6.4. Clinical implications and recommendations

The results of studies I, II, and III clearly show that it is possible to safely harvest CC’s of autogenous bone from the anterior iliac crest with a hand held power driven trephine, using a minimally invasive surgical technique. The technique is both rapid and simple in application. It is well-tolerated, acceptable to patients and creates less morbidity than open anterior iliac crest harvest based on the outcome measures examined in this study. Use of the trephine resulted in fewer days to first unassisted ambulation, shorter overall length of hospital stay, and significantly less donor site pain than following harvest of CCBG’s.

The cadaver study has shown that the technique is meant to be practiced in a gentle manner, in order to avoid perforation of the medial cortex of the ilium. The trephine cutting core guides itself, almost by its own weight through the soft cancellous bone between the medial and lateral cortices of the ilium. Not pushing too hard on the trephine will lessen the chances of perforation. Additionally respecting the funnel-shaped retractor, which will not allow harvested core lengths of greater than 38 mm will also lessen the chances of perforation. These two maneuvers will increase the safety of the technique.

The minimal morbidity and rare complications using this method have allowed the procurement of these grafts on an outpatient basis. This procedure can be carried out predictably in an outpatient or ambulatory surgery environment. However, the ability to use this technique on an outpatient basis is almost completely dependent on the extent of the reconstructive procedure being performed, as well as the overall health of the patient. The operative field in an obese person is far more difficult to manage surgically. It might be prudent to admit such a patient to hospital. Never-the-less modest graft harvests to treat local defects in the cranio-maxillofacial skeleton such as repair of a cleft alveolus, for sinus floor augmentation procedures, for alveolar augmentation and augmentation rhinoplasty are routinely possible without admission to hospital for most patients. This decreased utilization of institutional facilities represents at the least a financial savings to any health care system.

Coral granules seem to be well tolerated in the cranio-maxillofacial skeleton when introduced into a well-vascularized, aseptic, subperiosteal pocket. Complications seem to be few in number and the result is an improvement over the pre-treatment situation in most cases. All of the problems encountered with CDG were of two types, wounds of a questionable nature and in ectopic placement of the granules. CDG must never be placed into an infected bed or into beds with poor vascularity. To do otherwise almost guarantees loss of the xenograft. The granules must also be placed and retained in a subperiosteal location. The granules can cause an inflammatory reaction when placed into a subcutaneous location.

In the dento-alveolar skeleton the CDG placed into the 48 augmentation sites in alveolar sockets healed well with few significant complications and only one overt infection. In the anterior maxilla, the coral granules restored the dimensions of the alveolar ridges only temporarily. Here the CDG did not provide sufficient bony support for the placement of a dental implant without using a revisional bone graft in the vast majority of cases. In the posterior maxilla and mandible, where tooth-loss was due to the elective removal of ankylosed primary molars, almost all the sites were able to support the successful placement of an osseointegrated dental implant without the use of a bone graft. The published results of others (Ostler & Kokich 1994) and clinical experience suggest that the removal of retained ankylosed primary molars often triggers a pattern of resorption which compromises the suitability of these sites for restoration with dental implants. Based upon these results, the routine augmentation of extraction defects with CDG in an effort to preserve alveolar bone volume, until such time as it is safe to proceed with placement of a dental implant following the cessation of skeletal growth is recommended in the posterior maxilla and mandible but not in the traumatized anterior maxilla. Other treatment alternatives to preserve alveolar bone in the traumatized anterior maxilla, without the use of bone grafts including autotransplantation of teeth, orthodontic space closure and decoronation, could be considered.