Clinical evaluation of irradiated, freeze-dried dura mater allograft as a collagen-based barrier in periodontal osseous defects.

The objective of this study was to clinically evaluate freeze-dried dura mater allograft (FDDMA) provided by the Tata Memorial Hospital Tissue Bank, in various periodontal osseous defects and to observe any unwanted healing pattern or adverse reaction.Eleven systemically healthy patients with one infrabony/furcation defect and at least 6 mm or more loss of attachment at selected sites, were scheduled for surgery. At base-line, patients had a good maintenance regime, minimal gingival inflammation and mobility not more than 1 mm in the buccolingual plane (grade 2). The measurements taken were probing pocket depth, clinical attachment level, intrasurgical level of bone and radiographic level of bone. Instead of surgical re-entry, transgingival probing was performed after 12 months of surgery. After debridement the defects were filled with demineralised freeze-dried bone allograft and covered with FDDMA barrier. The results after 12 months were satisfactory (mean gain of attachment 4.33 mm and mean defect fill 3.91 mm). No adverse reaction, infection or delayed wound healing was noted throughout the study.

Reconstructing tumour defects: lyophilised, irradiated bone allografts.

Tumour excision leaves behind large defects. Allografts provide an excellent alternative to autografts without donor site morbidity and are especially useful in large defects or in children where the quantity of available autograft is limited. In this paper we discuss our experience with indigenously procured and processed lyophilised, irradiated bone allografts. Bone allografts were used in 41 patients. They were used morsellised and used in 32 cases. Of these, 25 cases were available for follow-up. These included 21 patients in whom the allograft was used in contained cavities. Complete incorporation of the graft was seen between 6 and 9 months in all these 21 patients. In 4 patients the allograft was layered onto autograft. In only one of these the allograft incorporated with the host bone. Struts were used in 9 cases (3 cases complete intercalary segmental defect, 3 cases of hemicortical defects, 2 cases of allograft-prosthesis composite around the hip, in 1 case an iliac-crest block was used to stop bleeding from an anterior sacral defect). Of these, 2 full segment struts showed no incorporation. Both these patients were on chemotherapy and radiotherapy. There was no follow-up in sacral defect case. All the other struts incorporated with the host bone within 6-9 months.In 5 cases there was sterile postoperative drainage. All these cases went on to uneventful. Deep infection was observed in 4 patients (10%). In one, the graft was removed, another settled uneventfully with subsequent incorporation of graft, and two have a persisting sinus but good incorporation.To restore part of the strength of the struts it was necessary to hydrate them for 30 min prior to use. Autogenous marrow or autograft was used to provide osteoinductive properties.Conclusion. In selected cases the lyophilised, irradiated bone allografts proved to be very useful in reconstruction of large tumour defects.

The use of Irradiated Allografts in Posterior Spinal Fusion for Healed Tubercular Kyphosis in Children.

Post-tubercular spinal kyphosis in children is not only cosmetically unacceptable but functionally disabling as well, as with the progression of the deformity there is a very significant risk of late onset paraplegia. We present our preliminary results in a prospective study of 12 cases of healed post-tubercular kyphosis in children treated with isolated posterior spinal fusion using irradiated allografts and autogenous cancellous grafts.The study included 12 patients of healed post-tubercular kyphosis documented by clinical, radiological and haematological criteria, with >2 spine at risk signs radiologically. The mean age was 7 years. In situ posterior spinal fusion with irradiated allografts and autogenous cancellous bone graft without any instrumentation was done for all the patients. The total follow-up is 5 years (mean 2.8 years).Eight patients (66%) showed a correction of the kyphosis, 3 patients (25%) were static and only 1 patient showed worsening of the deformity. Eleven patients had sound fusion and 1 patient had good fusion but a pseudoarthrosis at the lower vertebral level.Good posterior fusion was achieved because of the judicious use of morcellised, irradiated cancellous allografts with autogenous cancellous grafts. The proposed mechanism of correction is selective anterior column growth vis-à-vis posterior fused mass leading to gradual self-correction and remodelling.Conclusion. In situ posterior spinal fusion with irradiated allografts is a simple, safe, easily reproducible, less morbid surgical procedure with good results which may alter the long term disability of the patients.

The use of irradiated allografts in reconstruction of tumor defects - the tata memorial hospital experience.

A Tissue Bank is a valuable adjunct to tumour management. In bone tumours, the defects produced by ablative surgery can be reconstructed using banked tissue, thereby obviating the donor site morbidity associated with autografts. Allografts are especially useful in large defects or in children where the quantity of available autograft is limited. The use of bone allografts in India has been limited by the availability of good quality, affordable grafts. In this article we share our experience with the use of indigenously produced allografts in limb salvage, as bone graft expanders and as struts. Lyophilised, irradiated bone allografts were morcellised and used in 32 patients. In 21 of these patients the allograft was used in contained cavities. Complete incorporation of the graft was seen between 6-9 months in all the 25 cases available for follow-up. In 4 patients the allograft was layered onto autograft. The allograft incorporated with the host bone in only one of these patients.Struts were used in 9 cases (3 cases complete intercalary segmental defect, 3 cases of hemicortical defects, 2 cases of allograft-prosthesis composite around the hip, 1 case an iliac-crest block was used to stop bleeding from an anterior sacral defect). Of these, no incorporation of the full segment struts was observed in 2 patients who were on chemotherapy and radiotherapy. The sacral defect case was lost to follow-up. All the other struts incorporated with the host bone within 6-9 months. In 5 cases there was sterile postoperative drainage. Overall infection was observed in 4 patients (10%). In one the graft was removed, another settled uneventfully with subsequent incorporation of graft, and two have a persisting sinus but good incorporation. Since radiation and lyophilisation are known to affect the material properties of bone, the grafts were rehydrated in saline for 30 minutes prior to transplantation. Autogenous marrow or autograft was used to provide osteoinductive properties. In selected cases the lyophilised, irradiated bone allografts proved to be clinically useful in the reconstruction of large tumour defects.

Use of irradiated amnion as a biological dressing in the treatment of radiation induced ulcers.

The management of moist skin desquamation (ulceration) following radiation therapy has been a concern since the inception of this therapy. The treatment of skin reactions focuses on promoting healing, improving patient comfort preventing infection and decreasing trauma to the area. Various dressings like topical preparations, hydrocolloid and gentian violet 1 % dressing have been used for its treatment. We present our experience with the use of amnion as a biological dressing in patients with radiation induced ulceration following pelvic radiation using megavoltage beam. The preliminary experience with treatment in 14 patients proved to be cost effective due to a shorter duration of ulcer healing (median of 7 days), fewer dressing changes (median of 4 dressings) and diminished use of analgesics.

Tissue banking in India: gamma-irradiated allografts.

In India, the procurement of tissues for transplantation is governed by the Transplantation of Human Organs Act, 1994. Although this law exists, it is primarily applied to organ transplantation and rules and regulations that are specific to tissue banking which have yet to be developed. The Tata Memorial Hospital (TMH) Tissue Bank was started in 1988 as part of an International Atomic Energy Agency (IAEA) programme to promote the use of ionising radiation for the sterilisation of biological tissues. It represents the Government of India within this project and was the first facility in the country to use radiation for the sterilisation of allografts. It is registered with the Health Services Maharashtra State and provides freeze-dried, gamma irradiated amnion, dura mater, skin and bone. The tissues are obtained either from cadavers or live donors. To date the TMH Tissue Bank has provided 6328 allografts which have found use as biological dressings and in various reconstructive procedures. The TMH Tissue Bank has helped initiate a Tissue Bank at the Defence Laboratory (DL), Jodhpur. At present these are the only two Banks in the country using radiation for the terminal sterilisation of preserved tissues. The availability of safe, clinically useful and cost effective grafts has stimulated innovative approaches to surgery. There is an increased demand for banked tissues and a heightened interest in the development of tissue banks. Inadequate infrastructure for donor referral programmes and the lack of support for tissue transplant co-ordinators however, continue to limit the availability of donor tissue.