Cellular allograft for multilevel stand-alone anterior cervical discectomy and fusion

Cellular Bone Matrix in Spine Surgery - Are They Worth the Risk: A Systematic Review

STUDY DESIGN

Systematic Review.

OBJECTIVE

To review the literature for complications and outcomes after the implantation of cellular bone matrix (CBM) during spine fusion.

METHODS

The PubMed database was queried from inception to January 31, 2023 for any articles that discussed the role of and identified a specific CBM in spinal fusion procedures. Adverse events, reoperations, methods, and fusion rates were collected from all studies and reported.

RESULTS

Six hundred articles were identified, of which 19 were included that reported outcomes of 7 different CBM products. Seven studies evaluated lumbar fusion, 11 evaluated cervical fusion, and 1 study reported adverse events of a single CBM product. Only 4 studies were comparative studies while others were limited to case series. Fusion rates ranged from 68% to 98.7% in the lumbar spine and 87% to 100% in the cervical spine, although criteria for radiographic fusion was variable. While 7 studies reported no adverse events, there was no strict consensus on what constituted a complication. One study reported catastrophic disseminated tuberculosis from donor contaminated CBM. The authors of 14 studies had conflicts of interest with either the manufacturer or distributor for their analyzed CBM.

CONCLUSIONS

Current evidence regarding the use of cellular bone matrix as an osteobiologic during spine surgery is weak and limited to low-grade non-comparative studies subject to industry funding. While reported fusion rates are high, the risk of severe complications should not be overlooked. Further large clinical trials are required to elucidate whether the CBMs offer any benefits that outweigh the risks.

Anterior Cervical Discectomy and Fusions Supplemented With Cellular or Noncellular Allografts Have Similar Radiographic Fusion and Clinical Outcomes

STUDY DESIGN

A retrospective, single-center study.

OBJECTIVE

The aim of this study was to assess radiographic fusion after anterior cervical discectomy and fusion (ACDF) supplemented with either demineralized bone matrix or ViviGen in a polyetheretherketone biomechanical interbody cage.

SUMMARY OF BACKGROUND DATA

Cellular and noncellular allografts are utilized as adjuncts in attempts to improve fusion after ACDF. The purpose of this study was to assess radiographic fusion and clinical outcomes after ACDF supplemented with cellular or noncellular allografts.

MATERIALS AND METHODS

A single surgeon's clinical practice database was interrogated for consecutive patients who underwent a primary ACDF using cellular or noncellular allograft from 2017 to 2019. These subjects were matched by age, sex, body mass index, smoking status, and levels operated. Patient demographic and preoperative and postoperative patient-reported outcome measures (PROMs) including Visual Analog Scale Pain, Neck Disability Index, EuroQol-5 Dimension (EQ-5D), Patient-Reported Outcomes Measurement Information System (PROMIS), and Eating Assessment Tool 10 were collected preoperatively and at 3, 6, and 12 months postoperatively. Radiographic evidence of fusion was determined by <2 mm motion between spinous processes on flexion and extension radiographs and assessing bony bridging at 3, 6, and 12 months postoperatively.

RESULTS

There were 68 total patients, with 34 patients in each group, and 69 and 67 operative levels in the cellular and noncellular allograft groups, respectively. There was no difference in age, sex, body mass index, or smoking status between groups ( P >0.05). There was no difference in number of 1-level, 2-level, 3-level, or 4-level ACDFs between cellular and noncellular groups ( P >0.05). At 3, 6, and 12 months postoperatively, there was no difference in the percent of operated levels with <2 mm motion between spinous processes, complete bony bridging, or both <2 mm motion and complete bony bridging in the cellular and noncellular groups ( P >0.05). There was no difference in the number of patients fused at all operated levels at 3, 6, or 12 months postoperatively ( P >0.05). No patient required revision ACDF for symptomatic pseudarthrosis. There was no significant difference in PROMs between the cellular and noncellular groups at 12 months postoperatively except for improved EQ-5D and PROMIS-physical in the cellular compared with noncellular group ( P =0.03).

CONCLUSIONS

Similar radiographic fusion rates were achieved with cellular and noncellular allografts at all operated levels with similar PROMs in the cellular and noncellular groups at 3, 6, and 12 months postoperatively. Thus, ACDFs supplemented with cellular allograft demonstrate adequate radiographic fusion rates when compared with noncellular allografts with similar patient outcomes.

LEVEL OF EVIDENCE

Level III.

Characterization of an advanced viable bone allograft with preserved native bone-forming cells

Bone grafts are widely used to successfully restore structure and function to patients with a broad range of musculoskeletal ailments and bone defects. Autogenous bone grafts are historically preferred because they theoretically contain the three essential components of bone healing (ie, osteoconductivity, osteoinductivity, and osteogenicity), but they have inherent limitations. Allograft bone derived from deceased human donors is one alternative that is also capable of providing both an osteoconductive scaffold and osteoinductive potential but, until recently, lacked the osteogenic component of bone healing. Relatively new, cellular bone allografts (CBAs) were designed to address this need by preserving viable cells. Although most commercially-available CBAs feature mesenchymal stem cells (MSCs), osteogenic differentiation is time-consuming and complex. A more advanced graft, a viable bone allograft (VBA), was thus developed to preserve lineage-committed bone-forming cells, which may be more suitable than MSCs to promote bone fusion. The purpose of this paper was to present the results of preclinical research characterizing VBA. Through a comprehensive series of in vitro and in vivo assays, the present results demonstrate that VBA in its final form is capable of providing all three essential bone remodeling properties and contains viable lineage-committed bone-forming cells, which do not elicit an immune response. The results are discussed in the context of clinical evidence published to date that further supports VBA as a potential alternative to autograft without the associated drawbacks.

Comparison of anterior cervical discectomy and fusion versus anterior cervical corpectomy and fusion in the treatment of localized ossification of the posterior longitudinal ligament

BACKGROUND

The retrospective study was conducted to compare the efficacy of anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) for localized ossification of the posterior longitudinal ligament (OPLL) by evaluating clinical and radiologic outcomes.

METHODS

We reviewed 151 patients to assess the effects of treatment for one or two levels localized OPLL. Perioperative parameters, such as blood loss, operation time and complications, were recorded. Radiologic outcomes, such as the occupying ratio (OR), fusion status, cervical lordosis angle, segmental angle, disc space height, T1 slope, and C2-C7 sagittal vertical axis (SVA), were assessed. Clinical indices, such as the JOA scores and VAS scores, were investigated to compare the two surgical options.

RESULTS

There were no significant differences in the JOA scores or VAS scores between the two groups (p > 0.05). The operation time, volume of blood loss and incidence of dysphagia were significantly less in the ACDF group than in the ACCF group (p < 0.05). In addition, cervical lordosis, segmental angle and disc space height were significantly different from their preoperative evaluations. No adjacent segment degenerated in the ACDF group. The subsidence rates of implants were 5.2% in the ACDF group and 28.4% in the ACCF group. The degeneration of the ACCF group was 4.1%. The incidence of CSF leaks was 7.8% in the ACDF group and 13.5% in the ACCF group. All the patients ultimately achieved successful fusion.

CONCLUSION

Although both options achieved satisfactory primary clinical and radiographic efficacies, ACDF was associated with a shorter surgical procedure, less intraoperative blood loss, better radiologic outcomes, and lower incidence of dysphagia than ACCF.