Nerve Path Research Articles

Use of Magnetic Resonance Neurography for Sensory Nerve Injuries of the Head and Neck.

Identification of peripheral nerve injuries of the head and neck can be challenging due to a broad spectrum of symptoms from neuropathic pain to headaches and migraine. This article aimed to present the clinical features and diagnostic workup of patients with acute and chronic peripheral nerve injuries of the head and neck using magnetic resonance neurography (MRN), to demonstrate potential advantages compared with conventional magnetic resonance imaging (MRI). Patients who presented with suspected peripheral nerve injury were either referred for a conventional MRI or MRN. Patients who underwent nerve exploration for suspected nerve transection and/or neuroma formation on imaging were included in this study. Imaging findings were correlated with intraoperative observations. Four patients (3 women, 1 man, age range: 34-70 years) were included. Three subjects had a history of head and neck surgery and 1 experienced direct trauma to the medial eyebrow. Clinical symptoms included numbness, allodynia, positive Tinel sign, and pain relief following nerve blocks. Two patients underwent conventional MRI and 2 underwent MRN. MRI provided a vague indication of potential neuromas and failed to accurately depict their locations. MRN offered a comprehensive visualization of the entire nerve path, identifying nerve transection and neuromas, as well as precise location, dimensions, and relation to adjacent bones and muscles. High-resolution 3-dimensional MRN provides clear visualization of acute and chronic peripheral nerve injuries of the head and neck region, facilitating early diagnosis of nerve injuries in this region and improving diagnostic accuracy, as well as surgical planning and execution.

Effectiveness of the scapula mobilization technique on the neural mechanosensitivity of the upper limb neural test 1 in individuals with mechanical cervicalgia. A randomized controlled trial

Objectiveto observe whether the mobilization of the scapula improves the mechanosensitivity of the median nerve in patients with cervicalgia. Localized cervical pain caused by compression of a nerve root without presenting irradiated features along the nerve path is diagnosed as cervicalgia. Muscles around the scapula can be directly responsible of this compression. Methods60 adults diagnosed with cervicalgia and with a positive upper limb neural test 1(ULNT1) were recruited. Participants in the experimental group received a scapula mobilization technique. Participants in the control group, with electrodes on both sides of the neck and connected to turned off analgesic current device, received an abduction-adduction mobilization of the calcaneus in the lower limb contralateral to the painful area. The variables measured were pain, goniometry of elbow extension in movement for the median neurodynamic test (ULNT1) and hand grip strength. ResultsResults showed that the increase in strength (p = 0.01) and elbow extension movement (p = 0.01) and the decrease in pain (p < 0.01) from the intervention group showed significant changes compared to the changes from control group. ConclusionScapula mobilization technique in subjects presenting with cervicalgia and a positive ULNT1 significantly appears to help improve the neural mechanosensitivity of the median nerve and pain.

Intra-parotid facial nerve path by MRI tractography: radio-clinical comparison in parotid tumors.

The objective of our study was to evaluate the ability of preoperative MRI tractography to visualize and predict the path of the facial nerve with respect to an intra-parotid mass. We performed an observational bicentric study from June 2019 to August 2020. All patients older than 18years old, treated for a parotid mass with surgical indication, without MRI contraindication and who agreed to participate in the study were enrolled prospectively. All patients underwent a cervico-facial MRI with tractographic analysis. Postprocessed tractography images of the intra-parotid facial nerve were analyzed by two expert radiologists in head and neck imaging. The intraoperative anatomical description of the facial nerve path and its relationship to the mass was performed by the surgeon during the operation, with no visibility on MRI examination results. A statistical study allowed for the description of the data collected as well as the measurement of inter-observer agreement and agreement between tractography and surgery using kappa coefficients. Fifty-two patients were included. The facial nerve trunk and its first two divisional branches were visualized via tractography in 93.5% of cases (n = 43). The upper distal branches were visualized in 51.1% of cases (n = 23), and the lower branches were visualized in 73.3% of cases (n = 33). Agreement with the location described per-operatively was on average 82.9% for the trunk, 74.15% for the temporal branch, and 75.21% for the cervico-facial branch. Fiber tractography analysis by MRI of the intra-parotid facial nerve appears to be a good test for predicting the path of the nerve over the parotid mass and could be an additional tool to guide the surgeon in the operative procedure.

Cone-Beam Computed Tomography Assessment of Bifid and Trifid Mandibular Canals: A Cross-Sectional Study

The exact knowledge of the mandibular canal position is fundamental in oral surgery and implantology. Clinicians have to be extremely cautious when operating in close proximity to this structure in order to avoid damaging the neurovascular bundle. Several anatomical variations of the mandibular canal have been described in the literature, such as bifid or trifid structures. The use of cone-beam computed tomography (CBCT) offers a detailed representation of the inferior alveolar nerve path, albeit with some difficulties of identification when dental implants or metal prosthesis are present. The aim of this study is to retrospectively evaluate the prevalence and location of bifid/trifid mandibular canals (BMC/TMC) by CBCT in Italian patients. The screening phase involved 584 patients, only 238 enrolled (97 men; 141 women), with an average age of 51 ± 17.20. A total of 36 patients (15.25%) showed at least one bifid mandibular canal; only 2 patients (0.84%) showed a trifid mandibular canal. Overall, 12 patients (5.04%) presented this variation bilaterally. There was no association with the sex of the enrolled sample. In conclusion, the presence of BMCs and TMCs may be considered as a risk factor for the onset of neurovascular complications. Being aware of changes in the mandibular canal helps clinicians to prevent inferior alveolar nerve impairments that may occur during oral surgery and implantology.

An Artificial Reflex Arc That Perceives Afferent Visual and Tactile Information and Controls Efferent Muscular Actions.

Neural perception and action-inspired electronics is becoming important for interactive human-machine interfaces and intelligent robots. A system that implements neuromorphic environmental information coding, synaptic signal processing, and motion control is desired. We report a neuroinspired artificial reflex arc that possesses visual and somatosensory dual afferent nerve paths and an efferent nerve path to control artificial muscles. A self-powered photoelectric synapse between the afferent and efferent nerves was used as the key information processor. The artificial reflex arc successfully responds to external visual and tactile information and controls the actions of artificial muscle in response to these external stimuli and thus emulates reflex activities through a full reflex arc. The visual and somatosensory information is encoded as impulse spikes, the frequency of which exhibited a sublinear dependence on the obstacle proximity or pressure stimuli. The artificial reflex arc suggests a promising strategy toward developing soft neurorobotic systems and prostheses.

Effectiveness of Laser Therapy and Laser Acupuncture on Treating Paraesthesia After Extraction of Lower Third Molars

Objective: This randomized clinical trial evaluated the sensitive return of the lower alveolar nerve (LAN) using two photobiomodulation therapy (PBMT) techniques, after the extraction of lower third molars or implant surgery. Materials and methods: Sixty participants with sensory impairment of LAN were randomly divided into three groups (n = 20): group C-systemic medication (control-ETNA®, 01 capsule, 8/8 h, 30 days); group laser therapy (LT) (808 nm, 100 mW, 40 sec/point, 4 J/point, intra/extraoral, irradiation following nerve path); group laser acupuncture (LA) (same parameters as the LT group, applied at six acupuncture points on the affected side (ST 4 [Dicang], M-HN-18 [Jiachengjiang], CV 24 [Chengjiang], ST 5 [Daying], ST 6 [Jiache], and point A1 [YNSA]). The following evaluations were performed, at predetermined times: general perception of paresthesia, thermal perception, vibratory mechanical perception, two-point discrimination, pain perception, and tactile perception. Data were analyzed by two-way analysis of variance (ANOVA), followed by the Tukey, except for the two-point discrimination, which was analyzed using the chi-square test. Results: In general and thermal perception, both PBMTs had better results than control; regarding cold perception, only the LT group was statistically superior to control. LA presented inferior results of neural regeneration for tests of perception of pain and tactile at the lip, and of tactile perception at the chin. In the other tests, there was no statistical difference among the groups. Conclusions: LT and the conventional drug treatment had the same effectiveness and both were superior to LA for the treatment of paresthesia of the LAN after oral surgeries.

Anatomical variation of the saphenous nerve path: A case report

The saphenous nerve has great importance on the sensitivity of the lower limb. In its normal course, it enters the adductor canal and travels under the sartorius muscle, on the medial side of the thigh. The anatomical variation was found accidentally during routine cadaveric dissection of the thigh at the Human Anatomy Laboratory of the Department of Morphophysiology of the Faculty of Medical Sciences of Minas Gerais (FCMMG). A different pattern of path of the saphenous nerve was found, which appears to perforate the sartorius muscle. Complaints of pain in the lower limbs are highly prevalent in the adult population. Saphenous neuropathy is a pathological entity that is associated with such a clinic and may have compression or trauma as its etiology. In the context of compression, it can be caused due to the unusual nerve path, as described in the present study. In trauma, knowledge of this variation is important to prevent iatrogenic damage to nervous tissue during surgical procedures. The anatomic variation presented may be related to the symptom of pain in the lower limbs and is also relevant in the surgical context, in order to prevent complications.

Effectiveness and safety of warm needle acupuncture for sciatica: A protocol for systematic review and meta-analysis.

Background:Sciatica is a syndrome characterized by sciatic nerve path and distribution area pain. Many kinds of literature reported the definite effect of warm needle acupuncture (WNA) on sciatica. However, there is no systematic review or meta-analysis on WNA for sciatica. Therefore, this study will design a protocol to comprehensively and systematically evaluate the effectiveness and safety of WNA on sciatica.Methods:The two researchers in this study will search the electronic database for randomized controlled trials, (RCTs) of WNA on sciatica, The databases we will search include PubMed, EMBASE, Cochrane Library, Web of Science, Chinese national knowledge infrastructure (CNKI), China Science and Technology Journal Database (VIP), Wanfang Database, and Chinese biomedical literature database (CBM). Review Manager 5.4 software and Cochrane risk bias tool will be us used for data analysis and to evaluate research quality. The main clinical indicators will include visual analogue scale (VAS) and Oswestry Disability Index (ODI).Results:This study will evaluate the efficacy and safety of WNA for sciatica.Conclusion:This study will provide a reliable scheme for objectively and comprehensively evaluating the efficacy and safety of WNA on sciatica.Trial registration number:INPLASY2020110074

A 3D ontogenetic atlas of Alligator mississippiensis cranial nerves and their significance for comparative neurology of reptiles.

Cranial nerves are key features of the nervous system and vertebrate body plan. However, little is known about the anatomical relationships and ontogeny of cranial nerves in crocodylians and other reptiles, hampering understanding of adaptations, evolution, and development of special senses, somatosensation, and motor control of cranial organs. Here we share three dimensional (3D) models an of the cranial nerves and cranial nerve targets of embryonic, juvenile, and adult American Alligators (Alligator mississippiensis) derived from iodine-contrast CT imaging, for the first time, exploring anatomical patterns of cranial nerves across ontogeny. These data reveal the tradeoffs of using contrast-enhanced CT data as well as patterns in growth and development of the alligator cranial nervous system. Though contrast-enhanced CT scanning allows for reconstruction of numerous tissue types in a nondestructive manner, it is still limited by size and resolution. The position of alligator cranial nerves varies little with respect to other cranial structures yet grow at different rates as the skull elongates. These data constrain timing of trigeminal and sympathetic ganglion fusion and reveal morphometric differences in nerve size and path during growth. As demonstrated by these data, alligator cranial nerve morphology is useful in understanding patterns of neurological diversity and distribution, evolution of sensory and muscular innervation, and developmental homology of cranial regions, which in turn, lead to inferences of physiology and behavior.

A CBCT Based Three-Dimensional Assessment of Mandibular Posterior Region for Evaluating the Possibility of Bypassing the Inferior Alveolar Nerve While Placing Dental Implants.

A high rate of nerve injury and related consequences are seen during implant placement in the posterior mandibular arch. An approach has been proposed to avoid nerve injury by dodging the inferior alveolar nerve (IAN) while placing an implant. A prospective study with a total of 240 CBCT (cone beam computed tomography) images of patients with three dentate statuses, namely, edentulous (group I), partially edentulous (group II) and dentate (group III) were included in the study. The nerve path tracing was done on CBCT images with On-demand 3D software. The three dimensions, i.e., the linear distance from the outer buccal cortical plate to the inferior alveolar nerve (BCPN), linear distance from the outer lingual cortical plate to the inferior alveolar nerve (LCPN) and linear distance from the midpoint of the alveolar crest to the inferior alveolar nerve (ACN) were assessed. The data were presented and analyzed between variables using one-way ANOVA and independent t-test in SPSS version 21.LCPN of the right 1st premolar region (p < 0.05) was significantly different among the groups with edentulous subjects recorded with the minimum value (6.50 ± 1.20 mm). Females were found to have significantly (p < 0.05) less available bone (6.03 ± 1.46 mm) on the right side of the mandibular jaw compared to males in edentulous group of patients. On comparing age groups for partially edentulous subjects, LCPN of the right 1st premolar region had significantly (p < 0.05) less available bone (6.03 ± 0.38 mm) in subjects with age ≥54 years. The IAN follows a lingual course in the molar region and later flips to the buccal side in the premolar region. The LCPN dimension in the 1st and 2nd premolar region was found to be more than 6 mm irrespective of age, gender and side of the jaw. Thus, it can be considered as a suitable site for placing implants while bypassing the IAN with CBCT assessment remaining as the mainstay in the pre-surgical phase.

Low-level laser therapy for neurosensory recovery after sagittal ramus osteotomy.

Dento-skeletal deformities are treated combining orthodontic treatment with orthognathic surgery. One of the techniques most used in this type of surgery is the sagittal osteotomy of the mandible. This technique offers many advantages, but within its disadvantages is the inferior alveolar nerve paresthesia. There are various treatments that aim to recovery of the nerve bundle, and one of them is low intensity laser treatment. The aim of this study was to evaluate the effectiveness of low intensity laser therapy in the recovery of neurosensorial tissues after mandibular sagittal osteotomy during orthognathic surgery. Twelve patients submitted to surgery, using mandibular sagittal osteotomy, were treated unilaterally with low intensity infrared (808 nm, GaAIAs active medium) laser, following the inferior alveolar nerve path. The other part of the mandible was treated by placebo. The parameters used were 100 mW of power, irradiancy of 3.6 W/cm2, 2.8J energy per point, an energy density of 100 J/cm2, 28 seconds at each point with a distance of 1.0 cm between points, two sessions per week with a minimum of 10 sessions, starting 48 hours after surgery. Mechanical evaluation was performed in first, fourth, seventh and tenth session. Significant improvement on the treated side was observed. Comparing the behavior among the variables between the treatment (T) group and the control (C) group in the General Recovery was showed a tendency to better results in the T group when compared to the C group, with statistical difference (P≤0.05) after the 10th laser therapy session. The treatment of neurosensorial disorders with infrared low intensity laser could be effective in accelerating recovery, providing greater comfort to the patient, and it presents advantages over other existing methods.

Burkholderia pseudomallei invades the olfactory nerve and bulb after epithelial injury in mice and causes the formation of multinucleated giant glial cells in vitro.

The infectious disease melioidosis is caused by the bacterium Burkholderia pseudomallei. Melioidosis is characterised by high mortality and morbidity and can involve the central nervous system (CNS). We have previously discovered that B. pseudomallei can infect the CNS via the olfactory and trigeminal nerves in mice. We have shown that the nerve path is dependent on mouse strain, with outbred mice showing resistance to olfactory nerve infection. Damage to the nasal epithelium by environmental factors is common, and we hypothesised that injury to the olfactory epithelium may increase the vulnerability of the olfactory nerve to microbial insult. We therefore investigated this, using outbred mice that were intranasally inoculated with B. pseudomallei, with or without methimazole-induced injury to the olfactory neuroepithelium. Methimazole-mediated injury resulted in increased B. pseudomallei invasion of the olfactory epithelium, and only in pre-injured animals were bacteria found in the olfactory nerve and bulb. In vitro assays demonstrated that B. pseudomallei readily infected glial cells isolated from the olfactory and trigeminal nerves (olfactory ensheathing cells and trigeminal Schwann cells, respectively). Bacteria were degraded by some cells but persisted in other cells, which led to the formation of multinucleated giant cells (MNGCs), with olfactory ensheathing cells less likely to form MNGCs than Schwann cells. Double Cap mutant bacteria, lacking the protein BimA, did not form MNGCs. These data suggest that injuries to the olfactory epithelium expose the primary olfactory nervous system to bacterial invasion, which can then result in CNS infection with potential pathogenic consequences for the glial cells.

Neuralgias

Cranial neuralgias are an uncommon but very disabling condition caused by neurovascular compression in cranial nerve. In neuralgia, pain appears and disappears suddenly, crosses all nerve path and its duration is short. Usually are triggered by innocuous stimuli. No apparent causes or underlaying disorders may be involved in its pathophysiology. Carbamazepine continues being the medical treatment of choice. Sodium-channel blockers, like lamotrigine and botulinum toxin, are other therapeutic agents. Non-ablative surgery, like Jannetta procedure, is a therapeutic alternative as well as the decompression of the Gasserian ganglion or the trigeminal trunck exit.

Sensibilité de l’hémipulpe radiale de l’index — étude des tests de Semmes-Weinstein versus Cochet-Bonnet chez 25 sujets sains

In the presence of a wound to the palm, several methods of evaluation of the cutaneous sensitivity were proposed to search for sensory deficits. Some authors have shown that the sensitivity and specificity of any other test do not reach 100%. Most authors consider that any hand wound in the vicinity of a nerve path must be surgically explored. The purpose of this work was to verify whether the Cochet-Bonnet corneal sensitivity test had a lower cutaneous pulp sensitivity threshold than the Semmes-Weinstein monofilament test. The series included 25 healthy adult subjects. The average age was 30 years old. All were right-handed except one left-handed. None had a history of a medical or surgical pathology of upper limbs. The protocol consisted of evaluating the tactile cutaneous sensitivity threshold of the radial collateral hemi-pulp of the index finger by an independent observer using two tests, the Semmes-Weinstein esthesiometer and the Cochet-Bonnet. The Semmes-Weinstein test consisted of determining the finest monofilament perceived from a kit of 20 calibrated monofilaments from 0.0045 to 447.0 g. The monofilaments were applied one after the other perpendicularly to the hemi-pulp so that the wire bends slightly for 1.5 seconds. The Cochet-Bonnet test consisted of determining the longest perceived monofilament from a 12-length calibrated pen from 0.006 to 0.618 g. The monofilament was applied perpendicularly to the hemi-pulp so that the thread bent slightly for 1.5 seconds. The sensitivity threshold of the radial hemi-pulp of the index was lower with the CB test than with the SW test. The average cutaneous sensitivity threshold of the hemi-pulps of our series was 0.0388 g, which corresponds to the threshold of 0.035 g before 35 years found in the literature. Our results show that in healthy subjects, the threshold of sensitivity of the radial hemi-pulp of the index is lower with the Cochet-Bonnet monofilament test than with the Semmes-Weinstein monofilament test. The material needed to carry out the Cochet-Bonnet monofilament test is cheaper (424 €) and less cumbersome (1 monofilament) than that required for the Semmes-Weinstein monofilament test, which costs more (901 €) and is bulkier (20 monofilaments). It remains to test the sensitivity and specificity of the CB test on wounds of the palm to check the absence of nerve damage.

T110. Visualization of nerve impulse traveling along the brachial plexus after ulnar nerve stimulation using magnetoneurography system

Introduction In somatosensory evoked potential (SEP) testing, an analysis of Erb’s potentials following median or ulnar nerve stimulation at the wrist may be useful to define a lesion of the lateral cord or the medial cord of the brachial plexus (BP) neuropathy. However, there have been few SEP studies on multiple site recording of Erb’s potentials so that traveling nature of the nerve impulse along BP has not been visualized yet. By analysis of magnetoneurogram with superconducting quantum interference device (SQUID) sensor system, we succeeded in visualizing the nerve impulse traveling along BP and then propagating into the C5–C8 intervertebral foramen after median nerve stimulation. Here we aimed to analyze the nerve impulse traveling along BP following ulnar nerve stimulation at the wrist. Methods Magnetoneurogram over BP of 5 healthy volunteers (Age range, 25–45 years; mean, 32.8 y.o) were measured after ulnar nerve stimulation (supramaximal stimulus; 5 Hz and averaging 2000 responses) using a newly developed 132 channel SQUID biomagnetometer with an X-ray imaging system (RICOH COMPANY, Ltd., Tokyo, Japan). At the same time, SEP was measured at Erb’s point using MEB-2300 (Nihon Kohden Corporation, Tokyo, Japan) for making sure to deliver supramaximal stimulation. After magnetoneurogram recording, evoked action currents were computationally reconstructed by a spatial filter method and the estimated electric currents map was superimposed over X-ray images. Results We were able to record the magnetic fields over the brachial plexus with good signal quality after ulnar nerve stimulation. Distribution of neural activity currents in the brachial plexus were estimated from the measured magnetic fields and visualized over X-ray images in all subjects. The currents distribution showed axonal activity pattern and passed medially to the coracoid process, crossed the clavicle, and reached the C7 - Th1 intervertebral foramen along the nerve path in the period between 8.0 ms and 13.0 ms after the stimulation. The conduction velocity calculated using the peak latency of the estimated current waveform on the nerve path was 67.13 ± 1.96 m/s. Conclusion By analysis of magnetoneurogram with participants’ X-ray image of the upper thorax,we succeeded in visualizing the nerve impulse traveling along (possibly) the medial cord of BP and then propagating into the C7 – Th1 intervertebral foramen after ulnar nerve stimulation at the wrist. Together with our previous study on magnetoneurogram after median nerve stimulation, we consider magnetoneurogram testing as superior to conventional SEP for analyzing the conductive function of BP because the former enables us to evaluate the conductive function of the nerve from the lateral or medial cord of BP to C5 – Th1 intervertebral foramen after median or ulnar nerve stimulation. We propose that the method of magnetoneurograph with the X-ray image can provide useful information for the non-invasive diagnosis of localization of conduction block in BP neuropathy.

Effects of photobiostimulation in the treatment of post-herpetic neuralgia: a case report

Abstract Objectives: to describe the effect of photobiomodulation therapy in the treatment of post-herpetic neuralgia in the elderly. Case report: a female patient, 61 years old, 56 kg, 1.67cm tall, sought treatment at the Laser Therapy Center of the Universidade do Vale do Paraíba, in the city of São José dos Campos, São Paulo, Brazil, on October 27, 2015. She had been diagnosed with herpes zoster on September 4, 2015 with complaints of intermittent neuralgia in the long thoracic nerve path and spikes of intense pain (level 10, according to the analogue pain scale). Photobiomodulation was performed with low intensity laser spot irradiations at 20 points around the herpesvirus nerve, with a distance of 2cm between each point. Irradiation was performed at each point after 20 seconds, with 3J/cm2 per point and total energy of 60 J. At the end of the treatment the pain level was 0 and the patient exhibited a normal sleep pattern (8 hours of sleep). Conclusions: Photobiomodulation treated painful discomfort, improved the quality of life of the patient and proved to be an effective, safe and promising treatment, with significant potential to become the therapy of choice in such cases.

Feasibility of eliciting the H reflex in the masseter muscle in patients under general anesthesia.

To explore the feasibility of eliciting the brainstem H reflex in the masseter muscle in patients under general anesthesia. We electrically stimulated the masseteric nerve, a branch of the trigeminal nerve, and recorded ipsilateral masseteric and temporalis muscle responses. We tested eight patients who presented with trigeminal neuralgia; one patient had a temporal bone tumor and one patient had a brainstem arteriovenous malformation. All responses were elicited when patients were under general anesthesia and before the initiation of surgery. The H reflex in the masseter muscle was reliably elicited in 70% of the patients. The reflexes met the usual criteria for the H reflex because they were elicited below the threshold of the direct M response, and their amplitudes decreased when the M response increased with stronger stimuli. The mean onset latencies of the masseter H reflex and the M response were 5.4±1.3ms and 2.6±0.6ms, respectively. In the present study, we provide evidence of the feasibility of eliciting the H reflex in the masseter muscles of patients under general anesthesia. The H reflex of the masseter muscle may represent a new method available for intraoperative monitoring. Specifically, this method may be important for the monitoring of brainstem functional integrity, particularly in the midbrain and mid-pons, in addition to the trigeminal nerve path.

Introduction of a novel ultrasound-guided extrathoracic sub-paraspinal block for control of perioperative pain in Nuss procedure patients

BackgroundA safe and effective method of multilevel thoracic pain control remains an elusive goal in patients undergoing the Nuss procedure. The aim of our study was to develop a nonopioid centered approach using a novel regional technique as part of a quality improvement initiative. MethodsThe proposed ultrasound-guided technique positions multi-perforated soaker catheter deep to the paraspinal muscles from T2 to T11. The project was conducted in two phases. First, a cadaveric dissection was performed to establish the pathway of spread of local anesthetic in vivo. Second, a pilot double blind randomized control project was conducted to evaluate effectiveness of the technique in ten patients and to derive parameters necessary for the definitive future study. Outcomes were evaluated based on the narcotic requirement, pain scores and functional measures. ResultsPlacement of the catheters in two cadavers demonstrated reliable positioning in the subparaspinal tissue plane, and multilevel dye spread along the intercostal nerve path. In addition, a potential route of spread toward the paravertebral space along the canal accommodating dorsal ramus of the thoracic nerve was demonstrated. The pilot trial demonstrated a trend in decreased cumulative hydromorphone requirement in comparison to the control group at both 24h (0.19±0.09mg/kg vs. 0.13±0.08mg/kg p=0.72) and 48h (0.37±0.2mg/kg vs. 0.3±0.12mg/kg p=0.37). Functional performance ability was higher in the treatment group on both POD#1 (6.7±1.8 vs. 4.8±1 p=0.0495) and POD#2 (8.9±0.8 vs. 6.5±1.2 p=0.04). Pain scores were similar among the two groups (p=0.96). ConclusionsWe describe a new technique to treat multilevel thoracic pain following the Nuss procedure that is reproducible, safe, allows diminished opioid use and enhances functional recovery.

Anterior loop of the inferior alveolar nerve: Averages and prevalence based on CT scans

Statement of problemThe treatment of edentulous patients by using a complete implant-supported fixed prosthetic with distal extension has been widely studied; success is mainly dependent upon the placement of the distal implants. The location of the inferior alveolar nerve determines implant placement, but the length, prevalence, and symmetry between the left and right side of the anterior loop of the alveolar nerve are unknown. PurposeThe purpose of this clinical study was to measure the anterior loop of the inferior alveolar nerve, which determines the placement of distal implants, in a group of 55 Mexican participants. The study expected to ascertain the average length, prevalence, and symmetry between left and right side and any sex differences. To differentiate the inferior alveolar nerve path, a new technique was applied using Hounsfield unit (HU) thresholds. The null hypothesis was that no significant differences would be found between the left and right sides or between men and women for the anterior loop of the inferior alveolar nerve. Material and methodsFifty-five computed tomography (CT) scans were made (Somatom Sensation 16; Siemens Healthcare) and were visualized with InVesalius software. Anterior loop measurements were made on 3-dimensional surfaces. To determine statistical differences between the left and right side and between the sexes, the t test was used. The interclass correlation coefficient test was also applied to verify the reliability of the measurements. ResultsNinety percent of participants showed the anterior loop of the inferior alveolar nerve. The length of the anterior loop ranged between 0 and 6.68 mm, with a mean of 2.19 mm. No significant differences were found between the left and right sides or between men and women. ConclusionsThe mean length for the anterior loop in the sample was 2.19 mm. As the anterior loop length shows a high degree of variability, these findings suggest that a CT scan for each patient is recommended in order to visualize a safety zone before placing implants close to the mental foramen.

Preoperative transcutaneous electrical nerve stimulation for localizing superficial nerve paths

During surgery, peripheral nerves are often seen to follow unpredictable paths because of previous surgeries and/or compression caused by a tumor. Iatrogenic nerve injury is a serious complication that must be avoided, and preoperative evaluation of nerve paths is important for preventing it. In this study, transcutaneous electrical nerve stimulation (TENS) was used for an in-depth analysis of peripheral nerve paths. This study included 27 patients who underwent the TENS procedure to evaluate the peripheral nerve path (17 males and 10 females; mean age: 59.9 years, range: 18-83 years) of each patient preoperatively. An electrode pen coupled to an electrical nerve stimulator was used for superficial nerve mapping. The TENS procedure was performed on patients' major peripheral nerves that passed close to the surgical field of tumor resection or trauma surgery, and intraoperative damage to those nerves was apprehensive. The paths of the target nerve were detected in most patients preoperatively. The nerve paths of 26 patients were precisely under the markings drawn preoperatively. The nerve path of one patient substantially differed from the preoperative markings with numbness at the surgical region. During surgery, the nerve paths could be accurately mapped preoperatively using the TENS procedure as confirmed by direct visualization of the nerve. This stimulation device is easy to use and offers highly accurate mapping of nerves for surgical planning without major complications. The authors conclude that TENS is a useful tool for noninvasive nerve localization and makes tumor resection a safe and smooth procedure.