$files = Get-ChildItem -Filter *.php
foreach ($file in $files) {
    $content = Get-Content $file.FullName -Raw
    $newContent = [regex]::Replace($content, 'instituts-formation-ambulanciers-france-outre-mer-(?!regions)', 'ambulanciers-france-outre-mer-')
    if ($content -ne $newContent) {
        Set-Content -Path $file.FullName -Value $newContent -NoNewline
        Write-Host "Updated $($file.Name)"
    }
}