Name: A Rat Model of Tibial Cortex Transverse Transport for the Treatment of Lower Limb Ischemia (Video) | JoVE Journal
Uploaded: 2026-03-06T14:40:00.000+00:00
Duration: 9 min 56 s
Description: Learn tibial cortex transverse transport for treating lower limb ischemia using a reliable rat model. This method enables visualization of blood flow recovery and exploration of revascularization mechanisms.

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All animal experiments were approved by the Animal Ethics Committee of the First Affiliated Hospital of Guangxi Medical University (approved No. 2025-E0642). Male Sprague-Dawley rats (300-350g) were housed in the Guangxi Medical University Animal Research Center under standardized conditions. Rats were provided with normal chow and clean drinking water ad libitum and maintained on a 12 h artificial light/dark cycle. The animal facility was kept at a controlled temperature of 20-26 &#176;C with a relative humidity of 40%-70%. All surgical instruments were thoroughly sterilized prior to use. Detailed information on all reagents and materials used in this study is provided in Table 1.
Euthanasia was performed by intraperitoneal injection of an overdose of sodium pentobarbital. Death was confirmed by the permanent cessation of heartbeat and respiration, pupillary dilation, and the absence of response to noxious stimuli. All procedures were conducted by trained personnel to minimize animal distress, and the euthanasia protocol had been reviewed and approved in advance by the Institutional Animal Care and Use Committee.
1. External fixator for TTT
<ol>
	<li>Use a scaled-down, custom-designed version of the clinical tibial cortex transverse transport external fixator (TTT-EF), consisting of a bone fragment traction unit and an external fixation frame.</li>
	<li>Enable vertical mobilization of both components by incorporating an internal screw-thread mechanism (Figure 1).</li>
	<li>Drill two through-holes on each side of the cross-sections of both the traction unit and the fixation frame to allow insertion of Kirschner wires.</li>
	<li>Insert the Kirschner wires through the designated holes and secure them laterally using hexagonal screws to ensure stabilization.</li>
	<li>Connect the traction component of the TTT-EF to the bone fragment using 0.8 mm Kirschner wires.</li>
	<li>Anchor the fixation component to the proximal and distal ends of the tibia using 1.0 mm Kirschner wires.</li>
</ol>
2. Surgical procedure
<ol>
	<li>Perform the TTT procedure on 8-week-old male Sprague-Dawley (SD) rats. Anesthetize the rats by intraperitoneal injection of 0.35 mg/kg sodium pentobarbital and 0.3 mg/kg chloral hydrate.</li>
	<li>Assess the anesthetic effect by testing the pedal withdrawal reflex and corneal reflex. Continuously monitor vital signs and the depth of anesthesia throughout the procedure. Apply ophthalmic ointment to the rat&#39;s eyes prior to surgery to protect the cornea, following the Guidelines for the Use of Laboratory Animals.</li>
	<li>Shave the surgical area and administer 0.5% lidocaine to minimize postoperative pain.</li>
	<li>Make a 10 mm skin incision in the right inguinal region using a No. 11 scalpel.</li>
	<li>Bluntly dissect the fascia to expose the superficial femoral artery.</li>
	<li>Isolate the artery between the femoral nerve and the superficial femoral vein using ophthalmic forceps. Ligate and transect both ends of the artery.</li>
	<li>Suture the incision using 4-0 absorbable suture.</li>
	<li>Make a vertical 15 mm incision on the medial upper tibia using a No. 11 scalpel.</li>
	<li>Separate the subcutaneous tissue and underlying muscle carefully to avoid periosteal injury. Gently dissect the soft tissue to fully expose the medial tibial surface.</li>
	<li>Outline the bone fragment area (8 mm &#215; 4 mm) on the medial tibial surface using a surgical blade. Drill closely spaced perforations along the marked boundary using a 0.6 mm drill bit. Create a bone window fragment (8 mm &#215; 4 mm) on the upper medial tibia.</li>
	<li>Implant two 0.8 mm threaded Kirschner wires into the bone fragment, spaced 0.5 mm apart, to facilitate transport. Connect the Kirschner wires to the TTT-EF and secure them.</li>
	<li>Insert two 1.0 mm Kirschner wires on either side of the fragment, penetrating the posterior cortex of the tibia.</li>
	<li>Assemble and install the TTT-EF.</li>
	<li>Perform osteotomy along the marked lines using ophthalmic scissors.</li>
	<li>Gently elevate the bone fragment to enable vertical mobility, avoiding marrow injury.</li>
	<li>Irrigate the surgical site with 10% povidone-iodine followed by sterile saline.</li>
	<li>Suture the incision in layers using 4-0 absorbable suture.</li>
	<li>Administer buprenorphine (0.05 mg/kg) subcutaneously immediately post surgery. Continue dosing every 12 h for up to 3 days to ensure effective analgesia.</li>
</ol>
3. Postoperative monitoring
<ol>
	<li>Closely monitor animals after surgery to ensure proper recovery and detect potential complications early. Examine animals every 6-8 h during the first 48 h postoperatively. Assess general activity, posture, grooming behavior, food and water intake, and surgical incision condition.</li>
	<li>Perform monitoring at least once daily from postoperative Day 3 through the distraction and consolidation phases. Confirm adequate recovery by verifying normal ambulation, stable body weight, consistent food and water intake, and absence of wound discharge, excessive swelling, or behavioral signs of pain.</li>
	<li>Continue analgesia as needed in accordance with institutional guidelines.</li>
	<li>Treat wound infections (e.g., erythema, swelling, purulent discharge) with local wound care and systemic antibiotics, following veterinary recommendations.</li>
	<li>Correct any loosening or displacement of the external fixator immediately under brief anesthesia to maintain alignment and enable accurate distraction.</li>
	<li>Promptly assess and manage any potential complications. Evaluate animals with severe complications affecting mobility, feeding, or wound healing in consultation with veterinary staff.</li>
	<li>Euthanize animals humanely if they meet predefined humane endpoint criteria.</li>
</ol>
4. Bone fragment transport protocol
<ol>
	<li>Use the tibial cortex transverse transport external fixator (TTT-EF) to perform postoperative bone fragment transport.</li>
	<li>Designate Day 1 after surgery as the latency period. 
	NOTE: Do not manipulate the bone fragment during this period.</li>
	<li>Initiate the upward transport phase on Day 2. Advance the bone fragment at a rate of 0.5 mm every 12 h for 5 consecutive days (Day 2-Day 6). Pause the transport process on Day 7 to allow for stabilization.</li>
	<li>Initiate the downward transport phase on Day 8.</li>
	<li>Retract the bone fragment at the same rate of 0.5 mm every 12 h for 5 days (Day 8-Day 12). Ensure that the bone fragment returns to its original position by the end of Day 12.</li>
	<li>Continue with a 2-day consolidation phase (Days 13-14), with no further transport.</li>
	<li>Remove the external fixator at the end of the consolidation phase. 
	NOTE: Refer to Figure 2 for a visual timeline of the TTT transport procedure and evaluation schedule.</li>
</ol>
5. Evaluation
NOTE: Use imaging techniques to evaluate both the bone fragment position and blood flow restoration.
<ol>
	<li>Perform X-ray imaging of the lower limbs on Days 1, 7, and 12 to monitor the progression and final position of the transported bone fragment.
	<ol>
		<li>Anesthetize rats at designated imaging time points using 2.0% isoflurane in oxygen.</li>
		<li>Place each rat on a temperature-maintained imaging platform equipped with a warming pad to prevent hypothermia during the procedure.</li>
		<li>Monitor anesthetic depth by assessing respiratory rate and pedal reflex to ensure stable immobilization.</li>
		<li>Position the limbs and external fixator in a standardized orientation across all animals to minimize variability in X-ray acquisition.</li>
		<li>Acquire X-ray images to confirm bone fragment displacement and repositioning.</li>
	</ol>
	</li>
	<li>Conduct vascular perfusion imaging on Day 19 postoperatively to assess microvascular perfusion in the lower limb.
	<ol>
		<li>Euthanize the rats and perfuse contrast agent via the femoral artery to visualize vasculature.</li>
		<li>Place the euthanized rats in a standardized supine position for consistent imaging setup.</li>
		<li>Allow complete vascular filling by perfusing the contrast agent through the femoral artery under steady room-temperature conditions.</li>
		<li>Conduct vascular imaging to assess microvascular architecture and perfusion. Ensure all specimens are aligned consistently with identical limb orientation and fixator alignment to support reproducibility across imaging sessions.</li>
		<li>Use the resulting images to evaluate the restoration of blood flow and vascular architecture in the lower limbs.</li>
	</ol>
	</li>
</ol>

<ol><li>Jones, D. W., Farber, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Review+of+the+global+vascular+guidelines+on+the+management+of+chronic+limb-threatening+ischemia%5BTitle%5D)+AND+%22JAMA+Surg%22%5BJournal%5D)">Review of the global vascular guidelines on the management of chronic limb-threatening ischemia.</a> JAMA Surg. 155 (2), 161(2020).</li>
<li>Levin, S. R., Arinze, N., Siracuse, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Lower+extremity+critical+limb+ischemia%3A+a+review+of+clinical+features+and+management%5BTitle%5D)+AND+%22Trends+Cardiovasc+Med%22%5BJournal%5D)">Lower extremity critical limb ischemia: a review of clinical features and management.</a> Trends Cardiovasc Med. 30 (3), 125-130 (2020).</li>
<li>Aboyans, V., Chastaingt, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((What+LEADs+to+the+under-treatment+of+patients+with+lower-extremity+artery+disease%5BTitle%5D)+AND+%22Eur+J+Prev+Cardiol%22%5BJournal%5D)">What LEADs to the under-treatment of patients with lower-extremity artery disease.</a> Eur J Prev Cardiol. 30 (11), 1090-1091 (2023).</li>
<li>Liu, Z., Xu, C., Yu, Y., Tu, D., Peng, Y., Zhang, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Twenty+years+development+of+tibial+cortex+transverse+transport+surgery+in+PR+China%5BTitle%5D)+AND+%22Orthop+Surg%22%5BJournal%5D)">Twenty years development of tibial cortex transverse transport surgery in PR China.</a> Orthop Surg. 14 (6), 1034-1048 (2022).</li>
<li>Ilizarov, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+tension-stress+effect+on+the+genesis+and+growth+of+tissues%3A+part+II.+The+influence+of+the+rate+and+frequency+of+distraction%5BTitle%5D)+AND+%22Clin+Orthop+Relat+Res%22%5BJournal%5D)">The tension-stress effect on the genesis and growth of tissues: part II. The influence of the rate and frequency of distraction.</a> Clin Orthop Relat Res. 239, 263-285 (1989).</li>
<li>Ilizarov, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+tension-stress+effect+on+the+genesis+and+growth+of+tissues%3A+part+I.+The+influence+of+stability+of+fixation+and+soft-tissue+preservation%5BTitle%5D)+AND+%22Clin+Orthop+Relat+Res%22%5BJournal%5D)">The tension-stress effect on the genesis and growth of tissues: part I. The influence of stability of fixation and soft-tissue preservation.</a> Clin Orthop Relat Res. 238, 249-281 (1989).</li>
<li>Chen, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Proximal+tibial+cortex+transverse+distraction+facilitating+healing+and+limb+salvage+in+severe+and+recalcitrant+diabetic+foot+ulcers%5BTitle%5D)+AND+%22Clin+Orthop+Relat+Res%22%5BJournal%5D)">Proximal tibial cortex transverse distraction facilitating healing and limb salvage in severe and recalcitrant diabetic foot ulcers.</a> Clin Orthop Relat Res. 478 (4), 836-851 (2020).</li>
<li>Beckman, J. A., Schneider, P. A., Conte, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Advances+in+revascularization+for+peripheral+artery+disease%3A+revascularization+in+PAD%5BTitle%5D)+AND+%22Circ+Res%22%5BJournal%5D)">Advances in revascularization for peripheral artery disease: revascularization in PAD.</a> Circ Res. 128 (12), 1885-1912 (2021).</li>
<li>Zhu, Y. L., Qu, L., Ye, Z. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Tibial+cortex+transverse+distraction+for+primary+lymphoedema+in+the+lower+limb%3A+a+case+report%5BTitle%5D)+AND+%22J+Orthop+Transl%22%5BJournal%5D)">Tibial cortex transverse distraction for primary lymphoedema in the lower limb: a case report.</a> J Orthop Transl. 25, 25-27 (2020).</li>
<li>Yang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Tibial+cortex+transverse+transport+accelerates+wound+healing+via+enhanced+angiogenesis+and+immunomodulation%5BTitle%5D)+AND+%22Bone+Joint+Res%22%5BJournal%5D)">Tibial cortex transverse transport accelerates wound healing via enhanced angiogenesis and immunomodulation.</a> Bone Joint Res. 11 (4), 189-199 (2022).</li>
<li>Hasanpour, M., Mitricheva, E., Logothetis, N., Noori, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Intensive+longitudinal+characterization+of+multidimensional+biobehavioral+dynamics+in+laboratory+rats%5BTitle%5D)+AND+%22Cell+Rep%22%5BJournal%5D)">Intensive longitudinal characterization of multidimensional biobehavioral dynamics in laboratory rats.</a> Cell Rep. 35 (2), 108987(2021).</li>
<li>Modlinska, K., Pisula, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+Norway+rat%2C+from+an+obnoxious+pest+to+a+laboratory+pet%5BTitle%5D)+AND+%22eLife%22%5BJournal%5D)">The Norway rat, from an obnoxious pest to a laboratory pet.</a> eLife. 9, e50651(2020).</li>
<li>Su, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Finite+element+analysis+safety+of+tibial+cortex+transverse+transport%5BTitle%5D)+AND+%22Bone+Joint+Res%22%5BJournal%5D)">Finite element analysis safety of tibial cortex transverse transport.</a> Bone Joint Res. 14 (4), 281-291 (2025).</li>
<li>Zhen, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Finite+element+analysis+of+biomechanical+effects+in+rat+tibia+during+tibial+cortex+transverse+transport%5BTitle%5D)+AND+%22Front+Bioeng+Biotechnol%22%5BJournal%5D)">Finite element analysis of biomechanical effects in rat tibia during tibial cortex transverse transport.</a> Front Bioeng Biotechnol. 13, 1670040(2025).</li>
</ol>

The authors have no competing interests to declare.

All procedures involving anesthesia and surgery were performed with careful attention to animal safety and institutional animal care guidelines. The depth of anesthesia was confirmed prior to incision using pedal withdrawal or corneal reflex testing and was monitored regularly throughout the procedure. Adequate thermal support (such as a heating pad) was provided to prevent hypothermia, and ophthalmic ointment was applied to protect the corneas during prolonged anesthesia.
Potential risks asso...

Lower limb ischemic diseases, such as arteriosclerosis obliterans (ASO), thromboangiitis obliterans (TAO), and diabetic foot (DF), are characterized by restricted arterial blood flow to the lower extremities1,2. In the early stages, patients typically experience intermittent claudication and resting pain. As the disease progresses, prolonged ischemia can result in tissue necrosis, infection, and, in severe cases, limb amputation1. Current standard treatments-including pharmacological therapy, endovascular interventions, and open surgical procedures-often yield limited efficacy, particularly in advanced stages of the disease3.
Tibial cortex transverse transport (TTT) is an innovative therapeutic strategy for the treatment of various lower limb ischemic diseases4. Rooted in the Ilizarov method and the &#34;tension-stress rule&#34;5,6, this technique involves creating a mobile cortical bone flap fragment in the tibia through osteotomy. A continuous, slow, and controlled distraction force is then applied to stimulate the regeneration of bone, blood vessels, and surrounding soft tissues. This regenerative process facilitates the reestablishment of microcirculation and helps restore the balance of oxygen supply in the affected limb. Ultimately, TTT leads to improved blood perfusion and functional recovery in ischemic tissues7.
Conventional vascular reconstruction techniques for lower limb ischemia can restore blood flow in large arteries of the calf but are often ineffective in revascularizing smaller arteries in the foot or promoting the repair and regeneration of damaged microvessels, limiting their ability to fully resolve ischemia8. TTT continuously applies traction to the bone and surrounding soft tissues, thereby inducing the robust release of chemotactic factors and cytokines9. These chemotactic factors regulate various functions of stem cells and, under ischemic conditions, are abundantly secreted into circulation. They actively recruit endogenous stem cells to sites of injury, thereby facilitating vascular repair and regeneration without requiring direct stem cell transplantation. Owing to these advantages, TTT has emerged as a promising therapeutic strategy for lower limb ischemia and is increasingly employed in the treatment of diverse ischemic conditions affecting the lower extremities7,9,10.
Although rabbits and dogs are commonly used in fundamental TTT research, the lack of suitable analytical tools for these species limits mechanistic investigations. In contrast, the rat TTT model offers greater compatibility with available molecular and imaging techniques while maintaining practicality and lower cost, making it a more accessible and reproducible platform for mechanistic studies. However, to date, no study has systematically described or evaluated the efficacy of TTT in a rat model of lower limb ischemia.
The rat TTT model requires refined microsurgical skills due to the small tibial size and thin cortex, and its distraction range is limited by cortical thickness. These practical constraints should be taken into account when evaluating the model&#39;s suitability for specific research environments.
In this study, we developed a rat-specific TTT model by replicating the core structure and operative principles of the clinical tibial transverse transport apparatus. The procedure was refined from clinically validated protocols to ensure feasibility and consistency in small animals. Our objective is to establish and validate a standardized and reproducible rat TTT model suitable for investigating angiogenesis and mechanotransduction in ischemic limb disease.

<table><tbody><tr><td>Micro Transverse Retractor</td><td>Tianjin Xinzhong Medical Equipment Co., Ltd</td><td>A61B17/66</td><td>Perform bone fragment traction</td></tr><tr><td>Small Orthopedic Drill</td><td>Yancheng Ruiao Technology Co. LTD</td><td>RA-II</td><td>For tibial drilling osteotomy</td></tr><tr><td>0.6 mm Stainless Steel Drill Bit</td><td>Changzhou Borche Medical Equipment Co., Ltd</td><td>-</td><td>For tibial drilling osteotomy</td></tr><tr><td>0.8 mm Thread type Kirschner wire</td><td>Changzhou Borche Medical Equipment Co., Ltd</td><td>-</td><td>For attachment of bone flaps and retractor</td></tr><tr><td>1.0 mm Thread type Kirschner wire</td><td>Changzhou Borche Medical Equipment Co., Ltd</td><td>-</td><td>For fixation of retractor</td></tr><tr><td>Pentobarbital sodium</td><td>Shanghai Pharmaceuticals Holding Co., Ltd</td><td>-</td><td>For anesthetizing animals</td></tr><tr><td>Allen key</td><td>Changzhou Borche Medical Equipment Co., Ltd</td><td>-</td><td>For fixing screws</td></tr><tr><td>Buprenorphine</td><td>Shanghai Pharmaceuticals Holding Co., Ltd</td><td></td><td>For analgesia animal</td></tr><tr><td>MICROFIL</td><td>Flow Tech,Inc Co., Ltd</td><td></td><td>Angiography of animals</td></tr><tr><td>Isoflurane</td><td>Hebei Yipin Pharmaceutical Co., Ltd.</td><td></td><td>For induction and maintenance of inhalation anesthesia</td></tr><tr><td>Lidocaine Hydrochloride (0.5%)</td><td>Hebei Yipin Pharmaceutical Co., Ltd.</td><td></td><td>Used for local infiltration to reduce postoperative pain and minimize tissue irritation during surgical procedures</td></tr></tbody></table>

a rat model of tibial cortex transverse transport for the treatment of lower limb ischemia

A Rat Model of Tibial Cortex Transverse Transport for the Treatment of Lower Limb Ischemia

Tibial cortex transverse transport (TTT) is an emerging surgical technique used to promote revascularization in ischemic lower limbs. This video demonstrates a reproducible rat model of TTT, detailing the surgical creation of a cortical bone fragment, the transport protocol, and postoperative assessments. The procedure enables controlled upward and downward transport of a bone fragment to stimulate angiogenic responses. Representative X-ray images acquired on postoperative days 1, 7, and 12, together with microvascular perfusion imaging performed on Day 19 after euthanasia, show clear bone fragment movement and improved limb perfusion following TTT.
This model provides a practical and reproducible platform for investigating the molecular mechanisms underlying TTT-induced angiogenesis and evaluating potential therapeutic strategies for ischemic diseases. To construct this model, we simulated the clinical TTT procedure in Sprague-Dawley rats, involving three main surgical steps: ligation of the superficial femoral artery, creation and mobilization of a cortical bone fragment, and application of a custom external fixator. Over 12 days, the fragment was gradually transported forward and then backward. Perfusion imaging confirmed enhanced vascularization in the ischemic limb after the completion of the transport cycle. Overall, this standardized rat model closely mimics clinical TTT procedures and offers a valuable experimental system for studying mechanotransduction, angiogenesis, and vascular regeneration in ischemic limb conditions.

Figure 3 illustrates the procedure for constructing a TTT-treated lower limb ischemia animal model. In our hands, the procedure demonstrated a surgical success rate of approximately 90%. The limited number of failures was largely attributable to technical issues such as external fixator loosening or intraoperative bone fragment fracture, which rendered subsequent distraction infeasible. The model was established by exposing and ligating the superficial femora...

This procedure demonstrates tibial cortex transverse transport in rats, enabling visualization and analysis of revascularization during limb ischemia.

Tibial cortex transverse transport (TTT) is an emerging surgical technique used to promote revascularization in ischemic lower limbs. This video ...

Lower limb ischemia mainly reduces blood flow to the leg and can seriously affect tissue healings. Tibial cortex transverse transport of TTT is a surgical technique that help promotes new blood vessels growth and improve circulations. To better study how this works, we developed a rat model that closely replicate the clinical TTT procedure.This model is straightforward, reliable, and easy to reproduce, allowing us to visualize blood flow recoveries and explore the mechanisms behind TTT. Begin with a fully anesthetized adult SD rat. In accordance with the guidelines for the use of laboratory animals, ophthalmic ointment was applied to protect the cornea and thermal support and physiological monitoring were provided throughout the procedure.Before the operation, hair around the surgical site was completely removed and the area was disinfected with 10%povidone iodine. To facilitate the procedure, 0.5%lidocaine hydrochloride was locally injected into the surgical region. We then proceeded with the invasive portion of the protocol.To establish the lower limb ischemia model, a 10 millimeters incision was made in the right groin using a number 11 scalpel blade to expose the superficial femoral artery vein and nerve. Using ophthalmic forceps, the superficial femoral artery was carefully dissected free between the femoral nerve and the superficial femoral vein. After isolating the artery, both the proximal and distal ends were ligated with absorbable sutures, followed by transection of the vessel and trimming of excess suture material.Finally, the surgical area is re-sterilized using 10%iodophor solution, and then the surgical incision is closed with four to zero absorbable sutures. Use suture scissors to cut off excess threads. Next, to expose the tibia, a 20 millimeter skin incision was made along the medial aspect of the right lower limb using a number 11 scalpel blade, followed by careful layer by layer dissection of the subcutaneous tissue and muscle.Throughout this process, particular attention was paid to avoid damaging the periosteum. An eight millimeters times four millimeters bone fragment was then outlined on the flat surface of the tibial cortex using the scalpel blade. Next, the holes are drilled along the pre-marked scribed lines using a 0.6 millimeters diameter drill bit in a continuous and tight pattern, ensuring that each hole is evenly spaced along the cut line.After that, we will install a custom designed external fixator and fix the bone fragment. To place two fixation pins in the center of the bone fragment, positioning was first performed using a 0.6 mm drill bit with the two points spaced approximately 0.5 millimeters apart. A 0.8 mm Kirschner wires were then inserted perpendicularly through the marked points into the cortical bone to a depth of three millimeters, taking care to avoid penetrating the contralateral cortex.Afterwards cut off the excessively long Kirschner wire, leaving about 10 millimeters, then drilled another Kirschner wire in the same manner. For ease of subsequent manipulation, three edges of the bone fragment were cut using ophthalmic scissors, leaving the medial edge intact. This preserved edge provides a stable plane for fixation and facilitates controlled mobilization of the fragment.A custom designed external fixator was subsequently installed over this region. This device is a scaled down version of the tibial transverse transport external fixator, TTTF, and consists of a traction component and a fixation component, which enable controlled movement of the bone fragment through rotation of an internal threaded mechanism. The traction component of the external fixator was mounted along the two Kirschner wires, followed by attachment of the fixation component.After fixation, the miniature lateral transfer frame was fixed to the tibia of the rat using a one millimeter diameter Kirschner wire. The Kirschner wire need to pass completely through the tibia in order to firmly and stably attach the mini lateral transfer device to the tibia, then use the Allen key to tighten the external screws. The other side has been fixed in the same way, and finally the excessively long Kirschner wire has been cut off.Finally, the medial edge of the bone fragment was cut to completely free it. Rotation of the threaded mechanism allows upward or downward movement of the fragment. Finally, use 10%iodophor to completely sterilize the surgical area.It then used absorbable sutures to close the muscle and skin layer by layer to ensure no continued bleeding, and then the finished suture site is sterilized again. To prevent postoperative pain, buprenorphine was administered subcutaneously. During the first three postoperative days, buprenorphine was given every 12 hours for continued analgesia thereafter as needed.Subsequently, the rats were placed in a clean cage, and provided with an appropriate environment and temperature, then closely monitored for recovery. The therapeutic effect of this procedure is achieved through controlled movement of the bone fragment. We designed a specific transport protocol for fragment mobilization.After a one day latency period, upward transport of the bone fragment was initiated on day one. This phase lasted for five days during which the fragment was advanced 0.5 millimeters every 12 hours. Upon completion of the upward transport, the fragment was kept stationary for one day, followed by the initiation of downward transport on day seven.The downward phase similarly lasted five days, with a fragment moved 0.5 millimeters every 12 hours. After a total of 12 days of transport, the bone fragment returned to its original position. Finally, a two-day consolidation phase was applied to further stabilize the fragment.To evaluate the therapeutic effect of the TTT procedure in the animal models, X-ray images and vascular perfusion images was performed to assess the positions of the bone fragment and microvascular perfusions in the lower limb. X-ray examination showed that the bone fragment was at its lowest position on day one and day 12, and reached its highest point on day seven. No fractures were observed around the corticotomy site throughout the transport process.Additionally, vascular profusion imaging on day 19 demonstrated that although ligation of the superficial femoral artery reduced blood profusion in the lower limb, animals that underwent the TTT procedure exhibited markedly enhanced microvascular profusion. These findings indicate that TTT exerts a positive effect on improving blood circulation in ischemic limbs. Our study establishes a rat model for TTT-based treatments of lower limb ischemia.TTT was shown to promote microcirculatory reconstructions and effectively eradicate ischemic conditions in the affecting limb. This model provides a valuable platforms for exploring the underlying mechanisms by which TTT is exerts therapeutic effect in ischemic disease.

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This paper presents a partial heterotopic osteomyocutaneous flap transplantation protocol in rats and its potential outcomes in the mid-term follow-up.

Partial Heterotopic Hindlimb Transplantation Model in Rats

This protocol describes the tibial neuroma transposition model, which entails a lesion of the tibial nerve with subsequent transposition of the proximal nerve end toward a subcutaneous pretibial or lateral position. Behavioral testing of neuroma pain and plantar hyperalgesia is quantified using Von Frey monofilaments.

Surgery and Behavioral Testing in the Tibial Neuroma Transposition Model in Rats

This protocol demonstrates how to perform a below-knee amputation in rats and to immediately perform targeted muscle reinnervation (iTMR) to investigate strategies to treat and prevent amputation-related pain and to better understand pain mechanisms associated with amputation.

Rat Hindlimb Below-Knee Amputation Model and Immediate Targeted Muscle Reinnervation

Learn tibial cortex transverse transport for treating lower limb ischemia using a reliable rat model. This method enables visualization of blood flow recovery and exploration of revascularization mechanisms.

A Rat Model of Tibial Cortex Transverse Transport for the Treatment of Lower Limb Ischemia

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