Bone healing in rabbit calvarial critical-sized defects filled with stem cells and growth factors combined with granular or solid scaffolds.

PURPOSE: In pediatric neurosurgery, decompressive craniectomy and correction of congenital cranial anomalies can result in major cranial defects. Corrective cranioplasty for the repair of these critical-sized defects is not only a cosmetic issue. The limited availability of suitable autogenous bone and the morbidity of donor site harvesting have driven the search for new approaches with biodegradable and bioactive materials. This study aimed to assess the healing of rabbit calvarial critical-sized defects filled with osteogenic material, either with bioactive glass scaffolds or tricalcium phosphate granules in various combinations with adipose stem cells or bone marrow stem cells, BMP-2, BMP-7, or VEGF to enhance osteogenesis. METHODS: Eighty-two bicortical full thickness critical-sized calvarial defects were operated. Five defects were left empty as negative control defects. The remaining 77 defects were filled with solid bioactive glass scaffolds or tricalcium phosphate granules seeded with adipose or bone marrow derived stem cells in combination with BMP-2, BMP-7, or VEGF. The defects were allowed to heal for 6 weeks before histologic and micro-CT analyses. RESULTS: Micro-CT examination at the 6-week post-operative time point revealed that defects filled with stem cell-seeded tricalcium phosphate granules resulted in new bone formation of 6.0 %, whereas defects with bioactive glass scaffolds with stem cells showed new bone formation of 0.5 to 1.7 %, depending on the growth factor used. CONCLUSIONS: This study suggests that tricalcium phosphate granules combined with stem cells have osteogenic potential superior to solid bioactive glass scaffolds with stem cells and growth factors.

Healing of rabbit calvarial critical-sized defects using autogenous bone grafts and fibrin glue.

PURPOSE: This study aimed to evaluate ossification of cranial bone defects comparing the healing of a single piece of autogenous calvarial bone representing a bone flap as in cranioplasty compared to particulated bone slurry with and without fibrin glue to represent bone collected during cranioplasty. These defect-filling materials were then compared to empty control cranial defects. METHODS: Ten White New Zealand adult male rabbits had bilateral critical-sized calvarial defects which were left either unfilled as control defects or filled with a single full-thickness piece of autogenous bone, particulated bone, or particulated bone combined with fibrin glue. The defects were left to heal for 6 weeks postoperatively before termination. CT scans of the calvarial specimens were performed. Histomorphometric assessment of hematoxylin-eosin- and Masson trichrome-stained specimens was used to analyze the proportion of new bone and fibrous tissue in the calvarial defects. RESULTS: There was a statistically significant difference in both bone and soft tissue present in all the autogenous bone-grafted defect sites compared to the empty negative control defects. These findings were supported by CT scan findings. While fibrin glue combined with the particulated bone seemed to delay ossification, the healing was more complete compared to empty control non-grafted defects. CONCLUSIONS: Autogenous bone grafts in various forms such as solid bone flaps or particulated bone treated with fibrin glue were associated with bone healing which was superior to the empty control defects.

Experience with craniosynostosis treatment using posterior cranial vault distraction osteogenesis.

BACKGROUND: Craniosynostosis compromises the cranial vault volume, severely impede growth, and may lead to increased intracranial pressure (ICP). Posterior cranial vault (PCV) distraction osteogenesis (DO) offers an excellent treatment opportunity for this condition. This article intends to describe the outcomes of PCV DO. MATERIALS AND METHODS: Nine males and seven female children indicated for PCV DO were included in the study. The single vector distraction devices with quick-disconnect distraction rods, a type of miniaturized hardware, was used in all cases. RESULT: Seven of the 16 patients had a history of one or more prior cranioplasty. All reoperations in this series were performed for the indication of raised ICP including five of the scaphocephaly patients and the syndromic patients. Clinical signs of raised ICP were present in all patients with either measured raised intracranial pressure or those with clinical signs of raised ICP preoperatively. There was substantial decrease in the ICP postoperatively. DISCUSSION: The outcomes of this study were encouraging. Placing the distractor stems as flat as possible against the outer layer of the cranial bone seems to be a very important maneuver. This keeps the distractor stem less proud and less likely to sustain future trauma. Removal of the distractor stems keeps the devices further away from the risk of later traumatic dislodgement. Moreover, miniaturized distractors allow precise control of the rate and the amount of distraction.

Posterior cranial vault distraction osteogenesis in craniosynostosis: estimated increases in intracranial volume.

PURPOSE: To study distraction osteogenesis of the posterior cranial vault in children requiring increased intracranial volume. MATERIALS AND METHODS: Ten patients were treated with cranial distractors. Five children had previously been operated for scaphocephaly and one child for Saether-Chotzen syndrome. Two patients had bilateral coronal suture synostosis with Muenke syndrome and two patients had Apert syndrome. At surgery, the cranial bones were mobilized, the head was widened during surgery, and the segments fixed to each other with distractors. Further expansion at a rate of 1 mm/day was performed over 2-4 weeks. The cranium was distracted posteriorly from 20 to 30 mm. RESULTS: The patients all tolerated surgery and distraction well. In all cases, the parents were able to perform the distraction at home. There were no technical problems with the distraction devices. Two cases had minor cutaneous problems, where the distractor penetrated the skin. These cases responded to gentle local wound care measures. At the time of distractor removal, ossification had occurred sufficiently in one of these two cases. In the other case, the device was removed and replaced with a resorbable plate, without any harmful effect on the result. In all cases, sufficient expansion was achieved without causing more cosmetic deformity. Ossification occurred in all cases. This method seems effective, as the calculated increase in intracranial volume was a mean of 20.2% (range 10.2-28.5%). CONCLUSIONS: This preliminary series shows that cranial bone distraction is a useful method for cranial expansion with low morbidity in children with craniosynostosis.

Management of facial asymmetry.

Asymmetries of the craniofacial region encompass a multitude of diverse and potentially complex abnormalities that may be the result of numerous causes. The expression and degree of asymmetry for a given condition, although a highly variable process, is the ultimate determinant of the nature of its treatment. This article highlights some of the key features and treatment strategies for various common facial asymmetries.

Effective correction of frontal cranial deformities using biodegradable fixation on the inner surface of the cranial bones during infancy.

PURPOSE: Fixation of cranial bones in pediatric craniofacial surgery with biodegradable materials has developed into an accepted method. However, placing the fixation material on the outer surface of the cranial bone at the frontal cranium in infants can result in suboptimal cosmetic outcomes, as the plates and screws can be palpable. The placement of resorbable fixation devices on the inner surface of the skull would allow for less obvious fixation beneath the skin with a potentially superior cosmetic result. The authors report the use of such resorbable fixation devices on the inner or endocranial aspect of the cranium which appears to be novel. MATERIALS AND METHODS: Ten patients with the mean age of 14 months (range 7-35 months) were treated with cranial remodeling using poly(lactide-co-glycolide) (PLGA) biodegradable fixation on the inner surface of the cranial bones. Five patients had trigonocephaly, four plagiocephaly, and one brachycephaly. All patients had 3D computed tomography (CT) and clinical photographs done preoperatively and postoperatively at follow-up. The outcome was judged at follow-up by clinical evaluation, photographs, 3D CT, and interview of the parents. The mean follow-up time was 3.5 years (range 0.5-6 years). RESULTS: The primary recovery was uneventful in all cases. No wound infection occurred, but one patient had a minor skin necrosis which required a single revision operation to correct. The cosmetic outcome was scored as excellent, good, fair, or poor. There was no case with delayed union. Seven out of ten cases were judged as excellent and three as good, none as fair or poor. CONCLUSIONS: The use of resorbable PLGA fixation devices on the inner aspect of the skull appears to provide a satisfactory cosmetic result in this small preliminary group of pediatric patients. Further long-term study of these materials in this specific location in a larger patient group is needed.