Dimensional stability of the free fascia grafts: an animal experiment.

OBJECTIVES/HYPOTHESIS: It appears that autologous free fascia grafts (fascia lata and temporal fascia) change their dimensions during the vital first 5 days of healing. Poor dimensional stability of these grafts can be an important reason for failure of complete closure of tympanic membrane perforations in tympanoplasty operations. There has been no study regarding this dimensional instability.

STUDY DESIGN: Prospectively dimensional instability of the free fascia grafts studied in 14 mongrel dogs.

METHODS: Fourteen healthy Mongrel dogs were operated on twice. During the first surgery, fascia lata and temporal fascia grafts of measured dimensions (length, breadth, and thickness) were implanted in the subcutaneous pockets on the thoraco-abdominal wall of the same dog (autograft). Five dogs were operated on again after 2 days, and 7 dogs were operated on again after 5 days to harvest the implanted grafts. The dimensions of the harvested grafts were noted. Changes with respect to their implant dimensions after 2 days and after 5 days were calculated.

RESULTS: It was found that free fascia lata exhibits significantly superior dimensional stability when compared with free temporal fascia during the early healing phase, before graft integration has occurred. Shrinking and thickening of temporal fascia are greater and are also most unpredictable.

CONCLUSIONS: Poor dimensional stability of temporal fascia may compromise a well-sealed perforation at the time of surgery, and it may reopen by the 5th day. This must be one of the causes of failure of tympanoplasty, which needs to be studied further.