3D visualization and simulation in surgical planning system of orbital hypertelorism

Surgical Planning of Sacral Nerve Stimulation Procedure in Presence of Sacral Anomalies by Using Personalized Polymeric Prototypes Obtained with Additive Manufacturing Techniques

Sacral nerve stimulation or sacral neuromodulation involves the implantation of a stimulating electrode lead through the sacral foramina. In patients with anatomical sacral anomalies, it can constitute a challenging procedure due to a lack of common reference points present in the normal anatomy. In this study, we present an innovative application of additive manufacturing for the planning of sacral nerve stimulation techniques and related surgical procedures in complex cases, and we verify that the use of personalized patient models may help to manage the presence of sacral anomalies. The use of two alternative additive manufacturing technologies working with thermoplastic and thermoset polymers, including fused deposition modeling as low-cost alternative and laser stereolithography as industrial gold standard, is compared in terms of viability, precision and overall production costs. They pay special attention to fidelity in terms of the bone microstructure reconstruction, which is necessary for adequately planning electrode insertion. Advantages and limitations of the alternative approaches are discussed and ideas for future developments and for solving current challenges are presented.

Controversy on the Age of Hypertelorism Correction

INTRODUCTION

Orbital hypertelorism (HTO) is a challenging craniofacial problem seen in association with some congenital deformities. The age of HTO correction is a matter of debate.

THE AIM OF THE WORK

to evaluate the outcome of HTO correction and determine the optimal timing for intervention, striving for the earliest possible intervention with the lowest relapse.

PATIENTS AND METHODS

A standard craniofacial approach with medial bone resection, 4 walls orbital box osteotomy and orbital medialization were done for all patients. Skeletal and soft tissue procedures were done as indicated.

RESULTS

there were 10 patients aging 6 to 19 years. Seven were associated with craniofacial clefts, and 3 with craniosynostosis syndromes. HTO was severe in 8 cases and moderate in 2 cases. It was asymmetric in 2 cases. Frontoorbital remodeling was done in 3 cases with craniosynostosis. Failed surgery was reported in 2 cases. A redo surgery was done for one of them with an excellent outcome, while refused by the other. Nine patients had an excellent outcome. The mean level of satisfaction was 93.37%. Three patients had ugly facial scars. No major complications were recorded.

CONCLUSION

The time for surgical treatment of HTO is determined by the severity of the associated deformity. If there is an urgent factor indicating intervention, early correction can be performed exceptionally; otherwise, HTO correction should be performed after the age of 6 years.

Surgical correction of grade III hypertelorism

Orbital hypertelorism is an increased distance between the bony orbits and can be caused by frontonasal malformations, craniofacial clefts, frontoethmoidal encephaloceles, glial tumors or dermoid cysts of the root of the nose, and various syndromic or chromosomal disorders. We report a series of 7 cases of hypertelorism that were treated in our hospital. The underlying causes in our series were craniofacial clefts 0 to 14 (4 cases), craniofacial clefts 1 to 12 (1 case), and frontonasal encephalocele (2 cases), all congenital. Surgical techniques used to correct the deformity were box osteotomy and medial wall osteotomy with or without calvarial and rib grafts. A few of our cases were reoperations with specific challenges.

Application of computer techniques in repair of oblique facial clefts with outer-table calvarial bone grafts

OBJECTIVE

This study focused on the application of computer-aided and rapid prototyping techniques in the repair of oblique facial clefts with outer-table calvarial bone.

METHODS

Five patients with oblique facial clefts underwent repair with outer-table calvarial bone. A mirror technique and rapid prototyping techniques were applied to design and prefabricate the individualized template for the preoperative repair of orbital inferior wall and maxillary anterior wall defects. Using computer software, the ideal region from which to take outer-table calvarial bone was located according to the size and surface curvature of the individualized template. During the operation, outer-table calvarial bone was fixed according to the shape of the individualized template, and bone onlay grafting was carried out after appropriate trimming. Surgical accuracy was evaluated by comparing the preoperative and postoperative 3-dimensional reconstructed images.

RESULTS

With computer-aided and rapid prototyping techniques, all 5 patients had an ideal clinical outcome with few complications. The 3-dimensional preoperative design images and postoperative images fit well. Six-month to 8-year postoperative follow-up demonstrated that 4 patients had good aesthetic facial appearances and 1 had developed recurrence of lower eyelid shortage.

CONCLUSIONS

Computer-aided and rapid prototyping techniques can offer surgeons the ability to accurately design individualized templates for craniofacial deformity and perform a simulated operation for greatly improved surgical accuracy. These techniques are useful treatment modalities in the surgical management of oblique facial clefts.

The value of three-dimensional printing modelling for surgical correction of orbital hypertelorism

Orbital hypertelorism is defined as an increased distance between both medial and lateral sides of the orbits. Most common causes are frontonasal malformations, craniofacial fissures, encephalocele and a miscellaneous group of various syndromic or chromosomal disorders. Surgical correction of orbital hypertelorism is still challenging. The present report describes a case of severe orbital hypertelorism of an 11-year-old boy, where surgical correction was planned using three-dimensional printing modelling. This approach allowed reducing time of surgery, accurately planning the location of the osteotomies and precontouring the osteosynthesis material. Three-dimensional models are very helpful tools in planning complex craniofacial operative procedures.