Critical appraisal of patient-specific implants for secondary post-traumatic orbital reconstruction.

In orbital reconstruction, a patient-specific implant (PSI) may provide accurate reconstruction in complex cases, since the design can be tailored to the anatomy. Several design options may be embedded, for ease of positioning and precision of reconstruction. This study describes a cohort of 22 patients treated for secondary orbital reconstruction with a PSI; one patient received two PSI. The preoperative clinical characteristics and implant design options used are presented. When compared to preoperative characteristics, the postoperative clinical outcomes showed significant improvements in terms of enophthalmos (P < 0.001), diplopia (P < 0.001), and hypoglobus (P = 0.002). The implant position in all previous reconstructions was considered inadequate. Quantitative analysis after PSI reconstruction showed accurate positioning of the implant, with small median and 90th percentile deviations (roll: median 1.3°, 90th percentile 4.6°; pitch: median 1.4°, 90th percentile 3.9°; yaw: median 1.0°, 90th percentile 4.4°; translation: median 1.4 mm, 90th percentile 2.7 mm). Rim support proved to be a significant predictor of roll and rim extension for yaw. No significant relationship between design options or PSI position and clinical outcomes could be established. The results of this study show the benefits of PSI for the clinical outcomes in a large cohort of secondary post-traumatic orbital reconstructions.

[Loss of an eye as a result of an odontogenic infection]. / Oogverlies als gevolg van een dentogene infectie.

A 50-year-old woman presented at the outpatient clinic of the department of oral and maxillofacial surgery with a severe swelling around the left eye 1 week after removal of the second molar in the upper jaw. Despite administration of antibiotics 2 days after the removal of the molar because of periorbital swelling, the inflammation spread to the intraorbital space with eventual loss of the left eye. Timely recognition of the symptoms of (the onset of) an orbital infection after dental treatment and immediate referral to an oral and maxillofacial surgeon and/or ophthalmologist for adequate treatment can be vision-saving. Fortunately, orbital infections with an odontogenic cause are rare.

Intraoperative imaging in orbital reconstruction: how does it affect the position of the implant?

Intraoperative imaging enables the surgeon to control the position of the implant during orbital reconstruction. Although it might improve surgical outcome and avoid the need for revision surgery, it may also increase the duration of the operation and the exposure to radiation. The goal of this study was to find out whether intraoperative imaging improves the position of the implant in reconstructions of the orbital floor and medial wall. Two surgeons reconstructed complex orbital fractures in 10 cadavers. After the reconstruction a computed tomographic scan was made to confirm the position of the implant and, if required, to make any adjustments. Scans were repeated until the surgeon was satisfied. The ideal position was ascertained by scans that were obtained before and after creation of the fractures. The position of the implant achieved was compared with that of the ideal position of the implant, and improved significantly for yaw (p=0.04) and roll (p=0.03). A mean of 1.6 scans was required for each reconstruction (maximum n=3). The main reason for alteration was the rotation roll. Intraoperative imaging significantly improves the position of the implant in fractures of the orbital floor and medial wall. The surgeon has quality control of its position during the reconstruction to restore the anatomical boundaries.

Are there risk factors for osseous mandibular inferior border defects after bilateral sagittal split osteotomy?

PURPOSE: Bone defects of the inferior mandibular border (osseous inferior border defects) can cause unesthetic postoperative outcomes after bilateral sagittal split osteotomy (BSSO). The aim of this study was to estimate the frequency of osseous inferior border defects after BSSO and to identify risk factors for this complication. MATERIALS AND METHODS: This retrospective study included consecutive patients who underwent BSSO for mandibular retrognathia. The primary outcome was the presence/absence of osseous inferior border defects. Predictors included the mandibular movement, rotation of the occlusal plane, postoperative proximal segment position, pattern of lingual fracture, occurrence of bad split, and presence of third molars. RESULTS: The study sample consisted of 200 patients and had a mean follow-up of 13 months. The mean mandibular advancement and rotation was respectively 5.8 mm and 5.4° clockwise. Osseous inferior border defects were present in 7.0% of splits and in 12.5% of patients. Significant risk factors for inferior border defects included increased advancement, increased clockwise rotation, cranial rotation of the proximal segment, and a split originating in the lingual cortex. CONCLUSION: In conclusion, osseous inferior border defects occur significantly more often in cases with large mandibular advancement, increased clockwise rotation of the occlusal plane, malpositioning of the proximal segment, and a split originating in the lingual cortex.

Coronectomy of the mandibular third molar: Respect for the inferior alveolar nerve.

The aim of this study was to evaluate the outcomes of coronectomy as an alternative surgical procedure to complete removal of the impacted mandibular third molar in patients with a suspected close relationship between the tooth root(s) and the mandibular canal. A total of 151 patients underwent coronectomy and were followed up with clinical examinations and panoramic radiographs for a minimum of 6 months after surgery. None of the patients exhibited inferior alveolar nerve injury. Eruption of the retained root(s) was more frequent in younger patients (18-35 years). Thirty-six patients (23.8%) exhibited insufficient growth of new bone in the alveolar defect, and 11.3% required a second surgical procedure to remove the root remnant(s). Our results indicate that coronectomy can be a reliable alternative to complete removal of the impacted mandibular third molar in patients exhibiting an increased risk of damage to the inferior alveolar nerve on panoramic radiographs.

Controversies in orbital reconstruction-III. Biomaterials for orbital reconstruction: a review with clinical recommendations.

The goal of orbital reconstruction is to repair trauma defects, to correct the position of the eye anatomically, avoiding enophthalmos, and to restore ocular function. For the reconstruction of (trauma) defects, many surgeons recommend materials that can be bent into an anatomical shape and that possess the properties of radiopacity and long-term stability. However, apart from these desired properties, the ideal material for orbital reconstruction remains controversial. Autologous bone is often mentioned as the 'gold standard,' likely because of its mechanical properties, revascularization potential, and its adaptation to the orbital tissue with minimal acute and chronic immune reactivity. However, autologous bone can show unpredictable resorption rates and suboptimal volume correction. In recent years, an increasing interest in the use of alloplasts for orbital reconstruction has become apparent in the literature. Modern technological advantages, such as preoperative planning, navigation, and perioperative imaging, can be beneficial in the decision to choose a certain implant. The aim of this review is to give a comprehensive overview of the advantages and disadvantages of materials used to reconstruct traumatic orbital defects and to provide a practical, evidence-based, complexity-driven set of guidelines.

Controversies in orbital reconstruction--I. Defect-driven orbital reconstruction: a systematic review.

In the 1980s, computed tomography was introduced as an imaging modality for diagnosing orbital fractures. Since then, new light has been shed on the field of orbital fracture management. Currently, most surgeons are likely to repair orbital fractures based on clinical findings and particularly on data obtained from computed tomography scans. However, an important but unresolved issue is the fracture size, which dictates the extent and type of reconstruction. In other fields of trauma surgery, an increasing body of evidence is stressing the importance of complexity-based treatment models. The aim of this study was to systematically review all articles on orbital reconstruction, with a focus on the indication for surgery and the defect size and location, in order to identify the reconstruction methods that show the best results for the different types of orbital fractures.

Controversies in orbital reconstruction--II. Timing of post-traumatic orbital reconstruction: a systematic review.

The timing of orbital reconstruction is a determinative factor with respect to the incidence of potential postoperative orbital complications. In orbital trauma surgery, a general distinction is made between immediate (within hours), early (within 2 weeks), and late surgical intervention. There is a strong consensus on the indications for immediate repair, but clinicians face challenges in identifying patients with minimal defects who may actually benefit from delayed surgical treatment. Moreover, controversies exist regarding the risk of late surgery-related orbital fibrosis, since traumatic ocular motility disorders sometimes recover spontaneously and therefore do not necessarily require surgery. In this study, all currently available evidence on timing as an independent variable in orbital fracture reduction outcomes for paediatric and adult patients was systematically reviewed. Current evidence supports guidelines for immediate repair but is insufficient to support guidelines on the best timing for non-immediate orbital reconstruction.

Bilateral sagittal split osteotomy in cadaveric pig mandibles: evaluation of the lingual fracture line based on the use of splitters and separators.

OBJECTIVE: To analyze the splitting pathways of the (lingual) fracture lines during a bilateral sagittal split osteotomy (BSSO) in cadaveric pig mandibles. STUDY DESIGN: A BSSO was performed using splitters and separators. Special attention was paid to end the horizontal medial cut at the deepest point of the entrance of the mandibular foramen. RESULTS: Of all lingual fractures, 95% ended in the mandibular foramen. Forty percent of these fractures extended through the mandibular canal and 40% extended inferiorly along the mandibular canal. CONCLUSION: Almost all lingual fracture lines ended in the mandibular foramen, most likely due to the placement of the medial cut in the concavity of the mandibular foramen. The mandibular foramen and canal could function as the path of least resistance in which the splitting pattern is seen. We conclude that a consistent splitting pattern was achieved without increasing the incidence of possible sequelae.

Bilateral sagittal split osteotomy in a mandible previously reconstructed with a non-vascularized bone graft.

We report a bilateral sagittal split osteotomy (BSSO) in a reconstructed mandible. A 28-year-old woman underwent a segmental mandibulectomy due to a multicystic ameloblastoma in the left jaw. After primary plate reconstruction, final reconstruction was performed with a left posterior iliac crest cortico-cancellous autograft. Due to a pre-existing Class II malocclusion, the patient was analyzed for combined orthodontic-surgical treatment. Subsequently, after 1 year of orthodontic treatment, the BSSO was planned. The sagittal split was performed in the remaining right mandible and on the left side in the iliac crest cortico-cancellous autograft. Ten months later, oral rehabilitation was completed with implant placement in the neomandible. Follow-up showed a Class I occlusion, with good function. The patient was very satisfied with the functional and aesthetic results. This case shows that a BSSO can be performed in a reconstructed mandible, without side effects and with good functional and aesthetic results.

Surgical margins for resection of squamous cell carcinoma of the lower lip.

A prospective study was undertaken to evaluate the efficacy of 3 mm margins of resection with surgical excision of squamous cell carcinoma of the lower lip (SCCLL) in its early stages whereby the margins were checked with the systematic use of frozen-section examination. During the period of 1991-1998, 72 consecutive patients with a primary stage I/II SCCLL underwent surgical excision as the initial treatment. There were 58 males (81%) and 14 females (19%) with a median age of 66.8 years (range 37-91 years). The majority of cases (94.4%) were stage I tumours. Treatment consisted of a full-thickness excision including a 3 mm margin of clinically uninvolved tissue. Intraoperative frozen-section analysis of the margins of the excised specimen was used to confirm tumour-free margins. Clinically determined margins were tumour-free in 89.9% on initial excision. The false-positive rate associated with frozen-section analysis was 1.4%. The minimum follow-up period for all patients was 2 years (median 5.1 years, range 2-9 years). Local recurrence was found in two patients (2.8%). A 3 mm margin with excision of early SCCLL seems to be appropriate, if the margins are controlled by systematic use of frozen-section analysis.