Alfred Enderle

Hard fallow deer antler: A living bone till antler casting?

Deer antlers are the only mammalian bone structures which regenerate completely every year. Once developed, antlers are cleaned of the velvet‐like skin. Presently it is believed that due to velvet shedding the blood supply is interrupted in the solidifying antler bone. Histological examinations were made on different parts of fallow deer antlers investigated from the time of velvet shedding till the antler casting. The present study on hard (polished) antlers revealed living bone with regions presenting living osteocytes, active osteoblasts, osteoid seams and even early stages of trabecular microcallus formation, thus indicating to a continuous bone remodeling. A well developed vascular system was found despite the presence of hard antler bone. The pedicle bone exhibits a rich supply of capillaries and vessels connected to the spongy core of the main branch and the compact bone as well. There is evidence that hard fallow deer antlers possess a functioning vascular system that “keeps the antler moist” resulting in a high impact resistance when fights are most frequent. As late as 3 weeks prior to antler casting a large number of living cells were discovered within the antler core. As we have no doubt that parts of the polished fallow deer antler represent a living bone, we have concluded that a sufficient blood supply of the antler core is maintained almost till the time of antler casting by vessels passing through the antler base. Anat Rec 255:69–77, 1999.

Histomorphometry of distraction osteogenesis during experimental tibial lengthening.

Objectives The aim of the current study was to analyze distraction osteogenesis histomorphometrically to investigate the amount of enchondral ossification adjacent to intramembranous ossification. Study Design Species-specific, longitudinal time study. Methods Lengthening of 25% of the right tibia was performed in 24 beagle dogs by callus distraction after osteotomy and application of a ring fixator. Distraction was started at the fifth postoperative day with a distraction rate of 0.5 mm twice a day. Twelve dogs were killed at the end of the distraction phase of 25 days (group A) and the remaining 12 dogs after an additional consolidation period of 25 days (group B). The tibia was removed from the distracted right leg and from the left control side of each animal, and longitudinal sections were cut and stained with Pentachrome. In all tibiae, an area of 0.5 × 2.4 cm within the endosteal bone was evaluated histomorphometrically with a Merz grid, and the results were compared between distraction and control side as well as between the dogs of group A and group B. Results On the distraction side, the typical signs of an increased de novo bone formation with a significant increase of osteoblasts and osteoid in group A, as well as an additional significant increase of bone volume and trabecular thickness in group B, were found. In all distraction cases, islands of cartilage formation, which underwent enchondral ossification, were found, besides membranous ossification. The ratio between membranous and enchondral ossification was found to be five to one. Conclusion Bone formation during distraction osteogenesis results from both membranous and enchondral ossification.

Circumferential fusion of the lumbar and lumbosacral spine using a carbon fiber ALIF cage implant versus autogenous bone graft: a comparative study.

This study reports on 92 patients treated with circumferential lumbar fusions for degenerative conditions. The elected procedure was a circumferential fusion using transpedicular stabilization. Two groups were examined depending on whether they were stabilized anteriorly with autogenous bicortical iliac crest graft (n = 38) or with an ALIF carbon fiber cage implant (n = 54). The patients were evaluated for clinical and radiographic outcome. The minimum follow-up interval was at least 12 months. Fusion rates, postoperative loss of correction, and clinical results, including pain at the bone donor site, neurologic function, satisfaction, depression, and consumption of analgesics, were not significantly different between patients with autogenous bone graft and patients with carbon cage. This study failed to prove major advantages of the carbon cages in the clinical and radiologic outcome.

Die temporäre Zementplombe zur Behandlung gelenknaher osteolytischer Knochenläsionen

ZusammenfassungOperationszielAusgiebigste Exkochleation einer gelenknahen osteolytischen Knochenläsion. Temporäre Auffüllung des Defektes mit Knochenzement zur Erhaltung der Gelenkfunktion und der Knochenstabilität sowie zur Vermeidung eines Rezidivs. In einem zweiten Eingriff Ersatz der Zementplombe durch möglichst autogene Knochentransplantate.IndikationenGelenknahe, osteolytische, gutartige oder semimaligne Knochentumoren, auch solche mit fraglicher Dignität sowie tumorähnliche Läsionen, wie z. B. Riesenzelltumoren, Chondroblastome, solitäre und aneurysmatische Knochenzysten, alle charakterisiert durch hohe Rezidivneigung.KontraindikationenBösartige Knochentumoren. Massiv in die Weichteile expandierte Läsionen.OperationstechnikErste Operation: Fensterung des Knochens und vollständige Kürettage; Exzisionsbiopsie. Auffüllen des Defektes mit Knochenzement. Eventuell Verbundosteosynthese. Zweite Operation: Nach mindestens 1-jähriger Rezidivfreiheit Entfernung der Zementplombe und Ersatz durch ein möglichst autogenes Knochentransplantat. Histologische Untersuchung der perifokalen Weichteilmembran (“second look”). Bei Rezidiv erneute Exkochleation und nochmalige Zementplombe.ErgebnisseBei 27 Patienten (zehn männlich, 17 weiblich, Alter 9–68 Jahre) wurden zwischen 1982 und 1999 29 Zementplomben implantiert (23 Primär-, sechs Rezidivoperationen). Drei der primär Operierten wiesen ein Rezidiv auf. Zwei von ihnen wurden mit dem gleichen Verfahren nochmals operiert und blieben bisher 24 bzw. 102 Monate rezidivfrei. Bei einer Patientin mit einem Riesenzelltumor wurde eine Spezialendoprothese implantiert. Die Beobachtungszeit lag zwischen 1 und 151 Monaten, im Durchschnitt bei 49 Monaten. Gelenkfunktion: 14-mal exzellent, zehnmal gut, einmal schlecht. Komplikationen: zwei Frakturen, eine Fistel, eine Arthrose, eine Achsenfehlstellung.AbstractObjectiveExtensive excochleation of juxta-articular osteolytic lesions. Temporary filling of the defect with bone cement to preserve joint function, to prevent fracture and recurrence. During the second sitting, the bone cement is removed and replaced preferably by autogenous bone grafts.IndicationsJuxta-articular osteolytic lesions which are benign or of low malignancy. Lesions of questionable malignity as well as tumorlike conditions such as giant cell tumors, chondroblastomas, unicameral and aneurysmal bone cysts, which are all characterized by a high tendency of recurrence.ContraindicationsMalignant bone tumors, lesions invading the overlying soft tissues.Severe osteoporosis.Surgical TechniqueStage 1: fenestration of bone, complete curettage or excisional biopsy. Filling of the defect with bone cement. Internal fixation if indicated.Stage 2: after freedom from recurrence of at least 1 year, removal of the bone cement and replacement wit preferably autogenous bone grafts. Removel of the perifocal soft tissue membrane for histologic examination. In the presence of recurrence, the excochleations is repeated as well as the filling with bone cement.ResultsBetween 1982 and 1999, the described technique was performed in 27 patients (ten men, 17 women, age 9–68 years). A total of 29 cement fillings were done, 23 for primary surgery, six for recurrences. The initial surgery was followed by three recurrences, two of which underwent repeat filling and remained free of recurrence for 24 and 102 months, respectively.A special tumor prothesis was used in one woman for recurrence of a giant cell tumor. The duration of follow-up varied between 1 and 151 months (average 49 months). The joint function was excellent 14 times, good ten times, and poor once. The following complications were encountered: two fractures, one draining sinus, one osteoarthritis, and one axial malalignment.