Subfascial dissection and extended temporal muscle detachment for middle fossa approach

BACKGROUND

The soft tissue dissection for the middle fossa approach requires adequate management of the neuro, vascular, and muscular structures in order to maximize exposure and diminish morbidities.

METHODS

An incision anterior to the tragus is performed, extending from the zygomatic process to the superior temporal line. The superior temporal artery is exposed, followed by a subfascial dissection of the frontalis nerve. The temporal muscle is dissected and released from the zygoma. All cranial landmarks are exposed for the 5 × 5 cm temporal fossa craniotomy.

CONCLUSION

This novel approach provides a safe and adequate access to perform an extended middle fossa craniotomy.

The surgical anatomy of the deep temporal nerve: A cadaveric study

BACKGROUND

The aims of this study were to investigate the surgical anatomy of the deep temporal nerve (DTN) and find (fixed/static) anatomical landmarks that could be used during surgery to localise the DTN branches.

METHODS

Ten hemifaces of Dutch cadavers were dissected at the Department of Anatomy of the Radboudumc. Landmarks and measurements of interest were number of branches of the DTN, distance from the tragus to the DTN, and distance from the cranial and caudal parts of the posterior root of the zygomatic bone until the DTN.

RESULTS

In this cadaveric study, 10 hemifaces were dissected (male, n = 6 [60%]; female, n = 4 [40%]) with an equal left/right side division. The number of deep temporal branches varied from 2 (30%) to 3 (70%) per side. The mean distance to the tragus varied from 40 to 53 mm, with a mean distance of 44.3 ± 4.4 mm. The mean distance from the cranial part of the posterior root of the zygomatic bone to the DTN varied from 29 to 35 mm, with a mean distance of 31.3 ± 2.1 mm. The distance from the caudal part of the posterior root of the zygomatic bone to the DTN varied from 8 to 17 mm, with a mean distance of 13.4 ± 3.4 mm.

CONCLUSION

This study investigated the surgical anatomy and landmarks used for identification of the DTN and its branches. It suggested using firm landmarks for nerve identification, such as the posterior root of the cranial and/or the caudal zygomatic bone.

Anatomic landmarks for masseteric nerve identification: Anatomic study for a new reference point

The masseteric nerve is often used as a donor nerve in the treatment of facial paralysis. Even if several anatomical studies described landmarks for its identification, their main disadvantages are the anatomical variability and the changes due to surgery. Sixteen dissections were performed on cadaveric specimens. The masseteric muscle (MM), the zygomatic arch (ZA), the masseteric nerve (MN) and the zygomatic branch of the facial nerve (ZB) were identified and their relationships were measured. The relationships between MN and ZB resulted to be constant, with MN intersecting ZB at a depth of 0,78 cm in the muscle, 1,6 cm below ZA and 0,8 cm from the posterior border of MM. The measures obtained demonstrated as the main zygomatic branch of the facial nerve can be a suitable landmark for the identification of the masseteric nerve, with no variations due to the surgical procedure or patient characteristics.

[DIAGNOSTICS OF POSITION OF THE MOTOR AND TRIGGER POINTS: OF THE CHEWING MUSCLES FOR ZYGOMATIC COMPLEX FRACTURES]

Existing treatment methods of zygomatic complex fractures, which are complicated by contrac- ture of the masseter as a result of displaced bone fragments, have to be improved. Lack of muscle relaxation leads to the formation of local hypertonicity. In spasmodic muscle fibers varies perfusion and hypoxia occurs, which is accompanied by the release of inflammatory mediators and activation of pain receptors. Over time, areas formed local hypertonicity specific trigger points that contain multiple sensory loci and include one or more sensitive nerve endings. A device for the effective electromyographic study of masseters as a source of their condition and the dynamics of changes in masticatory muscles during patient treatment by improving the fixation system on the face of the patient and the introduction of more perfect spatial coordinate system for mathematical calculations masseter motor position (or triggered) point. Patients were examined before and in the dynamics of treatment according to our methodology, which included proper masseter relaxation, reposition and fixation of bone fragments and further medical therapy.

Branching of the foramen rotundum. A rare variation of the sphenoid

The human orbit communicates with the middle cranial fossa through several canals and openings. Some of them (optic canal, superior orbital fissure) are constant, others (meningo-orbital foramen, Warwick's foramen, metoptic canal) are less frequent. Here we report a rare variation of the foramen rotundum which, opening into the orbit with a branching canal, represented a further connecting pathway between the orbit and the middle cranial fossa. Such variation was detected in about 1.06% of individuals and it was almost always located on the right side. Only in one cases it could be found left-sided and in another skull it was spotted bilaterally. The vari- ation consisted of the branching of a 5 mm long canal from the lateral wall of the foramen rotun- dum that opened into the orbit. In general the diameter of the canal was comprised between 0.5 and 0.6 mm but it could be as large as 1 mm or as thin as 0.2 mm. The canal, straight and directed slightly superolaterally, likely transmitted the zygomatic nerve and/or part of the infraorbital nerve. To our knowledge, an independent entrance through a dedicated canal of such nerves has never been reported. The surgeons operating in this region, either neurosurgeons or ophthalmologists, should be aware of the possible variation in the course of these nerves.

Cutaneous Distribution of Zygomaticofacial Nerve

The aim of this study is to elucidate the cutaneous distribution of the zygomaticofacial nerve (ZFN). Twenty hemifaces of 10 adult Korean cadavers were dissected. ZFN-innervated limits were rectangular and each side was 18.8 +/- 4 mm and 15.8 +/- 3.4 mm. The center of the rectangle was located laterally at 17.3 +/- 5.5 mm from the lateral canthus and then inferiorly at 18.1 +/- 3.1 mm. The cutaneous area innervated by the ZFN was rectangular shaped having a horizontal side that was 9.3 +/- 4% to 27.3 +/- 7.5%of the line from the lateral canthus to the root of helix and a vertical side that was 13.9 +/- 5.8% to 35.7 +/- 5.4% of the line from the lateral canthus to the oral commissure level. Knowledge of ZFN innervation is available with an intraoral approach in maloplasty or midface lift.

Evaluation of cutaneous sensibility on infraorbital nerve area

Normal facial sensibility on the area of the infraorbital nerve was determined in 24 healthy subjects. The measurement of two points discrimination distance and the evaluation of cutaneous pressure threshold were assessed on both sides on the zygomatic, paranasal, and superior labial skin. Cutaneous sensibility varied from region to region but was consistent from one normal individual to another. Cutaneous sensibility of the superior labial skin was more accurate than zygomatic and paranasal skin in all tests. Sex and dominant sides did not have significant influence on the results. The measurement of two point discrimination distance and the evaluation of cutaneous pressure threshold provided reliable and reproducible data that can be used as a standard to determine facial cutaneous sensibility.

The Frontal-Temporal Nerve Triangle: A New Concept of Locating the Motor and Sensory Nerves in Upper Third of the Face Rhytidectomy

BACKGROUND

How to avoid damage to the temporal branch of the facial nerve has long been a central topic of discussion. Recently, damage to the supraorbital nerve, the auriculotemporal nerve, and other branches of the trigeminal nerve divisions has attracted much attention. Focusing on frontal and temporal rhytidectomy, the authors have investigated the course and distribution of the facial nerve branches, the supraorbital nerve, the auriculotemporal nerve, and other branches of trigeminal division. In this article, they present the concept of the frontal-temporal nerve triangle; its contents, vicinity, and clinical significances are discussed.

METHODS

An anatomical study was performed using 30 temporal-parietal regions of 10 fixed adult cadavers and five fresh cadavers. A step-by-step dissection from the superficial layer to the deep layer was involved; all the measurement data were analyzed, and the mean and standard deviation were calculated and expressed in centimeters.

RESULTS

The frontal-temporal nerve triangle is an approximately triangular area formed by the temporal branch of the facial nerve, the supraorbital nerve, and the auriculotemporal nerve. Together with its contents and vicinal structures, it forms a complicated three-dimensional rather than two-dimensional structure. Anatomical structures closely associated with rhytidectomy are located in or near this area.

CONCLUSIONS

Acting as the anatomical body surface landmark for preoperatively locating the temporal branch, the supraorbital nerve, the auriculotemporal nerve, and its related structures, the concept of the frontal-temporal nerve triangle has practical significance in designing incisions and selecting planes of dissection in upper third of the face rhytidectomy.

Anatomic Guides to Precisely Localize the Zygomatic Branches of the Facial Nerve

Descriptions of superficial anatomic landmarks for the identification of the zygomatic branches of the facial nerve, and their relevance for plastic surgery, are lacking in the literature. This paper provides such a description and discusses its relevance to facial surgery.

MATERIALS AND METHODS

Sixty-six specimens, including the parotid region, from 33 adult cadavers were dissected and studied. All specimens were fixed in formaldehyde, and the superficial tissues were removed and the zygomatic branches of the facial nerve, the parotid gland, the tragus and the lateral palpebral commissure were identified. The vertical and horizontal relationships were recorded and analyzed.

RESULTS AND CONCLUSIONS

A total of 69.7% of the cadavers had two branches, 25.8% had three branches, and 4.5% had a single zygomatic branch. The mean horizontal distance of the zygomatic branch (the most upper one) as it emerged from the anterior border of the parotid gland and the tragus was 30.71 mm, whereas the mean vertical distance of the zygomatic branch from the midpoint between the tragus and the lateral palpebral commissure was 19.29 mm. The branching patterns with the buccal branches were reported. There were no statistical differences between the left and right sides or between the sexes. The zygomatic branches of the facial nerve were always under the oblique line between the tragus and the lateral palpebral commissure and have a close relationship with the buccal branches of the facial nerve under this anatomic landmark. Application of the results in facial surgery is discussed.

The Anatomy of Temporal Hollowing: The Superficial Temporal Fat Pad

A coronal incision provides exposure to the lateral craniofacial skeleton for plastic surgeons, oral-maxillofacial surgeons, head and neck surgeons, neurosurgeons, and cosmetic surgeons. A common complication of this approach is hollowing of the temporal fossa. This hollowing results in a significant cosmetic deformity that affects the patient physically and psychologically. Current theories suggest that hollowing may result from atrophy of the superficial temporal fat pad resulting from ischemia, displacement, or denervation of the fat pad. The purpose of this study is to identify the neurovascular supply and the supporting structures of the superficial temporal fat pad. Eight fresh-frozen cadaver heads were injected with latex to facilitate identification of vessels. Through coronal incisions, the anatomy of the vessels, nerves, and fascial network within the superficial temporal fat pads were recorded. The vascular supply of the superficial temporal fat pad includes branching perforators from the deep and middle temporal arteries that traverse through the substance of the fat pad. The branches of the zygomaticotemporal nerve travel through the superficial temporal fat pad. There is a network of septations that suspends the superficial temporal fat pad to the anterior fascia. This is the first step to understanding the etiology of postoperative temporal hollowing. This study provides the basis for a prospective, randomized clinical trial investigating temporal hollowing after different surgical exposures of the area.

The Anatomy of Temporal Hollowing: The Superficial Temporal Fat Pad

A coronal incision provides exposure to the lateral craniofacial skeleton for plastic surgeons, oral-maxillofacial surgeons, head and neck surgeons, neurosurgeons, and cosmetic surgeons. A common complication of this approach is hollowing of the temporal fossa. This hollowing results in a significant cosmetic deformity that affects the patient physically and psychologically. Current theories suggest that hollowing may result from atrophy of the superficial temporal fat pad caused by ischemia, displacement, or denervation of the fat pad. The purpose of this study is to identify the neurovascular supply and the supporting structures of the superficial temporal fat pad. Eight fresh-frozen cadaver heads were injected with latex to facilitate identification of vessels. Through coronal incisions, the anatomy of the vessels, nerves, and fascial network within the superficial temporal fat pads were recorded. The vascular supply of the superficial temporal fat pad includes branching perforators from the deep and middle temporal arteries that traverse through the substance of the fat pad. The branches of the zygomaticotemporal nerve travel through the superficial temporal fat pad. There is a network of septations that suspends the superficial temporal fat pad to the anterior fascia. This is the first step to understanding the etiology of postoperative temporal hollowing. This study provides the basis for a prospective randomized clinical trial investigating temporal hollowing after different surgical exposures of the area.

Pattern of the Temporal Branch of the Facial Nerve in the Upper Orbicularis Oculi Muscle

The purpose of this study is to clarify a pattern of the temporal branch of the facial nerve in the upper orbicularis oculi muscle (OOM) and an impact in exploiting the frontalis myofascial advancement flap. The authors investigated the pattern of the temporal branch of the facial nerve in the upper OOM in 20 cadavers. The highest and lowest level of the nerve coursing into the OOM were measured at three different sagittal/vertical planes through the lateral canthus, midpalpebral fissure, and medial canthus, respectively. The authors designate a hazard zone that delineates a circle with 1.0-cm diameter and its center located inferiorly and laterally in the direction of -15 degrees 7.5 cm from the lateral canthus. The highest level of the those twigs that entered OOM on the X-axis and Y-axis with the origin of lateral canthus is +2.51 +/- 0.23 cm, +2.70 +/- 0.35 cm, and the lowest is 0 cm, +2.68 +/- 0.32 cm, respectively. The highest level of the those twigs on the Y-axis with the origin of lateral canthus, mid-palpebral fissure, and medial canthus is +3.47 +/- 0.27 cm, +3.49 +/- 0.45 cm, and +2.97 +/- 0.35 cm, and the lowest is +1.62 +/- 0.12 cm, +1.82 +/- 0.17 cm, and +1.63 +/- 0.22 cm, respectively. Those twigs of the temporal branch of the facial nerve coursed horizontally along the fibers of OOM with interconnections but did not cross over the superior orbital rim. The authors describe details of the temporal branch of the facial nerve in the OOM and designate a hazard zone, wherein the temporal branch should be spared. They also assure that injury of the temporal branch of the facial nerve is inevitable in the procedure of the frontalis myofascial advancement flap.

Successful treatment of hemifacial spasm with selective facial nerve block using doxorubicin (adriamycin) under local anesthesia

OBJECTIVE

To describe our experience with selective chemical rhizotomy of facial nerves using adriamycin (ADM) in a patient with hemifacial spasm (HFS). This unique technique is less invasive than intracranial neurosurgery and enables one to perform a permanent nerve block under local anesthesia.

PATIENT

The patient, a 73-year-old female, had difficulty opening her left eye. Following unsuccessful treatment with anti-epileptic medicine, she received selective intraneural injections of ADM under local anesthesia. One week after the surgery the spasms had disappeared completely. No major complications were caused by this procedure and there had been no recurrence of spasms 3 years after the surgery.

RESULTS

It is thought that recurrence of HFS should be observed after simple neurotomy due to regrowth of nerve fibers. However, this did not occur after chemical rhizotomy with ADM. This method clearly differs from previously used varieties of simple neurotomy because the latter technique does not cause severe destructive changes in the facial motor nucleus.

CONCLUSION

Selective facial nerve chemical rhizotomy with ADM under local anesthesia may be effective in treating a subgroup of patients with HFS, especially elderly patients and those in the high-risk group for general anesthesia and intracranial neurosurgery.

Zygomaticotemporal Nerve Passage in the Orbit and Temporal Area

Injury of the zygomaticotemporal nerve causes paresthesia in its distributed area, and its entrapment induces protractive pain in case of manipulation of the orbital lateral wall, a Gillies or Dingman reduction procedure for a zygomatic fracture, or an endoscopic subperiosteal facelift. The aim of this study was to elucidate the surgical anatomy of the zygomaticotemporal nerve in the orbit and temporal area. Twenty hemifaces from 10 adult Korean cadavers (10 male and 10 female) were used in the study. The zygomaticotemporal nerve ran along the lateral wall of the orbit, passed through the zygomaticotemporal foramen, and reached to the temporal fossa. The point where the zygomaticotemporal nerve appears at the margin of zygomatic bone is defined as the vulnerable point (Vp); hence, the nerve might be injured during surgical procedures. The Vp was 11.29 +/- 2.65 mm below the zygomaticofrontal suture and 21.76 +/- 2.76 mm from the superior border of zygomatic arch. The most vulnerable points were within a 10-mm diameter circle (vulnerable zone). Its center was 11 mm from the zygomaticofrontal suture at an angle of 45 degrees inferolaterally. The zygomaticotemporal nerve ran between the deep layer and the superficial layer of the deep temporal fascia. It ran just superficial to the deep layer of the deep temporal fascia toward the temporal area and innervated the temporal skin. The area innervated by terminal branches of the zygomaticotemporal nerve included a circle with 30-mm diameter, with the center located 10 mm superior to the top of the auriculocephalic sulcus and 30 mm lateral to the lateral canthus. Precautions should be taken when working in the area of the vulnerable zone during the Dingman procedure involving periorbital incision in case of zygomatic fracture.

[Prevention of the zygomatic branch of the facial nerve in rhytidectomy: an anatomical study]

OBJECTIVE

To investigate the anatomical distribution of the zygomatic branch of the facial nerve and discuss its clinical significance in the rhytidectomy.

METHODS

The distribution of the zygomatic branch of the facial nerve was observed on 30 halves of the fifteen candaveric specimens (10 antiseptic cadaveric specimens and 5 fresh cadavers).

RESULTS

The zygomatic branch made its way through the upper or the anterior border of the parotid gland, giving rise to 2 or 3 rami, which could be divided into the superior and the inferior rami. The superior rami, which were thin and superficial, crossed the zygomatic arch at its inner one-third or ran along the inferior margin of the zygomatic arch, and then entered beneath the zygomatic ligaments. The inferior rami were comparatively thick and deep, lying 1.0+/-0.3 cm inferior to the superior rami. The inferior and superior rami joined each other on the surface and deep side of the zygomatic major muscle.

CONCLUSION

In the prevention of the zygomatic branch damage in rhytidectomy, the areas where caution should taken were the anterior border of the zygomatic major muscle in sub-SMAS dissection and the zygomatic arch in the subperiosteal dissection. The sharp dissection and excess tension should be avoided to reduce the nerve injury.

Nervous branch passing through an accessory canal in the sphenozygomatic suture: the temporal branch of the zygomatic nerve

A nervous branch which passes through a small canal in the sphenozygomatic suture is sometimes observed during dissection. To examine the origin, course and distribution of this nervous branch, 42 head halves of 21 Japanese cadavers (11 males, 10 females) and 142 head halves of 71 human dry skulls were used. The branch was observed in seven sides (16.7%); it originated from the communication between the lacrimal nerve and the zygomaticotemporal branch of the zygomatic nerve or from the trunk of the zygomatic nerve. In two head halves (4.8%), the branch pierced the anterior part of the temporalis muscle during its course to the skin of the anterior part of the temple. The small canal in the suture was observed in 31 head halves (21.8%) of the dry skulls. Although this nervous branch is inconstantly observed, it should be called the temporal branch of the zygomatic nerve according to the constant positional relationship to the sphenoid and zygomatic bones. According to its origin, course and distribution, this nervous branch may be considered to be influential in zygomatic and retro-orbital pain due to entrapment and tension from the temporalis muscle and/or the narrow bony canal. The French version of this article is available in the form of electronic supplementary material and can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00276-002-0027-4.

The course of the temporal branch of the facial nerve in the periorbital region

PURPOSE

This study identified the terminal temporal and zygomatic branches of the facial nerve as they enter the orbicularis oculi muscle and related these branches to identifiable surface markings.

MATERIALS AND METHODS

The temporal and zygomatic branches of the facial nerve were dissected from 5 preserved cadavers (10 sides). The most superior temporal branch entering the orbicularis oculi muscle was identified and related to the lateral canthus of the eye. A vertical line was passed through this point so that the line was equidistant from the nasal tip and chin point. A line perpendicular to the vertical line through the lateral canthus served as the horizontal scale. Vertical and horizontal lines through the lateral canthus were used to establish the anatomic relationship between the lateral canthus and the branch of the temporal nerve entering the orbicularis oculi muscle.

RESULTS

The temporal branch was an average of 2.85 +/- 0.69 cm superior to the lateral canthus and an average of 2.54 +/- 0.43 cm lateral to the lateral canthus as it courses into the orbicularis oculi muscle. At the lateral border of the orbicularis oculi muscle, where the temporal and zygomatic nerves insert into the muscle, the mean vertical distance between the temporal and zygomatic nerves was 1.72 +/- 0.62 cm.

CONCLUSION

Incisions superior or inferior and parallel to the course of the facial nerve, can provide access to the fronto zygomatic suture and the superior and lateral orbit without damaging its branches.

Subfascial and submuscular methods of temporal muscle dissection and their relationship to the frontal branch of the facial nerve. Technical note

The microsurgical anatomy of the temporal and zygomatic branches of the facial nerve are presented along with related local vasculature (frontal and parietal branches of the superficial temporal artery [STA]) as encountered when using subfascial and submuscular temporal muscle dissection techniques for anterolateral craniotomies. Twenty sides were studied in 10 cadaveric specimens that had been previously injected with latex. The rami of the temporal and zygomatic branches of the facial nerve and branches of the STA were dissected out through pterional and orbitozygomatic approaches by using a submuscular or subfascial temporal muscle dissection technique. The three rami of the temporal branch of the facial nerve (the auricularis, frontalis, and orbicularis) were found to run within the galeal plane of the scalp. The zygomatic branch of the facial nerve was found to course deeper than the most caudal extension of the galea, known as the superficial musculoaponeurotic layer. The frontal branch of the STA served as an important landmark for the subfascial or submuscular dissections because excessive reflection of the scalp flap inferior to the level of this vessel would inadvertently injure the frontalis branch of the facial nerve. Subfascial and submuscular dissections of the temporal muscle offer an alternative to the interfascial technique during anterolateral craniotomies. Scalp and temporal dissection performed with careful attention to anatomical landmarks (frontal branch of the STA and the suprafascial fat pad) provides a safe and expeditious alternative to the traditional interfascial technique.

Surgical management of the facial nerve in craniofacial trauma and long-standing facial paralysis: cadaver study and clinical presentations

BACKGROUND AND OBJECTIVES

Examination of the extratemporal branches of the facial nerve reveals several branching patterns of the facial nerve, indicating the variability in the course of the nerve. Due to such variance, injury to this nerve often accompanies facial trauma and surgical dissection for the repair of facial bone injuries, and it may result in high morbidity.

METHODS AND MATERIALS

A study of 12 fresh cadavers was performed to 1) review the variability in location of the extratemporal branches of the facial nerve, 2) identify the soft tissue injuries in which the facial nerve is at risk, and 3) discuss surgical options for repair. The authors identified the zygomatic and buccal and the extratemporal branches of the facial nerve. Among the five extratemporal branches, there is a significant crossover between all, except the temporal and the mandibular branches. This indicates that dissection should proceed with great caution, since injury to the temporal and marginal mandibular branches is unlikely to resolve spontaneously. The management of injuries within one year and those of longer duration is discussed.

RESULTS AND/OR CONCLUSIONS

Two of the 5 major branches of the extratemporal facial nerve have a high morbidity following injury. Repair should be performed within the first 72 hours. Graft, if required, should be placed in 9 to 12 months.

How to block and tackle the face

Regional blocking techniques as noted in dentistry, anesthesia, and anatomy texts may result in inconsistent and imperfect analgesia when needed for facial aesthetic surgery. The advent of laser facial surgery and more complicated aesthetic facial procedures has thus increased the demand for anesthesia support. Surgeons should know a fail-safe method of nerve blocks. Fresh cadaver dissections are used to demonstrate a series of eight regional nerve-blocking routes. This sequence of bilateral blocks will routinely provide profound full facial anesthesia. Certain groupings of blocks are effective for perioral or periorbital laser surgery.

The temporal branch of the facial nerve: how reliably can we predict its path?

A thorough examination of the temporal branch of the facial nerve was performed to characterize precisely the number of rami crossing the zygomatic arch and their location with respect to bone and soft-tissue landmarks. Fresh cadaver dissection was performed in 12 facial halves, dissecting the facial nerve superiorly from the stylomastoid foramen to identify all branches crossing the zygomatic arch. There were a median of three (range two to four) rami of the temporal branch crossing the lower aspect of the zygomatic arch, with distinct anterior and posterior divisions identified in each dissection. In 8 of the 12 dissections, one or more separate middle divisions of the nerve also were seen at the inferior aspect of the zygomatic arch. Superior to the zygomatic arch, frequent interconnections were noted between all divisions of the temporal branch, but no connections were noted to other branches of the facial nerve. Previous descriptions of the course of the temporal branch based on soft-tissue landmarks most closely correlated with nerve rami that were found in the present study to be located within the anterior division of the nerve. On crossing the inferior aspect of the zygomatic arch, the anterior and middle divisions of the temporal branch were located a median of 12 and 4 mm anterior to the articular eminence, respectively; the posterior division ranged in location from 10 mm posterior to 7 mm anterior to the articular eminence. The range over which rami of the temporal branch crossed the inferior aspect of the zygomatic arch was equally divided anterior and posterior to the articular eminence and covered up to 50 percent of the total length of the zygomatic arch. The present study confirms that the temporal branch is not a single nerve branch but consists of multiple rami that cross the zygomatic arch anywhere for over half the length of its inferior border. Techniques for localizing the nerve based on reference points from two soft-tissue landmarks are therefore unreliable.

Endoscopic-assisted wire removal and neurolysis

Endoscopic-assisted surgery allows remote incision placement and provides an illuminated, magnified operative field. We have applied these principles to perform neurolysis of the zygomaticotemporal nerve and removal of a fixation wire under endoscopic control in a patient with pain and tenderness at the site of a previous zygomatic arch fracture. Endoscopic assistance aided dissection by placing the incision in a hidden, unscarred area.

The zygomatic branch of the auriculopalpebral nerve: can it be normally palpated in the live horse?

A detailed description is given of the methods to locate and palpate a subcutaneous part of the zygomatic branch of the auriculopalpebral nerve in 9 out of 10 adult horses examined. This permits the exact placing of local anaesthetic along the nerve branch at the described site, resulting in the akinesis of the m orbicularis oculi and the elimination of the blink reflex. This facilitates ophthalmologic examination and possible treatment of some eye conditions.

Precise repair of orbital maxillary zygomatic fractures

OBJECTIVE

To demonstrate the techniques, advantages, indications, and potential pitfalls of the transconjunctival approach with lateral canthotomy, sublabial approach, and coronal approach in the treatment of complex trimalar fracture with associated blow-out fractures.

DESIGN

All patients diagnosed as having complex trimalar fractures with or without blow-out treated by either of us over a 2-year period were included. Follow-up ranged from a minimum of 6 months to 2 years.

SETTING

All patients were treated with December 1989 to December 1991 at either Louisiana State University Medical Center, Shreveport, or University of Kansas Medical Center, Kansas City.

PATIENTS

Eighteen patients with complex trimalar fractures were included in this study. Eight patients had associated orbital blow-out fractures. Simple isolated arch fractures were excluded.

INTERVENTION

All subjects underwent a transconjunctival approach with lateral canthotomy. Seven subjects also had associated sublabial flaps. Five patients required hemicoronal or coronal approaches.

RESULTS

There were seven minor complications. Ninety-three percent (14/15 [three didn't respond to the survey]) of patients surveyed were either very satisfied or satisfied with their functional and cosmetic results.

CONCLUSION

The management of complex trimalar fracture with blow-outs is greatly facilitated by the rational application of the described techniques.

[Facial nerve preservation in the region of the zygomatic arch]

In order to preserve the frontotemporal branch of the facial nerve in frontotemporal and trans-zygomatic craniotomies, electromyographic responses from the facial muscles were recorded preoperatively. Incising the frontotemporal branch of the facial nerve could be avoided by identifying the crossing point of the frontotemporal branch of the facial nerve on the superior border of the zygomatic arch. The crossing points were investigated in 20 patients and in most cases they existed between 2 cm and 6 cm from the anterior border of the external auditory canal. Another important point to preserve the facial nerve is to conserve the layer in which the facial nerve is included. Therefore, the surgical anatomy in the region of the zygomatic arch and temporal area was reviewed in detail. This knowledge is crucial for neurosurgeons to dissect precisely in this region without causing postoperative facial palsy.

A technique for reducing fractures of the zygomatic complex under local anaesthesia

Fractures of the zygomatic complex are common. A technique is described which enables the majority of these fractures to be reduced under local anaesthetic, intravenous sedation and analgesia on an out-patient basis. The benefits to the patient and to the hospital are highlighted.

Bradycardia during elevation of a zygomatic arch fracture

A case of bradycardia occurring during elevation of a zygomatic arch fracture is reported and possible mechanisms for the phenomenon are discussed. This case report serves to alert oral and maxillofacial surgeons and anesthesiologists to a possible hazard during surgical elevation of a fractured zygomatic arch.

Experiments on antidromic evoked potentials of the facial nerve. A possible electroneurodiagnostic examination of intratemporal facial nerve paralysis

Registering of AEPs of the facial nerve was attempted both in animals and in human subjects. In animal experiments using cats and guinea pigs, electrical stimulus was given to the zygomatic branch. The neural responses registered from the electrode placed on the fallopian canal or on the posterior wall of the external auditory canal were verified to be the AEP. The AEP appeared to be a sensitive and simultaneous indicator of the neural compression damage. In the human experiments, the three major peripheral branches were transcutaneously stimulated, and the AEPs were registered in the depth of the external auditory canal. The marginal mandibular branch was thought to be the most suitable branch of the transcutaneous stimulation for human application. The AEPs registered from a patient with Bell's palsy was demonstrated.

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.

Surgical anatomy of the extraparotid distribution of the facial nerve

The peripheral, extraparotid distribution of the clinically important branches of the facial nerve is described, with common variations, based on the anatomical dissection of 35 cadaver half heads. Methods are suggested for avoiding, isolating, and protecting the facial nerve branches during surgical procedures.

Surgical anatomy of the pterygopalatine fossa

The pterygopalatine fossa is the distribution centre for the main vessels and nerves of the middle third of the face. Its surgical anatomy is discussed, with particular emphasis on the relationship between the medical plate of the pterygoid process of the sphenoid bone and the vertical plate of the palatine bone; the position of the several foramina is reviewed also. It is stressed that the vascular contents of the pterygopalatine fossa lie in a coronal plane, anterior to the neural contents. Finally, a short review is given of the different surgical approaches to the pterygopalatine fossa. It is concluded that the transantral approach to the fossa, as originally described by Carnochan (1858), still seems to be the best way to gain access to this space.