Hydroxyapatite Bone Research Articles

Minimal invasive horizontal ridge augmentation with Calcium Sulfate bone cement: A case series

Background: The objective of this retrospective study is to assess the minimal invasive technique for augmenting horizontal ridge or bone defects using biphasic calcium sulfate with hydroxyapatite bone cement. Methods: This study focused on 14 partially edentulous patients: 5 males and 9 females, aged between 36 and 82 years old. These patients were non-smokers and had no chronic diseases or received radiation treatment in the last 6 months. During their initial consultation, all patients underwent cone beam computed tomography. Horizontal bone augmentation was necessary for all patients to facilitate prosthetically driven implant surgery. Bond Apatite bone cement horizontal grafting was used for all patients, along with immediate or delayed implants (with or without immediate loading). One year after the final prosthetic placement, all cases were evaluated. The clinical progression of peri-implant volume and tissue quality was documented photographically, along with exams conducted every 6 months. The complete follow-up timeline for these cases ranged from 1 to 5 years. Results: A total of 34 implants were placed in the grafted zones, distributed among 14 patients. None of the patients reported any abnormal discomfort or swelling after surgery, and there were no infections or significant post-surgery complications noted. One year after the placement of various fixed prosthetic rehabilitations, all 100% of the implants remained stable with healthy peri-implant soft tissue and very satisfactory aesthetic results. Conclusion: The Bond Apatite bone cement has demonstrated exceptional effectiveness in reconstructing or augmenting horizontal defects and narrow ridges, increasing the available bone/soft tissue volume and soft enabling successful placement of implants, whether immediate or delayed, with or without immediate loading. Furthermore, the use of Bond Apatite resulted in minimal post-operative complications and an impressively low rate of postoperative infections, allowing for minimally invasive augmentation surgery, eliminating the need for extensive surgical flaps and free tension flap sutures typically associated with this type of procedure.

Freeze-Casted Keratin Matrix as an Organic Binder to Integrate Hydroxyapatite and BMP2 for Enhanced Cranial Bone Regeneration.

An ideal bone regenerative scaffold is expected to possess architectural characteristics that mimic the bone tissue, osteoconductive properties, and osteoinductive functionality. Key challenges to creating a scaffold with these ideal characteristics simultaneously are the selection of appropriate processing methods and biocompatible materials. Herein, human hair keratin is proposed as an organic binder for the simultaneous incorporation of bone's major inorganic component, hydroxyapatite and bone's growth factor, recombinant human bone morphogenetic protein 2 (rhBMP2) to enable both osteoconductive and osteoinductive characteristics in the creation of bone scaffolds. Furthermore, a freeze-casting method is selected to fabricate this rhBMP2-incorporated keratin/hydroxyapatite (KHA) scaffold with aligned lamellar pores to guide and promote bone regeneration. The aligned KHA scaffolds display better mechanical properties, sustained rhBMP2 release, good cell compliance, and 3D cellular infiltration. Implantation of KHA scaffolds in vivo reveals that scaffolds with aligned pores effectively accelerate the healing process of bone defects compared to scaffolds with random pores. This work indicates the distinctive potential of freeze-casted rhBMP-2 incorporated KHA scaffolds for bone regeneration.

Development of osteon-like scaffold-cell construct by quadruple coaxial extrusion-based 3D bioprinting of nanocomposite hydrogel

Despite advances in bone tissue engineering, fabricating a scaffold which can be used as an implant for large bone defects remains challenge. One of the great importance in fabricating a biomimetic bone implant is considering the possibility of the integration of the structure and function of implants with hierarchical structure of bone. Herein, we propose a method to mimic the structural unit of compact bone, osteon, with spatial pattern of human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (hMSCs) in the adjacent layers that mimic Haversian canal and lamella, respectively. To this end, coaxial extrusion-based bioprinting technique via a customized quadruple-layer core-shell nozzle was employed. 3D implant scaffold-cell construct was fabricated by using polyethylene glycol as a hollowing agent in the first layer, gelatin methacryloyl (GelMA) and alginate blended hydrogel encapsulating HUVEC cells with vascular endothelial growth factor nanoparticles in the second layer (vasculogenic layer) to mimic vascular vessel, and GelMA and alginate blended hydrogel containing hMSCs cells in the outer osteogenic layer to imitate lamella. Two types of bone minerals, whitlockite and hydroxyapatite, were incorporated in osteogenic layer to induce osteoblastic differentiation and enhance mechanical properties (the young's modules of nanocomposite increased from 35 kPa to 80 kPa). In-vitro evaluations demonstrated high cell viability (94 % within 10 days) and proliferation. Furthermore, ALP enzyme activity increased considerably within 2 weeks and mineralized extra cellular matrix considerably produced within 3 weeks. Also, a significant increase in osteogenic markers was observed indicating the presence of differentiated osteoblast cells. Therefore, the work indicates the potential of single step 3D bioprinting process to fabricate biomimetic osteons to use as bone grafts for regeneration.

Structural, Spectroscopic, and Biological Characterization of Novel Rubidium(I) and Europium(III) Co-Doped Nano-Hydroxyapatite Materials and Their Potential Use in Regenerative Medicine.

This research investigates hydrothermally synthesized hydroxyapatite nanoparticles doped with rubidium(I) and europium(III) ions. Investigation focused on establishing the influence of co-doped Eu3+ and Rb+ ions on hydroxyapatite lattice. Therefore, structural, and morphological properties were characterized via using X-ray powder diffraction (XRPD), infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM), as well as transmission electron microscopy (TEM) techniques. Furthermore, this investigation evaluates the impact of various Rb+ ion doping concentrations on the distinct red emission of co-doped Eu3+ ions. Hence, luminescence properties of the obtained materials were evaluated by measuring emission excitation, emission spectra, and luminescence decays. As established by numerous studies, synthetic hydroxyapatite has excellent application in biomedical field, as it is fully biocompatible. Its biocompatible makes it highly useful in the biomedical field as a bone fracture filler or hydroxyapatite coated dental implant. By the incorporation of Eu3+ ions and Rb+ ions we established the impact these co-doped ions have on the biocompatibility of hydroxyapatite powders. Therefore, biocompatibility toward a ram's red blood cells was evaluated to exclude potential cytotoxic features of the synthesized compounds. Additionally, experimental in vitro bioactive properties of hydroxyapatite nanoparticles doped with Rb+ and Eu3+ ions were established using a mouse osteoblast model. These properties are discussed in detail as they contribute to a novel method in regenerative medicine.

Assessment of tricalcium phosphate/titanium dioxide (TCP/TiO2) nanocomposite scaffold compared with bone autograft and hydroxyapatite (HA) on the healing of segmental femur bone defect in rabbits

Bone healing is a tissue process after a surgical operation. Many formulated materials have been designed for improving these procedures. The purpose of this study was to evaluate the effectiveness of nanocomposite tricalcium phosphate scaffolds combined with Titanium dioxide scaffold (TCP/TiO2) for femoral defects regeneration in rabbits. We studied 80 mature male New Zealand white rabbits weighing between 3 and 3.5 kg. Rabbits were subdivided into four groups. Anesthesia was performed before surgical operation by 50 mg/kg Ketamine 10% and 5 mg/kg xylazine 5% intramuscularly. We inducted a 6 × 5 mm diameter cylinder defect on the femur. Animals were separated into four trial groups of 20 animals each. After defecting, the experimental groups include control, autograft, hydroxyapatite, and TCP/TiO2 (received pure nanocomposite TCP/TiO2 material). A pathologist evaluated the sections on days 15, 30, 45, and 60 after surgery. The improvement of new and lamellar bone formation was the best in the nanocomposite TCP/TiO2 group at various point times, especially 60 days after surgery. We found that TCP/TiO2 nanocomposite has a significant improving function in the remodeling of bone in the defect areas.Graphical abstract

Study of hydroxyapatite in bones and in laser-deposited films for biomedical applications

Hydroxyapatite (HAp) present in bones has been studied and characterized using different physical analyses. Optical and scanning electron microscopies (SEM), Energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), attenuated total reflectance (ATR) – Fourier transform infrared (FTIR) spectroscopy have been employed. Particular attention has been given to the sample preparation as well to the lyophilization processes of bones, which can be employed for different applications. Pulse laser irradiation has been employed to deposit biocompatible thin HAp films in vacuum on Ti substrates. The prepared biocompatible substrates, which can be employed for metallic load prostheses, have been compared with the bone surface.

Fabrication of bioresorbable hydroxyapatite bone grafts through the setting reaction of calcium phosphate cement.

We prepared hydroxyapatite (HAp) bone grafts by the setting reaction of calcium phosphate cement, and investigated the effects of the porosity and crystallinity on the osteoconductivity and bioresorbability. We examined the effect of the water-mixing ratio, pressure, and post-heat treatment temperature during preparation on the crystallite size and porosity of the HAp blocks. The quantity of protein adsorption increased with increasing porosity and specific surface area (SSA) of the HAp blocks, whereas the initial cell attachment was similar despite the different porosities and crystallinities. In in vitro dissolution tests with a pH 5.5 buffer, which mimics an osteoclast-created Howship's lacuna, both the porosity and SSA of the HAp blocks affected the solubility; most likely due to the increased contact area with the buffer. Thus, HAp blocks prepared by the setting reaction of calcium phosphate cement could be applicable for bioresorbable HAp bone grafts because of the high porosity and SSA.

Ceramic bone graft substitute (Mg-HA) in spinal fusion: A prospective pilot study.

Background: Iliac crest bone graft (ICBG) is considered the gold standard for spine surgical procedures to achieve a successful fusion due to its known osteoinductive and osteoconductive properties. However, complications related to harvesting procedure and donor site morbidity have been largely reported in the literature, favoring the development of a wide range of alternative products to be used as bone graft extenders or substitutes for spine fusion. Among all, ceramic-based biomaterials have been widely studied and employed in the last years as bone graft substitutes. Methods: We report here the results of a prospective pilot study aimed to evaluating the grade of ossification obtained by the use of an Mg-doped hydroxyapatite (HA) product to achieve postero-lateral fusion in degenerative spine diseases. Results: Results show a successful degree of fusion of about 62% at the 12-month follow-up and an improvement of quality of life and health status following surgery, as evaluated by clinical scores (ODI, VAS, and EQ-5L). No adverse events related to the material were reported. Conclusion: The present pilot study shows the effectiveness and the safety profile of an Mg-doped HA bone graft substitute used to achieve postero-lateral fusion in the treatment of degenerative spine diseases, laying down the basis for further larger clinical investigations.

Marine plankton exoskeleton-derived honeycombed hydroxyapatite bone granule for bone tissue engineering

The recovery of biocompatible implantable biomaterials from biowaste is a significant method for protecting both human health and the environment concerns. This study aimed to evaluate the possibility of using hydroxyapatite (HAp) granules derived from planktonic exoskeleton bone in the ocean (OceanBone-HAp) as a bone graft substitute. The morphology and physiochemical properties of the OceanBone-HAp were evaluated using SEM, XRD and FT-IR. In addition, the absence of heavy metals and abundance of trace elements in OceanBone-HAp was confirmed using ICP-OES analysis. Moreover, in vitro results showed that OceanBone-HAp improved cell proliferation, adhesion, differentiation, and infiltration, compared to stoichiometric synthetic HAp granules (pure HAp). Additionally, OceanBone-HAp improved the expression of osteogenic related markers, by upregulation of ALP, collagen type-1αI(Col1αI), osteocalcin (OCN), and bone sialoprotein (BSP), which was confirmed using quantitative real-time polymerase chain reaction. Furthermore, in vivo bone regeneration was also evaluated using a rabbit calvarial defect model, and the results showed that the area of mature bone formation was significantly higher for OceanBone-HAp than pure HAp. These results demonstrated that OceanBone-HAp granules have good potential for use in bone healing as a bone graft material.

Comparative Evaluation of Hydroxyapatite Bone Alloplast with Combination Bone Alloplast (Hydroxyapatitie and ?-Tricalcium Phosphate) in Grade II Mandibular Furcation Involvements.

The management of furcation involvements by regenerative surgery with bone alloplast have been used with varying degrees of success in periodontal therapy. The aim of the study was to clinically and radiographically compare the effectiveness of Hydroxyapatite bone alloplast with combination bone alloplast (Hydroxyapatite and ?-Tricalcium phosphate) for the treatment of Grade II mandibular furcation involvements. Thirty patients with bilateral Grade II mandibular furcation involvements were distributed in Group A (Hydroxyapatite) and Group B (Hydroxyapatite and ?-Tricalcium phosphate). Clinical parameters such as Plaque Index, Gingival Index, Probing Pocket Depth, Clinical Attachment Level and Horizontal Probing Depth were recorded at baseline and at one, three and six mths postoperatively. Radiographic bone fill measurements were recorded at baseline and six months post-operatively. Both the groups showed statistically significant (p <0.01) improvement in clinical and radiographic parameters at each recall visits. Inter-group comparison of clinical parameters showed no significant difference in both the groups whereas radiographic measurements following six months post-surgery showed significantly (p <0.05) greater amount of bone fill in Group B compared to Group A. It can be concluded that at six months post-operative, both the alloplastic materials resulted in significant improvement in clinical parameters and no significant difference was found between both groups. There was a statistically significant radiographic bone fill when a combination of Hydroxyapatite and ?-Tricalcium phosphate was used demontrating its effectiveness in the treatment of Grade II Furcation involvement.

Three-Dimensional Printed Hydroxyapatite Bone Substitutes Designed by a Novel Periodic Minimal Surface Algorithm Are Highly Osteoconductive.

Autologous bone remains the gold standard bone substitute in clinical practice. Therefore, the microarchitecture of newly developed synthetic bone substitutes, which reflects the spatial distribution of materials in the scaffold, aims to recapitulate the natural bone microarchitecture. However, the natural bone microarchitecture is optimized to obtain a mechanically stable, lightweight structure adapted to the biomechanical loading situation. In the context of synthetic bone substitutes, the application of a Triply Periodic Minimum Surface (TPMS) algorithm can yield stable lightweight microarchitectures that, despite their demanding architectural complexity, can be produced by additive manufacturing. In this study, we applied the TPMS derivative Adaptive Density Minimal Surfaces (ADMS) algorithm to produce scaffolds from hydroxyapatite (HA) using a lithography-based layer-by-layer methodology and compared them with an established highly osteoconductive lattice microarchitecture. We characterized them for compression strength, osteoconductivity, and bone regeneration. The in vivo results, based on a rabbit calvaria defect model, showed that bony ingrowth into ADMS constructs as a measure of osteoconduction depended on minimal constriction as it limited the maximum apparent pore diameter in these scaffolds to 1.53 mm. Osteoconduction decreased significantly at a diameter of 1.76 mm. The most suitable ADMS microarchitecture was as osteoconductive as a highly osteoconductive orthogonal lattice microarchitecture in noncritical- and critical-size calvarial defects. However, the compression strength and microarchitectural integrity in vivo were significantly higher for scaffolds with their microarchitecture based on the ADMS algorithm when compared with high-connectivity lattice microarchitectures. Therefore, bone substitutes with high osteoconductivity can be designed with the advantages of the ADMS-based microarchitectures. As TPMS and ADMS microarchitectures are true lightweight structures optimized for high mechanical stability with a minimal amount of material, such microarchitectures appear most suitable for bone substitutes used in clinical settings to treat bone defects in weight-bearing and non-weight-bearing sites.

Repetitive Exposure of Titanium Mesh after Cranioplasty: A Case Report

Cranial defects are often managed with cranioplasty, where synthetic substances are still extensively used despite the advantages of using biological materials. Among the complications of cranioplasty, skin defects with implant exposure are the most common, with a particularly high incidence when titanium mesh is used. This is a case report of a 32-year-old patient who underwent cranioplasty with titanium mesh. After 2 years, a forehead skin defect with mesh exposure occurred, onto which a latissimus dorsi free flap was applied without removing the mesh. Ten months later, the patient was consulted for another skin defect, and a second latissimus dorsi free flap was applied with near-total mesh removal. After 6 months, another cranioplasty with hydroxyapatite bone cement and flap modification was performed. Lastly, revision surgery with complete removal of the mesh remaining in the right eyebrow was executed after 1 year, and no major complications were seen during the 4 months of follow-up. Through this experience, we suggest that skin defects with mesh exposure need to be managed with total removal of the metal material, followed by cranioplasty using another material and appropriate soft tissue coverage over the reconstructed cranium.

A STUDY TO EVALUATE THE HEARING EFFICACY OF BONE CEMENT OSSICULOPLASTY FOR INCUDOSTAPEDIAL REBRIDGING

Background:The goal of surgery in cases with chronic otitis media both safe and unsafe types is to achieve a maximal disease clearance and restore the near normal hearing. Various techniques of ossiculoplasty have been used to reconstruct the eroded ossicular chain. The ideal material to be employed in ossiculoplasty techniques should be bio active, bio compatible, safe, stable and with easier to apply. Hydroxyapatite, which is a calcium phosphate compound bone cement is similar in composition to living human bone and satisfies all the all above characteristics of an ideal ossiculoplasty material. Objectives:The purpose of this study is to evaluate the hearing outcomes of hydroxyapatite bone cement ossiculoplasty done in patients with incudostapedial erosion in both safe and unsafe types of chronic otitis media. The study is also aimed to determine the ideal candidates for bone cement ossiculoplasty. Methodology:A total of thirty patients of chronic otitis media with incudostapedial erosion were included in the study. Patients underwent ossicular reconstruction with hydroxyapatite bone cement. Preoperative and post operative hearing results with pure tone audiogram and impedance audiometry were recorded. One year period of follow up was done and reduction in air bone gap was analyzed. Results:The post operative air bone gap was found to be significantly reduced after a period of follow up of one year. The mean preoperative and postoperative pure tone averages was found to be 47.46 and 36.86 respectively. The mean preoperative and post operative air bone gaps were 37.89 and 27.28 respectively with p&lt;0.001. No complications were recorded during the study in relation to the bone cement. Conclusions:Incudostapedialrebridgingossiculoplasty with hydroxyapatite bone cement is a safe and reliable method that is cost effective and provides significant hearing outcomes in selected patients with no complications recorded.

Thermoluminescence response of bone hydroxyapatite

This study is an attempt to utilize hydroxyapatite of chicken bone in thermoluminescence (TL) dosimetry of beta rays. Bone samples were prepared with different molarities NaOH (0.5, 1, 2, 4) and etched in H2O2 at different intervals. The treated bones were characterized using X-ray diffraction (XRD) and Fourier Transform Infra-Red (FTIR) spectroscopy. The samples were irradiated by β-source to different doses. The thermoluminescence (TL) glow curves were obtained and analyzed using new TL software and the computerized glow curve (CGCD). The analyses revealed that each of the obtained curves is composed of eight overlapping peaks. All samples exhibited linear response with the applied doses. The results proved that natural hydroxyapatite can be considered as a promising candidate for TL dosimetry with simple treatment.

The fracture mechanical behavior simulation of calcium-deficient hydroxyapatite crystals by molecular dynamics and first-principles calculation

Natural hydroxyapatite provides certain strength and stiffness to biological bones, and most of the studies on the strength of bone tissues have been carried out on hydroxyapatite (HAP). However, the Ca/P ratio of hydroxyapatite in bones is actually about 1.50, and the natural hydroxyapatite belongs to calcium-deficient hydroxyapatite (CDHA) with Ca vacancy defects. Therefore, this work focused on the effect of Ca vacancy defects on CDHA crystals through investigating the generation and expansion of microcracks under uniaxial tensile loading by combining molecular dynamics and first principles method. A series of crystal models with different Ca vacancy ratios are constructed and find that Ca vacancies degrade the mechanical properties of hydroxyapatite. Meanwhile the fracture behavior of crystals is detailed and find that the cracks arise at vacancies and extend along the direction of vacancies. Also, first-principles calculation is performed to reveal the mechanism of crack formation in MD simulations. It is found that the decrease of Ca–O bonding of CDHA causes the decrease of the stability of the crystal structure by analyzing the DOS of HAP and CDHA, and the cracks originate from Ca vacancies. This work performs more realistic simulations of CDHA with calcium vacancy defects in actual bone tissue and directly reveals the development and progression of bone fragility at the nanometer scale.

Additive manufacturing of graphene oxide/hydroxyapatite bioceramic scaffolds with reinforced osteoinductivity based on digital light processing technology

In the field of bone tissue engineering, porous hydroxyapatite (HA) bone repair scaffolds with controlled architecture and porosity are challenging to manufacture and lack sufficient osteoinductive activity, which limit its wider clinical application. This study fabricated porous graphene oxide (GO)/HA composite ceramic scaffolds using digital light processing (DLP) technology. The properties of the composite ceramic slurry and the process parameters of curing, degreasing, and sintering were initially examined to ensure molding accuracy. The research showed that a small amount of GO (0.1–0.4 wt%) could better maintain the pore structure and improve the mechanical properties of composite ceramics. Porous scaffolds with pore sizes of 300–400 μm were prepared for co-culture with rat bone marrow mesenchymal stem cells to detect biocompatibility. The results showed that all scaffolds have no cytotoxicity. Compared with HA, the GO/HA ceramic scaffold significantly promoted the cell adhesion, proliferation, and expression of osteogenesis-related genes; GO (0.1–0.2 wt%) /HA scaffolds exhibited superior alkaline phosphatase activity and more effective bone mineralization, showing enhanced osteoinductivity. The porous GO/HA composite scaffold fabricated by DLP presented a strong potential for repairing bone defects.

Research progress of bone-targeted drug delivery system on metastatic bone tumors.

Bone metastases are common in malignant tumors and the effect of conventional treatment is limited. How to effectively inhibit tumor bone metastasis and deliver the drug to the bone has become an urgent issue to be solved. While bone targeting drug delivery systems have obvious advantages in the treatment of bone tumors. The research on bone-targeted anti-tumor therapy has made significant progress in recent years. We introduced the related tumor pathways of bone metastases. The tumor microenvironment plays an important role in metastatic bone tumors. We introduce a drug-loading systems based on different environment-responsive nanocomposites for anti-tumor and anti-metastatic research. According to the process of bone metastases and the structure of bone tissue, we summarized the information on bone-targeting molecules. Bisphosphate has become the first choice of bone-targeted drug delivery carrier because of its affinity with hydroxyapatite in bone. Therefore, we sought to summarize the bone-targeting molecule of bisphosphate to identify the modification effect on bone-targeting. And this paper discusses the relationship between bisphosphate bone targeting molecular structure and drug delivery carriers, to provide some new ideas for the research and development of bone-targeting drug delivery carriers. Targeted therapy will make a more outstanding contribution to the treatment of tumors.

Ra-223 induces clustered DNA damage and inhibits cell survival in several prostate cancer cell lines

The bone-seeking radiopharmaceutical Xofigo (Radium-223 dichloride) has demonstrated both extended survival and palliative effects in treatment of bone metastases in prostate cancer. The alpha-particle emitter Ra-223, targets regions undergoing active bone remodeling and strongly binds to bone hydroxyapatite (HAp). However, the toxicity mechanism and properties of Ra-223 binding to hydroxyapatite are not fully understood. By exposing 2D and 3D (spheroid) prostate cancer cell models to free and HAp-bound Ra-223 we here studied cell toxicity, apoptosis and formation and repair of DNA double-strand breaks (DSBs). The rapid binding with a high affinity of Ra-223 to bone-like HAp structures was evident (KD= 19.2 × 10−18 M) and almost no dissociation was detected within 24 h. Importantly, there was no significant uptake of Ra-223 in cells. The Ra-223 alpha-particle decay produced track-like distributions of the DNA damage response proteins 53BP1 and ɣH2AX induced high amounts of clustered DSBs in prostate cancer cells and activated DSB repair through non-homologous end-joining (NHEJ). Ra-223 inhibited growth of prostate cancer cells, independent of cell type, and induced high levels of apoptosis. In summary, we suggest the high cell killing efficacy of the Ra-223 was attributed to the clustered DNA damaged sites induced by α-particles.

The effect of alpha-lithium aluminate incorporation on the properties of bovine bone-derived hydroxyapatite

The effect of alpha-lithium aluminate incorporation on the properties of bovine bone-derived hydroxyapatite

Postmastoidectomy Hyperacusis Syndrome: Clinical Features and Treatment.

We report a novel postmastoidectomy hyperacusis syndrome (PMHS) in patients who have had cortical mastoidectomies and experience hyperacusis to stimuli involving touch of the pinna and periauricular area. This report aims to describe the clinical characteristics of patients predisposed to this disabling complication after mastoid surgery and describes surgical treatment with mastoid cortex resurfacing with hydroxyapatite bone cement. Three patients who have undergone intact canal wall mastoidectomies for nonchronic middle ear-related pathologies all reported a similar constellation of postoperative symptoms. None of the patients had any ossicular chain or middle ear abnormalities, and none had preoperative conductive hearing loss. All patients reported disabling hyperacusis related to light touch stimuli in the periauricular area. On examination, all three patients demonstrated synchronous movement of the tympanic membrane when the postauricular area was palpated. After a period of observation, none of the patients noted any improvement to their symptoms. Resurfacing of the mastoid cortex with hydroxyapatite bone cement was performed in all patients. Presence of touch-induced hyperacusis and audiometry was assessed postoperatively. Patients were also examined for synchronous movement of the tympanic membrane with palpation of the postauricular area. All patients experienced complete resolution of touch-induced hyperacusis postoperatively. Pure-tone audiometric hearing thresholds remained unchanged after mastoid cortex resurfacing, and there was no longer tympanic membrane movement with palpation of the postauricular area. PMHS can occur in patients after cortical mastoidectomy when there is no history of ossicular chain or history of chronic middle ear disease or middle ear abnormalities. PMHS can cause significant distress to patients and remain underrecognized unless synchronous tympanic membrane movement is specifically examined for. Treatment via mastoid cortex surfacing with hydroxyapatite bone cement is safe and effective.