Cranial nerve injuries in Le Fort I osteotomy: a systematic review

Cranial Nerve Injuries in Orthognathic Surgery: A Review of Literature

ABSTRACT

Orthognathic surgery is increasingly utilized to correct facial deformities and dental malocclusions, as well as to enhance facial aesthetics. Significant advancements in surgical planning and execution have made it more widespread and accessible. However, unfavorable outcomes or complications can occur, leading to potentially severe and possibly long-term consequences, such as cranial nerve injuries. This literature review investigates the cranial nerve complications associated with orthognathic surgery. We conducted an extensive search across available databases, analyzing relevant studies published up to September 30, 2023. Two authors independently selected articles for full-text review based on their titles and abstracts. The eligible studies reported cranial nerve injuries in individuals who had undergone orthognathic surgery. Our findings highlight the risk of cranial nerve injuries, their possible mechanism, management, and outcomes. It is imperative for surgeons to remain vigilant and informed and to communicate such information during preoperative patient consultation.

Facial Palsy after Orthognathic Surgery: Incidence, Causative Mechanism, Management, and Outcome

BACKGROUND

Facial palsy after orthognathic surgery is an uncommon but serious complication causing dissatisfaction and affecting quality of life. The occurrence could be underreported. Surgeons need to recognize this issue regarding the incidence, causative mechanism, managements, and outcome.

METHODS

A retrospective review of orthognathic surgery records between January of 1981 and May of 2022 was conducted in the authors' craniofacial center. Patients who developed facial palsy after the surgery were identified, and demographics, surgical methods, radiologic images, and photographs were collected.

RESULTS

A total of 20,953 sagittal split ramus osteotomies (SSROs) were performed in 10,478 patients. Twenty-seven patients developed facial palsy, resulting in an incidence of 0.13% per SSRO. In a comparison of SSRO technique, the Obwegeser-Dal Pont technique using osteotome for splitting had higher risk of facial palsy than the Hunsuck technique using the manual twist splitting ( P < 0.05). The severity of facial palsy was complete in 55.6% of patients and incomplete in 44.4%. All patients were treated conservatively, and 88.9% attained full recovery in a median duration of 3 months [interquartile range (IQR), 2.75 to 6 months] after surgery, whereas 11.1% attained partial recovery. Initial severity of facial palsy predicted the timing of recovery, with incomplete palsy patients having faster median recovery (3 months; IQR, 2 to 3 months) than the complete palsy patients (6 months; IQR, 4 to 6.25 months) ( P = 0.02).

CONCLUSIONS

The incidence of facial palsy after orthognathic surgery was 0.13%. Intraoperative nerve compression was the most likely causative mechanism. Conservative treatment is the mainstay of therapeutic strategy, and full functional recovery was anticipated.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, IV.

Exploring the relationship between the number of systematic reviews and quality of evidence: an orthognathic surgery-based study

OBJECTIVE

We analyzed the quality and quantity of systematic reviews (SRs) of orthognathic surgery, the most frequently published topic in maxillofacial surgery.

STUDY DESIGN

We searched the PubMed database for SRs of orthognathic surgery with no restriction on the language of publication date. We assessed the certainty of evidence presented according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol and the Leiden Manifesto using the Grading of Recommendations Assessment, Development, and Evaluation approach. We analyzed the data using descriptive statistics, Pearson´s correlation test, and linear regression.

RESULTS

Of the 171 SRs evaluated, approximately one fifth presented evidence with a high level of certainty. The number of orthognathic surgery SRs has been increasing, and many SRs were published after very similar topics had already been published. There is no relationship between the impact factor and the certainty of evidence.

CONCLUSIONS

An excessive number of SRs of orthognathic surgery are published, and many SRs are superfluous, simply reporting previous findings. Clinicians should not base treatment decisions solely on the evidence presented in SRs, and journal editors and reviewers should evaluate these SRs more critically, particularly when they address topics that have already been covered in the literature.

Does mandibular osteotomy affect the infraorbital nerve? a prospective study

OBJECTIVES

The aim of this study was to evaluate the sensory function of the infraorbital nerve after orthognathic surgery (OS).

MATERIALS AND METHODS

Patients who underwent Le Fort I osteotomy with or without BSSO for dentofacial deformity treatment were studied. Two groups were created according to whether BSSO was performed. Class A tests were performed to determine the degree of peripheral nerve damage. The Class B test was performed if decreased sensation was detected in at least one of these tests. A Class C test was performed if abnormal sensation was detected.

RESULTS

Twenty-eight patients (n=56) who underwent OS were included in this prospective study. Of the patients, 57.1% were female, 42.9% were male, and the mean age was 24.6 (±3.8). Seven patients were in group 1 (n=14), and 21 patients were in group 2 (n=42). In both groups, there were statistically significant differences between T1 and T2 (p<0.001), and the mean NSD score at T2 was higher than that at T1. The mean NSD score in the single jaw group was higher than that in the double jaw group at all time points.

CONCLUSIONS

Bimaxillary surgeries had a negative effect on the somatosensory changes that developed in the early period. The upper lip's somatosensorial recovery was faster than IOR and single jaw recovery was faster than double jaw.

CLINICAL RELEVANCE

Maxillofacial surgeons performing orthognathic surgery should be aware that in double jaw operations, changes in the somatosensory function of the ION are more severe.

Evidence Mapping and Quality Analysis of Systematic Reviews on Various Aspects Related to Cleft Lip and Palate

BACKGROUND

Management of cleft lip and palate is interdisciplinary. An evidence-mapping approach was envisaged to highlight the existing gaps in this field, using only the highest level of evidence.

OBJECTIVES

To conduct evidence mapping and quality analysis of systematic reviews and meta-analyses related to any aspect of cleft lip and palate.

SEARCH METHODS

The cleft lip and palate field was divided into 9 domains and 50 subdomains and a method of categorization of systematic reviews was established. A comprehensive search strategy was carried out in seven databases along with the search of gray literature and references of included articles.

SELECTION CRITERIA

Systematic reviews related to any aspect of cleft lip and palate, conducted by a minimum of two reviewers, with a comprehensive search strategy and adequate quality analysis were included.

DATA COLLECTION AND ANALYSIS

A self-designed, pre-piloted data-extraction sheet was used to collect information that was analyzed through an expert group discussion. Quality analysis was performed using ROBIS-I, AMSTAR 2, and the PRISMA checklist.

RESULTS

A total of 144 systematic reviews published between 2008 and 2022 were included. The largest number of these could be categorized in the therapeutic domain (n = 58). A total of 27% of the studies were categorized as inconclusive, 40% as partially conclusive, and 33% as conclusive. As per ROBIS-I, 77% of reviews had high risk of bias while 58% were graded as critically low in quality as per AMSTAR 2. The majority of systematic reviews showed low reporting errors.

CONCLUSIONS

The majority of systematic reviews related to cleft lip and palate relate to therapeutic and prognostic domains and show high risk of bias and critically low quality regardless of the source journal. The results of this paper might serve as a starting point encouraging authors to carry out high-quality research where evidence is lacking.

REGISTRATION

A multidisciplinary expert-group formulated an a priori protocol, registered in Open Science Framework (DOI 10.17605/OSF.IO/NQDV2).

Facial palsy after orthognathic surgery: A systematic review

It was the aim of the systematic review to evaluate the incidence of facial palsy following orthognathic surgery, and to assess the possible mechanisms of injury, subsequent management, and eventual outcomes. The protocol of this systematic review was registered in the International Prospective Register of Systematic Reviews. A thorough search of PubMed, Scopus, Cochrane Library, and CINAHL databases up to April 2022 was conducted. In total, 34 articles were selected for this review, including 54 facial palsies in 53 patients. The incidence of facial palsy was estimated to range from 0.04% to 0.77%. Most of the possible etiologies proposed involved intraoperative nerve compression or postoperative edema. Physical therapy and steroid administration were the most frequently employed management approaches. Surgical exploration for the facial nerve was executed in one patient. Forty-three facial palsies (79.6%) attained complete recovery with conservative management, whereas 11 facial palsies (20.4%) continued to show incomplete recovery during the follow-up period. Earlier facial palsy onset (timing after surgery) was related to a higher risk of continuing palsy (p = 0.018). Within the limitations of this review it seems that facial palsy following orthognathic surgery should be treated conservatively whenever appropriate.

Stroke Due to Orthognathic Surgery: Case Report of a Rare Complication

Le Fort I osteotomy is a frequent surgical procedure used in orthognathic surgeries to treat severe malocclusions and is associated with relatively rare surgical complications. Here, the authors report a case of thrombotic ischemic stroke as a result of this procedure, a complication still not described in the literature. A 19-year-old man with class II malocclusion and retrognathia underwent orthognathic surgery for aesthetic purposes. The surgery included a Le Fort I maxillary osteotomy with vertical impaction, bilateral sagittal split ramus osteotomy for mandibular advancement, and genioplasty. Postoperatively, the patient developed left eye blindness, headache, somnolence, aphasia, and right hemiplegia. Medical imaging showed the Le Fort I line of fracture extending from the maxillary osteotomy to the left optic canal and to the left carotid canal, with osseous fragments impinging the petrous segment of the internal carotid artery, left carotid artery occlusion and associated to an ischemic stroke at the left middle cerebral artery territory. Treatment required decompressive craniectomy and later focused on clinical stabilization, infection management, orthognathic care, neurorehabilitation, and cranioplasty. The hemiplegia and aphasia partially recovered during 12 months, and final dental occlusion was appropriate. Our report demonstrates that an unfavorable Le Fort I fracture trajectory can lead to ischemic stroke and severe neurological deficits.

Factors Affecting Optic Nerve Damage in Le Fort III Osteotomy: A Retrospective Study

The causes of visual impairment following Le Fort osteotomy for syndromic craniosynostosis have not been completely elucidated. The authors investigated the potential causes and means of prevention of optic nerve damage, with particular emphasis on intraoperative blood transfusion volume and operating time. This retrospective study evaluated patients who underwent Le Fort III osteotomy for syndromic craniosynostosis between 2000 and 2020. Data on pupillary reflex, pupil size, operating time, blood transfusion, age at time of surgery, sex, and syndrome type were obtained from medical records. Univariate analysis and multivariate analysis with the level of statistical significance set at P<0.05. For the 86 patients included, the mean values of operating time, amount of blood transfusion based on body weight, amount of blood transfusion per body weight per hour, and age were 6.0 hours (range: 3.5-12.3 h), 30.5 mL/kg (range: 0-322 mL/kg), 5.14 mL/kg/h (range: 0-35.7 mL/kg/h), and 10.0 years (range: 4-38 y), respectively. Crouzon, Apert, and Pfeiffer syndromes were observed in 49, 29, and 8 patients, respectively. Abnormal pupillary findings were observed in 27 patients of whom 25 showed no abnormalities in subsequent visual function and 2 developed blindness. Abnormal pupillary findings correlated with the amount of blood transfused per body weight (P=0.0082) and amount of blood transfused per body weight per hour (P=0.0052). As demonstrated in this study, increased intraoperative bleeding and amount of blood transfused were associated with optic nerve damage, particularly during acute bleeding. Prompt inspection of the pupils following surgery is therefore warranted.

Evaluating Morphology of the Pterygomaxillary Junction and Its Association With the Orbit in Different Facial Skeletal Relationships

PURPOSE

The etiology for blindness after Le Fort I osteotomy is poorly understood. The authors propose that a study of the morphology and anatomical relationship of the pterygomaxillary junction to orbital vital structures may be crucial for understanding the possible etiology.

MATERIALS AND METHODS

This retrospective observational study involved analysis of data procured from computed tomography scans of individuals who were categorized into 4 groups based on their skeletal characteristics: skeletal Class I, II, and III and cleft lip palate (CLP). The outcome variables included i) the height, width, and thickness of the pterygomaxillary junction (PTMJ) which represent its morphology and ii) distance of the PTMJ to the superior orbital fissure and optic canal, to demonstrate its proximity to orbital vital structures. Primary outcome measures were to i) compare variance of the outcome variables across groups, ii) determine association between PTMJ morphology and its proximity to the orbit, and iii) determine association between skeletal morphology and the outcome variables. Data were analyzed using descriptive and inferential statistics to study variance and association.

RESULTS

Forty patients (80 sides) were divided into 4 groups. The CLP group demonstrated maximum height and thickness of the PTMJ, whereas the Class II group demonstrated the minimum (P < .001 and P = .001, respectively). The CLP group demonstrated the closest proximity of the PTMJ to orbital vital structures (P < .001), with Class II being the farthest (P < .001). There was a weak positive correlation between the PTMJ height and its thickness and width, whereas a moderate negative correlation was seen between the PTMJ height and its distance from the optic canal and superior orbital fissures (P < .001).

CONCLUSIONS

Morphology of the PTMJ varies with facial skeletal relationship and also influences the relationship of the PTMJ with the orbital vital structures. This may be critical in understanding the pathophysiology of blindness after Le Fort I osteotomies.

A new pattern of cranial nerve injuries caused by unfavorable fractures during Le Fort I osteotomy

Cranial nerve injury is a described complication of Le Fort I osteotomy technique. The authors present the case of a 45-year-old patient that underwent bimaxillary orthognathic surgery and suffered unfavorable skull base fractures, which resulted in cranial nerve injury of the II, III, IV, V, and VI nerves on the left side and of the V nerve on the right side, through different mechanisms. One of the mechanisms was cavernous sinus thrombosis, which was never described following Le Fort I technique in a non-cleft patient. The fracture pattern involved the foramen ovale and Meckel's cave, which was also never described after this technique. The resolution of the deficits at the final follow-up at 14 months was incomplete. Le Fort I osteotomy technique is considered a safe technique to correct dentofacial deformities, but serious complications can occur. Pterygomaxillary disjunction and down-fracture must be performed with the utmost care to avoid it.

Effect of maxillary advancement on speech and velopharyngeal function of patients with cleft palate: Systematic Review and Meta-Analysis

This systematic review (SR) aimed to evaluate speech and velopharyngeal function (VPF) changes of patients with cleft palate (CLP) after maxillary advancement (MA) surgery. A two-phase PROSPERO-registered SR (CRD42019141370) was conducted following the PRISMA statements. Search strategies were developed for main databases (PubMed, Scopus, Web of Science, COCHRANE, LILACS, and EBSCOhost) and Grey literature information sources. The GRADE tool was used to evaluate the quality of evidence. From a total of 908 articles, 10 (205 men and 147 women; mean age ranging from 18.0 to 25.7 years) were selected for meta-analysis. Moderate to high risk of bias (Rob) was observed. The most common methods for outcomes evaluation were the Nasometer (speech) and nasoendoscopy (VPF). Speech changed from normal to hypernasal, and VPF worsening were reported in most studies. Comparing maxillary advancement interventions (osteogenic distraction versus Le Fort I), no statistically significant differences were found regarding benefit on speech and VPF. In summary, the effect of MA on speech and VPF remains controversial in CLP patients. The RoB, inconsistencies, and imprecisions severely affected the overall quality of evidence. Further adequately delineated clinical studies are necessary to investigate the potential effect of MA interventions on speech and VPF in CLP patients.