Prevention of trigeminocardiac reflex-induced severe bradycardia during cerebral aneurysm clipping surgery by topical anesthesia of the dura surface and atropine administration: a case report

Background Trigeminocardiac reflex (TCR) by stimulation of the sensory branch of the trigeminal nerve induces transient bradycardia and hypotension. We report a case in which light mechanical stimulation to the dura mater during brain surgery induced severe bradycardia. Case presentation A 77-year-old woman with bradycardia-tachycardia syndrome was scheduled for clipping of an unruptured left middle cerebral artery aneurysm. General anesthesia was performed with propofol, remifentanil, and rocuronium. Before starting surgery, the function of the pyramidal tract was examined by motor evoked potential. Transcranial electric stimulation for motor evoked potential induced atrial fibrillation and tachycardia. Continuous administration of landiolol was started and verapamil was used for tachycardia. During detachment of the dura mater from the bone, an electrocardiogram suddenly showed sinus arrest for 6 s. Immediately after the manipulation was interrupted, a junctional rhythm appeared. However, light touch to the dura mater induced severe bradycardia again, and atropine was therefore administered. In addition, the dura surface was anesthetized with topical lidocaine infiltration. After that, light touch-induced bradycardia was prevented. Conclusions We experienced a case of severe bradycardia during surgery due to TCR caused by light mechanical stimulation to the dura mater. Topical anesthesia of the dura surface and atropine administration were effective for preventing TCR-induced bradycardia.

Surgical strategy for tuberculous brain abscess with dural infiltration: A case report

Background: Tuberculosis is one of the top 10 leading causes of death worldwide. Although tuberculous central complications account for 1% of all tuberculosis patients, there are many cases of medical resistance; and early surgical treatment is required for brain abscess. Reports on tuberculous brain abscesses with dural infiltration are rare, and there are no reports on surgical treatment methods. Case Description: An 81-year-old man was presented with the right arm paresis. His recent medical history included a 6-month course of immunosuppressants, and steroids prescribed for ulcerative colitis, and four antituberculosis drugs had been started 2 months before for relapse of pulmonary tuberculosis at an early age. Head T1-weighted magnetic resonance imaging with administration of gadolinium showed two ring-enhanced lesions in the left precentral gyrus and continuous with the dura mater. Surgery was performed and he was pathologically diagnosed with a tuberculous brain abscess. Since the pathological diagnosis revealed dura mater invasion, we removed the dura mater and reconstructed by periosteum. After the surgery, the symptoms gradually improved, and the abscess and edema improved when viewed on the image. Despite the administration of steroids for ulcerative colitis without antituberculosis drugs, no recurrence was observed for 1 year. Recurrence of tuberculous brain abscess is a major problem in immunosuppressed patients, but it is considered that the relapse could be prevented by removing the dural infiltration. Conclusion: In cases of tuberculous brain abscess with dural infiltration, it is considered that the recurrence can be prevented even in an immunosuppressed state by removing the dura.

Comparison of Absolute Dose Achievable Between Helical Tomotherapy and RapidArc in Total Dura Mater Irradiation for Child Cancer

Background and Purpose: In this study, the absolute dose achievable between helical tomotherapy (HT) plans and RapidArc (RA) plans for total dura mater irradiation (TDMI) was compared. Materials and methods: A planning study was conducted on nine children's case datasets with dura mater metastasis of neuroblastoma. The target included the entire calvarium and skull base and formed a closed volume with a certain thickness around the brain. HT and RA plans with four coplanar full arcs (RA4) with half-field technique were generated for the comparison of absolute dose achievable. In total, 30.6 Gy was prescribed as D95% (ie, dose to 95% of PTV volume). Results: In the dosimetric comparison between the two modalities, HT provided more homogenous dose distribution than RA4 (mean HI5−95%: 1.046 vs 1.088, P < .001). The V107% and D2Gy of PTV in HT versus RA4 were 3.06% versus 30.47% and 32.59 Gy versus 33.45 Gy, respectively. HT reduced the Dmean and V5Gy of the brain, brainstem, and hippocampus by 25%–48% and 27%–56% compared with RA4, respectively. Conclusion: Both techniques could provide sufficient coverage for targets, but HT offered more homogenous dose to PTV and lower dose to the central region of the brain involving the brainstem and hippocampus. RA4 could be completed in a shorter time with lower MUs, but with relatively higher dose to the brain or hippocampus. In terms of dosimetry, HT may improve long-term cognitive decline in these young pediatric patients with TDMI.

Effect of Anatomical Sites On the Mechanical Properties of Spinal Dura Subjected to Biaxial Stretching

The spinal cord is encased by spinal meninges called the pia, arachnoid, and dura maters. Among these membranes, the dura mater is the thick and outermost layer and is the toughest and strongest. Thus, mechanical failure of the dura mater can lead to spontaneous cerebrospinal fluid leaks or hypovolemia, resulting in a complication or exacerbation of unfavorable symptoms involved in a mild traumatic brain injury. To develop protective equipment that can help prevent such injuries, accurate characterization of the spinal dura mater is required, especially regarding the mechanical properties at different anatomical sites. In this study, we used an equiload biaxial tensile tester to investigate the mechanical properties of porcine meningeal dura mater along the whole length of the spine. The resultant strain of the dorsal side was greater than that of the ventral side (P &lt; 0.01), while the circumferential direction was significantly stiffer than the longitudinal direction (P &lt; 0.01) at lower strains regardless of the spinal level. We also found that the material stiffness progressively increased from the cervical level to the thoracolumbar level at lower strains, which implies that the dura mater inherently possesses structurally preferred features or functions because the neck requires sufficient flexibility for daily activities. Further, Young's modulus was significantly less on the dorsal side than on the ventral side at higher strains (P &lt; 0.05), suggesting that the dorsal side is readily elongated by spinal flexion even within the range of physiological motion.

B-Mode Ultrasound, a Reliable Tool for Monitoring Experimental Intracerebral Hemorrhage

Background: Magnetic resonance imaging (MRI) is currently used for the study of intracerebral hemorrhage (ICH) in animal models. However, ultrasound is an inexpensive, non-invasive and rapid technique that could facilitate the diagnosis and follow-up of ICH. This study aimed to evaluate the feasibility and reliability of B-mode ultrasound as an alternative tool for in vivo monitoring of ICH volume and brain structure displacement in an animal model.Methods: A total of 31 male and female Sprague-Dawley rats were subjected to an ICH model using collagenase-IV in the striatum following stereotaxic references. The animals were randomly allocated into 3 groups: healthy (n = 10), sham (n = 10) and ICH (n = 11). B-mode ultrasound studies with a 13-MHz probe were performed pre-ICH and at 5 h, 48 h, 4 d and 1 mo post-ICH for the assessment of ICH volume and displacement of brain structures, considering the distance between the subarachnoid cisterns and the dura mater. The same variables were studied by MRI at 48 h and 1 mo post-ICH.Results: Both imaging techniques showed excellent correlation in measuring ICH volume at 48 h (r = 0.905) and good at 1 mo (r = 0.656). An excellent correlation was also observed in the measured distance between the subarachnoid cisterns and the dura mater at 1 mo between B-mode ultrasound and MRI, on both the ipsilateral (r = 0.870) and contralateral (r = 0.906) sides of the lesion.Conclusion: B-mode ultrasound imaging appears to be a reliable tool for in vivo assessment of ICH volume and displacement of brain structures in animal models.

Histopathological Investigation of Dura-Like Membrane in Vestibular Schwannomas

The dura-like membrane (DLM) is an outermost membranous structure arising from the dura mater adjacent to the internal auditory meatus (IAM) that envelops some vestibular schwannomas (VSs). Its recognition is important for the preservation of the facial and cochlear nerves during tumor resection. This study analyzes the histopathological characteristics of the DLM. The expression of CD34 and αSMA was histopathologically analyzed in tumor and DLM tissue of 10 primary VSs with and without a DLM. Tumor volume, resection volume percentage, microvessel density (MVD), and vessel diameter were analyzed. Volumetric analysis revealed that the presence of a DLM was significantly associated with lower tumor resection volume (p < 0.05). Intratumoral vessel diameter was significantly larger in the DLM group than the non-DLM group (p < 0.01). Larger VSs showed a higher intratumoral MVD in the DLM group (p < 0.05). Multilayered αSMA-positive vessels were identified in the DLM, tumor, and border; there tended to be more of these vessels within the tumor in the DLM group compared to the non-DLM group (p = 0.08). These arteriogenic characteristics suggest that the DLM is formed as the tumor induces feeding vessels from the dura mater around the IAM.

A rare case: Penetrating craneoencefalic trauma by knife

Background: Cranioencephalic penetrating trauma (CPT) is caused by a sharp or short- pointed object that passes through the bone, dura mater, brain and other structures. Its incidence is unknown and few cases are described; penetrating injuries represent 0.4%, therefore there is no protocolized management. Case report: A 24-year-old male patient suffered penetrating trauma at left parietal region with a "knife"; he was sutured and sent home with analgesics. Five days after the trauma, he was admitted for headache, disorientation and decreased visual acuity. X-ray (XR) of Cranium evidencing a foreign body, therefore it is sent to a reference hospital. Evolution: The diagnosis is confirmed by a computerized tomography (CT) scan of the skull with 3-dimensional reconstruction (3D) plus CT angiography (angio CT), which shows "knife" in the left parietal region without vascular compromise. Neurosurgeons perform removal of the foreign body plus a dura mater plasty. Patient stay 12 days hospitalized with a favorable evolution and improvement of neurological symptomatology. Conclusion: CPT due to a knife is an emergency and there is no protocolized management. The removal of the foreign body must be done in a hospital for the risk of lesions of large vessels.