Normal Sensation Research Articles

Sensory assessment of intramuscular quadratus lumborum block at the L2 level in open inguinal hernia repair patients

BackgroundThe effectiveness of the quadratus lumborum block (QLB) for postoperative pain management depends on the injection pathway used. There is limited research on the block area produced by intramuscular injection of local anesthesia in the quadratus lumborum muscle. This study aimed to determine the cutaneous sensory blockade area produced by an intramuscular quadratus lumborum block (QLBi) at the L2 level.MethodsTwenty patients aged 18–60 years with ASA grade I-II and a BMI of 18–30 kg/m2 who were scheduled for open inguinal hernia repair with mesh underwent ultrasound-guided QLBi injection of 20 ml of 0.5% ropivacaine. The cutaneous sensory blockade area was measured by applying a cold stimulus 1 h after the block and then measured every hour after surgery until the sensation returned to normal. The duration of a blockade is defined as the time it takes for all affected areas to fully regain normal sensation following a blockade. Pain scores (numeric rating scale, NRS) were recorded at 2, 4, 8, 12, and 24 h after surgery. Adverse reactions to QLBi were recorded 24 h after surgery.ResultsAll 20 patients had reduced or lost cold sensation areas. The greatest extent of cold sensation reduction occurred at T7 (10%), and the least amount of cold sensation reduction occurred at L3 (10%). The block level covered T8 (20%), T9 (30%), T10 (45%), T11 (90%), T12 (95%), L1 (100%), and L2 (15%). Eighteen patients experienced areas of sensory loss, with the highest range at T11 and the lowest at L2. The duration of the blockade was 8.9 ± 3.8 h, with a maximum of 24 h and a minimum of 5 h. One patient experienced quadriceps weakness after surgery.ConclusionQuadratus lumborum block of intramuscular pathway can produce effective cutaneous sensory blockade, which can be used for postoperative analgesia of indirect inguinal hernia operation, and may also be beneficial to analgesia of other lower abdominal operations. However, the best method needs further confirmation to determine specific anesthesia methods for various operations.Chinese clinical trial registryJune 2, 2018; ChiCTR1800016457.

6812 A Rare Case of Polyglandular Autoimmune Syndrome Type 3B Presenting with Unsteady Gait Due to Subacute Combined Degeneration of the Spinal Cord Associated with Pernicious Anemia

Abstract Disclosure: F. Mohammadrezaei: None. F. Sajid: None. C.A. Resta: None. J.G. Karam: None. A Rare Case of Polyglandular Autoimmune Syndrome Type 3B Presenting with Unsteady Gait due to Subacute Combined Degeneration of the Spinal Cord associated with Pernicious Anemia Background: The coexistence of Hashimoto's thyroiditis and pernicious anemia is well established and is recognized as Polyglandular Autoimmune Syndrome (PAS) Type 3B [1]. We describe a rare case of a patient presenting with subacute combined degeneration of the spinal cord leading to the diagnosis of PAS Type 3B. Case Presentation: A 37-year-old man with no known medical history presented to the Emergency Department after a fall in the subway station. On history, he complained of progressive bilateral lower extremity weakness of 10 months duration, necessitating assistance with ambulation, and significant weight gain, described as an increase in his pants size from 40 to 56. His physical examination was relevant for weight of 145kg, BMI of 46.5, normal motor strength and sensation of the upper extremities, decreased strength at 4 out of 5 of bilateral hip flexion and extension, and decreased vibration sensation of bilateral lower extremities. He could not fully stand or walk due to imbalance and weakness. Blood testing revealed a hemoglobin level of 11.4 gm/dl (14-18), MCV of 108.8 FL (80-94), a significantly low vitamin B12 at 89 pg/ml, and normal folate level. His TSH level was 9.26 MCIU/ML (0.39-4.08), with a free T4 of 0.74 ng/dl (0.8-1.8) and significantly elevated Thyroid Peroxidase Antibody titer at 4320 IU/ml (< 34.9). Intrinsic factor antibody and parietal cell antibody tests both came back elevated at 13.4 AU/mL (0.0-1.1) and 1.8 (<1.2), respectively. A head CT scan showed no acute pathology, but MRI spine with contrast revealed abnormal T2 hyperintensity, primarily affecting the lateral columns throughout the cervical and thoracic cord, likely indicative of subacute combined degeneration. The patient was diagnosed with autoimmune Hashimoto's thyroiditis, pernicious anemia, and subacute combined degeneration of the spinal cord due to vitamin B12 deficiency. He was treated with daily vitamin B12 1000mcg muscular injections, levothyroxine 75mcg orally daily (after ruling out adrenal insufficiency), and physical therapy. Conclusion: This case highlights the complexity of polyglandular autoimmune syndromes and the importance of recognizing atypical presentations early in the history of disease. Comprehensive evaluation and timely intervention are essential to mitigate the progression of these conditions and improve patients' quality of life. Reference: (1) Betterle C, Furmaniak J, Sabbadin C, Scaroni C, Presotto F. Type 3 autoimmune polyglandular syndrome (APS-3) or type 3 multiple autoimmune syndrome (MAS-3): an expanding galaxy. J Endocrinol Invest. 2023 Apr;46(4):643-665. Presentation: 6/1/2024

The Many Roles of Precision in Action.

Active inference describes (Bayes-optimal) behaviour as being motivated by the minimisation of surprise of one's sensory observations, through the optimisation of a generative model (of the hidden causes of one's sensory data) in the brain. One of active inference's key appeals is its conceptualisation of precision as biasing neuronal communication and, thus, inference within generative models. The importance of precision in perceptual inference is evident-many studies have demonstrated the importance of ensuring precision estimates are correct for normal (healthy) sensation and perception. Here, we highlight the many roles precision plays in action, i.e., the key processes that rely on adequate estimates of precision, from decision making and action planning to the initiation and control of muscle movement itself. Thereby, we focus on the recent development of hierarchical, "mixed" models-generative models spanning multiple levels of discrete and continuous inference. These kinds of models open up new perspectives on the unified description of hierarchical computation, and its implementation, in action. Here, we highlight how these models reflect the many roles of precision in action-from planning to execution-and the associated pathologies if precision estimation goes wrong. We also discuss the potential biological implementation of the associated message passing, focusing on the role of neuromodulatory systems in mediating different kinds of precision.

Outcomes of Common Peroneal Nerve Decompression.

Common peroneal nerve (CPN) neuropathy is the most common lower extremity mononeuropathy. When delayed or no recovery from CPN neuropathy is suspected, surgical CPN decompression (CPND) is considered to relieve symptoms. This study aimed to evaluate patient outcomes post-CPND performed by a single surgeon at a tertiary medical center. Patient outcomes after CPND performed by a single surgeon were reviewed. Motor, sensation, and pain scores post-CPND were assessed in 47 of the 46 patients. Patient demographics, including age, concomitant morbidities, time from injury to surgery, and body mass index (BMI), were also analyzed for correlations with outcomes after CPND by logistic regression. 29/34 patients with impaired motor function improved by at least one motor grade, 19/42 with altered sensation reported restored normal sensation, and 31/37 reported improved pain after CPND. No correlation of patient demographic factors with motor or pain improvement after CPND was observed. However, a BMI greater than 29.15 and a time between injury and surgery exceeding 506 days were associated with lower odds of reporting restored sensation. Operative decompression of CPN neuropathy improves objective motor scores and subjective sensation and pain scores.

Contribution of kelp dashi liquid to sustainable maintenance of taste sensation and promotion of healthy eating in older adults throughout the umami-taste salivary reflex.

Taste decline, including taste loss in older adults, leads to malnutrition and frailty. In a super-aging society, improving taste decline and maintaining taste sensation are crucial for the wellbeing of older adults. Hyposalivation frequently affects older individuals and is the leading cause of taste decline in older adults. Treating taste decline, including taste loss, in older adults presents challenges due to the limited sustainable methods for increasing saliva production, except for drug therapy, which may lead to adverse effects. Umami-taste stimulation results in a prolonged increase in both the whole salivary flow rate (WF), more than 90% of which is secreted from the major salivary glands, and the minor salivary gland flow rate (MF) in healthy volunteers through the umami-taste salivary reflex. We hypothesized that umami-rich kelp dashi liquid (KDL), commonly used in Japanese cuisine, may alleviate taste decline and sustain normal taste sensation in older adults with hyposalivation. This study investigated whether KDL stimulation could improve taste decline. A non-randomized controlled trial was conducted at the dental department of a university hospital, involving those who presented with dry mouth between May 2017 and December 2021. Before and after repeated KDL stimulation, characteristics like changes in WF and MF, the recognition thresholds (RTs) for five basic tastes, and subjective eating and swallowing difficulties were assessed. Statistical comparisons were performed between the values measured before and after KDL stimulation. A total of 35 older patients were included. Patients with reduced MF and with or without reduced WF exhibited umami-taste loss. Repeated stimulation with KDL increased MF and WF and improved taste loss, including umami, decreased RTs, and normalized each taste. Furthermore, subjective taste impairment, subjective eating and swallowing difficulties, and burning sensations in the oral mucosa were alleviated. These findings indicate that KDL stimulation improved umami-taste loss and normalized each taste sensation, further alleviating eating difficulties via the umami-taste salivary reflex. Importantly, umami-taste loss was also observed in patients with normal WF but decreased MF, who are typically not diagnosed with hyposalivation. Therefore, KDL has the potential to sustain taste sensations and promote healthy eating habits in older individuals.

Application of topical 5-Fluorouracil to reduce the recurrence of odontogenic keratocyst: A prospective study with 2-year follow-up

ObjectivesThe purpose of this prospective study was to evaluate the effect of topical 5-Fluorouracil as an adjunct therapy in reducing the recurrence of odontogenic keratocyst. MethodsForty-eight patients with proven incisional biopsy as odontogenic keratocyst were included in this clinical study. The patients were divided into two equal groups, the test group patients were treated with 5-Fluorouracil cream after cyst enucleation. However, the control group patients were treated with cyst enucleation only. Recurrence (yes/no) was the primary outcome variable evaluated by clinical signs of inflammation, swelling, or pain within a 2-year follow-up. The pain was measured on a visual analogue scale, and swelling was measured pre-surgically using vertical and horizontal references, 1 week, 1 month, 3 months, 6 months, 12 months, and 24 months. Computed tomography was performed pre-surgically and 24 hours post-surgically, at 12-month, and 24-month intervals to evaluate local bone density. The T-test was used to compare between two studied groups. ResultsPost-surgical follow-up showed uneventful wound healing in both groups with no clinical signs of recurrence or swelling, pain results demonstrated that patients have decreased records throughout the observation periods with no significant difference between both groups. Normal sensation was encountered in all patients except for one patient in the control group who showed no sensation (score 2). Post-surgical radiographic findings revealed a considerable shift in bone density in all patients of both groups at the site of excised lesions during the follow-up periods compared with immediate post-surgical radiographs. However, the test group patients demonstrated a significant increase of bone density between different evaluation periods (P = 0.001) than the control group. ConclusionConservative enucleation of odontogenic keratocyst combined with topical application of 5-Fluorouracil is an effective treatment with lower recurrence rates, less morbidity, and normal bone healing.

Artificial dermal repair for larger finger pulp defects: Satisfactory coverage with limitations in sensation and inevitable scar formation

BackgroundThis prospective study aimed to evaluate the outcomes of the use of dermal templates for lengthy volar soft tissue defects (1.5–4 cm) in the fingers. MethodsThe volar soft tissue defects of 15 patients (19 fingers) were treated with Lando dermal template coverage between June 2022 and November 2022. We evaluated sensory recovery, scar formation, and overall appearance of the repair site at an average of 13 months (range, 12–17 months) of follow-up. ResultsThe defect healed in all cases. We found an average static 2-point discrimination of 7 mm (range 4 to 14 mm). Scar formation was evident in all cases. The repair did not restore the bulkiness of the volar finger, especially in the finger with the bony exposure. Nail deformities and joint contracture were observed in some cases. ConclusionDermal template repair does not restore normal sensation and inevitably leads to scar formation when the defect is longer (>1.5 cm). Bulkiness of the volar finger is not restored in most patients, especially when there was bone or tendon exposure in the initial wound site.

Piezo2 voltage-block regulates mechanical pain sensitivity.

PIEZO2 is a trimeric mechanically-gated ion channel expressed by most sensory neurons in the dorsal root ganglia. Mechanosensitive PIEZO2 channels are also genetically required for normal touch sensation in both mice and humans. We previously showed that PIEZO2 channels are also strongly modulated by membrane voltage. Specifically, it is only at very positive voltages that all channels are available for opening by mechanical force. Conversely, most PIEZO2 channels are blocked at normal negative resting membrane potentials. The physiological function of this unusual biophysical property of PIEZO2 channels, however, remained unknown. We characterized the biophysical properties of three PIEZO2 ion channel mutations at an evolutionarily conserved arginine (R2756). Using genome engineering in mice we generated Piezo2R2756H/R2756H and Piezo2R2756K/R2756K knock-in mice to characterize the physiological consequences of altering PIEZO2 voltage sensitivity in vivo. We measured endogenous mechanosensitive currents in sensory neurons isolated from the dorsal root ganglia and characterized mechanoreceptor and nociceptor function using electrophysiology. Mice were also assessed behaviourally and morphologically. Mutations at the conserved Arginine (R2756) dramatically changed the biophysical properties of the channel relieving voltage block and lowering mechanical thresholds for channel activation. Piezo2R2756H/R2756H and Piezo2R2756K/R2756K knock-in mice that were homozygous for gain-of-function mutations were viable and were tested for sensory changes. Surprisingly, mechanosensitive currents in nociceptors, neurons that detect noxious mechanical stimuli, were substantially sensitized in Piezo2 knock-in mice, but mechanosensitive currents in most mechanoreceptors that underlie touch sensation were only mildly affected by the same mutations. Single-unit electrophysiological recordings from sensory neurons innervating the glabrous skin revealed that rapidly-adapting mechanoreceptors that innervate Meissner's corpuscles exhibited slightly decreased mechanical thresholds in Piezo2 knock-in mice. Consistent with measurements of mechanically activated currents in isolated sensory neurons essentially all cutaneous nociceptors, both fast conducting Aδ-mechanonociceptors and unmyelinated C-fibre nociceptors were substantially more sensitive to mechanical stimuli and indeed acquired receptor properties similar to ultrasensitive touch receptors in Piezo2 knock-in mice. Mechanical stimuli also induced enhanced ongoing activity in cutaneous nociceptors in Piezo2 knock-in mice and hyper-sensitive PIEZO2 channels were sufficient alone to drive ongoing activity, even in isolated nociceptive neurons. Consistently, Piezo2 knock-in mice showed substantial behavioural hypersensitivity to noxious mechanical stimuli. Our data indicate that ongoing activity and sensitization of nociceptors, phenomena commonly found in human chronic pain syndromes, can be driven by relieving the voltage-block of PIEZO2 ion channels. Indeed, membrane depolarization caused by multiple noxious stimuli may sensitize nociceptors by relieving voltage-block of PIEZO2 channels.

Assessment of photobiomodulation by a 660-nm diode laser on the reversal of soft tissue anesthesia in children: A randomized controlled clinical trial.

Soft tissue anesthesia (STA) following inferior alveolar nerve block (IANB) anesthesia lasts 3-5 h. It is important to reverse STA after treatment to prevent soft tissue injury (STI). This study evaluated photobiomodulation using a 660 nm diode laser on STA reversal and its impact on STI following IANB anesthesia. A randomized controlled clinical trial was conducted on 32 children, aged 5-8 years, allocated into the test and control groups. Anesthesia was administered; the operative procedure was performed followed by exposure to laser. STA reversal was monitored through lip tapping, current perception threshold (CPT) tests, and paediatric Functional Assessment Battery. The test group showed significantly faster recovery to normal sensation following exposure to laser than the control group which did not undergo any reversal (p < .0001), with a median time of 115 and 60 min according to lip tapping and CPT tests, respectively. The test group also showed significantly faster recovery to normal function (p = .016). The incidence of STI in the form of redness was significantly higher in the control group (p = .022). Photobiomodulation using a 660 nm diode laser can be considered as an efficient approach to minimize STA and STI after dental interventions.

GABA transporter mGat4 is involved in multiple neural functions in mice

γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system. The termination of GABA transmission is through the action of GABA transporters (GATs). mGAT4 (encoded by Slc6a11) is another GAT besides GAT1 (encoded by Slc6a1) that functions in GABA reuptake in CNS. Research on the function of mGAT4 is still in its infancy. We developed an mGat4 knockout mouse model (mGat4−/− mice) and performed a series of behavioral analyses for the first time to study the effect of mGat4 on biological processes in CNS. Our results indicated that homozygous mGat4−/− mice had less depression, anxiety-like behavior and more social activities than their wild-type littermate controls. However, they had weight loss and showed motor incoordination and imbalance. Meanwhile, mGat4−/− mice showed increased pain threshold and hypoalgesia behavior in nociceptive stimulus and learning and memory impairments. The expression of multiple components of the GABAergic system including GAD67, GABAA and KCC2 was altered. There is little or no compensatory change in mGat1. In a word, mGat4 may play a key role in normal motor coordination, sensation, emotion, learning and memory and could be the potential target of neurological disorders.

Aberrant occlusal sensitivity in adults with increased somatosensory amplification: a case-control study.

Occlusal sensitivity (OS)-the ability to detect fine objects between opposing teeth-mainly relies on the activity of mechanoreceptors located in the periodontal ligament. We tested whether somatosensory amplification (SSA)-the tendency to perceive normal somatic sensations as being intense, noxious, and disturbing, which plays a critical role in hypervigilance-affects OS. We measured OS in 66 adults divided into three groups based on their SSA scores (LowSSA, Intermediate - IntSSA, HighSSA) by asking them to bite on aluminum foils (8 to 72μm thick) and a sham foil, and report whether they felt each foil. We performed 20 trials for each thickness and sham condition (each participant was tested 120 times), and compared the frequency of correct answers (%correct) among groups after adjusting for participants' trait anxiety, depression, self-reported oral behaviors, and masseter cross-sectional area. %correct was affected by the interaction Foil Thickness-by-SSA (p = 0.007). When tested with the 8μm foil, the HighSSA group had a lower %correct than the IntSSA (contrast estimate [95% CI]: -14.2 [-25.8 - -2.6]; p = 0.012) and the LowSSA groups (-19.1 [-31.5 - -6.6]; p = 0.001). Similarly, with the 24μm foil, the HighSSA group had a lower %correct compared to the IntSSA (-12.4 [-24.8-0.1]; p = 0.048) and the LowSSA groups (-10.8 [-22.5-0.8]; p = 0.073). Individuals with high SSA present with an aberrant occlusal sensitivity. Our findings provide novel insights into the relationship between occlusal perception and psychological factors, which may influence an individual's ability to adapt to dental work.

Midfacial toddler excoriation syndrome (MiTES): case series, diagnostic criteria and evidence for a pathogenic mechanism.

PRDM12 polyalanine tract expansions cause two different disorders: midfacial toddler excoriation syndrome (MiTES; itch with normal pain sensation associated with 18 homozygous alanines (18A); and congenital insensitivity to pain (CIP) with normal itch associated with 19 homozygous alanines (19A). Knowledge of the phenotype, genotype and disease mechanism of MiTES is incomplete. Why 18A vs. 19A PRDM12 can cause almost opposite phenotypes is unknown; no other polyalanine or polyglutamine tract expansion disease causes two such disparate phenotypes. To assess the genotype and phenotype of nine new, nine atypical and six previously reported patients diagnosed with MiTES. Using cell lines with homozygous PR domain zinc finger protein 12 (PRDM12) containing 12 alanines (12A; normal), 18A (MiTES) and 19A (CIP), we examined PRDM12 aggregation and subcellular localization by image-separation confocal microscopy and subcellular fractionation Western blotting. MiTES presents in the first year of life; in all cases the condition regresses over the first decade, leaving scarring. The MiTES phenotype is highly distinctive. Features overlapping with PRDM12 CIP are rarely found. The genotype-phenotype study of the PRDM12 polyalanine tract shows that having 7-15 alanines is normal; 16-18 alanines is associated with MiTES; 19 alanines leads to CIP; and no clinically atypical cases of MiTES had a polyalanine tract expansion. PRDM12 aggregation and subcellular localization differed significantly between 18A and normal 12A cell lines and between 18A and 19A cell lines. MiTES is a new protein-aggregation disease. We provide diagnostic criteria for MiTES and improved longitudinal data. MiTES and CIP are distinct phenotypes, despite their genotypes varying by a single alanine in the PRDM12 polyalanine tract. We found clear distinctions between the cellular phenotypes of normal, MiTES and CIP cells. We hypothesize that the developmental environment of the trigeminal ganglion is unique and critically sensitive to pre- and postnatal levels of PRDM12.

Effects of melatonin on postoperative pain and sensory recovery following zygomaticomaxillary complex fractures — A randomized controlled trial

Posttraumatic and postsurgical sensory disturbance is a known complication of almost all zygomaticomaxillary (ZMC) complex fractures involving the infraorbital nerve, for which few treatments are effective. Our study used neurosensory assessments to evaluate the efficacy of melatonin on pain and nerve healing following ZMC surgery.Sixty-four randomly allocated ZMC fracture patients were prophylactically administered either oral melatonin or an identical placebo for 15 consecutive days. Pre- and postsurgical clinical parameters included subjective pain, numbness, and objective neurosensory function.Melatonin significantly reduced subjective pain perception in the early postoperative days, with a significant difference in VAS scores between the groups from postoperative day 3 (p = 0.048) until day 7 (p = 0.002). The VAS assessment of subjective numbness perception showed significantly lower self-perceived neurosensory disturbance for patients in the interventional group from the first month (p = 0.039) until the third month (p = 0.005). Objective neurosensory assessment using the pinprick test and two-point discrimination showed statistically significant improvement to almost normal sensation by the first month (p = 0.014) to fully normal sensation by the third month (p = 0.001).The study findings suggest that the prophylactic administration of melatonin confers significant clinical benefits in terms of reduced postoperative pain and improved sensory recovery.

Enhanced Recovery of Local Anesthesia in Pediatric Patients: The Impact of Photobiomodulation on Reversing Anesthesia Effects.

BACKGROUND The split-mouth study design is used in oral health research and usually consists of 2 treatments randomly assigned to either the right or left side. This split-mouth study aimed to evaluate the efficacy of photobiomodulation on reversal of local anesthesia in 50 children aged 8-10 years. MATERIAL AND METHODS The study was conducted among 50 children: 27 girls and 23 boys, aged 8-10 years (mean age 9.38±1.15 years), who presented 2 carious maxillary permanent molars. One side was randomly assigned to the laser group (50 teeth), and the contralateral side to the control group (50 teeth). At the end of the treatment, photobiomodulation (PBM) was performed in the area of infiltration at 6 points, with 635 nm (25 children) (250 mW, 500 mW/cm², 15J) and 808 nm (25 children) (200 mW, 400 mW/cm², 12J) (SmartM PRO, Lasotronix, Poland). On the contralateral side, the laser's off-mode applicator was used. Anesthetic effect was evaluated by palpation test (soft tissues) and electrical test (dental pulp). RESULTS After 15 minutes, in the laser group the return to normal sensations in the palpation test showed 88% (808 nm) and 68% (635 nm), and only 20% in the control group (P=0.04123). After 45 minutes, all the participants from the PBM group returned to normal sensations (P=0.21458). Dental pulp's excitability threshold was lower for both wavelengths compared to the control group (P=0.000001). CONCLUSIONS The identification of factors accelerating the recovery time to normal function, such as PBM, can be used as important data to eliminate self-injury secondary to local anesthesia (LA) in children.

A70 INABILITY TO AMBULATE FOLLOWING COLONOSCOPY: AN UNEXPECTED COMPLICATION

Abstract Background The peroneal nerve innervates the lower extremities. Compression injury has been documented in the adult patients following the lithotomy position perioperatively, but has rarely been described in pediatric patients following colonoscopy. Aims To report a rare complication following colonoscopy and discuss possible aetiologies. Methods A chart review of a post-colonoscopy peroneal nerve injury in a pediatric patient was conducted along with a literature review. Results A 12 year old boy with ulcerative colitis underwent a colonoscopy for flare symptoms. He was in the left lateral decubitus position for 60 minutes. Immediately after the procedure, he experienced loss of sensation from the left knee to the plantar aspect of the foot, and left foot drop. He had no symptoms of weakness or paresthesia in the right lower extremity or the upper extremities. Prior to the procedure, he reported normal strength, function, and sensation of all extremities. He had no history of injury, joint inflammation or previous surgery affecting his left leg. He had no recent history of steroid use or systemic illness. Two months post procedure he had some symptom improvement and could independently ambulate. He had normal range of motion, strength, and sensation in the upper extremities and right lower extremity. His left leg had 4/5 strength on dorsiflexion and decreased pinprick and light touch sensation. He had difficulty with heel-toe walking. Reflexes were normal. Left leg X-ray and spine MRI were normal. Electrodiagnostic evaluation supported a left common peroneal nerve injury, predominantly demyelinating in nature with minimal axonal contribution, likely secondary to compression around the fibular head during the time of the colonoscopy. He showed full recovery and returned to baseline by 7 months. Conclusions Peroneal nerve injury post colonoscopy is very rare. A study focusing on pediatric colonoscopy found that 3 of 746 patients experienced postoperative neuropathies in their lower extremities. Procedure times were between 70-120 minutes. Presentations and recovery periods were variable, lasting several days to 3 months. The mechanisms of this injury are unclear and felt unlikely to be secondary to positioning alone. It is speculated that BMI, procedure length, frog leg position and position changes, as well as systemic inflammation may be contributory. Factors such as hypothermia, dehydration, hypotension, hypoxia, and electrolyte disturbances may further place patients at risk. Awareness of this rare event and potential modifiable risk factors is important. Funding Agencies None

P499 Anorectal Motility Disorders In Inflammatory Bowel Disease Patients

Abstract Background In spite of prolonged disease remission of IBD patients, induced by the new biological molecules, a significant number of them suffer from persistent debilitating symptoms with major impact on the quality of life. Frequently, these symptoms are due to post-inflammatory motility changes and misinterpreted as functional disorders. Our aim is to identify and characterize the anorectal motility dysfunction in IBD patients. Methods We are conducting an ongoing prospective study started in August 2019, which includes the IBD patients admitted in a Tertiary Gastroenterology Centre in Bucharest, with specific symptoms (anorectal pain, incontinence, difficult defecation). We perform high resolution anorectal manometry using Sandhill Scientific systems, the parameters being analysed using InSIGHT software. The manometric testing comprise measurements of anorectal pressure at rest, during squeeze, simulated evacuation, rectoanal inhibitory reflex (RAIR) and rectal sensory testing, in compliance with International Anorectal Physiology Working Group protocol Results We studied 30 patients (18 patients with Ulcerative Colitis and 12 patients with Crohn’s Disease, 18 females and 12 males, mean age 40 (±12.85) years. Only 33% (10 patients) had rectal active involvement. Symptoms were reported by 87% (26) patients: anal incontinence (85%), difficult evacuation (35%) and urgency (46%); rectal inflammation was not correlated with the presence of symptoms in our study group (p=0.28). Perianal surgical interventions didn’t represent a risk factor for fecal incontinence (p=0.18), or for dyssinergic defecation (p=0.1). Modified manometric parameters were found in 23 patients (79%). Low resting pressures were registered in 48% of patients; 55% of them presented low squeeze pressures; during push maneuvers, 34% of patients had insufficient rectal propulsive force, presenting low rectal pressures and 59% of them lacked anal canal relaxation. We performed sensibility testing on 18 patients: 9 patients presented criteria for hypersensitivity, hence reduced rectal compliance; 7 patients presented rectal hyposensitivity, while only 2 patients had normal rectal sensation. Recto-anal inhibitory reflex (RAIR) was present only in 28% of the patients, reflecting the dysfunction of the enteric neural system. Conclusion Patients with inflammatory bowel disease (IBD) have significantly higher rates of functional anorectal disease. Therefore, pelvic floor investigation is an essential tool in the investigation and management of IBD patients with ongoing symptoms not thought to be related to an IBD flare.

Role of sodium leak channel (NALCN) in sensation and pain: an overview.

The sodium leak channel (NALCN) is widely expressed in the central nervous system and plays a pivotal role in regulating the resting membrane potential (RMP) by mediating the Na+ leak current. NALCN was first reported in 1999, and since then, increasing evidence has provided insights into the structure and functions of NALCN. As an essential component of neuronal background currents, NALCN has been shown to be involved in many important physiological functions, particularly in the respiratory rhythm, as NALCN mutant mice have a severely disrupted respiratory rhythm and die within 24h of birth. Many patients with NALCN mutations also develop serious clinical syndromes, such as severe hypotonia, speech impairment, and cognitive delay. Recently, emerging studies have clarified the human NALCN structure and revealed additional properties and functions of NALCN. For instance, accumulating evidence highlights that the NALCN is involved in normal sensation and pain. Here, we review the current literature and summarize the role of the NALCN in sensation and pain.

Spinal cord injury-induced neurogenic bowel: A role for host-microbiome interactions in bowel pain and dysfunction

Background and aimsSpinal cord injury (SCI) affects roughly 300,000 Americans with 17,000 new cases added annually. In addition to paralysis, 60% of people with SCI develop neurogenic bowel (NB), a syndrome characterized by slow colonic transit, constipation, and chronic abdominal pain. The knowledge gap surrounding NB mechanisms after SCI means that interventions are primarily symptom-focused and largely ineffective. The goal of the present studies was to identify mechanism(s) that initiate and maintain NB after SCI as a critical first step in the development of evidence-based, novel therapeutic treatment options. MethodsFollowing spinal contusion injury at T9, we observed alterations in bowel structure and function reflecting key clinical features of NB. We then leveraged tissue-specific whole transcriptome analyses (RNAseq) and fecal 16S rRNA amplicon sequencing in combination with histological, molecular, and functional (Ca2+ imaging) approaches to identify potential mechanism(s) underlying the generation of the NB phenotype. ResultsIn agreement with prior reports focused on SCI-induced changes in the skin, we observed a rapid and persistent increase in expression of calcitonin gene-related peptide (CGRP) expression in the colon. This is suggestive of a neurogenic inflammation-like process engaged by antidromic activity of below-level primary afferents following SCI. CGRP has been shown to disrupt colon homeostasis and negatively affect peristalsis and colon function. As predicted, contusion SCI resulted in increased colonic transit time, expansion of lymphatic nodules, colonic structural and genomic damage, and disruption of the inner, sterile intestinal mucus layer corresponding to increased CGRP expression in the colon. Gut microbiome colonization significantly shifted over 28 days leading to the increase in Anaeroplasma, a pathogenic, gram-negative microbe. Moreover, colon specific vagal afferents and enteric neurons were hyperresponsive after SCI to different agonists including fecal supernatants. ConclusionsOur data suggest that SCI results in overexpression of colonic CGRP which could alter colon structure and function. Neurogenic inflammatory-like processes and gut microbiome dysbiosis can also sensitize vagal afferents, providing a mechanism for visceral pain despite the loss of normal sensation post-SCI. These data may shed light on novel therapeutic interventions targeting this process to prevent NB development in patients.

Advantages of a High-Powered Ultrasonic Vibration Cutting Device for Orthognathic Surgeries.

This study aimed to evaluate the advantages of using a high-powered ultrasonic vibration cutting device (HP-UVCD) in orthognathic surgeries. We analyzed 22 consecutive patients who underwent Le FortⅠosteotomy and bilateral sagittal split osteotomies for cleft lip and palate. We used conventional power instruments, such as reciprocating saws and rotating burrs in the first 10 patients, and an HP-UVCD in the remaining 12 patients. Surgical time, intraoperative blood loss, and postoperative inferior alveolar nerve affection were retrospectively investigated. The surgical time in the ultrasonic group (223±12.217min) was significantly shorter than that in the conventional group (278±11.153min, P =0.008). The amount of intraoperative blood loss in the ultrasonic group was an average of 230±45.154g, and that in the conventional group was an average of 343±49.463g. Although the blood loss in the ultrasonic group was reduced compared with that in the conventional group, this difference was not statistically significant ( P =0.118). All patients in both groups recovered normal sensation by 6 months postoperatively. Our findings suggest that the HP-UVCD can be used in place of a reciprocating saw or rotating burrs in orthognathic surgeries, resulting in reduced surgical time and minimal blood loss. The use of an ultrasonic bone-cutting device may allow for a safer and less invasive orthognathic surgery.

First do no harm: A patient-reported survey of split skin graft donor site morbidities following thin and super-thin graft harvest

The split-thickness skin graft (STSG) donor site is the commonest used during burn surgery which has its own complications and as such the focus should be on minimizing it. Modifications to practice in our unit which we believe aid this include limiting the amount of STSG taken and the harvest of super-thin STSGs, with 0.003–0.005 in. (0.08–0.13 mm) being the commonest dermatome settings used. A patient-reported survey via a mobile phone link to a questionnaire was sent to 250 patients who had a STSG for an acute burn between 1st August 2020 and 31st July 2021. Patient demographics were collected from electronic records including the thickness of the FTSG taken when recorded. Patient responses were statistically analyzed and logistic regression with backwards elimination was performed to explore which contributing factors led to an improved experience of the donor site. Questionnaire responses were obtained from 107 patients (43%). These were between one and two and a half years after the injury. Concerning early donor site issues, itch was a problem for 52% of patients, pain was a problem for 48% of patients. Less common problems (fewer than 25% of patients) were leaking donor sites, wound breakdown, and over-granulation. Regarding long-term outcomes, increased, decreased or mixed pigmentation at the donor site was reported by 32% patients at the time of the survey. Hyper-vascular donor sites were reported by 24% patients. Raised or uneven feeling donor sites were reported by 19% patients, firm or stiff donor sites by 13% patients, and altered sensation by 10% patients. At the time of the survey, 70% responders reported their donor site looked “the same or about the same as my normal skin”. Of these, 62 reported how long it took for this to happen, and it equates to a third looking normal at 6 months and half looking normal at a year. For the 32 patients who reported their donor site looking abnormal, 72% were “not bothered” by it. Patients with super-thin grafts (0.003–0.005 in.) were significantly more likely to have normal sensation, normal stiffness, and be less raised at their donor sites than those who had thin grafts (0.006–0.008 in.). This survey gives important information on patients’ experiences of donor site morbidity that may form part of an informed consent process and allow tailored advice. Furthermore, it suggests that super-thin grafts may provide a superior donor site experience for patients.