Primary Nerve Research Articles

Gamma distribution model of diffusion MRI for the differentiation of primary central nerve system lymphomas and glioblastomas.

The preoperative imaging-based differentiation of primary central nervous system lymphomas (PCNSLs) and glioblastomas (GBs) is of high importance since the therapeutic strategies differ substantially between these tumors. In this study, we investigate whether the gamma distribution (GD) model is useful in this differentiation of PNCSLs and GBs. Twenty-seven patients with PCNSLs and 57 patients with GBs were imaged with diffusion-weighted imaging using 13 b-values ranging from 0 to 1000 sec/mm2. The shape parameter (κ) and scale parameter (θ) were obtained with the GD model. Fractions of three different areas under the probability density function curve (f1, f2, f3) were defined as follows: f1, diffusion coefficient (D) <1.0×10-3 mm2/sec; f2, D >1.0×10-3 and <3.0×10-3 mm2/sec; f3, D >3.0 × 10-3 mm2/sec. The GD model-derived parameters were compared between PCNSLs and GBs. Receiver operating characteristic (ROC) curve analyses were performed to assess diagnostic performance. The correlations with intravoxel incoherent motion (IVIM)-derived parameters were evaluated. The PCNSL group's κ (2.26 ± 1.00) was significantly smaller than the GB group's (3.62 ± 2.01, p = 0.0004). The PCNSL group's f1 (0.542 ± 0.107) was significantly larger than the GB group's (0.348 ± 0.132, p<0.0001). The PCNSL group's f2 (0.372 ± 0.098) was significantly smaller than the GB group's (0.508 ± 0.127, p<0.0001). The PCNSL group's f3 (0.086 ± 0.043) was significantly smaller than the GB group's (0.144 ± 0.062, p<0.0001). The combination of κ, f1, and f3 showed excellent diagnostic performance (area under the curve, 0.909). The f1 had an almost perfect inverse correlation with D. The f2 and f3 had very strong positive correlations with D and f, respectively. The GD model is useful for the differentiation of GBs and PCNSLs.

Multiple Primary Cardiac Malignant Peripheral Nerve Sheath Tumors in the Left Atrium

Malignant peripheral nerve sheath tumors are rare sarcomas of the heart. Herein, we report the case of a 24-year-old man who complained of dyspnea, cough, and upper left back pain. He was found to have multiple primary heart tumors obstructing the right superior pulmonary vein in the left atrium, which were diagnosed as malignant peripheral nerve sheath tumors. The patient underwent successful resection of the tumors and immunohistochemistry was utilized for diagnosis.

Decompression and Neurolysis of the Lateral Femoral Cutaneous Nerve in the Surgical Treatment of Meralgia Paresthetica and the Results

AbstractMeralgia paresthetica (MP), also known as Bernhardt–Roth syndrome, is a peripheral neuropathy of the primary sensory lateral femoral cutaneous nerve (LFCN). Its diagnosis is challenging, because it can mimic other clinical conditions particularly associated with upper lumbar spine or pelvis. Patients present with pain and paresthesia over the anterolateral thigh. Diagnosis is usually based on clinical examination and is supported by sensory nerve conduction (SNC) studies. The initial treatment is always conservative. In limited number of patients who are refractory to conservative managements, surgical treatment via decompression/neurolysis or neurectomy is concerned. There is still no consensus on which surgical technique is the best and the first choice. We retrospectively analyzed the surgical outcomes of 12 nonobese patients who underwent decompression/neurolysis between the years 2013 and 2018. Bilateral SNC studies were performed in all cases which supported the diagnosis. We applied conservative treatments for 3 months in addition to the treatments previously applied in other centers. Surgery was recommended for the patients who were refractory to these treatments. Preoperative and postoperative pain levels during follow-up visits were evaluated with visual analogue scale (VAS). A retrospective analysis was performed on preoperative and postoperative 6th month VAS scores. The mean preoperative VAS value was 8.75 ± 0.62 and the postoperative VAS value at the sixth month was 1.17 ± 0.72. A significant reduction in the pain was shown (p &lt; 0.05). Our surgical results showed that decompression/neurolysis of the LFCN should be concerned as the primary surgical approach to avoid negative outcomes of resection surgeries.

Topical Capsaicin for the Treatment of Neuropathic Pain.

Neuropathic pain (NP) is an egregious problem worldwide. Due to the side-effects of oral drugs, drugs delivered directly to the affected area of pain are preferred. Capsaicin, a chemical compound isolated from chili peppers, is used as an analgesic in topical ointments and dermal patches to alleviate pain. Objective of the study is to review the application and functionality of topical capsaicin in treatment of neuropathic pain. To systematically review capsaicin's functions on NP, we retrieved articles from the PubMed database published in the last ten years. The inclusion criteria were capsaicin and the use of capsaicin for the treatment of NP; on the other hand, articles were excluded according to the mentioned criteria such as abstracts, articles written in any language other than English, incomplete articles, and conference papers. Out of 265 articles, 108 articles were selected after filtering through the inclusion and exclusion criteria. The data and knowledge currently existing for capsaicin treatment in NP are summarized. This review indicates that capsaicin effectively improves NP treatment without affecting the motor and large nerve fibres involved in sensory function. Transient receptor potential channel vanilloid type 1 (TRPV1) is the capsaicin receptor expressed in central and peripheral terminals of a sensitive primary nerve cell. Conclusions and implications of key findings: Topical capsaicin has a sensible safety profile and is effective in reducing NP. Therefore, studies over the last decade suggest that capsaicin might be a potential drug for NP treatment.

Incidence and Management of Radial Nerve Palsies in Humeral Shaft Fractures: A Systematic Review.

Radial nerve palsies in closed humeral shaft fractures are common, with an incidence of 7%-17%. The management of radial nerve palsies in closed fractures is often expectant, with 70.7% spontaneously recovering within six months. A literature search was conducted for studies on radial nerve palsies in humeral shaft fractures from 2000-2018. A total of 4972 humeral shaft fractures were identified, with an incidence of 12.2% of primary radial nerve palsies. During the exploration, no neurological intervention was performed in nearly 41% of cases, and the most common finding was no evidence of any nerve lesion (35%). Those who underwent neurolysis were more likely to resolve when compared to primary repair or nerve grafting. Overall, there was a high rate of spontaneous radial nerve palsy recovery (85%) with radial nerve exploration increasing rates of resolution. While exploration demonstrates increased resolution, it is yet to be determined which fractures are indicated for nerve exploration.

Primary Central Nerve System Lymphoma Affecting the Lumbosacral Nerve Root: A Case Report

Primary Central Nerve System Lymphoma Affecting the Lumbosacral Nerve Root: A Case Report

Minimally invasive percutaneous plate osteosynthesis for treatment of proximal humeral shaft fractures.

The objective of this study was to evaluate the feasibility and safety of a minimally invasive percutaneous plate osteosynthesis (MIPPO) procedure for proximal humeral shaft fractures using lateral minimal proximal and distal approaches and lateral bridge plating with primary radial nerve control, and to assess its clinical and radiographic outcomes. A retrospective review was done for the medical records of adult patients admitted for fracture of the proximal humeral shaft without associated injury to the ipsilateral upper limb and who consented to undergo a novel MIPPO technique herein reported. Patients were reviewed at regular follow-up periods and assessed at a final follow-up for evaluation of Constant, normalized Constant, and QuickDASH scores. There were 21 adult patients with mean age of 56years. Three patients were lost from early follow-up; one of them had post-operative radial nerve paralysis. Eighteen patients were reviewed for the purpose of this study at a mean of 20months of final follow-up; among them, one patient developed post-operative radial nerve paralysis with complete recovery after three months. Bone healing was achieved without any malalignment in 17 patients at a mean of 15weeks, and one patient developed nonunion. At final assessment (mean, 20months), the mean values of Constant, normalized Constant, and QuickDASH scores were 84 (range, 59 to 100), 95 (range, 73 to 100), and 5 (range, 0 to 18.2) respectively. Compared to pre-reported methods of MIPPO, this technique of lateral proximal and distal mini-approaches with lateral bridge plating after primary control of the radial nerve seems safe and feasible for proximal humeral shaft fractures. It gives good clinical and radiographic results with excellent restoration of upper limb function, very low incidence of post-operative radial nerve injury, and high rate of bone union in good alignment.

The Contribution of Intensity-Modulated Radiotherapy after Non-curative Intent Surgery for Head and Neck Adenoid Cystic Carcinoma

Incomplete surgery (gross total resection, near total resection, and subtotal resection) of head and neck adenoid cystic carcinoma (HNACC) is controversially considered as an unfavorable prognostic factor as to curative intent surgery (CIS). However, in Intensity-Modulated Radiotherapy (RT) era, after planed incomplete surgery (PIS), intensified RT or RT with concurrent chemotherapy (CCT) may contribute to tumor control and survival. Thus, we investigated the contribution of IMRT after PIS on local control and survival in HNACC. Retrospective review was performed for 170 consecutive patients with HNACC treated with curative postoperative IMRT with or without concurrent chemotherapy, between 2015 and 2018, after PIS (n = 102) or CIS (n = 68). All plan target volumes were designed to including the primary tumor and related cranial nerve pathway. Patients with other malignant tumors or distant metastasis were excluded. Among the 170 patients (98 women and 72 men; median age, 53 years), the median follow-up time was 27.8 (range, 9.6-59.1) months. The estimated 3-year local-regional recurrence-free survival (LRRFS) rate, progression-free survival (PFS) rate, overall survival (OS) rate, and distant metastasis-free survival (DMFS) rate were 92.4% (95%CI: 87.3-95.9), 74.7% (95%CI: 67.5-81.0), 98.5% (95%CI: 94.9-99.6), and 76.0% (95%CI: 68.7-82.1), respectively. Patients with high grade, Ki-67≥10%, Stage III-IV, extra-nodal extension (ENE), perineural invasion (PNI) and positive margin was associated with worse PFS (p<0.0001, p = 0.002, p = 0.003, and p = 0.0004, p = 0.042, and p = 0.021, respectively). The baseline and treatment characteristics were equally distributed between PIS and CIS group, except that there were more patients with positive margin and received RT dose≥66 Gy in PIS group (p = 0.000 and p = 0.000). There was no difference in LRRFS, DFS, OS, and DMFS between two groups, both in stage I-II and Stage III-IV (p = 0.280, p = 0.371, p = 0.752, and p = 0.549, respectively). Among patients with high grade, Ki-67≥10%, ENE or PNI, there was also no difference in PFS between two groups. Among patients received radiation dose<66Gy, PIS group patients had significant worse PFS (p = 0.029), while among patients without any CCT, PIS group patients had marginal significant worse PFS (p = 0.067). In IMRT era, PIS does not compromise oncologic treatment, even in patients with worse prognostic factors; however, Doses of ≥66 Gy or CCT might be essential. This strategy warrants further evaluation in prospective randomized trials with longer follow-up.

Radiographic and Clinical Outcomes of the Shoulder in Long-Term Follow-Up of Brachial Plexus Birth Injury

The purpose of this study was to examine radiographic and functional outcomes of the shoulder in brachial plexus birth injury (BPBI) patients at long-term follow-up. Medical records were reviewed at the Shriners Hospital in St. Louis to identify patients older than 18 years with a diagnosis of BPBI. Twenty-five patients were included in this study. Evaluations included radiographic examination, clinical examination, and outcome measures including the Mallet classification, visual analog scale (VAS) for shoulder pain, American Shoulder and Elbow Shoulder score (ASES), quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH), Simple Shoulder Test (SST), and Patient-Reported Outcomes Measurement Information System (PROMIS) domain measures. The mean age of the patients included was 44 years. Average follow-up was 37 years. No patient had primary nerve reconstruction surgery. Thirteen patients had a history of shoulder surgery at an average age of 6 years. There was a wide spectrum of deformity seen radiographically. Fifty-five percent of patients had evidence of glenoid retroversion, posterior humeraltranslation, or a biconcave glenoid. An additional 20% of patients had complete posterior dislocation of the humeral head. Despite the degenerative changes seen on radiographs, the mean VAS for pain was low, at 2. The mean ASES shoulder score was 54. The mean QuickDASH score was 30. Mean PROMIS Physical Function, Pain Interference, Depression, and Anxiety scores were near the means for the general population, with similar outcomes inpatients treated with shoulder surgery compared with those treated without surgery. Adult BPBI patients experience minimal shoulder pain despite deformity and degenerative changes on shoulder radiographs. Whereas there are significant deficits in range of motion and function, PROMIS scores in adult BPBI patients are normal. Therapeutic IV.

Anterior Subcutaneous Transposition With Expanded Polytetrafluoroethylene (ASTEP) for Cubital Tunnel Syndrome: Technical Note.

Ulnar nerve entrapment neuropathy at the elbow is the most common upper-extremity entrapment neuropathy after carpal tunnel syndrome. Surgical treatment can be complicated by perineural scarring and fibrosis, which may lead to recurrent symptoms. Expanded polytetrafluoroethylene (ePTFE) is a synthetic polymer with antiadhesive properties. To introduce the operative technique and outcomes of anterior subcutaneous transposition with ePTFE (ASTEP) in primary and recurrent cubital tunnel neuropathy. We studied 14 adult patients (11 men, 3 women; mean age, 45 yr) with cubital tunnel neuropathy (10 primary, 4 revision) who underwent surgery with the ASTEP technique between January 2008 and May 2018. Pain, numbness in the fourth/fifth fingers, and weakness of the intrinsic hand muscles were the most common presenting symptoms. Surgical outcomes were assessed using the modified McGowan and Wilson-Krout criteria. The average (± standard deviation) preoperative symptom duration was 12.1±5.2 mo (McGowan Grade 1, n=5; Grade 2, n=6; Grade 3, n=3). No intraoperative or postoperative complications were observed with the ASTEP technique. Postoperative follow-up ranged from 9 mo to 7 yr (mean, 4.3 yr). All 14 patients experienced improvement in or complete resolution of their symptoms after this unique intervention. Our novel technique of anterior transposition of the ulnar nerve with ePTFE was safe and highly effective in treating primary and recurrent ulnar nerve entrapment neuropathy at the elbow and represents an alternative to the current techniques.

The extracellular matrix composition of the optic nerve subarachnoid space

The meninges not only surround the brain and the spinal cord but also the optic nerve. Meningeal-derived extracellular matrix (ECM) is a crucial component of the pial basement membrane, glia limitans and important for maintenance of optic nerve axon integrity, homeostasis and retinal ganglion cell health. To get closer insight into optic nerve meningeal-derived ECM composition, we performed proteomic analysis of the sheep optic nerve subarachnoid space (SAS). Candidate components were confirmed in cultures of primary human meningothelial cells (phMECs) and human optic nerve samples. Sheep optic nerve SAS samples were analysed by LC-MS, identified proteins were matched to their human orthologs and filtered using gene lists representing all major ECM components. To validate these findings digital droplet PCR (ddPCR) to evaluate mRNA expression of all candidate components identified was performed on cultures of phMECs. In addition, one protein per major ECM group was stained on human optic nerve sections and on phMEC cultures. Employing LC-MS, 1273 proteins were identified and subjected to bioinformatic analysis. Gene ontology analysis revealed six out of forty-four collagen types (1A1, 1A2, 3A1, 6A2, 6A3 and 14A1), three out of eleven laminin subunits (A4, B2, C1) and six out of twenty-seven hyaluronan binding proteins (CD44, versican (VCAN), C1q binding protein, neurocan (NCAN), brevican (BCAN) and hyalaluronan proteoglycan link protein 2 (HAPLN2)) were present in our cohort. DdPCR in phMEC cell culture confirmed presence of all candidate components except NCAN, BCAN and HAPLN2. Immunohistochemistry (IHC) staining on human optic nerve sections and immunofluorescence (IF) staining on in vitro cultured phMECs showed strong immunopositivity for collagen-typeI-α1 (COL1A1), lamininγ1 (LAMC1), and VCAN. Fibronectin (FN1) was exclusively present in cultures of phMECs. Using a combined bioinformatics and immunohistological approach, we describe the ECM composition of the optic nerve subarachnoid space. As this space plays an important role in maintaining optic nerve function, a better understanding of ECM composition in this delicate environment might be key to further pathophysiological insight into optic nerve degeneration and associated disorders.

Primary malignant peripheral nerve sheath tumour of the trachea: a case report and literature review

BackgroundMalignant peripheral nerve sheath tumours (MPNSTs) of the trachea are extremely uncommon neoplasms with unknown genetic and clinical profiles. Only individual cases have been reported in the literature to date.Case presentationHere, we present a rare case of a 61-year-old female patient with a primary MPNST of the trachea who complained of irritating cough and progressively increasing breathlessness for 4 weeks. This patient initially underwent intraluminal resection of the mass and was misdiagnosed with clear cell sarcoma. Less than a year later, the mass relapsed, and the obstructive symptoms reappeared and gradually worsened. Debulking of the endotracheal tumour mass was performed once again, and an MPNST was definitively diagnosed. Open sleeve tracheal resection and tracheoplasty were later performed with curative intent. This patient was alive without recurrence at her six-month postoperative follow-up. We also compared the clinical outcomes of previously reported cases of MPNSTs and our case.ConclusionsThis paper emphasizes that thoracic surgeons should be aware that malignant peripheral nerve sheath tumours of the trachea can be misdiagnosed in clinical practice and must be included in the differential diagnosis of tracheal neoplasms.

A case report of primary multiple obturator nerve schwannomas

Primary multiple obturator nerve schwannomas originate from Schwann cells and are extremely rare. Patients with schwannomas are asymptomatic and a retroperitoneal schwannoma is often misdiagnosed as an adnexal mass. In the present study, we describe a 58-year-old woman in whom a right adnexal mass accompanied by endometrial polyp was found incidentally through transvaginal ultrasound. The mass was diagnosed as multiple obturator nerve schwannomas after laparoscopy. Immunohistochemical assay confirmed the schwannomas to be positive for SOX10. To our knowledge, this is the first report to demonstrate a case of multiple schwannomas originating from the obturator nerve and treated by laparoscopic resection.

Interleaved intramuscular stimulation with minimally overlapping electrodes evokes smooth and fatigue resistant forces

Objective. It is known that multi-site interleaved stimulation generates less muscle fatigue compared to single-site synchronous stimulation. However, in the limited number of studies in which intramuscular electrodes were used, the fatigue reduction associated with interleaved stimulation could not consistently be achieved. We hypothesize that this could be due to the inability to place the intramuscular electrodes used in interleaved stimulation in locations that minimize overlap amongst the motor units activated by the electrodes. Our objective in the present study was to use independent intramuscular electrodes to compare fatigue induced by interleaved stimulation with that generated by synchronous stimulation at the same initial force and ripple. Approach. In the medial gastrocnemius muscle of an anesthetized rabbit (n = 3), ten intramuscular hook wire electrodes were inserted at different distances from the nerve entry. Overlap was measured using the refractory technique and only three electrodes were found to be highly independent. After ensuring that forces obtained by both stimulation modalities had the same ripple and magnitude, fatigue induced during interleaved stimulation across three independent distal electrodes was compared to that obtained by synchronously delivering pulses to a single proximal electrode. Main results. Contractions evoked by interleaved stimulation exhibited less fatigue than those evoked by synchronous stimulation. Twitch force recruitment curves collected from each of the ten intramuscular electrodes showed frequent intermediate plateaus and the force value at these plateaus decreased as the distance between the electrode and nerve entry increased. Significance. The results indicate that interleaved intramuscular stimulation is preferred over synchronous intramuscular stimulation when fatigue-resistant and smooth forces are desired. In addition, the results suggest that the large muscle compartments innervated by the primary intramuscular nerve branches give rise to progressively smaller independent compartments in subsequent nerve divisions.

Vagus nerve stimulation for autoimmune rheumatic diseases.

The vagus nerve is the primary parasympathetic nerve of the autonomic nervous system, providing an extensive network of afferent and efferent parasympathetic innervation of the viscera.1 The vagus nerve comprises a bundle of approximately 80% afferent fibres and 20% efferent fibres, which control essential visceral functions including gastrointestinal motility, secretions, and heart rate.1 Vagus nerve activity is also a prominent component of several homeostatic axes including the cholinergic anti-inflammatory pathway, the brain–gut axis, and the hypothalamic–pituitary–adrenergic axis.

The Anatomic Feasibility of a Functional Chimeric Flap in Complex Abdominal Wall Reconstruction.

Dynamic and functional abdominal wall reconstruction (FAWR) remains a complex challenge. The ideal flap should have a minimal donor-site morbidity and cover a large surface area with motor and sensory capabilities. The goal was to investigate the feasibility of using a free chimeric flap with anterolateral thigh (ALT) and rectus femoris (RF) components pedicled only on the motor nerve branch. Ten fresh cadavers were dissected with a designed chimeric thigh flap including ALT and RF flaps. Anterolateral thigh was designed and raised with the lateral femoral cutaneous nerve integrated, and the descending branch of the lateral circumflex femoral artery was preserved. Rectus femoris was elevated and the common pedicle was dissected up to the femoral origin. Accompanying motor nerve branches were carefully dissected to their femoral origin. Twenty RF flaps were dissected and 9 were harvested as a true chimeric flap with ALT. The mean number of neurovascular bundles associated with RF flap was 2.11 ± 0.47, and the mean primary motor nerve average length was 9.40 ± 2.42 cm. The common vascular bundle in all 9 chimeric flaps was ligated, and the flap was rotated toward the abdomen pedicled only by primary motor nerve of the RF muscle. Nerve length was adequate for reach up to xiphoid area in all 20 flaps. This study demonstrates the feasibility of the chimeric ALT/RF muscle free flap pedicled only by the motor nerve branch, with adequate flap rotation. Even with the limitations in a live patient, this flap would be an excellent option for FAWR in the right patient.

Long-term results of Gamma Knife radiosurgery for facial nerve schwannomas

ABSTRACT Objective Long-term outcomes of eleven cases of facial nerve schwannoma were evaluated and the related literature was reviewed to determine the efficacy of Gamma Knife radiosurgery for treating patients with facial nerve schwannoma. Methods Eleven patients with facial nerve schwannoma (7 women and 4 men; mean age, 44.2 years; range, 19–73 years) underwent Gamma Knife radiosurgery. The most common symptoms were facial palsy (n = 10) and hearing loss (n = 7). Five patients presented with headache. Two patients had undergone prior resection. The patients’ clinical and radiographic data were evaluated retrospectively. Results For the 11 cases of facial nerve schwannoma, mean tumor volume was 3.1 cm3 (range, 0.4–7.4 cm3) and the mean marginal dose applied was 11.9 Gy (range, 11–13 Gy). The mean follow-up period was 84.3 months (range, 66–117 months). Tumor control was achieved in all patients. At the time of writing, four patients experienced tumor volume regression and the other seven were in stable condition. During follow-up, nine patients experienced no change in their facial function, two experienced deteriorated facial function, and none developed new facial palsy. Ten patients who had serviceable hearing prior to Gamma Knife radiosurgery retained their hearing. Conclusions Gamma Knife radiosurgery achieves excellent results with respect to tumor control for 7 years on average. In addition, Gamma Knife radiosurgery provides good results in facial nerve and hearing function at long term. Our series demonstrates that Gamma Knife radiosurgery is an effective and safe treatment for patients with either primary or residual facial nerve schwannoma.

Irritant-evoked activation and calcium modulation of the TRPA1 receptor.

The TRPA1 ion channel is expressed by primary afferent nerve fibers, where it functions as a low threshold sensor for structurally diverse electrophilic irritants ranging from small volatile environmental toxicants to endogenous algogenic lipids1. TRPA1 is also a ‘receptor-operated’ channel whose activation downstream of metabotropic receptors elicits inflammatory pain or itch, making it an attractive target for novel analgesic therapies2. However, we lack mechanistic insight into how TRPA1 recognizes and responds to electrophiles or cytoplasmic second messengers. Here, we show that electrophiles act through a two-step process in which modification of a highly reactive cysteine (C621) promotes reorientation of a cytoplasmic loop to enhance nucleophilicity and modification of a nearby cysteine (C665), thereby stabilizing the loop in an activating configuration. These actions modulate two restrictions controlling ion permeation, including widening of the selectivity filter to enhance calcium permeability and opening of a canonical gate at the cytoplasmic end of the pore. We propose a model to explain functional coupling between electrophile action and these control points. We also characterize a calcium binding pocket that is remarkably conserved across TRP channel subtypes and accounts for all aspects of calcium-dependent TRPA1 regulation, including potentiation, desensitization, and activation by metabotropic receptors. These findings provide a structural framework for understanding how a broad-spectrum irritant receptor is controlled by endogenous and exogenous agents that elicit or exacerbate pain and itch.

Comparison of peripheral nerve repair using ethyl-cyanoacrylate and conventional suture technique in a rat sciatic nerve injury model.

The aim of this study was to compare the outcomes of primary nerve repair using either ethyl-cyanoacrylate or conventional microsuture technique in a rat peripheral nerve injury model. In this study, a total of 30 Wistar Albino rats weighing between 220 and 275 g were used. The rats were randomly divided into three groups (10 in each), including one control (group 1) and two experimental groups (group 2, conventional microsuture repair; group 3, cyanoacrylate repair). In each group, the sciatic nerve was identified and transected. No further intervention was performed in group 1. The nerve was repaired using the epineural technique with a 10/0 atraumatic nylon in group 2 and synthetic cyanoacrylate adhesive in group 3. At the fifth postoperative week, needle electromyography (EMG) was performed to measure distal latency, combined muscle action potential (CMAP), and motor nerve conduction velocity (MNCV). Following the EMG recordings, animals were euthanized. Nerve samples were collected to evaluate vacuolar degeneration, fibrosis, and foreign body reaction histopathologically. In the EMG analysis, mean distal latency was significantly shorter in group 1 (0.85±0.09 ms) than in groups 2 (1.17±0.25 ms) (p=0.0052) and 3 (1.14±0.14 ms) (p=0.0026) while no significant differences existed between groups 2 and 3 (p>0.9999). The mean CMAP was greater in group 1 (10.5±0.35 mV) than in groups 2 (2.86±1.28 mV) (p=0.011) and 3 (2.16±1.34 mV) (p=0.0002), but there was no significant difference between groups 2 and 3 (p>0.9999). The mean MNCV was 53.5±5.95, 39.62±7.31, and 39.84±4.73 mm/sec in groups 1, 2, and 3, respectively. There was a significant difference between groups 1 and 2 (p=0.0052) and between 1 and 3 (p=0.0026), but not between 2 and 3 (p>0.9999). In the histopathological evaluation, the mean vacuolar degeneration score was 0, 2.12, and 1.88 in groups 1, 2, and 3, respectively. No obvious difference was observed between groups 2 and 3 (p=0.743). The mean fibrosis score was 0, 1.62, and 1.77 in groups 1, 2, and 3, respectively. There was no significant difference between groups 2 and 3 (p=0.888). The mean foreign body reaction score was 0, 2.5, and 2.44 in groups 1, 2, and 3, respectively. No difference was present between groups 2 and 3 (p=0.743). Primary nerve repair using the cyanoacrylate adhesive may provide similar electrophysiological and histopathological results as compared to the conventional microsuture repair.

Predicting postoperative delirium after microvascular decompression surgery with machine learning

ObjectiveThe aim of this study was to predict early delirium after microvascular decompression using machine learning. DesignRetrospective cohort study. SettingSecond Hospital of Lanzhou University. PatientsThis study involved 912 patients with primary cranial nerve disease who had undergone microvascular decompression surgery between July 2007 and June 2018. InterventionsNone. MeasurementsWe collected data on preoperative, intraoperative, and postoperative variables. Statistical analysis was conducted in R, and the model was constructed with python. The machine learning model was run using the following models: decision tree, logistic regression, random forest, gbm, and GBDT models. Results912 patients were enrolled in this study, 221 of which (24.2%) had postoperative delirium. The machine learning Gbm algorithm finds that the first five factors accounting for the weight of postoperative delirium are CBZ use duration, hgb, serum CBZ level measured 24 h before surgery, preoperative CBZ dose, and BUN. Through machine learning five algorithms to build prediction models, we found the following values for the training group: Logistic algorithm (AUC value = 0.925, accuracy = 0.900); Forest algorithm (AUC value = 0.994, accuracy = 0.948); GradientBoosting algorithm (AUC value = 0.994, accuracy = 0.970) and DecisionTree algorithm (aucvalue = 0.902, accuracy = 0.861); Gbm algorithm (AUC value = 0.979, accuracy = 0.944). The test group had the following values: Logistic algorithm (aucvalue = 0.920, accuracy = 0.901); DecisionTree algorithm (aucvalue = 0.888, accuracy = 0.883); Forest algorithm (aucvalue = 0.963, accuracy = 0.909); GradientBoostingc algorithm (aucvalue = 0.962, accuracy = 0.923); Gbm algorithm (AUC value = 0.956, accuracy = 0.920). ConclusionMachine learning algorithms predict the occurrence of delirium after microvascular decompression with an accuracy rate of 96.7%. And the major risk factors for the development of post-cardiac delirium are carbamazepine, hgb, and BUN.