Preliminary Comparative Study of λ-shaped Technique for Treating Infectious Classic Preauricular Sinus

Abstract

Background:

Treatment of infected preauricular sinuses presents a challenge in balancing complete eradication and cosmetic outcomes.

Methods:

A retrospective analysis was conducted on pediatric patients treated between January 2016 and January 2023. Patients were divided into the λ group (n = 186) and the parallel group (n = 78) based on surgical technique. Outcomes included granulation width, surgery time, infection rate, scar score, recurrence rate, and tragus displacement.

Results:

The λ group showed significantly larger granulation width (0.59 ± 0.30 versus 0.51 ± 0.05 cm, P < 0.05), and shorter surgery time (47.26 ± 14.56 versus 51.15 ± 13.55 minutes, P < 0.05). No significant differences were found in scar scores (0.09 ± 0.51 versus 0.09 ± 0.33). The tragus displacement rate was significantly lower in the λ Group (2.15% versus 7.69%, P < 0.05). The overall recurrence rate was 0.38%, and the overall tragus displacement rate was 3.78%.

Conclusions:

Both the λ-shaped technique and the parallel technique are suitable for treating infected preauricular sinuses and have yielded excellent therapeutic and cosmetic outcomes. The λ-shaped technique effectively manages larger infectious lesions and reduces tragus displacement without increasing complication rates.

Takeaways.

Question: How can infected preauricular sinuses in children be effectively treated to achieve both complete eradication and optimal cosmetic outcomes?

Findings: The λ-shaped technique significantly reduced tragus displacement and shortened surgery time compared to the parallel technique, while achieving comparable scar scores and a very low overall recurrence rate (0.38%).

Meaning: The λ-shaped technique is a safe and effective surgical approach for infected preauricular sinuses in children, offering better cosmetic protection of the tragus without compromising eradication outcomes.

INTRODUCTION

Preauricular sinus (PAS) is one of the most common congenital ear abnormalities, with an incidence of 1%–2%.¹ Based on anatomical location, PAS can be classified into classic and variant types.^2,3 The classic type predominates (93.2%), whereas variant types are relatively rare (6.8%).³ Asymptomatic cases require no intervention.⁴ Infection-induced rupture of the sinus allows infectious squamous debris to infiltrate the subcutaneous fat layer, triggering severe chronic inflammation.⁵ Although en bloc resection of the abscess wall and overlying skin can address this inflammatory response, it creates substantial tissue defects often requiring local flap reconstruction with suboptimal aesthetic outcomes. Our department has adopted the λ-shaped technique to treat classic PAS with massive infectious foci, achieving satisfactory results in both radical treatment and cosmetic preservation. The details are reported as follows.

MATERIALS AND METHODS

Clinical Data

A retrospective study was conducted on pediatric patients with infectious classic PASs treated between January 2016 and January 2023. Participants were divided into the λ group and the parallel group based on surgical technique. The following parameters were compared between the 2 groups: granulation tissue width (cm), surgery time (minutes), postoperative incision infection rate (%), scar score, recurrence rate (%), and tragus displacement rate (%).

Inclusion Criteria

1. Diagnosis of classic PAS^2,3 (Fig. 1);

2. Infectious PAS with persistent infected tissue after antibiotic therapy (Fig. 1);

3. Surgical treatment with either the λ-shaped technique or parallel technique.

Fig. 1.

A case of classic preauricular sinus anterior to the helical crus, with infected tissue anteroinferior to the tract.

Exclusion Criteria

1. Variant types of PAS;

2. Classic PAS treated with other surgical techniques.

Surgical Technique

All procedures were performed under general anesthesia. Local infiltration anesthesia was achieved using 10 mL of 1% lidocaine with epinephrine (1:50,000) injected around the preauricular notch, sinus orifice, and peripheral infected tissue.

λ-shaped Technique:

A spindle-shaped incision was made around the sinus orifice, extending superiorly to the postauricular sulcus and inferiorly to the preauricular notch. A second spindle-shaped incision was made along the periphery of the infected tissue, extending upward along the hairline to meet the first incision in the postauricular sulcus. Notably, the classic PAS is typically adherent to the crus of helix. Following excision of the sinus tract and granulation tissue, a ∧-shaped wound was created, with the intervening healthy skin forming a ∧-shaped flap. The resulting skin defect was initially reduced by suturing the superficial temporal fascia with 5-0 absorbable sutures. The remaining defect was then repaired through advancement and transformation of the ∧-shaped flap. The final suture line assumed a λ shape, hence the designation “λ-shaped technique” (Fig. 2).

Fig. 2.

λ-shaped technique. A, Spindle incisions (sinus orifice + infected lesion) are connected at the postauricular sulcus, with anterior edge near the hairline. B, The flap is elevated, infected tissue is resected to the superficial temporal fascia; the tract is excised to helical crus with partial cartilage, the flap is retracted for exposure. C, The suture line transforms from ∧ to λ, hence the name “λ-shaped technique.” D, One-year postoperative: scar with no hyperplasia, elevation, or pigmentation (score 0).

Parallel Technique

Two longitudinal spindle-shaped incisions were made along the sinus tract and the infected tissue, respectively. The flaps were elevated to expose the surgical field, and the infected tissue was dissected toward the crus of helix along the plane of the superficial temporal fascia. Upon reaching the crus of helix, the sinus tract and the perichondrium of the crus were completely excised. The resulting skin defect was initially reduced by suturing the superficial temporal fascia with 5-0 absorbable sutures to narrow the wound width. The remaining defect was then repaired using the intervening healthy skin. The final suture line assumes a near-parallel configuration, hence designating this method as the “parallel technique” (Fig. 3).

Fig. 3.

Parallel technique. A, Parallel spindle incisions along the sinus tract and infected tissue created dual longitudinal surgical accesses. B, The flap is elevated, infected tissue is dissected along the superficial temporal fascia to the helical crus, with tract and perichondrium excised. C, Near-parallel sutured incision (eponymous); at 1 week, no infection but the tragus is anteriorly displaced vs preoperative. D, One-year postoperative: suture absorption caused scar widening to 1.5 mm, with no hyperplasia, elevation, or pigmentation (score 0).

Patients received a 7-day course of oral cefprozil postoperatively. Follow-up was conducted at 3 days to assess for incision infection, and sutures were removed at 7 days. If tension-reducing sutures were placed, these were removed at 14 days.

Postoperative Follow-up

Postoperative follow-up within 2 weeks assessed incision infection and tragus displacement (Fig. 4) after suture removal. Tragus displacement refers to the anterior tilting of the tragus and resultant exposure of the external auditory canal caused by plicated suture of the superficial temporal fascia performed to reduce wound width. From 6 months to 1 year postsurgery, scar characteristics, including vascularity, pigmentation, pliability, and height, were evaluated using the Vancouver Scar Scale (Table 1).^6,7 Recurrence was monitored at 2 years postoperatively.

Fig. 4.

Tragus displacement. A, Preoperative: sinus orifice anterior to the helical crus, granulation tissue (2.0 × 2.5 cm) anteroinferior, and tragus obscuring ear canal. B, Post-excision: the flap is preserved, defect 3.0 × 3.5 cm. C, Post-plication: the tragus is displaced anteriorly, exposing the ear canal. D, After excision, fascia plication reduces defect width; however, tension causes anterior tragus tilting and ear canal exposure, with the λ-shaped technique still producing a scar (score 3).

Table 1.

The Vancouver Scar Scale

	Scar Characteristic	Score
Vascularity	Normal	0
	Pink	1
	Red	2
	Purple	3
Pigmentation	Normal	0
	Hypopigmentation	1
	Hyperpigmentation	2
Pliability	Normal	0
	Supple	1
	Yielding	2
	Firm	3
	Ropes	4
	Contracture	5
Height	Flat	0
	<2 mm	1
	2–5 mm	2
	>5 mm	3
Total score		13

Statistical Methods

Data processing and statistical analysis were performed using SPSS 26.0 software. Measurement data are presented as mean ± SD (x ± s). Categorical data were analyzed using the chi-square test. A P < 0.05 was considered statistically significant.

This retrospective study was approved by the institutional review board of the Children’s Hospital of Soochow University. Given the retrospective nature of the study and the use of de-identified patient data, the requirement for informed consent was waived by the institutional review board. The study was conducted in accordance with the ethical standards of the Declaration of Helsinki and its later amendments.

RESULTS

From January 2016 to January 2023, a total of 359 patients with PAS were admitted, among whom 264 met the inclusion criteria. The λ Group comprised 186 patients (82 men and 104 women), whereas the parallel group included 78 patients (34 men and 44 women). No statistically significant difference was observed between the groups (P > 0.05). In the λ group, 84 cases involved left-ear sinuses and 102 cases right-ear sinuses; in the parallel group, 36 cases involved left-ear sinuses and 42 cases right-ear sinuses, with no statistically significant difference (P > 0.05). The age range in the λ group was 12 months to 13 years 7 months (mean 4.34 ± 3.99 y), and in the parallel group, 11 months to 15 years 3 months (mean 4.59 ± 3.78 y), with no statistically significant difference (P > 0.05) (Table 2).

Table 2.

Comparison of Data Between the λ Group and the Parallel Group

Group	Number	Male/Female	Left/Right	Age (y)	Infection Duration (mo)	Granulation Width(cm)	Surgery Time (min)	Postoperative Incision Infection Rate (100%)	Scar Score	Recurrence Rate (100%)	Tragus Displacement Rate (100%)
λ Group	186	82/104	84/102	4.34 ± 3.99	8.32 ± 10.23	0.59 ± 0.30	47.26 ± 14.56	3.23 (6/186)	0.09 ± 0.51	0 (0/186)	2.15 (4/186)
Parallel Group	78	34/44	36/42	4.59 ± 3.78	5.13 ± 4.13	0.51 ± 0.05	51.15 ± 13.55	2.56 (2/78)	0.09 ± 0.33	1.28 (1/78)	7.69 (6/78)
t value/χ2 value		0.005	0.022	−0.463	2.665	2.221	−2.084	0.082	−0.738	0.031	4.631
P		0.941	0.893	0.644	0.008	0.027	0.039	0.775	0.979	0.122	0.031

^*P < 0.05 indicates statistical significance.

The infection duration ranged from 1 to 48 months (mean 8.32 ± 10.23 mo) in the λ group and 1 to 12 months (mean 5.13 ± 4.13 mo) in the parallel group, showing a statistically significant difference (P < 0.05). Granulation tissue width ranged from 0.5 to 2 cm (mean 0.59 ± 0.30 cm) in the λ group and 0.3 to 0.8 cm (mean 0.51 ± 0.05 cm) in the parallel group, with a significant difference (P < 0.05). Surgery time ranged from 15 to 110 minutes (mean 47.26 ± 14.56 min) in the λ group and 10 to 75 minutes (mean 51.15 ± 13.55 min) in the parallel group, demonstrating a significant difference (P < 0.05) (Table 2).

The postoperative incision infection rate was 3.23% (6/186) in the λ group and 2.56% (2/78) in the parallel group, with no significant difference (P > 0.05). Scar scores evaluated at 6 months to 1 year postoperatively (Figs. 2–4) were 0.09 ± 0.51 in the λ group and 0.09 ± 0.33 in the parallel group, showing no significant difference (P > 0.05). The overall surgical recurrence rate was 0.38%. The recurrence rate was 0% in the λ group and 1.28% in the parallel group, with no significant difference (P > 0.05). The overall tragus displacement rate was 3.78%. Tragus displacement occurred at rates of 2.15% in the λ group and 7.69% in the parallel group, indicating a statistically significant difference (P < 0.05) (Table 2).

DISCUSSION

Typically, acutely infected PASs are initially treated with a course of antibiotics to control inflammation. If an abscess is present, incision and drainage is performed. Notably, the drainage incision should be placed as close as possible to the sinus orifice, as a remotely placed drainage site may necessitate a dual-incision approach in the future to simultaneously address both the sinus tract and the resulting scar or granulation tissue. The persistent irritation from squamous epithelial secretions within the sinus tract promotes granulation tissue formation and leads to chronic infection.

In pediatric populations, particularly infants and young children, medical phobia is common, making it challenging to achieve cooperation with treatments such as antibiotic therapy, abscess drainage, and repeated dressing changes. Forcibly administering these treatments may cause psychological trauma to patients, parents, and even healthcare providers.

Complete surgical excision of the sinus tract remains the only definitive cure, with the optimal timing being 1 month after infection resolution.⁸ Our results show that the infection duration was 8.32 months in the λ group compared to 5.13 months in the parallel group. The process of infection control is often prolonged and distressing for pediatric patients. Complete infection control is not always absolutely necessary, as not all infections can be effectively managed. With accumulating experience and technical advancements, more surgeons are adopting and performing infected PAS excision during the active infection phase.⁹

Various surgical techniques exist for PASs, with the choice depending on the sinus location, infection status, presence of associated infectious foci, and the size of any infected tissue.^4,10 However, inadequate experience and failure to identify the PAS may lead to insufficient treatment with recurrence, or even unnecessary surgical procedures.⁵

The parallel technique, utilizing dual incisions to simultaneously excise the sinus tract and infected tissue, is a well-established and widely adopted approach¹¹ that effectively controls recurrence rates. In our practice, this technique enabled concurrent removal of both the sinus and infected foci. The resulting skin defect after resection of infected tissue was addressed by suturing the superficial temporal fascia to reduce tension and minimize the defect size, followed by repair of the residual defect through advancement of the intervening skin. Our results demonstrate that the parallel technique achieved a recurrence rate of 1.28%, superior to the previously reported 3.5%.⁴

However, the parallel technique has limited flap mobility and is suitable only for granulation tissue widths <0.8 cm. Larger defects may lead to skin puckering and anterior tragus displacement, compromising cosmetic outcomes. To address this limitation, we modified the parallel technique by extending the incision superiorly to the postauricular sulcus, creating a more mobile λ-shaped flap.

The λ-shaped technique offers several advantages:

1. Exceptionally low recurrence rate: Resection of inflammatory tissue and partial adjacent crus of helix cartilage significantly reduces recurrence.^12,13 The technique provides excellent surgical exposure, allowing precise dissection along the superficial temporal fascia plane toward the crus of helix, with excision of the sinus tract and perichondrium. No recurrence was observed during follow-up.

2. Capability to manage larger infections: The λ-shaped flap exhibits superior transverse and longitudinal mobility, enabling repair of defects up to 2 cm wide.

3. Reduced operative time: In the λ-shaped group, the granulation tissue was wider, which theoretically would require more time for debridement of granulation tissue and the sinus tract, tension-reducing suture of the superficial temporal fascia, and wound repair. However, the preliminary study paradoxically revealed that the operative time in the λ-shaped group was shorter than that in the parallel group. We preliminarily attribute this result to the improved surgical exposure. The λ-shaped technique involves dissection along the subcutaneous tissue and flap elevation, providing the surgeon with a better surgical field and more precise identification of the sinus tract, granulation tissue, and healthy tissue. In contrast, the parallel technique requires the creation of a subcutaneous tunnel, which necessitates flap elevation and even undermining of the subcutaneous tissue. The suboptimal surgical field affects the surgeon’s confidence and requires more time to distinguish different tissues. We preliminarily conclude that the shorter operative time in the λ-shaped group compared to the parallel group is attributable to its better exposure and facilitated manipulation.

4. Lower tragus displacement rate: The wider the infectious focus, the larger the skin defect, and the higher the incidence of tragus displacement. Although suturing the superficial temporal fascia can reduce the extent of the defect, its anterior traction inevitably leads to tragus displacement. The λ-shaped group faced greater granulation tissue width and consequently larger tissue defects. Theoretically, this would result in more frequent tragus displacement. However, the preliminary findings paradoxically showed a lower rate of tragus displacement in the λ-shaped group. We believe this is because the λ-shaped flap has greater mobility, allowing for transverse flap advancement and a vertical-to-horizontal closure at the preauricular notch, thereby minimizing this complication to the greatest extent.

5. Superior cosmetic outcomes: The main factors influencing scar scores include wound tension, postoperative infection, incision direction and anatomical location, patient age, and genetic predisposition. Although patients in the λ-shaped group had more severe infections and larger tissue defects, the use of the low-tension λ-shaped flap closure technique resulted in final scar scores comparable to those of the less-severe parallel group. This demonstrates that the λ-shaped technique offers significant cosmetic superiority in the management of complex infected PASs.

6. The λ-shaped technique can serve as an alternative to the parallel technique. In clinical practice, if difficulty in defect closure is encountered with the parallel technique, the procedure can be converted intraoperatively to the λ-shaped technique to complete the operation.

Conversely, the λ-shaped technique has certain limitations: (1) it is exclusively applicable to infected classic PASs; (2) the width and thickness of the flap pedicle are constrained by the infected focus and subdermal sinus tract, potentially compromising blood perfusion. Although no flap necrosis was observed in our follow-up, larger sample sizes are required to validate this outcome; (3) the feasibility of the λ-shaped flap depends on the presence of adequate healthy skin between the sinus orifice and infected tissue. Absence of this anatomical prerequisite precludes the use of this technique, necessitating alternative surgical approaches; and (4) in some patients, significant scarring may still occur due to substantial tension.

CONCLUSIONS

In summary, both the λ-shaped technique and the parallel technique are suitable for treating infected PASs and have yielded excellent therapeutic and cosmetic outcomes. Compared to the parallel technique, the λ-shaped technique demonstrates equivalent postoperative incision infection rates, recurrence rates, and scar scores while enabling management of larger infectious foci, reducing tragus displacement rates.

DISCLOSURE

The authors have no financial interest to declare in relation to the content of this article.

PATIENT CONSENT

The authors attest to obtaining written patient consent for the publication of recognizable patient photographs or other identifiable material, with the understanding that this information may be publicly available.

ACKNOWLEDGMENTS

The authors thank the patients and guardians. Because this study was not funded, parents were required to cover the costs associated with postoperative follow-up, such as transportation. Their excellent cooperation enabled us to obtain high-quality postoperative photographs and reliable recurrence rate statistics. The authors thank them for their great contributions. The creation of this work was completed without the use of any artificial intelligence tools.

ETHICAL APPROVAL

This retrospective study was approved by the institutional review board of Children′s Hospital of Soochow University. Given the retrospective nature of the study and the use of de-identified patient data, the requirement for informed consent was waived by the institutional review board.