Demineralized bone matrix polydioxanone composite as a substitute for bone graft: a comparative study in rats.

Demineralized bone matrix (DBM) has been successfully used as a substitute for bone grafting. Autogenous bone grafts (ABG) may cause donor site morbidity and undergo significant resorption. DBM may overcome these problems but is mechanically unstable when originally placed. We explored using a slowly resorbable template, polydioxanone (PDS), in combination with DBM and compared it to ABG in a rat 9 x 9 mm cranial defect model. After both 1 and 3 months, histologically and biochemically well-formed bone was present in ABG/PDS and DBM/PDS-treated defects, but not in control defects (PDS alone). Mechanical push-out tests using a servohydraulic testing frame were conducted. Maximum load before failure of DBM/PDS increased from 65% at 1 month to 100% of that of intact skull at 3 months. In contrast, ABG/PDS was 50% as strong as DBM/PDS and not significantly stronger than PDS alone. ABG/DBM did not significantly increase in strength from 1 to 3 months. We conclude that DBM/PDS is better than ABG/PDS in treating cranial defects in the rat model, and that an absorbable osteoinductive bone substitute with superior mechanical advantage is possible without the disadvantages of ABG.     

An in utero model of craniosynostosis.

To define better the pathophysiology of craniosynostosis, we developed an in utero model in rabbits. Premature fusion of the sutures was achieved by osteoinduction using demineralized bone matrix (DBM). Thirty-six fetuses from 18 time-dated pregnant rabbits underwent coronal strip craniectomies and implantation of DBM at 25 days of gestation (term = 31 days). Seventeen (47%) survived vaginal delivery and 10 (28%) survived for long-term follow-up. Surviving, operated animals demonstrated bony fusion across the coronal sutures presumably due to osteoinduction by the DBM. Coronal computed tomographic scans with sagittal reconstructions revealed that experimental animals had taller and wider skulls than nonoperated control animals. We conclude that employing DBM to create craniosynostosis in the fetal rabbit is technically feasible. Such a model may be used to more clearly define the pathophysiology of craniosynostosis and to evaluate methods of treatment.     

A standardized method of X-ray CT for sagittal splitting osteotomy of the mandibular ramus

A useful standardized method of X-ray computed tomography (CT) was proposed for the preoperative examination of sagittal splitting osteotomy of the mandibular ramus. In our assessment conducted for cases of mandibular prognathism operated on by a modified technique, the most informative CT image of the mandibular ramus was provided by the scans between the upper and lower dentitions in the open mouth position at which the scan-plane angulation was given as parallel to the dentition in each jaw. These sections enabled preoperative assessment on the mesio-lateral thickness of the marrow space and the positional relationship between the ramal cortices and the mandibular canal together with other geography of the ramal bone structure. Using these CT images, the plane of sagittal osteotomy is predictable. A technique for obtaining standardized CT slice is proposed in this report.     

Experimentelle Untersuchungen zum Einfluß der Ovarialhormone auf die Entwicklung der Rattenmandibula

Zusammenfassung Weiblichen Ratten des Wistar-Stammes wurden am 1. oder 2. Lebenstag die Ovarien entfernt. Intakte Wurfgeschwister dienten als Kontrolltiere. An den mazerierten Unterkiefern erfolgten Flächen- sowie Längen- und Streckenmessungen von der Geburt an bis zur Pubertät. Es zeigte sich, daß insgesamt die Wachstumsraten bei den neonatal ovarektomierten Tieren im Vergleich zur Kontrollgruppe geringer waren. Deutliche Unterschiede wurden vor allem an den Mandibularflächen und im Vertikaldurchmesser des Kondylarbereiches gefunden. Der Flächeninhalt der Mandibulae stieg im Untersuchungszeitraum auf das 6fache, die Fläche im Bereich der Kondylen vergrößerte sich im gleichen Zeitraum auf das 14fache. Aus den Ergebnissen kann gefolgert werden, daß das Wachstum der Mandibula durch die niedrige präpubertale Sekretion der Ovarialhormone stimuliert wird. Den stärkeren Einfluß üben aber wahrscheinlich andere Wuchsfaktoren, z. B. Wachstumshormon, Schilddrüsenhormone, Androgene und wahrscheinlich das Insulin aus.

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Summary Female rats of a Wistar strain were ovariectomized on the first day of life. Intact littermates served as controls. The growth of the mandibles was evaluated from birth till puberty by measuring the total area as well as the length and the distance between different points. The results demonstrated a generally lower mandibular growth in the neonatally castrated females as compared to the intact controls. Significant differences were mainly found in the total area of the mandible as well as in the vertical diameter of the condyles. Throughout the period of investigation, the total area of the mandibles increased 6fold and that of the condyles 14fold. The findings suggest that the relatively low oestrogen secretion during the prepubertal development stimulates mandibular growth, but that the predominant influence may be exerted by other growth factors, e. g. growth hormone, thyroid hormones, androgens and probably insulin.

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Résumé Des rates de la colonie Wistar furent ovariectomisées un ou deux jours après la naissance. Des soeurs intactes servirent de contrôle. Depuis la naissance jusqu'à la puberté, on mesura la croissance des mandibules, tant sur leur surface totale que sur leur longueur et on nota la distance séparant différents points donnés. Les résultats ont montré une croissance mandibulaire généralement inférieure chez les femelles châtrées, dans la période néonatale, par rapport aux femelles intactes du groupe de contrôle. On observa des différences significatives dans la surface mandibulaire, ainsi que dans le diamètre vertical de la région condylienne. La surface totale des mandibules augmenta de 6 fois et celle des condyles de 14 fois pendant la période d'observation. On pourrait conclure, au vu des résultats obtenus, que la croissance mandibulaire est stimulée par la sécrétion prépubérale relativement basse d'oestrogènes, mais que l'influence prédominante appartient probablement à d'autres facteurs de croissance, tels que l'hormone de croissance, les hormones thyroidiennes, les androgènes et probablement l'insuline.

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Herrn OMR Prof. Dr. med. habil.R. Fränkel zum 75. Geburtstag, vorgetragen beim Geburtstagssymposium in Reinhardsbrunn.     

The Furlow Z-plasty in two-staged palatal repair modifications and complications

OBJECTIVES: To report the modifications and complications of the Furlow palatoplasty for two-stage closure of the palate. PATIENTS AND METHODS: Prospective study of a consecutive series of 45 primary closures of the soft palate portion of clefts extending into the hard palate; mean (S.D.) age at repair 12 (2) months; median follow-up 4 years 4 months (range 2 months to 9 years). The hard palatal part of the cleft was closed in 18 patients at the mean age of 3 years 11 months. RESULTS: The main modifications that we made were the use of quilting sutures, lateral V-Y closures, and fibrin glue application, and the omission of lateral releasing incisions. Patients stayed in hospital for a median of 4 days (range 3-8 days). Two patients had postoperative partial obstruction of the airway and were given steroids. In six patients, a smaller portion of the oral layer of the wound broke down; it healed by secondary intention in five, but resulted in partial dehiscence in one. There were no oronasal fistulas in the 18 patients who had delayed closure of the hard palate part of the cleft. Secondary pharyngoplasty was not necessary in any patient. CONCLUSION: Furlow's technique has been modified for use in the two-stage closure of complete cleft palates (with or without cleft lip or alveolus) with an acceptable rate of complications.     

Assay of bone morphogenetic protein-2, -4, and -7 in human demineralized bone matrix

Demineralized bone matrix (DBM) is a widely used bone graft material that derives its osteoinductive potential from matrix-associated bone morphogenetic proteins (BMPs). Prior investigations have shown that the osteoinductive potential can vary widely, with influence from both donor and processing sources. Although it is plausible that donor variance in the BMP profile can be an important consideration, the few published studies available have given inconsistent and incomplete information about this. The goal was to (1) characterize the variance of BMP-2, BMP-4, and BMP-7 in fully demineralized DBM derived from 20 appropriately screened (Food and Drug Administration and the American Association of Tissue Banks criteria) donors (male and female, 17-65 years) and (2) using literature review, infer the potential for this to be an important source of variability in graft function. BMPs were extracted with 4 M guanidine hydrochloride, and levels of BMP-2, BMP-4, and BMP-7 were measured using enzyme-linked immunosorbent assay. Measured levels were as follows: BMP-2 = 21.4 +/- 12.0 ng/g DBM, BMP-4 = 5.45 +/- 2.04 ng/g DBM, and BMP-7 = 84.1 +/- 34.4 ng/g DBM, which were significantly different (P < 0.05). There was a positive linear correlation between BMP-2 and BMP-7 (P = 0.0227). DBM derived from female donors had significantly greater concentrations of BMP-2 and BMP-7 than did that derived from male donors (P = 0.0257 and 0.0245, respectively). There was no significant correlation between donor age and the levels of any of the measured BMPs. The magnitude of variance of BMP profile appears to reasonably well correspond to the variance in osteoinductive potential cited by others, suggesting the possibility of using this as a method of donor screening.     

Patient evaluation of outcomes of external rhinoplasty for unilateral cleft lip and palate

Thirty-five patients (range 16-59 years) with cleft-lip nasal deformity treated by external rhinoplasty were evaluated for satisfaction and perception of outcomes. Treatment involved alar base relocation and augmentation of the asymmetric nasal tip with auricular cartilage grafts. The patients completed a satisfaction survey and interview at the 2-year follow-up visit. A visual analogue scale (VAS) numbered 0-10 was also used by the patients to grade outcome compared to preoperative appearance at 4 anatomic sites. Prior to surgery, the nasal tip was perceived as being most deformed (15/35), followed by alar position (12/35) and nasal apertures (8/35). The site on the nose most improved by surgery was the tip (15), followed by alar position (10), symmetry of nostrils (6) and dorsum (4). The highest VAS score was for the tip (8.32), followed by alar position (7.59), dorsum (7.41) and symmetry of nostrils (6.73). No patients suffered long-term pain for more than 2 months following surgery. All patients were prepared to undergo such procedure for a second time, if necessary. The unilateral cleft-lip nasal deformity can be improved in the eyes of the patient, using the combination of external rhinoplasty with alar base relocation, where necessary, and auricular cartilage augmentation of the nasal tip.     

Evaluation of alveolar bone grafting: a survey of ACPA teams.

OBJECTIVE: To evaluate the management of alveolar clefts by cleft palate and craniofacial teams in North America. DESIGN: An anonymous survey was mailed to 240 American Cleft Palate- Craniofacial Association teams across North America regarding alveolar bone grafting. The questionnaire included multiple questions about each team's approach to alveolar bone grafting and options for the missing tooth. RESULTS: Consensus was achieved in three areas: 90% of centers performed secondary alveolar bone grafting, 78% performed grafting between ages 6 and 9 years, and iliac crest donor site was the most popular site (83%). There was no consensus with respect to dental criteria for the timing of grafting, follow-up x-rays, or the use of a grading system for evaluating results. In addition, there was no consensus on the management of the missing tooth. CONCLUSION: There is wide acceptance of secondary bone grafting and there is a consensus for the age of grafting (6 to 9 years) and donor site (iliac crest). The disturbing finding was the lack of postoperative x-ray evaluation of the results. With so much variability in management, the use of a routine, standardized scale to measure postoperative results would allow for better outcome studies in alveolar bone grafting.