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.
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.