ZSI 475 FTM inflatable penile implant.

01 Overview

Rigidity and concealment through a hydraulic operating principle.

ZSI 475 FTM, designed specifically by the Switzerland-based Zephyr Surgical Implants for patients whose neophallus reconstruction by phalloplasty is complete, is an inflatable penile implant. Unlike conventional penile implants, it is configured for a neophallus anatomy without corpus cavernosum: the single cylinder is placed inside the neophallus, the saline-filled reservoir in the pelvis and the manual pump in the neoscrotum.

The system remains entirely inside the body and is not visible externally. By squeezing the pump in the neoscrotum, the patient transfers fluid from the reservoir to the cylinder; once the desired rigidity is reached, the cylinder maintains the firmness required for penetration. Pressing the valve on top of the pump returns the fluid to the reservoir and the neophallus regains its natural flaccid appearance. This inflatable/deflatable behaviour constitutes the decisive difference from malleable implants in terms of concealment and cosmetic outcome.

Lisa Health provides hospitals and reconstructive urology teams with documented supply of the ZSI penile implant portfolio, sizing planning support and operating theatre preparation documentation. The clinical decision and determination of indication rest solely with the specialist physician.

02 Clinical indications

In which cases is it considered?

The ZSI 475 FTM is positioned for reconstructive cases in which rigidity has to be provided in the neophallus. The headings below summarise the clinical contexts most often considered; the final indication, timing and patient suitability are determined solely by the reconstructive urology team.

• After gender-affirming surgery: in cases where phalloplasty has been completed with techniques such as the radial forearm free flap (RFFF), ALT or MLD, penile implant placement is planned as the final reconstructive step once tissue healing and sensory reinnervation have been achieved.
• Penile reconstruction after trauma: mechanical provision of erectile function in patients reconstructed with a flap after total or subtotal penile loss.
• After oncological penectomy: selected cases reconstructed with phalloplasty following penile cancer surgery.
• Congenital anomalies: after flap reconstruction in cases of aphallia or severely deficient penile development.
• Cases in which the inflatable option is preferred: where concealment, a flaccid cosmetic appearance and avoiding continuous pressure on the neourethra are prioritised, a hydraulic system is considered instead of a malleable implant.

Contraindications, active infection, insufficient tissue perfusion and assessment of patient compliance are addressed within the framework of the current instructions for use and clinical protocols.

03 Structure and components

A three-component, pre-connected hydraulic system.

The device comes out of the box pre-connected and pre-filled with saline. This approach aims to eliminate connection steps in the operating theatre and thereby reduce the risk of connection error and the manipulation time.

• Cylinder (inside the neophallus): a single cylinder designed to preserve stability and cosmetic outcome both inflated and deflated. The ventral passage in the glans section reduces pressure on the neourethra.
• Proximal fixation plate: the plate, made from a combination of stainless steel and silicone, allows the implant to be securely fixed to the pubic bone; in a neophallus without corpus cavernosum support this is a critical design element for preventing migration.
• Reservoir (pelvic): a saline store; it is placed in the pelvic region.
• Manual pump (neoscrotal): single-handed operation, squeezing to inflate and using the valve on the upper part to deflate.
• Material: all wetted surfaces are manufactured from medical-grade silicone elastomer.
• Surface coating: PVP + antibiotic coating is applied to contribute to protection against infection, according to the manufacturer's documentation.
• Set contents: all components and accessories are delivered in a single box, ready for implantation.

04 Size chart

Intraoperative flexibility with four cylinder lengths.

The cylinder length is chosen according to the neophallus dimensions obtained with phalloplasty. The four-step length range is intended to cover the anatomical variation resulting from different flap techniques.

The dimensions are compiled from the manufacturer's catalogue; final values are confirmed with the official product documentation shared with the institution and the current instructions for use.

05 Operating principle

Hydraulic use in four steps.

The system works as a closed hydraulic circuit; fluid is transferred between the reservoir and the cylinder via the pump. Operation is single-handed and requires no external component.

• 1 — Flaccid position: the cylinder is empty and the neophallus retains its natural flaccid appearance.
• 2 — Inflation: the pump in the neoscrotum is squeezed and released repeatedly to transfer fluid from the reservoir to the cylinder.
• 3 — Rigidity: the desired firmness is achieved; the cylinder resists pressure of over 500 g.
• 4 — Deflation: holding down the valve on the upper part of the pump returns the fluid to the reservoir and the neophallus moves into the flaccid position.

06 Distinguishing advantages

Highlights for the operating theatre and the patient's quality of life.

• Reduced risk of connection error: the pre-connected and pre-filled set eliminates intraoperative assembly steps.
• Design addressing infection risk: the PVP + antibiotic coating and reduced manipulation are positioned by the manufacturer as contributing to a lower infection risk.
• Bone fixation: secure anchorage without corpus cavernosum support thanks to the proximal plate.
• Neourethral protection: the ventral passage design in the glans reduces pressure on the neourethra.
• Cosmesis and concealment: a fully flaccid appearance when deflated; it is not conspicuous under clothing.
• Imaging and travel compatibility: designed for safe use in medical scanners; not detected by airport security scanners.
• Warranty: the manufacturer defines a warranty period of 1 year.

07 Comparison

Choosing between the ZSI 475 FTM and the ZSI 100 FTM.

The decisive criteria in choosing a penile implant after phalloplasty are patient expectation, manual dexterity, tissue quality and cosmetic priorities. The table below compares the two ZSI options for institutional assessment; the clinical preference rests with the specialist physician.

08 Technical summary

Institutional evaluation table.

09 Questions & answers

Frequently asked institutional questions.