Scalp Repair Using Flaps and Tissue Expanders

88 Scalp Repair Using Flaps and Tissue Expanders

E. Antonio Mangubat

Summary

Repair of scalp defects poses several surgical and aesthetic challenges. The repair and/or excision of the existing defect is often difficult; however, the cosmesis of the repair is often the most difficult challenge because without careful planning, excision of the defect may leave unsatisfactory cosmesis. Hair transplantation after expanded flap advancement is often useful to camouflage scarring, but care must be taken to preserve vital vasculature. Furthermore, understanding of normal hair anatomy, morphology, and anticipating future hair loss is critical to achieving long-lasting satisfying results. Further challenges include conditions that compromise scalp viability, which make tissue more difficult to treat, such as trauma and residual effects of radiation therapy after cancer treatment. Contemporary techniques in hair restoration surgery allow creation of natural and undetectable results, but these techniques are often unsuitable for repairing large scarred areas of hair loss. By employing older techniques of scalp reduction and tissue expansion, excision of many large scarring defects can be made possible. Combining older methods with modern hair restoration surgery permits the satisfactory treatment of many previously untreatable conditions. This chapter will concentrate on tissue expansion as a significant tool for repairing large scalp defects.

Keywords: tissue expansion tissue expander scalp reconstruction scalp defect scalp flap

Key Points

•The stretching of human skin via tissue expansion occurs as a result of biological and mechanical factors that increase length, volume, and vascular supply.

•Surgical planning is critical and must ensure that the repositioned scalp retains a natural hair direction to avoid an unnatural appearance.

•Hair transplantation after expanded flap advancement should be approached with caution respecting and preserving the major vasculature that may have been altered with expanded flaps.

•Tissue expansion may be repeated if the entire defect cannot be excised.

88.1 Introduction

The most common cause of hair loss is androgenetic alopecia (AGA). Although not a scalp defect, understanding the cosmetic treatment of AGA greatly enhances our ability to treat severe hair loss deformities, allowing us to achieve normal- and natural-appearing results. The successful removal of a large scalp defect that results in a secondary scalp deformity can lead to dissatisfied patients and physicians. The sagittal slot deformity that follows a midline scalp reduction is a classic example of our ability to eliminate bald scalp at the expense of leaving an unnatural result (Fig. 88.1).

Fig. 88.1 Slot deformity resulting from midline scalp reduction. Note divergent hair directions drawing attention to unnatural appearance.

The various deformities and degree of deformity generally determine the treatment choice. The significant developments in hair restoration surgery in the past two decades now yield natural and almost undetectable results. By employing these cosmetic and reconstructive techniques, most scalp deformities can be treated effectively. It is important to understand the anatomy, physiology and cosmetic treatments of AGA and that subject has been treated effectively by other authors in this publication.

This chapter will concentrate on the treatment of large scalp and hair deformities by combining advanced techniques of scalp reduction and tissue expansion, being cognizant of preserving donor vasculature to permit donor harvest for contemporary hair transplantation.

88.2 Hairline Design

Perhaps the most deceptively difficult task in any scalp surgery is planning and executing a normal hairline with natural hair direction. Simple scalp coverage is unsatisfactory if the final result is unnatural. This is true of all scalp procedures including hair transplants, scalp excisions, flap rotation, and movement of expanded scalp flaps. This applies to all areas of the scalp. In general, frontal scalp hair points forward, parietal scalp hair is directed lateral and inferior, and occipital scalp hair is oriented posteriorly and inferiorly.

These subtleties are critical to address in order to avoid unnatural results. Even the untrained eye that does not understand the details of a natural hairline can detect an unnatural result.

88.3 Alopecia Reduction Procedures

Some form of alopecia reduction (AR) is required in virtually all large scalp defect repair. AR techniques allow the surgeon to eliminate unwanted scar. Originally innovated for hair restoration surgery in the 1970s, its popularity waned as hair transplantation techniques improved and our understanding of the natural history of hair loss became more refined. However, the techniques remain valuable tools for scalp repair.

The first AR procedures were simple and involved rapid excision of bald scalp from the central area of hair loss. Limitations of AR were identified and include widening of the bald area (also known as stretch-back),1 slot deformity,² and visible scarring.

The extensive scalp lift is one of the more interesting and effective AR procedures in that the dissection was carried out beyond the limits of the galea aponeurotica marked by the nuchal line, extending inferiorly to the nape of the hairline.³ Extensive scalp lifting permitted a much greater reduction of bald scalp.

88.4 Tissue Expanders

88.4.1 Basic Principles

Tissue expansion is an extraordinary tool for repairing large skin defects, without which most repairs would not be possible. Prior to the introduction of tissue expansion techniques, repair of large defects was crude and ineffective. The original work⁴ on tissue expansion was not considered noteworthy and its significance remained unnoticed for almost 20 years until a young surgeon demonstrated its usefulness in breast reconstruction.⁵ Its simplicity and popularity grew exponentially as an expander manufacturer became involved in producing a commercially viable product.

The technique involves gradual expansion of a balloon prosthesis implanted under the normal skin immediately adjacent to the defect. The expander is incrementally filled with sterile saline through a series of percutaneous injections into a self-sealing fillport. As the balloon increases in size, the tissue compensates by stretching, increasing its length and mass through mechanisms known as mechanical creep (stretching the collagen fibers) and biological creep (stimulating new tissue growth). Mechanical creep is subject to shrinkage when the balloon is removed as the collagen fibers attempt to return to normal resting length. Biological creep, on the other hand, is not stretching in the traditional sense since cellular activation actually increases the amount of tissue present and increases the vascularity and blood flow through the expanded flap. Both properties are critical to successful tissue expansion.

88.4.2 Surgical Planning

Surgical planning is critical to ensure the hair-bearing scalp to be advanced retains natural hair direction. Recall that midline scalp reductions were effective in removing bald scalp but resulted in an obviously unnatural result known as slot deformity.

The use of tissue expansion in cosmetic procedures is limited because of the significant deformity the patient must temporarily endure during the final stages of the process. Reconstructive patients, on the other hand, are more tolerant given the unsightly defects they are trying to repair. The patient and family must be counseled to expect a cosmetic deformity, especially near the end of the expansion process (Fig. 88.2).