Citations

OBJECTIVE Sylvian fissure dissection following subarachnoid hemorrhage (SAH) is a challenging but fundamental skill in microneurosurgery, and one that has become increasingly difficult to develop during residency, given the overarching management trends. The authors describe a novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions. METHODS A standardized microvascular anastomosis model comprising rat femoral arteries and veins was used for the experimental framework. In the experimental protocol, following exposure and skeletonization of the vessels, extensive, superficial (1- to 2-mm) soft-tissue debridement was conducted and followed by wound closure and delayed reexploration at intervals of 7, 14, and 28 days. Two residents dissected 1 rat each per time point (n = 6 rats), completing vessel skeletonization followed by end-to-end artery/vein anastomoses. Videos were reviewed postprocedure to assess scar score and relative difficulty of dissection by blinded raters using 4-point Likert scales. RESULTS At all time points, vessels were markedly invested in friable scar, and exposure was subjectively assessed as a reasonable surrogate for sylvian fissure dissection under SAH conditions. Scar score and relative difficulty of dissection both indicated 14 days as the most challenging time point. CONCLUSIONS The authors’ experimental model of femoral vessel skeletonization, circumferential superficial soft-tissue injury, and delayed reexploration provides a novel approximation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions. The optimal reexploration interval appears to be 7–14 days. To the authors’ knowledge, this is the first model of SAH simulation for microsurgical training, particularly in a live animal system.

EXECUTIVE SUMMARY We recommend that ultrasound guidance should be used for paracentesis to reduce the risk of serious complications, the most common being bleeding. We recommend that ultrasound guidance should be used to avoid attempting paracentesis in patients with an insufficient volume of intraperitoneal free fluid to drain. We recommend that ultrasound guidance should be used with paracentesis to improve the success rates of the overall procedure. We recommend that ultrasound should be used to assess the volume and location of intraperitoneal free fluid to guide clinical decision making of where paracentesis can be safely performed. We recommend that ultrasound should be used to identify a needle insertion site based on size of the fluid collection, thickness of the abdominal wall, and proximity to abdominal organs. We recommend that the needle insertion site should be evaluated using color flow Doppler ultrasound to identify and avoid abdominal wall blood vessels along the anticipated needle trajectory. We recommend that a needle insertion site should be evaluated in multiple planes to ensure clearance from underlying abdominal organs and detect any abdominal wall blood vessels along the anticipated needle trajectory. We recommend that a needle insertion site should be marked with ultrasound immediately before performing the procedure, and the patient should remain in the same position between marking the site and performing the procedure. We recommend that using real‐time ultrasound guidance for paracentesis should be considered when the fluid collection is small or difficult to access. We recommend that dedicated training sessions, including didactics, supervised practice on patients, and simulation‐based practice, should be used to teach novices how to perform ultrasound‐guided paracentesis. We recommend that simulation‐based practice should be used, when available, to facilitate acquisition of the required knowledge and skills to perform ultrasound‐ guided paracentesis. We recommend that competence in performing ultrasound‐guided paracentesis should be demonstrated prior to independently performing the procedure on patients.

Many hospitalists incorporate point‐of‐care ultrasound (POCUS) into their daily practice to answer specific diagnostic questions or to guide performance of invasive bedside procedures. However, standards for hospitalists in POCUS training and assessment are not yet established. Most internal medicine residency training programs, the major pipeline for incoming hospitalists, have only recently begun to incorporate POCUS in their curricula. The purpose of this document is to inform a broad audience on what POCUS is and how hospitalists are using it. This document is intended to provide guidance for the hospitalists who use POCUS and administrators who oversee its use. We discuss POCUS 1) applications, 2) training, 3) assessments, and 4) program management. Practicing hospitalists must continue to collaborate with their local credentialing bodies to outline requirements for POCUS use. Hospitalists should be integrally involved in decision‐making processes surrounding POCUS program management.

AbstractIntroductionOur primary goal was to examine demographic and clinicopathologic differences across an ethnoracially diverse autopsy‐confirmed cohort of Alzheimer's disease cases.MethodsA retrospective study was conducted in the Florida Autopsied Multi‐Ethnic cohort on 1625 Alzheimer's disease cases, including decedents who self‐reported as Hispanic/Latino (n = 67), black/African American (n = 19), and white/European American (n = 1539).ResultsHispanic decedents had a higher frequency of family history of cognitive impairment (58%), an earlier age at onset (median age of 70 years), longer disease duration (median of 12 years), and lower MMSE proximal to death (median of 4 points) compared with the other ethnoracial groups. Black decedents had a lower Braak tangle stage (stage V) and higher frequency of coexisting hippocampal sclerosis (21%); however, only hippocampal sclerosis differences survived adjustment for sex, age at onset, and disease duration. Neither Thal amyloid phase nor coexisting Lewy body disease differed across ethnoracial groups.DiscussionDespite a smaller sample size, Hispanics demonstrated longer disease duration with Alzheimer's disease, but not greater lifespan. Neuropathologic differences across ethnoracial groups supported differences in tau pathology distribution and coexisting hippocampal sclerosis, which may impact biomarker studies.

Abstract Selected upper cerebellopontine angle (CPA)/petroclival region lesions can be visualized and resected through a middle fossa approach with anterior petrosectomy. This approach is particularly well suited for tumors that extend from the CPA into Meckel's cave or the middle cranial fossa. We present the case of a 55-yr-old man who presented with sudden left-sided hearing loss, with complete recovery after medical treatment. MRI demonstrated a left 1.8 cm contrast-enhancing upper CPA lesion with extension into Meckel's cave most consistent with a trigeminal schwannoma. The patient initially opted for observation. MRI 11 mo later showed notable enlargement in the tumor, and the patient started to experience left-sided neuralgic face pain. The decision was made to perform surgery. Documented and verified informed consent was obtained A step-by-step surgical video with surgical anatomy images highlights the 5 steps followed by the authors to perform an anterior petrosectomy. The dura mater was opened parallel to the superior petrosal sinus both in the infratentorial and supratentorial spaces in order to clip and coagulate the superior petrosal sinus and divide the tentorium. The lesion was fully visualized and the trigeminal nerve was clearly identified displaced inferiorly but not splayed by the tumor, making the diagnosis of trigeminal schwannoma unlikely. The lesion was debulked and dissected off the brainstem as well as the trigeminal nerve with the final view of intact nerve fascicles entering the posterior aspect of Meckel's cave. Pathology returned as a WHO grade 1 meningioma. The patient recovered well with only mild facial hypesthesia and complete tumor resection on follow-up imaging.

OBJECTIVEMiddle fossa surgery is challenging, and reliable surgical landmarks are essential to perform accurate and safe surgery. Although many descriptions of the middle fossa components have been published, a clinically practical description of this very complex anatomical region is lacking. Small structure arrangements in this area are often not well visualized or accurately demarcated with neuronavigation systems. The objective is to describe a “roadmap” of key surgical reference points and landmarks during middle fossa surgery to help the surgeon predict where critical structures will be located.METHODSThe authors studied 40 dry skulls (80 sides) obtained from the anatomical board at their institution. Measurements of anatomical structures in the middle fossa were made with a digital caliper and a protractor, taking as reference the middle point of the external auditory canal (MEAC). The results were statistically analyzed.RESULTSThe petrous part of the temporal bone was found at a mean of 16 mm anterior and 24 mm posterior to the MEAC. In 87% and 99% of the sides, the foramen ovale and foramen spinosum, respectively, were encountered deep to the zygomatic root. The posterior aspect of the greater superficial petrosal nerve (GSPN) groove was a mean of 6 mm anterior and 25 mm medial to the MEAC, nearly parallel to the petrous ridge. The main axis of the IAC projected to the root of the zygoma in all cases. The internal auditory canal (IAC) porus was found 5.5 mm lateral and 4.5 mm deep to the lateral aspect of the trigeminal impression along the petrous ridge (mean measurement values). A projection from this point to the middle aspect of the root of the zygoma, being posterior to the GSPN groove, could estimate the orientation of the IAC.CONCLUSIONSIn middle fossa approaches, the external acoustic canal is a reliable reference before skin incision, whereas the zygomatic root becomes important after the skin incision. Deep structures can be related to these 2 anatomical structures. An easy method to predict the location of the IAC in surgery is described. Careful study of the preoperative imaging is essential to adapt this knowledge to the individual anatomy of the patient.