Evaluation of 3D Printed Burr Hole Simulation Models Using 8 Different Materials.

OBJECTIVE: 3D printing is increasingly used to fabricate three-dimensional neurosurgical simulation models, making training more accessible and economical. 3D printing includes various technologies with different capabilities for reproducing human anatomy. This study evaluated different materials across a broad range of 3D printing technologies to identify the combination that most precisely represents the parietal region of the skull for burr hole simulation. METHODS: Eight different materials (polyethylene terephthalate glycol, Tough PLA, FibreTuff, White Resin, BoneSTN, SkullSTN, polymide [PA12], glass-filled polyamide [PA12-GF]) across 4 different 3D printing processes (fused filament fabrication, stereolithography, material jetting, selective laser sintering) were produced as skull samples that fit into a larger head model derived from computed tomography imaging. Five neurosurgeons conducted burr holes on each sample while blinded to the details of manufacturing method and cost. Qualities of mechanical drilling, visual appearance, skull exterior, and skull interior (i.e., diploë) and overall opinion were documented, and a final ranking activity was performed along with a semistructured interview. RESULTS: The study found that 3D printed polyethylene terephthalate glycol (using fused filament fabrication) and White Resin (using stereolithography) were the best models to replicate the skull, surpassing advanced multimaterial samples from a Stratasys J750 Digital Anatomy Printer. The interior (e.g., infill) and exterior structures strongly influenced the overall ranking of samples. All neurosurgeons agreed that practical simulation with 3D printed models can play a vital role in neurosurgical training. CONCLUSIONS: The study findings reveal that widely accessible desktop 3D printers and materials can play a valuable role in neurosurgical training.

Properties and Implementation of 3-Dimensionally Printed Models in Spine Surgery: A Mixed-Methods Review With Meta-Analysis.

OBJECTIVE: Spine surgery addresses a wide range of spinal pathologies. Potential applications of 3-dimensional (3D) printed in spine surgery are broad, encompassing education, planning, and simulation. The objective of this study was to explore how 3D-printed spine models are implemented in spine surgery and their clinical applications. METHODS: Methods were combined to create a scoping review with meta-analyses. PubMed, EMBASE, the Cochrane Library, and Scopus databases were searched from 2011 to 7 September 2021. Results were screened independently by 2 reviewers. Studies utilizing 3D-printed spine models in spine surgery were included. Articles describing drill guides, implants, or nonoriginal research were excluded. Data were extracted according to reporting guidelines in relation to study information, use of model, 3D printer and printing material, design features of the model, and clinical use/patient-related outcomes. Meta-analyses were performed using random-effects models. RESULTS: Forty articles were included in the review, 3 of which were included in the meta-analysis. Primary use of the spine models included preoperative planning, education, and simulation. Six printing technologies were utilized. A range of substrates were used to recreate the spine and regional pathology. Models used for preoperative and intraoperative planning showed reductions in key surgical performance indicators. Generally, feedback for the tactility, utility, and education use of models was favorable. CONCLUSIONS: Replicating realistic spine models for operative planning, education, and training is invaluable in a subspeciality where mistakes can have devastating repercussions. Future study should evaluate the cost-effectiveness and the impact spine models have of spine surgery outcomes.

'Burr holes in the bush': Clinician preparedness for undertaking emergency intracranial haematoma evacuation surgery in rural and regional Queensland.

OBJECTIVES: Delayed inter-hospital transfers of deteriorating neurotrauma patients from rural and regional hospitals to tertiary centres have seen the need for non-neurosurgeons to undertake emergency intracranial haematoma evacuation surgery locally. In the present study, the authors contributed to the paucity in the literature regarding the widespread availability of cranial access equipment in non-tertiary centres and patient outcomes in Queensland. METHODS: We surveyed delegates (senior theatre nurses or surgical service directors) from rural and regional Queensland hospitals if they were located outside the local catchment of a tertiary centre and had a CT scanner. Questions regarded availability, location and storage conditions of mechanical cranial access kits, as well as last usage, and associated patient outcomes. RESULTS: Twenty-six delegates from eligible hospitals responded. Eighteen hospitals offered surgical services. Eleven hospitals housed complete mechanical cranial access kits. Five hospitals housed incomplete kits. Thirteen hospitals housed their equipment sterile in the operating theatre or ED. Eleven hospitals reported using the equipment, with last usage ranging from 4 months to over 30 years. Two hospitals reported using the equipment within 12 months while a further five reported using it within 10 years. Two hospitals reported 'good' outcomes, two 'ok' and one 'poor'. CONCLUSIONS: The availability of cranial access equipment outside Queensland tertiary centres has been limited. Inter-hospital transfers are likely to persist in Queensland and haematoma evacuation surgery has been a life-saving endeavour, so improving access to cranial access equipment in hospitals where it is currently lacking is highly warranted.

A Medical-Grade Polycaprolactone and Tricalcium Phosphate Scaffold System With Corticoperiosteal Tissue Transfer for the Reconstruction of Acquired Calvarial Defects in Adults: Protocol for a Single-Arm Feasibility Trial.

BACKGROUND: Large skull defects present a reconstructive challenge. Conventional cranioplasty options include autologous bone grafts, vascularized bone, metals, synthetic ceramics, and polymers. Autologous options are affected by resorption and residual contour deformities. Synthetic materials may be customized via digital planning and 3D printing, but they all carry a risk of implant exposure, failure, and infection, which increases when the defect is large. These complications can be a threat to life. Without reconstruction, patients with cranial defects may experience headaches and stigmatization. The protection of the brain necessitates lifelong helmet use, which is also stigmatizing. OBJECTIVE: Our clinical trial will formally study a hybridized technique's capacity to reconstruct large calvarial defects. METHODS: A hybridized technique that draws on the benefits of autologous and synthetic materials has been developed by the research team. This involves wrapping a biodegradable, ultrastructured, 3D-printed scaffold made of medical-grade polycaprolactone and tricalcium phosphate in a vascularized, autotransplanted periosteum to exploit the capacity of vascularized periostea to regenerate bone. In vitro, the scaffold system supports cell attachment, migration, and proliferation with slow but sustained degradation to permit host tissue regeneration and the replacement of the scaffold. The in vivo compatibility of this scaffold system is robust-the base material has been used clinically as a resorbable suture material for decades. The importance of scaffold vascularization, which is inextricably linked to bone regeneration, is underappreciated. A variety of methods have been described to address this, including scaffold prelamination and axial vascularization via arteriovenous loops and autotransplanted flaps. However, none of these directly promote bone regeneration. RESULTS: We expect to have results before the end of 2023. As of December 2020, we have enrolled 3 participants for the study. CONCLUSIONS: The regenerative matching axial vascularization technique may be an alternative method of reconstruction for large calvarial defects. It involves performing a vascularized free tissue transfer and using a bioresorbable, 3D-printed scaffold to promote and support bone regeneration (termed the regenerative matching axial vascularization technique). This technique may be used to reconstruct skull bone defects that were previously thought to be unreconstructable, reduce the risk of implant-related complications, and achieve consistent outcomes in cranioplasty. This must now be tested in prospective clinical trials. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12620001171909; https://tinyurl.com/4rakccb3. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/36111.

Emergent craniotomy in rural and regional settings: recommendations from a tertiary neurosurgery unit: diagnosis and surgical decision-making.

Largely attributed to the tyranny of distance, timely transfer of patients with major traumatic brain injuries (TBI) from rural or regional hospitals to metropolitan trauma centres is not always feasible. This has warranted emergent craniotomies to be undertaken by non-neurosurgeons at their local hospitals with previous acceptable results reported in regional Australia. Our institution endorses this ongoing potentially life-saving practice when necessary and emphasize the need for neurosurgical units to provide ongoing TBI education to peripheral hospitals. In this first of a two-part narrative review, the authors describe the recommended diagnostic pathway for patients with a suspected TBI presenting to rural or regional hospitals and discuss local surgical management options in the presence or absence of a CT scanner.

Emergent craniotomy in rural and regional settings - recommendations from a tertiary neurosurgery unit: surgical technique and future prospects.

Kenneth G Jamieson described the emergent craniotomy for traumatic brain injuries (TBI) in the rural and regional setting back in 1965 in his book 'A First Notebook Of Head Injury'. Since then, there has been successful use of the technique in peripheral hospitals prior to the safe transfer of patients to metropolitan trauma centres. Although the procedure can be daunting in inexperienced hands, our institution supports ongoing education to continue implementation of trauma craniotomies by non-neurosurgeons if it means another life is potentially saved. Here we describe the surgical technique for an emergent craniotomy and craniectomy. Although the surgical technique has been described elsewhere, we have done so in a simplified 10-step approach with consideration of available resources in the peripheral hospital setting and the added pearls from the experience of a metropolitan neurosurgical unit. We also discuss future prospects for undertaking neurosurgical operations in peripheral hospitals but with intra-operative tele-surgery monitoring and supervision.

Intracranial infected collections and epidemiology in the top end, Northern Territory, Australia. A 10-year case series.

BACKGROUND: The incidence of intracranial infected collections (IIC) ranges between 0.4 and 1.2/100 000 persons per year. There is anecdotal evidence that residents in Top End of the Northern Territory are at a greater risk of infections with protracted clinical presentations. To our knowledge, there is no study to date to explore IIC in the Top End. METHODS: Retrospective observational analysis of IIC in the Top End, Northern Territory, Australia from 2009 to 2019. International classification of disease code G06 was used to identify cases diagnosed at Royal Darwin, Gove District and Katherine Hospital with no restriction of age or gender. RESULTS: A total of 51 cases were identified. This equated to an incidence of 2.9 (95% CI 2.2-3.8) in 100 000 PPY. When separated into Indigenous and non-Indigenous populations, the respective incidences were 8.65 (95% CI 6.2-12.1) and 1.1 (95% CI 0.7-1.9) in 100 000 PPY. The Indigenous population was at a significantly higher risk of IIC compared with non-Indigenous Australians with a relative risk of 7.3 (P < 0.0001 95% CI 4.0-13.3). The most common aetiology was otogenic infections with all cases being identified in the Indigenous population. Comparison of other clinical parameters between the two populations were not statistically significant. CONCLUSIONS: Within the limitations of a retrospective study, the incidence of IICs is higher in the Top End than reported elsewhere in the literature. This is particularly true for the Indigenous population.

Properties and Characteristics of Three-Dimensional Printed Head Models Used in Simulation of Neurosurgical Procedures: A Scoping Review.

BACKGROUND: Intracranial surgery can be complex and high risk. Safety, ethical and financial factors make training in the area challenging. Head model 3-dimensional (3D) printing is a realistic training alternative to patient and traditional means of cadaver and animal model simulation. OBJECTIVE: To describe important factors relating to the 3D printing of human head models and how such models perform as simulators. METHODS: Searches were performed in PubMed, the Cochrane Library, Scopus, and Web of Science. Articles were screened independently by 3 reviewers using Covidence software. Data items were collected under 5 categories: study information; printers and processes; head model specifics; simulation and evaluations; and costs and production times. RESULTS: Forty articles published over the last 10 years were included in the review. A range of printers, printing methods, and substrates were used to create head models and tissue types. Complexity of the models ranged from sections of single tissue type (e.g., bone) to high-fidelity integration of multiple tissue types. Some models incorporated disease (e.g., tumors and aneurysms) and artificial physiology (e.g., pulsatile circulation). Aneurysm clipping, bone drilling, craniotomy, endonasal surgery, and tumor resection were the most commonly practiced procedures. Evaluations completed by those using the models were generally favorable. CONCLUSIONS: The findings of this review indicate that those who practice surgery and surgical techniques on 3D-printed head models deem them to be valuable assets in cranial surgery training. Understanding how surgical simulation on such models affects surgical performance and patient outcomes, and considering cost-effectiveness, are important future research endeavors.

Pilot-administered anaesthesia and the Royal Flying Doctor Service of Australia: An interview with Captain Keith Galloway.

The lack of radio navigational aids in early Royal Flying Doctor Service aircraft in Australia occasionally resulted in aircraft being stranded at a remote site with a critically injured patient due to weather and other conditions. For a brief period in the 1950s, at least one Royal Flying Doctor Service pilot was trained to administer anaesthesia to critically ill patients who could not be immediately evacuated. The aim of this paper is to describe the circumstances in which this arose and how it worked in practice. This is based largely on the recollections of pilot anaesthetist Captain Keith Galloway, who shared his recollections during interviews with the authors.

Preparing for PrEP; the cost of delaying universal access in England.

OBJECTIVES: Pre-exposure prophylaxis (PrEP) is not commissioned within National Health Service (NHS) England. Individuals can access it privately online or by enrolment into a clinical trial. We established a list of individuals not enrolled in trials, awaiting PrEP. In response to the observation that patients awaiting PrEP trials were being referred with newly diagnosed HIV, we aimed to measure attendance, incident HIV, STI acquisition and missed opportunities for prevention. METHODS: The search was conducted for patients on the list from November 2017 to November 2019. We examined the electronic clinical records of those on the list and extracted demographic information, STI and HIV diagnoses. In addition, for those diagnosed with HIV, we reviewed risk factors including chemsex and prior postexposure prophylaxis. RESULTS: There were 1073 patients on list, and 520 (48.6%) were still awaiting recruitment in a PrEP trial. Eight (0.75%) had an enrolment appointment booked while 200 (18.64%) had been contacted and deemed ineligible according to PrEP trial criteria. 45 (32.15%) had not responded to contact. We identified 15 new HIV infections in patients awaiting PrEP. Of these, 9/15 (60.00%) did not meet eligibility criteria at point of contact, though had been eligible at first referral. CONCLUSION: It is unacceptable that 15 patients acquired HIV while waiting. The individual lifetime cost of treating HIV is estimated at £360 800(1). This equals £5 412 000 for these 15 infections notwithstanding the psychological and physical burden. We advocate the immediate role out of universal PrEP for those who need it on the NHS. While this decision is delayed, harm is coming to those waiting. Wider provision of PrEP may encourage increased attendance, but must consider additional resources to accommodate added visits. We are relieved that at the point of final submission (21 March 2020) NHS England have recently announced funding of PrEP for eligible patients from, further details are pending.

Septic arthritis of the lumbar facet joint. Case and literature review.

Septic Arthritis of the facet joint (SAFJ) is an uncommon but severe condition of the spine with only 61 cases published to date. Diagnosis is notoriously difficult and can take several months which can lead to significant delays in treatment. We report a case of a 52-year-old female with 2-month history of back pain diagnosed with septic arthritis of the left lumbar L4/5 facet joint and associated epidural abscess. She presented with no fevers, normal neurological examination and normal blood parameters posing a diagnostic challenge. In this report we conclude normal inflammatory markers cannot be used as exclusion criteria for the disease. We also review the body of literature to summarise the key features of the condition to assist clinicians in its diagnosis.

Check the Ear. The Importance of Ear Examinations in Assessment of Intracranial Subdural Empyema.

Intracranial subdural empyema (ISE) is an uncommon condition previously associated with almost 100% morbidity and mortality. Since the introduction of antibiotics and advancements in diagnosis the complication rates have significantly improved. We report an unusual case of a 32-year-old Aboriginal male diagnosed with ISE. On closer inspection the ISE was found to be a complication of otitis media with a cotton bud lodged in the external acoustic meatus. The report provides a literature review on the relationships of ISE, otitis media and foreign bodies. We conclude that although rare, all patients with suspected ISE should undergo an ear examination as it is at no cost to the patient or health service but may be the difference between life and death.

Non missile penetrating spinal injury.

Non-missile penetrating spinal injury (NMPSI) is a rare form of traumatic spinal injury. Cases with neurological deficit on presentation are treated surgically. In the extremely rare circumstance of NMPSI presenting with no neurological deficit the management is contentious. We report a case of a 43-year-old male presenting with a penetrating stab injury through the thoracolumbar spinal canal. On presentation he had no neurological deficits and subsequently the knife was removed in theatre without deep surgical exploration. In this report we review the literature of non-missile penetrating spinal injuries as well as their management and conclude that exploratory surgery for NMPSI without neurological deficit may not be necessary as previously thought.

Spontaneous cerebrospinal fluid rhinorrhoea and aspiration pneumonitis following initiation of continuous positive airway pressure treatment for obstructive sleep apnoea.

Continuous positive airway pressure (CPAP) therapy is very often the treatment of choice for obstructive sleep apnoea (OSA). The association between intracranial hypertension and spontaneous cerebrospinal fluid (CSF) rhinorrhoea is being increasingly recognized among patients with OSA. However, spontaneous CSF rhinorrhoea following initiation of CPAP therapy for OSA is very rarely documented in the literature. In this report, we describe a 53-year-old woman with severe OSA who, while being evaluated for possible intracranial hypertension, developed spontaneous CSF rhinorrhoea and CSF aspiration pneumonitis as a complication of CPAP therapy. Magnetic resonance imaging confirmed fluid tracks at the skull base, and a nasal swab demonstrated positive ß2-transferrin. Computer tomography (CT) chest showed findings consistent with CSF aspiration pneumonitis. Resolution of both CSF leak and pneumonitis were noted following treatment with azetozolamide and curative endoscopic trans-nasal surgery along with ventriculoperitoneal shunt.

Neurological injuries from skateboards in paediatric and adolescent populations: injury types and severity.

BACKGROUND: Skateboarding is a popular recreation among children and adolescents. Injuries that result in presentation to emergency departments are varied including head injuries. The study aims to assess the type and severity of neurological damage to the brain and spine in children from injuries incurred while using a skateboard. METHODS: After obtaining Ethics approval, a retrospective case review was performed of all admissions to all Brisbane, Australia public hospital neurosurgery departments of children 18 years and less who experienced injuries to the brain and spine for the years 2010-2014. RESULTS: There were 51 skateboard-related admissions over the study period of which 94% were male. The mean age was 14.3 years. The Injury Severity Score (ISS) ranged from 1 to 38 with a mean of 11.4. A total of 70.5% of the ISS scores fell within the minor or moderate categories and 29.5% fell within the serious and severe categories. There were no ISS scores in the critical category. A total of 16 skull vault fractures and 14 skull base fractures were recorded. There were 13 extradural haematomas of which five were evacuated by craniotomy and one of whom experienced hemiplegia. There was a spinal cord injury with paraplegia. A range of other neurological complications occurred. There were no deaths. CONCLUSION: Uncommon but serious neurological morbidity accompanies skateboard use. Concerns remain about the level of helmet use and choice of unsafe locations for skateboarding.

Intracranial Management of Perineural Spread in the Trigeminal Nerve.

Since the mid-1960s surgeons have attempted to cure intracranial perineural spread (PNS) of cutaneous malignancies. Untreated patients with trigeminal PNS die from brainstem invasion and leptomeningeal disease. It was understood that resection with clear margins was potentially curative, but early surgical attempts were unsuccessful. The prevailing wisdom considered that this surgery failed to improve the results achieved with radiation therapy alone and was associated with high morbidity. However, with improved imaging, surgical equipment, and better understanding of cavernous sinus (CS) anatomy and access, contemporary surgeons can improve outcomes for this disease. The aim of this paper is to describe a technique to access the interdural compartment of the CS and treat PNS of cutaneous squamous cell carcinoma (cSCC) in the intracranial trigeminal nerve and ganglion. It is based on the experience of the Queensland Skull Base Unit, Australia in managing PNS of cutaneous squamous cell carcinoma of the head and neck (cSCCHN).

Outcomes after surgery and postoperative radiotherapy for perineural spread of head and neck cutaneous squamous cell carcinoma.

BACKGROUND: Queensland, Australia, has the highest rates of cutaneous squamous cell carcinoma (SCC). Perineural invasion (PNI) is associated with reduced local control and survival. METHODS: A retrospective review of a prospective database of patients with clinical PNI from cutaneous SCC of the head and neck (SCCHN) treated with surgery and postoperative radiotherapy (PORT) between 2000 and 2011 and a minimum of 24 months follow-up. Patients were excluded if immunosuppressed, had non-SCC histology, or were treated palliatively. RESULTS: Fifty patients (mean age, 60 years) with median follow-up of 50 months were included in this study. A total of 54.8% of known primary tumors had incidental PNI. Ten percent had nodal disease at presentation. MRI neurogram was positive in 95.8%. Recurrence-free survival (RFS) at 5-years was 62%. Five-year disease-specific survival (DSS) and overall survival (OS) were 75% and 64%, respectively. There were no perioperative deaths. CONCLUSION: This report demonstrates that long-term survival is achievable in patients with clinical PNI from cutaneous SCCHN after surgery and PORT. © 2015 Wiley Periodicals, Inc. Head Neck 38: 824-831, 2016.

Surgical resection for clinical perineural invasion from cutaneous squamous cell carcinoma of the head and neck.

BACKGROUND: Perineural invasion (PNI) in cutaneous squamous cell carcinoma of the head and neck (SCCHN) is associated with decreased survival. Patients with large nerve or clinical PNI present with clinical signs and symptoms or MRI evidence of cranial nerve involvement. These patients often succumb to disease that spreads into the brainstem. In our experience, when the disease extends up to the Gasserian or Geniculate ganglion, surgical resection with negative margins provides the best chance for cure. Herein we review our experience to validate our clinical observations. METHODS: We identified patients with large nerve PNI from cutaneous SCCHN between January 1996 and 2006 from a prospectively collected database. Patients who underwent surgical resection as their primary mode of therapy were included. Clinical and demographic variables were recorded. Survival analysis was performed with Kaplan-Meier curves, and the log-rank test was used for significance testing between groups. RESULTS: Twenty-one patients were identified. The mean age was 60 (range, 38-86) years, with 15 men and 6 women. Nineteen patients had a formal skull base resection, whereas 2 patients had a subcranial resection. We had 3 complications in our series: extradural hemorrhage (n = 1), cerebrospinal fluid leak (n = 1), and wound infection (n = 1). None of the patients who underwent a formal skull base resection to include the lateral cavernous sinus (ie, Gasserian ganglion) suffered ocular palsies or permanent morbidity when the orbit was preserved (n = 11). We had no surgical deaths. The average length of stay was 9 days (SD 6.3 days). The 5-year disease specific survival rate for the entire group was 64.3%. V3 involvement resulted in lower, although not significant, 5-year disease-free survival rates- 0% for those patients with involvement (n = 4) versus 66.8% for no involvement of V3 (n = 17). CONCLUSION: Appropriately planned surgical resection of PNI in cutaneous SCCHN up to the ganglion as dictated by the disease extent may improve survival without significant added morbidity.