Clinical anatomy of the superior alveolar nerves

Unilateral dissections were carried out on 19 human cadaver heads to demonstrate the superior alveolar nerves and vessels. The positions of foramina on the infratemporal surface of the maxilla were noted and, after decalcification of the bone, a transillumination technique was used to display the nerves and vessels in situ. Considerable variation was found in the origin, path and branches of anterior superior alveolar nerves. A middle superior alveolar nerve was found in seven dissections. The clinical importance of these findings is discussed in relation to local analgesia and surgery of the maxillary antrum.     

New anatomic intraoral reference for the anesthetic blocking of the anterior and middle maxillary alveolar nerves (infraorbital block)

The superior lateral labial frenum is proposed as a new anatomic reference for the intraoral blocking technique of anesthesia of the anterior and middle superior alveolar nerves (infraorbital). The main advantage of this technique is the constancy of the reference point, independent of the presence or absence of teeth, which other techniques do not offer.     

(iii) Entrapment neuropathies of the foot and ankle

Any of the 5 nerves supplying the foot and ankle (tibial, superficial & deep peroneal, sural, saphenous) can suffer compression neuropathy. The diagnosis is usually made clinically, supported by imaging and electrodiagnostic studies. Treatment is conservative or surgical. The known nerve entrapments about the foot and ankle are presented with a discussion of their aetiology, clinical findings and treatment options.     

Myelinated fibre diameters of human inferior alveolar nerves

These were examined in a series of 36 human post-mortem specimens. One unimodal, 32 bimodal and 1 trimodal diameter curves were demonstrated; group analysis of all samples gave a bimodal curve with 2-4 and 8-9 microns peaks.     

Dysesthesia of the lingual and inferior alveolar nerves following third molar surgery

A summary of the responses to the questions in a national survey pertaining to nerve dysfunction and the standard of care for such dysfunction is presented. The lingual nerve had a functional alteration rate of one in every 1756 patients, and about 13% of these alterations persisted for more than a year. The inferior alveolar nerve had a functional alteration rate of one in every 241 patients, with about 3.5% of these alterations persisting for more than a year. The standard of care did not include microsurgical or other surgical correction.     

Observations on the exploration and external neurolysis of injured inferior alveolar nerves

The inferior alveolar nerve is sometimes injured during mandibular surgery, resulting in altered sensibility. Incomplete recovery may be the result of nerve entrapment by scar tissue. Twelve patients underwent external neurolysis of the inferior alveolar nerve following prolonged sensory impairment secondary to mandibular surgery. The mean time to external neurolysis was 14 months (range 12-24 months). Five patients demonstrated improvement in sensibility, two patients returning to normal sensation. No patient had a worsening of symptoms. The results demonstrate that external neurolysis can be a useful step during surgical exploration in carefully selected patients.     

Anaesthesia of the inferior alveolar and lingual nerves following subcondylar fractures of the mandible

A retrospective chart review of 387 patients with condylar and subcondylar fractures revealed 2 cases of inferior alveolar nerve (IAN) and lingual nerve (LN) anaesthesia following the subcondylar fracture. Only 5 cases have been reported previously. The mechanism of action remains unknown but a review of the literature and an analysis of 120 dry human skulls supported the hypothesis that compression of the mandibular nerve at a high level, close to the foramen ovale, could cause anaesthesia. This complication is rare, because it requires compression at a particular angle. The antero-median angulation of the condyle must be close to the foramen ovale, and the fracture must be a unilaterally displaced fracture. The presence of an enlarged lateral pterygoid plate appeared to enhance the risk of compression. The IAN and LN anaesthesia could be resolved after open reduction of the fracture and IAN and LN anaesthesia constitute a strict indication for an early open fracture reduction.     

Assessment of recovery from injury to inferior alveolar and mental nerves

Thirty-four patients had surgery near but not transecting either the inferior alveolar nerve or mental nerve. Thermal tests revealed that between 62% and 81% of the nerves that were evaluated had sensory deficits. Sixty-seven percent of patients had abnormal intraoral and extraoral responses to fine tactile testing. The least discriminative test was two-point contact. A smaller percentage (14% to 23%) were hyperpathic to heat stimuli, and a few (5% to 15%) had completely normal thermal and tactile sensation. A high percentage (43% to 71%) of patients elected to have corrective nerve surgery.     

神经生长因子对下齿槽神经再生影响的实验研究

目的 探讨外源性神经生长因子（ｎｅｒｖｅ ｇｒｏｗｔｈ ｆａｃｔｏｒ,ＮＧＦ）对成年大白兔下齿槽神经再生的影响。方法 选用２４只成年日本大耳白兔,在双侧下齿槽神经各造成８ｍｍ缺损,神经近远端用硅胶管桥接,右侧硅小室 内注入外源性ＮＧＦ 作实验侧,左侧注入生理盐水为对照侧。对实验侧和对照侧的再生有髓神经纤维数目、传导速度、纤维横断面积和髓鞘厚度作相应比较。结果 ①ＮＧＦ能使有髓神经纤维数目明显增加;     

Sensory impairment of the lingual and inferior alveolar nerves following removal of impacted mandibular third molars

In a prospective study 1,106 impacted mandibular third molars were removed from 687 patients. Clinical, radiographic, and surgical factors were recorded. Postoperatively, we examined the modalities of common sensation in order to assess sensory deficit. The patients were followed up, until complete restitution occurred, or, if the sensibility failed to recover, for at least 6 months. A total of 3.6% of the operated sides demonstrated impairment of labial sensation, and 2.1% of lingual sensation. The vast majority of these disturbances subsided completely during the follow-up period. The incidence of persisting sensory diminution after 6 months was 0.91% for the inferior alveolar, and 0.37% for the lingual nerve. However, the degree of the persisting deficit was slight in most instances. The relationship between the recorded factors and the alteration of sensation was analysed by using the chi2 test. For the inferior alveolar nerve we found the patient's age, the development of the roots, the degree of impaction, and the radiographic position of the nerve canal to be significantly correlated to sensory deficit, as well as the surgical procedures in the depth of the socket and the intraoperative opening of the mandibular canal. As far as the lingual nerve is concerned, general anaesthesia and the individual operator were the main factors predictive of nerve damage.     

Quantitative thermosensory testing of the lingual and inferior alveolar nerves in health and after iatrogenic injury

Quantitative testing of the sensory thermal thresholds testing was applied at sites innervated by the third division of the trigeminal nerve in 20 patients with no reported sensory impairment and in 20 subjects with iatrogenic nerve injuries after third molar surgery. In the control group sensitivity to cooling was significantly greater than the sensitivity to warming at all sites. The labial mucosa innervated by the inferior alveolar nerve was significantly more sensitive to thermal changes than either the mental region or the lingual mucosa. At sites supplied by nerves that had been injured, there were raised thresholds to both warming and cooling compared with the control group, and with uninjured contralateral sites. The results indicate that this test can identify iatrogenic lingual and inferior alveolar nerve injury with reference to a control group but because of spatial variation selection of control sites for comparison should be done cautiously.     

State of lower alveolar and mental nerves by mandible fractures healing under transbone osteosynthesis

Fracture of mandibular body at the level of P3-P4 with symphysis rupture was modeled, reposition and transosseous osteosynthesis with a specially developed device were performed under anesthesia in the operating room in 17 adult mongrel dogs in order to specify the pathogenesis and the dynamics of injury and jaw nerve regeneration. It has been established, that the arrangement of the neurovascular bundle in medullary canal predetermines the development of acute and chronic compression-and-ischemic neuropathy even if accurate reposition of bone fragments takes place. The histological signs of nerve fiber regeneration, the loss of the quantity of myelin-free nerve conductors and the retrograde spreading of degenerative changes in myelinized nerve conductors, including regenerating ones, have been found beginning from 4 weeks after injury. It has been concluded, that spontaneous nerve regeneration in case of mandibular fractures should be actively supported by neuroprotective, anti-edematous and anti-inflammatory therapy.     

The myelinated fibre content of human inferior alveolar nerves from dentate and edentulous subjects

A study of the myelinated fibre content of human inferior alveolar nerves was undertaken on groups of nine dentate and nine edentulous subjects. Results show that after all the mandibular teeth have been removed, the myelinated fibre count is reduced but there is no selective loss of any specific-diameter group of fibres.