Bone Removal Research Articles

A Preliminary Study on Animal Experiments of Robot-Assisted Craniotomy

Traditional craniotomy relies on the surgeon's experience and can be complicated owing to excessive skull bone removal, undesirable brain tissue penetration, or severe bleeding. For craniotomy, we developed a robot system based on intraoperative cone-beam computed tomography image guidance and human-robot cooperative interaction, aiming to improve the safety and accuracy of surgery and reduce the labor-intensiveness of the procedure. Intraoperative cone-beam computed tomography image guidance was adopt to improve the accuracy in our experiment. Craniotomy was performed using an interactive method based on human-robot collaboration, which could achieve a natural interactive method in accordance with surgeons' operating habits. The frequency-based method of contact distinction and the method of torque estimation were used to improve the safety of the designed robot. An animal experiment was conducted to verify the effectiveness of the robot system. During the drilling process, the position error was 0.92 ± 0.17 mm (upper surface) and 0.97 ± 0.11 mm (lower surface), and the angle error was 3.37 ± 1.43°. During the milling process, the position error was 1.06 ± 0.13 mm (upper surface) and 1.09 ± 0.09 mm (lower surface). The results showed that the system had sufficient precision and could better complete craniotomy with human-robot collaboration. In addition, with the feedback of multisensor information, the robot system could achieve a sufficient level of safety. The robot system can achieve accurate positioning and safe user-friendly human-robot interaction, which solves problems encountered in the drilling and milling of craniotomy, meets clinical needs, and provides a new method for robot-assisted craniotomy.

Narrowing of the remnant portal vein diameter and decreased portal vein angle are risk factors for portal vein thrombosis after perihilar cholangiocarcinoma surgery.

To evaluate the incidence, risk factors, management options, and outcomes of portal vein thrombosis following major hepatectomy for perihilar cholangiocarcinoma. A total of 177 perihilar cholangiocarcinoma patients who (1) underwent major hepatectomy and (2) underwent investigating the portal vein morphology, which was measured by rotating the reconstructed three-dimensional images after facilitating bone removal using Aquarius iNtuition workstation between 2002 and 2018, were included. Risk factors were evaluated using the Kaplan-Meier method and Cox proportional hazard models. Six patients developed portal vein thrombosis (3.4%) within a median time of 6.5 (range 0-22) days. Portal vein and hepatic artery resection were performed in 30% and 6% patients, respectively. A significant difference in the probability of the occurrence of portal vein thrombosis (PV) within 30 days was found among patients with portal vein resection, a postoperative portal vein angle < 100°, remnant portal vein diameter < 5.77 mm, main portal vein diameter > 13.4 mm, and blood loss (log-rank test, p = 0.003, p = 0.06, p < 0.0001, p = 0.01, and p = 0.03, respectively). Decreasing the portal vein angle and narrowing of the remnant PV diameter remained significant predictors on multivariate analysis (p = 0.027 and 0.002, respectively). Reoperation with thrombectomy was performed in four patients, and the other two patients were successfully treated with anticoagulants. All six patients subsequently recovered and were discharged between 25 and 70 days postoperatively. Narrowing of the remnant portal vein diameter and a decreased portal vein angle after major hepatectomy for perihilar cholangiocarcinoma are significant independent risk factors for postoperative portal vein thrombosis.

Robotic Resection of a Nerve Sheath Tumor Via a Retroperitoneal Approach.

Resection of large nerve sheath tumors in the lumbar spine using minimally invasive approaches is challenging, as approaches to tumors in this region may require facetectomy or partial resection of adjacent ribs for access to the involved neuroforamen and instrumentation across the involved joint to prevent subsequent kyphotic deformity. To describe a robot-assisted retroperitoneal approach for resection of a lumbar nerve sheath tumor, obviating the need for facetectomy and instrumentation. The operation is described, together with intraoperative images and an annotated video, in the context of a schwannoma arising from the right L1 root. The operation was performed by a urologic surgeon and a neurosurgeon. The patient was placed in lateral position, and the da Vinci Xi robot was used for retroperitoneal access via 5 ports along the right flank. Ultrasound was used to localize the tumor within the psoas. The tumor capsule was defined and released. Encountered nerves were stimulated, allowing small sensory nerves to be identified and safely divided. The tumor was traced into the right L1-L2 neuroforamen and removed. Complete en bloc resection of the tumor was achieved, including the paraspinal and foraminal components, without any removal of bone and without violation of the dura. In selected patients, a robot-assisted retroperitoneal approach represents a minimally invasive alternative to traditional approaches for resection of lumbar nerve sheath tumors. This approach obviates the need for bone removal and instrumented spinal fusion. Interdisciplinary collaboration, as well as use of adjunctive technologies, including intraoperative ultrasound and neurophysiologic monitoring, is advised.

Ultrasonic bone removal from the ossicular chain affects cochlear structure and function

IntroductionUltrasonic bone removal devices (UBD) are capable of cutting through bony tissue without injury to adjacent soft tissue. The feasibility and safety of using this technology for removal of bone from an intact ossicular chain (as might be required for otosclerosis or congenital fixation) was investigated in an animal model.MethodsThis was a prospective animal study conducted on seven anesthetised adult chinchillas. An UBD was used to remove bone from the malleus head in situ. Pre and post-operative distortion product otoacoustic emission (DPOAE) levels and auditory brainstem response (ABR) thresholds were recorded. Scanning electron microscopy (SEM) was used to assess cochlear haircell integrity.ResultsPrecise removal of a small quantity of bone from the malleus head was achieved by a 30s application of UBD without disruption of the ossicular chain or tympanic membrane. DPOAEs became undetectable after the intervention with signal-to-noise ratios (SNR) < 5 dB SPL in all ears. Furthermore, ABR thresholds were elevated > 85 dB SPL in 13 ears. SEM showed significant disruption of structural integrity of the organ of Corti, specifically loss and damage of outer haircells.ConclusionsAlthough UBD can be used to reshape an ossicle without middle ear injury, prolonged contact with the ossicular chain can cause structural and functional injury to the cochlea. Extensive cochlea pathology was found, but we did not investigate for recovery from any temporary threshold shift. In the authors’ opinion, further study should be undertaken before consideration is given to use of the device for release of ossicular fixation.Graphical abstract

Using Expandable Micro-Motor Bur (EMB) forExtraction of Molar Tooth Root of Dog's UpperJaw

Extraction of a broken tooth root is often a traumatic involvement for both the specialist and the patient. To extract broken roots, generally, invasive approaches as open window surgeries or mucoperiosteal flap and/or removal of buccal bone are performed. Expandable micro-motor bur (EMB) is a practical dental instrument proposed for the removal of broken teeth roots that cannot be extracted by the routine closed methods. The device comprises a micro-motor, spacers, needles, bur base, and a round bur that drills halfway through the root canal, expands to make a spherical cavity around itself, and behaves as an efficient extraction aiding anchor. The utilization of EMB would introduce a new technique in the removal of broken teeth roots in which surgical trauma is minimized and so are post-extraction disorders. The use of EMB would also eliminate surgical invasion to the surrounding tissues, and it would eliminate profound hand forces by the practitioner, consequently reduces stress for both the practitioner and the patient. It would also eliminate high-risk aftermaths of the surgery such as operative morbidity (due to bone loss), maxillary sinus exposure, and probable need for additional surgery which are some of the implications of the conventional open access approaches. We have tested the prototype of EMB on the molar tooth root of a dog in his upper jaw (M1) in the Medical Sciences and Technologies Research Institute of Shahid Beheshti University. No injuries to the buccal bone and surrounding nerves were observed and the root was successfully extracted. Further studies are needed to confirm its effectiveness in clinical cases.

Role of medial orbital wall decompression in COVID-19-associated rhino-orbital mucormycosis management

Dear Editor, The second wave of the COVID-19 pandemic has brought new challenges for ophthalmologists. There has been a surge in cases of rhino-orbital mucormycosis. When there is orbital involvement, proptosis is evident; in addition, there is chemosis, ptosis, limitation of ocular movements, and diminution of vision. Orbital inflammation with an increase in intra-orbital pressure is the primary cause for this. In addition, there is colonization of the orbital apex by the virulent fungus. Eventually, there is loss of vision either due to the inflammation or thrombosis of the arterial supply to the optic nerve. In our series of 111 cases of rhino-orbital mucormycosis, we performed an MRI scan or CT scan in all patients. All the patients were receiving intravenous liposomal amphotericin B, which is fungicidal. All cases underwent functional endoscopic sinus surgery (FESS) and at the time of completion of FESS, the nasal cavity and sinuses were thoroughly debrided and washed. When we noted signs of orbital inflammation or raised intra-orbital pressure, as judged by finger pressure comparing the two eyes or if there were clinical signs such as chemosis, ptosis, ocular movement limitation, or diminution of vision, we performed an endoscopic removal of the ethmoid bone completely, thus exposing the periorbita and made two cuts in the periorbita, above and below the medial rectus muscle anteroposteriorly and allowed orbital fat to prolapse into the sinuses. Thirty-six patients underwent this medial orbital wall decompression, and none needed orbital exenteration. Postoperatively, there was an improvement of the ptosis, and ocular movements, resolution of the chemosis, and vision was maintained or improved in all patients [Fig. 1]. Five patients had no light perception at presentation and vision did not improve in them. There was no recurrence at the 3-month follow-up. MRI scan shows enlarged extraocular muscles in most cases with pressure on the optic nerve and this surgical maneuver relieves this pressure. This surgical step is commonly performed in cases of thyroid eye disease where there are signs of inflammation and increased intra-orbital pressure.[12] We recommend performing this surgical procedure along with FESS as needed, as this is effective in preventing unsightly proptosis with loss of vision and thus obviates the need for exenteration.Figure 1: A 52-year- old lady, presented on the tenth day, post COVID-19 infection, with right eye pain, swelling and diplopia. She had chemosis, limited ocular movements, lid edema and proptosis. (a). Following medial orbital wall decompression with institution of intravenous Amphotericin B, the chemosis, diplopia and proptosis resolved, as seen in the 3-week postoperative picture (b). MRI scan (c) T2 coronal and (d) T1 axial scan shows sinusitis involving the ethmoid and maxillary sinuses at the time of presentationDeclaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Sandblasted, Acid Etched and UV Irradiated Titanium Surface for Dental Implants: In Vitro and in Vivo Analysis

In the implant dentistry field, rehabilitation through osseointegrated implants have been a huge advance, leading to excellent outcomes. Biomaterial integration to bone tissue determines the implant clinical success and the recovery of lost functionality, depending on clinical and engineering factors and patient whole health. Because of this, it is important the development of new strategies to achieve higher success rates and to decrease the healing period of osseointegrated implants. The present study addresses the UV irradiation effect on superficial characteristics of sandblasted and acid etched titanium discs. Furthermore, the irradiation protocol with the best outcomes was selected and applied to titanium implants placed in vivo in order to study the influence of the UV irradiation over the surrounding tissue. The results showed that UVC, but not UVA, enhanced surface hydrophilicity significantly. After 24 h of exposure to UVC, a superhydrophilic surface was obtained, with higher protein adsorption capability. New bone formation occurred for all the implants considered, with no detriment of bone density and removal torque for UVC irradiated group. Further studies are needed to assess whether this improved surface promotes the growth of bone tissue around the implant.

A Commentary on Craniotomy.

A craniotomy is a brain surgery, which involves the surgical removal of bone from the skull to expose the brain. The word craniotomy means making a hole (-otomy) in the skull (cranium).A craniotomy can be performed to remove brain tumors or blood clots and to repair skull fractures which are caused during a severe head injury. This surgery is also recommended in the treatment of epilepsy and Parkinson’s disease.Craniotomy is a critical operation performed by neurologists who specializes in surgical procedure of the brain and spine.

Two Cases of Bone Infection after Cranioplasty Treated with Minimum Skin Incision by Using Neuro-endoscope

Cranioplasty is usually performed in patients with previous external decompression for massive cerebral edema accompanied by severe brain hemorrhage or malignant infarction. However, post-operative infection sometimes occurs after the cranioplasty. If an infection occurs, infected bone removal and second cranioplasty is required. In such cases, the second cranioplasty is difficult because of the thin scar from the previous operation and skin atrophy. We report our experience of two cases requiring a third cranioplasty due to repeated cranial bone infections. In these two cases, we could successfully perform cranioplasty with minimum skin incision by peeling back the skin and dura mater using a neuro-endoscope.

Craniovertebral junction chordomas: Case series and strategies to overcome the surgical challenge.

Introduction:Chordomas are rare and malignant primary bone tumors. Different strategies have been proposed for chordomas involving the craniovertebral junction (CVJ) compared to other locations. The impossibility to achieve en bloc excision, the impact on stability and the need for proper reconstruction make their surgical management challenging.Objective:The objective is to discuss surgical strategies in CVJ chordomas operated in a single-center during a 7 years' experience (2013-2019).Methods:Adult patients with CVJ chordoma were retrospectively analyzed. The clinical, radiological, pathological, and surgical data were discussed.Results:A total number of 8 patients was included (among a total number of 32 patients suffering from skull base chordoma). Seven patients underwent endoscopic endonasal approach (EEA), and posterior instrumentation was needed in three cases. Three explicative cases were reported: EEA for midline tumor involving lower clivus and upper cervical spine (case 1), EEA and complemental posterior approach for occurred occipitocervical instability (case 2), C2 chordoma which required aggressive bone removal and consequent implant positioning, focusing on surgical planning (timing and type of surgical stages, materials and customization of fixation system) (case 3).Conclusion:EEA could represent a safe route to avoid injuries to neurovascular structure in clival locations, while a combined approach could be considered when tumor spreads laterally. Tumor involvement or surgical procedures could give raise to CVJ instability with the need of complementary posterior instrumentation. Thus, a tailored preoperative planning should play a key role, especially when aggressive bone removal and implant positioning are needed.

Feasibility of the Far Lateral Suboccipital Approach to the Retroodontoid Region. How Much Bone Removal Is Truly Needed?

ObjectiveThe posterolateral extradural suboccipital approach can be used to reach the anterior epidural space and the retro-odontoid regions. The extent of necessary bone removal of the atlas vertebra (C1) has not yet been defined. We studied the changes in the size of the horizontal and vertical surgical windows using stepwise bone removal of C1. A representative case is shown. MethodsThe anatomical study was performed bilaterally on five Thiel-fixed human cadavers (mean age, 83.7 years). The surgical window (horizontal × vertical) required to access the retro-odontoid region via a posterolateral approach was measured for an intact C1 posterior arch, after a semicircular inferior partial resection of the C1 arch, after resection of the unilateral hemiarch of C1, and finally after drilling approximately 3 mm from the medial aspect of the lateral mass of C1. ResultsThe intact C1 resulted in a very narrow surgical window of 6.3 mm × 9.7 mm (horizontal × vertical). The vertical window increased to a 13 mm after the semicircular inferior partial resection of the C1 arch and to 17.3 mm in the case of removal of the ipsilateral C1 posterior arch. The bone removal from the medial aspect of the C1 lateral mass resulted in a widening of the horizontal surgical window to 10.3 mm. The final size of the surgical window was 10.3 mm × 17.3 mm. The patient with severe kyphoscoliosis of the craniocervical spine was successfully operated on using odontoid and C1–2 facet osteotomies. ConclusionIf only the anterior epidural space or the base of the odontoid needs to be reached, the semicircular inferior partial resection of the C1 arch allows for an adequate surgical window. The tip of the odontoid could only be reached if the ipsilateral posterior arch is resected.

Early injection of autologous bone marrow concentrates decreases infection risk and improves healing of acute severe open tibial fractures

IntroductionOpen fractures are at risk of nonunion; surgeons are reluctant to propose early standard bone grafting after open fractures, preferring to wait in order to adequately assess the facture status of infection. Bone marrow contains mesenchymal stem cells (MSCs) and granulocyte and macrophage precursors identified in vitro as colony forming units-granulocyte macrophage (CFU-GM), both of which have a prophylactic action against infection. We therefore tested the hypothesis that early injection of bone marrow concentrate would be useful in these fractures. MethodsWe evaluated a series of 231 patients who had received early percutaneous implantation of bone marrow concentrate (BMC) to treat open fractures (with gap less than 10 mm) that were Gustilo-Anderson Type II or III. The results were compared with those of 67 control (no early graft) patients and with those of 76 patients treated with an early, standard of care, iliac bone graft. All patients were treated with external fixation and were considered to have an aseptic fracture at the time of early grafting, but the actual status of infection was re-assessed at the time of grafting by histology and/or analysis of the aspirate. The bone marrow graft contained after concentration 49,758 ± 21,642 CFU-GM-derived colonies/cc and 9400 ± 1435 MSCs/cc which represents an important increase compared to the level of CFU-GM cells and MSCs present in a standard auto-graft. Healing was evaluated at 9 months. ResultsThe rate of unsuspected infections was higher than 15% in the 3 groups. Bone union and removal of external fixation was achieved at 9 months by 50.7% of patients in the Control Group, by 86.8% of patients in the group with a standard bone graft, and by 87.4% of patients in the bone marrow group. A 90% risk reduction (p = 0.005) in the need for an invasive standard bone graft to treat a nonunion and in the risk of infection was observed when bone marrow was proposed as early injection to the treatment of type II or type-III tibial fractures. ConclusionBone marrow concentrate for early grafting in open fractures with limited gap was efficient for healing while decreasing infection.

Piezoelectric surgery versus conventional rotary surgical technique for surgical removal of impacted mandibular third molars: A prospective study

Introduction: Impacted third molar surgery is a frequently performed procedure in clinical work. Surgical removal of impacted third molars is often required in symptomatic conditions. Conventional rotary cutting instruments may be potentially injurious, so piezosurgery has been introduced as a new osteotomy technique with promising outcome. Purpose of this study was to compare techniques of surgical removal of impacted mandibular third molars using piezosurgery versus the conventional surgical technique. The parameters were time required, patient satisfaction, severity of pain and mouth opening postoperatively. Materials and Methods: This prospective study consisted of 20 medically fit patients between 18–40 years of age with bilateral impacted mandibular third molars from both the genders. On one side surgical extraction was done using conventional rotary technique and contra lateral side was treated using piezosurgery (split mouth study design). Statistical analysis was done between these two techniques for patient satisfaction, duration of surgery, pain perception and trismus. Results: Piezoelectric surgery took more time than rotary, but patient satisfaction, pain, mouth opening was statistically poor with conventional rotary technique. Conclusion: Piezoelectric device is a promising, meticulous, innovative ultrasonic technique for safe and effective bone removal when compared with rotary technique. Keywords: Piezoelectric surgery, Rotary surgical technique, Surgical removal, Mandibular impacted third molar.

Comparison of unilateral rostral, middle and caudal segmental mandibulectomies as an alternative treatment for unilateral temporomandibular joint ankylosis in cats: an ex vivo study.

Temporomandibular joint ankylosis (TMJA) is the partial or complete inability to open the mouth due to intra- or extra-articular fibrous, bony or fibro-osseous tissue proliferation. Surgical procedures such as gap arthroplasty, condylectomy or wide extra-articular osteotomy have been recommended to treat this condition; these techniques are challenging, time-consuming and have been occasionally associated with postoperative recurrence, severe periarticular neurovascular iatrogenic trauma and death. Segmental mandibulectomy had previously been recommended as an alternative option for unilateral TMJA, but the location of mandibulectomy and extent of bone removal from the mandible region have not been mentioned in the literature. This study aimed to validate the area of the mandibular body (rostral, middle or caudal) and amount of bony tissue that should be osteotomized during a segmental mandibulectomy for treatment of unilateral TMJA in cats. In this block study, 30 cadaver heads of domestic shorthair cats were randomly divided into three groups of 10 specimens each based on the mandibular region that would undergo segmental mandibulectomy (rostral, middle and caudal). The size of the removed mandibular segment and pre- and postoperative vertical range of mandibular motion were compared for statistical purposes. A significant statistical difference was observed between the pre- and postoperative vertical range of mandibular motion between the rostral, middle and caudal segmental mandibulectomies (P <0.001). The mean postoperative recovered range of mandibular motion for the rostral, middle and caudal segmental mandibulectomies was 50.4%, 81.9% and 90.4%, respectively. The caudal segmental mandibulectomy showed the highest postoperative vertical range of mandibular motion. The removal of a minimum of 1.2 cm of the caudal mandibular body was required to achieve nearly full recovery of presurgical mouth opening in the specimens of this study. The caudal segmental mandibulectomy may eliminate the risk of iatrogenic periarticular neurovascular damage inherent to more invasive surgeries performed at the temporomandibular joint area. When performed unilaterally, the caudal segmental mandibulectomy is a viable surgical alternative that may show a similar outcome to other surgical techniques.

Analysis of the Sonopet Ultrasonic Bone Aspirator to Traditional Instrumentation for Endoscopic Suturectomy for Craniosynostosis.

The goal of endoscopic treatment for craniosynostosis is to remove the fused suture and achieve calvarial remodeling with external orthosis. To reduce the need for secondary surgery and to minimize blood loss, instruments that maximize bone removal while minimizing blood loss and risk of dural injury are evolving. The authors therefore assess the safety and efficacy of the Sonopet Ultrasonic Bone Aspirator (UBA) (Stryker, Kalamazoo, MI) for endoscopic suturectomy compared to traditional instrumentation at our institution. Retrospective chart review of consecutive endoscopic suturectomies performed from 2011 to 2019 at Weill Cornell Medical Center was conducted, including demographics, cephalic index, surgical indications, operative time, cosmetic and functional results, complications, estimated blood loss (EBL), re-operation rate, length of stay, and length of helmet therapy. These variables were then compared between the Sonopet and non-Sonopet cohorts. Of the 60 patients who underwent endoscopic suturectomy, 16 cases (26.7%) utilized the Sonopet. Mean operative time was 2.8 ± 0.4 hours in the Sonopet group, compared to 3.2 ± 1.2 hours (P = 0.05) without the Sonopet. EBL was 17.8 ± 23.9 cc versus 34.7 ± 75.5 cc (P = 0.20) with versus without the Sonopet respectively. Length of stay and duration of helmet therapy were similar in both groups, ranging from 1 to 3 days (P = 0.68) and 7.25 to 12 months (P = 0.30) respectively. There were no reoperations in the Sonopet group with a mean follow up of 9.18 months. There were 3 reoperations in the non-Sonopet group with a mean follow up of 11.3 months. Among the cases utilizing the Sonopet, 13 (81%) were metopic and three (19%) were coronal synostoses. Of the non-Sonopet cases, 27 (61%) were sagittal, 8 (18%) were metopic, 7 (16%) were coronal, and 2 (5%) were lambdoid synostoses. The use of the Sonopet resulted in a mean decrease in operative time at our institution (P = 0.18). Lower EBL and reoperation rates with comparable LOS and helmet therapy duration were also seen. This modality should be considered a safe and effective adjunct in appropriate endoscopic craniosynostosis cases.

The associated benefits of a cranioplasty on rehabilitation: a review of the literature

Background: There is an ever-increasing demand for appropriate neurorehabilitation to optimise recovery post-traumatic brain injury. Some patients undergo decompressive surgery, which involves partial removal of the skull bone to help relieve the associated swelling and oedema. These patients are left with a skull defect and are placed on a waiting list for surgical repair of same by means of a procedure referred to as a cranioplasty. Cranioplasty, until recently, was not regarded as being a clinical priority in the neurorehabilitation phase, given the limited evidence supporting enhanced recovery. Aims: To highlight the phenomenon syndrome of the trephined and to establish the potential impact it has on enhanced neurorehabilitation and recovery. Methods: The paper is a narrative literature review of the associated effects of a cranioplasty on rehabilitation published in peer-reviewed journals between 2013 and 2019. Papers were identified via a search of PubMed, Medline and CINAHL electronic databases. Findings: The associated symptoms of syndrome of the trephined are predominately motor and cognitive in nature and are believed to result in a stalling or regression of the recovery process until the skull defect is repaired. The writer has critically analysed studies that have compared motor and cognitive functioning pre- and post-cranioplasty. Patients with enhanced functioning in the cognitive domain displayed marked improvements in the areas of memory, language and executive functioning. With regards to motor function, improvements were most evident in areas of activities of daily living, eating, grooming, walking and toileting. The theory underlying these improvements appears to be physiological in nature. Conclusions: Contrary to former opinion, the findings of this literature review highlight the importance of repairing skull breech prior to rehabilitation to optimise patient recovery for those experiencing syndrome of the trephined. The recommendations support the need for further research and education, as well as the development of a screening assessment tool that can be used by all members of the multidisciplinary team.

Clinical Evaluation of Decompressive Craniectomy in Malignant Middle Cerebral Artery Infarction using 3D Area and Volume Calculations.

Objective:We aimed to measure the craniectomy area using three-dimensional (3D) anatomic area and volume calculations to demonstrate that it can be an effective criterion for evaluating survival and functional outcomes of patients with malignant middle cerebral artery (MCA) infarction.Material and Methods:The patients diagnosed with malignant ischemic stroke between 2013 and 2018, for which they underwent surgery due to deterioration in their neurological function, were retrospectively reviewed. Radiological images of all patients were evaluated; total brain tissue volume, ischemic brain tissue volume, total calvarial bone area, and decompression bone area were measured using 3D anatomical area and volume calculations.Results:In total, 45 patients (27 males and 18 females) had been treated with decompressive craniectomy (DC). The removed bone area was found to be significantly related to the outcome in patients with MCA infarction. The average decompression bone area and mean bone removal rate for patients who died after DC were 112 ± 27 cm2 and 20%, whereas these values for surviving patients were 149 ± 29 cm2 and 26% (P = 0.001), respectively. At the 6-month follow-up, the average decompression bone area and mean bone removal rate for patients with severe disability were 126 ± 30 cm2 and 22.2%, whereas these values for patients without severe disability were 159 cm2 ± 26 and 28.4% (P = 0.001), respectively.Conclusion:In patients with malignant MCA infarction, the decompression area is associated with favorable functional outcomes, first, survival and second, 6-month modified Rankin scale score distribution after craniectomy.

A comparison of techniques for the explantation of osseointegrated dental implants

Data sources A search of electronic databases (Embase and PubMed) was carried out along with manual and grey searches of published and unpublished journals. Publication year was from first available until 23 August 2018.Study selection Titles and abstracts from the original search were reviewed by two authors. Studies were chosen for full-text analysis and data extraction after inter-reviewer agreement. Disagreement was resolved by discussion and Cohen's kappa was used to measure inter-reviewer agreement. An initial search gave 2,197 articles and, following screening, 18 publications were included in the study. Five articles were case series and ten were case reports describing one to nine cases. Three publications reported on comparatively large sample sizes, one prospectively and two retrospectively. None of the studies had control groups or blinding. The QUADAS-2 tool was used for quality assessment. Studies were deemed to have high, low or unclear levels of bias by two examiners. All were considered high risk of bias. Publications included fulfilled the following criteria: English language, human studies, endosseous osseointegrated dental implants, explantation technique described and reason for explantation clearly reported.Data extraction and synthesis Data extraction followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline process. Studies chosen for analysis were examined and the following data parameters were included: study design, number of patients, number of implants removed, implant system, reason for explantation, explantation technique and its success or failure, complications, flap access, socket grafting and immediate implant placement.Results The following five techniques for explantation of dental implants were identified: reverse torque, trephines, piezosurgery, burs and laser-assisted explantation. Reverse torque was the most commonly described technique (284 implants) with 87.7% success. Burs were used to remove 49 implants with 100% success, while trephines were used for explantation of 35 implants with 94% success. Piezosurgery and Er, Cr: YSGG laser removed 11 implants and one implant, respectively, with 100% success. One study reported perforation of the maxillary sinus floor following the use of a trephine technique, while another reported the fracture of three implants using reverse torque. The quality of the studies and lack of available data prevented further analysis. Results were presented in a narrative format.Conclusion The authors recommend reverse torque as the first choice for explantation. Despite its inferior success rate, it is the most conservative technique in terms of bone removal and flap access, meaning there is a greater opportunity for immediate implant placement.

A sequential regularization based image reconstruction method for limited-angle spectral CT

In spectral computed tomography (CT), the object is respectively scanned under different x-ray spectra. Multiple projection data can be collectively used for reconstructing basis images and virtual monochromatic images, which have been used in material decomposition, beam-hardening correction, bone removal, and so on. In practice, projection data may be obtained in a limited scanning angular range. Images reconstructed from limited-angle data by conventional spectral CT reconstruction methods will be deteriorated by limited-angle related artifacts and basis image decomposition errors. Motivated by observations of limited-angle spectral CT, we propose a sequential regularization-based limited-angle spectral CT reconstruction model and its numerical solver. Both simulated and real data experiments validate that our method is capable of suppressing artifacts, preserving edges and reducing decomposition errors.

Extended endonasal approaches for pituitary adenomas.

Pituitary adenomas with significant extension beyond the sellar boundary, large size, asymmetrical shape and subarachnoid space invasion, although rare, represent a therapeutic challenge. The invasiveness of the tumor itself often limits the potential for complete tumor resection and increases the likelihood of intraoperative or postoperative complications, regardless of the approach. The extended endoscopic endonasal approach has been proposed as a valid alternative to the transcranial route for the treatment of certain pituitary adenomas not suitable to the standard transsphenoidal approach. Thanks to the wide and close up view provided by the endoscope via the appropriate expanded bone removal at the skull base, this technique offers, in an adequate working space, a safe exposure of the tumor and surrounding anatomical structures, at the supra-, para-, and retro-sellar areas. It stands clear that the primary goal of this approach remains the maximum allowed resection with preservation of neurological and endocrine functions. Herein, we debate the extended endoscopic endonasal technique for the treatment of pituitary adenomas, with the aim of underlying its indications, pitfalls, advantages, and limitations.