DOI: 10.31038/SRR.2018113

Abstract

In recent years, Virtual Reality based platforms and technologies have come to play a key role in supporting training of medical residents and doctors in medicine including surgery. The focus of this paper is to discuss several platforms including haptic, Virtual Reality, Mixed Reality and distributed collaborative web based cyber training technologies. The design and role of these simulators in the context of two surgical procedures (LISS plating and Condylar plating surgery) is discussed for training application contexts. These surgical procedures are performed to treat the fractures of the femur bone. A comparison of these simulation technologies including emerging low cost platforms are discussed along with an overview of the impact of using such cyber based approaches on medical training.

Keywords

Virtual Reality (VR), Simulator, Haptic, Immersive, Cloud bases, Orthopedic surgery

Introduction

VR based surgical training environments have been developed for various surgical domains such as heart surgery [1, 2], laparoscopic surgery [3, 4] among others. There are a number of simulators available in the orthopedic surgery field; however, most of them have been built for arthroscopic surgical training. Only few researchers have focused on the design of VR based simulators for the complex fracture related surgical training [5, 6].  Orthopedic medical training is currently limited by use of traditional methods. Such methods involve training by observing an expert surgeon performing surgery, practicing on cadavers or animals, etc.

Developing VR based simulators for surgical training will help improve and supplement the traditional methods used to train the residents and medical students. There are several platforms and technologies available which can be used for creating VR based simulators for orthopedic surgical training. Each of the platforms have unique attributes which make them suitable for training residents in surgical training. In this paper, the focus is on the emerging as well as traditional platforms and technologies used in the creation of such simulators. The discussion is presented in the context of orthopedic surgical procedures including Condylar plating [7] and LISS (Less Invasive Stabilization System) plating surgery [8, 9]. Both these surgical procedures are performed by orthopedic surgeons to treat fractures of the femur bone. Four platforms and technologies discussed in this context are

• Haptic Platform
• Immersive Virtual Reality (VR) Platform
• Mixed Reality (MR) based Platform
• Distributed Web based Platform

Haptic based simulator platforms

Many researchers have created VR based simulators using haptic interfaces and technologies. For example, the design and validation of a bone drilling simulator was presented in [10]. In [11], a VR based simulator to improve the bone-sawing skills of residents using haptic designed and presented. Other researchers have utilized haptic technologies as well for arthroplasty, osteotomy and open reduction training in [12] and cardiac catheter navigation in [13].

Haptic based simulators built for training medical residents in LISS plating surgery and Condylar plating surgery has been demonstrated to improve understanding of these surgical procedures [7, 8, 14, 41, 42]. These simulators have been developed using Geomagic Touch™ haptic device which provides a haptic interface allowing users to touch, grasp and interact with various surgical tools during the training activities. An intuitive ‘feel’ for various tasks during the training activities is provided through the haptic interface. Such tasks include picking up various plates or tools, placing them accurately in a certain location, drilling the bone, screwing the bolts etc. The haptic device consists of a stylus which is used to interact with the virtual objects. The stylus has with two buttons. A resident can pick up an instrument or other virtual object by pressing and holding the dark colored button (figure 1). The pressing of the button allows user to make a virtual contact with the target object. The haptic simulator was built using the Unity 3D^TM simulation engine using C# and JavaScript. A haptic plugin was used to create support for the haptic based interface. The various virtual objects in the simulation environment such as bones, surgical implants such as Condylar plates and supports, were designed using Solidworks^TM.  A view of the haptic based LISS plating surgical environment has been shown in figure 2.

Figure 1. A haptic device used in surgical training

Figure 2. A view of one of LISS plating surgical training environments

Immersive VR (IVR) Simulator Platforms

Recently, immersive platforms such as Vive^TM and Oculus Rift^TM have been explored to design VR simulators for medical surgical training contexts [16–18]. These emerging platforms support immersive capabilities at a lower cost compared to traditional technologies such as the VR CAVE^TM and PowerWall^TM. In [18], a comparison between non-immersive and immersive Vive laparoscopic simulator has been presented. In [19], residents were tested on scenarios such as appropriate completion of primary survey, responding to vital cues from the monitor and recognizing fatal situations in a fully immersive VR blunt thoracic trauma simulator. Test and survey were conducted to assess the simulator and the results suggested that it can be used as a viable platform for training.

An innovative Immersive VR (IVR) simulator has been developed using the HTC Vive system for both LISS plating and Condylar plating surgical procedures [7]. This Vive based simulator system consists of a fully immersive headset, pair of wireless handheld controllers and two tracking cameras (figure 3). Cameras are used to track the position of the user in the virtual environment. The Vive headset has a field of view of 110˚ which increases the level of immersion allowing users to interact with the environment more naturally. The two wireless handheld controllers allow users to freely explore and interact with the virtual environment. In the context of LISS plating surgery (for example), users (or residents) can perform various surgical tasks such as assembly, screw insertion and tightening, drilling among others using the controllers. A view of a user interacting with the virtual environment wearing the Vive headset and using the controllers can be seen in figure 3. This IVR simulator was also developed using the Unity 3D game simulation engine C# and JavaScript were used to program the simulation environments. Steam VR toolkit and a third party VR toolkit were used to build this simulator. The major modules of the IVR simulator include a VR manager, Simulation Training manager and User Interface Manager. The Simulation Training manager coordinates all the interactions between the simulator and the users. The User Interface manager coordinates the input from the users and transmits it to the required training environment. The VR manager module serves as a bridge between Vive plugins and the Unity based simulation (graphical) environment. In figure 4, a view of the Condylar plate assembly environment for the IVR simulator is shown.

Figure 3. A user interacting with the IVR simulator

Figure 4. A view of Plate Insertion Training Environment (one of the six training environments developed for IVR condylar plating simulator)

Mixed Reality based Platforms

The Mixed Reality (MR) platform typically allows users to interact with both the real and virtual worlds at the same time; the primary advantage of such an MR platform is that a user can be guided by a simulation scenario to practice specific surgical steps using components in a physical environment; this allows a more integrated training scenario where residents and budding surgeons can practice various steps in a procedure with appropriate guidance from the virtual environment (running on the MR headset). A MR based simulator has been built using the Microsoft HoloLens^TM platform and the Unity 3D engine [7, 31] to support training activities in both LISS plating and Condylar plating procedures and developed using the Unity 3D engine. The HoloLens is an untethered and portable MR based device in which user can interact with the virtual environment immersively without losing the sense of the real world environment. In the context of surgical training, the user can interact with virtual surgical objects using the finger based gesture supported by HoloLens and practice the same steps with corresponding physical surgical instruments, plates and other components. A programming toolkit known as the Windows 10 SDK was used during the building of the simulator. A user can be seen interacting with the HoloLens using the finger gesture in the figure 5. In figure 6, a view of the user assembling the LISS plating components using finger gestures can be seen.

Figure 5. A medical resident interacting with the HoloLens using finger gestures

Figure 6. A view of one of the HoloLens’ based training scenarios (to assemble the LISS plate)

Distributed/Web based Platforms

Information centric approaches have gained prominence recently due to the emergence of smart technologies that support web based interactions. However, the need to create such information centric approaches has been underscored by earlier research in manufacturing and engineering; one of the earliest initiatives involved creating an information centric function model to understand the complexities of designing fixtures for use in computer aided manufacturing contexts [33]; other more recent efforts have focused on creating information centric process models to understand the complexities of surgical activities prior to designing and building simulation based training environments in orthopedic surgery [6, 9, 34–38].

Another emerging area revolves around the term ‘Internet of Things (IoT)’, which can play an important role in the development of distributed/web based collaborative framework in engineering, medical and other application contexts. IoT, in general, can be described as a network of physical objects or ‘things’ enhanced with electronics, software and sensors [20]; the ‘things’ refer to sensors and other data exchange or processing devices which are part of a connected network linking cyber and physical resources in various contexts.  In the healthcare and medical context, the adoption of IoT based approaches can be useful in reducing costs and improving the health care quality while facilitating use of distributed (and remote) software and physical resources. The term ‘Internet of Medical Things’ (IoMT) has been proposed by the researchers to refer to IoT for medical applications [21, 22]. However, the term IoMT can lead to misinterpretation as this term is also being used by manufacturing researchers to refer to ‘Internet of Manufacturing Things’ [23, 24]. We propose to use the acronym ‘IoMedT’ to refer to the Internet of Medical Things, which can be defined as an IoT network which links medical devices, software, sensors and other cyber/physical resources through a network to support various activities including tele-medicine, web based surgical training, remote patient monitoring, among others. In the surgical training context, IoMedT based approaches can provide collaborative training to the medial residents and students along with proving crucial patient data online to improve their surgical capabilities. The role of collaborative learning has been underscored by only few researchers in medical education; for such cyber training activities, users and students can interact from different locations through the Internet [25–29]. One such environment is discussed in [30] which outlines a collaborative VR based environment for temporal bone surgery. They used a private gigabit Intranet to send only the modifications in drill positions/forces through the network whereas the model was made available in both locations.  Another approach involving collaborative haptic surgical system is described in [25] where users can simulate surgical processes using virtual tools independently in two different locations. The literature shows an evident lack of cloud based training simulators through which medical residents can practice surgical steps remotely and collaboratively.

The use of cloud based approaches along with Virtual Reality (VR) based technologies can transform the way medical training is performed. Software Defined Networking (SDN) principles can be used to support such cloud based training approaches which not only reduce the complexity seen in today’s networks, but also help Cloud service providers host millions of virtual networks without the need for common separation/isolation methods [9, 15, 32]. In [15], a cloud based training framework to support haptic interface based training activities in LISS plating surgery has been discussed. Using such framework (figure 7), residents from different locations can interact with an expert surgeon who can guide them or supervise their virtual training activities in a collaborative manner. Initial results on the performance of the network as well as assessment of learning/training [8, 14, 39, 40, 43] have underscored the potential of such distributed approaches based on IoMedT principles.

Figure 7. A Cloud based IoMedT Framework for Surgical Training

Discussion

An important aspect to emphasize is that during the creation of these four VR based simulation platforms, the role of the expert surgeons was important. They were involved with the design, planning and development of the content of the training modules from the beginning; they provided reading materials and surgery videos along with discussing the surgical procedures in detail to ensure the software engineers gained a better understanding of the details involved. They also provided suggestions on improving the user interface and making it user friendly for the students and residents.

The impact of the four platforms supporting VR based training have been assessed through interactions with surgeons and medical residents at Texas Tech University Health Sciences Center, El Paso, Texas [7–9, 15, 39] and the Burrell College of Osteopathic Medicine (BCOM), Las Cruces, Mexico.

Survey based comparisons [6, 7, 14, 40] was conducted involving haptic based, IVR and MR based simulators; the criteria considered included:

Head movement/Comfort: did the users feel comfortable interacting with the training environments using the VR headsets? (Vive and HoloLens)

Field of view: how much of the training scenarios within the simulation environments could be seen when wearing when wearing the HoloLens or Vive device?

Navigation: how easy and intuitive were these platforms to allow users to explore a target training scenario including walking around, changing direction, zooming in on a specific area, etc. using a haptic pen (shown in figure 1), finger gestures in a HoloLens platform (figure 5) or a controller in a Vive platform (figure 3).

Ease of interaction: how easy was it for a user to interact with the training environment using the available user interface options?

Mobility during training: how much mobility did users have while interacting with the training simulator? (could they move freely or was their mobility restricted to a specific position during training)

The IVR simulator platform received a higher score on the first criterion. In terms of the Field of View, both IVR and MR simulators received comparable scores as both allowed a user to turn their heads and interact with the environment. In terms of Navigation, the three platforms (haptic, IVR and MR simulator) received similar scores. For criterion 4 (ease of user interaction), the controllers provided with the IVR simulator and the haptic simulators received a higher score than the MR based simulator (some users had difficulty using the finger gestures to interact with the user interfaces). For criterion 5 (Mobility during user interaction), the MR based simulator received the higher score as it allowed users unhindered movement during training. The IVR simulator had wires connected to the Headset which could potentially hinder or trip users when they were moving and navigating during a training session (the wires can be seen figure 3). The cost of these platforms devices were comparable. In general, the emergence of both the HoloLens and Vive based platforms provide a low cost alternative to the more traditional expensive VR environments such as the VR CAVE or Powerwall.

Conclusion

In this paper, a discussion of four simulator platforms for training medical residents in orthopedic surgery has been discussed. The four platforms discussed were haptic based, immersive, mixed reality based and distributed/web based platforms. These simulators were built to provide residents training in two orthopedic surgical procedures (LISS plating and condylar plating) to address fractures of the femur bone. A comparison of their interactive capabilities along with results from studies assessing their impact on education and training was also provided. The results from the learning interactions were predominantly positive and the comparison studies revealed that the low cost emerging platforms have the potential to be incorporated into medical training activities.

Acknowledgment

We would like to express our thanks to the surgeons, residents and students at the Paul L. Foster School of in El Paso (Texas) and Burrell College of Osteopathic Medicine (BCOM), Las Cruces, Mexico for participating in some of these project activities.

Competing interests

The author(s) declare(s) that they have no competing interests.

Funding Information

This material is based upon work supported by the National Science Foundation [under grant number CNS 1257803].

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DOI: 10.31038/SRR.2018112

Abstract

Purpose

The left ventricular assist device (LVAD) population is rapidly expanding. Unique characteristics, including lack of knowledge concerning LVADs and necessary anticoagulation, complicate acute traumatic injury.

Methods

A descriptive retrospective case series was created by cross-referencing our LVAD and trauma databases at our academic, Level 1 trauma center from 2004 – Present. A chart review was performed to obtain demographics, admission data, traumatic work-up and management, LVAD data, and outcomes.

Results

Three patients sustained traumatic injuries with a LVAD in place. None were admitted by the Trauma service; 2 had routine consultations, delaying imaging and injury diagnoses. Arrival vitals were not predictive of life threatening injuries; no palpable pulse with no recorded blood pressure. No mechanical pump complications resulted; 1 patient experienced a pump flow pulsatility/suction event.

Conclusion

Trauma providers must understand LVAD function to effectively evaluate these patients. Initial work-up should involve the trauma service to prevent delays in diagnosis and cardiothoracic surgery to evaluate the LVAD.

Keywords

Left ventricular assist device (LVAD); Trauma; Complications; Acute injury; Presentation

Introduction

Heart disease continues to plague Americans. It remains the leading cause of death for both men and women, and 1 out of every 4 deaths in America is due to heart disease [1]. For those with advanced or end stage heart failure aside from medical management, left ventricular assist devices (LVADs) are the most common therapy. Between 2,500 and 3,000 LVADs are implanted annually in the United States at nearly 200 facilities [2]. LVADs can serve as a bridge to heart transplantation (BTT) or as destination therapy (DT) for patients not meeting transplant eligibility which has exponentially increased the number of LVAD implantations in recent years [3]. Interestingly, one and two year survival rates of patients with LVADs is equivalent to those undergoing heart transplantation [4].

Despite this growing population of patients, some are transplanted and others destined never to be, few centers have LVAD programs, and even fewer providers are familiar with how LVADs function. Differing LVAD models and patient physiology will affect the presence of a pulse and requirements for anticoagulation. Emergency department providers in hospitals with LVAD programs may be primed to recognize common adverse events such as gastrointestinal bleeding, device thrombosis, and strokes but this is widely variable. Providers intimately involved with LVAD programs recognize aortic insufficiency, right ventricular failure, and driveline infections as serious complications which can lead to mortality, but unfortunately, literature about LVADs is primarily confined to cardiology and cardiothoracic surgery.

Following implantation, LVAD patients have an important improvement in their quality of life. Nearly 80% are satisfied with their decision to undergo implantation [2]. They are able to regain mobility and usual activities [5]. These patients are no longer house bound, return to driving, traveling, and partaking in risky behaviors such riding motorcycles. Therefore, they are at risk for traumatic injury and may present to facilities without LVAD programs receiving care from emergency department physicians, traumatologists, and intensivists – who may be unfamiliar with the presentation of a traumatically injured patient with an LVAD. The goal of this study was to review our cases of acute traumatic injuries in LVAD patients to better understand this patient population and approach to treatment.

Materials and Methods

Following IRB approval, we cross-referenced our LVAD and trauma registries at our academic, Level 1 trauma center from 2004 – 2017. We then created a descriptive, retrospective case series of patients appearing in both databases. A chart review was performed to obtain demographics, admission data, traumatic work-up and management, LVAD data, and outcomes.

Results

A total of 302 patients received LVADs at our Level 1 trauma center from 2004–2017. After the cross-reference process, 3 patients were identified as having sustained acute traumatic injuries with an LVAD in place. Following is a summary of each of their cases.

Case #1

A 74 year old male with a history of ischemic cardiomyopathy who had an Heartmate II LVAD in place for 4 years, 2 months, and 9 days as destination therapy at the time of his acute traumatic injury. He was not a candidate for transplant due to his high operative risk. His co-morbidities included renal insufficiency, chronic back pain, COPD, atrial fibrillation, hypothyroidism, and a 30-year pack year tobacco use. The patient was a restrained driver in a motor vehicle accident. He was traveling at 35 mph, got distracted and struck the back of another vehicle. Airbags were deployed. He denied loss of consciousness. He sustained bruising of his abdomen. He presented later that afternoon to his local infusion center for a transfusion and upon hearing the history, was sent to the nearest emergency department to be evaluated. Given the complex nature of his health, he was transferred to our tertiary center, arriving 7 hours post injury complaining of pain across his upper abdomen in a band-like distribution.

His vitals at the initial hospital and during transport demonstrated a heart rate of 70–100 with blood pressures of 90/palpable. At our facility, MAPs were recorded upon arrival until an arterial line was placed. The trauma service was the first service to document 2+ pulses symmetry throughout all extremities followed by the intensivists who documented bilateral radial and dorsalis pedis signals by Doppler, otherwise he was non-pulsatile.

Prior to transfer, the patient received a chest x-ray and CT head demonstrating a small acute tentorial and falcine subdural hematoma. He was directly admitted to our heart failure service who consulted our neurosurgical, cardiothoracic surgery and trauma services approximately 13 hours later. The trauma service ordered maxillofacial, chest, abdomen, and pelvis, cervical, thoracic, and lumbar spine CTs to complete his work-up. Injuries identified included a subdural hematoma, splenic laceration with associated hemoperitoneum, left 4–8 rib fractures, and right 4–7 rib fractures. The splenic laceration could not be graded and a liver laceration was suspected, however, the CTs were non-contrast due to the patients underlying renal insufficiency (Cr 1.5). His injury severity score was 29.

The patient was initially admitted to the floor, but given the patient’s subdural hematoma and therapeutic anticoagulation with warfarin, he was transferred to the ICU for frequent neurochecks. The patient had an INR of 2.48 at presentation with a lactic acid of 2.1, no leukocytosis, and a H/H of 7.6 and 26.8 respectively. Platelet count was 118. He initially received a transfusion of two units pRBCs due to a decrease in Hg to 6.4 on serial check. The patient’s warfarin was held at admission, and cardiothoracic surgery preferred not to give any reversal agents and restart the warfarin when all services were amenable. By hospital day (HD) 3, neurosurgery agreed to restarting warfarin and trauma was agreeable to restarting it on HD 4, so the first dose was given HD 4. Unfortunately on HD 5, the patient’s INR jumped to 3.7 and prothrombin complex concentrate 2500 units was given. Additionally, he was transfused 2 more units of pRBCs for worsening anemia and a stat CT angiogram of the abdomen was performed in anticipation of splenic embolization. During this time, he was transferred back to the ICU for close monitoring. Ultimately, the CT demonstrated no change and no further interventions or transfusions were necessary. He spent 6 of his 12-day hospitalization in the ICU and was discharged to a skilled nursing facility.

With regard to the LVAD, this patient did not have an EKG performed during this admission. An echocardiogram was performed hospital day 3 and a normal troponin was drawn at the transferring hospital with no repeats. His LVAD was interrogated during his hospital admission demonstrating low pulsatility indices (PIs) down to 1.7 post-accident, but no low PIs at the time of the accident. There was no evidence of device damage as a result of the motor vehicle crash. The patient did not receive any intervention for his traumatic injuries.

Case #2

This was a 72 year old female with a history of non-ischemic cardiomyopathy. At the time of her acute traumatic injury, her Heartmate II LVAD had been in place for 1 year, 5 months, and 22 days as destination therapy. Her co-morbidities included hypertension, chronic kidney disease, and diabetes. After standing up, the patient became unsteady, fell and hit her head. She did not recall any preceding symptoms of dizziness, lightheadedness, or palpations. She described the event as losing her balance and not being able to catch herself. She presented to the emergency department as a walk-in, complaining mainly of a headache.

Initially, heart rates in the 70s and no blood pressures were documented. The first documented blood pressure was 0/0 and a MAP of 110 five hours after her arrival. MAPs continued to be recorded without blood pressures. Pulses were not documented by emergency medicine. However, they were document as 2+ and symmetric by cardiology and nephrology, but 0/4 in all extremities bilaterally by cardiothoracic surgery.

The patient underwent a maxillofacial, head and cervical spine CT that were all negative. On physical exam, she had a 2 centimeter scalp laceration repaired by the emergency medicine providers
(ISS = 1). She, too, was admitted to our heart failure service to the general floor and cardiothoracic surgery and nephrology were consulted. She was hospitalized for 3 days of observation and discharged home with home health care.

On admission, her INR was 2.6 due to warfarin. Neither a lactic acid, nor troponin were checked. She had no leukocytosis, and her H/H was 10.1/33.7 with a platelet count of 339. She had an EKG performed on arrival, but no ECHO during her hospitalization. Her LVAD was interrogated and demonstrated normal values without any PI events. There was no evidence of device damage.

Case #3

A 51 year old male with a history of ischemic cardiomyopathy who had a HeartWare LVAD in place for 7 months and 25 days presented to our emergency department reporting two episodes of syncope the previous night. He initially had been listed for transplant but was delisted 2 months prior for drug use. His co-morbidities included hypertension, cardiorenal syndrome, pulmonary hypertension, chronic hyponatremia, tobacco abuse (quit 3 years prior), and drug abuse (methamphetamines). At presentation, he had an abrasion to his forehead and stated in the past week he had experienced worsening dizziness with falls. He could not recall all the events with accuracy. He reported 2 months of sobriety.

Initial blood pressures were recorded as 102/0 a little over two hours after arrival, followed by serial MAPs beginning 4 hours after arrival. Pulses were not documented until HD 2 by the critical care team as bilateral radial and pedal Doppler signals. Additionally, neither the trauma service nor emergency medicine documented a pulse or Doppler exam.

A CT head was obtained which demonstrated a 1.4 cm left cerebellar hyperattenuating lesion which appeared hemorrhagic and a 1.1 cm left temporal hypoattenuating lesion which was concerning for embolic cerebrovascular accident, intracranial abscess, or malignancy. Unfortunately, an MRI could not be performed due to the LVAD. The patient was admitted to the ICU by medical intensivists who consulted neurosurgery, cardiothoracic surgery, and nephrology. On admission, his WBC was 21 and blood cultures were sent that grew gram-positive cocci in pairs/chains within 12 hours. A lactic acid was not drawn and his H/H was 9.8/30.6 with a platelet count of 317.

This patient was anticoagulated with warfarin, and his INR on admission was 2.8. Due to his LVAD device, he was an elevated risk of embolic events. Thus, unless his head bleed worsened or he needed operative intervention, cardiothoracic surgery recommended keeping him his INR therapeutic. On HD 2, however, the patient had a 2 gram decrease in hemoglobin. Combined with the concern for septic emboli and malignancy, a CT chest, abdomen and pelvis were performed. A grade 3 splenic laceration (4 cm) with subcapsular hematoma with active bleeding and moderate hemoperitoneum was identified (ISS = 9). At this point 26 hours after admission, the trauma service was consulted. Fresh frozen plasma was transfused with a goal INR of 2.0. Serial hemoglobins were checked with the plan for embolization if the patient demonstrated continued transfusion requirements. He received FFP and 5 units of pRBCS within 24 hours. A repeat head CT was obtained and remained unchanged. Review of the first CT abdomen and pelvis was concerning for splenic pseudoaneurysms. Therefore, on HD 3, a repeat CT angiogram of the abdomen was performed which confirmed multifocal pseudoaneurysms in the spleen. The patient underwent successful selective embolization of these pseudoaneurysms and feeding arteries. He required no further transfusions, but did receive antibiotics for 1 month for strep viridans bacteremia. He was bridged back to warfarin with heparin beginning HD 6 after much deliberation amongst the teams. His brain lesions were felt to be hemorrhagic as his septic emboli work-up was negative except for bacteremia. He was discharged home after 11 days, spending 4 of those days in the ICU.

This patient had an EKG on HD 1, a transthoracic echocardiogram on HD 1, and a transesophageal echocardiogram on HD 3 to evaluate his LVAD and valves for vegetation. No troponins were checked. LVAD interrogation revealed stable parameters without any worrisome events. There was no evidence of device damage as a result of the MVC.

Discussion

A review of the literature demonstrates only a single other case series of trauma in LVAD patients. In 2013, Sarsam et al. described 4 patients who sustained external trauma; 3 falls and one blow to the chest [6]. Two of these patients from this series presented acutely, either immediately after the traumatic injury or at 48 hours, while one patient waited 3 weeks and another 14 months [6]. All readmissions, however, were due to device complication. Unfortunately, their report focused on damage to the LVAD, presentation of symptoms related to the LVAD and the operative findings of the damage [6]. To our knowledge, this case series is the first report of traumatic injury in LVAD patients and the findings and considerations at the time of presentation.

There is a paucity of literature about the presentation of these patients and a lack of general understanding about initial management [6,7]. This is evidenced by the varying documentation of the pulse exam and blood pressures in our cases. Providers unfamiliar with LVADs may not understand the continuous blood flow from the LVAD and that pulses may be thready or absent, therefore must be listened to with a Doppler. Additionally, systolic and diastolic blood pressures cannot be technically obtained, but mean arterial pressures are trended even by arterial line if needed. This poses a problem to initial providers who are taught to recognize hemorrhagic shock in traumatically injured patients by tachycardia, a narrowed pulse pressure, and hypotension. Kenyhercz et al. describes this distraction in emergency medicine simulation where learners were disoriented by the LVAD, had little to no knowledge regarding the mechanics or physiology of an LVAD, and therefore, failed to implement Advanced Trauma Life Support (ATLS) resulting in the failure to diagnose life threatening injuries resulting in the death of the simulated patient [8]. This was echoed in our third case with the splenic laceration. In fact, the providers involved considered the acute anemia to be a result of hydration and did not consider a hemorrhagic traumatic injury. The lack of consideration of traumatic injuries is echoed numerous times in the INTERMACS reports [2,4], and even the article “How to Manage the Patient in the Emergency Department With a Left Ventricular Assist Device” only mentions fall with hematoma [9]. Emergency department presentation focuses solely on feared complications of the LVAD and anticoagulation that lead to death, gastrointestinal bleeding, device thrombosis, and strokes, and not the potential for life threatening injuries [9]. Sen et al. does state ATLS protocols should be followed and device malfunction needs to be assessed immediately [10]. While ensuring the VAD coordinator and cardiothoracic surgery team are consulted, a failure echoed in the simulations, Sen et al. does not mention involvement of the trauma service or a trauma surgeon who knows the indicated imaging, concerns, and management of common injury patterns [8].

In our cases, the involvement of the trauma service earlier may not have changed the outcomes, but may have identified injuries earlier changing the plan of anticoagulation reversal. This decision certainly must be made in a multidisciplinary fashion dependent on the patient, type of LVAD, and injuries present with risks and benefits weighed. Unfortunately, at this time there is too little data for any generalized recommendations.

Conclusion

To our knowledge, this is the first report of acute traumatic injury in LVAD patients. Trauma providers (emergency medicine or trauma surgeons) must have an understanding of LVAD function to effectively evaluate these patients, especially if practicing in an area with a robust LVAD and heart transplant program. This includes an understanding of vital sign interpretation, physical exam findings, and need for anticoagulation. Admission may be to a trauma service or cardiology, heart failure, heart transplant, or critical care team. Ultimately, the involvement of a trauma surgeon can prevent delays in diagnosis. The device will need interrogated for pump flow events and to ensure no damage has occurred. However, the decision to reverse anticoagulation and method by which this should be completed must be a collaborative decision.

Acknowledgements

Candice M. Thompson, MSN, RN, CEN

Timothy R. Ryan, APRN-NP

Conflict of interest

The authors, Lisa Schlitzkus, Brett Waibel, John Um and Zachary Bauman, have no conflicts of interest.

Human and animal studies

The study was conducted in accordance with all institutional and national guidelines for the care and use of laboratory animals.

References

1. Centers for Disease Control and Prevention. Heart Disease Facts.
   https://www.cdc.gov/heartdisease/facts.htm
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8. Kenyhercz WE, Perez JL, Wolfe AN, et al. (2017). Trauma Resuscitation in a Left Ventricular Assist Device Patient: An Emergency Medicine Simulation Scenario. Cureus 9(10): 31773. DOI 10.7759/cureus. 1773 [Crossref]
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DOI: 10.31038/SRR.2018111

Abstract

Reconstruction and restoration of dura is an important issue in many cases of craniotomy. In cases that must be replaced large defects of dura, the usage of artificial dura is increasing.

During the period between 2013 till 2017, a total of 94 patients who underwent craniotomy for various reasons and collagen Dural plates were applied for Dural defects repairing were recruited to the study. During the follow-up of these patients, 10 patients were excluded from the study, which from the total of the remaining 84 patients, 11 cases of infection “13%” were observed. Eight cases of infection occurred as subdural empyema which were cured with reoperation treatment and evacuation of pus and dural repair. Cerebrospinal fluid leakage was seen 15.4% in 13 patients that all of them were improved with non-surgical supportive care.

Conclusion

With regards to the ease of using and least complications associated with the use of these artificial dural plates, it can be recommended to use it to dural restoration in the various craniotomy surgeries

Introduction

Proper Dural repair should be done to prevent cerebrospinal fluid leakage occurrence in craniotomy with any reason. In the cases that the primary defect of dura is too large that cannot be restored by the primary Dural tissue of the brain, we have to use alternatives to repair the underlying Dura. It is recommended to use a various type of dural alternatives that include the use of fasciae latae or peri-cranial tissue or artificial synthetic dura or ultimately tissues derived from allografts (cadaveric Dura) that each one has its own advantages and disadvantages [1–5].The usage of fasciae latae auto grafts don’t have much attractive due to the need for cutting and additional procedures with possible complications and pain caused by the removal of grafts ‘site or in cases where there are some reports from transmission of Creutzfeldtjakob caused by the use of allograft cases[6–8]. Synthetic collagen dural sheets are also safe alternatives to use as dural repair; because they are both easy to use and their reports of granulomatous reaction occurrence are rare[5, 9–12].In this study, we have discussed about results of the use of “ Aesculap onlay dura mater “ which exist as an artificial sticky sheets of Dura.

Materials and method

During the period between2013 till 2017, a total of 94 patients who underwent craniotomy for various reasons and collagen Dural plates were applied for Dural defects repairing were recruited prospectively to the study. The reasons that Patients were undergoing craniotomy include: tumors, brain hemorrhages, cerebral infarction and cerebro-vascular disease. In the process of dural restoration, we have used absorbable collagen plates of Dura “Aesculap onlay dura mater” in the size of 10cm × 10cm for each patient based on the underlying dural defects. These plates have been made of the underlying collagen scaffolds [10–12]. Sheets application is without the need for suture them to underlying dura. It will be embedded with the cover margin of at least 1cm from surrounding healthy Dura on the defect site (figure 1). Patients were followed up for three months after surgery. During the follow-up period, 10 patients died in a short period after surgery due to underlying medical conditions and were excluded from study. Of the remaining 84 patients, 25 patients “29.7%” had been subjected to surgery because of trauma, and 11 patients “% 13” had undergone craniotomy for brain infarction, 15 patients (17.8%) due to cerebral hemorrhage, and 12 patients “14.2%” for brain tumor and 21 patients “% 25” followed by cerebro-vascular lesions. (Table 1)

Table 1. Collagen dura usage results in patients

Figure 1. Collagen tissue dura sheets application

Underlying dural defects in traumatic bifrontal craniotomy , without the need for suture collagen tissue dura sheet is embedded with the cover margin of at least 1cm from surrounding healthy Dura on the defect site.

Results

Totally, infection was observed in 11 patients (13%) during follow-up period (Table1). According to the clinical and MRI findings, eight cases “% 9.5” were diagnosed as subdural empyema infection. sub-galeal space infection in three cases (3.5%). Diagnosis of sub-galeal space infection was obtained by pus discharge at the incision site and MRI findings. The cerebrospinal fluid leakage was observed in a total of 13 patients (15.4%) as a discharge of cerebrospinal clear fluid secretions from the incision site during the follow-up period. Of the total cases suffered from leakage, six cases of them were underwent surgery for cerebro-vascular lesions (46%) and four cases underwent surgery for traumatic brain injury (% 31); tumor and brain hemorrhage were constituted two patients (15%) and one patient (8%) respectively (Chart 1). All of CSF leakages were treated by conservative measures; however, there were three cases from four patients with cerebrospinal fluid leaks among patients undergoing surgery due to traumatic events experiencing subdural empyema. Two cases of cerebrospinal fluid leakage were among patients that undergoing surgery due to cerebro-vascular lesions who were experiencing subdural empyema. Cerebrospinal fluid leak in patients with cerebral hemorrhage and brain tumors has been improved by the conservative measures generally and none of the cases led to subdural empyema, or infection.

Chart 1. Rate of CSF leakage in different causes of craniotomy

Epidural accumulation of pus was occurred in all the three patients that two of them were observed in traumatic patients and one case occurred in a patient who was undergoing surgery due to brain hemorrhage. Subdural empyema patients were undergoing reoperation and the products of previous synthetic dura and pus collection were irrigated and evacuated completely, so that it was used from fasciaelatae autograft tissue to repair dural defect. After drainage, washing and continuing antibiotic treatment, six patients of a total of eight patients with subdural empyema were improved completely and pus accumulation in the subdural space was resolved in subsequent imaging and did not recur. These two patients were again subjected to surgery and re-drainage of the pus and subdural space washing due to the formation of pus in the subdural space that full recovery was observed with surgical repetition in these patients.

Of the three patients with sub-galeal accumulation, all of them were initially subjected to reoperation and pus discharge from the space of sub-galeal. One patient had fully recovered by this action and re-accumulation of pus was not found, but two other patients were undergoing surgical removal of previous synthetic dural tissues and replacing it with autograft Fasciae latae tissue due to re-accumulation of pus in follow-up MRIs which finally resulted in complete remission in these patients.

Discussion

Overall, infections in our patients was ultimately 13% during follow-up period. Infection rate of traumatic patients was totally more than the other groups that were subjected to surgery [54% of overall infection cases]. The least infections were among patients with cerebral infarction (no patient).

According to the Setsuko et al. (2003) which finally completed on 56 patients[13].The overall infection rates(14.3%) were reported in the use of artificial dural plates which was slightly higher than our study of collagen plates in the repair process. The percentage of sub-dural empyema incidence was reported 12.5% after the use of Dura plates here. While it has been observed 9.5% in our research.

Generally, the incidence of CSF leakage has been reported between4 -17% in other studies [14, 15], that is defined as sub-galeal accumulations of cerebrospinal fluid and its outflow through the sutures or its surrounding areas as the rhinorrhea or othorrhea . Totally, cerebrospinal fluid leakage was 15.4% in all of our studied patients. Highest amount of observed leakage was happened among the patients undergoing surgery for cerebro-vascular lesions “46%”, and the lowest amount was in patients undergoing surgery for cerebral infarctions that no case of leakage was found among them. The CSF leakage in patients who subjected to cerebro-vascular lesions surgery may be due to the need for a wider dissection in the sub-arachnoid space during surgery to create a wider space and visibility.

In the research of Than ko (2008), the amount of CSF leakage in the patients who had been used artificial dura to repair dural defects, was reported10%[14]. Huttera et al (2014) did not report any advantage in the reduction of CSF leakage by this method on patients using artificial dura as a normal suture compared to the use of artificial dura as a strengthening method; but in general, announced their two groups of patients CSF leakage incidence as 13.5% [15].

In general, it has been used artificial collagen plates in the studies and have shown good results, also the granulomatous reactions are relatively little to it. According to the present studies, fibroblastic cells begin to multiply after about a month in underlying tissue of artificial dura and coverage of fibroblastic tissue will be created along with surrounding dura [16, 17].

In our study, all the patients with subdural or sub-galeal infections were eventually recovered completely by reoperation, washing and removing the remnants of artificial dura and using fasciae latae tissue to repair underlying dura.

By comparing the results of similar studies in the use of artificial dural plates and the results of our study, the acceptable complications rate and control power to prevent the cerebrospinal fluid leakage incidence was perfect in the use of artificial dural plates, although using this material could be imagine a proper alternative to dural repair and prevention of a cerebro-spinal fluid leakage considering to the easiness of these artificial dural plates and no need to remove autograft tissue to repairing dura, which has its own complications.

Conclusion

With regards to the ease of using and least complications associated with the use of these artificial dural plates, it can be recommended to use it to dural restoration in the various craniotomy surgeries.

References

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