High posterior cervical fusion rates with iliac autograft and Nanoss/bone marrow aspirate

Abstract

Background: Patients with severe cervical multilevel stenosis and an adequate lordotic curvature often undergo multilevel laminectomies with posterior instrumented fusions. Although the "gold standard" for the fusion mass remains iliac crest autograft, many require additional volume provided by bone graft expanders. Here, we studied the fusion rates for 32 patients undergoing multilevel cervical laminectomy and vertex/rod/eyelet/titanium cable fusions utilizing lamina/iliac autograft and the bone graft expander Nanoss (RTI Surgical, Alachua, FL, USA) with autogenous bone marrow aspirate (BMA).

Methods: Thirty-two patients, averaging 63.0 years of age, presented with severe cervical myeloradiculopathy (average Nurick Grade 4.4). Magnetic resonance (MR) studies documented 2-3-level high intrinsic cord signals, whereas computed tomography (CT) scans confirmed marked stenosis and ossification of the posterior longitudinal ligament (OPLL)/ossification of the yellow ligament (OYL). Patients underwent multilevel lamnectomies/instrumented fusions, and were followed up for an average of 2.7 years.

Results: Multilevel laminectomies (2.8 levels) and average 7.8-level vertex/rod/eyelet/cable fusions were performed utilizing lamina/iliac crest autograft and Nanoss/BMA. Fusion was confirmed on X-ray/CT studies an average of 4.7 months postoperatively in 31 of 32 patients (97%); there was just one pseudarthrosis requiring secondary surgery. The only other complication was a delayed transient C5 palsy that fully resolved in 6 postoperative months.

Conclusions: Thirty-two severely myelopathic underwent 2.8-level cervical laminectomies/7.8 level fusions utilizing lamina/iliac autograft and Nanoss/BMA. Fusion was documented on both dynamic X-ray and CT studies in 31 of 32 (97%) patients an average of 4.7 months postoperatively. Nanoss/BMA appears to be a safe and effective bone graft expander that can be utilized for posterior cervical fusions.

Keywords: Bone graft expander; Nanoss; bone marrow aspirate (BMA); high fusion rates; posterior cervical fusions.

Figure 1

This preoperative cervical T2-weighted sagittal midline MR documented posterolateral cord compression at the C3–C4 level and C6–C7 levels. Here, lamienctomies at C3 and C6/C7 resulted in sufficient posterolateral cord decompression with resection of ossification of the yellow ligament and decompression of dorsolateral shingling of the respective laminae. Here, laminectomy of C3, C6, and C7 with C2–T2 posterior fusion resulted in adequate cord decompression

Figure 2

Preoperative 2D-sagittal CT documenting stenosis C45/56/67 associated with ossification of the posterior longitudinal ligament and dorsolateral shingling of the laminae. Here a laminectomy of C5, C6, C7 with posterior fusion C2–T2 resulted in adequate cord decompression

Figure 3

The preoperative soft tissue sagittal 2D-CT documented marked spinal stenosis at the C3–C4 level attributed to anterior ossification of the posterior longitudinal ligament (OPLL) and dorsolateral inward shingling/stenosis involving the C3 and C4 laminae. Here, a laminectomy of C3, C4 with posterior fusion C2–C5/C6 adequately decompressed the spinal cord

Figure 4

On this preoperative axial noncontrast CT study obtained at the C5–C6 level, there is marked ventral ossification of the posterior longitudinal ligament accompanied by dorsolateral inward shingling of both the C5 and C6 laminae (note both laminae are seen on the same image posteriorly). The combined pathology reduced the AP diameter of the spinal canal to less than 6 mm

Figure 5

The postoperative plain X-ray documented the laminectomy defects at the C5, C6 levels, and the posterior vertex/rod/eyelet/titanium cable system applied to the spinous processes of C2, C3, C4, C7, T1, and T2. Note there was some pullout of C2 but the remaining cables remained in place until the patient fused without the need for further surgery

Figure 6

The 6-week postoperative T2 sagittal MR study documented excellent decompression of the spinal cord following laminectomy of C5, C6 with posterior vertex/rod/eyelet/titanium cable fusion C2T2. Note in this case the preoperative increased signal in the cord at the C5–C6 level fully resolved

Figure 7

On the 6-month postoperative axial CT, fusion over the laminae/continuity of the bone fragments attributed to lamina/iliac crest autograft and Nanoss/BMA/ was noted

Figure 8

Parasagittal 6-month postoperative 2D-CT documented fusion across multiple lateral laminae and facet joints utilizing lamina/iliac crest autograft and Nanoss/BMA for posterolateral C2-T2 fusion.