Bifurcation of external jugular vein: an anatomical variation during neck dissection

Background

The pattern of venous drainage of head and neck involves single external jugular vein bilaterally.

Methods and results

We report a case of bifurcation of the external jugular vein observed during a neck dissection procedure.

Conclusions

Anatomical variations in drainage pattern of superficial veins of the head and neck are important for head and neck surgeries including for anastomosis during free tissue transfer for head and neck reconstruction.

     

Lingual accessory mental foramen: a report of an extremely rare anatomical variation

The presence of accessory foramina and canals in the mandible is frequently overlooked in clinical procedures. It is important to note that these anatomical variations may only be pre-surgically detected on imaging exams, and such detection may directly influence therapeutic success. We describe a previously unreported case of accessory mental foramen located in the lingual cortical bone of the mandible.     

Anatomical study of accessory nerve innervation relating to functional neck dissection.

PURPOSE: The present study sought to clarify correlations of accessory nerve innervation in the neck region and innervation of the sternocleidomastoid and trapezius muscles with postoperative dysfunction after functional neck dissection by macroscopic observation. MATERIALS AND METHODS: The materials used in this study were 35 cadavers provided for anatomical practice to the Department of Anatomy, Tokyo Dental College. The accessory nerve was identified at the anterior margin of the trapezius muscle, and its innervation in the posterior triangle of the neck was examined in detail. RESULTS: The superficial cervical vein vascularizes the anterior margin of the trapezius muscle near an area where the main trunk of the accessory nerve innervates the trapezius muscle. The results showed 3 types of accessory nerve innervation of the sternocleidomastoid muscle: Type A, the not penetrating type; Type B, the partially penetrating type; and Type C, the completely penetrating type. In addition, 5 types of innervation of the trapezius muscle by the main trunk and branches of the accessory nerve were apparent, with the number of branches innervating the muscle ranging from 0 to 4. CONCLUSIONS: Dysfunction after functional neck dissection can thus be avoided by paying attention to not only the main trunk of the accessory nerve, but also the branches. Moreover, when identifying accessory nerve innervation of the trapezius muscle, the superficial cervical vein may offer a useful surgical landmark.     

High division of the spinal accessory nerve and communication with a C2 branch of the cervical plexus: a previously unreported anatomical variant

Anatomical variations of the spinal accessory nerve are well known. We describe a previously unreported variant in which the nerve divided high in level II after crossing the internal jugular vein and before entering the sternomastoid muscle. Both branches were joined by a communication from the C2 cervical root. We discuss the clinical implications of this finding.     

功能性根治性颈淋巴清扫术中的副神经手术解剖及保留方法

目的：探讨功能性根治性颈淋巴结清扫术中的副神经解剖及保留方法。对33例口腔癌患者术前颈部淋巴结检查阴性者行三保留功能性根治性颈清扫术。介绍副神经的寻找及保留方法，记录副神经与周围结构关系、手术时间及术后淋巴结病理检查结果等。结果：82％（27／33）副神经穿过胸锁乳突肌，18％（6／33）在胸锁乳突肌深面行走；85％（28／33）副神经和颈神经根间存在吻合交通支；副神经在耳大神经出胸锁乳突肌后缘中点上方2cm范围内出该肌；70％（23／33）副神经在进入斜方肌前约2－3cm基本与该肌前缘平行下行后进入该肌；副神经游离；解剖时间约20－30min；术后病理证实27％（9／33）病例颈淋巴结转移。结论：在胸锁乳突肌前缘上份深面及后缘中点上易于寻找副神经，耳大神经出胸锁乳突肌后缘中点是协助寻找副神经的重要解剖标志。     

Injury to the long thoracic nerve as a complication of neck dissection: a case report

Injury to nerves by dissection of the neck is well recognised. A case report of injury to the long thoracic nerve follows, which has not been previously described.     

Clinical and anatomical aspects of possible mylohyoid nerve injury during genioplasties

Damage to the cutaneous branch of the mylohyoid nerve (CBMN) during genioplasties is possible but rare. The aim of this cadaveric study was to demonstrate possible mechanisms of injuring the CBMN during genioplasties. Mandibulotomy access was used to carry out sublingual and lateral cervical dissections on 10 formalinized cadavers with a mean age of 65 years. The length of the mylohyoid nerve was measured at three sections on the mandible. The posterior section of the mylohyoid nerve was 8.7 ± 0.5 mm; the middle section was 14.5 ± 0.9 mm and the anterior section was 15.6 ± 1.2 mm in length. The submental skin island of 7 specimens had unilateral innervation by the CBMN. The bilateral innervation pattern was detected in 3 of the specimens. Damage to the sensory and the motor branches of the mylohyoid nerve can occur during genioplasties by transaction of the soft tissue pedicle attached to the mental spine and inferior border of the symphis. Surgeons should pay attention during dissection and osteotomy of the chin to avoid complications of the mylohyoid nerve and its branches.     

Facial nerve injury during surgery of the temporomandibular joint: a comparison of two dissection techniques

Changing the dissection technique for gaining access to the temporomandibular joint decreased the incidence of facial nerve injury from 25% to 1.7%. This decrease can be attributed to the elimination of both development of a skin flap and dissection of tissue overlying the lateral capsule. Normal anatomic variation in the distribution of facial nerve branches may relate to the incidence of clinically apparent injury.     

Rare anatomical variant of the spinal accessory nerve: case report and comprehensive review

Historical studies of the anatomy of the spinal accessory nerve (SAN) have reported conflicting results regarding its relationship with the internal jugular vein (IJV). A literature review was undertaken to establish the prevalence of anatomical variations of the SAN encountered during routine neck dissection surgery, in order to increase awareness and reduce morbidity associated with iatrogenic SAN injury. The published literature was analysed by qualitative synthesis and nine articles were yielded following application of the inclusion and exclusion criteria. Incidences of the SAN lateral to the IJV and medial to the IJV ranged from 39.8% to 96.6%, and 2.6% to 57.4%, respectively. Five of the studies reported incidences of the SAN traversing the IJV, which occurred in 0.9% to 2.8% of cases. One study reported an isolated variant of the SAN dividing around the IJV, with a prevalence of 0.5%. We present a case report demonstrating the rare variant of the SAN traversing the IJV. Preoperative identification of rare anatomical association of the SAN and IJV may reduce perioperative injury to vital structures during neck dissection.     

Stress fracture of the clavicle. A rare late complication of radical neck dissection

Stress fracture is a rarely reported late complication of radical neck dissection. The condition should be recognised as its clinical and radiological differentiation from avascular necrosis or bony metastasis may be difficult.     

A simple method of identifying the spinal accessory nerve in modified radical neck dissection: anatomic study and clinical implications for resident training

Purpose

The major complication of neck dissection and surgery at the posterior triangle of the neck is the shoulder syndrome, which results from spinal accessory nerve injury. Erb’s point (the great auricular nerve) and the point where the spinal accessory nerve enters the trapezius muscle are used to identify the spinal accessory nerve in the posterior nerve triangle.

Materials and methods

Measurements were made during unilateral neck dissections in 30 patients to identify the relationship between the spinal accessory nerve and great auricular nerve and the distance between the entrance of the accessory nerve in the trapezious and clavicle.

Results

The distance between the spinal accessory nerve and Erb’s point was ranging from 0 to 3.8 cm (mean 1.53 cm). The distance between the spinal accessory nerve entering the trapezious muscle and the clavicle was between 2.5 and 7.3 cm (mean 4.8 cm).

Conclusions

Since the great auricular nerve (Erb’s point) represents a constantly identifiable landmark, it allows simple and reliable identification of the course of the spinal accessory nerve. Also useful, but of secondary importance in our opinion, is identifying the nerve at the point where it enters the trapezius muscle.     

Anomalies of the common carotid artery: A rare complication of radical neck dissection

Anatomical variants of the common carotid artery are rarely reported. Two different congenital anomalies of the common carotid artery, encountered during radical neck dissection, are documented and their surgical significance discussed.     

A rare variation in the course of the inferior alveolar nerve

Extra-canalicular variations of the inferior alveolar nerve are exceedingly rare and unreported. The authors report an unusual presentation of the inferior alveolar nerve perforating the ramus of the mandible with a very short intra-bony course and exiting laterally in a 20 year old indian female diagnosed with hemifacial microsomia. There was concomitant absence of the ipsilateral inferior alveolar canal and mental foramen. Variations in nerve architecture like these are of importance to clinicians who deal with surgery of the facial skeleton.     

Use of N-butyl-2-cyanoacrylate tissue glue in thoracic duct injury during neck dissection surgery

Although thoracic duct injury is an uncommon complication of neck dissection, it can have a significant physiological and immunological impact on the patient's recovery as well as having more serious effects. We report a novel technique of using cyanoacrylate tissue glue for managing thoracic duct damage when this is noted at the time of neck dissection surgery.We have used this technique in four patients with no post-operative chyle leak or added complications.     

Actinomycosis as a rare complication of orthognathic surgery

Modern orthognathic surgery is said to be clean contaminated due to the intraoral means of access. Complications after orthognathic surgery, a common operation, occur about 10% of the time. Actinomycosis, a rare specific infection, plays a negligible role. Diagnostically, it should be differentiated from other infections that occur a long time after the operation. Three cases of actinomycosis that occurred after orthognathic surgery were observed, and therapeutic measurements are described case by case.     

High output chyle leak after neck surgery: the role of video-assisted thoracoscopic surgery

Injury to the thoracic duct leading to formation of a chylous fistula is an infrequent but serious complication of major neck surgery that can result in a prolonged stay in hospital, and may lead to fluid, electrolyte, protein, and immune disturbances. Healing can also be impaired. We describe a case where an excessive chylous leak also contributed to the failure of two free flaps in the same patient, and we make recommendations regarding management of patients with free tissue transfer where this complication arises.     

The trigeminal nerve. Part IV: the mandibular division

The mandibular or third division of the trigeminal nerve is the largest of the three divisions. It is considered a mixed nerve. That is, like the ophthalmic and maxillary divisions, the mandibular conveys afferent fibers. But unlike the former two divisions, the mandibular also contains motor or efferent fibers to the muscles of mastication, the mylohyoid and anterior digastric muscles, and the tensor veli palatini and tensor tympani muscles. So intimately associated with dentistry, the mandibular nerve has also been termed the dental nerve by anatomists in the past. This extensive and complicated division of the trigeminal nerve can cause confusion to both patient and doctor. Pain is often referred within its branches and even into other trigeminal divisions, chiefly the maxillary. This fourth and last article about the trigeminal nerve will present in detail the mandibular division.     

The trigeminal nerve. Part II: the ophthalmic division

The ophthalmic, or first division (V1) of the trigeminal nerve, is the smallest of the three divisions and is purely sensory or afferent in function. It supplies sensory branches to the ciliary body, the cornea, and the iris; to the lacrimal gland and conjunctiva; to portions of the mucous membrane of the nasal cavity, sphenoidal sinus, and frontal sinus; to the skin of the eyebrow, eyelids, forehead, and nose; and to the tentorium cerebelli, dura mater, and the posterior area of the falx cerebri. At first glance, one might not expect one interested in the diagnosis and treatment of orofacial pain and temporomandibular joint disorders to have a need to be concerned with the ophthalmic division. Although much of this division's influence is dedicated to structures within the orbit, nose, and cranium, still, the ophthalmic division may be afflicted with a lesion or structural disorder which can cause all sorts of orofacial pain. Ignorance of this or any portion of the trigeminal nerve will lead to diagnostic and therapeutic failures. In this, the second of four (4) articles concerning the trigeminal nerve, the first division of this vast cranial nerve will be described in detail.