Novel design of miniplate for fixation of fractures at transition zone of parasymphysis-body region of mandible – A clinical randomised study

Fractures through the mandible at the level of the parasymphysis extending obliquely and traversing through the transitional zone to body region are relatively common. Therefore, a surgeon should have an appropriate understanding of the biomechanics of different plating techniques to fix these fractures. There is always a dilemma for the surgeon as to whether to fix these mandibular segments with one or two miniplates, and the presence of mental neurovascular bundle makes it more challenging. A study was planned in the Department of Oral and Maxillofacial Surgery to evaluate a novel twin-fork design of a miniplate used for fracture fixation at the transition zone of parasymphysis and body region of mandible after an in-vitro study of same design, and provided encouraging results. A total of 30 patients (10 patients in three groups each) were included in the study. All patients were evaluated preoperatively and postoperatively for operating time, ease of placement of miniplate, occlusion, reduction of fracture, neurosensory disturbances and infection. The novel design of twin-fork−shaped miniplate proved to be superior to the conventional miniplate in terms of neurosensory (Fisher exact test 17.40; p = 0.003) and functional outcome. There was statistically significant difference (χ² = 13.895, p = 0.031) in postoperative reduction of fracture at week 4, indicating superiority of the twin-fork miniplate among the other conventional designs. The study concludes that the use of newly designed twin-fork−shaped miniplate should be encouraged in the fractures of transitional zone of parasymphysis-body region involving mental neurovascular bundle.     

Exposure to formaldehyde and phenol during an anatomy dissecting course: sensitizing potency of formaldehyde in medical students

BACKGROUND: The sensitizing potency of formaldehyde and phenol during anatomy dissecting was investigated. The objective was to determine whether exposure induces specific IgE or IgG against formaldehyde-albumin or phenol-albumin. METHODS: In 27 medical students, specific IgE against formaldehyde-albumin by RAST plus ELISA and specific IgE against phenol-albumin by ELISA were assessed. In addition, specific IgG against formaldehyde-albumin was assessed in 23 students. Symptoms before and during dissecting were assessed, and indoor formaldehyde and phenol were measured. RESULTS: Mean indoor formaldehyde was 0.265 +/- 0.07 mg/m3, and mean indoor phenol was 4.65 +/- 2.96 mg/m3. Specific IgE/IgG against formaldehyde-albumin was not found at the beginning. Four students developed specific IgE against formaldehyde-albumin (RAST classes of > or =2.0), and all four also had specific IgE in the ELISA, but IgG against formaldehyde-albumin was not found. Specific IgE against phenol-albumin was not seen. Itch and paresthesia of the hands (P<0.00001), dizziness (P<0.008), burning eyes (P<0.01), headache, sneezing, epistaxis, gingival bleeding, oral or pharyngeal itch, and shortness of breath were experienced. CONCLUSIONS: Formaldehyde exposure during dissecting may induce specific IgE, but not IgG, against formaldehyde-albumin. Sensitization did not correlate with symptoms.     

Review of Risk Assessment of Major Anatomical Variations in Clinical Dentistry

Most of the studies of the mandible's anatomical variations have presented the authors' speculations, and only a limited number has provided evidence that demonstrated the actual complications injury to the variant structures caused. To our knowledge, no study has evaluated the risks associated with these variant anatomical structures' injury. We reviewed articles that described clinical cases of the injury to, and anatomical studies of, three anatomical variants of the mandible—the accessory mental, lingual, and retromolar foramina—with which dentists are relatively familiar and that are mentioned often in the context of implant and third molar surgeries, to describe risk assessment methods with which to evaluate potential complications preoperatively. Only a limited number of the clinical reports of injury to the mandible's accessory foramina were available. The potential severe complication of injury of the accessory mental foramen (AMF) is sensory disturbance of the lower lip. Risk of neurosensory disturbance of lower lip can be assessed by AMF/MF ratio and positional relations to the MF. Potential severe complication of injury of the lingual foramen is bleeding and hemorrhage in the oral cavity's floor. Risk of bleeding can be assessed by diameter and positional relation between the mental spine/mylohyoid line. A risk assessment of the retromolar foramen could not be made because of inadequate data. We hope the risk assessments suggested will encourage dentists to predict intraoperative/postoperative complications caused by damaging the mandible's accessory foramina. Clin. Anat. 32:672–677, 2019. © 2019 Wiley Periodicals, Inc.     

Triple Leads Programmed to Perform as Longitudinal Guarded Cathodes in Spinal Cord Stimulation: A Modeling Study

Objective: In spinal cord stimulation, neurosurgeons increasingly tend to implant dual leads. Dual leads (longitudinal bipole/tripole) provide medio‐lateral control over the recruited dorsal column (DC) area by steering the injected cathodal currents. However, the DC recruited area is suboptimal when dual aligned leads straddling the midline programmed as longitudinal guarded cathodes (+−+) are used instead of a single lead placed over the spinal cord midline with the same configuration. As a potential improvement, an additional third lead between the two aligned leads is modeled to maximize the medio‐lateral extent of the DCs at the low‐thoracic vertebral region (T10‐T12). Methods and Materials: The University of Twente Spinal Cord Stimulation software (UT‐SCS) is used in this modeling study. Longitudinal guarded cathodes were modeled on the low‐thoracic vertebral region (T10‐T12) using percutaneous triple lead configurations. The central lead was modeled over the spinal cord midline and the two lateral leads were modeled at several transverse distances to the midline lead. Medio‐lateral field steering was performed with the midline lead and the second lead on each side to achieve constant anodal current ratios and variable anodal current ratios. Results: Reducing the transverse lead separation resulted in increasing the depths and widths of the recruited DC area. The triple lead configuration with the least transverse separation had the largest DC recruited area and usage range. The maximum DC recruited area (in terms of both depth and width) was always found to be larger under variable anodal current ratio than constant anodal current ratio conditions. Conclusions: Triple leads programmed to perform as longitudinal guarded cathodes provide more postoperative flexibility than single and dual leads in covering a larger width of the low‐thoracic DCs. The transverse separation between the leads is a major determinant of the area and distribution of paresthesia.     

Recurrent Spontaneous Paresthesia in the Upper Limb Could Be Due to Migraine: A Case Series

Transient neurologic dysfunction is a characteristic feature of migraine. About 20% of migraineurs may experience various symptoms in the absence of any headache at one time or another. Visual auras are the most common auras of migraine, and migraine is considered as the most common cause of transient vision loss in young patients. Sensory auras are the second most common migrainous auras. However, the literature is silent for isolated sensory aura as a migraine equivalent. Herein we report 14 patients with recurrent episodic paresthesia in the limbs and other body parts. All patients fulfilled the diagnostic criteria of “typical aura without headache” of ICHD‐3β. All patients were subjected to various investigations to rule out secondary causes. Ten patients received antimigraine drugs and all showed a positive response to therapy. Recurrent spontaneous paresthesia is quite common in the general population and many patients remain undiagnosed. We speculate that a subset of patients might be related to migrainous sensory auras.     

原发性三叉神经痛伽玛治疗后面部感觉异常情况分 析简

目的分析伽玛刀治疗原发性三叉神经痛病人面部感觉异常发生率及其与疼痛缓解间的关系。方法回顾性分析45例接受伽玛刀治疗并有完整随访的原发性三叉神经痛病例资料,记录和分析疼痛控制效果、起效时间以及面部感觉异常等并发症发生情况。结果中位随访时间15个月（12～37个月）。术后初始疼痛缓解BNIⅠ级15例（33-3％）,Ⅱ级13例（28．9％）,Ⅲ级8例（17．8％）,Ⅳ级5例（11．1％）,Ⅴ级4例（8．9％）;伽玛刀治疗整体有效率为80％。至最后一次随访,复发6例（13.3％）,（初始疼痛缓解为BNII级3例,Ⅲ级3例）;平均复发时间11．7个月（5～18个月）。伽玛刀治疗后新发面部感觉异常17例（37．8％）,疼痛完全缓解者新出现面部感觉异常的比例明显高于部分缓解或疗效不佳者（P〈0．05）。结论伽玛刀是有效的三叉神经痛治疗方法．术后面部感觉异常发生可能与更好的疼痛缓解相关。     

Semmes-Weinstein单丝检测下颌骨矢状劈开截骨术后下牙槽神经功能的初步研究

目的:客观评价下颌失状劈开截骨术后下齿槽神经感觉障碍发生及自然恢复的发生率。方法:选择30例双侧下颌升支矢状截骨的患者在术前和术后1周、4周、2个月和6个月进行下齿槽神经感觉障碍的临床评价。30例患者均采用Semmes-Wei nst ei n单丝测试法。结果:术后7天感觉障碍发生率为100%。在所有检测区域,术后6个月的测量结果与术前最接近。6个月时20例患者感觉恢复术前水平。左右侧及性别间感觉障碍恢复优秀率的差异在各个随访时期均无统计学意义(P>O.05)。结论:BSSO术后早期感觉功能障碍较为普遍,然而在术后6个月,大多数患者的神经功能可达到自然恢复。     

Temporary paresthesia of the lower lip during traction of retained inferior premolar

Paresthesia of lower lip due to orthodontic treatment is a rare condition and little described in the literature. The aim of the present report is to describe the first case of lower lip paresthesia after traction of the lower second premolar. The patient reported the most paresthesia in the first week of traction, which improved progressively with time. Total recovery was only noted after 13 months.