Sectioning of C2 nerve roots during C1–2 fusion: report of aberrant vertebral artery during C2 nerve root sectioning. Illustrative case

BACKGROUND Sectioning the C2 nerve root is increasingly utilized during posterior C1–2 fusion, as the nerve overlies the entry point for C1 lateral mass screws and the C1–2 joint. Nerve sectioning improves visualization for screw placement and enables joint decortication for arthrodesis. While rare, vascular injury is a devastating complication of atlantoaxial fusion. Anomalous vascular anatomy at C1–2 greatly increases risk of iatrogenic injury. OBSERVATIONS A 78-year-old female with rheumatoid arthritis and prior C2–7 fusion presented with myelopathy from a compressive pannus at C1–2. She underwent C1 laminectomy and C1–2 posterior instrumented fusion. Intraoperatively, arterial bleeding occurred as the right C2 nerve root was sectioned. Vertebral artery injury was suspected, and tamponade was performed while vascular control was established. The artery passed aberrantly beneath the nerve root in the C1–2 foramen. It was repaired microsurgically, and patency was confirmed using indocyanine green. The remainder of the fusion was aborted. The patient wore a cervical collar and was treated with aspirin for 6 weeks before undergoing instrumented fusion. The patient suffered no deficits. LESSONS Although rare, anomalous vertebral artery anatomy increases risk of injury at time of C2 nerve root sectioning. Preoperative assessment of the vasculature is vital.

Supplementation of Screw-Rod C1-C2 Fixation With Posterior Arch Femoral Head Allograft Strut

BACKGROUND Numerous C1-C2 fixation techniques exist for the treatment of atlantoaxial instability. Limitations of screw-rod and sublaminar wiring techniques include C2 nerve root sacrifice and dural injury, respectively. We present a novel technique that utilizes a femoral head allograft cut with a keyhole that rests posteriorly on the arches of C1 and C2 and straddles the C2 spinous process, secured by sutures. OBJECTIVE To offer increased fusion across C1-C2 without the passage of sublaminar wiring or interarticular arthrodesis. METHODS A total of 6 patients with atlantoaxial instability underwent C1-C2 fixation using our method from 2015 to 2016. After placement of a C1-C2 screw/rod construct, a cadaveric frozen femoral head allograft was cut into a half-dome with a keyhole and placed over the already decorticated dorsal C1 arch and C2 spinous process. Notches were created in the graft and sutures were placed in the notches and around the rods to secure it firmly in place. RESULTS The femoral head's shape allowed for creation of a graft that provides excellent surface area for fusion across C1-C2. There were no intraoperative complications, including dural tears. Postoperatively, no patients had sensorimotor deficits, pain, or occipital neuralgia. 5 patients demonstrated clinical resolution of symptoms by 3 mo and radiographic (computed tomography) evidence of fusion at 1 yr. One patient had good follow-up at 1 mo but died due to complications of Alzheimer disease. CONCLUSION The posterior arch femoral head allograft strut technique with securing sutures is a viable option for supplementing screw-rod fixation in the treatment of complex atlantoaxial instability.

Bow Hunter's Syndrome: Complete Microsurgical Decompression of Vertebral Artery by Far Lateral Retrocondylar Approach: 3-Dimensional Operative Video

This 50-yr-old man had a 15-yr history of presyncopal episodes that were precipitated by turning his head to the right, and had worsened recently. Cerebral angiogram demonstrated complete cessation of anterograde flow in left vertebral artery (VA) at the level of the C1 sulcus arteriosus while turning head to right, indicating dynamic compression at the C1 level. Patient underwent left extreme lateral retrocondylar approach, partial C1 laminectomy and opening of the C1 foramen with complete microsurgical decompression of the VA. After skin incision, meticulous muscle dissection was performed and superior and inferior oblique muscles were disconnected from the tubercle of C1. The VA was exposed, and three areas of constriction were visible, first at the atlanto-occipital membrane laterally; second, located more medially as the artery curved around the occipital condyle to enter the posterior fossa; and third, located anterior to C2 nerve root. The artery was dissected from all the surrounding tissues, preserving the C2 nerve root, and the Cl foramen was opened completely. The Cl lamina was also partially resected and grooved to allow free placement of the VA. The VA was also decompressed near the C2 foramen. Postoperative computed tomography angiogram of the head and neck showed complete decompression of VA. The patient had no episodes of presyncope or dizziness while turning head to right and his mRs was 0 at 8 mo follow up. This 3D video shows the technical nuances of decompression of V3 segment of VA in bow hunters's syndrome. Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Rare cervical nerve root C2-C3 schwannoma

<p class="abstract"><span lang="EN-IN">10% of schwannomas that occur in the head and neck region mostly originate from the vagus or sympathetic nervous system whereas those arising from C2 nerve root are extremely rare. Extracranial schwannomas in the head and neck region are rare neoplasms. Diagnosis is established by imaging studies such as magnetic resonance imaging or computed tomography, while FNAC is used to rule out other condition. Histopathology gives definitive diagnosis. The accepted treatment for these tumors is surgical resection with preservation of the neural pathway. We present a rare case of cervical nerve (C2-C3) root schwannoma of 50 year old male who presented with right lateral neck swelling with pain radiating to right shoulder associated with right shoulder stiffness</span>. The swelling which also had an intervertebral part <span lang="EN-IN">was removed successfully through a posterior neck incision with no post-operative neurological symptoms.</span></p>

Atlantoaxial Fusion Using C1 Sublaminar Cables and C2 Translaminar Screws

BACKGROUND Atlantoaxial instability, which can arise in the setting of trauma, degenerative diseases, and neoplasm, is often managed surgically with C1–C2 arthrodesis. Classical C1–C2 fusion techniques require placement of instrumentation in close proximity to the vertebral artery and C2 nerve root. OBJECTIVE To report a novel C1–C2 fusion technique that utilizes C2 translaminar screws and C1 sublaminar cables to decrease the risk of injury to the vertebral artery and C2 nerve root. METHODS To facilitate fixation to the atlas, while minimizing the risk of injury to the vertebral artery and to the C2 nerve root, we sought to determine the feasibility of using a soft cable around the C1 arch and affixing it to a rod connected to C2 laminar screws. We reviewed our experience in 3 patients. RESULTS We used this technique in patients in whom we anticipated difficult C1 screw placement. Three patients were identified through a review of the senior author's cases. Atlantoaxial instability was associated with trauma in 2 patients and chronic degenerative changes in 1 patient. Common symptoms on presentation included pain and limited range of motion. All patients underwent C1–C2 fusion with C2 translaminar screws with sublaminar cable harnessing of the posterior arch of C1. There were no reports of postoperative complications or hardware failure. CONCLUSION We demonstrate a novel, technically straightforward approach for C1–C2 fusion that minimizes risk to the vertebral artery and to the C2 nerve root, while still allowing for semirigid fixation in instances of both traumatic and chronic degenerative atlantoaxial instability.

Malignant Peripheral Nerve Sheath Tumor of the C2 Nerve Root: Case Report

Here we present the case of a 36-year-old man who was found to have a symptomatic malignant neural sheath tumor growing from the C2 nerve root following a period of progressively worsening headaches. The patient was successfully treated with surgical resection resulting in resolution of cranial nerve deficits. Though uncommon, malignant peripheral nerve sheath tumor must be considered in the differential diagnosis of tumors involving the cervical nerve roots and carotid space.