This study was partially supported by Point Robotics Medtech Incorporation, which provided the robot system. The funder provided support in the form of salaries for X.Y. Xiao, C.W. Chen, H.K. Chou, and C.Y. Sung, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

All procedures followed were in accordance with the ethical standards of the National Taiwan University Hospital (NTUH) Research Ethics Committee (REC) and the Helsinki Declaration of 1975 (in its most recently amended version). Informed consent must be obtained from all patients if further clinical trial is prepared.
NOTE: The anesthesia procedure can be categorized into three steps: pre-operative evaluation of the patient, intraoperative management, and postoperative management. During pre-operative evaluation, all patient data, including the thorough history and physical examination, should be collected and the staff should recognize patient comorbidities and how they relate to the anesthetic care of the patient. A thorough airway exam should be performed, and the staff should be aware of the anesthetic options to formulate a basic anesthetic care plan. During intraoperative management, the anesthesiologist should check the basic functions of the anesthesia machine, and apply basic physiologic monitors recommended by the American Society of Anesthesiologists, which include a pulse oximeter, electrocardiography, a noninvasive blood pressure device, and a temperature monitor, airway management options, pharmacology of inductions agents, and indications during an anesthetic induction. Intraoperative events, such as hypotension, hypertension, hypoxia, and oliguria, must be recognized, evaluated, and managed. Additionally, the staff must recognize when the patient meets the extubation criteria.
1. Pre-operative setting and planning
NOTE: During surgery, sterile surgical drapes should be used to prevent contact with unprepared surfaces and to maintain surgical site sterility of the environmental surfaces, equipment, and patient&#8217;s surroundings. To reduce the risk of pathogen transmission to both the patients and the surgical team, sterile surgical gowns should be worn over the scrub suits by the operating team during surgery.
<ol>
	<li>Remove all components that can affect fluoroscopy from the surgical site; this depends on the surgical plan according to each individual patient.</li>
	<li>Place the patient in a prone position after administering anesthesia and prepare as per surgical requirements. 
	NOTE: All anesthesia procedures must be performed under the supervision of an anesthesiologist and each plan should be adjusted according to each individual patient.</li>
	<li>Clean and sterilize the surgical site of the patient.</li>
	<li>Cover the OP-site at the surgical site of the patient.</li>
	<li>Place the sterile surgical drape on the patient, except at the surgical site.</li>
	<li>Anchor the FF to the patient; users can choose one of the following two methods according to their needs.
	<ol>
		<li>Anchoring to the iliac bone (applicable surgical site: L5 or S1).
		<ol>
			<li>Place two percutaneous wires (&#934; = 1.5 mm) on the posterior iliac crest and check the entry point under fluoroscopy. Repeat the step if surgeon has a concern about the entry point. Mark the entry point by using a marker pen.</li>
			<li>Insert the first percutaneous pin (&#934; = 5 mm, L = 140 mm) into the patient&#8217;s posterior iliac crest by using a power drill (1000 RPM).</li>
			<li>Place the FF along with the first percutaneous pin. Adjust the FF until it is recognized by the optical tracking camera. Fix the FF to the first percutaneous pin using a screwdriver.</li>
			<li>Insert the second percutaneous pin (&#934; = 5 mm, L = 140 mm) along with a hole on the FF using a power drill (1000 RPM). Fix the screw on the FF to the second percutaneous pin using screwdriver. 
			NOTE: According to the manual of the optical tracking system, the marker sphere can be identified within 3 m from the optical tracker.</li>
		</ol>
		</li>
		<li>Anchoring to the current or adjacent vertebral spinous process with a clamp applicable surgical site: thoracic, lumbar, or sacral vertebrae.
		<ol>
			<li>Place a wire (&#934; = 1.5 mm) on the patient&#8217;s back as a reference under fluoroscopy. Check the surgical field under fluoroscopy. Repeat the step if surgeon has a concern about the surgical field. Mark the surgical field by using a marker pen.</li>
			<li>Incise the skin tissue on surgical field using a surgical scalpel. Fix the FF to the spinous process using a screwdriver. Due to the difference of bone mineral density, have the surgeon determine if the FF is anchored on spinous process firmly.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Check whether the equipment and components of PSNS have been prepared, including the handpiece, the optical tracking system, the robotic workstation, and the navigation toolkit (i.e., probe) (Figure 3 &#38; Figure 4). 
	NOTE: Avoid interfering with the surgical staff; Avoid blocking the optical tracking camera; Ensure the tracker is stable and recognized by the optical tracking system; Sterilize the navigational toolkit and place it on the operating table.</li>
</ol>
2. Spatial labeling and registration
<ol>
	<li>Transfer the patient&#8217;s preoperative CT images to the system through DVD or USB and crop the image size to adjust the orientation based on surgical needs. The system provides virtual surgical guided images, including sagittal, coronal, axial, and oblique planes, and customized 3D reconstructions for each vertebra.</li>
	<li>As the PSNS software provides the labeling interface, ask the surgeon to label each vertebra with the anterior-posterior view and lateral view, differentiating the intervertebral disc for the subsequent steps to be identified.</li>
	<li>Select the optimal screw length and implant dimensions based on the device software.</li>
	<li>Plan the optimal positioning and trajectory of the screw based on the 3D and multi-planar image reconstruction of the preoperative CT scan.</li>
	<li>Confirm whether all the planned screws are correct and appropriate.</li>
	<li>Enter the DRF monitoring interface in the PSNS software that presents multiple planar views (include 3D volume and three cross-sectional planes on the side). All the DRFs should be inside the vision area of the optical tracking system (according to the user instructions, the recommended best recognition range is range B.) When the DRF vector arrow indicating the tracker is displayed on the user interface, it is stably recognized by the tracking system (Figure 5).</li>
	<li>Perform a subperiosteal dissection bilaterally along the spinous process, the laminae out to the tips of the transverse processes of all the levels. Remove the facet joint capsules to expose the joints. The use of self-retained retractors aid in vertebra exposure by holding the musculature off to the side.</li>
	<li>Perform registration procedures, including landmark registration and surface matching. Follow the sequence below to ensure the correctness of the registration result.
	<ol>
		<li>Landmark registration
		<ol>
			<li>Select at least four non-coplanar feature points (such as the spinous process, the laminar, and the transverse process) on the patient&#8217;s pre-operative 3D reconstruction CT images.</li>
			<li>Use the tip of probe to keep in contact with the first feature point selected in step 2.8.1.1 in the actual surgical area.</li>
			<li>Press the probe selection button on the software interface to confirm the access point.</li>
			<li>Repeat steps 2.8.1.2-2.8.1.3 until the four feature points selected in step 2.8.1.1 are confirmed.</li>
			<li>Press the calculation button on the software interface; the system will calculate the result of the landmark registration and present it in the software interface.</li>
			<li>The acceptance criteria for the registration accuracy must meet the needs of the clinical indications (&#60;5 mm). If the result is not satisfactory, repeat steps 2.8.1.1-2.8.1.5 until the registration result meets the acceptance criteria. 
			NOTE: Ensure that the validity of using the probe to obtain the position information of the bone surface, such as clearing the soft tissue on the bone surface and avoiding the dangling of the probe tip when collecting points.</li>
		</ol>
		</li>
		<li>Surface matching
		<ol>
			<li>Use the probe tip to continuously contact any point on the bone surface in the actual surgical area.</li>
			<li>Press the probe selection button on the software interface to confirm the access point</li>
			<li>Move the probe (make probe different from previous pick point), and repeat steps 2.8.2.1-2.8.2.2 until at least 50 pick points are completed.</li>
			<li>Press the calculation button on the software interface; the system will calculate the surface matching result and present it on the software interface.</li>
			<li>The acceptance criteria for the registration accuracy must meet the needs of the clinical indications (&#60;0.5 mm). If the result is not satisfactory, repeat steps 2.8.2.1-2.8.2.4 until the registration results meet the acceptance criteria.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Use the probe to select obvious anatomical landmarks (such as spinous process, transverse processes, facet joint) of the actual surgical area for confirmation once the registration result is accepted (Figure 6). 
	NOTE: Appropriate reflection and reception of the infrared light must be maintained during surgery. If the optical tracking system cannot recognize the markers, the software interface will display a red light reminder. The camera should be adjusted such that the surgical field is at the center of the camera&#8217;s detection range, and the tracker should be protected from light and blood.</li>
</ol>
3. Robot assembly and motion
<ol>
	<li>Cover the handpiece with sterilization drapes and install the surgical instruments on the robot (e.g., trocar (&#934; = 5 mm) and k-pin (&#934; = 1.8 mm)).</li>
	<li>Adjust the angle and position of the handpiece in space according to the following instructions (steps 3.2.1-3.2.2) so that the handpiece is within the compensation range (within a distance of one centimeter and an included angle of 4 degrees from the planned path).
	<ol>
		<li>Angle adjustment: Turn the angle of the handpiece in space so that the two circles representing the angle of the handpiece coincide on the software interface.</li>
		<li>Position adjustment: horizontally and vertically move the position of the handpiece in space, so that the dots representing the position of the handpiece on the software interface are aligned with the entry points of the planned path. 
		NOTE: When steps 3.2.1 &#38; 3.2.2 are completed at the same time, the handpiece will automatically activate the active compensation function to maintain the angle and position of the instrument to conform to the pre-planned path (Figure 7).</li>
	</ol>
	</li>
	<li>Determine the robot&#39;s operating status by judging the marker color of the robot displayed on the UI. If it is green, it can be operated, if it is red, it cannot be operated. 
	NOTE: If the handpiece comes in contact with the patient or the surrounding obstacles, an emergency stop button located above the navigation workstation housing can be pressed by the surgeon or technician. Regular maintenance of the robot should be performed. The platform must be recalibrated for the kinematics parameters after 250 uses. The trocar and k-pin must be discarded after a single use.</li>
</ol>
4. Pedicle preparation and screw insertion
<ol>
	<li>Activate the drill function of the handpiece, and drill the instruments mounted on the front end (including K-pin: &#934; = 1.8 mm and trocar: &#934; = 5 mm) into the patient&#39;s body along the planned path.</li>
	<li>Use the c-arm to confirm the position of k-pin and trocar.</li>
	<li>If the k-pin and trocar positions are not correct under fluoroscopy, remove the k-pin and trocar. Then, using the handpiece, drill into the pedicle again until the k-pin and trocar insert into prone positions under fluoroscopy (refer to 4.3.1-4.3.2).
	<ol>
		<li>Under AP view, determine whether the instrument is located in the oval area formed by the pedicle in the perspective image.</li>
		<li>Under LAT view, determine whether the instrument is within the range of the pedicle and vertebra.</li>
	</ol>
	</li>
	<li>Replace K-pin and trocar with guidewires (&#934; = 1.5 mm, L = 400 mm) once the positions are appropriate.</li>
	<li>Insert the pedicle screw through the guidewires.</li>
	<li>Repeat steps 4.1&#8211;4.4 to complete all surgical planning paths. 
	NOTE: As for postoperative management, patients should be monitored in the post-anesthesia recovery unit (PACU) and the post-operative analgesia options should be selected. The basic PACU events, such as nausea, pain, hypotension, hypertension, and hypoxia, should be evaluated. Additionally, the staff should recognize when the patient meets the criteria for PACU discharge.</li>
</ol>

<ol>
	<li>Verma, K., Boniello, A., Rihn, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emerging+techniques+for+posterior+fixation+of+the+lumbar+spine.">Emerging techniques for posterior fixation of the lumbar spine.</a> Journal of the American Academy of Orthopaedic Surgery. 24 (6), 357-364 (2016).</li><li>Gaines, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+pedicle-screw+internal+fixation+for+the+operative+treatment+of+spinal+disorders.">The use of pedicle-screw internal fixation for the operative treatment of spinal disorders.</a> The Journal of Bone and Joint Surgery-American. 82 (10), 1458-1476 (2000).</li><li>Dede, O., Ward, W., Bosch, P., Bowles, A., Roach, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+the+freehand+pedicle+screw+placement+technique+in+adolescent+idiopathic+scoliosis+surgery:+what+is+the+incidence+of+neurological+symptoms+secondary+to+misplaced+screws.">Using the freehand pedicle screw placement technique in adolescent idiopathic scoliosis surgery: what is the incidence of neurological symptoms secondary to misplaced screws.</a> Spine. 39 (4), 286-290 (2014).</li><li>Costa, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Erratum:+Radiation+exposure+in+spine+surgery+using+an+image-guided+system+based+on+intraoperative+cone-beam+computed+tomography:+analysis+of+107+consecutive+cases.">Erratum: Radiation exposure in spine surgery using an image-guided system based on intraoperative cone-beam computed tomography: analysis of 107 consecutive cases.</a> Journal of Neurosurgery: Spine SPI. 26 (4), 542 (2017).</li><li>Stuer, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robotic+technology+in+spine+surgery:+Current+applications+and+future+developments.">Robotic technology in spine surgery: Current applications and future developments.</a> Intraoperative Imaging. 109, 241-245 (2011).</li><li>Devito, D. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+acceptance+and+accuracy+assessment+of+spinal+implants+guided+with+SpineAssist+surgical+robot:+retrospective+study.">Clinical acceptance and accuracy assessment of spinal implants guided with SpineAssist surgical robot: retrospective study.</a> Spine. 35 (24), 2109-2115 (2010).</li><li>Fan, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radiological+and+clinical+differences+among+three+assisted+technologies+in+pedicle+screw+fixation+of+adult+degenerative+scoliosis.">Radiological and clinical differences among three assisted technologies in pedicle screw fixation of adult degenerative scoliosis.</a> Scientific Reports. 8 (1), 890 (2018).</li><li>Kantelhardt, S. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perioperative+course+and+accuracy+of+screw+positioning+in+conventional,+open+robotic-guided+and+percutaneous+robotic-guided,+pedicle+screw+placement.">Perioperative course and accuracy of screw positioning in conventional, open robotic-guided and percutaneous robotic-guided, pedicle screw placement.</a> European Spine Joutnal. 20 (6), 860-868 (2011).</li><li>Verma, R., Krishnan, S., Haendlmayer, K., Mohsen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+outcome+of+computer-assisted+spinal+pedicle+screw+placement:+a+systematic+review+and+meta-analysis+of+23+studies+including+5,992+pedicle+screws.">Functional outcome of computer-assisted spinal pedicle screw placement: a systematic review and meta-analysis of 23 studies including 5,992 pedicle screws.</a> European Spine Journal. 19 (3), 370-375 (2010).</li><li>Ghasem, A., Sharma, A., Greif, D., Alam, M., Maaieh, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Arrival+of+Robotics+in+Spine+Surgery:+A+Review+of+the+Literature.">The Arrival of Robotics in Spine Surgery: A Review of the Literature.</a> Spine. 43 (23), 1670-1677 (2018).</li><li>Roser, F., Tatagiba, M., Maier, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spinal+robotics:+current+applications+and+future+perspectives.">Spinal robotics: current applications and future perspectives.</a> Neurosurgery. 72 (1), 12-18 (2013).</li><li>Chen, H. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Results+of+using+robotic-assisted+navigational+system+in+pedicle+screw+placement.">Results of using robotic-assisted navigational system in pedicle screw placement.</a> PLoS One. 14 (8), 0220851 (2019).</li><li>. NDI Medical Available from: <a target="_blank" href="https://www.ndigital.com/medical/products/polaris-vega">https://www.ndigital.com/medical/products/polaris-vega</a> (2020)</li><li>Gertzbein, S. D., Robbins, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+pedicular+screw+placement+in+vivo.">Accuracy of pedicular screw placement in vivo.</a> Spine. 15 (1), 11-14 (1990).</li><li>Kim, T. T., Johnson, J. P., Pashman, R., Drazin, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimally+Invasive+Spinal+Surgery+with+Intraoperative+Image-Guided+Navigation.">Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation.</a> Biomed Research International. 2016, 5716235 (2016).</li><li>Bailey, S. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+BWM+spinal+fixator+system.+A+preliminary+report+of+a+2-year+prospective,+international+multicenter+study+in+a+range+of+indications+requiring+surgical+intervention+for+bone+grafting+and+pedicle+screw+fixation.">The BWM spinal fixator system. A preliminary report of a 2-year prospective, international multicenter study in a range of indications requiring surgical intervention for bone grafting and pedicle screw fixation.</a> Spine. 21 (17), 2006-2015 (1996).</li><li>Lonstein, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complications+associated+with+pedicle+screws.">Complications associated with pedicle screws.</a> The Journal of Bone and Joint Surgery-American Volume. 81 (11), 1519-1528 (1999).</li></ol>

Point Robotics MedTech Inc employed authors Xiu-Yun Xiao, Chih-Wei Chen, Hao-Kai Chou, and Chen-Yu Sung. This study was partially supported by Point Robotics MedTech Inc., which provided the robot system. The authors declare that the point spine navigation system (PSNS) assessed in this study is a product in development.

Since 1990, there have been rapid developments in surgical applications involving the use of robots. The available robotic technologies have been optimized, resulting in improved accuracy, overcoming the tremor in human hands, and reduced matching and registration times of navigation systems15. The benefits of surgical robot assistance include: (1) immediate standardization without lengthy learning processes; (2) surgeons can precisely follow the pre-operative plan, which is superimposed on a CT-b...

In the field of spinal surgery, spinal fusion surgery is a fundamental surgical procedure, especially posterior pedicle screw fixation, which can provide three-column support of the vertebrae and enhance the strength of biomechanics; thus, it has become one of the most commonly used surgical procedures1. In many early studies, the clinical effect of posterior pedicle screw implantation has been confirmed, and it has been widely used in surgery for many different spinal disorders, such as degenerative, traumatic, and complicated spinal conditions2.
However, although the posterior lumbar spinal fusion surgery can achieve excellent treatment effects, it is still risky due to the human body anatomy. There are many vital tissue structures close to the pedicle, such as the central nervous system, nerve roots, and main blood vessels. The damage of these tissues during the surgical procedure may cause serious complications, such as vascular injuries, neurological deficits, or screw loosening2,3. Moreover, the surgeons and staff are exposed to additional radiation, particularly in the case of minimally invasive spinal procedures4. Surgeons may experience fatigue and hand tremors after lengthy and tedious spinal surgery procedures, such as screw placements, bone osteotomy, and nerve decompression5.
The unsatisfactory rate of the pedicle screw placement procedure necessitated the proposal for a robotic-assisted navigation system to be applied in spinal surgeries to improve the surgery accuracy and patients&#8217; safety. Several studies on robotic-assisted navigation systems have demonstrated improvements in the safety, accuracy, and precision of pedicle screw placement, as well as decreased radiation exposure and operative times6,7,8,9,10. However, thorough screw trajectory planning, pre-operative planning with images, comprehensive robotic system with fixation device, and robot control software still need to be addressed to achieve this goal. This study focuses on the description of the robotic structure and the workflow of a self-developed navigation system (i.e., the Point spine navigation system (PSNS)) for robotic-assisted pedicle screw placement surgeries.
System description and surgical protocol 
The PSNS comprises a navigation workstation that includes the following. (1) There is a user interface software responsible for image reading through three-dimensional (3D) reconstruction, pre-operative planning, spatial kinematic relationship calculation, and registration. (2) The PSNS uses infrared optical guidance systems to track the spatial position of surgical robots and patients. The infrared optical guidance system contains the following components: (i) an optical tracker that actively emits infrared light and performs stereo positioning through a dual camera (Figure 1); (ii) a marker sphere whose surface has a reflective coating with reflective properties for precise tool tracking; and (iii) a tool with a dynamic reference frame (DRF) that comprises a base and four marker spheres. To avoid the identification failure of the tracking system, each device has a unique DRF design and cannot be shared with each other. The DRF used includes a base frame (BF) attached to the base of the handpiece to confirm the handpiece position, an end-effector frame (EF) attached to the end of the handpiece to confirm the handpiece position, a fiducial frame (FF) anchored on the patient&#8217;s bone to confirm the patient&#8217;s position, and a probe whose tip is used to confirm the target position in 3D space. (3) There is a handpiece comprising a six degrees of freedom (DOF) Stewart platform, with one end of the robot equipped with an operation tool used for drilling the screw path. The handpiece is a robotic-assisted navigation system that assists surgeons toward the accurate placement of implants, such as pedicle screws, or positioning of surgical tools during spinal surgery. The movement of the surgical target is tracked as the robot automatically compensates for the correct target. The robot is designed as a semi-active system that offers surgical tool guidance; however, the actual surgery is performed by surgeons. The operating principle and equipment are illustrated in Figure 2.
PSNS is indicated for procedures including but not limited to the following sample procedures: (i) open, minimally invasive, or percutaneous spinal surgery; (ii) spinal surgery site for thoracic, lumbar, or sacral vertebrae; (iii) posterior spinal fusion for trauma, degenerative stenosis disease, instability, spondylolisthesis, herniated disc, tumor, infection, or spinal deformity correction; (iv) placement of temporary or permanent devices, such as k-wires or needles, while performing vertebroplasty, or either transforaminal or interlaminar percutaneous endoscopic lumbar discectomy; and (iv) bone tumor excision, including the ablation of osteoid osteoma or tumor biopsy, in which the robot directed needles or guidewires to a given vertebral location. This procedure is contraindicated for those with an inability to tolerate anesthesia, surgical procedure, or when satisfactory navigation images have not been acquired.
Note that the operation staff, including neurosurgeons and orthopedic surgeons, must be licensed and trained in guiding courses. All procedures for operating the robot during surgery need to follow the recommended standardized procedures to avoid causing harm to the patient or surgeon. Surgeons must possess conventional surgical experience to ensure that it is possible to switch back to conventional surgical instruments and complete the surgery when it is determined that the navigation is inaccurate, based on the surgeons&#8217; anatomical knowledge.

<table>
	<tbody>
		<tr>
			<td>Dynamic reference frames</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>FF tool kit: 
			1.Connecting Rod 
			2.Combination clamps 
			3.Multi-pin clamps 
			4.Schanz screw 
			5.Spinous process clamp 
			6.Open wrench 
			7.Hexagonal wrench</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Handpiece</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Handpiece holder</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Handpiece stand</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>K-pin</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Optical tracker</td>
			<td>NDI</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Passive spheres</td>
			<td>NDI</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Probe</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile box</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile drape</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Trocar</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Workstation cart</td>
			<td>POINT</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

a spine robotic-assisted navigation system for pedicle screw placement

Pedicle screw implantation has excellent treatment effects and is often used by surgeons in spinal fusion surgery. However, due to the complexity of human body anatomy, this surgical procedure is difficult and challenging, especially in minimally invasive surgery or patients with congenital anomalies and kyphoscoliosis deformity. In addition to the abovementioned factors, the surgical experience and technique of the surgeon also affect the recovery rates and complications of the patients after the surgical operation. Therefore, accurately performing pedicle screw implantation has is a constant topic of common concern for surgeons and patients. In recent years, with the technological development, robot-assisted navigation systems have gradually become adopted. These robot-assisted navigation systems provide surgeons with complete preoperative planning before surgery. The system provides 3D reconstructed images of each vertebra, allowing surgeons to understand the patient&#39;s physiological characteristics more quickly. It also provides 2D images of sagittal, coronal, axial and oblique planes so that surgeons can accurately perform pedicle screw placement plan.
Previous studies have demonstrated the effectiveness of robot-assisted navigation systems for pedicle screw implantation procedures, including accuracy and safety assessments. This step-by-step protocol aims to outline a standardized surgical technique note for robotic-assisted pedicle screw placement.

The safety and accuracy of robotic-assisted pedicle screw placements have been addressed in several studies6,11. We match the vertebrae with pre-operative planning images under an optical tracking system in the proposed method. After determining the planned surgical path, this information was transferred to the handpiece through the handpiece control unit. The navigation system integrates the tracking information and displays it on the monitor during the surgery....

Watch this Scientific Journal Video about A Spine Robotic-Assisted Navigation System for Pedicle Screw Placement at JoVE.com

A Spine Robotic-Assisted Navigation System for Pedicle Screw Placement

This article presents a standardized surgical technique for robotic-assisted pedicle screw placement by using robotic-assisted navigational systems. We present a step-by-step protocol and describe the workflow and precautions of this procedure.

Pedicle screw implantation has excellent treatment effects and is often used by surgeons in spinal fusion surgery. However, due to the complexity of human ...

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Unit 1

The Axial Skeleton

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8.7K Views.  National Taiwan University. This article presents a standardized surgical technique for robotic-assisted pedicle screw placement by using robotic-assisted navigational systems. We present a step-by-step protocol and describe the workflow and precautions of this procedure.

Video: A Spine Robotic-Assisted Navigation System for Pedicle Screw Placement

A Method for Ovarian Follicle Encapsulation and Culture in a Proteolytically Degradable 3 Dimensional System

The ovarian follicle is the functional unit of the ovary that secretes sex hormones and supports oocyte maturation. In vitro follicle techniques provide a tool to model follicle development in order to investigate basic biology, and are further being developed as a technique to preserve fertility in the clinic1-4. Our in vitro culture system employs hydrogels in order to mimic the native ovarian environment by maintaining the 3D follicular architecture, cell-cell interactions and paracrine signaling that direct follicle development 5. Previously, follicles were successfully cultured in alginate, an inert algae-derived polysaccharide that undergoes gelation with calcium ions6-8. Alginate hydrogels formed at a concentration of 0.25% w/v were the most permissive for follicle culture, and retained the highest developmental competence 9. Alginate hydrogels are not degradable, thus an increase in the follicle diameter results in a compressive force on the follicle that can impact follicle growth10. We subsequently developed a culture system based on a fibrin-alginate interpenetrating network (FA-IPN), in which a mixture of fibrin and alginate are gelled simultaneously. This combination provides a dynamic mechanical environment because both components contribute to matrix rigidity initially; however, proteases secreted by the growing follicle degrade fibrin in the matrix leaving only alginate to provide support. With the IPN, the alginate content can be reduced below 0.25%, which is not possible with alginate alone 5. Thus, as the follicle expands, it will experience a reduced compressive force due to the reduced solids content. Herein, we describe an encapsulation method and an in vitro culture system for ovarian follicles within a FA-IPN. The dynamic mechanical environment mimics the natural ovarian environment in which small follicles reside in a rigid cortex and move to a more permissive medulla as they increase in size11. The degradable component may be particularly critical for clinical translation in order to support the greater than 106-fold increase in volume that human follicles normally undergo in vivo .

A new method for ovarian follicle encapsulation in a 3D fibrin-alginate interpenetrating network is described. This system combines structural support with proteolytic degradation to support the development of immature follicles to produce mature oocytes. This method may be applied to culture cell aggregates to maintain cell-cell contacts without limiting expansion.

The ovarian follicle is the functional unit of the ovary that secretes sex hormones and supports oocyte maturation. In vitro  follicle techniques provide ...

Bacterial Detection &amp; Identification Using Electrochemical Sensors

Electrochemical sensors are widely used for rapid and accurate measurement of blood glucose and can be adapted for detection of a wide variety of analytes. Electrochemical sensors operate by transducing a biological recognition event into a useful electrical signal. Signal transduction occurs by coupling the activity of a redox enzyme to an amperometric electrode. Sensor specificity is either an inherent characteristic of the enzyme, glucose oxidase in the case of a glucose sensor, or a product of linkage between the enzyme and an antibody or probe.
Here, we describe an electrochemical sensor assay method to directly detect and identify bacteria. In every case, the probes described here are DNA oligonucleotides. This method is based on sandwich hybridization of capture and detector probes with target ribosomal RNA (rRNA). The capture probe is anchored to the sensor surface, while the detector probe is linked to horseradish peroxidase (HRP). When a substrate such as 3,3',5,5'-tetramethylbenzidine (TMB) is added to an electrode with capture-target-detector complexes bound to its surface, the substrate is oxidized by HRP and reduced by the working electrode. This redox cycle results in shuttling of electrons by the substrate from the electrode to HRP, producing current flow in the electrode.

Bacterial Detection & Identification Using Electrochemical Sensors

We describe an electrochemical sensor assay method for rapid bacterial detection and identification. The assay involves a sensor array functionalized with DNA oligonucleotide capture probes for ribosomal RNA (rRNA) species-specific sequences. Sandwich hybridization of target rRNA with the capture probe and a horseradish peroxidase-linked DNA oligonucleotide detector probe produces a measurable amperometric current.

Electrochemical  sensors are widely used for rapid and accurate measurement of blood glucose and  can be adapted for detection of a wide variety of ...

Skin Tattooing As A Novel Approach For DNA Vaccine Delivery

Nucleic acid-based vaccination is a topic of growing interest, especially plasmid DNA (pDNA) encoding immunologically important antigens. After the engineered pDNA is administered to the vaccines, it is transcribed and translated into immunogen proteins that can elicit responses from the immune system. Many ways of delivering DNA vaccines have been investigated; however each delivery route has its own advantages and pitfalls. Skin tattooing is a novel technique that is safe, cost-effective, and convenient. In addition, the punctures inflicted by the needle could also serve as a potent adjuvant. Here, we a) demonstrate the intradermal delivery of plasmid DNA encoding enhanced green fluorescent protein (pCX-EGFP) in a mouse model using a tattooing device and b) confirm the effective expression of EGFP in the skin cells using confocal microscopy.

Skin tattooing is a potent and safe way to delivery DNA vaccine intradermally. Here, a DNA plasmid encoding EGFP is delivered by tattooing to the skin of a laboratory mouse, and the expression of EGFP in the skin cells is then inspected by confocal microscopy.

Nucleic acid-based vaccination is a topic of growing interest, especially plasmid DNA (pDNA) encoding immunologically important antigens. After the ...

Membrane-SPINE: A Biochemical Tool to Identify Protein-protein Interactions of Membrane Proteins In Vivo

Membrane proteins are essential for cell viability and are therefore important therapeutic targets1-3. Since they function in complexes4, methods to identify and characterize their interactions are necessary5. To this end, we developed the Membrane Strep-protein interaction experiment, called Membrane-SPINE6. This technique combines in vivo cross-linking using the reversible cross-linker formaldehyde with affinity purification of a Strep-tagged membrane bait protein. During the procedure, cross-linked prey proteins are co-purified with the membrane bait protein and subsequently separated by boiling. Hence, two major tasks can be executed when analyzing protein-protein interactions (PPIs) of membrane proteins using Membrane-SPINE: first, the confirmation of a proposed interaction partner by immunoblotting, and second, the identification of new interaction partners by mass spectrometry analysis. Moreover, even low affinity, transient PPIs are detectable by this technique. Finally, Membrane-SPINE is adaptable to almost any cell type, making it applicable as a powerful screening tool to identify PPIs of membrane proteins.

Membrane-SPINE: A Biochemical Tool to Identify Protein-protein Interactions of Membrane Proteins In Vivo

A biochemical approach is described to identify in vivo protein-protein interactions (PPI) of membrane proteins. The method combines protein cross-linking, affinity purification and mass spectrometry, and is adaptable to almost any cell type or organism. With this approach, even the identification of transient PPIs becomes possible.

Membrane proteins are essential for cell viability and are therefore important therapeutic targets1-3. Since they function in complexes4, methods to ...

Cultivation of Mammalian Cells Using a Single-use Pneumatic Bioreactor System

Recent advances in mammalian, insect, and stem cell cultivation and scale-up have created tremendous opportunities for new therapeutics and personalized medicine innovations. However, translating these advances into therapeutic applications will require in vitro systems that allow for robust, flexible, and cost effective bioreactor systems. There are several bioreactor systems currently utilized in research and commercial settings; however, many of these systems are not optimal for establishing, expanding, and monitoring the growth of different cell types. The culture parameters most challenging to control in these systems include, minimizing hydrodynamic shear, preventing nutrient gradient formation, establishing uniform culture medium aeration, preventing microbial contamination, and monitoring and adjusting culture conditions in real-time. Using a pneumatic single-use bioreactor system, we demonstrate the assembly and operation of this novel bioreactor for mammalian cells grown on micro-carriers. This bioreactor system eliminates many of the challenges associated with currently available systems by minimizing hydrodynamic shear and nutrient gradient formation, and allowing for uniform culture medium aeration. Moreover, the bioreactor&#8217;s software allows for remote real-time monitoring and adjusting of the bioreactor run parameters. This bioreactor system also has tremendous potential for scale-up of adherent and suspension mammalian cells for production of a variety therapeutic proteins, monoclonal antibodies, stem cells, biosimilars, and vaccines.

Using a pneumatic bioreactor, we demonstrate the assembly, operation, and performance of this single-use bioreactor system for the growth of mammalian cells.

Recent advances in mammalian, insect, and stem cell cultivation and scale-up have created tremendous opportunities for new therapeutics and personalized ...

Gradient Strain Chip for Stimulating Cellular Behaviors in Cell-laden Hydrogel

Artificial guidance for cellular alignment is a hot topic in the field of tissue engineering. Most of the previous research has investigated single strain-induced cellular alignment on a cell-laden hydrogel by using complex experimental processes and mass controlling systems, which are usually associated with contamination issues. Thus, in this article, we propose a simple approach to building a gradient static strain using a fluidic chip with a plastic PDMS cover and a UV transparent glass substrate for the stimulation of cellular behavior in a 3D hydrogel. Overloading photo-patternable cell prepolymer in the fluidic chamber can generate a convex curved PDMS membrane on the cover. After UV crosslinking, through a concentric circular micropattern under the curved PDMS membrane, and buffer washing, a microenvironment for investigating cell behaviors under a variety of gradient strains is self-established in a single fluidic chip, without external instruments. NIH3T3 cells were demonstrated after observing the change in the cellular alignment trend under geometry guidance, in cooperation with strain stimulation, which varied from 15 - 65% on hydrogels. After a 3-day incubation, the hydrogel geometry dominated the cell alignment under low compressive strain, where cells aligned along the hydrogel elongation direction under high compressive strain. Between these, the cells showed random alignment due to the dissipation of the radical guidance of hydrogel elongation and the geometry guidance of the patterned hydrogel.

This article introduces a simple approach to providing non-continuous gradient static strains on a concentric cell-laden hydrogel to regulate cell alignment for tissue engineering.

Artificial guidance for cellular alignment is a hot topic in the field of tissue engineering. Most of the previous research has investigated single ...

Fast Pyrolysis of Biomass Residues in a Twin-screw Mixing Reactor

Fast pyrolysis is being increasingly applied in commercial plants worldwide. They run exclusively on woody biomass, which has favorable properties for conversion with fast pyrolysis. In order to increase the synergies of food production and the energetic and/or material use of biomass, it is desirable to utilize residues from agricultural production, e.g., straw. The presented method is suitable for converting such a material on an industrial scale. The main features are presented and an example of mass balances from the conversion of several biomass residues is given. After conversion, fractionated condensation is applied in order to retrieve two condensates &#8212; an organic-rich and an aqueous-rich one. This design prevents the production of fast pyrolysis bio-oil that exhibits phase separation. A two phase bio-oil is to be expected because of the typically high ash content of straw biomass, which promotes the production of water of reaction during conversion.
Both fractionated condensation and the use of biomass with high ash content demand a careful approach for establishing balances. Not all kind of balances are both meaningful and comparable to other results from the literature. Different balancing methods are presented, and the information that can be derived from them is discussed.

A procedure for thermochemical conversion of biomass residues is presented that aims at maximizing the yield of liquid products (fast pyrolysis). It is based on a technology proven on an industrial scale and especially suitable for treating a straw type of biomass.

Fast pyrolysis is being increasingly applied in commercial plants worldwide. They run exclusively on woody biomass, which has favorable properties for ...

Fabrication and Validation of an Organ-on-chip System with Integrated Electrodes to Directly Quantify Transendothelial Electrical Resistance

Organs-on-chips, in vitro models involving the culture of (human) tissues inside microfluidic devices, are rapidly emerging and promise to provide useful research tools for studying human health and disease. To characterize the barrier function of cell layers cultured inside organ-on-chip devices, often transendothelial or transepithelial electrical resistance (TEER) is measured. To this end, electrodes are usually integrated into the chip by micromachining methods to provide more stable measurements than is achieved with manual insertion of electrodes into the inlets of the chip. However, these electrodes frequently hamper visual inspection of the studied cell layer or require expensive cleanroom processes for fabrication. To overcome these limitations, the device described here contains four easily integrated electrodes that are placed and fixed outside of the culture area, making visual inspection possible. Using these four electrodes the resistance of six measurement paths can be quantified, from which the TEER can be directly isolated, independent of the resistance of culture medium-filled microchannels. The blood-brain barrier was replicated in this device and its TEER was monitored to show the device applicability. This chip, the integrated electrodes and the TEER determination method are generally applicable in organs-on-chips, both to mimic other organs or to be incorporated into existing organ-on-chip systems.

This publication describes the fabrication of an organ-on-chip device with integrated electrodes for direct quantification of transendothelial electrical resistance (TEER). For validation, the blood-brain barrier was mimicked inside this microfluidic device and its barrier function was monitored. The presented methods for electrode integration and direct TEER quantification are generally applicable.

Organs-on-chips, in vitro models involving the culture of (human) tissues inside microfluidic devices, are rapidly emerging and promise to provide useful ...

A Millimeter Scale Flexural Testing System for Measuring the Mechanical Properties of Marine Sponge Spicules

Many load bearing biological structures (LBBSs)&#8212;such as feather rachises and spicules&#8212;are small (&#60;1 mm) but not microscopic. Measuring the flexural behavior of these LBBSs is important for understanding the origins of their remarkable mechanical functions.
We describe a protocol for performing three-point bending tests using a custom-built mechanical testing device that can measure forces ranging from 10-5 to 101 N and displacements ranging from 10-7 to 10-2 m. The primary advantage of this mechanical testing device is that the force and displacement capacities can be easily adjusted for different LBBSs. The device&#39;s operating principle is similar to that of an atomic force microscope. Namely, force is applied to the LBBS by a load point that is attached to the end of a cantilever. The load point displacement is measured by a fiber optic displacement sensor and converted into a force using the measured cantilever stiffness. The device&#39;s force range can be adjusted by using cantilevers of different stiffnesses.
The device&#39;s capabilities are demonstrated by performing three-point bending tests on the skeletal elements of the marine sponge Euplectella aspergillum. The skeletal elements&#8212;known as spicules&#8212;are silica fibers that are approximately 50 &#181;m in diameter. We describe the procedures for calibrating the mechanical testing device, mounting the spicules on a three-point bending fixture with a &#8776;1.3 mm span, and performing a bending test. The force applied to the spicule and its deflection at the location of the applied force are measured.

We present a protocol for performing three-point bending tests on sub-millimeter scale fibers using a custom-built mechanical testing device. The device can measure forces ranging from 20 &#181;N up to 10 N and can therefore accommodate a variety of fiber sizes.

Many load bearing biological structures (LBBSs)&#8212;such as feather rachises and spicules&#8212;are small (&#60;1 mm) but not microscopic. Measuring the ...

Construction of a Multilayered Mesenchymal Stem Cell Sheet with a 3D Dynamic Culture System

Stem cell therapy shows a promising future in regenerating injured organ and tissues, and the cell sheet technique has been developed to improve the low cell retention and poor survival within the target zone. However, during the in vitro construction process, a solution for maintaining stem cell bioactivity and increasing the cell amount within the cell sheet is urgently needed. Here, this protocol presents a method for constructing a multilayered cell sheet with favorable stem cell bioactivity and optimal operability. Decellularized porcine pericardium (DPP) is prepared by phospholipase A2 (PLA2) decellularization method as the cell sheet scaffold, and rat bone marrow mesenchymal stem cells (BMSCs) are isolated and expanded as the seeded cells. The temporary multilayered cell sheet structure is constructed by using RAD16-I peptide hydrogel. Finally, the cell sheet is cultured with a dynamic perfusion system to stabilize the three-dimensional (3D) structure, and the cell sheet could be obtained following a 48-hour culture in vitro. This protocol provides an efficient and feasible method for constructing a multilayered stem cell sheet, and the cell sheet could be developed as a favorable stem cell therapy product in the future.

This article provides an efficient and feasible method for constructing multilayered stem cell sheets with favorable stem cell property.

Stem cell therapy shows a promising future in regenerating injured organ and tissues, and the cell sheet technique has been developed to improve the low ...

A Spine Robotic-Assisted Navigation System for Pedicle Screw Placement

Summary

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Chapters in this video

A Method for Ovarian Follicle Encapsulation and Culture in a Proteolytically Degradable 3 Dimensional System

Bacterial Detection & Identification Using Electrochemical Sensors

Skin Tattooing As A Novel Approach For DNA Vaccine Delivery

Membrane-SPINE: A Biochemical Tool to Identify Protein-protein Interactions of Membrane Proteins In Vivo

Cultivation of Mammalian Cells Using a Single-use Pneumatic Bioreactor System

Gradient Strain Chip for Stimulating Cellular Behaviors in Cell-laden Hydrogel

Fast Pyrolysis of Biomass Residues in a Twin-screw Mixing Reactor

Fabrication and Validation of an Organ-on-chip System with Integrated Electrodes to Directly Quantify Transendothelial Electrical Resistance

A Millimeter Scale Flexural Testing System for Measuring the Mechanical Properties of Marine Sponge Spicules

Construction of a Multilayered Mesenchymal Stem Cell Sheet with a 3D Dynamic Culture System