The comprehensive management of dog ear deformities: Principles and techniques

INTRODUCTION

Dog ear deformities occur when the length of a wound’s closure is less than the sides of the incision, leading to tissue redundancy at the wound edges. Although they can sometimes resolve spontaneously in small cases (<8 mm), larger deformities (>8 mm) require surgical correction to achieve optimal cosmetic and functional outcomes. The methods for correction vary based on the defect’s size, location, and surrounding anatomy. In fact, excision with dog ear repair was found to have shorter scars than standard elliptical incisions.¹ This case series aims to illustrate the versatility of dog ear correction techniques through real-world cases, offering insights into the principles guiding their application.

CASE SERIES

Case 2

Midline incision extension technique

A 40-year-old male presented with a longstanding dermoid cyst on the scalp. The lesion was excised through a circular incision, which included a vertical extension to facilitate dissection. Following excision, two dog ears were created at the defect margins. The vertical incision effectively bisected each dog ear, allowing their respective triangular wedges to be excised and sutured in alignment with the original closure line. The final result was a symmetric scar lying along the midline with minimal redundancy [Figure 1].

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Figure 1:

(a) Large dermoid cyst on the occipital scalp. (b) Circular incision on skin with in toto dissection of the dermoid cyst. (c) After suturing the midline, there is a resultant dog ear on both superior and inferior aspect. The inferior dog ear was bisected in its midline. (d) Raising one of the bisected dog ear triangles with the help of an Adson forceps. (e) The dog ear triangle was then draped over the intended line of closure with the help of the forceps and its base is incised. (f) Similar procedure was carried out on the contralateral bisected triangle of dog ear. (g) Resultant defect after excising both triangles of dog ear. (h) Defect sutured with vertical mattress sutures. (i) Resultant scar after 10 days.

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Case 3

M-plasty technique

A 50-year-old female with an ulcerated sebaceous cyst on her back underwent excision through a combination of circular and elliptical incisions. Despite careful planning, a dog ear deformity persisted at one apex. An M-plasty was performed by marking and excising a triangular wedge of tissue, effectively shortening the scar length. The resultant closure produced a Y-shaped scar with improved contour and tension distribution [Figure 2].

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Figure 2:

(a) Large ulcerated sebaceous cyst on the back. (b) Incision taken with ellipse enclosing the punctum and a circular extension to encompass the ulceration. The cyst was dissected in toto, with a resultant T-shaped defect. (c) After suturing, there was dog ear present at two limbs of the T. (d) On the superior pole, extent of dog ear was marked with surgical marker and M drawn with distal extent being 2/3^rd of the total dog ear extent. (e) Incision along the marked line extending from the original incision line. (f) Resultant M-shaped defect post-excision. (g) M-shaped defect sutured with half-buried horizontal mattress suture for the apex and simple interrupted suture for the remaining wound. (h) Scar appearance 3-week post-surgery.

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Case 4

S-plasty and counter-weight technique

A 35-year-old female with a sebaceous cyst on her lower back presented with a post-excisional dog ear over the convexity of the latissimus dorsi. A 21-gauge needle was used to evert the deformity, and a marked incision extended obliquely at 120° to the original closure line. The redundant wedge was excised and sutured along relaxed skin tension lines (RSTL), creating an S-shaped scar that followed the natural curvature of the back [Figure 3].

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Figure 3:

(a) Inflamed sebaceous cyst on the back, with circular marking of the planned incision. Dots on the superior and inferior aspect representing the potential length of the elliptical incision. (b) Post excision of the cyst midline suturing done. A 21-gauge needle was inserted to evert the dog ear. A Point is marked at 2/3^rd of the total distance and at 120° to the original line of closure. (c) An oblique 120° incision joining the marked point with the original incision line. (d) The redundant dog ear triangle draped over the oblique incision line and its base is incised. (e) The defect post-excision of dog ear, obliquely at an angle to the original line of incision. (f) Suturing done with simple interrupted technique. (g) Resultant scar 2-week post-surgery.

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Case 5

Rule of halves

A 30-year-old male with a cavernous hemangioma on the right thenar eminence underwent crescentic excision. Post-excision, the wound’s asymmetry was managed using the rule of halves, wherein sutures were placed progressively at midpoints along the longer and shorter edges. This approach ensured even tension distribution and resulted in a curvilinear scar that followed the natural contour of the thenar fold [Figure 4].

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Figure 4:

(a) Nodular lesion on the thenar eminence. (b) Lesion excised with crescentic skin incision and dissected in toto. (c) First suture is tied taking bites from the midline of the long side and the midline of the short side, respectively. (d) Second suture taken following the same rule, note the oblique line of passage of the suture thread. (e) Defect post-suturing, note the curvilinear appearance of the scar (f) Postoperative appearance of the scar after 3 weeks.

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Case 6

Burrow’s triangle excision

A 28-year-old female with a dermal nevus near her marionette fold underwent punch excision of the lesion. Two triangular darts of tissue, located superiorly and inferiorly, were excised and repositioned to align with the nasolabial fold. The central defect was closed directly, and the triangular excisions spontaneously reduced due to the favorable alignment of closure forces. Healing was excellent, with minimal scarring visible [Figure 5].

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Figure 5:

(a) Baseline dermal nevus present on the angle of mouth. (b) The lesion was excised in toto with circular incision. (c) Burow’s triangle of excision displaced laterally so as to fall in the nasolabial folds (d) Defect post-suturing (e) Scar at 10-day follow-up.

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Case 7

Three-bite technique

A 35-year-old female presented with a giant cell tumor of the tendon sheath on the lateral aspect of her right thumb. Following excision, a reclining cone deformity was evident. A suturing technique was employed in which the first bite was taken at the defect base, the second through the dermal tissue laterally, and the third through the dog ear. Tying the sutures effectively flattened the deformity, providing an esthetically pleasing result [Figure 6].

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Figure 6:

(a) Baseline photograph with giant cell tumor present on the lateral aspect of thumb. (b) Lesion was excised with a crescentic incision and suturing was done starting from one side. Note the presence of reclining cone deformity on the longer side. (c) Anchoring bite taken at the floor of the wound. (d) Bite taken intradermally on the shorter side. (e) Bite taken along the curvature of the reclining cone. Tying both ends results in the obliteration of the dog ear.

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Case 8

De-epithelization

A 40-year-old male with a large scalp dermoid cyst underwent excision. Residual tissue redundancy was corrected by deepithelializing the small dog ear and inverting it under the adjacent epidermis. Suturing of the overlying skin resulted in a smooth closure with excellent contour restoration [Figure 7].

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Figure 7:

(a) The standing cone being de-epithelized with a number 11 scalpel blade. (b) De epithelial defect. (c) Bite taken on the floor of the defect to serve as an anchor. (d) Bite taken on the medial de-epithelialized tissue. (e) Bite taken on the lateral edge of the de-epithelized tissue. (f) Sutures tied. (g) Immediate post-suturing photograph. (h) Scar 10-day post-procedure.

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Case 9

V-Y advancement flap

A 45-year-old male presented with a sebaceous cyst on the nape of his neck. After excision, a V-shaped incision on the hair-bearing portion of the defect allowed the creation of an advancement flap. The tissue was advanced and sutured into the defect, resulting in a Y-shaped scar. The closure was tension-free and well-camouflaged [Figure 8].

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Figure 8:

(a) Sebaceous cyst over nape of neck incised dissected and removed in toto with circular skin incision. (b) Linear extension of incision tangentially forming a triangular island of tissue dissected. (c) The triangular piece of tissue is advanced forward and sutured resulting in a Y-shaped defect. (d) The island is secured on all sides with sutures. (e) Immediate post-operative image. (f) Scar at 3-week follow-up.

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Case 10

Right-angled excision

A 32-year-old female presented with a pyogenic granuloma on the base of her fifth proximal phalanx. The lesion was excised circularly, and a crescent-shaped tissue perpendicular to the original wound was excised. Closure resulted in an inverted T-shaped scar, ensuring the functionality of the digit while maintaining esthetic boundaries [Figure 9].

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Figure 9:

(a) Pyogenic granuloma present at the base of the proximal phalanx of the little finger. Lesion was incised and removed in toto with a circular incision. This was extended superiorly in a half-ellipse and another elliptical rim of tissue was dissected perpendicular to it at the proximal flexor crease. (b) Immediate post-operative picture showing sutures holding the flaps of tissue in the form of an inverted T. (c) Scar at the end of 8-week follow-up.

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Case 11

Inverted triangle excision

A 40-year-old male with a parietal scalp dermoid cyst underwent circular excision. On the one side, an inverted triangular wedge was removed, and closure was achieved using a half-buried horizontal mattress suture. The method reduced scar length and maintained alignment with surrounding hairlines [Figure 10].

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Figure 10:

(a) Standing cone deformity on the superior aspect of wound closure line. (b) An inverted triangular wedge of tissue was incised and dissected, encompassing the dog ear. (c-f) Half-buried horizontal mattress suture, with the half-buried component in the midpoint of the base of the inverted triangle. (g) Immediate post-operative picture with a final “T”-shaped line of closure. (h) Scar 10-day post-procedure.

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Case 12

Comet tail flap

A 60-year-old male presented with an infected sebaceous cyst on his back. Following excision and resolution of inflammation, one half of the defect was corrected by excising the dog ear, while the other half was addressed by creating a comet tail flap. A curvilinear incision was rotated to cover the defect, yielding a functional and esthetically acceptable C-shaped scar [Figure 11].

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Figure 11:

(a) Large sebaceous cyst present over the upper back. (b) Lesion excised in toto with a circular skin incision and a combination of blunt and sharp dissection. (c) Surgical marking of planned comet tail flap. (d) Excision of triangular wedge of tissue from one of the sides of the defect. (e) Suturing of the triangular defect results in a one-sided dog ear. An incision is then made along the marked line encompassing half of the dog ear. (f) Resultant dog ear, comet tail flap. (g) The flap is rotated and sutured to the apex of the remaining defect. (h) Scar of the curved Y-shaped comet tail flap 3-week post-procedure.

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DISCUSSION

Dog ear deformities can be categorized into various types-standing cone, lying cone, and inverted cone based on the orientation of excess tissue relative to the original incision line [Figure 12].² A standing cone occurs when the central axis of the dog ear is at a right angle to the skin surface and in line with the original incision. A reclining cone is a half cone with its central axis parallel to the skin surface and the excess tissue lies on the one side of the incision. In an inverted cone, there is a depression with the excess tissue pointing downward into the subcutaneous tissue.

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Figure 12:

Three types of dog ears. (a) Standing cone deformity with the central axis at a right angle to the skin surface. (b) Reclining cone deformity with the central axis parallel to the skin surface. (c) Inverted cone deformity with the apex of excess tissue pointing toward the subcutaneous tissue.

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These deformities arise when the final wound closure line is shorter than the original incised edges, subjecting the excess tissue to rotational forces at the margins. This size discrepancy is particularly pronounced in incisions with apical angles >30° and is exacerbated on convex surfaces due to the natural divergence of dermal fibers beyond suture loops.³ While the body attempts to resolve such deformities through dermal elasticity, age-related changes and actinic damage can reduce this natural capacity, necessitating surgical correction in many cases.⁴

Surgical techniques for dog ear correction

Line-lengthening techniques

Simple bilateral incision extension and midline incision extension techniques are effective for symmetrical wounds that already lie along favorable closure lines, such as RSTLs or boundaries between cosmetic units. These methods produce straight scars without reorienting the incision, making them relatively simple to perform.

Scar-displacement techniques

Techniques such as M-plasty and inverted triangle excision aim to reduce the length of the resultant scar while displacing the incision horizontally. These approaches are particularly useful near free margins or when avoiding crossing cosmetic units is desired.⁶

Convexity-adjustment techniques

The S-plasty technique addresses deformities by shifting the line of closure from a convex to a flat or concave surface, minimizing divergence of dermal fibers between sutures and reducing the prominence of dog ears.⁷

Cosmetic unit and RSTL alignment

Methods like Burrow’s triangle excision strategically position the triangular resected dart to align scars with cosmetic unit boundaries or RSTLs, enhancing the esthetic outcome. Similarly, the right-angled excision technique removes crescentic or elliptical tissue perpendicular to the original defect, ensuring scar placement along anatomical or cosmetic boundaries while preserving functionality.⁸

Tissue-conserving approaches

For smaller dog ears (<15 mm in diameter), the three-bite technique is an effective option, particularly when vascular compromise from full-thickness excision is a concern.⁹ When the base-to-projection ratio does not exceed 3:1, this method avoids significant inverted cone deformities. De-epithelialization is another option for small dog ears located over firm structures like the periosteum, eliminating excess tissue without full excision.¹⁰

Flap-based techniques

The V-Y advancement flap is used when anatomical boundaries or free margins must not be transgressed. By incising and displacing only one side of the standing cone, this technique conserves tissue while repositioning the excess to close the defect. The comet tail flap, a modification of this approach, utilizes the redundant tissue from the dog ear to cover the defect, making it highly versatile.¹¹

An algorithmic approach to manage dog ears is given in Figure 13.²

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Figure 13:

Algorithm for the management of dog ears.

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Dog ears however can be avoided with proper planning of the original incision, by taking an ellipse with apical angles <30° on a flat surface. With such angles, the length-to-breadth ratio is more than 3:1 and the wound edge length is almost equal to the length of the final closure line. A larger apical angle can be more forgiving in concavities as the elastic fibers between two sutures do not diverge as much compared to a convex or flat surface. Young patients without actinic damage have a strong elastic fiber system in their dermis that tends to iron out small dog ears spontaneously. Undermining helps to create a horizontal scar below the surgical defect, which upon contraction flattens the dog ear.

CONCLUSION

The management of dog ear deformities requires a tailored approach, considering the size, location, underlying surface anatomy, and esthetic significance of the defect. By understanding the fundamental principles of reducing apical angles, minimizing rotational forces, and optimizing scar placement, surgeons can achieve optimal functional and cosmetic outcomes. Techniques range from simple incision extensions for symmetrical wounds to advanced flap-based methods for preserving tissue and respecting anatomical boundaries. A stepwise algorithm based on the deformity’s characteristics ensures effective decision-making, allowing surgeons to select the most appropriate technique while minimizing complications and enhancing patient satisfaction.