Middledorpf RetractorNewMed® Middledorpf Retractor is a versatile surgical instrument designed for effective tissue retraction in cardiothoracic and cardiovascular procedures. Measuring 28cm in overall length, it features a 22.0 mm × 20.0 mm, 30.0mm × 26.0mm and 7.0mm × 14.0mm fenestrated blade..