12-Month clinical and radiographic outcomes of ViBone viable bone matrix in patients undergoing cervical and lumbar spinal fusion surgery.

BACKGROUND: To investigate the clinical safety and efficacy of ViBone® Viable Bone Matrix (VBM), a next generation cellular bone matrix allograft that comprises all three essential bone-forming components: osteogenic, osteoinductive, and osteoconductive factors, and is optimized to enhance cell viability and bone formation. METHODS: This was a multi-center, prospective, post-market study evaluating the safety and efficacy of ViBone VBM in patients undergoing 1-3 level anterior cervical discectomy and fusion or lumbar interbody fusion surgery. Patients were evaluated at baseline, 6-month, and 12-month follow-up clinically and radiographically. Clinical assessment included Visual Analog Scale for pain (VAS-pain), the Neck Disability Index (NDI) for patients with cervical pathologies, and the Oswestry Disability Index (ODI) for patients with lumbar pathologies. Fusion success defined by an independent radiologist was determined radiographically by plain films. RESULTS: Clinical outcomes evaluated with VAS-pain, NDI, and ODI scales were improved significantly at 6 and 12 months compared to baseline. All patients reached clinically significant improvements at 12 months. There were no adverse events or infections attributed to ViBone VBM. At 12 months, the fusion rate per patient was 88.1% in cervical and 97.6% in lumbar patients, while per-level fusion was 98.5% for cervical and 100% for lumbar segments. CONCLUSIONS: Patients undergoing cervical and lumbar spinal fusion implanted with ViBone VBM demonstrated favorable outcomes at 6 months and 12 months as measured by subjective clinical measures and radiographic fusion rates. Trial registration This study was registered as NCT03425682 on 1/29/2018.

Femoral nerve neuromonitoring for lateral lumbar interbody fusion surgery.

BACKGROUND CONTEXT: The transpsoas lateral lumbar interbody fusion (LLIF) technique is an effective alternative to traditional anterior and posterior approaches to the lumbar spine; however, nerve injuries are the most reported postoperative complication. Commonly used strategies to avoid nerve injury (eg, limiting retraction duration) have not been effective in detecting or preventing femoral nerve injuries. PURPOSE: To evaluate the efficacy of emerging intraoperative femoral nerve monitoring techniques and the importance of employing prompt surgical countermeasures when degraded femoral nerve function is detected. STUDY DESIGN/SETTING: We present the results from a retrospective analysis of a multi-center study conducted over the course of 3 years. PATIENT SAMPLE: One hundred and seventy-two lateral lumbar interbody fusion procedures were reviewed. OUTCOME MEASURES: Intraoperative femoral nerve monitoring data was correlated to immediate postoperative neurologic examinations. METHODS: Femoral nerve evoked potentials (FNEP) including saphenous nerve somatosensory evoked potentials (snSSEP) and motor evoked potentials with quadriceps recordings were used to detect evidence of degraded femoral nerve function during the time of surgical retraction. RESULTS: In 89% (n=153) of the surgeries, there were no surgeon alerts as the FNEP response amplitudes remained relatively unchanged throughout the surgery (negative group). The positive group included 11% of the cases (n=19) where the surgeon was alerted to a deterioration of the FNEP amplitudes during surgical retraction. Prompt surgical countermeasures to an FNEP alert included loosening, adjusting, or removing surgical retraction, and/or requesting an increase in blood pressure from the anesthesiologist. All the cases where prompt surgical countermeasures were employed resulted in recovery of the degraded FNEP amplitudes and no postoperative femoral nerve injuries. In two cases, the surgeons were given verbal alerts of degraded FNEPs but did not employ prompt surgical countermeasures. In both cases, the degraded FNEP amplitudes did not recover by the time of surgical closure, and both patients exhibited postoperative signs of sensorimotor femoral nerve injury including anterior thigh numbness and weakened knee extension. CONCLUSIONS: Multimodal femoral nerve monitoring can provide surgeons with a timely alert to hyperacute femoral nerve conduction failure, enabling prompt surgical countermeasures to be employed that can mitigate or avoid femoral nerve injury. Our data also suggests that the common strategy of limiting retraction duration may not be effective in preventing iatrogenic femoral nerve injuries.

Video-assisted thoracoscopic surgery compared with thoracotomy: early and late follow-up of radiographical and functional outcome.

BACKGROUND CONTEXT: Video-assisted thoracoscopic surgery (VATS) is a new technique that allows for access to anterior spinal pathology using a minimally invasive approach. Proponents of this procedure argue that anterior thoracic spine surgery can be performed with the same accuracy and completeness as is possible by the conventional open approach but through much smaller skin and muscle incisions. Advantages of VATS include decreased blood loss, shorter hospital stay, and improved cosmesis. PURPOSE: To detect if VATS is equally as effective as open thoracotomy, both combined with instrumented posterior spinal fusion, with respect to fusion rate, percent curve correction, and functional outcome. STUDY DESIGN: Retrospective case control. PATIENT SAMPLE: Seventeen patients underwent VATS/instrumented posterior spinal fusion for thoracic curvatures exceeding 50 degrees . A control cohort of patients that were age matched, sex matched, and curve magnitude matched underwent open thoracotomy/instrumented posterior spinal fusion. OUTCOME MEASURES: Percentage of curve correction, fusion rate, intraoperative and postoperative clinical parameters, and functional outcome scores. METHODS: Preoperative and postoperative radiographs were analyzed to calculate the percentage of major curve correction in the coronal and sagittal planes as well as the rate of fusion. In addition, operative reports and medical records were analyzed for the following outcomes: estimated operative blood loss, length of surgery, chest tube output, length of hospitalization, and complications. Average follow-up time was 26 months in the VATS group and 27 months in the thoracotomy group. Finally, functional outcome was assessed using the Scoliosis Research Society (SRS-22) and Oswestry Disability Index (ODI) scoring system. RESULTS: The VATS group (mean age, 30) averaged 5.4 anterior levels and 11 posterior levels fused. The thoracotomy group (mean age, 32) averaged 5.8 anterior levels and 12 posterior levels fused. Estimated blood loss was nearly identical for the posterior procedures in both groups, whereas the anterior blood loss was significantly higher in the thoracotomy group as compared with the VATS group (541 cc vs. 288 cc). Operative time did not differ significantly between the two cohorts. Percent curve correction immediately postoperative (52% correction VATS; 51% correction thoracotomy) as well as at the 2-year follow-up (50% VATS and 54% thoracotomy) was nearly identical. There was no difference in postoperative ODI (p=.6) or SRS scores (p=.5) between groups. Complications were frequent but not significantly different between the two groups (p=.3). CONCLUSION: VATS is equally effective as thoracotomy with respect to fusion rate, major curve correction, and functional outcome scores. Although a decrease in operative blood loss was seen in the VATS patients, this was not clinically significant.

Comparison of posterolateral lumbar fusion rates of Grafton Putty and OP-1 Putty in an athymic rat model.

STUDY DESIGN: Posterolateral lumbar spine fusions in athymic rats. OBJECTIVES: To compare spine fusion rates of two different osteoinductive products. SUMMARY OF BACKGROUND DATA: Many osteoinductive bone graft alternatives are available. Grafton (a demineralized bone matrix [DBM]) and Osteogenic Protein-1 (OP-1, an individual recombinant bone morphogenetic protein) are two such alternatives. The relative efficacy of products from these two classes has not been previously studied. The athymic rat spine fusion model has been validated and demonstrated useful to minimize inflammatory responses to xenogeneic or differentially expressed proteins such as those presented by DBMs of human etiology. METHODS: Single-level intertransverse process fusions were performed in 60 athymic nude rats with 2 cc/kg of Grafton or OP-1 Putty. Half of each study group was killed at 3 weeks and half at 6 weeks. Fusion masses were assessed by radiography, manual palpation, and histology. RESULTS: At 3 weeks, manual palpation revealed a 13% fusion rate with Grafton and a 100% fusion rate with OP-1 (P = 0.0001). At 6 weeks, manual palpation revealed a 39% fusion rate of with Grafton and a 100% fusion rate with OP-1 (P = 0.0007). Similar fusion rates were found by histology at 3 and 6 weeks. Of note, one or two adjacent levels were fused in all of the OP-1 animals and none of the Grafton animals. CONCLUSIONS: Significant differences between the ability of Grafton and OP-1 to induce bone formation in an athymic rat posterolateral lumbar spine fusion model were found.

Posterolateral lumbar fusions in athymic rats: characterization of a model.

BACKGROUND CONTEXT: The athymic rat has been used to study the role of osteoinductive products in spinal fusions. This small animal model has been advocated to minimize potential inflammatory responses to allogeneic or xenogenic proteins. Despite past experience, this model has not yet been well characterized. PURPOSE: To further define and validate a posterolateral lumbar fusion model in the athymic rat. STUDY DESIGN/SETTING: Comparison of fusions after animal survival surgery. PATIENT SAMPLE: Forty athymic and 20 normothymic rats. OUTCOME MEASURES: Manual palpation, radiography and histology at 3 and 6 weeks. METHODS: Single-level intertransverse fusions were performed at the L4-L5 level of 40 athymic rats. Twenty rats were implanted with autograft (athymic/autograft), and 20 had no graft placed (athymic/no graft). An additional 20 autograft fusions were performed on normothymic rats (normothymic/autograft). Half were sacrificed at 3 weeks; half were sacrificed at 6 weeks. RESULTS: At 3 weeks, 0% of the athymic/no graft rats fused, 20% of the athymic/autograft rats fused and 20% of the normothymic/autograft rats fused by manual palpation. At 6 weeks, 0% of the athymic/no graft rats fused, 30% of the athymic/autograft rats fused and 40% of the normothymic/autograft rats fused by manual palpation. Radiographs were of limited utility in determining fusion, and histology results were roughly concordant with those of manual palpation. CONCLUSIONS: This work further characterizes the athymic rat posterolateral lumbar fusion model. The absence of a thymus does not appear to affect autograft fusion rates, and no spontaneous fusions were seen when no graft was placed.