-term data analysis, with large case studies, is still needed to obtain detailed information about recurrence, and this is particularly true in the assessment of relatively new techniques.
In both the UK and the USA the annual death rate due to inguinal and femoral hernia has decreased in the last two to three decades. In the UK, deaths for inguinal and femoral hernia declined from 22 to 55% respectively from 1975 to 1990. The annual deaths in the USA per 100,000 population for patients with hernia and intestinal obstruction decreased from 5.1 in 1968 to 3.0 in 1988. For inguinal hernia with obstruction, 88% of patients underwent surgery with a mortality rate of 0.05%. These figures could be interpreted as showing that elective groin hernia surgery has reduced overall mortality rates.
In support of this contention is the fact that strangulation rates are lower in the USA than in the UK, which could be a consequence of the three times higher rate of elective hernia surgery in the USA. Even so, the available statistics show that rates of elective hernia surgery in the USA per 100,000 population fell from 358 to 220 between 1975 and 1990, although this may be an artifact of the data collection systems rather than a real decline.
During the period 1991–1992, 210 deaths occurring following inguinal hernia repair and 120 deaths following femoral hernia repair were investigated by the UK National Confidential Enquiry Into Perioperative Deaths. This enquiry is concerned with the quality of delivery of surgery, anesthesia, and perioperative care. Expert advisers compare the records of patients who have died with index cases. In this group of 330 patients many were elderly (45 were aged 80–89 years) and significantly infirm unfit; 24 were ASA grade III and 21 ASA grade IV. Postoperative mortality was attributed to preexisting cardiorespiratory problems in the majority of cases. In a nationwide study in Denmark of 158 patients dying after acute groin hernia repair, Kjaergaard et al. also found that these patients were old (median age 83 years) and fragile (>80% with significant comorbidity), with frequent delay in diagnosis and subsequent treatment. Clearly this group of patients requires high-quality care by an experienced surgeon and anesthetist with skills equivalent to that of the ASA grade of the patient.
Postoperative care should necessarily take place in a high-dependency unit or intensive therapy unit; this may necessitate transfer of selected patients to appropriate hospitals and facilities. Sensible decisions must be made in consultation with relatives of extremely elderly, frail, or moribund patients to adopt a humane approach, which may rule out interventional surgery.
Forty percent of patients with femoral hernia are admitted as emergency cases with strangulation or incarceration, whereas only 3% of patients with direct inguinal hernias present with strangulation. This clearly has implications for the prioritization on waiting lists when these types of hernia present electively to outpatient clinics. A groin hernia is at its greatest risk of strangulation within 3 months of its onset. For inguinal hernia at 3 months after presentation, the cumulative probability of strangulation is 2.8%, rising to 4.5% after 2 years. For femoral hernia the risk is much higher, with a 22% probability of strangulation at 3 months after presentation rising to 45% at 21 months. Right-sided hernias strangulate more frequently than left-sided hernias; this is possibly related to mesenteric anatomy.
In a randomized trial, evaluating an expectative approach to minimally symptomatic inguinal hernias, Fitzgibbons et al. in the group of patients randomized to watchful waiting found a risk of an acute hernia episode of 1.8 in 1,000 patient years. In another trial, O’Dwyer and colleagues, randomizing patients with painless inguinal hernias to observation or operation, found two acute episodes in 80 patients randomized to observation. In both studies, a large percentage of patients randomized to nonoperative care were eventually operated due to symptoms. Neuhauser, who studied a population in Columbia where elective herniorrhaphy was virtually unobtainable, found an annual rate of strangulation of 0.29% for inguinal hernias.
Management of Strangulation
Diagnosis is based on symptoms and signs supplemented by diagnostic imaging when indicated. Pain over the hernia site is invariable, and obstruction with strangulation of intestine will cause colicky abdominal pain, distension, vomiting, and constipation. Physical examination may reveal degrees of dehydration with or without CNS depression, especially in the elderly if uremia is present, together with abdominal signs of intestinal obstruction. Femoral hernias can be easily missed, especially in the obese female, and a thorough examination should be performed in order to make the correct diagnosis. Frequently, however, physical examination alone is insuf fi ciently accurate to con fi rm the presence of a strangulating femoral hernia vs. lymphadenopathy vs. a lymph node abscess. In these instances, one may elect to perform radiographic studies such as an ultrasound or a CT scan on an urgent or emergent basis.
The choice of incision will depend on the type hernia if the diagnosis is confi dent. When the diagnosis is in doubt, a half Pfannenstiel incision 2 cm above the pubic ramus, extending laterally, will give an adequate approach to all types of femoral or inguinal hernia. The fundus of the hernia sac can then be approached and exposed and an incision made to expose the contents of the sac. This will allow determination of the viability of its contents. Nonviability will necessitate conversion of the transverse incision into a laparotomy incision followed by release of the constricting hernia ring, reduction of the contents of the sac, resection, and reanastomosis. Precautions should be taken to avoid contamination of the general peritoneal cavity by gangrenous bowel or intestinal contents. In the majority of cases, once the constriction of the hernia ring has been released, circulation to the intestine is reestablished and viability returns. Intestine that is initially dusky, aperistaltic, or dull in hue may pink up with a short period of warming with damp packs once the constriction band is released. If viability is doubtful, resection should be performed. Resection rates are highest for femoral or recurrent inguinal hernias and lowest for inguinal hernias. Other organs, such as bladder or omentum, should be resected, as the need requires. After peritoneal lavage and formal closure of the laparotomy incision, specific repair of the groin hernia defect should be performed. In this situation prosthetic mesh should not be used in an operative fi eld that has been contaminated and in which there is a relatively high risk of wound infection. The hernia repair should follow the general principles for elective hernia repair. It should be kept in mind, that in this group of predominantly frail and elderly patients with a very high postoperative mortality risk, the primary objective of the operation is to stop the vicious cycle of strangulation, and only secondary to repair the hernia defect.
The risk of an acute groin hernia episode is of particular relevance, when discussing indication for operation of painless or minimally symptomatic hernias. A sensible approach in groin hernias would be, in accordance with the guidelines from the European Hernia Society to advise a male patient, that the risk of an acute operation, with an easily reducible (“disappears when lying down”) inguinal hernia with little or no symptoms, is low and that the indication for operation in this instance is not absolute, but also inform, that usually the hernia after some time will cause symptoms, eventually leading to an operation. In contrast, female patients with a groin hernia, due to the high frequency of femoral hernias and a relatively high risk of acute hernia episodes, should usually be recommended an operation.
Since the introduction of polypropylene (PP) mesh for hernia repair, surgeons continue to discuss the use of mesh in a variety of settings for one of the most common operations performed by general surgeons—hernia repair. This discussion has involved raw materials, cost, and outcomes and for many years referred to only a few products, as manufacturing was limited. Nowadays, with multiple permanent, absorbable, biologic, and hybrid products on the market, the choice of mesh for a hernia repair can be daunting. Increasing clinical complexity further emphasizes the need for individualizing care, but more frequently, hospital supply chain personnel institute product procurement procedures for cost control, limiting mesh choice for surgeons. This can force surgeons into a “one-size-fits-all” practice regarding mesh choice, which may not be ideal for some patients. Conversely, current literature lacks definitive evidence supporting the use of one mesh over another, a fact that has not escaped the radar screen of the hospital supply chain and mesh industry, both of which attempt to limit vendor and mesh choice for financial gain. It is unlikely that this type of “proof” will ever come to fruition. This leaves us with choosing a mesh based on an algorithm that is centered on the patient and the patient’s unique clinical scenario.
A hernia is a weakness or disruption of the fibromuscular tissues through which an internal organ (or part of the organ) protrudes or slides through. Collectively, inguinal and femoral hernias are often lumped together into groin hernias. Surgery remains the only effective treatment, but the optimal timing and method of repair remain controversial. Although strangulation rates of 3% at 3 months have been reported by some investigators, the largest prospective randomized trial of (watchful waiting) men with minimally symptomatic inguinal hernias showed that watchful waiting is safe. Frequency of strangulation was only 2.4% in patients followed up for as long as 11.5 years. Long-term follow-up shows that more than two-thirds of men using a strategy of watchful waiting cross over to surgical repair, with pain being the most common reasons. This risk of crossover is higher in patients older than 65 years. Once an inguinal hernia becomes symptomatic, surgical repair is clearly indicated. Femoral hernias are more likely to present with strangulation and require emergency surgery and are thus repaired even when asymptomatic. Because this article focuses on incarcerated hernias, nonoperative options are not discussed.