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

Summary

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

Abstract

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.

Introduction

Transpedicular screw fixation is a gold-standard treatment for degenerative lumbar spine and bursting fracture because it involves three columns of the spine and achieves stabilization^1,2. However, most patients who undergo such surgery also have osteoporosis^3,4. Many studies have evaluated the fixation strength and the osseointegration status of transpedicular screws, because the loosening of pedicle screws currently in use has been reported in patients with osteoporosis^5,6.

Protocol

The Institutional Animal Care and Use Committee of Chonbuk National University approved this study. The treatment, use, and handling of animals followed all guidelines and policies. Maintain the operating room at 24 °C.

1. Anesthesia

1. Acclimatize miniature pigs, aged 12 months, in the experimental unit for at least one week. Perform a clinical examination measuring the respiratory rate, heartrate, and body temperature. Do not feed each miniature pig for 12 h before the anesthesia procedure.
2. Inject atropine (0.05 mg/kg) and ketamin (20 mg/kg)/ xylaxine (2 mg/kg)  into the lateral cervical muscle region, be....

Results

A detailed protocol for anesthesia, surgery, and harvest for the evaluation of transpedicular screws using an in vivo porcine lumbar spine model is described here. This protocol is suitable for a number of downstream analyses, including mechanical testing (Figure 1), quantitative micro-CT evaluation (Figure 2), and histology (Figure 3). Representative mechanical testing (Figure 1) shows the mean extraction torsio.......

Discussion

The evaluation of transpedicular screws in the porcine spine requires much time and effort. First, the miniature pig is a large animal. For animal care and anesthesia, the researcher needs a specialized protocol. Second, surgery should maintain an environment similar to that of human surgery. The purpose of evaluating pedicle screws in the porcine spine is to develop an efficient screw that can be applied to humans. Third, evaluating the long-term stability of transpedicular screws requires about three months after the s.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Miniature pig	OrientBio
Atropine	Jeil pharmaceutical	A04900241	Anesthesia
Over-the needle plastic catheter	BD	REF382412	Maintenance of IV line
Ketamine	Yuhan	A04502441	Anesthesia
Xylazine	Bayer Korea	A00800071	Anesthesia
Laryngoscope	Karl storz		Intubation
Endotracheal tube	Covidien		Intubation
Isoflurane	JW pharmaceutical Co	A02104781	Anesthesia
Eye ointment	Hanlim pharma	A37851721	Protection of pig's eye
Cefazolin	Donga pharma	A01503951	Antibiotics
Saline	JW pharmaceutical Co	A02151392	Maintenance of fluid homeostasis
Fentanyl	Hana pharm	C03200032	Pain control
Enrofloxacin	Bayer	93106-60-6	Antibiotics
Morphine	Myungmoon pharma	C03700091	Pain control
Meloxicam	Boehringer Ingelheim	A07600711	Antibiotics
Povidone-iodine	Hyundai pharma		Wound dressing
Scalpel blade size 15	Braun	I1 BB515	Skin incision
Cobb elevator	Codman	65-2546	Dissection of muscle
Burr	Medtronic		Making of starting point of screw
Rongeur	Aesculap	FO515R	Making of starting point of screw
Guide pin (K-wire)	CE	01067803	Guidance of screw trajectory
C-arm	GE	OEC 9800 plus	Guidance of screw trajectory
Portable X-ray	Siemens	Mobile XP hybrid	Guidance of screw trajectory
Pedicle probe	OtisBiotech	SPI-02-01	Guidance of screw trajectory
Pedicle sounding device	OtisBiotech	SPI-03-01	Guidance of screw trajectory
Pedicle screw	OtisBiotech	MS-40025
Posterior fixator systems	OtisBiotech
Rod	OtisBiotech	ROD-60140	Rigid fixation between screws
Universal handle	OtisBiotech	SPI-08-01	To fix the screws to the rod
Straight socket wrench	OtisBiotech	SPI-06-01	To fix the screws to the rod
counter torque wrench	OtisBiotech	SPI-07-01	To fix the screws to the rod
Bulb irrigation syringe	Hyupsug medical	HS-IR-140	Irrigation
Silicone drain	Sewon medical	2205-006	To drain the fluid at the surgical site
3.0 metric absorbable suture	Ethicon	BA1673H	Muscle suture
2.0 metric nonabsorbable nylon suture	Ethicon	W1626T	Skin suture
Gauze	Kingphar Korea	KP120-06
Pentobarbital	Hanlim pharma	645301221	Euthanasia
Oscillating saw	Zimmer		Harvest spine
Tower forceps	Aesculap	BF461R	Harvest spine