Longitudinal Treatment Outcomes of Microsurgical Treatment of Neurosensory Deficit after Lower Third Molar Surgery: A Prospective Case Series

Injuries of the Peripheral Mandibular Nerve, Evaluation of Interventions and Outcomes: A Systematic Review

Trigeminal nerve injuries are common and there is currently no consensus on both timing and type of intervention to achieve the best outcomes. A systematic review was performed to compare the outcomes of the many different types of therapeutic interventions for nerve injury. PubMed, EBSCO, and Cochrane Review databases were used to search for studies published from January 1, 2000 to December 31, 2019. Included studies detailed treatment of an injury to peripheral branches of the trigeminal nerve, either known transection or injury causing persistent alteration in sensation. The primary outcome was functional sensory recovery via the Medical Research Council scale. Twenty studies were included, detailing outcomes of 608 subjects undergoing intervention for 622 nerve injuries. Surgical interventions were able to achieve functional sensory recovery in approximately >80% or more of the subjects. There was heterogeneity among how procedures were performed, timing to intervention, and methods of measuring recovery. The data of this study supports the ability of surgical intervention to achieve functional sensory recovery in a significant number of subjects, and found evidence for better outcomes with intervention closer to the time of injury.

Mandibular canal versus inferior alveolar canal: A Delphi study

The general principles of anatomical terminology indicate that the "mandibular canal" should be named the "inferior alveolar canal" as it accommodates the inferior alveolar neurovascular bundles. Therefore, we performed a Delphi study to evaluate the current understanding and use of the terminology in different geographical regions and areas of expertise and to determine the appropriate terminology for this bony canal. A Delphi panel was formed and questions sent and answered via email about: field of expertise (anatomy, oral surgery/oral and maxillofacial (OMF) surgery, oral radiology/OMF radiology, plastic surgery, ENT surgery, or dentistry with the exception of oral/OMF surgery and oral/OMF radiology), years of experience in the field of expertise, country currently working in, "what is the name of the bony canal that contains the inferior alveolar neurovascular bundle," and "what should the structure above be called, in general?" A total of 52 participants responded to the questionnaire. Half or more of the experts in anatomy, oral/OMF surgery, and ENT/plastic surgery considered "mandibular canal" to be the most appropriate name for this bony canal. In contrast, more than half of all experts in oral/OMF radiology and dentistry, that is, most fields of dentistry, considered "either mandibular canal or inferior alveolar canal" to be the appropriate name. The results of the Delphi study and general principles suggest that an alternative term for the "mandibular canal" should be "inferior alveolar canal."

Assessment of postoperative discomfort and nerve injuries after surgical removal of mandibular third molar: A prospective study

Introduction:

The surgical removal of mandibular third molar (M3) teeth may result in a number of complications including pain, swelling, bleeding, alveolar osteitis or nerve dysfunction. Most of these problems are temporary, but in some cases, nerve paresthesia may become permanent and lead to functional problems.

Aims and Objectives:

This study aims at measuring the clinical severity of pain, swelling, muscle trismus, infection, dry socket and any nerve injury-related paresthesia after surgical removal of M3. It also assesses the validity of the postoperative symptom severity and identifies the most frequent occurrences and postoperative complications.

Material and Methods:

The prospective study data was collected from 163 patients visiting the Department of Oral and Maxillofacial Surgery, for surgical extraction of impacted M3. Postoperative assessment was done after 1 week at the time of suture removal for pain, swelling, wound closure, postoperative bleeding, dry socket, infection, paresthesia and trismus. Pain intensity in the form of visual analogue scale, clinical swelling determination using thread measure, trismus assessment by differences in mouth opening, paresthesia/anesthesia by questioning about tongue, chin and lip sensibility and performing neurosensory tests like 2-point discrimination, pin prick and light touch. Patients with neurosensory disturbance were followed for 6 months.

Results:

This study confirmed the previously reported prevalence rates of neurological deficit and demonstrated 2% incidence of lingual nerve injury where no symptom lasted for more than 12 weeks. Inferior alveolar nerve paresthesia not reported in case series. Most of the patients reported with mild pain, mild swelling and trismus at seventh postoperative day at the time of suture removal.

Conclusion:

Although third molar surgery is a secure and low morbidity procedure, the risk of complications will always exist and it increases with increased surgical difficulty, hence the patient should always be educated about the risks and benefits of surgery in order to ensure adequate surgical management of impacted M3.

Longitudinal recovery pattern of neurosensory deficit after Le Fort I osteotomy

The purpose of this study was to investigate the incidence and recovery pattern of neurosensory deficit (NSD) following Le Fort I osteotomy, and to identify the possible risk factors that might contribute to the complication. A prospective longitudinal observational study on the incidence of NSD was conducted on patients who received Le Fort I osteotomy. Subjective and objective standardized neurosensory assessments were performed preoperatively as the baseline, and postoperatively at 2 weeks, 6 weeks, 3 months, 6 months, 12 months, and 24 months. Possible risk factors for NSD including patient age and sex, surgeon experience, and Le Fort I osteotomy with or without multi-segmentation were analysed. Sixty-six patients (43 female, 23 male) with 132 sides of Le Fort I osteotomy were recruited. The incidence of NSD at 2 weeks, 6 weeks, 3 months, 6 months, 12 months, and 24 months was 81.8%, 59.8%, 39.4%, 19.7%, 7.6%, and 3.2%, respectively. Subjective severity of NSD improved with time. Older age was found to be a risk factor for NSD in the early postoperative period, but there was no difference in the long-term. Patient sex, surgeon experience, and the need for multi-segmentation were not found to be related to the incidence of NSD after Le Fort I osteotomy.

Surgical morbidities of sagittal split ramus osteotomy versus intraoral vertical ramus osteotomy for the correction of mandibular prognathism: a randomized clinical trial

The sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) are two common orthognathic procedures for the treatment of mandibular prognathism. This randomized clinical trial compared the surgical morbidities between SSRO and IVRO for patients with mandibular prognathism over the first 2 years postoperative. Ninety-eight patients (40 male, 58 female) with a mean age of 24.4±3.5 years underwent bilateral SSRO (98 sides) or IVRO (98 sides) as part or all of their orthognathic surgery. IVRO presented less short-term and long-term surgical morbidity in general. The SSRO group had a greater incidence of inferior alveolar nerve deficit at all follow-up time points (P< 0.01). There was more TMJ pain at 6 weeks (P= 0.047) and 3 months (P= 0.001) postoperative in the SSRO group. The SSRO group also presented more minor complications, which were related to titanium plate exposure and infection. There were no major complications for either technique in this study. Despite the need for intermaxillary fixation, IVRO appears to be associated with less surgical morbidity than SSRO when performed as a mandibular setback procedure to treat mandibular prognathism.

Clinical outcomes of lingual nerve repair

Lingual nerve injury, a well-described complication of third molar removal, may result in permanent lingual sensory deficit leading to symptoms including lost or altered sensation, inadvertent tongue biting, and the development of unpleasant neuropathic pain, with consequent impaired quality of life. We analysed outcomes of a prospective case series to determine whether direct anastomosis of the lingual nerve results in improved sensory recovery and reduced neuropathic pain, and whether delayed surgery is worthwhile. In 114 patients who underwent nerve repair at our nerve injury clinic following damage sustained during mandibular third molar removal, sensory deficit was assessed before and after surgery using a questionnaire and visual analogue scales (VAS) to assess pain, tingling, and discomfort. Neurosensory tests were utilised to evaluate light touch, pin-prick, and two-point discrimination thresholds. Subjectively, 94% patients felt their sensation had improved following nerve repair, with significant reductions in the incidence of tongue biting (p<0.0001), impaired speech (p<0.0001), and neuropathic pain (p=0.0017). Quantitative neurosensory data showed highly significant improvements in light touch, pin-prick, and two-point discrimination (all p<0.0001), and VAS scores for pain (p=0.0145), tingling (p<0.0025), and discomfort (p<0.0001) were significantly reduced. Patients with high levels of pain preoperatively (VAS>40) showed highly significant reductions in pain (p<0.0001). No correlation was found between surgical outcome and patient's age or delay until surgery. Lingual nerve repair results in good sensory outcomes and significant improvements in the incidence and degree of neuropathic pain, even when delayed.

Taste disorder's management: a systematic review

BACKGROUND

Taste disorder is a frequent drug-induced or disease-related oral trouble. Various pharmacological, surgical, or physical treatments have previously been proposed for taste function recovery.

OBJECTIVES

The aim of the present systematic review was to assess the effects of palliative and curative interventions on taste recovery in light of recent literature.

MATERIALS AND METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, a search of the literature published up to June 2019 was conducted using MEDLINE via PubMed, EMBASE, and The US National Institutes of Health Trials Register (PROSPERO registration reference: CRD 42019139315). The methodological quality of the included trials was rated with the "Delphi list For Quality Assessment of Randomized Clinical Trials" and the Newcastle-Ottawa scale.

RESULTS

From the 1842 titles first identified, 28 articles met the inclusion criteria. Interventions included zinc (aspartate, sulfate, gluconate, acetate, picolinate, and Polaprezinc®), esomeprazole, L-thyroxin, bethanechol, oral glutamine, delta-9-tetrahydrocannabinol, alpha-lipoic acid, Ginkgo biloba, artificial saliva, pilocarpine, local anesthesia, and improved oral hygiene. The quality of evidence ranged from poor to high.

CONCLUSION

Improving oral hygiene may promote taste ability. Zinc may prevent and alleviate taste disorder in patients undergoing head and neck radiotherapy.

CLINICAL RELEVANCE

The systematic review provided evidence about the clinical efficacy of oral procedures, zinc supplementation, and palliative cares in dysgeusic patients. Further research is needed to find effective treatments with low adverse effects.

Management and prevention of third molar surgery-related trigeminal nerve injury: time for a rethink

Trigeminal nerve injury as a consequence of lower third molar surgery is a notorious complication and may affect the patient in long term. Inferior alveolar nerve (IAN) and lingual nerve (LN) injury result in different degree of neurosensory deficit and also other neurological symptoms. The long term effects may include persistent sensory loss, chronic pain and depression. It is crucial to understand the pathophysiology of the nerve injury from lower third molar surgery. Surgery remains the most promising treatment in moderate-to-severe nerve injuries. There are limitations in the current treatment methods and full recovery is not commonly achievable. It is better to prevent nerve injury than to treat with unpredictable results. Coronectomy has been proved to be effective in reducing IAN injury and carries minimal long-term morbidity. New technologies, like the roles of erythropoietin and stem cell therapy, are being investigated for neuroprotection and neural regeneration. Breakthroughs in basic and translational research are required to improve the clinical outcomes of the current treatment modalities of third molar surgery-related nerve injury.

Comparison of Subjective and Objective Assessments of Neurosensory Function after Lingual Nerve Repair

OBJECTIVE

Mandibular third molar extractions are important in oral maxillofacial surgery. Damage to the lingual nerves, although rare, is a possible complication. There are reports of postoperative recovery after lingual nerve repair, but few reports have compared subjective and objective assessments of neurosensory function. Therefore, this study aims to compare subjective and objective assessments of neurosensory function after lingual nerve repair.

SUBJECTS AND METHODS

This retrospective cohort study comprised 52 patients with lingual nerve anesthesia after third molar extraction at the Department of Oral and Maxillofacial Surgery, Wakayama Medical University Hospital, Wakayama, Japan, between December 2008 and December 2015. We recorded pre- and postoperative (6 months and 12 months) neurosensory examinations.

RESULTS

Patient's subjective assessments of neurosensory function suggested improvement between the preoperative period and 12 months postoperation, although this difference was not significant. Objective assessment based on examination and testing, on the other hand, showed a significant difference in improvement (p < 0.05).

CONCLUSIONS

There was no evidence that improvement of subjective preoperative and postoperative assessments was significantly associated with improvement of objective neurosensory assessments after lingual nerve repair. Overall physical condition and background were thought to affect subjective evaluation. Subjective assessment is important in conjunction with objective evaluation because it may reveal dysesthesia that would otherwise be missed. In the future, we will examine those cases in whom subjective assessments showed no improvement although objective assessments showed improvement.