Technical guideline for intra-prepontine cisternal drug delivery via spinal puncture through subarachnoid catheterization. / ç»è„ŠæŸ±æ¤Žé—´éš™ç©¿åˆºè››ç½‘è†œä¸‹è ”è„‘æ¡¥å‰æ± ç½®ç®¡è¯ç‰©è¾“æ³¨æŠ€æœ¯åº”ç”¨æŒ‡å—.

OBJECTIVES: The distribution characteristics of intrathecal drugs and the limitation of current catheterization techniques make traditional intrathecal analgesic treatment nearly useless for refractory craniofacial pain, such as trigemina neuralgia. This technical guideline aims to promote the widespread and standardize the application of intra-prepontine cisternal drug delivery via spinal puncture and catheterization. METHODS: A modified Delphi approach was used to work for this guideline. On the issues related to the intra-prepontine cisternal targeted drug delivery technique, the working group consulted 10 experts from the field with 3 rounds of email feedback and 3 rounds of conference discussion. RESULTS: For the efficacy and safety of the intra-prepontine cisternal targeted drug delivery technique, a consensus was formed on 7 topics (with an agreement rate of more than 80%), including the principles of the technique, indications and contraindications, patient preparation, surgical specifications for intra-prepontine cisternal catheter placement, analgesic dosage coordination, analgesic management, and prevention and treatment of complications. CONCLUSIONS: Utilizing the intra-prepontine cisternal drug infusion system to manage refractory craniofacial pain could provide advantages in terms of minimally invasive, secure, and effective treatment. This application can not only alleviate the suffering of individuals experiencing the prolonged pain but also support the maintenance of quality of life and dignity in their final moments, justifiing its widespread dissemination and standardized adoption in domestic and international professional fields.

Multi-Objective NSGA-II Optimization for Broadband Beamforming with Spherical Harmonic Domain Assistance.

Sidelobe suppression is a major challenge in wideband beamforming for acoustic research, especially in high noise and reverberation environments. In this paper, we propose a multi-objective NSGA-II wideband beamforming method based on a spherical harmonic domain for spherical microphone arrays topology. The method takes white noise gain, directional index and maximum sidelobe level as the optimization objectives of broadband beamforming, adopts the NSGA-II optimization strategy with constraints to estimate the Pareto optimal solution, and provides three-dimensional broadband beamforming capability. Our method provides superior sidelobe suppression across different spherical harmonic orders compared to commonly used multi-constrained single-objective optimal beamforming methods. We also validate the effectiveness of our proposed method in a conference room setting. The proposed method achieves a white noise gain of 8.28 dB and a maximum sidelobe level of -23.42 dB at low frequency, while at high frequency it yields comparable directivity index results to both DolphChebyshev and SOCP methods, but outperforms them in terms of white noise gain and maximum sidelobe level, measuring 16.14 dB and -25.18 dB, respectively.

Implantable Peripheral Nerve Stimulation for Trigeminal Neuropathic Pain: A Systematic Review and Meta-Analysis.

OBJECTIVES: Implantable peripheral nerve stimulation has been increasingly used to treat neuropathic pain. This neuromodulation strategy may be an alternative option for intractable trigeminal neuropathic pain; however, evidence for this treatment approach remains limited. A systematic review was conducted to identify studies of patients that underwent peripheral nerve stimulation implantation for trigeminal neuropathic pain. MATERIALS AND METHODS: Databases including, PubMed, EMBASE, and Cochrane Library were searched up to October 5, 2020. The primary outcomes were changes in pain scores and response rates of neuromodulation therapy. A random effects model was used for meta-analysis. Subgroup analysis was performed to examine the source of heterogeneity. RESULTS: Thirteen studies including 221 participants were evaluated. The estimated response rate of neuromodulation treatment was 61.3% (95% CI: 44.4-75.9%, I2  = 70.733%, p < 0.0001) at the last follow-up. The overall reduction in pain scores was 2.363 (95% CI: 1.408-3.319, I2  = 85.723%, p < 0.0001). Subgroup analysis further confirmed that stimulation target (peripheral branch vs. trigeminal ganglion vs. trigeminal nerve root) contributed the heterogeneity across enrolled studies. Better clinical outcome was associated with stimulation of the trigeminal peripheral branch (p < 0.0001). CONCLUSION: Peripheral nerve stimulation may be a promising approach in the management of trigeminal neuropathic pain, especially for patients intractable to conventional therapy.

A novel neuromodulation strategy to enhance the prefrontal control to treat pain.

Effective pharmacological treatment options for chronic pain remain very limited, and continued reliance on opioid analgesics has contributed to an epidemic in the United States. On the other hand, nonpharmacologic neuromodulatory interventions provide a promising avenue for relief of chronic pain without the complications of dependence and addiction. An especially attractive neuromodulation strategy is to optimize endogenous pain regulatory circuits. The prefrontal cortex is known to provide top-down control of pain, and hence neuromodulation methods that selectively enhance the activities in this brain region during pain episodes have the potential to provide analgesia. In this study, we designed a low-frequency (2 Hz) electrical stimulation protocol to provide temporally and spatially specific enhancement of the prefrontal control of pain in rats. We showed that low-frequency electrical stimulation of the prelimbic region of the prefrontal cortex relieved both sensory and affective responses to acute pain in naive rats. Furthermore, we found that low-frequency electrical stimulation of the prefrontal cortex also attenuated mechanical allodynia in a rat model of chronic pain. Together, our findings demonstrated that low-frequency electrical stimulation of the prefrontal cortex represents a promising new method of neuromodulation to inhibit pain.

The Central Analgesic Mechanism of YM-58483 in Attenuating Neuropathic Pain in Rats.

Calcium channel antagonists are commonly used to treat neuropathic pain. Their analgesic effects rely on inhibiting long-term potentiation, and neurotransmitters release in the spinal cord. Store-operated Ca(2+)channels (SOCCs) are highly Ca(2+)-selective cation channels broadly expressed in non-excitable cells and some excitable cells. Recent studies have shown that the potent inhibitor of SOCCs, YM-58483, has analgesic effects on neuropathic pain, but its mechanism is unclear. This experiment performed on spinal nerve ligation (SNL)-induced neuropathic pain model in rats tries to explore the mechanism, whereby YM-58483 attenuates neuropathic pain. The left L5 was ligated to produce the SNL neuropathic pain model in male Sprague-Dawley rats. The withdrawal threshold of rats was measured by the up-down method and Hargreaves' method before and after intrathecal administration of YM-58483 and vehicle. The SOCCs in the spinal dorsal horn were located by immunofluorescence. The expression of phosphorylated ERK and phosphorylated CREB, CD11b, and GFAP proteins in spinal level was tested by Western blot, while the release of proinflammatory cytokines (IL-1ß, TNF-α, PGE2) was measured by enzyme-linked immunosorbent assay (ELISA). Intrathecal YM-58483 at the concentration of 300 µM (1.5 nmol) and 1000 µM (10 nmol) produced a significant central analgesic effect on the SNL rats, compared with control + vehicle (n = 7, P < 0.001). However, both could not prevent the development of neuropathic pain, compared with normal + saline (P < 0.001). Immunofluorescent staining revealed that Orai1 and STIM1 (the two key components of SOCCs) were located in the spinal dorsal horn neurons. Western blot showed that YM-58483 could decrease the levels of P-ERK and P-CREB (n = 10, #P < 0.05), without affecting the expression of CD11b and GFAP (n = 10, #P > 0.05). YM-58483 also inhibited the release of spinal cord IL-1ß, TNF-α, and PGE2, compared with control + vehicle (n = 5, #P < 0.001). The analgesic mechanism of YM-58483 may be via inhibiting central ERK/CREB signaling in the neurons and decreasing central IL-1ß, TNF-α, and PGE2 release to reduce neuronal excitability in the spinal dorsal horn of the SNL rats.

Short-term cervical spinal cord stimulation for central post-stroke pain: a case report and literature review.

Introduction: Post-stroke central pain is disabling yet ineffectively treated with routine medical intervention. In this study, the authors presented an alternative neuromodulation therapy and conducted a brief narrative literature review to examine current evidence of spinal cord stimulation treatment for central post-stroke pain. Case presentation: Here, the authors reported a case of severe post-stroke syndrome, who achieved satisfactory improvement of pain symptom, as well as muscle rigidity with a novel neuromodulation therapy of short-term implantation of cervical spinal cord stimulation. Clinical discussion: It remains a great challenge in the management of post-stroke pain, which in turn significantly reduces the quality of life and worsens the burden on the public health system. Spinal cord stimulation therapy is an emerging neuromodulation approach to restore pathological pain status and functional impairment to provide a prospective insight into neuromodulation and rehabilitation options in the management of post-stroke syndrome. Conclusion: A potential role of spinal cord stimulation in the treatment of post-stroke pain is proposed in combined with traditional medication or other neuromodulation strategies, to achieve better control of pain in the future.

Correlation between spinal cord stimulation analgesia and cortical dynamics in pain management.

AIM: Spinal cord stimulation (SCS) is an effective method to treat neuropathic pain. It is necessary to identify the responders of SCS analgesia before implantation. The aim of this study is to investigate the relationship between the cortical dynamics and SCS analgesia responders in pain management. METHODS: Resting-state EEG recording was performed in patients who underwent short-term implantation of spinal cord stimulation for pain therapy. We then did spectral analysis to capture the pattern of cortical oscillation between neuromodulation therapy analgesia responders and nonresponders. RESULTS: About 58.3% (14 out of 24) of participants were considered as analgesia responders, with average visual analogue scores reduction of 4.8 ± 1.0 after surgery, and 2.1 ± 0.7 for the nonresponder subgroup, respectively. The alpha oscillation was significantly enhanced in responder cohort compared with nonresponders. We also observed an increasing spectral power of gamma band in responders. Furthermore, the attenuation of pain severity was significantly correlated with the global alpha oscillation activity (r = 0.60, P = 0.002). Likely, positive and significant correlation was found between the pain relief and gamma activity (r = 0.58, P = 0.003). CONCLUSIONS: Distinct pattern of neural oscillation is associated with the analgesic effect of spinal cord stimulation in pain management, enhancement of cortical alpha and gamma oscillation may be a predictor of analgesia responders.

A new dual function dorsal root ganglion stimulation in pain management: a technical note and case report.

Sensitization of dorsal horn ganglion sensory neuron plays a crucial role in the maintenance of chronic pain disorder. Multiple interventions targeting dorsal horn ganglion can provide considerable relief of pain, including selective nerve root block, pulsed radiofrequency, and electrical nerve stimulation technique. It remains controversial about the superiority of neuromodulation mentioned above due to distinct pattern of analgesic mechanism. Here, we reported one 71-year-old male presenting at our pain clinic with severe, unilateral lower limb pain caused by postherpetic neuralgia. An implantable stimulator with dual neuromodulation mode, combining pulsed radiofrequency with electrical nerve stimulation, was then placed into the lateral epidural space adjacent to dorsal root ganglion at L4 level. Standard stimulation programing was performed with technicians to achieve satisfactory control of pain, with numerical rating scale decreasing from 8 to 2 postoperatively. This novel dual function neuromodulation strategy may provide an alternative option for pain management for those with intractable neuropathic pain.

Dual-neuromodulation strategy in pain management of herpes zoster ophthalmicus: retrospective cohort study and literature review.

BACKGROUND: Effective pain control of herpes zoster ophthalmicus (HZO) is not only essential to attenuate the clinical symptoms but to reduce the risk of postherpetic neuralgia development. Recently, neuromodulation therapy has been one promising option for neuropathic pain and increasingly applied in management of zoster-related pain. One key factor of neuromodulation treatment is the therapeutic site for the impaired nerves. In this study we aim to investigate one novel dual-neuromodulation strategy, targeting the level of the peripheral branch and trigeminal ganglion, in the pain management of HZO. METHODS: Dual neuromodulation strategy combining short-term peripheral nerve stimulation (PNS) with pulsed radiofrequency (PRF) of trigeminal ganglion was compared with single PNS treatment for HZO-related pain. Clinical recordings of patients were retrospectively reviewed. The primary outcome was the pain severity, assessed by the visual analogue scale (VAS) before and after neuromodulation therapy. RESULTS: PNS achieved significant relief of pain with or without PRF treatment before discharge, which provided enduring therapeutic effect up to 12-month follow-up. The mean reduction of VAS was 6.7 ± 1.4 in dual modulation therapy (n = 13) at last follow-up and 5.4 ± 1.5 in PNS subgroup (n = 20), respectively. Moreover, dual modulation strategy provided better control of pain compared with PNS therapy alone at each time point. CONCLUSION: It is feasible and effective to combine the PNS and PRF in pain management of HZO. This novel dual modulation strategy of trigeminal pathway may provide additional therapeutic effects of pain symptoms in HZO population.

Dual neuromodulation strategy for pain management of herpes zoster ophthalmicus is proposed, with regard to stimulation site (peripheral and trigeminal ganglion) and apparatus (electrical nerve stimulation and pulsed radiofrequency).Superior clinical outcome was associated with novel neuromodulation therapy with dual therapeutic targets, when compared with peripheral nerve stimulation in treatment of herpes zoster ophthalmicus.We conducted literature review to compare distinct pattern of neuromodulation (peripheral nerve stimulation and radiofrequency) in treatment of trigeminal neuropathic pain caused by herpes zoster.

Ultrasound-guided percutaneous puncturing technique: novel radiofrequency ablation technique for thoracic sympathectomy in the treatment of palmar hyperhidrosis.

Radiofrequency thoracic sympathectomy is routinely conducted under computed tomographic or fluoroscopic guidance in the treatment of palmar hyperhidrosis. However, it remains a great challenge to perform a thoracic paravertebral puncture precisely and safely, because it is associated with repeated exposure to radiation and the risk of a pneumothorax. Alternatively, an ultrasound-guided technique can provide high-resolution and real-time needle tracking during the percutaneous procedure. We have provided our experience of ultrasonic guidance in radiofrequency sympathectomy for the treatment of primary palmar hyperhidrosis.

Ultrasound-guided percutaneous laser cervical discectomy for intractable hiccups: A rare case report.

Background: Intractable hiccups serve no physiological purpose, but significantly reduce the quality of life. There are a variety of medications suggested for the treatment of persistent or intractable hiccups. However, it remains a great challenge for the management of intractable hiccups. In this case report, we describe the technique of percutaneous laser cervical discectomy under the sonographic guidance in treatment of intractable hiccups. Case description: A 41-year-old male, who suffered intractable hiccups over 11 years, came to our pain department in December 2020. Neither oral medication nor phrenic nerve block achieved satisfactory relief of hiccups. Magnetic resonance imaging and computed tomography scan revealed cervical disc herniation of C4/5 and C5/6. Following selective cervical nerve root block, complete but short-term control of symptoms lasted less than 48 hours. Percutaneous laser cervical discectomy was then performed under ultrasound guidance and achieved complete and enduring symptomatic relief up to 14-month follow-up. Conclusion: Cervical degenerative changes may be considered as potential cause for intractable hiccups, and ultrasound-guided percutaneous laser cervical discectomy may be used to treat hiccups caused by cervical discogenic etiology.

PainVision-based evaluation of brain potentials: a novel approach for quantitative pain assessment.

Introduction: The complex and multidimensional nature of pain poses a major challenge in clinical pain assessments. In this study, we aimed to evaluate a novel approach combining quantitative sensory testing (QST) with event-related potential measurements for assessment of experimental pain in healthy individuals. Methods: QST was performed with a commercial device (PainVision, PS-2100), and numeric rating scale (NRS) scores after exposure to different sensory stimuli were reported by the participants. Resting-state electroencephalography (EEG) was simultaneously performed to capture the cortical responses to peripheral stimulation. Results: Pain scores increased with the intensity of stimuli, with mean NRS scores of 2.7 ± 1.0 after mild stimuli and 5.6 ± 1.0 after moderate stimuli. A reproducible, significant P2-N2 complex was evoked by both mild and moderately painful stimuli, but not by non-painful stimuli. The latency of pain-related potentials was not significantly different between stimuli. The amplitudes of both P2 and N2 components significantly increased when intense nociception was applied, and the increments mainly originated from theta oscillations. Conclusion: The combination of QST with EEG was feasible for subjective and objective pain assessment. Distinct patterns of brain potentials were associated with the phenotype of the peripheral stimuli (e.g., noxious versus. innoxious, high versus. low pain intensity).

Photic sensitization is mediated by cortico-accumbens pathway in rats with trigeminal neuropathic pain.

Exposure to light stimuli may trigger or exacerbate perception of pain, also known as a common yet debilitating symptom of photophobia in patient with chronic orofacial pain. Mechanism underlying this phenomenon of photic sensitization in neuropathic condition remains elusive. Here, we found that rats developed hypersensitivity to normal light illumination after establishment of chronic constriction injury of infraorbital nerve (ION-CCI) model, which can be attenuated by blocking the exposure of photic stimulation. Additionally, this behavioral phenotype of light-sensitivity impairment was associated with overexpression of anterior cingulate cortex (ACC) c-fos positive neurons, enhancement of neural excitability in the ACC neurons and its excitatory synaptic transmission between nucleus accumbens (NAc). Optogenetic and chemogenic silencing of ACC-NAc pathway improved trigeminal sensitization in responses to light stimuli by decreasing spontaneous pain-like episodes in ION-CCI animals. In contrast, selective activation of ACC-to-NAc circuits enhanced photic hypersensitivity in dark environment. Thus, our data provided novel role of ACC and its projection to NAc in bidirectional modulation of photic sensation, which may contribute to the understanding of photic allodynia in trigeminal neuropathic pain status.

A Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate the Therapeutic Effect of Magnesium-L-Threonate Supplementation for Persistent Pain After Breast Cancer Surgery.

Purpose: Post-mastectomy pain syndrome is a common yet debilitating neuropathic complication after breast cancer procedures, resulting in significantly reduced quality of life. Recently, emerging evidence has supported the therapeutic effect of magnesium administration in chronic pain. However, the role of magnesium supplementation in development of chronic pain after breast cancer surgery remains less known. The aim of this study was to evaluate therapeutic effect of magnesium supplementation on persistent pain after breast cancer procedure. Patients and Methods: This was a randomized, double-blind, placebo-controlled clinical trial. A total of 109 patients who underwent breast cancer procedure received magnesium-L-threonate (n = 48) or placebo (n = 61) for 12 weeks. Chronic pain incidence, short form of the McGill Pain Questionnaire (SF-MPQ), Generalized Anxiety Disorder Scale (GAD-7), Patient Health Questionnaire-9 (PHQ-9), Pittsburgh Sleep Quality Index (PSQI), and Telephone Interview for Cognitive Status (TICS) were evaluated at 3- and 6-month follow-up. Results: About 31% (15 out of 48) of patients reported chronic pain after magnesium supplementation, and 26% (16 out of 61) of the control group at 6-month follow-up respectively. Total scores of SF-MPQ were significantly increased in the control group 6 months after surgical intervention (mean difference, 1.475; 95% CI, -2.730 to -0.2211), but NOT in the magnesium treated group (mean difference, 1.250; 95% CI, -2.775 to 0.2748). No significant differences were found between two cohorts on SF-MPQ, GAD-7, PHQ-9, PSQI, or TICS at each timepoint. Conclusion: Oral supplementation of magnesium-L-threonate did not effectively prevent the development of persistent pain in breast cancer survivors, nor provide sufficient pain relief over placebo. We did not observe improvement of pain, mood, sleep disorder, or cognitive function after 12-week magnesium supplementation. Future study may focus on magnesium combined with other effective anti-neuropathic pain treatment.

Gadolinium-based MR cisternography with prepontine cisternal routine for evaluating distribution pattern of intrathecal targeted drug delivery in pain management.

Gadolinium-based MR cisternography has been mainly applied in clinical evaluation of cerebrospinal fluid leaking, that is conducted by intrathecal administration of contrast media. Recently, we have reported one novel technique of intrathecal targeted drug delivery with prepontine cisternal routine to treat orofacial cancer pain. The aim of this study was to examine the distribution pattern of this intrathecal drug delivery strategy. Here, we introduce one case who suffered severe orofacial pain caused by sublingual gland tumor, and successfully attenuated by prepontine cisternal administration of analgesic agents. To assess the distribution of intrathecal drugs, postoperative MR images of brain, cervical, thoracic, and lumbar segments in axial, coronal, and sagittal planes were obtained after application of gadolinium. The perfusion rate of contrast medium was set at 0.01 mmol per hour for 24 hours prior to MR scanning. In the T1-weighted images, we can identify contrast spread not only locating around the site of the intrathecal catheter tip, but also concentrated to the lateral sides. None obvious side effect was found after intrathecal injection of contrast media. Thus, our finding demonstrated the local distribution phenomenon of intrathecal drugs through prepontine cisternal access, and the bilateral perfusion pattern may provide insights underlying the analgesic mechanism of trigeminal pain provided by this novel intrathecal therapy. Gadolinium-based MR cisternography may serve as a potential tool to confirm the therapeutic effect of intrathecal targeted drug delivery via prepontine cisternal routine in orofacial pain management.

Electroencephalography Signatures for Hepatic Encephalopathy in Cirrhosis Patients Treated with Proton Pump Inhibitors: An Exploratory Pilot Study.

(1) Background: Hepatic encephalopathy (HE) is a common complication in cirrhosis patients, and recently, clinical evidence indicates that a higher risk of HE is associated with the usage of proton pump inhibitors. However, the cortical mechanism underlying this neurological disorder of HE remains unknown. (2) Methods: We review the medical recordings of 260 patients diagnosed with liver cirrhosis between January 2021 and March 2022 in one tertiary hospital. Logistic regression analyses were performed to identify the risk factor of HE development. To examine the relationship between cortical dynamics and the administration of proton pump inhibitors, resting-state electroencephalograms (EEGs) were conducted in cirrhosis patients who were treated with proton pump inhibitors. (3) Results: About 28.5% (74 out of 260) of participants developed secondary HE in this study. The logistics regression model indicated that multiple risk factors were associated with the incidence of secondary HE, including proton pump inhibitors usage, white blood cell and neutrophil counts, hemoglobin, prothrombin time activity, and blood urea nitrogen. A total of twelve cirrhosis patients who were scheduled to use proton pump inhibitors consented to performing electroencephalogram recordings upon admission, and eight of twelve participants were diagnosed with HE. Spectral analysis revealed that the decrease in alpha oscillation activities was potentially associated with the development of HE. (4) Conclusions: Our data support the susceptibility of secondary HE in cirrhosis patients treated by proton pump inhibitors. One potential cortical mechanism underlying the neurological disease is the suppression of alpha oscillations in the brain.

Prepontine cisternal routine for intrathecal targeted drug delivery in craniofacial cancer pain treatment: technical note.

Intrathecal targeted drug delivery provides effective relief for cancer-related pain. However, its validation in management of craniofacial pain remains much less widely practiced, mainly due to the localized diffusion of analgesic agent with current approach. Here, we report our experience of prepontine cisternal routine for placement and implantation of intrathecal targeted drug delivery in two cases of cancer-related craniofacial pain. Lumbar cannulation was applied and the intrathecal catheter tip was positioned at the prepontine cistern under fluoroscopic guidance during the surgical implantation. Postoperative imaging confirmed that the catheter tip was successfully placed in the prepontine cisternal space. Satisfactory control of pain was achieved after intrathecal therapy, with significant reduction of background and breakthrough cancer pain. None obvious complications were observed in this study. Thus, our novel intrathecal routine may provide an alternative option for craniofacial pain caused by tumor, who were insufficiently treated by oral analgesic agents.

Effect of Implantable Electrical Nerve Stimulation on Cortical Dynamics in Patients With Herpes Zoster-Related Pain: A Prospective Pilot Study.

Implantable electrical nerve stimulation (ENS) can be used to treat neuropathic pain caused by herpes zoster. However, little is known about the cortical mechanism underlying neuromodulation therapy. Here, we recorded a 16-channel resting-state electroencephalogram after the application of spinal cord stimulation (n = 5) or peripheral nerve stimulation (n = 3). The neuromodulatory effect was compared between specific conditions (active ENS versus rest). To capture the cortical responses of ENS, spectral power and coherence analysis were performed. ENS therapy achieved satisfactory relief from pain with a mean visual analog scale score reduction of 5.9 ± 1.1. The spectral analysis indicated that theta and alpha oscillations increased significantly during active neuromodulation compared with the resting state. Furthermore, ENS administration significantly increased frontal-frontal coherence in the alpha band. Our findings demonstrate that, despite methodological differences, both spinal cord and peripheral nerve stimulation can induce cortical alpha oscillation changes in patients with zoster-related pain. The dynamic change may, in part, mediate the analgesic effect of ENS on herpes zoster-related pain.

Feasibility study of ultrasound-guided percutaneous laser discectomy for cervical radicular pain.

Percutaneous laser discectomy is one common and effective treatment for cervical radicular pain. Currently, the surgery is performed with blind cannulation technique, mainly relies on the experience of surgeon. However, it still remains unsafe and difficult to reach the target. As an alternative, ultrasound-guided cannulation provides visualization of important structures, thus increasing the precision and safety. The primary goal of this study is to report the detail of the ultrasound-guided technique in the percutaneous laser cervical discectomy. The secondary purpose is to evaluate the feasibility of the novel therapy. This is a single center, feasibility study conducted in one teaching hospital. Thirteen intervertebral discs in 9 patients presented with cervical radicular pain. Accuracy of the cannulation with ultrasonic guidance was confirmed by the anterior-posterior and lateral view of fluoroscopy. We compared the pain severity pre- and post-treatment with Visual Analogue Score (VAS), and functional improvement was assessed with the modified Macnab Criteria and Neck Disability Index (NDI) respectively. Ultrasonic short-axis was used to scan the cervical nerve root, and its transition was used to identify the distinct intervertebral space. Following the recognition of targeted cervical level, the ultrasound probe was moved medially for the visualization of the surface of the cervical vertebrae. In plane cannulation was then applied to avoid the injury of the vessels. The location of cannula was confirmed by the fluoroscopic imaging. Low-power laser was set for the cervical disc ablation in this cohort. The majority of the surgical sites maintained in the C5/6 level (38%), and 31% for the C6/7 level respectively. Despite the distinct cervical level, the tip of needle was properly placed near by the targeted intervertebral disc in all participants, which was confirmed by the imaging of fluoroscopy. We did not observe any obvious complications during the procedure. The mean VAS decreased from 7.6 ± 1.1 to 2.3 ± 2.7 one month after discharge, and 2.1 ± 2.6 at the last follow-up (median duration of nine months). All patients reported significant improvement of NDI up to last follow-up (p = 0.011). Meanwhile, the good to excellent rate was reported in 8 of 9 patients (89%) according to the modified Macnab Criteria. The finding of this feasibility assessment indicates the ultrasound-based cannulation technique is capable of guiding the cannulation for the percutaneous laser discectomy. It may facilitate identifying the corresponding site of cervical intervertebral disc and prevent the damage of vessel.

A novel implantable device for sensory and affective assessment of orofacial pain in rats.

Background and objective: Orofacial pain, in particular, chronic orofacial pain remains a great challenge in clinical practice. To better understand the underlying mechanism of disease, it is essential to apply a feasible and stable preclinical measurement of facial pain. Here, we introduced a novel electrical noxious stimulator in freely behavioral rodents and examined its validation in both naïve and chronic orofacial pain animals. Methods: One subcutaneous device of electrical stimulator was implanted in the facial region for delivery of the nociceptive input. The sensory component of orofacial pain was assessed by response scoring tool, and conditioned place aversion (CPA) paradigm for pain affect respectively. To confirm its usage in chronic pain state, the chronic constriction injury of the infraorbital nerve (ION-CCI) model was then applied. Results: We found that responsive scores increased with stimulation intensity, and acted in a dosage-dependent manner, which can be attenuated by the administration of morphine intraperitoneally. Naïve rats displayed significant aversive reaction to the noxious electrical stimulation (25V) in the CPA testing. In addition, an obvious sensory hypersensitivity to electrical stimulation was confirmed by the increased response scores in ION-CCI rats. Furthermore, ION-CCI animal showed significant avoidance to electrical stimulation at relatively low intensity (10V), which was innoxious to naïve rats. Conclusion: Our findings may provide an alternative pre-clinical measurement of orofacial pain, to quantitively assess both sensory and affective component of orofacial pain.