OBJECTIVE: Postoperative bowel and bladder dysfunction (BBD) poses a significant risk following surgery of the sacral spinal segments and sacral nerve roots, particularly in neuro-oncology cases. The need for more reliable neuromonitoring techniques to enhance the safety of spine surgery is evident.
METHODS: We conducted a case series comprising 60 procedures involving 56 patients, spanning from September 2022 to January 2024. We assessed the diagnostic accuracy of sacral reflexes (bulbocavernosus and external urethral sphincter reflexes) and compared them with transcranial motor evoked potentials (TCMEP) incorporating anal sphincter (AS) and external urethral sphincter (EUS) recordings, as well as spontaneous electromyography (s-EMG) with AS and EUS recordings.
RESULTS: Sacral reflexes demonstrated a specificity of 100% in predicting postoperative BBD, with a sensitivity of 73.33%. While sensitivity slightly decreased to 64.71% at the 1-month follow-up, it remained consistently high overall. TCMEP with AS/EUS recordings did not identify any instances of postoperative BBD, whereas s-EMG with AS/EUS recordings showed a sensitivity of 14.29% and a specificity of 97.14%.
CONCLUSIONS: Sacral reflex monitoring emerges as a robust adjunct to routine neuromonitoring, offering surgeons valuable predictive insights to potentially mitigate the occurrence of postoperative BBD.

Neuro-monitoring is widely employed for the evaluation of intubated patients in the intensive care unit with stroke, severe head trauma, subarachnoid hemorrhage and/or hepatic encephalopathy. The present study reports the case of a patient with acute intracranial hemorrhage following the insertion of neuromonitoring catheters, which required surgical management. The patient was a 14-year-old male who sustained a severe traumatic brain injury and underwent a right-sided hemicraniectomy. During the installation of the neuromonitoring catheters, an acute hemorrhage was noted with a rapidly elevating intracranial pressure. A craniotomy was performed to identify and coagulate the injured cortical vessel. As demonstrated herein, the thorough evaluation of the clotting profile of the patient, a meticulous surgical technique and obtaining a post-insertion computed tomography scan may minimize the risk of any neuromonitoring-associated hemorrhagic complications.

Sellar xanthogranulomas are extremely rare intracranial lesions, particularly in pediatric patients, and their diagnostic and therapeutic challenges prompt thorough investigation. We describe a case of a two-year-old toddler diagnosed with sellar xanthogranuloma, highlighting the challenges encountered in its diagnosis and management. The child presented with symptoms, including headache, ptosis of the left eye, and neurological deficits. Brain computed tomography (CT) and magnetic resonance imaging (MRI) revealed a hypodense sellar lesion. The patient underwent a left pterional craniotomy for resection of the mass. Histopathological examination suggested the diagnosis of sellar xanthogranuloma, characterized by foamy macrophages, giant cells, lymphocytic infiltrates, fibrous proliferation, necrotic detritus, and hemosiderin deposits. Further diagnostic precision was achieved through immunohistochemical staining, including CD1a and langerin, which successfully ruled out the possibility of Langerhans cell histiocytosis (LCH), reinforcing the diagnosis of sellar xanthogranuloma. The successful surgical resection of the lesion led to a favorable outcome, evidenced by the significant alleviation of symptoms as well as the restoration of normal neurological function. Post-operative assessments demonstrated a marked improvement in the patient\'s quality of life, and there were no observed complications or recurrence of the lesion during the follow-up period. In summary, our case report not only highlights the rarity and diagnostic challenges of sellar xanthogranulomas but also emphasizes the importance of collaborative medical expertise in achieving accurate diagnosis and successful therapeutic outcomes in pediatric patients. The successful management of this case offers valuable insights into the clinical presentation, diagnostic complexities, and treatment strategy of sellar xanthogranulomas, further enriching our understanding of this uncommon intracranial pathology.

In the surgical treatment of cerebral vascular malformations, e.g., aneurysms and arteriovenous malformations, the risk of ischemic complications is 6.7%, and a residual aneurysm is possible in 5.2% of these cases. Ischemic lesions can result in permanent neurological deficits, and a residual aneurysm can lead to the recurrence of the aneurysm in 2% of cases. In this article, we present five cases (two cases of ruptured aneurysms, two cases of non-ruptured aneurysms, and a case of arteriovenous malformation) in which we reduced the aforementioned risks with the use of intraoperative neuromonitoring and angiography. Intraoperative neuromonitoring (IONM) is used to measure motor and sensory-evoked potentials to detect brain hypoperfusion. Intraoperative angiography with the dye indocyanine green (ICG-A), which fluoresces in a vessel under a microscope after intravenous administration, helps to identify residual aneurysm sacs and distal blood flow. With the use of IONM and ICG-A, we identified abnormalities and adjusted our interventions and treatments. IONM and ICG-A can lead to a better outcome after surgical treatment of cerebral vascular abnormalities.

Intraoperative neurophysiological monitoring (IONM) is a technique used to assess the somatosensory and gross motor systems during surgery. While it is primarily used to detect and prevent surgically induced nervous system trauma, it can also detect and prevent injury to the nervous system that is the result of other causes such as trauma or ischemia that occur outside of the operative field as a result of malpositioning or other problematic physiologic states. We present a case study where a neuromonitoring alert altered the surgical procedure, though the alert was not correlated to the site of surgery. A 69-year-old male with a history of bilateral moyamoya disease and a left middle cerebral artery infarct underwent a right-sided STA-MCA bypass and encephaloduroarteriosynangiosis (EDAS) with multimodal IONM. During the procedure, the patient experienced a loss of motor evoked potential (MEP) recordings in the right lower extremity. Blood pressure was elevated, which temporarily restored the potentials, but they were lost again after the angiography team attempted to place an arterial line in the right femoral artery. The operation was truncated out of concern for left hemispheric ischemia, and it was later discovered that the patient had an acute right external iliac artery occlusion caused by a fresh thrombus in the common femoral artery causing complete paralysis of the limb. This case highlights the importance of heeding IONM alerts and evaluating for systemic causes if the alert is not thought to be of surgical etiology. IONM can detect adverse systemic neurological sequelae that is not necessarily surgically induced.

Posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) are common modes of operative treatment of lumbar radiculopathy and spondylolisthesis. An integral part of these procedures is the appropriate placement of pedicle screws to ensure proper fusion. Breach of the medial cortex during pedicle screw fixation can potentially cause permanent impairment for a patient; significant technology and resources have been universally devoted to preventing this complication. Intraoperative neuromonitoring (IONM) is a frequently used tool by spine surgeons, which, along with fluoroscopy, is traditionally thought to reduce the incidence of neurologic injury. Unfortunately, IONM is not infallible and, in certain studies, has not been shown to decrease the risk of neurologic compromise. This case presentation details the clinical course of a 55-year-old who underwent an L4-5 TLIF. Despite benign electromyography recordings intraoperatively, the patient presented postoperatively with a new-onset left foot drop and a CT scan that confirmed bilateral L4 screw malposition with a breach of the medial cortex. We hope to further advance the discussion regarding the dangerous inconsistency of IONM in hopes of identifying a multimodal approach to avoid dreaded complications like this one in the future.

OBJECTIVE: Iatrogenic neurologic deficits adversely affect patient outcomes following brain tumor resection. Motor evoked potential (MEP) monitoring allows surgeons to assess the integrity of motor-eloquent areas in real-time during tumor resection to lessen the risk of iatrogenic insult. We retrospectively associate intraoperative transcranial and direct cortical MEPs (TC-MEPs, DC-MEPs) to early and late post-operative motor function to prognosticate short- and long-term motor recovery in brain tumor patients undergoing surgical resection in peri-eloquent regions.
METHODS: We reviewed 121 brain tumor patients undergoing craniotomies with DC-MEP and/or TC-MEP monitoring. Motor function scores were recorded at multiple time-points up to 1 year postoperatively. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were calculated at each time point.
RESULTS: The sensitivity, specificity, PPV, and NPV of TC-MEP in the immediate postoperative period was 17.5%, 100%, 100%, and 69.4%, respectively. For DC-MEP monitoring, the respective values were 25.0%, 100%, 100%, and 68.8%. By discharge, sensitivity had increased for both TC-MEP and DC MEPs to 43.8%, and 50.0% respectively. Subset analysis on patients without tumor recurrence/progression at long term follow-up (n = 62 pts, 51.2%) found that all patients with stable monitoring maintained or improved from preoperative status. One patient with transient intraoperative TC-MEP loss and permanent DC-MEP loss suffered a permanent deficit.
CONCLUSIONS: Brain tumor patients who undergo surgery with intact MEP monitoring and experience new postoperative deficits likely suffer transient deficits that will improve over the postoperative course in the absence of disease progression.

Hemangiopericytoma (HPC) of the trigeminal nerve is extremely rare. We present a case of a large cystic HPC of the mandibular division of the trigeminal nerve, only the third case described in the literature, with both intradural and extradural components. We describe the surgical approach, assisted by neurophysiological techniques of mapping and monitoring including blink reflex and triggered electromyography. Additionally, we report a method of monitoring of the sensory branches of the trigeminal nerve, poorly described in the literature, through peripheral and direct nerve stimulation and recording of transcranial somatosensory evoked potentials.

BACKGROUND: Spinal bronchogenic cysts are rare nonneoplastic congenital variants of neurenteric cysts. The natural history and surgical management of these lesions are poorly understood.
METHODS: A 25-year-old male presented with progressive back pain and bilateral lower limb sciatica of 6 months\' duration. He had undergone subtotal resection of an intramedullary bronchogenic conus medullaris cyst 5 years prior. Magnetic resonance imaging revealed a recurrent bilobed intramedullary and extramedullary conus medullaris cystic lesion. The authors resected the lesion via a posterior approach with the aid of intraoperative neuromonitoring. Gross total resection was precluded by the tightly adherent nature of the cyst and the fact that stimulation of a residual intramedullary portion of the lesion evoked external anal sphincter responses.
CONCLUSIONS: This is the first reported case of a bilobed intramedullary and extramedullary bronchogenic cyst of the conus medullaris. This unique case lends insight into the poorly defined embryogenesis of bronchogenic cysts by favoring the split notochord syndrome theory rather than the ectopic ectoderm proposal. The importance of neuromonitoring when resecting these tightly adherent lesions is demonstrated. Finally, although the secretory nature of these lesions portends a tendency for cyst reaccumulation, it is imperative to recognize that this is usually a slow process.

There are limited options for intravenous anesthetics and a lack of available information on the use of ketamine infusion during intracranial surgeries. We present a patient case report of hyperlactatemia during a craniotomy with neuromonitoring while on a propofol infusion with arterial lactate rising from 2.1 mmol/L to a peak of 5.0 mmol/L before reducing to 3.9 mmol/L after the transition to a mixed ketamine and dexmedetomidine infusion in order to maintain neuromonitoring quality and an appropriate depth of anesthesia. No complications were caused by the use of ketamine during this extended neurosurgery case.