MINIMALLY INVASIVE SINGLE-DOOR PLATE LAMINOPLASTY WITH LATERAL MASS SCREW FIXATION FOR THE UNSTABLE SEGMENT. REPORT OF TWO CASES WITH LONG FOLLOW-UP

ABSTRACT Objective: To report two cases of multilevel cervical spondylotic myelopathy with monosegmental instability, in which we performed a minimally invasive microsurgical transmuscular approach with tubular retractors to create a single-door plate laminoplasty combined with fixation of the unstable segment with lateral mass screws. Methods: The surgical procedures were performed by the senior author. In both patients, the follow-up was performed using the Oswestry Disability Index (ODI), the Visual Analogue Scale for neck and radicular pain (radVAS, neckVAS), the Neck Disability Index (NDI) and the Short Form 36 (SF-36), in the preoperative (preop) and postoperative (postop) periods, and at 1, 3, 6, 12, 18 and 24 months. A radiological evaluation also was performed, which included AP, lateral and flexion-extension films at 6, 12 and 24 months and CT-scan at 12 months. Results: Case 1 - preop ODI: 40%, 24 months postop ODI: 4%; preop radVAS: 7, 24 months radVAS: 0; preop neckVAS: 8, postop 24 months neckVAS: 0; preopNDI: 43%, 24 months PostopNDI: 8%; SF-36 - preop Physical Functioning (PF): 40, preop Vitality (VT): 40, preop Emotional role functioning (RE): 33.3, Bodily pain (BP): 51, General Health (GH): 57, Social Functioning (SF): 75; postop PF: 95, VT: 95, RE: 100, BP: 74, GH: 87, SF: 100. Case 2 - preopODI: 46%, 24 months postopODI: 10%; preop radVAS: 7, 24m radVAS: 0; preop neckVAS: 9, postop 24 months neckVAS: 0; preopNDI: 56%, 24 months PostopNDI: 15%; SF-36 - preop PF: 39, VT: 45, RE: 33.3, BP: 50, GH: 49, SF: 70; postop PF: 90, VT: 100, RE: 100, BP: 82, GH: 87, SF: 100. No complications, cervical instability or signs of failed surgery were found trough and at final follow-up at 24 months. We found significant clinical improvement in both patients. Conclusions: Minimally invasive cervical laminoplasty combined with lateral mass screw fixation for the unstable segment is a useful technique in cases with multilevel cervical spondylotic myelopathy associated with monosegmental instability. Additional comparative studies are needed to establish its efficacy.