Groin hernia are very common and surgical treatment is recommended for the majority of patients. Groin hernia repair is the commonest general surgical procedure in the UK. Despite the gradual move to day-case procedures, waiting times for surgery have increased.
Groin hernia are types of abdominal hernia. There are three types of groin hernia, classified according to the anatomical defect: direct and indirect inguinal hernia and femoral hernia. Femoral hernia are more likely to strangulate than are inguinal hernia, and indirect inguinal hernia are more likely to strangulate than are direct. It is usually possible to distinguish clinically between inguinal and femoral hernia, but distinguishing between indirect and direct inguinal hernia is less reliable.
Groin hernia are more common in men than in women, and become increasingly common with advancing age. Up to one in four men will develop a groin hernia at some stage.
There are three treatment options: make a surgical repair, supply a truss or 'do nothing'. Surgery is recommended for all groin hernia in children and for femoral hernia in adults. Surgery is also the appropriate choice for most adults with indirect hernia, to relieve symptoms and to reduce the risk of serious complications. 'Do nothing' may be the best option in elderly males with a symptom-free direct hernia.
In NHS hospitals in England in 1995–96, there were 87, 700 inguinal hernia repairs and 5150 femoral repairs.
There has been a steady rise in the number of inguinal hernia repairs performed since the late 1980s, with a fall in the numbers of procedures classified as an emergency. Waiting times have increased (median wait 85 days) and there is a wide variation between health authorities. In 1995–96, just under one-third of such repairs were performed as day cases.
The number of femoral hernia repairs has remained steady, with a slight fall in the numbers classified as an emergency. The percentage of repairs performed as an emergency remains high at 43.7%. Waiting times have also increased (median wait 47 days) and the percentage of procedures performed as day cases is low at 11.9%.
There are no studies examining the outcomes of conservative treatment, although a randomised trial is being conducted in the USA and results will be available in 2–3 years' time. There is no evidence to support the use of trusses for definitive treatment, but they may alleviate symptoms while a patient awaits an operation.
In the main, studies of effectiveness examine the effect of different surgical techniques for inguinal hernia repair. There are no rigorous trials examining techniques of femoral hernia repair. Other issues that may alter the effectiveness of a procedure include the skill or experience of the surgeon, advice given about mobilisation, the type of anaesthetic used and the volume of hernia that a unit treats.
Randomised controlled trials (RCTs) have mostly examined different surgical techniques. The current debate is between open-mesh repairs and extra-peritoneal laparoscopic mesh repairs. Laparoscopic surgery offers benefits in terms of earlier recovery but requires an experienced surgeon to avoid complications and recurrence. The technique incurs more costs for the health service than do open methods, and the procedure takes longer. Laparoscopic repair also requires a general anaesthetic, and so is more difficult to undertake as a day case than as an open-mesh repair.
There is no evidence that the type of admission (day-case or inpatient) or the type of anaesthetic affects the outcome.
The recurrence rate may be estimated from the percentage of repairs performed for recurrent hernia. For NHS hospitals in England in 1995–96 this was 7.2%. The true recurrence rate will be much higher, as many patients do not present for further surgery. Large specialist centres quote recurrence rates of approximately 1%. The low rates seen may be due partly to short periods of follow-up and differences in case mix, but the skill of experienced hernia surgeons is also likely to be a factor.
The estimated total annual NHS cost for the treatment of hernia for a Primary Care Group (PCG) of 100, 000 patients is £160, 000.
The service may be made more cost-effective by increasing day-case surgery and reducing complications and recurrences. The latter requires that surgery is undertaken by experienced surgeons, or at least supervised by them. In part, day-case surgery is limited by the availability of adequate social care for elderly patients.
Societal costs of hernia repair would be reduced by shorter waiting times for surgery and a reduced need for recuperation after it. With modern tension-free repair methods, there is no need to limit activity following surgery.
Femoral trusses should no longer be used, as surgery is the treatment of choice for femoral hernia.
Service providers should publish recurrence rates and complication rates following groin hernia surgery.
Extending the use of laparoscopic surgery may increase waiting times for surgery, increase expenditure and result in more complications in the short term (while surgeons are on the learning curve).
A hernia (or rupture) is the protrusion of an organ through the part of the body that usually contains it. In the case of groin hernia, this is the protrusion of a part of the intestine through the abdominal wall into the groin.
The majority of patients with a groin hernia will present with a swelling in the groin, with or without discomfort, often described as a 'dragging' sensation. Where the anatomical defect is large, considerable portions of bowel may protrude from the abdominal cavity, causing an unsightly swelling and discomfort. Hernia may sometimes be confused with other causes of groin swellings, but the main problem in diagnosis is differentiating between different types of hernia or being unable to demonstrate a swelling described by a patient. Such a patient will usually present to the General Practitioner. In a smaller number of cases, a patient will present as an emergency with an incarceration and/or bowel obstruction. Prompt diagnosis and surgical admission is important in these patients. 6% of inguinal hernia repairs and 45% of femoral hernia repairs are performed as emergencies (see section 4).
Groin hernia are important because they are common and may result in discomfort and disfigurement, often interfering with the ability to work in manual jobs. There is also the risk of strangulation (where the blood supply to a section of protruding bowel becomes cut off) and intestinal obstruction (where the bowel contents are prevented from travelling through a trapped portion of intestine). The latter complications are life-threatening. Adjacent structures, such as the testis, may also be affected when the bowel becomes incarcerated or strangulated.
Groin hernia can occur at any age. They are common in babies and small children, become less common in the teens and twenties and then rise in incidence throughout the middle and later years of life.
Conventional treatments for hernia are various forms of surgery and trusses, both of which have been in use for a considerable length of time. An Egyptian papyrus (Ebers 1550 BC) described the use of bandaging (the ancient equivalent of a truss) and the use of cathartics and hot poultices for strangulation. The first description of surgery was by Celsus in AD 25.(1)
Because of the long-standing tradition of surgical repair for groin hernia, there are no randomised-controlled trials comparing surgical treatment with no treatment or indeed with a truss. There is little evidence for the effectiveness of trusses and some authors believe they cause complications, especially with prolonged use.(2),(3)
The objectives of hernia management are to relieve symptoms, to avoid deformity and to prevent complications. Successful surgery fulfils all these objectives; provided that complications are minimal, it would appear to be the ideal choice. Traditionally, trusses have been used for patients who are thought to be poor operative risks or where the risk of complications is low. Trusses may control symptoms, but there is little evidence that they can prevent complications. There is some concern that trusses may increase the risk of incarceration or strangulation, especially of the narrow-necked femoral hernia.(2) With improvements in anaesthetic technique and the advent of regional and local anaesthesia, fewer people are unfit for surgery, and so the majority of patients who would benefit from surgery may be offered it.
Hernia do not correct themselves over time and will often deteriorate, with enlargement of the hernia and increasing discomfort. Successful treatment will prevent such complications, and improvements in quality of life have been demonstrated following hernia repair.(4) It is therefore reasonable to conclude that hernia should be treated; the issue then becomes one of access to effective treatment. Inguinal hernia repair rates in England are lower than in the USA, Australia and Norway, so there is some evidence of reduced access to surgery.(2) Much of the mortality from hernia is potentially preventable, because an adequate repair prevents the complications of strangulation or obstruction. There were 311 deaths in England and Wales in 1995 attributed to inguinal or femoral hernia.(5) There is also considerable variation in mortality between countries, with England and Wales having the third highest age-standardised mortality in Europe for abdominal hernia in people aged 5–64 years.(6)
Appendix I lists the diagnostic and procedure codes.
A groin hernia is just one cause of groin swelling, but it should be possible to identify a hernia on clinical examination. Groin hernia are the commonest type of abdominal hernia. There are three distinct types of groin hernia:
Where an indirect hernia extends into the scrotum, it may be referred to as an inguino-scrotal hernia.
The anatomical deficit is different for each type.(7–10) It is important to distinguish between types because the clinical course and recommended treatment will depend on the category of groin hernia. Complications are far more frequent in femoral hernia than in either type of inguinal hernia. The distinction between direct and indirect may be made reliably only at operation. A study comparing pre-operative diagnosis of inguinal hernia with peri-operative diagnosis found that surgeons correctly diagnosed 76.9% of indirect hernia and 58.9% of direct hernia.(11)
Groin hernia may also be classified as reducible or irreducible depending on whether the abdominal contents may be returned to the abdomen manually. Irreducible hernia (where the contents may not be easily returned to the abdomen) are more likely to result in complications of strangulation and obstruction. When the hernia is small, it may often go undetected.
Data on incidence, prevalence and procedures are all presented using the anatomical categories, as this is the way in which data have been recorded. Patients may also be categorised in terms of the way they present.
There are no population-based studies that measure the incidence of groin hernia. Incidence may be measured only in terms of healthcare contacts, because many patients may be unaware of their hernia or do not seek medical attention.
Demand-incidence data for inguinal hernia have been derived from the fourth national GP morbidity survey,(13) which took place during financial year 1991/92. Sixty practices volunteered, with a total of 502 493 patients resulting in 468 042 person-years of observation. The data in Table 1 show the numbers of new and first-ever appointments in general practice for inguinal hernia. This incidence rate will underestimate the true incidence, because many people do not seek advice for their hernia and the data set may be incomplete. (Under-reporting by GPs was estimated to be about 5% for consultations but much higher for referrals to secondary care.)
Volunteer practices tended to be larger than average, with younger practice principals. There were also some socio-economic differences between the population studied and the overall population of England and Wales. For instance, ethnic minorities were under-represented in the practice populations.
Data on femoral hernia are not available from MSGP4, because data were analysed at a higher level of diagnostic code. Data have therefore been derived from the third national GP morbidity survey,(14) which took place in financial year 1981/82. Data were obtained from 48 volunteer practices, caring for 332, 270 patients and contributing 307, 803 person years to the study. These incidence data are shown in Table 2.
These estimates show femoral hernia incidence in women to be lower than in men. Femoral hernia repairs are more commonly performed in women (see section 4). Women are also more likely to require emergency repair for their femoral hernia than are men. It appears that women are less likely to present to their GPs with groin swelling and consequently are at greater risk of strangulation and emergency presentation. Alternatively, GPs may be less likely to diagnose groin hernia in women.
Using the demand-incidence rates from general practice, and the population structure of England (mid-1995 population estimates), the expected numbers of groin hernia patients in an average PCG of 100, 000 have been calculated. These are summarised in Table 3.
| Table 3: Expected numbers of groin hernia patients in a population of 100, 000 | ||
|---|---|---|
Type of hernia |
Inguinal |
Femoral |
| Male | 220 | 7 |
| Female | 27 | 9 |
| Total | 247 | 16 |
The numbers of surgical procedures performed also form an estimate of incidence, although not all patients are referred for surgical opinion and not all those assessed by a surgeon will be offered surgery. Health service activity data are summarised in section 4.
Data on prevalence rates come from the GP morbidity survey (MSGP4)(13) and from community studies.
Prevalence estimates have been derived from the morbidity survey data (see Table 4). These are available only for inguinal hernia.
| Table 4: Estimated inguinal hernia prevalence from GP morbidity studies, rates per 10, 000 person years at risk (95% CIs) | ||
|---|---|---|
Age band |
Prevalence rate in males |
Prevalence rate in females |
| 0–4 | 52 (41.5–64.4) | 7 (3.9–12.9) |
| 5–15 | 10 (6.9–14.3) | 2 (0.92–4.5) |
| 16–24 | 14 (10.3–19.2) | 2 (0.8–4.4) |
| 25–44 | 25 (21.6–29.1) | 3 (1.9–4.6) |
| 45–64 | 83 (74.8–91.2) | 7 (4.9–9.8) |
| 65–74 | 156 (139–175) | 10 (6.2–15.9) |
| 75–84 | 262 (234–293) | 18 (11.8–28.4) |
| 85 and over | 267 (206–343) | 35 (15.6–63.5) |
| Source: MSGP4(13) | ||
There have been no comprehensive prevalence studies of groin hernia in the wider community. The most comprehensive reference is a paper by Abramson et al.(12) They undertook a community survey of men in western Jerusalem using a combination of interview and clinical examination. The prevalence of unrepaired inguinal hernia was recorded, as well as any history of hernia repair. The results of their survey are summarised in Table 5.
| Table 5: Prevalence of inguinal hernia by age group | |||||||
|---|---|---|---|---|---|---|---|
Age group examined (years) |
25–34 |
35–44 |
45–54 |
55–64 |
65–74 |
75 plus |
Total |
| No. of men examined | 620 | 438 | 300 | 322 | 156 | 47 | 1883 |
| Current prevalence (excluding successful repairs) | 11.9% | 15.1% | 19.7% | 26.1% | 29.5% | 34.1% | 18.3% |
| Lifetime prevalence (including successful repairs) | 15.2% | 19.4% | 28.0% | 34.5% | 39.7% | 46.8% | 24.3% |
| Source: Abramson et al.(12) | |||||||
To ensure consistency of diagnosis, all the examining doctors were trained in the examination and clinical diagnosis of inguinal hernia using the method described by Bailey.(15) While consistency is assured, however, the data will not be entirely accurate, as clinical diagnosis is not always confirmed at surgery.(11) A cough impulse at a scar site was taken as a recurrence. Response rates from those aged under 25 years were low and so the analysis was confined to men aged over 24 years. The poor response rate in the younger group was thought to be a result of service in the armed forces. The response rate for interviews in the 25-plus group was 86%, 91% of whom participated in the follow-up examination.
This study shows an increasing prevalence of inguinal hernia with increasing age in adult males. Hernia were more common on the right in a ratio of 1.3 to 1. One in every five of all hernia showed evidence of recurrence. Only 54% of men with an unoperated swelling reported having a hernia. It is not known how well these results translate to the UK population.
Abramson et al. also summarised comparative studies on hernia prevalence from other countries. The results of their study were comparable with those from the other studies and so are likely to be a reasonable estimate. They show that the prevalence estimates from the GP morbidity survey(13) are gross underestimates, even assuming that only half of those with a hernia are aware of it.
Prevalence estimates from other studies are summarised in Table 6, adapted from Abramson et al.
| Table 6: Prevalence estimates of types of abdominal hernia | ||
|---|---|---|
Study |
Population |
Prevalence rate of hernia |
| Cohen J and Efran Male, 1964 | Israel. Males aged 17–18 in the cohort born in 1940. Inguinal hernia. | 0.8% |
| Zimmerman LM, Anson BJ, 1967(16) | USA. First million drafted in World War I. All hernia. | 2.0% |
| Ditto | USA. Selective service registrants. 3 million from World War II. All hernia. | 8.0% |
| Nilsson JR, 1937(17) | USA. Routine examination of 7967 railroad workers. All hernia, including operated. | 9.5% |
| Trussell RE, Elinson J, 1959(18) | USA, New Jersey. All abdominal hernia; probability sample of 277 men aged 25 and over. | 5.3% (25–44 years) 6.0% (45–64 years) 22.9% (65 plus) |
| Zimmerman LM, Anson BJ, 1967(16) | UK. Recruits in World War I. | 0.6%–12.5%, depending on age |
| Edwards H, 1943(19) | UK. Recruits in World War II. Abdominal hernia; 1300 men aged 35–36 years. | 11.0% |
| Yordanov YS, Stoyanov SK, 1969(20) | Pemba (an island close to Zanzibar). Hospital patients or relatives of patients not attending with hernia. Inguinal hernia in 528 men aged over 21 years. | 25.2% |
Several African studies have demonstrated a prevalence in adult males of between 7.7% and 25.2%.(21) It is not possible to comment on possible ethnic differences in hernia prevalence, because studies have used non-comparable samples.
Akin et al. studied a series of 27, 400 army recruits aged between 20 and 22 years in Turkey in 1995.(22) An inguinal hernia was found in 3.2% of men, with 54.1% being right-sided, 39.7% left-sided and 6.2% bilateral.
Using the hospital-episode data for England for financial year 1995/96, the ratio of primary inguinal hernia repairs to primary femoral repairs was 16.4:1. Although hernia repairs were much more common in men than in women (ratio 7.6:1), femoral hernia repairs were more common in women than in men. The ratio of primary inguinal hernia repair to primary femoral hernia repair is 50:1 in men and 1.9:1 in women. These figures do not reflect the total incidence of groin hernia, as there will be patients who do not present, patients who are not referred from general practice and patients who are not offered or who refuse surgery.
Barwell described a series of over 4000 groin hernia repairs.(21) In these, the ratio of indirect to direct inguinal repairs was 8.3:1 in women and 2.4:1 in men.
Estimates of the risks of strangulation vary enormously, but many of them seem to be based on hearsay rather than on fact. Gallegos(23) studied 476 hernia repairs in a UK hospital population and used Kaplan–Meier survival analysis to estimate the cumulative probability of strangulation over the length of the clinical history. For inguinal hernia, the cumulative probability of strangulation was 2.8% at 3 months, 4.5% after 2 years and 8.6% after 5 years (i.e. an estimated annual strangulation risk of 1.7%). For femoral hernia, the cumulative probability of strangulation was 22% at 3 months and 45% at 21 months. They demonstrated that the cumulative risk of strangulation increased at the greatest rate in the first three months of the history. They also found that patients who were admitted with a strangulated hernia had much shorter clinical histories than those on the waiting list. This suggests that hernia at risk of strangulation may strangulate before patients are referred to hospital.
McEntee et al.(24) undertook a retrospective study of 79 patients who presented with clinical evidence of strangulation between 1979 and 1987. 46 (58%) had noticed a hernia for at least one month prior to strangulation. Of these, 39% had not reported the hernia to their GP, 41% had reported the hernia to a doctor but had not been referred for surgical opinion and 20% had been assessed surgically with a view to elective repair. 40% of patients had presented within days of developing a hernia. In a smaller study by Allen et al., 18 of 25 patients with strangulated hernia had known of their hernia for over a year before the emergency admission.(25)
Neuhauser made two estimates of the annual risk of strangulation.(26) The first was based on a series of 8633 patients with inguinal hernia described by Berger(27) in 1895 and gave a probability of strangulation or obstruction of 0.4% per annum. Berger questioned patients who came to see him for the fitting of a truss, asking them the length of history and whether they had had any episodes of obstruction or incarceration. Neuhauser states that Berger's data showed a mortality from incarceration of 8.5%, and therefore increased the rate of strangulation or incarceration by 10% to account for this. It is not at all clear how Berger could have demonstrated a mortality rate from strangulation when he studied live patients.
The second source of data used was an unpublished study in Columbia where almost no routine hernia operations were performed. The numbers of operations on strangulations or incarceration were related to the population at risk. The yearly probability of strangulation was 0.3%. There are several problems with this estimate. It assumes that anyone in the designated population with incarceration or strangulation would have been admitted to hospital and operated on. The data also assume that it was possible to identify accurately a population at risk. The epidemiology of groin hernia appears to vary in different ethnic populations, so the results of studies in Columbia may not be applicable to a European population.(28),(29)
Mortality from groin hernia may occur from the complications of groin hernia (usually strangulation or incarceration) or from the complications of surgery. The mortality rate is much higher following emergency surgery than after elective surgery. Mortality following either emergency or elective surgery has fallen over the years.
Charlton et al.(30) demonstrated huge differences in mortality from abdominal hernia between health authorities for the years 1974–78. These differences were still present even when accounting for differences in population structure and differing levels of deprivation. It seems likely that such inequalities still exist today. These differences may reflect the quality and accessibility of services provided. However, the data refer to all types of abdominal hernia, and it is difficult to be sure that these inequalities would still be present if groin hernia were looked at in isolation.
The largest series of strangulated hernia was described by Frankau in 1931.(31) He studied 1487 strangulated abdominal hernia from a number of hospitals in Britain and Ireland. Mortality rates from strangulation were 12.6% for inguinal hernia and 12.9% for femoral.
Reaveley et al.(6) studied deaths from abdominal hernia in Nottingham over a six-year period. The majority had presented with symptoms of incarceration or strangulation. Of the 20 deaths from inguinal hernia, only half had had a history of the hernia documented in GP records.
Based on 1995/96 HES data, approximately 8% of operations are performed as emergencies. The indication for emergency surgery would be complications, so this figure of 8% gives an estimate of the lifetime risk of strangulation or incarceration. This risk estimate applies to current surgical practice, so complication rates would be much higher if no repairs were done as routine.
For calendar year 1995 in England and Wales, there were 721 deaths where abdominal hernia was given as the underlying cause. Inguinal hernia caused 183 deaths and femoral hernia 128. 75.4% of the inguinal hernia deaths and 85.2% of the femoral hernia deaths were in people aged 75 years and over.
In 1995/96, there were 256 deaths in hospital following groin hernia surgery. The numbers of deaths by operation type and admission method are summarised in Table 7. Deaths are more common following emergency surgery than following elective surgery. Death is more common following femoral hernia surgery than following inguinal surgery.
Overall mortality rates following groin hernia repairs are in Table 8.
Trends in groin hernia deaths following surgery are demonstrated in Figure 1. These are the numbers of admissions for groin hernia repair where the discharge method was death – i.e. they do not include any deaths that occurred following discharge from hospital.
| Figure 1: Trends in deaths following groin hernia surgery between 1989/90 and 1995/96 |
|---|
|
| Source: HES data, 1989/90–1995/96 |
The investigation and management of groin hernia is usually straightforward. Patients are not routinely screened for hernia, although one may be detected as part of a physical examination. Small hernia may go unnoticed even by the patient, and patients with symptoms or signs do not all present to the GP.
A patient with groin hernia has three choices: no treatment, a truss or surgical repair. PCGs need to develop clear guidelines for referral and management in partnership with surgical colleagues.
This has been advocated for small, direct hernia in the elderly and for people regarded as too infirm to withstand surgery. Patient selection on clinical criteria is likely to fail, because the differentiation between direct and indirect inguinal hernia can be made with certainty only at operation.(11) A policy that legitimises patient selection may explain the large numbers of patients whose family doctors do not refer for surgical opinion.
Although there remains a perception amongst patients and some doctors that a truss can be used to manage an inguinal hernia, there is no evidence base to support the truss as a definitive treatment.(2) However, a truss may be used to alleviate symptoms in a patient awaiting surgery. In 1991, an estimated 40, 000 trusses were provided annually in the UK.(32) For the 12-month period December 1998 to November 1999, 16, 000 trusses were prescribed in England, 32 of them for femoral hernia.[a]
Surgery is of two types: traditional open surgery or laparoscopic repair. A laparoscopic repair is either totally extra-peritoneal (TEP) or transabdominal preperitoneal (TAPP). The latter repair involves entering the peritoneal cavity, and is being superseded by the TEP approach. The commonest repair uses a mesh prosthesis stapled over the hernial orifice and then covered by peritoneum to prevent local adherence to the bowel.
In open surgery an incision is made in the inguinal region, with exposure of the hernia. The sac is excised or reduced. In all but infant hernia procedures, the posterior wall of the inguinal canal is repaired or reinforced, with support and narrowing of the internal inguinal ring. These features are common to all open repairs. The procedure can be carried out under general or local anaesthesia if the hernia is reducible and the patient is not obese.
The precise nature of the surgical repair depends on the operator's preference. Essentially there are two choices:
It is important to note that most surgeons use a modification of an originally described method, which may have evolved considerably by passage through the hands of several surgeons.
There are three main methods of femoral hernia repair:
Laparoscopic methods and mesh may also be used.
Data on service provision in this report are based on hospital-episode data from NHS hospitals in England (HES data). The data have been analysed on the basis of admissions rather than finished consultant episodes (FCEs). Data have been extracted on the basis of procedure codes (OPCS4 – see Appendix I). The procedure rates and any trends in service provision in the NHS need to be considered in the light of private healthcare provision over the same time period.
In the financial year 1995/96, there were 87, 651 inguinal hernia repairs in NHS hospitals in England. Of these, 81, 323 (92.8%) were primary repairs and 6328 (7.2%) recurrent repairs. These represent a crude repair rate (per 100, 000) of 180, a crude primary repair rate of 167 and a crude recurrent repair rate of 13.0. 91% of operations were recorded as on men and 7.6% on women, while in 1.6% of admissions the gender was unclassified. There has been a steady increase in the numbers of operations performed annually since the late 1980s. This contrasts with the previous 15 years, when numbers had on average remained static.(21) Between 1989/90 and 1995/96, inguinal hernia repairs rose by 27% in men and 5% in women. It is not clear why there is this gender disparity.
In 1995/96, 89.5% of inguinal hernia repairs were performed as a single procedure (i.e. no additional procedures were performed at the same time). This compares with 83% in 1989/90. This change may have arisen as a result of the increase in day-case surgery – combined procedures are not suitable for day-case repair. Alternatively, it could be an artefact of the coding or of the data analysis.
Applying incidence rates in general practice to the population in England, there would be an estimated 120, 314 new cases of inguinal hernia per annum in England presenting to general practitioners (107, 258 men and 13, 056 women). For the year 1995/96, there were only 87, 651 hernia repairs, which suggests that only 73% of those presenting to GPs have an operation.
In the financial year 1995/96, there were 5146 femoral hernia repairs in NHS hospitals in England. Of these, 4951 (96.2%) were primary repairs and 195 (3.8%) recurrent repairs. These represent an overall crude repair rate (per 100, 000) of 10.6, a crude primary repair rate of 10.2 and a crude recurrent repair rate of 0.4. The number of femoral hernia repairs performed annually remained steady between 1989/90 and 1995/96, a pattern similar to that seen in the previous 15 years.(21)
Applying incidence rates in general practice to the population in England, there would be an estimated 8012 new cases of femoral hernia per annum in England presenting to general practitioners (3470 men and 4540 women). For the year 1995/96, there were only 5146 hernia repairs, which suggests that only 64% of those presenting to GPs have an operation.
In 1995/96, 83.5% of femoral hernia repairs were performed as a single procedure, compared with 72.5% in 1989/90. Only 31.8% of recurrent femoral repairs were performed as single procedures. The apparent increase in single procedures may have arisen as a result of the increase in day-case surgery – as we remarked earlier, combined procedures are not suitable for day-case repair. Alternatively, it could be an artefact resulting from different methods of analysing the HES data or from the effect of changes in coding practice.
Rates have been calculated using the ONS mid-1995 population estimates for England. Some of the rates are derived from very small actual numbers, so the confidence intervals on these would be wide.
The procedure rates for inguinal hernia are summarised in Table 9.
| Table 9: Rates of inguinal hernia repair by age and gender[b] | ||||||||
|---|---|---|---|---|---|---|---|---|
Age band in years |
Primary repairs |
Recurrent repairs |
||||||
No. of repairs |
Rate per 10, 000 population |
No. of repairs |
Rate per 10, 000 population |
|||||
Male |
Female |
Male |
Female |
Male |
Female |
Male |
Female |
|
| 0–4 | 8606 | 856 | 51.9 | 5.4 | 54 | 5 | 0.3 | 0.03 |
| 5–14 | 3916 | 732 | 12.3 | 2.4 | 57 | 5 | 0.2 | 0.02 |
| 15–24 | 2728 | 155 | 8.5 | 0.5 | 69 | 5 | 0.2 | 0.02 |
| 25–44 | 10, 610 | 854 | 14.5 | 1.2 | 490 | 27 | 0.7 | 0.04 |
| 45–64 | 23, 084 | 1378 | 42.5 | 2.5 | 2077 | 60 | 3.8 | 0.11 |
| 65–74 | 14, 473 | 1041 | 73.2 | 4.4 | 1866 | 33 | 9.4 | 0.14 |
| 75–84 | 8608 | 1077 | 93.0 | 6.9 | 1230 | 37 | 13.3 | 0.24 |
| 85 plus | 1529 | 340 | 70.8 | 5.2 | 210 | 14 | 9.7 | 0.22 |
| All ages | 73, 554 | 6433 | 30.8 | 2.6 | 6053 | 186 | 2.5 | 0.07 |
Age- and sex-specific rates of primary and recurrent hernia repair are shown in Figures 2 and 3.
| Figure 2: Age- and sex-specific primary inguinal hernia repair rates |
|---|
 |
| Source: HES data 1995/96 |
| Figure 3: Age- and sex-specific recurrent hernia repair rates |
|---|
 |
| Source: HES data 1995/96 |
Inguinal hernia repairs are much more common in men than in women at all ages. The age-specific rates are high in infants and in the elderly. 91% of procedures were recorded as performed on men and 7.6% on women, while in 1.6% of procedures the gender was unclassified.
In 1995/96, 68.1% of femoral hernia repairs were recorded as performed on women and 31.0% on men, while in 0.9% of admissions the gender was not classified.
Age- and gender-specific rates of femoral hernia repair are presented in Table 10. Many of the rates are calculated from small actual numbers, so the confidence limits on the rates would be wide. Femoral hernia repairs are more common in women than in men.
| Table 10: Rates of femoral hernia repair by age and gender, England 1995/96[c] | ||||||||
|---|---|---|---|---|---|---|---|---|
Age band (years) |
Primary repairs |
Recurrent repairs |
||||||
No. of repairs |
Rate per 10, 000 population |
No. of repairs |
Rate per 10, 000 population |
|||||
Male |
Female |
Male |
Female |
Male |
Female |
Male |
Female |
|
| 0–4 | 10 | 8 | 0.6 | 0.5 | 1 | 1 | 0.1 | 0.1 |
| 5–14 | 28 | 25 | 0.9 | 0.8 | 3 | 2 | 0.1 | 0.1 |
| 15–24 | 20 | 32 | 0.6 | 1.1 | 0 | 1 | 0.0 | 0.0 |
| 25–44 | 105 | 434 | 1.4 | 6.1 | 6 | 13 | 0.1 | 0.2 |
| 45–64 | 426 | 765 | 7.9 | 13.9 | 22 | 29 | 0.4 | 0.5 |
| 65–74 | 395 | 756 | 20.0 | 31.8 | 25 | 29 | 1.3 | 1.2 |
| 75–84 | 369 | 887 | 39.9 | 57.0 | 20 | 23 | 2.2 | 1.5 |
| 85 plus | 118 | 501 | 54.6 | 77.3 | 2 | 17 | 0.9 | 2.6 |
| All ages | 1471 | 3408 | 6.2 | 13.7 | 79 | 115 | 0.3 | 0.5 |
| Source: HES data 1995/96 | ||||||||
Age- and gender-specific primary and recurrent femoral hernia repair rates are demonstrated in Figures 4 and 5.
| Figure 4: Age- and gender-specific primary femoral hernia repair rates |
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| Source: HES data 1995/96 |
| Figure 5: Age- and gender-specific recurrent femoral hernia repair rates |
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| Source: HES data 1995/96 |
There has been a steady increase in the percentage of operations performed as day cases over the seven-year period examined. This trend is seen in all three types of procedure, but day-case surgery is much more common in primary repair than in recurrent repair. These trends are demonstrated in Figure 6.
| Figure 6:Trends in percentage of inguinal hernia repairs performed as day cases, by procedure type |
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 |
| Source: HES data 1989/90–1995/96 |
For the financial year 1995/96, 29.7% of all inguinal hernia repairs were performed as day cases. Of the 81, 126 elective inguinal hernia repairs, 32.1% of were done as day cases. 65.5% of elective repairs were performed in people under 65 years and 86.0% were performed in people under 75 years. If all elective surgery in those under 65 years were done as day cases, there would be a 104% rise in day-case surgery numbers. If all elective surgery in those under 75 years were done as day cases, there would be a 168% rise in day-case surgery numbers.
The percentage of operations performed as day cases falls with increasing age (Figure 7).
| Figure 7: Percentage of inguinal hernia procedures performed as day cases, by age |
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| Source: HES data 1989/90–1995/96 |
While it is understandable that elderly patients are admitted to hospital for their hernia repairs, it seems surprising that less than half of people in their twenties and thirties are operated on as day cases. Some patients may have had associated procedures that necessitated admission and some will have been admitted as emergencies, but these are unlikely to account for more than about 10%.
Despite the growth in day-case surgery, there remains potential for further expansion. Patients who are not felt suitable for day-case hernia repair are usually those who do not have adequate support at home or who are particularly frail. This usually affects the elderly. Some day-case units operate an age-based policy, generally offering day-case surgery to younger patients only. Units in the West Midlands have quoted cut-off ages of 65 to 75 years. Specialist independently-funded hernia centres usually do all of their surgery on a day-care basis,(35),(36) but it may be that they do not have any frail, elderly customers without social support. Some of the specialist centres only undertake surgery that uses local anaesthesia.
Tables 11 and 12 show the numbers of admissions by age and gender for day-case surgery and for ordinary admissions.
As with inguinal hernia, the percentage of operations performed as day cases has increased (Figure 8), although femoral hernia operations are much less likely to be performed as day cases than are inguinal hernia, in part because a much higher percentage of operations are done as emergencies. Recurrent repairs are less likely to be performed as day cases than are primary repairs. Day-case surgery becomes less common with increasing age (Figure 9).
In the financial year 1995/96, 12.1% of primary repairs and 8.2% of recurrent repairs were performed as day cases. For primary and recurrent repairs combined, 11.9% of procedures were performed as day cases. In the same year, there were 2807 elective femoral hernia repairs. Of these, only 613 (21.8%) were done as day cases. 52.1% of elective repairs were in people aged under 65 years and 76.2% in people aged under 75 years. If all elective surgery in those under 65 years were done as day cases, there would be a 139% rise in day-case surgery. If all surgery in those under 75 years were done as day cases, there would be a 249% rise in day-case surgery.
| Figure 8: Trends in the percentage of admissions for femoral hernia classified as day cases |
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| Source: HES data 1995/96 |
| Figure 9: Percentage of femoral hernia operations performed as day cases, by age |
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| Source: HES data 1995/96 |
The numbers of procedures performed as day cases and as ordinary admissions, by age and gender, are set out in Tables 13 and 14.
Length of stay for those admitted has fallen gradually over the last 7 years. These trends are demonstrated in Figures 10 and 11. For some procedures the median length of stay was 0 because of the large numbers done as day cases.
| Figure 10: Trend in mean length of stay for inguinal hernia repair |
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 |
| Source: HES data 1989/90–1995/96 |
| Figure 11: Trend in median length of stay for inguinal hernia repair |
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 |
| Source: HES data 1989/90–1995/96 |
The average length of stay is affected by the increasing numbers of day cases. Table 15 shows the average length of stay for ordinary admissions for 1995/96.
Length of stay for femoral hernia repair has fallen steadily (Figures 12 and 13). The median length of stay for primary and recurrent repair was 2 days in 1995/96. The mean length of stay was 4.2 days for primary repair and 3.2 days for recurrent repair.
| Figure 12: Trends in mean length of stay for femoral hernia repair |
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| Source: HES data 1989/90–1995/96 |
| Figure 13: Trends in median length of stay for femoral hernia repair |
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| Source: HES data 1989/90–1995/96 |
When day cases are excluded, the length of stay is longer. The average lengths of stay for 1995/96 are summarised in Table 16.
The length of stay for primary repair is longer than for recurrent repair. This is presumably because a higher number of primary repairs are performed as emergencies.
Hernia recurrence was included in the high-level performance indicators published by the NHS Executive in June 1999. These are published as a directly age-standardised rate: recurrent repair per 100, 000 population per annum, based on HES data 1997–98. The rate for England was 11, with rates for health authorities ranging from 2 to 17. These figures are difficult to interpret, relating as they do to several types of hernia. Low rates may reflect a reluctance to undertake repair of recurrent hernia, rather than relating to the success of primary repairs.
An approximation of the recurrence rate in England under current practices may be obtained from the percentage of procedures that are for recurrent hernia – in 1995/96, 7.2%.
There has been a steady rise in the percentage of repairs performed for recurrent hernia from the 5.2% seen in 1989/90. It is possible that this represents an increase in the failure rate, but it is perhaps more likely to be a reflection of a greater willingness to operate on recurrent hernia. Whatever the reasons for the rise, it suggests that in routine NHS practice the recurrence rate is nearer to 10% than to the 1% quoted by specialist centres.
In 1995/96, 3.8% of femoral hernia repairs were for recurrence. There has been a gradual reduction in the proportion of procedures for recurrence from the 5.7% seen in 1989/90.
The percentage of admissions for inguinal hernia that are classified as emergencies has fallen from 9.1% in 1989/90 to 6.0% in 1995/96. This trend is statistically significant (p<0.0001 using the chi-squared test for trend). In 1995/96, 6.0% of admissions were classified as emergencies. 5.9% of primary repairs and 7.4% of recurrent repairs were classified as emergency admissions. One of the main objectives in undertaking hernia repair is to prevent obstruction and strangulation. This should lead to a fall in emergency admissions. Numbers of admissions by admission method are summarised in Table 17.
There has been a small fall in the percentage of admissions classified as emergencies, from 47.4% in 1989/90 to 43.7% in 1995/96. This trend is statistically significant (p<0.0001 using the chi-squared test for trend). 44.8% of the primary repairs and 23.6% of the recurrent repairs were done as emergencies. In Scottish Health Boards, 47.9% of femoral hernia repairs were done as emergencies.(37) The numbers of admissions by admission method are summarised in Table 18.
A woman is more likely to be admitted as an emergency for a femoral hernia repair than is a man. This may be because women are less likely to present to their GPs with groin swellings, are less likely to be referred for surgery or have to wait longer than men, or because femoral hernia in women is more likely to incarcerate or strangulate. There is some supporting evidence for the first of these explanations from the demand-incidence data in general practice (see section 4).
The length of wait has increased steadily over the seven-year period examined (Figure 14). For inguinal hernia repairs in England in 1995/96, there was a mean wait of 133 days and a median wait of 85 days. For people unable to work as a consequence of their hernia, this length of wait is unacceptable. The median wait in Scotland for inguinal hernia for 1993 was somewhat less, at 56 days.(37)
| Figure 14: Trends in median length of wait for inguinal hernia repairs |
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| Source: HES data, 1989/90–1995/96 |
There are marked variations in waiting times between different health authorities (Figures 15, 16 and 17), with a two-fold difference between the best and the worst.
| Figure 15: Regional variation in waiting times for excision of the hernial sac |
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| Source: HES data 1995/96 |
| Figure 16: Regional variation in waiting times for primary inguinal hernia repair |
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| Source: HES data 1995/96 |
| Figure 17: Regional variation in waiting times for recurrent inguinal hernia repair |
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| Source: HES data 1995/96 |
Waiting times for femoral hernia have also risen steadily over the 7-year period examined (Figure 18). This, combined with the static numbers of operations being performed (see 'Volume of surgery' in section 4), suggests that the referral rate for surgery has increased. For the financial year 1995/96, the median wait for femoral hernia repair was 47 days, with a mean wait of 91.5 days. In Scotland in 1993, the median wait was 40 days.(37)
| Figure 18: Trends in median length of wait for femoral hernia repair |
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| Source: HES data, 1989/90–1995/96 |
Marked variations in waiting times are observed between different regional health authorities (Figures 19 and 20), with as much as a six-fold difference between the best and the worst.
| Figure 19: Regional variation in waiting times for primary femoral hernia repair |
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| Source: HES data 1995/96 |
| Figure 20: Regional variation in waiting times for recurrent femoral hernia repair |
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| Source: HES data 1995/96 |
Data on privately funded procedures are not widely available. However, the Medical Care Research Unit at Sheffield University surveyed independent hospitals in England and Wales in three separate years.(38),(39) The 1992/93 survey was sent to 217 independent hospitals in England and Wales, 93% of whom replied. The Unit used the results to estimate the numbers of procedures carried out. The results for abdominal hernia are summarised in Table 19.
For the financial year 1992/93, abdominal hernia repairs comprised 2.4% of the private procedure workload. The majority of abdominal hernia repairs are likely to be for groin hernia. There was an increase of 65% in abdominal hernia repairs between 1981 and 1986 and an increase of only 5% between 1986 and 1992/3. This contrasts with an overall increase in the number of private operations of 67% between 1981 and 1986 and 42% between 1986 and 1992/93. Using incidence data on abdominal hernia from the GP morbidity survey GPMS3,(14) 49% of abdominal hernia presenting in general practice were groin hernia. Allowing for this and correcting for the fact that the independent hospital data relate to England and Wales, we would expect 7606 privately funded operations in the UK per year. This is equivalent to 15.5 per PCG of 100, 000. In the GP morbidity survey,(14) 5.6% of outpatient referrals for abdominal hernia were to the private sector. Applying this to the number of expected new cases of groin hernia (263 – see section 4), we would expect 14.7 referrals per PCG of 100, 000. These two estimates, calculated in different ways, are very close, which helps to validate the estimate.
Unfortunately, there are no data more recent than 1992/93 concerning levels of service provision in the private sector. There has been an underlying trend of increasing activity in the private sector, and a recently established specialised hernia repair centre (the British Hernia Centre) appears to be flourishing. They have reported results on thousands of patients.(40) This, along with increasing waiting times in the NHS and anecdotal reports of employers who are willing to pay for procedures for their own staff to avoid long periods of sick pay, suggests that numbers will have continued to rise. From the limited data available, it appears that there has been a greater percentage increase in the number of operations in the private sector than in the NHS, so that private patients may well be referred more frequently than the 5% seen in 1981/82.
The costs involved in the treatment of groin hernia are presented in Table 20. Some of these are charges (e.g. ECR charges) and as such will not necessarily be an estimate of the true cost. The actual price paid by a purchaser will often be lower when the service is included in a block contract.
| Table 20: Costs and sources for groin hernia services | ||
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Item |
Unit cost |
Source of cost data |
| Private day-case surgery. Price includes assessment and follow-up | £895 | Informal enquiry to the London Hernia Centre in 1998 for a simple inguinal hernia repair in a fit 45-year-old man |
| Private GP consultation | £36 | Medi Centre charge for consultation lasting up to 15 minutes. September 1998 |
| Inpatient groin hernia repair | £814 | HRG H73 / H74 (inguinal or femoral hernia repair in a patient aged under 70 years without complications). Average ECR cost for West Midlands trusts, 1998/99 |
| Day-case groin hernia repair | £488 | HRG H73 / H74 (inguinal or femoral hernia repair in a patient aged under 70 years without complications). Average ECR cost for West Midlands trusts, 1998/99 |
| Outpatient appointment, first visit | £73 | Average ECR cost for West Midlands trusts, 1998/99 |
| Outpatient appointment, follow-up | £41 | Average ECR cost for West Midlands trusts, 1998/99 |
| General practitioner consultation | £14 |
Estimates from PSSRU at the University of Kent, based on 1996/97 prices(41) |
| Practice nurse consultation | £6 | |
| Practice nurse procedure | £6 | |
| Truss prescription | £16 | Prescription Pricing Authority data for 1997/98. Mean cost of groin truss |
These models are derived from data on existing service provision and not on a desired model of care. The model has been kept as simple as possible. It does not include the option of referral and conservative treatment, because there are no data on which to estimate likely numbers for this scenario. In practice, those who are prescribed trusses will require repeat prescriptions and assessments over the years. Data on truss use were based on numbers of prescriptions rather than on numbers of patients, so this will account for the annual expenditure on truss assessments and prescriptions. The majority of expenditure is on surgery.
For a PCG of 100, 000 patients, in each year there would be 247 new referrals with inguinal hernia and 16 referrals with femoral hernia. Of the 247 inguinal hernia, 14 would be referred to the private sector, 180 would be operated on in the NHS and 53 would be treated conservatively. Of the NHS operations, 53 would be done as day cases and 127 as inpatient procedures. Of the 16 femoral hernia repairs, 5 would be treated conservatively, 1 would be referred to the private sector and 10 would be operated on in the NHS. Of the NHS operations, 1 would be done as a day case and 9 would be done as inpatient procedures. (See flowchart)
| Figure 21: Inguinal hernia: modelling patient flows |
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| Figure 22: Femoral hernia; modelling patient flows[d] |
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15 episodes each requiring one GP appointment and one practice-nurse
appointment.
Total £300
136 episodes each requiring two GP appointments, one new outpatient
appointment, one surgical inpatient procedure and one practice-nurse
appointment.
Total £125, 256
54 episodes each requiring two GP appointments, one new outpatient
appointment, one surgical day-case procedure and two practice-nurse
appointments.
Total £32, 454
58 episodes each requiring two GP appointments. 32 episodes requiring truss
prescription.
Total £2136
The estimated total annual NHS costs of treatment for hernia for a PCG of 100, 000 patients is £160, 000.
The aims of hernia treatment are threefold:
There is no trial that compares surgery for groin hernia with no treatment or with conservative treatment (i.e. trusses). Research is dominated by outcome studies of inguinal hernia repair, by measurement of recurrence rates and by trials comparing different methods of inguinal hernia repair. Corresponding data for femoral hernia are sparse.
There is a consensus among surgeons that surgery is the treatment of choice in children and in patients with femoral hernia. This is because the lifetime risk of obstruction or strangulation is higher in these two groups of patients. The Royal College guidelines published in 1992 advised that a small direct hernia in an elderly person might be best left untreated.(42) However, the distinction between a direct and an indirect hernia is not easily made clinically, with an accuracy of only 69%.(25)
The effectiveness of surgery is usually measured in terms of recurrence rate, recovery period or return to work, and complications. Unfortunately there is no standard definition of a 'recurrence'. The reported recurrence rate in any series may depend on the procedure used, the skill of the operator, the length of follow-up and the method of identifying recurrences – e.g. regular review by a clinician versus self-reporting. There are few studies that look at quality of life before and after surgery.
Surgery is certainly effective in that it offers a cure for the anatomical defect in most people. Evaluation of the quality of life before and after hernia surgery has also demonstrated significant reduction in pain and improvement in function.(4)
Reported recurrence rates for groin hernia repair vary enormously.(43) There has been a general trend for recurrence rates to fall over time, and specialist centres publish very low recurrence rates. The British Hernia Centre claims a recurrence rate of less than 1% over follow-up of one-and-a-half to five years.(40),(44) The Shouldice Centre and the Lichtenstein Centre quote similarly low recurrence rates.(33),(45) This is probably due in part to the skill and expertise of the dedicated hernia surgeons, but there are also some claims that it is a result of their chosen method.(33) Other series quote recurrence rates for inguinal hernia repair of between 0.7% and 14.3%.(21) Failure of recurrent inguinal hernia repair may be as high as 30%.(46)
In his review of 2105 femoral hernia repairs, Glassow found recurrence rates of 2% for primary repairs and 7–10% for recurrent repairs.(47) A Spanish series of 93 femoral hernia repairs (using the Lichtenstein technique), with follow-up ranging from 2 to 4 years, reports 1 recurrence in 93 repairs (recurrence rate 1.1%).(48)
Scottish Health Boards report a recurrence rate of 1% for inguinal hernia and 0.5% for femoral hernia over a 2-year follow-up period,(37) but it is not clear how recurrence has been defined. If the figures have been derived from routine data sources, they are likely to be an underestimate.
In the USA, approximately 10% of all hernia repairs are for recurrent hernia.(49) The equivalent figure for England, using 1995/96 HES data, is 7.2%. These figures will under-estimate the true recurrence rate, as they are dependent on the diagnosis and on referral for recurrent repair.
Differences in case mix are unlikely to account for the large differences in outcome between these overall rates and those quoted by specialist centres. The average age of men operated on at the British Hernia Centre is lower than for those operated on in the NHS. However, the British Hernia Centre does operate on elderly patients and on patients with a variety of manual and sedentary occupations.(40) They are also hap