Dynamic Workflow Proposal for Continuous Frameless Electromagnetic Neuronavigation in Rigid Neuroendoscopy.

BACKGROUND: Ventriculoscopic neuronavigation has been described in several articles. However, there are different ventriculoscopes and navigation systems. Due to these different combinations, it is difficult to find detailed neuronavigation protocols. We describe, step-by-step, a simple method to navigate both the trajectory until reaching the ventricular system, as well as the intraventricular work. METHODS: We use a rigid ventriculoscope (LOTTA, KarlStorz) with an electromagnetic stylet (S8-StealthSystem, Medtronic). The protocol is based on a modified or 3-dimensionally printed trocar for navigating the extraventricular step and on a modified pediatric nasogastric tube for the intraventricular navigation. RESULTS: This protocol can be set up in less than 10 minutes. The extraventricular part is navigated by introducing the electromagnetic stylet inside the modified or 3-dimensionally printed trocar. Intraventricular navigation is done by combining a modified pediatric nasogastric tube with the electromagnetic stylet inside the endoscope's working channel. The most critical point is to obtain a blunt-bloodless ventriculostomy while achieving perfect alignment of all targeted structures via pure straight trajectories. CONCLUSIONS: This protocol is easy-to-set-up, avoids head rigid-fixation and bulky optical-based attachments to the ventriculoscope, and allows continuous navigation of both parts of the surgery. Since we have implemented this protocol, we have noticed a significant enhancement in both simple and complex ventriculoscopic procedures because the surgery is dramatically simplified.

Neuroendoscopic access to the third ventricle in patients with narrow foramen of monro without stenosis/obstruction: role of foraminoplasty.

OBJECT: One of the critical steps for the success of intraventricular neuroendoscopic procedures is the entry into the third ventricle and passage of the endoscopy system through the foramen of Monro (FM). A diameter larger than that of the instrument used is considered a prerequisite for safely performing the technique, as damage to this structure can lead to alterations in the fornix and vascular structures. When the foramen diameter is narrow and there is no obstruction/stenosis, the role of foraminoplasty in reducing the risk of complications has not been adequately assessed in the literature. METHODS: A review of endoscopic procedures conducted at our center since 2018 was undertaken. Cases in which preoperative imaging indicated a FM diameter < 6 mm and foraminoplasty technique was applied were examined to determine the technical and functional success of the procedure. The technical success was determined by completing the neuroendoscopic procedure with the absence of macroscopic lesions in the various structures comprising the foramen and without complications in the follow-up imaging tests. Functional success was defined as the absence of cognitive/memory alterations during the 3-month postoperative follow-up. Additionally, a review of the various forms of foraminoplasty described in the literature is conducted. RESULTS: In our cohort, six patients were identified with a preoperative FM diameter < 6 mm without obstruction or stenosis. Foraminoplasty was planned for these cases to facilitate various intraventricular neuroendoscopic procedures. In all instances, the technique was successfully performed without causing macroscopic damage to the structures comprising the foramen. Follow-up visits included various cognitive tests to assess potential sequelae related to microscopic damage to the fornix. None of the patients exhibited anomalies. CONCLUSION: Foraminoplasty in patients with a narrow FM without signs of stenosis/obstruction is a useful technique to reduce the risk of complications during the passage of the endoscopy system through this structure, enabling the safe performance of neuroendoscopic procedures.

Transcortical transcatheter ultrasound-assisted technique for deep-seated brain tumors. Technical note.

PURPOSE: Surgery of deep-seated brain tumors can be challenging. Several methods have been described to facilitate transcortical approaches, including ultrasound-assisted resection. Ultrasound-guided placement of a standard ventricular catheter is a widely reported technique and has been used to approach these lesions via the transcortical route. We describe how we usually perform this useful technique to assist and enhance the transcortical resection of some deep-seated brain tumors. METHODS: Standard electromagnetic frameless navigation (S8 Neuronavigation System, Medtronic, Minneapolis, USA) was employed to focus the craniotomy and to plan the trajectory of the ventricular catheter. After dural opening, an ultrasound device (Arietta 850, Hitachi-Aloka Medical, Tokyo, Japan) was used for intraoperative ultrasound (IOUS) assessment. A ventricular catheter was placed from the cortex to the lateral wall of the tumor under direct real-time IOUS visualization to guide the further transcortical dissection. RESULTS: Transcortical transcatheter ultrasound-assisted technique involved minimal time and infrastructure requirements. There were no major technical difficulties during its use, providing confidence and improving subcortical white matter dissection by guiding the route to the tumor. CONCLUSIONS: Recent improvement of IOUS image-quality devices offers several attractive options for real-time navigation. The combination of conventional neuronavigation systems with real-time IOUS assessment during the intradural step provides a higher degree of control by improving the execution of the surgery. We hope this description may be a useful tool for some selected cases and contribute to the further enhancement and improvement of this widely used technique.

Intraoperative ultrasound-assisted surgery in orbital apex tumours: technical note.

BACKGROUND: Since the introduction of ultrasonography (US) in the operating theatre in the early 1970s, intraoperative ultrasound (IOUS) has become a very useful tool for real-time neurosurgical procedures. The main limitation of US is its innately reduced capacity to penetrate the intact skull. This is the reason why most IOUS-assisted procedures are usually performed via transfontanellar or after a craniotomy or laminotomy is done. OBJECTIVE: We present a 54-year-old woman with a right optic nerve sheath meningioma, who was operated on by a right cranio-orbital approach and IOUS-assisted tumour removal. METHODS: Data concerning the anamnesis and complementary studies were obtained from the clinical history. Surgical images were obtained in the operating room during surgery. Images obtained by US were compared with the preoperative and postoperative imaging scans. IOUS imaging was also compared with the intraoperative findings. RESULTS: The correlation between US and both preoperative and postoperative studies was very high. During surgery, both transpalpebral and transperiorbital IOUS facilitated the resection with no specific technical difficulties or significant time consumption. CONCLUSION: Recent improvements in the image quality of IOUS devices offer several attractive options for real-time neuronavigation. We describe our initial experience with the IOUS-assisted technique for orbital apex tumours. In our patient transpalpebral and transperiorbital IOUS provided an excellent source of control over location and over the extent of tumour resection. We hope that this description of how we usually perform this procedure may be useful for some selected cases and contribute to the further enhancement and improvement of the technique.

Microsurgical training: vascular control and intraoperative vessel rupture in the human placenta infusion model.

BACKGROUND: Microsurgery is a challenging discipline. Regular lab training under the operating microscope has been the environment where most surgeons have mastered the skills and techniques inherent to most microneurosurgical procedures. However, some critical scenarios remain difficult to master or simulate. We describe a step-by-step method for how to build a low-cost, feasible, and widely available model that allows residents to familiarize themselves with demanding critical situations such as intraoperative rupture of major vessels. METHODS: After delivery, nine fresh human placentas were transferred to the lab. The umbilical vein was cannulated for normal saline infusion. Several hands-on procedures were performed under direct microscope vision. Operating microscope setup, allantoic membrane splitting, vascular dissection and vessel injury, and repair exercises were simulated and video recorded. Indocyanine green was administered to simulate intraoperative angiography. RESULTS: The model can be setup in less than 15 min, with minimal cost and infrastructure requirements. All the exercises described above can be conducted with a single placenta. Umbilical vein cannulation adds realism and allows quantification of the volume of saline required to complete the exercise. The final check with indocyanine green simulates intraoperative angiography and allows the assessment of distal vessel patency. CONCLUSIONS: Minimal infrastructure requirements, simplicity, and easy setup models provide a suitable environment for regular training. The human placenta is inexpensive and widely available, making it a feasible model for residents training. Neurosurgery residents may benefit from this model to familiarize with microsurgery and critical scenarios in a risk-free environment without time or resource constraints.

Neuroendoscopic training in neurosurgery: a simple and feasible model for neurosurgical education.

BACKGROUND: The development of high levels of technical competence and excellent decision-making skills are key goals of all neurosurgical residency training programs. This acquisition of technical skills is becoming increasingly difficult due to many factors including less exposure to operative cases, demand for more time and cost-effective practices, and resident work hour restrictions. We describe a step-by-step method for how to build a low-cost and feasible model that allows residents to improve their neuroendoscopic skills. METHODS: The bell pepper-based model was developed as an endoscopic training model. Using continuous irrigation, several hands-on procedures were proposed under direct endoscopic visualization. Endoscope setup, endoscopic third ventriculostomy, septostomy, and tumor biopsy procedures were simulated and video recorded for further edition and analysis. RESULTS: The model can be setup in less than 15 min with minimal cost and infrastructure requirements. A single model allows simulation of all the exercises described above. The model allows exposure to the camera skills, instrument handling, and hand-eye coordination inherent to most neuroendoscopic procedures. CONCLUSION: Minimal infrastructure requirements, simplicity, and easily setup models provide a proper environment for regular training. The bell pepper-based model is inexpensive, widely available, and a feasible model for routine training. Neurosurgery residents may benefit from the use of this model to accelerate their learning curve and familiarize themselves with the neuroendoscopic core principles in a risk-free environment without time or resource constraints.

Rotation flap closure of a giant dorsolumbar myelomeningocele: technical note.

PURPOSE: Myelomeningocele (MMC) is the most prevalent form of spina bifida aperta. Here we present the surgical repair technique of a dorsolumbar myelomeningocele with a large associated soft tissue defect. METHODS: Data concerning the anamnesis and complementary studies were obtained from the clinical history. Surgical images were obtained in the operation room during surgery. RESULT: We describe the case of a newborn with a dorsal myelomeningocele with a placode in the central area and a large associated skin defect of 12 x× 12 cm. Urgent intervention was carried out on the day of birth with placode reconstruction. Dorsal and gluteus maximus muscle rotation and skin rotation flap were performed in order to achieve complete closure of the myocutaneous defect. The patient presented a good recovery with no new neurological deficit. CONCLUSION: Myelomeningocele may be associated with large myocutaneous defects that can be difficult to correct by primary closure. In these cases, rotation flaps may be necessary to achieve complete closure.

Mature filum terminale teratoma. Excision guided by direct stimulation of nerve roots. / Teratoma maduro del filum terminale. Extirpación guiada por estimulación directa de raíces nerviosas.

A 45-year-old male patient, with no history of interest, consulted in emergency department due to a progressive loss of strength in the lower limbs at the distal level with impossibility for dorsal flexion of the left foot, as well as neurogenic bladder. The MRI revealed a mass at the filum terminale with completed occupation of transverse diameter of the dural sac. The radiological diagnosis was lipoma of filum terminale. The patient underwent surgery with intraoperative neurophysiological monitoring using direct stimulation of nerve roots, which allowed the removal of a tumour composed of sebaceous material, fat and hair. The anatomopathological study classified it as a mature cystic teratoma. Postoperative evolution was favorable.

Streptococcus intermedius posterior fossa abscess after a minor dental procedure in an immunocompetent woman. / Absceso en la fosa posterior por Streptococcus intermedius tras una limpieza dental en una paciente inmunocompetente.

A 52-year-old woman with no relevant previous medical history was diagnosticated of an infratentorial bulky cerebellar mass. The mass showed restricted diffusion on MR images, which was consistent with cerebellar abscess. The patient had undergone a minor dental procedure three weeks before. Microbiological analysis after surgical evacuation of the mass confirmed the presence of Streptococcus intermedius.

Ventriculostomy and endoscopic biopsy of pineal mass with hydrocephalus and unexpected definitive diagnosis. / Ventriculostomía y biopsia endoscópica de una masa pineal con hidrocefalia y diagnóstico final inesperado.

A 72-year-old female with no relevant medical history consulted in the emergency room for a two-week history of headache, vomiting and gait disturbance. Head CT scan revealed obstructive hydrocephalus secondary to a pineal mass with compression of the third ventricle. Magnetic Resonance showed another mass located in the right Lushcka foramen. Endoscopic third-ventriculostomy and biopsy of pineal mass were performed. Pathological analysis was consistent with metastasis of carcinoma. Full-body CT scan showed a lung mass related to primary carcinoma. The patient received systemic treatment for metastatic lung cancer. She died two months after diagnosis.

Late recurrence of medulloblastoma after 17 years of complete remission.

BACKGROUND: To describe an exceptional case of late recurrence of medulloblastoma after 17 years of complete remission. CASE DESCRIPTION: A 42-year-old male consulted in ER for 10-day occipital headache. He had a previous history of cerebellar medulloblastoma 17 years ago treated with gross total resection, chemotherapy and radiotherapy. During his yearly follow-up he had maintained complete remission. MRi showed a cerebellar mass suggestive of medulloblastoma recurrence vs radio-induced tumor. Craniotomy and complete resection of the tumor was performed. The anatomopathological analysis confirmed the recurrence of medulloblastoma. The patient received high dose of adjuvant chemotherapy and he maintains complete remission after 18 months. CONCLUSION: Recurrence of medulloblastoma may occur despite more than 15 years of complete remission. Because of this fact it is mandatory to continue the follow-up of these patients. Aggressive management of recurrence is recommended in absence of disease dissemination.

Misdiagnosis of posterior sequestered lumbar disc herniation: report of three cases and review of the literature.

INTRODUCTION: Posterior migration of sequestered disc is an extremely rare event that mimics more common spinal lesions as spinal tumors, making difficult its preoperative diagnosis and appropriate management. We retrospectively reviewed all lumbar disc herniations treated by surgery at our institution from 2006 to 2016 to identify cases with posterior sequestered disc fragments and possible misdiagnosis for other spinal lesions. Complementarily, a literature review of misdiagnosed cases of posterior migrated discs was undertaken. CASE REPORT: Three posterior sequestered lumbar disc cases (one intradural), were found among the 1153 reviewed surgeries. Two of them, presenting with progressive neurological deficit, were respectively misdiagnosed as pseudotumoral lesion and meningioma/neurogenic tumor on MRI. After intraoperative diagnosis and emergent resection, histology confirmed intervertebral disc tissue. The remaining case had an accurate preoperative diagnosis and after an initial conservative management finally underwent surgery because of refractory pain. Full recovery was achieved months after surgical treatment in all cases. DISCUSSION: Non-tumoral lesions are the most frequent misdiagnosis of posterior sequestered lumbar disc described in the literature. Early surgical treatment is the standard management due to high incidence of cauda equine syndrome (CES); however, spontaneous regression of posterior sequestered lumbar disc herniations has been recently reported. In conclusion low incidence and similar clinical and radiological features with other more common posterior spinal lesions like hematomas, synovial cyst or abscess turns posterior sequestered disc herniations a diagnosis challenge. Despite high incidence of CES, an initial conservative management should be evaluated in selected patients without neurological deficit and well-controlled pain.

Hypoglossal nerve paresis secondary to anterior approach of upper cervical spine followed by spontaneous recovery.

We describe an exceptional complication of cervical spine surgery in a 63-year-old male. He suffered the impact of a beam to the top of his head. During evaluation in the emergency room he reported intense neck pain with no other neurological symptoms or findings on physical examination. Spine computed tomography (CT) showed C3 vertebral body fracture that required surgical stabilization. A right side anterior approach to upper cervical spine with C3 corpectomy and placement of iliac bone autograft was performed. After surgery the patient presented dysphagia, dysarthria and limitation tongue mobility to the right side. These findings were consistent with hypoglossal neuropraxia probably related to soft tissue traction generated by the upper part of the self-retaining retractor. After discharge the patient experienced spontaneous improvement of hypoglossal paresis.

[Incidence and risk factors of 30-day readmission in neurosurgical patients]. / Incidencia y factores de riesgo de reingreso hospitalario a los 30 días en pacientes neuroquirúrgicos.

AIM: The 30-day readmission rate has become an important indicator of health care quality. This study focuses on the incidence of 30-day readmission in neurosurgical patients and related risk factors. MATERIAL AND METHODS: A retrospective review was performed on patients treated in a neurosurgery department between 1 January 2012 and the 31 December 2013. Patients requiring readmission within 30 days of discharge and the readmission diagnosis were identified, and the factors related to their readmission were analysed. RESULTS: A total of 1,854 interventions were carried out on 1,739 patients during the aforementioned (study) period. Of the remaining patients, 174 (10.2%) required readmission within 30 days of discharge. The main causes of readmission were problems related to the surgical wound (21.2% of all readmissions), followed by respiratory processes (18.8%). A total of 73.9% of readmissions occurred in patients who had undergone cranial surgery. Multiple comorbidities estimated by Charlson comorbidity index and length of hospital stay were identified as factors related to a higher readmission rate. CONCLUSIONS: The 30-day readmission rate observed in our series was 10.2%. Multiple comorbidity expressed by the Charlson comorbidity index and length of hospital stay were related to readmission.

[Anterior and anterolateral approach in the treatment of thoracic and lumbar vertebral metastasis causing spinal cord compression]. / Abordaje anterior y anterolateral en el tratamiento de la compresión medular metastásica a nivel torácico y lumbar.

OBJECTIVES: To analyse the results of the anterior and anterolateral approaches in the treatment of thoracic and lumbar spine metastasis. MATERIALS AND METHODS: Patients who underwent surgery between 2003 and 2012 in our institution using an anterior or an anterolateral approach for the treatment of thoracic or lumbar spine metastasis were retrospectively reviewed. RESULTS: Twenty-two patients with median age of 49.5 years (26-73 years) and median follow-up of 9.5 months (0-96 months) were analysed. The most common primary malignancies were renal cell carcinomas and breast adenocarcinomas. Before the intervention, 12 (54.5%) patients were able to walk (Frankel D and E). Preoperative arteriography was performed in 14 (63.6%) patients, and 7 (31.8%) of them underwent tumour embolisation. Medical complications occurred in 5 (22.7%) patients during the immediate postoperative period, 2 (9.1%) of whom died. At the end of follow-up, 16 (72%) of the remaining 20 patients were able to walk (Frankel D and E). Ninety percent of the patients could reduce at least 50% of their analgesic drug requirements. During follow-up 16 patients died, with a median survival of 10 months (range 0-48 months). CONCLUSIONS: Resection of thoracolumbar vertebral metastases by an anterior/anterolateral approach, despite its considerable risk of morbidity and mortality, offers the possibility of significant improvement in the quality of life of the patient; and it does so not only by preserving or restoring their ability to walk but also by ameliorating pain. Preoperative angiography, considering the embolisation of the lesion, is an important tool.