Does encountering the facial nerve during surgical management of mandibular condylar process fractures increase the risk of facial nerve weakness? A systematic review and meta-regression analysis

Purpose

The purpose of this study was to identify whether the incidence of systematically identified or incidentally encountered facial nerve branches during dissection to approach condylar fractures increases risk of transient and/or permanent facial nerve weakness.

What factors affect the attachment of the inferior alveolar nerve to the buccal plate following sagittal split osteotomy?

PurposeThis study aimed to assess the factors that can possibly affect the positioning of the inferior alveolar nerve (IAN) in the proximal or distal segment following sagittal split osteotomy (SSO).Materials and methodsThis was a prospective cohort study. The patients were assigned according to the position of the IAN: the IAN was attached to the buccal plate in group 1 (27 SSOs), while it was in the distal segment in group 2 (83 SSOs).ResultsThe mean of the buccolingual thickness of the proximal segment at the vertical cut of the osteotomy (BLTP) was 5.0 ± 0.62 mm in group 1 and 4.16 ± 0.72 mm in group 2. The mean of the distance between the IAN and the external cortical bone at the distal of the second molar before the osteotomy (IANB) was 0.5 ± 0.24 mm in group 1 and 1.24 ± 0.45 mm in group 2. There were significant differences for the mean BLTP and IANB between the two groups (P = 0.001).ConclusionIt seems that the thickness of the buccal plate of the proximal segment, the distance from the IAN to the external cortical bone, the osteotomy technique, and the presence or absence of impacted third molars may be associated with the positioning of the IAN following SSO.     

Effects of electrical stimulation of the sympathetic nerve on the levels of β-adrenergic and cholinergic muscarinic receptors and cyclic nucleotides in rat salivary glands

After 30 and 60 min of stimulation, there were decreases of 16 to 19 per cent in β-adrenoceptors in rat submandibular and parotid glands; a 10-min stimulation caused no change. Pre-incubation of the reaction mixtures (stimulated glands) with atenolol, a β₁-antagonist, prevented most dihydroalprenolol (DHP) binding, but with butoxamine, a β₂-antagonist, DHP binding was nearly complete. Thus the β-receptor was of the β₁-subtype. Muscarinic receptors of parotid gland showed no change after 10 min stimulation; after 30 min there was an increase of 12 per cent, and after 60 min, of 28 per cent. With submandibular gland, there was also no change at 10 min but, at 30 min, there was a 25 per cent increase, and at 60 min, a decrease of 18 per cent. Cyclic-AMP levels of parotid gland were markedly elevated after 10 min of stimulation (9-fold increase above controls) but, at 30 and 60 min, there was only a 1.6-fold increase. In submandibular gland, cyclic-AMP increased 10-fold at 10 min; at 30 min it was 2.5 times control levels and at 60 min, 1.9 times. Cyclic-GMP levels of parotid gland increased 34-fold after 30 or 60 min of nerve stimulation, but only 1.6-fold at 10 min. With submandibular gland, there was a 22-fold increase at 10 min, but at 30 and 60 min this was 15- and 12-fold, respectively. Thus β-adrenergic and muscarinic receptor densities and levels of cyclic AMP and CMP change after acute stimulation of the sympathetic nerve to the rat salivary glands; increases in levels of both nucleotides precede the changes in receptor number.     

Is MRI a viable alternative to CT/CBCT to identify the course of the inferior alveolar nerve in relation to the roots of the third molars?

Clinical Oral Investigations - To assess the reliability of judging the spatial relation between the inferior alveolar nerve (IAN) and mandibular third molar (MTM) based on MRI or CT/CBCT images....     

Does 3-dimensional imaging of the third molar reduce the risk of experiencing inferior alveolar nerve injury owing to extraction?: A meta-analysis

Background

Clinicians generally use panoramic radiographic (PR) images to assess the proximity of the mandibular third molar to the inferior alveolar nerve (IAN). However, in cases in which a patient needs to undergo a third-molar extraction, many clinicians also assess computed tomographic (CT) images to prevent nerve damage.

Periodontal intraligament injection as alternative to inferior alveolar nerve block—meta-analysis of the literature from 1979 to 2012

Objectives

In a first meta-analysis, inferior alveolar nerve block (IANB) and periodontal intraligamentary injection anesthesia (ILA) were compared with focus on the failure rate of local anesthesia, pain during injection, additional injections, cardiovascular disturbances (CVD), and method-inherent differences (unwanted side effects, latency time, amount of anesthetic solution, duration of anesthesia) in adult patients.

Materials and methods

Prospective and retrospective studies with clinical comparison of both injection techniques considering the relevant outcome parameters in adult patients from 1979 to 2012 were included. A specific tool for assessing risk of bias in each included study was adopted. Data were assessed for methodological reliability and extracted and supplemented by sensitivity analysis by two independent reviewers.

Results

Seven studies were included [evidence grade Ib (n?=?1), IIb (n?=?3), and III (n?=?3)]. For other parameter than CVD, the significant heterogeneity of the random effects did not allow the reporting of pooled summary effect estimates. CVD were found significantly more often after IANB [odds ratio (OR): 0.12 (0.02–0.69)]. Further analysis revealed less injection pain in cases of ILA [OR: 0.32 (0.1–1)]. For failure rates as well as for needed additional injections, no significant differences were detected. IANB showed a latency of >3 min, whereas ILA had nearly none. The effect of IANB is longer than for ILA.

Conclusions

Methodological and reporting flaws were consistently observed in the included articles. Except for CVD, it could not be shown that ILA is neither superior nor inferior compared to IANB.

Clinical relevance

IANB as “gold standard” for routine dental treatments should be discussed.     

How do I manage an acute injury to the facial nerve?

Paralysis of the facial nerve is a cause of considerable functional and aesthetic disfigurement. Damage to the upper trunk can result in eye complications with the risk of exposure keratitis. Numerous factors influence the therapeutic strategy: the cause of the injury, the time elapsed since injury, functional impairment, and the likelihood of recovery. We discuss the management of an acute injury to the facial nerve and focus on the surgical options.     

Could skin retraction incision minimize nerve injury over the iliac crest?

The aim of this study is to elucidate the nerve passage over the iliac crest shifted by skin retraction in harvesting iliac bone graft. A total of 44 iliac crests obtained of 22 nonembalmed Korean fresh cadavers were dissected (six males and 16 females; age range, 57-91 years). In A group (22) of "reposed skin," a skin incision was made from the anterior superior iliac spine (ASIS) to the highest level of iliac crest (HLIC). In B group (22) of "medial retraction," skin was tugged medially 1.5 cm and an incision was made from ASIS to HLIC. In A group, the nerve branches were injured in 19 (86.4%) and 15 (68.2%) in B group. Most injured nerves crossed over the iliac crest and at the posterior half site of ASIS to HLIC. The involved nerves were the subcostal nerve, iliohypogastric nerve, and ilioinguinal nerve. Subcostal nerve was less inflicted with injury in B group (one branch, 4.5%) than A group (four branches, 18.2%). P value is 0.151. Iliohypogastric nerve was significantly least injured in B group (three branches, 13.6%) compared with A group (10 branches, 45.5%). P value is 0.022. An injuring rate of ilioinguinal nerve was almost the same between A group (13 branches, 59.1%) and B group (14 branches, 63.61%). P value is 0.760. In the procedure of harvesting iliac bone graft, it is suggested to make an incision on the skin retracted medially and on the anterior half site of ASIS to HLIC to avert an injury of superficial sensory nerves.     

Use of an 'osteocompressor' to avoid damage to the inferior alveolar nerve in the mandibular setback procedure: can the positive effects of osteodistraction be used in reverse? An experimental study in dogs

We have designed an osteocompressor to try and avoid damage to the inferior alveolar nerve during sagittal split setback osteotomy of the mandibular ramus, and tested it on the mandibles of 10 dogs. The osteocompressor bears a superficial resemblance to an osteodistractor, but has a different internal structure that allows it to compress rather than distract. We were able to compress the neurovascular canal, the neurovascular bundle, the cancellous bone, and the mandible in dogs at a rate of 1 mm/day by rotating the screw of the compressor 1.5 times. We conclude that in dogs the neurovascular canal and neurovascular bundle can be compressed with this device without loss of sensation. We believe that this is the first publication on nerve canal compression and osteocompression.     

What is the relation between the presence of caries in the deciduous dentition and the chronology of the eruption of the permanent teeth?

Based on data obtained from a prospective epidemiological study in a random sample of 4468 Flemish children, accurate emergence ages for permanent teeth could be established. When data on permanent tooth emergence in different populations are compared, differences are most pronounced for premolars. Several authors hypothesised that this difference could be explained by a difference in caries experience in the primary molars. The purpose of this study was to quantify the effect of caries experience in a primary molar on the timing of emergence of its successor. The results indicate that the emergence of the premolars was accelerated by 2 to 8 months when its predecessor had been decayed and or filled but had not been extracted. Premature loss of maxillary primary molars resulted in a significant acceleration of the emergence of the premolars; this was not observed in the mandible. In conclusion, when considering permanent tooth emergence ages, caries experience in the primary dentition should be taken into account.     

Shoulder complaints after neck dissection; is the spinal accessory nerve involved?

The purpose of the current study was to investigate the relation between shoulder morbidity (pain and range of motion), and the function of the spinal accessory nerve after neck dissection. Identifying dysfunction of the nerve gives insight in the mechanisms of post-operative shoulder complaints. In total 112 patients after neck dissection (73 males/39 females), mean (SD) age 61 (13) years, participated in the study. The mean duration of follow up was 3 (2) years. Five patients had radical, 43 modified radical, 48 supraomohyoid, and 16 posterolateral neck dissection. Thirty-nine complained of shoulder pain of whom 20 (51%) had dysfunction of the spinal accessory nerve, and 19 (49%) did not. In total 29 patients (26%) had dysfunction of the spinal accessory nerve of whom 20 (69%) had shoulder pain. Shoulder pain was significantly related to dysfunction of the nerve (P < 0.001). Twenty-three patients had a difference in active range of motion in shoulder abduction of > or =40 degrees, of whom 22 (96%) had dysfunction of the nerve. A difference in active shoulder abduction of > or =40 degrees was significantly related to loss of function of the spinal accessory nerve (P < 0.001). CONCLUSION: Shoulder pain after neck dissection can only be attributed to dysfunction of the spinal accessory nerve in about 50%. If patients experience shoulder pain after neck dissection examination of the trapezius muscle and active bilateral abduction of the shoulder should be made to find out if the spinal accessory nerve is involved.     

Is juxta-apical radiolucency a reliable risk factor for injury to the inferior alveolar nerve during removal of lower third molars?

The aim of this study was to find out if juxta-apical radiolucency (JAR) is a reliable risk factor for injury to the inferior alveolar nerve (IAN) during removal of lower third molars. We designed a cohort study of patients whose dental panoramic tomograms (DPT) had shown JAR before complete removal of lower wisdom teeth. The outcome variable was postoperative permanent neurosensory disturbance of the IAN. A total of 39 patients (50 lower third molars) were identified and screened for permanent neurosensory disturbance. None reported any permanently altered sensation 18 months after the operation. Based on our group, the presence of JAR does not seem to be a reliable predictor of the risk of permanent injury to the IAN during removal of lower third molars.     

Influence of the site of origin on the outcome of squamous cell carcinoma of the maxilla—oral versus sinus

The maxilla may be affected by squamous cell carcinoma (SCC) from both oral and sinus sites. We sought to determine whether the site of origin of the maxillary tumour, oral as compared to sinus, influences survival. Univariate Kaplan–Meier and multivariate Cox proportional hazard models analysis of 58 patients with SCC involving the maxilla, treated with curative intent, was conducted. The overall 5-year disease-free survival for the group was 41.7%. Five-year disease-free survival for oral subsite SCC was 56.8%, while for sinus subsite was only 21.6%. Univariate analysis found SCC of sinus origin to be associated with a poorer prognosis, however this was not confirmed on multivariate analysis. T-stage and positive margins were found to be the only independent risk factors. For SCC of the maxilla, sinus origin of the tumour per se does not confer a poorer prognosis; however, as a result of the complex anatomy of the midface, these tumours can present at an advanced stage, while surgical control of the disease can be more difficult, especially posteriorly. Tumour size and positive margins were the determinants of a poor prognosis in this group of patients with maxillary SCC.