A novel method of neurophysiological brainstem mapping in neurosurgery.

BACKGROUND: Brainstem mapping with electrical stimulation allows functional identification of neural structures during resection of deep lesions. Single pulses or train of pulses are delivered to map cranial nerves and corticospinal tracts, respectively. NEW METHOD: We introduce a hybrid stimulation technique for mapping the brainstem. The stimulus consists of an electrical single pulse followed by a short train of 3-5 pulses at 500 Hz, at an interval of 60-75 ms. The responses to this stimulation pattern are recorded from appropriate cranial and limb muscles. RESULTS: Both the single pulse and the short train elicit electromyographic responses when motor fibers or motor nuclei of the cranial nerves are stimulated. Responses to the train but not to the preceding single pulse indicate activation of the descending motor tracts, in the mesencephalon and the pons. Conversely, in the medulla, limb responses to stimulation of the corticospinal tracts are elicited by a single pulse. Identification of the extra and intra-axial courses of the trigeminal motor and sensory fibers is possible by recording responses from the masseter and the tongue muscles. COMPARISON WITH EXISTING METHOD(S): To date, either a pulse or a train is delivered during brainstem mapping, switching from one to the other modality according to the expected target structure. This procedure can be time-consuming and may even lead to false negative responses to the stimulation, eventually leading to inaccurate neurosurgical procedures. CONCLUSIONS: The novel hybrid pulse-train technique enhances the advantage of brainstem mapping procedure, minimizing pitfalls and improving patient safety.

Spinal epidural abscess in COVID-19 patients.

OBJECTIVE: To report the peculiarity of spinal epidural abscess in COVID-19 patients, as we have observed an unusually high number of these patients following the outbreak of SARS-Corona Virus-2. METHODS: We reviewed the clinical documentation of six consecutive COVID-19 patients with primary spinal epidural abscess that we surgically managed over a 2-month period. These cases were analyzed for what concerns both the viral infection and the spinal abscess. RESULTS: The abscesses were primary in all cases indicating that no evident infective source was found. A primary abscess represents the rarest form of spinal epidural abscess, which is usually secondary to invasive procedures or spread from adjacent infective sites, such as spondylodiscitis, generally occurring in patients with diabetes, obesity, cancer, or other chronic diseases. In all cases, there was mild lymphopenia but the spinal abscess occurred regardless of the severity of the viral disease, immunologic state, or presence of bacteremia. Obesity was the only risk factor and was reported in two patients. All patients but one were hypertensive. The preferred localizations were cervical and thoracic, whereas classic abscess generally occur at the lumbar level. No patient had a history of pyogenic infection, even though previous asymptomatic bacterial contaminations were reported in three cases. CONCLUSION: We wonder about the concentration of this uncommon disease in such a short period. To our knowledge, cases of spinal epidural abscess in COVID-19 patients have not been reported to date. We hypothesize that, in our patients, the spinal infection could have depended on the coexistence of an initially asymptomatic bacterial contamination. The well-known COVID-19-related endotheliitis might have created the conditions for retrograde bacterial invasion to the correspondent spinal epidural space. Furthermore, spinal epidural abscess carries a significantly high morbidity and mortality. It is difficult to diagnose, especially in compromised COVID-19 patients but should be kept in mind as early diagnosis and treatment are crucial.

Holmes tremor: a delayed complication after resection of brainstem cavernomas.

OBJECTIVE: In this paper, the authors aimed to illustrate how Holmes tremor (HT) can occur as a delayed complication after brainstem cavernoma resection despite strict adherence to the safe entry zones (SEZs). METHODS: After operating on 2 patients with brainstem cavernoma at the Great Metropolitan Hospital Niguarda in Milan and noticing a similar pathological pattern postoperatively, the authors asked 10 different neurosurgery centers around the world to identify similar cases, and a total of 20 were gathered from among 1274 cases of brainstem cavernomas. They evaluated the tremor, cavernoma location, surgical approach, and SEZ for every case. For the 2 cases at their center, they also performed electromyographic and accelerometric recordings of the tremor and evaluated the post-operative tractographic representation of the neuronal pathways involved in the tremorigenesis. After gathering data on all 1274 brainstem cavernomas, they performed a statistical analysis to determine if the location of the cavernoma is a potential predicting factor for the onset of HT. RESULTS: From the analysis of all 20 cases with HT, it emerged that this highly debilitating tremor can occur as a delayed complication in patients whose postoperative clinical course has been excellent and in whom surgical access has strictly adhered to the SEZs. Three of the patients were subsequently effectively treated with deep brain stimulation (DBS), which resulted in complete or almost complete tremor regression. From the statistical analysis of all 1274 brainstem cavernomas, it was determined that a cavernoma location in the midbrain was significantly associated with the onset of HT (p < 0.0005). CONCLUSIONS: Despite strict adherence to SEZs, the use of intraoperative neurophysiological monitoring, and the immediate success of a resective surgery, HT, a severe neurological disorder, can occur as a delayed complication after resection of brainstem cavernomas. A cavernoma location in the midbrain is a significant predictive factor for the onset of HT. Further anatomical and neurophysiological studies will be necessary to find clues to prevent this complication.

Arachnoid cyst in young soccer players complicated by chronic subdural hematoma: personal experience and review of the literature.

Arachnoid cysts (ACs) are congenital intracranial benign cavities originating from the meninges during embryological development. Several studies have shown the existence of a relationship between AC and a higher risk to develop ipsilateral chronic subdural hematoma (CSH) especially in a young population. In the presence of an AC, the practice of sport activities may expose young patients to minor head trauma and to an increased risk of developing CSH. We describe three cases of young soccer players with AC associated with CSH. Then, we performed a literature review of all the reported cases in the literature of patients younger than 18 years with AC-associated CSH related to sport practice. A total of 33 cases, including the three cases reported by us, are analyzed. Soccer is the most represented sport activity in this association (39% of cases). The treatment of choice is surgical in all patients, with burr hole or craniotomy in similar proportions. In one-third of patients, the AC has been fenestrated. Outcome is good in all the reported cases. We reviewed the main pathogenic theories, the main surgical strategies described in literature, as well as recurrence rate of CSH, the association of AC and cranial deformities, and the clinical outcome. AC might be associated with skull deformities, but their real incidence remains unclear. The clinical detection of such anomalies should suggest performing further radiological investigations. If the presence of AC is confirmed, the practice of sport activities should not be avoided, as the real incidence of AC-associated CSH is not clear yet and the reported outcomes in literature are good. Surgical treatment of AC-associated CSH should be hematoma removal through burr hole, reserving AC fenestration only for cases with intracystic bleeding or recurrences. The surgeon should adequately advise and inform the young patients and their families that they could have an increased risk of developing CSH given by the presence of the AC, and that they should be referred to a neurosurgical center if they become symptomatic.

Hydrocephalus due to a Cavernoma-Like Lesion of an Obliterated Cerebral Arteriovenous Malformation Treated by Embolization and Radiosurgery.

BACKGROUND: Gamma-Knife radiosurgery can be the treatment of choice for small cerebral arteriovenous malformations (AVMs) in eloquent brain areas or, in association with endovascular treatment, for large and complex AVMs. Among the possible delayed complications occurring after radiosurgery of AVMs, de novo formation of a cavernoma has only recently been described. The authors report a unique case of communicating hydrocephalus with highly proteinaceous cerebrospinal fluid due to a cavernoma-like lesion of an obliterated cerebral AVM treated by embolization and radiosurgery. CASE DESCRIPTION: A 43-year-old female patient with a left parieto-occipital AVM (Spetzler-Martin grade III) underwent a multimodality treatment comprising several endovascular procedures and Gamma-Knife radiosurgery. At the follow-up angiograms, the AVM was completely obliterated. Twelve years later, she came back to our attention for headache and vomit with the radiological evidence of brain edema, severe hydrocephalus, and a chronic encapsulated intracerebral hematoma. At the beginning, the drainage of hydrocephalus proved ineffective to improve symptoms and edema. Therefore, the surgical resection of both the obliterated AVM and the cavernoma-like lesion-histologically confirmed-was necessary. The hydrocephalus resolved as well as the cerebral edema after 3 weeks, without necessity of a ventriculoperitoneal shunt. CONCLUSIONS: In previous neurosurgical literature, the association of a caveroma-like lesion in an obliterated AVM and communicating hydrocephalus with highly proteinaceous cerebrospinal fluid has not yet been discussed. We believe that only the surgical resection of both the obliterated AVM and the cavernoma-like lesion can lead to complete clinical recovery of the hydrocephalus.

Immunological diagnosis as an adjunctive tool for an early diagnosis of tuberculous meningitis of an immune competent child in a low tuberculosis endemic country: a case report.

BACKGROUND: Pediatric tuberculous meningitis is a highly morbid, often fatal disease. Its prompt diagnosis and treatment saves lives, in fact delays in the initiation of therapy have been associated with high mortality rates. CASE PRESENTATION: This is a case of an Italian child who was diagnosed with tuberculous meningitis after a history of a month of headache, fatigue and weight loss. Cerebrospinal fluid analysis revealed a lymphocytic pleocytosis with predominance and decreased glucose concentration. Microscopy and conventional diagnostic tests to identify Mycobacterium tuberculosis were negative, while a non classical method based on intracellular cytokine flow cytometry response of CD4 cells in cerebral spinal fluid helped us to address the diagnosis, that was subsequently confirmed by a nested polymerase chain reaction amplifying a 123 base pair fragment of the M. tuberculosis DNA. CONCLUSIONS: We diagnosed tuberculous meningitis at an early stage through an innovative immunological approach, supported by a nested polymerase chain reaction for detection of M. tuberculosis DNA. An early diagnosis is required in order to promptly initiate a therapy and to increase the patient's survival.

Calcified Spinal Meningiomas.

OBJECTIVE: To analyze outcomes of patients surgically treated for calcified spinal meningiomas and to determine factors associated with surgical morbidity. METHODS: Between January 2000 and June 2013, a total of 54 patients underwent surgical resection of a spinal meningioma: 37 of these cases showed various degrees of calcification, confirmed by histopathologic analysis. The clinical evaluation was performed according to the American Spinal Injury Association Impairment Scale. At the last follow-up, neurologic status improved in 19 cases and remained unchanged in 20 cases; just 1 case worsened. According to the American Spinal Injury Association Impairment Scale, neurologic status was classified into 3 levels: poor (A + B), fair (C), and good (D + E). Neurologic status improvement (NSI) during postoperative time (considered as a transition from one lower level to the higher) was analyzed in relationship to the patient's age, length of clinical history, spine level, meningioma's position inside the spinal canal, and its degree of calcification. RESULTS: A statistically significant relationship between NSI and the degree of ossification of the meningioma was observed. in particular, a direct relationship with microcalcified meningiomas and an inverse relationship with ossified meningiomas. No relationship was observed between NSI and patient's age, length of clinical history, and the site of the lesion into the vertebral canal. CONCLUSIONS: The univariate analysis confirms that the degree of calcification affects the outcome, because extensive tumor calcification is associated with an increased surgical morbidity probably.

First description of cervical intradural thymoma metastasis.

Thymoma and thymic carcinoma are rare epithelial tumors, which originate from the thymus gland. According to the World Health Organization there are "organotypic" (types A, AB, B1, B2, and B3) and "non-organotypic" (thymic carcinomas) thymomas. Type B3 thymomas are aggressive tumors, which can metastasize. Due to the rarity of these lesions, only 7 cases of extradural metastasis are described in the literature. We report the first and unique case of a man with cervical intradural B3 thymoma metastasis. A 46-year-old man underwent thymoma surgical removal. The year after the procedure he was treated for a parietal pleura metastasis. In 2006 he underwent cervical-dorsal extradural metastasis removal and C5-Th1 stabilization. Seven years after he came to our observation complaining left cervicobrachialgia and a reduction of strength of the left arm. He underwent a cervical spine magnetic resonance imaging, which showed a new lesion at the C5-C7 level. The patient underwent a surgery for the intradural B3 thymoma metastasis. Neurological symptoms improved although the removal was subtotal. He went through postoperative radiation therapy with further mass reduction. Spinal metastases are extremely rare. To date, only 7 cases of spinal extradural metastasis have been described in the literature. This is the first case of spinal intradural metastasis. Early individuation of these tumors and surgical treatment improve neurological outcome in patients with spinal cord compression. A multimodal treatment including neoadjuvant chemotherapy, surgery and postoperative radiation therapy seems to improve survival in patients with metastatic thymoma.

Cervical congenital spondylolytic spondylolisthesis associated with duplication of the vertebral artery: case report.

BACKGROUND CONTEXT: Cervical bilateral congenital spondylolysis with spondylolisthesis is an abnormality both of congenital and mechanical origin, characterized by its primary feature, cervical bilateral spondylolysis. We are unaware of any reports describing cervical congenital spondylolytic spondylolisthesis associated with duplication of the vertebral artery. PURPOSE: To report the case of a patient affected with cervical bilateral congenital spondylolysis with spondylolisthesis associated with duplication of the vertebral artery. STUDY DESIGN: A unique case report from a university hospital and a literature review. PATIENT SAMPLE: An 18-year-old man who arrived at the emergency department complaining of neck pain starting from a car accident 5 days ago. METHODS: Neurologic examination and images taken by ordinary radiographs, magnetic resonance imaging (MRI) scans, ordinary computed tomography (CT) scans, and CT angiograms with three-dimensional (3D) reconstruction. RESULTS: Neurologic examination did not find evidence of strength deficit in upper extremities. Ordinary radiographs of the cervical spine showed spondylolisthesis of C6 and C7 and a cortical cleft between the superior and inferior articular facets of the C6 vertebra and spina bifida of the C6 and C2 vertebrae and an abnormal appearance of the remnant spinous processes of the cervical vertebrae. Magnetic resonance imaging confirmed the abnormalities that had been noted on the radiographs. Computed tomography scans of the cervical spine showed congenital spondylolytic spondylolisthesis and spina bifida of the C6 vertebra and duplication of the vertebral artery. They also showed double origins of the vertebral artery depicted by 3D angiographic reconstruction. Conservative treatment of wearing a cervical collar and receiving muscle relaxants and anti-inflammatory drugs was effective. With the pain completely subsided, the patient was discharged 5 days after arriving at the emergency department. CONCLUSIONS: Vascular abnormalities should be suspected and investigated in cases of congenital spondylolysis or spondylolytic spondylolisthesis. We strongly suggest performing angio-CT or angio-MRI and 3D reconstruction in these cases. Awareness of the presence of a duplicated vertebral artery and the course of its limbs could significantly help planning in cases proceeding to surgery.

Twelfth nerve paresis induced by an unusual posterior fossa arachnoid cyst: case report and literature review.

There are only three cases of arachnoid cysts inducing twelfth nerve paresis described in English medical literature. We herein report one more instance. Six weeks after surgery, the patient has almost fully recovered. This case underlines the importance of considering the arachnoid cyst as a possible cause of twelfth nerve paresis.