Tomodensitometric Bone Anatomy of The Intervertebral Foramen of The Lower Cervical Spine: Measurements and Comparison of Foraminal Volume in Healthy Individuals and Patients Suffering from Cervicobrachial Neuralgia Due to Foraminal Stenosis.

Purpose Degenerative foraminal stenosis of the cervical spine can lead to cervicobrachial neuralgias. Computed tomography (CT)-scan assists in the diagnosis and evaluation of foraminal stenosis. The main objective of this study is to determine the bony dimensions of the cervical intervertebral foramen and to identify which foraminal measurements are most affected by degenerative disorders of the cervical spine. These data could be applied to the surgical treatment of this pathology, helping surgeons to focus on specific areas during decompression procedures. Methods A descriptive study was conducted between two groups: an asymptomatic one (young people with no evidence of degenerative cervical spine disorders) and a symptomatic one (experiencing cervicobrachial neuralgia due to degenerative foraminal stenosis). Using CT scans, we determined a method allowing measurements of the following foraminal dimensions: foraminal height (FH), foraminal length (FL), foraminal width in its lateral part ((UWPP, MWPP and IWPP (respectively Upper, Medial and Inferior Width of Pedicle Part)) and medial part (UWMP, MWMP and IWMP (respectively Upper, Medial and Inferior Width of Medial Part)), and disk height (DH). Foraminal volume (FV) was calculated considering the above data. Mean volumes were measured in the asymptomatic group and compared to the values obtained in the symptomatic group. Results Both groups were made up of 10 patients, and a total of 50 intervertebral discs (100 intervertebral foramina) were analyzed in each group. Comparison of C4C5, C5C6 and C6C7 levels between both groups showed several significant decreases in foraminal dimensions (p< 0,05) as well as in foraminal volume (p <0.001) in the symptomatic group. The most affected dimensions were UWPP, MWPP, UWMP, MWMP and FV. The most stenotic foraminal areas were the top of the uncus and the posterior edge of the lower plate of the overlying vertebra. Conclusion Using a new protocol for measuring foraminal volume, the present study refines the current knowledge of the normal and pathological anatomy of the lower cervical spine and allows us to understand the foraminal sites most affected by degenerative stenosis. Those findings can be applied to foraminal stenosis surgeries. According to our results, decompression of the foramen in regard of both uncus osteophytic spurs and inferior plate of the overlying vertebra might be an important step for nerve roots release.

Safety and Efficacy of Neuronavigation via Middle Frontal Gyrus Endoport-assisted Endoscopic Resection for Thalamic Lesions

BackgroundSurgery for thalamic lesions is generally challenging because they are deep-seated and surrounded by vital neurovascular structures. Whether neuronavigation via middle frontal gyrus endoport-assisted endoscopic resection for thalamic lesions is safe and effective remains to be further evaluated.Materials and MethodsTwelve patients treated surgically were retrospectively reviewed using the neuronavigation endoport-assisted endoscopy between January 2016 and April 2021 at Zhongshan Hospital of Fudan University. Preoperative and tumor-related variables, as well as postoperative outcomes, were also collected.ResultsAll lesions located in the medial part of the thalamus, and some of them expanded forward, downward, or backward. The median size of lesions was 29 mm (range 16-56 mm). The final pathology results showed 4 cases of benign lesions, 4 cases of low-grade glioma, and 4 cases of glioblastoma. All of the cases with benign lesions and low-grade glioma (100%) achieved GTR, while 3/4 (75%) of cases with glioblastoma achieved NTR, and 1 (25%) case obtained STR. None of the patients in this study have postoperative seizures. In the benign lesions and low-grade glioma group, worse Karnofsky performance status scores at discharge were 25%, and all achieved long-term postoperative survival. For patients with glioblastoma, 3/4 cases had worse Karnofsky performance status scores at discharge, and died within 6 months. ConclusionCombining the advantages of neuronavigation, endoscopy, and endoport techniques via the middle frontal gyrus approach can safely and effectively remove benign lesions and low-grade glioma in the medial part of the thalamus.

IDENTIFICATION OF A NOVEL BDNF-SPECIFIC CORTICOSTRIATAL CIRCUITRY

BDNF is released from axon terminals originating in the cerebral cortex onto striatal neurons. Here, we characterized BDNF in the corticostriatal circuitry. First, we utilized Bdnf-Cre and Ribotag transgenic mouse lines to label BDNF-positive cells in the cortex, and detected BDNF expression in the motor cortex, medial prefrontal cortex (mPFC) and the orbitofrontal cortex (OFC). Next, we used a retrograde viral tracing strategy, in combination with Bdnf-Cre knockin mice, to map the cortical outputs of BDNF neurons in the dorsal striatum. We found that the BDNF-positive prefrontal regions differentially project to the dorsal striatum. Specifically, BDNF-expressing neurons located in the mPFC project to both dorsolateral striatum (DLS) and dorsomedial striatum (DMS), and those located in the motor cortex project to the DLS. Surprisingly however, the BDNF-expressing OFC neurons differentially target the dorsal striatum depending on their mediolateral location. Specifically, the DMS is mainly innervated by the medial part of the OFC (mOFC) whereas, the DLS receives projections specifically from the ventrolateral region of the OFC (vlOFC). Next, using an anterograde viral tracing strategy, we confirmed the presence of a BDNF-specific vlOFC-DLS circuit. Finally, we show that overexpression of BDNF in the vlOFC activates TrkB signaling specifically in the DLS but not in the DMS demonstrating the functionality of this circuit. Our study uncovers a previously unknown neural circuit composed of BDNF-positive vlOFC neurons projecting to the DLS. These findings could have important implications for the role of BDNF signaling in the OFC as well as in other corticostriatal circuitries.

Endoscopic Two-Port Technique for Orbital Tumors, A Combined Transnasal and Sublabial Approach: A Retrospective Case Study

Background: We investigated the indications for a combined endoscopic transnasal and sublabial transantral approach for the surgical treatment of orbital lesions. Methods: This case study enrolled 10 patients scheduled for endoscopic transnasal surgery for treating orbital lesions from 2009 to 2020. When the tumor was localized to the medial part of the orbit, patients underwent endoscopy with a transnasal mononostril approach. Alternatively, when the tumor was localized to the mediocaudal part of the orbit, and when instrument maneuverability was limited, the transnasal approach was combined with a sublabial transantral approach. This two-port surgery approach was preferred over a trans-septal approach (binostril approach), because the two-port approach could expand the operating field in the medial part of the orbit. Here, we evaluated the indications, complications, and advantages of monoportal and combined two-portal approaches. Results: Among the 10 patients enrolled, 8 (80.0%) underwent surgery with the transnasal mononostril approach, and 2 (20.0%) underwent surgery with the combined transnasal mononostril and sublabial transantral approach. In the two latter cases, visualization of the operation field was excellent, and there was adequate room for manipulating instruments. No dysesthesia in the region of infraorbital nerve was observed postoperatively.Conclusion: The combination mononostril-transantral approach provided the space necessary to maneuver instruments and to visualize the surgical field in treating mediocaudal orbital lesions. This two-portal approach enabled extensive resections of intraconal lesions; thus, it could be considered a suitable alternative to the binostril approach.

Incidental T2 hyperintensities in the medial part of the bilateral globus pallidus are possibly an age-related physiological finding

Background and purpose Bilateral T2 hyperintensities in the medial part of the globus pallidus (GP) are sometimes incidentally observed in patients without a known history of diseases that present with such lesions. The purpose of this study was to evaluate the frequency of this finding and the association between this finding and age, lifestyle diseases and GP calcification. Methods We retrospectively investigated the brain magnetic resonance imaging (MRI) of 742 patients, which included between 104 and 108 consecutive patients from each decade of life between the 20s and 80s. The signal intensity ratio of the medial part to the lateral part of the GP in T2-weighted images (T2 medial/lateral ratio) was evaluated. For cases in which brain computed tomography images were available ( N=437), GP calcifications were also evaluated. The associations between the T2 medial/lateral ratio and age, sex, history of lifestyle diseases and GP calcification were investigated. Results Bilateral T2 medial/lateral ratios >1.10, 1.30 and 1.50 were observed in 29.8%, 7.1% and 1.8% of all cases, respectively. A high bilateral T2 medial/lateral ratio was observed less frequently in young patients ( p<0.01), more frequently in elderly patients and those with hypertension or dyslipidaemia ( p<0.05) and more frequently in patients with a calcified GP ( p<0.01). Conclusion Incidental bilateral T2 hyperintensities in the medial part of the GP on brain MRI are most likely an age-related physiological finding.

Medial Parabrachial Nucleus Is Essential in Controlling Wakefulness in Rats

Activation of the parabrachial nucleus (PB) in the brainstem induced wakefulness in rats, suggesting which is an important nucleus that controls arousal. However, the sub-regions of PB in regulating sleep-wake cycle is still unclear. Here, we employ chemogenetics and optogenetics strategies and find that activation of the medial part of PB (MPB), but not the lateral part, induces continuous wakefulness for 10 h without sleep rebound in neither sleep amount nor the power spectra. Optogenetic activation of glutamatergic MPB neurons in sleeping rats immediately wake rats mediated by the basal forebrain (BF) and lateral hypothalamus (LH), but not the ventral medial thalamus. Most importantly, chemogenetic inhibition of PB neurons decreases wakefulness for 10 h. Conclusively, these findings indicate that the glutamatergic MPB neurons are essential in controlling wakefulness, and that MPB-BF and MPB-LH pathways are the major neuronal circuits.

Botulinum Toxin A Injection for the Treatment of Intractable Dry Eye Disease

Background and Objectives: To evaluate the clinical efficacy of periocular botulinum toxin A (BTA) injection in patients with intractable dry eye disease (DED). Materials and Methods: Medical records of patients with intractable DED who underwent periocular BTA injection from December 2019 to March 2020 were reviewed retrospectively. Patients were injected with 2.5 units of BTA in the medial part of the lower eyelids. The clinical data collected included age, sex, ocular surface disease index (OSDI) score, tear film break up time (TBUT), Schirmer test results, tear osmolarity (I-PEN), and tear meniscus height (TMH) measured by anterior segment optical coherence tomography. All subjective and objective data were collected before treatment and at 1 month after treatment. Results: Twenty-eight consecutive patients were eligible for chart review and analysis. Significant improvements in OSDI, tear osmolarity, and TMH were observed at 1 month after periorbital BTA injection. At the baseline and 1-month follow-up examinations, OSDI scores were 62.22 ± 21.30 and 47.98 ± 17.23, respectively (p < 0.001). TMH increased significantly after treatment (82.25 ± 40.50 at baseline vs. 138.02 ± 66.62 1-month after treatment; p < 0.001). Tear osmolarity using I-PEN showed a significant decrease after treatment (320.82 ± 24.66 at baseline vs. 302.75 ± 22.33 at 1 month after treatment; p < 0.001). No significant differences were found in TBUT or Schirmer test results before and after BTA injection. Conclusions: BTA injection into the medial part of the eyelid improves dry eye symptoms, the amount of tear retention, and tear osmolarity. Based on the objective parameters of the tear condition, this study supports the idea of BTA use as a potential treatment option for patients with intractable DED.

Sternocleidohyoid muscle: an unreported variant of cleidohyoid muscle

Sternohyoid, sternothyroid, omohyoid, and thyrohyoid muscles are collectively known as infrahyoid muscles. These muscles frequently show variations in their attachments. Here, an extremely rare variant muscle belonging to this group has been presented. During cadaveric dissection for undergraduate medical students, an additional muscle was found between sternohyoid and superior belly of omohyoid muscles bilaterally in a male cadaver aged approximately 70 years. This muscle took its origin from posterior surface of the manubrium sterni, capsule of the sternoclavicular joint and the posterior surface of the medial part of the clavicle. It was inserted to the hyoid bone between the attachments of sternohyoid and superior belly of omohyoid muscles and was supplied by a branch of ansa cervicalis profunda. There is no report on such a muscle in the literature and it could be named as “sternocleidohyoid muscle”. Knowledge of this muscle could be useful in neck surgeries.