C7 Transverse Process Research Articles

High definition ultrasound imaging of the individual elements of the brachial plexus above the clavicle

Background and objectivesUltrasonography of the brachial plexus (BP) has been described but there are limited data on visualization of the T1 ventral ramus and the inferior trunk. This prospective observational...

The Inferior Nuchal Line as a Simple Landmark for Identifying the Vertebral Artery During the Retrosigmoid Approach.

The V3 segment of the vertebral artery (V3-VA) is at risk during various approaches to the craniovertebral junction. Several landmarks have been defined to identify V3-VA, but these landmarks are not routinely exposed during a retrosigmoid (RS) approach, where musculocutaneous dissection inferiorly towards the foramen magnum can threaten this arterial segment. To find a landmark that will identify the V3-VA during the RS approach, and analyze the inferior nuchal line (INL) as this novel landmark. The anatomic relationships between the INL and the V3-VA were assessed in 7 cadaveric heads through RS exposure in the lateral position. The INL is an L-shaped bony ridge with horizontal (medial) and vertical (lateral) arms, with the vertical arm being more conspicuous in all specimens (INLV). The mean depths of the V3-VA relative to the medial and lateral ends of the INLV were (mean±standard deviation) 24.9±7.1 mm, and 8.3±3.2 mm, respectively. In all specimens, the V3-VA was located inferior and anterior to the INLV. The INL provides an important landmark during RS approach that can protect the V3-VA from inadvertent injury or identify it for use in an interpositional bypass. The INLV identifies the region of the suboccipital triangle where the V3-VA is embedded. INLV is routinely seen during the RS approach, making it more relevant than other classic landmarks such as the transverse process of C1, C1 posterior arch, and the atlantomastoid line that are not exposed during the RS approach.

Ultrasound tour of the anterior neck for the interventional pain physician

Ultrasound tour of the anterior neck for the interventional pain physician

Resection of a Neuroenteric Cyst Using a Far Lateral Approach.

This operative video highlights a rare case of a neuroenteric cyst at the ventral craniocervical junction. The case involved a 30-year-old man who initially presented 13 years earlier with acute onset of headache and visual changes. At that time, he was found to have a small, enhancing ventral intradural extramedullary mass at the rostral aspect of C1 thought to be a meningioma. The lesion was managed conservatively, and surveillance imaging tracked its slow progressive enlargement to a size of 1.4 cm ( Fig. 1A, B ). Although he remained asymptomatic, nonurgent elective resection was recommended because of his age and mass progression. The patient underwent a left far lateral approach to the craniocervical junction for resection of the mass. This involved dissection of the suboccipital musculature to expose the C1 transverse process in the suboccipital triangle and ultimately the vertebral artery. After a small craniectomy and C1 hemilaminectomy, the dura was opened and a cystic lesion encountered ( Fig. 2 ). The cystic contents were debulked and the capsule resected. Histopathologic examination revealed abundant goblet cells consistent with a neuroenteric cyst. Dural closure was bolstered with fascia lata and autologous fat graft. Postoperative magnetic resonance imaging (MRI) was consistent with gross total resection ( Fig. 1C, D ). The patient tolerated the procedure well with no new postoperative neurological deficits and was discharged home on postoperative day 2. On completing a 3-day decadron taper, he developed steroid-responsive symptoms consistent with aseptic meningitis, possibly related to cerebrospinal fluid contamination with the cyst contents during resection. The link to the video can be found at: https://youtu.be/SskETPe5PXQ .

Cadaveric and ultrasonographic validation of needling placement in the obliquus capitis inferior muscle

BackgroundEvidence suggests that suboccipital musculature plays an important role in headache. Proper therapeutic approaches targeting this muscle are needed. ObjectiveOur aim was to determine with fresh cadavers and ultrasound imaging if a solid needle is able to properly penetrate the obliquus capitis inferior muscle during the application of dry needling. DesignA cadaveric and human descriptive study. MethodsNeedling insertion and ultrasound imaging of the obliquus capitis inferior muscle was conducted on 10 pain-free healthy subjects and 5 fresh cadavers. Needling insertion was performed using a 40 mm needle inserted midway between the spinous process of C2 and transverse process of C1. The needle was advanced from a posterior to anterior direction into the obliquus capitis inferior muscle with an inferior-lateral angle to reach the lamina of C2. For the cadaveric study, the obliquus capitis inferior placement was verified by resecting the superficial upper trapezius, splenius capitis, and semispinalis capitis muscles. For ultrasographic study, a linear transducer was aligned with the long axis of the obliquus capitis inferior muscle after needle insertion. ResultsBoth the cadaveric and ultrasonic studies showed that the needle penetrated the obliquus capitis inferior muscle during its insertion and that the tip of the needle rested against C2 laminae, thereby reaching the targeted muscle. ConclusionThis anatomical and ultrasound imaging study supports the assertion that needling insertion of the obliquus capitis inferior muscle can be properly conducted by an experienced clinician.

A Novel Approach for Imaging of Thoracic Outlet Syndrome Using Contrast-Enhanced Magnetic Resonance Angiography (CE-MRA), Short Inversion Time Inversion Recovery Sampling Perfection with Application-Optimized Contrasts Using Different Flip Angle Evolutions (T2-STIR-SPACE), and Volumetric Interpolated Breath-Hold Examination (VIBE).

BackgroundThe aim of this study was to introduce a novel method combining contrast-enhanced magnetic resonance angiography (CE-MRA), short inversion time inversion recovery sampling perfection with application-optimized contrasts using different flip angle evolutions (T2-STIR-SPACE) and volumetric interpolated breath-hold examination (VIBE) sequences in the assessment of thoracic outlet syndrome (TOS).Material/MethodsCE-MRA, T2-STIR-SPACE, and VIBE techniques were employed to evaluate neurovascular bundles in 27 patients clinically suspected of TOS. Images were evaluated to determine the cause of neurovascular bundle compression. Surgical exploration was performed in patients with abnormal magnetic resonance imaging (MRI) results.ResultsTwenty patients were found to be abnormal: 6 cases showed only neurogenic TOS and the correlates included infraclavicular hemangiomas (n=1) and transverse cervical artery (n=5). Arterial-neurogenic TOS was found in 4 cases, including subclavian lymph node metastasis from breast cancer (n=3) and schwannoma (n=1). Arterial-venous-neurogenic TOS was found in 1 subject, and the correlates included a fibrous band from the cervical rib and elongated C7 transverse process. In this case, the subclavian artery/vein was compressed dynamically. Venous–neurogenic TOS was noted in one subject. Nine patients were considered as post-traumatic TOS, including brachial plexus edema (n=3), the brachial plexus rupture (n=2), peri-brachial plexus effusion (n=3), and stenosis of the SCA (n=1). In the remaining 7 patients, MRI did not detect abnormalities.ConclusionsTOS can be evaluated by CE-MRA, T2-STIR-SPACE, and VIBE during a single examination, with a reduced contrast material dose. This imaging modality performs well in showing the anatomical structure of the neurovascular bundle and the cause of the compression.

Anatomical study of the ventral neurovascular structures and hypoglossal canal for the surgery of the upper cervical spine

The aim of this study is to evaluate the anatomical relationship between the bony structures and ventral neurovascular structures around craniovertebral junction (CVJ).Eleven fresh-frozen cadaveric specimens were dissected around CVJ. The anatomical relationships were evaluated between C1 bony structures (midline, lateral margin of the C1 lateral mass (LM) and C1 transverse process (TP)) and ventral neurovascular structure such as ICA and HN. Morphometric evaluation of occipital condyle was also performed.The diameter of the HN and the ICA was 2.4 ± 0.5 mm and 5.1 ± 0.2 mm. The ICA was located lateral to the C1 LM in 44.4% (ICA Group 1) and in front of lateral half of the C1 LM in 55.6% (ICA Group 2). The HN was located lateral to the C1 LM in 85% (HN Group 1) and in front of lateral half of the C1 LM in 15% (HN Group 2). HN Group 2 was significantly more common in ICA Group 2 (p < 0.05, OR = 2.00, 95% CI: 1.07–3.71). There was significant correlation between ICA and HN in terms of the distance from the midline, C1 LM and TP (r = 0.67, 0.87 and 0.76 respectively, P < 0.01).In conclusion, the HN location is related with ICA location and the medially located ICA is a risk factor of the HN located ventral to the C1 LM. These results demonstrate the vulnerability of the neurovascular structures during CVJ surgery and suggest that preoperative 3D-CTA or enhanced CT scan can be useful in guiding surgical technique.

Hear Hooves, Think Zebras: A Case Report & Systematic Literature Review of Isolated Neck Node Metastases from Prostate Cancer

Most cancers that metastasize to the cervical lymph nodes are from the upper aerodigestive tract. We use a case report and systematic literature review to highlight a very rare example of atypical metastatic spread to the cervical lymph nodes from advanced prostate cancer without involvement of other lymph node groups. All possible clinical, imaging and pathological documents were collected from the patient’s chart. Those documents were subjected to an independent review and data abstraction. A literature search was performed using relevant key words and MESH headings. Additional papers were found using the ‘cited by’ and ‘related articles’ functions of the search engines, and the references section of relevant papers. In July 2012, a 56 year old man presented with PSA 8ng/ml, cT2a, Gleason 8 prostate adenocarcinoma. Metastatic workup was negative and he had a radical prostatectomy. He had extensive positive surgical margins, pT3b N0, Gleason 9, with post-operative PSA of 0.77 and underwent salvage radiotherapy to the prostate bed with 2 years of adjuvant androgen deprivation therapy (ADT). In July 2015, he developed widespread bony metastases and received 6 cycles of chemotherapy with ADT. He subsequently developed castrate-resistant disease. In December 2017, the patient reported a painful lump in his left neck. PSA was 0.22 ng/ml. Ultrasound-guided aspiration confirmed metastasis from prostate cancer. CT revealed a level 3 neck node, 3cm in diameter. Whole body imaging indicated no other lymph node or visceral metastases. The patient then received 3 of 5 cycles in a phase 1 trial of an oncolytic virus plus monoclonal antibodies, but was removed from the study when his neck node disease progressed. Imaging showed necrotic nodes at left neck levels 2, 3, 5A. There was an infiltrative soft tissue mass surrounding the left C1 transverse process and encasing the left vertebral artery just below the skull base. There was no right-sided neck involvement. In July 2018, IMRT was used to deliver 51Gy in 20 fractions to a geometrically complex CTV in the left neck. To date, the neck nodes have reduced, but have not resolved completely. He still has no other lymph node or visceral metastases, and continues on ADT with a latest PSA of 1. An exhaustive review of the literature resulted in the identification of 13 case reports of cervical lymph node metastases from advanced prostate cancer, spanning 17 years. Misdiagnosis and delays to appropriate treatment were common due to the rarity of the phenomenon. 11 of 13 document nodes only in the left neck, and 5 of 13 report no lymphadenopathy except in the neck. All but one case were successfully palliated using ADT + chemotherapy. The remaining case saw disease progression on ADT, and received 70Gy chemo-rads to the left neck. This case report and literature review indicate that, although exceedingly rare, it is possible for advanced prostate cancer to metastasize to the left cervical lymph nodes without involvement of other lymph node groups. Improper assumptions about the site of primary disease, leading to inappropriate treatment choices, has been reported in the literature. ADT, chemotherapy and state-of-the-art radiotherapy can all be considered for palliation, on a case-by-case basis.

Rectus Capitis Lateralis Muscle: A Cadaveric Study of a Key Surgical Landmark in the Posterior and Lateral Approaches to the Jugular Foramen

The rectus capitis lateralis (RCL) is a small cervical muscle that arises from the transverse process of C1 and is intimately related to the jugular process and jugular foramen. We describe its morphology, neurovascular relationships, and its utility as one of the key surgical landmarks in approaches to the jugular foramen. Eight cadaveric heads were used to perform far-lateral and transmastoid approaches to the jugular foramen. The neurovascular relationships of the RCL were studied. The RCL originates from the transverse process of C1 and inserts onto the jugular process. It can be found in the muscular interval between the posterior belly of the digastric muscle and the superior oblique muscle with the occipital artery coursing between it and the posterior belly of the digastric muscle. It lies directly posterior to the internal jugular vein and cranial nerves (CNs) IX-XI as they exit the jugular foramen. The vertebral artery courses medially to the RCL as it exits foramen transversarium of C1. As the facial nerve exits the stylomastoid foramen, it is anterolateral to the RCL before turning to enter the parotid gland. The CN XII is seen between the RCL and the occipital condyle from a posterior view. The RCL usually is preserved unless jugular process needs to be removed to expose the jugular foramen. The RCL is an important surgical landmark for the early identification of the vertebral artery, internal jugular vein, facial nerve, and CNs IX-XII in approaches to the jugular foramen.

New Technique for Cryoneuroablation of the Proximal Greater Occipital Nerve.

Description of a new technique. To describe a safe ultrasound (US)-guided cryoneuroablation technique of the proximal greater occipital nerve (GON). Cryoneuroablation is a treatment option for occipital neuralgia, providing more sustained relief when steroid injections fail. US can identify the proximal GON between the C2 spinous and C1 transverse process over the inferior oblique capitis muscle (IOCM), where the GON is clearly visualized. US-guided GON injections are often performed with an out-of-plane approach; however, that approach is difficult with cryoneuroablation, because the probe has no opening (prohibiting hydrodissection), and the size and dullness of the probe hinders easy manipulation. University-based outpatient pain clinic. We provide a description of the procedure based on experience in the authors' clinic. With the patient in the prone position, the US probe is placed parallel to the IOCM. The GON is seen on top of the IOCM; a midline 2-mm incision allows access to the bilateral GONs with a single skin entry. Using an in-plane approach, the cryo probe is advanced to the nerve in a medial-to-lateral direction, with constant US visualization, staying far away from the spinal cord and vertebral artery, which increases safety. Based on anecdotal evidence from the authors' clinic, cryoneuroablation of the proximal GON can be performed safely at the level of the IOCM. The procedure described is based on anecdotal evidence from a small number of patients; however, the procedure is promising and formal study is warranted.

Do not follow the bone, follow the nerve ultrasound-guided stellate ganglion block: a reconfirmation.

Indirect and direct methods have been used to localize the stellate ganglion. Identifying the C6 and C7 transverse process can be a technical challenge for practitioners when performing an ultrasound-guided stellate ganglion block. Following the nerve roots from the interscalene plexus into the corresponding foramen can serve as a reconfirmation for identifying the C6 and C7 transverse process.

The effect of ultrasound guided superior cervical sympathetic ganglion block to abducens nerve palsy caused by microvascular ischemia-a case report

The abducens nerve palsy is most likely caused by microvascular issue. Spontaneous recovery of vasculopathic abducens nerve palsies was common at 3 to 6 months. But recovery time was longer when many risk factors were present. Several patients had residual esotropia or abduction deficit. Cervical sympathetic block has an established use in treating patients with disorders related to cranial circulatory insufficiency. It causes a significant increase in cerebral blood flow 1,2. We report a case of a 67-year-old man with acute horizontal diplopia and right periocular pain. He had been diagnosed with right abducens nerve palsy caused by microvascular ischemia. We performed ultrasound-guided superior cervical sympathetic ganglion blocks. The patient was placed in a supine position, and his head was turned approximately 45 degrees to the left side. A transducer was transversely oriented over the right side of his neck, and the transverse process of C6 was located to the cricoid cartilage level. The transducer was moved in the cephalad direction along the neck to locate the common carotid bifurcation. After identifying the oval-shaped and hypoechoic structure between the longus capitis muscle and the starting point to branch off the common carotid bifurcation, a 23-gauge needle was introduced slowly from a lateral approach with the in-plane technique using ultrasound guidance. The needle was inserted until it approached the target site, and it was positioned immediately adjacent to the structure appearing to be the SCSG. We performed the SCSG block with 5 cc of 0.2 % ropivacaine, and then we identified Horner's sign on the same side after the injection. He received blocks in the same manner once every three or four days due. After four weeks, the symptoms had been completely resolved. We introduce ultrasound-guided superior cervical sympathetic ganglion blocks for management of abducens nerve palsy caused by microvascular ischemia, which could be an effective novel method to promote recovery from diplopia. We think that the recovery of ischemic demyelination of a portion of the nerve is greatly assisted by an improvement in the cerebral blood flow.

Functional Results of Cervical Rib Resection for Thoracic Outlet Syndrome: Impact on Professional Activity

The aim of this study is to report long-term functional results following cervical rib (CR) resection for thoracic outlet syndrome (TOS). This monocentric study included all cases of resection of CR for TOS performed between January 2004 and December 2016. Data were retrospectively collected from the hospital electronic database including preoperative symptoms and the evaluation of occupational well-being, intraoperative data, and early clinical evaluation and occupational well-being during the postoperative period. Patients were categorized as neurogenic TOS (NTOS), arterial TOS (ATOS), arterial and neurogenic TOS (ANTOS), venous TOS (VTOS), or asymptomatic according to preoperative evaluation. We evaluated the improvement in work life between the preoperative and the postoperative period. Further assessment was a negative Roos or elevated arm stress test (EAST) during the postoperative period. Thirty-three patients with a median age of 38.5years (30-46) were included. Thirty-six procedures were performed: 33% to treat ATOS (12/36), 39% for NTOS (14/36), 19% for ANTOS (7/36), 3% for VTOS (1/36), and 6% (2/36) for asymptomatic lesions. There were 9 cases of subclavian artery aneurysms leading to additional arterial repair. Due to distal embolization, a cervical sympathectomy was associated in 5 procedures. First rib resection was associated in 4 procedures (11%) and C7 transverse process resection was performed in 15 procedures (42%). The technical success rate was 100% and intraoperative complications were observed in 4 patients (11%) with favorable postoperative outcomes. During the early postoperative period, 3 Claude Bernard-Horner's syndrome and 1 asymptomatic subclavian dissection were detected. Late complications included 2 bypass thromboses (6%) at 6weeks and 16months. Postoperative EAST improved in 16 limbs (44%). Prior to the procedure, only 27% (9/33) patients had normal work lives. After the procedure, 64% (21/33) of patients were able to return to their normal work activity. CR resection for TOS seems to be a safe procedure leading to good short- and long-term clinical results with a favorable impact on recovering a normal work life in these young patients.

Surgical outcomes of neurogenic thoracic outlet syndrome based on electrodiagnostic tests and QuickDASH scores

In total, 665 of 680 (97%) patients with neurogenic thoracic outlet syndrome (NTOS) improved with conservative treatment. The remaining (3%) patients (15 of 680 patients) did not benefit after 3 months of conservative treatment and were referred for transaxillary first rib resection. We retrospectively compared the preoperative and postoperative (3 months) electromyelography and Quick Disability of Arm, Shoulder and Hands results of operated NTOS patients. Three of the 15 (20%) patients in the surgical cohort were male, with a median age of 25.3 ± 4.16 years, and the other 12 patients (80%) were female with a median age of 31.9 ± 9.48 years. Two of the 15 patients had a cervical rib, 4 of the 15 patients had an extension of the C7 transverse process, and 14 of the 15 patients had a cervical band. These bone and tissue abnormalities were removed in addition to the first rib resection and division of the subclavius muscle and the anterior scalenus and middle scalenus muscles. QuickDASH scores were 1062 preoperatively and 549 postoperatively. The latency of the median F-wave was significantly prolonged on the affected side compared to the unaffected side preoperatively (p = 0.015). There was no remarkable difference in the latency of ulnar F-waves between sides (p = 0.246). The medial antebrachial cutaneous nerve response values increased significantly postoperatively (p < 0.0001). Significant increases in ulnar sensory nerve action potential values amplitude ratio (p < 0.003) and median nerve motor amplitudes (p < 0.0001) were also found postoperatively.

Muscular-stage Dissection during Far Lateral Approach and Its Transcondylar Extension.

Background The far lateral approach includes exposure of the C1 transverse process, vertebral artery, posterior arch of the atlas, and occipital condyle. We designed a method for systematic muscular-stage dissection and present our experience with this approach. Operative Methods We used a horseshoe scalp flap that was reflected downward and medially. The lateral muscle layers were separated layer to layer to expose the suboccipital triangle. The medial muscle layers were separated in the midline and reflected in a single layer. At this stage, the midline of the C1 process and the foramen magnum were identified. The rectus capitis posterior major muscle was reflected to expose the posterior arch of the atlas. The C1 transverse process and vertebral artery were identified by reflection of the superior oblique muscle. The occipital condyle was separated accordingly. Results We used this method of muscular dissection in 10 patients (foramen magnum meningioma, n = 5; hypoglossal schwannoma, n = 2; others, n = 3). Systematic muscular-stage dissection facilitates identification of the anatomical landmarks with no vertebral artery injury. Gross total removal was obtained in all 9 patients with complex tumors. The patient with vertebral artery dissection successfully underwent proximal clipping. Conclusion Our muscular-stage dissection could contribute to safe and effective surgery for the far lateral approach.

Reference Values for the Scalene Interval Width During Varying Degrees of Glenohumeral Abduction Using Ultrasonography

ObjectiveThe aim of this study was to establish reference values for the width of the interval between the anterior and middle scalene muscles using ultrasonography during varying degrees of glenohumeral joint (GH) abduction. Reliability and body mass index (BMI) data were also assessed. MethodsInterscalene triangles of asymptomatic participants were scanned bilaterally in the transverse plane. Images were obtained at 0°, 90°, and 150° of GH abduction with the participant seated. Width measurements were taken between the anterior and middle scalene muscle borders by bisecting the C6 nerve root as it passed superficial to the posterior tubercle of the C7 transverse process. Intra- and interexaminer reliability and BMI correlation were studied. Statistical significance was defined as P ≤ .05. ResultsImages of 42 scalene intervals were included from 21 participants (11 female). Mean participant age was 25.3 ± 3.9 years; mean BMI was 25.4 ± 2.7 kg/m2. Scalene interval measurements at 0°, 90°, and 150° of GH abduction were 4.5 ± 0.5 mm, 4.6 ± 0.5 mm, and 4.4 ± 0.7 mm, respectively, without a significant difference (P = .07). Intraexaminer reliability was excellent (0°: intraclass correlation coefficient [ICC] = 0.82; 90°: ICC = 0.89; 150°: ICC = 0.90). Interexaminer reliability was good to excellent (0°: ICC = 0.59; 90°: ICC = 0.85; 150°: ICC = 0.89). Body mass index was positively correlated only at 0° of GH abduction. ConclusionsThis study establishes previously unreported reference ultrasonography values for the width of the scalene interval. Intraexaminer reliability was excellent at all glenohumeral positions, and interexaminer reliability was determined to be good to excellent. Body mass index was positively correlated only at 0° of GH abduction.

Neurological Signs and Symptoms of True Neurogenic Thoracic Outlet Syndrome

Thoracic outlet syndrome (TOS) is a well-known disorder, but many aspects of its pathology, including its definition, has been disputed. True neurogenic TOS (TN-TOS) is a rare but well-defined clinical condition. TN-TOS results from the compression of the C8/T1 roots (dominant for the T1 root) or the proximal lower trunk of the brachial plexus by a fibrous band. The band extends from the first rib to either the tip of an elongated C7 transverse process or a rudimentary cervical rib. The most common presenting symptoms of TN-TOS are insidious-onset atrophy and weakness of the intrinsic hand muscles, predominantly in the thenar eminence and radial digit flexors. Nerve conduction studies demonstrate pathognomonic findings: severely attenuated compound muscle action potential of the abductor pollicis brevis muscle, and usually, loss of the sensory nerve action potential of the medial antebrachial cutaneous nerve. Numbness and sensory loss are typically observed, mainly in the medial forearm, although they are usually mild, and may be absent in some patients. Severe pain or paresthesia proximal to the elbow is not observed. The classical concept of TOS underlie nonspecific neurogenic TOS. It has been primarily diagnosed using provocative maneuvers. However, there is controversy regarding its pathological conceptualization and existence, as objective evidence of the disease is still lacking.

Sonoanatomical Change of Phrenic Nerve According to Posture During Ultrasound-Guided Stellate Ganglion Block.

ObjectiveTo evaluate the risk of phrenic nerve injury during ultrasound-guided stellate ganglion block (US-SGB) according to sonoanatomy of the phrenic nerve, and determine a safer posture for needle insertion by assessing its relationship with surrounding structure according to positional change.MethodsTwenty-nine healthy volunteers were recruited and underwent ultrasound in two postures, i.e., supine position with the neck extension and head rotation, and lateral decubitus position. The transducer was placed at the anterior tubercle of the C6 level to identify phrenic nerve. The cross-sectional area (CSA), depth from skin, distance between phrenic nerve and anterior tubercle of C6 transverse process, and the angle formed by anterior tubercle, posterior tubercle and phrenic nerve were measured.ResultsThe phrenic nerve was clearly identified in the intermuscular fascia layer between the anterior scalene and sternocleidomastoid muscles. The distance between the phrenic nerve and anterior tubercle was 10.33±3.20 mm with the supine position and 9.20±3.31 mm with the lateral decubitus position, respectively. The mean CSA and skin depth of phrenic nerve were not statistically different between the two positions. The angle with the supine position was 48.37°±27.43°, and 58.89°±30.02° with the lateral decubitus position. The difference of angle between the two positions was statistically significant.ConclusionUltrasound is a useful tool for assessing the phrenic nerve and its anatomical relation with other cervical structures. In addition, lateral decubitus position seems to be safer by providing wider angle for needle insertion than the supine position in US-SGB.

Styloid/C1 transverse process juxtaposition as a cause of Eagle's syndrome.

The purpose of this case report was to characterize styloid/C1 transverse process juxtaposition as a cause for Eagle's syndrome. A case series was conducted with a chart review of 5 patients with radiographic evidence of jugular vein compression who underwent styloid process excision between 2010 and 2013. There were 4 men and 1 woman, aged 35 to 62 years (mean, 46 years). Cervicalgia (4 of 5 patients) and otalgia (4 of 5 patients) were the most commonly reported symptoms. Styloid process length ranged from 2.4 to 8.5 cm. The distance between the styloid process and the transverse process of C1 ranged from 0.05 to 0.46 cm. All patients underwent a transcervical approach for the excision of the styloid process with immediate postoperative resolution of symptoms and good cosmetic results. Styloid/C1 transverse process juxtaposition can produce symptoms of cervicalgia and otalgia even in the setting of a normal length styloid process. The transcervical approach is safe and effective for excision of the styloid process and has good functional and cosmetic results.

Morphometric Study of the Hypoglossal Nerve and the Hypoglossal Canal for the Surgery of the Upper Cervical Spine

Objective The upper cervical pathology is not an uncommon disease in the congenital anomaly, elderly population, and patients with rheumatoid. Newly developed operative techniques in high cervical region could be related to neurovascular injury. The objective of this study was to determine the anatomic relationship of the hypoglossal nerve (HN), internal carotid artery (ICA), bony structures, and hypoglossal canal and demonstrate the vulnerability of the neurovascular structures. Methods Eleven fresh cadavers (5 male and 6 female) were dissected bilaterally to expose neurovascular structures of the high anterior cervical region and hypoglossal canal. The anatomical relationship was evaluated between C1 bony structures (midline, lateral mass, and C1 transverse process) and the ICA and HN. The angle of the hypoglossal canal was also evaluated. Results The HN consistently traveled toward the midline at C2–3 and was safe caudal to C3–4. The HN is usually located lateral to the ICA. Relative anatomical relationship between the HN and surrounding bony structures at the level of C1 are as given below. The mean diameter of the HN was 2.4 mm (2–3.5 mm). The mean distance between the midline and the HN was 30.15 mm (24–35 mm). The mean distance between the margin of the C1 lateral mass (LM) and the HN was 4 mm (−3–11 mm). The mean distance between the C1 transverse process and the HN was 9.3 mm (3–16 mm). The transverse angle of the hypoglossal canal was between 31.6 and 55.5 degrees. The mean distance between the midline and the ICA was 26.06 mm (18–32 mm). In the cases of the medially displaced ICA, the HN is located more on the medial side relative to the LM. There was no reversed anatomical location of the HN and the ICA in the studied specimen. Conclusion On the basis of this study, spine surgeons can have enhanced knowledge of upper cervical anatomy. Although it has been rarely reported in the literature, the hypoglossal nerve and the ICA may be damaged during upper cervical spine surgery, especially in the cases with the ICA displaced medially.