Botulinum toxin type A improves pain in numb chin syndrome.

Numb chin syndrome is a rare pain disorder characterized by decreased sensation and paresthesia in the territory of the mental nerve. Neuropathic pain is sometimes described in this setting, and the most common treatments include oral analgesics, gabapentinoids, and carbamazepine; however, botulinum toxin type A has never been used in this setting. We describe a case of bilateral numb chin syndrome, secondary to Burkitt lymphoma, associated with refractory and persistent burning neuropathic pain, effectively treated twelve times with subcutaneous Botulinum toxin type A (BoNT/A) injections. The procedure was well tolerated, but the patient reported incomplete mouth closure of minimal entity. BoNT/A could be a safe and effective therapy for neuropathic pain associated with numb chin syndrome.

What Do I Do if There is No Distal Nerve Stump for Inferior Alveolar Nerve Reconstruction?

This technical note describes an innovation that addresses a clinical problem in inferior alveolar nerve (IAN) reconstruction. In some cases of mandibular resection, there is a need to resect a significant amount of the IAN along with the pathologic lesion and this may result in a lack of a distal nerve stump for completion of the neural anastomosis. This technical note offers the option to perform the distal neurorrhaphy into the residual soft tissues with the expectation that axonal sprouting will occur and result in lower lip and chin sensory reinnervation. There are no inherent risks or additional costs. The significance of this technique is that it permits IAN reconstruction in cases where the actual nerve stump is not available and improves patient care. There should be no challenges or delays to implementing this innovation for surgeons who reconstruct the IAN during ablative mandibular resection.

[Evaluation of the effect of simultaneous neuralized iliac bone flap on the preservation of lower lip and chin sensation during mandibular reconstruction].

PURPOSE: To evaluate the effect of reconstructing inferior alveolar nerve and preserving the sensation of lower lip and chin in repairing mandibular defect by simultaneous neuralized iliac bone flap. METHODS: Patients with continuous mandibular defects requiring reconstruction were randomly assigned to the innervated(IN) group and the control(CO) group by random number table. In the IN group, the deep circumflex iliac artery and recipient vessels were anastomosed microscopically during mandible reconstruction, and the ilioinguinal nerve(IN), mental nerve(MN) and inferior alveolar nerve(IAN) were anastomosed at the same time. In the CO group, only vascular anastomosis was performed without nerve reconstruction. During the operation, the nerve electrical activity after nerve anastomosis was detected by nerve monitor, and the sensory recovery of lower lip was recorded by two-point discrimination(TPD), current perception threshold (CPT) and Touch test sensory evaluator(TTSE) test. SPSS 26.0 software package was used for data analysis. RESULTS: According to the inclusion and exclusion criteria, a total of 20 patients were included, with 10 patients in each group. All the flaps survived in both groups, and no serious complications such as flap crisis occurred, and no obvious complications occurred in the donor site. The results of TPD test, CPT test and TTSE test all indicated that the degree of postoperative hypoesthesia in the IN group was less(P＜0.05). CONCLUSIONS: Simultaneous nerve anastomosis vascularized iliac bone flap can effectively preserve the feeling of lower lip and improve the postoperative quality of life of patients. It is a safe and effective technique.

Numb chin syndrome: What all oral health care professionals should know.

BACKGROUND: Numb chin syndrome (NCS) is a rare sensory neuropathy involving the mental nerve. Symptoms of NCS are often overlooked because of their apparent innocent nature; however, owing to the frequent association of NCS with malignancies, the opposite should be the rule. Oral health care professionals may be the first to encounter patients with NCS and should be aware of its clinical characteristics in an effort to decrease patient morbidity and mortality. TYPES OF STUDIES REVIEWED: A search in PubMed (MEDLINE) and the Cochrane Library was performed using the terms numb chin syndrome, numb chin, mental neuropathy, mental nerve neuropathy, and malignant mental nerve neuropathy, yielding 2,374 studies. After inclusion and exclusion criteria were applied, 102 studies remained. Descriptive statistics were performed, analyzing the etiology responsible for NCS, characteristics of NCS including associated symptoms, unilateral or bilateral nature, and information on professionals visited and examinations requested to make a diagnosis. RESULTS: NCS was associated with malignancy in 29% through 53% of the published cases. Twenty-eight percent of patients initially consulted an oral health care professional with the symptom of a numb chin. Patients more likely to have NCS were those from the ages of 61 through 70 years; 74% were unilateral; and the most common symptoms reported were numbness (100%), paresthesia (18%), and pain (17%). Forty-seven percent of the NCS cases were associated with a recurrent malignancy, and the most prevalent associated diagnoses were breast cancer (32%) and lymphoma and leukemia (24%). CONCLUSIONS: Oral health care professionals should be aware of the characteristics of NCS as they may be the first health care providers consulted for these symptoms. PRACTICAL IMPLICATIONS: A thorough medical and dental history as well as a complete cranial nerve screening should be performed on all patients, especially those with numbness, as this may prevent misdiagnosis and allow a timely referral and a substantial improvement of treatment course and prognosis.

Numb chin syndrome. / Nummen hake.

BACKGROUND: Numb chin syndrome describes sensory neuropathy characterised by numbness in the distribution of the terminal branch of the mandibular division of the trigeminal nerve. This symptom may be overlooked by patients and clinicians due to its mild nature; however, it could represent a serious underlying pathology such as inflammatory conditions or malignancy. CASE PRESENTATION: A man in his seventies presented with isolated numbness on the right side of the chin, and no other neurological or constitutional symptoms. Radiology showed a lytic mass in the right side of the mandible protruding through the mental foramen. A multidisciplinary approach revealed the cause of the patient's numb chin syndrome. INTERPRETATION: This case report illustrates clinical considerations in a patient with numb chin syndrome.

Numb chin syndrome secondary to infiltration of inferior alveolar nerve as a presentation of relapse in treated testicular lymphoma-diagnosis on PET/CT and MR neurography.

Numb chin syndrome (NCS) is a rare presentation of primary or recurrent malignant neoplasms among other non-neoplastic causes. The syndrome is characterized by altered sensations in the distribution of the mental nerve and presents with pain and paresthesias along the distribution of the inferior alveolar nerve and its branches. The primary diagnosis is indicated while following up patients through positron emission tomography/computed tomography (PET/CT) when a hypermetabolic focus is seen in the vicinity of the angle of the mandible. Further anatomical localization is performed using magnetic resonance (MR) neurography and postcontrast MR imaging, which demonstrates neural involvement. We hereby describe a case of a 56-year-old man, a treated case of DLBCL (diffuse large B-cell lymphoma), presenting with NCS and diagnosed with perineural invasion through PET/CT and further MR evaluation. To our knowledge, there are no other reports in the literature describing the MR neurography appearance of the inferior alveolar nerve in NCS. We hereby stress on the use of MR neurography followed by postcontrast 3D sequences with multiplanar reformatting for adequate lesion detection.

Numb chin syndrome in sickle cell disease: a case series of Jamaican patients.

Numb chin syndrome is an uncommon presentation that has been reported as secondary to metastatic disease, trauma, and infections of the maxilla, mandible, or oral cavity. The hypoesthesia, paraesthesia, or pain are a result of injury to the inferior alveolar nerve, which is particularly vulnerable as it exits the mandible through the mandibular foramen as the mental nerve. In persons with sickle cell disease, it has been reported as a manifestation of mandibular vaso-occlusive crisis. This case series presents 13 patients with sickle cell disease who presented with numb chin syndrome, the largest number of cases that has been described in the literature to date. The report illustrates the wide variety of presentations and therefore possible differential diagnoses to consider. In this case series, the symptoms were associated with vaso-occlusive crises, allergic reactions, dental infections, malignancy, rheumatoid arthritis, and pregnancy. Most appeared to be self-limiting; however, one patient was having his second episode, and the numbness has persisted in three patients. The series illustrates that it is important not only to ensure that the source of the local vaso-occlusive crisis is treated, but also to not miss important differentials such as metastatic disease, where this can be the first presentation of malignancy and would represent a very poor prognosis. There is no reported successful treatment for the hypoesthesia in this case series, and this presents an area for further research.

Numb chin syndrome as a presentation for acute myeloid leukemia relapse post-hematopoietic cell transplant: Case report and review of literature.

NCS is defined as reduced or absent sensation in the chin and lower lip within the distribution of the mental or inferior alveolar nerves. Although commonly associated with local trauma, NCS can indicate an underlying malignancy or can be the presenting symptom of cancer recurrence. We describe a 6-year-old female patient with AML and t(8,21) who underwent allogeneic HCT. Five months post-HCT, the patient presented with right-sided facial pain and numbness in her chin and lower lip consistent with NCS. Two weeks later, the patient had bone marrow relapse indicating AML recurrence. Although NCS remains a rare diagnosis especially in children, in the context of leukemia, it usually indicates an advanced disease or could be a sign of recurrence, and is commonly associated with grim prognosis. Further research is needed to study the link between NCS and specific cytogenetic abnormalities.

A case report: Numb Chin Syndrome due to thalamic infarction: a rare case.

BACKGROUND: Numb Chin Syndrome (NCS), which is also characterized as sensory neuropathy of the mental nerve, describes a mostly unilateral numbness of the chin and lower lip. Benign and malignant diseases are known to cause this circumscribed symptom, which can easily be overlooked or misdiagnosed. In this article we present the very rare case of a clinical NCS caused by thalamic lacunar infarction. As a pure sensory stroke it is a rare variant of the Cheiro-Oral Syndrome (COS). CASE PRESENTATION: A 63-year-old male patient received an emergency referral to our department after the patient had noticed a feeling of numbness of the left lower lip and chin on the previous day. The neurological examination revealed an approximately 2 × 3 cm area of hypoesthesia in the area of the chin and left lower lip and the cranial MRI an acute ischemia in the right thalamus. CONCLUSIONS: In this case report we introduce a patient who clinically shows an NCS. Various diseases may be responsible for NCS, including malignancies or even central neurological disorders such as multiple sclerosis. A lacunar thalamic ischemia as a cause of NCS is very rare and to our knowledge described in the literature only in the contex of a COS in three cases. We wish to remind the reader, through this case, of the purely descriptive and syndromal character of the NCS and the importance for detecting underlying diseases. Furthermore we give a brief overview of the NCS and causative disorders.

Evaluation of accuracy and sensory outcomes of mandibular reconstruction using computer-assisted surgical simulation.

PURPOSE: To introduce a modified protocol for mandibular reconstruction and evaluate the protocol using a standardized assessment method. METHOD: This retrospective study involved a case series of nine patients who underwent mandibular reconstruction between 2015 and 2017. The modular protocol comprised three novel modifications in terms of computer-assisted surgical simulation (CASS); surgical template (ST), and surgical procedure. The standardized postoperative evaluation consisted of operation time, part comparison analysis (PCA), facial symmetry, and mechanical quantitative sensory testing. RESULTS: The surgery successfully removed the affected mandible and preserved the inferior alveolar neurovascular bundle (IANB). PCA revealed that the mean error and standard deviation were 0.92 and 0.96 mm, respectively, for all mandibular surface sites. Follow-up results showed good facial symmetry, existence of sensation in lower lip, and no significant differences in pulp vitality between both sides (p = 0.181). Also, the results showed a reduction in the overall operating time. CONCLUSION: The modified mandibular reconstruction method used in this study could repair lateral mandibular defects and preserve the sensory function of the chin and lower lip.

Experimental Study on Involvement of the Central Nervous System in Inferior Alveolar Nerve Damage-Associated Hyperalgesia of the Mental Region.

PURPOSE: Involvement of the central nervous system in sensory disturbances of the mental region occurring after inferior alveolar nerve damage was investigated using a rat model of inferior alveolar nerve damage. PATIENTS AND METHODS: The rat inferior alveolar nerve was damaged by ligation with thread, and the course of behavioral changes after surgery was observed for 42 days. In addition, activation of microglia and astroglia in the trigeminal spinal subnucleus caudalis (Vc) was analyzed using immunohistochemistry. c-Fos-positive cells were quantitatively evaluated to analyze the state of neuron excitement. RESULTS: The withdrawal threshold was significantly decreased 5 days after surgery in the inferior alveolar nerve-ligated (IANL) group compared with that in the sham group and subsequently recovered over time. In addition, microglia and astroglia were activated in the Vc region 5 days after surgery in the model group, and c-fos-positive cells were also significantly more frequent in the IANL group. However, no significant difference in the withdrawal threshold was seen between the IANL and sham groups on day 42, nor were any significant differences seen in the amounts of microglia, astroglia, or c-fos-positive cells. CONCLUSIONS: Interactions among microglia, astroglia, and neurons in the central nervous system might be involved in the progression of inferior alveolar nerve damage-associated mental hyperalgesia to a chronic state.

Computer-guided chin harvest: A novel approach for autogenous block harvest from the mandibular symphesis.

BACKGROUND: The introduction of CAD/CAM technology allowed clinicians to carry out complex procedures with a high level of precision and reproducibility and minimize the risk of injury during the procedure. PURPOSE: The aim of the present study is to evaluate the efficacy of the CAD/CAM surgical guide during chin harvesting procedures in reducing the risk of neurosensory damage and patient morbidity compared with the standard technique. MATERIALS AND METHODS: About 20 cases of autogenous block chin harvest were randomly into two groups. The first group received computer-guided chin block harvest while the second group received autogenous block chin harvest using the standard approach. RESULTS: In the guided group, out of the 10 subjects, 2 subjects presented with wound dehiscence which resolved within 1 month. No teeth showed any negative pulp sensitivity results. The pointed-Blunt test and 2 point discrimination tests showed a single case of neurodeficits at 1 week follow-up appointment which resolved within 1 month. In the nonguided group, out of the 10 subjects, 1 case presented with wound dehiscence that resolved completely within 1 month. Pulp vitality test showed negative results in 29.4% of the involved teeth at 1 week which decreased to 9.8% and 3.9% at 1 and 6 months follow-up, respectively. The pointed blunt test revealed 3 subjects with neurodeficits at 1 week, out of which 2 subjects showed persisting symptoms at 6 months follow-up. The 2 point discrimination test showed 3 subjects with neurodeficits, out of which two subjects showed persistent symptoms with no resolution at the 6 months follow-up. CONCLUSION: Within the limits of this study, computer-guided chin harvest shows promising results in the reduction of neurosensory complications following harvesting procedures and presents as a safe alternative to the standard technique.

Digital Relief of the Mental Foramen for a CAD/CAM-Fabricated Mandibular Denture.

Relief of the intaglio surface of a denture base is conventionally performed using thin wax and soft metal foil attached to the master cast. The following report highlights a new relief procedure for the mental foramen using a CT double scan technique on the CAD/CAM dentures fabricated for the patient with paresthesia of the left lower lip and chin during mastication.

Burkitt non-Hodgkin lymphoma presenting with mental neuropathy ('numb chin' syndrome) in an HIV-positive patient.

Mental nerve neuropathy is usually due to local trauma or dental causes, but may be a manifestation of malignancy. A patient with virologically controlled human immunodeficiency virus (HIV) infection presented with a 'numb chin' on the background of long-standing night sweats, malaise and weight loss, worsening respiratory symptoms, and lymphadenopathy. Burkitt non-Hodgkin lymphoma was diagnosed from histology of a lymph node. Imaging (magnetic resonance imaging and 18fluorodeoxyglucose [FDG]-positron emission tomography-computed tomography [PET-CT]) showed abnormal intracranial enhancement of the right mandibular nerve and extensive 18FDG-avid lymphadenopathy above and below the diaphragm, focal lesions in the spleen and within the right mandible. The patient received chemotherapy and remains in clinical and radiological remission seven years later. This case highlights the need for clinicians to maintain a high index of suspicion for underlying malignancy when an HIV-infected patient presents with new onset of a 'numb chin'. Additionally, it demonstrates the importance of functional 18FDG-PET-CT and neuroimaging in order to identify site(s) of pathology.

Intraoral Observation of the Mentalis and Incisivus Labii Inferioris Muscles.

The mentalis (MT) and the incisivus labii inferioris (ILI), which are accessory muscles of the orbicularis oris (OO) muscle, form an intertwined and three-dimensionally related complex. The purpose of this study is to clarify the relationship between the MT, ILI, and OO muscles via intraoral dissection. Twenty-two sides from 11 fresh adult Caucasian cadaveric heads were used, and the MT, ILI, and OO dissected under the surgical microscope. Next, measurements of the bony attachment were carried out on another 12 sides. The fibers of the MT were separated into 2 parts: a superior and an inferior part with the former coursing anteromedially and joining the inferior part of the OO. The latter coursed anteroinferiorly to the skin of the chin. The ILI traveled anterolaterally and joined the inferior part of the OO. Inferior labial branches of the mental nerves ran on the OO. There was a significant difference (P = 0.0001) between specimens that were edentulous or had severe periodontitis with regard to the distance from the alveolar ridge to the upper side of the quadrangle when compared with specimens with mild periodontitis. However, there was no significant difference (P > 0.05) between specimens that were edentulous or had severe periodontitis specimens with mild periodontitis with regard to the distance from the inferior border of the mandible to the lower side of the quadrangle. We believe that the observations of this study could help surgeons better understand the anatomy of the chin and minimize complications following surgical and other invasive procedures in this area.

Numb chin with mandibular pain or masticatory weakness as indicator for systemic malignancy - A case series study.

BACKGROUND/PURPOSE: Numb chin syndrome (NCS) is a critical sign of systemic malignancy; however it remains largely unknown by clinicians and dentists. The aim of this study was to investigate NCS that is more often associated with metastatic cancers than with benign diseases. METHODS: Sixteen patients with NCS were diagnosed and treated. The oral and radiographic manifestations were assessed. RESULTS: Four (25%) of 16 patients with NCS were affected by nonmalignant diseases (19% by medication-related osteonecrosis of the jaw and 6% by osteopetrosis); yet 12 (75%) patient conditions were caused by malignant metastasis, either in the mandible (62%) or intracranial invasion (13%). NCS was unilateral in 13 cases and bilateral in three cases. Mandibular pain and masticatory weakness often dominate the clinical features in NCS associated with cancer metastasis. In two patients, NCS preceded the discovery of unknown malignancy (breast cancer and leukemia). In nine others, NCS heralded malignancy relapse and progression. Metastatic breast cancer in four (36%) cases accounted for the most common malignancy. Other metastatic diseases included two multiple myelomas, and one each of leukemia, prostate cancer, colon cancer, lung cancer, maxillary sinus adenoid cystic carcinoma and adrenal gland neuroblastoma. Radiographic examinations showed obvious mandibular metastasis with compression of the inferior alveolar nerve or mental nerve in nine patients, and leptomeningeal seeding or intracranial metastasis to the trigeminal nerve root at the skull base in two patients. CONCLUSION: NCS without obvious odontogenic causes or trauma often signals systemic malignancy. It may be the first clue of occult malignancy.

Relationship Between the Quantity of Nerve Exposure During Bilateral Sagittal Split Osteotomy Surgery and Sensitive Recovery.

AIM AND OBJECTIVES: The purpose of this study was to evaluate how different exposures of the V3 nerves during orthognathic surgery impact neurosensory disturbances. METHODS: The study included 127 patients who underwent either bilateral sagittal split osteotomy (BSSO) or BSSO with maxillary le Fort 1. They were divided into 6 groups, identified by the quantity of V3 nerve exposure. All patients were examined in a pre-op period and again after 1, 3, 6 months post-op. The standardized tests used were to clarify the objective and subjective neurosensory status of the exposed nerve. Neurosensory evaluation included; a pin prick test, the 2 points discriminator, light touch, warm and cold tests, and blunt discrimination. They were all done bilaterally on the lower lip area. RESULTS: In only 2 patients the nerve was damaged during surgery and thus they were not included in this study. In 10.2% of patients there was no nerve exposure, 25.2% had longitudinal vestibular segment nerve exposed, 22.8% had the longitudinal upper-vestibular segment exposed, 20.5% had the longitudinal lower-vestibular segment exposed, 14.2% had the longitudinal upper-lower-vestibular segment exposed, and in 7.1% of patients the nerve was totally exposed. Given the estimated time of 1 month there was 100% recovery in patients whose nerve was unexposed. Considering the other patients, the authors had a variable number of patients who did not recover completely. CONCLUSION: The authors estimate a correlation between the recovery time and the quantity of the exposed nerve. There is a high incidence of neurosensory disturbance in the lower lip and chin after BSSO and intraoperative quantity of nerve exposure.

Effects of Superpulsed, Low-Level Laser Therapy on Neurosensory Recovery of the Inferior Alveolar Nerve.

OBJECTIVE: The purpose of this investigation was to evaluate the therapeutic efficacy of superpulsed, low-level laser therapy (SLLLT) on neurosensory recovery of the inferior alveolar nerve (IAN) after oral surgical injury. BACKGROUND DATA: A survey of the literature reveals the uncertainty of outcomes for the surgical management of IAN injury and the efficacy of low-level laser therapy in the treatment of IAN injury. METHODS: In this study, the authors report the results for SLLLT in 57 patients affected by paresthesia of the lip, chin, gingival, and buccal regions. Each patient was subjected to 10 laser treatments, once a week, with a GaAs diode laser. Clinical neurosensory tests (soft touch, 2-point discrimination, pin prick, thermal test) and the visual analogue scale were used before every treatment to evaluate the extent of neurosensory recovery. RESULTS: The authors' results demonstrate that 83.3% of the patients had a significant neurosensory recovery, as evident in the objective and subjective tests. CONCLUSION: The results reported in this study indicate that SLLLT has the potential to improve neurosensory recovery in patients with IAN paresthesia.