• The Journal of the Korean dental association
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• v.46 no.6
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• pp.384-393
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• 2008

Many dental surgeries including implant surgery, orthognathic surgery etc, have possibility of neurologic injury. As neurosensory dysfunction has no definitive treatment modality and shows slow recovery, patients have discomforts and make the legal conflicts with surgeons. The purpose of this study was to survey the types and subjective evaluation of patients with neurosensory dysfuction after dental surgery. This study included 66 patients with postoperative neurosensory dysfunction who were operated at Seoul National University Bundang Hospital from Dec 2003 to Jun 2007. Male were 28 and female were 38. Age was from 17 to 74 years old. The results of subjective evaluation of neurosensory dysfunction were as followings. 1. The sites of the altered sensation were chin, lip, tooth, tongue and so on. 2. 40.7% of the patients didn't explain accurately about their symptoms. 29.2% of the patients expressed anesthesia and 26.2% mild discomfort. 3. The altered sensation was expressed mostly in touching, mastication and speaking. 52.3% of the patients suggested that their symptoms always existed. 4. Neuropathic pain existed in 44.6% of the patients. 48.3% of the patients suggested that pain was triggered by touching. Neuropathic pain always existed in 41.4% of the patients. 5. Patients showed negative responses on the question that they will take operations which cause the risk of neurosensory dysfunction in the future. The objective and subjective evaluation about the altered sensation after nerve injury nerver coincide. The subjective complaint can affect the result of treatment and daily life negatively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.1
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• pp.53-60
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• 2002

Neurosensory dysfunction of the injured inferior alveolarnerve(IAN) is a common and distrssing consequence of traumatic or iatrogenic injury. Conventional neurosensory testing has been used to detect and monitor sensory impairments of the injured IAN. However, these tests had low reliability and are not qualitative at best because they are based on solely on the patient's subjective assesment of symptoms. Consequently, there is need for more reliable, sensitive, and objective test measures to document and to monitor sensory dysfunction of the trigeminal nerve. This study was to investigate DITI's (digital infrared thermographic imaging) potential as a diagnostic alternative for evaluating of the nerve injures and sensory disturbance. Subjects were 30 patients who had been referred to Ewha Medical Center due to sensory disturbance of the lower lip and chin followed after unobserved inferior alveolar nerve injuries. The patients were examined by clinical neurosensory tests as SLTD (static light touch discrimination), MDD (moving direction discrimination), PPN (pin prick nociception) and DITI (digital infrared thermographic imaging). The correlation between clinical sensory dysfunction scores(Sum of SLTD, MDD, PPN, NP, Tinel sign) and DITI were tested by Spearman nonparametric rank correlation anaylsis & Kruskal-Wallis test, Wilcoxon 2-sample test. This study resulted in as follows; (1) The difference of thermal difference between normal side and affected side was as ${\Delta}-3.2{\pm}0.13$. (2) The DITI differences of the subjects presenting dysesthesia of the lip and chin were correlated significantly with the neurosensory dysfunction scores(r=0.419, p=0.021)and SLTD (r=0.429, p<0.05). (3) The MDD, PPN, NP, Tinel sign, duration, gender were not correlated with DITI(p> 0.05). Therefore, the DITI(digital infrared thermographic imaging) can be an option of the useful objective diagnostic methods to evaluate the injured inferior alveolar nerve and sensory dysfunction of trigerminal nerve.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.3
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• pp.226-231
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• 2001

Modified surgical technique for transposition of the inferior alveolar nerve followed by immediate placement of endosseous implants in mandibles with moderate to severe atrophy are presented. Five transpositions of the inferior alveolar nerve together with the installation of 10 implants were performed in four patients. The mean postoperative follow-up time was 17 months, with a range of 8 to 20 months. All implants with functioning pontics remained stable, with no mobility or symptoms of pain and infection during the follow-up period. Neurosensory evaluation was performed using the two-point discrimination test. Two patients had objective neurosensory dysfunction at postoperative, but all the nerve function were reported as normal by the patients 4 months postoperatively.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.2
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• pp.144-154
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• 2001

Dysfunction of the inferior alveolar nerve indicated by various degree of numbness of the lower lip and chin is one of the few drawbacks of mandibular osteotomy, especially Bilateral Sagittal Split Ramus Osteotomy(BSSRO) and genioplasty. Although it has been recorded throughout the history of this techniques, it is true etiology poorly understood. In this study, 22 consecutive patients under class III malocclusiion impression and undergoing orthognathic surgery(BSSRO only 11 case, BSSRO with genioplasty 11 case) were studied using 4 neurosensory test(static light touch, directional discrimination, two-point discrimination, pin pressure nociception) with post OP 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, On control group, 10 members without trauma and nerve damage history, nerve test was accomplished. We concluded majority of patients return of sensation during post operative 24 weeks. Althought immediate nerve deficit are 92.2%, 97.2% 88.9% these are recovered to 25%, 35.72%, 10.71% at 24 weeks. Nerve recovery rate increased prominently between post 4 weeks and 8 weeks. There is no statistically difference about neurosensory deficit among the chin area. Neurosensory deficit more severe when the BSSRO with genioplasty group than the only BSSRO group. Immediate neurosensory deficit is larger left side than right side but after 6 months, there is no significantly difference between left side and right side. Static light touch and pin pressure nociception are more sensitive method of neurosensory deficit than two point discrimination.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.1
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• pp.41-48
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• 2020

Objectives: One of the most common complications of bilateral sagittal split ramus osteotomy (BSSRO) is neurosensory impairment of the inferior alveolar nerve (IAN). Accurate preoperative determination of the position of the IAN canal within the mandible using cone-beam computed tomography (CBCT) is recommended to prevent IAN dysfunction during BSSRO and facilitate neurosensory improvement after BSSRO. Materials and Methods: This randomized clinical trial consisted of 86 surgical sites in 43 patients (30 females and 13 males), including 21 cases (42 sides) and 22 controls (44 sides). Panoramic and lateral cephalographs were obtained from all patients. In the experimental group, CBCT was also performed from both sides of the ramus and mandibular body. Neurosensory function of the IAN was subjectively assessed using a 5-point scale preoperatively and 7 days, 1 month, 3 months, 6 months, and 12 months post-surgery. Data were analyzed using Fisher's test, Spearman's test, t-test, linear mixed-model regression, and repeated-measures ANCOVA (α=0.05, 0.01). Results: Mean sensory scores in the control group were 1.57, 2.61, 3.34, 3.73, and 4.20 over one year and were 1.69, 3.00, 3.60, 4.19, and 4.48 in the CBCT group. Significant effects were detected for CBCT intervention (P=0.002) and jaw side (P=0.003) but not for age (P=0.617) or displacement extent (P=0.122). Conclusion: Preoperative use of CBCT may help surgeons to practice more conservative surgery. Neurosensory deficits might heal faster on the right side.

• Journal of Oral Medicine and Pain
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• v.39 no.4
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• pp.133-139
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• 2014

Purpose: There have been reports regarding the various factors associated with the level of discomfort and recovery from neurosensory symptoms in patients with trigeminal nerve injury. However, the contributing factors remain uncertain and poorly understood. The purpose of this paper was to investigate the possible association between various factors expected to affect neurosensory discomfort and recovery in patients with mandibular nerve injury after dental implant surgery. Methods: Eighty-nine post-dental implant surgery patients with mandibular nerve injury were enrolled in this retrospective analysis. A medical records review of the patients was done to determine if the patients' improvement was related to pain intensity, the length of time between the injury and removal of the implant or the depth of penetration of the implant into the mandibular canal as determined by cone-beam computed tomography. Results: There was no significant linear relationship between pain intensity and symptomatic improvement (p=0.319). There was no significant linear relationship between the level of mandibular canal penetration and either pain intensity (p=0.588) or symptomatic improvement (p=0.760). There was a statistically significant linear relationship between length of time before the injury was treated, both with pain intensity (p=0.004), and symptomatic improvement (p=0.024). Conclusions: Our findings indicate that the length of time between nerve injury and initiation of conservative treatment is more closely related to the pain intensity and symptomatic improvement than other factors, including the level of mandibular canal invasion. Additionally, increased pain intensity and decreased symptomatic improvement can be expected over time, because of this linear trend. Therefore, although direct injury to the nerve is the most important factor contributing to a neurosensory disturbances, early neurosensory assessment and initiation of conservative treatment should be done to optimize recovery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.3
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• pp.250-257
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• 2001

Sensory dysfunction following the injury of the inferior alveolar nerve requires objective examination to get a reproducible data and to provide necessary treatment. This study was designed to evaluate if the SEP(somatosensory evoked potentials) of the mental nerve can be used as an objective method for the diagnosis of nerve injury and sensory disturbances. The subjects were nineteen patients ($37.4{\pm}11.3$ years old) who had been suffered from sensory disturbance of the unilateral lower lip and mental region for over 6 months after the inferior alveolar nerve injuries confirmed by the microsurgical explorations. The clinical neurosensory tests as SLTD(static light touch discrimination), MDD(moving direction discrimination), 2PD(two point discrimination), PPN(pin prick nociception) and accompanied pain were preceded to electro-physiologic examinations as SEP. The score of sensory dysfunction (sum score of all sensory tests) ranged from 0 to 8 were compared to the latency differences of the mental nerve SEPs. The correlation between clinical sensory scores and SEPs were tested by Spearman nonparametric rank correlation analysis, the differences in SEP latency by Kruskal-Wallis test and the latency differences according to PPN and accompanied pain by Mann-Whitney U test. This study resulted that the difference of the latencies between normal side and affected side was $2.22{\pm}2.46$ msec and correlated significantly with the neurosensory dysfunction scores (p=0.0001). Conclusively, the somatosensory evoked potentials of the mental nerve can be a useful diagnostic method to evaluate the inferior alveolar nerve injuries and the change of sensory dysfunction to be reproduced as an objective assessment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.3
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• pp.183-189
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• 2021

Objectives: To assess the prevalence and recovery of inferior alveolar nerve dysfunction (IAND) in mandibular fractures. Materials and Methods: This was a prospective cohort study. Clinical neurosensory testing was done preoperatively and the IAND was categorized as mild, moderate or severe. Postoperatively, neurosensory testing was repeated at 1 day, 1 week, 1 month, 3 months and every 3 months thereafter. Results: A total of 257 patients with 420 fractures were included in the study with a mean age of 31.7 years. Body fractures (95.9%) had the highest incidence of IAND, followed by the angle fractures (90.1%) and symphysis fractures (27.6%). The condyle and coronoid fractures did not have any IAND and hence were excluded from further study. After eliminating those cases, 232 patients remained in the study with 293 fractures. The overall prevalence of IAND in fractures occurring distal to the mandibular foramen was 56.3%. The changes until 1 week were minimal. From 1 month to 6 months, there was a significant reduction in the severity of IAND. A significant number of cases (60.0%) were lost to follow-up between 6 and 9 months. At 6 months, 23.9% of cases still had some form of IAND and 95.0% of the symphysis, 59.0% of the angle and 34.8% of the body fractures with IAND had become normal. Conclusion: This study documents the reduction in the degree of severity of IAND in the first six months and provides the basis for future studies with longer periods of follow-up.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.25.1-25.4
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• 2016

Background: Bilateral sagittal split ramus osteotomy (BSSRO) is the most widely used mandibular surgical technique in orthognathic surgery and is easy to relocate the distal segments, accelerating bone repair by the large surface of bone contact. However, it can cause neurosensory dysfunction (NSD) or sensory loss by injury of the inferior alveolar nerve. The purpose of the present study was to evaluate NSD after BSSRO and modifiers at NSD recovery. Methods: In this study, NSD characteristics after BSSRO from 2009 to 2014 at the Kyung Hee University Dental Hospital were evaluated. The pattern of sensory recovery over time was also evaluated based on factors such as field of sensory dysfunction, surgical procedure, presence of pre-operative facial asymmetry, and postoperative medications. Results: Most of the patients had shown NSD immediately after orthognathic surgery. Among the 1192 sides of 596 patients, NSD was observed in 953 sides and 544 patients. Sexual predilection was shown in males (p value = 0.0062). In the asymmetric group of 132 patients, NSD was observed in 128 patients (96.97 %). In the symmetric group of 464 patients, NSD was observed in 416 patients (89.45 %); on the other hand, NSD was observed significantly higher in the asymmetric group (p = 0.025). NSD-associated factors were analyzed, and vitamin B12 may be beneficial for NSD recovery. Conclusions: There was a difference between the symmetric group and the asymmetric group in NSD recovery. Vitamin B12 can be regarded as an effective method to nerve recovery. However, a further prospective study is needed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.16.1-16.8
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• 2020

Background: Cyst enucleation, which extracts only the tumor with the application of Carnoy's solution (CS), has been suggested as a conservative treatment with a low recurrence rate and morbidity. However, there has been a concern that CS's contact with inferior alveolar nerve (IAN) can cause neurons to degenerate and cause sensory dysfunction. The purpose of this retrospective cohort study aimed to investigate the neurosensory function after surgical treatment with or without the application of CS. Methods: While controlling the effects of sex, age, follow-up period, and invasion size of the tumor, we performed the binary logistic regression analysis to examine whether or not the sensory function of the patients who were treated with CS (n = 19) for the cyst enucleation procedure was significantly different from those who were not treated with CS (n = 58) at the end of the follow-up period. Results: The logistic regression result showed that the use of CS was not significantly related to the normalness of sensory function at the end of the follow-up period. Rather, the invasion size of the cyst was significantly associated with sensory dysfunction. Conclusions: CS may be used for patients who are diagnosed with OKC and UAM without much fear of its impact on sensory dysfunction. However, a small number of patients who were treated with CS experienced severe sensory damage and did not recover at the end of the follow-up period, suggesting the need for further analysis of these patients.