Effects of streptomycin on the rat infraorbital nerve.

INTRODUCTION: It has been reported that streptomycin can have anti-neuralgic effects. However, the mode of action is unknown. This article was intended to investigate eventual neurolytic effects of streptomycin on peripheral nerves when applied topically. MATERIAL AND METHOD: The rat infraorbital nerve, used as the experimental model, was treated with 0.01 ml of streptomycin sulphate dissolved either in distilled water or in lidocaine via an infraorbital perineural injection. Saline was used in control animals. RESULTS: Cross-sections of the nerve, a week following treatment with streptomycin, revealed damaged axons with disintegration of both heavily and thinly myelinated fibres. Signs of regeneration were detected from the fourth postoperative week on. In control rats no damage was observed. CONCLUSION: Streptomycin can cause peripheral nerve damage when injected perineurally. These morphological changes may be responsible for anti-neuralgic effects of streptomycin.     

脂质体阿霉素对大鼠三叉神经形态与功能影响的实验研究

目的 :观察脂质体阿霉素对大鼠三叉神经形态与功能的影响。方法 :3 3g/L脂质体阿霉素直接注射于大鼠一侧眶下神经束 ,对侧以生理盐水对照。神经电生理检查给药后大鼠的二腹肌肌电的变化 ,光镜下观察实验侧三叉神经节细胞的形态学变化 ,透射电镜观察三叉神经节细胞的超微形态结构变化。结果 :神经电生理结果显示动物对针刺反应不敏感 ,并显示不同时间左右两侧潜伏期 (ms)及痛阈 (mA)的变化都有显著性差异 (P <0 .0 5 ) ;实验侧光镜下可见大量细胞皱缩 ,形态不规则 ,细胞周围出现空隙 ;电镜下可见胞质中出现不规则的电子致密物质 ,线粒体、高尔基体、粗面内质网、核膜、有髓神经纤维髓鞘和无髓神经纤维病理性改变。结论 :脂质体阿霉素注入神经干后 ,可以选择性破坏相应的节细胞 ,引起神经功能上的变化。     

Trigeminal neurosensory changes following acute and chronic paranasal sinusitis.

OBJECTIVE: The aim of this study was to document sensory changes in the supraorbital, infraorbital, and mental nerve distributions following acute and chronic maxillary and frontal sinusitis. METHOD AND MATERIALS: Seven patients with a total of 14 infected sinuses were included in the study. Neurosensory function was evaluated by measuring the electrical detection threshold for large myelinated nerve fibers and heat detection thresholds for the assessment of the thin unmyelinated nerve fibers. The sensory tests were conducted in the infraorbital, supraorbital, and mental dermatomes. Patient evaluation included clinical examination and computerized tomographic imaging of the sinuses. Sinusitis symptoms of 1 month or less were considered acute, and symptoms that persisted for more than 3 months were considered chronic. Detection thresholds in 8 healthy volunteers served as controls. RESULTS: Eight acute and 6 chronic sinusitis cases were diagnosed. Acute sinusitis produced bilateral large myelinated fiber hypersensitivity (electrical) relative to healthy controls, with no significant change in the thin unmyelinated nerve fiber detection threshold (thermal). Chronic sinusitis resulted in large myelinated fiber hyposensitivity and thin myelinated fiber bilateral hyposensitivity, as compared to healthy controls. CONCLUSIONS: This study concurs with previous studies in finding that early inflammatory neuritis can produce large myelinated nerve fiber hypersensitivity, while long-lasting processes, presumably accompanied with early nerve damage, may result in hyposensitivity.     

Investigation of infraorbital nerve injury following zygomaticomaxillary complex fractures

Summary The aim of this study was to investigate the severity of infraorbital nerve injury following zygomaticomaxillary complex fractures and to estimate the treatment methods facilitating its functional recovery. A total of 478 patients with unilateral zygomaticomaxillary complex fractures were treated. Infraorbital nerve sensory disturbances were diagnosed in 64·4% of the patients. Injury of the infraorbital nerve was expressed as asymmetry index, which was calculated as a ratio between the affected side and the intact side electric pain detection thresholds at the innervation zone skin before treatment and 14 days, 1, 3, 6 and 12 months postoperatively. A mean asymmetry index of 0·6 ± 0·03 and 1·9 ± 0·5 was registered for 57 (11·9%) patients with hyperalgesia and for 251 (52·5%) patients with hypoalgesia, respectively. As a result of retrospective analysis of infraorbital nerve sensory disturbances and its functional recovery, infraorbital nerve injury severity was classified as mild, moderate and severe. It was found that the dynamics and outcome of the functional infraorbital nerve recovery depend on the severity of the injury and the presence of infraorbital canal damage. Function was completely recovered within 3 months after treatment in cases with mild nerve injury. In moderate cases, complete recovery was seen within 6 months and in 34·6% of the severe cases, within a 12‐month period after treatment when infraorbital nerve decompression was performed according to the stated indication. Treatment based on infraorbital nerve injury classification offers a better prognosis for complete recovery of the infraorbital nerve function.     

Quantitation of nerve fibres in the primary and permanent canine and incisor teeth in man.

Myelinated and unmyelinated nerve fibres were counted and myelinated axons were measured in juxta-apical cross-sections of human primary and permanent canines and incisors. Fully-developed human primary canines had significantly more myelinated axons than permanent canines, but the number of unmyelinated axons was similar. Permanent incisors had significantly more myelinated nerve fibres entering the apex than did primary incisors, but the number of unmyelinated nerve fibres was similar. Primary canines and incisors lost nerve fibres early during resorption; evidence of degenerating myelinated axons was scant. A significant linear correlation existed between numbers of myelinated and unmyelinated axons for primary incisors and canines. The myelinated axon circumference was similar for primary and permanent teeth. Permanent teeth tended to have smaller groups of unmyelinated axons.     

70例颧上颌复合体骨折类型与眶下神经损伤的相关分析

目的 比较不同类型颧上颌复合体（zygomaticomaxillary complex,ZMC）骨折后眶下神经的损伤情况。方法 参照经典Zingg分类法,对2015年收治的70例单侧ZMC骨折进行分类,并测定其患侧与健侧眶下神经支配区皮肤的痛阈及两点辨别觉。利用不对称指数（asymmetry index,AI）对眶下神经损伤情况进行比较。应用SPSS19.0软件包对数据进行统计学分析。结果 70例ZMC骨折患者患侧眶下神经支配区均有不同程度感觉异常。对痛阈的测定结果显示,不同骨折类型间眶下神经损伤程度存在显著差异（P<0.05）;两点辨别觉测定结果显示,B型与C型较A型骨折神经损伤程度更严重（P<0.05）,B型与C型骨折间神经损伤无显著差异。结论 ZMC骨折容易引起眶下神经损伤, B型骨折患者神经损伤情况最重, A型骨折神经损伤最轻。     

Innervation of human periodontium I. Classification of periodontal receptors

A bstract — The neural tissue in human periodontium is associated with the terminal part of a norve trunk from which myelinated nerve fibres leave and in some instances divide into three or more nerve fibres.
Encapsulated myelinated nerve fibres lose their myelin sheaths and encircle the adjacent myelinated nerve fibres to form compound meehanoreceptors approximately 35 × 45 μm. Simple mechanoreceptors of approximately 10 × 10 μm consisted of single myelinated nerve fibres surrounded by cell bodies and terminated as encapsulated unmyelinated nerve fibres. A cluster of compound mechanoreceptors formed a complex approximately 100times 150 μm.
An arterial system appeared to supply nutrition for the compound receptors, whilst an arcade of veins surrounded the neural complex.     

Effects of glycerol on the rat infraorbital nerve: an experimental study

Glycerol was injected into the infraorbital canal of 12 rats to determine neurolytic effects on the peripheral trigeminal nerve. Saline and 90% ethanol were injected in control animals. One week after the injection, histopathological changes were noted in both glycerol and alcohol groups. In the former group, axonolysis and demyelination were restricted to the outer zone of the nerve bundles. Centrally located axons remained undamaged. A total destruction of all axons was found in the alcohol group. Four weeks after the injection in the glycerol group, small sized axons with thin myelin replaced damaged axons at the periphery of the bundle. No signs of regeneration were noted in the alcohol group. A possible mode of action of glycerol injected at the peripheral trigeminal nerve in relieving trigeminal neuralgia is described.     

眶下孔周围注射滑石粉制作新型大鼠三叉神经痛动物模型的实验研究

目的: 应用滑石粉悬液进行眶下孔周围注射,建立一种新型大鼠三叉神经痛（trigeminal neuralgia,TN）动物模型。方法: 选取Wistar雄性大鼠30只,随机分为2组,一组在眶下神经孔周围注射30%滑石粉混悬液0.3 mL,另一组注射同等剂量的生理盐水,于术前3 d、术后3 d及术后1、2、3、4、6、8、12周分别进行行为学观察,Von Frey纤维测定大鼠机械性刺激反应阈值,利用方差分析对机械刺激阈值进行统计学分析。于术后3 d及术后4、8、12周取眶下孔周围组织作组织病理学观察,应用免疫组织化学的方法检测眶下区组织肿瘤坏死因子α(TNF-α)、白细胞介素1β(IL-1β)的表达,采用SPSS16.0软件包对各检测值进行分组t检验。结果: 实验组大鼠术后3 d眶下神经支配区域机械痛反应阈值与术前及对照组相比显著降低（P<0.01),大鼠易激惹,具有搔抓面部或攻击行为。直到术后12周,机械痛阈值仍然显著低于对照组。实验组术后3 d组织病理学观察主要呈炎症表现,炎性因子表达减少;术后1周炎症更剧烈,炎性因子表达。术后4周,局部出现炎性肉芽组织增生,炎性因子表达最高;4~12周炎性反应逐渐减轻,炎性因子表达逐渐减少,局部瘢痕形成并逐渐加重,可见瘢痕压迫眶下神经。结论: 眶下孔周围注射滑石粉悬液可以建立稳定的TN动物模型,该造模方法简单易行,为进一步研究TN发病机制和模拟临床治疗提供了一种可靠、有效的动物模型。     

Ultrastructure and degeneration analysis of the nerve fibres of the tooth pulp in the cat

An attempt was made to distinguish somatic sensory nerve fibres from autonomic postganglionic sympathetic nerves in tooth pulp by secondary degeneration. Pulps were compared after transection of the inferior alveolar nerve, after extirpation of the superior cervical sympathetic ganglion and after both operations performed at the same time (total neural isolation). About 15 per cent of the nerves in normal feline pulps were myelinated and about 85 per cent unmyelinated. Only 1.5 per cent contained granular vesicles 30–50 nm or 80–120 nm in diameter. After transection of the alveolar nerve, all myelinated as well as some unmyelinated fibres degenerated. Degenerated fibres contained no vesicles. After extirpation of the ganglion, only a few degenerating unmyelinated fibres were observed; some contained 80–100 nm diameter granular vesicles. Two months after total neural isolation, the pulp contained no nerve fibres.     

Innervation of the temporomandibular joint

A bstract — The human temporomandibular joint in transverse and longitudinal section was found to have two types of mechanoreceptors. One of capsular form approximately 40 times 200 μm innervated by myelinated nerve fibres 8 μm in diameter and the other corresponding to the Golgi tendon organ was innervated by myelinated nerve fibres 15 μm in diameter which on entering the tendon organ lost their myelin sheaths.     

Nerve growth factor injected systemically improves the recovery of the inferior alveolar nerve in a rabbit model of mandibular distraction osteogenesis

Our aim was to find out if nerve growth factor (NGF) injected systemically could improve the recovery of the inferior alveolar nerve in a rabbit model of mandibular distraction osteogenesis. We used 48 New Zealand white rabbits that were treated with bilateral distraction osteogenesis at a rate of 0.5 mm/12 h for 10 days. Immediately postoperatively, NGF or sodium chloride 0.6 μg/day was injected intramuscularly for 20 days. At the end of distraction and after consolidation times of 1, 2, and 4 weeks, the inferior alveolar nerves were evaluated histologically and histomorphometrically. Histologically, at 2 and 4 weeks there was less myelin debris, and more regenerating axons were present, in the NGF than the control groups. The density of myelinated axons was significantly greater in groups with NGF than controls at 2 and 4 weeks (p < 0.05). NGF given systemically can accelerate the recovery of the inferior alveolar nerve in rabbits after mandibular distraction osteogenesis, and is a promising treatment option for neurological complications of mandibular distraction osteogenesis.     

Cutaneous distribution of infraorbital nerve

The aim of this study is to elucidate precisely the cutaneous distribution of the infraorbital nerve. Ten hemifaces of five Korean adult cadavers (2 males and 3 females) were subjected to the dissection. The cutaneous branches of the infraorbital nerve were distributed over the infraorbital area, which bounds on superiorly the lower eyelid margin, inferiorly the horizontal line crossing the mouth corners, medially 0.5 cm to midline, and laterally 2 cm lateral to the temporal canthus of the eyes. The infraorbital nerve had 19.5 branches (range, 15-24 branches). The mean area supplied by the infraorbital nerve was 25.8 cm2 (range, 24.0-28.2 cm2). The mean area of the superior labial branch was 13.1 cm2 (range, 11.2-14.3 cm2) and broader than either the 7.5 cm2 (range, 6.6-8.8 cm2) of the lower palpebral branch or the 7.6 cm2 (range, 6.7-9.3 cm2) of the external nasal branch. The external nasal branch was overlapped with the lower palpebral and superior labial branch, but the last two branches do not overlap each other. The nonoverlapped branch of the infraorbital nerve exhibits a restricted anesthesia, but the overlapped branch sustains sensory perception to some extent when being damaged.     

Regional anesthesia for cleft lip repair: a preliminary study.

OBJECTIVE: To assess whether local anesthetic blockade of the infraorbital nerve may allow for cleft lip repair to be performed under regional anesthesia. METHOD: Twenty patients above 12 years of age with cleft lip (7 females and 13 males) were enrolled. Careful preoperative counseling was given. Bilateral infraorbital block was performed (extraoral approach) with 10 mL of equal volumes of 2% lidocaine with 1:200,000 adrenaline and 0.5% bupivacaine. The point of entry was the intersection of a vertical line through the pupil of the eye (in the neutral position) and a horizontal line through the ala of the nose. The needle was directed medially and cephalad until the infraorbital foramina was reached and 2 mL was injected. Through the same point of entry, but directed medially (toward the ala), 1 mL was injected followed by a 2-mL injection caudally and medially (into the lip). RESULTS: The block was successful in all patients without complication. The surgery was uneventful, lasting between 45 and 60 minutes. The postoperative duration of analgesia was between 6 and 24 hours (mean 16.5 +/- 5.10 SD). CONCLUSIONS: The nerve supply of the cleft lip, our modification of the block, and possible problems with this technique are discussed. This study confirms the utility of this block for postoperative analgesia. Further studies are required to apply this innovative, safe, and economical modification of anesthesia for cleft lip surgery.     

The epithelial proprial relations of Meissner''s corpuscles in buccal mucosa. An electron microscopic study

A bstract — Meissner's corpuscles were seen in specimens obtained from the buccal mucosa of three patients. The corpuscles arose mainly from myelinated nerve fibres although some unmyelinated fibres were involved. The myelin sheath terminated where the fibres entered the capsules. Axons were invested by lamella cell processes and terminated digitately in desmosome-like contacts with one another and the basal lamina of the basal epithelial cells. The corpuscles were encapsulated by collagen fibres and the cell processes of fibroblasts.     

Branching patterns of the infraorbital nerve and topography within the infraorbital space

The infraorbital nerve (ION) is the terminal branch of the maxillary nerve; it supplies the skin and mucous membranes of the middle portion of the face. This nerve is vulnerable to injury during surgical procedures of the middle face. Severe pain and loss of sense are noted in patients whose infraorbital nerve is damaged. In the study presented here, we investigated the branching pattern and topography of the ION, about which little is currently known, by dissecting 43 hemifaces of Korean cadavers. In most cases, the infraorbital artery was located in the middle (73.8%) and superficial to the ION bundle (73.8%) at its exit from the infraorbital canal. The ION produced four main branches, the inferior palpebral, internal nasal, external nasal, and superior labial branches. The superior labial branch was the largest branch of the ION produced the most sub-branches. These sub-branches were divided into the medial and lateral branches depending upon the area that they supplied. We were able to classify four types of branching pattern of the external and internal nasal branch and the medial and lateral sub-branches of the superior labial branch of the ION at the site of their emergence through the infraorbital foramen (types I-IV). Type I, where all four branches are separated occurred the most frequently (42.1%). These findings will help to preserve the ION while performing certain types of maxillofacial surgery, such as removal of a tumor from the upper jaw and fracture of the upper jaw.     

面中骨折术后眶下神经损伤恢复的临床观察

目的：观察面中骨折后眶下神经损伤的恢复状况。方法：对28例面中骨折后眶下神经损伤的患者，术后通过患者自述、针剌检测、两点辨别觉及直流感应电测仪测定眶下神经的恢复状况及恢复时间。采用SPSS12．0软件包对数据进行t检验。结果：25例患者的眶下神经损伤得到恢复，神经恢复时间在4-6个月，平均25周：3例患者未能恢复．成为永久性损伤。未发现慢性神经性疼痛患者。结论：大部分骨折后眶下神经损伤是暂时的、可恢复的，极少数为永久性损伤。对伤后6个月神经功能仍未恢复的患者，可考虑行眶下神经减压术。     

Efficacy of epinephrine‐free articaine compared to articaine with epinephrine (1:100 000) for maxillary infiltration,a randomised clinical trial

The selection of local anaesthetic in dental practice is essential to the patient′s comfort and the success of the treatment. Many patients prefer anaesthesia even for short treatments. Articaine is a local anaesthetic commonly used for dental practice. The duration of the effect of articaine on the nerve fibres is not yet precisely reported. This study was aimed to evaluate the clinical efficacy of 4% articaine with and without epinephrine in treatment of occlusal caries. Thirty healthy patients were included in this randomised double‐blind study. Each subject received 4% articaine with and without epinephrine (1:100 000). Maxillary infiltration was used for occlusal caries of the maxillary premolars on right and left sides. Quantitative sensory testing (QST) was performed in the innervation area of the infraorbital nerve, and pulp vitality test was performed on restoration‐free canines. Duration of anaesthesia was longer when articaine with epinephrine was used. Articaine without epinephrine showed faster recovery of sensory blockade compared to articaine with epinephrine. The epinephrine‐containing agent, when compared to the plain articaine solution, showed significantly stronger and longer anaesthetic efficacy on the soft tissue by all parameters of QST. Articaine with epinephrine caused a more reliable pulpal analgesia. A pain‐free treatment of the soft tissue up to 15 minutes can be performed under the vasoconstrictor‐free anaesthetic without causing long‐lasting numbness. Epinephrine‐containing articaine delivers a longer, more effective anaesthesia and is preferable for caries treatments and longer invasive treatments of the soft tissue.     

A comparison of the local anesthetic efficacy of the extraoral versus the intraoral infraorbital nerve block

BackgroundThe efficacy of the extraoral infraorbital nerve block has not been studied sufficiently to ensure its appropriate clinical use. To compare the local anesthetic efficacy of the extraoral versus the intraoral infraorbital nerve block, the authors conducted a prospective, randomized crossover study.MethodsForty adult participants randomly received extraoral infraorbital nerve blocks of 1.8 milliliters of 2 percent lidocaine with 1:100,000 epinephrine at one appointment and intraoral infraorbital nerve blocks of 1.8 mL of 2 percent lidocaine with 1:100,000 epinephrine at another appointment in a crossover design. After administering the injections, the authors used an electric pulp tester to assess the maxillary central and lateral incisors, canine, premolars and first molar for pulpal anesthesia in four-minute cycles for 60 minutes. They considered anesthesia to be successful when the participant had no response to two consecutive 80 readings (the maximum output) with the electric pulp tester.ConclusionsThe authors found that the extraoral and intraoral infraorbital nerve blocks were ineffective in providing profound pulpal anesthesia of the maxillary central incisor (15 percent success rate) and lateral incisor (22 percent success rate). The pulpal anesthesia success rate was 92 percent for the canine for both types of nerve blocks, 80 to 90 percent for first and second premolars and 65 to 70 percent for the first molar, with no significant differences (P < .05) between the two nerve blocks. Pulpal anesthesia did not last for an hour in any of the teeth. Needle insertion pain and postoperative sequelae were more common after the extraoral infraorbital nerve block was administered.Clinical ImplicationsBoth nerve blocks would be ineffective in the central and lateral incisors. Both nerve blocks would be somewhat successful in the canine and premolars but not in the first molar.