The periosteal microcirculation in health and disease: An update on clinical significance

Distraction osteogenesis in combined sequential use of external fixation and nailing (lengthening and then nailing): An experimental study in rabbits

Limb lengthening relies on the process of distraction osteogenesis. The active periosteal bone formation has been detected in clinical practice with a lengthening and then nail (LATN) technique but has not been confirmed by experimental studies to date. The aim of this study is to compare the tissue regeneration of the distraction regenerate during tibial lengthening in rabbits using a LATN technique. This study was performed on 54 mature rabbits of the Soviet Chinchilla breed, which were divided into three groups of 18 animals. In group 1 (control), the tibia was lengthened in an external fixator. In group 2, the LATN technique was modeled and in group 3, lengthening over nail (LON) was modeled. The total duration of the experiment was 45 days. On the 10th, 15th, 20th, 30th, and 45th day X-ray, computed tomography and morphological studies were performed. In the experimental groups (2 and 3), a more pronounced periosteal bone formation in the area of regenerate was noted when compared to group 1. In group 2 (LATN), wide cortical plates were formed from the intermediate and periosteal areas. In this group, the maximum densitometric density values were noted. Endosteal bone formation was preserved in all groups. The LON and LATN techniques, when compared with the classical Ilizarov lengthening, do not demonstrate any deficiency in the tissue regeneration of the bone tissue at the regenerate sites. The most powerful bone structures are formed with the sequential use of the external fixation and nailing (LATN).

Alendronate reduces periosteal microperfusion in vivo

Objectives

Bisphosphonates are known to induce a severe adverse effect known as medication-related osteonecrosis of the jaw (MRONJ). Previous studies have proven the impact of bisphosphonates on microperfusion; therefore, this study aimed to investigate alendronate-induced microcirculatory reactions in the calvarial periosteum of rats.

Study design

Bone chambers were implanted into 48 Lewis rats. Microhemodynamics, inflammatory parameters, functional capillary density and defect healing were examined after alendronate treatment for two and six weeks using repetitive intravital fluorescence microscopy for two weeks.

Results

Microhemodynamics remained unchanged. In alendronate-treated rats, inflammation was slightly increased, functional capillary density was significantly reduced (day 10: controls 100.45 ± 5.38 cm/cm2, two weeks alendronate treatment 44.77 ± 3.55 cm/cm2, six weeks alendronate treatment 27.54 ± 2.23 cm/cm2) and defect healing was decelerated. The changes in functional capillary density and defect healing were dose-dependent.

Conclusion

The bisphosphonate alendronate has a significant negative impact on periosteal microperfusion in vivo. This could be a promising target for the treatment of MRONJ.

Mesenchymal stem cells prevent ovariectomy-induced osteoporosis formation in mice through intraosseous vascular remodeling

Mesenchymal stem cells (MSCs) can promote osteogenesis and are a promising therapy for postmenopausal osteoporosis. However, the relationship between improved intraosseous microcirculation and increased bone mass induced by MSCs in postmenopausal osteoporosis remains unclear. After the primary MSCs were characterized, they were transplanted into ovariectomized mice. MSCs transplantation enhanced the trabecular number, trabecular bone volume/total volume, and trabecular bone mineral density in ovariectomized mice. To determine the role of MSCs in vascular repair, mice were subjected to femoral artery ligation. Through laser speckle flowmetry, vascular perfusion and femoral trabecular bone and cortical bone analyses, we determined the effects of MSCs in promoting intraosseous angiogenesis and preventing osteoporosis in mice. MSCs effectively prevented postmenopausal osteoporosis development, which is associated with the involvement of MSCs in reestablishment of microcirculation within the skeleton.

Pretreatment Systemic Immune-Inflammation Index Predict Needs for Teeth Extractions for Locally Advanced Head and Neck Cancer Patients Undergoing Concurrent Chemoradiotherapy

Background

To evaluate the utility of pretreatment systemic immune-inflammation index (SII) in predicting the teeth caries and need for tooth extraction after concurrent chemoradiotherapy (C-CRT) for locally advanced squamous-cell head and neck cancer (LA-SCHNC) patients.

Methods

The records of LA-SCHNC patients who underwent formal dental evaluations at pre- and post-C-CRT periods were retrospectively analyzed. The pretreatment SII values were calculated using the platelet, neutrophil, and lymphocyte measures acquired on the first day of C-CRT: SII=Platelets×neutrophils/lymphocytes. Receiver operating characteristic (ROC) curve analysis was employed to identify the ideal pre-C-CRT SII cutoff that may predict the teeth caries and the need for tooth extraction after the C-CRT. The primary endpoint was the link between the pre-C-CRT SII and the need for tooth extraction during the follow-up period.

Results

A sum of 126 patients were included. Median follow-up was 4.9 years (range: 2.7–7.8). Nasopharyngeal and laryngeal cancers comprised the majority (75.4%) study cohort. Post-treatment teeth extractions were reported in 62.7% patients. The optimal cutoff was 558 [Area under the curve (AUC): %76.8 sensitivity: 72.3%; and specificity: 70.9%] that grouped the patients into two subgroups with significantly different post-C-CRT tooth extraction rates: Group 1: SII≤558 (n = 70) and SII>558 (n = 56), respectively. Correlation analysis revealed a significant relationship between the pretreatment SII and the tooth extraction rates after the C-CRT (r_s:0.89: P = 0.001). The comparative analysis displayed that the teeth extractions rates were significantly higher in the SII>558 group (77.1% versus 51.4% for SII≤558; Hazard ratio: 1.68; P = 0.001). Further analyses showed that the pre-C-CRT SII>558 was the unique factor associated with meaningfully higher necessities for post-C-CRT teeth extractions.

Conclusion

The present outcomes intimated that high pretreatment SII levels were linked to significantly increased post-treatment teeth extractions in LA-SCHNC patients undergoing definitive C-CRT.

Impaired Callus Formation in Pathological Mandibular Fractures in Medication-Related Osteonecrosis of the Jaw and Osteoradionecrosis

PURPOSE

Nonsurgical treatment of mandibular fractures secondary to medication-related osteonecrosis of the jaw (MRONJ) or osteoradionecrosis (ORN) mostly results in nonunion, whereas nonsurgical fracture treatment of atrophic fractures can achieve favorable results in selected cases. The aim of this study was to compare callus formation in pathological mandibular fractures due to MRONJ, ORN, or extreme mandibular atrophy.

METHODS

A retrospective cohort study reviewing the medical records of all MRONJ-, ORN-, or atrophy-related fractures treated at the departments of maxillofacial surgery in the Leuven or Lille university hospitals between 2010 and 2019 was undertaken. The primary predictor variable in this study was disease state (MRONJ, ORN, or extreme mandibular atrophy). The primary outcome variable was callus formation after 1 month of follow-up (present, absent). Additional study variables measured included patient age and gender. T-tests, Fisher exact tests, and multiple logistic regression were used for statistical analysis. The significance level was set at P < .05.

RESULTS

Seventy patients were analyzed (12 MRONJ cases, 54 ORN fractures, 4 atrophic fractures). The callus formation prevalence in nonsurgically approached fractures secondary to ORN and MRONJ after 1 month of follow-up was 3.03% (2/66 cases). In contrast, callus was detected in all patients in the mandibular atrophy-related fracture group. Osteonecrosis was statistically correlated with impaired callus formation (P = .0121).

CONCLUSION

Whereas one would expect indirect fracture healing and thus callus formation to occur in all non-surgically treated fractures, our data demonstrate its absence in the majority of MRONJ- and ORN-related fractures. Multiple plausible explanations for this phenomenon were identified: periosteal damage with loss of callus-forming cells, compromised vasculature, and bacterial colonization.

Complications of Poly-l-Lactic Acid and Polyglycolic Acid (PLLA/PGA) Osteosynthesis Systems for Maxillofacial Surgery: A Retrospective Clinical Investigation

Two second-generation PLLA/PGA bioresorbable osteosynthetic plate systems for oral and maxillofacial surgery are available in Japan. The two systems have different PLLA-PGA component ratios (RapidSorb^®, 85:15; Lactosorb^®, 82:18) and plate and screw shapes. We conducted a retrospective study to compare our clinical evaluation and examine the incidence of postoperative complications between the two plate systems. A retrospective survey was conducted in 148 patients (midfacial fracture/trauma (68.2%) and dentofacial deformity patients (31.8%); males (54.7%); median age, 37.5 years) treated using maxillofacial osteosynthetic plate systems. The complications included plate exposure (7.4%), infection, (2.7%), and plate breakage (0.7%). Multivariate logistic regression analysis showed a significant correlation between sex (female), plate system (Lactosorb^®), number of plates, and pyriform aperture and periorbital sites of plate placement (p < 0.05). Additionally, the propensity score-adjusted model showed a significant correlation between Lactosorb^® and postoperative complications (odds ratio 1.007 (95% confidence interval, 1.001–1.055), p < 0.01). However, the two plate systems showed a low incidence rate of complications, and the plate integration and survivability were similar using 2.0-mm or 1.5-mm resorbable plate regardless of the plate system. Our findings suggest that female sex and a greater number of plates are risk factors for postoperative complications, whereas pyriform aperture and periorbital plate placements reduce the risk.

Bone grafting history affects soft tissue healing following implant placement

BACKGROUND

This study aimed to determine and compare soft tissue healing outcomes following implant placement in grafted (GG) and non-grafted bone (NGG).

METHODS

Patients receiving single implant in a tooth-bound maxillary non-molar site were recruited. Clinical healing was documented. Volume and content of wound fluid (WF; at 3, 6, and 9 days) were compared with adjacent gingival crevicular fluid (GCF; at baseline, 1, and 4 months). Buccal flap blood perfusion recovery and changes in bone thickness were recorded. Linear mixed model regression analysis and generalized estimating equations with Bonferroni adjustments were conducted for repeated measures.

RESULTS

Twenty-five patients (49 ± 4 years; 13 males; nine NGG) completed the study. Soft tissue closure was slower in GG (P < 0.01). Differential response in WF/GCF protein concentrations was detected for ACTH (increased in GG only) and insulin, leptin, osteocalcin (decreased in NGG only) at day 6 (P ≤0.04), with no inter-group differences at any time(P > 0.05). Blood perfusion rate decreased immediately postoperatively (P < 0.01, GG) followed by 3-day hyperemia (P > 0.05 both groups). The recovery to baseline values was almost complete for NGG whereas GG stayed ischemic even at 4 months (P = 0.05). Buccal bone thickness changes were significant in GG sites (P ≤ 0.05).

CONCLUSION

History of bone grafting alters the clinical, physiological, and molecular healing response of overlying soft tissues after implant placement surgery.

Microcirculatory consequences of limb ischemia/reperfusion in ovariectomized rats treated with zoledronic acid

Background

Nitrogen-containing bisphosphonates (BIS) are potent therapeutics in osteoporosis, but their use may result in osteonecrotic side-effects in the maxillofacial region. Periosteal microcirculatory reactions may contribute to the development of bone-healing complications, particularly in osteoporotic bones, where ischemia–reperfusion (IR) events often develop during orthopaedic/trauma interventions. The effect of BIS on the inflammatory reactions of appendicular long bones has not yet been evaluated; thus, we aimed to examine the influence of chronic zoledronate (ZOL) administration on the periosteal microcirculatory consequences of hindlimb IR in osteopenic rats.

Materials and methods

Twelve-week-old female Sprague–Dawley rats were ovariectomized (OVX) or sham-operated, and ZOL (80 μg/kg iv, weekly) or a vehicle was administered for 8 weeks, 4 weeks after the operation. At the end of the pre-treatment protocols, 60-min limb ischemia was induced, followed by 180-min reperfusion. Leukocyte-endothelial interactions were quantitated in tibial periosteal postcapillary venules by intravital fluorescence videomicroscopy. CD11b expression of circulating polymorphonuclear leukocytes (PMN, flow cytometry) and plasma TNF-alpha levels (ELISA) were also determined. Two-way RM ANOVA followed by the Holm–Sidak and Dunn tests was used to assess differences within and between groups, respectively.

Results

Limb IR induced significant increases in PMN rolling and firm adhesion in sham-operated and OVX rats, which were exacerbated temporarily in the first 60 min of reperfusion by a ZOL treatment regimen. Postischemic TNF-alpha values showed a similar level of postischemic elevations in all groups, whereas CD11b expression only increased in rats not treated with ZOL.

Conclusions

The present data do not show substantial postischemic periosteal microcirculatory complications after chronic ZOL treatment either in sham-operated or OVX rats. The unaltered extent of limb IR-induced local periosteal microcirculatory reactions in the presence of reduced CD11b adhesion molecule expression on circulating PMNs, however, may be attributable to local endothelial injury/activation caused by ZOL.

Osseous Remodeling Around Dental Implants

Adequate bone remodeling may be a primary parameter for long-term successful complication-free dental implant treatment. A 1.8-mm osseous thickness around dental implants is thought to be the minimum thickness for adequate vasculature for osteocyte nutrition and function. A dental implant does not provide progenitor cells or angiogenic or osteogenic factors. Thus, the surrounding bone may need to have a 1.8-mm thickness to accommodate the vasculature necessary for nutrients for appropriate remodeling. Additionally, the 1.8-mm dimension may provide for mechanical load resistance. There is no evidence to illustrate the physiologic need for the 1.8-mm dimension. This dimension requirement is based on clinical outcome observations. Basic science research for bone survival around dental implants is needed.

Periosteal elevation induces supracortical peri-implant bone formation

PURPOSE

The aim of the study was to evaluate the possibility of supracortical peri-implant bone formation after periosteal elevation.

MATERIALS AND METHODS

Periosteal elevation with an elevation height of 5 or 10 mm was performed in an animal experiment with 24 female domestic pigs. For this purpose, four implants were inserted in the frontal bone of each animal. The implants protruded from the local bone by 5 or 10 mm. In the test groups, the periosteum was attached to the protruding implants. In the control groups, the implants were covered with biocompatible degradable periosteal-shielding devices. Each 8 animals were sacrificed after 20, 40 and 60 days. De novo bone formation was evaluated radiographically and histologically.

RESULTS

Bone formation rate was higher in the test groups compared to the control groups after 20, 40 and 60 days. After 40 and 60 days, a statistically significant higher (P < 0.01) bone formation rate was found for both elevation heights. The maximum height of the generated bone was statistically significantly higher (P < 0.01) in the test groups for both elevation heights, compared to the control groups for all time points investigated.

CONCLUSION

Periosteal elevation by dental implants is a treatment option for supracortical peri-implant bone formation.