Evolutionary genetics of pulmonary anatomical adaptations in deep-diving cetaceans.

BACKGROUND: Cetaceans, having experienced prolonged adaptation to aquatic environments, have undergone evolutionary changes in their respiratory systems. This process of evolution has resulted in the emergence of distinctive phenotypic traits, notably the abundance of elastic fibers and thickened alveolar walls in their lungs, which may facilitate alveolar collapse during diving. This structure helps selective exchange of oxygen and carbon dioxide, while minimizing nitrogen exchange, thereby reducing the risk of DCS. Nevertheless, the scientific inquiry into the mechanisms through which these unique phenotypic characteristics govern the diving behavior of marine mammals, including cetaceans, remains unresolved. RESULTS: This study entails an evolutionary analysis of 42 genes associated with pulmonary fibrosis across 45 mammalian species. Twenty-one genes in cetaceans exhibited accelerated evolution, featuring specific amino acid substitutions in 14 of them. Primarily linked to the development of the respiratory system and lung morphological construction, these genes play a crucial role. Moreover, among marine mammals, we identified eight genes undergoing positive selection, and the evolutionary rates of three genes significantly correlated with diving depth. Specifically, the SFTPC gene exhibited convergent amino acid substitutions. Through in vitro cellular experiments, we illustrated that convergent amino acid site mutations in SFTPC contribute positively to pulmonary fibrosis in marine mammals, and the presence of this phenotype can induce deep alveolar collapse during diving, thereby reducing the risk of DCS during diving. CONCLUSIONS: The study unveils pivotal genetic signals in cetaceans and other marine mammals, arising through evolution. These genetic signals may influence lung characteristics in marine mammals and have been linked to a reduced risk of developing DCS. Moreover, the research serves as a valuable reference for delving deeper into human diving physiology.

Real-time imaging of decompression gas bubble growth in the spinal cord of live rats.

PURPOSE: To observe the growth and resolution of decompression gas bubbles in the spinal cord of live rats in real time using MRI. METHODS: We constructed an MRI-compatible pressure chamber system to visualize gas bubble dynamics in deep tissues in real time. The system pressurizes and depressurizes rodents inside an MRI scanner and monitors their respiratory rate, heart rate, and body temperature while providing gaseous anesthesia under pressure during the experiments. RESULTS: We observed the formation of decompression gas bubbles in the spinal cord of rats after compression to 7.1 bar absolute and rapid decompression inside the MRI scanner while maintaining continuous gaseous anesthesia and vital monitoring. CONCLUSION: We have shown the direct observation of decompression gas bubble formation in real time by MRI in live, anesthetized rats.

Cholangitis and Interruptions of Neoadjuvant Chemotherapy Associate with Reduced Overall and Progression-Free Survival in Pancreatic Cancer.

BACKGROUND: Interrupting chemotherapy may explain the reduced overall survival (OS) in patients with pancreatic cancer (PC) with cholangitis. Endoscopic biliary decompression (BD) with metallic stents results in fewer chemotherapy interruptions and a lower cholangitis rate compared with plastic stents. We aimed to determine the impact of cholangitis, neoadjuvant treatment (NAT) interruptions and biliary stent choice on PC patients' survival. METHODS: We conducted a retrospective analysis of 162 patients with cancer of the head of the pancreas undergoing pancreatoduodenectomy after NAT and BD documenting progression-free survival (PFS) and OS. Data on BD, cholangitis, stent type, surgical radicality, and chemotherapy were collected. Survival was estimated based on the Kaplan-Meier method by using the log-rank test and multivariate Cox regression analysis. RESULTS: Median OS and PFS for patients with cholangitis (n = 33, 20%) were 26 and 8 months (95% confidence interval [CI] 20-32 and 5-10 months), respectively, compared with 36 and 17 months (95% CI 31-41 and 12-21 months; p < 0.001 for OS; p = 0.002 for PFS) for patients without cholangitis. Among patients without NAT interruptions median OS and PFS were 35 and 17 months (95% CI 31-40 and 12-21 months), falling to 26 and 7 months (95% CI 18-30 and 5-10 months) among those who experienced an NAT interruption caused by biliary stent failure (n = 26, 16%) (p = 0.039 for OS; p < 0.001 for PFS). We found no difference in OS or PFS between stent types. CONCLUSIONS: Cholangitis and NAT interruptions reduce OS and PFS among PC patients.

Decoding the Conundrum: Navigating Intra-operatively Encountered Suspicious Gallbladder Wall Thickening with Laparoscopic Transhepatic Needle Decompression and Beyond Cystic Plate Cholecystectomy.

BACKGROUND: Suspicious gallbladder wall thickening encountered during laparoscopic cholecystectomy poses challenges in its management. This study aims to address this problem by proposing a technique that involves laparoscopic transhepatic needle decompression and modified cystic plate cholecystectomy. METHODS: In this report, we describe the case of a 36-year-old female with symptomatic gallstone disease and ultrasound findings of a well-distended gallbladder with a uniform wall thickness. Diagnostic laparoscopy revealed a distended, tense gallbladder with suspicious areas of thickness. Transhepatic aspiration was performed for gallbladder decompression, followed by modified cystic plate cholecystectomy with preservation of the thin rim of liver tissue over the cystic plate. The gallbladder was removed in a specimen bag, and final histopathology showed a hyalinized gallbladder wall with calcification and pyloric gland metaplasia, with liver tissue adhered to the gallbladder wall (Video). RESULTS: The proposed technique aimed to minimize the risk of bile spillage and violation of oncological planes while maintaining surgical integrity. It offers a middle path between standard and extended cholecystectomy, reducing the chance of over- or under-treatment. This approach ensures patient safety, minimizes the need for conversion to open surgery, and preserves the tumour-tissue interface. CONCLUSION: Intraoperatively encountered suspicious gallbladder wall thickening can be effectively managed with laparoscopic transhepatic needle decompression and modified cystic plate cholecystectomy.

Morphological features of the greater occipital nerve and its possible importance for interventional procedures.

Being one of the most prevalent neurological symptoms, headaches are burdensome and costly. Blocks and decompression surgeries of the greater occipital nerve (GON) have been frequently used for migraine, cervicogenic headache, and occipital neuralgia which are classified under headache by International Headache Society. Knowledge of complex anatomy of GON is crucial for its decompression surgery and block. This study was performed to elucidate anatomical features of this nerve in detail. Forty-one cadavers were dissected bilaterally. According to its morphological features, GON was classified into four main types that included 18 subtypes. Moreover, potential compression points of the nerve were defined. The number of branches of the GON up to semispinalis capitis muscle and the number of its branches that were sent to this muscle were recorded. The most common variant was that the GON pierced the aponeurosis of the trapezius muscle, curved around the lower edge of the obliquus capitis inferior muscle, and was loosely attached to the obliquus capitis inferior muscle (Type 2; 61 sides, 74.4%). In the subtypes, the most common form was Type 2-A (44 sides, 53.6%), in which the GON pierced the aponeurosis of each of the trapezius muscle and fibers of semispinalis muscle at one point and there was a single crossing of the GON and occipital artery. Six potential compression points of the GON were detected. The first point was where the nerve crossed the lower border of the obliquus capitis inferior muscle. The second and third points were at its piercing of the semispinalis capitis muscle and the muscle fibers/aponeurosis of the trapezius, respectively. Fourth, fifth, and sixth compression points of GON were located where the GON and occipital artery crossed each other for the first, second, and third times, respectively. On 69 sides, 1-4 branches of the GON up to the semispinalis capitis muscle were observed (median = 1), while 1-4 branches of GON were sent to the semispinalis capitis muscle on 67 sides (median = 1). The novel anatomical findings described in this study may play a significant role in increasing the success rate of invasive interventions related with the GON.

Contemporary outcomes of surgical decompression for functional popliteal entrapment syndrome.

BACKGROUND: Functional popliteal entrapment syndrome (FPES) is an under-recognized source of leg pain caused by dynamic compression of the popliteal vessels by surrounding musculature in the absence of anatomic abnormality. Late recognition and difficulty capturing this entity across imaging modalities can lead to significant morbidity in an often young and active patient population. Surgical outcomes and optimal diagnostic strategies remain uncertain. METHODS: We performed a retrospective cohort study of all patients undergoing surgical decompression for FPES at an academic medical center between 2018 and 2022. Preoperative symptoms, patient characteristics, imaging, operative details, and follow-up were captured. The primary outcome was symptomatic improvement at last clinic visit. Secondary outcomes included symptomatic improvement at 6 months and postoperative complications. RESULTS: A total of 24 extremities (16 patients) were included. The mean ± standard deviation age was 23.3 ± 6.4 years and 75.0% of patients were female. The median symptom duration before decompression was 27 months (interquartile range, 10.7-74.6 months). Preoperative symptom severity in the affected extremity was as follows: 33.3% limited from peak exercise, 25% unable to exercise, and 41.7% with debilitating symptoms that affected activities of daily living. Preoperative imaging with provocative maneuvers included duplex ultrasound (87.5%), magnetic resonance angiography (100%), and digital subtraction angiography (100%). Using digital subtraction angiography as the gold standard, the sensitivity for detection of FPES was 85.7% for duplex examination and 58.3% for magnetic resonance angiography. The median follow-up was 451 days (interquartile range, 281-635 days). Most patients demonstrated durable improvement in the affected extremity, with 29.2% realizing complete resolution of symptoms and 37.5% reporting symptomatic improvement at last clinic visit for a total of 66.7%; 20.8% had initial improvement, but developed recurrent symptoms and were found to have elevated compartment pressures consistent with chronic exertional compartment syndrome and were treated with formal fasciotomy. Repeat decompression was required in one extremity (4.2%) owing to recurrent symptoms. Two patients (8.3%) had minimal or no improvement in their affected extremity and workup for the cause of continued discomfort was ongoing. CONCLUSIONS: Delays in diagnosis of FPES are common. Provocative maneuvers until replication of symptoms across multiple imaging modalities may be necessary to reliably identify the disease process. Surgical decompression improved or completely resolved symptoms in two-thirds of extremities. Treating physicians should maintain suspicion for comorbid chronic exertional compartment syndrome, especially if symptoms recur or persist after decompression.

Eccentric exercise before a 90 min exposure at 24,000 ft increases decompression strain depending on body region but not total muscle mass recruited.

Eccentric upper-body exercise performed 24 h prior to high-altitude decompression has previously been shown to aggravate venous gas emboli (VGE) load. Yet, it is unclear whether increasing the muscle mass recruited (i.e., upper vs. whole-body) during eccentric exercise would exacerbate the decompression strain. Accordingly, this study aimed to investigate whether the total muscle mass recruited during eccentric exercise influences the decompression strain. Eleven male participants were exposed to a simulated altitude of 24,000 ft for 90 min on three separate occasions. Twenty-four hours before each exposure, participants performed one of the following protocols: (i) eccentric whole-body exercise (ECCw; squats and arm-cycling exercise), (ii) eccentric upper-body exercise (ECCu; arm-cycling), or (iii) no exercise (control). Delayed onset muscle soreness (DOMS) and isometric strength were evaluated before and after each exercise intervention. VGE load was evaluated at rest and after knee- and arm-flex provocations using the 6-graded Eftedal-Brubakk scale. Knee extensor (-20 ± 14%, P = 0.001) but not elbow flexor (-12 ± 18%, P = 0.152) isometric strength was reduced 24 h after ECCw. ECCu reduced elbow flexor isometric strength at 24 h post-exercise (-18 ± 10%, P < 0.001). Elbow flexor DOMS was higher in the ECCu (median 6) compared with ECCw (5, P = 0.035). VGE scores were higher following arm-flex provocations in the ECCu (median (range), 3 (0-4)) compared with ECCw (2 (0-3), P = 0.039) and control (0 (0-2), P = 0.011), and in ECCw compared with control (P = 0.023). VGE were detected earlier in ECCu (13 ± 20 min) compared with control (60 ± 38 min, P = 0.021), while no differences were noted between ECCw (18 ± 30 min) and control or ECCu. Eccentric exercise increased the decompression strain compared with control. The VGE load varied depending on the body region but not the total muscle mass recruited. HIGHLIGHTS: What is the central question of this study? Does exercise-induced muscle damage (EIMD) resulting from eccentric exercise influence the presence of venous gas emboli (VGE) during a 90 min continuous exposure at 24,000 ft? What is the main finding and its importance? EIMD led to an earlier manifestation and greater VGE load compared with control. However, the decompression strain was dependent on the body region but not the total muscle mass recruited.

Predicting long-term outcomes in patients with classical trigeminal neuralgia following microvascular decompression with an MRI-based radiomics nomogram: a multicentre study.

OBJECTIVES: This study aimed to develop a clinical-radiomics nomogram to predict the long-term outcomes of patients with classical trigeminal neuralgia (CTN) following microvascular decompression (MVD). MATERIALS AND METHODS: This retrospective study included 455 patients with CTN who underwent MVD from three independent institutions A total of 2030 radiomics features from the cistern segment of the trigeminal nerve were extracted computationally from the three-dimensional steady-state free precession and three-dimensional time-of-flight magnetic resonance angiography sequences. Using the least absolute shrinkage and selection operator regression, 16 features were chosen to develop radiomics signatures. A clinical-radiomics nomogram was subsequently developed in the development cohort of 279 patients via multivariate Cox regression. The predictive performance and clinical application of the nomogram were assessed in an external cohort consisting of 176 patients. RESULTS: Sixteen highly outcome-related radiomics features extracted from multisequence images were used to construct the radiomics model, with concordance indices (C-index) of 0.804 and 0.796 in the development and test cohorts, respectively. Additionally, a clinical-radiomics nomogram was developed by incorporating both radiomics features and clinical characteristics (i.e., pain type and degree of neurovascular compression) and yielded higher C-indices of 0.865 and 0.834 in the development and test cohorts, respectively. K‒M survival analysis indicated that the nomogram successfully stratified patients with CTN into high-risk and low-risk groups for poor outcomes (hazard ratio: 37.18, p < 0.001). CONCLUSION: Our study findings indicated that the clinical-radiomics nomogram exhibited promising performance in accurately predicting long-term pain outcomes following MVD. CLINICAL RELEVANCE STATEMENT: This model had the potential to aid clinicians in making well-informed decisions regarding the treatment of patients with CTN. KEY POINTS: Trigeminal neuralgia recurs in about one-third of patients after undergoing MVD. The clinical-radiomics nomogram stratified patients into high- and low-risk groups for poor surgical outcomes. Using this nomogram could better inform patients of recurrence risk and allow for discussion of alternative treatments.

Long-term outcomes of Gamma Knife radiosurgery in treating glossopharyngeal neuralgia.

Glossopharyngeal neuralgia (GPN) is an unusual disorder causing severe, brief pain episodes in the areas supplied by the glossopharyngeal nerve. Initial treatment involves medications like carbamazepine, but if these are ineffective or cause side effects, interventional pain management techniques or surgery may be considered. Gamma Knife radiosurgery is becoming popular in managing GPN due to its lower risk of complications than surgical interventions like microvascular decompression or rhizotomy. In this retrospective case series, we examined the outcomes of Gamma Knife radiosurgery in eight patients with GPN. The decision to utilize Gamma Knife radiosurgery was made following specific criteria, including failed surgical interventions, patient preference against surgery, or contraindications to surgical procedures. Patients were administered radiation doses within the range of 80 to 90 Gy, targeting either the cisternal glossopharyngeal nerve or glossopharyngeal meatus of the jugular foramen. Evaluations were conducted before the Gamma Knife radiosurgery; at 3, 6, and 12 months after Gamma Knife radiosurgery; and annually thereafter. Pain severity was assessed using the modified Barrow Neurological Institute scale grades, with patients achieving grade I-IIIa considered to have a good treatment outcome and grade IV-V to have a poor treatment outcome. Pain control and absence of radiosurgery-related complications were primary endpoints. The median age of the patients was 46.5 years, varying from 8 to 72 years. The median duration of pain was 32 months (range, 12-120 months). All patients, except one, were on polydrug therapy. All cases exhibited preoperative grade V pain. The median follow-up duration after Gamma Knife radiosurgery was 54.5 months, varying from 14 to 90 months. The overall clinical assessments revealed a gradual neurological improvement, particularly within the first 8.5 weeks (range, 1-12 weeks). The immediate outcomes at 3 months revealed that all patients (8/8, 100%) experienced pain relief, with 25% (2/8) achieving a medication-free status (Grade I). Three patients (37%) experienced a recurrence during the follow-up and were managed with repeat Gamma Knife radiosurgery (n = 2) and radiofrequency rhizotomy (n = 1). At the last follow-up, 88% (7/8) of patients had pain relief (Grades I-IIIa), with three (37%) achieving a medication-free status (Grade I). No adverse events or neurological complications occurred. The patient who underwent radiofrequency rhizotomy continued to experience inadequately controlled pain despite medication (Grade IV). Gamma Knife radiosurgery is a non-invasive, efficacious treatment option for idiopathic GPN, offering short- and long-term relief without permanent complications.

Surgical Management of Headache Disorders - A Systematic Review of the Literature.

PURPOSE OF REVIEW: This review article critically evaluates the latest advances in the surgical treatment of headache disorders. RECENT FINDINGS: Studies have demonstrated the effectiveness of innovative screening tools, such as doppler ultrasound, pain drawings, magnetic resonance neurography, and nerve blocks to help identify candidates for surgery. Machine learning has emerged as a powerful tool to predict surgical outcomes. In addition, advances in surgical techniques, including minimally invasive incisions, fat injections, and novel strategies to treat injured nerves (neuromas) have demonstrated promising results. Lastly, improved patient-reported outcome measures are evolving to provide a framework for comparison of conservative and invasive treatment outcomes. Despite these developments, challenges persist, particularly related to appropriate patient selection, insurance coverage, delays in diagnosis and surgical treatment, and the absence of standardized measures to assess and compare treatment impact. Collaboration between medical/procedural and surgical specialties is required to overcome these obstacles.

Surgical approaches for pudendal nerve entrapment: insights from a systematic review and meta-analysis.

BACKGROUND: Pudendal nerve entrapment (PNE) is an underdiagnosed condition affecting a spectrum of pelvic functions, primarily pain, as outlined by Nantes diagnostic criteria. Although numerous surgical decompression techniques are available for its management, consensus on efficacy and safety is lacking. This study conducts a systematic review and meta-analysis to assess the efficacy and complication rates of the main surgical decompression techniques. METHODS: A comprehensive literature search was conducted in PubMed®, Embase®, Web of Science®, and ClinicalTrails.gov® on 19th of April 2023. Initial screening involved title and abstract evaluation, with subsequent retrieval and assessment of abstracts and full-text articles. Studies assessing pain outcomes before and after surgical release of the pudendal nerve were included. Studies without full-text, focusing on diagnostic methods or with outcomes relating solely to LUTS, digestive symptoms, or sexual dysfunction, were excluded. Risk of bias assessement was conducted using the National Institute of Health (NIH) Study Quality Assessment tool. Studies were categorized based on three surgical techniques: perineal, transgluteal, and laparoscopic transperitoneal. Random-effects meta-analysis with subgroup analysis were used. Meta-regression analyses were conducted to investigate the influence of covariates on the observed outcomes. RESULTS: Nineteen studies, comprising 810 patients, were included. The overall significant pain relief rate across all techniques was estimated at 0.67 (95% CI 0.54 to 0.78) with considerable heterogeneity (I2 = 80.4%). Subgroup analysis revealed success rate for different techniques: laparoscopic (0.91, 95% CI 0.64 to 0.98), perineal (0.69, 95% CI 0.52 to 0.82), and transgluteal (0.50, 95% CI 0.37 to 0.63). The laparoscopic technique exhibited a complication rate of 16.0%. Meta-regression indicated that patient age and median follow-up significantly influenced outcomes. CONCLUSION: While comparing surgical techniques is challenging, this meta-analysis highlights important outcome differences. The laparoscopic technique appears most promising for pain improvement. However, the study also emphasizes the need for further robust, long-term research due to significant heterogeneity across studies and prevelent risk of bias. PROSPERO database: CRD42023496564.

Clinical application of super-low-positioned intestinal decompression tube in the treatment of intestinal obstruction: a pilot study.

OBJECTIVE: This study aimed to evaluate the clinical application and efficacy of a super-low-positioned intestinal decompression tube in the treatment of intestinal obstruction. METHODS: A total of 130 patients with postoperative small bowel obstruction were included in this study. The patients were divided into a super-low-positioned intestinal decompression group and a conventional intestinal decompression group. The clinical data, treatment outcomes, and complications were compared between the two groups. RESULTS: The technical success rate of placing the super-low-positioned intestinal decompression tube was 100%, with no intraoperative complications. The patients in the super-low-positioned intestinal decompression group had a significantly shorter hospital stay (8.3 ± 5.2 vs 17.7 ± 13.3, P < 0.001) and a higher non-operative treatment success rate (83.6% vs 57.9%, P = 0.001) compared to the conventional intestinal decompression group. Multivariate logistic regression analysis showed that the placement of a super-low-positioned intestinal decompression tube was an independent protective factor for treatment outcomes (P = 0.001). The hospital stay was significantly shorter in the super-low-positioned intestinal decompression group compared to the conventional group in both successful non-operative treatment patients (6.9 ± 3.0 vs 11.2 ± 7.5, P < 0.001) and failed non-operative treatment patients (16.2 ± 7.4 vs 26.6 ± 14.4, P < 0.001). The super-low-positioned intestinal decompression tube effectively relieved the "Self-strangulation" phenomenon in patients with intestinal obstruction. CONCLUSION: The super-low-positioned intestinal decompression tube is a safe and effective method for the treatment of intestinal obstruction, with better treatment outcomes and shorter hospital stays compared to conventional intestinal decompression. Further prospective studies are needed to validate these findings.

Comparison of surgical effect in active and inactive Dysthyroid Optic Neuropathy after Endoscopic Transnasal Medial Orbital Decompression.

PURPOSE: To evaluate and compare the changes in orbital soft tissue volume and visual function after endoscopic transnasal medial orbital decompression in patients with active and inactive dysthyroid optic neuropathy (DON). METHODS: This prospective, cohort study recruited 112 patients (112 eyes) with DON who were divided into an active and inactive DON group (56 eyes each) by clinical activity scores. All patients underwent endoscopic transnasal medial orbital decompression. The pre- and post-operative orbital soft tissue volumes were measured with high-resolution computed tomography (CT) using Mimics software. Visual function, including best-corrected visual acuity (BCVA), visual field (VF), and visual evoked potential (VEP), was recorded before and after surgery. RESULTS: Preoperatively, compared with the inactive DON group, the active DON group had greater extraocular muscle volume (EMV) and EMV/orbital volume (OV) ratio, but worse BCVA, VF, and exophthalmos. Postoperatively, although the EMV slightly increased, with the enlarged medial rectus muscle contributing dramatically, the EMV/OV ratio decreased in patients with DON. Besides, visual function including BCVA, VF, VEP and exophthalmos was also improved in both groups after surgery. There were no significant differences in postoperative OV; EMV; EMV/OV ratio; and the BCVA, VF, and VEP parameters between both groups (all P > 0.05). CONCLUSION: Patients with DON who did not respond well to steroids, regardless of disease activity, may benefit from orbital decompression via the decrease in the proportion of EMV in OV, especially patients with active DON, who showed more improved visual function than patients with inactive DON.

Robot assisted exploration of the Alcock canal: a novel surgical technique.

OBJECTIVE: To demonstrate a safe and reproducible surgical approach to the Alcock canal with a full decompression of the pudendal nerve. SETTING: Pudendal neuralgia, a condition causing debilitating pelvic pain, is traditionally managed through a trans-gluteal incision.1-2 This surgical approach offers limited visualization and ability for nerve decompression.3 With the current technique, a full exposure and decompression of the pudendal nerve was achieved. PARTICIPANTS: A 44-year-old para 2 with symptoms of left pudendal neuralgia. INTERVENTIONS: A 44-year-old para 2 presented with burning vaginal pain radiating to the left groin that was aggravated with sitting. She underwent a robotic-assisted left sacrospinous ligament transection and fasciotomy of the obturator internus muscle for suspected pudendal neuralgia. The surgery was performed with three robotic ports using the daVinci® Xi robotic system. CONCLUSION: With the enhanced access to the pudendal nerve provided by the novel surgical technique demonstrated in this study, a more comprehensive nerve decompression can be performed. This technique was successfully applied to a patient with pudendal neuralgia. There were no immediate intra-operative or post-operative complications. In short-term follow-up, the patient had significant relief of preoperative symptoms. While all surgical procedures for pudendal neuralgia have a risk of pudendal nerve and vessel injury,4 the presented technique has the potential to limit these risks by providing an enhanced view of the relevant anatomy. Future adaptation and refinement of this technique may contribute to the advancement of the surgical management of pudendal neuralgia.

Alteration of major venous drainage routes in a patient with achondroplasia after ventriculoperitoneal shunt placement.

Achondroplasia is the most common form of dwarfism, caused by a mutation in fibroblast growth factor receptor 3 gene, leading to multiple pathological conditions. Herein, we present a case of an infant with achondroplasia associated with hydrocephalus and severe foramen magnum stenosis. Computed tomography (CT) venography showed prominent suboccipital emissary veins comprising major venous drainage routes and hypoplastic transverse sinuses, which increased the risk of foramen magnum decompression. The infant was initially treated with ventriculo-peritoneal (VP) shunt. After 8 months, CT venography showed regression of suboccipital emissary veins and more prominent transverse sinuses. Subsequently, foramen magnum decompression was safely performed without sacrificing major venous drainage routes.

Predicting the presence of 4th ventricular outlet obstruction in Chiari I Malformation.

INTRODUCTION: A subset of children with Chiari 1 malformation (CM-1) have a 4th ventricle arachnoid veil-a thin membrane covering the outlet of the 4th ventricle. Studies suggest that failure to disrupt this veil during posterior fossa decompression can reduce the likelihood of syringomyelia resolution. However, there is no reliable method for predicting the presence of the veil without direct surgical exploration. This study aims to evaluate the association between pre-operative symptoms, radiographic measurements, and the arachnoid veil. METHODS: A retrospective review of an institutional database of children evaluated for CM-I was conducted. For patients treated with surgery, operative notes were reviewed to determine if an arachnoid veil was present. Logistic regression was used to test for relationship of clinical variables and radiographic measurements with the presence of an arachnoid veil. RESULTS: Out of 997 children with CM-1, 226 surgical patients were included in the analysis after excluding those with inadequate documentation. An arachnoid veil was found in 23 patients (10.2%). Larger syrinx, spinal canal, and thecal sac diameters were significantly associated with the presence of a veil, with odds ratios of 1.23 (95% CI 1.2-1.48; p = 0.03), 1.27 (95% CI 1.02-1.59; p = 0.03), and 1.35 (95% CI 1.03-1.77; p = 0.03), respectively. No significant associations were found with any signs or symptoms. CONCLUSIONS: Arachnoid veil was present in 10% of cases. Radiographic measurements indicating larger syrinx size were the only variables found to be significantly associated with an arachnoid veil. Exploration of the 4th ventricular outlet is recommended for CM-I decompression in the setting of expansile syringomyelia.

Peripheral nerve decompression for pain relief in the setting of previous obstetrical brachial plexus injury: a retrospective case series.

PURPOSE: In children with previous obstetrical brachial plexus injury (OBPI), upper extremity pain is present in 45 to 66% of patients. Recent literature reports this as musculoskeletal or neuropathic in nature. The purpose of the study is to demonstrate that peripheral nerve decompression, and neurolysis may be an effective treatment for patients with upper extremity pain in the context of previous OBPI. METHODS: A retrospective chart review was performed on patients undergoing peripheral nerve decompression and neurolysis after OBPI by senior author. The primary outcome assessed was pain, and secondary outcome measure was range of motion of the wrist and elbow. Outcome measures were assessed preoperatively as well as at their subsequent follow-up. RESULTS: Six patients were included, with a mean age of 14 years old at time of decompression. Three patients underwent median nerve, two patients underwent ulnar nerve, and one patient underwent posterior interosseous nerve decompression. There was a substantial improvement in pain post-operatively, demonstrated by reduction or resolution of subjective pain in all patients and resolution of Tinel's sign. There was a modest improvement in range of motion. CONCLUSION: This study demonstrates an improvement in subjective pain and range of motion after decompression and neurolysis in small subset of OBPI patients. It generates the hypothesis that peripheral nerve compression is a source of pain that can be addressed in this population. Future research should focus on confirming this hypothesis and assessing treatment options on a larger scale.

Retroflexed dens in paediatric Chiari 1 patients and implications: Single centre retrospective study.

INTRODUCTION: Chiari 1 malformation and hind brain hernia can be associated with skull base and craniocervical anomalies. One of the more recently associated anomalies is a retroverted or retroflexed odontoid process or dens. We conducted a retrospective study of our operated symptomatic and conservatively managed asymptomatic Chiari cohort to assess the impact of dens retroflexion on rate of revision or cerebrospinal fluid diversion following primary foramen magnum decompression (FMD). METHODS: We undertook a retrospective study of all foramen magnum decompression (FMD) cases for Chiari type 1 malformation performed over a 15-year period in a single tertiary paediatric neurosurgical unit. For comparison, non-operated asymptomatic Chiari cases were considered as reference cohort. Information gathered included: demographics, age, sex, length of cerebellar tonsils below McRae's line, pB-C2 distance (a line drawn perpendicular to one drawn between the basion and the posterior aspect of the C2 body), angle of retroflexion (angle formed between a line drawn through the odontoid synchondrosis and its intersection with a line drawn from the tip of the odontoid process) and angle of retroversion (angle formed between the line drawn from the base of C2 and its intersection with a line drawn from the tip of the odontoid process). Grade of retroflexion was measured using pre-operative mid-sagittal MR images and classified as grade 0 (> 90°), grade 1 (85°-89°); grade 2 (80°-84°) and grade 3 (< 80°). The rates for redo surgery or need for cerebrospinal fluid (CSF) diversion were obtained from clinical records and compared in the operated and non-operated groups. RESULTS: One hundred twenty-six Chiari 1 patients were included in this study with adequate imaging. Sixty-five patients were in the non-operated asymptomatic cohort with 61 patients in the operated symptomatic cohort. Mean age of non-operated cohort was 10.2 years with M:F ratio (30:35). Mean cerebellar tonsillar length below McRae's line was 10.3 mm. 7.7% of this cohort had associated syrinx. Mean angles of retroversion and retroflexion were 76 and 78°, respectively. Retroflexion grades included (9.2% grade 1, 35% grade 2 and 52.3% grade 3). pB-C2 distance was 6.8 mm. Mean age of operated cohort was 11.3 years, with M:F ratio (21:40). Mean cerebellar tonsillar length below McRae's line was 15 mm. 45.9% of this cohort had associated syrinx. Mean angles of retroversion and retroflexion were 73 and 74.5°, respectively. Retroflexion grades included (4.9% grade 1, 16.5% grade 2 and 78.6% grade 3). pB-C2 distance was 6.9 mm. No association was identified between retroflexion grade and rate of revision or CSF diversion following primary foramen magnum decompression. CONCLUSION: The operated Chiari 1 cohort had more retroflexed dens, longer tonsils and associated syrinx compared to the non-operated asymptomatic cohort.

Navigating the complexities of encephalocraniocutaneous lipomatosis: a case series and review.

INTRODUCTION: Encephalocraniocutaneous lipomatosis (ECCL) is a rare congenital syndrome with complex skin, eye, and central nervous system (CNS) symptoms. Diagnosis and treatment are challenging due to its rarity and diverse manifestations. It often involves issues like porencephalic cysts, cortical atrophy, and low-grade gliomas in the CNS, resulting in developmental delays. The spinal cord is frequently affected, leading to problems like medullary compression and radiculopathy, causing back pain and sensory/motor deficits. Surgical interventions are reserved for symptomatic cases to address hydrocephalus or alleviate spinal lipomas. This article reviews a case series to assess surgical risks and neurological outcomes. CASE SERIES: We present a case series ECCL, focusing on the diffuse lipomatosis of the spinal cord and the intricate surgical procedures involved. A multi-stage surgical approach was adopted, with continuous neuromonitoring employed to safeguard motor pathways. We discuss clinical characteristics, imaging studies, and indications for neurosurgical interventions. DISCUSSION: ECCL is a complex syndrome. Diagnosis is challenging and includes clinical evaluation, neuroimaging, and genetic testing. Treatment targets specific symptoms, often requiring surgery for issues like lipomas or cerebral cysts. Surgery involves laminectomies, spinal fusion, and motor pathway monitoring. Thorough follow-up is crucial due to potential CNS complications like low-grade gliomas. Hydrocephalus occurs in some cases, with endoscopic third ventriculostomy (ETV) preferred over ventriculoperitoneal shunt placement. CONCLUSION: Neurosurgery for ECCL is for symptomatic cases. ETV is preferred for hydrocephalus, while the treatment for lipoma is based on the presence of symptoms; the follow-up should assess growth and prevent deformities.

Surgical management of Chiari II malformation: a systematic review of literature.

PURPOSE: Chiari II malformation (CM-II) is a congenital malformation of the posterior fossa associated with myelomeningocele. Of the symptomatic patients, 10-33% require surgical treatment. To this date, there is not a consensus about the best surgical technique, and whether to do duroplasty. METHODS: A literature search of the PubMed database and crossed references was performed, per PRISMA guidelines. Data regarding demographic features, extent of cervicomedullary deformity, clinical presentation, surgical techniques, and clinical outcomes were extracted. Pearson's chi-squared test was applied. The p-values under 0.05 were considered statistically significant. RESULTS: Twenty studies (N = 330) were analyzed. C3 and C4 levels represented 56.4% of the lowest tonsil displacement. The most reported symptom was dysphagia/swallowing dysfunction (53.8%). Suboccipital craniectomy (SOC) and cervical spine expansion (CSE) with duroplasty were the most reported technique. Dural augmentation was performed in 57.4% of the patients. After surgery, 59.6% observed an improvement in symptoms and quality of life, 12.5% were unchanged, and 27.8% had a worsened clinical status. The mortality rate was 2.5% during the first month after surgery, and 17.4% at the last follow-up evaluation. Patients who underwent CSE presented a better clinical outcome (p = 0.002). The SOC procedure could not be correlated with symptom improvement (p = 0.06). CONCLUSION: CM-II is associated with high morbidity and mortality. An early onset symptomatic CM-II demands intervention, which provided an improvement of outcome in most patients included in this review. The best surgical technique and the exact effect of the surgical management of CM-II on mortality are not yet clear.