Considerations for Mandibular Reconstruction in the Pediatric Patient Following Resection of Malignant Tumors

Genetic determinants of periosteum-mediated craniofacial bone regeneration: a systematic review

BACKGROUND

Periosteum-mediated bone regeneration (PMBR) is a recognized method for mandibular reconstruction. Despite its unpredictable nature and the limited degree to which it is understood, it does not share the concerns of developmental changes to donor and recipient tissues that other treatment options do. The definitive role of the periosteum in bone regeneration in any mammal remains largely unexplored. The purpose of this study was to identify the genetic determinants of PMBR in mammals through a systematic review.

METHODS

Our search methodology was designed in accordance with the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines. We conducted a quality assessment of each publication, and evaluated the differences in gene expression between days 7 and 15.

RESULTS

A total of four studies satisfied the inclusion criteria. The subjects and tissues examined in these studies were Wistar rat calvaria in two studies, mini-pigs in one study, and calves and mice in one study. Three out of the four studies achieved the necessary quality score of ≥ 3. Gene expression analysis showed increased activity of genes responsible for angiogenesis, cytokine activities, and immune-inflammatory responses on day 7. Additionally, genes related to skeletal development and signaling pathways were upregulated on day 15. Conclusions: The results suggest that skeletal morphogenesis is regulated by genes associated with skeletal development, and the gene expression patterns of PMBR may be characterized by specific pathways.

Post-operative Outcomes in Pediatric Patients Following Facial Reconstruction With Fibula Free Flaps

EDUCATIONAL OBJECTIVE

Assess outcomes of pediatric facial reconstruction with fibula free flaps.

OBJECTIVES

Free flap reconstruction of complex maxillofacial defects in pediatric patients is rare. Post-operative complications, donor site morbidity, impact on craniofacial growth, and oro-dental rehabilitation are unknown. Our study assesses the outcomes of pediatric maxillofacial reconstruction with composite fibula free flaps.

STUDY DESIGN

Retrospective chart review.

METHODS

Multi-institutional retrospective chart review from 2000 to 2020 on pediatric patients undergoing maxillomandibular reconstruction with fibula free flaps.

RESULTS

Eighty-seven patients underwent 89 surgeries; 5 maxillary and 84 mandibular defects. Median age: 12 years. Defects were acquired following resection of sarcoma/carcinoma 44% or benign tumors 50%. 73% of cases had immediate free flap reconstruction. Closing osteotomies were reported in 74%; 1 in 40%, 2 in 27%, and more than 2 in 6.7%. Hardware was used in 98% and removed in 25%. 9.2% demonstrated long-term hardware exposure, greater than 3 months following reconstruction. Short-term complications: wound infection 6.7%, flap salvage/failure 2.2%, fistula 1.1%, and compromised craniofacial growth: 23%. Two patients developed trismus. Long-term fibula donor site complications: hypertrophic scarring: 3.4%, dysesthesia: 1.1%, and long-term gait abnormality: 1.1%. Dental rehabilitation was performed in 33%. Post-operative speech outcomes showed 94% with fully intelligible speech.

CONCLUSION

Pediatric maxillary and mandible defects repaired with fibula free flaps demonstrated complication rates comparable to the adult free flap population. Long-term follow-up did not demonstrate adverse outcomes for craniofacial growth. Hardware for flap retention was utilized and remained in place with minimal exposure. Post-operative gait abnormality is rare.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:302-306, 2023.

Pediatric Mandible Reconstruction: Controversies and Considerations

Mandibular reconstruction in pediatric patients has some unique considerations. The method of reconstruction has to factor in the growth potential of the neo-mandible, the native mandible, and the donor site. The condyle is considered the main growth center of the mandible. Current literature indicates that fibula, iliac crest, and scapula osseous flaps do not have the ability to grow. Costochondral grafts exhibit growth because of the costal cartilage component, although the growth is unpredictable. Preservation of the mandibular periosteum can result in spontaneous bone regeneration. Fibula bone harvest in a child mandates close follow-up till skeletal maturity, to monitor for ankle instability and valgus deformity. Dental rehabilitation maintains occlusal relationships, which promotes normal maxillary development. Elective hardware removal should be considered to facilitate future dental implant placement and possible revision procedures. After completion of growth, if occlusion or symmetry is not satisfactory, secondary procedures can be performed, including distraction osteogenesis, orthognathic-type bone sliding operations, and segmental ostectomy.