4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

Abstract

In the future, there will be an increased number of cervical revision surgeries, including 4- and more-levels. But, there is a paucity of literature concerning the geometrical and clinical outcome in these challenging reconstructions. To contribute to current knowledge, we want to share our experience with 4- and 5-level anterior cervical fusions in 26 cases in sight of a critical review of literature. At index procedure, almost 50% of our patients had previous cervical surgeries performed. Besides failed prior surgeries, indications included degenerative multilevel instability and spondylotic myelopathy with cervical kyphosis. An average of 4.1 levels was instrumented and fused using constrained (26.9%) and non-constrained (73.1%) screw-plate systems. At all, four patients had 3-level corpectomies, and three had additional posterior stabilization and fusion. Mean age of patients at index procedure was 54 years with a mean follow-up intervall of 30.9 months. Preoperative lordosis C2-7 was 6.5 degrees in average, which measured a mean of 15.6 degrees at last follow-up. Postoperative lordosis at fusion block was 14.4 degrees in average, and 13.6 degrees at last follow-up. In 34.6% of patients some kind of postoperative change in construct geometry was observed, but without any catastrophic construct failure. There were two delayed unions, but finally union rate was 100% without any need for the Halo device. Eleven patients (42.3%) showed an excellent outcome, twelve good (46.2%), one fair (3.8%), and two poor (7.7%). The study demonstrated that anterior-only instrumentations following segmental decompressions or use of the hybrid technique with discontinuous corpectomies can avoid the need for posterior supplemental surgery in 4- and 5-level surgeries. However, also the review of literature shows that decreased construct rigidity following more than 2-level corpectomies can demand 360 degrees instrumentation and fusion. Concerning construct rigidity and radiolographic course, constrained plates did better than non-constrained ones. The discussion of our results are accompanied by a detailed review of literature, shedding light on the biomechanical challenges in multilevel cervical procedures and suggests conclusions.

Fig. 1

Case 23. A 55-years-old patient with DCI C3-7, axial neck pain, radiculopathia C6-8 left, and cervical kyphosis. There was no change in construct geometry following ACDF and stabilization with a CS-plate C3-7. A 24 months follow-up showed osseus union C3-7 and excellent clinical result. Patient also underwent correction of adult thoracic scoliosis and lumbar fusion with good clinical outcome

Fig. 2

Case 12. A 14-years-old patient with neurofibromatosis, large thoracolumbar kyphoscoliosis, total kyphosis C2-7 with a sharp local rigid kyphosis C5-6. 3-level corpectomy with NC-plate C3-7 was performed. But, neutral sagittal balance could not be resotred. There was primary plate impingement C2-3 with further increase during clinial course and some rekyphosing at C5-6. At 13 years follow-up this satisfied patient showed an excellent clinical outcome

Fig. 3

Case 33. PACS C3-6, radiculopathia C6-8 left with severe neck pain. At last follow-up there was solid osseus union following ACDF C3-7, maintained distraction using TMCs and CS-plate. There was no loss of construct geometry or lordosis. Patient showed good clinical outcome

Fig. 4

Case 17. PACS with non-instrumented ACDF C4-6. ADD at C6-7 and C3-4 with multilevel CS, radiculopathia of C6 and C7, and severe neck pain. At index procedure, hybrid technique with corpectomy of C5 and C6, and discectomy at C3-4 was performed. Intersegmental distraction was achieved using TMC at C3-4 and C4-7, packed with corpectomy site-derived bone. A NC-plate was applied. There was some early subsidience with minor plate impingement C7-T1, but no significant change of construct geometry. Of note, less lordosis was reconstructed using the rectangular cages and a non prebended plate. But, clinical outcome was good at last follow-up

Fig. 5

Case 1. Patient with multisegmental DCI and block vertebra C2-3. He underwent 4-level ACDF and stabilization with a NC-plate. Follow-up at one year showed solid fusion. Patient was satisfied and showed excellent clinical result. Note subsidience with some telescoping and screw toggling at C6-7 early during postoperative course

Fig. 6

Case 16. PACS C5-6 and esophageal compression at C6-7, multisegmental DCI. At index procedure there was a kyphotic curvature at C2-5 with some TCL C2-7 of 6°. After implant removal C5-6, ACDF C3-7 was performed and a CS-plate applied. Follow-up after 3 and 6 months depicted solid osseus union C3-7, excellent clinical result with no loss of reconstructed TCL C2-7

Fig. 7

a Case 19. left Referred patient with non-instrumented 2-level corpectomy and adjacent discectomy, infection, tracheostoma and graft dislodgement. At index procedure he showed signs of advanced myelopathy. After implant removal, 3-level corpectomy C4-6 and NC-plate stabilization was performed (left). Insufficient construct stability following the index procedure with increase of the preexisting kyphosis C3-4 and marked subsidience of the graft caudally, telescoping at C6-7 with screw toogling at C7, as well as plate impingement on C7-T1 (seen on postop radiograph) demanded posterior fusion on the fourth postop day. Afterwards, the patient showed no further change of construct geometry, osseus union C3-7, good clinical outcome with moderate posterior neck pain at 6 months follow up. b Case 26, right 52-years old myelopathic referred patient with non-instrumented ACDF C4-6, DCI C3-4 and C6-7. Following implant removal the osseus defects demanded corpectomies C4-6 and ACPS using a CS-plate system. As there was good bone quality and sufficient construct rigidity intraoperatively, the patient was not considered to undergo additional posterior stabilization. Six months follow-up depicted satisfied patient, solid osseus incorporation at the cage-bone interface, as well as no loss of construct geometry