Retrospective Review of Complications and Revision Rates Between Isolated Talonavicular vs Talonavicular and Subtalar (Double) Arthrodesis vs Triple Arthrodesis

Abstract

Background:

Hindfoot fusion procedures are common for the treatment of end-stage arthritis or deformity. Surgical treatments for these conditions include talonavicular joint (single) arthrodesis, talonavicular and subtalar (double) arthrodesis, or talonavicular, subtalar, and calcaneocuboid (triple) arthrodesis. This study evaluated the complication rate, revision surgery rate, and hardware removal rate for those treated with either single, double, or triple arthrodesis.

Methods:

A retrospective review was conducted for patients who underwent single (Current Procedural Terminology [CPT] code 28740), double (CPT 28725 and 28740), or triple (CPT 28715) arthrodesis to treat hindfoot arthritis/deformity (International Classification of Diseases, Ninth Revision [ICD-9] code: 734, International Classification of Diseases, Tenth Revision [ICD-10] codes: M76821, M76822, and M76829) from 2005 to 2022 using the South Carolina Revenue and Fiscal Affairs databank. Data collected included demographics, comorbidities, procedure data, and postoperative outcomes within 1 year of principal surgery. Student t test, chi-squared test, and multivariable logistic regression analysis were utilized during data analysis.

Results:

A total of 433 patients were identified, with 248 undergoing single arthrodesis, 67 undergoing double arthrodesis, and 118 undergoing triple arthrodesis. There was no significant difference between single, double, and triple arthrodesis in the rate of complications, hardware removals, revision surgeries, or 30-day readmission when controlling for confounding variables. However, a decrease in Charlson Comorbidity Index (CCI) was found to be predictive of an increase in the revision surgery rate (OR = 0.46, 95% CI 0.22-0.85, P = .02).

Conclusion:

We found no difference in the rate of complications, hardware removals, or revision surgeries in those undergoing single, double, or triple arthrodesis. Surprisingly we found that a lower Charlson Comorbidity Index, indicating a healthier patient had a significant relationship with a higher rate of revision surgery. Further study including radiographic indications for surgery or the impact of overall health status on revision surgery rates may further elucidate the other components of this relationship.

Level of Evidence:

Level III, cohort study.

Keywords

Single arthrodesis double arthrodesis triple arthrodesis outcomes complications

Introduction

Hindfoot arthritis is common and can result from inflammatory disorders, primary degenerative changes, trauma, gout, and neuropathic degeneration.^16,20,25 Given the hindfoot’s important role in proper gait mechanics, arthritis in these areas can result in significant pain and physical limitations for patients.^16,20,25 Arthritis in the hindfoot can also result in abnormal foot posture and deformity of the foot, leading to greater physical limitations and causing significant morbidity for patients.²⁰ Additionally, patients can have a deformity of the hindfoot as a result of other degenerative conditions like adult-acquired flatfoot or cavovarus deformity. Surgical treatment options for end-stage hindfoot arthritis and deformity conditions can include a talonavicular joint (single) arthrodesis, talonavicular and subtalar (double) arthrodesis, or talonavicular, subtalar, and calcaneocuboid (triple) arthrodesis.^20,21,24,25 All these procedures have been demonstrated to be effective in treating the pain and functional limitations associated with several conditions of the foot and ankle.^{5,8,10,12,23,24,26,27}

There have been previous studies comparing the complication and revision surgery rate for those treated with either single, double, or triple arthrodesis.^{4,7,9,10,13,17,23} However, these previous studies focusing on comparing the complication and revision surgery rate had relatively small sample sizes, each with somewhat conflicting results.^4,9 Given the frequency of these procedures to treat numerous different pathologies, we sought to investigate the overall and individual complication rate, revision surgery rate, and hardware removal rate for those treated with either single, double, or triple arthrodesis. Additionally, we compared the rate of complications and revisions between these three procedures, to determine if one has a significantly different rate compared to the others. We hypothesize there will be a significant difference in complication or revision surgery rates between those treated with single, double, or triple arthrodesis, with those undergoing triple arthrodesis demonstrating a higher complication and revision surgery rate compared with those undergoing single or double arthrodesis because of the increased time of surgery and increased number of attempted fusion sites.

Methods

A retrospective review was conducted of patients who underwent either single, double, or triple arthrodesis between 2005 and 2022. Data were obtained from the South Carolina Revenue and Fiscal Affairs Office databank, a verified database for use in medical research.^3,6,14,19,28 This databank was composed of outpatient surgical procedures defined by reason for service, represented by an International Classification of Diseases, Ninth or Tenth Revision (ICD-9 or ICD-10) code, and the types of services received, represented by a Current Procedural Terminology (CPT) code. Patients were included in the study if they were 18 years or older and had undergone either single arthrodesis (CPT 28740), double arthrodesis (CPT 28725 and 28740), or triple arthrodesis (CPT 28715), and if their procedure was associated with a diagnosis code for flatfoot (ICD-9: 734, ICD-10: M76821, M76822, M76829). Patients were excluded from the study if their index procedure was a revision surgery of a previous single, double, or triple arthrodesis. Data collected included demographic information, Charlson Comorbidity Index (CCI), postoperative complications within 1 year, prevalence of revisions surgery within 1 year, prevalence of hardware removal surgeries within 1 year, and prevalence of 30-day all-cause unplanned readmission. All recorded complications with their corresponding ICD-9 or ICD-10 codes are displayed in Appendix 1. Continuous data were expressed as a mean and SD. Categorical data were expressed as a proportion and a percentage. Student t tests and Fisher exact chi-squared tests were used to compare continuous and categorical variables, respectively. Univariable and multivariable logistic regression analysis was used to determine independent predictors for complication rate, revision surgery rate, and hardware removal rate when both not controlling and controlling for potential confounding variables, respectively. All unadjusted variables with a P <.1 were included in the multivariable logistic regression analysis. All P <.05 were considered statistically significant.

Results

A total of 433 patients were identified for inclusion in this study. Overall, 248 (57.7%) patients underwent single arthrodesis, 67 (15.6%) underwent double arthrodesis, and 118 (27.4%) underwent triple arthrodesis. Demographic information for each group is displayed in Table 1. Of note, all procedures were performed in an outpatient setting. In comparing demographic information of those undergoing single, double, and triple arthrodesis, there was found to be a significant difference between the 3 groups in average age (44.6 vs 57.6 vs 51.1, P < .01), CCI (0.61 vs 1.6 vs 1.4, P < .01), the proportion of females operated on (81% vs 61.2% vs 58.5%), and proportion of patients >65 years old (4% vs 35.8% vs 22%, P < .1).

Table 1.

Demographic Information for Hindfoot Arthrodesis Patients.

	Single (n=248)	Double (n=67)	Triple (n=118)	P Value^a
Age, mean (SD)	44.6 (12.3)	57.6 (14.0)	51.1 (15.6)	<.01
Length of stay, mean (SD)	1.5 (1.9)	1.2 (0.79)	1.8 (2.4)	.148
Charlson Comorbidity Index, mean (SD)	0.61 (0.9)	1.6 (1.2)	1.4 (1.6)	<.01
Age ≥65 y, n (%)
No	238 (96)	43 (64.2)	96 (78)	<.01
Yes	10 (4)	24 (35.8)	26 (22)
Sex, n (%)
Male	47 (19)	26 (38.8)	49 (41.5)	<.01
Female	201 (81)	41 (61.2)	69 (58.5)
Race, n (%)
White	171 (68.9)	46 (68.7)	69 (58.5)	.29
Black	68 (27.4)	20 (29.8)	43 (36.4)
Other	9 (3.6)	1 (1.5)	6 (5.1)

Boldface indicates statistical significance (P < .05).

The number of complications for single, double, and triple arthrodesis was 12 (4.8%), 2 (3%), and 5 (4.2%), respectively; the rate of hardware removals for single, double, and triple arthrodesis was 17 (6.9%), 3 (4.5%), and 8 (6.8%), respectively; the rate of revision surgeries for single, double, and triple arthrodesis was found to be 22 (8.9%), 8 (11.9%), and 15 (12.7%), respectively; and the rate of 30-day readmission was 7 (2.8%), 2 (3%), and 3 (2.5%), respectively. There were no significant differences in the rate of complications (P = .95), hardware removals (P = .32), revision surgeries (P = .47), or readmission (P > .99) between the 3 groups (Table 2). A post hoc power analysis demonstrated this study had an 88% power to detect a 20% difference in complication rate between our 3 groups.

Table 2.

Outcome Metrics for Hindfoot Arthrodesis Patients.

	Single, n (%) (n=248)	Double, n (%) (n=67)	Triple, n (%) (n=118)	P Value
Complication	12 (4.8)	2 (3)	5 (4.2)	.95
Hardware removal	17 (6.9)	3 (4.5)	8 (6.8)	.32
Revision surgery	22 (8.9)	8 (11.9)	15 (12.7)	.47
Readmission	7 (2.8)	2 (3)	3 (2.5)	>.99

In univariate logistic regression analysis, single, double, and triple arthrodesis procedures were not significantly associated with an increase in complication rate (P = .6, .55, .93), hardware removal rate (P = .16, .25, .54), revision surgery rate (P = .78, .54, .85), or 30-day readmission (P = .25, .95, .22) (Table 3).

Table 3.

Unadjusted Univariate Odds Ratio of Complications, Hardware Removal, Revision, and Readmission for Hindfoot Arthrodesis Patients.

	Odds Ratio	95% CI	P Value
Complication
Single	1.3	0.51-3.5	.6
Double	0.63	0.1-2.3	.55
Triple	0.95	0.3-2.5	.93
Hardware removal
Single	1.7	0.83-3.7	.16
Double	0.49	0.11-1.4	.25
Triple	0.78	0.32-1.7	.54
Revision
Single	0.9	0.4-1.9	.78
Double	1.3	0.5-3.2	.54
Triple	0.92	0.38-2.0	.85
Readmission
Single	1.8	0.7-5.1	.25
Double	0.96	0.22-2.9	.95
Triple	0.46	0.11-1.4	.22

In a multivariable logistic regression analysis, a decrease in CCI was found to be an independent predictive factor for an increase in revision surgery rate (OR = 0.46, 95% CI 0.22-0.85, P = .02) when controlling for confounding variables. However, single, double, and triple arthrodesis were not found to be independent predictors of an increase in complication rate (P = .48, .51, .84), hardware removal rate (P = .52, .45, .94), revision surgery rate (P = .44, .27, .97), or 30-day readmission rate (P = .36, .89, .39) when controlling for confounding variables (Table 4) (Appendix Table 1 -3).

Table 4.

Multivariable Logistic Regression Analysis for Revision Surgery in Single, Double, and Triple Arthrodesis.

	Odds Ratio	95% CI	P Value^a
Single arthrodesis	0.72	0.32-1.7	.44
Double arthrodesis	1.8	0.59-4.7	.27
Triple arthrodesis	0.99	0.39-2.3	.97
Male sex	1.5	0.63-3.4	.34
Age ≥65 y	1.1	0.13-7.0	.91
Charlson Comorbidity Index	0.46	0.22-0.85	.02

Boldface indicates statistical significance (P < .05).

Discussion

Hindfoot arthritis and deformity are a common cause of pain, physical limitation, and foot deformity in adults.^16,20,25 Surgical treatment is recommended in patients with significant morbidity associated with these disorders.^16,20,25 Treatment can include a single, double, or triple arthrodesis, depending on the location of the affected joints and other patient-specific factors.^20,25 Although all have been demonstrated to be effective in treating various foot and ankle conditions, there is limited and conflicting evidence regarding the rate of complications and revision surgery rate for these three procedures.^4,9 The results of this study demonstrated no significant difference in the rate of complications, hardware removals, revision surgeries, or 30-day readmissions between single, double, and triple arthrodesis procedures, even when controlling for potential confounding variables. The only significant correlation was between the CCI and the revision surgery rate.

An interesting finding concerned the predictive ability of CCI regarding revision surgery rate. Our study found a decrease in CCI, representing an overall healthier patient, was an independent predictive factor for a higher revision surgery rate in those who had undergone either single, double, or triple arthrodesis procedures. Although not previously identified regarding hindfoot arthrodesis procedures, the current literature is conflicting regarding the effect of an increase in comorbid conditions on rates of revisions in foot and ankle surgery.^{1,11,15,18,22} A potential cause of this finding is related to a central component of the CCI equation: age. A study by Mulligan et al¹⁸ found that older patients were less likely to undergo reoperation following elective ankle and hindfoot reconstruction, with the reasoning being that the risks of reoperation increase with age, and, as such, fewer older patients received reoperation surgeries. This reasoning could potentially explain our findings, although it is worth noting that age ≥65 years was a component of our multivariable analysis and was not found to be significantly associated with an increase in revision surgery rate. Another hypothesis is that younger patients have higher demands and may not accept an inferior result and are more willing to undergo revision surgery. Further study into this result is necessary to fully understand the relationship between CCI and the rate of revision surgery following single, double, or triple hindfoot arthrodesis.

Improvement in outcomes following a surgical procedure can be delayed or inhibited by postoperative complications. Pell et al²¹ found, in those undergoing triple arthrodesis, 11 of 132 had a postoperative complication, whereas Anand et al² demonstrated 4 complications in 18 patients following double arthrodesis. However, these studies did not focus on comparing the complication rate between single, double, and triple arthrodesis for hindfoot arthritis and deformity. The results of the current study demonstrate similar rates of complications among those treated with single, double, or triple arthrodesis, even when controlling for multiple potential confounding variables through a multivariate analysis. The larger cohorts in this study allowed for an 88% power to detect a 20% difference, adding statistical rigor to this study. This information may be valuable for surgeons when counseling a patient regarding the risk of complications for either single, double, or triple arthrodesis procedures.

Currently, there is limited evidence regarding whether there is a difference in the revision surgery rate or hardware removal rate between those treated with single, double, or triple arthrodesis. De Groot et al⁷ found a 17% revision rate in those undergoing triple arthrodesis and Mann et al¹⁷ found a 12.5% revision rate for double arthrodesis for adult-acquired flatfoot, and no current studies have reported an isolated talonavicular arthrodesis revision surgery rate. However, these previous studies did not compare the rate of revision surgery or hardware removal between those treated with single, double, or triple arthrodesis. In the current study, revision surgery rates for single, double, and triple arthrodesis were 12.7%, 11.9%, and 8.9%, which are comparable to the results of previously cited literature. Additionally, there was found to be no significant difference in the rate of revision surgery or hardware removal for those treated with single, double, or triple arthrodesis when controlling for confounding variables. The results of this study concur with the previous literature on the topic and suggest there is a relatively low rate of revision surgery and hardware removal associated with single, double, and triple arthrodesis.

There are several limitations to our study. The nature of a retrospective review prevents us from controlling for variables at the time of surgery, which may limit the validity of our results. Additionally, the data for this study are taken from a database maintained by the South Carolina Revenue and Fiscal Affairs, the state office charged with providing publicly sourced data across all state agencies and state-supported entities. It is worth noting that migration out of the database may occur if patients are treated postoperatively outside of the state of South Carolina. ICD-9, ICD-10, and CPT codes were used to define our study groups and outcomes. As such, improper coding may result in either over- or underestimation of certain disease states, which in turn can limit our ability to generalize these results to a larger population. Additionally, although we controlled for observable variables, including age, sex, race, and comorbidities, there are unobservable factors, such as surgeon experience and preference, or unrecorded variables, such as clinician cluster, which could not be controlled for and may introduce bias into our results. Finally, the database we obtained our data from does not contain radiographic indications for surgery. Despite these limitations, our study is one of the first to conduct a database study to generate the large cohort necessary to directly compare the rates of complications and postoperative outcomes between those who underwent single, double, or triple arthrodesis.

Conclusion

There was no statistically significant difference in the rate of complications, hardware removals, revision surgeries, or 30-day readmissions in those undergoing single, double, or triple arthrodesis for the treatment of hindfoot deformity/arthritis. However, a lower Charlson Comorbidity Index, indicating a healthier patient, did have a significant relationship with a higher rate of revision surgery. Further study including radiographic indications for surgery or the impact of overall health status on revision surgery rates may further elucidate the other components of this relationship.

Supplemental Material

sj-pdf-1-fao-10.1177_24730114241231559 – Supplemental material for Retrospective Review of Complications and Revision Rates Between Isolated Talonavicular vs Talonavicular and Subtalar (Double) Arthrodesis vs Triple Arthrodesis

Supplemental material, sj-pdf-1-fao-10.1177_24730114241231559 for Retrospective Review of Complications and Revision Rates Between Isolated Talonavicular vs Talonavicular and Subtalar (Double) Arthrodesis vs Triple Arthrodesis by Chase Gauthier, Yianni Bakaes, Matthew Martinez, James Hardin, Tyler Gonzalez and J. Benjamin Jackson in Foot & Ankle Orthopaedics

Footnotes

Appendix Table 3.

Multivariable Logistic Regression Analysis for Readmission in Single, Double, and Triple Arthrodesis.

	Odds Ratio	95% CI	P Value
Single arthrodesis	0.91	0.25-4.4	.36
Double arthrodesis	1.1	0.23-3.9	.89
Triple arthrodesis	0.54	0.12-1.8	.39
Male sex	1.1	0.39-3.6	.87
Age ≥65 y	0.48	0.02-4.2	.55
Charlson Comorbidity Index	0.85	0.44-1.4	.57

Appendix 1

Complications and the Corresponding ICD-9 and ICD-10 Codes

Ethical Approval

Ethical approval for this study was obtained from the Prisma Health Institutional Review Board [2042199-1].

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. ICMJE forms for all authors are available online.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Chase Gauthier, MD,

Yianni Bakaes, BS,

Tyler Gonzalez, MD, MBA,

J. Benjamin Jackson III, MD, MBA,

References

Althoff

Ramamurti

Vennitti

, et al. Preoperative risk factors for primary metatarsophalangeal arthroplasty revision to MTP arthrodesis for hallux rigidus. Foot Ankle Int. 2022;43(9):1242-1249. doi:10.1177/10711007221094837

Anand

Nunley

DeOrio

JK.

Single-incision medial approach for double arthrodesis of hindfoot in posterior tibialis tendon dysfunction. Foot Ankle Int. 2013;34(3):338-344. doi:10.1177/1071100712468564

Babatunde

Eberth

Felder

, et al. Racial disparities and diagnosis-to-treatment time among patients diagnosed with breast cancer in South Carolina. J Racial Ethn Health Disparities. 2022;9(1):124-134. doi:10.1007/s40615-020-00935-z

Burrus

Werner

Carr

Perumal

Park

JS.

Increased failure rate of modified double arthrodesis compared with triple arthrodesis for rigid pes planovalgus. J Foot Ankle Surg. 2016;55(6):1169-1174. doi:10.1053/j.jfas.2016.07.001

Ceccarini

Rinonapoli

Gambaracci

Bisaccia

Ceccarini

Caraffa

The arthroereisis procedure in adult flexible flatfoot grade IIA due to insufficiency of posterior tibial tendon. Foot Ankle Surg. 2018;24(4):359-364. doi:10.1016/j.fas.2017.04.003

Chakraborty

Axon

Brittingham

Lyons

Cole

Turley

CB.

Differences in hospital readmission risk across all payer groups in South Carolina. Health Serv Res. 2017;52(3):1040-1060. doi:10.1111/1475-6773.12579

De Groot

Reijman

Luning

HAF

Verhaar

JAN.

Long-term results after a triple arthrodesis of the hindfoot: function and satisfaction in 36 patients. Int Orthop. 2008;32(2):237-241. doi:10.1007/s00264-006-0295-4

DeVries

Scharer

Hindfoot deformity corrected with double versus triple arthrodesis: radiographic comparison. J Foot Ankle Surg. 2015;54(3):424-427. doi:10.1053/j.jfas.2014.09.020

Fadle

El-Adly

Attia

Mohamed

Mohamadean

Osman

AE.

Double versus triple arthrodesis for adult-acquired flatfoot deformity due to stage III posterior tibial tendon insufficiency: a prospective comparative study of two cohorts. Int Orthop. 2021;45(9):2219-2229. doi:10.1007/s00264-021-05041-1

10.

Fischer

Oepping

Altmeppen

, et al. Adult-acquired flatfoot deformity: combined talonavicular arthrodesis and calcaneal displacement osteotomy versus double arthrodesis. J Clin Med. 2022;11(3):840. doi:10.3390/jcm11030840

11.

Gaugler

Krähenbühl

Barg

, et al. Effect of age on outcome and revision in total ankle arthroplasty. Bone Joint J. 2020;102-B(7):925-932. doi:10.1302/0301-620X.102B7.BJJ-2019-1263.R2

12.

Goss

Stauch

Lewcun

, et al. Natural history of 321 flatfoot reconstructions in adult acquired flatfoot deformity over a 14-year period. Foot Ankle Spec. 2021;14(3):226-231. doi:10.1177/1938640020912859

13.

Gross

Lewis

Adams

Easley

DeOrio

Nunley

JA.

Secondary arthrodesis after total ankle arthroplasty. Foot Ankle Int. 2016;37(7):709-714. doi:10.1177/1071100716641729

14.

Howell

Vena

Cai

, et al. Temporal trends in cardiovascular hospital discharges following a mass chlorine exposure event in Graniteville, South Carolina. Front Public Health. 2019;7:112. doi:10.3389/fpubh.2019.00112

15.

Kaiser

Häller

Uçkay

, et al. Revision after total transmetatarsal amputation. J Foot Ankle Surg. 2019;58(6):1171-1176. doi:10.1053/j.jfas.2019.03.015

16.

Kurup

Vasukutty

Midfoot arthritis—current concepts review. J Clin Orthop Trauma. 2020;11(3):399-405. doi:10.1016/j.jcot.2020.03.002

17.

Mann

Beaman

DN.

Double arthrodesis in the adult. Clin Orthop. 1999;365:74-80. doi:10.1097/00003086-199908000-00010

18.

Mulligan

McCarthy

Grear

Richardson

Ishikawa

Murphy

GA.

Preoperative risk factors for complications in elective ankle and hindfoot reconstruction. Foot Ankle Spec. 2018;11(1):54-60. doi:10.1177/1938640017706155

19.

Olatosi

Zhang

Weissman

Haider

Using big data analytics to improve HIV medical care utilisation in South Carolina: a study protocol. BMJ Open. 2019;9(7):e027688. doi:10.1136/bmjopen-2018-027688

20.

Patel

Rao

Nawoczenski

Flemister

DiGiovanni

Baumhauer

JF.

Midfoot arthritis. Am Acad Orthop Surg. 2010;18(7):417-425. doi:10.5435/00124635-201007000-00004

21.

Pell

Myerson

Schon

LC.

Clinical outcome after primary triple arthrodesis. J Bone Joint Surg Am. 2000;82(1):47-57. doi:10.2106/00004623-200001000-00006

22.

Pitts

Alexander

Washington

, et al. Factors affecting the outcomes of tibiotalocalcaneal fusion. Bone Joint J. 2020;102-B(3):345-351. doi:10.1302/0301-620X.102B3.BJJ-2019-1325.R1

23.

Röhm

Zwicky

Horn Lang

Salentiny

Hintermann

Knupp

Mid- to long-term outcome of 96 corrective hindfoot fusions in 84 patients with rigid flatfoot deformity. Bone Joint J. 2015;97-B(5):668-674. doi:10.1302/0301-620X.97B5.35063

24.

Reb

Larson

Hyer

CF.

Medial double arthrodesis: technique guide and tips. J Foot Ankle Surg. 2018;57(2):364-369. doi:10.1053/j.jfas.2017.10.017

25.

Stephens

Grujic

Post-traumatic hindfoot arthritis. J Orthop Trauma. 2020;34(1):S32-S37. doi:10.1097/BOT.0000000000001695

26.

Trnka

HJ.

Arthrodesen zur Behandlung des rigiden Plattfußes [Arthrodesis for the Treatment of Rigid Flatfoot]. Orthop. 2020;49(11):985-990. doi:10.1007/s00132-020-03994-6

27.

Weinraub

Heilala

MA.

Isolated talonavicular arthrodesis for adult onset flatfoot deformity/posterior tibial tendon dysfunction. Clin Podiatr Med Surg. 2007;24(4):745-752. doi:10.1016/j.cpm.2007.06.004

28.

Witrick

Kalbaugh

Shi

Mayo

Hendricks

Geographic disparities in readmissions for peripheral artery disease in South Carolina. Int J Environ Res Public Health. 2021;19(1):285. doi:10.3390/ijerph19010285

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

2.19 MB