Introducing A Stepwise Anatomic Framework for Urogenital Reconstruction Derived From Orofacial Plastic Surgery Principles: A Case Report

ABSTRACT

We present a novel labial reconstruction technique in a 48‐year‐old woman with extensive bilateral labial defects caused by steatocystoma multiplex. An anatomy‐guided, stepwise approach integrating scalp and orofacial reconstructive principles enabled successful restoration using a rhomboid mucocutaneous flap, minimizing tissue tension while preserving neurovascular continuity, function, and aesthetics.

1. Introduction

Labial surgery has rapidly gained traction in plastic and reconstructive surgery, yet the functional consequences of postoperative scarring and sensory loss remain significantly underexplored [1]. This gap in knowledge stems largely from insufficient anatomical descriptions of sensory innervation patterns in the surface genitalia. As labiaplasty becomes increasingly prevalent, a comprehensive understanding of clitoral and vulvar sensory innervation is essential to prevent nerve damage and achieve the best possible outcomes. Traditional surgical techniques often neglect the complexities of sensory innervation, underscoring the urgent need for enhanced anatomical knowledge and meticulous surgical planning to minimize complications [2].

A recent meta‐analysis demonstrates that approximately 17.0% of labiaplasty procedures result in postoperative complications, including aesthetic dissatisfaction (primarily asymmetry), wound complications, and requirements for revision surgery [3]. Notably, wound dehiscence represents a particularly prevalent adverse outcome in up to 39.6% of cases [4]. Adopting a surgical framework rooted in the principle of “Replace Like with Like” could reduce complications by optimizing tissue compatibility and preserving function.

Our multidisciplinary team previously described surgical considerations in midline genital structures [1, 2, 5]. We now expand on this by reviewing our approach to superficial reconstruction in hair‐bearing skin. In this case study, we illustrate this approach via a representative case of extensive bilateral vulvar reconstruction using a stepwise surgical algorithm adapted and extended from established principles of reconstructive plastic surgery to address the unique anatomical complexity of this region [6].

2. Case Presentation

2.1. Case History/Examination

A 48‐year‐old woman presented with complaints of progressively worsening vulvar lesions over the preceding year. These lesions, which began as an isolated ‘pimple’, were first noted 10 years earlier, and now encompass the entire region. Without a specific diagnosis, her care had been fragmented, with multiple drainage procedures and rounds of antibiotics during episodic exacerbations that tended to occur with exercise or hot weather.

The examination revealed nodules of varying sizes (2–10 mm) located within the hair‐bearing skin of the labia majora. These lesions were primarily found along the transition zone from hair‐bearing to non‐hairy keratinized epithelium, which is located at the lateral margin of the inner labial fold (Figure 1). Notably absent was the involvement of the mucocutaneous transition of the labia minora. Analogous to the lips in the orofacial region, the medial and lateral surfaces of the labia minora can be likened to the wet and dry vermilion of their anatomical counterpart (Figure 2). Similar to the orofacial region, there is progressive thinning of the epithelium (outer labia) along a curvilinear surface, transitioning into mucosal tissue (inner labia). As evidenced by history and clinical exam, the diagnosis of Steatocystoma Multiplex was rendered and confirmed postoperatively.

FIGURE 1.

Steatocystoma multiplex lesions in the bilateral labia majora, including clusters of yellow‐colored nodules of varying sizes, presented in two (a) unstretched and (b) stretched positions.

FIGURE 2.

Comparative anatomy of the facial vermilion (a) and labia minora (b), highlighting epithelial thinning and mucosal transition. The medial (mucosal) and lateral (cutaneous) surfaces of the labia minora mirror the wet and dry vermilion of the lips, with analogous tissue gradation.

Steatocystoma Multiplex is a skin disorder affecting the pilosebaceous glands and ducts, characterized by multiple flesh‐colored or yellow nodules within the dermis. Although generally asymptomatic, progressively enlarging cysts can be disfiguring and symptomatic. As with our patient, surgical excision is usually reserved for extensive involvement or esthetically sensitive regions.

Typically, laxity and abundance of subcutaneous tissue in this region obviate concerns about achieving a tension‐free closure. However, higher density and size of the lesions in this case had led to convergence of anatomical spaces that previously delineated right and left from the midline clitoral structure (Figure 1). As such, our surgical approach needed to be modified to avoid trauma while maintaining a tension‐free closure of elliptical defects.

2.2. Description of the Anatomy‐Guided Stepwise Procedure

2.2.1. Preoperative Planning and Neurosensory Landmarks

The neurosensory anatomical landmarks of the female genital region remain incompletely characterized. In this study, we describe a novel methodology based on extrapolation from established neuroanatomical principles in males. Given that the anterior and posterior segments of the scrotum are prominently innervated by two distinct spinal cord branches (lumbar and sacral, respectively), we applied this framework to their female anatomical counterparts—the labia majora—and extended it to other regions of the external genitalia.

Here, we translate those findings into a clinically applicable, anatomy‐guided framework. By integrating external anatomical landmarks with hair‐bearing and non‐hair‐bearing skin patterns, we provide a systematic method for identifying vulvar regions supplied predominantly by lumbar or sacral spinal segments and discuss its application in preoperative planning for urogenital reconstruction.

We propose a practical framework for analyzing the surface anatomy of the genitalia, integrating its neurological and histological structures through segmentation based on simple surface landmarks. This step‐by‐step approach begins with locating the lesions in the anogenital region. Separated by the perineum into an anterior and a posterior segment, the anogenital space consists of the urogenital region anteriorly and the anorectal region posteriorly. In addition to neurovascular interconnectivity between the regions, an anatomical and functional continuity characterizes the relationship between superficial and deeper structures in this area. Bounded superiorly by the mons pubis and inferiorly by the perineum, most of the lesions in our case were confined to the urogenital region (Figure 1). Therefore, this paper focuses on the application of our methodology to address reconstructive challenges in the urogenital region.

Preoperative planning begins by describing the lesions within the operative field using the constituent axes: horizontal (X‐axis) and vertical (Y‐axis). This region can anatomically be bounded by four orthogonally oriented planes—topographically analogous to scalp anatomy—featuring two surgically critical watershed areas: (1) a vertical midline watershed demarcating bilateral neurovascular territories, and (2) a horizontal watershed at the convergence of anterior and posterior soft tissue planes.

When considering optimal outcomes, it is important to take into account both the neurovascular supply and cutaneous characteristics, such as the presence or absence of hair and mucosa. We propose that by drawing imaginary lines across key landmarks in the genital area we can identify regions that share similar neurovascular and surface characteristics.

As shown in Figure 3, one can visualize a grid‐like structure by drawing parallel lines along the anterior–posterior and lateral axes in the genital region. This creates divisions that correspond to the neurovascular, histological, and anatomical features present along the curvilinear surface of the genitalia.

FIGURE 3.

Anatomical segmentation of the urogenital region for lesion localization in Steatocystoma Multiplex. (a) Non‐stretched position: Three horizontal lines (x‐axis) demarcate key borders, with the urethral meatus line dividing the genital triangle into anterior and posterior labial regions. A vertical midline (y‐axis) and paired parallel lines further subdivide each side into central, medial, and lateral segments. Most lesions are localized to the medial segments bilaterally. (b) Stretched position: Lesions were confined to the inner medial segment, specifically the transitional zone between wet and dry skin of the labia majora (not typically visible in the non‐stretched position). This precise localization required a plastic surgery approach to ensure proper tissue alignment during closure post‐resection.

2.2.2. Description of the Lesions Along the Anteroposterior Dimension (X‐Axis)

When positioned in the dorsal lithotomy position, three imaginary horizontal lines define the key anatomical borders of the urogenital region. These lines closely follow the neurovascular patterns of the tissue and help to divide the urogenital region into two distinct segments: anterior and posterior, each with a unique neurovascular supply.

A line drawn through the anterior commissure marks the boundary between the mons pubis and the urogenital region. A second line, parallel to the first, is drawn through the posterior commissure and delineates the posterior border of the urogenital region, separating it from the perineum (Figure 4). Lastly, a line drawn between these two lines at the level of the urethral meatus approximates the transition zone between the “anterior labia” and “posterior labia,” representing a neurovascularly homologous ‘watershed’ area. This transition mirrors the anterior‐to‐posterior scrotal division observed in males.

FIGURE 4.

The posterior commissure of the female genitalia, a subtle but anatomically vital landmark for anogenital segmentation. Unlike its more prominent male counterpart, this structure is often poorly visualized yet crucial for defining the posterior boundary of the anogenital region in our anatomical classification system.

By drawing these three lines, the urogenital region on the surface is divided into two distinct segments: an anterior segment and a posterior segment. The anterior segment receives innervation from both lumbar and sacral branches (genitofemoral and ilioinguinal nerves), while the posterior segment is innervated solely by sacral branches (pudendal nerve). Additionally, the hairline growth patterns of the anterior and posterior segments differ, reflecting the direction of the neurovascular supply (Figure 5). Although not as readily visible, this transition zone features a ‘whirling’ pattern in the hairline, similar to what is observed on the scalp. Similar surgical considerations apply, absent the need for precision in scalp surgeries.

FIGURE 5.

Anatomical division of the female urogenital region with functional correlations. The region is partitioned into anterior and posterior segments at the urethral meatus level, corresponding to distinct innervation patterns: the anterior region receives sensory supply primarily from lumbar spinal nerve branches, while the posterior region is innervated by sacral branches. Hair growth patterns mirror this neural segmentation, demonstrating a convergence zone at the transitional boundary between anterior and posterior segments.

The initial observation along the horizontal axis revealed that the Steatocystoma Multiplex lesions were predominantly along the anterior labia majora, with involvement of the anteroposterior watershed area and lesser involvement of the posterior labia majora (Figure 3). Accordingly, the excision and reconstructive plans need to consider this watershed area (e.g., avoiding the selection of pedicles within the watershed zone).

2.2.3. Description of the Lesions Along the Lateral Dimension (Y‐Axis)

The segmentation of the urogenital region along the y‐axis is guided by the histology of the tissue and the type of epithelium covering its surface. The genitalia proper occupy the central (midline) portion of the urogenital region and include the labia minora and clitoral region. Unlike men, in women, the genital and urinary conduits split in deference to functional mandates of reproduction, giving rise to a notably different structure despite similar embryological origin, which can be inferred, in part, by noting the histological characteristics of overlying ‘skin.’ Accordingly, the clitoris and labia minora (corresponding to the phallic structure in men) are covered by non‐hairy, non‐keratinized epithelium and mucosa. Moving laterally, the labia majora (scrotum in men) comprises keratinized, hair‐bearing epithelium, which gradually merges along the leg crease. An imaginary vertical line drawn along the midline, with corresponding parallel lines on each side, can aid in the identification of ‘similar’ tissues across the spectrum of cutaneous characteristics.

Two parallel lines were drawn on either side of the labia majora: a medial line tangential to the curvature of the medial labial fold (the fold between labia majora and minora) and a lateral line tangential to the curvature of the lateral labial fold (the fold between labia majora and groin). By drawing these lines, the urogenital region can be divided into three segments on each side:

1. Central segment: This segment is composed of non‐keratinized epithelium of variable thickness and mucosal tissues, and is centrally located, genitalia proper. It is primarily innervated by the sacral plexus.

2. Medial segment: The largest of the three segments, consisting of hair‐bearing skin of the labia majora or scrotum. This segment follows a curvilinear trajectory that aligns with the curvature of the leg crease laterally and the genital structures medially. The convergence of these elliptical regions from the right and left sides gives rise to the anterior and posterior commissures, which serve as key landmarks for identifying the anterior and posterior boundaries of the urogenital region. This area receives dual innervation from the lumbar and sacral plexuses.

3. Lateral segment: The smallest of the three, characterized by thinner, sparsely haired skin that transitions into the glabrous skin of the leg crease. Primarily innervated by the lumbar region, this area has a limited role in the medical anatomy of the urogenital region; its main function is to serve as a support structure or anchor for the vertically suspended soft tissues of the genitalia.

The initial observation along the longitudinal axis of our presented case revealed that the lesions were bilateral and medially located, pressing against the inner labial fold along the curvilinear surface of the hair‐bearing skin. This indicated that the excision and reconstruction would primarily involve the hair‐bearing skin. Next, we examined two anatomical landmarks along the longitudinal plane: the inner and outer labial folds. The outer labial fold was unaffected. Initially concerning for involvement, a closer inspection of the inner labial fold showed that the lesions were exclusively confined to the lateral margin of the fold, specifically, the hair‐bearing skin of the labia majora (Figure 3).

We therefore concluded that excision and any reconstruction needed to consider the involvement of both watershed areas in this region. Moreover, the anatomical location of the commissure within the watershed necessitated additional consideration in surgical planning and adaptation of time‐honored principles from the orofacial region.

2.3. Procedure Description

Having described and delineated the anatomy along the respective dimensions, we replaced resected tissues with tissue from the same segment, ensuring a match in hairline growth patterns and, consequently, innervation. We employed a modified pinwheel rotation technique to address the bilateral defect surrounding the outer anterior commissure (Figure 6). In this manner, we could avoid the creation of T incisions in the midline by inadvertent merger of incisions from the right and left sides. Unlike the defect on the right anterior segment (amenable to simple rotation), the left exhibited a larger anterior‐to‐posterior ratio, which informed our tissue selection strategy. By extending the pedicle past the watershed area into the posterior region, we could identify a similar ‘curvilinear pedicle’ while avoiding the watershed area. Moreover, bolstered by a firm grasp of superficial planes, we could reach the solitary nodule on the left without extending the incision.

FIGURE 6.

The surgical markings for the operative planning of the right (a) and left (b) sides were designed to remove the Steatocystoma Multiplex lesions and reconstruct the defects using rhomboid flaps.

A counterbalanced approach to tissue rotation was utilized to minimize secondary tension and traction along the anterior commissure. By rotating tissues counterclockwise on one side and clockwise on the other, we aimed to neutralize static and dynamic tension, such as that generated during activities like leaning forward to sit down, which is unique to this anatomical region. This principle is analogous to pinwheel rotation techniques used in scalp reconstruction, with the added benefit of greater tissue laxity and redundancy in the genital region (Figure 7):

1. Right side: A clockwise rotation (right to left) was confined to the anterior labia majora, remote from the watershed area, at the border of the labia majora and mons.

2. Left side: A counterclockwise rotation (left to right) included tissues from both the anterior and posterior regions, accommodating the larger anterior‐to‐posterior ratio of the defect.

FIGURE 7.

Surgical incisions on the affected area in the right (a) and left (b) sides, following the anatomical landmarks of the genital region, for the rhomboid flap.

2.4. Follow‐Up and Outcomes

The modified pinwheel design balanced tension across the operative field while recruiting adjacent tissue with similar neurovascular characteristics. This approach improved postoperative pain management, functionality, and aesthetic outcomes while minimizing the risk of complications such as seroma and superficial wound dehiscence (Figure 8).

FIGURE 8.

Post‐operation outcomes. (a) View of the vulvar region 6 weeks following surgical resection of the Steatocystoma Multiplex lesions. (b) The white line indicates the suturing line, and the blue line delineates the hair growth pattern.

3. Discussion

While traditional vulvoplasty techniques often fail to account for variations in sensory innervation, our study emphasizes the critical importance of understanding cutaneous nerve distribution patterns by analyzing hairline patterns and incorporating this knowledge into surgical planning. We delineated the urogenital regions innervated by the lumbar and sacral segments and identified their transitional zones. Using this information, we marked the skin to locate the cysts within the lumbar regions and planned a rhomboid flap rotation, moving skin from the adjacent lumbar region to the defect created by cyst excision. This approach involved rotating skin with similar patterns of innervation and blood supply to the defect region, which is associated with better sensory outcomes, reduced scar formation, contracture, and risk of vaginal distortion.

Our proposed framework for classifying the urogenital region in the horizontal plane is based on the neuroanatomy and sensory innervation derived from the spinal plexus [7]. In contrast, the longitudinal classification is guided by the histology of surface tissues, including the epithelial type and hair growth patterns. Notably, we identified two watershed areas along the longitudinal axis on both the left and right sides, typically aligned with the level of the urethral meatus. These areas mark the transition where lumbar innervation begins to supply the anterior segment. Due to their distinct innervation patterns and neurovascular variations, these regions represent surgical danger zones. During vulvar reconstruction, it is critical to avoid suturing tissues from opposite sides of these zones, as demonstrated in our case, where a rhomboid flap was employed to prevent this issue. Additionally, the hairline growth pattern of the labia majora also delineates this watershed area, representing the merging point of tissues with differing hair growth patterns.

During embryonic development, the sensory and autonomic nerve fibers that innervate the skin and hair follicles originate from ectodermal neural crest cells. Therefore, it is expected that the distribution patterns of the hairline in surface tissue are directly associated with their correlated nerve distribution patterns. Consequently, by precisely following hair distribution within the tissues, we can identify and differentiate corresponding innervations and their transitional zones. The use of hairline growth patterns for sensory mapping is a well‐established technique in plastic surgery, particularly in perioperative planning for facial and scalp regions. Prior research has demonstrated the efficacy of examining facial hairline growth patterns to discern skin innervation by the three branches of the trigeminal nerve: ophthalmic, maxillary, and mandibular [8]. For the first time, we emphasize the importance of observing and utilizing hairline growth patterns to understand lumbar and sacral innervations and their transitional zones in the genital region.

It is also noteworthy that while designing the rhomboid flaps, we created shorter, serrated incisions compared to the common approaches used in tissue expansion procedures for other body parts, such as the scalp [9]. In scalp tissue expansion, longer dentate incisions are often made to prevent tension lines and disfigurement [10]. However, the labia majora contains a significantly higher amount of subcutaneous fat compared to the scalp. Understanding the role of subcutaneous adipose tissue in tissue remodeling after expansion procedures [10], and considering the forgiving redundancy of underlying fat tissue in the vulvar areas, we believe that utilizing these orofacial plastic techniques involves fewer complications and yields better cosmetic outcomes compared to orofacial reconstructive procedures. This underscores the ease and utility of these techniques in the context of genital reconstructive surgeries, which should be strongly considered in light of the rising prevalence of such surgeries worldwide. Furthermore, it is pertinent to acknowledge that reconstructive procedures involving the vulvar regions present distinctive challenges compared to orofacial reconstructive surgeries, given the multifaceted functions of the vulva and the necessity for a broad range of hip motion.

Although this study presents a novel, practical, stepwise framework for applying established principles of orofacial plastic surgery to genital reconstruction, several limitations should be acknowledged. The proposed framework is preliminary and is based on a single case report. Its application requires advanced knowledge of regional anatomy and reconstructive plastic surgery, as well as careful adaptation to the individual patient's anatomy and the specific characteristics of the normal or diseased vulva. Accordingly, this framework should not be considered a clinical guideline or universally applicable protocol at this stage. Rather, it represents the experience and knowledge of an expert multidisciplinary team and provides a foundation for future studies aimed at developing and validating a comprehensive framework for broader application in routine clinical practice.

Our case study highlights that despite extensive tissue excision, precise preoperative planning based on skin innervation patterns and the utilization of a standard plastic surgery flap can not only achieve optimal cosmetic outcomes and preserve neurosensation but also maintain functionality and range of motion of associated articulations. This underscores the potential of these techniques as an advanced management approach for genital reconstructive surgeries, promising superior aesthetic, sensory, and functional outcomes.

Author Contributions

Lynn Damitz: investigation, methodology, writing – review and editing, supervision. Mohammadamin Parsaei: data curation, writing – original draft, project administration, visualization. Denniz Zolnoun: conceptualization, investigation, funding acquisition, methodology, validation, resources, supervision, writing – review and editing.

Funding

This work, in part, was supported by an NIH mentored career development award (K23HD053631), ZenNovid Foundation Inc. 501(c)(3), and two other NIH grants (NS045685 and HD053631).

Ethics Statement

We strictly adhered to the principles of the Declaration of Helsinki throughout the whole study process. Also, this project was approved by the IRB and the Office of Human Research Ethics of The University of North Carolina at Chapel Hill.

Consent

Written and formal consent for data publication was obtained from the patient.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The authors have nothing to report.