Hair Transplantation

Anatomy and Physiology

Pertinent Anatomy and Definitions

Humans have 2 types of hair follicles—terminal and vellus. Terminal hair follicles are larger and extend deeper into the skin, reaching the subcutaneous fat. These follicles produce thicker hairs, typically greater than 0.06 mm in diameter. In contrast, vellus hair follicles are smaller, reach only into the reticular dermis, and produce short, fine hairs typically less than 0.03 mm in diameter. Hairs between 0.03 and 0.06 mm are sometimes called intermediate hairs. At birth, terminal hairs appear on the scalp, eyebrows, and eyelashes, whereas vellus hairs cover most other areas. During puberty, vellus hairs in regions such as the axilla and genital area convert to terminal hairs. Pathologic transitions can also occur. Vellus-to-terminal conversion is observed in hirsutism in women, whereas terminal-to-vellus transformation, referred to as miniaturization, is characteristic of androgenetic alopecia.

The scalp consists of 5 layers, which can be remembered using the mnemonic SCALP:

• Skin or epidermis
• Connective tissue
• Aponeurosis
• Loose connective tissue
• Periosteum over the cranium

The skin and subcutaneous tissue contain the hair follicles. These 2 layers undergo thinning in patients affected by alopecia. The subcutaneous layer is quite vascular. Staying superficial along the connective subcutaneous tissue layer during hair transplantation prevents a disruption in the blood supply. 

Hair Follicle 

Generally, the human scalp contains approximately 100,000 to 150,000 hair follicles. Each follicle consists of the hair shaft, inner and outer surrounding sheaths, and a germinative bulb. The follicle is divided into 4 sections. 

• Bulb: The bulb is the deepest part of the hair follicle and contains the hair matrix, dermal papilla, and melanocytes.
  • The hair matrix generates the hair shaft.
  • The dermal papilla controls growth signals.
  • Melanocytes provide pigment for hair color.

• Suprabulbar region: The suprabulbar region extends from the bulb to the isthmus.
• Isthmus: The isthmus lies between the sebaceous duct opening and the bulge or arrector pili muscle insertion. 
• Infundibulum: The infundibulum begins at the surface of the epidermis and extends to the opening of the sebaceous duct. 

A follicular unit is a naturally occurring group of hair dispersed throughout the scalp consisting of 1 to 4 terminal hairs, a sebaceous gland and duct, and an arrector pili muscle. The collagen band surrounding the follicular unit is the perifolliculum. Transplantation of only the follicular unit bundles provides the most optimal cosmetic results.

The hair shaft consists of 3 components.

• Medulla: The medulla, surrounded by the cortex and the cuticle, is the innermost layer.
• Inner root sheath: The inner root sheath surrounds the hair shaft from the bulb to the isthmus and plays a key role in shaping its structure. This sheath consists of the cuticle of the inner root sheath, the Huxley layer, the Henle layer, and the companion layer. 
• Outer root sheath: The outer root sheath extends from the bulb to the epidermis and surrounds the inner root sheath and the hair shaft.

Hair Growth Cycle

The hair growth cycle consists of 4 phases—anagen, catagen, telogen, and exogen.

• Anagen: Anagen is the active growing phase of the hair follicle, lasting 2 to 6 years. Approximately 90% to 95% of scalp hairs are in the anagen phase at any given time.[8]
• Catagen: Catagen refers to the involutional phase of the hair follicle characterized by acute follicular regression. Catagen typically lasts 2 to 3 weeks, and at any given time, less than 1% of scalp hairs are in catagen.
• Telogen: Telogen refers to the resting phase of the hair follicle, lasting 2 to 3 months, and a cessation of all activity marks this phase. Approximately 5% to 10% of scalp hairs are in the telogen phase at any given time.
• Exogen: Exogen is the daily shedding of hair follicles characterized by a loss of 25 to 100 telogen hairs, replaced by new anagen hairs.

Pathophysiology of Androgenetic Alopecia  

Androgenic alopecia is the most common cause of hair loss and is considered a heritable disorder. In men, androgens, particularly testosterone and dihydrotestosterone, disrupt the growth cycle, resulting in a shortening of the anagen phase. The enzyme 5-α reductase converts testosterone to dihydrotestosterone in the bloodstream and the scalp, which links to susceptible hair follicles, causing miniaturization of the hair. Hallmark characteristics of androgenic alopecia include thinning and subsequent miniaturization of the androgen-sensitive, thick, pigmented terminal hair at the top of the scalp, beard, axillary, and pubic regions. Terminal hair converts into vellus hair, or fine, short, nonpigmented hair found in adults that covers much of the body.[9] The hair elsewhere, including the parietal and occipital scalp, is androgen-insensitive. Research reveals that young men with androgenic alopecia have higher levels of cellular 5-α reductase, a greater quantity of androgen receptors in the balding scalp compared to the nonbalding scalp, and higher rates of dihydrotestosterone production.[10][11] Experts do not completely understand the underlying pathophysiology in women. Researchers still believe that hormonal factors and genetic predisposition play a role; however, the exact contribution of these factors is unclear.

Diagnosing androgenic alopecia is typically straightforward and relies on recognizing the characteristic patterns of hair loss, including miniaturization and depigmentation of hair beginning in the temporal, midfrontal, or vertex areas of the scalp, as well as the absence of clinical inflammation. If these features are absent, further evaluation may be necessary. Male pattern hair loss is most commonly classified using the Norwood system, whereas the Ludwig classification is typically used to describe female pattern hair loss. Androgenic alopecia in women typically spares the hairline but presents with more diffuse thinning throughout the top and upper sides of the head.

Indications

Appropriate indications for hair transplantation include:

• Hamilton-Norwood III to V male pattern hair loss
• Ludwig stage II and III female pattern hair loss
• Traction alopecia
• Inactive lichen planopilaris
• Inactive frontal fibrosing alopecia (a variant of lichen planopilaris)
• Inactive folliculitis decalvans
• Pubic, facial, and body hair placement for patients undergoing gender-affirming care
• Scarring alopecia from surgeries such as cleft lip scar repair and other surgical scars
• Facial hair restoration for eyebrows, beards, and sideburns after facial trauma or burns [12][13][14][15]

The active phase of frontal fibrosing alopecia, lichen planopilaris, and folliculitis decalvans is a contraindication to hair transplantation[16]. Patients affected by these diseases should wait to undergo hair transplantation until they have been disease-free for several years. Despite waiting for a period of disease inactivity, hair transplantation in patients with frontal fibrosing alopecia should be performed with caution and with clear expectations. Studies reveal that the graft survival rates after 1, 2, 3, and 5 years were 87%, 71%, 60%, and 41% respectively.[17][18][19] Patients should continue therapy for frontal fibrosing alopecia following hair transplantation to avoid disease recurrence.[17] Likewise, hair transplantation can reactivate discoid lupus erythematosus, folliculitis decalvans, and other inflammatory conditions.

Contraindications

Obtaining a detailed history and performing a thorough physical examination are essential to ensure appropriate candidacy and optimize outcomes for patients considering hair transplantation. Clinicians should inquire about the pattern and symptoms of hair loss. Signs such as fever, itching, scaling, redness, or rash suggest inflammatory conditions. The medical history should include a review of dermatologic diseases, thyroid disorders, diabetes mellitus, autoimmune conditions, infections, nutritional deficiencies, recent childbirth, prior scarring, and exposure to chemotherapy or radiation, all of which can impact the results. Medication use is also important, as drugs such as propranolol, warfarin, and amphetamines can affect hair growth. Discontinuing antiplatelet and anticoagulation medications before hair transplantation can help mitigate the risk of bleeding. A detailed psychiatric history is needed to assess for stress, anxiety, eating disorders, trichotillomania, emotional trauma, and body dysmorphic disorder, as these factors may increase the risk of dissatisfaction. A physical examination should evaluate for signs of localized scarring or inflammatory hair loss, and a positive hair pull test may indicate an alternative diagnosis, such as telogen effluvium, anagen effluvium, or alopecia areata.[4][20][21][22][23]

Contraindications

Diffuse unpatterned alopecia: Patients with diffuse unpatterned alopecia experience hair loss that affects the temporal, parietal, and occipital scalp areas. Donor hair must be retrieved from a portion of the scalp not affected by alopecia. If the patient has no such area on the scalp, hair transplantation may not be successful. 

Cicatricial alopecias: Cicatricial alopecias are inflammatory conditions that destroy hair follicles, leading to scarring and permanent hair loss. Common examples include lichen planopilaris and discoid lupus erythematosus. Physical examination findings include patchy hair loss, redness around the base of hair follicles as they exit the skin, shininess of the skin, scarring of the scalp, or hair loss without miniaturization. Hair transplantation is contraindicated in active cicatricial alopecias as the likelihood of failure is high, and the procedure can worsen or exacerbate the disease.[24] Once the patient has been disease-free for 2 years, hair transplantation can be considered. Patients should undergo dermoscopy and scalp biopsy before hair transplantation. The patient must understand that the results are likely suboptimal and may be temporary.[25]

Alopecia areata: Alopecia areata is an autoimmune condition that affects the hair follicles. Affected patients may have patchy hair loss on the scalp, beard, or body. Diagnosis can be confirmed through dermoscopy and biopsy. Hair transplantation may be considered after a minimum of two years without active disease; however, outcomes are often suboptimal, and there remains a risk of disease recurrence.

Patients with unstable hair loss: Patients currently experiencing a rapid degree of hair loss or those with more than 15% miniaturization in the recipient area should receive medical therapy for 6 to 12 months to allow for stabilization before undergoing hair transplantation. A high degree of miniaturization puts the patient at risk for shock loss at the recipient site, which can be permanent.

Patients with insufficient hair loss: Patients typically lose 50% of their native hair before hair loss becomes noticeable, which is the threshold at which clinicians consider hair transplantation. Patients with less than 50% hair loss should use medical therapy until hair loss exceeds 50%.

Young patients: Male pattern hair loss in young individuals often progresses rapidly. Hair transplantation performed too early can deplete the donor supply and compromise long-term results. The preferred management is to defer hair transplantation and initiate medical therapy for at least 1 year, with reassessment at that time. Ideally, transplantation should be considered only after age 25.

Patients with unrealistic expectations: Patients must understand that hair transplantation does not restore hair to or exceed pre-balding amounts. Some of the scalp may still be visible, and some scarring is expected to occur. The goal is to create the illusion of density.

Patients with psychological disorders: Patients with body dysmorphic disorder are at a high risk of being dissatisfied with the outcome. Recognition of patients with body dysmorphic disorder is imperative. Affected patients focus on absent or perceived minor defects that are not evident to the general population. These patients spend hours each day fixated on the defect and have likely undergone multiple cosmetic procedures. Trichotillomania is an obsessive-compulsive disorder marked by the recurrent pulling out of one's hair. Clinicians should defer transplantation until the patient undergoes psychological evaluation and the condition has stabilized.

Medical Conditions that Complicate Hair Transplantation

• Smoking
• Diabetes mellitus with microvascular damage
• Advanced balding
• Hypertension
• Excessive alcohol use
• Heart disease
• Immune deficiency
• Advanced sun damage to the scalp [25]

Equipment

General Requirements and Equipment for Operating Suites

• Operating room measuring a minimum of 3.6 × 3.6 m (12 × 12 ft) with a minimum height of 3.0 m (10 ft)
• A dissection room of equal size to the minimum requirement for the operating room, or consist of a single large room measuring 6 × 3.6 m (20 × 12 ft)
• An operating room door measuring wider than 0.6 m (2 ft) to allow for a stretcher in the event of an emergency
• Adequate overhead surgical lighting to ensure a well-illuminated sterile field
• Autoclave or chemical method to sterilize instruments
• Blood pressure monitor
• Stethoscope
• Pulse oximeter
• Glucometer
• Digital thermometer
• Weighing scale
• Local anesthesia with or without epinephrine
• Tumescent saline
• Comfortable, ergonomic chairs and tables
• Magnification with microscopes and high-powered loupes
• Topical antiseptic
• Scalpel for strip harvest if applicable
• Skin retractors
• Follicular unit extraction punch devices
• Micro-forceps
• Graft holding solution
• Cotton-tip applicators
• Suture or staples for skin closure if using the strip method
• Sharps containers, biohazard bags, and waste disposal systems
• Nonadhesive dressing
• Sterile gloves, gowns, and drapes [26]

Local Anesthetic Options and Dosage Guidelines

• Lignocaine: A maximum daily dose of 300 mg or 4.5 mg/kg of body weight, which may be increased to 500 mg or 7 mg/kg when combined with epinephrine
• Bupivacaine: A maximum daily dose of 175 mg
• Levobupivacaine with or without epinephrine: A maximum dose of 2 mg/kg and a maximum one-time dose of 200 mg
• Epinephrine: A maximum dose of 0.01 mg/kg body weight.

Equipment and Medications Necessary in the Event of an Emergency

• Intravenous (IV) access cannulas and IV sets
• Laryngoscope
• Endotracheal tubes
• Syringe to inflate the cuff on the endotracheal tube
• Suction equipment
• Xylocaine spray
• Oropharyngeal and nasopharyngeal airways
• Ambu bag
• Oxygen cylinders with flow meter, tubing, catheter, face mask, and nasal prongs
• Defibrillator with accessories
• Electrocardiogram machine
• Injectable calcium chloride 1 gm/10 mL syringe
• Injectable amiodarone 150 mg/3mL vial
• Injectable epinephrine 1 mg/10 (1:10,000) mL or 1mg/mL (1:1000) vials
• Injectable hydrocortisone 100 mg
• Injectable atropine 1 mg/10 mL syringe
• Injectable promethazine 25 mg/mL
• Injectable furosemide 10 mg/mL
• Injectable metoclopramide 5 mg/mL
• Injectable dexamethasone 10 mg/mL
• Injectable diazepam 5 mg/mL or 10 mg/2 mL
• Injectable lidocaine 100 mg/5mL syringes
• Injectable cetirizine 10 mg/mL or diphenhydramine 50 mg/mL
• Dopamine 400 mg/250 mL IV bag
• Dextrose 50% 0.5 mg/mL 50 mL syringe
• Normal saline 500 mL
• Lidocaine 2 g/250 mL IV bag
• Povidone-iodine swab stick
• Sodium bicarbonate 50 mEq/50 mL syringe
• Sodium chloride 0.9% 10 mL vial and 20 mL vial
• Sterile water
• Vasopressin 20 units/mL 1 mL vial [26]  

Personnel

Contemporary hair transplantation involves a multidisciplinary team, including surgeons, hair technicians, operating room nurses, and surgical scrub technicians. Typically, 1 to 4 technicians are required, depending on the specific technique, the surgeon's involvement, and the number of grafts needed. Both the surgeon and at least 1 surgical assistant or technician need basic life support and advanced cardiac life support training.

Preparation

Preoperative Testing

Preoperative evaluation for hair transplantation should include the following:

• Trichoscopy to exclude subtle forms of cicatricial alopecia and nonfocal forms of alopecia areata
• Complete blood count, including platelets
• Prothrombin time
• Activated partial thromboplastin time
• Total iron, ferritin, thyroid function tests (including thyroid-stimulating hormone), total and free testosterone, and dehydroepiandrosterone sulfate in female patients
• Fasting blood glucose and hemoglobin A_1c in patients with diabetes mellitus
• HIV, hepatitis B, and hepatitis C
• Scalp biopsy or KOH preparations if the clinician suspects an infectious or inflammatory cause of alopecia [27]

A routine electrocardiogram is not necessary unless the patient has a history of cardiac disease, morbid obesity, or metabolic syndrome. Patients with diabetes mellitus and hypertension should have their conditions under good control before proceeding with hair transplantation.

Patient Instructions Before Surgery

According to an international expert consensus statement, patients undergoing hair transplantation should follow these presurgical instructions:[27]

• Avoid wearing clothing that must be pulled over the head on the day of surgery.
• Discontinue minoxidil 1 week before the procedure.
• Avoid alcohol and recreational drugs for 3 days before surgery.
• Stop smoking 3 to 6 weeks before surgery and continue abstinence for the same duration postoperatively; long-term cessation yields the best outcomes.
• Provide preoperative anxiolytics such as alprazolam as needed for anxiety.
• Discontinue nonsteroidal anti-inflammatory medications 7 days before surgery.
• Continue antihypertensive medications.
• Discontinue vitamin supplements and herbal preparations 1 week before surgery.
• Discontinue antiplatelet and anticoagulant medications 72 to 96 hours before transplantation based on risks versus benefits and with approval from the prescribing provider. Low-dose aspirin does not require discontinuation.
• Shower or bathe using shampoo or chlorhexidine gluconate (4%) with shampoo the night before and on the morning of surgery.
• Discontinue the use of sprays, gels, wax, and other hair styling products 24 hours before surgery.
• Avoid dying hair 3 to 4 days before surgery.
• Trim or shave the head a day before surgery, leaving the donor area with hair around 0.5 to 1.5 mm in length for visualization and orientation.
• Fasting is not required unless undergoing light IV sedation. Patients who undergo IV sedation should fast for 6 hours.
• Discuss the risks, benefits, and alternative therapies.

Patient Preparation on the Day of Surgery

Preoperative medications typically include antibiotic prophylaxis with a cephalosporin. For patients allergic to penicillin, a macrolide or clindamycin may be used as an alternative. Additionally, a corticosteroid such as 8 mg of methylprednisolone and an oral antiemetic are administered 30 minutes before surgery. Corticosteroids help reduce scalp swelling, and clinicians may choose to administer them in various ways, including intramuscular injections, short courses of oral therapy, or mixed with local anesthesia, such as triamcinolone. Additionally, some clinicians apply EMLA cream 1 to 2 hours beforehand to provide superficial anesthesia before using injectable anesthetics.[28][29]

Technique or Treatment

Harvesting of follicular units during follicular unit transplantation involves harvesting strips, followed by dissection into small follicular units. In contrast,  follicular unit extraction involves the direct harvesting of individual follicular units. Currently, follicular unit extraction is the more commonly used technique due to the following advantages:

• Increased number of harvestable grafts
• Less apparent scarring
• Minimal graft preparation required
• Feasible even on tight scalps
• Minimal risk of nerve injury or excessive bleeding
• Less postoperative pain
• Decreased postoperative healing time
• Allows targeting of follicular groups based on specific size, hair diameter, or pigmentation
• The surgeon can selectively pick grafts and target hairs outside the typical donor site, such as the parietal scalp, chest, back, beard, and pubis, if needed [30][31][32] 

However, follicular unit transplantation may be preferable in certain patients due to its reported benefits:

• Shorter operative time
• Less transection of follicles and a higher survival rate of the grafts
• More useful for patients with advanced alopecia due to the large number of grafts from a single strip
• More precise grafts enable denser packing potential, resulting in cosmetically better outcomes [30][31][32] 

The most appropriate technique for a hair transplant depends on individual factors, including the extent of hair loss, the availability of the donor area, and the desired results. Patients with Afro-textured hair should choose a surgeon experienced in managing this type of hair, as they can provide specialized techniques necessary for optimal care and results.[33] Hair transplantation in patients with Afro-textured hair requires clinicians to adapt their approach to account for naturally curved or C-shaped follicles, which can be more prone to damage during extraction and implantation.[33] This structural feature increases the risk of follicle transection and can affect graft survival. Additionally, individuals with darker skin have a higher risk of keloid scarring in both donor and recipient areas. Denser, patchy growth patterns may limit the availability of donor hair. Surgeons must carefully tailor surgical techniques to preserve follicle integrity and ensure proper angulation for a natural appearance. Hairline design, in particular, requires special attention to maintain the typically lower, straighter aesthetic characteristic of black hair. Some studies also suggest a slightly higher risk of postoperative infection or inflammation in these cases, underscoring the need for experienced surgical planning and careful follow-up. 

Although follicular unit extraction operative time is typically longer than follicular unit transplantation, the use of automated mechanical instruments and robotic technology for follicular unit extraction may help close this operative time gap by offering shorter extraction times compared to traditional, manual follicular unit extraction techniques.[34] 

Follicular Unit Transplantation Donor Site Harvest 

The steps for follicular unit transplantation donor site harvest are as follows:[35][36]

• Trim the donor site hair to 0.5 to 1.5 mm to visualize the angle of the follicles, if not already completed.
• Place the patient in the prone, supine, or lateral position for ease of harvesting.
• Clean the area with povidone-iodine or chlorhexidine solution.
• Mark the recipient area, including the proposed hairline, along with the direction and pattern of native follicular units.
• Mark the calculated strip length.
• Administer anesthesia beginning with regional nerve blocks—supraorbital, supratrochlear, zygomaticofrontal, and occipital—followed by tumescent infiltration of the donor and recipient areas with a mixture of 30 mL of 2% lignocaine mixed with 5 mL of 0.5% bupivacaine, 30 mL of normal saline, 0.5 mL of epinephrine 1 mg/mL solution, and 1 mL of triamcinolone 40 mg/mL. The specific techniques for administering anesthesia, including the use of regional blocks, can vary slightly depending on the procedure and the surgeon's preference. Specific formula adjustments may also vary based on the surgeon.
• Make a beveled incision parallel to the exiting follicles, into but not beyond the subcutaneous tissue, approximately 4 to 5 mm deep.
• With lateral retraction around the periphery using sharp skin hooks, dissect away the donor strip from the galea aponeurosis and occipital fascia. Use cauterization sparingly to decrease the risk of permanent follicular unit damage.
• Remove excess subcutaneous tissue from the donor strip, leaving 2 mm of fat beneath the follicular unit to avoid damage to the follicle.
• Dissect the strip under magnification into vertical segments, each measuring 1 follicular unit in thickness.
• Isolate individual follicle units through sharp dissection of the strip and place them immediately into a holding medium of chilled saline, as follicle units are susceptible to desiccation in just a few minutes, rendering the graft unusable.
• Once harvested, close the donor strip with a double-layer closure using sutures and staples, as preferred by the surgeon.
• Transition the patient to a seated position for recipient site preparation and graft implantation.

Follicular Unit Extraction Donor Site Harvest

The steps for follicular unit extraction donor site harvest are as follows:[37][38][39][40]

• Shave the donor site to a depth of 0.5 to 1.5 mm to visualize the angle of the follicles, if not already done.
• Place the patient in a prone, supine, or lateral position.
• Clean the area with povidone-iodine or chlorhexidine solution.
• Administer anesthesia beginning with regional nerve blocks—supraorbital, supratrochlear, zygomaticofrontal, and occipital—followed by tumescent infiltration of the donor and recipient areas using a solution composed of 30 mL 2% lignocaine mixed with 5 mL 0.5% bupivacaine, 30 mL normal saline, 0.5 mL of epinephrine 1 mg/mL, and 1 mL of triamcinolone 40 mg/mL in a normal adult patient. Specific anesthetic formulations can be adjusted according to the surgeon's preference. The specific techniques for administering anesthesia, including the use of regional blocks, can vary slightly depending on the procedure and the surgeon's preference. Specific formula adjustments may also vary based on the surgeon.
• Harvest follicular units with a motorized or manual punch and forceps.
• Perform a FOX test on the initial grafts to assess the ease of extraction and the quality of the extracted grafts. FOX 1 or 2 grafts are easily extracted with minimal transection and are ideal for follicular unit extraction. FOX 3 is considered neutral. Patients with FOX 4 or 5—where graft extraction is challenging due to a high transection rate and increased risk of surrounding tissue damage—are better suited for follicular unit transplantation.
• Most follicular unit extraction experts recommend a safe single-pass density of 10 to 15 excisions/cm².

Manual Follicular Unit Extraction

• Position a 0.8- to 1.2-mm sharp punch within the center of the hair follicle at the same angle and advance in an oscillating motion or using a direct method by pushing the punch into the skin without rotation to a depth of 2 to 3 mm to prevent transection. For patients with Afro-textured hair, surgeons often employ a curved insertion and dissection technique using a specialized punch, such as the UPunch Curl, to follow the natural curl of the follicles.
• Remove the follicular unit using delicate forceps in an atraumatic fashion and place it either directly onto the recipient site or in a holding medium of chilled, sterile saline.
• Transition the patient to a seated position to prepare for graft implantation.
• A 5% transection rate is generally acceptable.[39]

Motorized Follicular Unit Extraction 

Motorized follicular unit extraction techniques require careful customization and adjustments throughout the procedure to ensure optimal outcomes. Motorized sharp systems require the lowest revolutions per minute, which cuts cleanly without skin distortion, typically starting at 1000 to 2000 rpm with an insertion depth of 2.0 to 3.0 mm, and utilize a single-stage punch insertion. Motorized hybrid systems typically use an oscillation arc of 50° to 60° at 70 to 80 oscillations/min, employing a 2-stage technique—holding the punch steady to incise the epidermis, then allowing it to work deeper without pushing, usually to a depth of 3.5 to 4.0 mm. Motorized blunt systems also require individualized settings and test grafts, with typical insertion depths ranging from 4.0 to 5.0 mm (varying by ethnicity) and speeds of 1000 to 1500 rpm, advancing the punch to the desired depth after incising the epidermis. Robotic-assisted follicular unit extraction requires precise placement of the tensioner and continuous monitoring, with settings for sharp and dull punch depths, punch size, and targeting patterns determined by the surgeon or their assistant under direct supervision.

The more recent development of robotic devices enables more accurate and faster graft harvesting, a decreased follicular unit transection rate, and increased implantation accuracy at the recipient site; however, comparative studies are lacking. Regardless, the robot offers a promising technique to maximize hair transplantation outcomes.[41][42]

Recipient Site Creation and Implantation

Careful attention to the recipient's natural hair pattern is crucial for achieving realistic results. For instance, hair along the frontal hairline typically angles forward at an angle of 15° to 20°, whereas follicles in the temporal area point downward. Surgeons aim to recreate a sharp temporal recess in men and a more rounded recess in women. To ensure a natural appearance, they also follow the angles and spiral pattern of the crown.[43][44][45]

Clinicians calculate the desired recipient graft number or total number of grafts needed by multiplying the measured recipient area by the desired graft density. The target density should be approximately 30 follicular units/cm². If planning follicular unit transplantation for graft harvest, the length of the strip should be determined by dividing the desired recipient graft number by the donor site density using a densitometer. The strip should be approximately 1 to 1.5 cm wide but no larger to allow for tension-free wound closure.[46]

The steps for recipient site creation and implantation are as follows:[35][47][48]

• To avoid trauma, manipulate grafts using only the perifollicular tissue.  
• Under magnification, create recipient sites in a random and irregular pattern using either flat-edged blades or a combination of 19- or 21-gauge needles, taking care not to transect the native follicles.
• Place the graft gently into the recipient site, applying light pressure for several seconds using a wet cotton-tip applicator to promote hemostasis and prevent graft extrusion or popping. 
• Apply an emollient or antibiotic ointment to the donor sites, followed by a nonadherent bandage.

Postoperative Care and Instructions

The following list includes general postoperative instructions:[2][49][50]

• Sleep with the head-end of the bed elevated 15° to 30° during the first week after surgery to minimize swelling.
• Avoid heavy lifting and strenuous activity for 1 week.
• Place ice on the forehead, not the grafts, for 20 minutes every 2 to 3 hours for the first week.
• Keep the area moist by spraying with normal saline every 2 to 3 hours for the first 2 to 3 days.
• Wash the scalp without rubbing 24 hours after the procedure, and wash daily with a neutral shampoo for the first week. Avoid direct contact with water from a high-pressure faucet or showerhead.
• Gradually transition to normal washing over the 2 weeks following surgery.
• Gently rub the donor area to remove crusts 5 to 7 days after surgery.
• Avoid fully immersing the head in water for 2 to 4 weeks.
• Wait 1 week before brushing the hair.
• Avoid hairstyling products for 2 weeks.
• Wait 1 month before cutting or dying hair.
• A clean, loose-fitting hat is acceptable immediately after surgery.
• Avoid exposing the donor and recipient sites to direct sunlight for 1 month.
• Apply minoxidil 5% twice daily to the recipient and donor areas, starting 5 to 7 days after surgery. 
• Return for suture removal within 10 to 14 days.
• Patients may resume anticoagulants, antiplatelet medications, and supplements 24 to 48 hours following surgery.

Some surgeons may prescribe postoperative antibiotics, although data supporting their routine use are limited. Patients should continue oral finasteride and low-level light therapy throughout the perioperative period and indefinitely afterward to help maximize results.[2][49][50] A wound care nurse or clinician experienced in postoperative patient care monitors the patient for potential complications, including infection and ingrown hairs. Patients should expect that shedding of the implanted hairs typically occurs after several days and may take several months to regrow. There may also be surrounding native hair loss at the donor or recipient site. This shock loss is transient, and new hairs typically appear after 3 to 6 months. Clinicians should monitor patients regularly over the next 6 to 12 months, until the implanted grafts have fully matured. Photographic documentation occurs around 6 to 12 months postoperatively.

Complications

The scalp's rich blood supply allows for quick healing and low infection rates. Nevertheless, complications exist. The following list includes potential complications of hair transplantation:

• Edema
• Graft dislodgement
• Recipient site necrosis
• Pain
• Bleeding
• Folliculitis
• Allergic reactions to topical anesthesia agents or other medications
• Local anesthesia overdosage
• Anaphylaxis
• Hiccups due to irritation of a phrenic nerve, which innervates the postauricular area
• Scalp cellulitis
• Temporary or permanent numbness of the scalp
• Scalp hypersensitivity
• Wound dehiscence
• Keloid or hypertrophic scars
• Hypopigmentation and hyperpigmentation
• Telogen effluvium
• Epidermal cysts and ingrown hair
• Infection [51][52][53][54]

Epidermal cysts and ingrown hairs, although self-limiting, may rarely trigger a diffuse inflammatory response affecting the entire graft population. Releasing entrapped hairs should hasten resolution.

Clinical Significance

Alopecia can significantly affect self-esteem and lead to social withdrawal. Hair transplantation provides a lasting solution to enhance appearance and boost confidence for individuals with pattern hair loss, hair loss resulting from injury, or those seeking hair restoration and placement as part of gender-affirming care.[2][55]

Enhancing Healthcare Team Outcomes

Hair transplantation is a surgical procedure used to restore hair in areas of thinning or baldness by relocating follicular units from a donor site, typically the occipital scalp, to recipient areas. Although most commonly performed for androgenetic alopecia, hair transplantation can also address hair loss from trauma, scarring conditions in stable phases, facial hair restoration, and hair placement as part of gender-affirming care. Techniques include follicular unit transplantation and follicular unit extraction, which are selected based on the patient's individual needs and preferences. Careful candidate selection, patient counseling, and meticulous surgical technique are essential to achieving natural, lasting results while minimizing complications and patient dissatisfaction.

Effective hair transplantation requires a coordinated, patient-centered approach that draws on the skills and strategies of the entire healthcare team. Clinicians and advanced practitioners must carefully assess candidacy, explain realistic expectations, and plan procedures that respect natural hairlines and long-term aesthetics. Hair technicians play a crucial role in tasks such as preparing and implanting hair grafts. Pharmacists contribute by reviewing medications that affect bleeding or healing, and advise on pain management and antibiotic prophylaxis. Nurses educate patients, prepare them for surgery, and provide postoperative care, making sure patients understand instructions and promptly address any complications. Patients typically need long-term oral and topical therapy to promote hair growth, increase hair density, and control the progression of hair loss. Nurses and the healthcare team play a crucial role in postoperative education, providing detailed explanations and guidance on medication, along with regularly checking in on patients' medication usage to help them adhere to their treatment. Interprofessional communication is crucial for sharing details about a patient's medical history, surgical plans, and follow-up needs, thereby preventing errors and ensuring continuity of care. Care coordination involves scheduling and managing multiple sessions if needed, arranging appropriate follow-up, and monitoring for adverse events. By collaborating effectively, healthcare professionals can deliver safe, high-quality hair transplantation that prioritizes patient goals, minimizes risks, and enhances overall satisfaction.