Assessing the Efficacy of Allogeneic Nerve Grafts in Trigeminal Nerve Repair: A Systematic Review.

PURPOSE: Our primary objective was to assess the efficacy of allogeneic nerve grafts in inferior alveolar nerve or lingual nerve repair. We hypothesized that using allogeneic nerve grafts would be effective, as evidenced by achieving high rates of functional sensory recovery (FSR). Additionally, we looked if sex, time from injury to repair, etiology of nerve damage, and graft length affected outcomes. METHODS: A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. PubMed and Scopus databases were searched using specific search strategies to generate eligible studies. Inclusion criteria encompassed studies reporting use of allogeneic grafts, assessing FSR using either Medical Research Council Scale or Neurosensory Testing, and published within the past 15 years. RESULTS: Across 10 studies conducted between 2011 and 2023, analysis was performed on 149 patients and 151 reconstructed nerves. Allogeneic nerve grafts showed an average FSR rate of 88.0%. Kaplan-Meier analysis of time to FSR postoperatively revealed that of those achieving FSR, 80% achieved it within 6 months and 98% achieved it by 1 year. The mean graft length was 29.92 mm ± 17.94 mm. The most common etiology for nerve damage was third molar extractions (23.3%). Sex distribution among patients revealed that 85 were female (57.0%) and 64 were male (43.0%). CONCLUSION: Our primary hypothesis was supported as nerve allografts achieved high rates of FSR. FSR was achieved in normative timeframes, which is 6 to 12 months postoperatively. Furthermore, allografts reduced the risk of posttraumatic trigeminal neuropathy. Time from injury to repair, graft length, etiology of nerve damage, and sex did not affect FSR. As the assessed variables in our study did not affect outcomes, there needs to be a more nuanced approach to understanding and addressing various factors influencing sensory recovery.

Management of inferior alveolar nerve and lingual nerve injuries in the UK - a cross-sectional study.

Post operative nerve injury following mandibular third molar (M3M) potentially impacts a significant number of patients. A lack of consensus for the management of trigeminal nerve injuries exists. It is important to know how clinicians manage these injuries, and how confidently. A 16-question online survey using SurveyMonkey was developed and sent to all current UK members of three oral srelated societies (ABAOMS, BAOS and BAOMS) from January 2021 to March 2021. The survey consisted of open free text, binomial and variable scale responses related to the management of inferior alveolar nerve and lingual nerve injuries. A total of 158 clinicians responded to the survey. The average number of M3M removed monthly over the last three years by a clinician was 25. The average number of nerve injuries seen in a clinician's practice, within the last three years, was three. Over two-thirds of respondents were only somewhat confident, not so confident, or not at all confident in the management of patients with inferior alveolar nerve (IAN) and lingual nerve (LN) injury. In occurrence of an injury, only 45% stated they would make an onward referral and a minority of clinicians had access to surgical repair within their own unit. Free text responses highlighted themes of a lack of UK awareness of management interventions and pathways for these patients. Clear national guidance on managing trigeminal nerve injuries was a commonly desired theme from responding clinicians. Joint speciality partnerships and a national nerve repair registry is now required.

Diagnosis and Management of Lingual Nerve Injuries.

Injury to the lingual nerve is a well-recognized risk associated with certain routine dental and oral surgical procedures. The assessment and management of a patient with a traumatic lingual nerve neuropathy requires a logical and stepwise approach. The proper application and interpretation of the various neurosensory tests and maneuvers is critical to establishing an accurate diagnosis. The implementation of a surgical or nonsurgical treatment strategy is based not only on the established diagnosis, but also a multitude of variables including patient age, timing and nature of the injury, and the emotional or psychological impact.

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.

A new treatment for lingual nerve injury: an anatomical feasibility study for using a buccal nerve pedicle graft.

PURPOSE: Lingual nerve (LN) palsy is a serious complication in dentistry and repaired by direct suture or a free graft technique. To our knowledge, there has been no study using a (long) buccal nerve (BN) graft as a donor for LN repair. Therefore, we aimed to clarify the location of the BN and investigate if it is feasible to reroute the BN to the LN. METHODS: Twenty-four sides from 12 fresh-frozen Caucasian cadaveric heads were used in this study. The mean age at death was 73.9 ± 13.4 years. The LN was dissected on the floor of the oral cavity medial to the third molar tooth. Next, the mucosa with the buccinator muscle, pterygomandibular raphe, and superior pharyngeal constrictor muscle on the retromolar area was retracted anteriorly to widen the pathway of the LN. Finally, the BN was cut and transposed to the LN through this widened pathway to its feasibility. RESULTS: The mean diameter of the BN and vertical distance from the horizontal part of the retromolar trigone to the BN was 1.47 ± 0.32 mm and 18.53 ± 6.21 mm, respectively. On all sides, the BN was able to be transposed to the LN without tension. CONCLUSION: Such a technique might be used for the patients with LN injury and who have lost sensation of the tongue.

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.

Reconstructive Options for Inferior Alveolar and Lingual Nerve Injuries After Dental and Oral Surgery: An Evidence-Based Review.

PURPOSE: The investigators wanted to evaluate, analyze, and compare the current microsurgical repair modalities (primary repair, autograft, tube conduit, and allograft reconstruction) in achieving functional sensory recovery in inferior alveolar and lingual nerve reconstructions due to injury. METHODS: A literature review was undertaken to identify studies focusing on microsurgical repair of inferior alveolar and lingual nerve injuries. Included studies provided a defined sample size, the reconstruction modality, and functional sensory recovery rates. A Fischer exact test analysis was performed with groups based on the nerve and repair type, which included subgroups of specific nerve gap reconstruction modalities. RESULTS: Twelve studies were analyzed resulting in a sample consisting of 122 lingual nerve and 137 inferior alveolar nerve reconstructions. Among the nerve gap reconstructions for the lingual nerve, processed nerve allografts and autografts were found to be superior in achieving functional sensory recovery over the conduits with P values of 0.0001 and 0.0003, respectively. Among the nerve gap reconstructions for the inferior alveolar nerve, processed nerve allografts and autografts were also found to be superior in achieving functional sensory recovery over the conduits with P values of 0.027 and 0.026, respectively. Overall, nerve gap reconstructions with allografts and autografts for inferior alveolar and lingual nerve reconstruction were superior in achieving functional sensory recovery with a P value of <0.0001. CONCLUSIONS: The data analyzed in this study suggest that primary tension-free repair should be performed in inferior alveolar and lingual nerve reconstructions when possible. If a bridging material is to be used, then processed nerve allografts and autografts are both superior to conduits and noninferior to each other. In addition, allografts do not have the complications related to autograft harvesting such as permanent donor site morbidity. Based on the conclusions drawn from these data, we provide a reproducible operative technique for inferior alveolar and lingual nerve reconstruction.

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.

Lingual Nerve Microsurgery Outcomes Using 2 Different Conduits: A Retrospective Cohort Study.

PURPOSE: This study compared a type 1 collagen conduit (NeuraGen) with a porcine small intestinal submucosa conduit (AxoGuard) when used in lingual nerve microsurgery and any differences in achieving functional sensory recovery (FSR). PATIENTS AND METHODS: All patients who underwent lingual nerve microsurgery performed by 1 surgeon (V.B.Z.) from 2007 to 2014 had their surgical information obtained by a retrospective review of hospital records and office charts after institutional review board approval. Those patients whose surgery included the use of a nerve conduit were included in the study. Subjective neurosensory recovery was determined by neurosensory testing, including responses to hot, cold, wisp, brush, and pinprick. Objective recovery was determined by testing 2-point discrimination and fine touch threshold with von Frey fibers. The objective findings were correlated to a Medical Research Council System score, with grades S3, S3+, and S4 indicating FSR. RESULTS: The conduits were compared using a Student t test with a 2-tailed hypothesis. The von Frey fiber test had a preoperative mean of 6.29 (standard deviation [SD], 0.95), which improved to 3.97 (SD, 0.67) for the NeuraGen and 4.17 (SD, 0.56) for the AxoGuard. Two-point discrimination improved from a mean higher than 19.42 to 9.32 mm (SD, 2.96 mm) for the NeuraGen and 9.67 mm (SD, 2.13 mm) for the AxoGuard. The mean FSR was S3+. CONCLUSIONS: There were no meaningful differences in outcomes between the 2 conduits studied, and all patients achieved FSR according to the Medical Research Council Scale.

Prognosis After Surgical Treatment of Trigeminal Neuropathy with a PGA-c Tube: Report of 10 Cases.

OBJECTIVE: Although surgery using a polyglycolic acid-collagen (PGA-c) tube is effective for peripheral nerve injury-induced chronic hand pain, it has not been applied to trigeminal nerve lesions because of the difficult approach. We used a PGA-c tube during surgery for trigeminal neuropathy and evaluated its prognosis based on the outcomes. DESIGN: Case report. SETTING AND PATIENTS: In the dental anesthesia division of a university hospital, 11 patients with severe dysesthesia underwent surgical repair of a damaged lingual nerve (LN) or inferior alveolar nerve (IAN). One patient was lost to follow-up. Changes in quantitative sensory testing (QST) and the presence of dysesthesia as a treatment outcome were compared preoperatively and postoperatively in 10 patients. Two surgical treatments, bridging or encircling peripheral nerves, were applied. Bridging of both stumps was selected when neurotmesis was detected or the nerve was lacerated during surgery (N = 4). Otherwise, a longitudinal PGA-c tube was used to encircle the lesion (N = 6). Outcomes were evaluated 2 months to 8 years postoperatively. RESULTS: Both methods improved the patients' condition based on QST results (brush stroke perception, mechanical touch threshold, sensitivity to cold/hot stimuli). Preoperative allodynia or dysesthesia was resolved in six patients and greatly reduced in four. Two patients (one with inflammation-induced pain, one with implant-related pain) developed prolonged postoperative allodynia requiring pain-relief medication. CONCLUSIONS: Use of a PGA-c tube for surgical treatment of intractable pain due to LN or IAN neuropathy helps alleviate sensory impairment. The possibility of new dysesthesias emerging postoperatively, however, should be noted.

Use of Fibrin Glue as an Adjunct in the Repair of Lingual Nerve Injury: Case Report.

This report describes a case of lingual nerve injury repair using a novel technique in which Tisseel fibrin glue was used to stabilize an Axoguard nerve conduit placed around the site of primary neurorrhaphy to decrease the number of sutures required for stabilization. Five months postoperatively, the patient subjectively had increased sensation and improved taste in the left lingual nerve distribution. At neurosensory examination, the patient exhibited functional neurosensory recovery (S3+ on the Medical Research Council Scale).

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

OBJECTIVE: To prospectively evaluate the longitudinal subjective and objective outcomes of the microsurgical treatment of lingual nerve (LN) and inferior alveolar nerve (IAN) injury after third molar surgery. MATERIALS AND METHODS: A 1-year longitudinal observational study was conducted on patients who received LN or IAN repair after third molar surgery-induced nerve injury. Subjective assessments ("numbness", "hyperaesthesia", "pain", "taste disturbance", "speech" and "social life impact") and objective assessments (light touch threshold, two-point discrimination, pain threshold, and taste discrimination) were recorded. RESULTS: 12 patients (10 females) with 10 LN and 2 IAN repairs were recruited. The subjective outcomes at post-operative 12 months for LN and IAN repair were improved. "Pain" and "hyperaesthesia" were most drastically improved. Light touch threshold improved from 44.7 g to 1.2 g for LN repair and 2 g to 0.5 g for IAN repair. CONCLUSION: Microsurgical treatment of moderate to severe LN injury after lower third molar surgery offered significant subjective and objective sensory improvements. 100% FSR was achieved at post-operative 6 months.

The prognostic value of histopathology on lingual nerve neurosensory recovery after micro-neurosurgery.

OBJECTIVE: Micro-neurosurgical repair is considered in permanent nerve damage but the outcome is unpredictable. We examined if histopathologic parameters of traumatic neuromas have a prognostic value for recovery in relation to lingual nerve micro-neurosurgery. MATERIALS AND METHODS: Retrospective case study on neurosensory recovery after micro-neurosurgery. Outcome variables were as follows: pain perception, two-point discrimination, and sum score of perception, before and 12 months after micro-neurosurgery. Predictive histopathology variables included size, nerve tissue, and inflammation. Statistics are as follows: logistic and correlation analyses (P < 0.05). RESULTS: Sixty-five patients with lingual nerve damage were included in the study. Improved two-point discrimination was associated with small size of resected tissue (P = 0.0275). No normal appearing distal nerve tissue was associated with improved sum score of perception (P = 0.0185), higher final sum score of perception value (P = 0.0475) and final pain perception (P = 0.0324). Foreign body reaction was associated with no final pain perception (P = 0.0492). CONCLUSIONS: Small size, absence of distal nerve tissue, and no foreign body reaction were associated with improvement of the neurosensory functions. CLINICAL RELEVANCE: Histological parameters of the traumatic neuromas in routine preparation appeared to have some prognostic value for neurosensory functions as improvement of the neurosensory functions was associated with small size of resected tissue, no distal normal appearing nerve tissue, and no foreign body reaction.

Cross-tongue procedure: a new treatment for long-standing numbness of the tongue.

The lingual nerve may be injured during oral procedures, usually during extraction of lower third molars. Patients often complain of numbness of the hemitongue postoperatively. If this persists for 3 months or more, microsurgical exploration and reconstruction of the lingual nerve is required, and better outcomes are achieved after early repair. After 18-24 months the production of axoplasmic fluid through the axons of the proximal stump is reduced, and neurorrhaphy between the proximal and distal stumps is not recommended. In such cases we suggest that a portion of the opposite lingual nerve should be used as an additional nerve source.

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.

[Suture of lingual nerve: Technical note]. / Suture du nerf lingual: note technique.

INTRODUCTION: Because of its anatomical position, the lingual nerve may be severed during oral surgical procedures, such as third molar removal. Early suturing of the nerve promotes better recovery. We describe the end-to-end suture of this nerve. OPERATIVE PROCEDURE: The suture is carried-out under general anesthesia. The approach is made in the mouth floor, in the same way as for submandibular gland lithiasis transoral removal. This approach allows good exposure and some laxity to displace the nerve stumps. The latter can then be sutured under microscope assistance before closing the mucosa. DISCUSSION: Lingual nerve suture is a simple, quick and inexpensive procedure. Unlike other procedures, it cannot be used in case of large loss of substance because of the small amount of laxity of the nerve. Nerve function recovery is better if performed before the 6th post-traumatic month, and in young patients.