A two-dimensional operative video of a midline-sparing para-articular approach for resection of a calcified cervical synovial cyst: A variant of the minimally invasive left C5/C6 foraminotomy

Background: Synovial cysts are rare degenerative lesions arising from facet joints that likely arise due to hypermobility, trauma, and inflammation. These lesions can calcify, making resection challenging when adjacent to critical neurovascular structures. Operative intervention classically warrants a two-level partial or complete laminectomy, or a unilateral “open” or minimally invasive medial facetectomy/foraminotomy; notably, the latter is largely equivalent to the procedure described here as a “midline sparing para-articular approach.” Case Description: This two-dimensional operative video demonstrates a minimally invasive, midline-sparing, unilateral para-articular approach (i.e., largely equivalent to a microscopic unilateral medial facetectomy/foraminotomy) for removal of a calcified cervical foraminal synovial cyst on the left at the C5/6 level. This 45-year-old female presented with several years of severe refractory neck pain radiating to the left periscapular region and upper extremity. Neuroimaging revealed a partially calcified neural foraminal mass arising from the left C5/6 ventral facet joint, contributing to severe compression of the exiting C6 nerve root. Surgical intervention, consisting of a modification of the well-documented minimally invasive modified left C5/6 medial facetectomy/foraminotomy, here alternatively labeled as a midline sparing para-articular approach, utilized microscope visualization, intraoperative neural monitoring, and neuronavigation. Key surgical steps included computed tomography-guided localization and demarcation of the left-sided C5/6 articular lesion. Next, ultrasonic bone resection maximized exposure and undercut the facet joint (i.e., excising the medial facet), while preserving joint integrity (i.e., leaving the mid and lateral facet joint intact). This was followed by microscopic dissection of the dorsal calcified synovial cyst capsule away from the ventrally compressed and foraminally exiting C6 nerve root. Careful additional attention was paid to preserve the integrity of the vertebral artery. This technique facilitated total en bloc removal of the foraminal calcified synovial cyst. The patient was discharged on postoperative day 1 with complete resolution of symptoms and no new neurological deficits. The pathology confirmed that the lesion was a calcified synovial cyst. Postoperative imaging within 24 h of the operation confirmed complete cyst resection, preservation of the mid/lateral facet joint, and stability (i.e., normal cervical alignment). Conclusion: This technical note/video describes a cervical midline-sparing para-articular approach that is largely equivalent to the well-known minimally invasive unilateral cervical medial facetectomy/foraminotomy. One of the differences is the lateral to medial surgical corridor that was established in our case, rather than the standard medial to lateral approach, which would have required more bony removal to access the calcified cyst. In this case, it was successfully utilized to remove a left-sided calcified cervical foraminal synovial cyst at the C5/6 level, while largely preserving the C5/6 facet (and therefore stability), thus avoiding the need for fusion.