Long-term outcomes of component separation for abdominal wall hernia repair
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Authors: Fry BT, Schoel LJ, Howard RA, Thumma JR, Kappelman AL, Hallway AK, Ehlers AP, O’Neill SM, Rubyan MA, Shao JM, Telem DA
Affiliation: University of Michigan, Ann Arbor
Journal: JAMA Surgery, January 2025
PMID: 39535784
Key takeaways
Component separation use surged: 1.6% to 21.4% of inpatient repairs from 2007–2021.
Despite being used for more complex patients, component separation had lower 10-year operative recurrence than repairs without it.
The absolute recurrence difference was modest: 11.2% vs 12.9% at 10 years, favoring component separation.
High-volume surgeons had statistically lower recurrence, but the clinical effect was small: 11.9% vs 13.6%.
Claims data cannot assess hernia size, anterior vs posterior release, true clinical recurrence, or appropriateness of technique use.
Background
Component separation is used to achieve midline fascial closure in large or complex ventral hernias. Its use has expanded rapidly, especially after renewed interest in posterior component separation and transversus abdominis release, but population-level long-term recurrence data have been limited.
Objective
To evaluate contemporary national trends in component separation use and compare long-term operative recurrence after ventral hernia repair with versus without component separation. A secondary aim was to determine whether surgeon component-separation volume was associated with recurrence.
Methods
Design: Retrospective cohort study using 100% Medicare administrative claims data; observational Level III evidence.
Study period: January 1, 2007, through December 31, 2021; analysis performed 2024.
Population: Adults 18 years or older undergoing elective inpatient ventral hernia repair.
Hernia types included: Ventral, incisional, umbilical, and epigastric anterior abdominal wall hernias.
Exclusions:◦ Prior hernia repair within at least 2 years before index operation.◦ Repairs coded as recurrent ventral hernia.◦ Non–Fee-for-Service Medicare patients.◦ Cases lacking concurrent CPT code for hernia repair.
Exposure: Component separation identified by CPT code 15734 for myofascial release with concurrent ventral hernia repair coding.
Primary endpoints:
Annual proportion of inpatient ventral hernia repairs using component separation.
Operative recurrence up to 10 years.
Secondary endpoint:
Operative recurrence after component separation stratified by surgeon volume.
Recurrence definition: Subsequent hernia operation; this is operative recurrence, not true clinical recurrence.
Statistical approach: Cox proportional hazards models adjusted for age, sex, race and ethnicity, comorbidities, hernia subtype, operative approach, mesh use, component separation, and year of surgery. Hospital-level clustering was used for the primary model; surgeon-level clustering was used for surgeon-volume analysis.
Results
Cohort characteristics
Total patients: 218,518 Medicare beneficiaries.
Component separation: 23,768 patients, or 10.9%.
No component separation: 194,750 patients, or 89.1%.
Mean age: 69.1 years.
Sex: 58.5% female, 41.5% male.
Median follow-up: 7.2 years.
Compared with non–component separation patients, those receiving component separation were:
Slightly younger.
More often male.
More comorbid, including higher obesity prevalence.
More likely to undergo open repair.
More likely to receive mesh.
Utilization trend
Total inpatient ventral hernia repairs decreased from 17,661 in 2007 to 7,330 in 2021.
Component separation use increased from 1.6% in 2007 to 21.4% in 2021.
Operative recurrence
Adjusted cumulative operative recurrence was lower with component separation:
1 year: 0.7% with component separation vs 0.9% without.
3 years: 4.2% vs 4.9%.
5 years: 6.8% vs 7.9%.
10 years: 11.2% vs 12.9%; P = .003.
This is notable because component separation is generally reserved for larger, more complex, or multiply recurrent hernias, which should bias toward higher recurrence rather than lower recurrence.
Surgeon volume
Surgeon-specific data were available for 23,627 component separations, performed by 6,480 surgeons.
After Medicare volume adjustment:
72.4% of surgeons performed fewer than 2 component separations per year.
97.4% performed fewer than 5 component separations per year.
High-volume surgeons were defined as the top 5% by annual component separation volume.
Median annual volume:
Low-volume group: 1.2 cases/year.
High-volume group: 4.9 cases/year.
Ten-year operative recurrence:
High-volume surgeons: 11.9%.
Low-volume surgeons: 13.6%.
P = .004.
Conclusion
Component separation was associated with lower long-term operative recurrence after ventral hernia repair among Medicare beneficiaries, despite being used in patients likely to have more complex hernias. Surgeon volume was statistically associated with recurrence, but the absolute effect was small.
Strengths
Very large national cohort using 100% Medicare claims.
Long median follow-up of 7.2 years, with recurrence tracked up to 10 years.
Captures real-world practice across a broad range of surgeons, not just expert hernia centers.
Quantifies both adoption trends and long-term recurrence, which prior studies often did not.
Limitations
Operative recurrence underestimates true clinical recurrence because it only captures patients who undergo another operation.
Medicare claims lack key surgical details: hernia width, loss of domain, wound class, mesh plane, mesh type, fixation strategy, fascial closure quality, and prior abdominal wall history.
Cannot distinguish anterior component separation, posterior component separation, and transversus abdominis release.
Selection bias is unavoidable: patients selected for component separation likely differed in ways not measurable in claims.
Surgeon-volume analysis is imperfect because Medicare volume was inflated to estimate all-payer volume.
Lower recurrence in the component separation group could partially reflect inappropriate use in smaller hernias, where recurrence risk is already low.
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