What Is the Lobular Branch of the Great Auricular Nerve? Anatomical Description and Significance in Rhytidectomy

Deep Neck Contouring: Indications and Techniques

A deep comprehension of key anatomical issues, along with the targeted application of suitable therapies, is vital for attaining exceptional neck contours. Traditional surgical approaches often focus solely on modifying subcutaneous fat and, occasionally, the platysma muscle, neglecting subplatysmal structures. This narrow focus may yield less-than-ideal results and potentially exacerbate existing issues, leading to additional contour abnormalities that prove challenging to correct. In fact, in most cases, there are additional factors deep to the platysma-such as subplatysmal fat, the anterior bellies of the digastric muscles, perihyoid fascia, and the submandibular glands-that contribute to obtuse neck contours. For these patients, accessing the neck through a submental incision allows for precise management of these deep neck structures as required. Unfamiliarity with deep anatomical structures can deter surgeons from performing subplatysmal procedures due to unwarranted concerns about increased complication risks. However, both published clinical series and our clinical experience indicate favorable long-term outcomes with natural, refined, harmonious neck contours and a minimal rate of complications. This article serves as a comprehensive guide, describing indications, strategies, and providing a step-by-step description of the senior author's techniques for mastering deep neck contouring.

Microneurography as a minimally invasive method to assess target engagement during neuromodulation

Objective.Peripheral neural signals recorded during neuromodulation therapies provide insights into local neural target engagement and serve as a sensitive biomarker of physiological effect. Although these applications make peripheral recordings important for furthering neuromodulation therapies, the invasive nature of conventional nerve cuffs and longitudinal intrafascicular electrodes (LIFEs) limit their clinical utility. Furthermore, cuff electrodes typically record clear asynchronous neural activity in small animal models but not in large animal models. Microneurography, a minimally invasive technique, is already used routinely in humans to record asynchronous neural activity in the periphery. However, the relative performance of microneurography microelectrodes compared to cuff and LIFE electrodes in measuring neural signals relevant to neuromodulation therapies is not well understood.Approach.To address this gap, we recorded cervical vagus nerve electrically evoked compound action potentials (ECAPs) and spontaneous activity in a human-scaled large animal model-the pig. Additionally, we recorded sensory evoked activity and both invasively and non-invasively evoked CAPs from the great auricular nerve. In aggregate, this study assesses the potential of microneurography electrodes to measure neural activity during neuromodulation therapies with statistically powered and pre-registered outcomes (https://osf.io/y9k6j).Main results.The cuff recorded the largest ECAP signal (p< 0.01) and had the lowest noise floor amongst the evaluated electrodes. Despite the lower signal to noise ratio, microneurography electrodes were able to detect the threshold for neural activation with similar sensitivity to cuff and LIFE electrodes once a dose-response curve was constructed. Furthermore, the microneurography electrodes recorded distinct sensory evoked neural activity.Significance.The results show that microneurography electrodes can measure neural signals relevant to neuromodulation therapies. Microneurography could further neuromodulation therapies by providing a real-time biomarker to guide electrode placement and stimulation parameter selection to optimize local neural fiber engagement and study mechanisms of action.

Essential Surgical Anatomy for Facelift

It is crucial for a facelift surgeon to have a comprehensive understanding of ageing-related changes on the volume, elasticity, and relative position of various facial tissues and layers. These changes lead to an alteration in the surface topography, contour, and ultimately shape of the face. The depressions and sagging of tissues created as a result of ageing then has a bearing on one's perceived age. This article describes the various layers of the face and neck affected by ageing. The fat compartments, superficial musculoaponeurotic system (SMAS), potential facial spaces, facial ligaments, and facial nerve are discussed in detail. Safe and effective execution of facelift requires a thorough understanding of the intricate relationship between the various layers of face and neck, in particular the path of facial nerve, as it negotiates between these layers. The emphasis of this article is on integrating this knowledge to generate practical tips for safe dissection, effective tissue movement, and repositioning during various type of facelift procedures.

Modified Skin Incision and Location of Burr-Hole Surgery via a Retrosigmoid Approach: An Anatomical Study

Objective  This study aims to reduce the tissue damage during craniotomy with retrosigmoid approach. A modified sickle-shaped skin incision was developed, and a new burr-hole positioning method was proposed. Methods  Five adult cadaveric heads (10 sides) were used in this study. The sickle-shaped skin incision was performed during craniotomy. The nerves, blood vessels, and muscles were observed and measured under a microscope. Additionally, 62 dry adult skull specimens (left sided, n  = 35; right sided, n  = 27) were used to measure the distance between the most commonly used locating point (asterion [Ast] point) and the posteroinferior point of the transverse sigmoid sinus junction (PSTS) (Ast-PSTS), as well as the distance between the new locating O point and the PSTS (O-PSTS). Then, the reliability of the new locating O point was validated on the same five adult cadaveric heads (10 sides) used for the sickle-shaped skin incision. Results  The sickle-shaped skin incision reduced the damage to the occipital nerves, blood vessels, and muscles during the surgery via a retrosigmoid approach. The dispersion and variability of O-PSTS were smaller than those of Ast-PSTS. Conclusion  The sickle-shaped skin incision of the retrosigmoid approach can reduce the tissue damage and can completely expose the structures in the cerebellopontine angle. The modified O point is a more reliable locating point for a burr-hole surgery than the Ast point.

Defining a Preauricular Safe Zone: A Cadaveric Study of the Frontotemporal Branch of the Facial Nerve

BACKGROUND

In the preauricular region, the frontotemporal branch of the facial nerve is vulnerable to injury, which can result in facial palsy and poor cosmesis after surgical interventions.

OBJECTIVES

The purpose of this study was to describe variations in the branching patterns of the frontotemporal branch of the facial nerve and the relation between this branch and the surrounding anatomic landmarks. Based on our findings, we propose a Danger Zone and Safe Zones for preauricular interventions to avoid frontal branch injury.

METHODS

Twenty cadaveric half-heads, 10 freshly frozen and 10 embalmed, were dissected. The anatomy of the auriculotemporal nerve, facial nerve, and variations of its branching pattern in the preauricular region were investigated.

RESULTS

The mean [standard deviation] number of frontotemporal branches crossing the zygomatic arch was 2.05 [0.6]. Beginning from the X point at the apex of the intertragal notch, frontal branches ran over the zygomatic arch at a distance extending from 10 to 31 mm anterior to the tragus, which can be defined as the Danger Zone for frontal branches. Safe Zones A and B are triangular regions located behind and in front of the Danger Zone, respectively.

CONCLUSIONS

Mapping of these Safety and Danger Zones is a reliable and simple approach in preauricular interventions to avoid frontal branch injury because the facial nerve typically has multiple frontal branches. This approach provides practical information for surgeons rather than estimating the trajectory of a single frontal branch from Pitanuy's line.

Ten Tips Based on Anatomy and Design to Refine Face and Neck Lift Surgery

Any face/neck lift operation has a natural flow of slower and speedier portions; slower when dissecting under the superficial musculoaponeurotic system and around nerves while faster during opening, undermining, defatting, and closing. Surgeons can maximize efficiency with these simple maneuvers.

A comprehensive review of the great auricular nerve graft

The great auricular nerve (GAN) is a superficial branch of the cervical plexus that innervates parts of the mandible, auricle, and earlobe. Over the past 30 years, the GAN has become the nerve graft donor of choice for many surgeons for reconstructing injured facial nerves. In this review, we discuss the anatomy and function of the GAN, while focusing on surgical landmarks and the characteristics that make it a suitable nerve graft donor. In addition, we present and summarize published case reports on use of the GAN for grafting. We hope that this review will provide surgeons with an up-to-date and concise reference.

A randomized controlled trial evaluating the hemodynamic impact of ultrasound-guided great auricular nerve block in middle ear microsurgery

BACKGROUND

The peri-operative effectiveness of ultrasound-guided great auricular nerve block (GANB) in patients, especially in adult patients undergoing middle ear microsurgery remains unclear. We hypothesized that ultrasound-guided GANB would decrease the hemodynamic responsiveness to incision and opioid consumption in middle ear microsurgery as well as the post-operative analgesia requirement.

METHODS

Sixty patients undergoing middle ear microsurgery were randomized into two equal groups to receive either a GANB with 2 ml of 0.25% ropivacaine under ultrasound guidance (GANB group) or to receive a blank control intervention (without any performed injection) before general anesthesia inductions. The primary outcomes were hemodynamic changes of MAP (mean artery pressure) and HR (heart rate) to skin incision. The secondary endpoints were to determine the consumptions of propofol and remifentanil during the operation and the incidence of remedial analgesia 48 h post-operation to maintain VAS ≤ 3.

RESULTS

The MAP post incision in GANB group was significantly lower than that in control group (GANB group 93.83 ± 11.72 mmHg vs. control group 100.87 ± 12.65 mmHg, P = 0.029). The increases for MAP and HR post incision were also lower in GANB group (∆MAP GANB group 11.90 ± 8.32 mmHg vs. control group 19.83 ± 10.37 mmHg, P = 0.002; ∆HR GANB group 3.67 ± 5.30 beat min^- 1 vs. control group 8.23 ± 8.56 beat min^- 1, P = 0.016). Remifentanil consumption was significantly decreased in GANB group (GANB group 401.55 ± 100.51 μg h^- 1 vs. control group 697.34 ± 215.45 μg h^- 1, P = 0.000). The incidence of remedial analgesia post-operation in GANB group (5/30) was significantly lower than that in control group (20/30, P = 0.000).

CONCLUSION

Ultrasound-guided GANB decreases the hemodynamic responsiveness to incision and remifentanil consumption in middle ear microsurgery as well as the post-operative analgesia requirement.

TRIAL REGISTRATION

This trial was retrospectively registered at http://www.chictr.org.cn with the registration number of ChiCTR1800014333 on 6 January, 2018.

A Simple Clinical Application for Locating the Frontotemporal Branch of the Facial Nerve Using the Zygomatic Arch and the Tragus

BACKGROUND

The seventh cranial nerve (CN VII), also known as the facial nerve, is an anatomically intricate structure the branches of which serve several physiologic functions. CN VII innervates the muscles of facial expression which are crucial for eye protection, oral competence, and social interaction. The temporal branch, clinically referred to as the frontotemporal branch (FTB), is the most superior of the 5 branches and is at risk during cutaneous surgery of the parotid gland and in the temporal region. Several methods for delineating the FTB trajectory exist, the most widely known being Pitanguy's Line, which is defined as running from 0.5 cm below the tragus to 1.5 cm above the lateral eyebrow. However, variations in eyebrow location, often affected by modern-day cosmetic trends, complicate the accuracy of this approach.

OBJECTIVES

The aim of this study was to develop a surgical landmark to identify FTB location without relying on soft tissue structures.

METHODS

To minimize variation, we chose landmarks that were both consistent and easy to locate based on simple surface anatomy. Twenty-one cadaver hemifaces were dissected in order to locate the FTB in relation to the inferior border of the zygomatic arch and the apex of the tragus.

RESULTS

We found that the mean ± SEM distance from the apex of the tragus to the point where the FTB crossed the inferior border of the zygomatic arch was 3.21 ± 0.05 cm.

CONCLUSIONS

Through the use of this measurement, we aim to avoid the pitfalls of previous techniques by providing a widely applicable clinical tool based on landmarks easily found on any patient.

LEVEL OF EVIDENCE: 4

Relationship of the lobular branch of the great auricular nerve to the tympanoparotid fascia: Spatial anatomy for salvage during face and neck lift

To enable selection of a safer suspension site to use in face and neck lifting procedures, the spatial relationship between the tympanoparotid fascia and the great auricular nerve should be clarified. In this study, we aimed to elucidate the position of the tympanoparotid fascia and the pathway of the lobular branch of the great auricular nerve traversing the tympanoparotid fascia. Twenty hemifaces from non-preserved bequeathed Korean cadavers (5 males, 7 females; mean age, 77.0 years) were dissected to determine the great auricular nerve distribution close to the tympanoparotid fascia of clinical significance for face and neck lift procedures. We observed the tympanoparotid fascia in all specimens (20 hemifaces). The tympanoparotid fascia was located anteriorly between the tragus and intertragic notch. Regarding the spatial relationship between the tympanoparotid fascia and the great auricular nerve, we found the sensory nerve entering the tympanoparotid fascia in all specimens (100%), and the depth from the skin was approximately 4.5 mm; in 65% of the specimens, the lobular branch was found to run close to the tympanoparotid fascia before going into the earlobe. Provided with relatively safer surface mapping to access the tympanoparotid fascia free of the lobular branch of the great auricular nerve, surgeons may better protect the lobular branch by anchoring the SMAS-platysma flap and thread to the deeper superior and anterior portions of the expected tympanoparotid fascia.

The Great Auricular Nerve: Anatomical Study with Application to Nerve Grafting Procedures

BACKGROUND

When it comes to autogenous nerve grafting, the sural and great auricular nerve (GAN) are the 2 nerves predominately used for trigeminal and facial nerve repair. Arising from the second and third cervical ventral rami, the GAN emerges from the posterior border of the sternocleidomastoid coursing superiorly and anteriorly toward the ear.

METHODS

Eleven sides from 5 Caucasian and 1 Asian cadaveric heads (all fresh-frozen) were used. One man and 5 women were used with an age at death ranging from 57 to 91 years, with a mean of 80.3 years. Measurements were made from the inferior border of the ear to the GAN, the GAN to the external jugular vein, and the inferior border of the mastoid process to the GAN; the proximal, medial, and distal diameters of the GAN and the length of the GAN that was obtained from this exposure were also measured.

RESULTS

The mean distance from the inferior border of the mastoid process to the GAN, inferior border of the ear to the GAN, and GAN to the external jugular vein was 27.71, 31.03, and 13.28 mm, respectively. The mean length of the GAN was 74.86 mm. The mean diameter of its distal, middle, and proximal portions was 1.51, 1.38, and 1.58 mm, respectively.

CONCLUSIONS

The GAN is an excellent option for use in nerve grafting for repair of, for example, facial dysfunction. In this study, we review our measurements, techniques for identification, and dissecting techniques for the GAN. The proximity to the operative area and minimal complications associated with GAN grafting might contribute to improved patient satisfaction and better outcomes regarding functional restoration.

Partial Ear Defects

Reconstruction of partial ear defects represents one of the most challenging areas within reconstructive surgery of the head and neck. Each case of auricular reconstruction is unique and warrants a systematic approach that accounts for defect size and location, the quality of the surrounding skin, patient preference, and operator experience. In this article, the authors outline different reconstructive approaches for defects of the upper-, middle-, and lower-third of the auricle. The relevant anatomy is discussed in detail. Successful outcomes in auricular reconstruction rely on the surgeon's careful analysis of the defect as well as knowledge of the different reconstructive options available.

Temple and Postauricular Dissection in Face and Neck Lift Surgery

Periauricular paresthesia may afflict patients for a significant amount of time after facelift surgery. When performing face and neck lift surgery, temple and posterior auricular flap dissection is undertaken directly over the auriculotemporal, great auricular, and lesser occipital nerve territory, leading to potential damage to the nerve. The auriculotemporal nerve remains under the thin outer superficial fascia just below the subfollicular level in the prehelical area. To prevent damage to the auriculotemporal nerve and to protect the temporal hair follicle, the dissection plane should be kept just above the thin fascia covering the auriculotemporal nerve. Around the McKinney point, the adipose tissue covering the deep fascia is apt to be elevated from the deep fascia due to its denser fascial relationship with the skin, which leaves the great auricular nerve open to exposure. In order to prevent damage to the posterior branches of the great auricular nerve, the skin flap at the posterior auricular sulcus should be elevated above the auricularis posterior muscle. Fixating the superficial muscular aponeurotic system flap deeper and higher to the tympano-parotid fascia is recommended in order to avoid compromising the lobular branch of the great auricular nerve. The lesser occipital nerve (C2, C3) travels superficially at a proximal and variable level that makes it vulnerable to compromise in the mastoid dissection. Leaving the adipose tissue at the level of the deep fascia puts the branches of the great auricular nerve and lesser occipital nerve at less risk, and has been confirmed not to compromise either tissue perfusion or hair follicles.