Intra- and Interexaminer Repeatability of Diagnostic Peri-Implant Clinical Measurement: A Pilot Study.

Despite the crucial role of examiner reliability on quality research and practice, there is still limited literature analyzing factors affecting examiner variability of peri-implant clinical measurements. The present study investigated clinical peri-implant parameters to quantify their repeatability and investigate factors that may affect their accuracy. Thirty-three implants were examined by 4 operators. Peri-implant probing depth (PD), recession (REC), and gingival index (GI) were measured for agreement and included in the analysis. Agreement was quantified using intraclass correlation coefficients (ICCs; 95% confidence interval); mixed linear and logistic regressions were used to assess additional variables. The overall interexaminer agreement was comparable between PD (0.80) and REC (0.78) but significantly worse for GI (0.45; P < .001). Similarly, the intraexaminer agreement was similar for PD (0.81) and REC (0.80) but significantly worse for GI (0.57; P < .05). The magnitude of PD did not influence the agreement. In contrast, increasing disagreement was noted for positive REC (odds ratio [OR]: 3.0), negative REC (OR: 4.8), and lower GI (OR: 4.4). The incidence of bleeding on probing and severity of GI increased for deeper PD (0.113-unit increase per millimeter). Negative and positive values of recession and lower GI were associated with increasing disagreement. Radiographic bone loss, restoration contour, and implant diameter did not affect PD accuracy in this study. In conclusion, within the limitations of the study, GI measurements presented higher variability than PD and REC did. The PD and GI were associated with one another and increased after multiple measurements.

Novel in vivo mouse model of implant related spine infection.

Post-operative spine infections are a challenge, as hardware must often be retained to prevent destabilization of the spine, and bacteria form biofilm on implants, rendering them inaccessible to antibiotic therapy, and immune cells. A model of posterior-approach spinal surgery was created in which a stainless steel k-wire was transfixed into the L4 spinous process of 12-week-old C57BL/six mice. Mice were then randomized to receive either one of three concentrations (1 × 102 , 1 × 103 , and 1 × 104 colony forming units (CFU)) of a bioluminescent strain of Staphylococcus aureus or normal saline at surgery. The mice were then longitudinally imaged for bacterial bioluminescence to quantify infection. The 1 × 102 CFU group had a decrease in signal down to control levels by POD 25, while the 1 × 103 and 1 × 104 CFU groups maintained a 10-fold higher signal through POD 35. Bacteria were then harvested from the pin and surrounding tissue for confirmatory CFU counts. All mice in the 1 × 104 CFU group experienced wound breakdown, while no mice in the other groups had this complication. Once an optimal bacterial concentration was determined, mice expressing enhanced green fluorescent protein in their myeloid cells (Lys-EGFP) were utilized to contemporaneously quantify bacterial burden, and immune response. Neutrophil fluorescence peaked for both groups on POD 3, and then declined. The infected group continued to have a response above the control group through POD 35. This study, establishes a noninvasive in vivo mouse model of spine implant infection that can quantify bacterial burden and host inflammation longitudinally in real time without requiring animal sacrifice. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:193-199, 2017.

Comparison of operating field sterility in open versus minimally invasive microdiscectomies of the lumbar spine.

BACKGROUND: Postoperative wound infection is a preventable risk that can lead to significant adverse outcomes and increased cost of care. Minimally invasive surgeries (MIS) have been found to have lower rates of postoperative infection compared with the traditional approach. To assess if the reported difference is related to intraoperative contamination or to other factors, we assessed the surgical field for sterility. METHODS: We compared 10 MIS versus 10 traditional microdiscectomies. Swabs of the operating field were obtained before and after the procedure from multiple sites in the operating room. Positive and negative controls were taken of the skin immediately before and after preparation of the incision site. All swabs were plated out on Columbia blood agar plates and grown for 48 hours. Colony counting was performed to determine growth. RESULTS: There was no statistically significant difference in the colony counts of swab sites in traditional microdiscectomies compared with MIS microdiscectomies. There was no significant contamination of the operating field using either approach. CONCLUSIONS: In this prospective study, we found that there was no significant difference in bacterial counts in swabs of operative sites in either traditional or MIS microdiscectomies, suggesting that the decreased rate of postoperative infection in the reported literature for MIS cases may be related to other factors, such as patient selection and/or postoperative care.

Kinematic Evaluation of Association between Disc Bulge Migration, Lumbar Segmental Mobility, and Disc Degeneration in the Lumbar Spine Using Positional Magnetic Resonance Imaging.

Degenerative disc disease and disc bulge in the lumbar spine are common sources of lower back pain. Little is known regarding disc bulge migration and lumbar segmental mobility as the lumbar spine moves from flexion to extension. In this study, 329 symptomatic (low back pain with or without neurological symptoms) patients with an average age of 43.5 years with varying degrees of disc degeneration were examined to characterize the kinematics of the lumbar intervertebral discs through flexion, neutral, and extension weight-bearing positions. In this population, disc bulge migration associated with dynamic motion of the lumbar spine significantly increased with increased grade of disk degeneration. Although no obvious trends relating the migration of disc bulge and angular segmental mobility were seen, translational segmental mobility tended to increase with disc bulge migration in all of the degenerative disc states. It appears that many factors, both static (intervertebral disc degeneration or disc height) and dynamic (lumbar segmental mobility), affect the mechanisms of lumbar disc bulge migration.

Osteoinductivity of commercially available demineralized bone matrix. Preparations in a spine fusion model.

BACKGROUND: Although autogenous bone is the most widely used graft material for spinal fusion, demineralized bone matrix preparations are available as alternatives or supplements to autograft. They are prepared by acid extraction of most of the mineralized component, with retention of the collagen and noncollagenous proteins, including growth factors. Differences in allograft processing methods among suppliers might yield products with different osteoinductive activities. The purpose of this study was to compare the efficacy of three different commercially available demineralized bone matrix products for inducing spinal fusion in an athymic rat model. METHODS: Sixty male athymic rats underwent spinal fusion and were divided into three groups of eighteen animals each. Group I received Grafton Putty; Group II, DBX Putty; and Group III, AlloMatrix Injectable Putty. A control group of six animals (Group IV) underwent decortication alone. Six animals from each of the three experimental groups were killed at each of three intervals (two, four, and eight weeks), and the six animals from the control group were killed at eight weeks. At each of the time-points, radiographic and histologic analysis and manual testing of the explanted spines were performed. RESULTS: The spines in Group I demonstrated higher rates of radiographically evident fusion at eight weeks than did the spines in Group III or Group IV (p < 0.05). Manual testing of the spines at four weeks revealed variable fusion rates (five of six in Group I, two of six in Group II, and none of six in Group III). At eight weeks, all six spines in Group I, three of the six in Group II, and no spine in Group III or IV had fused. Histologic analysis of the spines in Groups I, II, and III demonstrated varying amounts of residual demineralized bone matrix and new bone formation. Group-I spines demonstrated the most new bone formation. CONCLUSIONS: This study demonstrated differences in the osteoinductive potentials of commercially available demineralized bone matrices in this animal model.