Evaluating Lingual Nerve Repair Outcomes: A Systematic Review.

PURPOSE: The lingual nerve (LN) is susceptible to injury during oral and maxillofacial procedures, leading to neurosensory deficits. Advances in microsurgical techniques necessitate a comprehensive review of overall effectiveness and influencing factors. METHODS: A systematic review was performed via Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify studies. Inclusion criteria were full text availability, studies written in english, and studies published after 2000 reporting LN repair. The primary outcome was sensory improvement defined via functional sensory recovery (FSR) or neurosensory testing (NST). Sex, time from injury to repair, method of repair, and graft length were examined to see if each influenced outcomes. RESULTS: A sample of 786 subjects across 17 studies was examined. Most patients were female (73.3%) and suffered injuries from third molar extractions (72.8%). Of the studies, 10 defined improvement by FSR with a total of 88.8% (500/563) of nerves achieving such. Of those achieving FSR, 91% did so within a year. The remaining 7 studies defined sensory improvement by individually setting various NST thresholds, with the combined improvement rate being 88.6% (203/229). Positive outcomes were achieved with graft lengths up to 70 mm. Results on time to repair were mixed. The methods of repairs were not different based on statistical analysis short of performing an equivalence trial. CONCLUSION: Conclusions made from studies using FSR were similar to studies using NST, meaning the method of measuring outcomes does not seem to be a confounder. FSR is the superior scale due to being objective and standardized. LN repair produced high rates of sensory improvement, which is expected to occur within 1 year postoperative. Sex and graft length did not influence outcomes. More research is needed to determine the effect of time to repair on efficacy. Most methods of repair produced similar outcomes, suggesting multiple valid techniques exist.

Surgical anatomy of the lingual nerve for palate surgery: where is located and how to avoid it.

PURPOSE: To describe the anatomic relationship of the lingual nerve with the lateral oropharyngeal structures. METHODS: An anatomic dissection of the lateral oropharyngeal wall was conducted in eight sides from four fresh-frozen cadaveric heads. Small titanium clips were placed along the lingual nerve and the most anterior and medial border of the medial pterygoid muscle. Radiological reconstructions were employed for optimal visualization; the coronal view was preferred to resemble the surgical position. The distance between the lingual nerve and the medial pterygoid muscle at its upper and lower portion was measured radiologically. The trajectory angle of the lingual nerve with respect to the pterygomandibular raphe was obtained from the intersection between the vector generated between the clips connecting the upper and lower portion of the medial pterygoid muscle with the vector generated from the lingual nerve clips. RESULTS: The mean distance from the upper portion of the medial pterygoid muscle and superior lingual nerve clips was 10.16 ± 2.18 mm (mean ± standard deviation), and the lower area of the medial pterygoid muscle to the lingual nerve was separated 5.05 ± 1.49 mm. The trajectory angle of the lingual nerve concerning to the vector that describes the upper portion of the most anterior and medial border of the medial pterygoid muscle with its lower part was 43.73º ± 11.29. CONCLUSIONS: The lingual nerve runs lateral to the lateral oropharyngeal wall, from superiorly-inferiorly and laterally-medially, and it is closer to it at its lower third.

Anatomical Relationship Between the Lingual Nerve and Submandibular Duct.

ABSTRACT: The purpose of this study was to investigate the anatomical relationship between the lingual nerve and submandibular duct. This study included 1403 patients with submandibular or sublingual gland diseases who underwent intraoral removal of submandibular gland sialoliths, submandibular glands, or sublingual glands. Of all patients, 33 patients underwent bilateral surgeries. All surgeries were performed a single surgeon, and the anatomical relationship between the lingual nerve and submandibular duct was always identified intraoperatively and recorded in the operation recorded. The anatomical relationship was investigated based on the intraoperative findings. The lingual nerve which crosses above the submandibular duct was detected in 8 of 1436 sides (0.6%). There were 4 in the right sides and 4 in the left sides. The lingual nerve below the submandibular gland was seen in 99.4%. Although the lingual nerve crosses above the submandibular duct with a rarer incidence, surgeons should beware of injuring the lingual nerve during intraoral salivary gland surgery.

An Atypical Path of the Lingual Nerve in the Retromolar Region: Incidence in Oral Surgery.

The Lingual nerve is frequently anesthetized during oral, maxillofacial, or otorhinolaryngology surgery. It originates below the oval hole in the infratemporal region, follows its path down and forward, and moves away from the medial surface of the ramus. From there, it goes just above the mylohyoid line. It approaches the lateral margin of the tongue and crosses the Wharton's canal, and divides into numerous branches. Some cases of temporomandibular joint syndrome or myofascial pain syndrome could be a result of its anatomical variations. Also, the jurisprudence has always condemned the practitioner if for not demonstrating that the path of the injured nerve presents an anomaly which makes his involvement inevitable. The purpose is to present one of the multiple atypical paths of the lingual nerve not described in the retromandibular trigone, demonstrating that its damage constitutes a risk that cannot be controlled.

Outcomes of Direct Lingual Nerve Repair After an Injury: A Systematic Review.

PURPOSE: The purpose of this study was to conduct a systematic review with meta-analysis to investigate the outcomes of direct lingual nerve repair after injury. MATERIALS AND METHODS: The studies in this review were compiled by using PubMed/Medline and ScienceDirect, which were searched by a single reviewer (M.K.) from their inception until March 10, 2020. Two independent reviewers (M.K. and V.B.Z.) who were blinded to each other's assessments reviewed full-text articles to assess for study inclusion. Outcomes were dichotomized as either functional sensory recovery (FSR) or no FSR. Clinical testing must have been assessed at a minimum of 6 months postoperatively. FSR was defined as grade S3, S3+, or S4 on the British Medical Research Council scale of neurosensory function. Studies were only eligible if they provided the number of patients treated with conduits or time from injury to repair and the associated rates of FSR with each intervention. RESULTS: The initial search using the key terms yielded 4,921 results, which was then eventually filtered down to 6 articles after multiple levels of appraisal. Five articles were retrospective cohort studies and 1 was a randomized controlled study. Four of the 6 studies reported an FSR of grade S3 or higher in 85% or more of the patients. Conduit use was not associated with a significantly greater likelihood of achieving FSR (pooled risk ratio = 1.10; 95% confidence interval, 0.96 to 1.27; P = .17). Repair within 6 months was associated with significantly improved likelihood of achieving FSR (pooled risk ratio = 0.84; 95% confidence interval, 0.71 to 0.99; P = .04). CONCLUSIONS: The use of conduits during repair was not associated with clinically significant increased FSR. Early repair was associated with a beneficial effect on FSR; however, heterogeneity was an issue with the studies. There is a lack of strong evidence owing to the nature of studies analyzed and the need for further research is required.

Solitary neurofibroma of the floor of the mouth: rare localization at lingual nerve with intraoral excision.

BACKGROUND: Neurofibromas (NF) are benign tumors of the peripheral nerves that are composed of Schwann cells, perineural-like cells and fibroblasts. The differential diagnosis for a solitary intraneural variant of neurofibroma arising in the floor of the mouth is broad and includes a submandibular gland neoplasm and adenopathy, among others. The intraoral approach is the best choice for a medium-sized lesion. CASE PRESENTATION: We report a rare case of a solitary neurofibroma of the floor of the mouth in a 31-year-old male. The patient consulted the dental emergency department for acute pain of the left mandible. Systematic clinical examination revealed the presence of a mass in the left mouth floor. The panoramic x-ray was not conclusive and the magnetic resonance imaging (MRI) revealed a well-defined soft tissue lesion with homogenous isosignal intensity on the T1-weighted image, high intensity signal on the T2-weighted image and heterogeneous enhancement following contrast-enhancement on the T1-weighted Fast Sat image. The surgical excision of the soft-tissue neoplasm was accomplished by an intraoral approach. The specimen was sent for histopathologic analysis and Immunohistochemical studies which confirmed the diagnosis of a myxoid predominant intraneural solitary neurofibroma. CONCLUSION: The diagnosis of neurofibroma was confirmed by histopathological evaluation and immunohistochemical studies which also excluded other entities in the histopathologic differential diagnosis including schwannoma and a malignant peripheral nerve sheath tumor among other. Localized (solitary) neurofibromas most often occur as sporadic lesions, however; diagnosis of a solitary neurofibroma prompts clinical evaluation to exclude the remote possibility of neurofibromatosis. The purpose of this case report is to raise awareness of the uncommon presentation of neurofibroma and to document the successful management of such a lesion using an intraoral approach.

Objective Assessment of Lingual Nerve Microsurgical Reconstruction.

Lingual nerve (LN) injury is one of the most serious consequences of oral surgery. Prompt microsurgical reconstruction of the nerve can alleviate most of those symptoms leading to satisfactory functional recovery.Thirty-five patients with partial to complete LN injury underwent surgery in the period between January 2006 and May 2015. All patients underwent a preoperative clinical and neurological evaluation with the assessment of lingual tactile and pain sensory thresholds and masseteric inhibitory reflex.All patients underwent explorative surgery and direct microneurorrhaphy of distal and proximal stumps in case of complete lesion, while the removal of traumatic neuroma and the following microneurorrhaphy of distal and proximal stumps of the injured nerve was performed in case of incomplete lesion. Nerve grafting has always been avoided because of distal stump mobilization obtained by severing the submandibular branch of the LN.All patients but 1 exhibited good recovery of tongue sensation, never complete, both clinically and electrophysiologically: recovery of the excitability of masseteric inhibitory reflex suppression components SP1 and SP2 was observed, often with increased latencies but consistent with a functional recovery.All patients feeling pain preoperatively experienced complete relief of algic symptoms.The early microsurgical approach is the most suitable choice for the treatment of LN injuries.

Neuropathic Pain Due to Iatrogenic Lingual Nerve Lesion: Nerve Grafting to Reduce Otherwise Untreatable Pain.

Iatrogenic lingual nerve lesion is a well-known and unfortunate complication after mandibular third molar removal. Occasionally, the nerve injury can cause severe neuropathic pain.Here, the authors present the history of 2 patients with lingual nerve injury due to mandibular third molar removal, and with severe neuropathic pain in the craniomandibular region. Pharmacotherapy and physiotherapy did not reduce the pain, and ultimately, the lingual nerve was surgically explored. Scar tissue and a lingual nerve neuroma were observed and resected in both patients.In the first patient, the gap between the nerve stumps was bridged with an autologous sural nerve graft. In the second patient, some continuity of the lingual nerve was preserved and the resected part was substituted with an autologous sural nerve graft. Significant pain reduction was achieved in both patients and no further medical treatment was necessary at the end of follow-up.These reports show that lingual nerve reconstruction can be a successful therapy in patients experiencing severe neuropathic pain after iatrogenic lingual nerve injury. Different treatment options for neuropathic pain due to lingual nerve injury are discussed.

The clinical view for dissection of the lingual nerve with application to minimizing iatrogenic injury.

The importance of the position of the lingual nerve in the oral cavity cannot be understated for dentists and oral surgeons. Therefore, the location of the lingual nerve with various positions of the tongue is important. However, most dental and medical students are taught oral cadaveric anatomy where tissues are fixed. Therefore, the focus of this article is to demonstrate how the lingual nerve moves based on tongue movement in fresh tissues and how this is important for dentists and oral surgeons. Clin. Anat. 30:467-469, 2017. © 2017 Wiley Periodicals, Inc.

Nerve Sharing Between the Lingual and Mental Nerve to Restore Lower Lip Sensation After Segmental Resection of the Mandible.

This report demonstrates a successful new procedure for reconstructing the inferior alveolar nerve by transplanting the great auricular nerve (GAN) between the mental nerve and the remaining submandibular ganglion to achieve nerve sharing of the lingual nerve. A 59-year-old woman with discomfort in the left mandibular retromolar region and ipsilateral neck was referred to our hospital by a local dentist. Physical examination showed mild swelling and redness at the left mandibular retromolar region. The histologic diagnosis showed central mucoepidermoid carcinoma of the jaw. With the patient under general anesthesia, segmental resection of the mandible followed by level 1 selective neck dissection was performed. The resected mandible was reconstructed with a titanium plate. The submandibular incision was extended to the lower edge of the tragus for harvesting of the GAN. The GAN was grafted, and an epineural neurorrhaphy was carried out with the mental nerve, as well as the submandibular ganglion, under a microscope. After the operation, submental sensation was evaluated with a Semmes-Weinstein pressure esthesiometer. The Semmes-Weinstein pressure esthesiometer test showed a loss of perception at the third week after surgery. Within 12 months, nerve sensation was substantially improved and the patient was free from discomfort.

Lingual Nerve Repair: To Graft or Not to Graft?

PURPOSE: Since no studies have compared direct and graft repair of the lingual nerve, we examined the subjective and objective outcomes of lingual nerve repair by direct epineurial repair and indirect graft repair, assessed the effect of other confounding variables, and compared the outcomes of autograft and allograft repairs. PATIENTS AND METHODS: All patients who had undergone microneurosurgical repair of the lingual nerve from 2000 to 2012 by 1 surgeon (M.M.) were asked to complete an online questionnaire regarding their current neurosensory status at least 2 years after nerve repair. A direct comparison was made between patients who had undergone direct epineurial repair and those who had undergone interpositional nerve graft repair. Student's t test and χ(2) test were used to determine whether a significant difference existed in the success between the 2 techniques and whether age, gender, race, delay from injury to repair, or degree of initial nerve deficit influenced the success of nerve repair. RESULTS: Of the 72 patients identified, 43, who had undergone 47 nerve repairs (18 direct, 29 indirect graft repairs [4 bilateral]; 28 female and 19 male patients; mean age 28.3 years), were interviewed. The objective results of functional sensory recovery, defined by a Medical Research Council Scale grade of S3, S3+, or S4, was 89% for the graft repairs and 85% for the direct repairs (P = .01). The subjective patient satisfaction score (0 to 10 scale) was 8.9 for the graft repairs and 8.1 for the direct repairs (P = .02). The autograft and allograft repairs performed comparably, and the other variables (ie, age, gender, race, delay from injury to nerve repair, gap length, and initial Sunderland grade injury) were not found to be significant (P > .05). CONCLUSION: Graft repair of the lingual nerve provides superior long-term (>2 years) objective and subjective outcomes compared with direct repair. This might be because of the lack of tension at the repair site, more freedom with nerve stump preparation, and the addition of neurotropic and neurotrophic factors from the donor nerve graft at the site of injury to augment neurosensory recovery.

Sensory outcomes after reconstruction of lingual and inferior alveolar nerve discontinuities using processed nerve allograft--a case series.

PURPOSE: The present study describes the results of using a processed nerve allograft, Avance Nerve Graft, as an extracellular matrix scaffold for the reconstruction of lingual nerve (LN) and inferior alveolar nerve (IAN) discontinuities. PATIENTS AND METHODS: A retrospective analysis of the neurosensory outcomes for 26 subjects with 28 LN and IAN discontinuities reconstructed with a processed nerve allograft was conducted to determine the treatment effectiveness and safety. Sensory assessments were conducted preoperatively and 3, 6, and 12 months after surgical reconstruction. The outcomes population, those with at least 6 months of postoperative follow-up, included 21 subjects with 23 nerve defects. The neurosensory assessments included brush stroke directional sensation, static 2-point discrimination, contact detection, pressure pain threshold, and pressure pain tolerance. Using the clinical neurosensory testing scale, sensory impairment scores were assigned preoperatively and at each follow-up appointment. Improvement was defined as a score of normal, mild, or moderate. RESULTS: The neurosensory outcomes from LNs and IANs that had been microsurgically repaired with a processed nerve allograft were promising. Of those with nerve discontinuities treated, 87% had improved neurosensory scores with no reported adverse experiences. Similar levels of improvement, 87% for the LNs and 88% for the IANs, were achieved for both nerve types. Also, 100% sensory improvement was achieved in injuries repaired within 90 days of the injury compared with 77% sensory improvement in injuries repaired after 90 days. CONCLUSIONS: These results suggest that processed nerve allografts are an acceptable treatment option for reconstructing trigeminal nerve discontinuities. Additional studies will focus on reviewing the outcomes of additional cases.

Transoral submandibular ganglion neurectomy: an anatomical feasibility study.

BACKGROUND: The management of sialorrhea can be difficult for both the patient and the clinician. Current management includes behavioral modification, anticholinergics, botulinum injections, and a variety of surgical options, which all have demonstrated some efficacy. As minimally invasive procedures flourish, we explore the feasibility of highly selective transoral submandibular neurectomy (TOSN) for the management of sialorrhea. METHODS: Ten human cadaver dissections of the floor of mouth were performed bilaterally, for a total of 20 separate cases. An intraoral technique for highly selective, submandibular ganglion neurectomy is demonstrated. RESULTS: A transoral submandibular ganglion neurectomy was performed in 10 cadavers (20 neurectomies) easily and reliably, without injury to the submandibular duct or the main trunk of the lingual nerve. CONCLUSION: Transoral submandibular neurectomy is an attractive addition to the armamentarium of surgical options for the treatment of medically intractable sialorrhea. Further study in selected patients would need to be performed to demonstrate clinical feasibility.

Evidence-based outcomes following inferior alveolar and lingual nerve injury and repair: a systematic review.

The inferior alveolar nerve (IAN) and lingual (LN) are susceptible to iatrogenic surgical damage. Systematically review recent clinical evidence regarding IAN/LN repair methods and to develop updated guidelines for managing injury. Recent publications on IAN/LN microsurgical repair from Medline, Embase and Cochrane Library databases were screened by title/abstract. Main texts were appraised for exclusion criteria: no treatment performed or results provided, poor/lacking procedural description, cohort <3 patients. Of 366 retrieved papers, 27 were suitable for final analysis. Treatment type for injured IANs/LNs depended on injury type, injury timing, neurosensory disturbances and intra-operative findings. Best functional nerve recovery occurred after direct apposition and suturing if nerve ending gaps were <10 mm; larger gaps required nerve grafting (sural/greater auricular nerve). Timing of microneurosurgical repair after injury remains debated. Most authors recommend surgery when neurosensory deficit shows no improvement 90 days post-diagnosis. Nerve transection diagnosed intra-operatively should be repaired in situ; minor nerve injury repair can be delayed. No consensus exists regarding optimal methods and timing for IAN/LN repair. We suggest a schematic guideline for treating IAN/LN injury, based on the most current evidence. We acknowledge that additional RCTs are required to provide definitive confirmation of optimal treatment approaches.

Outcome following lingual nerve repair with vein graft cuff: a preliminary report.

PURPOSE: The object of this study was to assess the effects of an inside-out vein graft as a cuff after direct suture on human lingual nerve regeneration and recovery after iatrogenic lingual nerve injury. PATIENTS AND METHODS: Ten patients with unilateral lingual nerve anesthesia as a complication of iatrogenic injury after third molar extraction underwent microneurosurgical procedures for the injured lingual nerve under general anesthesia. The patients were randomized into 2 groups. In group A, after removing the neuromas and peripheral scars surrounding the torn nerves, the 2 nerve ends were sutured without tension. In group B, after the same procedure, including the same suturing procedure, an inside-out vein graft was placed as a cuff after the direct suture. Each group was followed at least once every 6 months for 1 year after the procedure. Postoperative outcomes were evaluated using the Pogrel criteria, the Sunderland grade, and the British Medical Research Council Scale (MRCS). RESULTS: There were no particular differences between groups A and B at 6 and 12 months after the operation. However, based on the MRCS criteria, there was a clearly better result in group B than in group A at 6 and 12 months after the operation, and the recovery of gustatory sensation tended to be better in group B than in group A 1 year after the operation. CONCLUSION: This inside-out vein graft as a cuff after direct suturing may facilitate faster lingual nerve regeneration than the traditional direct suture approach. The inside-out vein graft as a cuff may provide the advantages of preventing axonal escape at the suture lines, minimizing nerve entrapment, and preventing neuroma formation in the space between the sutured nerves.

Risk factors for permanent injury of inferior alveolar and lingual nerves during third molar surgery.

PURPOSE: The purpose of this study was to assess the incidence of and risk factors for permanent neurologic injuries to the inferior alveolar nerve (IAN) or lingual nerve (LN) after the removal of third molars. This report also describes the use of a Clinical Incident Review (CIR) process, allowing close monitoring of all patients with neurologic injuries as a result of dentoalveolar surgery. MATERIALS AND METHODS: A database associated with a CIR process at the Royal Dental Hospital of Melbourne from January 2006 through December 2009 was assessed. Factors assessed included gender, age, operator class, method of anesthesia, spacial relation, depth of impaction, ramus relation, proximity of the IAN on orthopantomogram, cone-beam computed tomographic usage, and side of injury. RESULTS: During this 4-year period, 11,599 lower third molars were removed in 6,803 patients. The incidence of an IAN injury was 0.68%, and the incidence of an LN injury was 0.15%. Important risk factors for permanent IAN injury were increasing age, surgery performed by staff dentists, type of anesthesia, and mesioangular impactions. The mean time of complete resolution was 4.3 months. No factors were found to statistically increase the risk of LN injury, although most injuries were seen in patients with a distoangular impaction. CONCLUSION: The overall incidences of IAN and LN injuries were low. Some risk factors for permanent IAN nerve injury were identified. Important risk factors for permanent IAN injury were increasing age (≥25 yr old), surgery performed by staff dentists, surgery under general anesthesia, and mesioangular impaction. No factors were found to statistically increase the risk of LN injury.

The relationship between lingual and hypoglossal nerve function and quality of life in head and neck cancer.

Sensorimotor impairment of the tongue has the potential to affect speech and swallowing. The purpose of this study was to critically examine the effects of nerve preservation and reinnervation after reconstruction of the base of tongue on patient-perceived outcomes of quality of life (QoL) related to speech and swallowing through completion of the EORTC QLQ-H&N35 standardised questionnaire. Thirty participants with a diagnosis of base of tongue cancer underwent primary resection and reconstruction with a radial forearm free flap, which may or may not have included nerve repair to the lingual nerve, hypoglossal nerve or both. Eight QoL domains sensitive to changes in motor and sensory nerve function were included in the analysis. Transected lingual and hypoglossal nerves were associated with difficulty in swallowing, social eating, dry mouth and social contact. There were fewer problems reported when these nerves were either repaired or left intact. There were no significant differences between patient nerve status and QoL outcomes for speech, sticky saliva and use of feeding tubes. This study was the first to examine the impact of sensory or motor nerve transection and reconstruction on health-related QoL outcomes.

Interval between injury and lingual nerve repair as a prognostic factor for success using type I collagen conduit.

PURPOSE: The purpose of the present study was to investigate the role of a type I collagen nerve conduit in the repair of lingual nerve injuries compared with those lingual nerve repairs performed without a collagen membrane and to identify the prognostic factors for functional sensory recovery (FSR). MATERIALS AND METHODS: This was a retrospective cohort study evaluating a sample derived from the population of patients who had undergone lingual nerve microsurgery from March 17, 2000, to February 23, 2010 by the same surgeon (V.B.Z.) with complete records available, including follow-up assessments. The primary outcome variable was the interval to successful FSR according to the British Medical Research Council criteria for FSR. The predictor variables were categorized into demographic, surgical, and clinical sensory testing. Appropriate descriptive statistics and univariate and multivariate Cox proportional hazards survival statistics were computed in analyzing the patient age at lingual nerve injury repair (in years), gender, timing of surgical intervention, mechanism of injury, specific surgical procedures, and application of a type I collagen conduit. RESULTS: The study cohort included 41 patients with 42 lingual nerve injuries who underwent surgical repair. Their mean age was 28.3 ± 8.3 years (range 13 to 44), with 88% females (n = 32). In the multivariate model, the injury to surgery interval per 1-month increase (hazard ratio 1.23, 95% confidence interval 1.02 to 1.48, P = .029) and injury to surgery interval of 9 months or longer (hazard ratio 4.67, 95% confidence interval 1.04 to 20.87, P = .04) remained significantly associated statistically with successful FSR. CONCLUSIONS: The results of the present study have demonstrated that the injury to surgery interval is the most significant prognostic factor in the repair of lingual nerve injuries. The use of the collagen membrane demonstrated a greater level of FSR compared with those treated without the use of the membrane. However, the results from the collagen conduit were not statistically significant.

Treatment of recurrent lingual nerve end-neuroma: A case report.

A neuroma is a collection of disorganized nerve sprouts emanating from an interruption of axonal continuity, forming within a collagen scar as the nerve attempts to regenerate. Lingual neuroma formation secondary to iatrogenic trauma to the tongue is likely not uncommon; however, we could not find a report in the literature of treatment of a distal tongue end-neuroma treated by resection and implantation into muscle. Here we describe a patient who experienced debilitating chronic tongue pain after excision of a benign mass. After failing conservative management, the patient was taken to the operating room where an end-neuroma of the lingual nerve was identified and successfully treated by excision and burying of the free proximal stump in the mylohyoid muscle. At 17 months postoperatively, she remains pain free without dysesthesias.

Lingual nerve impairment/injury after retrieval of the displaced mandibular third molar into the floor of the mouth.

Retrieval of the displaced mandibular third molar in the floor of the mouth is challenging as the lingual nerve is always at risk of injury. However, there are no available data to show the incidence of the injury caused by the retrieval. The goal of this review article is to provide the incidence of the iatrogenic lingual nerve impairment/injury caused by the retrieval based on the review of the existing literature. The retrieval cases were collected with the search words below using PubMed, Google Scholar, and CENTRAL Cochrane Library database on October 6, 2021. A total of 38 cases of lingual nerve impairment/injury in 25 studies were eligible and reviewed. Temporary lingual nerve impairment/injury due to retrieval was found in six cases (15.8%) and all recovered between three to six months after retrieval. General anaesthesia and local anaesthesia were used for retrieval in three cases each. The tooth was retrieved using a lingual mucoperiosteal flap in all six cases. The permanent iatrogenic lingual nerve impairment/injury due to retrieval of the displaced mandibular third molar is considered extremely rare as long as the appropriate surgical approach is chosen based on surgeons' clinical experience and anatomical knowledge.