CME article Part II. Hair Transplantation: Surgical Technique

Design, proof-of-concept of single robotic hair transplant mechanisms for both harvest and implant of hair grafts

The design and development of a prototype for a singular robotic hair transplant system capable of harvesting and implanting hair grafts were executed in this study. To establish a proof-of-concept for hair transplant procedures involving harvesting and implantation, a test system using a spherical phantom of the scalp was selected. The developed prototype of the robotic hair transplant system demonstrates the potential to reduce the duration that grafts remain without a blood supply, thereby minimizing hair graft damage. Additionally, the overall operation time for follicular unit extraction is comparatively shorter than that of conventional systems. Results from the robot vision tests indicate an 89.6% accuracy for hair graft detection with a 4 mm hair length phantom and 97.4% for a 2 mm hair length phantom. In the robot position control test, the root mean square error was found to be 1.268°, with a standard error of the mean of 0.203°. These outcomes suggest that the proposed system performs effectively under the conditions of a spherical phantom with a 2 mm hair length and a 5 mm distance between harvests.

A randomized controlled trial on hair follicular-derived microtissue for promoting wound healing and alleviating postoperative complications after hair transplantation

BACKGROUND

Hair transplantation, particularly through follicular unit extraction (FUE), can lead to postoperative complications, such as numbness, itching, and pain in donor areas, primarily because of delayed wound healing. Efficient management of donor-site healing is crucial to mitigate these complications and improve overall patient outcomes.

OBJECTIVE

This study aimed to assess the efficacy of hair follicular-derived microtissue (HFMT) in promoting wound healing and alleviating postoperative complications in donor areas after FUE hair transplantation.

METHODS

Perifollicular tissue obtained during the trimming phase of hair transplantation was processed into HFMT and analyzed for its properties using histological and molecular techniques. In a single-blind, split-scalp study involving 98 participants, Group A received HFMT or mupirocin, whereas Group B received HFMT or no treatment. Dermatoscopic images were captured postoperatively, and visual analog scale scores were used to evaluate pain, itching, and numbness.

RESULTS

HFMT-treated donor sites in Group A demonstrated a significantly higher wound closure ratio on postoperative day 3 than mupirocin-treated sites. Pain scores for HFMT-treated sites were consistently lower on postoperative days 3, 5, and 7. Similar trends were observed for itching scores. Group B exhibited outcomes comparable with Group A.

CONCLUSION

The application of HFMT homogenates effectively accelerated wound healing and alleviated donor-site complications after FUE hair transplantation.

Strip Harvesting Follicular Unit Transplantation Versus Follicular Unit Excision: Comparing the Number of Hairs and the Ratio of Hairs to Follicular Unit

BACKGROUND

There are 2 extraction techniques for follicular units (FUs) in hair transplantation: strip harvesting follicular unit transplantation (FUT) and follicular unit excision (FUE). Currently, no extant studies have demonstrated that one technique is superior in extraction and donor area optimization for a dense result.

OBJECTIVE

This study compares the FUT and FUE techniques by evaluating the percentage of FUs with 3 or more hairs and the hairs-to-follicular-unit ratio in patients who underwent both procedures at different times.

MATERIALS AND METHODS

The medical records of patients who underwent at least 1 FUT procedure and at least 1 FUE procedure (with this being the second surgical procedure) were reviewed. The surgeries were performed in the same clinic with the same surgeon and surgical team.

RESULTS

There was a higher percentage of FUs with 3 or more hairs and a higher hairs-to-follicular-unit ratio with the FUE technique than with the FUT technique.

CONCLUSION

In FUE, surgeons tend to choose better-looking FUs with thick, plentiful hairs. Even with these results, it is impossible to declare one procedure superior because the correct indication considers multiple factors.

Risk Factors and Hazards of Recipient-Area Perifollicular Erythema After Hair Transplantation: A Multicenter Retrospective Cohort Study

BACKGROUND

Recipient-area perifollicular erythema (RPE) may delay graft growth after hair transplantation. However, there is currently a lack of observational clinical studies of RPE.

OBJECTIVE

To study the clinical features and risk factors associated with RPE while analyzing its correlation with graft growth.

METHODS

We conducted a multicenter retrospective cohort study between June 2020 and January 2023.

RESULTS

A total of 1090 participants were included, 178 (16.33%) showed mild RPE, 56 (5.14%) showed moderate RPE, and 10 (0.92%) showed severe RPE. Patients with RPE had severe hair shaft shedding (P < 0.001) and a lower survival rate (P < 0.001) of grafts. Logistic regression analysis showed that folliculitis is a significant risk factor for mild RPE (OR 6.061, 95% CI 3.343-10.991, P < 0.001) and moderate RPE (OR 3.397, 95% CI 1.299-8.882, P = 0.013). Besides, untimely first postoperative hair washing was associated with the development of moderate RPE (OR 0.724, 95% CI 0.553-0.947, P = 0.018) and severe RPE (OR 1.553, 95% CI 1.156-2.086, P = 0.003).

CONCLUSION

RPE is a postoperative complication closely related to high hair shaft shedding proportion and low graft survival rate. Both postoperative folliculitis and untimely first postoperative hair washing may induce the occurrence of RPE.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Evaluation of hair transplantation for improving unnatural hairlines after laser hair removal: A multicenter retrospective study

CONTEXT

Laser hair removal treatment for hairlines with an unsatisfactory appearance often leads to an unnatural appearance; however, few studies have reported treatment outcomes.

OBJECTIVE

To explore the satisfaction rate of laser hair removal involving the hairline.

DESIGN

Retrospective analysis.

SETTING

Data from 5 clinical institutions.

PATIENTS

Patients (915; 630 female and 285 male) who underwent laser hair removal.

INTERVENTIONS

Issues associated with hair removal were classified, and their proportions were calculated. Hair transplantation was performed to improve the appearance of different hairline issues.

MAIN OUTCOME MEASURES

Relevant indicators of hair transplantation and postoperative effects.

RESULTS

Overall, 82 patients were unsatisfied with their hairline appearance; of these patients, 58 underwent hair transplantation to improve the hairline. Additionally, demographic statistics showed that 68% and 32% of patients were in the 20 to 30 and 30 to 40 years age groups, respectively; there were no patients in the 40 to 50 years age group. Among female patients who underwent hair transplantation, 25% had a poor hairline position, 64% had a stiff hairline appearance, and 11% experienced both issues. Among male patients, 50% had a stiff hairline appearance, 28% had temporal absence, and 22% experienced both issues. Surgical treatment included moving the hairline forward and rebuilding the frontal curves. All patients were satisfied with hair transplantation outcomes.

CONCLUSIONS

Laser hair removal can result in diverse types of unnatural hairlines. Hair transplantation has been proven to effectively improve the aesthetic appearance of the hairline.

Development and Prospective Applications of 3D Membranes as a Sensor for Monitoring and Inducing Tissue Regeneration

For decades, tissue regeneration has been a challenging issue in scientific modeling and human practices. Although many conventional therapies are already used to treat burns, muscle injuries, bone defects, and hair follicle injuries, there remains an urgent need for better healing effects in skin, bone, and other unique tissues. Recent advances in three-dimensional (3D) printing and real-time monitoring technologies have enabled the creation of tissue-like membranes and the provision of an appropriate microenvironment. Using tissue engineering methods incorporating 3D printing technologies and biomaterials for the extracellular matrix (ECM) containing scaffolds can be used to construct a precisely distributed artificial membrane. Moreover, advances in smart sensors have facilitated the development of tissue regeneration. Various smart sensors may monitor the recovery of the wound process in different aspects, and some may spontaneously give feedback to the wound sites by releasing biological factors. The combination of the detection of smart sensors and individualized membrane design in the healing process shows enormous potential for wound dressings. Here, we provide an overview of the advantages of 3D printing and conventional therapies in tissue engineering. We also shed light on different types of 3D printing technology, biomaterials, and sensors to describe effective methods for use in skin and other tissue regeneration, highlighting their strengths and limitations. Finally, we highlight the value of 3D bioengineered membranes in various fields, including the modeling of disease, organ-on-a-chip, and drug development.

Evaluation of a Novel Graft-Holding Solution in Hair Transplantation: A Randomized Controlled Clinical Study

BACKGROUND

Hair transplantation has become a popular choice for alopecia treatment; however, postsurgical hair shedding still annoys both patients and surgeons.

OBJECTIVE

To explore the impact of graft-holding solution on postsurgical hair shedding and testify the protective efficacy of histidine-tryptophan-ketoglutarate solution with adenosine triphosphate and deferoxamine (HTK-AD).

METHODS

There were 240 patients enrolled in the study, and the follicles were placed into either HTK-AD or Ringer solution (RS). Masson staining and live/dead staining were performed to evaluate graft morphology and apoptosis levels, respectively. The between-group comparison of postsurgical graft shedding, survival rate, complications, and patient satisfaction was performed.

RESULTS

Grafts in HTK-AD maintained organized dense collagen construction and higher cell viability, but those preserved in RS became soft, which hindered implantation. Histidine-tryptophan-ketoglutarate solution with adenosine triphosphate and deferoxamine significantly reduced the incidence of postsurgical hair shedding (73.81% vs 95%), delayed shedding onset, and diminished shedding amount versus RS ( p < .05) when ≥3,000 grafts were transplanted. The shedding duration was shortened, and hair regrowth started earlier in HTK-AD versus RS ( p < .05); thus, satisfaction was increased. The final survival rate showed no difference between 2 groups.

CONCLUSION

Histidine-tryptophan-ketoglutarate solution with adenosine triphosphate and deferoxamine is superior to RS for hair graft preservation because it improves graft viability and alleviates postsurgical shedding.

Relieving postoperative pain using tumescent solution with ropivacaine in follicular unit excision

BACKGROUND

Local tumescent anesthesia relieves postoperative pain.

OBJECTIVE

To compare the effect of injecting a tumescent solution with/without ropivacaine on postoperative pain.

METHODS

A randomized, double-blind control study was conducted in 314 patients who underwent first follicular unit excision after obtaining informed consent and ethics committee approval. The patients were randomly divided into three groups: intra-groups (group 1, injected with tumescent solution with ropivacaine; group 2, without ropivacaine) and inter-group (group 3, right-head/left-head side with/without ropivacaine). Postoperative pain was recorded using the 5-point Wong-Baker Faces Pain Scale. No preoperative analgesic was administered to any patient. The survival rate of hair follicles was measured using dermoscopy during follow-up. Data were statistically analyzed.

RESULTS

Of the 314 patients included in the study, 166 were men and 148 were women with a mean age of 32.15±4.58 (range, 25-45) years. Postoperative pain with ropivacaine was significantly more relieved compared to that without ropivacaine in both groups (P<0.05). There was no significant difference between sex and survival rate of hair follicles in the intra- or inter-group.

CONCLUSION

A tumescent solution with ropivacaine has proven to relieve postoperative pain and is a safe and valuable form of local anesthesia in follicular unit excision.