Clinical and radiographic outcomes using third-generation bioactive glass as a bone graft substitute for multi-level anterior cervical discectomy and fusion-a retrospective case series study.

BACKGROUND: Bioactive glasses have unique bone forming properties that have been used as a bone graft substitute for anterior cervical discectomy and fusions (ACDFs). Bone graft substitutes are used for achieving fusion while simultaneously avoiding donor site morbidity of iliac crest autograft. In this study, our principal intention is to assess the clinical and radiographic outcomes in patients with multi-level cervical disc disease undergoing ACDF using a third-generation bioactive glass as a bone graft substitute. METHODS: A retrospective case series study was performed of patients who underwent primary multi-level instrumented fusions for degenerative cervical disc disease with bioactive glass bone graft substitute between May 2016 and December 2017 by a single fellowship-trained spine surgeon. All patients were treated with a porous PEEK interbody spacer and with a third-generation bioactive glass synthetic bone graft substitute. Patients were assessed pre-operatively, immediately following surgery, and at 3, 6, 12, and 24 months. Accepted standard outcome measures were applied to evaluate preoperative and postoperative metrics, including Visual Analog Scale neck pain and arm pain, and Neck Disability Index. Dynamic lateral radiographs were used to assess sagittal alignment, disc space height, arthrodesis status, osseous integration, and implant migration. Sagittal plane angulation was measured by Cobb's criteria. RESULTS: Thirty-nine patients underwent multi-level instrumented fusions: seventeen (43%) were two-level; 12 (31%) were three-level; 9 (23%) were four-level; and 1 (3%) was five-levels. All patients were followed for a minimum of 6 months for mean of 16.0 months (range, 6 to 36 months); none were lost to follow-up. Significant improvements from preoperative scores in Neck Disability Index scores as well as neck and arm visual analog scale pain scores were realized. All patients either maintained or improved their neurological status. Radiographically, all patients were fused by 6 months postoperatively and showed improvement in fusion segment lordosis (Pre-Post and Pre-Final P<0.001), C2-C7 lordosis angle (Pre-Post and Pre-Final P<0.001), T1 slope (Pre-Post P=0.01, Pre-Final P=0.07) and maintenance of disc height (Post-Final P=0.02). There were no adverse events, infections, or reoperations. CONCLUSIONS: Third-generation bioactive glass synthetic graft is a viable alternative to allograft or autograft in the setting of multi-level instrumented fusions for achieving improved clinical and radiographic outcomes.

Clinical experience with the use of a spherical bioactive glass putty for cervical and lumbar interbody fusion.

BACKGROUND: A retrospective clinical case series study was conducted to evaluate the use of a novel, spherical bioactive glass bone graft (BioSphere Putty) as a graft material for cervical and lumbar interbody fusion. METHODS: Data was collected from a single surgeon using BioSphere Putty along with standardized hardware in anterior cervical decompression and fusion (ACDF), transforaminal lumbar interbody fusion (TLIF), and anterior lumbar interbody fusion (ALIF) surgical procedures. BioSphere Putty was used in combination with cancellous allograft (ACDF and ALIF) or in combination with autograft (TLIF). Clinical outcomes were assessed at 1- and 2-year using radiographic imaging and the visual analog pain scale (VAS). VAS scores at the 1- and 2-year follow-up periods were statistically compared to pre-operative scoring. Successful clinical outcomes were determined by a combination of the presence of a complete radiographic fusion and a decrease in VAS at 1-year and 1- and 2-year follow-up periods. RESULTS: The retrospective review of the patient data identified 248 cases that had either 1- or 1- & 2-year follow-up. This consisted of 115 ACDF procedures and 133 lumbar fusion procedures. Lumbar fusion cases were further sub-grouped with 103 patients undergoing TLIF procedures and 30 patients undergoing ALIF procedures. The global results for the series as a whole showed clinical outcomes comparative to other advanced biologic bone grafts. Radiographically all patients demonstrated fusion (100% fusion rate) and there were no clinical adverse events, infections, or graft-related complications in any of the patients in the series. One-year VAS scores were consistent with historical norms and demonstrated significant decreases in pre-operative pain for both ACDF patients (78% decrease) and lumbar patients (66% decrease TLIF/ALIF) (t test, P<0.05). By 2 years, VAS scores continued to drop with significant decreases for the ACDF patients (96%), TLIF patients (82%), and ALIF patients (80%) (t test, P<0.05). VAS scores were also assessed for each individual patient. The data showed a VAS score decrease from pre-operative levels in 93% of the ACDF patients and 89% of the lumbar patients. Combined with the 100% radiographic fusion rate in all patients, this resulted in a in a clinical success rate of 93% for the ACDF patients and 89% for the lumbar patients. CONCLUSIONS: The results of this clinical case series demonstrated that BioSphere Putty is a clinically effective and versatile synthetic bone graft material in the spine.

Impaction durability of porous polyether-ether-ketone (PEEK) and titanium-coated PEEK interbody fusion devices.

BACKGROUND CONTEXT: Various surface modifications, often incorporating roughened or porous surfaces, have recently been introduced to enhance osseointegration of interbody fusion devices. However, these topographical features can be vulnerable to damage during clinical impaction. Despite the potential negative impact of surface damage on clinical outcomes, current testing standards do not replicate clinically relevant impaction loading conditions. PURPOSE: The purpose of this study was to compare the impaction durability of conventional smooth polyether-ether-ketone (PEEK) cervical interbody fusion devices with two surface-modified PEEK devices that feature either a porous structure or plasma-sprayed titanium coating. STUDY DESIGN/SETTING: A recently developed biomechanical test method was adapted to simulate clinically relevant impaction loading conditions during cervical interbody fusion procedures. METHODS: Three cervical interbody fusion devices were used in this study: smooth PEEK, plasma-sprayed titanium-coated PEEK, and porous PEEK (n=6). Following Kienle et al., devices were impacted between two polyurethane blocks mimicking vertebral bodies under a constant 200 N preload. The posterior tip of the device was placed at the entrance between the polyurethane blocks, and a guided 1-lb weight was impacted upon the anterior face with a maximum speed of 2.6 m/s to represent the strike force of a surgical mallet. Impacts were repeated until the device was fully impacted. Porous PEEK durability was assessed using micro-computed tomography (µCT) pre- and postimpaction. Titanium-coating coverage pre- and postimpaction was assessed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. Changes to the surface roughness of smooth and titanium-coated devices were also evaluated. RESULTS: Porous PEEK and smooth PEEK devices showed minimal macroscopic signs of surface damage, whereas the titanium-coated devices exhibited substantial visible coating loss. Quantification of the porous PEEK deformation demonstrated that the porous structure maintained a high porosity (>65%) following impaction that would be available for bone ingrowth, and exhibited minimal changes to pore size and depth. SEM and energy dispersive X-ray spectroscopy analysis of titanium-coated devices demonstrated substantial titanium coating loss after impaction that was corroborated with a decrease in surface roughness. Smooth PEEK showed minimal signs of damage using SEM, but demonstrated a decrease in surface roughness. CONCLUSION: Although recent surface modifications to interbody fusion devices are beneficial for osseointegration, they may be susceptible to damage and wear during impaction. The current study found porous PEEK devices to show minimal damage during simulated cervical impaction, whereas titanium-coated PEEK devices lost substantial titanium coverage.

Management of proximal femoral shaft fractures in osteopetrosis: a case series using internal fixation.

Osteopetrosis is a group of rare sclerosing bone dysplasias. Orthopedic concerns in osteopetrosis are principally related to the characteristic brittle "marble bone" in which fractures may be easily induced by relatively low-energy mechanisms. Femoral fractures are common in this patient population, and management presents a unique technical challenge. While osteopetrotic bone may be penetrated with a drill bit, the drill bit flutes are immediately filled with bone. This renders the drill ineffective, and generation of significant frictional heat can result in breakage of the drill. This case series describes the long-term management of nine osteopetrotic femoral fractures in three patients. The difficulties encountered in these cases prompted the development of a safe and efficacious technique for intramedullary fixation of these fractures.