Review article
Meta-analysis of complication rates of the tubularized incised plate (TIP) repair

https://doi.org/10.1016/j.jpurol.2014.12.006Get rights and content

Summary

Objective

To determine overall complication rates of the tubularized incised plate (TIP) repair and assess the effects of technical modifications, length of follow-up and geographical location of reported results.

Materials and methods

A systematic literature search was undertaken, using Medline and Pubmed, in order to identify relevant articles. Random effects models were used to estimate pooled complication rates. Meta-regression was performed for each outcome by using mixed effects models with type of hypospadias (primary distal, primary proximal and secondary) as predictors.

Results

Of the 189 articles that were identified, 49 studies (4675 patients) were included in the analysis. Fistula and re-operation rates were significantly higher in secondary repairs (15.5% and 23.3%) compared to primary proximal (10.3% and 12.2%) and primary distal (5.7% and 4.5%) (P = 0.045 and P < 0.001, respectively). Technical modifications reduced fistula rates from 10.3% to 3.3% (P = 0.003) and re-operation rates from 13.6% to 2.8% (P = 0.001). The rate of meatal stenosis was highest in the secondary repairs, with follow-up >1 year (12.7%). Comparison of geographical location showed that complication rates for all but one variable were significantly lower in North America when compared to Europe and the rest of the world. Mean meatal stenosis rates were 1.8% in North America, 3.4% in Europe and 8.2% in the rest of the world (P = 0.002). This remained significant in a multivariable model incorporating repair technique and length of follow-up (P = 0.046). Mean rates of urethral stricture, fistula and re-operation followed a similar pattern (P = 0.045, P = 0.009 and P < 0.001, respectively). Mean follow-up was shortest in the North American group, at 11.9 months, compared to Europe, at 17.8 months, and the rest of the world, at 18.9 months.

Table. Mean follow-up duration and percentage incidence of complications, and total number of patients assessed from the studies reviewed for each degree of hypospadias.

Empty CellPrimary distal hypospadiasPrimary proximal hypospadiasSecondary hypospadias
Number of patients3621625429
Mean follow-up (months)16.116.022.8
Mean % incidence of meatal stenoses3.64.48.3
Mean % incidence of fistulae5.710.315.5
Mean % incidence of urethral strictures1.32.03.0
Mean % incidence of re-operations4.512.223.3

Discussion

The present meta-analysis has shown that the lowest complication rates for the TIP repair are when it is applied to primary distal hypospadias. Complication rates are higher for all variables when the TIP repair is used for primary proximal hypospadias. Lower complication rates than those reported in this TIP review have been documented in some studies using a staged repair for correction of primary proximal or secondary hypospadias [11,12,68], implying that a staged approach may be superior to the TIP repair in these settings.

Documentation of follow-up duration was limited, making assessment of the impact of length of follow-up difficult. Geographical location had a noticeable effect on outcome, with all but one complication being lower in the North American than the other groups. Mean follow-up was shortest in North America and it is suggested that the short follow-up in the North American studies may have led to under-reporting of late complications.

Conclusion

The TIP repair has evolved to incorporate modifications that have significantly lowered complications. Higher complication rates are seen with secondary and proximal repairs; however, limited, published long-term data impair a true assessment of outcome.

Introduction

Over 300 methods of surgical repair have been described for the correction of hypospadias, with no one procedure accepted as the gold standard for each degree of hypospadias. First described in 1994 by Snodgrass [1], the tubularized incised plate (TIP) urethroplasty has become the most popular technique for distal hypospadias [2], [3]. Originally described for correction of distal hypospadias, it has also been applied to more severe proximal forms.

There is a wide discrepancy between published complication rates for different repair types [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16] and a poor evidence base for the current management of hypospadias. Due to the popularity of the TIP repair technique, a large number of papers giving outcomes and complication rates have been published. As there is a paucity of randomised, controlled trials, a meta-analysis of the outcomes of the TIP repair was performed with a view to:

  • 1.

    Assessing the appropriateness of its application to all degrees of hypospadias.

  • 2.

    Evaluating the long-term results by analysing the pooled complication rates to accurately determine representative complication rates for this technique.

  • 3.

    Reviewing the effects of technical modifications, length of follow-up and geographical location of these complications.

Section snippets

Data collection

Medline and Pubmed were searched in order to identify articles published between 1994 and 2012. The search terms ‘tubularized incised plate urethroplasty/Snodgrass repair/technique ± outcomes/complications ± follow-up/long term follow-up’ were used. The following data were extracted independently from each article by two reviewers (K.P and P.C): study size; degree of hypospadias (classified by meatal location: distal – midshaft distally, proximal – proximal shaft proximally); primary or

Overall complication rates

Fistula rates were significantly higher in secondary repairs (mean 15.5%, range 12.1–19.6%) compared to primary proximal (mean 10.3%, range 6.3–16.3%) and primary distal (mean 5.7%, range 4.0–8.2%) (P = 0.005). Re-operation rates were significantly higher in the secondary repairs (mean 23.3%, range 18.5–28.9%) compared to primary proximal (mean 12.2%, range 7.7–18.6%) and primary distal repairs (mean 4.5%, range 2.7–7.5%) (P < 0.001). Meatal stenosis rates were higher in secondary repairs (mean

Discussion

This meta-analysis shows the lowest complication rates for the TIP repair when it is applied to primary distal hypospadias, with mean rates of meatal stenosis at 3.6% (range 1.7–7.4%), urethral stricture at 1.3% (range 0.8–2.2%), fistula at 5.7% (range 4.0–8.2%) and re-operation at 4.5% (range 2.7–7.5%). The fistula rate is higher than the re-operation rate as one paper reports spontaneous healing of three fistulae [24]. Several studies, including the review paper by Wilkinson et al. [66]

Conclusions

Experience so far with the TIP repair has shown that modifications have reduced the complications. The wide reporting of modifications suggests that surgeons have found that the initial technique was in need of changing. Lack of standardised outcome measure reporting has significantly reduced the available papers for the present study, which limited the power of the analysis. It is suggested that outcome measures become established as criteria for acceptance for publication. The minimum

Ethics approval

Ethics approval was not required.

Conflict of interest/Funding statement

None of the authors have any conflicts of interest or funding to declare.

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