Vertebral artery loop--a cause of cervical radiculopathy

Anterior artery release, distraction and fusion (ARDF) for radiculopathy caused by a vertebral artery loop

BACKGROUND

Anomalous vertebral artery (VA) with loop formation is a rare cause of cervical nerve root compression. Various techniques with anterior and posterior approaches have been described for surgical treatment once conservative treatments fail. We herein present a case treated with the new technique of anterior release, distraction and fusion (ARDF) and further provide an updated review of surgically managed VA loops in the subaxial spine.

CASE DESCRIPTION

A 76-year-old female complained of a 6-year history of pulsating, shooting pain in her right arm to the thumb. After obtaining repeated MRI, the VA loop compressing the right-sided C6-nerve root was detected. A neurovascular decompression through ARDF which led to an indirect loop straightening was performed. The patient immediately improved after surgery and remained pain-free 1 year postoperative.

CONCLUSION

Neural irritation due to VA loop formation is a rare cause of cervical radiculopathy. While various surgical strategies have been described, we believe that anterior and anterolateral approaches are the safest to yield neurovascular decompression. We described and documented ARDF (anterior VA release, intervertebral distraction and fusion) on a patient case.

LEVEL OF EVIDENCE

II (Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding).

Cervical radiculopathy caused by vertebral artery loop formation: a case report

Vertebral artery loop formation is a rare cause of cervical radiculopathy. We report a case of a 70-year-old man who was referred because of a chronic cervicobrachialgia. Initial plain cervical x-ray showed widening of the left C3-C4 intervertebral foramen. Additional magnetic resonance angiography revealed the presence of a vertebral artery loop, which had migrated into the left C3-C4 neural foramen and caused compression of the left C4 nerve root. Surgery was considered, but the patient’s symptoms resolved with conservative treatment. The aim of this case report is to raise the knowledge of both clinicians and radiologists about vertebral artery loop formation as a rare but potentially life-threatening cause of cervical radiculopathy. If overlooked, cerebrovascular stroke during transforaminal cervical steroid injections or catastrophic vertebral artery damage during surgery may occur.

An anatomical investigation of the proximal vertebral arteries (V1, V2) in a select South African population

Introduction

The most common type of vascular complication during cervical spine surgery is the vertebral artery (VA) injury. The presence of anatomical variation in the artery's morphology has been a significant factor for arterial injury during surgery. Therefore, physicians planning interventions in the craniospinal region need to be aware of the extents of variations. In addition to vascular injury, anatomical variations can predispose to some pathologies in the posterior circulation territory. To provide useful data to interventional radiologists, anatomists, and surgeons, we evaluated the anatomical features of the V1 and V2 segments of the VA in a South African population.

Materials and methods

The study is an observational, retrospective chart review of 554 consecutive South African patients (Black, Indian and White) who had undergone computed tomography angiography (CTA) from January 2009 to September 2019.

Results

The VA exhibited morphological variation in its course. We report the incidence of variant origin of the left VA, all from the aortic arch. Variation in the level of entry into the transverse foramen ranged between C7 and C3. A left dominant pattern was observed; we also report on hypoplasia of the VA. In addition, we report incidence of VA tortuosity at V1, V2 to be 76.6% and 32.1%, respectively.

Conclusions

The baseline data established in this study regarding the diameter, variant origin, and level of entry into the transverse foramen will assist neurosurgeons and interventional radiologists in interpreting, diagnosing, and planning and executing various vascular procedures and treatment of pathology in the vicinity of the VA.

Morphometric Study of the Cervical Spinal Canal Content and the Vertebral Artery

BACKGROUND

The morphological features of the cervical spinal nerves (C1-C8), their dimensions, and their anatomical relations with the vertebral artery are important for safe spinal surgery. The aim of the present study is to give detailed morphological data of the region to avoid complications.

METHODS

Five formalin-fixed adult cadavers were studied. The cervical spinal nerves and the vertebral artery were exposed via the posterior approach, and detailed anatomy and morphometric measurements were evaluated. The following measurements were documented: angles between the spinal nerve and the spinal cord of C1 to C8, width of the C1 to C8 spinal nerves at their origin, distance of the spinal cord to the vertebral artery, number of dorsal rootlets, length of the dorsal root entry zone of C1 to C8, and distance between respective spinal nerves. Further, the average length and width of the transverse foramen were measured.

RESULTS

The average angle between the spinal cord and the spinal nerve within the vertebral canal ranged between 54 and 87 degrees and were most acute at C5 (54 degrees) compared to the rest of the cervical spinal nerves. The average width of the spinal nerves (mean ± SD), was thickest at C5 (5.7 ± 1.2 mm) and C6 (5.8 ± 0.7 mm). The average largest distance between the vertebral artery and the spinal cord was at C2 (14.3 ± 1.7 mm) and the smallest at C5 (7.3 ± 0.9 mm) and C6 (7.3 ± 2.2 mm) spinal levels. The number of dorsal rootlets was most numerous at C6 (8.25 ± 0.6) and C7 (7.25 ± 0.9). The dorsal root entry zone length was the largest at C5 (13.0 ± 1.6 mm) and C6 (13.75 ± 0.5 mm). The distance between respective spinal nerves was largest between C2 and C3 (11.8 ± 2.2) and C7 and C8 (11.5 ± 0.6).

CONCLUSION

The knowledge of detailed anatomy of the cervical spine (C1-C8) and its relations with the vertebral artery will reduce the unwanted damage to the vital structures of the region.

Surgical Interventions for Cervical Radiculopathy Caused by a Vertebral Artery Loop: A Case Report and Review of the Literature

BACKGROUND

Aberrant vertebral artery loops are a rare clinical condition, with sparse data regarding the optimal treatment guidelines for individual patients. The heterogeneity of treatment options in the literature creates a problem when tailoring treatments to individual patients. In this review of the literature, multiple surgical treatments for cervical vertebral artery loops were analyzed and compared. In addition, this article provides a clinical case of a patient with a vertebral artery loop.

METHODS

A literature review was conducted to identify studies investigating surgical treatments for a vertebral artery loop. Different surgical techniques were examined and the involved techniques and approaches described. The outcomes were assessed for each study and the effectiveness of the treatment determined.

RESULTS

Twelve articles met the inclusion criteria for this review. Six types of surgical interventions were found in the literature. Each intervention had similar postoperative results, leading to either a significant improvement or a complete resolution of symptoms.

CONCLUSIONS

Multiple successful surgical interventions have been described in the medical literature. However, because of the lack of evidence-based studies, no surgical intervention protocol could be determined. Treatment should therefore be tailored to individual patients' characteristics. Because not every radiologically detected vertebral artery loop is the main reason for a patient's symptoms, a thorough multidisciplinary approach is justified and advocated in patients with an atypical presentation, before a neurosurgical intervention takes place. More deliberate clinical decisions can be made once the understanding of the pathogenesis of this rare disease entity has been established and treatment protocols formulated.

Vertebral Artery Sacrifice: Novel Strategy in Treatment of Vertebral Artery Loop

BACKGROUND

We report a case of cervical radiculopathy caused by an anomalous vertebral artery (VA) and the efficacy of endovascular vertebral artery sacrifice.

CASE DESCRIPTION

A 62-year-old woman was referred to neurosurgery because of an 8- to 9-year history of progressive left C6-7 radiculopathy refractory to other forms of treatment. Radiologic evaluation showed an abnormally tortuous loop of VA at V2 causing direct neurovascular compression at the C6-7 level. Initial attempts at microvascular decompression with posterior foraminotomy were unsuccessful due to strong adhesion between the VA and C7 nerve root. This was followed by an endovascular VA sacrifice relieving the patient's symptoms.

CONCLUSIONS

Cervical root compression by an aberrant or anomalous extracranial VA is a rare cause of radiculopathy. Endovascular VA sacrifice provided symptom relief in our patient, when other options failed. To our knowledge, this is the first report of endovascular VA sacrifice for management of cervical radiculopathy due to VA loop.

Anterolateral Approach for a Cervical Nerve Root Compression Syndrome Due to an Ectatic Vertebral Artery

BACKGROUND AND IMPORTANCE

Nerve root compression by an ectatic vertebral artery is a known but easily overlooked cause of cervical radiculopathy. Management options include nonoperative conservative therapies or surgical approaches designed to relieve the compression via anterior or posterior cervical approaches.

CLINICAL PRESENTATION

A 72-yr-old female presented with a 6-mo history of sharp, shooting pain in her right arm and shoulder and deltoid weakness. Imaging demonstrated a vertebral artery loop compressing the proximal right C5 nerve root. She previously underwent both nonoperative measures as well as posterior foraminotomy at this level with limited improvement in her pain. Therefore, we performed an anterolateral approach for vascular decompression of the C5 nerve root from the vertebral artery loop. Patient has been pain-free at 1 yr with full recovery of her deltoid weakness.

CONCLUSION

Vertebral artery loop formation is an uncommon cause of cervical radiculopathy, which can be readily treated by vascular decompression of the nerve root-vertebral artery loop complex. Although anomalous vertebral artery compression of a cervical nerve root is rare, it is increasingly being recognized as a readily treatable entity that can lead to lasting and full neurological recovery. We also include an operative video to illustrate the vascular decompression of an ectatic vertebral artery causing severe cervical radiculopathy.

Compression Syndromes of the Vertebral Artery at the Craniocervical Junction

Compression syndromes of the vertebral artery that occur at the craniocervical junction are extremely rare causes of haemodynamic insufficiency of the posterior cerebral circulation. The aetiology of the compression syndrome may be a malformation, trauma, tumour, infection or degenerative pathology. This may lead to dynamic vertebral artery occlusion where the vessel courses around the atlas and the axis-the so-called V3 segment. This in turn may result in insufficient collateral flow to the posterior fossa. The clinical picture is a vertebrobasilar insufficiency syndrome of variable expression ranging from vertigo to posterior fossa stroke. The typical clinical presentation is syncope occurring during rotation of the head, also known as 'bow hunter's syndrome'. The workup is based on dynamic angiography and computed tomography angiography. The treatment of choice is surgical vascular decompression, resulting in a good clinical outcome. However, in some instances, atlantoaxial fusion may be indicated. Alternatively, conservative and endovascular options have to be considered in inoperable patients.

The diagnosis and management of a vertebral artery loop causing cervical radiculopathy

BACKGROUND

Cervical radiculopathies are rarely caused by vertebral artery loop formation, which is estimated to be present in less than 3% of patients. It is uncertain what causes the loop formation: some propose an association with spondylotic changes or trauma, whilst others suggest hypertension and atherosclerosis may be responsible. CASE REPORT 1: A 35-year-old male patient presented with signs and symptoms of cervical radiculopathy that was not improved with anterior cervical discectomy and fusion surgery performed 2 years beforehand. Vertebral artery loop was discovered at the level C5/6 on the MRI. Vertebral artery transposition surgery via a lateral approach was performed at the level of the left C5/6 for symptoms of left C6 radiculopathy. Deroofing of the transverse process was performed with post-surgical complete improvement in weakness and pain. CASE REPORT 2: A 48-year-old female patient presented with a 10-year history of left shoulder pain with occasional radiation into her middle three fingers accompanied by intermittent paraesthesia and weakness. Numerous shoulder surgeries, Botox injections and suprascapular nerve blocks had not provided any significant benefit. A vertebral artery loop was identified at the level of C3/4 and C4/5 on the left with cervical MRI. Transposition surgery of these two levels provided some post-surgical improvement in pain.

CONCLUSION

Vertebral artery loop formations are a rare but potential cause for cervical radiculopathy. In two cases, the loop formations were not radiographically reported on MRI, thus clinicians should be aware of this as a differential diagnosis in the management of cervical radiculopathy. The presented surgical approach may be useful in managing future cases of vertebral artery loop formation causing cervical radiculopathy resistant to conservative measures.

Anterior Transposition of Anomalous Tortuous Vertebral Artery Causing Cervical Radiculopathy: A Report of 2 Cases and Review of Literature

OBJECTIVE

Cervical radiculopathy secondary to compression from vertebral artery (VA) tortuosity is a rare entity. We describe successful transposition through an anterolateral approach of tortuous VA loops causing cervical radiculopathy.

METHODS

Two patients with cervical radiculopathy (first case at C5-6 and second case at C3-4) secondary to anomalous VA loop compression underwent anterolateral approaches to the cervical spine for decompression and VA transposition. The anterior transverse foramina were drilled to unroof the VA loop, which was dissected free from the exiting nerve root.

RESULTS

In both cases, the affected cervical nerve root was successfully decompressed with both radiographic and clinical improvements in radiculopathy symptoms. We found 8 other cases of VA transposition via either an anterolateral approach or a posterolateral approach described in the literature. Our second case of anterolateral VA transposition at the C3-4 level is the first case at this level and the highest level reported in the literature.

CONCLUSIONS

Decompression using an anterolateral approach with direct microvascular transposition of the VA is a safe and effective treatment of this pathology and addresses the cause of radiculopathy more directly than the posterolateral approach.

Vertebral artery loops in surgical perspective

PURPOSE

Vertebral artery loop is a congenital or acquired anomaly. Vertebral artery loops are incidentally diagnosed during evaluation of neck problems and trauma. We aimed to present the incidence of VA loops using magnetic resonance angiography in consecutive patients and discuss epidemiological data including the gender, age, location, signs and symptoms, treatment approaches and outcomes of VA loops via analyzing literature.

METHODS

In the first leg of our two-legged study, consecutive patients were evaluated using magnetic resonance angiography to detect any medial loop of vertebral arteries. The study period was from October 2015 to March 2016. In the second leg, academic databases about medial loop of vertebral artery were screened. Case reports, case series, abstracts and references of relevant literature were searched manually to avoid any missing cases.

RESULTS

We evaluated 239 consecutive patients using magnetic resonance angiography. Twenty-one patients were excluded from the study due to inadequate image acquisition, aplastic vertebral artery and/or concomitant vertebral artery stenosis. Medial loop of V2 vertebral artery was observed in 13 patients (5.9 %): 9 with left, 2 with right and 2 with bilateral medial V2 loop. Patients with medial V2 loop were significantly older than patients with straight vertebral arteries (70.30 vs. 62.36, p = 0.028). In the literature analysis, VA loops were more commonly observed at V2 segment (90.5 %). Vertebral artery loops were mostly diagnosed at the 5th and 6th decades of life predominantly in females. The most common signs and symptoms were radiculopathy and/or neck pain, and signs and symptoms of vertebrobasilar insufficiency.

CONCLUSIONS

Concise pre-operative evaluation of the vertebral arteries is essential to avoid the injury of undiagnosed VA loops during surgery, which might result in catastrophic circumstances. Further evaluation of the vertebral arteries using MR angiography is required, especially in elder age, before cervical spine surgeries.

Medial loop of v2 segment of vertebral artery causing compression of proximal cervical root

Objective

It is rare that the medial loop in the V2 segment of the vertebral artery (VA) causes compression of the proximal cervical root of the spinal cord without leading to bony erosion and an enlarged foramen. We evaluated the clinical significance and incidence of the medial loop in the V2 segment of the VA.

Methods

We reviewed the records from 1000 consecutive patients who had undergone magnetic resonance imaging evaluation of the cervical spine between January 2005 and January 2008. The inclusion criteria were that over a third of the axial aspect of the VA located in the intervertebral foramen was inside the line between the most ventral points of the bilateral lateral mass, and that the ipsilateral proximal root deviated dorsally because of the medial loop of the VA. We excluded cases of bone erosion, a widened foramen at the medial loop of the VA, any bony abnormalities, tumors displacing VA, or vertebral fractures. The medical records were reviewed retrospectively to search for factors of clinical significance.

Results

In six patients (0.6%), the VA formed a medial loop that caused compression of the proximal cervical root. One of these patients had the cervical radiculopathy that developed after minor trauma but the others did not present with cervical radiculopathy related to the medial loop of the VA.

Conclusion

The medial loop of the VA might have a direct effect on cervical radiculopathy. Therefore, this feature should be of critical consideration in preoperative planning and during surgery.