Scientific Articles
Use of ultrasound to assess healing of a mandibular distraction wound☆,☆☆

This study was presented in part at the 30th Annual Meeting and Exhibition of the American Association for Dental Research, Chicago, IL, 2001.
https://doi.org/10.1053/joms.2002.34417Get rights and content

Abstract

Purpose: A standardized, noninvasive technique to assess healing of the mandibular distraction wound is not available. Current methods include clinical examination, plain radiography, and computed tomography. These imaging techniques are expensive and obligate the patient to serial radiation exposure. In addition, anatomic overlap and metal artifacts may obscure the distraction gap. In contrast, ultrasound has been shown to be a noninvasive, efficient, and inexpensive way to evaluate bone healing. The purpose of this study was to test the feasibility of ultrasound to evaluate an experimental mandibular distraction osteogenesis wound. Materials and Methods: Distraction devices were placed via a submandibular incision into 24 minipigs. The protocol consisted of 0-day latency and distraction rates of 1, 2, or 4 mm/d for a 12-mm gap. The wounds were assessed in vivo after 0, 8, 16, and 24 days of neutral fixation. Ex vivo radiographs were used to estimate bone fill using a semiquantitative score. A semiquantitative ultrasound score was assigned, and the beam penetration depth was measured in millimeters. Results: In all groups, clinical stability of the distraction wound increased with the duration of fixation. Plain radiographs, taken during neutral fixation, showed that the desired distraction gap was achieved and maintained. The ultrasound score increased with fixation time, whereas beam penetration depth decreased as expected. Ex vivo radiographs showed increasing bone fill score with time and paralleled the ultrasound score. Conclusions: The results of this feasibility study indicate that ultrasound is potentially useful for the assessment of bone formation in distraction osteogenesis wounds. © 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:1038-1044, 2002

Section snippets

Minipig model

Twenty-four female Yucatan minipigs (Charles River Laboratories, Wilmington, MA) in the mixed dentition stage (age, 6 months; weight, 26 to 30 kg) underwent unilateral placement of a single vector semiburied distraction device (Synthes Maxillofacial, Paoli, PA) at the right mandibular angle.21 The distraction protocol consisted of 0-day latency and distraction rates of 1 (n = 8), 2 (n = 8) or 4 (n = 8) mm/d producing a 12-mm gap. Neutral fixation period was from 0 to 24 days. Details of this

Clinical evaluation

All animals survived the surgical procedure and observation period. At the end of distraction (end DO), all animals had developed an occlusal crossbite with deviation of the jaw toward the nondistracted side. All distraction devices remained stable and none were removed prematurely. There were no postoperative infections or wound dehiscences. In all groups, clinical examination revealed increasing stability of the distraction wound with increasing duration of fixation.

Radiographic evaluation

Measurement of gap size

Discussion

Ultrasound is currently used to assess the DO regenerate in long bones,6, 12, 15, 16, 17, 18, 19 whereas little has been reported on its use for evaluation of mandibular DO.9, 20 Clinical reports of US evaluation of the mandibular DO wound have been difficult to interpret because of the variability of osteotomy location and orientation and variability of distraction vector and shape of the resultant bone gap. Reports have also combined patients with different underlying pathology, such as

Conclusion

The results of this study indicate that ultrasonography and ultrasonometry are potentially useful for assessment of the DO wound. Future studies should be conducted to correlate BPD, bone density, and biomechanical properties of the regenerate.

Acknowledgements

The authors thank Julie Glowacki, PhD, for her advice and ideas in getting this project started and Archie Faubert at Knight Surgical Laboratories (Massachusetts General Hospital, Boston, MA) for his help with the animals.

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    ☆

    This study was supported by AO-ASIF Research Grant 120072264368, by Synthes Maxillofacial (Paoli, PA), by a grant from the Hanson Foundation (Boston, MA), and the Department of Oral and Maxillofacial Surgery Research Fund (Massachusetts General Hospital, Boston, MA).

    ☆☆

    Address correspondence and reprint requests to Dr Kaban: Chief, Oral and Maxillofacial Surgery Service, Massachusetts General Hospital, Fruit Street, Warren Building 1201, Boston, MA 02114; e-mail: [email protected]

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    Copyright © 2002 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.