Head and neck fascia and compartments: no space for spaces

Facial nerve dissection in parotid surgery: a microscopic investigation study

In parotid surgery, it is crucial to identify and preserve the facial nerve, which runs through the parotid gland. The purpose of this study was to histologically clarify two clinical questions: whether "superficial" and "deep" lobes exist anatomically and what are the structures surrounding facial nerve. Parotid gland tissues were obtained from dissection of donated cadavers. The gland was cut perpendicular to the facial nerve plane at 5 mm intervals, and the pieces were embedded in paraffin, thinly sliced, and stained. The morphology of the nerve was observed at each site, and the relationships between the thickness of the perineural tissue (defined as the tissue between the groups of nerve fasciculi and the glandular parenchyma), nerve diameter, and distance from the proximal end of the nerve were examined. In addition, the dissection layer was examined histologically in isolated parotid tissues. The interlobular connective tissue was spread like a mesh within the parotid gland and subdivided the glandular parenchyma. The facial nerve was located in the interlobular connective tissue, and its course was not restricted to the boundary plane between the superficial and deep lobes. The thickness of the perineural tissue decreased with increasing distance from the proximal end of the nerve. The dissection layer was clarified that located in the perineural tissue. The perineural tissue is thinner in more distal regions, which may make dissection more difficult there. No particular anatomical structure appears to separate the superficial and deep lobes.

Mylohyoid Muscle: Current Understanding for Clinical Management Part II: Clinical Anatomy, Radiology, and Surgical/Clinical Relevance

The mylohyoid is one of the suprahyoid muscles along with the geniohyoid, digastric, and stylohyoid muscles that lies between the anterior belly of the digastric muscle inferiorly and the geniohyoid superiorly. In Part II, the radiology and clinical/surgical importance of the mylohyoid muscle will be discussed.

The assessment and management of deep neck space infections in adults: A systematic review and qualitative evidence synthesis

OBJECTIVES

To summarise current practices in the diagnosis and management of deep neck space infections (DNSIs). To inform future studies in developing a framework in the management of DNSIs.

DESIGN

This review was registered on PROSPERO (CRD42021226449) and reported in line with PRISMA guidelines. All studies from 2000 that reported the investigation or management of DNSI were included. The search was limited to English language only. Databases searched included AMED, Embase, Medline and HMIC. Quantitative analysis was undertaken with descriptive statistics and frequency synthesis with two independent reviewers. A qualitative narrative synthesis was conducted using a thematic analysis approach.

SETTING

Secondary or tertiary care centres that undertook management of DNSIs.

PARTICIPANTS

All adult patients with a DNSI.

MAIN OUTCOME MEASURES

The role of imaging, radiologically guided aspiration and surgical drainage in DNSIs.

RESULTS

Sixty studies were reviewed. Thirty-one studies reported on imaging modality, 51 studies reported treatment modality. Aside from a single randomised controlled trial, all other studies were observational (n = 25) or case series (n = 36). Computer tomography (CT) was used to diagnose DNSI in 78% of patients. The mean percentage of management with open surgical drainage was 81% and 29.4% for radiologically guided aspiration, respectively. Qualitative analysis identified seven major themes on DNSI.

CONCLUSIONS

There are limited methodologically rigorous studies investigating DNSIs. CT imaging was the most used imaging modality. Surgical drainage was commonest treatment choice. Areas of further research on epidemiology, reporting guidelines and management are required.

Fascial layers encountered in the lateral skull base region: A cadaveric and radiological analysis

BACKGROUND

In our experience, the anterior carotid sheath forms an important plane of dissection when excising temporal bone region cancers. However, its anatomical composition, relationships, and radiological appearance remains unclear.

METHODS

Eight sides of cadaveric heads were dissected. Anatomical findings were correlated with a high-resolution baseline T1 MRI.

RESULTS

The anterior carotid sheath was formed by the tensor-vascular-styloid fascia, stylopharyngeal fascia, buccopharyngeal fascia (BPF), and longus capitis fascia (LCF), and appeared as a hypointense line on MRI. Not previously described, the glossopharyngeal nerve pierced the sheath 9.0 mm (SD 2.1 mm) below the skull base and traveled through its LCF and BPF layers to exit near the pharynx.

CONCLUSION

Multiple fascial layers formed the anterior carotid sheath at the skull base, and this was radiologically identifiable. Further studies are required to validate findings and investigate the role this fascial plane has in forming an effective barrier to spread of malignancy.

A three-component model of the spinal nerve ramification: Bringing together the human gross anatomy and modern Embryology

Due to its long history, the study of human gross anatomy has not adequately incorporated modern embryological findings; consequently, the current understanding has often been incompatible with recent discoveries from molecular studies. Notably, the traditional epaxial and hypaxial muscle distinction, and their corresponding innervation by the dorsal and ventral rami of the spinal nerve, do not correspond to the primaxial and abaxial muscle distinction, defined by the mesodermal lineages of target tissues. To resolve the disagreement between adult anatomy and embryology, we here propose a novel hypothetical model of spinal nerve ramification. Our model is based on the previously unknown developmental process of the intercostal nerves. Observations of these nerves in the mouse embryos revealed that the intercostal nerves initially had superficial and deep ventral branches, which is contrary to the general perception of a single ventral branch. The initial dual innervation pattern later changes into an adult-like single branch pattern following the retraction of the superficial branch. The modified intercostal nerves consist of the canonical ventral branches and novel branches that run on the muscular surface of the thorax, which sprout from the lateral cutaneous branches. We formulated the embryonic branching pattern into the hypothetical ramification model of the human spinal nerve so that the branching pattern is compatible with the developmental context of the target muscles. In our model, every spinal nerve consists of three components: (1) segmental branches that innervate the primaxial muscles, including the dorsal rami, and short branches and long superficial anterior branches from the ventral rami; (2) plexus-forming intramural branches, the serial homolog of the canonical intercostal nerves, which innervate the abaxial portion of the body wall; and (3) plexus-forming extramural branches, the series of novel branches located outside of the body wall, which innervate the girdle and limb muscles. The selective elaboration or deletion of each component successfully explains the reasoning for the standard morphology and variability of the spinal nerve. Therefore, our model brings a novel understanding of spinal nerve development and valuable information for basic and clinical sciences regarding the diverse branching patterns of the spinal nerve.

Upgraded hydrodissection and its safety enhancement in microwave ablation of papillary thyroid cancer: a comparative study

OBJECTIVES

To study the efficacy and safety of an improved hydrodissection protocol based on the perithyroidal fascial space during microwave ablation for papillary thyroid carcinoma (PTC).

METHODS

The data of 341 patients (94 men and 247 women, median age 41 years old, 25%-75% interquartile range 34-53 years old, nodule maximum diameter 0.2-1.9 cm) who underwent microwave ablation for PTC were retrospectively reviewed. Among them, 185 patients underwent traditional hydrodissection and served as a control group, and 156 patients underwent improved hydrodissection based on perithyroidal fascial spaces, constituting the improved group. Improvements in safety were analyzed by comparing complications between the two groups. The characteristics of hydrodissected spaces, complications, and follow-up results were recorded.

RESULTS

Hydrodissection was successfully performed in all enrolled patients according to the protocol. The incidence of hoarseness caused by recurrent laryngeal nerve injury, the most common complication in thermal ablation of thyroid nodules, was significantly lower in the improved group than in the control group (1.9% vs. 8.1%, p = 0.021). The median hoarseness recovery time in the improved group was shorter than that in the control group (2 months vs. 3 months, p = 0.032). During follow-up, no local recurrence was encountered in either group. The tumor disappearance rate was not significantly different between the two groups (69.9% vs. 75.7%, p = 0.228).

CONCLUSIONS

Improved hydrodissection based on perithyroidal fascial spaces had better protective effects than traditional hydrodissection.

The carotid sheath: Anatomy and clinical considerations

Objectives

The distinctive bilateral carotid sheaths (CS) reside in the neck region and form part of the deep cervical fasciae. Aspects of the CS anatomy are controversial, most notably its specific attachment sites and fascial makeup, which are key determinants for the spread of tumours and infections and surgical planning. This review aimed to organise the pertinent aspects relating to CS anatomy and pathology, explore their clinical relevance and highlight areas of disagreement in the literature.

Methods

A narrative review identified key papers relating to CS anatomy, histology, embryology, pathology and clinical and surgical significance using PubMed and Google Scholar. This was supported by a systematic review focused on the fascia forming the CS which was conducted using PubMed, Web of Science and Core Collection which yielded 22 papers.

Results

and Discussion: The CS surrounds the internal carotid artery, internal jugular vein, cranial nerves IX - XII, lymph nodes and nervous plexuses as they course from the jugular foramen superiorly down along into the mediastinum inferiorly. There are contradicting descriptions regarding the CS attachments at the extracranial skull base and within the mediastinum. Author descriptions of the CS fasciae are complex, varied and incongruent. Pathologies affecting the CS include malignancies of the nerves, vascular lesions and utilisation of the CS space as a corridor for the spread of deep neck infections.

Conclusion

This paper collates and presents pertinent anatomical and clinical aspects regarding the CS. A proper knowledge of the CS anatomy and structural relationships will optimise surgical approaches and orientation when operating within the region.

Postoperative Swallowing Function in Patients with Deep Neck Infection

Introduction

Early detection of dysphagia risk, initiating rehabilitation, and resumption of appropriate diet based on swallowing function is important during deep neck infection (DNI) control. This study aimed to evaluate the extent of cervical abscess development, particularly in the deep neck space, and its relationship to postoperative swallowing function.

Methods

A retrospective chart review was performed for all DNI cases treated between April 2015 and April 2021. Deep neck spaces were divided into categories based on computed tomography findings. Functional Oral Intake Scale (FOIS) scores of 4 or higher was defined as normal or slight swallowing disorder and 3 or lower as dysphagia.

Results

Seventeen cases were included in the analysis. Based on FOIS, 14 cases were classified into the dysphagia group at 2 weeks after surgery, 11 cases at 4 weeks, and 8 cases at 8 weeks. There was no significant difference between the location of the abscess and dysphagia at 2 weeks after surgery. Patients with anterior cervical space abscess significantly increased dysphagia 4 weeks (p = 0.018) and 8 weeks (p = 0.036) after surgery.

Conclusion

Abscess formation in the anterior cervical space may be associated with prolonged dysphagia after treatment due to inflammation and scarring of the muscles associated with swallowing.

Imaging assessment of deep neck spaces infections: an anatomical approach

Despite the widespread use of antibiotics, deep neck infections are still a relevant clinical problem and can cause severe and potentially life-threatening complications. Imaging plays a pivotal role into the clinical management of deep neck infections, allowing identification of the source of infections, definition of the precise extension of the disease and early diagnosis of local or distant complications. The complex anatomy of deep neck spaces may hide the actual extent of disease: the knowledge of neck anatomy enables radiologists to rapidly evaluate expected routes of spread of infections and to effectively communicate crucial information to surgeons. Computed Tomography is the most used imaging modality for assessing primary site of infection, extent of disease and local complications. Magnetic resonance imaging may be used as a second level imaging modality for individuating intracranial or spinal complications. The present work aims to review the imaging of deep neck spaces infections, focusing on relevant anatomy and clinical scenarios, underlining practical teaching points for each of them. Familiarity with deep neck spaces anatomy and knowledge of most common routes of spread of infections allow the radiologist to make a prompt diagnosis and to look for early signs of potential complications.

Lymph drainage and cervical fascia anatomy-oriented differential nodal CTV delineation at the supraclavicular region for esophageal cancer and nasopharyngeal cancer

PURPOSE

To determine the differences in supraclavicular lymph node metastasis between esophageal cancer (EC) and nasopharyngeal cancer (NPC) and explore the feasibility of differential supraclavicular clinical target volume (CTV) contouring between these two diseases based on the involvement of different fascial spaces.

MATERIALS AND METHODS

One hundred patients with supraclavicular nodes positive for EC or NPC were enrolled, and their pre-treatment images were reviewed. The distribution patterns of nodes between the two diseases were compared in the context of node levels defined by the 2017 Japanese Esophageal Society and 2013 International Consensus on Cervical Lymph Node Level Classification. Grouping supraclavicular nodes based on sub-compartments formed by the cervical fascia was discussed, and the feasibility of differential CTV contouring based on the differences in the involvement of these sub-compartments between EC and NPC was explored.

RESULTS

The 2013 Consensus on cervical node levels and 2017 Japanese Esophageal Society node station could not practically guide supraclavicular CTV contouring. We divided the supraclavicular space into six sub-compartments: the para-esophageal space (PES), carotid sheath space (CSS), sub-thyroid pre-trachea space (STPTS), pre-vascular space (PVS), and vascular lateral space (VLS) I and II. EC mainly spread to the PES, STPTS, CSS, and VLS I, whereas NPC tended to spread to the CSS, VLS I, and VLS II. These combinations of sub-compartments may help constitute the supraclavicular CTVs for EC and NPC.

CONCLUSIONS

The fascia anatomy-based sub-compartments sufficiently distinguished metastasis to the supraclavicular space between EC and NPC, thus facilitating differential CTV contouring between these two diseases.

The Alar Fascia and Danger Space: A Modern Review

PURPOSE

Given the advancements in dissection modalities over the last decade, what is the current understanding of the alar fascia and its clinical implications as an access point into the danger space (DS)? The aim of the study is to provide an updated review of the alar fascia and danger space.

METHODS

A comprehensive search of the alar fascia and danger space was performed through PubMed databases up to August 2022. Thirty-two sagittal E12 sheet plastination slices of the head and neck were analyzed under a stereomicroscope to assess the morphology and continuity of the retropharyngeal, alar, and prevertebral fasciae (PVF and their respective potential spaces).

RESULTS

Recent advancements have provided evidence that the alar fascia is a true fascial layer between the retropharyngeal and danger spaces within the deep cervical region. Although its composition, histological features, and borders remain topics of controversy, the alar fascia is comprised of dense connective tissue and may serve as a physical barrier to prevent the spread of infection into the danger space. Complications arising from deep neck infections that invade the danger space include mediastinitis, necrotizing fasciitis, and empyema.

CONCLUSION

A proper understanding of the anatomy, structure, function, and potential spaces is crucial to assessing the alar fascia and danger space routinely in clinical practice, especially when imaging.

Paediatric Deep Neck Infection—The Risk of Needing Intensive Care

Deep neck infections are potentially dangerous complications of upper respiratory tract or odontogenic infections. The pathophysiology, clinical presentation, and potential spreading depend on the complex anatomy of the neck fascia. These infections can lead to severe pathological conditions, such as mediastinitis, sepsis, and especially airway impairment with difficult management. Because of the risk of life-threatening emergency situations and the possible impacts on the overall health status of affected children, their early recognition is of utmost importance. Torticollis, drooling, and stridor are the most common signs of advancing disease. Children presenting with these symptoms should be admitted to the paediatric intensive care unit for vital function monitoring, where the airway could be readily secured if function is compromised.

Retropharyngeal, Parapharyngeal and Peritonsillar Abscesses

Deep neck infections (DNIs) include all the infections sited in the potential spaces and fascial planes of the neck within the limits of the deep layer of the cervical fascia. Parapharyngeal and retropharyngeal infections leading to parapharyngeal abscess (PPA) and retropharyngeal abscess (RPA) are the most common. DNIs remain an important health problem, especially in children. The aim of this narrative review is to describe the management of peritonsillar, retropharyngeal and parapharyngeal abscesses in pediatric age. Despite relatively uncommon, pediatric DNIs deserve particular attention as they can have a very severe course and lead to hospitalization, admission to the intensive care unit and, although very rarely, death. They generally follow a mild upper respiratory infection and can initially present with signs and symptoms that could be underestimated. A definite diagnosis can be made using imaging techniques. Pus collection from the site of infection, when possible, is strongly recommended for definition of diseases etiology. Blood tests that measure the inflammatory response of the patient may contribute to monitor disease evolution. The therapeutic approach should be targeted toward the individual patient. Regardless of the surgical treatment, antibiotics are critical for pediatric DNI prognosis. The diagnostic-therapeutic procedure to be followed in the individual patient is not universally shared because it has not been established which is the most valid radiological approach and which are the criteria to be followed for the differentiation of cases to be treated only with antibiotics and those in which surgery is mandatory. Further studies are needed to ensure the best possible care for all children with DNIs, especially in this era of increased antimicrobial resistance.

[Endoscopic transoral retropharyngeal lymphadenectomy]

Objective:The aim of this study is to explore the anatomy and surgical approach of retropharyngeal lymphadenectomy via endoscopic transoral approach. Methods:The retropharyngeal spaces were studied with three fresh frozen cadaver head （6 sides） in the anatomical laboratory of Eye, Ear, Nose and Throat Hospital of Fudan University through endoscopic transoral approach. The superior pharyngeal constrictor muscle, medial pterygoid muscle, tendon of tensor veli palatini muscle, fat of prestyloid space, ascending palatine artery and its branches, styloglossus, stylopharyngeus, stylohyoideus, external carotid artery, levator veli palatini, carotid sheath, ascending pharyngeal artery and longus capitis muscle were revealed in order. The above-mentioned structures were photographed with a 0° Karl Storz nasal endoscope and adjacent relationships were recorded. A case of metastatic retropharyngeal lymphadenopathy was reviewed and the surgical methods and techniques of retropharyngeal lymphadenectomy via endoscopic transoral approach were introduced in detail. Results:The retropharyngeal space and related anatomical structures were exposed through endoscopic transoral approach in all specimens. The styloglossus, stylopharyngius and levator veli palatini are the markers of locating the internal carotid artery. The superior pharyngeal constrictor muscle, medial pterygoid muscle, styloid muscle group, longus capitis muscle and carotid sheath are the markers that can be used to locate the retropharyngeal lymph nodes. Ascending palatine artery, ascending pharyngeal artery and internal carotid artery are the main arteries involved in retropharyngeal lymphadenectomy via endoscopic transoral approach. Conclusion:Endoscopic transoral approach is a new surgical technique to perform retropharyngeal lymphadenectomy safely and completely.

Surgical anatomy of the upper esophagus related to robot-assisted cervical esophagectomy

Robot-assisted cervical esophagectomy (RACE) enables radical surgery for tumors of the middle and upper esophagus, avoiding a transthoracic approach. However, the cervical access, narrow working space, and complex topographic anatomy make this procedure particularly demanding. Our study offers a stepwise description of appropriate dissection planes and anatomical landmarks to facilitate RACE. Macroscopic dissections were performed on formaldehyde-fixed body donors (three females, three males), according to the surgical steps during RACE. The topographic anatomy and surgically relevant structures related to the cervical access route to the esophagus were described and illustrated, along with the complete mobilization of the cervical and upper thoracic segment. The carotid sheath, intercarotid fascia, and visceral fascia were identified as helpful landmarks, used as optimal dissection planes to approach the cervical esophagus and preserve the structures at risk (trachea, recurrent laryngeal nerves, thoracic duct, sympathetic trunk). While ventral dissection involved detachment of the esophagus from the tracheal cartilage and membranous part, the dorsal dissection plane comprised the prevertebral compartment harboring the thoracic duct and right intercosto-bronchial artery. On the left side, the esophagus was attached to the aortic arch by the aorto-esophageal ligament; on the right side, the esophagus was bordered by the azygos vein, right vagus nerve, and cardiac nerves. The stepwise, illustrated topographic anatomy addressed specific surgical demands and perspectives related to the left cervical approach and dissection of the esophagus, providing an anatomical basis to facilitate and safely implement the RACE procedure.

Static Suspension of the Paralyzed Face Utilizing the Midfacial Corridor: Anatomic Evaluation and Surgical Technique

INTRODUCTION

 Fascia lata and tendon grafts are frequently utilized to support the paralyzed midface and to extend muscular reach in McLaughin style, orthodromic temporalis transfers. The grafts are frequently placed in a deep subcutaneous positioning that can lead to the development of a, bowstring deformity in the cheek. This paper describes insertion of tendon grafts into the midfacial corridor collectively formed by the buccal, submasseteric and superficial temporal spaces.

METHODS

 Over a seven-year period, all patients that underwent insertion of facia lata and tendon grafts in the midfacial corridor were included. Demographic information, perioperative variables and clinical outcomes were collected and analyzed.

RESULTS

 A total of 22 patients were included with a mean age of 64.3 years (33-86). There were multiple etiologies for the facial weakness including acoustic neuroma (9.1%), Bell's palsy (13.6%), facial nerve schwannoma (9.1%), temporal bone fracture (4.6%) and malignancy (22.7%). Midfacial corridor grafts were utilized in combination with nerve transfers (V-VII and XII-VII) in nine patients, McLaughin style temporalis transfers in 12 and as a standalone procedure in one individual. During the study period, no patients exhibited a tethering, or concave deformity in the midface. Additionally, no impingement, difficulties with mastication, parotitis or hematoma were encountered. One patient developed a postoperative infection, that was successfully managed.

CONCLUSION

 Placement of tendon or fascia grafts for static support or tunneling of an orthodromic temporalis transfer through the midfacial corridor can be performed rapidly while providing midfacial support and avoiding the creation of visible cutaneous deformities.

Life threatening abscess in the visceral space with penicillin and metronidazole resistant Prevotella Denticola following use of a laryngeal mask airway: case report

Background

Laryngeal mask airways (LMA) are commonly used for airway management. Complications with this device are rare. However, when they do occur, there is a high risk for respiratory problems, necessitating early diagnosis and treatment. We present the first case of a life-threatening abscess spreading in the visceral space caused by a penicillin and metronidazole resistant Prevotella Denticola after the use of an LMA.

Case presentation

A female patient was admitted to our day care centre for bunion surgery. A single use LMA size 3 (Solus®, intersurgical, Wokingham, Berkshire, United Kingdom) was successfully inserted. After surgery, the patient complained of a sore throat and amoxicillin was prescribed by the general practitioner. Three days after surgery the patient was admitted to the Intensive Care Unit (ICU) for obstructive breathing, due to an abscess in the visceral space. Retropharyngeal and certainly parapharyngeal abscesses in adults are already rare. This case however, is unique because it is the first case of abscess spreading into the visceral space after the use of an LMA. Amoxicillin/clavulanate and vancomycin were started. The abscess was incised 5 days later and microbiology showed 3 positive cultures of the anaerobe Prevotella denticola, resistant for penicillin and metronidazole, but sensitive for amoxicillin/clavulanate. The patient fully recovered.

Conclusion

LMA’s are easy to use and are established, safe tools to support ventilation of the airway. In this case, the authors hypothesise a small wound in the lateral pharyngeal wall probably created an opening into the visceral space causing infection with Prevotella denticola, supporting the idea that the pharyngeal mucosal space must be part of the visceral space. Additionally, early recognition and treatment of an LMA induced abscess is necessary to prevent evolution of complications leading to airway obstruction.

Anatomical Continuation Between the Sub-Superficial Musculoaponeurotic System Fat and Retro-Orbicularis Oculi Fat: The True Nature of the Retro-Orbicularis Oculi Fat

Objective: This study aims to analyze the anatomical location and continuation between the retro-orbicularis oculi fat (ROOF) and sub-superficial musculoaponeurotic system fat (subSMAS fat; named "innominate fascia") by comparing their layered structures, thereby letting us suggest a safe minimally invasive procedure guideline for the forehead and temple. Methods: Ultrasonographic scanning was performed from the upper medial eyebrow to the lateral side of the superior temporal line in 109 volunteers. Hematoxylin and eosin staining was performed on five specimens at the same area as ultrasonographic scanning. Then, four embalmed cadavers were dissected from the orbicularis oculi, frontalis muscle, superficial temporal fascia, and SMAS to confirm the location and continuation pattern of the ROOF and subSMAS fat. Results: On ultrasonography and histological images, there was a continuous fatty layer from the ROOF to the subSMAS fat. When dissecting, the ROOF, which was located deep below the frontalis muscle, also continued to the subSMAS fat, passing through the superior temporal line in the upper temporal region. Conclusions: This study confirmed that the subSMAS fat is an anatomical fat structure that is continuous with the ROOF. Since the subSMAS fat layer is known as a less vascular area, it is considered a safer layer to avoid serious complications, and injecting accurately into the subSMAS fat layer has been a goal of clinicians. Based on this study, a cannula will safely approach the subSMAS fat through the ROOF injection that named "forehead-downward approach."

Panoramic Ultrasound Examination of Posterior Neck Extensors in Healthy Subjects: Intra-Examiner Reliability Study

Previous studies analyzing morphometry of posterior cervical muscles with ultrasound (US) imaging have mainly used Brightness mode (B-mode). Our aim was to investigate the intra-examiner reliability of panoramic US imaging for assessing posterior-lateral cervical muscle layers. Panoramic US images of the neck at C4/C5 level were acquired in 25 asymptomatic subjects (40% women; mean age: 24 years) by an experienced assessor. The cross-sectional area (CSA) of the upper trapezius, splenius, semispinalis, multifidi, rotators, and levator scapulae was measured from panoramic US scans on two separate days. Intra-class correlation coefficients (ICC3,1), standard error of measurement (SEM), minimal detectable change (MDC) and mean, absolute and percent errors were calculated. In general, intra-examiner reliability was excellent with ICC3,1 ranging from 0.978 (trapezius) to 0.993 (semispinalis). The SEM ranged from 0.02 (multifidus) to 0.07 (semispinalis/levator), whereas the MDC ranged from 0.05 (cervical multifidus) to 0.19 (levator/semispinalis). Absolute error was lower than 0.11 cm² (levator/semispinalis). No differences between males and females were found. This study found that intra-examiner/rater reliability of panoramic US imaging was excellent for assessing the CSA of the posterior-lateral neck extensor muscles in asymptomatic subjects. The current findings suggest that panoramic US may be a reliable technique for examining the size of the cervical extensor muscles in both males and females.

Anatomical and histological study of the alar fascia

INTRODUCTION

The alar fascia remains one of the most variably described fascial structure in the human body. Much disagreement persists in the literature and mainstream anatomical texts about its anatomy, function, and clinical significance. It is generally described as a coronally oriented fascial sheet separating the retropharyngeal space anteriorly from the danger space posteriorly. The current study aimed to confirm the presence of the alar fascia and delineate its anatomical characteristics, connections, and potential function through gross dissection and microscopic analysis. Possible clinical and surgical implications are considered.

METHODS

Twelve (12) cadaveric necks were dissected and examined histologically. Smooth muscle (αSMA), nerve (S100 protein), and myosin proteins were identified immunohistologically to characterize the composition and possible functions of the alar fascia.

RESULTS

The alar fascia was found in all specimens spanning between the carotid sheaths. Morphologically, it was not a delamination or derivative of the prevertebral fascia. It extended from the base of the skull to the upper thoracic level (T2) where it fused with the visceral fascia. No midsagittal connection was found between the alar and visceral fasciae. Immunohistochemically, the alar fascia was positive in focal areas for αSMA and S100 proteins but negative for fast and slow myosin.

CONCLUSION

The alar fascia is an independent and constant coronal fascial layer between the carotid sheaths. It contains neurovasculature and may limit the spread of retropharyngeal infections into the thorax as well as facilitate normal physiological functions of the cervical viscera.

Incidence of hemi-diaphragmatic paresis after ultrasound-guided intermediate cervical plexus block: a prospective observational study

PURPOSE

An intermediate cervical plexus block (CPB) targets the posterior cervical space between the sternocleidomastoid muscle and the prevertebral fascia. The phrenic nerve descends obliquely on the surface of the anterior scalene muscle beneath the prevertebral fascia after originating from the C3-C5 ventral rami. Therefore, the phrenic nerve can be affected by a local anesthetic during an intermediate CPB, depending on the permeability characteristics of the prevertebral fascia. This study investigated whether an intermediate CPB affects the phrenic nerve, inducing hemidiaphragmatic paresis.

METHODS

In this prospective observational study, 20 patients undergoing single-incision transaxillary robot-assisted right thyroidectomy were enrolled. The intermediate CPB (0.25% ropivacaine 0.2 ml/kg) was performed at the C4-5 intervertebral level carefully, without penetrating the prevertebral fascia, before the patient emerged from general anesthesia. Diaphragmatic motions of the block side were measured by M-mode ultrasonography at three time points: before anesthesia (baseline) and at 30 and 60 min after the intermediate CPB. Hemidiaphragmatic paresis was divided into three grades, depending on the percentage of diaphragm movement compared to the baseline: none (> 75%), partial paresis (25-75%), and complete paresis (< 25%).

RESULTS

No patient showed any partial or complete ipsilateral hemidiaphragmatic paresis within 60 min after the intermediate CPB.

CONCLUSION

Intermediate CPB using 0.2 ml/kg of 0.25% ropivacaine at the C4-5 intervertebral level did not cause ipsilateral hemidiaphragmatic paresis. This may imply that the effect of the intermediate CPB on the phrenic nerve is not significant.

The intercarotid or alar fascia, other cervical fascias, and their adjacent spaces - a plea for clarification of cervical fascia and spaces terminology

Due to varying descriptions and terminology of fascias of the neck, medical advice relying on this basic knowledge is insufficient. Our goal was to provide a precise anatomical description of cervical fascias and spaces with special focus on the intercarotid fascia, or the alar fascia. One hundred bodies donated to science embalmed with Thiel's method were investigated, cervical fascias were dissected layer by layer, and the results were documented by photography, with a focus on the intercarotid fascia. In addition, we performed a review of recent literature concerning cervical surgical interventions, radiological diagnostic pathways, and basic anatomical works focusing on core information on anatomical relations of cervical fascias and spaces. In another 10 bodies donated to science, the spaces of the neck were injected with coloured latex under ultrasound guidance, dissected, and documented by photography. The intercarotid fascia was a constantly developed connective tissue interconnecting the carotid sheath of both sides. In 52 of 100 specimens (52%) it crossed to the opposite side without any fusion to the ventrally situated visceral fascia. Fusion with the visceral fascia was found in 48%, either at the lateral border of the pharynx or on its dorsal side. The results of our dissections strengthen the precise description of the cervical fascias provided by Grodinsky and Holyoke in 1938. Spaces can be confirmed as described by Hafferl in 1969. The international anatomical and ENT societies should codify a unified anatomical terminology of the cervical spaces and fascias to prevent varying interpretations in the future.

Comparison of ultrasound-guided intermediate vs subcutaneous cervical plexus block for postoperative analgesia in patients undergoing total thyroidectomy: A randomised double-blind trial

Background and Aims:

Intermediate cervical plexus block (CPB) is a new procedure whose analgesic efficacy compared to superficial cervical plexus block is yet to be established. We compared the analgesic efficacy of superficial vs intermediate CPB for post-operative analgesia after thyroid surgery.

Methods:

Forty-five patients with American Society of Anaesthesiologists' physical status 1 or 2 undergoing total thyroidectomy were recruited. Forty-four patients in superficial/subcutaneous CPB group (n = 22) and intermediate CPB (n = 22) received 20 mL 0.25% bupivacaine with adrenaline 100 μg bilaterally in ultrasound-guided superficial and intermediate cervical plexus block before induction of general anaesthesia., respectively. The primary outcome measure was the postoperative visual analogue scale (VAS) scores at 0, 2, 4, 6, 12 and 24. Secondary outcome measures included the total dose of rescue analgesic required, duration of postoperative analgesia and patient's satisfaction score. Statistical analysis was with the Mann-Whitney U test and independent t-test.

Results:

The post-operative VAS scores were lower in intermediate CPB group compared to superficial CPB group at 2, 4, 6, 12, 18 and 24 h [P < 0.05]. Time tofirst rescue analgesic demand was prolonged 10.06 ± 3.62 h in intermediate group compared to 7.94 ± 3.62 h in superficial group [P = 0.017] and total analgesic consumption were lower in intermediate group (71.25 ± 16.70 μg) than the superficial group (101.25 ± 50.31 μg) [P = 0.011].

Conclusion:

Ultrasound-guided intermediate CPB reduces post-operative pain scores, prolongs duration of analgesia and decreases demands for rescue analgesia compared to superficial CPB.

Early stages of development of the alar fascia (human specimens at 6-12 weeks of development)

In recent years, there has been much discussion concerning the cervical fasciae. The aim of this study is to confirm and to describe the development of the alar fascia as well as its relationship with nearby structures. Histological preparations of 25 human embryos (6-8 weeks of development) and 25 human fetuses (9-12 weeks of development) were studied bilaterally using a conventional optical microscope. Our study confirms the existence of the alar fascia and permits three stages to be established during its development. The initial stage (1st), corresponding to the 6th week of development (Carnegie stages 18-19), is characterized by the beginning of the alar fascia primordium in the retroesophageal space at the level of C7-T1. In the formation stage (2nd), corresponding to the 7th and 8th weeks of development (Carnegie stages 20-23), the alar fascia primordium grows upwards and reaches the level of C2-C3. In the maturation stage (3rd), beginning in the 9th week of development, the visceral, alar and prevertebral fasciae can be identified. The alar fascia divides the retrovisceral space (retropharyngeal and retroesophageal) into two spaces: one anterior (between the alar fascia and the visceral fascia and extending from C1 to T1, named retropharyngeal or retroesophageal space according to the level) and the other posterior (between the alar fascia and the prevertebral fascia, named danger space). We suggest that this latter space be named the retroalar space. This study suggests that alar fascia development is related to mechanical factors and that the alar fascia permits the sliding of the pharynx and the oesophagus during swallowing.

Cervical plexus block

Cervical plexus blocks (CPBs) have been used in various head and neck surgeries to provide adequate anesthesia and/or analgesia; however, the block is performed in a narrow space in the region of the neck that contains many sensitive structures, multiple fascial layers, and complicated innervation. Since the intermediate CPB was introduced in addition to superficial and deep CPBs in 2004, there has been some confusion regarding the nomenclature and definition of CPBs, particularly the intermediate CPB. Additionally, as the role of ultrasound in the head and neck region has expanded, CPBs can be performed more safely and accurately under ultrasound guidance. In this review, the authors will describe the methods, including ultrasound-guided techniques, and clinical applications of conventional deep and superficial CPBs; in addition, the authors will discuss the controversial issues regarding intermediate CPBs, including nomenclature and associated potential adverse effects that may often be neglected, focusing on the anatomy of the cervical fascial layers and cervical plexus. Finally, the authors will attempt to refine the classification of CPB methods based on the target compartments, which can be easily identified under ultrasound guidance, with consideration of the effects of each method of CPB.

[Surgical treatment of acute mediastinitis]

Despite modern intensive care management, acute mediastinitis is still associated with a high morbidity and mortality (up to approximately 40 %). Effective antibiotic therapy, intensive care management, elimination of the causative sources of infection and drainage of the affected mediastinal compartments are the cornerstones of therapy in a multidisciplinary treatment concept. Early diagnosis, prompt and uncompromising initial therapy and planned computed tomography (CT) control after the first stages of therapy in order to decide on the necessity for surgical re-interventions are essential for achieving optimal results. Knowledge of the specific anatomical characteristics is crucial for the understanding of this disease and its treatment; therefore, the current knowledge on fascial layers and interstitial spaces from the neck to the mediastinum is described and discussed. A possible foudroyant spread of the infection, especially within the posterior mediastinum, has to be anticipated. The approach to the mediastinum depends on the mediastinal compartments affected, on the causative disease and on the patient's clinical situation. The surgical approach should be adapted to the particular clinical situation of the individual patient and to the surgical experience of the surgeon. When in doubt, the more invasive approach to the mediastinum, such as bilateral thoracotomy, is recommended. An ascending mediastinitis due to pancreatitis is a very rare condition; however, as chest pains are often the main clinical sign surgeons should be aware of this differential diagnosis. An intraoperative brown-black serous fluid in the mediastinal tissue is virtually pathognomonic. The treatment results of esophageal perforation as the most frequent cause of mediastinitis have been improved by integration of various interventional procedures. Hyperbaric oxygen therapy or immunoglobulin treatment can play an auxiliary role in selected patients with acute mediastinitis.

Is the buccal compartment a masticatory space extension or an anatomic space in itself? Evidence based on medical images and human cadaver dissection

OBJECTIVES

According to some authors, the buccal space is incompletely closed with no real anatomical separation from the masticator space, and also has no fascial limit toward the cranial and caudal regions. However, several other authors consider this anatomic area to be a separated space. The goal of this study was to provide a detailed description of the normal anatomy using medical images and human cadaveric head material dissection of this facial anatomic region, to precisely clarify its condition as an extension of the masticator space or an independent space.

METHODS

The buccomasseteric area in 25 male and female patients aged 14-68 years, who were referred for various head and neck disorders that did not compromise the masticatory and buccal area, was analyzed by magnetic resonance imaging on the axial and coronal planes. The region was further examined by dissection of the buccomasseteric area in four heads of fresh adult male and female human cadavers aged 30-65 years.

RESULTS

The findings demonstrated that the buccal compartment should be considered part of the masticator space, rather than a space in itself. This was mainly because a corridor was positioned medially to the tendon of the masseter muscle that communicated the infratemporal region of the masticator space with the buccal region, with no fascial barrier at this level that could separate it from the masticator space.

CONCLUSIONS

The present study suggests that the buccal compartment is part of the masticator space, rather than a space in itself.

The peri-esophageal connective tissue layers and related compartments: visualization by histology and magnetic resonance imaging

An organized layer of connective tissue coursing from aorta to esophagus was recently discovered in the mediastinum. The relations with other peri-esophageal fascias have not been described and it is unclear whether this layer can be visualized by non-invasive imaging. This study aimed to provide a comprehensive description of the peri-esophageal fascias and determine whether the connective tissue layer between aorta and esophagus can be visualized by magnetic resonance imaging (MRI). First, T2-weighted MRI scanning of the thoracic region of a human cadaver was performed, followed by histological examination of transverse sections of the peri-esophageal tissue between the thyroid gland and the diaphragm. Secondly, pretreatment motion-triggered MRI scans were prospectively obtained from 34 patients with esophageal cancer and independently assessed by two radiologists for the presence and location of the connective tissue layer coursing from aorta to esophagus. A layer of connective tissue coursing from the anterior aspect of the descending aorta to the left lateral aspect of the esophagus, with a thin extension coursing to the right pleural reflection, was visualized ex vivo in the cadaver on MR images, macroscopic tissue sections, and after histologic staining, as well as on in vivo MR images. The layer connecting esophagus and aorta was named 'aorto-esophageal ligament' and the layer connecting aorta to the right pleural reflection 'aorto-pleural ligament'. These connective tissue layers divides the posterior mediastinum in an anterior compartment containing the esophagus, (carinal) lymph nodes and vagus nerve, and a posterior compartment, containing the azygos vein, thoracic duct and occasionally lymph nodes. The anterior compartment was named 'peri-esophageal compartment' and the posterior compartment 'para-aortic compartment'. The connective tissue layers superior to the aortic arch and at the diaphragm corresponded with the currently available anatomic descriptions. This study confirms the existence of the previously described connective tissue layer coursing from aorta to esophagus, challenging the long-standing paradigm that no such structure exists. A comprehensive, detailed description of the peri-esophageal fascias is provided and, furthermore, it is shown that the connective tissue layer coursing from aorta to esophagus can be visualized in vivo by MRI.

SMAS Fusion Zones Determine the Subfascial and Subcutaneous Anatomy of the Human Face: Fascial Spaces, Fat Compartments, and Models of Facial Aging

BACKGROUND

Fusion zones between superficial fascia and deep fascia have been recognized by surgical anatomists since 1938. Anatomical dissection performed by the author suggested that additional superficial fascia fusion zones exist.

OBJECTIVES

A study was performed to evaluate and define fusion zones between the superficial and the deep fascia.

METHODS

Dissection of fresh and minimally preserved cadavers was performed using the accepted technique for defining anatomic spaces: dye injection combined with cross-sectional anatomical dissection.

RESULTS

This study identified bilaminar membranes traveling from deep to superficial fascia at consistent locations in all specimens. These membranes exist as fusion zones between superficial and deep fascia, and are referred to as SMAS fusion zones.

CONCLUSIONS

Nerves, blood vessels and lymphatics transition between the deep and superficial fascia of the face by traveling along and within these membranes, a construct that provides stability and minimizes shear. Bilaminar subfascial membranes continue into the subcutaneous tissues as unilaminar septa on their way to skin. This three-dimensional lattice of interlocking horizontal, vertical, and oblique membranes defines the anatomic boundaries of the fascial spaces as well as the deep and superficial fat compartments of the face. This information facilitates accurate volume augmentation; helps to avoid facial nerve injury; and provides the conceptual basis for understanding jowls as a manifestation of enlargement of the buccal space that occurs with age.

The equine neck and its function during movement and locomotion

During both locomotion and body movements at stance, the head and neck of the horse are a major craniocaudal and lateral balancing mechanism employing input from the visual, vestibular and proprioceptive systems. The function of the equine neck has recently become the focus of several research groups; this is probably also feeding on an increase of interest in the equine neck in equestrian sports, with a controversial discussion of specific neck positions such as maximum head and neck flexion. The aim of this review is to offer an overview of new findings on the structures and functions of the equine neck, illustrating their interplay. The movement of the neck is based on intervertebral motion, but it is also an integral part of locomotion; this is illustrated by the different neck conformations in the breeds of horses used for various types of work. The considerable effect of the neck movement and posture onto the whole trunk and even the limbs is transmitted via bony, ligamentous and muscular structures. Also, the fact that the neck position can easily be influenced by the rider and/or by the employment of training aids makes it an important avenue for training of new movements of the neck as well as the whole horse. Additionally, the neck position also affects the cervical spinal cord as well as the roots of the spinal nerves; besides the commonly encountered long-term neurological effects of cervical vertebral disorders, short-term changes of neural and muscular function have also been identified in the maximum flexion of the cranial neck and head position. During locomotion, the neck stores elastic energy within the passive tissues such as ligaments, joint capsules and fasciae. For adequate stabilisation, additional muscle activity is necessary; this is learned and requires constant muscle training as it is essential to prevent excessive wear and tear on the vertebral joints and also repetitive or single trauma to the spinal nerves and the spinal cord. The capability for this stabilisation decreases with age in the majority of horses due to changes in muscle tissue, muscle coordination and consequently muscle strength.

Is the cervical fascia an anatomical proteus?

The cervical fasciae have always represented a matter of debate. Indeed, in the literature, it is quite impossible to find two authors reporting the same description of the neck fascia. In the present review, a historical background was outlined, confirming that the Malgaigne's definition of the cervical fascia as an anatomical Proteus is widely justified. In an attempt to provide an essential and a more comprehensive classification, a fixed pattern of description of cervical fasciae is proposed. Based on the morphogenetic criteria, two fascial groups have been recognized: (1) fasciae which derive from primitive fibro-muscular laminae (muscular fasciae or myofasciae); (2) fasciae which derive from connective thickening (visceral fasciae). Topographic and comparative approaches allowed to distinguish three different types of fasciae in the neck: the superficial, the deep and the visceral fasciae. The first is most connected to the skin, the second to the muscles and the third to the viscera. The muscular fascia could be further divided into three layers according to the relationship with the different muscles.

Clinical and symptomatological reflections: the fascial system

Every body structure is wrapped in connective tissue, or fascia, creating a structural continuity that gives form and function to every tissue and organ. Currently, there is still little information on the functions and interactions between the fascial continuum and the body system; unfortunately, in medical literature there are few texts explaining how fascial stasis or altered movement of the various connective layers can generate a clinical problem. Certainly, the fascia plays a significant role in conveying mechanical tension, in order to control an inflammatory environment. The fascial continuum is essential for transmitting muscle force, for correct motor coordination, and for preserving the organs in their site; the fascia is a vital instrument that enables the individual to communicate and live independently. This article considers what the literature offers on symptoms related to the fascial system, trying to connect the existing information on the continuity of the connective tissue and symptoms that are not always clearly defined. In our opinion, knowing and understanding this complex system of fascial layers is essential for the clinician and other health practitioners in finding the best treatment strategy for the patient.