Intraoperative computed tomography, navigated ultrasound, 5-amino-levulinic acid fluorescence and neuromonitoring in brain tumor surgery: overtreatment or useful tool combination?

BACKGROUND

Brain tumor surgery is routinely supported by several intraoperative techniques, such as fluorescence, brain mapping and neuronavigation, which are often used independently. Efficacy of navigation is limited by the brain-shift phenomenon, particularly in cases of large or deep-sited lesions. Intraoperative imaging was introduced also to update neuronavigation data, to try and solve the brain-shift phenomenon-related pitfalls and increase overall safety. Nevertheless, each intraoperative imaging modality has some intrinsic limitations and technical shortcomings, making its clinical use challenging. We used a multimodal intraoperative imaging protocol to update neuronavigation, based on the combination of intraoperative Ultrasound (i-US) and intraoperative Computed Tomography (i-CT) integrated with 5-ALA fluorescence and neuromonitoring-guided resection.

METHODS

This is a pilot study on 52 patients (29 men), including four children, with a mean age of 57.67 years, suffering from brain low- (N.=10) or high-grade (N.=34) glioma or metastasis (N.=8), prospectively and consecutively enrolled. They underwent 5-ALA fluorescence-guided microsurgical tumor resection and neuromonitoring was used in cases of lesions located in eloquent areas, according to preoperative clinical and neuroradiological features. Navigated B-mode ultrasound acquisition was carried out after dural opening to identify the lesion. After tumor resection, i-US was used to identify residual tumor. Following further tumor resection or in cases of unclear US images, post-contrast i-CT was performed to detect and localize small tumor remnants and to allow further correction for brain shift. A final i-US check was performed to verify the completeness of resection. Clinical evaluation was based on comparison of pre- and postoperative Karnofsky Performance Score (KPS) and assessment of overall survival (OS) and progression-free survival (PFS). Extent of tumor resection (EOTR) was evaluated by volumetric postoperative Magnetic Resonance performed within 48 h after surgery.

RESULTS

Forty-one of the 52 (78.8%) patients were alive and still under follow-up in December 2017. 5-ALA was strongly or vaguely positive in 45 cases (86.5%). Seven lesions (four low-grade glioma, one high-grade glioma, and two metastases) were not fluorescent. i-US visualized residual tumor after resection of all fluorescent or pathological tissue in 22 cases (42.3%). After i-US guided resection, i-CT documented the presence of further residual tumor in 11 cases (21.1%). Mean EOTR was 98.79% in the low-grade gliomas group, 99.84% in the high-grade gliomas group and 100% in the metastases group. KPS changed from 77.88, preoperatively, to 72.5, postoperatively. At the last follow-up, mean KPS was 84.23.

CONCLUSIONS

The combination of different intraoperative imaging modalities may increase brain tumor safety and extent of resection. In particular, i-US seems to be highly sensitive to detect residual tumors, but it may generate false positives due to artifacts. Conversely, i-CT is more specific to localize remnants, allowing a more reliable updating of navigation data.

Craniovertebral Junction Surgical Approaches: State of Art

Surgical approaches directed toward craniovertebral junction (CVJ) can be addressed to the ventral, dorsal, and lateral aspects through a variety of 360° surgical corridors Herein, we report features, advantages, and limits of the updated technical support in CVJ surgery in clinical setting and dissection laboratories enriched by our preliminary surgical results of the simultaneous application of O-arm intraoperative neuronavigation and imaging system along with the 3D-4K EX in TOA for the treatment of CVJ pathologies.In the past 4 years, eight patients harboring CVJ compressive pathologies underwent one-step combined anterior neurosurgical decompression and posterior instrumentation and fusion technique with the aid of exoscope and O-arm. In our equipped Cranio-Vertebral Junction Laboratory, we use fresh cadavers (and injected "head and neck" specimens) whose policy, protocols, and logistics have already been elucidated in previous works. Five fresh-frozen adult specimens were dissected adopting an FLA. In these specimens, a TOA was also performed, as well as a neuronavigation-assisted comparison between transoral and transnasal explorable distances.A complete decompression along with stable instrumentation and fusion of the CVJ was accomplished in all the cases at the maximum follow-up (mean: 25.3 months). In two cases, the O-arm navigation allowed the identification of residual compression that was not clearly visible using the microscope alone. In four cases, it was not possible to navigate C1 lateral masses and C2 isthmi due to the angled projection unfitting with the neuronavigation optical system, so misleading the surgeon and strongly suggesting changing surgical strategy intraoperatively. In another case (case 4), it was possible to navigate and perform both C1 lateral masses and C2 isthmi screwing, but the screw placement was suboptimal at the immediate postoperative radiological assessment. In this case, the hardware displacement occurred 2 months later requiring reoperation.

Repeated surgery for hemorrhagic brain metastases from hepatocellular carcinoma: palliation or effective part of a multimodal treatment? A case-based approach

Brain metastases from hepatocellular carcinoma (HCCBM) are encountered very rarely in clinical practice, especially in western countries. Only a minority of patients undergoes resective surgery, as clinical picture is usually complex and presentation is often catastrophic with intra-cerebral hemorrhage (ICH). Neurosurgical intervention can be not only life-saving but may also alleviate significantly the burden of symptoms. We present the case of a patient with six metachronous hemorrhagic HCCBM in which emergent surgery extended survival by 9 months, of which seven spent in near-normal life quality, stressing the role of neurosurgery in the evaluation of HCCBM patients.

Assessing the Training in Neurosurgery with the Implementation of VITOM-3D Exoscope: Learning Curve on Experimental Model in Neurosurgical Practice

(1) Background: Innovation and continuous demand in the field of visual enhancing technologies and video streaming have led to the discovery of new systems capable of improving visualization and illumination of the surgical field. The exoscope was brought into neurosurgical routine, and nearly ten years later, modern 3D systems have been introduced and tested, giving encouraging results. (2) Methods: In order to evaluate the surgeon's confidence with the exoscope and their increasing ability in terms of time spent and quality of the final achievement since their first encounter with the technique, an experimental trial on 18 neurosurgeons from a single Institution was performed to evaluate the learning curve for the use of the VITOM-3D exoscope in neurosurgical practice on a model of brain and dura mater. (3) Results: A significant improvement in the quality of the performance, number of errors made, and reduction in the time was found after the third iteration of the task, by when almost all the participants felt more comfortable and confident. No significant differences between senior neurosurgeons and resident neurosurgeons were reported. (4) Conclusions: Our results show that three iterations are enough to gain confidence with the exoscope from its first use, regardless of previous experience and training with an operating microscope.

Through the orbit and beyond: Current state and future perspectives in endoscopic orbital surgery on behalf of the EANS frontiers committee in orbital tumors and the EANS skull base section

Introduction

Orbital surgery has always been disputed among specialists, mainly neurosurgeons, otorhinolaryngologists, maxillofacial surgeons and ophthalmologists. The orbit is a borderland between intra- and extracranial compartments; Krönlein's lateral orbitotomy and the orbitozygomatic infratemporal approach are the historical milestones of modern orbital-cranial surgery.

Research question

Since its first implementation, endoscopy has significantly impacted neurosurgery, changing perspectives and approaches to the skull base. Since its first application in 2009, transorbital endoscopic surgery opened the way for new surgical scenario, previously feasible only with extensive tissue dissection.

Material and methods

A PRISMA based literature search was performed to select the most relevant papers on the topic.

Results

Here, we provide a narrative review on the current state and future trends in endoscopic orbital surgery.

Discussion and conclusion

This manuscript is a joint effort of the EANS frontiers committee in orbital tumors and the EANS skull base section.

Diffuse idiopathic skeletal hyperostosis: A functional enemy of vertebral stability - Case series and surgical consideration of craniovertebral junction involvement

Context

Diffuse idiopathic skeletal hyperostosis (DISH) or Forestier's syndrome may reduce vertebral mobility, thus affecting the stability of adjacent vertebral segments and promoting spinal stenosis, vertebral dislocation, and unstable fracture secondary to low-energy trauma.

Aims

This study aimed to contribute with a case series of three patients affected by DISH undergone surgery with occipitocervical fixation for craniovertebral junction (CVJ) instability since the poor literature about CVJ instability and surgery in patients affected by DISH.

Settings and Design

This was a multicentric case series.

Subjects and Methods

Literature about CVJ instability and surgery in patients affected by DISH is poor. Thus, we present a case series of three patients affected by DISH, who underwent surgery with occipitocervical fixation with different clinical and radiological patterns.

Results

CVJ represents one of the most mobile joints of the spine and is at greater risk for instability. Moreover, instability itself may act as primum movens for several degenerative conditions such as cervical spondylosis, ossification of the posterior longitudinal ligament, and cervical deformities. On the contrary, DISH itself may worsen CVJ instability because of subaxial spine stiffness. In case of DISH, the rigid unit formed by several ossified vertebral bodies acts as a long lever arm, increasing the forces applied to the hypermobile CVJ and reducing the dynamic buffer capability of ossified spine. On the other hand, vertebral instability increases the odds of fractures. In such cases, CVJ posterior instrumentation and fusion is an effective and feasible surgical technique, aimed to restore vertebral stability and to halt the progression of spinal stenosis.

Conclusions

Due to the altered dynamics cervical spine along with the possible comorbidities, treatment indication and surgery for patients affected by DISH must be tailored case by case.

Differences in intraoperative sampling during meningioma surgery regarding CNS invasion - Results of a survey on behalf of the EANS skull base section

Introduction

and Research Question: Invasive growth of meningiomas into CNS tissue is rare but of prognostic significance. While it has entered the WHO classification as a stand-alone criterion for atypia, its true prognostic impact remains controversial. Retrospective analyses, on which the current evidence is based, show conflicting results. Discordant findings might be explained by different intraoperative sampling methodologies.

Material and methods

To assess the applied sampling methods in the light of the novel prognostic impact of CNS invasion, an anonymous survey was designed and distributed via the EANS website and newsletter. The survey was open from June 5th until July 15th, 2022.

Results

After exclusion of 13 incomplete responses, 142 (91.6%) datasets were used for statistical analysis. Only 47.2% of participants' institutions utilize a standardized sampling method, and 54.9% pursue a complete sampling of the area of contact between the meningioma surface and CNS tissue. Most respondents (77.5%) did not change their sampling practice after introduction of the new grading criteria to the WHO classification of 2016. Intraoperative suspicion of CNS invasion changes the sampling for half of the participants (49.3%). Additional sampling of suspicious areas of interest is reported in 53.5%. Dural attachment and adjacent bone are more readily sampled separately if tumor invasion is suspected (72.5% and 74.6%, respectively), compared to meningioma tissue with signs of CNS invasion (59.9%).

Discussion and conclusions

Intraoperative sampling methods during meningioma resection vary among neurosurgical departments. There is need for a structured sampling to optimize the diagnostic yield of CNS invasion.

Cystic Dilatation of the Ventriculus Terminalis: Examining the Relevance of the Revised Operative Classification Through a Systematic Review of the Literature, 2011-2021

The literature features limited evidence on the natural history of the cystic dilatation of the ventriculus terminalis (CDVT) and its response to treatment. The goal of this study is to ascertain which impact the revised operative classification of CDVT had on the management of patients diagnosed over the past 10 years.Ten new clinical articles presenting a total of 30 cases of CDVT were identified and included for qualitative analysis. Two take-home messages can be identified: (1) Adequate consideration should be given to designing national pathways for referral to tertiary centers with relevant expertise in the management of lesions of the conus medullaris, and (2) we suggest that type Ia should be, at least initially, treated conservatively, whereas we reckon that the signs and symptoms described in types Ib, II, and III seem to benefit, although in some patients only partially, from surgical decompression in the form of cystic fenestration, cyst-subarachnoid shunting, or both.While the level of evidence gathered in this systematic review remains low because the literature on CDVT consists only of retrospective studies based on single-center series (level of evidence 4 according to the Oxford Centre for Evidence-Based Medicine (OCEBM)), the strength of recommendation for adopting the revised operative classification of CDVT is moderate.

Hybrid Implants in Anterior Cervical Spine Surgery: The State of the Art and New Trends for Multilevel Degenerative Disc Disease

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) still represents the first surgical option in the treatment of cervical degenerative disc disease (DDD) but is still burdened by several complications secondary to the loss of mobility at the treated segment and adjacent segment diseases (ASDs). To overcome those complications, hybrid surgery (HS) incorporating ACDF and cervical disc arthroplasty (CDA) is increasingly performed for DDD.

METHODS

We retrospectively reviewed the clinical, surgical, and outcome data of 85 consecutive patients (M/F, 41/44) harboring cervical disc herniation with or without osteophytes, with radiculopathy and with or without myelopathy, who underwent the anterior approach to a cervical discectomy on two or more levels with at least one disc prosthesis, along with a cage and plate or an O Profile screwed plate.

RESULTS

All the patients improved regardless of the cervical construct used. No significant relationship between different kinds of prosthesis and their surgical level; the number of cages; and the site of the cages (screwed and/or plated) was found concerning immediate stability, dynamic prosthesis effectiveness, and clinical improvement in all the patients up to the maximum follow-up time.

CONCLUSIONS

Although the optimal surgical technique for cervical DDD remains controversial, HS represents a safe and effective procedure in select patients with multilevel cervical DDD, as demonstrated by biomechanical and clinical studies and the present series.

Percutaneous Balloon Compression for Trigeminal Neuralgia. A Comparative Study Between the Fluoroscope Guided and Neuronavigated Technique

Percutaneous balloon compression (PBC) is a safe and effective procedure in the treatment of trigeminal neuralgia (TN) due to its simplicity, low cost and the possibility of being repeated in case of pain recurrence. Foramen ovale (FO) cannulation is accomplished with the assistance of intraoperative C-arm fluoroscopy. Recently, several authors have reported successful application of intraoperative CT navigation as well. The reported advantages of CT navigation are linked to better spatial orientation and the low rate of attempts for FO cannulation. However, these advantages should be considered in the face of concerns regarding increased radiation dose to the patient and its possible adverse effects. Here we compared the fluoroscopic guided and neuronavigated PBC techniques in terms of efficacy and radiological exposure. We retrospectively analyzed 37 patients suffering for TN and submitted to PBC. We observed a significant improvement of pain at 1 month FU compared with the pre-operative in both groups (p < 0.0001 and p < 0.0001, respectively). A significant increase in radiation exposure was found in the neuronavigated group compared with the fluoroscopy group (p < 0.0001). We suggest the use of neuronavigated PBC only in selected cases, such as patients with multiple previous operations, in whom a difficult access can be pre-operatively hypothesized.

The Role of the Anesthesiologist and the Modern Intraoperative Echography in Ventriculoatrial Shunt for Hydrocephalus: From Hakim to Nowadays

The introduction of US-guided venipuncture in clinical practice has greatly facilitated the surgical approach to patients with hydrocephalus. Especially in infants and children, where it results in a lower technical failure rate, less time and fewer complications than the traditional referral method, this technique has become a clinical protocol. This dynamic or "real time" technique has become one of the anesthetist's tools. This allowed the anesthesiologists to be part of the surgical team, so they not only dedicate themselves to inducing and maintaining general anesthesia but also to performing venipuncture of the central vein of the neck and to locating the tip of the catheter.The anesthetist's tools have made it possible to perform a simple and safe method, and the anesthesiologists have become an active part of the surgical team, charged with a specific role during the positioning of the ventricular atrial shunt.

Image-Guided Surgery in Complex Skull Base and Facial Fractures: Initial Experience on the Role of Intra-Operative Computer Tomography

Surgery of fractures involving the skull base and the facial skeleton often presents challenges that should be addressed to prevent secondary brain injuries (i.e., cerebro-spinal fluid leak), preserve visual functioning, and guarantee a good esthetic result. Complex craniofacial reconstruction can be aided by navigation and pre-operative planning. In recent years, computerized planning of surgical reconstruction drastically increased the safety and efficacy of surgery, but the impact of intraoperative high quality image devices such as an intraoperative computed tomography (CT) scan has not been investigated yet. This case-control study reports the institutional preliminary experience of using intraoperative CT scans in the surgical management of complex cranio-facial fractures. The results in terms of accuracy of bony reconstruction and neurological or surgical complications have been analyzed in 12 consecutive patients treated with (6 cases) or without (6 cases) i-CT. Comparative analysis demonstrated a greater accuracy of reconstruction in patients treated with the assistance of i-CT. Intraoperative CT is a useful tool with a promising role in a multidisciplinary surgical approach to complex cranio-facial surgery.

Chiari Malformation Type 1 and Syringomyelia: Why Do Patients Claim for International Guidelines? Commentary on the 2021 Chiari and Syringomyelia Consensus Document

The diagnosis of Chiari malformation type 1 (CM1) and Syringomyelia (Syr) has become increasingly common during the past few years. Contemporarily, the body of literature on these topics is growing, although randomized controlled studies on significant case series to drive guidelines are missing in the pediatric and adult populations. As a result of the different opinions about surgical indications and techniques raised by CM1-Syr, an increasing number of well-informed but disoriented patients is emerging. To bridge this gap, an International Consensus Conference on CM1-Syr held in Milan in November 2019 aimed to find a consensus among international experts, to suggest some recommendations that, in the near future, could lead to guidelines. Here, we comment on the most relevant recommendations about the definition, diagnosis, surgical management, failures and re-intervention, and outcome. We also focus on some "wrong" indications or techniques that, although widely disapproved by the experts, and negatively experienced by many patients, are still largely in use.

Toward the End of the Funnel: The Ventriculus Terminalis-The State of Art of an Ancient Entity with a Recent History

PURPOSE

The ventriculus terminalis (VT), also called the fifth ventricle, is a small cavity containing cerebrospinal fluid (CSF) that is in the conus medullaris in continuity with the central canal of the spinal cord. In adults, persistent VT is a very rare entity, and the diagnosis is incidental in most cases. Rarely, VT may become symptomatic for still-uncertain reasons but most often for its cystic dilatation. The management of these selected cases is still controversial and sometimes associated with unsatisfactory outcomes.

METHODS

We performed a critical review of the existing literature on the management of symptomatic VT in adults. The etiology, pathophysiology, and treatment of VT are presented and discussed, focusing on the best timing for surgery.

RESULTS

Conservative management, marsupialization, or the placement of a T drain have been reported. The existing classifications describe the most correct approach for each clinical presentation, but scarce importance has been given to the delay from symptoms' onset to surgical treatment.

CONCLUSION

Although different cases have been described in the literature, this rare pathology remains unknown to most neurosurgeons.

Direct Transpedicular C2 Fixation for the Surgical Management of Hangman's Fractures: A "Second Youth" for the Judet Approach

PURPOSE

The optimal management of hangman's fractures is controversial and the standard of care has been neither established nor supported by strong evidence. The Judet approach has been introduced in 1970 as surgical option to treat selected cases of hangman's fractures, harboring the advantage to preserve motion of the craniovertebral junction and to restore the C2 vertebra anatomy by insertion of transpedicular screws through the fracture line. This paper reviews the literature on hangman's fractures surgically managed by Judet approach, and reports two new illustrative cases.

METHODS

The PubMed database was searched for the review process. After initial screening of abstracts and papers, 13 manuscripts were included in the present review.Two cases of hangman's fractures, a Levine-Edwards type I and a type IIA, respectively, treated with direct transpedicular C2 screw fixation are reported. Surgical steps of the Judet approach are also described.

RESULTS

Our literature review revealed that the technique described by Judet is gaining appeal only in recent years and there is no consensus on surgical indications.No surgery-related complications were observed in the two reported cases. Patients experienced a significant reduction of neck pain postoperatively. Motion of craniovertebral junction was preserved in both patients at 3-, 6-, and 12-month follow-ups.

CONCLUSIONS

Direct transpedicular osteosynthesis of C2-pars interarticularis fracture has been already demonstrated as effective in type II and IIA hangman's fractures. The application of such technique in selected patients with atypical type I fractures should also be considered in order to achieve early mobilization and avoid external fixation.

Emergency Treatment of Cervical Vertebromedullary Trauma: 10 Years of Experience and Outcome Evaluation

OBJECTIVE

The aim of the study is to identify and validate, through the recording of clinical and radiological data, the different surgical approaches and treatments valid for most subaxial cervical dislocation fractures and whether there is an advantage from using an anterior approach rather than a posterior approach and conversely..

MATERIAL AND METHODS

A retrospective study was carried out analyzing the case history of the last 10 years of vertebromedullary traumas treated at the spine surgery unit of the Policlinico Gemelli in Rome. Data on surgical timing, American Spinal Injury Association (ASIA) scores for neurological damage, and subsequent assessments on recovery, survival, and mortality were also examined.

RESULTS

A total of 80 patients were treated: 50 by the posterior approach, 24 by the anterior approach, and six by the double approach. Our average follow-up time was 4.2 years. A prevalence of surgery with the posterior approach was noted. We observed the worsening of cervical kyphosis about 15 months after the trauma in two cases treated with the posterior approach alone. A second surgical treatment was performed in these patients. One of these patients underwent an anterior fusion; the other case underwent a posterior revision because the patient had ankylosing spondylitis. Although we found no statistically significant difference in outcomes between the various surgical treatments, in this retrospective study, we analyzed the characteristics and outcomes of cervical spine injuries that required surgical treatment.

CONCLUSION

The aim of surgery in unstable cervical spine injuries should be to reduce and stabilize the damaged segment, maintain lordosis, and decompress when indicated. The optimal choice of surgical approach and treatment, or its superiority in terms of outcomes, remains a debated issue.

The Thoracoscopic Approach in Spinal Cord Disease

Video-assisted thoracic surgery (VATS) has been growing in popularity over the past 2 decades as an alternative to open thoracotomy for the treatment of several spinal conditions, and in the field of minimally invasive surgery, it now acts as a keyhole to the thoracic spine.

MATERIALS AND METHODS

Most VATS approaches are from the right side for pathologies involving the middle and upper thoracic spine because there is a greater working spinal surface area lateral to the azygos vein than that lateral to the aorta. Below T-9, a left-sided approach is made possible because the aorta moves away from the left posterolateral aspect of the spine to an anterior position as it passes through the diaphragm.

RESULTS

VATS has been used extensively in spinal deformities such as scoliosis. The use of VATS in spine surgery includes the treatment of thoracic prolapsed disk diseases, vertebral osteomyelitis, fracture management, vertebral interbody fusion, tissue biopsy, anterior spinal release, and fusion without or with instrumentation (VAT-I) for spinal deformity correction. As the knowledge and the comfort of using such techniques have expanded, the indications have extended to corpectomy for tumor resections.

DISCUSSION AND CONCLUSIONS

In the field of minimally invasive surgery, VATS now acts as a keyhole to the thoracic spine and an alternative to open thoracotomy for the treatment of several spinal conditions.Although VATS can be performed in such spine conditions, it is most beneficial in the treatment of scoliotic deformity, which requires taking a multilevel approach, from the upper to the lower thoracic spine.

Technologies in Anaesthesia for the Paediatric Patient

Spine surgery is an increasingly frequent surgery and includes a wide range of procedures, from minor surgeries (removal of herniated discs, simple laminectomies) to major surgeries (arthrodesis, removal of spinal meningiomas, etc.).These surgeries commonly involve complex patients (elderly population, ASA II-III) and are sometimes performed in emergency settings (polytrauma, cauda syndrome, pathological fractures), which require specific positions (pronation or lateral decubitus), whereby there can be difficulty in airway management, especially in surgeries that concern the cervical tract.One of the main peculiarities of spine surgery involves the prone position.Patient positioning on the operating bed is an action that must be carried out under medical supervision, in particular by the anaesthetist who is supposed to supervise the regular positioning of the patient at the very moment in which it is performed. The correct positioning of the patient is one of the most important moments of the patient care process in the operating room, given that an error in this field may cause serious damage to the patient by giving rise to permanent and significant nerve damage.The prone position is associated with a variety of complications (Kwee et al., Int Surg 100(2): 292-303, 2015). The points of greatest compression during pronation are eyes, nose, breasts, genitals and neck veins.Therefore, the main risks that can derive from an incorrect position are visual disturbances from inappropriate orbital compression, brachial plexus stretching, ulnar nerve compression and lateral femur-cutaneous nerve stretching. In addition, an inappropriate compression of the abdominal organs in this position, may cause ischemia and consequent organ failure resulting in hospitalization prolongation, permanent disability and sometimes even death (Edgcombe et al., Br J Anaesth 100: 165-183, 2008).In addition to the mechanical effects on anatomical structures, there are also the physiological effects of the prone position, which can be divided into circulatory and respiratory effects.These effects are even more pronounced in elderly patients, cardiopaths or patients with respiratory diseases.

Why the Funnel in Neurosurgery?

According to Cambridge Dictionary, Funnel is an object that has a wide round opening at the top, sloping sides, and a narrow tube at the bottom, used for pouring liquids or powders into containers with narrow necks.From an semplified anatomic point of view, the skull base along with its offshoot, the spine, replicate a bone funnel as a vessel sustaining the brain, the cerebellum and the spinal cord along with cranial and radicular nerves. Non doubt at all that the knowledge of the embryology, anatomy, physiology, pathophysiology and the more effective surgical pathways to engage and remove surgical diseases is of paramount importance in the surgical cultural heritage to be strongly encouraged and supported in young neurosurgeons.So to the steps that seem to emerge from this Issue of Acta Neurochirurgica suppl are exploratory, strategic, tactical and finally operational. From the skull base to the sacrum we meet a macrosystem of anatomic and functional complex network with a common embryological hystory as well as contiguity. Different skills are necessary to face with a 360° universe of functions and diseases to deal with. Intelligence and culture as knowledge of both anatomy and pathology help to elaborate the STRATEGY while technical and manual supports are part of the TACTIC armamentarium which is proactive and determinant to the final OPERATIONAL step.

Petroclival Clinoidal Folds and Relationships with Arachnoidal Membranes of Medial Incisural Space: Old Neuroanatomical Terms for a New Neurosurgical Speech in Cadaver Labs with Limited Resources Era. Part III: Arachnoid Membranes, Cranial Nerves, and Surgical Implications

BACKGROUND Anatomical dissections play an irreplaceable role in the training of new generations of effective neurosurgeons, especially when addressing skull base lesions is required.The Authors describe an inter-laboratory dissection study aimed at improving the knowledge of a complex region of the skull base. The anterior and middle incisural spaces are of remarkable anatomical and surgical interest due to complex relationships between bony, dural, arachnoidal, and neurovascular structures. The primary purposes of this study are to describe the anatomy of this region with particular emphasis on the relationships between the anterior margin of the free edge of the tentorium and the sphenoid and petrous bone; to identify surgical implications in many different types of neurosurgical procedures dealing with this challenging complex anatomic area.METHODS Thirteen anatomical specimens, including five injected specimens, were dissected in this study. In the formalin-fixed specimens, vessels were injected with colored silicone.RESULTS The anatomical study focused on the description of the relationships between bony dural, arachnoid, and neurovascular structures. Surgical implications are described accordingly.CONCLUSIONS Detailed anatomical knowledge of this region finds concrete applications in neurosurgical practice since the anterior and middle incisural spaces are often surgically exposed in neoplastic and vascular diseases. The high-definition pictures reported in this study could represent useful support to understand the anatomy of this complex region.Finally, our study could provide guidance to neurosurgical centers in which resources are limited that are either planning to establish their own cadaver dissection laboratory or failed to do so because of the supposed high-costs.

Petroclival Clinoidal Folds and Relationships with Arachnoidal Membranes and Neural Structures of Anterior and Middle Incisural Spaces: Old Neuroanatomical Terms for a New Neurosurgical Speech in Cadaver Labs with Limited Resources Era. Part I: Osteology and Structural Anatomy of Dura Mater

Purpose The role of cadaver labs in preparing new generations of effective neurosurgeons is of paramount importance. The Authors describe a personal cadaver lab experience aimed at improving the knowledge of a difficult region of the central skull base. The anterior and middle incisural spaces are regions of remarkable anatomical, and surgical interest due to complex relationships between bony, dural, arachnoidal, and neurovascular structures. The primary purpose of this study is (1) to describe the anatomy of this region with particular emphasis on the relationships between the anterior margin of the free edge of the tentorium and the sphenoid and petrous bone; (2) to identify surgical implications in many different types of neurosurgical procedures dealing with this challenging complex anatomic area.Methods Eight fresh, non-formalin-fixed non-silicon-injected adult cadaver heads and five injected formalin-fixed adult cadaver heads were analyzed in this study.Results The anatomical study was focused on the description of the relationships between bony, dural, arachnoid, and neurovascular structures. Surgical implications are described accordingly.Conclusions Detailed anatomical knowledge of this region finds concrete applications in neurosurgical practice since the anterior and middle incisural spaces are often surgically exposed in neoplastic and vascular diseases.

The Submandibular Approach: A Descriptive Perspective of the Retropharingeal Corridor to the Craniocervical Junction (Microscopic- vs. Endoscopic-Assisted Dissections)

The craniocervical junction refers to an area from the line separating the middle and lower third of the clivus to the base of the dens (anteriorly) and from the posterior edge of the occipital foramen to the spinous process of C2 (posteriorly). Here, the clival region is a challenging surgical target surrounded by a complex neurovascular architecture. Historically, mainly the complex, and high-risk, transmucosal approaches have been the corridors of choice when targeting this region. Nevertheless, the inherent broad anatomic and pathological variants have shown the need for more-malleable and wider approaches. Thus, MacAfee's established retropharyngeal approach has been simplified in parallel to the application of endoscopic surgery, therefore providing access to the clival region through a low-risk retropharyngeal space when compared to homologous anterior transmucosal approaches. The following review analyzes the literature that has specifically described the craniocervical junction after reaching the clivus (or at least after odontoidectomy) through the retropharyngeal corridor, from the perspective of the open approach or the endoscopic submandibular approach.

Spinal Cord High-Frequency Stimulation. The Current Experience and Future Directions

Spinal cord stimulation (SCS) is a neuromodulation technology that has emerged as a valid treatment for chronic intractable neuropathic pain. After conventional tonic SCS, new waveforms of stimulation, like high frequency (HF), have proved that they can provide safe and effective pain relief. In addition, SCS is now being utilized more broadly as a potential treatment for a range of indications, including motor disorders and spasticity. Our study presents a retrospective analysis of 20 patients with heterogenous aetiologies of neuropathic pain treated with HF stimulation, after a standardized protocol in a temporary trial. We observed a significant improvement in pain relief according to comparisons of numerical rating scale (NRS) scores before the procedure, after the clinical trial and at latest follow-up. Two unusual clinical cases were also reported, and the pertinent literature was discussed.

Supraorbital Keyhole Versus Pterional Approach: A Morphometric Anatomical Study

OBJECTIVE

Although the supraorbital (SO) keyhole approach has a wide range of indications, its routine usefulness with the advance of current technology has not been fully evaluated. In an attempt to address this issue, a cadaveric morphometric analysis to the supra- and parasellar regions was performed, comparing the standard Pterional craniotomy (PT) with the SO keyhole.

METHODS

ETOH-fixed and silicone-injected human cadaveric heads were used. SO (n = 8) and PT craniotomies (n = 8) were performed. Pre- and post-dissection CT, along with pre-dissection MRI scans were also completed for neuro-navigation purposes, aimed to verify predetermined anatomical landmarks selected for morphometric analysis.

RESULTS

Notwithstanding the smaller craniotomy, the SO approach allowed optimal anatomical exposure when compared to the PT approach. With 30° of head rotation, the SO keyhole showed a wider surgical field of the suprasellar region.

CONCLUSIONS

Using detailed preoperative image-guided surgical planning, the SO keyhole approach offered an appropriate alternative route to the supra- and parasellar regions, compared to the PT craniotomy.

Petroclival Clinoidal Folds and Relationships with Arachnoidal Membranes of Anterior and Middle Incisural Spaces: Old Neuroanatomical Terms for a New Neurosurgical Speech in Cadaver Labs with Limited Resources Era. Part II: Free Edge of the Tentorium, Petroclinoid Folds, and Incisural Spaces

BACKGROUND Anatomical dissections play an irreplaceable role in the training of new generations of effective neurosurgeons, especially when addressing skull base lesions is required.The Authors describe an inter-laboratory dissection study aimed at improving the knowledge of a complex region of the skull base. The anterior and middle incisural spaces are of remarkable anatomical and surgical interest due to complex relationships between bony, dural, arachnoidal, and neurovascular structures. The primary purposes of this study are to describe the anatomy of this region with particular emphasis on the relationships between the anterior margin of the free edge of the tentorium and the sphenoid and petrous bone; to identify surgical implications in many different types of neurosurgical procedures dealing with this challenging, complex anatomic area.METHODS Thirteen anatomical specimens, including five injected specimens, were dissected in this study. In the formalin-fixed specimens, vessels were injected with colored silicone.RESULTS The anatomical study was focused on the description of the relationships between bony dural, arachnoid, and neurovascular structures. Surgical implications are described accordingly.CONCLUSIONS Detailed anatomical knowledge of this region finds concrete applications in neurosurgical practice since the anterior and middle incisural spaces are often surgically exposed in neoplastic and vascular diseases. The high-definition pictures reported in this study could represent useful support to understand the anatomy of this complex region.Finally, our study could provide guidance to neurosurgical centers in which resources are limited that are either planning to establish their own cadaver dissection laboratory or failed to do so because of the supposed high-costs.

Tuberculum Sellae Meningioma: Report of Two Cases and Literature Review of Limits of the Transcranial and Endonasal Endoscopic Approaches

BACKGROUND

Tuberculum sellae (TS) meningioma is one of the most frequent meningiomas of the anterior skull base. Herein we perform a review of the literature concerning the preferred surgical approaches to TS meningiomas; in addition, we describe two explicative cases, operated on by our group using different approaches, with the aim to critically revise surgical indications and contraindications.

METHODS

In October 2021, two female patients with tuberculum sellae meningioma were treated at the Policlinico Gemelli of Rome. The patients presented with visual deterioration. Surgery was performed using the fronto-temporal approach and transsphenoidal approach. The visual function before and after surgery was evaluated as the main outcome parameter of the surgical treatment of these tumors.

CONCLUSIONS

Tuberculum sellae meningioma can be safely resected using the transcranial approach and the transsphenoidal endoscopic approach with preservation and even improvement of visual function after surgery. The relationship of the tumor with the optic nerves, optic canal, and anterior cerebral artery complex are important issues that have to be considered when dealing with tuberculum sellae meningioma. Both transcranial and endonasal approaches, in experienced hands, can allow complete resection of the lesion.

The Funnel: From the Skull Base to the Sacrum. New Trends and Technologies in Anaesthesia for the Adult Patient

The management of children affected by neurosurgical pathologies is multidisciplinary and should be set on several fronts.The potential need for massive blood components transfusions, the prolonged anaesthesia in paediatric age that may be often complicated by various forms of syndrome-related problems, and airway management are often encountered.The problems may be divided schematically into three large groups: preoperative, intraoperative and postoperative problems.The aim of this work is to optimize and make paediatric neurosurgery safe by highlighting the most important aspects in the various perioperative phases.

Multilevel Corpectomy for Subaxial Cervical Spondylodiscitis: Literature Review and Role of Navigation, Intraoperative Imaging and Augmented Reality

BACKGROUND

Subaxial cervical spine spondylodiscitis represents a real challenge in spine surgery. In later stages multiple spinal metamers can the interested by the pathological infection and the alteration of the spinal stability leading to spinal deformity. There is scant literature on subaxial cervical spondylodiscitis management and especially on ≥three-level cervical corpectomies. The authors conducted a literature search on this specific topic and presented an emblematic case of a patient treated with circumferential cervical fixation and four-level cervicothoracic corpectomy.

MATERIALS AND METHODS

A comprehensive literature review was performed using the combined Medical Subject Headings (MeSH) terms (multilevel) AND (sub axial spine OR cervical spine) AND (spine osteomyelitis OR spinal osteomyelitis), to search in the PubMed and Scopus databases. Our case was also included in this literature review. From our literature search the authors selected 13 papers, eight were excluded because they did not match our inclusion criteria (the involvement of only one or two levels, or did not perform corpectomy, discectomy, or cervical spine localization). The authors also presented a 71-year-old patient, in poor general clinical status who underwent several cage repositioning, with a final four-level corpectomy (C5, C6, C7, and T1), expandable C5-T1 cage positioning and C4-T2 anterior plating performed merging augmented reality, neuronavigation and intraoperative imaging.

RESULTS

This systematic review included 28 patients treated with ≥ three-level corpectomy (11 patients with three-level corpectomy, 15 patients with four-level corpectomy, and 2 patients with six-level corpectomy), 6 women, 5 men, and 17 not reported specifically, with a mean age of 55.9 years (range: 44-72 years). The combined anterior and posterior approach was taken in all but one case, which was treated with the anterior approach only. In one case of six-level cervicothoracic corpectomy, sternotomy was necessary. All reported patients recovered after surgery, except one who died after nosocomial pneumonia. No major intraoperative complications were reported. Usual postoperative complications include wound hematoma, pneumonia, subsidence, epidural hematoma, dural leakage, dysphagia, soft tissue swelling. The mean follow-up time was 31.9 months (range: 8-110 months).

CONCLUSION

According to the literature search performed by the authors, multilevel corpectomies for cervical spinal osteomyelitis is a safe and effective complex surgical procedure, even in extended procedures involving up to six levels or those at the cervicothoracic junction. The use multimodal navigation merging intraoperative imaging acquisition, navigation, and augmented reality may provide useful information during implant positioning in complex and altered anatomy and for assessing the best final result.

Spinal Dural Arteriovenous Fistulas: A Retrospective Analysis of Prognostic Factors and Long-Term Clinical Outcomes in the Light of the Recent Diagnostic and Technical Refinements

Spinal dural arteriovenous fistulas (dAVFs) are abnormal connections between the meningeal branches of segmental arteries and a radiculomedullary veins that result in a progressive myelopathy thanks to perimedullary coronal venous plexus congestion. Usually, dAVFs show nonspecific symptoms, thus leading to late clinical suspicion and a difficult MRI diagnosis.Several authors have tried to identify prognostic factors before treatment, but published studies results are often inconsistent and sometimes contradictory.In this study, we reviewed our recent experience of 30 dAVF patients where we collected all demographic, clinical and angioarchitectural features as well as radiological and treatment-related characteristics. The thoracic spine was the most common location, constituting 53.3% of cases, followed by the lumbar roots, comprising 30%. About 83% of patients showed motor deficits, urinary disturbances were present in 70%, and bowel symptoms in 50%.We treated 86.7% of patients with microsurgery and 13.3% with endovascular occlusion with a mean interval between clinical onset and intervention of 10.8 ± 14.2 months.A significant clinical improvement was observed at follow-up in 80% of patients, with a significant reduction in mean G-score, U-score and F-score at a mean follow-up of 105.89 ± 191.9 months.However, none among the principal demographic, clinical and radiological characteristics showed significant prognostic value to the clinical improvement observed at follow-up.

Spontaneous Intracranial Hypotension: Controversies in Treatment

Spontaneous intracranial hypotension (SIH) is a disorder of low cerebrospinal fluid (CSF) volume secondary to CSF leakage through a dural defect along the neuraxis with an estimated incidence of 5 people per 100,000.Great debate persists on the optimal treatment of this pathology, and clinical results are often contradictory. SIH may be initially approached via conservative measures, such as bed rest that is often supplemented with hydration, caffeine, and theophylline, which overall relieve symptoms in a small subset of patients at 6 months. Epidural blood patching (EBP) is generally the next consideration in symptom management. It is the most commonly performed intervention for spinal CSF leaks, as the first option or following the failure of conservative treatment. Further procedures may be performed in the case of EBP partial or temporary response and if the spinal CSF leak has been definitively localized (Beck et al., Neurology 87:1220-26, 2016). In those cases, if the CSF leak is well localized, the surgical closure of the spinal CSF leak may be considered.SIH is a complex but treatable CSF disorder. Despite recent advances in the field of neuroimaging and the different therapeutic options available, the appropriate management remains controversial and should be tailored to the patient.

Post-mortem Imaging of Brain/Spine Injuries: The Importance of a Comprehensive Forensic Approach

In forensic investigations, the limitations of the traditional purely autoptic approach can be overcome through post-mortem imaging (virtopsy). Virtospy has several applications to the investigation of brain and spinal injuries, whose analysis can be of forensic interest, especially in cases of suspected malpractice. In this scoping review, we briefly describe the main applications of the two most common post-mortem radiological techniques (computed tomography (CT) and magnetic resonance imaging (MRI)) to the forensic investigation of brain and spinal injuries in cases of medical malpractice or traumatic (accidental/homicidal/suicidal) deaths. Although CT represents the traditional approach to post-mortem imaging, MRI is proving to be a valuable tool to investigate brain and spinal injuries and lesions. These post-mortem radiological techniques can also be used to guide the surgeons in simulated surgical procedures on corpses in the context of training programs, thus helping operators to improve technical and non-technical skills and to reduce the risk of avoidable errors.

Pedicle Screw Placement Aided by C-Arm Fluoroscopy: A "Nevermore without" Technology to Pursue Optimal Spine Fixation

The surgical technique and the intraoperative technology that support spinal pedicle screw placement have consistently evolved over the past decades to decrease the misplacement rate of pedicle screws. We retrospectively evaluated our case series by analyzing the period 2016-2020. Patients undergoing pedicle screw fixation for cervical, thoracic, or lumbar spine degenerative diseases have been included. Surgery was carried out with the aid of intraoperative 3D C-arm fluoroscopy to assess and optimize screw placement and/or correct possible mispositioning. Each patient underwent a postoperative CT scan. Our aim was to evaluate the safety and accuracy of pedicle screw placement and estimate the variation in mispositioning rates. We carried out 329 surgical procedures, as follows: 70 cervical, 78 thoracic spine, and 181 lumbar spine surgeries. An excellent overall pedicle screw positioning was obtained, with slight differences between the cervical (98.6%), thoracic (100%), and lumbar (98.9%) tracts. Accordingly, only three patients required a revision surgery owing to mispositioning (0.91%). In particular, intraoperative C-arm fluoroscopy significatively improved the accuracy of thoracic screw positioning, as shown by postoperative CT scans. Our experience proves the crucial role of intraoperative C-arm fluoroscopy in pursuing optimal technical results and improving patient outcomes at follow-up.

Rheumatoid Diseases Involving the Cervical Spine I. History, Definition, and Diagnosis: New Trends and Technologies

The cervical spine might be involved in several conditions: congenital, traumatic, and chronic inflammatory and or degenerative rheumatic disorders. Among the inflammatory rheumatic conditions that can affect the cervical spine, rheumatoid arthritis (RA) is the most common, affecting up to 86% of patients and leading to cervical spine instability and subsequent myelopathy. Other inflammatory diseases include juvenile idiopathic arthritis (JIA) and the spondyloarthritis group (SpA), including psoriatic arthritis. Since many patients do not show symptoms of cervical involvement, diagnosis is often delayed. Radiographs are the first line imaging modality used to detect such involvement, but MRI and CT are superior in terms of early diagnosis and surgical planning.In this review, we provide an overview of cervical involvement in RA, JIA, and SpA.

Costotransversectomy in the Surgical Treatment of Mediolateral Thoracic Disk Herniations: Long-Term Results and Recent Minimally Invasive Technical Adjuncts

Thoracic herniated disks are relatively rare. They account for approximately 2% of all intervertebral herniated disks in large series. Traditional surgery via laminectomy has frequently yielded disappointing results, although the recent literature reports that anterior calcified thoracic herniation was successfully treated with this approach. This issue has encouraged a search for alternatives, such as anterolateral, lateral, and posterolateral approaches to the thoracic spine. From January 2009 to December 2019, we selected 66 patients harboring a symptomatic median-paramedian herniated disk at the level of the thoracic spine, treated at the authors' institutions. The present experience would give further support to the use of costotrasversectomy, along with its "mini-invasive" modifications, as a suitable and safe approach for thoracic disk disease. Although we must admit that endoscopy is likely to become the gold standard of surgical method in the future and that the anterior approach with mini-toracotomy without rib removal will become popular, the future scenario could certainly reserve an important place for the approach we have used in the surgical management of this challenging spinal pathology, mainly because of the approach's versatility and short learning curve.

Use of BoneScalpel Ultrasonic Bone Dissector in Anterior Clinoidectomy and Posterior Fossa Surgery: Technical Note

BackgroundFirst popularized by Dolenc, anterior clinoidectomies were performed with rongeurs, before the adoption of modern high-speed drills. We describe a novel application of the piezoelectric BoneScalpel™ in anterior skull base and posterior fossa surgeries. In the literature, to date, there are no mentions of anterior clinoidectomies performed with piezosurgical devices.MethodsWe reported a total of 12 patients, 8 affected by posterior fossa tumors and 4 treated for anterior skull base oncologic and vascular pathologies. This study aims to assess the safety and efficacy of the piezoelectric osteotomy in skull base and posterior fossa surgeries. In all patients, an ultrasonic bone dissector (BoneScalpel™ - Misonix) was used to perform the anterior clinoidectomy (AC) and craniotomy.ResultsA successful clinoidectomy was performed in 4 out of 12 patients (33.3%). We did not notice any heat damage to the surrounding soft tissue in critical areas such as paraclinoid structures. We documented only one durotomy in an oncologic patient, while no lesions of SSS or TS were detected.We recorded only a slightly increased surgery duration in the PIEZOSURGERY® and BoneScalpel™ group, compared to standard surgery with an osteotome to perform craniotomies, but no time difference in performing the clinoidectomy between BoneScalpel™ and a conventional high-speed drill.ConclusionWe report the first experience with piezosurgery for anterior clinoidectomy. There is no time difference in performing the clinoidectomy between BoneScalpel™ and a conventional high-speed drill, and this is an undoubted advantage in critical contexts such as clinoid-paraclinoid surgeries, where the risk of dural sinuses tears is common.

Pediatric Meningiomas: Current Insights on Pathogenesis and Management

Meningiomas are rare tumors in children, ranging from 0.4 to 4% of intracranial tumors. Differently from their adult counterpart, pediatric meningiomas (PMs) often show peculiar aspects such as the development of tumoral cysts, the involvement of the intraventricular space, and missing attachment to the dura mater. The most important difference with adults is represented by the high incidence of WHO grade II and III variants, which can account for more than 70% of cases. The prognosis of PMs mainly depends on the initial surgical resection because radiotherapy, which is the main treatment option in the case of tumor recurrence or progression, does not seem to increase the relapse free survival and the overall survival, and chemotherapy still misses specific and effective protocols.On these grounds, the need to better understand these tumors, to favor an appropriate multidisciplinary management, is particularly felt. The present review is focused on the advances on the pathogenesis, the molecular aspects, and the managements of PMs, with the goal to improve the knowledge of these challenging neoplasms.

New Trends in Neurosurgery: Toward a Future of Integration and Equity Among Male and Female Neurosurgeons

The gradual rise of women in medical schools and residencies, surpassing men in medical school applications, contrasts with the male dominance in surgical fields, including neurosurgery (only 18% women). Reasons include concerns about work-life balance, traditional childcare roles, and gender biases. In response, Women in Neurosurgery (WINs) was founded in 1989 to address gender disparities. However, WINs sessions at conferences evolved into segregated scientific sessions, deviating from their original purpose. This contradicts the ideal of a unified neurosurgical community. While some support segregated spaces, many advocate against gender-based divisions. Today WINs' existence is deemed outdated, with a call for integration, inclusivity, and equality in the modern era of neurosurgery.

Middle Meningeal Artery Embolization for the Management of Chronic Subdural Hematomas: A New-Old Treatment

Chronic subdural hematoma (cSDH) is defined as a subdural collection of blood on CT imaging that tends to persist and gradually increase in volume over time, with components that are hypodense or isodense compared to the brain. There are no proven guidelines for the management of patients with cSDH. Surgical approaches included burr hole, twist drill hole, and craniotomy-based evacuations. Outcomes after surgical removal is generally favorable, but cSDH tends to recur after the initial evacuation.Middle meningeal artery (MMA) embolization has been gaining increasing popularity among the treatments of cSDH. This is largely due to a growing population of patients with cSDH who are refractory to other treatments or in patients who present with multiple comorbidities or who are taking antiplatelet and anticoagulant medications. The goal of middle meningeal artery (MMA) embolization is to devascularize subdural membranes associated with SDH so that the balance between continued leakage and reabsorption is shifted toward reabsorption.We discuss our clinical and technical approach to cSDH treated with perioperative embolization of the MMA.

Posterior Surgical Ligation and Cyst Decompression -via Needle Puncture- of a Large Anterior Sacral Pelvic Meningocele Through Posterior Sacral Laminectomy

The first documented description of an anterior sacral meningocele was Bryant's in 1823. Anterior sacral meningocele patients have constipation as a universal symptom; urinary incontinence is also common. All the symptoms are directly related to the pressure from a pelvic mass on adjacent structures. When the patient stands, a headache often develops because the spinal fluid pressure decreases as the meningocele sac fills. Finally, a scimitar-shaped sacrum on a neuroradiological anteroposterior plain assessment is pathognomonic. The coccyx may be absent, and the lower sacral laminae may be absent or incomplete. The surgical options for this rare clinical condition are still matter of debate.Anterior sacral meningocele is a pathology that lacks a current classification and neurosurgical therapeutic standards, even though a similar dynamic has been shown by the related traumatic pseudomeningocele. Anterior approaches (retro- and transperitoneal meningocele neck occlusion with internal cerebrospinal fluid (CSF) cyst drainage) and posterior approaches (posterior sacral laminectomy, dural sac ligation, and CSF cyst drainage) are the available surgical strategies.We now report the case of an adult patient for whom a posterior approach was suggested and performed and report her postoperative surgical follow-up. The surgical rationale is also discussed.

Methods and Principles of the Intraoperative Neurophysiologic Monitoring in Neurosurgery

Intraoperative neurophysiologic monitoring (IONM) is an innovation introduced in neurosurgery in the past decades. It aims to support and guide the neurosurgeon to obtain the best surgical result possible, preventing the occurrence of neurological deficits. The somatosensory evoked potentials (SSEP) assess the integrity of the sensory pathways monitoring the dorsal column-medial lemniscus pathway during spine and cerebral surgery. Motor evoked potentials (MEPs) provide information on the integrity of the motor pathway monitoring the efferent motor pathways from the motor cortex to the muscle through corticospinal (or corticobulbar) tracts. Free-running EMG is the standard technique to monitor peripheral nerves, roots, or cranial motor nerves during surgery. Intraoperative EMG signals are activated during cranial motor nerves damaging or after an irritative stimulus. The duration, morphology, and persistence of EMG reflects the severity of neural injury. Nerve mapping consists of recording muscle activations given by direct nerve stimulation. This technique makes use of a stimulation probe available to the neurosurgeon which allows administering current directly to the nervous tissue (nerves, roots, etc.). Intraoperative neurophysiological monitoring (IONM) represents the standard of care during many procedures, including spinal, intracranial, and vascular surgeries, where there is a risk of neurological damage. Close communication and collaboration between the surgical team, neurophysiologist, and anesthesiologist is mandatory to obtain high-quality neuromonitoring, thus preventing neurologic injuries and gaining the best surgical "safe" results.

Lateral Approach to the Cervical Spine to Manage Degenerative Cervical Myelopathy and Radiculopathy

BACKGROUND

The cervical lateral approach can enlarge the spinal canal and foramen to achieve an effective neural decompression without needing spine stabilization. For this review, the authors' main objective was to illustrate the rationale, advantages, disadvantages, complications, and pitfalls of this technique, highlighting also areas for future development.

MATERIALS AND METHODS

A Medline via PubMed database search was carried out by using both keywords, namely "cervical oblique corpectomy," "multilevel oblique corpectomy and foraminotomy," and "lateral vertebrectomy," and Medical Subject Headings (MeSH) terms from 1 January 1991, up to 31 December 2021.

RESULTS

The analyzed articles suggested that the use of such a technique has declined over time; only 29 clinical studies met all the inclusion criteria and were retained for data analysis, including 1200 patients undergoing such an approach for the management of degenerative cervical myelopathies (DCMs) or of radiculopathies. The main etiopathogeneses were cervical stenosis, degenerative disk disease, or a mix of them-78% of which had a favorable outcome; the most frequent complications were transient and permanent Horner syndrome in 13.6% and 9.2% of cases, respectively. Long-term stability was reported in 97% of patients.

CONCLUSION

Multilevel cervical oblique vertebrectomy and/or lateral foraminotomy allow wide neural structure decompression and optimal stability given that the physiological spinal motion is preserved.

Combined Transoral Exoscope and OARM-Assisted Approach for Craniovertebral Junction Surgery. New Trends in an Old-Fashioned Approach

BACKGROUND

The introduction of recent innovations in the field of intraoperative imaging and neuronavigation, such as the O-arm StealthStation, allows for obtaining crucial intraoperative data by performing safer and controlled surgical procedures. As part of the improvement of surgical visual magnification and wide expansion of surgical corridors, the 3D 4 K exoscope (EX) has nowadays become an interesting and useful tool. The transoral approach (TOA) is the historical gold-standard direct microsurgical route to ventral craniovertebral junction (CVJ).

METHODS

We herein report our experience, consisting of ten cases via TOA concerning the simultaneous application of an O-arm with a StealthStation navigation system (Medtronic, Memphis, TN) and an imaging system, along with the 3D 4 K exoscopes in the TOA, for the treatment of CVJ pathologies.

RESULTS

No intraoperative neurophysiological changes or postoperative infections occurred, but neurological improvement was evident in all the patients. A complete decompression and a stable instrumentation and fusion of the CVJ were accomplished in all cases at the maximum follow-up time.

CONCLUSIONS

With EX, the role of the surgeon becomes self-sufficient with better individual surgical freedom compared to endoscopic surgery and excellent 3D vision and magnification. O-arms offer absolutely reliable intraoperative support for more-effective CVJ decompression. Nevertheless, with O-arm-assisted neuronavigation, it can be difficult to navigate C1 lateral masses and C2 isthmi, and converting 3D into 2D real-time navigation can be quite complicated. Finally, the combination of an EX with an O-arm appears more time-consuming compared to the old-fashion one.

Comparison Between Ventricular and Spinal Infusion Tests in Suspected Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is an often-overlooked or misdiagnosed brain disorder characterized by overt ventriculomegaly and associated with gait disturbances, cognitive impairment, and urinary incontinence. If correctly diagnosed, it is considered the only form of dementia treatable with surgery, namely through a ventriculoperitoneal or ventriculoatrial shunt with programmable valves.Among the 856 spinal and ventricular infusion tests performed from 2001 to 2017 at our institution, we analyzed 106 cases selected for suspected normotensive hydrocephalus. In all cases, Intracranial Elastance Index (IEI) and outflow resistance (Rout) values were calculated: 52 of these patients underwent Spinal Katzman Test (SKT), and the remaining 54 underwent an intraventricular infusion test (IVKT). Of the 40 patients in the SKT group with pathological elastance (71%), 17 also had a Rout >12 mmHg and 23 a Rout <12 mmHg. Of the 50 patients in the IVKT group with pathological elastance (92%), 38 also had a Rout >12 mmHg and 12 a Rout <12 mmHg.IVKT and SKT to date represent two useful tools in the diagnosis of normal pressure hydrocephalus. Despite being more invasive, IVKT, including both the intracranial elastance index (IEI) and Rout analysis, could be considered more reliable than SKT and therefore could be reserved for the most controversial cases.

Atlantoaxial Anterior Transarticular Screw Fixation: Indications and Surgical Technique

Posterior atlantoaxial screw fixation is a widely adopted therapeutic option for C1-C2 instability secondary to fractures or dislocation, degenerative diseases, or tumors at this level. Anterior transarticular screw fixation (ATSF) is an effective alternative to the posterior approaches, presenting several advantages despite being scarcely known and rarely chosen.In this chapter, we describe the ATSF step by step, illustrating its variations reported in literature, and we critically analyze the several advantages and contraindications of this technique. Moreover, we provide a list of tips and tricks on the surgical procedure, including critical operating room settings-the result of more than 10 years of experience in the field by a senior author.ATSF is a valid strategy for the treatment of different diseases occurring at the level of the atlantoaxial complex that needs consideration. Given the significant learning curve of this strategy, some hints may be essential to begin introducing this technique in the personal armamentarium of a spine surgeon so that they can perform ATSF safely and effectively.

New Trend in Craniovertebral Junction Surgical Strategy: Technical Note for the Treatment of Hangman's Fractures Through a Minimally Invasive Approach

INTRODUCTION

The reduction, stabilization, and maintenance of alignment are the main goals in the surgical treatment of unstable hangman's fractures. The choice of the surgical strategy remains poorly standardized; anterior and/or posterior fusion could be performed; and none of the available clinical studies in the literature have shown significant differences in outcomes or complication rates. Vertebral anatomy, age, comorbidities, patient factors, and surgical experience may guide the treatment choice.

METHODS

We present a case of a polytraumatized young woman with an unstable hangman's fracture type II, according to Levine-Edwards classification. We treated the fracture by using a plate with four holes to fix C2-C3 without discectomy and body fusion.

RESULTS

We performed a small incision, such as those used for the fixation of odontoid screws, where the working angle allowed us to easily and quickly position the plate by using a minimally invasive approach.

CONCLUSION

The stabilization alone, without discectomy and body fusion with the cage, in the same way favored the natural healing of the bone fracture. In our opinion, in some select cases, fixation of C2-C3 alone through a minimally invasive approach allows for bone healing with fewer risks and an easier surgery.

Spinal Epidural Atypical Meningioma: Case Report and Review of the Literature

Spinal atypical meningiomas are rare, and those whose main extension is in the epidural space are anecdotal. Here, we report a case of a young woman presenting with sensory disturbances and a radiological diagnosis of a dorsal epidural sleeve-like mass. The surgical resection of the lesion allowed the decompression of the spinal cord and led to the histopathological diagnosis of atypical meningioma. At the 3-month follow-up, her neurological recovery was complete. Because of the gross total removal of the lesion, adjuvant radiotherapy was not performed: At the 2-year follow-up, no recurrence of disease was detected. A comprehensive literature review was performed, and just two more case reports on epidural atypical meningiomas were found in the English literature. Through this case report and literature review, we described a rare manifestation of spinal meningioma that entered into a differential diagnosis for extradural spinal lesions, such as secondary malignancies.

Does Laminectomy Affect Spino-Pelvic Balance in Lumbar Spinal Stenosis? A Study Based on the EOS X-Ray Imaging System

PURPOSE

Lumbar spinal stenosis (LSS) is a degenerative disorder causing the forward bending of the trunk and pelvic retroversion with the consequent loss of lumbar lordosis; surgical treatment is intended to enlarge the canal and foramina and decompress the nerve roots. The purpose of our study is to determine whether and to what extent facet-sparing laminectomy affects the spino-pelvic balance.

METHODS

The spino-pelvic balance of 26 patients was analysed before and after surgery through the EOS X-ray Imaging System. The following parameters were considered: thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). Clinical data were expressed in numeric values according to the Oswestry Disability Index (ODI), the visual analogue scale (VAS) and the modified Japanese Orthopaedic Association (mJOA) scoring system.

RESULTS

Significant SS decreases and PT increases were noticed after surgery, without modification in LL, axial vertebral rotation (AVR) and the general alignment. Pain and disability had a significant improvement, as represented by a decrease in scores on the VAS and ODI scales and an increase in scores on the mJOA functional scale.

CONCLUSION

The most important parameter seems to be a congruence between pelvic and spinal parameters, which achieves an economic posture with the physiologic position of the axis of gravity. According to the literature, a standard sagittal balance (SB) has not been defined.

Working in low- and middle-income countries: Learning from each other

•Barriers may limit LMICs-HICs collaborations: infrastructure, equipment's lack/inadequacy, political issues, brain drain.•Local training is crucial for universal health coverage; several activities are headed by Global Neurosurgery organisations.•The ​EANS Global and Humanitarian Neurosurgery Committee aims to become a gateway for partnerships between HICs and LMICs.

Surgical Treatment of Diffuse Idiopathic Skeletal Hyperostosis (DISH) Involving the Cervical Spine: Technical Nuances and Outcome of a Multicenter Experience

STUDY DESIGN

Retrospective multicenter.

OBJECTIVES

diffuse idiopathic skeletal hyperostosis (DISH) involving the cervical spine is a rare condition determining disabling aero-digestive symptoms. We analyzed impact of preoperative settings and intraoperative techniques on outcome of patients undergoing surgery for DISH.

METHODS

Patients with DISH needing for anterior cervical osteophytectomy were collected. Swallow studies and endoscopy supported imaging in targeting bone decompression. Patients characteristics, clinico-radiological presentation, outcome and surgical strategies were recorded. Impact on clinical outcome of duration and time to surgery and different surgical techniques was evaluated through ANOVA.

RESULTS

24 patients underwent surgery. No correlation was noted between specific spinal levels affected by DISH and severity of pre-operative dysphagia. A trend toward a full clinical improvement was noted preferring the chisel (P = 0.12) to the burr (P = 0.65), and whenever C2-C3 was decompressed, whether hyperostosis included that level (P = 0.15). Use of curved chisel reduced the surgical times (P = 0.02) and, together with the nasogastric tube, the risk of complications, while bone removal involving 3 levels or more (P = 0.04) and shorter waiting times for surgery (P < 0.001) positively influenced a complete swallowing recovery. Early decompressions were preferred, resulting in 66.6% of patients reporting disappearance of symptoms within 7 days. One and two recurrences respectively at clinical and radiological follow-up were registered 18-30 months after surgery.

CONCLUSION

The "age of DISH" counts more than patients' age with timeliness of decompression being crucial in determining clinical outcome even with a preoperative mild dysphagia. Targeted bone resections could be reasonable in elderly patients, while in younger ones more extended decompressions should be preferred.

Atlantoaxial Joint Distraction and Fusion with DTRAX Intra-Articular Cages: A Cadaveric Feasibility Study and Review of the Pertinent Literature

PURPOSE

Atlantoaxial joint distraction is a key procedure for the treatment of selected patients affected by basilar invagination (BI). In recent years, several authors have reported various techniques of distraction and fixation of the C1-C2 joint using different types of intra-articular spacers, with or without posterior fixation. We review the pertinent literature and propose a feasibility study on the use of a new device for the distraction of the C1-C2 joint aimed to the descent of the dens out of the foramen magnum suggesting its application on selected cases of BI.

METHODS

The GL-DTRAX Cervical Cage-SE is a cage approved by the Food and Drug Administration for distraction and fixation of subaxial cervical spine. Five adult cadaveric specimens were dissected surgically to evaluate the feasibility of DTRAX insertion inside the C1-C2 joint through a posterior approach.

RESULTS

The cages were uneventfully set into the C1-C2 intra-articular space of all samples without the need to sacrifice C2 nerve roots and ganglia. Postoperative cervical computed tomography scanning confirmed the correct fitting of the devices in every sample.

CONCLUSIONS

This cadaveric study highlights the feasibility of the DTRAX cage as a C1-C2 intra-articular device producing a substantial distraction of atlantoaxial complex and suggesting a possible therapeutic role in selected cases of BI.