It is important that the patient be psychologically stable because he/she has to accept the temporary aesthetic disfigurement due to the expanded balloon. They must be clear about this aspect in advance and be willing to go through the entire process. Good quality well-vascularised tissue at the donor site free of any bacterial infection or contamination is a prerequisite since the balloon causes continuously dynamic expansion forces on the tissues over the period of its use. As a foreign body placed under the skin, the presence of any bacterial contamination predisposes to risks of infection and extrusion of the expander.

Selecting the size, shape and volume: There are various methods advocated to select the right size, shape and volume of the tissue expander to be used in any particular case. This is related to the (1) size of the defect, (2) size and location of the available donor site and (3) expected advancement of a hemispherical domed flap.

A time of 2-3 weeks is given for uneventful good primary healing of the incision suture line. No expansion is done during this period. The body tissue reaction forms a smooth sterile film around the expander balloon in this time. A course of broad spectrum antibiotic coverage is provided for the first few days (5-7 days) as in any clean surgical procedure. Any special circumstances may warrant more prolonged medication at the discretion of the surgeon. Suture removal is at 10-14 days.

Patient is then called back weekly on an out-patient basis for the serial expansion process. This is usually done as an office procedure without any anaesthesia. In the paediatric age group, the pain of the needle prick onto the valve at the time of injection may be obviated by the use of topical local anaesthetic gel (prilox) an hour prior to the scheduled procedure. The specific area dabbed with anaesthetic gel should be covered with a gauze piece or a piece of clean plastic wrap for increased efficacy of action of the topical anaesthetic agent.

The skin and tissues are examined for any signs of inflammation and local tenderness. The healed suture line is examined for strength and presence of any stretching/thinning out. The expander is palpated to assess for any folds. The valve is also palpated to assure easy accessibility and placement well away from the expander.

After meticulous cleaning and prepping of the entire area (expander placement area plus valve placement area and around) as for any sterile/aseptic procedure, the valve area is carefully palpated once again and a No. 24 scalp vein is pierced through the skin perpendicularly into the dome of the injection valve. Using a 10 cc/20 cc luer-lock syringe, gentle aspiration is first done to ensure continuity of the system and smooth return of saline from the expander. Then taking care not to introduce any air into the tubing and the balloon, further expansion of the balloon is done with normal saline. The amount of expansion at any particular session is decided by (1) palpating the expanded dome and assessing if it is still soft and pliable (add some more saline) or tight and tense (end of expansion for that session), (2) assessing the skin for signs of continued blanching on pressure at multiple points and good capillary return on release of the pressure (tissue tolerance) and (3) patient tolerance (pain and discomfort with feeling of too much tightness signals end of expansion for that session).[11] All these factors are balanced and fluid added or withdrawn towards the end of expansion in each session.

The scalp vein needle is removed and the prick point is kept under pressure for a minute until any point bleeding stops. The point is dabbed with antiseptic ointment and may be covered with a sterile gauze piece or a Band-Aid for 24 h.

The appropriate entry of additional expansion done and the total volume achieved at each session is meticulously made in the expansion chart. Remarks must be made promptly about any problems seen or symptoms/local signs encountered at each session both for ready reference and medicolegal purposes. Specific fresh instructions related to use of analgesics to get over the discomfort encountered for 24 h or so due to tightness at the end of each session, use of antibiotics if required for any signs of inflammation/potential infection etc., encountered at that session. The importance of observation of this protocol during the expansion process which typically lasts for 6-12 weeks in order to ensure a smooth and complication free treatment process cannot be over-emphasized. The process of weekly or biweekly expansion continues until clinical impressions and actual measurements show that an adequate amount of skin has been expanded.

Although the manufacturer guidelines caution about limiting the amount of expansion to the capacity of the expander, a good quality expander can definitely be safely over-expanded to double the capacity and more, depending on the requirements of the procedure [Figures [Figures22 and and3].3]. However two factors do affect the actual process in practice – (1) the thinness of the skin envelope as the overexpansion continues and (2) the increased risk of back-pressure leakage through the one-way valve.