How to avoid iatrogenic lingual nerve injury in the retromolar area: an anatomical study of retromolar pad and lingual nerve.

PURPOSE: This study aimed to investigate the relationship between the retromolar gland and pad, and the relationship between the LN and retromolar gland/pad to establish a new landmark for avoiding LN injury. METHODS: Sixty-two lingual nerves from fresh-frozen cadavers were used for this study. The age of the specimens at the time of death ranged from 57 to 98 with a mean of 76.5 years. The mucous incision was made into the medial border of the retromolar pad and the submucosal tissue depth of the initial incision was bluntly dissected to expose the lingual nerve. When the LN was identified, the mucosa overlying the retromolar pad was removed to expose the retromolar gland to confirm if the retromolar pad corresponds to the retromolar gland. RESULTS: On all sides, the lingual nerve was found to course medial to the retromolar pad and inferior to the inferior border of the superior pharyngeal constrictor muscle to enter the sublingual space via the pterygomandibular space. The retromolar pad corresponded to the retromolar gland on all sides. This demonstrated that the retromolar pad is an overlying mucosa of the retromolar gland. No LN was found to travel through the retromolar gland. CONCLUSION: We suggest that the retromolar pad can be used as a new landmark for avoiding iatrogenic LN injury.

Prevention of Lingual Nerve Injury in Third Molar Surgery: Literature Review.

PURPOSE: To identify any factors that could aid the surgeon in preventing or minimizing the risk of lingual nerve injury during third molar surgery. MATERIALS AND METHODS: Electronic research was carried out on the correlation between lingual nerve damage and lower third molar surgery (topographic anatomy, surgical technique, and regional anesthesia) using PubMed, Scopus, and Cochrane central databases. The research included only articles published in English up to February 2016. RESULTS: Lingual nerve anatomy varied greatly: direct contact between the lingual nerve and the third molar alveolar wall was reported in a wide range of cases (0 to 62%) and the nerve was located at the same level or above the top of the ridge in 0 to 17.6% of cases. No detailed data were found on the actual incidence of lingual nerve injury resulting from local anesthesia by injection. Permanent lingual nerve damage did not show statistically relevant differences between the simple buccal approach and the buccal approach plus lingual flap retraction, although the latter was statistically associated with an increased risk of temporary damage. Lingual spit technique was statistically associated with an increased risk of temporary nerve damage than the buccal approach with or without lingual flap retraction. For permanent damage, no statistically relevant differences were found between the lingual split technique and the buccal approach with lingual flap retraction. Compared with tooth sectioning, the ostectomy was strongly statistically associated with permanent lingual nerve damage. CONCLUSIONS: Results should be interpreted with extreme caution because of the considerable heterogeneity of the data and the considerable influence of several anatomic and surgical variables that were closely related, but difficult to analyze independently. It seems preferable to avoid lingual flap elevation, except in selected cases in which the presence of more than 1 unfavorable surgical variable predicts a high risk of nerve injury. Tooth sectioning could decrease the extent of the ostectomy or even, in some cases, prevent it, potentially acting as a protective factor against lingual nerve injury.

The effect of modified surgical flap design for removal of lower third molars on lingual nerve injury.

AIM: The objective of this study was to evaluate a modified flap design for removal of lower third molars with avoidance of lingual flap elevation and its effect on postsurgical lingual nerve sensory impairment. MATERIALS AND METHODS: The patients included in this prospective study were those referred for removal of symptomatic lower third molars at two Oral and Maxillofacial Surgery clinics. Different patterns of impaction were included regarding the angulation and depth of the lower third molar. Patients were reviewed 1 day after surgery, then after 1 week. Each patient was examined at each recall visit for any sensory alterations of the lingual nerve. The data collected was correlated to several variables including the age, gender, side of operation, state of eruption, angulation, depth of impaction, and tooth division. RESULTS: A number of 53 patients (23 males and 30 females), at ages ranging from 16 to 43 years, underwent surgical removal of 66 fully or partially impacted lower third molars under local anesthesia using a modified flap design. The modified flap design provided adequate exposure for removal of the lower third molar for all patterns of impactions included, regarding the state of eruption, angulation, and depth of the tooth. CONCLUSION: This study showed that the investigated flap design can be safely used to remove lower third molars for different patterns of impaction without jeopardizing the lingual tissues thus providing optimum protection for the lingual nerve since it provided adequate exposure to remove the tooth without the reflection of a lingual flap.

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.

[Prevention of lingual nerve damage by removing stones from submandibular salivary gland duct]. / Profilaktika povrezhdenii yazychnogo nerva pri udalenii konkrementov iz protoka podnizhnechelyustnoi slyunnoi zhelezy.

The aim of the study was to elaborate lingual nerve sparing procedure of submandibular gland duct stones extraction. The study involved 43 patients with syalolithiasis treated in Oral Surgery Unit of Central Research Institute of Dentistry and Maxillofacial Surgery in 2013-2015. It was shown that to prevent lingual nerve and artery injury submandibular salivary gland duct should be dissected to the level of obstruction thus allowing adequate visualization of anatomical correlations especially when removing stones from the distal part of the duct.

[Anatomical rationale for lingual nerve injury prevention during mandibular block].

The topographic and anatomical study of lingual nerve structural features was done. It was revealed that during mandibular anesthesia possible lingual nerve injury can occur if puncture needle is lower than 1 cm. of molars occlusal surface level. The position of the lingual nerve varies withmandible movements. At the maximum open mouth lingual nerve is not mobile and is pressed against the inner surface of the mandibular ramus by the medial pterygoid muscle and the temporal muscle tendon. When closing the mouth to 1.25±0.2 cmfrom the physiological maximum, lingual nerve is displaced posteriorly from the internal oblique line of the mandible and gets mobile. On the basis of topographic and anatomic features of the lingual nervestructure the authors recommend the re-do of inferior alveolar nerve block, a semi-closed mouth position or the use the "high block techniques" (Torus anesthesia, Gow-Gates, Vazirani-Akinozi).

Piezoelectric osteotomy for distraction osteogenesis of the pediatric mandible.

BACKGROUND: Distraction osteogenesis of the mandible requires a complete osteotomy so that the proximal and distal segments may be separated, thereby producing length. One of the main complications of this technique is lingual nerve injury due to trauma induced by either the saw or the osteotome. The purpose of this article was to suggest the use of piezosurgery in performing near-complete osteotomy of either the body or ramus of the mandible. METHODS: Surgical procedure was performed under general anesthesia, and it lasted approximately 90 minutes. After the buccal cortex of the mandible was dissected, a piezosurgical device was used for the planned osteotomy. The gap created by the device allowed visualization of the nerve, thereby permitting completion osteotomy of the lingual cortex. The patient did not show any neurological postoperative complication. CONCLUSIONS: The use of piezoelectric surgery appears to be a safer option in performing distraction osteogenesis of the pediatric mandible. The presumed disadvantage of this technique, notably an increased operating time due to the lower power cut of the piezoelectric device, was not encountered.

The importance of a good evaluation in order to prevent oral nerve injuries: a review.

OBJECTIVE: Oral nerve injuries are a less frequent complication but they involve a decrease in the patient life quality. The purpose of the current review is to know the described risk factors to prevent injuries and to know the therapies against an established injury. MATERIALS AND METHODS: A Pubmed search of the English and Spanish language literature from 2000-2012 using the keywords 'oral surgery' or 'trigeminal nerve injuries' or 'lingual nerve injuries' or 'mandibular nerve injuries' was performed. Review articles were included and important articles from the references were added. RESULTS: A total of 662 were obtained from the search, from which 25 were selected accomplishing the inclusion criteria. Moreover, seven important articles were selected from the references of the ones mentioned, obtaining a total of 32 articles for the review. CONCLUSIONS: There is a relationship between the position of the extracted tooth and the incidence of the inferior alveolar nerve and lingual nerve injuries; as well as the age of the patient, the intra-operatory exposition of the nerve, the technique access for the lower third molar extraction and the surgeon's inexperience. The radiological examination is useful to evaluate the nerve damage and to decide on the surgical technique.

Piezosurgery for the lingual split technique in mandibular third molar removal: a suggestion.

BACKGROUND: The lingual split technique is a surgical procedure for extraction of impacted mandibular third molar throughout a lingual approach. The main disadvantage of this technique is the high rate of temporary lingual nerve injury mainly because of the trauma induced by the lingual flap retraction. The purpose of this paper is to suggest the use of piezosurgery in performing the lingual cortical plate osteotomy of the third molar alveolar process. METHODS: Surgical procedure was performed under general anesthesia, and it lasted approximately 60 minutes. After the buccal and lingual full-thickness flaps were incised and elevated, a piezosurgical device was used for osteotomy. A well-defined bony window was then removed, and it allowed the entire tooth was extracted in a lingual direction. The patient did not show any neurological postoperative complication. Lingual and inferior alveolar nerve functionality was normal before as well as after surgery. CONCLUSIONS: The use of piezoelectric surgery seems to be a good option in removing lower third molars when a lingual access is clearly indicated. The only disadvantage of this technique can be represented by an operating time lengthening possibly because of a lower power cut of the piezoelectric device, to the high mineralization of the mandibular cortical bone and to the use of inserts with a low degree of sharpening.

Transoral sialolitectomy combined with sialoendoscopy versus open submaxilectomy for the management of hilar lithiasis of the submandibular gland. / Sialolitectomía transoral combinada con sialoendoscopia versus submaxilectomía abierta para el manejo de litiasis hiliares de la glándula submaxilar.

INTRODUCTION: The treatment of salivary obstructive pathology by minimally invasive techniques has been an object of assessment by different studies for decades. Lithiasis at the level of the salivary duct will be the most frequent cause of obstruction, representing more than 50% of the pathology of the major salivary glands and almost 80% of these affecting the Wharton duct. MATERIAL AND METHODS: A prospective study comparing the results of combined transoral sialolitectomy (CTS) and open submaxillectomy techniques by cervicotomy in 2 groups of patients treated by lithiasis at the level of the hilum of the submaxillary gland. RESULTS: 22 patients were included in the study 16 (72.7%) were men and 6 (27.3%) were women, the average age was 54.41 years ± 12.75 (Min: 30/Max: 77). Regarding the variables associated with the disease: average lithiasis, size of the stone, hospital stay, lingual nerve alteration or complications for both techniques, differences were not found between both groups. There were only statistically significant differences in the average stay in favor of the CTS (P=.001). CONCLUSION: The minimally invasive approaches to the salivary ductal system, associated or not with sialoendoscopy, can be efficacy and can be associated with lower number of complications. The natural tendency should be aimed to gradually replacing open sialoadenectomy techniques, reserving its indication for the treatment of tumor pathology.

Oral surgery: part 4. Minimising and managing nerve injuries and other complications.

Many post-operative complications can be avoided with good patient selection, training and surgical planning. Obtaining explicit patient consent is also an essential component of treatment. The most significant complications from oral surgical interventions are iatrogenic trigeminal nerve injuries, which can result in permanent altered sensation and pain, causing considerable functional and psychological disability. This paper provides some useful suggestions on minimising the risks of these injuries. By understanding the risk factors and modifying the resulting intervention, more of these injuries may be prevented.

Evaluation of an innovative computer-assisted sagittal split ramus osteotomy to reduce neurosensory alterations following orthognathic surgery: a pilot study.

BACKGROUND: Sagittal split ramus osteotomy (SSRO) can be associated with postoperative neurosensory disturbances. This study aimed to evaluate the effectiveness of computer-assisted SSRO in reducing the incidence and severity of neurosensory alterations, using a surgical guide fabricated by computer-aided design and rapid prototyping (to guide bone cutting lateral to the inferior alveolar nerve). METHODS: A prospective double-blind, randomized controlled, clinical trial of computer-assisted SSRO vs conventional SSRO (assigned in a split-mouth design) in eight patients, mean age 23 (range 18-30) years, who participated in one session preoperatively and three sessions at 1 week and 1, 3 and 6 months postoperatively. At each session, subjective oral sensation was scored and quantitative sensory tests were performed. Neurosensory changes were compared between the two sides. RESULTS: The results showed that on the computer-assisted SSRO sides, patients had lower postoperative abnormal thresholds for the Semmes-Weinstein monofilaments on lower lip and chin (p < 0.05 at 3 months) and for the two-point discrimination on lower lip (p < 0.05 at 1 week) and chin (p < 0.05 at 6 months), with fewer abnormal self-reported changes in lower lip sensation (p < 0.05 at 1 week) after surgery. CONCLUSIONS: These findings imply that computer-assisted SSRO is associated with better levels of neurosensory function after surgery.

Clinical anatomy of the lingual nerve and identification with ultrasonography.

Our objective was to investigate the pathway of the lingual nerve and find out whether it can be identified using ultrasonography (US) intraorally. It is a dominant sensory nerve that branches from the posterior division of the mandibular aspect of the trigeminal nerve, and is one of the two most injured nerves during oral surgery. Its anatomy in the region of the third molar has been associated with lingual nerves of variable morphology. If surgeons can identify its precise location using US, morbidity should decrease. We searched published anatomical and specialty texts, journals, and websites for reference to its site and US. Cadavers (28 nerves) were dissected to analyse its orientation at the superior lingual alveolar crest (or lingual shelf). Volunteers (140 nerves) had US scans to identify the nerve intraorally. Our search of published books and journals found that descriptions of the nerve along the superior lingual alveolar crest were inadequate. We found no US studies of the nerve in humans. Dissections showed that the nerve was above (n=6, 21%) and below (n=22, 79%) the crest of the lingual plate. US scans showed 140 lingual nerves intraorally in 70 volunteers. The nerve lay either above or below the superior lingual alveolar crest, which led us to develop a high/low classification system. US can identify the lingual nerve and help to classify it preoperatively to avoid injury. Our results suggest that clinical anatomy of the lingual nerve includes the superior lingual alveolar crest at the third and second molars because of its surgical importance. US scans can successfully identify the nerve intraorally preoperatively.

Coronectomy: a surgical option for impacted third molars in close proximity to the inferior alveolar nerve.

BACKGROUND: Damage to the inferior alveolar nerve (IAN) during the extraction of impacted mandibular third molars in close proximity to the mandibular canal is a postoperative complication that most frequently occurs in patients 40 years and older. METHODS: The authors evaluated the postoperative complications of 43 coronectomies of impacted mandibular third molars in 37 patients (17 men and 20 women, mean age [standard deviation] 31 [2] years). The authors used cone-beam computed tomographic images to determine that all of the teeth that underwent a coronectomy were in close proximity to the IAN. RESULTS: The authors did not observe neurological injuries to the IAN or to the lingual nerve. One patient complained of intermittent pain and, 10 months after undergoing the coronectomy, underwent a second operation for extraction of the root fragments. The root extraction did not result in any neurological deficits, because the root fragments had migrated from the mandibular canal. One case of alveolitis was reported that manifested 15 days after the coronectomy. CONCLUSIONS: Coronectomies are safer to perform than complete extractions in situations in which the third molar is in close proximity to the mandibular canal. Root migration generally is asymptomatic, but in a case in which the patient underwent a second operation, the risk of the patient's experiencing neurological injuries was reduced. CLINICAL IMPLICATIONS: Coronectomy appears to be a valid surgical alternative in patients 40 years and older who are at a higher risk of experiencing neurological deficits than are younger patients.

Piezoelectric-assisted removal of a benign fibrous histiocytoma of the mandible: an innovative technique for prevention of dentoalveolar nerve injury.

In this article, we present our experience with a piezoelectric-assisted surgical device by resection of a benign fibrous histiocytoma of the mandible.A 41 year-old male was admitted to our hospital because of slowly progressive right buccal swelling. After further radiographic diagnosis surgical removal of the yellowish-white mass was performed. Histologic analysis showed proliferating histiocytic cells with foamy, granular cytoplasm and no signs of malignancy. The tumor was positive for CD68 and vimentin in immunohistochemical staining. Therefore the tumor was diagnosed as primary benign fibrous histiocytoma. This work provides a new treatment device for benign mandibular tumour disease. By using a novel piezoelectric-assisted cutting device, protection of the dentoalveolar nerve could be achieved.