Amir Manbachi
Dr. Manbachi is an Assistant Professor of Neurosurgery, Biomedical Engineering, Mechanical Engineering, Electrical and Computer Engineering at Johns Hopkins University. He is the engineering co-PI on a $13.48M award from Department of Defense, and responsible for the assembly of a world-class team of pioneers, including 60 individuals from clinic, academia and industry. He is the co-Director and founder of the HEPIUS Innovation Labs, focusing on the next generation of wearables and implantable medical ultrasound devices for spinal cord injury patients.
His research interests include applications of sound and ultrasound to various neurosurgical procedures. These applications include imaging the spine and brain, detection of foreign body objects, remote ablation of brain tumors, monitoring of blood flow and tissue perfusion, as well as other upcoming interesting applications such as neuromodulation and drug delivery. His pedagogical activities has included teaching engineering design, innovation, translation and entrepreneurship as well as close collaboration with clinical experts in Surgery and Radiology at Johns Hopkins.
His doctoral work embodied the development of ultrasound-guided spine surgery. He obtained his PhD from the University of Toronto, under the supervision of Dr. Richard S.C. Cobbold. Prior to joining Johns Hopkins, he was a postdoctoral fellow at Harvard-MIT Division of Health Sciences and Technology (2015-16) and the founder and CEO of Spinesonics Medical (2012–2015), a spinoff from his doctoral studies.
Amir is an author on > 40 journal articles, > 55 conference proceedings, ~ 20 inventions, a book entitled “Towards Ultrasound-guided Spinal Fusion Surgery” and an Audiobook entitled "Handbook for Clinical Ultrasound". He has mentored 170+ students, has so far been raised $15M of funding and his interdisciplinary research has been recognized by a number of awards, including UToronto’s 2015 Inventor of Year award, Ontario Brain Institute 2013 fellowship, Maryland Innovation Initiative and Johns Hopkins Institute for Clinical and Translational Research's Career Development Award.
Dr. Manbachi has extensive teaching experience, particularly in the field of engineering design, medical imaging and entrepreneurship (both at Hopkins and Toronto), for which he received the University of Toronto’s Teaching Excellence award in 2014, as well as Johns Hopkins career centre's nomination for students' "Career Champion" (2018) and finally Johns Hopkins School of Engineering's Robert B. Pond Sr. Excellence in Teaching Excellence Award (2018).
Supervisors: Youseph Yazdi, Nicholas Theodore, Alan R. Cohen, Richard SC Cobbold, Paul Santerre, Ali Khademhosseini, Mark Luciano, Henry Brem, and Betty Tyler
His research interests include applications of sound and ultrasound to various neurosurgical procedures. These applications include imaging the spine and brain, detection of foreign body objects, remote ablation of brain tumors, monitoring of blood flow and tissue perfusion, as well as other upcoming interesting applications such as neuromodulation and drug delivery. His pedagogical activities has included teaching engineering design, innovation, translation and entrepreneurship as well as close collaboration with clinical experts in Surgery and Radiology at Johns Hopkins.
His doctoral work embodied the development of ultrasound-guided spine surgery. He obtained his PhD from the University of Toronto, under the supervision of Dr. Richard S.C. Cobbold. Prior to joining Johns Hopkins, he was a postdoctoral fellow at Harvard-MIT Division of Health Sciences and Technology (2015-16) and the founder and CEO of Spinesonics Medical (2012–2015), a spinoff from his doctoral studies.
Amir is an author on > 40 journal articles, > 55 conference proceedings, ~ 20 inventions, a book entitled “Towards Ultrasound-guided Spinal Fusion Surgery” and an Audiobook entitled "Handbook for Clinical Ultrasound". He has mentored 170+ students, has so far been raised $15M of funding and his interdisciplinary research has been recognized by a number of awards, including UToronto’s 2015 Inventor of Year award, Ontario Brain Institute 2013 fellowship, Maryland Innovation Initiative and Johns Hopkins Institute for Clinical and Translational Research's Career Development Award.
Dr. Manbachi has extensive teaching experience, particularly in the field of engineering design, medical imaging and entrepreneurship (both at Hopkins and Toronto), for which he received the University of Toronto’s Teaching Excellence award in 2014, as well as Johns Hopkins career centre's nomination for students' "Career Champion" (2018) and finally Johns Hopkins School of Engineering's Robert B. Pond Sr. Excellence in Teaching Excellence Award (2018).
Supervisors: Youseph Yazdi, Nicholas Theodore, Alan R. Cohen, Richard SC Cobbold, Paul Santerre, Ali Khademhosseini, Mark Luciano, Henry Brem, and Betty Tyler
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particular, the use of excessive power is undesirable from a regulatory standpoint. Here, we report the design, development, and
cadaveric testing of a novel HIFU device for brain tumor ablation. This device is designed to access the ventricular space via a minimally invasive burr hole in the skull (Fig. 1a). This approach allows ultrasound to reach targets deep in the brain, while eliminating the need for high-power transcranial ultrasound procedures. (Manbachi et al. 2018, PCT)
Materials and Methods: As shown in Fig. 1b a custom, transducer with a hybrid imaging/HIFU tip was designed and manufactured, based on prior simulation studies (Zhang et al. 2017, AAPM; Gamo et al. 2018, AANS). Once the transducer was verified to be functional in a phantom model, a cadaver trial was performed to demonstrate proof-of-concept in ablating a
predetermined region of interest. Following ablation, the brain was sectioned to verify that the transducer ablated the predicted location, and according to the criteria outlined in Fig. 1c.
Results and Discussion: The transducer was successfully inserted into the ventricular space through a burr hole in the skull of a cadaver, and was used to create single-point ablations in the regions of interest, 3 cm away from the surface of the transducer. These data showed similar accuracy relative to that of transcranial approaches, but with considerably less power (12-35 W vs. 800 W with the transcranial approach).
Conclusions: A hybrid imaging/therapeutic ultrasound transducer was designed and manufactured to be inserted into the ventricular space through a minimally invasive burr hole in the skull. The performance of this probe was validated through precise ablations of deep intracranial pathology at low power in a cadaver. Thus, our solution presents a compromise between quality of care (treatment of oncology lesion) and patient safety (amount of applied power). Based on these findings, a beta
prototype will be developed to ablate medium to large size tumors.
Acknowledgements: This work was supported by the TEDCO Maryland Innovation Initiative Technology Validation Grant and Johns Hopkins University, Whiting School of Engineering’s Cohen Translational Fund awarded to AM. The authors thank Maryland Development Center and SonicConcepts for fruitful collaborations.
References:
Zhang et al. 2017, AAPM
Gamo et al. 2018, AANS
Manbachi et al. 2018, PCT/US18/20159
During 2012, around 700,000 spinal fusion surgeries were performed in the United States that required the insertion of screw implants. Although the procedure is to some extent routine, there is an inherent error rate when surgeons employ manual feedback techniques. The introduction of image-guidance methods has the potential to reduce the error rate [1]. One approach is to use ultrasound imaging from within the pedicle borehole so as to image the cortical bone boundaries. If the probe is a radial imaging array, then real-time visualization of the anatomy can be achieved: however, because of the very high attenuation in bone it is necessary to use much lower frequencies than those used in intravascular imaging.
Material and Methods:
Using a single element transducer, we previously demonstrated the capability of 1-3 MHz frequency ranges for this application [2]. We have now progressed from a single element transducer to a radial array. By electronic steering the need for transducer rotation is eliminated and, potentially enables the probe tip to be incorporated with the surgical toolkit that is used for advancement of pathway within the pedicle. We have designed and fabricated a 32 element, 2 MHz radial imaging array with a diameter of 3.5 mm. Using the matching circuit shown below the probe is designed to be connected to an Ultrasonix SonixTablet platform.
Results and Discussions:
We have designed and fabricated a low-frequency radial array transducer that demonstrates ‘proof of principle’. Details of the prototype and the results of testing on human pedicle bone samples will be presented (Research Ethics Approval Protocol No. 29799). The challenges of designing an array to operate at a sufficiently low frequency will be discussed. This is necessary so that the depth of penetration is sufficient to enable reflections from the cortical walls to be imaged with adequate resolution.
Conclusions:
A 32 element, 2 MHz radial imaging ultrasound array has been developed for use in spinal surgery. Long-term implications of this research should enable a small, portable, easy-to-use ultrasound-imaging probe to function in a seamless manner during surgery and which can provide the surgeon with real-time guidance for accurate pedicle screw insertion.
Acknowledgements:
The authors would like to thank Mike Lee and Dr. Stuart Foster from the Device development laboratory at Sunnybrook Research Institute and also Zamir Khan and Xiaoming Guo from Centre for Imaging Technology Commercialization for support during the fabrication and development of the probe.
References:
[1] Manbachi, A., Cobbold RSC, and Ginsberg HJ, The Spine Journal, 14, 165-179, 2014
[2] Aly AH, Ginsberg HJ and Cobbold RSC, Ultrasound Med Biol., 37, 651-664, 2011
The complex nature of ultrasound propagation in bone is partially due to the complex inner structure of bone. Cancellous bone, found in the inner parts of bones, consists of a porous spongy structure with a three-dimensional network of connected plates/rods, called trabeculae. In vivo, the cavities formed by trabeculae network are filled with bone marrow and fat. While it may appear that the trabeculae are randomly oriented, they tend to align in the direction of the applied stresses. For example, in bones where loading is largely uniaxial (e.g. vertebrae) the trabeculae frequently develop columnar structures.
The transmission of an ultrasound pulse in trabecular bone results in two longitudinal waves with differing speeds, similar to that predicted by the Biot theory. We are currently investigating the propagation of these fast and slow waves in columnar structures with anatomically relevant scales. The results of our numerical simulations and experimental measurements will be presented.
Materials and Methods: To collect data for model validation, a constant flow rate infusion pump (PHD 2000 Infusion, Harvard Inc, USA) was used to flow water through a Codman Hakim Precision valve at rates ranging from 0.1 ml/min to 10 ml/min. Compared to an average physiological rate of 0.60 ± 0.59 ml/min from 9 patients with normal pressure hydrocephalus [5], we chose a diverse array of flows because the CSF flow a patient experiences is highly variable. Ball position data was collected using a Parco Scientific 1080P Digital Microscope. Five measurements for each flow were collected and then averaged. Outliers - defined as values greater than 1.5 times the interquartile range - were eliminated from our data. After quantifying the displacement with ImageJ, we generated a trend line for the data.
Results and Discussion: Figure 1 shows the positive correlation between flow rate and ball displacement. For a linear fit of all 9 points, R2 = 0.8904. However, it also appears that the valve may occupy two states - ‘closed’ up to around 6 mL/min, and opening between 6 and 8 mL/min. This is
because our 4 initial flow rates have overlapping error bars while the final three points have overlapping error bars.
Conclusions: A possibly linear relationship was identified between ruby ball displacement flow rate in the Codman Hakim Precision Valve.
Currently, in order to obtain the spinopelvic parameters necessary to diagnose ASD, clinicians hand measure spinopelvic
parameters on whole spine radiographs2. This archaic method is both time consuming and inaccuracy prone. This abstract reports
on a design project aimed at automating the drawing and measuring angles to determine parameters in radiographs. The algorithm
will replace hand drawn lines and hand measured angles. It can be run in less than 3 minutes, and will ensure the angles are
determined more accurately than by manual measurements.
Materials and Methods: The project was done in the MATLAB coding environment (MathWorks, Massachusetts, USA). The
clinician uploads a radiograph, then clicks two points to specify the vertebrae needed to calculate the spinopelvic parameters. The
code makes use of well-established image processing techniques such as Canny and Sobel edge detection to assist the clinicians in
specifying the vertebrae. The code turns the clicked points into vectors and calculates the angle between them using the
arctangent function. Between now and the conference in October, a comparison of the accuracy of the automated angle
calculation vs hand measuring will be performed with 3 surgeons on 3 radiographs and the results will be presented
Results and Discussion: The automatically calculated angles for the Cobb angle, Thoracic Kyphosis (TK), Lumbar Lordosis
(LL) and the C7 plumb line were compared to hand measured angles. The calculated angles for TK, LL and Cobb were within 3
degrees of the hand measured angle. Despite our initial hypothesis regarding better accuracy for the automated method, accuracy
is still highly dependent on the user clicking on the vertebrae locations correctly. Another challenge of the reported method is
many radiographs have relatively low contrast to background ratios and the spinal bones have blurry edges, making it difficult to
see where vertebrae end. Such limitations can influence the effectiveness of the edge detection and other image processing tools.
Conclusions: In this study, we reported the design, development, and evaluation of an automatic method to calculate and report
spinal deformity angles within 3 minutes. As shown by retrospective studies, the number of patients who undergo spinal surgery
with improper diagnoses is large3, and compared to manual hand measurements, this technique has the ability to not only reduce
error rates and provide better patient safety but also deliver the required angle measurements faster.
Acknowledgements: The authors would like to thank Johns Hopkins University’s Department of Biomedical Engineering
Undergraduate Design program and the Center for Bioengineering Innovation and Design (CBID).
References:
- Schwab, F. J., MD, Blondel, B., MD, Bess, S., MD, Hostin, R., MD, Shaffrey, C. I., MD, Smith, J. S., MD, PhD, . . . Lafage, V., PhD. (2013). Radiographical Spinopelvic Parameters and Disability in the Setting of Adult Spinal Deformity. Spine, 38(13), E803-E812.
- Cavanilles-Walker, J. M., Ballestero, C., Iborra, M., Ubierna, M. T., & Tomasi, S. O., MD. (2014). Adult Spinal Deformity: Sagittal Imbalance. International Journal of Orthopedics, 1(3), 64-72. Retrieved February 22, 2018.
- Yanamadala, V., Leveque, J. A., & Sethi, R. K. (2017). Misdiagnosis Is a Prevalent Cause of Inappropriate Lumbar Spine Surgery. The Spine Journal, 17(10).