National Patterns in Surgical Management of Syndactyly: A Review of 956 Cases

Abstract

Purpose: Being one of the most common congenital hand malformations, syndactyly is repaired by orthopedic, plastic, and fellowship-trained general surgeons. Limited multi-institutional outcomes analyses regarding incidence, timing, and type of repair exist. Methods: All syndactyly cases performed over a 5-year period from 2012-2016 were isolated from the National Surgical Quality Improvement Program Pediatric database. Patient demographics, surgical factors, perioperative outcomes, and risk factors were analyzed using χ², Fisher exact, and t-test analysis. Results: A total of 956 patients who underwent syndactyly repair were identified. Most cases were simple syndactyly with nearly even case distribution among plastic and orthopedic surgeons. Most patients were men and Caucasian. Mean age at the time of surgery was 2.6 years. Most cases were performed as outpatient surgery. Patients of plastic surgeons had significantly more airway abnormalities and shorter operative times. Patients with complex syndactyly had significantly more ventilator dependence, tracheostomy, and comorbidities when compared with those with simple syndactyly. Cases with complex syndactyly also had longer operative times and a higher rate of superficial surgical site infections. Conclusions: Syndactyly repair is a safe procedure with few major or minor reconstructive complications regardless of the surgical specialty or syndactyly type. Patients with complex syndactyly have significantly more preoperative comorbidities with comparable outcomes. orthopedic surgeons have significantly longer operative times than plastic surgeons, likely due to caring for increased number of patients with complex syndactyly.

Introduction

Syndactyly is one of the most common congenital limb malformations representing 20% of all newborn hand defects, with an estimated incidence of 1 in 2000 to 3000 live births.^1-4 Incidence patterns demonstrate a predominance in Caucasians, and prevalence is twice as common in male.⁵ The malformation is heterogeneous with unilateral, bilateral, symmetric, and asymmetric variants.⁴ Syndactyly can present in isolation as 1 of 9 nonsyndromic forms or as part of more than 300 syndromic anomalies.^4,6

Broadly, syndactyly is classified as either simple or complex, and complete or incomplete. Simple syndactyly involves only skin and soft tissue, while the complex type has a component of bone or nail fusion. When syndactyly extends through the length of the digit, it is termed complete syndactyly and incomplete when it does not.⁵

Syndactyly requires surgical intervention, and traditional teaching recommends repair at 12 to 18 months of age.⁵ Delays in treatment can affect hand function in addition to the psychosocial impact on the patient’s life. Simple and complex syndactyly are repaired with skin flaps and/or grafts while complex syndactyly also involves osteotomies.^1,7 Although hand surgeons from orthopedic and plastic surgery treat this patient population, differences in patient acquisition, types of syndactyly, and variations in repair have yet to be elucidated.

Using the American College of Surgeons’ National Surgical Quality Improvement Program Pediatric (NSQIP-P) database, surgical intervention for syndactyly was reviewed using data collected from more than 200 hospitals in the United States.^8-11 Few studies have utilized this database to investigate hand surgery, and none have evaluated syndactyly.^12,13

Because most literature regarding the clinical management of syndactyly is largely case series, this study aims to evaluate syndactyly from a cross-sectional multi-institutional analysis to evaluate practice patterns, patient populations, and outcomes.

Methods and Materials

Data Source and Exclusion Criteria

All data were extracted from the NSQIP-P database between the years 2012 and 2016. The NSQIP-P has risk-adjusted surgical data from patient medical charts from more than 200 hospitals in the United States. These data include more than 200 variables, including demographics, perioperative comorbidities, complications, and outcomes. The NSQIP-P database reports complications within a 30-day perioperative period. Surgical complications do not reflect long-term aesthetic or functional outcomes. Data files for NSQIP-P from the years 2012-2016 were combined and analyzed in one master file using SPSS Version 25 (IBM 2017). This study was completed with institutional review board approval. As NSQIP-P is deidentified, patient consent and Health Insurance Portability and Accountability Act concerns are not applicable.

Cases of syndactyly were identified by having one of the following Current Procedural Terminology (CPT) codes: 26560, 26561, or 26562. Patients were excluded if they did not have a 755 ICD-9 (International Classification of Diseases, Ninth Revision) code or a Q70 ICD-10 (International Classification of Diseases, Tenth Revision) code. Cases with 26560 denoted management using skin flaps only, cases with 26561 included patients who received both flaps and grafts, and cases with 26562 included bone osteotomies. Cases with 26560 or 26561 were classified as simple syndactyly; cases with CPT 26562 were considered complex syndactyly.

Statistical Analysis

Frequency statistics were used to analyze demographics, comorbidities, surgical factors, and outcomes for patients who underwent surgery for syndactyly. Demographics including sex, race, age, and surgical specialty were analyzed.

Patients were then analyzed by surgical specialty. Demographics were compared between plastic and orthopedic surgeons. χ² analysis and Fisher exact tests were used for categorical variables, and Student t tests were used for continuous variables. Patients were then divided by simple and complex syndactyly. χ² analysis, Fisher exact tests, and Student t tests were used to analyze differences between the 2 types.

Results

Population Demographics

In total, 956 cases of syndactyly were identified from 2012-2016 (Figure 1). Demographics were analyzed using basic frequency statistics. Most patients were male (68.8%) and Caucasian (65.4%). The overwhelming majority of cases (92.2%) had outpatient surgery. Most cases had simple syndactyly (66.9%). The average age of patients was 2.6 years (SD = 2.9 years). The mean operative time was 134.4 minutes (Table 1).

Figure 1.

Study population.

Note. NSQIP-P = National Surgical Quality Improvement Program Pediatric; CPT = Current Procedural Terminology; ICD-9/10 = International Classification of Diseases, Ninth Revision/Tenth Revision.

Table 1.

Syndactyly Demographics.

Demographic	%	n (SD)
No. of patients		956
Female	31.2
Race
White	65.4
Black	12.3
Hispanic	16.1
Other	6.1
Surgery setting
Inpatient	7.8
Outpatient	92.2
Surgical specialty
Plastic surgery	48.2
Orthopedic surgery	50.8
Other	1.0
Repair type
Flaps	13.4
Flaps and grafts	66.9
Bone osteotomy	19.7
Age, y		2.6 (2.9)
Total operative time, min		134.4 (66.6)
Length of stay, d		0.3 (1.5)

Surgical Specialty Comparison

Specialties were divided nearly equally with 48.2% of cases performed by plastic surgeons and 50.8% of cases by orthopedic surgeons. There were no differences in sex, race, or surgical setting between the 2 surgeon types (Table 2). However, plastic surgeons had more simple syndactyly cases, while orthopedic surgeons completed more complex syndactyly cases. There were significantly more airway abnormalities in patients of plastic surgeons compared with patients of orthopedic surgeons (P = .012). There were no other significant differences in comorbidities or complications. Syndactyly repair by plastic surgeons had shorter operative times than cases repaired by orthopedic surgery (126.1 vs 141.6 minutes, P < .001). There were no significant differences in length of stay or ages of patients. There were no significant differences in complications or 30-day outcomes between plastic and orthopedic surgeons (Table 3).

Table 2.

Comparison Between Orthopedic Surgery and Plastic Surgery.

Demographic	Plastic surgery	Orthopedic surgery	P value
Total no. of patients	461	486
Female, %	30.4	32.3	.521
Race, %			.112
White	63.8	67.1
Black	11.1	13.8
Asian	4.6	5.3
Other	20.5	13.8
Surgery setting, %			.112
Inpatient	9.1	6.4
Outpatient	90.9	93.6
Repair type, %			.035
Flaps	12.6	14.2
Flaps and grafts	70.7	63.2
Bone osteotomy	16.7	22.6
Comorbidities, %
Ventilator dependence	0.7	0.4	.612
History of asthma	4.3	4.7	.771
Chronic lung disease	1.5	1.9	.691
Oxygen support	0.4	0.2	.532
Tracheostomy	1.5	1.6	.875
Airway abnormalities	4.1	1.4	.012
Gastrointestinal disease	7.2	6.6	.727
Previous cardiac surgery	1.7	1.2	.523
Developmental delay	10.8	9.3	.417
Seizure disorder	1.5	0.6	.175
Cerebral palsy	0.4	0.0	.146
Structural central nervous system abnormality	6.3	3.9	.095
Neuromuscular disorder	2.2	2.9	.486
Intraventricular hemorrhage	0.2	0.6	.342
Steroid use (within 30 d)	0.4	0.0	.146
Open wound	0.0	0.6	.091
Nutritional support	3.0	2.1	.338
Hematologic disorder	0.7	0.8	.757
Inotropic support	0.2	0.4	.594
American Society of Anesthesiologists classification, %			.192
1	52.5	49.2
2	36.9	42.4
3	10.0	8.4
4	0.4	0.0
5	0.2	0.0
Age, y	2.8 (3.2)	2.5 (2.5)	.130
Total operative time, min	126.1 (62.1)	141.6 (68.5)	<.001
Length of stay, d	0.2 (0.5)	0.3 (2.0)	.239

Note. Bold P values represent P<0.05.

Table 3.

Comparison Between Orthopedic Surgery and Plastic Surgery Complication Profiles.

Demographic	Plastic surgery	Orthopedic surgery	P value
Complications, %
In hospital >30 d	0.0	0.0
Death in 30 d	0.0	0.0
Superficial incisional SSI	2.0	1.4	.541
Deep incisional SSI	0.0	0.2	.330
Organ SSI	0.0	0.0
Deep wound dehiscence	0.0	0.0
Pneumonia	0.2	0.0	.304
Unplanned intubation	0.0	0.0
Pulmonary embolism	0.0	0.0
Renal insufficiency	0.0	0.0
Renal failure	0.0	0.0
Urinary tract infection	0.0	0.0
Coma	0.0	0.0
Cerebrovascular accident/stroke	0.0	0.0
Seizure disorder	0.0	0.0
Nerve injury	0.0	0.0
Intraventricular hemorrhage	0.0	0.0
Cardiac arrest	0.0	0.0
Bleeding	0.2	0.0	.304
Flap failure	0.4	0.0	.146
Sepsis	0.0	0.0
Readmission, %	1.3	0.8	.472
Reoperation, %	0.0	0.0

SSI = surgical site infection.

Simple Versus Complex Syndactyly

Simple syndactyly cases predominated, but female had significantly more complex syndactyly than simple syndactyly (37.2% vs 29.7%, P = .045). Complex cases were more commonly performed in an inpatient setting (12.8% vs 6.6%, P = .005). Orthopedic surgeons performed more complex cases compared with plastic surgeons (58.8% vs 49.5%, P = .022).

Compared with simple syndactyly, patients with complex syndactyly had significantly greater preoperative ventilator dependence (2.1% vs 0.1%, P = .001), tracheostomy rate (3.6% vs 1.2%, P = .046), gastrointestinal disease (12.2% vs 5.5%, P = .001), developmental delay (16.5% vs 8.3%, P = .001), structural central nervous system abnormalities (10.1% vs 3.8%, P < .001), steroid use (1.4% vs 0.0%, P = .004), nutritional support (5.9% vs 1.7%, P = .001), and American Society of Anesthesiologists class 3 or higher (14.9% vs 7.8%, P < .001). Complex cases had significantly longer operative times (128.4 vs 152.8 minutes, P < .001) (Table 4).

Table 4.

Simple Versus Complex Syndactyly.

Demographic	Simple	Complex	P value
Total no. of patients	768	188
Female, %	29.7	37.2	.045
Race, %			.406
White	65.2	66.0
Black	16.5	14.4
Asian	5.2	3.7
Other	13.1	15.9
Surgery setting, %			.005
Inpatient	6.6	12.8
Outpatient	93.4	87.2
Surgeon type, %			.022
Plastic surgeon	50.5	41.2
Orthopedic surgeon	49.5	58.8
Repair type, %
Flaps	21.6	3.2	<.001
Flaps and grafts	83.3	12.2	<.001
Bone osteotomy	0.0	100.0	<.001
Comorbidities, %
Ventilator dependence	0.1	2.1	.001
History of asthma	4.6	4.3	.858
Chronic lung disease	2.0	0.5	.173
Oxygen support	0.4	0.0	.391
Tracheostomy	1.2	3.6	.046
Airway abnormalities	2.2	4.8	.052
Gastrointestinal disease	5.5	12.2	.001
Previous cardiac surgery	1.3	2.1	.398
Developmental delay	8.3	16.5	.001
Seizure disorder	0.8	2.1	.104
Cerebral palsy	0.1	0.5	.280
Structural central nervous system abnormality	3.8	10.1	<.001
Neuromuscular disorder	2.2	3.7	.236
Intraventricular hemorrhage	0.5	0.0	.321
Steroid use (within 30 d)	0.0	1.4	.004
Open wound	0.3	0.5	.551
Nutritional support	1.7	5.9	.001
Hematologic disorder	0.7	1.1	.552
Inotropic support	0.3	0.5	.551
American Society of Anesthesiologists classification, %			<.001
1	52.0	45.2
2	40.2	38.3
3	7.8	14.9
4	0.0	1.1
5	0.0	0.0
Age, d	2.8 (3.2)	2.5 (2.5)	.127
Total operative time, min	126.1 (62.2)	141.6 (68.5)	<.001
Length of stay, d	0.2 (0.5)	0.3 (2.0)	.239

Note. Bold P values represent P<0.05.

For complications, complex syndactyly repairs had significantly more superficial surgical site infections (4.3% vs 1.0%, P = .002). Although not statistically significant, complex syndactyly had more than double the 30-day readmission rate of simple syndactyly (Table 5).

Table 5.

Simple Versus Complex Syndactyly Complication Profile.

Demographic	Simple	Complex	P value
Complications, %
In hospital >30 d	0.0	0.0
Death in 30 d	0.0	0.0
Superficial incisional SSI	1.0	4.3	.002
Deep incisional SSI	0.1	0.0	.621
Organ SSI	0.0	0.0
Deep wound dehiscence	0.0	0.0
Pneumonia	0.1	0.0	.621
Unplanned intubation	0.0	0.0
Pulmonary embolism	0.0	0.0
Renal insufficiency	0.0	0.0
Renal failure	0.0	0.0
Urinary tract infection	0.0	0.0
Coma	0.0	0.0
Cerebrovascular accident/stroke	0.0	0.0
Seizure disorder	0.0	0.0
Nerve injury	0.0	0.0
Intraventricular hemorrhage	0.0	0.0
Cardiac arrest	0.0	0.0
Bleeding	0.1	0.0	.621
Flap failure	0.3	0.0	.484
Sepsis	0.0	0.0
Readmission, %	0.8	2.1	.104
Reoperation, %	0.0	0.0

Note. Bold P values represent P<0.05.

SSI = surgical site infection.

Discussion

Syndactyly is the second most common congenital hand malformation.² While described in single-institution retrospective studies, reviewing aggregate national trends offers improved cross-institutional and cross-specialty data.⁷ To our knowledge, this study is the largest to date offering outcomes on 956 syndactyly procedures allowing insights into the current practice trends in syndactyly repair and differences based on syndactyly type and surgical specialty. Previous studies have examined complications in broader classifications of congenital hand deformities, but none have used NSQIP-P to elucidate differences in syndactyly practice patterns based on surgeon or case complexity.⁷ Encouragingly, the demographics of our study population were consistent with previously reported sex and racial distributions for syndactyly with a 2.2:1 male:female ratio and majority Caucasian population.

Although the recommended age for surgery is 12 to 18 months,¹ the mean age in our analysis was 2.6 years. However, most patients underwent surgery between the ages of 1 and 2 years, which is consistent with recommended practice (Figure 2). Our study confirms that syndactyly repair is safe with limited complications regardless of the subtype or specialty.¹⁴

Figure 2.

Age distribution at time of surgery.

Syndactyly in the United States is managed predominantly by fellowship-trained hand surgeons from orthopedic surgery and plastic surgery, some of whom have also completed a hand fellowship. As per the American Board of Medical Specialties database, of the 2019 hand specialists, 72% are orthopedic trained, 18% plastic surgery trained, and 10% general surgery trained.¹⁵ Despite shared guidelines among all hand fellowship trainees from the American Society for Surgery of the Hand, baseline differences in orthopedic and plastic surgery training can result in distinctions in surgical approach and referral patterns.

This study investigated differences in syndactyly practice between orthopedic and plastic surgery. Interestingly, a nearly equal number of surgeries were performed by each of the specialties despite the significantly higher number of orthopedic-trained hand surgeons.¹⁶ Orthopedic surgeons had slightly longer operative times, which may be related to orthopedic surgeons operating on complex syndactyly more frequently. Differences in simple versus complex intervention between the specialties are likely a result of the types of patients referred to the surgeon.

Furthermore, our study identified significantly greater comorbidities among patients with complex syndactyly, which may explain why these cases were more likely to be performed inpatient. Complex syndactyly more commonly occurs in the context of significant syndromic associations such as Apert and Down syndrome.^17,18 The longer operative times for complex syndactyly are consistent with the underlying differences in anatomy. Higher rates of comorbidities and more involved surgeries likely led to the higher rates of surgical site infection among patients with complex syndactyly. However, it was encouraging that complications were largely limited and similar between simple and complex syndactyly procedures.

Limitations of this study are mostly related to the NSQIP-P database. The database lacks more specific variables for analysis, including specific digit involvement and surgery location. Misidentification is also a possibility as a result of the use of CPT and ICD-9/10 codes for our population inclusion criteria. Differences in data collection between the different hospitals of the program is also a confounding possibility. Despite these limitations, the large sample size and well-validated data provided by the NSQIP-P database provide significant power.

Our study characterizes the predominant demographics of the syndactyly patient population and highlights differences in practice patterns between orthopedic and plastic surgeons and between complex and simple syndactyly. These findings help further delineate differences in the surgical management of a congenital abnormality between 2 surgical specialties with clinical overlap.