Intraoperative Neurophysiological Monitoring in Neurosurgery.

Intraoperative neurophysiological monitoring (IONM) is a crucial advancement in neurosurgery, enhancing procedural safety and precision. This technique involves continuous real-time assessment of neurophysiological signals, aiding surgeons in timely interventions to protect neural structures. In addition to inherent limitations, IONM necessitates a detailed anesthetic plan for accurate signal recording. Given the growing importance of IONM in neurosurgery, we conducted a narrative review including the most relevant studies about the modalities and their application in different fields of neurosurgery. In particular, this review provides insights for all physicians and healthcare professionals unfamiliar with IONM, elucidating commonly used techniques in neurosurgery. In particular, it discusses the roles of IONM in various neurosurgical settings such as tumoral brain resection, neurovascular surgery, epilepsy surgery, spinal surgery, and peripheral nerve surgery. Furthermore, it offers an overview of the anesthesiologic strategies and limitations of techniques essential for the effective implementation of IONM.

An Unusual Asymptomatic Case of Unilateral Parotid Gland Agenesis.

Congenital absence of the major salivary glands, especially of the parotid gland, is a very infrequent condition of poorly understood etiology. This condition may be unilateral or bilateral and may occur alone or in association with the absence of other salivary glands or with other developmental craniofacial deformities of maxillofacial first and second branchial arch. Only 24 cases are documented in the literature. The authors present a case of a 79-year-old female who was referred to the Neurosurgery Department for neurocognitive impairment. The brain computed tomography with contrast enhancement incidentally showed a complete absence of the left parotid gland. The medical history and physical and radiographic examinations were indicative of nonsyndromic and nonfamilial asymptomatic unilateral aplasia of the parotid gland.

Primary Intracranial Gliosarcoma: Is It Really a Variant of Glioblastoma? An Update of the Clinical, Radiological, and Biomolecular Characteristics.

Gliosarcomas (GS) are sporadic malignant tumors classified as a Glioblastoma (GBM) variant with IDH-wild type phenotype. It appears as a well-circumscribed lesion with a biphasic, glial, and metaplastic mesenchymal component. The current knowledge about GS comes from the limited literature. Furthermore, recent studies describe peculiar characteristics of GS, such as hypothesizing that it could be a clinical-pathological entity different from GBM. Here, we review radiological, biomolecular, and clinical data to describe the peculiar characteristics of PGS, treatment options, and outcomes in light of the most recent literature. A comprehensive literature review of PubMed and Web of Science databases was conducted for articles written in English focused on gliosarcoma until 2023. We include relevant data from a few case series and only a single meta-analysis. Recent evidence describes peculiar characteristics of PGS, suggesting that it might be a specific clinical-pathological entity different from GBM. This review facilitates our understanding of this rare malignant brain tumor. However, in the future we recommend multi-center studies and large-scale metanalyses to clarify the biomolecular pathways of PGS to develop new specific therapeutic protocols, different from conventional GBM therapy in light of the new therapeutic opportunities.

Spinal Cord Stimulation in Chronic Low Back Pain Syndrome: Mechanisms of Modulation, Technical Features and Clinical Application.

Chronic low-back pain (CLBP) is a common disease with several negative consequences on the quality of life, work and activity ability and increased costs to the health-care system. When pharmacological, psychological, physical and occupational therapies or surgery fail to reduce CLBP, patients may be a candidate for Spinal Cord Stimulation (SCS). SCS consists of the transcutaneous or surgical implantation of different types of electrodes in the epidural space; electrodes are then connected to an Implanted Pulse Generator (IPG) that generates stimulating currents. Through spinal and supraspinal mechanisms based on the "gate control theory for pain transmission", SCS reduces symptoms of CLBP in the almost totality of well-selected patients and its effect lasts up to eight years in around 75% of patients. However, the evidence in favor of SCS still remains weak, mainly due to poor trial methodology and design. This narrative review is mainly addressed to those professionals that may encounter patients with CLBP failing conventional treatments. For this reason, we report the mechanisms of pain relief during SCS, the technical features and some clinical considerations about the application of SCS in patients with CLBP.

Deep brain stimulation for Parkinson's disease in practice: results of the survey by the Italian Neurosurgery Society.

BACKGROUND: Deep brain stimulation (DBS) is a safe and effective treatment for patients with advanced Parkinson's disease (PD) and many neurosurgical centers in Italy have a DBS program. Considering the prevalence of PD and criteria for DBS implantation, about 3200-10,350 PD patients may benefit from DBS in Italy. The global management of patients underwent DBS is complex and it can be supposed that many differences exist between centers in clinical practice. The Italian Neurosurgery Society (SINch) designed this survey to investigate the state of the art of DBS for PD in Italy. METHODS: A 26-item closed-ended question survey was designed and sanded by email at all Italian Neurosurgery centers. The main topic investigated was DBS teams, anatomical target selection, surgical procedure, neuroimaging, intraoperative target localization, DBS device and patients' follow-up. RESULTS: A total of 23 neurosurgery centers completed the survey. There are mainly low-to medium-volume centers (<20 annual DBS procedures) with dedicated DBS teams. The principal anatomical target used is subthalamic nucleus (STN) and, relative to the surgical technique, it emerges that in Italy DBS are bilaterally implanted in a single-step session with awake anesthesia and with frame-based technique. Final leads positioning is defined by microelectrode recordings (MER) and microstimulation (MS), with limited role of intraoperative neuroimaging (MRI and O-Arm). The stimulation is started at 15 or 30 days from procedure. CONCLUSIONS: Many centers of neurosurgery in Italy have a well-established DBS program for patients with advanced PD and some practical differences in technique between centers exist. Further investigation is needed to investigate specific criteria for selecting one technique over another.

Occipitocervical Fusion.

Occipitocervical fusion is a surgical technique in continuous evolution due to the innovation of devices, operative and instrumentation techniques. The aetiologies responsible for occipitocervical instability are trauma, neoplastic disease, metabolic disease or congenital disease. A variety of stabilization techniques are currently available depending on the type of patient and surgeon's experience. Each of these techniques requires thorough knowledge of the anatomy of the craniovertebral junction.

Cervical spinal cord compression from delayed epidural scar tissue formation around plate lead for SCS.

Cervical spinal compression is a serious and rare complication of spinal cord stimulation (SCS) that can occur using leads placed via open surgical approach. The present report describe a case of cervical plate lead implant that developed spinal and radicular compression symptoms after seven years due to the growth of fibrotic epidural mass at the level of lead. A review of literature is provided. A 59-year­old woman with 3-year history of left arm post­traumatic complex regional pain syndrome (CRPS) was treated with SCS performed with the implant of paddle lead in the epidural space from C3-C5. Seven years later she reported progressive paresthesia along the spine and the limbs, gait ataxia with sensation of weakness in the legs, increased muscle tone and tendon reflexes in the lower extremities and decrease in effectiveness of stimulation. Cervical CT showed a tissue mass into the cervical canal posteriorly to the lead. This finding was confirmed by MR performed after lead removal that also allowed to document the amount of spinal cord compression. The patient underwent C4-C5-C6 laminectomy and a thick scar was removed from the dura. After surgery there was progressive and incomplete improvement of neurological signs but symptoms related to algodystrophy recurred partly. The formation of hypertrophic epidural scar tissue at the level of lead implant must be taken into consideration in presence of the onset of progressive cervical myelopathy in patient treated with SCS using laminectomy lead.

A Novel Diagnostic and Prognostic Tool for Simple Decompression of Ulnar Nerve in Cubital Tunnel Syndrome.

BACKGROUND: Surgical decompression of the ulnar nerve (UN) is effective for treating cubital tunnel syndrome (CubTS). Nevertheless, the outcome is not always satisfying. Different surgical, clinical, and imaging findings have been claimed as outcome predictors, but there is no consensus in the literature. We analyzed the outcome-predicting role of ultrasonography (US) of the UN in patients with CubTS and its possible role for diagnosis and follow-up. METHODS: Patients with CubTS treated by simple UN decompression underwent US and electrodiagnotic (ED) studies of the UN at the elbow before and after surgery. Outcome was evaluated through the Bishop scale. A correlation analysis between pre- and postoperative clinical, US, and ED findings was performed. RESULTS: Thirty-six patients were enrolled. Preoperatively, we observed a negative correlation between the motor conduction velocity (MCV) and the transverse (TD) and anteroposterior diameters and cross-sectional area (CSA) of the UN at the precubital (P = 0.001, P = 0.001, P = 0.005) and cubital level (P = 0.02, P = 0.002, P = 0.001). Preoperative precubital TD and CSA were associated with outcome (P = 0.01, P = 0.006) and postoperative MCV (P = 0.004, P = 0.008). The cut-off values TD >6 mm and CSA >23.91 mm2 were predictors of poor outcome. Finally, postoperative cubital TD and CSA values were inversely correlated with outcome (P = 0.0002, P = 0.0007) and postoperative MCV (P = 0.0002, P = 0.0004). CONCLUSIONS: The US examination of the UN is useful for the management of patients with CubTS as an adjunct to clinical and ED evaluations. US measurements are correlated with pre- and postoperative ED findings and thus are useful for diagnosis and follow-up. Interestingly, specific precubital US measurements are good predictors of outcome.

An unusual association of headache, epilepsy, and late-onset Kleist's pseudodepression syndrome in frontal lobe cavernoma of the cerebral left hemisphere.

Cerebral cavernous angioma or cavernoma is a benign vascular malformation, usually asymptomatic. It is infrequent and often its discovery is incidental, a so-called incidentaloma. However, these lesions can be symptomatic, causing headaches, epilepsy, cerebral hemorrhage and other neurological signs depending on the brain area involved. Frontal localization is responsible for psychiatric disorders, particularly the prefrontal region, leading to prefrontal syndrome, a condition common in all frontal lobe tumors. Psychopathological syndrome can be depression-type, pseudodepression syndrome or maniac-type, pseudomaniac syndrome. Surgical treatment of lesions like this may not always be possible due to their location in eloquent areas. In this study, we describe an unusual association of migraine-like headache, epilepsy and frontal lobe pseudodepression late-onset syndrome in the same patient. We have considered this case interesting mainly for the rarity of both a headache with migraine features and for the late onset of pseudodepression syndrome. Pathophysiology underlying migraine-like headache and that concerning the late-onset pseudodepression frontal lobe syndrome seems to be unclear. This case leads to further hypotheses about the mechanisms responsible for headache syndromes and psychopathological disorders, in the specific case when caused by a cerebral frontal lobe lesion.