Silicate-substituted calcium phosphate as a bone void filler after kyphoplasty in a young patient with multiple compression fractures due to osteogenesis imperfecta variant

Psychosocial Outcomes of Pain and Pain Management in Adults with Osteogenesis Imperfecta: A Qualitative Study

Osteogenesis imperfecta (OI) is a genetic disorder characterized by bone fragility and fractures, short stature, dental abnormalities, hearing loss, scoliosis, and chronic pain. Despite a growing literature on the functional outcomes of OI, limited research has explicitly examined the psychosocial outcomes of pain within OI. Adults with OI (N = 15) were interviewed to understand pain-related experiences through a thematic analysis of semi-structured interview data. Research team members, genetic research experts, and OI clinicians developed an interview guide focused on topics related to pain and mental health challenges. Participants' transcripts were coded by two independent coders; codes were then merged across coders and quotation outputs were subsequently abstracted (paraphrased then thematically classified) to identify common themes. Themes related to pain management variability regarding pain type, pain risk management and accessibility, pain outcomes (e.g., behavior, cognitive, affective), and pain exacerbating factors (e.g., individual, contextual) were identified. Participants reported chronic and acute pain, and despite the inaccessibility and stigmatization of pain medications (e.g., opioids), pharmacological treatments were the most common pain management approach. Participants reported negative pain outcomes, such as limited daily functioning and activity participation, fear, anger, anxiety, depression, and difficulty concentrating. Lastly, participants suggested that lack of physician and community knowledge on chronic pain in OI indirectly exacerbates both subjective pain intensity and outcomes. Although limited by a small, nondiverse sample, the current study provides valuable exploration of the unique pain experiences of adults with OI that may have implications for proactive management, treatment development, and clinician training.

Radiographic and CT Evaluation of Recombinant Human Bone Morphogenetic Protein-2-assisted Cervical Spinal Interbody Fusion

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

To radiographically demonstrate the distinct fusion pattern of recombinant human bone morphogenetic protein-2 (rhBMP-2) in the setting of anterior cervical discectomy and fusion.

SUMMARY OF BACKGROUND DATA

Studies investigating spinal fusion assisted with rhBMP-2 have yielded promising results, suggesting rhBMP-2 is an efficacious alternative to iliac crest autografts. rhBMP-2-assisted spinal fusion both hastens healing and eliminates patient morbidity from iliac crest autograft. Unique to rhBMP-assisted spinal fusion is its distinct radiographic fusion pattern as fusion is achieved. Despite promising results and increased clinical use of rhBMP-2, there remains a paucity of literature documenting this radiographic process.

MATERIALS AND METHODS

This study included 26 patients who underwent single-level anterior cervical discectomy and fusion using rhBMP-2. All data used for this study was collected from a prior FDA Investigational Device Exemption study.

RESULTS

A polyetheretherketone cage was used as an interbody disk spacer in all 26 patients. Patients were evaluated between 2 and 6 weeks after surgery and subsequently at 3, 6, 12, and 24 months postoperative. All patients underwent plain radiography at every follow-up visit, and computed tomograhy evaluation was performed at 3, 6, 12, and 24 months as part of the study protocol. Earliest fusion was observed at 3 months in 38% of patients. Likely fusion was observed in all patients by 12 months postoperative.

CONCLUSIONS

rhBMP-2 leads to both successful interbody fusion and an enhanced fusion rate with unique imaging characteristics. Additional characteristics of BMP observed in 100% of patients included prevertebral soft-tissue swelling and early endplate resorption. Other common features included polyetheretherketone cage migration, heterotopic bone formation and cage subsidence.

Efficacy of i-Factor Bone Graft versus Autograft in Anterior Cervical Discectomy and Fusion: Results of the Prospective, Randomized, Single-blinded Food and Drug Administration Investigational Device Exemption Study

STUDY DESIGN

A prospective, randomized, controlled, parallel, single-blinded noninferiority multicenter pivotal FDA IDE trial.

OBJECTIVE

The objective of this study was to investigate efficacy and safety of i-Factor Bone Graft (i-Factor) compared with local autograft in single-level anterior cervical discectomy and fusion (ACDF) for cervical radiculopathy.

SUMMARY OF BACKGROUND DATA

i-Factor is a composite bone substitute material consisting of the P-15 synthetic collagen fragment adsorbed onto anorganic bone mineral and suspended in an inert biocompatible hydrogel carrier. P-15 has demonstrated bone healing efficacy in dental, orthopedic, and nonhuman applications.

METHODS

Patients randomly received either autograft (N = 154) or i-Factor (N = 165) in a cortical ring allograft. Study success was defined as noninferiority in fusion, Neck Disability Index (NDI), and Neurological Success endpoints, and similar adverse events profile at 12 months.

RESULTS

At 12 months (follow-up rate 87%), both i-Factor and autograft subjects demonstrated a high fusion rate (88.97% and 85.82%, respectively, noninferiority P = 0.0004), significant improvements in NDI (28.75 and 27.40, respectively, noninferiority P < 0.0001), and high Neurological Success rate (93.71% and 93.01%, respectively, noninferiority P < 0.0001). There was no difference in the rate of adverse events (83.64% and 82.47% in the i-Factor and autograft groups, respectively, P = 0.8814). Overall success rate consisting of fusion, NDI, Neurological Success and Safety Success was higher in i-Factor subjects than in autograft subjects (68.75% and 56.94%, respectively, P = 0.0382). Improvements in VAS pain and SF-36v2 scores were clinically relevant and similar between the groups. A high proportion of patients reported good or excellent Odom outcomes (81.4% in both groups).

CONCLUSION

i-Factor has met all four FDA mandated noninferiority success criteria and has demonstrated safety and efficacy in single-level ACDF for cervical radiculopathy. i-Factor and autograft groups demonstrated significant postsurgical improvement and high fusion rates.

LEVEL OF EVIDENCE

1.

Preconditioned 70S30C bioactive glass foams promote osteogenesis in vivo

Bioactive glass scaffolds (70S30C; 70% SiO2 and 30% CaO) produced by a sol-gel foaming process are thought to be suitable matrices for bone tissue regeneration. Previous in vitro data showed bone matrix production and active remodelling in the presence of osteogenic cells. Here we report their ability to act as scaffolds for in vivo bone regeneration in a rat tibial defect model, but only when preconditioned. Pretreatment methods (dry, pre-wetted or preconditioned without blood) for the 70S30C scaffolds were compared against commercial synthetic bone grafts (NovaBone® and Actifuse®). Poor bone ingrowth was found for both dry and wetted sol-gel foams, associated with rapid increase in pH within the scaffolds. Bone ingrowth was quantified through histology and novel micro-CT image analysis. The percentage bone ingrowth into dry, wetted and preconditioned 70S30C scaffolds at 11 weeks were 10±1%, 21±2% and 39±4%, respectively. Only the preconditioned sample showed above 60% material-bone contact, which was similar to that in NovaBone and Actifuse. Unlike the commercial products, preconditioned 70S30C scaffolds degraded and were replaced with new bone. The results suggest that bioactive glass compositions should be redesigned if sol-gel scaffolds are to be used without preconditioning to avoid excess calcium release.

Spinal Fusion of an Unstable Atlantoaxial Fracture in a Completely Tetraplegic Patient Using Silicate-Substituted Calcium Phosphate

Bone graft harvesting from the iliac crest constitutes the gold standard in spinal surgery due to its osteogenic, osteoconductive and osteoinductive properties. Large amounts of autograft can provoke complications like donor site morbidity, pain and the need for a second operation. Therefore, research into bone graft substitutes is of great interest. Silicate-substituted calcium phosphate (Actifuse(TM) Synthetic Bone Graft, ApaTech Ltd, London) was used in combination with morselized corticocancellous graft in a transarticular stabilization (modified Magerl) of a completely tetraplegic patient with an unstable atlantoaxial fracture. Computed tomography showed bone bridging between the segment C1/C2, the surface of the implant and the remodeled bone at follow-up at 8 months. The use of silicate-substituted calcium phosphate as a bone graft extender in spinal surgery could be an alternative to autografting from the iliac crest. Vegetative symptoms are often underestimated but can be triggered by donor site morbidity or pain in patients after spinal cord injury.

Evaluation of a silica-containing bone graft substitute in a vertebral defect model

Orthopedic and spine surgeons are in need of supplements or replacements for autograft. We investigated the histological properties of three formulations of Calcium Sodium Phosphosilicate [calcium sodium phosphosilicate putty with or without autograft and NovaBone 45S5 Bioglass particulate (NovaBone, LLC, Jacksonville, FL)] using a sheep vertebral bone void model. Bone voids were surgically created in L3, L4, and L5 in each of 22 sheep, and the voids were filled with one of the tested biomaterials or left empty as a control. Histological evaluations were performed at either: 0, 6, or 12 weeks after surgery. Undecalcified sections were digitized, and the areas of the original defect and new bone were quantified. Decalcified sections were evaluated qualitatively. Histomorphometry showed a significant increase in the amount of bone between 6 and 12 weeks in all groups, but there was no significant difference in new bone formation among the formulations or between any formulation and the empty defects. The granules of all three formulations were associated with an inflammatory reaction. Many of the particles appear to have a hollow center, and the narrow tunnel through the center of the particles was sometimes associated with acute inflammation especially at 6 weeks. These particles were also associated with chronic inflammation at both 6 and 12 weeks, although the extent of inflammation decreased between 6 and 12 weeks. The search for the optimum bone graft substitute/extender will continue.

The role of kyphoplasty in the management of osteogenesis imperfecta: risk or benefit?

Kyphoplasty is a recognized treatment option in the management of symptomatic osteoporotic compression fractures, osteolytic vertebral metastases or haemangioma. To our knowledge, kyphoplasty with polymethylmethacrylate in a patient with type I osteogenesis imperfecta (OI) and a vertebral compression fracture has not been reported so far. We report on a 58-year-old patient with type I OI and a vertebral compression fracture at L2 with undislocated posterior vertebral wall and an additional older L1 fracture. Because of severe back pain resistant to conservative therapy over 5 months the indication for percutaneous kyphoplasty was made. Preoperative adjacent endplates of L2 were nearly parallel. Radiologically a minimal loss of height of the L2 vertebra was seen without adjacent fractures at 9 months follow-up. A slight increase of the preoperative kyphotic angle of overlying vertebrae L1 (8.7 degrees/10.3 degrees) and T12 (10.4 degrees/11.0 degrees) was apparent. The visual analogue scale showed decrease of low back pain from 10 to 2 allowing mobilization with a walking frame. Kyphoplasty constitutes a minimal invasive therapeutic alternative in the treatment of vertebral fractures in type I OI and pain, resistant to conservative treatment. Similar to the results of osteoporotic fractures the immediate reduction of pain and stabilization of the fracture in undislocated fragments can be achieved. No adjacent fractures occurred 9 months postoperatively after kyphoplasty in type I OI. Preoperative parallelism of the endplates seems to protect from adjacent fractures.