The authors have no acknowledgements.

The protocol illustrated here follows the guidelines of the human research ethics committee at Brigham and Women&#39;s Hospital.
1. Preoperative Protocol
<ol>
	<li>Assess patients with spinal pathology in clinic and determine eligibility for spinal surgery. Perform neurological assessment and obtain CT or MRI scan to identify spinal lesion.</li>
	<li>Include patients who have an intradural pathology such as schwannoma, ependymoma, meningioma, astrocytoma, etc.; or patients who have a ventral compressive extradural pathology, such as a ventral thoracic herniated disc, fracture fragments ventrally, or a spinal bony tumor with ventral compression. 
	NOTE: Pathology is determined by spinal imaging with CT or MRI. Exclusion criteria includes the patients who cannot tolerate surgery, or patients with an extremely poor prognosis.</li>
</ol>
2. Preparation for Surgery
<ol>
	<li>Do not allow the patient to consume anything by mouth after the midnight before surgery. 
	NOTE: The patient will be placed under general anesthesia and intubated by the anesthesiologist.</li>
	<li>Position patient with their back exposed according to surgeon&#39;s preference for the spinal surgery.</li>
	<li>Sterilize the surgical area with povidone-iodine by scrubbing the area.</li>
</ol>
3. Surgery
Note: This section of the protocol follows general spine surgery techniques that can be referenced from any reputable spine surgery technique textbook19.
<ol>
	<li>Make an incision with a scalpel along the length of the spine over the appropriate vertebrae levels and continue to make a straight incision down until the bone is reached. 
	NOTE: The size of the incision will depend on the size of the pathology. For example, if the tumor spans two vertebral levels, then at least two vertebral levels will need to be exposed. When the bone is exposed, an X-ray with a portable X-ray machine can be performed to verify the correct vertebrae.</li>
	<li>Perform subperiosteal dissection by electrosurgical cautery and expose the spinous process which is visualized as a bulbous bony process. Turn the cutting edge ventrally and sweep across the laminar.</li>
	<li>Use a combination of a Leksell bone plier and a highspeed drill to remove the bony lamina and spinous process to expose the ligamentum flavum underneath.</li>
	<li>Use an angled Curette and Kerrison bone punch to remove the ligamentum flavum to reveal the dura mater underneath.</li>
	<li>Use bipolar and hemostatic matrix to achieve hemostasis. 
	NOTE: The success of a good ultrasound image relies upon a clean surgical field.</li>
</ol>
4. Intraoperative Ultrasound
<ol>
	<li>Use a mobile ultrasound machine and a transducer probe with a 20 mm diameter. 
	NOTE: The probe should have a 10 to 4.4 MHz frequency range. Any comparable device with similar probe diameter and frequency range should suffice.</li>
	<li>After the bony removal and dura exposure, fill the surgical field with sufficient saline solution such that the ultrasound transducer probe can be submerged. 
	NOTE: Generally, a range of 100-500 mL of saline solution is needed. The saline solution allows for acoustic coupling.</li>
	<li>Turn on the ultrasound machine and place the ultrasound probe within the saline bath at the level of interest to begin acquiring images. 
	NOTE: It is not necessary to place the probe directly touching the dura or spinal cord. Images are acquired on the ultrasound screen in real-time and can be interpreted immediately by the surgeon. Images on the screen can be captured at any time by pressing the Freeze button and can be saved by pressing the Save button.</li>
	<li>Acquire real time images in the longitudinal plane by placing the ultrasound probe in line with the direction of the spinal canal to visualize the spinal cord and the lesion similar to the sagittal images from the MRI.</li>
	<li>Acquire real time images in the transverse plane by placing the ultrasound probe perpendicular to the spinal canal to visualize the spinal cord and the lesion like the axial images from the MRI.</li>
	<li>Acquire real-time images to verify the location of lesions that cannot be directly visualized, to correlate with the preoperative CT or MRI images, to guide surgical tool placement, and/or to confirm the resolution of pathology. 
	NOTE: When needed, a small piece of sterile compressed sponge approximately 0.5 cm x 0.5 cm can be used as a hyperechoic surgical marker to be placed in the surgical field and help correlate the surgical location with the image location. This helps to locate the lesion during the surgery and also helps to identify the margin of the tumor.</li>
</ol>
5. Postoperative Follow-up
<ol>
	<li>After discharge, have the patient return to the clinic within one month for follow-up.</li>
	<li>Perform a neurological assessment and CT or MRI scans to confirm the resolution of the symptoms and pathology.</li>
</ol>

<ol>
	<li>Reid, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasonic+visualization+of+a+cervical+cord+cystic+astrocytoma.">Ultrasonic visualization of a cervical cord cystic astrocytoma.</a> AJR. American Journal of Roentgenology. 131 (5), 907-908 (1978).</li><li>Dohrmann, G. J., Rubin, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraoperative+ultrasound+imaging+of+the+spinal+cord:+syringomyelia,+cysts,+and+tumors--a+preliminary+report.">Intraoperative ultrasound imaging of the spinal cord: syringomyelia, cysts, and tumors--a preliminary report.</a> Surgical Neurology. 18 (6), 395-399 (1982).</li><li>Rubin, J. M., Dohrmann, G. 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The authors have nothing to disclose.

Intraoperative ultrasound in the spinal surgery has largely fallen out of favor with the advent of newer technology, however, it continues to provide several advantages over the other available imaging modalities such as MRI and CT6,9,16,17,18. In addition to being inexpensive, in this protocol we also show that it is simple to use and can provide visualization of structures with adequate resolution that could otherwise not be directly seen by the surgeon. It is particularly useful in cases where the surgeon is approaching a lesion located ventrally to the spinal canal in a posterior manner. Additionally, the images can be correlated with pre-operative MRI or CT images and do not require a radiologist for interpretation. Most importantly, intraoperative ultrasound remains the only imaging modality that allows for real-time image acquisition36. Ultrasound also poses no radiation risk to the patient or surgeon.
Preoperative MRI or CT images should be analyzed carefully to avoid intraoperative complications and to accurately determine the location of the initial incision. This will help ensure that the ultrasound probe will be at the precise location desired. After the initial incision is made, an X-ray can be performed intraoperatively at the incision site to confirm vertebrae location. It is critical that sufficient hemostasis is reached prior to filling the surgical field with saline to acquire clear images as blood can attenuate ultrasound waves. It is not necessary for the probe to directly touch the dura or spinal cord for images acquisition. If images are not clear upon acquisition, drain the saline solution and fill with fresh saline solution and repeat image acquisition.
The only limitations to this protocol is that it is operator dependent, however the learning curve is gentle and surgeons can become proficient after the first or second operation36.
In conclusion, intraoperative ultrasound is useful in spinal surgery and should be considered especially in cases of intradural lesions and lesions ventral to the thecal sac when approaching posteriorly. Recent introduction of contrast-enhanced ultrasound has demonstrated potential use as well, in spinal Dural arteriovenous fistulas and vascularized spinal tumors37,38. Education and the use of intraoperative ultrasound in spinal surgery should also be incorporated into residency and fellowship teaching programs. Future development in the ultrasound technology can further enhance and increase the utility of this imaging modality.

Ultrasound is one of the most common diagnostic tools in medicine, particularly for visualizing pathology in the abdomen, limbs, and neck. However, its use to investigate cranial and spinal lesions is not currently widely utilized. In 1978, Reid was the first to report the use of ultrasound to visualize cervical cord cystic astrocytoma1. Here, scans were performed with the patient&#39;s neck flexed to allow opening of the intralaminar window. Four years later, in 1982, Dohrmann and Rubin reported the use of ultrasound intraoperatively to visualize the intradural space in 10 patients2. Pathologies identified with intraoperative ultrasound among the 10 patients included syringomyelia, spinal cord cysts, and intramedullary and extramedullary tumors. They further demonstrated the use of intraoperative ultrasound to guide catheters and probes for biopsy of tumors, drainage of cysts, and ventricular shunt catheter placement3. This allowed the real-time monitoring and precise positioning of probes/catheters, reducing inaccuracy and errors in placement. Following these initial reports, several others have published the use of intraoperative ultrasound for guiding spinal cord cyst drainage, intramedullary and extramedullary tumor resection, and syringo-subarachnoid shunt catheter placement4,5,6,7,8,9,10. Additionally, it has been shown to also increase rate of complete resection of intra-axial solid brain tumors and spinal intradural tumors11,12. Intraoperative ultrasound has also proven to be useful for the intraoperative surgical planning before manipulation of the tissue and subsequent visualization of adequate neural element decompression in patients with spine fractures7,9,13,14,15.
With the advent of newer intraoperative technology allowing clearer visualization of soft tissues, such as magnetic resonance imaging (MRI) and computed tomography (CT), intraoperative ultrasound has become less common and a less favored intraoperative imaging modality among neurosurgeons today16. However, intraoperative ultrasound can have advantages over these newer technologies in certain operative cases (Table 1). Intraoperative ultrasound has shown to demonstrate better soft tissue visualization of intradural structures when compared with intraoperative CT (iCT) or cone-beam CT (cbCT)9,17. While intraoperative MRI (iMRI) is useful where available because of the higher soft tissue resolution it provides, it is costly, time consuming and does not provide real-time images6, 16,18. An example is in the circumstance of an intradural mass ventral to the thecal sac that the surgeon is unable to directly visualize. Additionally, despite being operator dependent, from our experience, intraoperative ultrasound is fairly simple to use and can be easily read without a radiologist.

<table><tbody><tr><td>Aloka Prosound 5 mobile ultrasound machine</td><td>Hitachi</td><td>N/A</td><td>any comparable devices on the market should suffice</td></tr><tr><td>UST-9120 transducer probe.</td><td>Hitachi</td><td>UST-9120</td><td>Has a 20mm diameter with 10 to 4.4 MHz frequency range (any comparable compatible transducer should suffice).</td></tr></tbody></table>

intraoperative ultrasound in spinal surgery

Since the 1980s, there have been several reports for the use of intraoperative ultrasound as a useful adjunct in spinal surgery. However, with the advent of newer cutting-edge imaging modalities, the use of intraoperative ultrasound in spine surgery has largely fallen out of favor. Despite this, intraoperative ultrasound continues to provide several advantages over other intraoperative techniques such as magnetic resonance imaging and computed tomography including being more cost-effective, efficient, and easy to operate and interpret. Additionally, it remains the only method for the real-time visualization of soft tissue and pathologies. This paper focuses on the advantages of using intraoperative ultrasound, especially in cases of intradural lesions and lesions ventral to the thecal sac when approaching posteriorly.

On normal spine ultrasound imaging, the dura is an echogenic layer that surrounds the anechoic spinal fluid. The spinal cord is distinguished by its homogenous appearance and low echogenicity which is surrounded by an echogenic rim. This echogenic rim is due to the density shift from the spinal fluid to the spinal cord. The central canal appears as a bright central echo, while exiting nerve roots appear highly echogenic, particularly at the cauda equina16. Intraoperative ultrasound can play an advantageous role in the intradural mass lesion resection. In a standard case, preoperative CT or MRI approximates the location of an intradural mass with respect to known adjacent structures. With this approximation, a durotomy is made, usually with the extension of the durotomy in either direction for sufficient exposure of the lesion. In cases of cauda equina tumors, the lesion can rostrally migrate with respect to preoperative imaging20. With intraoperative ultrasound, the lesion can be readily visualized prior to dural opening and durotomy can be made more appropriately and accurately to the exact location of the mass20,21. Furthermore, with intramedullary lesions where there is a need for dissection through the spinal cord to reach tumors, risk of neural damage and subsequent neurological deficit can be reduced with the use of intraoperative ultrasound to guide the surgeon22. Additionally, a sterile compressed sponge is easily identified on ultrasound a hyperechoic material without acoustic wave attenuation and can be utilized as a surgical marker to distinguish tissue planes and limits for dissection15,23. An example is seen in Figure&#160;1, 2 and 3 where a cervical intramedullary lesion was approached via a midline myelotomy. Intraoperative ultrasound was beneficial in visualizing and delineating tumor limits, as well as determining resection and resolution of tumor mass effect.
Intraoperative ultrasound is also particularly useful in operative cases with a posterior approach to resect lesions ventral to the thecal sac, especially in the cervical and thoracic spine where the spinal cord is vulnerable to injury with manipulation. While the ventral spinal canal can be approached anteriorly for better visualization of the lesion, there are associated increases in operative time, bleeding, and morbidity. Thus, a posterior approach is preferable, and inability to visualize the lesion directly can be overcome with intraoperative ultrasound to guide the surgeon. Cases where this technique is particularly useful include resection of intervertebral disc herniations, reduction of thoracolumbar burst fractures, resection of ventral extradural tumors, and in cases of spinal canal stenosis due to ossification of the posterior longitudinal ligament where confirmation of adequate posterior decompression is needed13, 14, 24,25,26,27,28,29,30,31,32,33,34. In a symptomatic thoracic disc herniation resection by posterior approach, intraoperative ultrasound aided in evaluating decompression and ensuring all compressive disc fragments were excised (Figure&#160;4-5). Similarly, in the case of a lumbar burst fracture, intraoperative ultrasound was useful in confirming adequate decompression and removal of all fragments (Figure&#160;6-7).
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Imaging technology</td>
			<td>Advantage</td>
		</tr>
		<tr>
			<td rowspan="2">Intraoperative ultrasound</td>
			<td>&#8226;&#160; Real-time</td>
		</tr>
		<tr>
			<td>&#8226;&#160;&#160;Excellent soft tissue resolution</td>
		</tr>
		<tr>
			<td rowspan="2">Cone beam CT and intraoperative CT</td>
			<td>&#8226;&#160;&#160;3D and multiplanar reconstructions</td>
		</tr>
		<tr>
			<td>&#8226;&#160;&#160;Able to be paired with navigation systems</td>
		</tr>
		<tr>
			<td rowspan="2">Intraoperative MRI</td>
			<td>&#8226;&#160;&#160;Multiplanar reconsutrctions</td>
		</tr>
		<tr>
			<td>&#8226;&#160;&#160;Excellent soft tissue resolution</td>
		</tr>
		<tr>
			<td rowspan="2">Intraoperative fluoroscopy</td>
			<td>&#8226;&#160;&#160;Real-time</td>
		</tr>
		<tr>
			<td>&#8226;&#160;&#160;2D images of bony structures</td>
		</tr>
	</tbody>
</table>
Table 1. Comparison of intraoperative imaging techniques
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58080/58080fig1.jpg" /> 
Figure 1. Preoperative images reveal an intramedullary lesion. A 54-year-old male with no significant past medical history presented with a 1-month history of fever.&#160;A cervical MRI revealed a C6 intramedullary lesion. The mass size did not change after 1 month and extensive workup did not reveal other possible causes of his fever. Patient was subsequently brought to the operating room for definitive diagnosis. (A) Sagittal T2-weighted MRI revealed an intramedullary lesion at C5-7 with fluid collection at the top of the mass. (B) Sagittal T1-weighted MRI. (C) Sagittal contrast-enhanced MRI shows scant rim enhancement. (D) Axial T2-weighted MRI at the level of the fluid collection. (E) Axial T2-weighted MRI of the lower part of the lesion. *This figure has been modified from Vasudeva et al.35. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58080/58080fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/58080/58080fig2.jpg" /> 
Figure 2. Intraoperative ultrasound of the spinal cord after laminectomy. Patient underwent a C5-7 laminectomy and subsequent resection of the intramedullary lesion.&#160;Intraoperative ultrasound was used to guide the surgical path through the spinal cord until the tumor could be visualized. (A) Intraoperative ultrasound correlated with preoperative MRI imaging, revealing fluid collection (white arrow). (B) Axial intraoperative ultrasound shows mass encompassing majority of the spinal cord. (C) A 0.5 cm x 0.5 cm piece of sterile compressed sponge (white arrow) was used during the operation to confirm the caudal limit of the tumor. (D) Intraoperative ultrasound post-resection confirming complete removal of tumor and resolution of mass effect. *This figure has been modified from Vasudeva et al.35. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58080/58080fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/58080/58080fig3.jpg" /> 
Figure 3. Post-operative resection imaging reveals complete tumor resection. Post-operatively, the patient returned to baseline and fever resolved. Pathology revealed grade II ependymoma. (A) Sagittal T2-weighted MRI 2 months post-operatively showing complete resection of the tumor. (B) T1-weighted MRI without contrast. (C, D) T1-weighted MRI with contrast. *This figure has been modified from Vasudeva et al.35. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58080/58080fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/58080/58080fig4v5.jpg" /> 
Figure 4. Preoperative MRI reveals severe spinal cord compression. A 73-year-old female presented with a history of several months of worsening gait dysfunction, spasticity, and numbness in her lower extremities. Motor strength was intact on neurological exam however she had marked clonus, 4+ lower extremity reflexes, and a wide-based staggering gait. CT and MRI revealed a large, noncalcified T10-11 intervertebral disc hernation with compression of the spinal cord. (A) Sagittal and (B) axial T2-weighted MRI revealing T10-11 disc herniation with spinal cord compression. *This figure has been modified from Vasudeva et al.35. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58080/58080fig4v5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/58080/58080fig5v5.jpg" /> 
Figure 5. Intraoperative ultrasound reveals disc herniation and spinal cord compression. Patient underwent a right-sided T10-11 hemilaminectomy, facetectomy, and pedicle-sparing microdiscectomy with T9-11 fusion. (A) Intraoperative ultrasound was used to accurately determine the location of the disc herniation, (B) and to evaluate decompression and ensure complete removal of the herniated disc. Patient returned to her neurological baseline postoperatively and her prior symptoms had resolved at her 1-month follow up. *This figure has been modified from Vasudeva et al.35. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58080/58080fig5v5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/58080/58080fig6v5.jpg" /> 
Figure 6. Preoperative CT demonstration pathological L2 burst fracture. A 57-year-old female with a history significant for metastatic appendiceal cancer and a balloon kyphoplasty at L1 and L2 a month prior for pathologic compression fractures presented with mechanical back pain and acute-onset of left anterior thigh pain. Motor strength was intact throughout, however she had decreased sensation to light touch over her left anterior thigh. (A) Sagittal and (B) axial CT revealed pathological L2 burst fracture. *This figure has been modified from Vasudeva et al.35. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58080/58080fig6v5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/58080/58080fig7v5.jpg" /> 
Figure 7. Intraoperative ultrasound reveals retropulsed bone fragment and subsequent complete reduction of fracture. Patient underwent an L1-L2 laminectomy, left transpedicular reduction of the fracture, and T12-L3 posterolateral fusion. Intraoperative ultrasound was used to identify any residual bone fragments. (A) A retropulsed bone fragment that was not directly visualized was seen in the ventral spinal canal displacing the thecal sac. (B) Complete reduction of the fracture and adequate decompression of the spinal canal was confirmed with ultrasound. Postoperatively, the patient returned to baseline with symptom resolution. *This figure has been modified from Vasudeva et al.35.&#160;<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58080/58080fig7v5large.jpg">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Intraoperative Ultrasound in Spinal Surgery at JoVE.com

Intraoperative Ultrasound in Spinal Surgery

Here, we present a protocol on the use of intraoperative ultrasound in spinal surgery, particularly in cases of intradural lesions and lesions in the ventral spinal canal when using a posterior approach.

Since the 1980s, there have been several reports for the use of intraoperative ultrasound as a useful adjunct in spinal surgery. However, with the advent ...

intraoperative-ultrasound-in-spinal-surgery

Nanyang Technological University

Research

JoVE Journal

Medicine

4.6K Views.  Harvard Medical School. Intraoperatieve echografie voor wervelkolomchirurgie is zeer nuttig voor intradurale pathologie of ventrale spinale pathologie waarmee de chirurg de laesie kan visualiseren voordat dura wordt geopend. Dit helpt de chirurg ook om te lokaliseren waar de laesie is en ook om de adequate decompressie van het ruggenmerg te bevestigen na de verwijdering van de laesie, tumorverwijdering. Het biedt de real-time informatie die zeer, zeer nuttig is voor de wervelkolomchirurg tijdens de zaak.Het b...

Video: Intraoperative Ultrasound in Spinal Surgery

In vivo Imaging of the Mouse Spinal Cord Using Two-photon Microscopy

In vivo imaging using two-photon microscopy 1 in mice that have been genetically engineered to express fluorescent proteins in specific cell types 2-3 has significantly broadened our knowledge of physiological and pathological processes in numerous tissues in vivo 4-7. In studies of the central nervous system (CNS), there has been a broad application of in vivo imaging in the brain, which has produced a plethora of novel and often unexpected findings about the behavior of cells such as neurons, astrocytes, microglia, under physiological or pathological conditions 8-17. However, mostly technical complications have limited the implementation of in vivo imaging in studies of the living mouse spinal cord. In particular, the anatomical proximity of the spinal cord to the lungs and heart generates significant movement artifact that makes imaging the living spinal cord a challenging task.
We developed a novel method that overcomes the inherent limitations of spinal cord imaging by stabilizing the spinal column, reducing respiratory-induced movements and thereby facilitating the use of two-photon microscopy to image the mouse spinal cord in vivo. This is achieved by combining a customized spinal stabilization device with a method of deep anesthesia, resulting in a significant reduction of respiratory-induced movements. This video protocol shows how to expose a small area of the living spinal cord that can be maintained under stable physiological conditions over extended periods of time by keeping tissue injury and bleeding to a minimum. Representative raw images acquired in vivo detail in high resolution the close relationship between microglia and the vasculature. A timelapse sequence shows the dynamic behavior of microglial processes in the living mouse spinal cord. Moreover, a continuous scan of the same z-frame demonstrates the outstanding stability that this method can achieve to generate stacks of images and/or timelapse movies that do not require image alignment post-acquisition. Finally, we show how this method can be used to revisit and reimage the same area of the spinal cord at later timepoints, allowing for longitudinal studies of ongoing physiological or pathological processes in vivo.

In vivo Imaging of the Mouse Spinal Cord Using Two-photon Microscopy

A minimally invasive protocol to stabilize the mouse spinal column and perform repetitive in vivo spinal cord imaging using two-photon microscopy is described. This method combines a spinal stabilization device and an anesthetic regimen to minimize respiratory-induced movements and produce raw imaging data that require no alignment or other post-processing.

In vivo imaging using two-photon microscopy 1 in mice that have been genetically engineered to express fluorescent proteins in specific cell types 2-3 has ...

Neuroscience

A Teleoperated Robotic System-Assisted Percutaneous Transiliac-Transsacral Screw Fixation Technique

Transiliac-transsacral screw fixation is challenging in clinical practice as the screws need to break through six layers of cortical bone. Transiliac-transsacral screws provide a longer lever arm to withstand the perpendicular vertical shear forces. However, the screw channel is so long that a minor discrepancy can lead to iatrogenic neurovascular injuries. The development of medical robots has improved the precision of surgery. The present protocol describes how to use a new teleoperated robotic system to execute transiliac-transacral screw fixation. The Robot was operated remotely to position the entry point and adjust the orientation of the sleeve. The screw positions were evaluated using postoperative computed tomography (CT). All the screws were safely implanted, as confirmed using intraoperative fluoroscopy. Postoperative CT confirmed that all the screws were in the cancellous bone. This system combines the doctor's initiative with the Robot's stability. The remote control of this procedure is possible. Robot-assisted surgery has a higher position-retention capacity compared with conventional methods. In contrast to active robotic systems, surgeons have full control over the operation. The robot system is fully compatible with operating room systems and does not require additional equipment.

Teleoperated robotic system-assisted percutaneous transiliac-transsacral screw fixation is a feasible technique. Screw channels can be implemented with high accuracy owing to the excellent freedom of movement and stability of the robotic arms.

Transiliac-transsacral screw fixation is challenging in clinical practice as the screws need to break through six layers of cortical bone. ...

Engineering

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.

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 ...

Bioengineering

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

Pedicle screw fixation is the gold standard for the treatment of spinal diseases. However, many studies have reported the issue of loosening pedicle screws after spinal surgery, which is a serious concern. To address this problem, diverse types of pedicle screws have been examined to identify those with good fixation strength and osseointegration in spine bone. The porcine spine is a good alternative for the human spine in the evaluation of pedicle screws due to the anatomical size, mechanical characteristics, and cost. Although several studies have reported that pedicle screws are efficient in the porcine model, no study has described detailed protocols for the evaluation of a pedicle screw using the porcine model. Here, we describe a detailed method for evaluating transpedicular screws using an in vivo porcine lumbar spine model. The technical details for anesthesia, spine surgery, and harvest provided here will facilitate with the evaluation of the transpedicular screw fixation model.

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

Here, we introduce a method to evaluate transpedicular screws by using an in vivo porcine lumbar spine model.

Pedicle screw fixation is the gold standard for the treatment of spinal diseases. However, many studies have reported the issue of loosening pedicle ...

Cone Beam Intraoperative Computed Tomography-based Image Guidance for Minimally Invasive Transforaminal Interbody Fusion

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) approaches have been applied to this technique with an associated decrease in estimated blood loss (EBL), length of hospital stay, and infection rates, while preserving outcomes with traditional open surgery. Previous MIS TLIF techniques involve significant fluoroscopy that subjects the patient, surgeon, and operating room staff to non-trivial levels of radiation exposure, particularly for complex multi-level procedures. We present a technique that utilizes an intraoperative computed tomography (CT) scan to aid in placement of pedicle screws, followed by traditional fluoroscopy for confirmation of cage placement. Patients are positioned in the standard fashion and a reference arc is placed in the posterior superior iliac spine (PSIS) followed by intraoperative CT scan. This allows for image-guidance-based placement of pedicle screws through a one-inch skin incision on each side. Unlike traditional MIS-TLIF that requires significant fluoroscopic imaging during this stage, the operation can now be performed without any additional radiation exposure to the patient or operating room staff. After completion of the facetectomy and discectomy, final TLIF cage placement is confirmed with fluoroscopy. This technique has the potential to decrease operative time and minimize total radiation exposure.

The purpose of this article is to provide image-guidance for minimally invasive transforaminal interbody fusion.

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. ...

C-arm-Free Simultaneous OLIF51 and Percutaneous Pedicle Screw Fixation in a Single Lateral Position

Oblique lumbar interbody fusion (OLIF) is an established technique for the indirect decompression of lumbar canal stenosis. However, OLIF at the L5-S1 level (OLIF51) is technically difficult because of the anatomical structures. We present a novel simultaneous technique of OLIF51 with percutaneous pedicle screw fixation without fluoroscopy. The patient is placed in a right lateral decubitus position. A percutaneous reference pin is inserted into the right sacroiliac joint. An O-arm scan is performed, and 3D reconstructed images are transmitted to the spinal navigation system. A 4 cm oblique skin incision is made under navigation guidance along the pelvis. The internal/external and transverse abdominal muscles are divided along the muscle fibers, protecting the iliohypogastric and ilioinguinal nerves. Using a retroperitoneal approach, the left common iliac vessels are identified. Special muscle retractors with illumination are used to expose the L5-S1 intervertebral disc. After disc preparation with navigated instruments, the disc space is distracted with navigated trials. Autogenous bone and demineralized bone material are then inserted into the cage hole. The OLIF51 cage is inserted into the disc space with the help of a mallet. Simultaneously, percutaneous pedicle screws are inserted by another surgeon without changing the lateral decubitus position of the patient.
In conclusion, C-arm-free OLIF51 and simultaneous percutaneous pedicle screw fixation are performed in a lateral position under navigation guidance. This novel technique reduces surgical time and radiation hazards.

C-arm-free oblique lumbar interbody fusion at the L5-S1 level (OLIF51) and simultaneous pedicle screw fixation are performed in a lateral position under navigation guidance. This technique does not expose the surgeon or operating staff to radiation hazards.

Oblique lumbar interbody fusion (OLIF) is an established technique for the indirect decompression of lumbar canal stenosis. However, OLIF at the L5-S1 ...

Clinical Application of Microscope-Assisted Minimally Invasive Anterior Lumbar Interbody Fusion

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for minimally invasive anterior lumbar interbody fusion (Mini-ALIF). This article is a technical description of anterior lumbar spine surgery under a microscope. We retrospectively collected information on patients who underwent microscope-assisted Mini-ALIF surgery at our hospital between July 2020 and August 2022. A repeated-measures ANOVA was used to compare imaging indicators between periods. Forty-two patients were included in the study. The mean volume of intraoperative bleeding was 180 mL, and the mean operative time was 143 min. The mean follow-up time was 18 months. Apart from one case of peritoneal rupture, no other serious complications occurred. The postoperative foramen and disc height were both higher on average than before surgery. The spreader-assisted micro-Mini-ALIF is simple and easy to use. It can provide good intraoperative disc exposure, good discrimination of important structures, adequate spreading of the intervertebral space, and the restoration of the necessary intervertebral height, which is very helpful for less experienced surgeons.

The technique described in this article is well-suited to the Mini-ALIF procedure, allows for excellent exposure and decompression, and facilitates microscope-assisted manipulation.

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for ...

Treating Lumbar Spinal Stenosis with a Minimally Invasive Spine Surgery

Percutaneous Endoscopic Unilateral-Approach Bilateral Decompression for Lumbar Spinal Stenosis

Lumbar spinal stenosis (LSS) involves the narrowing of the spinal canal due to degenerative changes in the vertebral joints, intervertebral discs, and ligaments. LSS encompasses central canal stenosis (CCS), lateral recess stenosis (LRS), and intervertebral foramen stenosis (IFS). The utilization of lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) has gained popularity in the treatment of CCS and LRS. This popularity is attributed to the rapid development of endoscopic instruments and the progress of endoscopic philosophy.
In this technical report, a detailed introduction to the steps and key points of LE-ULBD is provided. Simultaneously, a retrospective review of 132 consecutive patients who underwent LE-ULBD for central canal and/or lateral recess stenosis was conducted. The outcomes after more than two years of follow-up were assessed using the visual analogue score (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) scores, and the modified MacNab criteria to evaluate surgical efficacy. All 132 patients underwent LE-ULBD successfully. Among them, 119 patients were rated as "excellent," while 13 patients were rated as "good" based on the modified MacNab criteria during the last follow-up. Incidental dural tears occurred in four cases, but there were no post-operative epidural hematomas or infections. The experience demonstrates that LE-ULBD is a less invasive, effective, and safe approach. It can be considered as an alternative option for treating patients with lumbar central canal stenosis and/or lateral recess stenosis.

Author Spotlight: Scope of LE-ULBD as a Safe, Effective, and Minimally Invasive Approach to Treat Lumbar Spinal Stenosis

The present protocol describes the steps and key points of lumbar endoscopic unilateral laminotomy for bilateral decompression for the treatment of degenerative lumbar spinal stenosis.

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Managing Knee Osteoarthritis Using Ultrasound-Guided Acupotomy

Clinical Effects of Ultrasound-Guided Acupotomy in Knee Osteoarthritis Treatment

The protocol presented here demonstrates the operation method of ultrasound-guided acupotomy for knee osteoarthritis (KOA), including patient recruitment, preoperative preparation, manual operation, and postoperative care. The purpose of this protocol is to relieve pain and improve knee function in patients with KOA. A total of 60 patients with KOA admitted between June 2022 and June 2023 were treated with ultrasound-guided acupotomy. Pathological changes and knee function scores were compared before and after the treatment. After 1 week of treatment, the synovial thickness of the suprapatellar bursae was significantly lesser than before treatment (p &lt; 0.05), the Hospital for Special Surgery Knee Score (HSS) was significantly higher than before treatment (p &lt; 0.05), the Visual analogue scale (VAS) was significantly lower than those of the control group (p &lt; 0.05) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were significantly lower than those of the control group (p &lt; 0.05). Therefore, ultrasound-guided acupotomy for the treatment of KOA can reduce synovial thickness, relieve pain, improve knee joint function, and have a remarkable curative effect.

Author Spotlight: Minimally Invasive Ultrasound-Guided Acupotomy in Knee Osteoarthritis Treatment

This paper introduces the operation method of ultrasound-guided acupotomy for knee osteoarthritis, which can reduce synovial thickness and improve knee joint function. It has the advantages of precise target, low treatment risk, few complications, and high safety.

The protocol presented here demonstrates the operation method of ultrasound-guided acupotomy for knee osteoarthritis (KOA), including patient recruitment, ...

Ultrasound-Guided Neuraxial Anesthesia for Complex Spine Anatomy

Spinal Sonography for Ultrasound-Guided Lumbar Neuraxial Anesthesia

Neuraxial anesthesia is one of the few remaining forms of regional anesthesia that relies on palpation and tactile feedback techniques to facilitate catheterization into the epidural space. Over two decades ago, spine ultrasonography was demonstrated to provide reliable guidance for locating the epidural space. Compared to the palpation technique, preprocedural ultrasonography has been shown to result in fewer needle punctures and fewer traumatic procedures, particularly in patients with abnormal or distorted spine anatomy (e.g., scoliosis, obesity). Despite its utility, the ultrasound-guided neuraxial technique is still marginally used, even for patients with abnormal anatomy. Some experts attribute this to cost, a relatively high success rate without ultrasound, and a lack of technical expertise, which is often tied to formal education and regular practice. Several proponents of the ultrasound technique emphasize that proficiency requires practice on patients with normal spine anatomy, though this training may not be as challenging as once thought. This protocol was designed to help all providers learn the basics of lumbar spine anatomy and how to apply this knowledge clinically. Through a series of videos, we will provide step-by-step instructions for performing neuraxial ultrasonography and offer practical tips for troubleshooting in cases of difficult anatomy.

Author Spotlight: Enhancing Success of Ultrasound-Guided Neuraxial Anesthesia in Cases with Difficult Anatomy

The protocol described here provides the basics of spine sonoanatomy and a quick, straightforward method for performing ultrasound-guided neuraxial anesthesia. Additionally, two handheld devices that enhance portability are presented, one of which uses pattern recognition software to aid in epidural space localization.

Neuraxial anesthesia is one of the few remaining forms of regional anesthesia that relies on palpation and tactile feedback techniques to facilitate ...

Intraoperative Ultrasound in Spinal Surgery

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