A new modification of the individually designed polymer implant visible in X-ray for orbital reconstruction

Clinical application of biomaterials in orbital implants: a systematic review

PURPOSE

Various materials have been proposed for reconstructing orbital fractures. The materials used must meet certain criteria to ensure their suitability for restoring the structure and function of the organ. These criteria include biocompatibility, ease of application, non-toxicity, hypo-allergenicity, and non-carcinogenicity. In this study, we systematically reviewed the studies regarding the biomaterials in orbital implants and their clinical application.

METHODS

A comprehensive search across various databases, including PubMed, Scopus, EMBASE, Cochrane Library, and Web of Science, was conducted until April 10th, 2023. After retrieving the search results and eliminating duplicates, final studies were included after screening through defined criteria. Human and animal studies assessing the clinical application of biomaterials in orbital implants were included. The quality of the case series and controlled intervention studies were evaluated using the NIH tool, and for animal studies, the risk of bias was assessed using SYRCLE's tool.

RESULTS

Seventeen studies were included according to defined criteria. These studies aimed to explore the clinical application of biomaterials and examine the associated complications in orbital implants.

CONCLUSION

We found that using biomaterials did not result in elevated intraocular pressure (IOP). However, we did observe certain complications, with infection, residual diplopia, and enophthalmos being the most frequently reported issues.

Measures of Corticalization

After the insertion of dental implants into living bone, the condition of the peri-implant bone changes with time. Implant-loading phenomena can induce bone remodeling in the form of the corticalization of the trabecular bone. The aim of this study was to see how bone index (BI) values behave in areas of bone loss (radiographically translucent non-trabecular areas) and to propose other indices specifically dedicated to detecting corticalization in living bone. Eight measures of corticalization in clinical standardized intraoral radiographs were studied: mean optical density, entropy, differential entropy, long-run emphasis moment, BI, corticalization index ver. 1 and ver. 2 (CI v.1, CI v.2) and corticalization factor (CF). The analysis was conducted on 40 cortical bone image samples, 40 cancellous bone samples and 40 soft tissue samples. It was found that each measure distinguishes corticalization significantly (p < 0.001), but only CI v.1 and CI v.2 do so selectively. CF or the inverse of BI can serve as a measure of peri-implant bone corticalization. However, better measures are CIs as they are dedicated to detecting this phenomenon and allowing clear clinical deduction.

The influence of concomitant medial wall fracture on the results of orbital floor reconstruction

INTRODUCTION

Up to 35% of orbital floor fractures extend to the medial wall. This results in restriction of both abduction and adduction, leading to horizontal diplopia. The greater the defect, the more pronounced the enophthalmos.

AIM OF THE STUDY

The aim of the study was to determine the influence of concomitant medial wall defects on enophthalmos and diplopia, and the influence of intraoperative revision on the results of surgical reconstruction in patients with orbital floor fracture.

MATERIAL AND METHODS

78 cases of orbital floor fracture, with or without concomitant medial wall defect, were retrospectively analyzed. Reconstruction surgeries were performed in a similar fashion, but with variation in the alloplastic materials used. Careful investigation of the area was performed during the surgery.

RESULTS

Patients with associated medial wall defects had significantly more pronounced enophthalmos than those with isolated floor fracture, with no such difference after the orbital reconstruction. Postoperative vertical diplopia was more common in patients with an associated medial defect.

CONCLUSIONS

Associated medial wall defect leads to more severe enophthalmos at presentation. However, if the medial aspect of the orbital wall is revised properly, postoperative outcomes are not inferior to those in cases of isolated floor fracture.

Radio-opaque polyethylene for personalized craniomaxillofacial implants

OBJECTIVE

This study aimed to present a new possibility to create radio-opaque implant material for craniomaxillofacial reconstruction.

MATERIALS AND METHODS

The test disks made of the own compound of polyethylenes with addiction of 2, 4, and 6 % of weight TiO₂ was investigated for cytotoxicity [each group 15 disks respectively]. Next, computed tomography of the disks was performed in environment of muscle and fat. Hardness, tensile modulus and strength, and compressive modulus and strength were tested too.

RESULTS

Deterioration of mechanical properties of the composites containing titanium dioxide was observed [hardness, tensile modulus and strength, compressive modulus and strength, respectively: 56.7 ± 1.6 shore D, 354 ± 52, 22.5 ± 1.3, 21.8 ± 1.1, and 2995 ± 327 MPa as addiction of 2 % TiO₂; 52.0 ± 0.9 shore D, 347 ± 66, 18.0 ± 0.7, 14.2 ± 0.9, and 1396 ± 477 MPa as 4 % TiO₂; 51.3 ± 1.3 shore D, 316 ± 9, 17.4 ± 0.2, 13.6 ± 0.6, and 1100 ± 144 MPa as 6 % TiO₂ added]. The test disks revealed no cytotoxicity effect on human osteoblasts. The new material presents mild radio-opacity which was enough to observe the implant in relation to fat and muscle, but with no visible effect of beam hardening.

CONCLUSION

In view of the performed tests, the polyethylene enriched by titanium dioxide seems to be a proper material to consider manufacturing of craniomaxillofacial implants.

CLINICAL RELEVANCE

Maxilloafacial surgery is still looking for new implantologic materials. The proposed one is a new way to manufacture an implant visible in computed tomography which does not interfere with its shape in radiological examination and makes it possible to observe the surrounding soft tissues.

Surgical management of upgaze diplopia in patients after posttraumatic orbital floor reconstruction

OBJECTIVE

The most common complication of otherwise successful reconstructive surgery of a fractured orbital floor is persistent diplopia. For patients with troublesome double vision in upgaze, a reasonable solution is offered by strabismus surgery. The aim of our study is to examine the results of extraocular muscle surgery in cases of diplopia that persisted in upgaze after posttraumatic orbital floor reconstruction.

MATERIAL AND METHODS

In this study we present a retrospective series of 24 patients with troublesome vertical diplopia in upgaze. In all cases, the surgery consisted of a posterior fixation suture placement on the contralateral superior rectus muscle with or without its recession. Full orthoptic examination was conducted before and 3 months after the surgery.

RESULTS

Postoperatively 19 patients (79%) were diplopia free and 6 (21%) had vertical diplopia in extreme upgaze. The field of binocular single vision improved threefold. None of the patients reported diplopia in the primary position or in any position other than upgaze.

CONCLUSION

Vertical incomitant strabismus and diplopia in upgaze persisting after orbital reconstructive surgery may be corrected surgically. Contralateral posterior fixation of the superior rectus muscle, with or without its recession, appears to be an effective procedure for use in these patients.