Hair Transplantation

Article Author:
Patrick Zito
Article Editor:
Blake Raggio
Updated:
4/14/2020 9:42:39 PM
PubMed Link:
Hair Transplantation

Introduction

Hair loss represents a distressing issue affecting a large portion of the population, including up to 85% of males and 40% of females, and its incidence increases with age for both sexes. Though many causes of hair loss exist, by far the most common etiology is androgenic alopecia (AGA), an androgen-sensitive pattern of hair loss that affects both men and women.[1] Indeed, non-surgical modalities exist which may halt the progression of androgenic alopecia and even help grow new hairs (i.e., minoxidil, finasteride, dutasteride, low-level laser light therapy, platelet-rich plasma, adenosine, ketoconazole) [2][3] Nevertheless, ­recent advancements in surgical hair restoration have made hair transplantation (HT) an increasingly effective, safe, and reliable way for patients distressed by androgenic alopecia to regain a more youthful and natural appearance of their hair.[4]

Anatomy and Physiology

It is essential to understand the relevant anatomy and physiology of hair, and the hair cycle, in order to maximize the outcomes of hair transplantation. Key elements in hair restoration include[5]:

  • Hair follicle – composed of a hair shaft, two surrounding sheaths (inner and outer), and a germinative bulb. The follicle divides into three sections: infundibulum (from the skin surface to the sebaceous gland duct), the isthmus (from the sebaceous duct to the arrector pili muscle insertion), and the inferior segment (from the muscle insertion to the base of the matrix) 
  • Bulb – the deepest segment of the hair follicle which contains the hair matrix (creates the hair shaft), dermal papilla (regulates growth), and melanocytes (produce color).
  • Terminal hair – thick, pigmented hairs at the top of the scalp, beard, axillary, and pubic regions, all of which are androgen-sensitive. The hair elsewhere on the body, including the parietal and occipital scalp, are androgen-independent.
  • Vellus hair – this is fine, short, non-pigmented hairs ("peach fuzz") found on the adult that covers much of the body.
  • Follicular Unit (FU) – a naturally occurring group of hair(s) seen on the scalp consisting of several terminal hairs (usually 1 to 4), a sebaceous gland and duct, and an arrector pili muscle. The collagen band which surrounds the FU is called the perifolliculum.

Scalp Hair Growth cycle[6]:

  • Anagen – the 2- to 6-year active growing phase of the hair follicle. Approximately 90 to 95% of scalp hairs are in anagen at any given time.
  • Catagen – this is the 2- to 3-week involutional phase of the hair follicle characterized by acute follicular regression. Less than 1% of scalp hairs are in catagen at any given time.
  • Telogen – the 2- to 3-month resting phase of the hair follicle characterized by a stop in all activity. Approximately 5 to 10% of scalp hairs are in telogen at any given time.
  • Exogen – the daily shedding phase of the hair follicle characterized by a loss of 25 to 100 telogen hairs, which are replaced by new anagen hairs.

Androgenetic alopecia (AGA) – the most common etiology of hair loss wherein androgenetic effects, namely testosterone and dihydrotestosterone (DHT), disrupt the growth cycle (the anagen to telogen ratio decreases). Hallmark characteristics of AGA include thinning and subsequent miniaturization of terminal hairs to vellus hairs.[7]

Donor site: the non-alopecic areas (not influenced by androgenic alopecia) where donor terminal hairs can be harvested for implantation. The safe donor site of the scalp lies in the mid-occipital region between the upper and lower occipital protuberances. In general, there are 65 to 85 FUs per square centimeter (cm) in the occipital donor scalp.[8] Of note, hairs are finer in the inferior portion of the donor area and coarsest at the superior margin. The donor site represents the primary limiting factor in hair transplantation, regardless of the technique employed. In general, harvesting more than 15 to 20 FU per squared cm is ill-advised, as this may cause donor site thinning. NOTE: If necessary, the parietal scalp, submental region, chest and other parts of the body may be used as donor sites, though data regarding efficacy is limited and the hair characteristics can be very different from scalp hairs.[9]

Indications

Identifying appropriate candidates for hair transplantation includes an evaluation of the following[10]

  • Diagnosis: Fortunately, diagnosing androgenic alopecia is relatively straightforward and based upon the characteristic pattern of associated hair loss (Norwood for males, Ludwig for females), the miniaturization and depigmentation of hairs, and the lack of clinical inflammation. If these features are not present, further evaluation (i.e., laboratory, histopathology) may be warranted.
  • Age: The HT surgeon should only operate on patients older than 25 years of age because future hair loss pattern is less predictable and expectations are generally more unrealistic in patients younger than 25 years old.
  • Hair Caliber: Mathematically speaking, hairs with larger shaft diameter provide exponentially more surface area coverage; therefore, patients with thicker-caliber hair can expect to obtain much denser coverage (better aesthetic results) versus patients with thin-caliber hair (when controlled for number of follicular units transplanted).
  • Donor Hair Density: Patients whose scalp donor sites have greater than 80 FUs per squared cm are excellent candidates. Those with donor hair density less than 40 FUs per squared cm are considered poor candidates for HT, and the clinician needs to set patient expectations accordingly.[11]
  • Degree and Pattern of Baldness: patients hoping to correct frontal baldness can expect the most dramatic results in appearance, and thus represent great candidates. Grafting only the scalp vertex should be avoided if possible, as this not only consumes potential future donor grafts but also may cause a “doughnut” appearance as hair loss progression continues. The surgeon must reiterate that concentrating grafts in the frontal scalp will provide the maximum long-term density and minimal aesthetic risk.
  • Hair Color: In the light-skinned individual, patients with light-colored hair (i.e., blonde, red) are preferable to those with black hair since the color contrast between hair and skin is less noticeable. NOTE: proper technique helps mitigate most problems with transplanting dark-haired patients.
  • Patient expectations: Patients with realistic expectations and a history of compliance with hair loss medications/treatments (i.e., minoxidil, finasteride, platelet-rich plasma) represent ideal candidates. The patient must also understand the need for a conservative approach when recreating the anterior hairline so that it will have a natural appearance that lasts. Lastly, multiple hair transplantation sessions may be needed to achieve the desired results.

Two types of hair transplantation techniques predominate, including the follicular unit transplantation (FUT) and follicular unit extraction (FUE) techniques. Currently, FUE represents the more common approach due to its potential advantages over FUT,[12][13][14] which include:

  • Increased number of grafts are harvestable
  • The patient's hairstyle is not a factor since scarring is less apparent
  • Donor site laxity and density are not a significant deterrent
  • Postoperative pain is less
  • Postoperative healing time is less
  • The surgeon can target follicular groups of a specific size or hairs with a specific diameter or pigmentation
  • The surgeon can target hairs outside the typical donor site (i.e., parietal scalp, chest, back, beard, pubis) if needed.

On the contrary, FUT may be preferable to FUE given FUT’s reported advantages, which include: 

  • Shorter operative: Though FUE operative time is typically longer than FUT, recent advancements in FUE extraction techniques (e.g., automated mechanical instruments and robotic technology) may close this operative time gap by offering decreased extraction times compared to the traditional, manual FUE techniques
  • Less transection (of follicles) rate
  • Less of a learning curve 

Still, controversy remains as to which hair transplantation procedure is superior. Nevertheless, most HT surgeons would agree that deciding on whether to use FUE or FUT depends on several factors, some of which have been enumerated above. In summary, both FUT and FUE represent powerful techniques for improving the aesthetic appearance of the hair, and the astute hair transplantation surgeon should be knowledgable of the nuances of each.[15] 

Contraindications

During the preoperative HT consultation, the HT surgeon should identify patients who may not be candidates for surgery by eliciting the following information:

  • Hair loss history: associated symptoms (fever, pruritus, scaling, erythema, rash) suggesting an inflammatory condition (e.g., frontal fibrosing alopecia, lichen planopilaris), hair trauma (excessive brushing, scratching, blow-drying)
  • Medical History: skin conditions (i.e., vitiligo, pemphigus), thyroid disease, diabetes mellitus, metabolic syndrome, autoimmune-related conditions (e.g., lupus, sarcoidosis, scleroderma), systemic infections (i.e., HIV, tuberculosis, syphilis), local infections (i.e., tinea capitis, staphylococcal folliculitis), malnutrition and/or vitamin and mineral (iron) deficiency, recent childbirth, history of scar formation, chemotherapy and/or radiation exposure
  • Medications: Several medications may affect hair growth (i.e., propranolol, coumadin, amphetamines). Additionally, antiplatelet and anticoagulation medications should be stopped to mitigate bleeding risk.
  • Psychiatric History: stress, anxiety, eating disorders, trichotillomania, emotional trauma, body dysmorphic disorder (avoid operating on these patients due to low satisfaction rates and unrealistic expectations)
  • Physical Exam: hair loss that is localized, scarring, or inflammatory suggests a diagnosis other than androgenic alopecia. Additionally, a positive hair pull test (this should be negative in androgenic alopecia) would suggest an alternate diagnosis.
  • A scalp biopsy or KOH preparations may be warranted to rule out an inflammatory or infectious cause of hair loss, respectively. Hormonal studies also may be necessary, especially in women, if hyperandrogenemia is suspected (recalcitrant acne or virilization is often present).

Depending on the findings as obtained from the above examination, the surgeon should refer the patient to the appropriate physician or specialist (i.e., primary care, dermatology, rheumatology, endocrinology, psychiatry, pathologist) for further workup and/or management.[10][16][17][18][19]

In summary, potential exclusionary criteria, or “red flags” for HT would include:

  • Unrealistic expectations
  • Mental illness      
  • Donor site miniaturization       
  • Unusual hair loss pattern  
  • Many broken hairs            
  • Excessive shedding           
  • Scalp inflammation           
  • Unexplained scarring        
  • Scalp or skin pain, burning, pruritus      

Equipment

  • Local anesthesia, such as 1 to 1 mix of 1% lidocaine with 1 to 100000 epinephrine, with 0.5% bupivacaine with 1 to 200000 epinephrine
  • Tumescent anesthesia (with diluted epinephrine)
  • Tumescent saline
  • Great lighting
  • Comfortable, ergonomic chairs and tables
  • Magnification (with microscopes and/or high-powered loupes)
  • Topical antiseptic
  • Scalpel for strip harvest if applicable
  • Skin retractors
  • FUE punch devices (manual or motorized)
  • Micro-forceps (e.g., jewelers)
  • Graft holding solution (chilled sterile saline)
  • Cotton-tip applicators
  • Suture or staples for skin closure if strip method employed
  • Non-adhesive dressing
  • Petroleum jelly or antibiotic ointment

Personnel

Contemporary hair transplantation requires a well-trained and efficient surgical team, including:

  • Surgeon: in addition to marking the hairline and harvesting the grafts from the donor site, the physician closely supervises the quality of graft creation and placement by the technicians
  • Hair technicians (typically 1 to 4 are needed depending on the technique used, surgeon involvement, and number of grafts required)
  • Operative nurse
  • Surgical scrub technician

Preparation

The desired recipient graft number (total number of grafts needed) is calculated by multiplying the measured recipient area by the desired graft density (target density should be around 30 FUs per cm^2). If planning FUT for graft harvest, the strip length is calculated by dividing the desired recipient graft number by the donor site density (using a densitometer). The strip should be around 1 to 1.5 cm wide, but no larger to allow tension-free wound closure.[5]

Anxiolytics may be given pre-operatively, per surgeon and patient preference.

The administration of antibiotics covering skin flora should is necessary pre-operatively.

A single dose of pre-operative systemic steroids (i.e., 40 mg of prednisone) may help with scalp swelling.

The recipient area is marked, including the proposed hairline and direction/pattern of native FUs.

The donor site is shaved and marked according to the technique employed.

Anesthesia is obtained using a combination of local injections and regional nerve blocks (supraorbital, supratrochlear, zygomaticofrontal, and occipital).[20]  

Tumescent anesthesia and tumescent saline are infiltrated to the proposed donor and implantation sites as needed to facilitate graft harvest and placement, respectively.

Technique

While several surgical treatment options (plug grafts, scalp reductions, transposition flaps) have been used historically to treat androgenic alopecia, we outline the two most common techniques of HT based on the follicular unit-principle, namely the follicular unit transplantation (FUT) and the follicular unit excision (FUE).

FUT Donor Site Harvest: [21][22]

  • The patient placement is in a prone position.
  • If not done already, the donor site hair is trimmed to 2 mm.
  • The calculated strip length is marked, and a local anesthetic is injected superficially into the dermis. A tumescent solution may be injected as well to increase anesthesia, hemostasis, and dermal turgor.
  • A beveled incision is made parallel to the exiting follicles, into but not beyond the subcutaneous tissue (about 4 to 5 mm in depth).
  • With lateral retraction around the periphery using sharp skin hooks, the donor strip gets dissected off the galea aponeurosis and occipital fascia which minimizes bleeding and sensory nerve damage. NOTE: cauterization should be used sparingly to decrease the risk of permanent FU damage.
  • The donor strip gets prepared by removing excess subcutaneous tissue, with care to leave 2 mm of fat beneath the FU to avoid damage to the follicle.
  • The strip is then dissected (usually by a technician) under magnification into vertical segments one FU thick.
  • Individual FUs are then isolated with further sharp strip dissection and placed immediately into a holding medium of chilled saline. NOTE: the FU is susceptible to desiccation in just a few minutes, which renders the graft unusable.
  • The donor strip is then closed either primarily or with a two-layer closure using sutures and/or staples per surgeon preference.
  • The patient transitions to a sitting position for recipient site preparation and graft implantation.

FUE Donor Site Harvest[23][24][25]:

  • The donor site is shaved to 2 mm to visualize the angle of the follicles.
  • The patient placement is in a prone position for ease of harvesting.
  • Local and tumescent anesthesia gets injected into the donor site.
  • If manual FUE is being performed, a sharp punch (diameter 0.8 to 1.2 mm) is oriented within the center of the hair follicle at the same angle and advanced in an oscillating motion to a depth of 4 mm or less to prevent transection.
  • The FU is removed using delicate forceps in an atraumatic fashion and placed either directly into the recipient site (after inspection of FU integrity) or a holding medium of chilled sterile saline.
  • The patient then gets transitioned to a sitting position in preparation for recipient site implantation.
  • NOTE: Modifications of the manual sharp FUE technique include the manual dull punch technique, the use of powered devices with oscillatory or rotating punches, or employing a vacuum apparatus to facilitate atraumatic extraction. Regardless of the technique used, a 5% transection rate is generally acceptable.[24]

Recipient Site Creation and Implantation[21][26]:

  • No matter the harvest technique used (FUE or FUT), the implantation process must also take place in an atraumatic and meticulous fashion. For instance, grafts should only be manipulated using the perifollicular tissue. Furthermore, grafting should be done expeditiously, since prolonged exposure of the FU will cause graft desiccation.
  • Attention to the recipient's hair pattern is important to promote a natural-looking result. For example, hair along the frontal scalp hairline points anteriorly at an angle of 15 to 20 degrees, while hair follicles in the temporal region are oriented inferiorly. Also, the surgeon should strive to recreate a sharp temporal recess in males and a rounded temporal recess in females. Lastly, the angles and spiraled orientation of the crown should be followed to create a natural result. ([27][28][29])
  • The recipient sites for the FUs are then created in a random and irregular pattern under magnification using either flat-edged blades or a combination of needles (19 or 21 gauge), with care not to transect the native follicles.
  • The graft is gently placed into the recipient site, with light pressure applied for several seconds with a wet cotton-tip applicator to promote hemostasis and to avoid graft extrusion or “popping.”
  • An emollient or antibiotic ointment and a non-adhesive bandage are placed gently across the donor and recipient sites.

Miscellaneous:

  • ROBOT Follicular Unit Extraction: More recently, robotic devices have been developed with potential advantages including more accurate and faster graft harvesting, decreased FU transection rate, and increased implantation accuracy at the recipient site, though comparative studies are lacking. Regardless, the robot offers a promising technique to maximize HT outcomes.[30][31]
  • Facial Hair Restoration: While the focus of this article was to discuss the nuances of HT for the scalp, facial HT techniques may also be applied to obtain dramatic results when restoring facial hair such as eyebrows, beards, and sideburns.[32][33]

Complications

In general, complications after hair transplantation are rare, given the vigorous blood-supply to the scalp, which allows for quick healing and low rates of infection. Nevertheless, potential complications include[34][35][36]:

  • Edema (5%)
  • Bleeding (0.5%)
  • Folliculitis
  • Numbness of the scalp – may be temporary, and rarely permanent especially if dissection remains superficial to the galea aponeurosis and occipital fascia
  • Telogen effluvium – an uncommon but concerning complication characterized by shedding of native hairs at the donor or recipient site. This “shock” loss, likely a result of stress and microtrauma sustained during HT, is transient. Patients should receive reassurance that the majority of the hairs shed will return at 3 to 4 months.
  • Epidermal cysts and Ingrown Hair – these processes, although self-limited, may rarely set off a diffuse inflammatory response affecting the entire graft population. Releasing entrapped hairs should hasten resolution.
  • Infection – given the robust blood supply of the scalp, infection affects less than 1% of patients. Treatment includes exfoliations with warm compresses, twice-daily shampooing, and antibiotics.

Clinical Significance

Hair transplantation represents a powerful tool that can restore a more youthful appearance to those affected by androgenic alopecia. When performing hair transplantation, proper patient evaluation and execution of a comprehensive treatment plan can produce safe, reliable, and satisfactory outcomes.[1][37]

Enhancing Healthcare Team Outcomes

It remains imperative to identify the risk factors and perform a thorough assessment of the patient prior to performing hair transplantation. A team approach is an ideal way to limit the complications of this procedure. Before surgery, the patient should have the following done:

Evaluation by a surgeon experienced in selecting the appropriate patient for HT.

Evaluation by a primary care physician to diagnose and/or treat potentially reversible causes of hair loss (e.g., hypothyroidism, hormonal imbalance, malnutrition), if applicable.  

Evaluation by a dermatologist to diagnose and/or treat inflammatory causes of hair loss (e.g., lichen planopilaris), if suspected either on physical exam, laboratory studies, or histopathological analysis.

The pharmacist will have some involvement, depending on the medication needs surrounding the procedure.  The pharmacist should examine the patient's medication record and ensure everything is in place for the hair transplantation, and that there are no drug interactions. Any concerns should be reported to the nurse to pass on to the clinician. Nursing will have extensive involvement, including preparation, assistance intraoperatively, and monitoring and followup. Nursing duties are covered in more detail in the following sections.

An interprofessional team of an experienced surgeon, hair technicians, and operative nurses should be involved during the HT to maximize outcomes. Close follow-up during the initial post-operative period, either by a wound care nurse and/or clinician experienced in the post-operative care of HT, should monitor the patient for possible complications including infection or hematoma. It is also important to provide patient education on properly maintaining the surgical wounds. The patient should also avoid strenuous activity for 1 to 2 weeks to help prevent complications.[1][3][38] This overall interprofessional approach will result in the best patient outcomes with minimal adverse events.[Level V]

Nursing, Allied Health, and Interprofessional Team Interventions

Adequate pain medication is appropriate, as patients often report mild harvest and donor site pain for 1 to 2 days postoperatively. To minimize edema and ecchymosis, the patient may intermittently ice the affected areas for 48 hours, sleep with their head elevated for one week, and avoid vigorous activity for two weeks. The patient may be given a low-dose corticosteroid taper to help lessen bruising and swelling as well. Post-operative antibiotics are often prescribed as well to mitigate infection, though data supporting its routine use is limited. To promote wound healing, the patient is instructed to keep the affected areas moist by routine application of an emollient for the first several days. Also, a small spray bottle may be used to gently apply moisture to the area, which also helps prevent scabbing. Regular shampooing may resume on postoperative day 2, though caution is advised against scratching/itching the scalp, and to avoid direct water contact from a high-pressure faucet or showerhead. Patients are asked to return at seven days for suture removal (if applicable) and are followed closely over the following months until the maturation of the implanted grafts (around 6 to 12 months) occurs.  Photographic documentation should occur at around 6 to 12 months postoperatively. Topical minoxidil, oral finasteride, and low-level light therapy may be continued throughout the perioperative period and indefinitely after that to help maximize results.[1][3][38]

Nursing, Allied Health, and Interprofessional Team Monitoring

Close follow-up during the initial post-operative period, either by a wound care nurse and/or clinician experienced in the post-operative care of HT, should monitor the patient for possible complications including infection and ingrown hair formation. The patient should receive counsel that loss of the implanted hairs normally occurs after several days and may take several months to grow. There may also be surrounding native hair loss at the donor or recipient site, though the patient should understand that this “shock loss” is normally transient and to expect a full recovery after a few months.


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