The MD-medical doctorate or mandatory doctorate?

The introduction in the UK of the Calman Registrar training scheme envisaged seamless progression from Senior House Officer (SHO) grade through to Consultancy. Within this framework research was acknowledged to be a valuable (but optional) part of the training programme, as laid out by the 'Orange Guide' to Specialist Registrar (SpR) Training [A Guide to Specialist Registrar Training 1998; HM Press]. Time is provided for this activity within the SpR training scheme, but it is becoming increasingly evident that the majority of formal research (towards post graduate degrees) is being carried out by so-called 'gap' SHO's in order to gain entry into Higher Surgical Training (HST) programmes [Ann R Coll Surg Engng 81 (1999) 182], [Br J Plast Surg 55 (2002) 463-468]. With this in mind, a survey of all Plastic Surgery SHO's in the UK was undertaken to assess the extent of clinical research undertaken by individuals, and the perceived need for formal research for career progression.

Synovial sheath cell migratory response to flexor tendon injury: an experimental study in rats

PURPOSE

We aimed to investigate the degree of participation of synovial sheath cells in the process of tendon healing by selective cell labeling and direct observation of migrational pathways.

METHODS

We designed a novel rat animal model that employed vital dye staining of synovial sheath cells. The flexor digitorum profundus (FDP) tendon was removed from its sheath and vital dye was applied directly to the synovial sheath cells. A window was cut in the removed tendon before being returned to the sheath, thus placing a tendon injury adjacent to the labeled synovial sheath cells. The synovium remained intact at all times, and labeling was confirmed to be localized to the synovium. The migrational response of the synovial sheath cells to the tendon injury was observed by harvesting the tendons at 1, 3, 5, and 7 days (n = 6 for each time period) after injury and assessing tendon response with frozen sections under ultraviolet microscopy.

RESULTS

Labeled synovial sheath cells were observed within the substance of the healing tendon 24 hours after injury, with numbers increasing with time for up to 5 days, but decreasing by day 7.

CONCLUSIONS

This study confirms that in the rat model synovial sheath cells move into the healing tendon area and then migrate into the tendon core.

Mapping of vascular endothelium in the human flexor digitorum profundus tendon

PURPOSE

Previous techniques to delineate the human flexor digitorum profundus (FDP) vasculature have been innovative but potentially imprecise, resulting in uncertainty as to the existence of avascular zones in the flexor tendon. We aimed to use a novel immunohistochemical technique to determine more accurately the vasculature of the human flexor tendon.

METHODS

Thirty fresh cadaveric human FDP tendons were harvested, fixed, wax embedded, sectioned, and stained using the anti-CD31 monoclonal antibody to allow vessel visualization. Vessel numbers and vascularity density ratios were determined by computed image analysis.

RESULTS

Vessel density ratios varied with anatomic location, with a decrease between the A2 and A4 pulleys. There also was variation in vascularity ratios in the anteroposterior plane, with the palmar surface of the tendons having a lower vessel density.

CONCLUSIONS

We have shown that although areas of low vascularity exist on the palmar aspect of the tendon, there are no truly avascular zones.

The different characteristics of Dupuytren's disease fibroblasts derived from either nodule or cord: expression of alpha-smooth muscle actin and the response to stimulation by TGF-beta1

Mechanisms behind the onset and progression of Dupuytren's disease are poorly understood. Both myofibroblasts and transforming growth factor beta 1 (TGF-beta(1)) have been implicated. We studied fibroblast cultures derived from nodules or cords of Dupuytren's contracture tissue to determine the proportion of myofibroblasts present in comparison with flexor retinaculum fibroblast cultures. We identified myofibroblasts by immunohistochemical staining for alpha-SMA. We then investigated the effects of TGF-beta(1) stimulation on these fibroblasts. Basal myofibroblast/fibroblast proportions were 9.7% in nodule cell cultures, 2.7% in cord cell cultures and only 1.3% in flexor retinaculum cell cultures. Nodule and cord myofibroblast proportions increased to 25.4% and 24.2%, respectively, in response to TGF-beta(1) treatment. Flexor retinaculum cell cultures showed no response to TGF-beta(1) stimulation. Fibroblasts cultured from specific regions of Dupuytren's tissue retain myofibroblast features in culture. TGF-beta(1) stimulation causes an increased myofibroblast phenotype to similar levels in both nodule and cord, suggesting that previously quiescent cord fibroblasts can be reactivated to become myofibroblasts by TGF-beta(1). This could be an underlying reason for high recurrence rates seen after surgery or progression following injury.

The early surface cell response to flexor tendon injury

PURPOSE

The migratory response of surface fibroblasts to flexor tendon injury was studied by their selective labeling with a vital dye.

METHOD

The surfaces of 30 rat deep flexor tendons were bathed in 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine percholate (DiI), a vital dye for 5 minutes. The residual dye was removed by thorough irrigation. A partial tenotomy was made in the stained section by cutting out a central window. Semiquantitative cell counts and position of stained fibroblasts were noted by examination under fluorescent light at 0, 1, 3, 5, and 7 days.

RESULTS

The surface fibroblasts readily took up the vital dye at day 0. By day 1 dyed cells had moved into the cut. By day 3 they had migrated laterally into the core substance of the tendon. Core dyed cell counts at days 1, 3, 5, and 7 were significantly different compared with day 0 core dyed cell counts.

CONCLUSIONS

This cell migration from the surface of the cut to the tendon core is likely to be vital in the early stages of tendon healing.

A prospective review of open central slip laceration repair and rehabilitation

A prospective review was carried out to evaluate the outcome of surgically repaired open central slip (zone III) injuries which were treated with 3 weeks of proximal interphalangeal joint immobilization within a cylinder splint and then with 3 weeks of controlled mobilization within a Capener coil splint. Thirty-one fingers in 27 patients were assessed by the same independent therapist. All fingers achieved an excellent or good recovery with a mean proximal interphalangeal joint flexion of 94 degrees (range 70-110 degrees) and a mean distal interphalangeal joint flexion of 57 degrees (range 30-81 degrees). Extension deficits of the proximal interphalangeal joint were noted in five fingers (mean 6 degrees, range 3-15 degrees). The results show that a combination of immobilization and controlled mobilization is an effective rehabilitation regime for surgically repaired open central slip injuries.

The c-myc oncogene: use of a biological prognostic marker as a potential target for gene therapy in melanoma

The c-myc oncogene has been shown to be overexpressed in a number of malignancies, and may play an important role in the pathogenesis of malignant melanoma. Previous prognostic studies have demonstrated c-myc overexpression in a range of cutaneous melanomas, and levels of c-myc oncoprotein expression have been shown to correlate with clinical outcome in both primary and secondary disease. The purpose of this study was to investigate the in vitro manipulation of c-myc expression using antisense oligonucleotides. The human melanoma cell lines A375M, Be11 and WM115 were treated with c-myc antisense oligonucleotides, and the cellular growth was compared with controls. Antisense oligonucleotides reduced the growth rate of all three cell lines, and produced a reduction in c-myc gene expression as measured by flow cytometry. The growth inhibitions in the A375M, Be11 and WM115 cell lines at 72 h were 36.6%, 35.8% and 29.3%, respectively. Each of these was significantly different from control cultures (P<0.01). The c-myc antisense produced a mean 75% reduction in c-myc oncoprotein expression when compared with controls in the A375M cells (P<0.001), a 49% reduction in the Be11 cells (P<0.001) and a 28% reduction in the WM115 cells (P=0.005). This study demonstrates the importance of the c-myc oncogene in controlling melanoma growth. It suggests that blocking the expression of this gene, using an antisense approach, reduces melanoma cell growth, and may potentially provide a novel gene-therapy strategy for the treatment of advanced melanoma.

Long-term results of facial rejuvenation by carbon dioxide laser resurfacing using a quantitative method of assessment

Carbon dioxide laser resurfacing has been widely reported as an effective method for treating facial rhytides. Few published series, however, have assessed the long-term results of this procedure. We prospectively reviewed our long-term results of perioral CO(2) laser resurfacing using an accurate, reproducible and quantitative method of evaluation. Wrinkle depth was measured using a silicone elastomer to provide an exact negative-replica mask of the perioral region. Simple light microscopy was then used to measure the depth of rhytides. This was carried out preoperatively, 6 weeks postoperatively and 2 years postoperatively, and the results were compared for 31 patients. CO(2) laser resurfacing achieved a highly significant mean reduction in wrinkle depth at 6 weeks of 91% (paired t -test:P <0.00001), and this was well maintained at 2 years, when the mean reduction in wrinkle depth was 87% (paired t-test: P<0.00001). During the long follow-up, complications were few, with transient erythema being the most common; there were no cases of scarring. As in other series that have reported longer follow-up, we encountered three cases of minor hypopigmentation. We have used light microscopy on silicone moulds as an accurate method of assessing outcome after laser resurfacing of perioral rhytides. The early highly significant reduction in wrinkle depth was maintained at 2 years with minimal associated short-term or long-term morbidity.

Silicone arthroplasty for trapeziometacarpal arthritis

Twenty-three patients who had undergone trapeziectomy and Helal silicone rubber ball interposition for trapeziometacarpal arthritis were reviewed. The average age at operation was 63 (range 48-84) years and the mean follow-up was 59 (range 12-138) months. Of the 23 patients reviewed, two had pain at rest and four had some discomfort on exertion. Mean post-operative thumb extension was 37 degrees whilst mean palmar abduction was 40 degrees. Mean post-operative grip strength was 19 kg and thumb-pinch strength was 4.0 kg, 77% and 78% of the age- and sex-matched normal values. There were no cases of prosthetic dislocation, prosthetic fracture or silicone synovitis.

Long-term prospective follow-up of botulinum toxin treatment for facial rhytides

Some wrinkles and unsightly facial expressions are due to hyperactivity of the underlying facial musculature. Clostridium botulinum type A exotoxin reversibly paralyzes selected muscles and is a safe, helpful adjunct to many other treatments for facial rejuvenation. Fifty-two patients were treated and all data recorded in a prospective fashion. Only areas requested by the patient were treated. The dosage and dilution given in each area were carefully noted and all patients had pretreatment and posttreatment photographs. The effect of botulinum toxin injections on the horizontal brow rhytides was recorded by measuring the distance from the frontal hairline to the superior edge of the eyebrow in the mid-pupillary line. Patients were followed for one to three years (mean 16.3 months). One patient was not responsive to botulinum toxin in spite of repeated injections. Three further patients required touch-up injections two weeks after the initial treatment due to a weak initial response. Repeat injections were required every three to six months (mean 4.05) to maintain the desired improvement. Asymmetry of the brow was seen in two patients and corrected with further administration of botulinum toxin. Twenty-five patients had their forehead rhytides injected and the appropriate measurements taken. Brow ptosis occurred in 22 of the 25 patients and varied 1-6 mm with a mean value of 2.3 mm. This difference was statistically significant (paired t-test p <0.001). Two patients reported dryness and flakiness of the frontal area after injections. No cases of eyelid ptosis or hypersensitivity were seen. Botulinum toxin injections are safe and all undesired effects are reversible. Great care has to be taken not to aggravate the degree of brow ptosis. Injection of the forehead depressors minimizes the risk of brow ptosis. Careful planning of injection sites and doses avoids a mask-like upper face. The use of botulinum toxin provides a useful adjunct to laser and surgical procedures for facial rejuvenation.

The long-term results of ruby laser depilation in a consecutive series of 346 patients

The goal of this study was to prospectively assess the long-term results of ruby laser depilation in 346 consecutive patients who underwent hair removal at 402 anatomical sites. The patients were treated using a ruby laser, with mean power ranging from 8.6 J to 15.7 J according to skin type. Results were assessed using two outcome measures-the percentage reduction in hair density and the hair-free interval. The median reduction in hair density was 55 percent (range, 0 to 100 percent) at a median time of 1 year after the last treatment session. The median hair-free interval was 8 weeks. Patients underwent a median number of four treatment sessions. Forty-three of the 346 patients were treated at more than one anatomical site. Of the sites treated, 75 percent reduction in hair density was achieved in 22 percent, 90 percent reduction was achieved in 2.2 percent, and complete depilation was achieved in only 0.7 percent. Darker colored hair was more effectively treated. Treatment efficacy was not affected by anatomical site, with the exception of the faces of male patients, which were found to be particularly resistant to treatment. There was a significant correlation between the number of treatments given and the outcome. The overall complication rate was 9.0 percent (36 of 402 sites) with respect to pigmentary changes and blistering, but varied according to Fitzpatrick skin type. The complication rate was highest in skin types V and VI (24.7 percent), with no complications in skin type I. Although a greater than 50 percent reduction in hair density was achieved in half of the 346 patients treated, complete depilation was achieved in only an extremely limited number of patients.

The role of human-derived fibrin sealant in the reduction of postoperative flexor tendon adhesion formation in rabbits

This study assessed the role of a novel fibrin sealant (Vivostat in adhesion reduction after flexor tendon surgery. The deep flexor tendons of the 2nd and 4th digits of the left paw of 20 rabbits were exposed and a standard partial injury was performed on each. The rabbits were randomized to either immediate post-injury treatment with Vivostat or no treatment. In each case active movement of the 2nd digit was prevented while the 4th digit was allowed to move normally. The two groups were assessed at 14 days for adhesion formation with a tensiometer. The right paw acted as the unoperated control. Results showed that there was no significant difference in the force needed to remove the tendon from its sheath when comparing the two Vivostat((R))-treated groups to the unoperated controls. There was, however, a highly significant difference in this force between the non-Vivostat-treated groups and the unoperated controls. This suggests a beneficial effect of Vivostat in reducing post surgical tendon adhesion formation.

Long-term results of digital arthrodesis with the Harrison-Nicolle peg

This study determined the long-term success of digital arthrodesis with the Harrison-Nicolle peg. We reviewed 90 digital joints in 60 patients fused with the peg between 1986 and 1998 at a mean follow-up of 6 (range 2-11) years. The prime indication for surgery was rheumatoid arthritis. The early complication rate was 8%. At 1 month 89% of joints were pain-free and stable. In the long-term follow up, 96% of the joints were pain-free and stable, with the original angle of fusion. 85% achieved bony fusion, with no clinical difference between bony and fibrous fusion. Overall there was a significantly higher complication rate in the distal interphalangeal joint. We conclude that, with the exception of the distal interphalangeal joint, the Harrison-Nicolle peg is extremely effective for digital arthrodesis in the rheumatoid patient.

The prognostic importance of c-myc oncogene expression in head and neck melanoma

Melanomas of the head and neck have a poorer prognosis than melanomas arising at other cutaneous sites. To study the biology of this disease, the expression of the c-myc oncogene was studied in tumors from 97 patients with head and neck melanoma using the technique of flow cytometry. Survival analysis revealed that stratification of patients according to oncogene expression provided a prognostic marker with shorter overall survival in tumors with high nuclear c-myc oncoprotein positivity (log-rank test, chi2 = 8.77, p < 0.005). Multifactorial analysis using Cox's proportional hazards model revealed nuclear c-myc oncoprotein to be an independent prognostic marker (log-rank test, chi2 = 8.82, p = 0.005). These results support the authors' previous studies of the prognostic value of c-myc expression in melanoma and suggest that estimation of c-myc oncoprotein may be of clinical importance in identifying high-risk patients.

Flexor tendon blood vessels

The aim of this study was to assess rabbit long flexor tendon vascularity in a qualitative and quantitative manner using immunohistochemistry. The endothelial cell surface marker CD31 was targeted with a specific monoclonal mouse-anti-human antibody with good species cross-reactivity. Subsequent signal amplification and chromogen labelling allowed vessel visualization. Computer image analysis was performed. Values for vessel number and total vessel area per section, as well as the sections' cross-sectional tendon areas, were obtained. There was a consistent deep tendon avascular zone between the A2 and A4 pulley in the rabbit forepaw. This was not the case in the hindpaw, with dorsally orientated longitudinal vessels coursing the length of the intrasynovial tendon. The area of least vascularity in the hindpaw was around the metacarpophalangeal joint. We therefore recommend the use of hindpaw tendons when using the rabbit as a flexor tendon experimental model. This is because its vascular pattern is similar to that of the human flexor digitorum profundus.

Reducing postoperative morbidity after the insertion of gold weights to treat lagophthalmos

Paralysis of the orbicularis oculi muscle leads to an unopposed action of the levator of the upper eyelid (lagophthalmos) in facial nerve palsy. The resultant exposure of the cornea may lead to keratitis, corneal ulceration, and eventual blindness. Although many surgical options exist in the treatment of lagophthalmos, upper lid loading with a gold weight implant has become one of the preferred methods to reduce the complications that may follow. The problems encountered after gold lid loading and methods to reduce postoperative morbidity are not well documented. The objective of this study was to determine the range of morbidity seen after gold weight insertion and to evaluate the effect of supratarsal fixation on subsequent morbidity. After retrospective reviews by questionnaire and case note analysis, supratarsal fixation was found to noticeably reduce the rate of implant ulceration and extrusion. This study demonstrates upper lid loading to be an effective method for the treatment of lagophthalmos, and it supports fixation of gold weights in reducing surgical morbidity.

The Merkel cell carcinoma: survival and oncogene markers

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and malignant tumour. Survival data and prognostic factors are scarce.

AIM

To investigate the usefulness of biological markers to predict the prognosis for these aggressive tumours.

METHODS

C-myc oncoprotein and proliferation was analysed in specimens from 13 patients with MCC, treated between 1983 and 1997. The average age at presentation was 68.3 years. Overall follow-up ranged from 14 to 158 months, with a mean of 68.2 months. Specimens were analysed by immunohistochemistry for proliferation (mib-1) and flow cytometry for oncogene activity (c-myc).

RESULTS

The median positivity was 52% for the c-myc oncogene and 50% for proliferation, but these did not correlate to survival as analysed by the Kaplan-Meier method. Other parameters such as median age at presentation, sex, site of tumour and adjuvant radiotherapy were also analysed, but none were found to be significant.

CONCLUSIONS

This study showed that neither c-myc oncogene activity or mitotic index in MCC can be related to patient survival.

The abnormal nucleus as a cause of congenital facial palsy

BACKGROUND

Congenital facial palsy (CFP) is clinically defined as facial palsy present at birth. It is associated with considerable disfigurement and causes functional and emotional problems for the affected child. The aetiology of the majority of cases however, remains elusive.

AIMS

To investigate the role of a neuroanatomical abnormality as a cause of unilateral CFP.

METHODS

Magnetic resonance imaging (MRI) scans were performed on 21 patients with unilateral CFP. Fifteen patients had unilateral CFP only; six suffered from syndromes which can include unilateral CFP.

RESULTS

Of the 15 patients with unilateral CFP only, four (27%) had an abnormal nucleus or an abnormal weighting of this area on the MRI scan, compared to one (17%) of the remaining six patients.

CONCLUSION

Developmental abnormalities of the facial nucleus itself constitute an important, and previously ignored, cause of monosymptomatic unilateral CFP.

Paralysis of the marginal mandibular branch of the facial nerve: treatment options

Isolated paralysis of the marginal mandibular branch of the facial nerve results in an asymmetrical smile with elevation of the lower lip on the affected side. We discuss the surgical options for its correction and present a series of 26 patients who underwent either botulinum toxin injection, anterior belly of digastric transfer or free extensor digitorum brevis transfer as treatment. Botulinum toxin injection provided satisfactory results although these were temporary. Anterior belly of digastric transfer was the surgical procedure of choice. It yielded superior cosmetic results, less donor-site morbidity and required a shorter operating time. In more complex congenital facial hypoplastic syndromes, or following extensive surgery in the digastric triangle, the anterior belly of the digastric muscle may be absent or damaged. Extensor digitorum brevis transfer is the preferred option in these cases.

Chronic axillary hidradenitis--the efficacy of wide excision and flap coverage

A number of different modalities of surgical treatment for axillary hidradenitis suppurativa have been suggested. This study compares three different methods of surgical excision. Fifty-nine patients (94 axillae) were treated over a 14-year period. There were 42 females and 17 males with an average age of 32 years (range 16-65 years). Twenty-six axillae had excision of only the diseased skin and recurrent disease occurred in seven. However, in 39 axillae that were treated by excision of all the hair bearing skin, only three developed recurrent disease, which is a significant reduction in the incidence of recurrent disease (P = 0.04, Fischer's exact test). Twenty-nine axillae were treated by wide local excision (2 cm beyond the hair bearing skin) and no recurrence occurred. However, there was no statistical difference (P = 0.18, Fischer's exact test) in disease recurrence between excision of all the hair bearing skin and wide local excision. This study suggests that excision of all the hair bearing skin is the preferred method of surgical treatment. Flap coverage was an effective method to achieve wound closure after adequate excision and can be achieved by random fasciocutaneous flaps for small or medium sized defects and parascapular flaps for large defects.

Can the carbon dioxide laser completely ablate basal cell carcinomas? A histological study

Carbon dioxide laser ablation has been advocated as an alternative therapeutic modality for basal cell carcinoma. This study examined the limitations of carbon dioxide laser ablation for BCCs by the formal excision and histological examination of the tumour bed, following laser therapy. We evaluated the tumour type and ablation depth required to ablate the tumours completely. Fifty-one selected BCCs, ranging from 4 to 35 mm, were ablated with a carbon dioxide laser combined with a microprocessor controlled optomechanical flash scanner. Clinically there were 21 superficial, 28 nodular and 2 infiltrative types. Complete ablation at the deep margin was associated with ablation depth (P = 0.006) and with tumour type (P = 0.01). Overall, all tumours of superficial subtype (found most commonly on the trunk) could be completely ablated reliably, provided they were lasered to a depth of the middle dermis or deeper. In contrast, nodular tumours could not reliably be ablated by this method. A small subset of nodular tumours less than 10 mm diameter, however, were all completely ablated provided they were lasered to a depth of the lower dermis or deeper, however this may result in delayed healing and scarring. We conclude that this fast modality is useful for the treatment of some BCCs provided strict selection criteria are met. Laser ablation would be most beneficial for patients with multiple superficial BCCs.

The effect of 5-fluorouracil on Dupuytren fibroblast proliferation and differentiation

INTRODUCTION

Dupuytren's disease is a proliferative disease with contractile properties, prone to recur after surgery. Intra-operatively applied 5-fluorouracil has been used to avoid scar problems in the eye after glaucoma filtration surgery and was therefore investigated as a means to inhibit proliferation and myofibroblast differentiation in Dupuytren fibroblasts in vitro.

METHOD

Primary cell lines were obtained by explants from Dupuytren's tissue (n = 6), non-diseased palmar fascia from patients with Dupuytren's disease (n = 3) and carpal ligament from patients undergoing carpal tunnel release (n = 3). The effect of 5-fluorouracil on proliferation was assessed by cell counting. Myofibroblast differentiation, an intergral part of Dupuytren's contracture, was investigated by staining for alpha smooth muscle actin, a marker for contractile cells, using immunohisto-chemical methods.

RESULTS

A single exposure to 5-fluorouracil caused a sustained inhibition of proliferation in Dupuytren's and non-diseased fascia cultures, whilst the effect on carpal ligament cultures was transient. Untreated Dupuytren's fibroblasts exhibited the highest myofibroblast differentiation, whilst differentiation in non-diseased fascia cultures was shown to be proportional to cell density and virtually non-existent in carpal ligament cultures. After 5-fluorouracil exposure, the differentiation was significantly reduced in Dupuytren's fibroblasts cultures, reduced at high cell densities in non-diseased fascia and unchanged in carpal ligament cell cultures.

DISCUSSION

5-fluorouracil inhibits both proliferation and myofibroblast differentiation in Dupuytren's cell cultures and may have a potential use as an adjuvant treatment to Dupuytren surgery in order to reduce the rate of recurrence and contracture.

An analysis of p16 tumour suppressor gene expression in acral lentiginous melanoma

Acral lentiginous melanoma is a particularly aggressive melanocytic lesion but, due to its comparative rarity, biological investigations into the behaviour of this subtype of melanoma are lacking. The activity of the recently described p16 tumour suppressor gene, thought to be the 'familial melanoma gene', was studied in 24 patients with subungual melanoma and 44 patients with plantar melanoma. Lower levels of p16 oncoprotein were demonstrated than that found in other histogenetic types of melanoma. Stratification of patients of all disease stages revealed a poorer survival in patients with low p16 expression (log rank test, chi(2)= 3.9, P = 0. 05). These data suggest that p16 inactivation may play an important role in the development and progression of acral lentiginous melanomas. However, the level of p16 expression was not prognostic since survival analysis on stratification of stage I patients according to p16 level did not reach statistical significance for both survival and disease free interval.

Ruby laser-assisted hair removal: an ultrastructural evaluation of cutaneous damage

Ruby laser-assisted hair removal is thought to act via selective photothermolysis of melanin in the hair follicles. Although initial clinical trials of permanent hair removal using ruby lasers are promising, the exact mechanisms of hair destruction and the potential damage to other structures of skin are not known. The aim of this study was to evaluate the cutaneous ultrastructural changes following ruby laser hair removal. Nineteen healthy Caucasian patients with dark (brown/black) hair were treated with the ruby laser and biopsies taken after 0, 2, 3, 5, 7, 14 and 21 days. Specimens were examined by light and electron microscopy. Laser-treated specimens showed widespread coagulation and charring of subcutaneous hair shafts. These obviously damaged follicles were randomly dispersed amongst intact follicles within the same treatment sites. Microscopic changes were also seen in the basal epidermis where melanin was concentrated, irrespective of any obvious macroscopic damage. A low level of inflammatory response seen up to 2 weeks after treatment always followed laser treatment. Suprabasal epidermal necrosis was only seen in patients with blister formation after treatment. Ruby laser irradiation results in selective damage to the hair follicles, with microscopic changes to the basal epidermis. The damage is probably compounded by the inflammatory response to the damaged hair. The normal appearance and distribution of collagen in the dermal layer supported the clinical evidence that laser-assisted hair removal, if performed correctly, does not lead to scar formation.

The effect of ruby laser light on cellular proliferation of epidermal cells

In ruby laser-assisted hair removal, microscopic damage is often seen in the basal epidermal cells, where melanosomes are concentrated. It is not known whether this treatment leads to cellular hyperproliferation. It was the aim of this study to investigate this. Ten white patients were treated with the Chromos 694-nm Depilation Ruby Laser, and biopsies taken before and after treatments to assess the presence of cell hyperproliferation, which normally accompanies epidermal damage, with immunohistochemical staining of keratin 16 and Ki67. No evidence of cell hyperproliferation was seen in all specimens examined after ruby laser irradiation. The authors conclude that despite the possible microscopic damages seen in the basal epidermis after laser hair removal, there is no evidence of cellular hyperproliferation. This is in contrast to ultraviolet-irradiated cell damage, in which increased basal cell turnover is seen.