Endoscopic Lateral Approach for Dorsal Root Ganglion Burst Stimulation: Technical Note and Illustrative Case Series.

INTRODUCTION: Dorsal root ganglion (DRG) stimulation demonstrated superiority over traditional spinal cord stimulation with better pain relief and greater improvement of quality of life. However, leads specifically designed for DRG stimulation are difficult to implant in patients who previously underwent spinal surgery and show epidural scarring at the desired site of implantation because of the reduced stiffness of the lead. Nevertheless, recurrent leg or arm pain after spinal surgery usually manifests as a single level radiculopathy, which should theoretically be amenable to DRG stimulation. MATERIALS AND METHODS: We present the percutaneous transforaminal placement of cylindrical leads through a lateral endoscopic approach for DRG stimulation in burst mode. RESULTS: We could successfully show that percutaneous transforaminal lead placement is feasible in three illustrative cases. CONCLUSION: This technical note combines two innovations, one linked to the other. The first innovation involves a novel endoscopic lateral transforaminal approach to insert a cylindrical lead to the DRG. Because this electrode is compatible with burst stimulation-enabled devices, a second innovation consists of the application of burst stimulation on the DRG.

Interleukin-6 contributes to initiation of neuronal regeneration program in the remote dorsal root ganglia neurons after sciatic nerve injury.

To assess the potential role of IL-6 in sciatic nerve injury-induced activation of a pro-regenerative state in remote dorsal root ganglia (DRG) neurons, we compared protein levels of SCG-10 and activated STAT3, as well as axon regeneration in IL-6 knockout (IL-6ko) mice and their wild-type (WT) counterparts. Unilateral sciatic nerve compression and transection upregulated SCG-10 protein levels and activated STAT3 in DRG neurons not only in lumbar but also in cervical segments of WT mice. A pro-regenerative state induced by prior sciatic nerve lesion in cervical DRG neurons of WT mice was also shown by testing for axon regeneration in crushed ulnar nerve. DRG neurons from IL-6ko mice also displayed bilaterally increased levels of SCG-10 and STAT3 in both lumbar and cervical segments after sciatic nerve lesions. However, levels of SCG-10 protein in lumbar and cervical DRG of IL-6ko mice were significantly lower than those of their WT counterparts. Sciatic nerve injury induced a lower level of SCG-10 in cervical DRG of IL-6ko than WT mice, and this correlates with significantly shorter regeneration of axons distal to the crushed ulnar nerve. These results suggest that IL-6 contributes, at the very least, to initiation of the neuronal regeneration program in remote DRG neurons after unilateral sciatic nerve injury.

Percutaneous dorsal root ganglion block for treating lumbar compression fracture-related pain.

BACKGROUND: The pain of acute compression fracture in the lumbar spine may be refractory to conservative treatment, and surgery is not an optimal choice for the elderly or infirm individuals. Moreover, even vertebroplasty can cause many side effects such as chemical leak, adjacent segment instability, and residual pain. Percutaneous dorsal root ganglion block (PDRGB) possibly is an alternative therapeutic option. In this study, we evaluated the efficacy of pain relief and the rate of adjacent level compression fracture in patients with acute compression fracture of the lumbar spine. METHODS: We retrospectively reviewed 40 patients with lumbar compression fracture from 2013 to 2015. The patients were treated with navigation-assisted CT-guided PDRGB with steroid at the pathological level and at the adjacent level above and below. Therapeutic response was evaluated using the Numerical Rating Scale (NRS); and an optimal, acceptable, and unfavorable outcome were analyzed. RESULTS: Among the 40 patients treated, initial pain relief on the first day was dramatic, and the average NRS did not change significantly up to the first-year follow-up. The highest percentage of a good outcome, at 90% (37.5% with an optimal outcome, 52.5% with an acceptable outcome), was reported at 1 week postoperatively. The percentage of optimal outcomes increased even at the 1-year follow-up. No adjacent compression fracture was found in the group treated with PDRGB alone at the 1-year follow-up. CONCLUSIONS: PDRGB is a simple, safe, and minimally invasive procedure that showed immediate and prolonged improvement of pain in lumbar osteoporotic compression fracture patients who failed conservative treatment or had residual pain after vertebroplasty. However, continuous medication for osteoporosis was still required.

Creating a Strain Relief Loop during S1 Transforaminal Lead Placement for Dorsal Root Ganglion Stimulation for Foot Pain: A Technical Note.

Chronic neuropathic pain is often refractory to conventional medical treatments and leads to significant disability and socio-economic burden. Dorsal root ganglion (DRG) stimulation has recently emerged as a treatment for persistent neuropathic pain, but creating a strain relief loop at the S1 level has thus far been a challenging technical component of DRG lead placement. We describe a refined technique for strain relief loop formation at the S1 level using a transforaminal approach that we employed in a 45-year-old patient with intractable foot pain. We successfully placed a strain relief loop in the sacral space in a predictable and easily reproducible manner using a transforaminal anchorless approach. The patient experienced a decrease in visual analog pain score (85%), and improvement in function during the trial period, and proceeded with permanent implantation. The described sacral transforaminal strain relief loop formation technique appears to be a more reliable and predictable technique of DRG lead placement in the sacrum than those previously documented.

Localized Sympathectomy Reduces Mechanical Hypersensitivity by Restoring Normal Immune Homeostasis in Rat Models of Inflammatory Pain.

UNLABELLED: Some forms of chronic pain are maintained or enhanced by activity in the sympathetic nervous system (SNS), but attempts to model this have yielded conflicting findings. The SNS has both pro- and anti-inflammatory effects on immunity, confounding the interpretation of experiments using global sympathectomy methods. We performed a "microsympathectomy" by cutting the ipsilateral gray rami where they entered the spinal nerves near the L4 and L5 DRG. This led to profound sustained reductions in pain behaviors induced by local DRG inflammation (a rat model of low back pain) and by a peripheral paw inflammation model. Effects of microsympathectomy were evident within one day, making it unlikely that blocking sympathetic sprouting in the local DRGs or hindpaw was the sole mechanism. Prior microsympathectomy greatly reduced hyperexcitability of sensory neurons induced by local DRG inflammation observed 4 d later. Microsympathectomy reduced local inflammation and macrophage density in the affected tissues (as indicated by paw swelling and histochemical staining). Cytokine profiling in locally inflamed DRG showed increases in pro-inflammatory Type 1 cytokines and decreases in the Type 2 cytokines present at baseline, changes that were mitigated by microsympathectomy. Microsympathectomy was also effective in reducing established pain behaviors in the local DRG inflammation model. We conclude that the effect of sympathetic fibers in the L4/L5 gray rami in these models is pro-inflammatory. This raises the possibility that therapeutic interventions targeting gray rami might be useful in some chronic inflammatory pain conditions. SIGNIFICANCE STATEMENT: Sympathetic blockade is used for many pain conditions, but preclinical studies show both pro- and anti-nociceptive effects. The sympathetic nervous system also has both pro- and anti-inflammatory effects on immune tissues and cells. We examined effects of a very localized sympathectomy. By cutting the gray rami to the spinal nerves near the lumbar sensory ganglia, we avoided widespread sympathetic denervation. This procedure profoundly reduced mechanical pain behaviors induced by a back pain model and a model of peripheral inflammatory pain. One possible mechanism was reduction of inflammation in the sympathetically denervated regions. This raises the possibility that therapeutic interventions targeting gray rami might be useful in some inflammatory conditions.

Relevant Anatomy, Morphology, and Implantation Techniques of the Dorsal Root Ganglia at the Lumbar Levels.

OBJECTIVES: While dorsal root ganglion (DRG) stimulation has been available in Europe and Australia for the past five years and in the United States for the past year, there are no published details concerning the optimal procedures for DRG lead implantation. MATERIALS AND METHODS: We describe several techniques that can be applied to implant cylindrical leads over the DRG, highlighting some tips and tricks according to our experiences. Focus is mainly shifted toward implantations in the lumbar area. We furthermore give some insights in the results we experienced in Spain as well as some worldwide numbers. IMPLANT TECHNIQUES AND RESULTS: A 14-gauge needle is placed using a "2-Level Technique (2-LT)" or exceptionally a "1-Level Technique (1-LT)" or a "Primary- or Secondary Technique" at the level of L5. The delivery sheath, loaded with the lead, is advanced toward the targeted neural foramen. The lead is placed over the dorsal aspect of the DRG. A strain relief loop is created in the epidural space. Sheath and needle are retracted and the lead is secured using an anchor or anchorless technique. In Spain, 87.2% (N = 78) of the selected patients have been successfully implanted. Seven (8.9%) had a negative trial and three (4.2%) were explanted. Average VAS score decreased from 8.8 to 3.3 and on average 94.5% of the pain area was covered. In our center's subjects (N = 47 patients, 60.3% of all implanted patients in Spain), VAS scores decreased from an average of 8.8-1.7 and pain coverage averaged 96.4%. We used an average of 1.8 electrodes. Worldwide more than 4000 permanent cases have been successfully performed. CONCLUSIONS: We present implantation techniques whereby a percutaneous lead is placed over the DRG through the use of a special designed delivery sheath. Further investigation of the safety, efficacy, and sustainability of clinical outcomes using these devices is warranted.

Percutaneous Cervical Nucleoplasty vs. Pulsed Radio Frequency of the Dorsal Root Ganglion in Patients with Contained Cervical Disk Herniation; A Prospective, Randomized Controlled Trial.

BACKGROUND: Cervical neck pain is often caused by cervical disk pathology and may cause severe symptoms and disability. Surgeons and patients are increasingly aware of postsurgery-related complications. This stimulated the clinical usage of minimally invasive treatments such as percutaneous nucleoplasty (PCN) and pulsed radio frequency (PRF). However, scientific evidence on both treatments is limited. OBJECTIVE: Our objective was to evaluate the efficacy of PCN compared to PRF in patients with contained cervical disk herniation. METHODS: A prospective randomized clinical trial was conducted including 34 patients with radicular pain due to a single contained cervical disk herniation who were treated with either PCN or PRF. Demographic data were collected, and the Medical Outcomes Study 12-Item Short Form (SF-12) Health Survey, visual analog scale (VAS), and the Neck Disability Index (NDI) were completed 1, 2, and 3 months after treatment. Treatment satisfaction and complications were recorded. RESULTS: In the PCN group (n = 17, mean age 52.4 years, 10 female/7 male), patients were treated at C5 to C6 (8 cases) or C6 to C7 (9 cases). In the PRF group (n = 17, mean age 49.5 years, 8 female/9 male), patients were treated at C3 to C4 (1 case), C5 to C6 (10 cases), or C6 to C7 (6 cases). At 3 months, mean pain VAS improved significantly from baseline in the PCN group (mean improvement: 43.4 points) and in the PRF group (34.0 points). However, improvement in 1 group was not superior compared to the other group (P = 0.48). No serious complications were reported. CONCLUSION: Within 3 months, both PCN and PRF show significant pain improvement in patients with contained cervical disk herniation, but none is superior to the other. Both treatment options appear to be effective and safe in regular clinical practice.

Pulsed Radiofrequency of Dorsal Root Ganglia for the Treatment of Complex Regional Pain Syndrome in an Adolescent with Poliomyelitis Sequel: A Case Report.

OBJECTIVE: Complex regional pain syndrome (CRPS) is a painful and disabling syndrome in which the patient presents with neuropathic pain, edema, or vasomotor or pseudomotor abnormalities that are often refractory to treatment. Polio paralysis is caused by the damage or destruction of motor neurons in the spine, which lead to corresponding muscle paralysis. This report is a case report on the application of a pulsed radiofrequency (PRF) current to dorsal root ganglia (DRG) for the treatment of CRPS type 1 in an adolescent patient. DESIGN: Single case report. SETTING: Selcuk University Hospital. PATIENT: A 16-year-old girl who suffered from CRPS type 1 secondary to surgeries for the sequelae of poliomyelitis. INTERVENTIONS: PRF current application to the lumbar 4 and lumbar 5 DRG. OUTCOME MEASURES: Pain reduction. RESULTS: The patient had complete resolution of her symptoms, which was maintained at a 6-month follow-up. CONCLUSIONS: This case illustrates that PRF applied to lumbar 4 and lumbar 5 DRG may play a significant role in CRPS type 1 management after the surgical treatment of poliomyelitis sequelae in adolescent patients. Further randomized, controlled studies are needed to support this argument.

Response of cervicogenic headaches and occipital neuralgia to radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerve.

OBJECTIVE: This article investigates the degree and duration of pain relief from cervicogenic headaches or occipital neuralgia following treatment with radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerves. It also addresses the procedure's complication rate and patient's willingness to repeat the procedure if severe symptoms recur. METHODS: This is a single-center retrospective observational study of 40 patients with refractory cervicogenic headaches and or occipital neuralgia. Patients were all referred by a headache specialty clinic for evaluation for radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerves. After treatment, patients were followed for a minimum of 6 months to a year. Patient demographics and the results of radiofrequency ablation were recorded on the same day, after 3-4 days, and at 6 months to 1 year following treatment. RESULTS: Thirty-five percent of patients reported 100% pain relief and 70% reported 80% or greater pain relief. The mean duration of improvement is 22.35 weeks. Complication rate was 12-13%. 92.5% of patients reported they would undergo the procedure again if severe symptoms returned. CONCLUSIONS: Radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerve can provide many months of greater than 50% pain relief in the vast majority of recipients with an expected length of symptom improvement of 5-6 months.

Unveiling the role of dorsal root ganglia in spasticity reduction: Insights from contralateral seventh cervical nerve cross transfer surgery.

BACKGROUND: Central nervous system (CNS) disorders, such as stroke, often lead to spasticity, which result in limb deformities and significant reduction in quality of life. Spasticity arises from disruptions in the normal functioning of cortical and descending inhibitory pathways in the brainstem, leading to abnormal muscle contractions. Contralateral seventh cervical nerve cross transfer (CC7) surgery has been proven to effectively reduce spasticity, but the specific mechanism for its effectiveness is unclear. METHODS: This study aimed to investigate the changes in the dorsal root ganglia (DRG) following CC7 surgery. A comprehensive anatomical analysis was conducted through cadaveric study and magnetic resonance imaging (MRI) study, to accurately measure the regional anatomy of the C7 DRG. DRG perfusion changes were quantitatively assessed by comparing pre- and postoperative dynamic contrast-enhanced (DCE) MRI. RESULTS: In CC7 surgery, the C7 nerve root on the affected side is cut close to the DRG (3.6 ± 1.0 mm), while the C7 nerve root on the healthy side is cut further away from the DRG (65.0 ± 10.0 mm). MRI studies revealed that after C7 proximal neurotomy on the affected side, there was an increase in DRG volume, vascular permeability, and perfusion; after C7 distal neurotomy on the healthy side, there was a decrease in DRG volume, with no significant changes in vascular permeability and perfusion. CONCLUSION: This study provides preliminary insights into the mechanisms of spasticity reduction following CC7 surgery, indicating that changes in the DRG, such as increased vascular permeability and perfusion, could disrupt abnormal spinal γ-circuits. The resulting high-perfusion state of DRG, possibly due to heightened neuronal activity and metabolic demands, necessitating further research to verify this hypothesis.

Peripheral choline acetyltransferase in rat skin demonstrated by immunohistochemistry.

Conventional choline acetyltransferase immunohistochemistry has been used widely for visualizing central cholinergic neurons and fibers but not often for labeling peripheral structures, probably because of their poor staining. The recent identification of the peripheral type of choline acetyltransferase (pChAT) has enabled the clear immunohistochemical detection of many known peripheral cholinergic elements. Here, we report the presence of pChAT-immunoreactive nerve fibers in rat skin. Intensely stained nerve fibers were distributed in association with eccrine sweat glands, blood vessels, hair follicles and portions just beneath the epidermis. These results suggest that pChAT-positive nerves participate in the sympathetic cholinergic innervation of eccrine sweat glands. Moreover, pChAT also appears to play a role in cutaneous sensory nerve endings. These findings are supported by the presence of many pChAT-positive neuronal cells in the sympathetic ganglion and dorsal root ganglion. Thus, pChAT immunohistochemistry should provide a novel and unique tool for studying cholinergic nerves in the skin.

A systematic review: current and future directions of dorsal root ganglion therapeutics to treat chronic pain.

OBJECTIVE: The purpose of the study was to systematically review the historical therapeutics for chronic pain care directed at the dorsal root ganglion (DRG) and to identify future trends and upcoming treatment strategies. METHODS: A literature search on bibliographic resources, including EMBASE, PubMed Cochrane Database of Systemic Reviews from literature published from 1966 to December 1, 2012 to identify studies and treatments directed at the DRG to treat chronic pain, and was limited to the English language. Case series, case reports, and preclinical work were excluded. Information on emerging technologies and pharmacologics were captured separately, as they did not meet the inclusion criteria. RESULTS: The literature review yielded three current clinical treatment strategies: ganglionectomy, conventional radiofrequency treatment of the dorsal root ganglion, and pulsed radiofrequency treatment of the DRG. Seven studies were identified utilizing ganglionectomy, 14 for conventional radiofrequency, and 16 for pulsed radiofrequency. Electrical stimulation and novel therapeutic delivery strategies have been proposed and are in development. CONCLUSIONS: Despite a robust understanding of the DRG and its importance in acute nociception, as well as the development and maintenance of chronic pain, relatively poor evidence exists regarding current therapeutic strategies. Novel therapies like electrical and pharmacologic strategies are on the horizon, and more prospective study is required to better qualify the role of the DRG in chronic pain care.

Routine sectioning of the C2 nerve root and ganglion for C1 lateral mass screw placement in children: surgical and functional outcomes.

PURPOSE: Adult studies have shown that sectioning the C2 nerve root and ganglion may facilitate placement of C1 lateral mass screws and lead to decreased operative time and blood loss. We report the functional outcomes and complications following routine sectioning of the C2 nerve root and ganglion, which have not been reported in pediatric patients. METHODS: Fifteen consecutive pediatric patients underwent C1 lateral mass screw insertion and bilateral C2 nerve root and ganglion sectioning. Clinical and radiographic assessments were performed at follow-up. Numbness in the C2 distribution and/or occipital neuralgia, operative times, estimated blood loss (EBL), length of stay (LOS), and complications were recorded. RESULTS: Average follow-up time was 35.7 months. Overall mean operative time was 250.5 min, LOS was 8.46 days, and EBL was 337 cc. When considering only atlantoaxial fusions, mean operative time was 180.7 min and EBL was 97.1 cc. There were no intraoperative complications, and no patient reported new onset occipital neuralgia or numbness in the C2 distribution that would interfere with daily living. Of the patients, 93 % achieved Lenke fusion grade A; one achieved Lenke fusion grade B. CONCLUSIONS: Routine C2 nerve root sectioning and ganglionectomy enhanced surgical exposure of the C1 lateral mass and C1-2 facet joint, potentially maximizing fusion rate and minimizing intraoperative complications. This technique may yield favorable operative times, EBL, and LOS in children undergoing C1 lateral mass screw insertion without negatively affecting functional outcome.

Percutaneous dorsal root ganglion lysis with phenol for the treatment of pain associated with thoracic compression fracture.

BACKGROUND: Symptomatic thoracic compression fracture is one of the most common causes of back pain in elderly. Although vertebroplasty is widely utilized in patients when conservative treatment fails, we introduced an alternative percutaneous technique for the treatment of thoracic compression pain. METHODS: This in a retrospective study. The analysis was performed on 28 consecutive patients who underwent undergoing percutaneous dorsal root ganglion lysis with phenol for the treatment of pain associated with thoracic compression fracture. An acceptable treatment outcome was operationally defined as a pain intensity numerical rating scale (NRS) score of 3 or lower or EQ-5D index of 0.672 or higher. The primary outcome was pain relief and acceptable treatment outcome at 1 day, 1 week, 1 month, and 1 year. RESULTS: Of the 28 cases treated with our procedures, the change in mean NRS score between baseline and one day was -2.5 (95 % CI -1.6 ~ -3.4, p < 0.001), between baseline and one week was -4.7 (-4.1 to -5.3, p < 0.001), between baseline and one month was -5.8 (-5.2 to -6.5, p < 0.001), and between baseline and one year was -6.3 (-5.6 to -7.1, p < 0.001). An acceptable treatment outcome was 14 % one day after the procedure, 46 % at one week, 72 % at one month, and 84 % at one year. Complication rate was 3.6 %. CONCLUSIONS: For thoracic compression fracture patients, percutaneous dorsal root ganglion lysis with phenol is an effective, and safe alternative treatment method worth considering. Pain relief is fast and persists for one year.

Infraareolar access for thoracoscopic sympathectomy to treat primary hyperhidrosis.

We herein present a new technique for performing thoracoscopic sympathectomy to treat primary hyperhidrosis in both genders and all ages through the mammary infraareolar access associated with the axillary access. We believe that these points of access are feasible and safe, and result in an excellent cosmetic outcome without compromising the efficacy of the thoracoscopic sympathectomy. The existence of adhesions between the parietal and visceral pleura, the presence of large breasts, and lactation made it difficult to perform the surgery, but did not make it impossible to apply the technique using the infraareolar access. However, the presence of breast implants is a contraindication for the new access.

Chronic hypertrophic ganglioneuritis mimicking spinal nerve neoplasia: clinical, imaging, pathologic findings, and outcome after surgical treatment.

OBJECTIVE: To report the clinical, imaging, pathologic findings, surgical planning, and long-term outcome after surgery in a dog with neurologic deficits because of a hypertrophic ganglioneuritis that compressed the spinal cord. STUDY DESIGN: Clinical report. ANIMAL: An 8-year-old male intact Yorkshire terrier. METHODS: The dog had ambulatory tetraparesis and neurologic examination was consistent with a C1-C5 myelopathy. Magnetic resonance imaging (MRI) revealed enlargement of the left C2 spinal nerve causing compression of the spinal cord. The main differential diagnosis was spinal nerve neoplasia with compression and possibly spinal cord invasion. On ultrasonography, there was enlargement of the spinal nerve and fine needle aspiration did not show evidence of neoplasia. Fascicular biopsy of the spinal nerve was consistent with enlargement because of chronic inflammation (hypertrophic neuritis). RESULTS: Hemilaminectomy followed by durotomy and rhizotomy allowed resection of an intradural-extramedullary mass that was the enlarged left C2 spinal nerve. Histopathology was consistent with a hypertrophic ganglioneuritis. Thirteen months later the dog remained free of clinical signs. CONCLUSION: Hypertrophic neuritis affecting the spinal nerves may be misdiagnosed as spinal nerve neoplasia that in dogs is usually malignant with a poor prognosis. Focal spinal nerve lesions with compression of the spinal cord evident on MRI may be inflammatory and are not necessarily a neoplastic condition.

[Generation and characterization of peripheral nerve animal model of pure motor/sensory nerve fibers].

OBJECTIVE: To generate peripheral nerve animal model of pure motor nerve fibers/pure sensory nerve fibers, and identify them. METHODS: The SPF SD rats were adopted in this study, and divided into 3 groups. In group A, we ablated L2-L4 ventral roots (VRs) to generate peripheral nerve animal model of pure sensory fibers. In group B, we ablated L2-L4 dorsal root ganglions (DRGs) to generate peripheral nerve animal model of pure motor fibers. Two time end-points were set as 2 weeks and 4 weeks. Neuron cells in lumbar spinal cords were detected by immunohistochemical staining with antibody of neuronal nuclei (NeuN). Motor neuron cells in lumbar spinal cords of pure motor fiber animal models and sensory neuron cells in lumbar spinal cords of pure sensory fiber animal models were counted respectively, and then compared to that of normal animals. Femoral nerves distal to the furcation were stained in osmium tetroxide, and then myelinated nerve fibers in the muscle branch and cutaneous branch of femoral nerve were counted respectively. RESULTS: The mean numbers of sensory neuron cells and motor neuron cells in normal lumbar spinal cords were 62.57 ± 1.02 and 29.73 ± 3.03 per 10 × 20 visual field respectively. For different end-points, the mean numbers of sensory neuron cells after ablating vental foots were 62.12 ± 1.77 (2 weeks), 62.15 ± 1.32 (4 weeks) per 10 × 20 visual field respectively; the mean numbers of motor neuron cells after ablating DRGs were 30.12 ± 0.44 (2 weeks), 30.00 ± 1.87 (4 weeks) per 10 × 20 visual field respectively. In group A, motor axons in muscle branch were degenerated as the sensory axons in muscle branch and cutaneous branch were not changed. The senory axons in femoral nerve for the two end-points were 1 558.17 ± 50.14 (2 weeks) and 1 544.00 ± 47.42 (4 weeks). In group B, sensory axons in muscle branch were degenerated as the motor axons were reserved. The motor axons in muscle branch for the two end-points were 387.67 ± 48.50 (2 weeks) and 393.50 ± 27.86 (4 weeks). There was no statistically significant difference in these mean numbers for the two end-points. The degenerating axons and myelin sheath had not been totally eliminated by the endpoint of 2 weeks. CONCLUSION: Peripheral nerve animal model of pure motor fibers can be generated by ablating L2-L4 DRGs; peripheral nerve animal model of pure sensory fibers can be generated by ablating L2-L4 ventral roots. The degenerating axons and myelin sheath have been totally eliminated by the end-point of 4 weeks. Ablating the ventral roots does not influence the survival of sensory neuron cells; and ablating the DRGs does not influence the survival of motor neuron cells.

A Procedure for Mouse Dorsal Root Ganglion Cryosectioning.

High-quality mouse dorsal root ganglion (DRG) cryostat sections are crucial for proper immunochemistry staining and RNAscope studies in the research of inflammatory and neuropathic pain, itch, as well as other peripheral neurological conditions. However, it remains a challenge to consistently obtain high-quality, intact, and flat cryostat sections onto glass slides because of the tiny sample size of the DRG tissue. So far, there is no article describing an optimal protocol for DRG cryosectioning. This protocol presents a step-by-step method to resolve the frequently encountered difficulties associated with DRG cryosectioning. The presented article explains how to remove the surrounding liquid from the DRG tissue samples, place the DRG sections on the slide facing the same orientation, and flatten the sections on the glass slide without curving up. Although this protocol has been developed for cryosectioning the DRG samples, it can be applied for the cryosectioning of many other tissues with a small sample size.

Alternative Dorsal Root Ganglion Neuromodulation Electrode Implantation: A Report of 2 Cases with 3 Different Techniques.

BACKGROUND AND STUDY AIMS: The traditional percutaneous placement of dorsal root ganglion (DRG) electrodes may not be eligible for every patient. In this tertiary spine surgery and interventional pain therapy center, alternative neurostimulation implantation techniques were developed and applied where standard percutaneous approaches failed or were contraindicated. CASE PRESENTATION: Three alternative implantation techniques can be used: (1) open surgical placement of DRG leads, (2) two-lead insertion via a lateral to medial transforaminal approach (level L3), and (3) percutaneous approach with two leads close to the spinal nerves L4 (peripheral nerve stimulation). RESULTS: The placement of the leads occurred without complications and resulted in similar expected outcomes as with the common percutaneous technique with long-term stable pain suppression at 7 months and 1 year. CONCLUSIONS: In patients in whom the DRG cannot be approached by the standard percutaneous approach, at least three alternatives may be used in experienced hands resulting in stable pain suppression of similar magnitude.

Whole Central and Peripheral Nervous System Mice Dissection.

Animal models represent the workhorse of the neuroscience field. Despite this, today, there is still no step-by-step protocol to dissect a complete rodent nervous system, nor is there a complete schematic representing it that is freely available. Only methods to harvest the brain, the spinal cord, a specific dorsal root ganglion, and the sciatic nerve (separately) are available. Here, we provide detailed pictures and a schematic of the central and peripheral murine nervous system. More importantly, we outline a robust procedure to perform its dissection. The 30 min pre-dissection step allows isolating the intact nervous system within the vertebra with muscles free of viscera and skin. A 2-4 h dissection follows it under a micro-dissection microscope to expose the spinal cord and the thoracic nerves, and finally peel the whole central and peripheral nervous system off the carcass. This protocol represents a significant step forward in studying the anatomy and pathophysiology of the nervous system globally. For example, the dissected dorsal root ganglions from a neurofibromatosis type I mice model can be further processed for histology to unravel changes in tumor progression.