Craniofacial Distraction Osteogenesis

Abstract

Craniofacial Distraction Osteogenesis Samchukov ML, Cope JB, Characin AM eds., St. Louis, MO: Mosby, 2001. ISBN 0-323-01143-9. 634 pgs. This book provides an overview of the origins and evolution of craniofacial distraction osteogenesis, a discussion of the scientific foundations for the procedure, and comprehensive information to assist the clinician in using the technique. This full-color text contains 12 sections with 69 chapters contributed by 119 authors from 17 countries. The introduction, written by the editors, provides an outstanding primer on distraction osteogenesis. They point out that distraction osteogenesis was developed to minimize problems associated with the correction of skeletal deformities. Correction of many congenital deformities, as well as reconstruction after disease or accident, often requires large skeletal movements to which the surrounding soft tissue cannot adapt. The result is often relapse followed by compromised function and aesthetics. Distraction osteogenesis is a biologic process whereby new bone is formed between the surfaces of bone segments that are gradually separated by incremental traction. Distraction force applied to these bone segments also creates tension in the surrounding soft tissues, initiating a sequence of adaptive changes termed distraction histiogenesis. Under the influence of tensional stress produced by gradual bone distraction, active histiogenesis occurs in gingival tissue, blood vessels, ligaments, cartilage, muscles, and nerves. These adaptive changes in the soft tissues allow larger skeletal movements while minimizing relapse. The introduction also includes 106 additional references for those who want to read in even greater depth. Fortunately for readers of this journal, a portion of this text is devoted to use of distraction osteogenesis for procedures involving treatment with dental implants. These sections are extremely well written and provide an excellent reference for those who want to treat patients using distraction osteogenesis . Section Two, on the biologic basis for this technique, will serve as a baseline for those first learning about distraction osteogenesis, as well as for those who are well versed in the techniques of distraction but who want a review of the scientific basis for this treatment modality. Of particular interest to those placing or restoring dental implants is Chapter 6, titled “Placement of Implants into Distracted Bone” by Dr. Yasuhiro Nasoka. He reports on an experiment in which he placed implants into the distracted alveolar process of dogs. Prior to his work, many investigators allowed the distraction regenerate to mature for as long as one year before placing implants. Dr. Nasoka’s research demonstrated that implants could be placed after three weeks of consolidation. His research into the biology of distraction influenced the clinical practice of implant placement into distracted alveolar bone as discussed in Section Eight of this text. Section Eight, on alveolar distraction, is most relevant for those involved in maxillary and mandibular reconstruction utilizing dental implants. Chapter 43, written by Dr. Martin Chin, elegantly demonstrates how alveolar distraction osteogenesis provides comprehensive rehabilitation, including replacement of the lost bone volume, replacement of lost gingiva, and management of periodontal damage so that lost teeth can be replaced by endosteal implants. This chapter discusses the distraction protocol—treatment planning, surgical technique, and device placement—in an easy to follow manner that will allow readers to incorporate this technique into their practices. Also in Section Eight, Drs. Hiding Lazar and Zöller from the University of Cologne discuss development and utilization of a distraction device that is secured to the lateral surface of the alveolar process. By controlling the orientation of this device, they can orient the distraction island either in a pure vertical or in a vertical lingual orientation depending on the specific restorative needs of the patient. The distraction device developed by Lazar and Zöller is larger than the one used by Dr. Chin and is most useful in the mandibular symphysis, although it can be used for larger segments in the posterior maxilla. Several chapters in Section Eight include discussion of distraction implants. Drs. Gaggl, Schultes, and Kärcher discuss the use of distraction endosseous dental implants first to distract, then to restore the alveolar process. Using the distraction implants, they wait 4 months after completion of distraction and then load the distraction implants. They report 30 successful cases of 32 patients treated. Although this technique requires only one surgery, there is a narrow shaft that must bear the occlusal load (as seen in Figure 45–4 on page 405). I would be interested in additional information on how well the implants hold up under function. In subsequent chapters, Dr. McAllister and Drs. Urbani, Consolo, and Lombardo discuss use of an endosseous alveolar distractor, which is later replaced by a standard endosteal implant. The disadvantages of this technique are the need for two surgical procedures and a longer treatment time, including 4 months for consolidation after distraction and 6 months for implant integration. The major advantage of their techniques is that the final restoration is placed on a conventional implant which, at least theoretically, has less potential for implant fracture compared with the technique described by Gaggl, Schultes, and Kärcher. Craniofacial Distraction Osteogenesis will serve as the major reference text for distraction osteogenesis within the craniofacial area for years to come. It provides the historical, biological, and mechanical foundation for this exciting treatment modality.