Een ingroeiende of ingegroeide teennagel is een veel voorkomende aandoening die regelmatig in de eerste en tweede lijn wordt gezien en behandeld. Hoewel er een mate van algemene overeenstemming lijkt te zijn in de globale behandelindicatie en technieken, ontbreekt de onderbouwing hiervoor. In deze module wordt hier vorm aan gegeven en wordt een voorstel voor een stapsgewijze operatieve aanpak aangereikt.

Surgical versus non-surgical treatment of ingrown toenails

Surgical gutter treatment versus other surgical treatment

Surgical procedures alone versus surgical procedures plus destruction of the matrix

Different types of ablation/destruction of the matrix

Surgical interventions with pre-/postoperative treatment versus surgical interventions without pre/postoperative treatment

Description of studies

All studies were comparative studies, with the exception of 1 study in the review, which was a within-patient trial. The study sizes varied from 31 to 424 participants. Most studies compared 2 interventions. Due to the nature of the pathology and interventions, placebo or dummy treatments were not included. The various studies used different primary and secondary outcome measures, and the exact quantifications of the outcomes were not always provided in the publications. For pooling of similar types of interventions, the categories used by Eekhof (2012) were used. Twenty-seven studies reported recurrence as an outcome, 17 studies measured postoperative pain and 13 studies used infection as an outcome measure.

Results

Due to the wide range of interventions described, the results are presented per intervention category/comparison (only those comparisons that are currently of clinical relevance according to the working group), and subsequently per outcome measure. Patient populations overall were similar, with in some studies certain particular groups like teenagers (Kormaz, 2013) or males in military service (Kim, 2015). Generally, no information was provided about which medical professional performed the intervention.

Surgical versus non-surgical interventions

Recurrence (critical)

Comparisons between surgical and non-surgical interventions should be made with caution, since the classification “non-surgical” was not always consistent between studies/countries. Contrary to the clustering by Eekhof (2012), gutter treatment was considered surgical in three studies (Peyvandi, 2011; Ceren, 2013; AlGhamdi, 2014), because the treatment involved anesthesia, asepsis, tissue resection and/or manipulation of the nail matrix with surgical instrumentation. In the only study comparing non-surgical with surgical treatment, i.e. orthonyxia (orthesis) (8/51 recurrences) versus partial matrix excision (4/58 recurrences), the RR of recurrence was 0.89 (95% CI 0.77 to 1.04) in favour of surgical intervention (Kruijff, 2008). No quantitative data was reported for post-treatment pain, adverse events and other outcomes for the comparison between surgical versus non-surgical interventions.

Surgical gutter treatment versus other surgical treatment

Recurrence (critical)

Comparing surgical plastic gutter treatment (i.e. gutter treatment that involved anesthesia, asepsis, tissue resection and/or manipulation of the nail matrix with surgical instrumentation) (n= 166) and other surgical treatments (n=175), the mean relative risk (RR) of recurrence in 4 studies was 1.79 (95% confidence interval (CI) 1.00 to 3.20), favoring other surgical interventions, as presented in figure 1 (Wallace, 1979; Peyvandi, 2011; Ceren, 2013; AlGhamdi, 2014). Notably, there was some variation in the symptom severity of included patients. Peyvandi (2011) included patients aged 12 to 50 with a stage III (“Amplified symptoms, granulation tissue, marked fold hypertrophy”) ingrown toenail of hallux referred to the general surgery ward. In the study of Ceren 2013, the majority of patients had a stage III ingrown toenail (n=33, (57.9%) in the non-surgical group and n=39 (61.9%) in the surgical group). In the study of AlGhamdi (2014) participated patients with stage II and stage III ingrown toenails. Twenty-one of 46 (45.6%) patients previously received some conservative treatment for the ingrown toenail. Twelve of these 21 patients previously underwent partial or complete avulsion. In the study by Wallace (1979) patients aged 11 till 36 had stage II to III ingrown toenails with “pain, swelling, discharge, and obvious granulation tissue present in the nail groove”.

Figure 1 Recurrence after surgical gutter treatment versus other surgical treatment

Z: p-value of pooled effect; df: degrees of freedom; I²: statistical heterogeneity; CI: confidence interval

Pain (critical)

The duration (AlGhamdi, 2014) and severity (Ceren, 2011) of postoperative pain were described, and no statistically significant differences between treatments were found. Unfortunately, no values or SDs were provided.

Adverse events: postoperative infection (important)

One study (Peyvandi, 2011) showed that quantified infection was not statistically significant different between surgical plastic gutter treatment (8%) and other surgical treatment (6%) (n=100, RR 1.33, 95% CI 0.31 to 5.65).

Surgical procedures alone versus surgical procedures plus destruction of the matrix

Recurrence (critical)

Several studies compared a surgical procedure with and without chemical ablation or other destruction of the matrix (figure 2). Five studies compared partial nail avulsion with phenol application (38/299 (12.7%) recurrences) with wedge treatment and surgical matrix excision (64/313 (20%) recurrences). These studies showed a pooled RR of 0.66 (95% CI 0.41 to 1.08) in favor of the intervention with chemical ablation, but this estimate was not statistically significant (Varma, 1983; Morkane, 1984; Issa, 1998; Van der Ham, 1990; Leahy, 1990). There was no difference in recurrence in a study by Anderson 1990, comparing total avulsion plus phenol (6/14) and total avulsion plus matricectomy (10/17), with a RR of 0.73 (95% CI 0.35 to 1.50). Two studies comparing partial nail avulsion with phenol or matricectomy found no statistically significant differences with a RR of 0.74 and a 95% CI from 0.32 to 1.68 (Gerritsma-Bleeker, 2002; Bos, 2006). In the comparison between partial nail avulsion combined with chemical ablation (6%, 31/460) and partial or total avulsion without ablation (40%, 74/185), the RR of recurrence was 0.19 (95% CI 0.09 to 0.40) in favor of an intervention with ablation (Sykes, 1988; Shaath, 2005; Bos, 2006; Khan, 2014). This difference was clinically relevant. The weighted RR of all these interventions combined is 0.45 in favor of surgical treatment plus chemical ablation, with a confidence interval from 0.27 to 0.74. This difference was also clinically relevant.

Figure 2 Recurrence after surgical procedures with chemical or surgical matrix destruction.

Z: p-value of pooled effect; df: degrees of freedom; I²: statistical heterogeneity; CI: confidence interval

Although only two studies (Bos, 2006; Khan, 2004) directly compared the same surgical procedure (partial nail avulsion) with versus without phenol application, by clustering the data (table 1), we found that recurrence after treatments with chemical ablation is lower than after intervention without chemical ablation. No statistically significant differences in recurrence rates between chemical and surgical matrix destruction were found.

Table 1 Summary of the effect of chemical matrix destruction on recurrence

Pain (critical)

There was no statistically significant difference in postoperative pain (figure 3) as assessed by a VAS in the study by Gerritsma-Bleeker (2002), when partial nail avulsion (PNA) and phenol was compared to PNA and matrix excision (MD 0.40, 95% CI -0.41 to 1.21), or in the study by Morkane (1984) when PNA and phenol was compared with wedge excision and matricectomy (MD -3.86, 95% CI -14.22 to 6.50).

Figure 3 Pain score after surgical procedures with chemical or surgical matrix destruction

When phenol was added to the surgical intervention, there was significantly less postoperative analgesic used in the phenol group (van der Ham, 1990: RR 0.36, 95% CI 0.25 to 0.54). However, there was no statistically significant difference in postoperative analgesic use in the 2 groups in the study by Arista from 2006 (RR 1.27, 95% CI 0.69 to 2.37), as presented in figure 4.

Figure 4 Analgesic use after surgical procedures with or without matrix destruction

Patient satisfaction

Patient satisfaction (“yes” or “no”) after total avulsion and phenol treatment or total avulsion and matricectomy was not different with a RR of 0.40 and a 95% CI from 0.02 to 9.12 (Anderson 1990).

Different types of matrix destruction

Recurrence (critical)

No statistically significant differences in recurrence were observed in 4 studies that directly compared different types of matrix destruction, as depicted in figure 5. The number of recurrences were low (range 0 till 8).

Figure 5 Recurrence after different types of matrix destruction

Curet = curettage; EC = electrocauterisation

Pain (critical)

The mean difference in pain score 2 days postoperatively (VAS 0 to 10) was 0.89 (95% CI 0.14 to 1.64) favoring phenol application without curettage (mean VAS 3.06 ± 2.21) over phenol application with curettage (mean VAS 3.95 ± 2.25) (Álvarez-Jiménez, 2011). Although the difference was statistically significant, it was not clinically relevant (difference < 2 points) (Figure 6). The addition of electrofulguration to a surgical intervention did not significantly reduce postoperative pain (“yes” versus “no”; RR 0.81, CI 0.35 to 1.86) in one study (Flores, 2006) (Figure 7).

Figure 6 Postoperative pain score after different types of matrix destruction

Figure 7 Postoperative pain after different types of matrix destruction

Surgical interventions with pre-/postoperative treatment versus surgical interventions without pre/postoperative treatment

Recurrence (critical)

In the study by Bos (2006), antibiotic treatment was combined with various surgical interventions. No statistically significant differences in recurrence rates were found between interventions with or without antibiotic therapy, as presented in figure 8. The RR was not statistically significant lower after:

• PNA and surgical matrix excision (ME) without antibiotic treatment versus antibiotic treatment (38.1% versus 42.1%, RR 0.90, 95% CI 0.47 to 1.75).
• PNA and phenol with antibiotics versus without antibiotics (4% versus 21.2%, RR 0.19, 95% CI 0.02 tot 1.44).

It should be noted that recurrence rates in the study by Bos (2006) were considerably higher than in other studies.

Figure 8 Recurrence with or without postoperative treatment

Adverse events: postoperative infection (important)

The four studies that compared postoperative infection after treatment with and without antibiotic therapy found no statistically significant differences between the groups (figure 9).

Figure 9 Postoperative infection with or without postoperative treatment

Level of evidence of the literature

All trials had numerous methodological flaws and were considered at high risk of bias. Most studies did not describe their randomization methods. Moreover, all trials were at high risk of performance bias. Due to the nature of the intervention and control treatment, neither treatment providers nor participants could be blinded, which does not affect the outcome recurrence, but could introduce bias for the other outcomes like pain. Not many studies compared the same interventions or used the same outcome measures. Most studies did not have a published study protocol and the reporting of critical and important outcome measures was limited. In addition, information such as standard deviations (SDs) was not reported in some of the studies.

Surgical versus non-surgical treatment of ingrown toenails

Starting from a high quality level for RCTs, the level of evidence for the outcome measure ‘recurrence’ was downgraded with 1 level for study limitations (risk of bias) and 2 levels for the low number of patients and events (serious imprecision), resulting in a very low level of evidence. We have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

Different types of surgical procedures

Starting from a high quality level for RCTs, the level of evidence for the outcome measures ‘recurrence’, ‘pain’ and ‘infection’ were downgraded with 1 level for study limitations (risk of bias) and 2 levels for the limited number of included patients and the low number of events (serious imprecision), resulting in a very low level of evidence. We have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

For all other combinations of outcomes and comparisons, the level of evidence was downgraded by 2 levels because of study limitations (risk of bias) and either conflicting results (inconsistency) or the limited number of included patients (imprecision). The level of evidence for these outcome measures was considered low. Our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.

A systematic review of the literature was performed to answer the following question:

What are the effects of treatments for ingrown toenails?

P (patients): patients with ingrown toenails;

I (intervention): surgical or nonsurgical intervention;

C (control): control, i.e. sham or alternative intervention;

O (outcome measure): recurrence, regrowth, pain/discomfort/symptoms, adverse events/complications, patient global assessment/patient satisfaction, (work) participation, healing time.

Relevant outcome measures

The guideline development group considered recurrence (regrowth with pain) and (post-operative) pain as critical outcome measures for decision making, while considering adverse events (including infection), patient global assessment and work/hobby participation as important outcome measures for decision making. Finally, healing time was taken into consideration.

The working group defined the outcome measures as follows:

• Recurrence of the ingrown toenail: regrowth with pain, measured after a minimum period of follow-up of six months.
• Regrowth: including nailspikes and spicules as measured after a minimum period of follow-up of six months.
• Pain intensity as measured by visual analogue scale (VAS, with 0 indicating no pain and 100 indicating extremely intense pain), verbal rating scale (VRS) or numerical rating scale (NRS, 0 = no pain; 10 = severe pain).
• Adverse events: all negative effects related to the treatment.
• Patient global assessment: patient satisfaction as reported by the patient.
• (Work) Participation: participation in school, work, informal care.
• The working group did not define the outcome measure ‘healing time’ but used the definition used in the studies.

The working group defined a decrease (difference) of

• 25% recurrences;
• 20 or more points on a VAS (scale from 0 to 100mm) or 2 points on a NRS (scale from 0 to 10) (Olsen, 2018) as a minimal clinically (patient) important difference.

The working group decided to focus on the following comparisons: Non-surgical versus surgical procedures; different types of surgical procedures; surgical procedures alone versus surgical procedures plus destruction of the matrix; different types of matrix destruction (surgical matrix destruction (synonyms: surgical matrix excision, partial matrix excision, matricectomy, curettage or electrocauterisation) versus chemical matrix destruction (synonyms: chemical ablation, phenol application)); surgical interventions with pre- or postoperative treatment versus surgical interventions without pre- or postoperative treatment.

Search and select (Methods)

In an orienting search a published systematic review was found (Eekhof, 2012). This Cochrane review answered the PICO and the working group decided to contact the first author and ask whether an update of this review was available for the working group. This was the case and in February 2019, the working group added the new RCTs to be included in the upcoming update of the Cochrane review.

The Cochrane review included RCTs for the treatment of ingrown toenails (and for the synonyms ’unguis incarnatus’ and ’onychocryptosis’). Randomised trials comparing postoperative treatment were also included. The studies minimum follow-up period was one month.

Results

The Cochrane review by Eekhof published in 2012 included 24 studies with in total 2.826 participants. Eleven studies with a total of 836 participants were added. Important study characteristics and results of these studies are summarized in the evidence table. The assessment of the risk of bias is summarized in the risk of bias table.