副神経の内頚静脈貫通例の経験

CHAPTER 17 - Radical Neck Dissection

We read with interest the article entitled Retroauricular Video-Assisted ‘‘Gasless’’ Thyroidectomy: Feasibility Study in Human Cadavers [1]. This article describes a new ‘‘distant access’’ minimally invasive surgical approach to the thyroid gland. The article presents for the first time the retroauricular hairline incision approach to the thyroid gland using the endoscopic assistance gasless technique. The proposed technique allowed hemithyroidectomy to be performed through an 11.8 ± 1.2-cm incision [2] in six human cadavers. In our opinion, the surgical technique described by the authors is limited to hemithyroidectomy. Total thyroidectomy could be performed through a bilateral retroauricular access. We think the 11.8 ± 1.2-cm incision is quite large for a video-assisted approach to the thyroid gland and that a double-size incision due to the bilateral approach is not justified for a total thyroidectomy. This extensive access is not justified for either minimally invasive surgery or open surgery. Kocher’s cervicotomy, video-assisted thyroidectomy (VAT), and minimally invasive video-assisted thyroidectomy (MIVAT) remain the best options for thyroidectomy or parathyroidectomy. A surgical access far from the targeted organ can increase the risk of infection and can damage important structures not identified in reaching the thyroid gland. The described procedures entail an increased risk of damage to the great auricular nerve, lesser occipital nerve, facial nerve, accessory nerve, hypoglossal nerve, digastrics muscle, styloyoid muscle, internal jugular vein, external carotid artery, phrenic nerve, and vagus nerve. The risk of infection also is increased due to the proximity of the incision to less clean areas of the body (ear and hair). Because of the high increased risks added with this procedure, we think the most important thing in surgery is primum non nocere, deinde philosophare (do not harm first, philosophize later). The authors mention that the end point of the study was to achieve gland resection with identification and preservation of the recurrent laryngeal nerve. Because the study was conducted with human cadavers, preservation of the nerve could not be identified with certainty. The authors have recorded 100% success in a cold, bloodless setting, but we know that every time the camera is moved, the risk of causing damage to important anatomic structures is increased [3], especially with the gasless technique. The authors mention two added complications: dysthesia of the earlobe and alopecia at the incision site. These complications preclude the good cosmetic results they mention as an end point desired by the patient. To achieve good cosmetic results, plastic surgery after a classic Kocher’s cervicotomy would be more appropriate. In fact, the authors have written that ‘‘overall patient satisfaction with the resultant scar on a visual analogue scale was significantly higher in patients in the retroauricular cohort as compared with patients having a traditional cervical incision’’ [2]. This underscores the importance of the cosmetic result for the patient, but the citation is incorrect because in the mentioned study, the authors compare a lateral neck upper incision with retroauricular access. Therefore, it is not possible to know whether the patient prefers a classic G. Galata (&) M. Mulla Department of Surgery, King’s College Hospital, NHS Foundation Trust, Denmark Hill, London SE5 9RS, UK e-mail: g.galata@libero.it

The major complication of neck dissection and surgery at the posterior triangle of the neck is the shoulder syndrome, which results from spinal accessory nerve injury. Erb's point (the great auricular nerve) and the point where the spinal accessory nerve enters the trapezius muscle are used to identify the spinal accessory nerve in the posterior nerve triangle. Measurements were made during unilateral neck dissections in 30 patients to identify the relationship between the spinal accessory nerve and great auricular nerve and the distance between the entrance of the accessory nerve in the trapezious and clavicle. The distance between the spinal accessory nerve and Erb's point was ranging from 0 to 3.8 cm (mean 1.53 cm). The distance between the spinal accessory nerve entering the trapezious muscle and the clavicle was between 2.5 and 7.3 cm (mean 4.8 cm). Since the great auricular nerve (Erb's point) represents a constantly identifiable landmark, it allows simple and reliable identification of the course of the spinal accessory nerve. Also useful, but of secondary importance in our opinion, is identifying the nerve at the point where it enters the trapezius muscle.

Background: In a clinical situation, such as in the interventional treatment for spasmodic torticollis patients, a conventional approach for accessory nerve blockade can not assure blockade of the accessory nerve (XI) branch supplying the sternocleidomastoid muscle (SCM). Therefore, a new approach, which can block the XI branch to the SCM or main XI nerve, is required. Methods: Two fresh frozen cadavers were prepared in the prone position, and then slightly rotated to the blockaded side. Thereafter, 10 ml of a natural liquid rubber and barium hydroxide mixture (2 : 1) was injected underneath the SCM, through the entry point at the posterior border junction of the upper and middle thirds (conventional method) successively in each cadaver. The inferior mastoidal, just lateral to the styloid process approach to the compartment, in which the accessory nerve, internal jugular vein, hypoglossal nerve, vagus nerve, glossopharyngeal nerve, sympathetic trunk and internal carotid artery stay, was threaded with a block needle and 10 ml of the natural liquid rubber and barium hydroxide mixture (2 : 1) (new method) successively injected in each cadaver. Computed tomography (CT) was performed on all specimens. Three-dimensional reconstruction and morphometry of the new and conventional approach were also performed using the V-workstm (version 4.0) program. Results: In both cadavers, the conventional method show no spread of the natural liquid rubber and barium hydroxide mixture (2 : 1) to the XI branch for the SCM or proximal main XI nerve. However, the new method show good spread of the natural liquid rubber and barium hydroxide mixture (2 : 1) to the XI branch for the SCM or proximal main XI nerve in both cadavers. Conclusions: With this new approach, it is possible to confirm a compartmental space, which can then be used for the administration of local anesthetics, which can then block the XI branch for the SCM or main XI nerve.

The accessory nerve is traditionally described as having both spinal and cranial roots, with the spinal root originating from the upper cervical segments of the spinal cord and the cranial root originating from the dorsolateral surface of the medulla oblongata. The spinal rootlets and cranial rootlets converge either before entering the jugular foramen or within it. In a recent report, this conventional view has been challenged by finding no cranial contribution to the accessory nerve. The present study was undertaken to re-examine the accessory and vagus nerves within the cranium and jugular foramen, with particular emphasis on the components of the accessory nerve. These nerves were traced from their rootlets attaching to the spinal cord and the medulla and then through the jugular foramen. The jugular foramen was exposed by removing the dural covering and surrounding bone. A surgical dissecting microscope was used to trace the roots of the glossopharyngeal nerve (CN IX), vagus nerve (CN X) and accessory nerve (CN XI) before they entered the jugular foramen and during their travel through it. The present study demonstrates that the accessory nerve exists in two forms within the cranial cavity. In the majority of cases (11 of 12), CN XI originated from the spinal cord with no distinct contribution from the medulla. However, in one of 12 cases, a small but distinct connection was seen between the vagus and the spinal accessory nerves within the jugular foramen.

Background and Objectives: The symptoms of Eagle’s syndrome are associated with the elongated styloid process of the temporal bone or calcification of the stylohyoid ligament. The first mention of pain syndrome associated with the elongated styloid process dates back to 1937, when it was described by Watt Weems Eagle. Over the last decade, experts in the field have shown a lively interest in the issue of the relationship between the elongated styloid process and various symptoms. This article presents the correlation between the clinical signs of Eagle’s syndrome and alterations in surrounding anatomical structures. It includes a brief review of the evolutionary, embryological and clinical anatomical background of the elongated styloid process. Materials and Methods: Between 2018 and 2019, five patients were admitted to our workplace with 1–3-year history of bilateral or unilateral throat pain, otalgia and pharyngeal foreign body sensation. As a therapeutic novelty in the surgical approach to this condition, we used individual 3D printed models to measure and identify the exact location of the resection of the styloid process without damaging the surrounding anatomical structures, such as the facial, accessory, hypoglossal, and vagal nerves; the internal jugular vein; and the internal carotid artery. Results: Compared to traditional surgical methods without 3D models, 3D models helped to better identify cutting edges and major landmarks used in surgical treatment of Eagle’s syndrome. Printed models provided assistance with the exact location of the styloid process resection position without damaging the surrounding anatomical structures such as the facial, accessory, hypoglossal, and vagal nerves; the internal jugular vein; and the internal carotid artery. Conclusion: In our clinical report, we used 3D printed models for navigation and planning during surgical procedures involving resections of the elongated styloid process. Additionally, we can formulate a new hypothesis: the elongated styloid process is a form of atavism of the bony hyoid apparatus in our evolutionary ancestors that is evolutionarily encoded or arises from disrupted degeneration of the middle portion of embryonal Reichert´s cartilage of the second pharyngeal arch. Under normal conditions, this portion does not ossify but degenerates and transforms into a connective tissue band, the future stylohyoid ligament.

The X-pointer: A forgotten anatomical relationship of spinal accessory nerve and great auricular nerve

Internal Jugular Vein Duplication: Anatomic Relationship With the Spinal Accessory Nerve

Lateral neck dissection (LND) leads to a significant morbidity involving accessory nerve injury. Modified radical neck dissection (MRND) aims at preservation of the accessory nerve, but patients often present with negative functional outcomes after surgery. The role of neuromonitoring (IONM) in the prevention of shoulder syndrome has not yet been defined in comparison to nerve visualization only. We retrospectively analyzed 56 thyroid cancer patients who underwent MRND over a period of six years (2015–2020) in a high-volume institution. Demographic variables, type of surgical procedure, removed lymph nodes and the metastatic node ratio, pathology, adoption of IONM and shoulder functional outcome were investigated. The mean number of lymph nodes removed was 15.61, with a metastatic node ratio of 0.2745. IONM was used in 41.07% of patients, with a prevalence of 68% in the period 2017–2020. IONM adoption showed an effect on post-operative shoulder function. There were no effects in 89.29% of cases, and temporary and permanent effects in 8.93% and 1.79%, respectively. Confidence intervals and two-sample tests for equality of proportions were used when applicable. Expertise in high-volume centres and IONM during MRND seem to be correlated with a reduced prevalence of accessory nerve lesions and limited functional impairments. These results need to be confirmed by larger prospective randomized controlled trials.

Neck dissection remains the standard method of treating cervical metastasis from head and neck squamous cell carcinoma. In light of recent trends to modify the classic radical neck dissection (RND) for early neck disease, we reviewed our experience with radical and modified RND (MRND) plus radiotherapy as treatment for N2/N3 neck disease in head and neck squamous cell carcinoma. We retrospectively reviewed our clinical records from July 1989 to June 1996 to identify 43 neck dissections in 39 patients who were found to have pathologically N2 or N3 neck disease treated primarily by neck dissection and postoperative radiotherapy. All patients had head and neck squamous cell carcinoma with a minimum follow-up of 24 months. Nine percent (4/43) of the dissected necks were pathologically N2a, 72% (31/43) were N2b, 7% (3/43) were N2c, and 12% (5/43) were N3. Of these, 28% (12/43) underwent a RND and 72% (31/43) underwent a MRND. The most common modification of RND was preservation of the spinal accessory nerve. All patients underwent postoperative radiotherapy with a mean dose of 55 Gy. Only 4 of 43 dissected necks had isolated treatment failure, for a regional control rate of 91%. The combination of RND or MRND and radiotherapy is highly effective in controlling neck disease in the absence of persistent or recurrent local disease. Also, in our experience, MRND appears to be as effective as RND in controlling even advanced neck disease, which supports preservation of the spinal accessory nerve whenever oncologically feasible.

The spinal accessory nerve (SAN) is crucial for the motor function of the trapezius and sternocleidomastoid muscles, playing a significant role in scapular stability and upper limb mobility. While SAN injuries are commonly associated with iatrogenic causes such as lymph node biopsies, neck dissections, and posterior cervical trauma, injury following trapezius lipoma resection has not been well-documented. Given the SAN's superficial location and proximity to surgical fields in the posterior cervical triangle, it is vulnerable to inadvertent injury during tumor excision. To the best of our knowledge, this case report presents the first documented instance of isolated SAN mononeuropathy following trapezius lipoma resection and underscores the importance of early recognition, diagnosis, and management. A 54-year-old male developed SAN mononeuropathy following an elective surgical removal of a deep right-sided trapezius lipoma. One week following resection, the patient exhibited new-onset paresthesias in the right upper extremity, scapular dyskinesis, shoulder weakness, and lateral scapular winging. Prior electrodiagnostic (EDX) studies for different complaints showed no signs of peripheral nerve injury. Given the new presentation, repeat EDX were performed six months postoperatively, revealing severe focal SAN neuropathy with ongoing active denervation. The findings suggest direct or traction-related SAN injury rather than an isolated muscular pathology. Given the course of symptoms, a referral to a peripheral nerve surgeon was warranted for recommendations regarding further management. SAN mononeuropathy following lipoma resection is an important and uncommon complication. Most SAN injuries result from iatrogenic causes, such as neck dissections and lymph node biopsiesor lateral neck trauma. The SAN's close proximity to the surgical site makes it susceptible to iatrogenic injury in posterior cervical triangle procedures. This case highlights the importance of identifying lipoma location and recognizing subtle nerve injuries often overlooked without thorough postoperative assessment. Clinical signs include lateral scapular winging during active external rotation, vague shoulder pain, limitations in range of motion, and potential muscle atrophy.In this case, resection of a deeply situated trapezius lipoma led to SAN dysfunction within one week of surgery. Clinical suspicion, combined with examination and confirmation through EDX, highlights the SAN's vulnerability in this region. SAN injury outcomes vary widely, with treatment options ranging from conservative management to surgical interventions such as nerve grafting, nerve repair, or Eden-Lange muscle transfer. Successful recovery is more likely when repairs are performed early, ideally within seven months, with poorer results after 20 months. This case emphasizes the potential for SAN injury during deep trapezius lipoma resection. Early recognition through physical exam and EDX is essential for distinguishing SAN mononeuropathy from other shoulder dysfunctions, as prompt diagnosis improves functional outcomes. Additionally, preoperative nerve mapping is crucial when operating near critical neural structures, stressing the importance of intraoperative nerve monitoring to reduce the risk of injury. Further research is needed to better understand SAN injury incidence in posterior cervical and scapular surgeries and to develop standardized management guidelines.

ABSTRACTA patient with squamous cell carcinoma of right retromolar area of the mandible and undergoing a staging neck dissection was noted to have a unique relationship of the internal jugular vein and spinal accessory nerve. At the upper end of the dissection (level II, Memorial Sloan-Kettering classification), the spinal accessory nerve was observed to pass directly through the internal jugular vein. Although previously described only once in the literature, this finding may be encountered by other surgeons who operate in this area and it is important that these anatomical variations are borne in mind to prevent inadvertent injury. To our knowledge, this must be the first case reported from India.How to cite this articleDhawan A, Duggal P, Sandhu S. A Rare Anatomical Relationship of Spinal Accessory Nerve to Internal Jugular Vein. Int J Head and Neck Surg 2012;3(1): 40-41.

We present three cases of duplicated or fenestrated internal jugular veins in patients undergoing neck dissection, including the first known case of concomitant bovine aortic arch. The prevalence of this anomaly is 1.0% (three out of 295 patients). Internal jugular vein duplication and fenestration may risk iatrogenic injury to the vasculature and spinal accessory nerve during neck dissection. The existence of this anatomic abnormality should be considered when variation of the internal jugular vein is encountered. The objective of this report is to discuss the presentation, clinical implications, and literature pertaining to internal jugular vein duplication and fenestration. Laryngoscope, 126:1585-1588, 2016.

A Clear Map of the Lower Cranial Nerves at the Superior Carotid Triangle

ObjectiveWe propose a standardized approach of using the tendon of the sternocleidomastoid (SCM) muscle to locate the spinal accessory nerve (SAN) in neck dissection.Study DesignCross-sectional anatomic study.SettingTertiary academic medical center.MethodsAdult patients aged ≥18 years undergoing primary neck dissection for head and neck cancer were included. Anatomic measurements included the length of the SCM tendon, the distance from the mastoid tip to the entrance of the SAN into the SCM, the distance from the SAN to the distal edge of the SCM tendon, and the perpendicular distance from the anterior edge of the SCM to the SAN. Five cadaveric specimens also underwent bilateral modified radical neck dissections with the same anatomic measurements taken.ResultsTwenty-two living subjects and 5 cadavers were included. No statistical correlation was noted between patient demographics and any measurement. The mean (SD) length of the SCM tendon was 63.7 mm (11.8) in living subjects and 61.5 mm (10.4) in cadaveric specimens. The average distance from the mastoid tip to the entrance of SAN into the SCM was 51.6 mm (12.2) in living subjects and 51.6 mm (7.1) in cadaveric subjects. The distance of the SAN insertion into the SCM muscle from the anterior edge was 8.9 mm (3.4) in living subjects and 16.2 mm (7.2) in cadaver specimens. Laterality was compared in the cadaveric specimens; there was no statistically significant difference in any of the measurements between sides.ConclusionThis study demonstrates the SCM tendon to be a reliable and safe surgical landmark to identify and preserve the SAN during neck dissection.