Kidd, G.A.

O'Dwyer, P.J.

Whalen, H.R.

English

H. R. Whalen

G. A. Kidd

P. J. O'Dwyer

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Femoral hernias

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Easily missed?: femoral hernias

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       Whalen, H.R., Kidd, G.A. and O'Dwyer, P.J. (2011) Easily missed?: femoral hernias. British Medical Journal, 343. d7668. ISSN 0959-8138   http://eprints.gla.ac.uk/59540/  Deposited on: 31 January 2012   Enlighten – Research publications by members of the University of Glasgow http://eprints.gla.ac.uk EASILY MISSED?Femoral herniasHenry Robert Whalen clinical research fellow 1, Gillian A Kidd general practitioner2, Patrick J O’Dwyerprofessor of surgery 11University Department of Surgery, Western Infirmary, Glasgow G11 6NT, UK; 2Midlock Medical Centre, General Practice, Glasgow, UKThis is one of a series of occasional articles highlighting conditions thatmay be more common than many doctors realise or may be missed atfirst presentation. The series advisers are Anthony Harnden, universitylecturer in general practice, Department of Primary Health Care,University of Oxford, and Richard Lehman, general practitioner, Banbury.To suggest a topic for this series, please email us ateasilymissed@bmj.com.An overweight 65 year old woman visits her general practitionerwith discomfort in her right groin. On examination, thesuggestion of a reducible groin lump is noted. She is routinelyreferred to the surgical outpatient clinic with a possible diagnosisof inguinal hernia. However, two weeks later and before hersurgical appointment, she again visits her general practitioner,this time with vomiting, diarrhoea, and colicky abdominal pain.She is immediately referred to the emergency department. Anabdominal radiograph shows small bowel obstruction. She isadmitted to the surgical ward with a diagnosis of obstructedfemoral hernia and has a small bowel resection and emergencyhernia repair.What is a femoral hernia?A femoral hernia is the protrusion of a peritoneal sac throughthe femoral ring into the femoral canal, posterior and inferiorto the inguinal ligament. The sac may contain preperitoneal fat,omentum, small bowel, or other structures.Why is a femoral hernia missed?Evidence is scarce as to the reason why femoral hernias areoften missed and present as emergencies. Patients may be awareof groin discomfort or a groin lump, but they may not realiseits clinical importance and may be reluctant to seek medicalhelp. Initially some patients present to primary care with vaguesymptoms including groin discomfort that may be attributed toother disease such as osteoarthritis. As femoral hernias aretypically small, they may be easily missed on examination,particularly in obese patients. Furthermore, owing to thedifficulty in clinically distinguishing groin hernias, femoralhernias may be mistaken for inguinal hernias and referred forsurgical opinion on a non-urgent basis.3In an emergency, patients may present with signs of bowelobstruction, which include colicky abdominal pain, vomiting,and abdominal distension. About a third of patients do notcomplain of symptoms directly attributable to a hernia,4 and agroin lump is not always present. Other diagnoses, such asgastroenteritis, enlarged groin lymph node, diverticulitis, orconstipation, may be made in error.⇓Retrospective studies have observed that about 40% of herniascausing symptoms of acute bowel obstruction are missed owingto a lack of groin examination.5 6 The researchers concludedthat female patients and all patients with femoral hernia wereless likely to have a groin examination, despite signs of bowelobstruction being noted.5Why does this matter?Although femoral hernias are less common than inguinal, theyare associated with higher rates of acute complication. Thecumulative probability of strangulation for femoral hernias is22% three months after diagnosis, rising to 45% 21months afterdiagnosis, whereas the probability of strangulation for aninguinal hernia is 3% and 4.5% respectively over the same timeperiod.7Several studies have shown that acute femoral hernias and theirsubsequent complications are associated with increasedmorbidity and mortality.1 2 8-10 Examples of morbidity resultingfrom acute presentation include increased rates of bowelresection, wound infection, and cardiovascular and respiratorycomplications.10 As elective femoral hernia repair has beenshown to be a relatively safe procedure (even in patients agedover 80), it is generally accepted that femoral hernias should bereferred urgently and repaired electively.2 10 11 12Missed femoral hernia at emergency presentation delays timeto surgery.5 One study has shown an increased likelihood ofbowel resection if surgery is undertaken more than 12 hoursafter the onset of acute symptoms.13 Preoperative delay is clearlyCorrespondence to: H R Whalen Henry.Whalen@gjnh.scot.nhs.ukFor personal use only: See rights and reprints http://www.bmj.com/permissions Subscribe: http://www.bmj.com/subscribeBMJ 2011;343:d7668 doi: 10.1136/bmj.d7668 (Published 8 December 2011) Page 1 of 4PracticePRACTICEHow common are femoral hernias?• About 5000 femoral hernia repairs are carried out in the United Kingdom each year• Femoral hernias account for a fifth of all groin hernias in females but less than 1% of groin hernias in males• The 40% of femoral hernias that present acutely are associated with a 10-fold increased risk of mortality1 2linked with an increase in bowel resection, and this is associatedwith mortality rates that are about 20 times higher than thosefor patients having elective hernia repair (which would notrequire a bowel resection).2How is it diagnosed?ClinicalClassically, femoral hernias present as mildly painful,non-reducible groin lumps, located inferolateral to the pubictubercle. In contrast, inguinal hernias are found superomedially.However, femoral hernias tend to move superiorly to a positionabove the inguinal ligament, where they may be mistaken foran inguinal hernia. Differentiation of groin hernias on clinicalgrounds is therefore unreliable, irrespective of the experienceof the examining doctor.14 In patients presenting electively, onlyabout 1% of groin hernias in males are likely to be femoral,whereas the likelihood in females is about 20%.1 Clinicalexamination alone is inaccurate in differentiating groin hernia.14Therefore in females, owing to the greater prevalence of femoralhernia, consider all groin hernia to be femoral until provedotherwise.Femoral hernias may also present without a palpable lump andwith only vague symptoms of abdominal or groin pain.However, symptoms may vary and there is a lack of evidenceto predict the likelihood of a particular symptom indicating thepresence of a femoral hernia. Patients may present later withclinical features of bowel obstruction. Undertake a detailedgroin examination in all patients presenting with bowelobstruction.InvestigationsUltrasonography, magnetic resonance imaging, and computedtomography (CT) have all been shown to be accurate in detectingand differentiating groin hernias.Ultrasonography is widely available, non-invasive, and highlyaccurate in differentiating inguinal from femoral hernia—withsensitivities and specificity of 100% being reported in twostudies.15 16 Its accuracy is, however, operator dependent.Magnetic resonance imaging has been reported to be moreaccurate than ultrasonography in detecting inguinal hernia.17However, there is a lack of evidence for whether magneticresonance imaging is better than ultrasonography in detectingand differentiating groin hernia. Therefore ultrasonographyshould be the first choice for electively investigating suspectedgroin hernia as it is more widely available, less costly, andaccurate.CT scanning has been shown to be accurate in differentiatinggroin hernias. One retrospective study reports the correctidentification of 74 of 75 hernias (28 femoral and 47 inguinal),which were later confirmed at operation.18 This is broadlycomparable with the non-invasive modalities outlined above,but as there is a substantial radiation dose associated with CTscanning, it should not be used electively for investigatingsuspected groin hernia. In the acute abdomen, however, considerCT as the first choice for investigating suspected small bowelobstruction in the presence of a negative clinical examination.How is it managed?In males, a groin hernia suspected as being femoral on clinicalexamination requires urgent referral, due to the risks of acutecomplications outlined above. All groin hernia in females shouldbe urgently referred for assessment.Electively, both open and laparoscopic repair using mesh havesignificantly lower recurrence rates than repair using suturesonly.1 Open repair has the advantage that it can be performedunder local anaesthetic. No evidence suggests superiority ofeither method in the acute setting.Some research has suggested that femoral hernias may beoverlooked during repair of suspected inguinal hernias.19 Soduring surgical repair of all groin hernias examine the femoralcanal if an obvious inguinal hernia is not observed.Contributors: The authors jointly developed the idea for the manuscript,interpreted data from the literature, and drafted and revised themanuscript. All authors approved the final version. PJO’D is theguarantor.Competing interests: All authors have completed the ICMJE uniformdisclosure form at www.icmje.org/coi_disclosure.pdf (available onrequest from the corresponding author) and declare: no support fromany organisation for the submitted work; no financial relationships withany organisations that might have an interest in the submitted work inthe previous three years; no other relationships or activities that couldappear to have influenced the submitted work.Provenance and peer review: Commissioned; externally peer reviewed.Patient consent not required (patient anonymised, dead, or hypothetical).1 Dahlstrand U, Wollert S, Nordin P, Sandblom G, Gunnarsson U. Emergency femoralhernia repair. A study based on a national register. Ann Surg 2009;249:672-6.2 Nilsson H, Styliandis G, Haapamaki M, Nilsson E, Nordin P. Mortality after groin herniasurgery. Ann Surg 2007;245:656-60.3 McEntee GP, O’Carroll A, Mooney B, Egan TJ, Delaney PV. Timing of strangulation inadult hernias. Br J Surg 1989;76:725-6.4 Hjaltson E. Incarcerated hernia. Acta Chir Scand 1981;147:263-7.5 Nilsson H, Nilsson E, Angeras U, Nordin P. Mortality after groin hernia surgery: delay oftreatment and cause of death. Hernia 2011;15:301-7.6 Kjaergaard J, Nielsen M, Kehlet M. Mortality following emergency groin hernia surgeryin Denmark. Hernia 2010;14:351-5.7 Gallegos NC, Dawson J, Jarvis M, Hobsley M. Risk of strangulation in groin hernias. BrJ Surg 1991;78:1171-3.8 Malek S, Torella F, Edwards P. Emergency repair of groin hernia: outcome and implicationsfor elective surgery waiting times. Int J Clin Pract 2004;58:207-9.9 Andrews NJ. Presentation and outcome of strangulated external hernia in a district generalhospital. Br J Surg 1981;68:329-32.10 Alvarez J, Baldonedo R, Bear I, Solis J, Alvarex P, Jorge J. Incarcerated groin hernias inadults: presentation and outcome. Hernia 2004;8:121-6.11 Kemler M, Oostvogel J. Femoral hernia: is a conservative policy justified? Eur J Surg1997;163:187-90.12 Glassow F. Femoral hernia: review of 2105 repairs in a 17 year period. Am J Surg1985;150:353-6.13 Tanaka N, Uchida N, Ogihara H, Sasamoto H, Kato H. Clinical study of inguinal andfemoral incarcerated hernias. Surg Today 2010;40:1144-7.14 Hair A, Paterson C, O’Dwyer PJ. Diagnosis of a femoral hernia in the elective setting. JR Coll Surg Edinb 2001;46:117-8.15 Bradley M, Morgan D, Pentlow B, Roe A. The groin hernia—an ultrasound diagnosis. AnnR Coll Surg Engl 2003;85:178-80.16 Djuric-Stefanovic A, Saranovic D, Ivanovic A, Masulovic D, Zuvela M, Bjelovic M, et al.The accuracy of ultrsonography in classification of groin hernias according to the criteriaof the unified classification system. Hernia 2008;12:395-400.17 Van de Berg J, de Valois J, Go P, Rosenbusch G. Detection of groin hernia with physicalexamination, ultrasound and MRI compared with laparoscopic findings. Invest Radiol1999;34:739-43.18 Kitami M, Takase K, Tsuboi M, Hakamatsuka T, Yamada T, Takahashi S. Differentiationof femoral and inguinal hernias on the basis of anteroposterior relationship to the inguinalligament on multidimensional computed tomography. J Comput Assist Tomogr2009;33:678-81.For personal use only: See rights and reprints http://www.bmj.com/permissions Subscribe: http://www.bmj.com/subscribeBMJ 2011;343:d7668 doi: 10.1136/bmj.d7668 (Published 8 December 2011) Page 2 of 4PRACTICEKey points• Femoral hernias are more common in females and in people aged over 65 years and are associated with higher rates of complicationssuch as strangulation• Emergency surgery for femoral hernia is associated with a 10-fold increased risk of mortality, which is further increased by preoperativedelays• Clinical examination is unreliable in differentiating femoral from inguinal hernia• Refer all females with groin hernia for urgent assessment and management• Examine the groins of all patients presenting with signs of small bowel obstruction• Ultrasound is the first line elective investigation for suspected uncomplicated groin hernia, but in acute small bowel obstruction, CTscanning is first choice19 Mikkelsen T, Bay-Nielsen M, Kehlet H. Risk of femoral hernia after inguinal herniorrhaphy.Br J Surg 2002;89:486-8.Cite this as: BMJ 2011;343:d7668© BMJ Publishing Group Ltd 2011For personal use only: See rights and reprints http://www.bmj.com/permissions Subscribe: http://www.bmj.com/subscribeBMJ 2011;343:d7668 doi: 10.1136/bmj.d7668 (Published 8 December 2011) Page 3 of 4PRACTICEFigureInguinal hernias are usually reducible and above the inguinal ligament. Femoral hernias are often irreducible and belowthe inguinal ligament. Adapted with permission from Ellis H. Clinical anatomy. 6th ed. Blackwell Scientific, 1977For personal use only: See rights and reprints http://www.bmj.com/permissions Subscribe: http://www.bmj.com/subscribeBMJ 2011;343:d7668 doi: 10.1136/bmj.d7668 (Published 8 December 2011) Page 4 of 4PRACTICE

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Easily missed?: femoral hernias

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