The Foot 20 (2010) 12–17

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A comparison of electrosurgery and sharp debridement in the treatment of chronic neurovascular, neurofibrous and hard corns. A pragmatic randomised controlled trial

J.S. Bevans ∗, G. Bosson

Department of , Manchester Community Health, NHS Manchester, Mauldeth House, Mauldeth Road West, Chorlton, Manchester M21 7RL, UK article info abstract

Article history: A randomised controlled trial was undertaken to compare treatment outcomes for neurovascular, neu- Received 22 September 2008 rofibrous and hard corns. Patients with suitable lesions were referred from community clinics within Received in revised form 26 July 2009 Manchester PCT. Fifty-nine subjects were enrolled into the study and randomised to one of two treat- Accepted 11 March 2010 ment groups; group (a) those treated with electrosurgery and (b) a control group treated with standard sharp debridement. The principle outcome measure was the Visual Analogue Scale (VAS) pain score (0, Keywords: no pain; 10, worst pain experienced) and lesions were categorised as demonstrating no change, partial or Podiatry complete resolution. Data were analysed using ‘Intention to Treat’ methodology, i.e. analysis of data from Chiropody n n Corns subjects randomised to each group (electrosurgery group = 34; control group = 25). The results show p Neurovascular corns a statistically significant reduction in pain in group (a) as reported at the 6 month review ( = 0.0001) Electrosurgery with a complete and partial resolution rate of 26% and 50%, respectively compared with group (b) whose Sharp debridement pain level reduction was not significant and which showed resolution rates of 4% and 28% only. Visual Analogue Scale © 2009 Elsevier Ltd. All rights reserved. Intention to Treat analysis

1. Introduction was frequently unsatisfactory as removal of sufficient tissue was impossible because of the pain involved [2]. The lesions were also Hard corns (heloma durum), defined as localised areas of thick- found to be generally unresponsive to treatment with orthoses. It ened epithelial stratum corneum containing a nucleus of keratin, is likely that there are a variety of reasons for this; for example, frequently develop at sites of increased or abnormal forces (notably inappropriate footwear or the orthosis may have been unsuitable, intermittent compressive stresses and friction) acting on the skin. poorly prescribed, fabricated or fitted, i.e. not modifying the exces- Long-standing corns can be complicated with the invasion of nerve sive stresses on the tissues occurring at the site of the lesions; such fibres and blood vessels (neurovascular corns) and can become stresses being the most likely primary aetiological factor in their dense and fibrous (neurofibrous corns) causing considerable pain development, prolongation and deterioration. which has a significant effect on the activities of daily living of the Prior to undertaking the study, patients were being referred for patient. In practice it may be difficult to distinguish between differ- electrosurgery. The lesions treated were generally of long-standing, ent categories or types of lesion but because of the pain involved, many of very long duration, which had been resistant to conserva- they are difficult and unrewarding to treat and often require a high tive treatments and which required frequent visits to the clinic. frequency of treatment [1]. The problems caused by such lesions The electrosurgery was generally well received but without formal have been experienced by a proportion of the podiatric patient pop- evidence reports of improved treatment successes and the associ- ulation in Manchester. It was found by the research team that, in ated enhanced patient well-being would remain anecdotal. It was the majority of the subjects referred to the study by podiatrists, decided therefore to undertake a research study to evaluate the the treatment most frequently received by patients with these technique in which a null hypothesis could be tested in order to lesions was scalpel debridement, augmented in a proportion of demonstrate effectiveness and improved patient outcomes. cases with an orthosis. However, it was reported that treatment Electrosurgery in a variety of forms (desiccation, fulguration, coagulation) has been used in a range of medical (, , , proctology, urology) and other spe-

∗ cialisms for many years. The ‘Hyfrecator’ is widely used in this Corresponding author at: Department of Podiatry, Newton Heath Health Centre, context in the treatment of cutaneous conditions and allows pre- 2, Old Church Street, Newton Heath, Manchester M40 2JF, UK. E-mail addresses: [email protected], [email protected] cise destruction of superficial and deep tissues [3]. The technique (J.S. Bevans). has been adopted for the treatment of painful plantar corns and

0958-2592/$ – see front matter © 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.foot.2010.03.003 J.S. Bevans, G. Bosson / The Foot 20 (2010) 12–17 13 verrucae [4–8], but it appears that its use has been somewhat lim- the randomisation protocol and to open the next sealed envelope ited and, although there are some reports of successful outcomes in sequence in order to ascertain the group – (a) electrosurgery or there remains a lack of evidence in the literature for its efficacy. In (b) control in which the subject would be included. Clearly with addition, there are concerns that the procedure may in itself cause this type of study it is impossible to blind either subject or clinician problems although there seems to be little evidence to support this to the type of intervention. Notwithstanding the information given notion. at the time of referral, some patients refused to be enrolled for ran- The process of electrosurgery, i.e. electrodesiccation, provides a domisation because they wanted to be guaranteed electrosurgery. means by which pathological tissue can be removed by the appli- Generally this was because their lesions were so painful and dis- cation of a dense electrical current via a small handheld electrode ruptive to daily activities that any chance of improved treatment which is applied to the lesion. The heat generated by the passage was immediately attractive and requested; appropriate treatment of a current desiccates the tissue, which adopts a blanched appear- was undertaken. ance thus allowing its separation and removal [4,5]. Normally the The Visual Analogue Pain Scale (VAS) was used as the main pri- lesion can be lifted away with little requirement for ‘excision’ or mary outcome measure. The scale consists of a 10 cm line on which ‘debridement’ and frequently this can be achieved with little or no ‘0’ indicates no pain and ‘10’ indicates maximum pain severity. resulting haemorrhage. Clearly, when using electrosurgical tech- The patient is instructed to indicate and mark the line at a point niques, it is important to minimise trauma and damage to tissues between the two extremes, which would indicate and represent the surrounding and deep to the lesion. If necessary, should any bleed- highest level of pain experienced from the lesion. The scale is a com- ing occur, ‘fulguration’ (where a suitable electrode is held a short monly used method for the evaluation of the experience of pain, it distance away from the tissue to produce sparking between the is easy to use, results are reproducible, it can be used in a variety of electrode and the surface) can be used as a haemostat. The effect settings, is sensitive to treatment effects and data derived from it on tissue is more superficial with fulguration than is the case with can be analysed with standard statistical techniques [11]. Sample desiccation where the electrode is in contact with the tissue. sizes of 21 per group were required in order to be sure of detect- The electrical circuit from the Hyfrecator via the hand-piece ing a statistically significant difference of 3 points (30 mm) on the probe to the lesion is completed by means of a dispersive plate VAS scale. A baseline score was recorded prior to treatment, sub- placed under the fleshy part of the patient’s leg. The plate, being jects were followed-up at intervals with the score at the 6 month relatively large in comparison to the electrode, ensures that no heat review used for analysis. This post-intervention review period was is generated at this part of the circuit. For safety reasons it is always deemed appropriate – firstly it is an accepted trial review inter- advisable to use the dispersive plate as electrical current will always val and further, it was a convenient interval for patients some of find the path of least resistance to ground to complete the circuit. whom were likely to be drawn from the large transient popula- This could be via the patient’s hand or bony prominence if it were tion of Manchester which naturally forms a proportion of patients touching a metal component of the couch or treatment trolley or seen in the podiatry department. Presenting lesions were defined unit, resulting in discomfort or even a burn depending on the power (as either hard, neurovascular or neurofibrous corns) by the partic- setting used which should always be the minimum necessary for ipating podiatrist, categorical allocation being dependent upon the the procedure [4]. appearance of the lesion and findings during treatment. The size of Electrosurgery is always carried out under local anaesthesia of lesions was not recorded. the operative site [4,6,7], plantar areas normally requiring a tibial In the planning stages of the study, advice from a statistician nerve block as a minimum. Depending on the location of the corn, suggested that pain data derived from the VAS scale can be skewed other nerve blocks or additional local infiltration are required in and that non-parametric tests should be used for analysis. However, order to obtain full anaesthesia of the area around the lesion. it is reported that parametric ‘t’ tests for two groups of subjects (and ANOVA tests for three and more groups) even without data transformations to bring the distributions closer to the normal 2. Method distribution are good tests to find differences in VAS measure- ments among groups [10,11]. With the sample sizes being relatively The North West Region R&D Support Unit based at Salford small, no assumption of normal distributions could be made; a University provided help with the study methods, sample sizes, Mann–Whitney test was therefore used for analysis and reporting a power calculation based upon preliminary work and the ran- of data with a significance level previously set at 0.05. Data were domisation procedure. Ethical approval was obtained prior to analysed utilising the ‘Intention to Treat’ (ITT) principle [12,13].At commencement of the study. final review lesions were categorised in terms of outcome as being Suitable subjects with intractable helomatous lesions were totally resolved – i.e. absence of lesion; partial resolution – defined recruited from patients attending for routine podiatry treatment at as presence of lesion with improved symptoms or unresolved – clinics and health centres across the city of Manchester and referred those lesions that displayed unchanged symptoms. Patients were to the two centres at which the study was to take place. It was made allowed unrestricted access to their podiatry clinics based on their clear to potential subjects by the referring podiatrist that referrals clinical need for dressings (the first post-operative dressing was were for participation in a research study and not for electrosurgery undertaken by the research team) and treatment during the follow- treatment per se. up period. The objective of the study therefore was to compare The study details were explained fully to each patient before electrosurgery with a standard form of treatment with the null referral and again before consent was obtained. In particular it was hypothesis to be tested being that there would be no difference explained that the type of treatment to be received as part of the in treatment outcomes. study (active intervention with electrosurgery or standard treat- Figs. 1–4 show the ‘Conmed®’ equipment used in the study and ment) would depend upon the randomising process and this would the techniques employed. not be known until after consent had been given and the process initiated. All subjects were therefore given sufficient time to make 2.1. Inclusion criteria an informed decision as to whether or not they wished to partici- pate in the research. Those who consented to take part in the study Diagnosis of chronic, long-standing painful hard, neurovascu- were included and, after consent had been obtained, the study lar or neurofibrous corns requiring frequent treatment (once per administrative officer was telephoned with a request to consult month or more). 14 J.S. Bevans, G. Bosson / The Foot 20 (2010) 12–17

Fig. 1. The Hyfrecator: Conmed® Hyfrecator 2000 (Conmed Corp. 310 Broad St, Utica, NY 13501).

Fig. 3. Removal of lesion following separation of tissue.

Those with learning difficulties, severely/mentally ill patients and any other vulnerable groups. Pregnant women.

3. Results

Fifty-nine patients were recruited for the study and, although 5 subjects were lost to final follow-up, all randomised subjects

Fig. 2. Application of electric current via probe on skin surface.

Registered with the podiatry department for a minimum of 12 months prior to inclusion in the study. Able to comply with the study, treatment and follow-up instruc- tions. Informed consent.

2.2. Exclusion criteria

Conditions that may lead to impaired tissue healing. Metal implants or prosthetic joints between the emitting elec- trode and the dispersive circuit plate (electrosurgery group). Cardiac pacemaker (electrosurgery group). Contraindications to local anaesthetics (electrosurgery group). Lack of informed consent. Non-compliance with study protocol. Under 18 years of age. Fig. 4. Appearance of operative site following removal of lesion. J.S. Bevans, G. Bosson / The Foot 20 (2010) 12–17 15

Table 1 Table 4 Characteristics of study sample. Group comparison: outcome based on lesion type.

Study sample characteristics Group comparison, resolution by lesion type

Subjects (lost to follow-up) 59 (5) Electrosurgery group Control group Age [mean (SD)] years 50 (13.5) a b c a b c Males 35 HD HNF HNV HD HNF HNV Lesion Subject ethnicity (%) Outcome Caucasian 68 Partially resolved 7 5 5 4 3 0 Afro-Caribbean 17 Totally resolved 2 4 3 1 0 0 South Asian 15 Unresolved 2 3 0 10 2 3 Lesion type [electrosurgery (control)] a HD, hard corn. Hard corn 11 (15) b HNF, neurofibrous corn. Neuro fibrous corn 12 (5) c HNV, neurovascular corn. Neurovascular corn 8 (3)

Lesion site [electrosurgery (control)] Calcaneus 5 (1) Table 4 shows further analysis of outcomes based on lesion type. Plantar metatarsal head area 25 (19) Table 5 presents a summary of results for each location at which Digital 1 (3) corns were treated in subjects comprising the electrosurgery group. Lesion duration (mean SD) months Electrosurgery 103.1 (92.5) Control 85.7(102.8) 4. Discussion

In research trials, randomisation of subjects to intervention and Table 2 control groups is undertaken in order to minimise bias in treatment Analysis of visual analogue scores for study groups. effects. In situations where there are protocol violations, e.g. where Visual Analogue Scale Scores, group comparison some subjects have not adhered to the allocated management strat- egy and those subjects are excluded from the analysis (i.e. analysis VAS 1 VAS 2 p value by treatment administered – also known as explanatory or per pro- Group tocol analysis) such analysis can be flawed and may influence the Electrosurgery 74.9 (19.2) 37.3 (31.1) 0.0001 Control 60.4 (23.8) 46.0 (28.1) 0.12 (ns) unbiased comparison which was afforded by the randomisation process. Methods by which missing data can be handled usually Data are presented as mean (SD). depend upon assumptions of outcomes though these are likely to VAS 1 represents the pre-treatment baseline pain score. VAS 2 represents 6-month post-treatment pain score. lead to spurious results. It is suggested that ‘Intention to Treat’ (ITT) analysis avoids the problems created by omitting dropouts and other non-concordant subjects which may, if not included in Table 3 the analysis, negate randomisation and lead to an overestimation in Lesion resolution frequency. clinical effectiveness. This however is a complex and controversial Group comparison, lesion resolution field and the appropriate analysis to be employed for a particular Partially resolved Totally resolved Unresolved Lost study is likely to depend on the precise research question to be investigated and the type of study and data to be analysed [12–17]. Group Electrosurgery 17(50) 9 (26) 5 (15) 3 (9) Interested readers should consult appropriate texts for a full dis- Control 7(28) 1 (4) 15 (60) 2 (8) cussion on the subject. Data are presented as number (%). In this study, subjects in the electrosurgery group (a) which were lost to follow-up and therefore unable to furnish data for analysis were assumed to have had no change to the baseline VAS score were included in the ‘Intention to Treat’ statistical analysis. They whilst those in the control group (b) were assumed to have the comprised 34 subjects in the electrosurgery group and 25 in the best possible outcome of 0 pain at final review. Treating data in control group. The characteristics of the study samples are shown in this way reduces the difference in treatment effects between the Table 1. Although some patients were treated for multiple lesions, groups and provides the most rigorous of possible outcomes from data from one lesion only per subject was included in the analy- the study for statistical analysis and therefore produces a conser- sis. Data presented in Table 2 show a significant difference in the vative estimate of the treatment effect [12]. The use of both ITT and pre- and post-intervention VAS scores in the electrosurgery group per protocol statistical analysis gave similar results in that electro- (p = 0.0001) whilst the change in pain perception in the control surgery group had significantly lower pain levels from the lesions group was not significant (p = 0.12). A comparison of the incidence treated (or, where the lesion was fully resolved, the lesion site) of lesion resolution in the two groups is given in Table 3 whilst post-operatively than did the control group subjects given standard

Table 5 Electrosurgery group: treatment outcomes by lesion site.

Electrosurgery group, resolution by lesion site

Site

Calc PD1 PMA1 PMA2 PMA3 PMA4 PMA5 Total number

Resolution Partial 1 (20) 1 (100) 0 2 (50) 4 (40) 4 (80) 5 (100) 17 Total 3 (60) 0 0 1 (25) 4 (40) 1 (20) 0 9 Unresolved 1 (20) 0 1 (100) 1 (25) 2 (20) 0 0 5

Data are presented as number (%); Calc, plantar heel area; PD1, plantar to the interphalangeal joint of the hallux; PMA, plantar metatarsal head area. 16 J.S. Bevans, G. Bosson / The Foot 20 (2010) 12–17 scalpel debridement. The reduction in pain demonstrated using the to be released and these could contain viral particles or other visual analogue scale and shown statistically (Table 2) is likely to pathogenic substances. To reduce the tendency for vapour forma- be the result of the more effective removal of helomatous tissue tion the electrodessication probe and tissues undergoing treatment and associated neurological components than is possible with nor- should be well moistened with saline to improve electrical mal sharp debridement. In practice, after administration of the local conductivity. Alternatively, it could be suggested that the high tem- anaesthetic and prior to application of the electrosurgical probe, the peratures generated form a sterile field, though in the treatment of lesion is debrided to remove as much of the pathological tissue as verrucae in particular it could be advisable to use a form of vapour possible to facilitate application of electrical current and allow finer extraction to reduce any inherent risks. judgement of the extent of desiccation produced in order to limit It has been found in electrosurgery practice that at the dermo- potential damage to healthy tissue beneath and adjacent to the epidermal junction there was often a deep invagination into the lesion. Clearly, such debridement with the benefit of local analge- dermis beneath the location of the nucleus of the lesion and this sia will be considerably more effective than standard debridement required additional application current from the electrode in order without anaesthetic but nonetheless electrosurgery enables still for it to be fully removed. The use of a pointed probe just touching further tissue removal. the tissue caused it to adhere to the probe allowing the material to The primary study outcome measure together with the inci- be pulled away leaving the deeper cavity in the dermis. A haemor- dence of total and partial resolution of lesions in the electrosurgery rhage often resulted (this could have been from prominent vascular group (shown in Table 3), suggest that electrosurgery can be effec- elements which had extended into the lesion) which was then ful- tive in the treatment of chronic helomatous lesions. These findings gurated if necessary, however the formation of the blood clot could are similar to the results of other studies [5,6] in that the rate of have assisted in the healing process. Whether this deeper area, with improvement, i.e. the proportion of subjects in the electrosurgery its increased surface area of stratum germinativum could be the group showing partial and total resolution, was high at 76% (50% cause of a hyperkeratotic lesion at the location when subjected and 26%, respectively) whereas in the control group only 32% of to compressive and/or other stresses or is an effect of a lesion’s subjects demonstrated similar levels of resolution. The anomalous presence is open to speculation. finding that one lesion (4%) in the control group given standard The requirement for local anaesthetic and the development of treatment demonstrated complete resolution could be due to a a knowledge and skills base in order to use electrosurgery should variety of factors ranging from treatment being provided by a dif- be no barrier to using the technique in cases where it is deemed ferent practitioner using different techniques and, for example, appropriate for recalcitrant lesions [4]. changes in lifestyle and working patterns of the individual. These It was found that some patients referred to the study refused were not investigated. consent to participate because of the (50%) possibility of continuing The classification of each lesion was determined at the time of with standard treatment. Such patients were treated with electro- treatment and the frequency and level of resolution by lesion type surgery immediately. All subjects included in the control group is given in Table 4. The best outcomes in the study would appear to were given the opportunity to have electrosurgery treatment on have been achieved (in the electrosurgery group) with neurovas- completion of the study. cular corns with 3 from 8 (38%) being totally resolved with the remaining 5 (62%) partially resolved with no lesions unresolved. For hard corns comparable data are 18% and 64% with 2 (18%) lesions 5. Conclusions unresolved and for fibrous lesions 33%, 42% and 3 (25%), respec- tively. For the electrosurgery group, Table 5 shows the distribution As the group sample sizes in this study were small, the results and frequency of the three levels of resolution at each of the loca- should be interpreted in that context and larger clinical trials tions where lesions were found. It can be seen that lesions occurred would be useful in verifying these results. However, the outcomes most frequently under the third metatarsal head area where total of the study are broadly in line with those of previous research and partial resolution rates were both 40% but 20% remained unre- and suggest that the use of electrosurgical techniques can pro- solved. At the 4th metatarsal head area, heel and 2nd metatarsal vide an improved treatment modality for long-standing and painful complete and partial resolution rates together were 100%, 80% and hard, fibrous and neurovascular corns which have not responded 75%, respectively. All five lesions at the 5th metatarsal area and the to other forms of treatment. The efficacy of electrosurgery relies one lesion occurring under the hallux showed partial resolution. on its ability to facilitate the removal a greater depth and volume However, the small size of the study renders such analysis of little of helomatous tissue without pain. Although beyond the scope value in forming conclusions from these data. of this study, it is likely that correctly prescribed, fabricated and It should be borne in mind that there can be risks in the use of fitted orthoses which modify foot function and/or plantar force electrosurgery and the cause of the lesion should be determined. distribution would augment this form of treatment and improve The technique may not be appropriate and if an underlying bony longer-term outcomes. Further research and investigation is nec- or soft tissue abnormality is suspected, this should be addressed by essary in order to better understand the effects, benefits and risks of referral to the patient’s GP for suitable investigations and onward electrosurgery and indeed the qualities and effectiveness of func- referral or further assessment by a podiatric or orthopaedic sur- tion and force modifying orthoses. geon. There is the possibility of inadvertent tissue damage and the resultant ulceration from the procedure always requires appropri- Conflict of interest statement ate follow-up and treatment. The potential for scar formation exists, but as in a case referred to this study, tissue damage had already It has been determined that in undertaking this study there occurred with scarring from previous surgical attempts to remove have been no conflicts of interest for any author, contributor or a corn. There have been no reports of a patient’s condition wors- participant. ening after electrosurgical treatment in the small number of cases where there was no improvement in the condition. Patients should be made aware that a degree of post-operative discomfort is normal Acknowledgments for a period of time as healing progresses. A further consideration in the use of electrosurgery is that the The authors would like to thank the following people for their heating of tissues to high temperatures can cause smoke/steam assistance and participation. J.S. Bevans, G. Bosson / The Foot 20 (2010) 12–17 17

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