Biomechanical Assessment of Regenerate Integrity in Irradiated Mandibular Distraction Osteogenesis

Schwarz, Daniel; Jamali, Ameen M.; Kakwan, Mehreen S.; Fregene, Alero; Arman, Krikor G.; Buchman, Steven R.

doi:10.1097/prs.0b013e318191c5d2

Cited by 21 publications

(21 citation statements)

References 38 publications

(35 reference statements)

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“…[13, 14, 21-23] In Part I and Part II of this series our laboratory was able to demonstrate a dose dependent depletion of both osteogenic cells as well as biomechanical properties secondary to XRT. [13, 14] The purpose of this study was to determine a dose that would correlate with human cancer treatment and to investigate doses both above and below the target dose in order to identify measurable differences between radiated and non-radiated bone utilizing microCT analysis.…”

Section: Discussionmentioning

confidence: 99%

Dose-Response Effect of Human Equivalent Radiation in the Mandible

Monson

Jing

Donneys³

et al. 2013

Journal of Craniofacial Surgery

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Background Despite widespread use of adjuvant irradiation for head and neck cancer, the extent of damage to the underlying bone is not fully understood, but is associated with pathologic fractures, nonunion, and osteoradionecrosis. The authors’ laboratory previously demonstrated that radiation significantly impedes new bone formation in the murine mandible. We hypothesize that the detrimental effects of human equivalent radiation on the murine mandible results in a dose-dependent degradation in traditional micro-CT metrics. Methods Fifteen male Sprague-Dawley rats were randomized into three radiation dosage groups: low (5.91 Gy), middle (7 Gy), and high (8.89 Gy), delivered in five daily fractions. These dosages approximated 75, 100 and 150 percent, respectively, of the biologically equivalent dose that the human mandible receives during radiation treatment. Hemimandibles were harvested 56 days after radiation and scanned using microCT. Bone mineral density, tissue mineral density, and bone volume fraction were measured along with microdensitometry measurements. Results Animals demonstrated dose dependent side effects of mucositis, alopecia, weight loss and mandibular atrophy with increasing radiation. Traditional microCT parameters were not sensitive enough to demonstrate statistically significant differences between the radiated groups; however microdensitometry analysis showed clear differences between radiated groups and statistically significant changes between radiated and non-radiated groups. Conclusions The authors report dose-dependent and clinically significant side effects of fractionated human equivalent radiation to the murine mandible. The authors further report the limited capacity of traditional micro-CT metrics to adequately capture key changes in bone composition and present microdensitometric histogram analysis in order to demonstrate significant radiation induced changes in mineralization patterns.

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Section: Discussionmentioning

confidence: 99%

Dose-Response Effect of Human Equivalent Radiation in the Mandible

Monson

Jing

Donneys³

et al. 2013

Journal of Craniofacial Surgery

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“…Having performed this mandibular distraction osteogenesis and partially reduced fracture procedure over the years, 26–29,33–36 we briefly describe it as follows. Under sterile conditions, using general anesthesia, a midline incision was placed from the submentum to the neck crease, elevating skin flaps exposing the anterolateral mandible.…”

Section: Methodsmentioning

confidence: 99%

“…4,23–25 We used conventional destructive metrics, and established meticulous quantitative histomorphometric protocols, which could be correlated with our biomechanical outcome studies 26 and ultimately nondestructive imaging metrics for future studies. Our specific aim was to quantitatively measure the tissue and cellular constituents of an established region of interest, referred to as tissue volume, within the regenerate after unilateral mandibular distraction osteogenesis in comparison with the contralateral mandibles.…”

mentioning

confidence: 99%

Regenerate Healing Outcomes in Unilateral Mandibular Distraction Osteogenesis Using Quantitative Histomorphometry

Schwarz

Arman

Kakwan

et al. 2010

Plastic and Reconstructive Surgery

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Background The authors’ goal was to ascertain regenerate bone-healing metrics using quantitative histomorphometry at a single consolidation period. Methods Rats underwent either mandibular distraction osteogenesis (n=7) or partially reduced fractures (n=7); their contralateral mandibles were used as controls (n=11). External fixators were secured and unilateral osteotomies performed, followed by either mandibular distraction osteogenesis (4 days’ latency, then 0.3 mm every 12 hours for 8 days; 5.1 mm) or partially reduced fractures (fixed immediately postoperatively; 2.1 mm); both groups underwent 4 weeks of consolidation. After tissue processing, bone volume/tissue volume ratio, osteoid volume/tissue volume ratio, and osteocyte count per high-power field were analyzed by means of quantitative histomorphometry. Results Contralateral mandibles had statistically greater bone volume/tissue volume ratio and osteocyte count per high-power field compared with both mandibular distraction osteogenesis and partially reduced fractures by almost 50 percent, whereas osteoid volume/tissue volume ratio was statistically greater in both mandibular distraction osteogenesis specimens and partially reduced fractures compared with contralateral mandibles. No statistical difference in bone volume/tissue volume ratio, osteoid volume/tissue volume ratio, or osteocyte count per high-power field was found between mandibular distraction osteogenesis specimens and partially reduced fractures. Conclusions The authors’ findings demonstrate significantly decreased bone quantity and maturity in mandibular distraction osteogenesis specimens and partially reduced fractures compared with contralateral mandibles using the clinically analogous protocols. If these results are extrapolated clinically, treatment strategies may require modification to ensure reliable, predictable, and improved outcomes.

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“…32 The regenerated bone obtained by distraction seems to show inferior mechanical properties than the native one, thus not always allowing implants to be placed. 31 Finally, the exteriorisation of the distraction device appears from our point of view to be a gateway for infection, which goes against the precautionary principle we must follow with these irradiated patients.…”

Section: Bone Distractionmentioning

confidence: 98%

“…31 It is likely that beyond a threshold dose of irradiation, distraction osteogenesis is not possible, this dose not being defined yet. 32 The regenerated bone obtained by distraction seems to show inferior mechanical properties than the native one, thus not always allowing implants to be placed.…”

Section: Bone Distractionmentioning

confidence: 99%