Research Focus for Clinicians

A systematic review of 151 clinical studies published between January 1990 and November 2011 sought to determine the comparative effectiveness and adverse effects of different surgical options for inguinal hernia in adults and children. There were 123 randomized controlled trials (RCTs), 2 registries, and 26 studies with other designs. This summary, based on the full report of research evidence, is provided to inform discussions of options with patients and to assist in decisionmaking along with consideration of a patient’s values and preferences. However, reviews of evidence should not be construed to represent clinical recommendations or guidelines. The HTML version of this clinician research summary provides links to the full report for a more detailed discussion of the studies included in each analysis. The full report and the HTML version of this clinician research summary are available at www.effectivehealthcare.ahrq.gov/inguinal-hernia.cfm.

Background

Surgical repair of inguinal hernias is the most commonly performed general surgical procedure in the United States. Such a large volume of procedures suggests that even modest improvements in patient outcomes would substantially improve population health. The primary goals of surgery include preventing strangulation, repairing the hernia, minimizing the chance of recurrence, returning the patient to normal activities quickly, improving quality of life, and minimizing postsurgical discomfort and the adverse effects of surgery. Recurrence occurs in approximately 1 to 5 percent of cases of inguinal hernia.

Surgical procedures for inguinal hernia repair generally fall into three categories: open repair without a mesh implant (i.e., sutured), open repair with a mesh, and laparoscopic repair with a mesh. The near-universal adoption of mesh means that the most relevant questions about hernia repair involve various mesh procedures. However, mesh is not recommended for repair of pediatric inguinal hernia for several reasons including concerns about inflammatory reactions, damage to the vas deferens and/or testes, infertility, and growth-related complications. The findings from the research review presented here may inform clinical decisions by patients and surgeons, treatment recommendations by professional societies, purchasing decisions by hospitals, and coverage decisions by third-party payers.

Conclusions

The typical adult in the studies included in this review was a man in his mid 50s, who is of average weight (median body mass index 25.3 kg/m²; interquartile range 25.0–26.7), and who had an elective repair of a primary unilateral inguinal hernia. About a quarter of the men worked in physically strenuous jobs; for these men, a durable repair is important to prevent a recurrence. The results of the review may inform decisions these men face. It is unclear how these results apply to women. However, it is also unclear how these results apply to men of other age groups.

Results indicate that laparoscopic repair of an inguinal hernia is associated with faster recovery times and less risk of long-term (≥6 months) pain; for recurrent hernia, such repair may also lower the risk of another hernia recurrence. Open hernia repair, however, is familiar to more surgeons. Such repair may be associated with fewer internal injuries and may have lower recurrence rates in the context of a primary inguinal hernia. Limited evidence suggests that choosing to repair a pain-free or minimally symptomatic inguinal hernia with a Lichtenstein or tension-free mesh repair over watchful waiting may improve quality of life; however, this may not be applicable to other types of repair procedures, and the evidence on adverse effects is inconclusive.

Research found most of the meshes or fixation methods to be equivalent in their effectiveness and risk of adverse effects with only a few exceptions. There are numerous reports that the risk of recurrence decreases when a more experienced surgeon performs a repair, but there are not enough congruent studies to perform a meta-analysis.

Clinical Bottom Line

Strength of Evidence Scale

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High:		High confidence that the evidence reflects the true effect. Further research is very unlikely to change our confidence in the estimate of effect.
Moderate:		Moderate confidence that the evidence reflects the true effect. Further research may change our confidence in the estimate of effect and may change the estimate.
Low:		Low confidence that the evidence reflects the true effect. Further research is likely to change our confidence in the estimate of effect and is likely to change the estimate.
Insufficient:		Evidence is either unavailable or does not permit a conclusion.

Table 1Comparative Effectiveness of Open Versus Laparoscopic Mesh-Based Repair of Painful Primary Hernias in Adults (N = 179,338; 38 Studies)

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Outcome	Surgery Favored	Calculated Differences (95% CI)	Strength of Evidence
Hernia recurrence	Open surgery	RR = 1.43 (1.15 to 1.79); a 2.49% recurrence rate after open repair versus a 4.46% recurrence rate after laparoscopy
Length of hospital stay	Approximate equivalence	Summary difference in means = 0.33 days (0.14 to 0.52)
Return to normal daily activities	Laparoscopic	Summary weighted mean difference in days = 3.9 (2.2 to 5.6)
Return to work	Laparoscopic	Summary weighted mean difference in days = 4.6 (3.1 to 6.1)
Long-term pain	Laparoscopic	OR = 0.61 (0.48 to 0.78)
Hematoma	Laparoscopic	OR = 0.696 (0.553 to 0.875)
Wound infection	Laparoscopic	OR = 0.49 (0.33 to 0.71)
Epigastric vessel injury	Open	OR = 2.1 (1.1 to 3.9)
Small-bowel injury	Inconclusive	OR = 0.715 (0.112 to 4.555)
Small-bowel obstruction	Inconclusive	OR = 2.159 (0.583 to 8.001)
Urinary retention	Inconclusive	OR = 1.247 (0.836 to 1.861)
Spermatic cord injury	Inconclusive	In one study, 0 in 67 open repairs and 0 in 122 laparoscopic repairs In a second study, 1% after open repair (8/994) and 0.1% after laparoscopic repair (1/989)

95% CI = 95 percent confidence interval; OR = odds ratio; RR = relative risk

Gaps in Knowledge

• How the surgeon’s experience influences surgical outcomes such as recurrence and pain
• The comparative effectiveness and adverse effects of laparoscopic repair versus watchful waiting for minimally symptomatic hernias in adults
• The comparative effectiveness and adverse effects of contralateral exploration/repair versus watchful waiting in the pediatric population
• More evidence on several outcomes related to the comparisons of mesh products and fixation methods including recurrence rates, perception of a foreign body, long-term pain, and infection rates
• Clarification in future studies of whether the population includes emergent as well as elective surgeries and whether or not the findings apply equally to both populations

What To Discuss With Your Patients

• If repair or watchful waiting is the right decision for their pain-free or minimally symptomatic inguinal hernia
• How to choose between open or laparoscopic surgery if the option is available
• What to expect from open or laparoscopic repair as far as outcomes and adverse effects, including the risk of long-term chronic pain
• What to do if the hernia recurs

Resource for Patients

Surgery for an Inguinal Hernia, A Review of the Research for Adults is a free companion to this clinician research summary. It can help patients talk with their health care professionals about the decisions involved with the care and maintenance of an inguinal hernia. It provides information about:

• Types of operative treatments
• Current evidence of effectiveness and harms
• Questions for patients to ask their health care professionals

Ordering Information

For electronic copies of Surgery for an Inguinal Hernia, A Review of the Research for Adults, this clinician research summary, and the full systematic review, visit www.effectivehealthcare.ahrq.gov/inguinal-hernia.cfm. To order free print copies, call the AHRQ Publications Clearinghouse at 800-358-9295.

Source

The information in this summary is based on Surgical Options for Inguinal Hernia: Comparative Effectiveness Review, Comparative Effectiveness Review No. 70, prepared by the ECRI Institute Evidence-based Practice Center under Contract No. HHSA 290-2007-10063 for the Agency for Healthcare Research and Quality, August 2012. Available at www.effectivehealthcare.ahrq.gov/inguinal-hernia.cfm. This summary was prepared by the John M. Eisenberg Center for Clinical Decisions and Communications Science at Baylor College of Medicine, Houston, TX.

Footnotes

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A complete list of included interventions can be found in the comparative effectiveness review at www​.effectivehealthcare​.ahrq.gov/inguinal-hernia.cfm.