Three-dimensional alloplastic orbital reconstruction in skull base surgery

Advancements in facial implantology: a review of hydroxyapatite applications and outcomes

Background

The search for an ideal bone substitute in reconstructive surgery has led to the exploration of various materials, with hydroxyapatite (HaP) emerging as a promising candidate due to its biocompatibility, osteoconductive properties, and structural similarity to human bone. Despite its potential, there is a paucity of data on the long-term safety and efficacy of HaP in facial skeletal reconstruction and augmentation.

Methods

We conducted a systematic review following PRISMA 2020 guidelines, searching PubMed/MEDLINE, Google Scholar, CENTRAL, and Web of Science databases for studies on hydroxyapatite facial implants in reconstruction and augmentation.

Results

Our search yielded 12 studies that met our inclusion criteria, encompassing 74 patients treated with HaP implants for various indications including facial fractures/defects, aesthetic facial balancing, and after tumor resection. The studies reported on outcomes such as implant integration, complications, aesthetic results, and patient satisfaction, with a general trend indicating positive outcomes for the use of HaP in facial reconstruction.

Conclusion

Hydroxyapatite appears to be a viable and effective material for facial skeletal reconstruction and augmentation, offering benefits in terms of biocompatibility, osteoconductivity, and patient outcomes. However, limitations such as low mechanical strength and the need for further research on long-term safety and efficacy were identified. This review underscores the potential of HaP in craniofacial surgery while highlighting areas for future investigation.

Hydroxyapatite Cement in Craniofacial Reconstruction

OBJECTIVES: To evaluate the long-term efficacy of hydroxyapatite cement in craniofacial reconstruction, specifically examining the role (if any) of radiation, implant location, and cement type.

STUDY DESIGN: A retrospective chart review was conducted of all patients presenting to the senior surgeon (Y.D.) for craniofacial reconstruction from September 1997 to April 2004.

METHODS: Data were collected including type of cement used, size of defect, complications, need for removal of cement, reason for defect, and pathologic results of examination of removed cements.

RESULTS: One hundred two patients were identified who underwent craniofacial reconstruction with hydroxyapatite cements, 7 of whom required complete implant removal (6 Norian and 1 Mimix), and 4 (2 Norian and 2 Bone source) of whom required partial implant removal for foreign body reaction. Five of the removals were in patients who underwent postoperative radiation.

CONCLUSIONS: Hydroxyapatite cements are safe in craniofacial reconstruction. The highest risk of implant infection comes from reconstruction in the area of the frontal sinus, immediately beneath coronal incisions, and in patients who receive postoperative radiation treatment. Based on our results, there does appear to be a statistically significant difference in rates of infection and foreign body reaction between the different types of hydroxyapatite cement. We would not recommend implantation of this material in contact with the frontal sinus. Caution should be exercised when it is placed directly beneath an incision or in patients receiving postoperative radiation, particularly if a boost dose is given.

EBM RATING: C

Anterior skull base surgery

The basic principle of anterior skull base surgery is to provide adequate exposure to enable three dimensional resection of skull base tumors. Negative surgical margins, which is within the control of surgeon, is the principle prognostic factor in anterior skull base tumors. Open skull base approaches is the standard of care for malignant anterior skull base tumors. Benign lesions may be resected by alternate minimally invasive approaches. Advances in anterior skull base surgery, in particular the facial translocation approaches allows wide exposure of the tumors with minimal retraction of the brain. The outcome of anterior skull base tumors have steadily increased over the years with disease free survival comparable to other malignant neoplasm of the head and neck region. This review described various surgical approaches and pertaining anatomy and pathology of anterior skull base tumors.

Use of precontoured positioning plates and pericranial flaps in midfacial reconstruction to optimize aesthetic and functional outcomes

OBJECTIVES

To present our experience with reconstruction of midfacial defects using "precontoured positioning plates" with or without pericranial flaps and to describe our technique in detail.

METHODS

Thirty-two consecutive patients with midfacial defects subsequent to oncologic resection that were reconstructed primarily with cranial bone grafts and precontoured positioning plates were reviewed for type of defect, functional outcome, complications, and postoperative appearance.

RESULTS

Primary reconstruction of all defects in this series was performed. Defects involved the orbital rim, orbital floor, or both in 28 patients (88%), the body of the zygoma in 24 patients (75%), and extended to the skull base in 16 patients (50%). Pericranial flaps were used to cover the bone grafts in 22 patients (69%). Postoperative radiotherapy was performed in 22 patients (69%), preoperative radiotherapy in 5 (16%), and the other 5 (16%) had no radiotherapy. There were no intraoperative complications, and postoperative complications included plate exposure (n = 2), ectropion (n = 3), and partial bone graft loss or resorption subsequent to completion of radiotherapy (n = 2). Postoperatively, appearance was excellent in 24 patients, fair in 6 patients, and poor in 2 patients. Secondary reconstructive procedures were performed in 4 patients (12%). Follow-up ranged from 12 months to 6 years (median, 4.2 years).

CONCLUSIONS

Precontoured positioning plates with or without pericranial flaps enable precise reconstruction of midfacial defects with precise incorporation of cranial bone grafts. In our series we routinely covered the bone grafts with well-vascularized tissues, leading to a low incidence of complications and excellent aesthetic results.

Orbitozygomatic Resection of Meningiomas of the Orbit

OBJECTIVE

To review our experience with the surgical treatment of orbital meningiomas.

METHODS

A retrospective review of all patients presenting to the author for treatment of orbital meningiomas over a 5 year period with a minimum of 1 year follow-up were included in this review. Demographic data, surgical approaches, and recurrence rates were documented.

RESULTS

A total of seven patients were treated for this condition. Complete surgical resection was achieved with the outlined technique in 71% of the patients, and gross tumor removal was achieved in the remaining 29% of patients. This latter group received postoperative gamma-knife treatment, and only a single patient has evidence of persistent disease that is nonprogressive at 3-year follow-up.

CONCLUSIONS

Meningioma of the orbit, whether primary (ectopic) or secondary. should be treated as at other sites with complete surgical excision if possible. Gamma knife or intensity modulated radiotherapy may be useful for residual microscopic disease. Surgical clearance is facilitated with the broad field exposure afforded by the orbitozygomatic approach outlined in the article, with particular attention directed at positive identification of key landmarks particularly in retro-orbital and cavernous sinus extension.

Skull base reconstruction

Reconstruction of skull base defects following tumor resection is of paramount importance in avoiding serious and life-threatening complications. Cranial base surgery has evolved and outcomes have steadily improved as increasingly reliable reconstructive techniques have been adapted to repair the challenging wounds in this complex anatomic region. The most significant development has been the introduction and refinement of microvascular free tissue transfer to the skull base over the past 15 to 20 years. Free flaps can reliably provide the requisite tissue to not only seal the intracranial space from the subjacent cavities, but also to restore complex craniofacial defects that often result from skull base tumor excision. Advances in alloplast technology have also expanded the armamentarium available to the reconstructive surgeon. In particular, bone substitutes, titanium hardware, and resorbable plate fixation have been shown to be very efficacious when used in carefully selected situations. Finally, tissue sealants and adhesives have become widely used as an adjunctive method to achieve a water-tight dural repair.