European Journal of Cardiovascular Medicine

Inguinal hernia is among the commonest conditions encountered in general surgical practice, with an estimated lifetime risk of about 27% in men and 3% in women.[1] Hernia repair is one of the most frequently performed operations worldwide, and several hundred thousand groin hernia repairs are carried out every year in the United States alone.[2] In India, a large proportion of the population is engaged in heavy manual labour, awareness of the need for elective repair is limited and access to surgical care is uneven. Consequently, many inguinal hernias remain unrepaired for years and patients often present to a hospital only when a complication has developed.[3,4]

An inguinal hernia may be reducible, irreducible (incarcerated), obstructed or strangulated. In an obstructed hernia the lumen of the herniated bowel is occluded but its blood supply remains intact, whereas in a strangulated hernia the blood supply of the contents is compromised, so that ischaemia, gangrene and perforation follow if the constriction is not relieved promptly.[5] Although the overall risk of strangulation in a given patient with an uncomplicated inguinal hernia is low, it is cumulative and highest in the first months after the hernia appears, being estimated at about 2.8% at three months and 4.5% at two years in one classic study.[6] An Indian study from a tertiary centre in southern India has likewise examined the risk of obstruction and strangulation in groin hernias and the factors that determine it.[7]

The role of elective repair in minimally symptomatic hernias has been debated. A randomised trial of watchful waiting versus repair in minimally symptomatic men reported a very low rate of acute incarceration, about 1.8 per 1000 patient-years, and no difference in short-term outcomes.[8] With longer follow-up, however, about two-thirds of the men assigned to watchful waiting eventually crossed over to surgery, mostly because of increasing pain, and a rising proportion required repair under emergency conditions in older age groups.[9] A systematic review reached similar conclusions, namely that watchful waiting is safe for selected asymptomatic patients but that most will eventually need repair.[10] These results cannot be extrapolated directly to patients in low-resource settings, where follow-up is irregular and the interval between the onset of obstruction and arrival at a surgical facility may be several days.

Emergency surgery for an obstructed or strangulated hernia carries a considerably higher risk than elective repair. Population-based studies from the United Kingdom, Sweden and Denmark have shown that mortality after emergency groin hernia repair is several times higher than after elective repair and that the excess is concentrated among elderly patients and those needing bowel resection.[11-13] Emergency repairs still constitute a significant fraction of all hernia operations, and in the United States the burden of emergent hernia repair has been rising with an ageing population.[14,15] In sub-Saharan Africa and other low- and middle-income regions, where strangulated hernia remains a leading cause of emergency abdominal surgery, morbidity and mortality are higher still.[16]

Several issues remain contested in the surgical management of complicated hernias. The reported frequency of bowel resection varies widely between series and depends mainly on the duration of symptoms and the age of the patient.[17-19] The use of prosthetic mesh in the presence of strangulation, and especially after bowel resection, has been questioned because of fear of infection, although recent meta-analyses and cohort studies suggest that mesh repair can be used safely in carefully selected patients without gross contamination.[20-22] Guidelines for the emergency repair of complicated abdominal wall hernias have been published,[23] and the minimal access approach is being used increasingly even for emergency groin hernia surgery in expert hands.[24]

Most published data on complicated inguinal hernia come from retrospective series or from registries in high-income countries. Prospective data from Indian teaching hospitals, describing the clinical profile, intraoperative findings, choice of repair and short-term outcome, are limited. A clear understanding of the local profile of these patients, of the determinants of bowel gangrene and of the outcomes of the different surgical options is necessary to improve the care pathway. This study was therefore planned to evaluate these aspects in a tertiary care teaching hospital.

Aims and objectives

To study the clinical profile of patients presenting with obstructed and strangulated inguinal hernia. To document the operative findings and the surgical procedures performed. To evaluate postoperative complications, duration of hospital stay and 30-day mortality. To identify factors associated with the need for bowel resection

Study design and setting

This was a hospital-based prospective observational study conducted in the Department of General Surgery of a tertiary care teaching hospital in India, which receives patients from the surrounding urban and rural districts through the emergency department and by referral from peripheral centres. The study period was 12 months, from January 2019 to December 2019. Approval was obtained from the Institutional Ethics Committee before enrolment. Written informed consent was obtained from every participant or, if the patient was too unwell, from the legally authorised relative.

Study population and sample size

Consecutive adult patients (aged 18 years or more) admitted through the emergency department with a clinical diagnosis of obstructed or strangulated inguinal hernia, who underwent emergency surgery during the study period, were enrolled. Based on the average annual emergency hernia admissions to the department, a sample of 100 patients was considered adequate for descriptive analysis during the study period.

Inclusion criteria

• Age 18 years or more, of either sex.
• Primary or recurrent inguinal (indirect, direct or pantaloon) hernia presenting as obstructed or strangulated and requiring emergency surgery.
• Willingness to give consent and to attend follow-up.

Exclusion criteria

• Femoral, umbilical, incisional or other abdominal wall hernias.
• Irreducible but non-obstructed (simple incarcerated) inguinal hernias managed electively.
• Patients managed conservatively or reduced by taxis and discharged without operation.
• Patients who refused consent or were lost to follow-up before 30 days.

Definitions

An obstructed hernia was defined as an irreducible hernia with clinical or radiological evidence of intestinal obstruction (vomiting, absolute constipation, distension) in which the bowel or its contents were found viable at operation. A strangulated hernia was defined as one in which the contents showed ischaemic compromise (discolouration, loss of lustre, absent peristalsis or absent mesenteric pulsation) at operation, with or without gangrene.[5] Duration of symptoms was counted from the onset of irreducibility or pain to the time of arrival at the hospital. Patients were graded using the American Society of Anesthesiologists (ASA) physical status classification.

Preoperative evaluation and resuscitation

A detailed history and a general, systemic and local examination were completed for all patients. Haemoglobin, total leukocyte count, blood urea, serum creatinine, serum electrolytes, blood glucose and an electrocardiogram were obtained. An erect abdominal radiograph was taken when obstruction was suspected, and ultrasonography of the groin or contrast-enhanced computed tomography was added where the diagnosis was uncertain. Resuscitation consisted of nasogastric decompression, intravenous fluids, correction of electrolyte imbalance, urinary catheterisation in unstable patients and a single dose of a broad-spectrum antibiotic at induction (second-generation cephalosporin with metronidazole). Surgery was performed as soon as the patient was optimised.

Operative procedure

The operations were performed or supervised by consultant surgeons under spinal, general or local anaesthesia, selected according to the patient's condition. The inguinal canal was opened, the sac identified and opened carefully, and the contents inspected. The constricting ring was released, and when the viability of the bowel was doubtful it was wrapped in warm saline-soaked gauze for ten to fifteen minutes with 100% oxygen given by the anaesthetist. Bowel that remained dusky, without peristalsis or mesenteric pulsation, was resected with end-to-end anastomosis, through the same incision or an additional midline laparotomy when needed. Non-viable omentum was resected.

For the repair, the choice of technique was left to the operating surgeon according to the viability of the contents, the degree of contamination and the age and fitness of the patient. Options included herniotomy alone in young patients with a good posterior wall, tissue repair (modified Bassini), the Desarda technique using an external oblique aponeurosis strip,[25] Lichtenstein tension-free mesh repair using a polypropylene mesh,[26,27] and transabdominal preperitoneal (TAPP) repair in stable patients treated by a surgeon experienced in the technique.[28] In general, mesh was avoided when bowel resection had been performed or there was gross contamination.

Postoperative care and follow-up

Intravenous antibiotics were continued for 48 to 72 hours (longer after resection), oral feeding was started according to the return of bowel function, and early mobilisation was encouraged. Patients were reviewed daily during admission and at 1, 2 and 4 weeks after surgery, and a 30-day outcome was recorded for all patients.

Outcome measures

The primary outcomes were the clinical profile, operative findings and the proportion needing bowel resection. Secondary outcomes were operating time, postoperative complications graded by the Clavien–Dindo classification,[29] duration of hospital stay and 30-day mortality. Surgical site infection was defined according to standard criteria. Wound dehiscence, seroma, scrotal haematoma, urinary retention, pulmonary complications, anastomotic leak and orchitis or testicular atrophy were also recorded.

Statistical analysis

Data were entered in Microsoft Excel and analysed with SPSS software (version 26.0, IBM Corp., Armonk, NY, USA). Continuous variables were expressed as mean ± standard deviation and categorical variables as frequency and percentage. The Student t-test was used for continuous variables and the chi-square test or Fisher exact test for categorical variables. A p value below 0.05 was considered statistically significant.

During the 12-month study period 100 patients who fulfilled the criteria were enrolled and all completed the 30-day follow-up. Of these, 63 (63%) had an obstructed and 37 (37%) a strangulated inguinal hernia.

3.1 Demographic profile

The age of the patients ranged from 18 to 86 years with a mean of 54.6 ± 16.2 years. The commonest age group was 61–75 years (31%), and 46% of the patients were older than 60 years. There was a marked male preponderance, with 91 men and 9 women (male : female = 10.1 : 1). Fifty-four patients were farmers or manual labourers (Table 1).

Table 1. Age and sex distribution of patients (n = 100)

Mean age 54.6 ± 16.2 years (range 18–86 years).

3.2 Clinical presentation

All patients presented with a painful, tender, irreducible swelling in the groin with absent cough impulse. Seventy-one patients (71%) were aware of a pre-existing hernia, while 29 (29%) presented with it for the first time. Only 12 patients had used a truss. Vomiting was present in 72%, absolute constipation in 66% and abdominal distension in 58%. The mean duration of symptoms before arrival was 39.4 hours; 41 patients (41%) came within 24 hours, 33 (33%) between 24 and 48 hours, and 26 (26%) after more than 48 hours. Systemic features of toxaemia such as fever (24%), tachycardia (46%) and hypotension (9%), and erythema or oedema of the overlying skin (17%) were noted mainly in late presenters (Table 2). The total leukocyte count exceeded 11,000/mm³ in 41 patients, serum creatinine was raised in 18 and an erect abdominal radiograph showed multiple air-fluid levels in 49.

Table 2. Clinical presentation (n = 100)

Percentages are of the total of 100 patients; some patients had more than one feature.

3.3 Comorbidity, risk factors and ASA grade

Raised intra-abdominal pressure factors were common: 44 patients were smokers, 21 had chronic cough or chronic obstructive airway disease, 17 had urinary symptoms attributable to prostatic enlargement and 14 had chronic constipation. Hypertension (28%) and diabetes mellitus (19%) were the commonest systemic comorbidities. Thirty-three patients (33%) belonged to ASA grade III or IV (Table 3).

Table 3. Comorbidities, risk factors and ASA grade (n = 100)

Patients could have more than one comorbidity. COPD = chronic obstructive pulmonary disease; BMI = body mass index.

3.4 Hernia characteristics

The hernia was on the right side in 58%, the left in 36% and bilateral in 6% (the symptomatic side was operated). Indirect hernias were the most frequent (74%), followed by direct (19%) and pantaloon hernias (7%). Six patients had a recurrent hernia after previous repair (Table 4).

Table 4. Hernia characteristics (n = 100)

3.5 Operative findings

The commonest sac content was small bowel, mostly ileum (57%), followed by omentum (30%). In two patients the sac contained only reactive fluid, the bowel having reduced spontaneously on induction of anaesthesia. Of the 37 strangulated hernias, 11 had gangrenous bowel requiring resection, 17 had strangulated omentum requiring omentectomy and in 9 the bowel regained viability after release and warm-saline application (Table 5). Bowel resection with end-to-end anastomosis was therefore required in 11 patients (11% of the whole series; 29.7% of the strangulated group). The small bowel was resected in ten patients and the ileocaecal region in one.

Table 5. Operative findings (n = 100)

*Percentage of the 37 strangulated hernias.

3.6 Surgical procedures

Spinal anaesthesia was used in 72 patients, general anaesthesia in 21 and local anaesthesia with sedation in 7. Lichtenstein mesh repair was the commonest procedure (66%). Tissue repair by the modified Bassini technique was performed in 17 patients, 11 of whom had undergone bowel resection and 6 had gross contamination or an unfit abdominal wall. Desarda repair was used in 6, herniotomy alone in 7 young patients and a laparoscopic TAPP repair in 4 stable patients (Table 6). Prosthetic mesh was therefore used in 70% of patients overall and in none who needed bowel resection. The mean operating time was 79.9 ± 27.3 minutes.

Table 6. Anaesthesia and surgical procedures (n = 100)

TAPP = transabdominal preperitoneal. Mean operating time 79.9 ± 27.3 minutes.

3.7 Obstructed versus strangulated hernias

Patients with strangulated hernia were older (58.9 ± 16.1 versus 52.1 ± 15.8 years, p = 0.042) and presented later: 48.6% of the strangulated group arrived after 48 hours compared with 12.7% of the obstructed group (p < 0.001). Fever, tachycardia, leukocytosis and ASA grade III or above were all significantly more frequent in strangulation. Strangulation was also associated with longer operations, a longer hospital stay, more surgical site infections and a numerically higher, though not statistically significant, mortality (Table 7).

Table 7. Comparison of obstructed and strangulated hernias

Student t-test for continuous variables; chi-square or Fisher exact test for categorical variables.

3.8 Factors associated with bowel resection

On univariate analysis, presentation after more than 48 hours, ASA grade III or IV, fever, leukocytosis and skin erythema over the hernia were significantly associated with bowel resection. Age above 60 years and female sex showed a trend towards resection which did not reach statistical significance (Table 8). Because of the small number of events no multivariate model was fitted.

Table 8. Factors associated with bowel resection (univariate analysis)

Fisher exact test.

3.9 Postoperative complications

Postoperative complications occurred in 45 patients (45%), and some had more than one. Surgical site infection was the commonest (14%): 11 were superficial and responded to dressings and antibiotics, whereas 3 were deep and needed drainage. Surgical site infection was significantly more frequent after bowel resection (5 of 11, 45.5%) than without it (9 of 89, 10.1%; p = 0.007). Scrotal haematoma or oedema (12%), urinary retention (11%) and seroma (9%) were the other frequent problems. There was one anastomotic leak, which was reoperated on and the patient recovered. No mesh required removal during the 30-day period (Table 9).

Table 9. Postoperative complications (n = 100)

A patient could have more than one complication.

When graded by the highest-grade complication per patient using the Clavien–Dindo classification, 55 patients had an uneventful recovery, whereas 29 had minor complications (grade I–II). Sixteen patients had complications of grade IIIa or above (Table 10).

Table 10. Clavien–Dindo grading of complications (highest grade per patient)

ICU = intensive care unit.

3.10 Hospital stay and mortality

The mean hospital stay was 6.2 ± 3.4 days. It was 4.8 ± 1.9 days in the obstructed group and 8.7 ± 4.1 days in the strangulated group (p < 0.001), and was 11.8 ± 4.6 days in patients who needed bowel resection against 5.6 ± 2.4 days in those who did not (p < 0.001). Four patients died within 30 days, giving an overall mortality of 4%. Three deaths occurred in the strangulated group after bowel resection (3 of 11, 27.3%; two due to septicaemia with multiple organ dysfunction, one due to aspiration pneumonia and acute respiratory distress syndrome) and one occurred in an elderly ASA IV patient with obstructed hernia who sustained a myocardial infarction. No patient who had a strangulated hernia without bowel resection died (0 of 26) (Table 11). There were no hernia recurrences at the 30-day review.

Table 11. Hospital stay and 30-day mortality

Mortality in the resection group versus the non-resection group: p = 0.001 (Fisher exact test).

This prospective study of 100 patients adds to the limited Indian data on the profile and outcome of obstructed and strangulated inguinal hernias treated in a teaching hospital. The principal findings were that complicated hernias occurred predominantly in middle-aged and elderly men, that a long-standing hernia was known to most patients, that almost one-quarter of the patients arrived more than 48 hours after the onset of symptoms, that one in nine patients required bowel resection, and that delay and physiological compromise at presentation were the strongest correlates of bowel gangrene and death.

The mean age of 54.6 years and the male predominance (91%) in our series are consistent with the known epidemiology of groin hernia, where the lifetime risk is almost ten times higher in men.[30] Older age in the strangulated group (58.9 versus 52.1 years) agrees with the observation of Kulah et al. that emergency hernia repair in elderly patients is associated with a higher rate of bowel resection and a markedly greater risk of postoperative complication and death.[31] Similar conclusions were reached in a Spanish series of incarcerated groin hernias in adults, which emphasised the influence of age and associated disease on outcome. The 9% proportion of women in our series is probably higher than their share of all inguinal hernias because women have a proportionately greater chance of presenting with a complication, as reflected in the observation in the earlier literature that strangulation occurs more often in women.[32] We found a trend towards bowel resection in women (27.3% of resections versus 6.7% of non-resections) but this was not statistically significant, which may be due to the small number of women (n = 9).

The most important finding was the delay in presentation. The mean duration of symptoms was 39.4 hours, 26% of patients presented after 48 hours, and presentation after 48 hours was the factor most strongly associated with bowel resection (81.8% of resected patients versus 19.1% of non-resected patients; p < 0.001). Delay is a well recognised determinant of outcome in series from other parts of the world, and the interval reported here is probably longer than that in high-income countries because of the barriers peculiar to our setting, such as the travel distance to a tertiary hospital, initial consultation with a local practitioner or traditional healer, repeated attempts at manual reduction at home, and financial constraints. The Indian experience published from tertiary centres similarly highlights the large pool of neglected, long-standing groin hernias that eventually present as emergencies. In our study, 71% of the patients knew of their hernia before the event, which suggests that a substantial fraction of emergencies could have been avoided by elective repair. In contrast to the high-income countries where watchful waiting is a legitimate option for minimally symptomatic men, a policy of non-operative management cannot be recommended with the same confidence where follow-up and access to emergency care are not assured. We believe that community education, early referral from primary health centres and an expansion of elective hernia surgery, including day-care repair under local anaesthesia, are necessary.

Vomiting, constipation and distension in two-thirds of the patients reflected the high frequency of intestinal obstruction, while fever, tachycardia, leukocytosis and skin changes were characteristic of strangulation and were all significantly more frequent in this group. These findings have been repeatedly shown to be markers of ischaemia and bacterial translocation and agree with the findings of the larger series from China, in which leukocytosis, fever and a long duration of symptoms were independent predictors of bowel resection.[18] The predominance of indirect hernias (74%) in our study is the expected pattern, because the narrow, rigid deep ring is the usual site of constriction. We excluded femoral hernias, which carry a much higher risk of strangulation and bowel resection than inguinal hernias and have a higher postoperative mortality after emergency repair.[33] Their exclusion is a deliberate strength of the study, because it keeps the group homogeneous, though it also means that we cannot describe the complete spectrum of emergency groin hernias.

Small bowel (usually ileum) was the content in 57% of cases and omentum in 30%, which is in line with the literature. The overall bowel resection rate was 11%, and 29.7% in the strangulated group. Reported resection rates in the literature vary widely according to the proportion of strangulated hernias in the series, the delay in presentation and the proportion of elderly patients, so that direct comparison between studies must be made with caution. The rate we report is within the range reported by single-centre series. Careful assessment of bowel viability is the key intraoperative step. The use of warm saline, oxygen and observation for peristalsis and mesenteric pulsation for 10 to 15 minutes, as in our protocol, avoided unnecessary resection in nine patients with a dusky loop. We believe that spontaneous reduction of the contents before the sac is opened is a recognised hazard: in two of our patients the sac contained only reactive fluid, and when this happens the surgeon must explore the abdomen or at least examine the reduced bowel if there is any suspicion of ischaemia, a point also stressed in guidelines.

The choice of repair in an emergency is determined by the viability of the bowel and the degree of contamination. Mesh was used in 70% of our patients and was not used in any patient needing resection. There were no mesh infections requiring removal at 30 days, and the overall surgical site infection rate in the mesh group was low (see below). These findings are consistent with a meta-analysis which found that mesh repair for strangulated inguinal hernia was not associated with a higher risk of surgical site infection or recurrence compared with non-mesh repair, although the authors pointed out that the included studies were non-randomised and that the risk after bowel resection could not be assessed,[20] and with a 10-year series of prosthetic mesh repair in acutely incarcerated and strangulated groin hernias that found acceptable wound infection rates and low recurrence.[21] A multicentre comparative study of incarcerated hernia surgery with and without mesh similarly reported that mesh could be used with an acceptable short-term outcome when the bowel was not resected.[22] The European Hernia Society guidelines recommend a mesh repair in emergency conditions unless there is bowel necrosis or gross contamination, in which case tissue repair is acceptable,[34,35] and our practice was in accordance with this recommendation. The Desarda technique, which is an Indian innovation using a strip of external oblique aponeurosis, offers a mesh-free, physiological repair that may be useful in contaminated fields, but it needs further evaluation by randomised trials.[25] We used the Lichtenstein repair in most patients because of its reproducibility, low recurrence and the experience of our surgeons.[26,27] Registry data have shown that the repair method affects the subsequent risk of reoperation for recurrence,[36] and long-term follow-up of our patients is therefore necessary before firm conclusions can be drawn about recurrence.

Laparoscopic repair was done in only four stable patients. The IEHS guidelines state that the laparoscopic approach can be used for incarcerated hernias in experienced hands, and that it permits inspection of the bowel and conversion to laparotomy if needed.[28] Indian centres have made major contributions to minimal access hernia surgery and to the long-term evaluation of the TEP and TAPP techniques,[37,38] but the availability of the skills and of the equipment during emergency hours is still limited in many teaching hospitals. The preperitoneal approach to complicated groin hernias described by Stoppa also remains a useful alternative when the posterior wall is involved.[39]

In our study, 45% of the patients had at least one complication, and 16% had a complication of grade IIIa or higher. Wound-related problems such as surgical site infection, seroma and scrotal haematoma predominated, which is expected since the tissues are oedematous and sometimes contaminated, the operation is performed in non-optimised patients, and the incidence of wound problems is increased after bowel resection (45.5% versus 10.1%). A Danish nationwide study of 26,304 herniorrhaphies found that emergency surgery was associated with a higher rate of complications and re-operations than elective surgery,[40] and Abi-Haidar et al. reported significantly higher morbidity and mortality for acute groin hernia surgery compared with elective surgery in a national surgical quality database.[41] Obesity and nutritional status also influence both the presentation and the outcome of groin hernias.[42] The Clavien–Dindo grading, which is validated and simple to use in a surgical audit,[29,43] gave us a clearer view of the burden of morbidity than a simple list of complications, and we suggest that it should be used systematically in emergency hernia studies in India so that results are comparable.

The overall mortality of 4% is higher than the mortality of elective inguinal hernia repair, which is close to zero in healthy patients, and is within the range of the mortality reported for emergency groin hernia surgery in population-based studies from the West, where mortality is concentrated among the elderly and among those needing bowel resection.[11-13] Strangulation without bowel resection was not lethal in our series (0 of 26), whereas 27.3% of the patients needing resection died. This difference illustrates that the principal determinant of death is the stage at which the patient reaches the surgeon and that the mortality of strangulation is largely a consequence of delayed presentation, sepsis and comorbidity. Studies from Africa, where delay is greater, report even higher mortality,[16] and the trend in the United States for increasing emergency repairs in the elderly is a warning that the problem is not limited to low-resource settings.[14,15]

Strengths and limitations

The strengths of this study are its prospective design, consecutive enrolment, uniform definitions, the use of a standard complication classification and a complete 30-day follow-up. There are limitations. It is a single-centre study with a modest sample size, so that the findings may not be generalisable to all regions of India and the estimates for infrequent events such as death and anastomotic leak are imprecise. The decision about the repair technique was based on the preference of the surgeon, so that a comparison of the techniques is subject to selection bias. Because there were only 11 resections, we could not perform a multivariate analysis, and the associations reported are unadjusted. The follow-up was limited to 30 days, which is too short to assess recurrence, chronic groin pain and testicular atrophy, and we did not include the cost of treatment or the economic effect on the patients. Multicentre prospective studies with longer follow-up are needed.

Obstructed and strangulated inguinal hernias in this series occurred mainly in middle-aged and elderly men who were aware of a pre-existing hernia but presented late. Over one-third of the hernias were strangulated, 11% of the patients required bowel resection and the overall mortality was 4%, concentrated in patients who needed resection. Presentation after 48 hours, ASA grade III or above, fever, leukocytosis and skin changes were significantly associated with bowel resection. Patients with obstructed hernia and those with strangulated hernia without resection had a good outcome. The mesh repair in clean fields and tissue repair when bowel resection or contamination was present were reasonable options in the emergency setting. Early elective repair of symptomatic hernias, public and primary care awareness of the warning signs, and prompt referral and resuscitation can decrease the burden of emergency hernia surgery and its complications in our region.

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