Abstract
Background
The short-term outcomes of pediatric digit replantation have been derived primarily from single-center/surgeon experience. The purpose of this study was to conduct a nationwide analysis of outcomes and trends of pediatric digit replantation as compared to adult patients.
Methods
Digit replantation patients were identified in the 1999–2011 Healthcare Cost and Utilization Project, Nationwide Inpatient Sample. Outcomes included in-hospital procedure-related and total complications, microvascular revision, amputation, and length of stay (LOS). Univariate and multivariate analyses were performed to compare pediatric and adult patients and to identify independent predictors of outcomes. The annual rate of replantation among pediatric digit amputation patients was evaluated over the study period.
Results
A total of 3,010 patients who underwent digit replantation were identified, including 455 pediatric patients. For all replantations, age ≤18 years was associated with a lower likelihood of suffering a total complication (odds ratio (OR) 0.66, P = 0.006), requiring amputation (OR 0.62, P < 0.001), and experiencing LOS >5 days (OR 0.77, P = 0.019), after adjusting for comorbidity, amputation severity, digit type, number of replantations, and hospital characteristics. Similar associations were observed between patient age and replantation outcomes for single-finger replantations. The rate of pediatric replantation (range 16 to 27 %) remained consistent through the study period (incidence rate ratio 0.98, P = 0.06).
Conclusions
The rate of pediatric replantation has been relatively low, being 27 % at most in a given year. Importantly, short-term outcomes are better in children than for adults, supporting the indication to perform replantation in this age group when the surgeon feels that replantation is feasible and safe.
Keywords: Digit Replantation, Pediatric, Outcomes, Microsurgery
Introduction
Mutilating hand injuries that cause diminished hand function negatively impact the psychological and social aspects of patients’ lives [2, 10, 19]. For patients who suffer from traumatic digit amputation, the generally accepted indications to attempt digit replantation are broader for children compared to adults [21, 22, 30]. In the pediatric population, replantation outcomes may benefit from an increased healing potential and lack of comorbidity [5, 15, 21, 24]. In addition, long-term follow-up studies have suggested good functional outcomes in children [11, 16, 35].
Previous studies examining outcomes of digit replantation have largely focused on adult patients at specialty centers in Asia [27]. For children, outcomes following replantation are not well established. Previously reported short-term rates of success following pediatric replantation have ranged from 63 to 97 % [1, 16–18, 26, 33, 35]. These outcomes are derived largely from single-surgeon or single-institution data and may not generalize at the population level. To date, the largest study examining outcomes following digit replantation in children included 120 patients prior to 1991 [33].
Although the indications for adult replantation have changed gradually over time, the indications have remained consistent and broad for children [31]. Despite this, the rate of digit replantation among pediatric patients in the USA was estimated to be 40 % from 2000 to 2006 [32]. The purposes of the current study were to measure the rate of digit replantation among pediatric patients and to further examine outcomes following pediatric replantation using population-level data. A comparison of nationwide outcomes between children and adults following replantation presents an opportunity to revisit the long-standing age-related indication that digit amputation in a child warrants an attempt at replantation.
Materials and Methods
Data Source and Analytic Cohort
A cross-sectional analysis of the Nationwide Inpatient Sample (NIS) database was performed for years 1999 to 2011 to compare pediatric and adult outcomes and trends of digit replantation. The NIS is a compilation of hospital inpatient data that was developed through the Healthcare Cost and Utilization Project (HCUP), sponsored by the Agency for Healthcare Research and Quality [12]. The NIS represents the largest collection of all-payer inpatient care data in the USA, including over 1,000 hospitals in 45 states and over eight million annual inpatient hospital stays.
The database utilizes the updated International Classification of Diseases, Ninth Revision (ICD-9) diagnosis and Clinical Modification (ICD-9-CM) procedure codes. ICD-9 and ICD-9-CM coding is overseen by the National Center for Health Statistics and Centers for Medicare and Medicaid Services.
For the purpose of this study, two cohorts of patients were identified in the NIS. The first cohort was identified initially through ICD-9-CM procedure codes and used for analysis of outcomes following digit replantation. The second cohort was identified using ICD-9 diagnosis codes and used for trend analysis of the rate of digit replantation at the national level.
For the replantation outcomes cohort, patients undergoing finger replantation (84.22) and thumb replantation (84.21) were identified using ICD-9-CM procedure codes. Patients who underwent thumb replantation, finger replantation, or both procedures with non-missing age data were considered for analysis. Patients with ICD-9 diagnosis codes for congenital deformities were eliminated from the analysis. The sample population was stratified by age ≤18 years or age >18 years.
To analyze the trends of digit replantation, traumatic digit amputation patients were identified using ICD-9 diagnosis codes. This cohort included patients with a diagnosis of traumatic finger amputation (886.0), traumatic finger amputation complicated (886.1), traumatic thumb amputation (885.0), or traumatic thumb amputation complicated (885.1). Again, patients’ records with ICD-9 diagnosis codes for congenital deformities were eliminated from this analysis. To estimate annual national rates of digit replantation, NIS discharge weights were applied to the analytic cohort to scale the sample to national estimates. The NIS discharge weights consider differences in both hospital characteristics and the proportion of annual data contribution per hospital to determine scaling factors [13]. An annual ratio was calculated comparing the number of patients who underwent at least one finger or thumb replantation to all amputation patients for each year. Patients who were taken to the operating room for attempted replantation, but due to more extensive injuries than expected or inability to restore circulation to the amputated digit underwent a completion amputation, were not included in the replantation group.
Outcome and Study Variables
The primary outcomes of this study were procedure-related complications, total complications, microvascular revision, digit amputation (thumb, finger, or both), and length of stay (LOS). Procedure-related complications (i.e., wound dehiscence, wound infection, hemorrhage/hematoma, transfusion, and other procedural complications) and systemic complications (i.e., venous thromboembolic disease, hypotension-related sequelae, cardiovascular, respiratory, urinary, and stroke) were defined using ICD-9 codes and combined to make up total complications. Microvascular revision was defined using ICD-9-CM procedure codes, including vessel suturing, revision of vascular procedure, and repair of vessel.
Following replantation, patients were assessed for digit amputation using ICD-9-CM procedure codes for amputation and disarticulation of finger (84.01), amputation and disarticulation of thumb (84.02), or both. All complications were treated as dichotomous variables (none vs. one or more). Given its non-normal distribution, LOS was defined as a binary outcome, ≤5 or >5 days, based on the median LOS of included patients.
For analysis, replantation type was grouped into four categories: all replantations, single-thumb replantation, single-finger replantation, and multiple-digit replantation. Patient age was defined as pediatric, age ≤18 years, or adult, age >18 years. Other sociodemographic variables included gender, race (white; black; Hispanic; other, which included but was not limited to, Asians, Pacific Islanders, and Native Americans), payer (private insurance, Medicare, Medicaid, self-pay, and other, which included but was not limited to, worker’s compensation, Title V, and other governmental programs), and socioeconomic quartiles based on median household income by zip code (0–25th, 26th–50th, 51st–75th, and 76th–100th percentiles).
Comorbidity was measured using the Deyo modification of the Charlson comorbidity index [3, 8]. The patients who underwent replantation of multiple digits during their hospital course were identified when two or more replantation codes were present. Diagnoses of complicated traumatic amputation of thumb (885.1) or complicated traumatic amputation of finger (886.1) or undergoing multiple digit replantations were used to approximate severity of initial injury. Undergoing multiple digit replantations also was used to adjust for replantation complexity.
Other hospital characteristics were provided by the NIS database. Data regarding hospital teaching status, region, location, and bed size were determined through the American Hospital Association Annual Survey of Hospitals. The criteria for classification as a teaching hospital include having an American Medical Association (AMA)-approved residency program, membership in the Council of Teaching Hospitals (COTH), or having a ratio of full-time equivalent interns and residents to beds of 0.25 or higher [14]. Hospital region (Northeast, Midwest, South, and West) was defined by the US Census Bureau. Hospital location (urban and rural) was classified differently before and after 2004. Prior to 2004, NIS classification of urban or rural location was based upon Metropolitan Statistical Area. Starting in 2004, this classification was determined using Core-Based Statistical Area codes. Hospital bed size was categorized by the NIS according to the number of short-term acute beds in a hospital, adjusting for hospital location.
Statistical Analysis
Univariate analyses of the independent variables by outcomes of interest were performed with Pearson χ2 analyses for categorical variables and independent sample t tests for continuous variables. A modified Poisson regression was used for analysis of trends, measuring changes in rate over time. For the primary outcomes of interest (procedure-related and total complications, microvascular revisions, amputation, and LOS), binary logistic regression models were performed to adjust for independent variables. Covariates were based on clinical significance and statistical significance in the univariate analyses. All statistical tests were two-sided, with significance set a priori at P < 0.05. Statistical analyses were performed using SAS version 9.3 (SAS Institute Inc, Cary, NC, USA). This study was deemed exempt from Institutional Review Board approval at our institution, as the HCUP-NIS is a public database without personal identifying information.
Results
A total of 3,010 patients who underwent digit replantation were identified in the NIS from 1999 to 2011. After applying discharge weights, this sample represented approximately 14,875 digit replantation patients in the USA over the 13-year study period. The analytic cohort was comprised of 455 pediatric patients and 2,555 adult patients. With respect to digit type and number, the cohort included 1,133 thumb replantations and 2,389 finger replantations, with 372 patients who underwent multiple-digit replantations.
Mean patient age for pediatric patients was 9 ± 6 years (mean ± standard deviation, SD) and for adults was 40 ± 14 years (Table 1). In total, less than 1 % of patients were excluded from the study due to missing age information. Pediatric patients were less often male (71 vs. 90 %, P < 0.001) with a lower comorbidity burden (6 vs. 10 %, P < 0.05) than adults. With regard to digit type, a smaller proportion of pediatric patients underwent thumb replantation (23 vs. 40 %, P < 0.001) and multiple-digit replantation (8 vs. 13 %, P < 0.01). A greater proportion of pediatric patients underwent finger replantation (78 vs. 63 %, P < 0.001). Children were less likely to have a diagnosis of complicated traumatic finger amputation (9 vs. 13 %, P < 0.05). With regard to hospital characteristics, pediatric patients were less often treated at large bed-size hospitals (70 vs. 78 %, P < 0.001).
Table 1.
Patient and hospital characteristics by age group, HCUP-NIS 1999–2011
| Characteristic | Total, n (%)c (n = 3,010) | Pediatric, n (%)c (n = 455) | Adult, n (%)c (n = 2,555) | P valued |
|---|---|---|---|---|
| Sociodemographic | ||||
| Age, years (mean ± SD) | 35.8 ± 17.4 | 9.3 ± 6.2 | 40.6 ± 14.2 | |
| Gender | <0.001 | |||
| Male | 2,596 (87.0) | 321 (71.2) | 2,275 (89.8) | |
| Race | <0.001 | |||
| White | 1,407 (61.1) | 222 (63.2) | 1,185 (60.7) | |
| Black | 194 (8.4) | 46 (13.0) | 148 (7.5) | |
| Hispanic | 507 (22.0) | 53 (15.0) | 454 (23.3) | |
| Other | 197 (8.5) | 31 (8.8) | 166 (8.5) | |
| Payer | ||||
| Private insurance | 1,176 (39.2) | 255 (56.0) | 921 (36.1) | |
| Medicare | 126 (4.2) | n/a | 126 (5.0) | |
| Medicaid | 234 (7.8) | 121 (26.6) | 113 (4.4) | |
| Self-pay | 355 (11.8) | 30 (6.6) | 325 (12.8) | |
| Other | 1,114 (37.0) | 49 (10.8) | 1,065 (41.7) | |
| Income quartile | 0.335 | |||
| 0–25th | 553 (19.1) | 88 (19.9) | 465 (19.0) | |
| 26th–50th | 721 (24.9) | 119 (26.9) | 602 (24.5) | |
| 51st–75th | 774 (26.7) | 103 (23.3) | 671 (27.4) | |
| 76th–100th | 847 (29.3) | 132 (29.9) | 715 (29.1) | |
| Clinical | ||||
| Charlson comorbidity | 0.003 | |||
| None | 2,735 (90.8) | 430 (94.5) | 2,305 (90.2) | |
| ≥Low | 275 (9.2) | 25 (5.5) | 250 (9.8) | |
| Replantation type | ||||
| Thumb | 1,133 (37.6) | 105 (23.1) | 1,028 (40.2) | <0.001 |
| Traumatic thumb amputation, complicateda | 149 (13.2) | 17 (15.5) | 132 (12.8) | 0.333 |
| Finger | 1,968 (65.4) | 357 (78.5) | 1,611 (63.1) | <0.001 |
| Traumatic finger amputation, complicatedb | 244 (12.4) | 33 (8.9) | 212 (13.1) | 0.029 |
| Multiple digits | 372 (12.4) | 37 (8.1) | 335 (13.1) | 0.003 |
| Hospital | ||||
| Teaching hospital | 0.128 | |||
| Yes | 2,469 (82.4) | 361 (79.9) | 2,108 (82.8) | |
| Region | 0.069 | |||
| Northeast | 517 (17.2) | 88 (19.3) | 429 (16.8) | |
| Midwest | 633 (21.0) | 108 (23.7) | 525 (20.6) | |
| South | 1,041 (34.6) | 155 (34.1) | 886 (34.6) | |
| West | 819 (27.2) | 104 (22.9) | 715 (28.0) | |
| Location | 0.555 | |||
| Urban | 2,898 (96.7) | 435 (96.2) | 2,463 (96.8) | |
| Rural | 99 (3.3) | 17 (3.8) | 82 (3.2) | |
| Bed size | <0.001 | |||
| Small and medium | 687 (23.0) | 138 (30.5) | 549 (21.6) | |
| Large | 2,310 (77.0) | 314 (69.5) | 1,996 (78.4) | |
CI confidence interval
aAs defined by ICD-9 Diagnosis Code 885.1 (traumatic thumb amputation, complicated)
bAs defined by ICD-9 Diagnosis Code 886.1 (traumatic finger amputation, complicated)
cCases with missing information are excluded. Given in absolute numbers (n) and as percentage of patients in that characteristic group
d P value for statistic comparing pediatric and adult patients for the given characteristic
Unadjusted analysis demonstrated differences in outcomes by age group following all replantations and single-finger replantations (Table 2). For all replantations, children less often suffered a total complication (13 vs. 20 %, P < 0.001), underwent microvascular revision (16 vs. 20 %, P < 0.05), required an amputation (19 vs. 29 %, P < 0.001), and experienced LOS >5 days (31 vs. 40 %, P < 0.001).
Table 2.
Unadjusted outcomes after replantation by age group, HCUP-NIS 1999–2011
| Pediatric (%) | Adult (%) | P value | |
|---|---|---|---|
| All replantations (n = 3,010) | |||
| Complications | |||
| Procedure-related | 8.4 | 11.1 | 0.079 |
| Total | 13.0 | 20.1 | <0.001 |
| Microvascular revision | 15.8 | 19.8 | 0.047 |
| Amputation | 18.5 | 29.1 | <0.001 |
| LOS | |||
| >5 days | 31.4 | 39.9 | <0.001 |
| Single-thumb replantation (n = 1,038) | |||
| Complications | |||
| Procedure-related | 11.5 | 10.8 | 0.850 |
| Total | 18.8 | 18.3 | 0.906 |
| Microvascular revision | 18.8 | 20.3 | 0.722 |
| Amputation | 13.5 | 10.9 | 0.440 |
| LOS | |||
| >5 days | 35.6 | 39.1 | 0.494 |
| Single-finger replantation (n = 1,600) | |||
| Complications | |||
| Procedure-related | 7.5 | 10.1 | 0.150 |
| Total | 9.6 | 19.2 | <0.001 |
| Microvascular revision | 14.0 | 20.2 | 0.011 |
| Amputation | 17.7 | 32.2 | <0.001 |
| LOS | |||
| >5 days | 26.7 | 36.2 | 0.001 |
| Multiple digit replantations (n = 372) | |||
| Complications | |||
| Procedure-related | 8.1 | 15.8 | 0.213 |
| Total | 27.0 | 29.0 | 0.806 |
| Microvascular revision | 24.3 | 17.0 | 0.269 |
| Amputation | 35.1 | 45.1 | 0.248 |
| LOS | |||
| >5 days | 62.2 | 56.4 | 0.503 |
CI confidence interval, LOS length of stay
Similarly, following single-finger replantation, children less frequently suffered a total complication (10 vs. 19 %, P < 0.001), underwent microvascular revision (14 vs. 20 %, P < 0.05), required a finger amputation (18 vs. 32 %, P < 0.001), and experienced LOS >5 days (27 vs. 36 %, P < 0.001). There were no differences for single-thumb replantation and multiple-digit replantation between age groups. No differences were found in procedural complications for all replantation categories between age groups.
In multivariate analysis, patient age ≤18 years was associated with a lower likelihood of suffering a total complication, amputation, and LOS >5 days for all replantations and single-finger replantation, after adjusting for comorbidity, amputation severity, digit type, number of replantations, and hospital characteristics (Tables 3, 4, and 5). In addition, age ≤18 years was associated with a lower likelihood of microvascular revision for single-finger replantation.
Table 3.
Multivariate analysis of independent predictors of total complications
| Variable | All replantations | Single-thumb replantation | Single-finger replantation | Multiple digit replantation | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OR | 95 % CI | P value | OR | 95 % CI | P Value | OR | 95 % CI | P value | OR | 95 % CI | P value | |
| Age ≤18 years | 0.66 | 0.50–0.89 | 0.006 | 1.13 | 0.66–1.96 | 0.650 | 0.50 | 0.33–0.74 | <0.001 | 0.91 | 0.42–2.01 | 0.822 |
| Charlson score ≥ low | 2.41 | 1.84–3.17 | <0.001 | 1.99 | 1.26–3.17 | 0.003 | 3.15 | 2.15–4.61 | <0.001 | 1.73 | 0.81–3.66 | 0.156 |
| Traumatic thumb amputation, complicated | 1.29 | 0.89–1.88 | 0.180 | 1.44 | 0.92–2.24 | 0.112 | ‐ | ‐ | ‐ | 0.93 | 0.35–2.51 | 0.891 |
| Traumatic finger amputation, complicated | 1.18 | 0.86–1.62 | 0.314 | ‐ | ‐ | ‐ | 1.28 | 0.88–1.86 | 0.197 | 0.63 | 0.28–1.41 | 0.259 |
| Multiple digit replantation | 1.78 | 1.38–2.28 | <0.001 | ‐ | ‐ | ‐ | ‐ | ‐ | ‐ | ‐ | ‐ | ‐ |
| Teaching hospital | 1.49 | 1.14–1.95 | 0.004 | 1.15 | 0.72–1.82 | 0.565 | 1.47 | 1.03–2.09 | 0.032 | 5.64 | 1.68–18.98 | 0.005 |
| Large bed size | 1.25 | 0.99–1.58 | 0.061 | 1.21 | 0.81–1.82 | 0.359 | 1.39 | 1.00–1.92 | 0.050 | 0.86 | 0.46–1.60 | 0.626 |
| Hosmer–Lemeshow test | 0.26 | 0.41 | 0.69 | 0.59 | ||||||||
| C-statistic | 0.62 | 0.58 | 0.63 | 0.61 | ||||||||
OR odds ratio, CI confidence interval, LOS length of stay
Table 4.
Multivariate analysis of independent predictors for outcomes of all replantations
| Variable | Procedure-related complications | Microvascular revision | Amputation | LOS >5 days | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OR | 95 % CI | P value | OR | 95 % CI | P value | OR | 95 % CI | P value | OR | 95 % CI | P value | |
| Age ≤18 years | 0.80 | 0.56–1.14 | 0.214 | 0.78 | 0.60–1.03 | 0.080 | 0.62 | 0.48–0.81 | <0.001 | 0.77 | 1.62–0.96 | 0.019 |
| Charlson score ≥ low | 1.17 | 0.80–1.73 | 0.424 | 1.01 | 0.74–1.39 | 0.930 | 1.21 | 0.92–1.60 | 0.170 | 1.29 | 1.00–1.67 | 0.059 |
| Traumatic thumb amputation, complicated | 1.18 | 0.80–1.73 | 0.493 | 0.92 | 0.62–1.38 | 0.692 | 0.90 | 0.63–1.30 | 0.584 | 1.70 | 1.23–2.35 | 0.001 |
| Traumatic finger amputation, complicated | 1.17 | 0.79–1.75 | 0.434 | 1.12 | 0.87–1.65 | 0.267 | 1.75 | 1.33–2.29 | <0.001 | 1.09 | 0.83–1.43 | 0.551 |
| Multiple digit replantation | 1.45 | 1.06–1.98 | 0.021 | 0.82 | 0.62–1.09 | 0.179 | 2.17 | 1.73–2.72 | <0.001 | 2.14 | 1.71–2.68 | <0.001 |
| Teaching hospital | 2.29 | 1.53–3.42 | <0.001 | 1.74 | 1.32–2.29 | <0.001 | 1.76 | 1.38–2.24 | <0.001 | 2.37 | 1.89–2.96 | <0.001 |
| Large bed size | 1.36 | 1.00–1.84 | 0.051 | 1.46 | 1.16–1.85 | 0.002 | 1.25 | 1.02–1.54 | 0.030 | 1.75 | 1.71–2.68 | <0.001 |
| Hosmer–Lemeshow test | 0.24 | 0.33 | 0.17 | 0.22 | ||||||||
| C-statistic | 0.60 | 0.57 | 0.62 | 0.64 | ||||||||
OR odds ratio, CI confidence interval, LOS length of stay
Table 5.
Multivariate analysis of outcomes single-finger replantation
| Variable | Procedure-related complications | Microvascular revision | Amputation | LOS >5 days | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OR | 95 % CI | P value | OR | 95 % CI | P value | OR | 95 % CI | P value | OR | 95 % CI | P value | |
| Age ≤18 years | 0.81 | 0.51–1.29 | 0.376 | 0.66 | 0.47–0.95 | 0.023 | 0.49 | 0.36–0.67 | <0.001 | 0.69 | 0.52–0.91 | 0.009 |
| Charlson score ≥ low | 1.55 | 0.91–2.65 | 0.106 | 1.19 | 0.77–1.84 | 0.435 | 1.22 | 0.83–1.78 | 0.315 | 1.47 | 1.02–2.12 | 0.040 |
| Complicated finger amputation | 1.51 | 0.96–2.37 | 0.072 | 1.14 | 0.79–1.64 | 0.500 | 1.58 | 1.16–2.16 | 0.004 | 1.09 | 0.80–1.49 | 0.588 |
| Teaching hospital | 2.00 | 1.21–3.29 | 0.007 | 2.15 | 1.49–3.12 | <0.001 | 2.16 | 1.59–2.93 | <0.001 | 2.34 | 1.75–3.13 | <0.001 |
| Large bed size | 1.74 | 1.11–2.72 | 0.015 | 1.36 | 1.00–1.85 | 0.053 | 1.30 | 1.00–1.69 | 0.052 | 1.86 | 1.44–2.42 | <0.001 |
| Hosmer–Lemeshow test | 0.91 | 0.62 | 0.52 | 0.64 | ||||||||
| C-statistic | 0.61 | 0.59 | 0.63 | 0.62 | ||||||||
OR odds ratio, CI confidence interval, LOS length of stay
Treatment at a teaching hospital was an independent predictor of procedure-related and total complications, microvascular revision, amputation, and LOS >5 days for all replantations. Similarly, teaching status was an independent predictor of procedure-related and total complications, microvascular revision, amputation, and LOS >5 days for single-finger replantation. Teaching status was an independent predictor of procedure-related complications (not shown, odds ratio (OR) 1.41–7.60, P < 0.01), total complications, and LOS >5 days (OR 1.28–2.79, P < 0.001) for single-thumb replantation and of total complications, amputation (OR 1.20–5.49, P < 0.05), and LOS >5 days (OR 2.50–12.83, P < 0.001) for multiple-digit replantation.
Multiple-digit replantation was a predictor of procedure-related and total complications, amputation, and LOS >5 days for all replantations. Complicated finger amputation was a predictor of amputation for single-finger replantation, and complicated thumb amputation was a predictor of LOS >5 days for all replantations and single-thumb replantations (OR 1.01–2.13, P < 0.05).
National trends showed a consistent annual rate (range 16 to 27 %) of digit replantation for pediatric patients over the study period (incidence rate ratio 0.98, 95 % confidence interval (CI) 0.96–1.00, P > 0.05) (Table 6). In contrast, there was a decrease in the rate (range 12 to 20 %) of digit replantation for adult patients (incidence rate ratio 0.97, 95 % CI 0.95–0.99, P < 0.001).
Table 6.
Annual pediatric traumatic digit amputation and replantation patients, HCUP-NIS 1999–2011
| Year | No. amputation patients | No. replantation patients | Total NIS database (unweighted) | ||
|---|---|---|---|---|---|
| Unweighted | Weighted | Unweighted | Weighted | ||
| 1999 | 212 | 1,064 | 46 | 227 | 7,198,929 |
| 2000 | 223 | 1,086 | 59 | 285 | 7,450,992 |
| 2001 | 173 | 885 | 38 | 197 | 7,452,727 |
| 2002 | 175 | 828 | 32 | 153 | 7,853,982 |
| 2003 | 168 | 810 | 41 | 200 | 7,977,728 |
| 2004 | 211 | 1,015 | 42 | 198 | 8,004,571 |
| 2005 | 152 | 751 | 39 | 193 | 7,995,048 |
| 2006 | 161 | 806 | 32 | 162 | 8,074,825 |
| 2007 | 141 | 687 | 21 | 108 | 8,043,415 |
| 2008 | 113 | 549 | 22 | 107 | 8,158,381 |
| 2009 | 116 | 581 | 25 | 126 | 7,810,762 |
| 2010 | 157 | 793 | 28 | 139 | 7,800,441 |
| 2011 | 100 | 481 | 20 | 96 | 8,023,590 |
| Total | 2,102 | 10,336 | 445 | 2,191 | 86,021,360 |
The number of traumatic digit amputation and replantation patients by year, HCUP-NIS 1999–2011. Weighted estimates represent the number of digit replantation patients multiplied by individual discharge weights in the NIS database. Total NIS database represents the total number of patients, with and without digit replantation, captured in the NIS each year
Discussion
These data suggest improved overall outcomes in children compared with adults following digit replantation, but show a lower than expected rate of pediatric replantation nationwide. Our adjusted analysis shows that pediatric patients are less likely to suffer a complication or require an amputation and more likely to have LOS ≤5 days following all replantations and single-finger replantation. These findings support the longstanding indication to perform digit replantation in children when the surgeon’s clinical assessment is that replantation is feasible and safe.
It has been suggested that digit replantation is less successful in children because of differences in injury type, smaller vessel diameter, and broader indications to attempt replantation in children [18, 20, 34]. However, outcomes following pediatric replantation are not well established, making comparison with the adult population difficult. Previous short-term success rates for pediatric replantation have ranged from 63 to 97 % [1, 16–18, 26, 33, 35]. Using population-level data, we show that replantation in children is associated with improved outcomes compared to adults after adjustment for significant covariates. In addition, our results show higher replantation success rates (82 vs. 70 %) and lower rates of reoperation (16 vs. 29 %) in the pediatric population than previously reported [7, 26].
Patients undergoing multiple-digit replantation more often experienced poor outcomes compared to single-digit replantation patients. Multiple-digit replantation adds complexity to an already challenging clinical scenario. The decision to replant all or select parts, management of different levels of amputation, and the increased number of microvascular anastomoses and potential for replantation failure must all be navigated. We found on adjusted analyses that multiple-digit replantation was an independent predictor of both procedure-related complications and amputation for all replantations. Therefore, considering multiple-digit replantation is important when adjusting for severity of injury.
Our data suggest that patients undergoing single-thumb replantation are more likely to undergo a salvage procedure than an amputation in the event of a take back. Comparatively, however, amputation was more likely than revision following single-finger and multiple-digit replantation. This difference may be due to higher salvage success rates for thumb replantations given differences in vessel diameter [29]. However, salvage success is rarely reported in the existing replantation literature, particularly for thumb replantation. Saies et al. reported reoperation in 21 of 73 digits with a salvage success rate of approximately 10 % [26]. Further research is needed to clarify this discrepancy in revision and amputation rates, as an improved understanding of salvage success rates may help to guide decision making in the setting of a failing replantation.
We found a nationwide annual pediatric digit replantation rate of 16 to 27 % among children admitted following a traumatic amputation. While these rates remained constant over the study period for children, there was a concurrent drop in the rate of replantation for adults. National trends in digit replantation demonstrate that surgeons more often perform digit replantation in children than adults. These trends reflect the broad and unchanging indication to attempt replantation in children. However, rates of pediatric replantation may be lower than expected for a variety of reasons, including loss of the amputated part, multiple levels of injury, prolonged ischemia time, small vessel size, distal avulsion-type injuries, the presence of other life-threatening injuries, or a lack of access to hand surgeons [23, 25]. Patients taken to the operating room with the intention of replantation, but found to have more extensive injuries than expected or in situations where flow cannot be restored and a completion amputation is performed, were not included in the replantation group. Therefore, it is possible that the rate of replantation in this study underestimates the true rate of attempted replantation among children. Future studies examining access to hand surgeons may benefit our understanding of replantation rates in children.
With a goal of improving care coordination and patient outcomes, some authors have suggested the designation of centers for excellence in specialty hand surgery [6, 9, 25]. These centers may benefit from the experience of high-volume surgeons, facilitate more efficient referral patterns, and ultimately improve access to emergency hand surgery. Although the advantages and disadvantages of this designation are beyond the scope of this study, our findings suggest that increasing rates of replantation among children may be worthwhile.
Our estimates for annual rates of pediatric replantation are lower than previously reported [32]. We identified a cohort of digit amputation patients initially through ICD-9 diagnosis codes for traumatic finger or thumb amputation. This method has been used previously [9, 28]. Using an alternative method, Squitieri et al. estimated the rate of pediatric digit replantation at 40 %. Their approach identified amputation patients through fulfillment of two criteria, which included ICD-9 CM procedure codes for replantation in combination with specified major diagnostic categories. Our method may overestimate the rate of traumatic amputations, given that distal avulsion injuries may be captured. However, Squitieri’s approach may overestimate the rate of replantation, given the strict inclusion criteria using ICD-9 CM procedure codes combined with specified major diagnostic categories. It is likely that the true rate of replantation lies somewhere between the two reported rates.
It has been shown that teaching hospitals treat complex amputations and perform replantation more often than nonteaching hospitals [4, 9, 28]. Our data corroborate these findings, as the majority of cases were performed at teaching hospitals. However, teaching status was associated with a higher likelihood of procedure-related and total complications, microvascular revision, amputation, and LOS >5 days for all replantations. This association most likely reflects the greater case complexity seen at teaching institutions and highlights the established association between complexity of replantation or severity of injury and surgical outcomes [27].
Our study benefits from a large sample size and contains data collected from various healthcare settings. As a result, these findings may generalize across diverse patient populations more so than studies with small patient numbers from single clinical settings. However, this study is not without limitations, including those inherent to any administrative database. There is the potential for coding errors at the individual hospitals that may affect the overall results. Multiple-digit replantation and ICD-9 procedure codes for complicated amputation were used to approximate severity of injury; however, information regarding level and type of injury are not available in the NIS. Also, the patient sample was not randomized. As a result, the possibility of unmeasured variables affecting the outcomes, such as smoking history and obesity, cannot be excluded. In addition, this study seeks to differentiate pediatric and adult patients by unmeasured physiologic variables defined arbitrarily using patient age. Therefore, it is possible that these variables are not consistent throughout the pediatric age group or within the adult population.
In this nationwide analysis, we demonstrate that children experience improved short-term outcomes following replantation compared to adults. This suggests that the risk of acute complications and failed replantation should not deter surgeons from attempting replantation in children. These results maintain and support the broad indication for performing digit replantation in children when the surgeon feels that replantation is feasible and safe. Future studies examining timely access to hand surgeons for this important patient group are needed.
Acknowledgments
Conflict of Interest
Nicholas L. Berlin declares that he has no conflicts of interest.
Charles T. Tuggle declares that he has no conflicts of interest.
James G. Thomson declares that he has no conflicts of interest.
Alexander Au declares that he has no conflicts of interest.
Statement of Human and Animal Rights
All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008 (5).
Statement of Informed Consent
This study was deemed exempt from Institutional Review Board approval by our University Human Investigation Committee, as only publicly available, de-identified information was examined. No informed consent for this study was obtained given the nature of the data. HIC Protocol # 1401013202.
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