Clinical Instructor, Neurosurgery
Dr. Mandel obtained his medical degree from the University of São Paulo Medical School, Brazil. He received the “Prof. Dr. Edmundo Vasconcelos Award” as the best student on all surgical disciplines upon completion of medical school. He subsequently completed his neurosurgical residency at the Hospital das Clinicas of University of Sao Paulo Medical School, Brazil.
After his residency, Dr. Mauricio started a busy private practice at Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
His clinical and research interests are focused on minimally invasive neurosurgery. Dr. Mauricio attended a Ph.D. program at the University of Sao Paulo, Brazil, where he discussed a doctoral thesis entitled “Employment of minimally invasive neurosurgical techniques for treatment of unruptured brain aneurysms of the anterior circulation.” During his Ph.D. thesis, he described an innovative minimally invasive approach for the treatment of middle cerebral artery aneurysms (transpalpebral “eyelid” approach). He has published several peer-reviewed articles and has presented his work at different international conferences.
As Clinical Instructor at Stanford, Dr. Mauricio is currently concentrating on gaining operative exposure to cerebral revascularization procedures with Dr. Gary Steinberg.
Dr. Mandel, along with his wife Suzana, enjoys running, hiking and traveling. He also enjoys playing the cello. He has been a cellist in several university symphony orchestras in Sao Paulo.
OBJECTIVE: Craniocervical junction-related syringomyelia (CCJS) is the most common form of syringomyelia. Approximately 30% of patients treated with foramen magnum decompression (FMD) will show persistence, recurrence, or progression of the syrinx. The authors present a pilot study with a new minimally invasive surgery technique targeting the pathophysiology of CCJS in adult patients.METHODS: The authors retrospectively analyzed the clinical and radiological features of a consecutive series of patients treated for CCJS. An FMD and FM durectomy were performed through a 1.5- to 2-cm skin incision. Then arachnoid adhesions were cleared, creating a permanent communication from the fourth ventricle to the new paraspinal extradural cavity (obexostomy) and with the spinal subarachnoid space. The hypothesis was that the new CSF pouch acts like a pressure leak, interrupting the CCJS pathogenesis.RESULTS: Twenty-four patients (13 female, 21-61 years old) were treated between 2014 and 2018. The etiology of CCJS was Chiari malformation type I (CM-I) in 20 patients (83.3%), Chiari malformation type 0 (CM-0) in 2 patients (8.3%), and CCJ arachnoiditis in 2 patients (8.3%). Two patients underwent reoperations after failed FMD for CM-I at other institutions. No major surgical complication occurred. One patient had postoperative meningitis with no CSF fistula. On postoperative MRI, shrinkage of the syrinx was seen in all patients. No patients experienced recurrence of the CCJS. No patient required a subsequent operation. The mean duration of surgery was 72 ± 11 minutes (mean ± SD), and blood loss was 35-80 ml (mean 51 ml). Follow-up ranged from 12 to 58 months. The average overall improvement in modified Japanese Orthopaedic Association scores was 10% (p < 0.001). The Odom scale showed that 19 patients (79.1%) were satisfied, 4 (16.7%) remained the same, and 1 (4.2%) reported a poor outcome. All patients experienced postoperative improvement in perception of quality of life (p < 0.001).CONCLUSIONS: Minimally invasive FM durectomy and obexostomy is a safe and effective treatment for CCJS and for patients who have not responded to other treatment.
View details for DOI 10.3171/2020.2.SPINE2032
View details for PubMedID 32302978
Cavernous malformations of the midbrain require careful consideration of the risks and benefits of intervention, as well as optimal surgical approach for these challenging lesions. Excellent results can be achieved with careful surgical planning and technique.1,2 In this operative video, we demonstrate a contralateral left pterional craniotomy for trans-lamina terminalis approach to CO2 laser-assisted microsurgical resection of a thalamo-mesencephalic cavernoma in a 59 year old female presenting with progressive debilitating diplopia secondary to partial third nerve palsy. We utilized a contralateral left modified pterional craniotomy in which we limit dissection of the temporalis muscle to approximately one third rather than extending the muscle split down to the zygoma. The cavernous malformation was resected without complication and the patient was discharged from hospital on post-operative Day 3. She noted immediate improvement and nearly complete resolution of her symptoms over ensuing weeks. This approach offers a direct route to the lesion with minimal brain transgression while avoiding the critical structures within the interpeduncular cistern including basilar artery and thalamo-mesencephalic perforating arteries, as well as bordering neural structures including cerebral peduncles, oculomotor nerves and mamillary bodies. Use of the CO2 laser, with its 0.55mm tip, offers a low surgical profile and allows for precise cutting thus minimizing thermal damage to surrounding tissues. The trans-lamina terminalis approach, through a pterional craniotomy, offers a safe and potentially less morbid alternative to select thalamo-mesencephalic lesions compared to exposure through the mesencephalic surface which in our experience often necessitates an orbitozygomatic craniotomy.
View details for DOI 10.1016/j.wneu.2020.04.115
View details for PubMedID 32360676
Background: The anterior communicating artery complex may presente several anatomical variations, and many abnormalities have been reported in radiologiacal and cadaveric studies.Case Description: The authors present a case of a 44-year-old Caucasian female, with a prior history of smoking and arterial systemic hypertension, admitted in the emergency department complaining of a sudden headache, nausea, and vomiting followed by tonic-clonic seizures. Computerized tomography (CT) and angiography (angio- CT) were carried out and showed Fisher Grade IV subarachnoid hemorrhage. Angio-CT revealed an anterior communicating artery (AComA) aneurysm. Minimally invasive craniotomy and microsurgical clipping were performed uneventfully. An unusual anatomical variation of the AComA complex characterized by duplication of the AComA associated with a triplication of anterior cerebral artery (ACA) was observed. The patient was discharged with no neurological deficits.Concluision: This unique anatomical variation of the AComA-ACA complex constitute risck factors for development and rupture of aneurysms.
View details for DOI 10.25259/SNI_515_2019
View details for PubMedID 32257562
Cerebral vasospasm (CVS) following clipping of an unruptured aneurysm is a rare phenomenon. When it does occur, CVS usually occurs on the side ipsilateral to the surgical intervention.Here, we report the case of a 68-year-old male who underwent right-sided pterional craniotomy for clipping of an unruptured, anterior communicating artery aneurysm and experienced contralateral vasospasm five days later.We further discuss the pathophysiology underlying vasospasm after uncomplicated craniotomy and non-hemorrhagic aneurysm clipping.
View details for DOI 10.1016/j.wneu.2020.02.136
View details for PubMedID 32145422
Neurogenic neuroprotection is a promising approach for treating patients with ischemic brain lesions. In rats, stimulation of the deep brain nuclei has been shown to reduce the volume of focal infarction. In this context, protection of neural tissue can be a rapid intervention that has a relatively long-lasting effect, making fastigial nucleus stimulation (FNS) a potentially valuable method for clinical application. Although the mechanisms of neuroprotection induced by FNS remain partially unclear, important data have been presented in the last two decades. A 1-h electrical FNS reduced, by 59%, infarctions triggered by permanent occlusion of the middle cerebral artery in Fisher rats. The acute effect of electrical FNS is likely mediated by a prolonged opening of potassium channels, and the sustained effect appears to be linked to inhibition of the apoptotic cascade. A better understanding of the neuronal circuitry underlying neurogenic neuroprotection may contribute to improving neurological outcomes in ischemic brain insults.
View details for PubMedID 23597434
View details for PubMedCentralID PMC3861344
Background: We sought to evaluate the epidemiology of intracranial aneurysms in relation to location, gender, age, presence of multiple aneurysms, and comorbidities in the Brazilian population.Methods: We performed a prospective analysis of a cohort of 1404 patients diagnosed with intracranial aneurysm admitted to the Hospital das Clinicas of the University of Sao Paulo, a referral hospital for the treatment of cerebrovascular diseases in Brazil. Patients admitted between September 2009 and September 2018 with radiological diagnosis of intracranial aneurysm were included in the study.Results: A total of 2251 aneurysms were diagnosed. Females accounted for 1090 aneurysms (77.6%) and the mean age at diagnosis was 54.9 years (ranging 15-88). The most common location was middle cerebral artery (MCA) with 593 aneurysms (26.3%) followed by anterior cerebral artery (ACA) with 417 aneurysms (18.5%) and internal carotid artery in the posterior communicating segment with 405 aneurysms (18.0%). Males had higher rates of ACA aneurysms (29.7%) while females had higher rates of MCA aneurysms (26.1%). Sorting by size, 492 aneurysms were <5 mm (21.8%), 1524 measured 5-10 mm (67.7%), 119 size 11-24 mm (5.3%), and 116 were >24 mm (5.2%). The occurrence of multiple aneurysms was associated with female gender (P < 0.001) and smoking (P < 0.001), but not with hypertension (P = 0.121).Conclusion: In this population, the occurrence of intracranial aneurysm is related to several factors, including gender, age, smoking, and hypertension. Our study brought to light important characteristics of a large number of Brazilian patients regarding epidemiology, location, size, and multiplicity of intracranial aneurysms.
View details for DOI 10.25259/SNI_443_2019
View details for PubMedID 31893150
In BriefThe authors present a new surgical tool in which a smartphone is integrated with an endoscope by using a specially designed adapter, thus eliminating the need for a separate video system. This paper demonstrates that use of smartphones with endoscopes is a safe and efficient new method of performing endoscope-assisted neurosurgery, which also may increase surgeon mobility and reduce equipment costs.
View details for DOI 10.3171/2017.6.JNS1712
View details for PubMedID 29529913
Although anterior temporal lobectomy may be a definitive surgical treatment for epileptic patients with mesial temporal sclerosis, it often results in verbal, visual, and cognitive dysfunction. Studies have consistently reported the advantages of selective procedures compared with a standard anterior temporal lobectomy, mainly in terms of neuropsychological outcomes.To describe a new technique to perform a selective amygdalohippocampectomy (SAH) through a transpalpebral approach with endoscopic assistance.A mini fronto-orbitozygomatic craniotomy through an eyelid incision was performed in 8 patients. Both a microscope and neuroendoscope were used in the surgeries. An anterior SAH was performed in 5 patients who had the diagnosis of temporal lobe epilepsy with mesial temporal sclerosis. One patient had a mesial temporal lesion suggesting a ganglioglioma. Two patients presented mesial temporal cavernomas with seizures originating from the temporal lobe.The anterior approach allowed removal of the amygdala and hippocampus. The image-guided system and postoperative evaluation confirmed that the amygdala may be accessed and completely removed through this route. The hippocampus was partially resected. All patients have discontinued medication with no more epileptic seizures. The patients with cavernomas and ganglioglioma also had their lesions completely removed. One-year follow-up has shown no visible scars.The anterior route for SAH is a rational and direct approach to the mesial temporal lobe. Anterior SAH is a safe, less invasive procedure that provides early identification of critical vascular and neural structures in the basal cisterns. The transpalpebral approach provides a satisfactory cosmetic outcome.
View details for DOI 10.1227/NEU.0000000000001179
View details for PubMedID 28931250
Although recent technological advances have led to successful endovascular treatment, middle cerebral artery (MCA) aneurysms are still prone to surgery. Because minimally invasive options are limited and possess several functional and cosmetic drawbacks, a transpalpebral approach is proposed as a new alternative.To describe and assess surgical results of the minimally invasive transpalpebral approach in patients with MCA aneurysms.The data of 25 patients with unruptured MCA aneurysms from 2013 to 2016 were included in a cohort prospective database. We describe modifications of the approach and technique for MCA aneurysm clipping, in a step-by-step manner. The outcome was based on complications, procedural morbidity and mortality, and clinical and angiographic outcomes.All procedures were successfully performed in a standardized way, and no major complications related to the new approach were observed. Twenty-two patients were discharged the day after surgery (88%). The majority of aneurysms were 5 to 6 mm in diameter (mean, 7 mm; range 4-21 mm). All patients underwent postoperative angiographic control, which showed no significant residual neck. A 3-mo follow-up was sufficient to show no visible scars with excellent cosmetic results. The mean duration of follow-up was 16 mo.The transpalpebral approach comes as a minimally invasive, safe, definitive, and cosmetically adequate solution for MCA aneurysms at the present time.
View details for DOI 10.1093/ons/opx021
View details for PubMedID 28838124
The endoscopic technique has been described as a minimally invasive method for spontaneous hematoma evacuation, as a safe and effective treatment. Nevertheless, to our knowledge, there is no description of a technical report of traumatic intracerebral hematoma removal using the neuroendoscope. A 47-year-old man was admitted sustaining 13 points in Glasgow coma scale with brain computed tomography (CT) scan showing a temporal contusion. Guided by a 3D reconstructed CT, using the program OsiriX®, the posterior limit of the hematoma was identified. A burr hole was placed at the posterior temporal region, and we used the neuroendoscope to assist the hematoma evacuation. The postoperative tomography showed adequate hematoma removal. He was discharged from hospital 48 h after surgery. Two weeks later, he was conscious and oriented temporally. This endoscopic-assisted technique can provide safe removal of traumatic hematomas of the temporal lobe.
View details for DOI 10.1093/jscr/rjv132
View details for PubMedID 26537390
View details for PubMedCentralID PMC4631953
The evaluation of patients in the emergency room department (ER) through more accurate imaging methods such as computed tomography (CT) has revolutionized their assistance in the early 80s. However, despite technical improvements seen during the last decade, surgical planning in the ER has not followed the development of image acquisition methods. The authors present their experience with DICOM image processing as a navigation method in the ER. The authors present 18 patients treated in the Emergency Department of the Hospital das Clínicas of the University of Sao Paulo. All patients were submitted to volumetric CT. We present patients with epidural hematomas, acute/subacute subdural hematomas and contusional hematomas. Using a specific program to analyze images in DICOM format (OsiriX(®)), the authors performed the appropriate surgical planning. The use of 3D surgical planning made it possible to perform procedures more accurately and less invasively, enabling better postoperative outcomes. All sorts of neurosurgical emergency pathologies can be treated appropriately with no waste of time. The three-dimensional processing of images in the preoperative evaluation is easy and possible even within the emergency care. It should be used as a tool to reduce the surgical trauma and it may dispense methods of navigation in many cases.
View details for DOI 10.3390/s130506477
View details for PubMedID 23681091
View details for PubMedCentralID PMC3690066
Thalamotomies and pallidotomies were commonly performed before the deep brain stimulation (DBS) era. Although ablative procedures can lead to significant dystonia improvement, longer periods of analysis reveal disease progression and functional deterioration. Today, the same patients seek additional treatment possibilities.Four patients with generalized dystonia who previously had undergone bilateral pallidotomy came to our service seeking additional treatment because of dystonic symptom progression. Bilateral subthalamic nucleus DBS (B-STN-DBS) was the treatment of choice. The patients were evaluated with the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and the Unified Dystonia Rating Scale (UDRS) before and 2 years after surgery.All patients showed significant functional improvement, averaging 65.3% in BFMDRS (P = .014) and 69.2% in UDRS (P = .025).These results suggest that B-STN-DBS may be an interesting treatment option for generalized dystonia, even for patients who have already undergone bilateral pallidotomy.
View details for DOI 10.1002/mds.25127
View details for PubMedID 23038611
In the majority of cases, the correct treatment of brain lesions is possible only when the histopathological diagnosis is made. Several deep-seated lesions near eloquent areas are not safely approached by the classical neurosurgical procedures. These patients can get benefit by a minimally invasive procedure.We present a series of 176 consecutive patients submitted to stereotactic biopsies due to a great variety of brain lesions.Histological diagnosis found in this series: glioma in 40.1% of the patients, other neoplasms in 12.2% and infectious or inflammatory diseases in 29.1 %. The result was inconclusive in 5.2% of the procedures. One patient died (0.6%) and two (1.2%) presented operative complications. The criteria, advantages and risks of the stereotactic biopsies are discussed.The efficacy of the method is adequate and morbid-mortality rates were low.
View details for PubMedID 19330216
The purpose of this article was to assess if high-risk, mildly head-injured patients with normal CT scan present an outcome similar to the group with "low-risk MHI."A total of 379 hospital charts of inpatients with Glasgow Coma Scale scores of 13, 14, and 15 were reviewed. Information regarding age, fGCS, trauma mechanism, cranial CT scan findings, hospital course, and follow-up using the GOS were obtained from all patients.Patients were separated in 3 groups: fGCS 13 (46 patients), fGCS 14 (138 patients), and fGCS 15 (195 patients). The groups with different scores on fGCS did not differ regarding CT scan abnormalities, surgical treatment, or outcome. Patients were also separated in 2 groups based on CT scan findings: 266 patients had CT interpreted as abnormal and 113 had CT interpreted as normal. The 2 groups differed statistically regarding surgical treatment and scores on GOS (P < .05). There was no statistically significant difference between the 2 groups regarding sex, trauma mechanism, fGCS, or age.Our findings support the idea that a normal cranial CT scan in patients with fGCS scores of 13 or higher ascertain a low-risk MHI outcome and, therefore, such patients must be included in this category of traumatic brain injury. On the other hand, patients with cranial CT scan abnormalities should be included in the group with moderate head injury.
View details for DOI 10.1016/j.surneu.2005.11.034
View details for PubMedID 16427436
The authors present their experience in the management of posterior fossa epidural hematoma (PFEDH), which involved an aggressive diagnostic approach with the extensive use of head computerized tomography (CT) scanning.The authors treated 43 cases of PFEDH in one of the largest health centers in Brazil. Diagnosis was established in all patients with the aid of CT scanning because the clinical manifestations were frequently nonspecific. Cases were stratified by clinical course, Glasgow Coma Scale score, and their radiological status. Based on clinical and radiological parameters the patients underwent surgical or conservative management.Compared with outcomes reported in the available literature, good outcome was found in this series. This is primarily due to the broad use of CT scanning for diagnostic and observational purposes, which, in the authors' opinion, led to early diagnosis and prompt treatment.
View details for PubMedID 15209492
Neurogenic pulmonary edema (NPE) is an underdiagnosed clinical entity. Its pathophysiology is multifactorial but largely unknown. We report two cases of NPE and review the literature on NPE cases reported since 1990. A 21-year-old man had a seizure episode following cranioplasty. He became increasingly dyspneic, and clinical and laboratory signs of respiratory failure were evident. Chest radiography and computed tomography showed bilateral diffuse infiltrates. After supportive measures were taken, complete respiratory recovery occurred in 72 hours. A 52-year-old woman had several seizure episodes following subarachnoid hemorrhage due to a cavernoma. She became increasingly dyspneic upon arrival at the hospital. After tracheostomy and oxygen support were established, chest radiography showed bilateral diffuse infiltrates. Respiratory recovery was excellent, and the patient was eupneic with normal results of chest radiography 48 hours later. Fourteen reports (21 cases) were found. Thirteen patients were female, and the mean age of the patients was 31.6 years. The most frequent underlying factor was subarachnoid hemorrhage (42.9%). Symptom onset occurred <4 hours after the neurologic event in 71.4% of cases. One third of the patients presented with pink frothy sputum. Chest radiography showed bilateral diffuse infiltrates in 90.5% of cases. Supportive measures included oxygen support and vasoactive drugs. Recovery was usually very rapid: 52.4% of patients recovered in <72 hours. Almost 10% of patients died of NPE. Our two cases had clinical and laboratory features in common with most NPE cases. Physicians should remember NPE when neurologic patients suddenly become dyspneic. The mortality rate is high, but surviving patients usually recover very quickly.
View details for PubMedID 12658001
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