How Much Does Shouldice Hernia Repair Cost For Us Citizens

Can J Surg. 2022 Feb; 59(one): 19–25.

Linguistic communication: English | French

Recurrence of inguinal hernias repaired in a large hernia surgical specialty infirmary and general hospitals in Ontario, Canada

Abstract

Background

The effect of infirmary specialization on the chance of hernia recurrence after inguinal hernia repair is not well described.

Methods

We studied Ontario residents who had chief elective inguinal hernia repair at an Ontario hospital between 1993 and 2007 using population-based, administrative wellness data. We compared patients from a big hernia specialty infirmary (Shouldice Hospital) with those from full general hospitals to determine the adventure of recurrence.

Results

We studied 235 192 patients, 27.seven% of whom had surgery at Shouldice hospital. The age-standardized proportion of patients who had a recurrence ranged from 5.21% (95% confidence interval [CI] 4.94%–5.49%) amidst patients who had surgery at the lowest volume general hospitals to four.79% (95% CI 4.54%–5.04%) who had surgery at the highest book general hospitals. In contrast, patients who had surgery at the Shouldice Hospital had an historic period-standardized recurrence risk of 1.15% (95% CI 1.05%–ane.25%). Compared with patients who had surgery at the lowest volume hospitals, hernia recurrence amidst those treated at the Shouldice Hospital was significantly lower after adjustment for the effects of age, sex, comorbidity and income level (adjusted take chances ratio 0.21, 95% CI 0.19–0.23, p < 0.001).

Conclusion

Inguinal hernia repair at Shouldice Hospital was associated with a significantly lower run a risk of subsequent surgery for recurrence than repair at a general hospital. While specialty hospitals may have better outcomes for handling of common surgical conditions than general hospitals, these benefits must be weighed confronting potential negative impacts on clinical care and the financial sustainability of full general hospitals.

Résumé

Contexte

L'effet de la spécialisation des hôpitaux sur le risque de récurrence de la hernie inguinale après sa réparation n'a pas été bien décrit.

Méthodes

À partir des données administratives de santé de la population, nous avons étudié des patients ontariens ayant subi une réparation de hernie inguinale primaire non urgente dans un hôpital de 50'Ontario entre 1993 et 2007. Nous avons comparé les patients opérés dans un grand hôpital spécialisé cascade les hernies (Hôpital Shouldice) aux patients opérés dans les hôpitaux généraux afin de déterminer le risque de récurrence.

Résultats

Nous avons ainsi étudié 235 192 patients, dont 27,7 % ont subi leur intervention chirurgicale à l'Hôpital Shouldice. La proportion standardisée selon fifty'âge de patients ayant eu une récurrence a varié de 5,21 % (intervalle de confiance [IC] de 95 % 4,94 %–5,49 %) chez les patients ayant subi fifty'intervention dans les hôpitaux généraux où le volume est moindre, à four,79 % (IC de 95 % four,54 %–v,04 %) qui ont subi leur intervention dans les hôpitaux généraux où le volume est plus élevé. En revanche, les patients qui ont subi leur intervention chirurgicale à l'Hôpital Shouldice ont présenté un risque de récurrence standardisé selon fifty'âge de i,fifteen % (IC de 95 % ane,05 %–1,25 %). Comparativement aux patients ayant subi leur intervention dans les hôpitaux où le volume est moindre, la récurrence de la hernie chez les patients traités à l'Hôpital Shouldice a été considérablement moindre après ajustement pour tenir compte des effets de 50'âge, du sexe, des comorbidités et du niveau de revenu (risque relatif ajusté 0,21, IC de 95 % 0,nineteen–0,23, p < 0,001).

Conclusion

La réparation des hernies inguinales à l'Hôpital Shouldice a été associée à un risque bien moindre d'intervention chirurgicale subséquente pour récurrence comparativement à la réparation effectuée dans un hôpital général. Les hôpitaux spécialisés peuvent avoir de meilleurs résultats lors du traitement des problèmes chirurgicaux courants comparativement aux hôpitaux généraux, mais ces avantages doivent être soupesés en tenant compte des impacts négatifs potentiels sur les soins cliniques et la viabilité financière des hôpitaux généraux.

Inguinal hernia is a mutual trouble, affecting more than one-quarter of men during their lifetime. Surgical repair of inguinal hernia is one of the most frequent surgical procedures performed, with an estimated 800 000 hernia repairs performed in the United States each year.^one Since inguinal hernia repair is usually an convalescent process and complications are uncommon, hernia recurrence is a cardinal quality mensurate. Hernia recurrence risk can achieve up to 15%, depending on a variety of factors, including surgeon expertise,² and is commonly used equally an event mensurate in evaluative studies of hernia repair.^three

Ambulatory surgical centres and specialty hospitals provide care to patients with specific bug, such as elective cardiac or orthopedic weather condition.⁴ Proponents of specialty hospitals abet their potential benefits in terms of quality, efficiency and price of care. The loftier volume of procedures performed at specialty hospitals may largely explain why the reported outcomes of care are oftentimes meliorate than those at general hospitals.^v Critics of specialty hospitals point out their potential to "cream skim" profitable and low-gamble episodes of care.⁴ The Shouldice Hospital in Toronto, Ont., is a surgical specialty hospital focused exclusively on the surgical treatment of intestinal wall hernias, performing thousands of hernia procedures each twelvemonth and accounting for a large proportion of all such operations performed in Ontario. Surgeons at the Shouldice Hospital typically perform 20 times more than hernia repairs than surgeons in general hospitals, making it an extreme outlier in procedure volume. The Shouldice Hospital has been prominently cited as a prototypical surgical specialty facility^{half dozen} and every bit a business model for the type of "focused factory" that could translate the efficiencies seen in the manufacturing industry to health intendance. Although there are reports of low rates of hernia recurrence amid patients who had surgery at the Shouldice Hospital, there are no published population-based studies.

The purpose of the present study was to compare hernia recurrence rates among patients having principal elective inguinal hernia repair at the Shouldice Hospital with those having surgery at full general hospitals in Ontario. We sought to make up one's mind whether surgery at the Shouldice Hospital was associated with a lower take chances of hernia recurrence and how the risk of recurrence was influenced past procedure volume among those treated at general hospitals.

Methods

Written report overview

Nosotros conducted a retrospective cohort study using population-based administrative health data for the province of Ontario. All Ontario residents who underwent primary elective inguinal hernia repair in Ontario between January. 1, 1993, and Dec. 31, 2007, were followed until Mar. 31, 2010, to assess for hernia recurrence. We were interested in determining whether the Shouldice Hospital — a specialty hospital for hernia surgery — had a lower rate of inguinal hernia recurrence than general hospitals later bookkeeping for surgical volume.

Data sources

We used encrypted, individual level authoritative data from the Ontario Health Insurance Programme (OHIP) physician billing database, the Canadian Institute for Health Information Hospital Discharge Abstract Database (CIHI-DAD) and the Registered Persons Database (RPDB). These data sets were held securely in a linked, deidentified form and analyzed at the Establish for Clinical Evaluative Sciences. These databases are considered to be population-based and valid for the ascertainment of surgical procedures, including inguinal hernia repair.⁷ ^, ⁸ The enquiry ethics lath of Sunnybrook Wellness Sciences Centre approved our study protocol.

Study participants

Nosotros identified Ontario residents anile 18–xc years who underwent primary constituent nonrecurrent inguinal hernia repair between Jan. i, 1993, and Dec. 31, 2007. Inguinal hernia repairs were not eligible for inclusion in the study if they were coded as massive inguinal hernias or strangulated or incarcerated hernias. We included the first eligible inguinal hernia repair for patients who had more than than 1 repair during the study menses; the data sources did not distinguish whether a hernia repair was a right- or left-sided procedure.

Exposures

For each participant, nosotros measured the volume of elective inguinal hernia surgeries performed at their infirmary in the yr before surgery and categorized them into four equal groups (quartiles). Nosotros likewise identified the infirmary where the hernia surgery was done. While the number of hospitals varied during the report period owing to openings, closings and amalgamations, more than 100 general hospitals performed hernia surgery in each yr of the report menses. Because the volume of hernia repairs done at the Shouldice Hospital was substantially larger than all other hospitals, this hospital was categorized separately.

Several variables that might influence inguinal hernia recurrence were measured. These included age, sex, rurality, wellness region and median household income in the neighbourhood of residence. We assessed comorbidity using the Johns Hopkins Example-Mix Adjusted Clinical Groups (ADG) comorbidity score.⁹ ^, ¹⁰ Overall comorbidity was estimated past summing the presence of each of the 12 Collapsed ADG Clusters (CADG) and further stratified into low and loftier comorbidity levels, with a score of 7 or greater indicating high comorbidity.

Event

The master outcome of interest was surgical repair of a recurrent inguinal hernia at any hospital in Ontario. We identified recurrence events using OHIP fee codes for recurrent hernia, regardless of whether the repair was simple or associated with an emergent presentation, such as strangulation. Hernia repair events occurring inside 2 days of an earlier primary repair were non considered to indicate hernia recurrence, since bilateral repairs were oftentimes performed sequentially.

Statistical analyses

We estimated the rate of recurrent hernia repair per 1000 person-years of follow up likewise as the overall crude and historic period-standardized proportion of participants who had a surgical recurrence. For each participant, we likewise calculated the time betwixt the engagement of the initial surgery and the earliest occurrence of recurrent hernia surgery, death, loss of registration for health services, or study end appointment (Mar. 31, 2010). The time to hernia recurrence was plotted using Kaplan–Meier survival curves and compared between hospital categories using the log rank test. Nosotros used Cox proportional hazards models to gauge the effects of the various exposures, including patient and hospital characteristics, on the time to hernia recurrence¹¹ using variance-corrected estimates to account for hospital-level clustering.¹²

We performed a number of stratified analyses to determine whether the Shouldice Hospital had substantially unlike outcomes than full general hospitals for different subgroups. We used interaction terms to test whether hernia recurrence run a risk differed according to historic period, sex, time menses of hernia repair (1993–2000 v. 2001–2007), income and comorbidity.

We performed multiple sensitivity analyses to exam whether aspects of the study blueprint influenced the written report findings. First, we analyzed only the healthiest participants in the cohort according to the CADG score. Second, we performed split up analyses for the periods 1993–2000 and 2001–2007 to account for secular changes in inguinal hernia repair techniques, such equally the employ of surgical mesh and tension-free repair.^xiii ^, ^xiv Finally, nosotros tested the extent to which pick of patients with favourable hernias ("ruby picking") influenced the results of the Shouldice Hospital. Nosotros identified patients who had a consultation with a Shouldice Infirmary surgeon between 2004 and 2006 to make up one's mind what proportion subsequently had surgery at the Shouldice Hospital or a different hospital besides as the rate of hernia recurrence in each group. All statistical analyses were done using SAS version 9.2 (SAS Constitute Inc.). We considered results to be significant at p < 0.05.

Results

Participants

A total of 235 192 patients had an eligible inguinal hernia repair in Ontario betwixt Jan. 1, 1993, and Dec. 31, 2007: 170 065 at general hospitals and 65 127 at the Shouldice Hospital. The Shouldice Infirmary accounted for 27.7% of all hernia repairs in the study, with annual volumes that were at least 6-fold greater than the highest annual volume of a full general hospital (Table 1). The median historic period of participants was 55 years, and 90% were men. Participant characteristics were similar across volume categories for general hospitals. In comparison, those having surgery at the Shouldice Hospital were more likely to reside in higher-income neighbourhoods and have a lower burden of comorbidity.

Table one

Characteristics of patients having chief inguinal hernia repair in Ontario, according to infirmary volume and specialty status (Shouldice Hospital v. general hospitals)

Feature	General hospitals past book^*				Shouldice Hospital	Overall
Feature	Quartile 1	Quartile 2	Quartile three	Quartile 4	Shouldice Hospital	Overall
No. of patients	42 427	42 644	42 346	42 648	65 127	235 192
Hospital volume, median (range)^†	61 (ane–106)	142 (107–185)	219 (186–267)	341 (268–803)	5672 (5103–5888)	—
Mean historic period, twelvemonth	57	56	56	55	54	55
Male sex, %	88.5	88.3	88.4	89.4	94.v	ninety.iii
Low income, %^‡	lx.8	threescore.ix	lx.2	56.eight	48.2	56.5
High comorbidity, %^§	27.half-dozen	29.nine	30.8	30.1	23.3	27.viii
Rural, %	42.2	15.6	eight.7	6.2	9.7	15.eight

Take a chance of hernia recurrence

A total of 9020 patients had surgical repair of an inguinal hernia recurrence during the study period (Table 2). The age-standardized proportion of patients who had a recurrence ranged from 5.21% (95% confidence interval [CI] 4.94%–5.49%) among those who had surgery in the everyman volume general hospitals to four.79% (95% CI four.54%–5.04%) of those who had surgery at highest volume general hospitals. In contrast, those who had surgery at the Shouldice Hospital had an age-standardized recurrence chance of ane.15% (95% CI 1.05%–1.25%). The cumulative probability of recurrence was significantly lower (p < 0.001) among patients who had surgery at the Shouldice Infirmary than at general hospitals, regardless of book (Fig. one).

An external file that holds a picture, illustration, etc. Object name is 0590019f1.jpg

Cumulative probability of repair of recurrent inguinal hernia, according to hospital volume and specialty condition of initial hernia repair.

Table ii

Risk of hernia recurrence co-ordinate to hospital volume and specialty condition (Shouldice Hospital v. full general hospitals)

Recurrence chance cistron	Full general hospitals by volume^*				Shouldice Hospital	Overall
Recurrence chance cistron	Quartile 1	Quartile 2	Quartile 3	Quartile 4	Shouldice Hospital	Overall
No. of patients	42 427	42 644	42 346	42 648	65 127	235 192
No. of recurrences	2163	2320	1916	1920	701	9020
Incidence (per g person-years)	5.68	half-dozen.thirty	5.32	4.97	one.07	iv.27
Crude risk^†	5.ten	five.44	iv.52	4.50	i.08	3.84
Age-standardized risk (95% CI)^‡	5.21 (iv.94–v.49)	v.63 (five.35–5.91)	four.90 (4.64–5.17)	4.79 (iv.54–5.04)	one.15 (1.05–one.25)	three.95 (three.86–4.05)

The reduction in recurrence run a risk observed at the Shouldice Hospital persisted later on accounting for potentially confounding variables. Compared with patients who had surgery at the lowest book hospitals, hernia recurrence amidst those treated at the Shouldice Hospital was significantly lower after aligning for the furnishings of age, sex, CADG and income level (adjusted gamble ratio [Hour] 0.21, 95% CI 0.xix–0.23, p < 0.001; Tabular array iii). Compared with patients having surgery at full general hospitals in the lowest volume quartile, the adjusted relative chance of recurrence for those who had surgery at full general hospitals in the highest volume quartile was 0.94 (95% CI 0.89–1.00, p = 0.06). Analyses limited to only patients with low burden of comorbidity showed similar results to the main assay.

Table 3

Adapted risk^* of hernia recurrence amongst persons having primary constituent inguinal hernia repair in Ontario

Variable	HR (95% CI)	p value
Hospital category	—	—
General hospitals^†	—	—
Quartile 1^‡	1.00	—
Quartile two	1.14 (1.07–1.21)	< 0.001
Quartile 3	1.03 (0.97–ane.10)	0.33
Quartile 4	0.94 (0.89–1.00)	0.06
Shouldice Hospital	0.21 (0.19–0.23)	< 0.001
Age (per year)	1.01 (ane.01–1.01)	< 0.001
Female sexual activity	1.29 (ane.20–1.39)	< 0.001
Income quintile	—	—
ane (Everyman)^‡	1.00	—
2	ane.01 (0.94–1.08)	0.86
3	0.96 (0.89–1.02)	0.18
four	ane.02 (0.95–one.09)	0.58
5 (Highest)	i.01 (0.94–ane.08)	0.81
Year
1993–1997^‡	1.00
1998–2002	0.66 (0.63–0.70)	< 0.001
2003–2007	0.51 (0.48–0.54)	< 0.001

Stratified analyses

Compared with the chance of recurrence in patients who had surgery at general hospitals, the take a chance of recurrence was lower in those who had a hernia repair at the Shouldice Hospital for each subgroup examined (Fig. 2). However, the result on reduction of hernia recurrence was larger among patients younger than 55 years, men and patients with fewer comorbidities. Patients who had surgery between 1993 and 2000 had a larger benefit than those who had surgery between 2001 and 2007 at the Shouldice Infirmary.

An external file that holds a picture, illustration, etc. Object name is 0590019f2.jpg

Hazard ratios for repair of recurrent inguinal hernia, by age, sex, fourth dimension menstruation, income and comorbidity. CI = confidence interval.

A total of 6566 patients had a consultation with a surgeon at the Shouldice Hospital between 2004 and 2006 and later had an inguinal hernia repair. Of these, 633 (ix.6%) had their surgery at a general hospital instead of the Shouldice Hospital; a recurrence later adult in 20 of them (3.2%).

Discussion

In a population-based report of patients having master constituent repair of an inguinal hernia in Ontario, we institute that those who had surgery at the Shouldice Hospital — a specialty hospital for hernia repair and an extreme loftier outlier for surgical procedure volume — had more a 4-fold lower chance of recurrence requiring subsequent surgical repair than those whose initial surgery was done at a general hospital. This effect could not be explained by differences among patients who had surgery at different types of hospitals or by selection of patients at particularly low risk of hernia recurrence at the Shouldice Hospital. Our findings regarding hernia recurrence, the cardinal upshot measure out for hernia repair, suggest that increasing the number of people having inguinal hernia surgery at "focused factories" would result in improved surgical outcomes.

Results in relation to other studies

In randomized trials of hernia repair, the Shouldice technique of hernia repair was associated with fewer recurrences than tissue repairs, but there was no advantage over tension-gratuitous repairs using prosthetic mesh.¹⁵ ^– ²⁴ The reasons why the Shouldice Hospital performed so much better in our study than in the clinical trials is not clear. In addition to performing a specific blazon of hernia repair in a very reproducible fashion at the Shouldice Hospital,²⁵ ^, ²⁶ a diversity of processes of care are followed: patients are kept in hospital for several days after hernia repair, strict selection criteria are applied, and the surgeons perform extraordinarily large numbers of hernia surgeries. While nosotros did not identify a statistically significant issue of hospital book on recurrence among patients treated at general hospitals, our findings did advise an underlying clan, similar to other studies that demonstrated an influence of surgical volume on recurrence and other outcomes of inguinal hernia repair.²⁷ ^– ²⁹

Strengths and limitations

The strengths of our study include its large size and population-based sampling, the longitudinal assessment of surgical recurrence regardless of where it was repaired and our ability to identify patients who had surgery at the Shouldice Hospital.

Our study had several limitations. We lacked detailed clinical information on smoking; obesity; and hernia characteristics, such as size, all of which tin influence recurrence gamble. Although about of the hernia repairs among people who had surgery at the Shouldice Hospital were likely to be Shouldice repairs, we could non make up one's mind the specific surgical technique used in other hospitals, including whether repairs were open, laparoscopic, tension-free or "tissue" repairs. Because this written report was limited to Ontario residents, we lacked information on procedures and consequence events for people from outside the province who had surgery in Ontario, many of whom would accept had surgery at the Shouldice Hospital. Nosotros measured merely hospital volume and not surgeon book and therefore cannot exclude the effects of surgeon volume and expertise. Because recurrence was defined as surgical repair of a recurrent hernia, we could not detect subclinical recurrences, nor could nosotros place recurrences among patients who did not choose to have their recurrent hernia repaired.³⁰ We were not able to measure differences in wound complications, which may occur due to surgical technique and suture materials. Finally, our data did non distinguish betwixt left- and correct-sided inguinal hernias. For patients with a surgical recurrence who had ii prior inguinal hernia repairs, we attributed the recurrence to the hospital where the first primary inguinal hernia was repaired. To the extent that people had 2 inguinal hernias repaired at 2 different hospitals, this error would accept falsely attributed the recurrence to the incorrect hospital approximately one-half the fourth dimension. Since all of these types of misclassification error are nondifferential and would bias our findings toward the zip hypothesis of finding no event of the Shouldice Hospital, it is unlikely that any of these sources of mistake biased our findings in favour of the results we observed.

Study implications

There are 2 main explanations for our master findings regarding surgical recurrence. Either surgical care is essentially meliorate at a surgical specialty infirmary, or patients at substantially lower adventure of recurrence were preferentially selected for surgery. Patients having surgery at the Shouldice Infirmary were generally healthier and had a higher household income. There was no evidence that use of local anesthesia at the Shouldice Hospital led to more medically loftier-risk patients having surgery there. Information technology is possible that the specialty hospital operated on patients with highly favourable hernias, or on minimally detectable hernias on which other surgeons would not operate.³¹ Our results practice not provide support to the hypothesis that patient choice alone can explain the observed results. An judge of the extent of out-option is the ten% of patients who had a consultation with a surgeon at the Shouldice Hospital but subsequently had surgery at a general hospital. Only an extraordinarily loftier recurrence rate amid these patients would explicate the large effect we observed; the bodily recurrence risk of approximately three% among these patients suggests a very limited outcome of patient selection. While our findings advise that specialty hospitals treat patients with selected and favourable demographic characteristics, we did non detect that they preferentially selected patients based on expected treatment outcome. The Shouldice Hospital is unique in that it is not only just a very high-volume specialty surgical hospital, merely also the champion of a surgical technique that is rarely used in other hospitals. The favourable results we observed regarding hernia recurrence at the Shouldice Hospital may exist associated with surgical volume, surgical technique and processes of care, or with all of these factors.

Our findings raise important questions for time to come studies. What processes of care explain the hit differences in outcome nosotros observed at the Shouldice Hospital? While it is an extreme outlier in terms of surgical volume, the rate of recurrence afterwards surgery at the specialty infirmary was essentially improve than that at fifty-fifty the highest volume general hospitals. The importance of factors such equally operative technique, patient training, postoperative intendance, or other processes of care are not clear, and ameliorate understanding of these issues will make up one's mind the extent to which the improved outcomes can exist achieved in general hospitals. Finally, if surgical specialty hospitals can achieve substantially improve outcomes than general hospitals, does it brand sense to encourage more routine surgical care to exist provided in these settings? Any potential benefits in clinical outcomes must ultimately be considered in the context of the negative consequences of specialty hospitals, such as maintaining expertise in surgical care at full general hospitals and drawing profitable episodes of care away from full general hospitals that rely on acquirement from elective surgery to subsidize more than costly types of hospital care.³²

Decision

Inguinal hernia repair at a large hernia specialty hospital was associated with a essentially lower risk of subsequent surgery for hernia recurrence than repair at a general hospital. These results could not be explained entirely on the ground of surgical volume, patient selection or confounding factors. While specialty hospitals may take amend outcomes for treatment of mutual surgical conditions than general hospitals, these benefits must be weighed confronting potential negative impacts on clinical care and the fiscal sustainability of general hospitals.

Footnotes

This study was supported by the Establish for Clinical Evaluative Sciences (ICES), which is funded past an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). The opinions, results and conclusions reported in this paper are those of the authors and are independent from the funding sources. No endorsement by ICES or the Ontario MOHLTC is intended or should be inferred. The authors take no conflict of interest related to this research, and take no affiliation with the Shouldice Infirmary.

Competing interests: None alleged.

Contributors: C. Bell, T. Stukel and D. Urbach designed the study. A. Malik and D. Urbach acquired the information, which all authors analyzed. A. Malik and C. Bong wrote the article, which all authors reviewed and approved for publication.

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