Name: laminotomy for lumbar dorsal root ganglion access and injection in swine
Uploaded: 2017-10-10T15:00:00
Description: Watch this Scientific Journal Video about Laminotomy for Lumbar Dorsal Root Ganglion Access and Injection in Swine at JoVE.com

The study was performed with support by the Schulze Family Foundation (to A.S.B.).

All methods described here have been approved by the Institutional Animal Care and Use Committee (IACUC) of Mayo Clinic.
1. Prerequisites of Rigor and Reproducibility
<ol>
	<li>To ensure rigor of design, follow national standards of good laboratory practices are at all times and obtain internal approval by IACUC (or similar committee) prior to any animal involvement in experiments. 
	NOTE: This protocol was designed to maintain a clinically faithful approach. Thus, the materials, instru...

<ol>
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We sought to describe a method for surgical exposure of DRG via laminotomy and intraganglionic injection in a healthy large animal species, specifically, swine. In rodents, a similar method has been detailed 12 and used to deliver conventional pharmacologic agents 8,10 and viral vectors 6,7,9,12 to DRG. ...

Dorsal root ganglia (DRG) are anatomically discrete, neuronal collections located along the vertebral column. Each DRG contains the primary sensory neurons that encode and relay peripheral stimuli to the central nervous system (CNS) from specific body regions. For instance, the pain of osteoarthritis begins when pain receptors located about a joint perceive noxious stimuli. This process is termed nociception. Long-term awareness of noxious stimuli leads to chronic pain 1.
Chronic pain is a frequent subject of preclinical study 2 where one goal is to develop useful methods for targeted delivery of analgesics to DRG, such as intraganglionic injection 3. However, DRG are difficult to access because they reside within the boney confines of intervertebral foramina 4. Several groups have successfully overcome this obstacle through the use of spine surgery in rodents 5,6,7,8,9,10.
In the clinic, laminectomy is a common spine operation and refers to surgical removal of the vertebral lamina, thereby unroofing the vertebral canal 11. Incorporation of surgical techniques to afford direct DRG access has been successful in rodents 5,12, however, translation may be unrealistic considering differences in size of relevant structures and how that influences pharmacokinetics or technical feasibility 13,14. For example, one study determined the transverse spinal cord diameter at T10 to be 3.0, 7.0, and 8.2 mm for rat, pig, and human, respectively 15. Thus, large animal models better approximate human dimensions of nervous structures.
In swine, Raore et al. used multi-level laminectomy to gain access to the cervical spinal cord for multiple intraspinal injections 16. The procedure was well tolerated and led to a phase I clinical trial where comparable surgical outcomes were documented 17. These results encourage continued use of preclinical large animal models as predictors of technical feasibility and safety in humans.
To date, no detailed methodology exists for surgical access and injection of DRG in a large animal species. To narrow this translational gap, we report a protocol for DRG exposure and injection via laminotomy in swine. Standard neurosurgical techniques, instruments, and materials were used and the method was designed to mimic modern surgical practice. We demonstrate intraganglionic injection using an aqueous solution for lumbar DRG and confirm successful delivery via histology after post-operative day 21.

<table border="0" cellpadding="0" cellspacing="0" width="1311">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Large humane animal sling</td>
			<td style="width:167px;">Britz &#38; Company</td>
			<td style="width:119px;">002539</td>
			<td style="width:484px;">Modified to include abdominal aperture</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Adhesive patient return electrode - 9 inch</td>
			<td style="width:167px;">Medtronic</td>
			<td style="width:119px;">E7506</td>
			<td style="width:484px;">-</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Ranger blood &#38; fluid warming system</td>
			<td style="width:167px;">3M</td>
			<td style="width:119px;">24500</td>
			<td style="width:484px;">-</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Lactated Ringer&#39;s fluid</td>
			<td style="width:167px;">Hospira</td>
			<td style="width:119px;">0409-7953-09</td>
			<td style="width:484px;">-</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Force air warming device</td>
			<td style="width:167px;">3M</td>
			<td style="width:119px;">77500</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:543px;">Duraprep solution with applicator, 26 ml (0.7% iodine povacrylex, 74% isopropyl alcohol</td>
			<td style="width:167px;">3M</td>
			<td style="width:119px;">8630</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Sterile disposable surgical towels</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">MDT2168286</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Ioban 2 incise drape</td>
			<td style="width:167px;">3M</td>
			<td style="width:119px;">6651EZSB</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Disposable suction canister and tubing</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">DYND44703H</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Button switch electrosurgical monopolar pencil</td>
			<td style="width:167px;">Medtronic</td>
			<td style="width:119px;">E2450H</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Fine smooth straight bipolar electrosurgical forceps, 4 1/2 inch</td>
			<td style="width:167px;">Bovie</td>
			<td style="width:119px;">A826</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">#15 blade</td>
			<td style="width:167px;">Miltex</td>
			<td style="width:119px;">4-315</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">#11 blade</td>
			<td style="width:167px;">Miltex</td>
			<td style="width:119px;">4-311</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">4x4 surgical gauze</td>
			<td style="width:167px;">Dynarex</td>
			<td style="width:119px;">3262</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Weitlaner self-retaining retractor, 8 inch</td>
			<td style="width:167px;">Miltex</td>
			<td style="width:119px;">11-618</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Meyerding self-retaining retractor, 1x2 3/8 inch</td>
			<td style="width:167px;">Sklar</td>
			<td style="width:119px;">42-2078</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Gelpi self-retaining retractor, 7 inch</td>
			<td style="width:167px;">Sklar</td>
			<td style="width:119px;">60-6570</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Freer elevator, 5 mm</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">MDS4641518F</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Bone wax</td>
			<td style="width:167px;">Ethicon</td>
			<td style="width:119px;">W31G</td>
			<td style="width:484px;">-</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Spurling intervertebral disc rongeur, 3 mm</td>
			<td style="width:167px;">Sklar</td>
			<td style="width:119px;">42-2852</td>
			<td style="width:484px;">-</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Spurling 45-degree, up-biting Kerrison rongeur, 2 mm</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">MDS4052802</td>
			<td style="width:484px;">-</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Leksell angled rongeur, 2 mm</td>
			<td style="width:167px;">Sklar</td>
			<td style="width:119px;">40-4097</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Gelfoam, size 50</td>
			<td style="width:167px;">Pfizer</td>
			<td style="width:119px;">AZL32301</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Cottonoid patty</td>
			<td style="width:167px;">Medtronic</td>
			<td style="width:119px;">8004007</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Frazier suction tip, 6 Fr</td>
			<td style="width:167px;">Sklar</td>
			<td style="width:119px;">50-2006</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Frazier suction tip, 10 Fr</td>
			<td style="width:167px;">Sklar</td>
			<td style="width:119px;">50-2010</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Dandy blunt right angle nerve hook</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">MDS4005220</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Nylon suture, 6-0</td>
			<td style="width:167px;">Ethicon</td>
			<td style="width:119px;">697G</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Castroviejo smooth micro needle holder</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">MDG2428614</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">22 gauge Quinke point spinal needle</td>
			<td style="width:167px;">Halyard Health</td>
			<td style="width:119px;">18397</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:543px;">32 gauge CED needle with locking Luer hub</td>
			<td style="width:167px;">See comments</td>
			<td style="width:119px;">n/a</td>
			<td style="width:484px;">As in: Pleticha, J., Maus, T.P., Christner, J.A., Marsh, M.P., Lee, K.H., Hooten, W.M., Beutler, A.S. Minimally invasive convection-enhanced delivery of biologics into dorsal root ganglia: validation in the pig model and prospective modeling in humans. Technical note. J Neurosurg. 121(4), 851-8 (2014).</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Polyethylene tubing, 5 feet</td>
			<td style="width:167px;">Scientific Commodities</td>
			<td style="width:119px;">BB31695-PE/05</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Monoject syringe, 3 ml</td>
			<td style="width:167px;">Kendall</td>
			<td style="width:119px;">SY15352</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">NanoJet syringe pump</td>
			<td style="width:167px;">Chemyx</td>
			<td style="width:119px;">10050</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">DAPI</td>
			<td style="width:167px;">Sigma-Aldrich</td>
			<td style="width:119px;">D9542</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Fast Green FCF</td>
			<td style="width:167px;">Sigma-Aldrich</td>
			<td style="width:119px;">F7252</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Bulb irrigation syringe</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">DYND20125</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Fine-toothed Adson forceps</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">MDS1000212</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Vicryl suture, 0</td>
			<td style="width:167px;">Ethicon</td>
			<td style="width:119px;">J603H</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Vicryl suture, 2-0</td>
			<td style="width:167px;">Ethicon</td>
			<td style="width:119px;">J317H</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Needle counter</td>
			<td style="width:167px;">Medline</td>
			<td style="width:119px;">NC20FBRGS</td>
			<td style="width:484px;">-</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:543px;">Steri-strip skin closure, 1/2x4 inch</td>
			<td style="width:167px;">3M</td>
			<td style="width:119px;">R1547</td>
			<td style="width:484px;">-</td>
		</tr>
	</tbody>
</table>

laminotomy for lumbar dorsal root ganglion access and injection in swine

Dorsal root ganglia (DRG) are anatomically well defined structures that contain all primary sensory neurons below the head. This fact makes DRG attractive targets for injection of novel therapeutics aimed at treating chronic pain. In small animal models, laminectomy has been used to facilitate DRG injection because it involves surgical removal of the vertebral bone surrounding each DRG. We demonstrate a technique for intraganglionic injection of lumbar DRG in a large animal species, namely, swine. Laminotomy is performed to allow direct access to DRG using standard neurosurgical techniques, instruments, and materials. Compared with more extensive bone removal via laminectomy, we implement laminotomy to conserve spinal anatomy while achieving sufficient DRG access. Intraoperative progress of DRG injection is monitored using a non-toxic dye. Following euthanasia on post-operative day 21, the success of injection is determined by histology for intraganglionic distribution of 4&#39;,6-diamidino-2-phenylindole (DAPI). We inject a biologically inactive solution to demonstrate the protocol. This method could be applied in future preclinical studies to target therapeutic solutions to DRG. Our methodology should facilitate testing the translatability of intraganglionic small animal paradigms in a large animal species. Additionally, this protocol may serve as a key resource for those planning preclinical studies of DRG injection in swine.

Histologic assessment of injectate spread 
Successful delivery of injectate to DRG is determined by histologic assessment of DAPI spread. The technique involves positioning the needle tip in the three-dimensional center of the DRG. Therefore, successful delivery is determined by evaluating the extent of DAPI staining from histologic sections both near (central DRG sections) and distant (peripheral DRG sections) to the needle tip. Figure 1A and Figur...

Watch this Scientific Journal Video about Laminotomy for Lumbar Dorsal Root Ganglion Access and Injection in Swine at JoVE.com

Laminotomy for Lumbar Dorsal Root Ganglion Access and Injection in Swine

We describe a method for laminotomy in swine that provides access to lumbar dorsal root ganglia (DRG) for intraganglionic injection. Injection progress is monitored intraoperatively and histologically confirmed up to 21 days after surgery. This protocol could be used for future preclinical studies involving DRG injection.

Dorsal root ganglia (DRG) are anatomically well defined structures that contain all primary sensory neurons below the head. This fact makes DRG attractive ...

Research

JoVE Journal

Neuroscience

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