Use of cranial fixation pins in pediatric neurosurgery

Feasibility and safety of stereoelectroencephalography in young children

PURPOSE

Stereoelectroencephalography (SEEG) is a diagnostic surgery that implants electrodes to identify areas of epileptic onset in patients with drug-resistant epilepsy (DRE). SEEG is effective in identifying the epileptic zone; however, placement of electrodes in very young children has been considered contraindicated due to skull thinness. The goal of this study was to evaluate if SEEG is safe and accurate in young children with thin skulls.

METHODS

Four children under the age of two years old with DRE underwent SEEG to locate the region of seizure onset. Presurgical planning and placement of electrodes were performed using ROSA One Brain. Preoperative electrode plans were merged with postoperative CT scans to determine accuracy. Euclidean distance between the planned and actual trajectories was calculated using a 3D coordinate system at both the entry and target points for each electrode.

RESULTS

Sixty-three electrodes were placed among four patients. Mean skull thickness at electrode entry sites was 2.34 mm. The mean difference between the planned and actual entry points was 1.12 mm, and the mean difference between the planned and actual target points was 1.73 mm. No significant correlation was observed between planned and actual target points and skull thickness (Pearson R =  - 0.170). No perioperative or postoperative complications were observed.

CONCLUSIONS

This study demonstrates that SEEG can be safe and accurate in children under two years of age despite thin skulls. SEEG should be considered for young children with DRE, and age and skull thickness are not definite contraindications to the surgery.

Safe First-Time use of Stereotactic Headband Fixation in a 5-Month-Old Child: An Economical and Easily Accessible Method

OBJECTIVE

We present a low-cost and easily accessible adaptation system to perform stereotactic procedures in infants.

METHODS

We used an adaptive device consisting of a headband with a plaster bandage, cotton bandage roll, and gauze bandages. Prior to its clinical application, the device was tested in our neuroscience laboratory using a simulation model of a size similar to that of a 5-month-old infant, during which no complications arose. The headband cast technique was subsequently reproduced in a 5-month-old patient, serving as a fixation point for the placement of a Micromar frame for biopsy of a thalamic lesion.

RESULTS

A stereotactic biopsy was successfully performed in a 5-month-old patient using a headband cast to secure the stereotactic frame. This method enabled precise targeting of the selected site, resulting in a histopathological diagnosis without any associated complications.

CONCLUSIONS

The adaptive device is safe, easily accessible, and reproducible, facilitating the performance of stereotactic diagnostic procedures in infants, accurately reaching the planned objective without causing injuries or additional complications.

Adaptable three-pin skull clamp for large animal research

Traditionally, surgical head immobilization for neurobiological research with large animals is achieved using stereotaxic frames. Despite their widespread use, these frames are bulky, expensive, and inflexible, ultimately limiting surgical access and preventing research groups from practicing surgical approaches used to treat humans. Here, we designed a mobile, low-cost, three-pin skull clamp for performing a variety of neurosurgical procedures on non-human primates. Modeled after skull clamps used to operate on humans, our system was designed with added adjustability to secure heads with small or irregular geometries for innovative surgical approaches. The system has six degrees of freedom with skull pins attached to setscrews for independent, fine-tuned depth adjustment. Unlike other conventional skull clamps which require additional mounting fixtures, our system has an integrated tray with mounting bracket for easy use on most operating room tables. Our system has successfully secured primate heads in the supine and lateral position, allowing surgeons to match surgical approaches currently practiced when operating on humans. The system also expands the opportunity for researchers to utilize imaged-guided robotic surgery techniques. Overall, we hope that our system can serve as an adaptable, affordable, and robust surgery platform for any laboratory performing neurobiological research with large animal models.

A novel technique for frame-based MR-guided laser ablation in an infant

Hypothalamic hamartomata (HH) not only are usually associated with drug-resistant epilepsy but can also cause precocious puberty and developmental delay. Gelastic seizures are the most common type of seizures. Magnetic resonance image (MRI)-guided laser interstitial thermal therapy (LiTT) is a technique whereby a laser fibre is stereotactically implanted into a target lesion and heat is used to ablate whilst tissue temperature is monitored using MRI thermography. MRI-guided LiTT has proven to be an effective and safe method to treat HH. To use the LiTT system, highly accurate stereotactic fibre implantation is required. This can be achieved by the use of frame-based or frameless neuronavigation techniques. However, these techniques generally involve rigid head immobilisation using cranial pin fixation. Patients need sufficient skull thickness to safely secure the pins and sufficient skull rigidity to prevent deformation. Hence, most of the clinical reports on the use of LiTT for children describe patients aged 2 years or older. We report a novel and practical technique of using a paste cast helmet to securely place a stereotactic frame in a 5-month-old infant with HH and drug-resistant epilepsy that allowed the successful application of MRI-guided LiTT.

Robotic external ventricular drain placement for acute neurosurgical care in low-resource settings: feasibility considerations and a prototype design

OBJECTIVE

Emergency neurosurgical care in lower-middle-income countries faces pronounced shortages in neurosurgical personnel and infrastructure. In instances of traumatic brain injury (TBI), hydrocephalus, and subarachnoid hemorrhage, the timely placement of external ventricular drains (EVDs) strongly dictates prognosis and can provide necessary stabilization before transfer to a higher-level center of care that has access to neurosurgery. Accordingly, the authors have developed an inexpensive and portable robotic navigation tool to allow surgeons who do not have explicit neurosurgical training to place EVDs. In this article, the authors aimed to highlight income disparities in neurosurgical care, evaluate access to CT imaging around the world, and introduce a novel, inexpensive robotic navigation tool for EVD placement.

METHODS

By combining the worldwide distribution of neurosurgeons, CT scanners, and gross domestic product with the incidence of TBI, meningitis, and hydrocephalus, the authors identified regions and countries where development of an inexpensive, passive robotic navigation system would be most beneficial and feasible. A prototype of the robotic navigation system was constructed using encoders, 3D-printed components, machined parts, and a printed circuit board.

RESULTS

Global analysis showed Montenegro, Antigua and Barbuda, and Seychelles to be primary candidates for implementation and feasibility testing of the novel robotic navigation system. To validate the feasibility of the system for further development, its performance was analyzed through an accuracy study resulting in accuracy and repeatability within 1.53 ± 2.50 mm (mean ± 2 × SD, 95% CI).

CONCLUSIONS

By considering regions of the world that have a shortage of neurosurgeons and a high incidence of EVD placement, the authors were able to provide an analysis of where to prioritize the development of a robotic navigation system. Subsequently, a proof-of-principle prototype has been provided, with sufficient accuracy to target the ventricles for EVD placement.

The Hybrid Operative Suite with Intraoperative Biplane Rotational Angiography in Pediatric Cerebrovascular Neurosurgery: Utility and Lessons Learned

INTRODUCTION

The benefits of performing open and endovascular procedures in a hybrid neuroangiography surgical suite include confirmation of treatment results and reduction in number of procedures, leading to improved efficiency of care. Combined procedural suites are infrequently used in pediatric facilities due to technical and logistical limitations. We report the safety, utility, and lessons learned from a single-institution experience using a hybrid suite equipped with biplane rotational digital subtraction angiography and pan-surgical capabilities.

METHODS

We conducted a retrospective review of consecutive cases performed at our institution that utilized the hybrid neuroangiography surgical suite from February 2020 to August 2021. Demographics, surgical metrics, and imaging results were collected from the electronic medical record. Outcomes, interventions, and nuances for optimizing preoperative/intraoperative setup and postoperative care were presented.

RESULTS

Eighteen procedures were performed in 17 patients (mean age 13.4 years, range 6-19). Cases included 14 arteriovenous malformations (AVM; 85.7% ruptured), one dural arteriovenous fistula, one mycotic aneurysm, and one hemangioblastoma. The average operative time was 416 min (range 321-745). There were no intraoperative or postoperative complications. All patients were alive at follow-up (range 0.1-14.7 months). Five patients had anticipated postoperative deficits arising from their hemorrhage, and 12 returned to baseline neurological status. Four illustrative cases demonstrating specific, unique applications of the hybrid angiography suite are presented.

CONCLUSION

The hybrid neuroangiography surgical suite is a safe option for pediatric cerebrovascular pathologies requiring combined surgical and endovascular intervention. Hybrid cases can be completed within the same anesthesia session and reduce the need for return to the operating room for resection or surveillance angiography. High-quality intraoperative angiography enables diagnostic confirmation under a single procedure, mitigating risk of morbidity and accelerating recovery. Effective multidisciplinary planning enables preoperative angiograms to be completed to inform the operative plan immediately prior to definitive resection.

The Incidence of Depressed Skull Fractures Due to the Use of Pin-Type Head Frame Systems in the Adult Population: 10-year Experience of a Single Neurosurgical Center

OBJECTIVE

Pin-type head frame systems have become a worldwide standard procedure, but they can cause some complications on rare occasions. This study aimed to examine the incidence and associated risk factors of depressed skull fracture and related intracranial hematoma (DSFH) due to the use of head frames in our institute over the past 10 years.

METHODS

This study included 1749 patients who underwent neurosurgical surgeries using pin-type head frames, including the Mayfield (Integra NeuroSciences, Plainsboro, NJ) skull clamp (721 cases) and the Sugita (Mizuho Ikakogyo Co., Ltd., Tokyo, Japan) head frame (1028 cases). We retrospectively reviewed hospital records of our institute to identify cases of DSFH, and documented the type of head frame used, as well as patient characteristics.

RESULTS

The incidence of DSFH was 0.29% (5 of 1749 cases). All 5 cases had an associated epidural hematoma, with a single case having an additional dural laceration (without subdural damage). All perforation sites, located at the parietal bone near the pterion, occurred by the unilateral horizontal screw of the Sugita head frame. None of the patients experienced postoperative neurological decline.

CONCLUSIONS

Even in the adult population, the DSFH by the pin-type head frame can occur infrequently. Based on our results, we recommend that the following factors should be considered when the pin-type head frame is used for neurosurgical procedures: location of pin application, thickness and fragility of the skull, and adequate control of compressive forces exerted by the head frame.

The Mayfield Skull Clamp: A Literature Review of Its Complications and Technical Nuances for Application

BACKGROUND

The Mayfield skull clamp is the most commonly used 3-pin head immobilization device. It is routinely used in cranial neurosurgical procedures and selected cervical procedures. Despite its role in some serious complications, guidelines and nuances on the correct application of the Mayfield clamp are lacking. The goal of this article was to present an overview of the complications associated with the Mayfield skull clamp. We also present a conceptual framework of the correct use-in our opinion-of the Mayfield clamp in several standard approaches to avoid the most common complications.

METHODS

PubMed was searched for original articles published between 1980 and 2020 with the search terms "Mayfield skull clamp" and "Mayfield head clamp." Eligibility criteria were availability of English abstract and complications clearly attributed to the Mayfield skull clamp. Both authors assessed all search results for eligibility. Additional articles were found with cross-references.

RESULTS

The most common complications associated with Mayfield clamp application were due to vascular injury inflicted by the pins or skull fractures. Complications related to use of the Mayfield clamp were rare but often serious and avoidable. A conceptual framework was presented on how to avoid these complications.

CONCLUSIONS

Attention to detail, anatomy, and the primum non nocere principle are imperative in every step of the neurosurgical pathway, including placement of the Mayfield skull clamp. Thoughtful application, taking into consideration several nuances, is recommended to avoid inadvertent patient harm.

Potential risk analysis and experience summarization of unstable factors of cranial fixation devices in neurosurgical operations: three-case reports and systematic review

Background

The use of cranial fixation devices in neurosurgery is very common, which is considered to be an important auxiliary method for many craniotomies. However, previous studies have reported complications of using cranial fixation devices, including brain tissue, nerve and blood vessel damage, scalp laceration, subcutaneous hematoma, etc. Some of the complications are serious and even potentially fatal, and the causes of which may be related to the incorrect use of cranial fixation devices. Although there are no serious complications in our review, the cause of that needs to be further summarized and analyzed, as so to minimize the serious consequences caused by the cranial fixation device slippage and ensure the safety of the patients’ surgical procedure.

Case presentation

In our recent work, we have continuously found three cases of unstable cranial fixation devices, which make us to analyze the possible factors and summarize experience combined with the review of other senior neurosurgeons (more than 3 years of working experience) from different departments of neurosurgery.

Conclusions

Based on our recent incidents of unstable cranial fixation and the experience of investigating and analyzing senior doctors from different neurosurgery centers, we summarized experience to minimize the risk of unstable cranial fixation. We tried a variety of options, including a safe anatomical location for cranial fixation, teamwork, and communication with anesthesiologists and itinerant nurses, to ensure the stability of the patient’s cranial fixation devices. The data obtained in this survey has great limitations, including the doctor’s personal prejudice and dependence on anecdotal memories. Therefore, the data should be interpreted with caution. However, there are still some modes that can help to better understand the use of safe cranial fixation. Based on the above research and analysis, we have made recommendations that may help neurosurgeons to avoid preventable complications

Skull fracture and epidural hematoma caused by use of a Mayfield skull clamp in an adult patient with chronic hemodialysis: a case report

BACKGROUND

Mayfield skull clamps are widely used and indispensable in current neurosurgery. Complications such as skull fractures or intracranial hematoma from using a Mayfield skull clamp have largely been reported in the pediatric population, are likely related to the relative thinness of the skull, such as in patients with hydrocephalus, and are extremely rare in adults. Here, we report a case of skull fracture and epidural hematoma caused by a Mayfield skull clamp used for posterior decompression surgery in an adult patient with chronic hemodialysis.

CASE PRESENTATION

A 67-year-old Asian male patient with a history of dialysis-dependent chronic renal failure over 36 years suffered from severe cervical myelopathy. Neurological examination and radiographic images revealed cervical spondylotic myelopathy due to dialysis-related spondyloarthropathy. Laminoplasty was planned on patient consent. A Mayfield skull clamp was applied with the patient supine. Torque was applied to the screws with gentle care, but there was no resistance and it was not easy to reach the standard 60 lb (267 N) to 80 lb (356 N). Because a skull fracture was suspected, we canceled the surgery. Emergency head computed tomography showed depressed skull fractures underlying the single-pin sites with an associated epidural hematoma. The fractures and epidural hematoma were treated conservatively, and spontaneous resolution of the hematoma was confirmed. Cervical laminoplasty was performed successfully using a mask-type head holder on the subsequent day.

CONCLUSIONS

As a precaution for fractures and epidural hematoma in neurosurgical patients with bone fragility or a thin skull, use of a mask-type fixing device or halo ring is recommended.

Respond of the different human cranial bones to pin-type head fixation device

Background

At this juncture, there is no consensus in the literature for the use and the safety of pin-type head holders in cranial procedures.

Methods

The present analysis of the bone response to the fixation of the instrument provides data to understand its impact on the entire skull as well as associated complications. An experimental study was conducted on fresh-frozen human specimens to analyze the puncture hole due to the fixation of each single pin of the pin-type head holder. Cone-beam CT images were acquired to measure the diameter of the puncture hole caused by the instrument according to several parameters: the pin angle, the clamping force, and different neurosurgical approaches most clinically used.

Results

The deepest hole, 2.67 ± 0.27 mm, was recorded for a 35° angle and a clamping force of 270 N at the middle fossa approach. The shallowest hole was 0.62 ± 0.22 mm for the 43° angle with a pinning force of 180 N in the pterional approach. The pterional approach had a significantly different effect on the depth of the puncture hole compared with the middle fossa craniotomy for 270 N pinning at 35° angle. The puncture hole measured with the 43° angle and 180 N force in prone position is significantly different from the other approaches with the same force.

Conclusions

These results could lead to recommendations about the use of the head holder depending on the patient’s history and cranial thickness to reduce complications associated with the pin-type head holder during clinical applications.

Pediatric Anesthesia Outside the Operating Room: Case Management

Anesthesiology teams care for children in diverse locations, including diagnostic and interventional radiology, gastroenterology and pulmonary endoscopy suites, radiation oncology units, and cardiac catheterization laboratories. To provide safe, high-quality care, anesthesiologists working in these environments must understand the unique environmental and perioperative considerations and risks involved with each remote location and patient population. Once these variables are addressed, anesthesia and procedural teams can coordinate to ensure that patients and families receive the same high-quality care that they have come to expect in the operating room. This article also describes some of the considerations for anesthetic care in outfield locations.

Pinning in pediatric neurosurgery: the modified rubber stopper technique

Head immobilization devices with skull pins are commonly used by neurosurgeons to stabilize the head for microsurgical techniques and to maintain accurate intraoperative neuronavigation. Pediatric patients, who may have open fontanelles, unfused sutures, and thin skulls, are vulnerable to complications during placement in pins. We review the various methods of pinning in pediatric neurosurgery and revisit the modified rubber stopper technique using a commonly available rubber stopper from a medication bottle over a standard adult pin of a Mayfield head clamp to prevent the pins from plunging through the thin pediatric skull.

Preoperative evaluation and surgical management of infants and toddlers with drug-resistant epilepsy

OBJECTIVE Despite perioperative risks, epilepsy surgery represents a legitimate curative or palliative treatment approach for children with drug-resistant epilepsy (DRE). Several factors characterizing infants and toddlers with DRE create unique challenges regarding optimal evaluation and management. Epilepsy surgery within children < 3 years of age has received moderate attention in the literature, including mainly case series and retrospective studies. This article presents a systematic literature review and explores multidisciplinary considerations for the preoperative evaluation and surgical management of infants and toddlers with DRE. METHODS The study team conducted a systematic literature review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, targeting studies that investigated children < 3 years of age undergoing surgical treatment of DRE. Using the PubMed database, investigators selected peer-reviewed articles that reported seizure outcomes with or without developmental outcomes and/or perioperative complications. Studies were eliminated based on the following exclusion criteria: sample size < 5 patients; and inclusion of patients > 3 years of age, when demographic and outcomes data could not be separated from the cohort of patients < 3 years of age. RESULTS The study team identified 20 studies published between January 1990 and May 2017 that satisfied eligibility criteria. All selected studies represented retrospective reviews, observational studies, and uncontrolled case series. The compiled group of studies incorporated 465 patients who underwent resective or disconnective surgery (18 studies, 444 patients) or vagus nerve stimulator insertion (2 studies, 21 patients). Patient age at surgery ranged between 28 days and 36 months, with a mean of 16.8 months (1.4 years). DISCUSSION The study team provided a detailed summary of the literature review, focusing on the etiologies, preoperative evaluation, surgical treatments, seizure and developmental outcomes, and potential for functional recovery of infants and toddlers with DRE. Additionally, the authors discussed special considerations in this vulnerable age group from the perspective of multiple disciplines. CONCLUSIONS While presenting notable challenges, pediatric epilepsy surgery within infants and toddlers (children < 3 years of age) offers significant opportunities for improved seizure frequency, neuro-cognitive development, and quality of life. Successful evaluation and treatment of young children with DRE requires special consideration of multiple aspects related to neurological and physiological immaturity and surgical morbidity.

A novel method for safe and accurate placement of the rocker pins of head immobilization devices utilizing a digital caliber phantom: technical note

BACKGROUND

Immobilization of the head and skull by head immobilization devices (HIDs) is a common practice in neurosurgery. A variety of complications and morbidities are associated with pinning the skull during application of HIDs.

OBJECTIVE

Our aim is to describe a new technique that avoids repeated puncturing of the head and skull during application of HIDs and hence avoiding the potential complications resulting from multiple re-adjustments.

METHODS

We used a pre-adjusted digital millimetric caliber (DMC) as a phantom for the two rocker pins of the HID to mimic and simulate the process of skull pinning. Localization and preparation of the accurate skull pinning sites are safely guided by the pinning phantom.

RESULTS

The technique was applied in different neurosurgical approaches. The pinning phantom was utilized to accurately locate the suitable pinning sites. Contrary to the common practice, there was no need for repeated head and skull puncturing. Minimal manipulations of the head and neck are exerted in this approach as compared with the usual techniques. The head of the patient is allowed to be kept safe on the operating table until the final one-time confident skull pinning by the sterilized skull clamp pins.

CONCLUSION

The process of scalp and skull pinning of HIDs is technically demanding. The DMC utilized as a pinning phantom is a useful technique which provides safe and confident application of the skull rocker pins of HIDs allowing the neurosurgeon to avoid multiple puncturing of scalp and skull and minimizing manipulations of the head and cervical spine.

Rigid Cranial Fixation for Robot-Assisted Stereoelectroencephalography in Toddlers: Technical Considerations

BACKGROUND

Stereoelectroencephalography (sEEG) using depth electrodes has become a mainstay of pediatric epilepsy surgery. This technique relies on rigid cranial fixation using skull pins, which forms the basis for accurate stereotactic navigation. The use of cranial fixation pins poses the threat of traumatic skull injuries in young children because of inadequate cranial bone thickness.

OBJECTIVE

To describe a rigid cranial fixation technique involving the integrated Gel Head Ring from the DORO QR3 multipurpose skull clamp set (Pro Med Instruments) with superimposed pin fixation in children below the age of 36 mo undergoing sEEG.

METHODS

Patients were placed in the supine position and the head was fixed using a DORO skull clamp with 3 pediatric cranial pins. The head was supported on the integrated Gel Head Ring, and a pin pressure of 20 pounds was applied. The DORO skull clamp set was then attached to the ROSA neurosurgical robot support telescopic arm for stereotactic navigation.

RESULTS

We present an illustrative series of 2 patients below the age of 3 yr with medically refractory epilepsy who underwent sEEG using our modified cranial fixation technique. Head position and reference registration were stable throughout the surgeries. Postoperative volumetric computed tomography scans of the head showed accurate placement of sEEG depth electrodes and did not reveal any fractures or epidural hematoma. No other complications related to cranial fixation were noted.

CONCLUSION

Concurrent use of rigid and nonrigid cranial fixation using the DORO skull clamp set provides safe and effective cranial fixation in infants and toddlers undergoing sEEG.

Bilateral skull fracture with massive epidural hematoma secondary to pin-type head fixation in a pediatric patient: Case report and review of the literature

INTRODUCTION

A head fixation device containing pins is common equipment used in neurosurgical procedures. Previous reports analysed some of the complications associated with the application of this device for adults and children, even the indications for the use in pediatric are not well defined.

CASE PRESENTATION

An 11-year-old girl diagnosed with non-communicating hydrocephalus, caused by posterior fossa tumor. During the surgery, complications were found in the form of acute epidural hematoma due to head fixation pins. So, the operation was stopped. Emergent CT scan was carried out and showed a bilateral skull fracture and a massive right-sided epidural hematoma. An emergency craniotomy for clot removal was performed and five days later, a second surgery was carried out uneventfully for the residual tumor. The patient fully recovered after the second surgery.

DISCUSSION

Complications due to the use of a pin head fixation are easier to occur in pediatric patients, because the bones are thinner and need more carefull strategy when pinning. With promp identification of any complications and earlier treatment, the good outcome will be achieved. We compared our case report with published literature in order to suggest the way to prevent this complication.

CONCLUSION

Skull fractures and associated epidural hematomas in pediatric patients need to be considered as possible complications of the pin-type head fixation application. The head fixation devices in pediatric need to be used with great caution and knowing the risk factors, safe technique for application and management of complications will prevent worse outcome.

The impact of intraoperative magnetic resonance in routine pediatric neurosurgical practice-a 6-year appraisal

BACKGROUND

The intraoperative magnetic resonance scanner (ioMR) was introduced in our unit in 2009, and has been used routinely since then.

OBJECTIVE

This study aims to describe indications, radiological features, and clinical outcomes of the patients operated on with ioMRI and analyze our experience.

METHODS

A retrospective analysis of a prospective surgical database has been performed, including surgical procedure, intent, radiological reports, need for second-look surgery, and complications, supplemented by further review of the clinical notes and the scans.

RESULTS

From 2009 to 2015, 255 surgical procedures with ioMR were performed: 175 were craniotomies for tumor excision, 65 were epilepsy related, and 15 were biopsies or cyst drainages. The mean age was 9.4 years. One ioMR was performed in 79.5% patients; the mean duration of the MR was 41 min. In 172 cases (67.4%), no actions followed the ioMR. When the aim of the surgery was debulking of the tumor, the percentage of patients in which the ioMR was followed by resection was higher than when complete resection was the aim (56 vs 27.5%). The complication rate was not increased when compared with our previous results (infection 1%, neurological deficits 12%).

CONCLUSION

This is the largest published series of ioMRI-aided pediatric neurosurgery to date. We have demonstrated that it can be used safely and routinely in pediatric neurosurgical procedures at any age, assisting the surgeon in achieving the best extent of resection and aiding in intra-operative decision-making for tumor- and non-tumor-related intracranial pathology.

Method to perform safety stereotactic procedures in children under 2 years of age

INTRODUCTION

Stereotactic procedures have been used in neurosurgery for many years. In children especially, care should be considered to avoid complication caused by fixation of the frame in a not fully developed skull bone. We present our method to adapt the frame in children under 2 years of age.

METHODS

Twelve procedures in patients under 24 months were performed between 2003 and 2015. Micromar frame was used. It was adapted with a small pillow made of gauss attached to the posterior part to hold the head, then four pins were fixed without adjustment. We analyze for each patient age, indication, histopathology, and complications.

RESULTS

Eleven patients with a mean age of 13.5 months (range 9 to 22 months) underwent 12 stereotactic procedures. In all cases, biopsy samples were obtained, histopathology was positive in 11/12 cases. No complications occurred.

CONCLUSION

Stereotactic frame procedures need special attention in small children where the skull bones are not fully developed. We present a simple method to perform this surgery in patients under 2 years of age.

Developmental Considerations in Pediatric Skull Base Surgery

Objectives  To review developmental surgical anatomy and technical nuances related to pediatric skull base surgery. Design  Retrospective, single-center case series with literature review. Setting  MD Anderson Cancer Center. Participants  Patients undergoing pediatric skull base surgery. Main Outcome Measures  Review developmental anatomy of the pediatric skull base as it relates to technical nuance of various surgical approaches and insight gained from a 25-year institutional experience with this unique patient population. Results  Thirty-nine patients meeting these criteria were identified over a 13-year period from 2003 to 2016 and compared to a previously reported earlier cohort from 1992 to 2002. The most common benign pathologies included nerve sheath tumors (11%), juvenile nasopharyngeal angiofibromas (9.5%), and craniopharyngiomas (4.8%). The most common malignancies were chondrosarcoma (11%), chordoma (11%), and rabdomyosarcoma (11%). Varied surgical approaches were utilized and were similar between the two cohorts save for the increased use of endoscopic surgical techniques in the most recent cohort. The most common sites of tumor origin were the infratemporal fossa, sinonasal cavities, clivus, temporal bone, and parasellar region. Gross total resection and postoperative complication rates were similar between the two patient cohorts. Conclusions  Pediatric skull base tumors, while rare, often are treated surgically, necessitating an in depth understanding of the anatomy of the developing skull base.

Is the Mayfield Head Holder Obligatory for Intracranial Aneurysm Clipping?

Intracranial aneurysm surgery is commonly performed using pinned head holders, which pose a higher risk for the pediatric population. Several authors recommend avoiding the use of this device when it is not strictly necessary, and this is currently possible considering advances in anesthesiology and monitoring. As the literature on microsurgery without skull clamp use is scant, we report the case of a 15-year-old boy presenting with a subarachnoid hemorrhage after rupture of a middle cerebral artery aneurysm. Surgical treatment was performed with the head resting on a gel cushion horseshoe; aneurysm clipping was achieved without wakefulness or awareness and the patient had a good recovery.

Complications of Head Immobilization Devices in Children: Contact Mechanics, and Analysis of a Single Institutional Experience

BACKGROUND

Head immobilization devices (HIDs) are a staple of neurosurgical procedures, including in the intraoperative magnetic resonance imaging (iMRI) operating rooms (ORs) where material modifications were necessary for compatibility with the magnets utilized.

OBJECTIVE

To present the experience in this OR environment and discuss the multifactorial nature of the observed adverse events.

METHODS

A retrospective chart review was performed, utilizing the Department of Neurosurgery and iMRI OR databases to identify patients who suffered complications related to HIDs between November 2007 and March 2016. A literature review was also done to identify the magnitude of the problem and the availability of safety guidelines.

RESULTS

Nine hundred and forty patients underwent surgery in the iMRI OR requiring head immobilization. Seven (0.7%) suffered complications related to the HID—depressed skull fractures (n = 7) and epidural hematomas (n = 6). Age at surgery ranged from 1.6 to 10.3 yr. All patients had posterior fossa neoplasms and associated obstructive hydrocephalus. Four patients (57%) suffered permanent neurological deficits. Six patients (86%) underwent a surgical procedure to evacuate the epidural hematomas and repair the depressed skull fracture. In contrast, 1 out of 445 patient (0.2%) suffered HID-related adverse events in the conventional ORs, aged 10.2 yr.

CONCLUSION

HIDs are important to provide stability and support during neurosurgical procedures. Modifications in the material or the shape of the pins can significantly change the pressure exerted. Most of these complications are preventable if certain precautionary measures are taken especially in certain high-risk patients, and the overall benefits of HIDs continue to outweigh the risks. There is a need for consensus on guidelines for the safe use of these devices.

Headholders' - complications in neurosurgery: A review of the literature and recommendations for its use

Several types of headholders are routinely used in neurosurgical practice to secure the head in a precise position, providing better security during surgical dissection as well as an absence of eye compression during prone positions. Nevertheless, potentially lethal complications might occur. We performed a review of the literature via PubMed and Google Scholar using the terms "Mayfield skull clamp", "Sugita headholders", "headholder complications" and "skull clamp complications". Twenty-six complications directly related to the use of headholders were identified through 19 papers published from 1981 to 2014: mainly skull fractures with or without a dural laceration (50%), epidural hematomas (23.8%), skull fractures with or without a dural laceration (50%), and air embolism (9.5%). The authors propose recommendations for the safe use of headholders.

[Depressed skull fracture following the use of Mayfield headrest in adult patients: about a case and review of the literature]

Un grand nombre d'interventions neurochirurgicales nécessitent l'utilisation d'une têtière à broches pour immobiliser la tête du patient. Nous rapportons le cas d'une embarrure chez un adulte secondaire à l'utilisation de la têtière de Mayfeild. Le diagnostic a été posé en postopératoire d'une résection chirurgicale d'un médulloblastome par une tomodensitométrie cérébrale. Plusieurs facteurs semblent contribuer à augmenter le risque de complications dues à l'utilisation de la têtière de Mayfield. Les mesures de prévention sont discutées à travers une revue de littérature.

Intraoperative complications in pediatric neurosurgery: review of 1807 cases

OBJECTIVE Minimal literature exists on the intraoperative complication rate of pediatric neurosurgical procedures with respect to both surgical and anesthesiological complications. The aim of this study, therefore, was to establish intraoperative complication rates to provide patients and parents with information on which to base their informed consent and to establish a baseline for further targeted improvement of pediatric neurosurgical care. METHODS A clinical complication registration database comprising a consecutive cohort of all pediatric neurosurgical procedures carried out in a general neurosurgical department from January 1, 2004, until July 1, 2012, was analyzed. During the study period, 1807 procedures were performed on patients below the age of 17 years. RESULTS Sixty-four intraoperative complications occurred in 62 patients (3.5% of procedures). Intraoperative mortality was 0.17% (n = 3). Seventy-eight percent of the complications (n = 50) were related to the neurosurgical procedures, whereas 22% (n = 14) were due to anesthesiology. The highest intraoperative complication rates were for cerebrovascular surgery (7.7%) and tumor surgery (7.4%). The most frequently occurring complications were cerebrovascular complications (33%). CONCLUSIONS Intraoperative complications are not exceptional during pediatric neurosurgical procedures. Awareness of these complications is the first step in preventing them.

Pin-site epidural hematoma: A catastrophic complication of cranial fixation in a child

Cranial fixation with pins is a routine adjunct in neurosurgery and is usually considered safe. A rarely reported complication is skull fracture at the pin site and consequent epidural hematoma. Usually, these are picked up only postoperatively and rarely, intraoperatively if there is unexplained "brain bulge" in which case the operation should be terminated and urgent imaging has to be done. We describe such a complication that occurred while operating on a 12-year-old child with a posterior fossa tumor and review the available literature dealing with such events.

[Neuronavigation in the surgical planning of callosotomy]

OBJECTIVE

To describe the usefulness of 3D computer-assisted preoperative neuronavigation for stereoscopic location of the venous sinuses, arterial branches, and corpus callosum, to extrapolate anatomical landmarks on the surgical field and make decisions before the intervention.

METHODS

A prospective analysis was performed on patients with refractory epilepsy who underwent neuronavigation-assisted callosotomy (BRAIN LAB Dual).

RESULTS

A total of 10 neuronavigation-assisted callosotomies were performed in the year 2014. The ages of the patients (4 males and 6 females) were between 4 and 13 years (mean 7; SD 3.02). The most common indication for callosotomy in our sample was Lennox Gastoux (5 patients). A right parasagittal craniotomy was performed in 8 patients. An anterior two-thirds callosotomy was performed in 8 patients and anterior three-quarters in 2 patients. The mean accuracy of the neuronavigation procedure was less than 2mm. In no cases were there significant intraoperative surgical complications.

CONCLUSION

Callosotomy using frameless guided neuronavigation is an accurate and safe technique in patients with epilepsy refractory to surgical resection.

Preliminary experience with an intraoperative MRI-compatible infant headholder: technical note

The development of high-quality intraoperative MRI (iMRI) capability has offered a major advance in the care of patients with complex intracranial disease. To date, this technology has been limited by the need for pin fixation of the calvaria. The authors report their preliminary experience with an MRI-compatible horseshoe headrest that allows for the following: 1) iMRI in patients too young for pin fixation; 2) iMRI in patients with large calvarial defects; 3) the ability to move the head during iMRI surgery; and 4) the use of neuronavigation in such cases. The authors report 2 cases of infants in whom the Visius Surgical Theatre horseshoe headrest (IMRIS Inc.) was used. Image quality was equivalent to that of pin fixation. The infants suffered no skin issues. The use of neuronavigation with the system remained accurate and could be updated with the new iMRI information. The Visius horseshoe headrest offers a technical advance in iMRI technology for infants, for patients with cranial defects or prior craniotomies in whom pin fixation may not be safe, or for patients in whom the need to move the head during surgery is required. The image quality of the system remains excellent, and the ability to merge new images to the neuronavigation system is helpful.

Frame-based stereotactic neurosurgery in children under the age of seven: Freiburg University's experience from 99 consecutive cases

INTRODUCTION

Stereotactic frame-based procedures proved to be precise, safe and are of widespread use among adult patients. Regarding pediatric patients few data is available, therefore the use of the stereotactic frame remains controversial in this population. This motivated us to report our experience in stereotactic procedures in the youngest patients and review the literature concerning this subject.

METHODS

All frame-based procedures performed in patients younger than seven years in the University of Freiburg during the last 10 years were retrospectively analyzed and discussed under the light of the current literature.

RESULTS

The studied population was composed of 72 patients under the age of seven (mean 3.4±2.1 years-old), in whom 99 stereotactic procedures were performed. Brain tumor was present in 60 patients, hydrocephalus in five, cystic lesions in three, intracranial abscess in three and epilepsy in one patient. Stereotactic surgery was performed in 36 cases for brachytherapy, in 29 for biopsy, in 20 cases for cyst puncture, in eight for stereotactically guided endoscopic ventriculostomy, in five for catheter placement and in one case for depth electrode insertion. The overall complication rate was 5%. There were three cases of pin penetration through the skull, one case of frame dislocation after extensive cyst drainage and two skull fractures. Neurologic deficit related to frame fixation was observed in none of the cases. In disagreement with other authors, no case of pin related infection, air embolism, hematoma or CSF leak was observed.

CONCLUSION

Frame-based stereotactic neurosurgery is a safe technique also in the youngest patients. Rather than the simple use of torque-limiting devices training and experience in the manual adjustment of the stereotactic frame in children have been proven to be crucial factors that contribute to reducing pin related complications.

Difference between conventional head-pin and Dispo-pin in the Sugita multipurpose head frame system

Head fixation devices are commonly used in neurosurgical procedures and are considered essential tools for microneurosurgery. The Sugita multipurpose head frame system is one of such systems and has been used for more than 30 years worldwide. It is important to understand how to fix a patient's head with head-pins safely, because there are no numerical parameters for head-pin screwing in the Sugita frame. Recently, the Dispo-pin has been available for disposable use as a head-pin in the Sugita frame. In contrast to the conventional head-pin, the tip of the Dispo-pin is separable from the body. Although their appearance is similar, the torque for adequate fixation is different. The relationships between torque and vertical force were analyzed. The torque of the head-pin was linearly correlated with vertical force for both types of head-pin. Different conditions caused different torque increase against a specific increase of vertical force with the conventional head-pin. In contrast, torque increase against a specific increase of vertical force with the Dispo-pin was the same regardless of the situation. The torque originates from friction between the scalp and tip of the conventional head-pin. As friction is different for each patient's condition, the torque at this part is different. The friction between the tip and body of the Dispo-pin is lower than that between the scalp and tip of the head-pin. In consequence, the torque generated from the tip of the Dispo-pin is the same in each situation. It is important to understand the difference between the Dispo-pin and conventional head-pin.

Multiple epidural hematomas and hemodynamic collapse caused by a subgaleal drain and suction-induced intracranial hypotension: case report

BACKGROUND AND IMPORTANCE

Subgaleal drains are commonly used in neurosurgery. Rare complications attributed to these drains have been described. We present a rare complication of hemodynamic collapse and multiple epidural hematomas attributed to intracranial hypotension induced by a subgaleal drain connected to suction during wound closure.

CLINICAL PRESENTATION

A 3.5-year-old boy underwent an uneventful occipital lobectomy and titanium mesh cranioplasty for resection of a recurrent choroid plexus carcinoma. The child had undergone 2 uneventful previous resections and cranial irradiation. During skin closure, a subgaleal drain was connected to suction to keep the surgical bed dry. Immediately after completion of the subgaleal layer closure, there was an acute hemodynamic collapse, accompanied by bradycardia and a drop in the hematocrit. After successful resuscitation, the child underwent a brain computed tomography scan that showed a large bifrontal epidural hematoma and multiple additional small epidural hematomas. The large hematoma was surgically evacuated, and the child had an uneventful recovery.

CONCLUSION

Acute negative intracranial hypotension may cause bradycardia, epidural hematomas, and hemodynamic collapse. Subgaleal drains should not be connected to suction systems, and care should be taken when these drains are connected to vacuum bulbs in high-risk cases such as after cranial irradiation, large resections, and mesh cranioplasties.

Management of blunt extracranial traumatic cerebrovascular injury: a multidisciplinary survey of current practice

BACKGROUND

Extracranial traumatic cerebrovascular injury (TCVI) is present in 1-3% of all blunt force trauma patients. Although options for the management of patients with these lesions include anticoagulation, antiplatelet agents, and endovascular treatment, the optimal management strategy for patients with these lesions is not yet established.

OBJECTIVE

Multidisciplinary survey of clinicians about current management of TCVI.

METHODS

A six-item multiple-choice survey was sent by electronic mail to a total of 11,784 neurosurgeons, trauma surgeons, stroke neurologists, and interventional radiologists. The survey included questions about their choice of imaging, medical management, and the use of endovascular techniques. Survey responses were analyzed according to stated specialty.

RESULTS

Seven hundred eighty-five (6.7%) responses were received. Overall, a total of 325 (42.8%) respondents favored anticoagulation (heparin and/or warfarin), 247 (32.5%) favored antiplatelet drugs, 130 (17.1%) preferred both anticoagulation and antiplatelet drugs, and 57 (7.5%) preferred stenting and/or embolization. Anticoagulation was the most commonly preferred treatment among vascular surgeons (56.9%), neurologists (50.2%) and neurosurgeons (40.7%), whereas antiplatelet agents were the most common preferred treatment among trauma surgeons (41.5%). Overall, 158 (20.7%) of respondents recommended treatment of asymptomatic dissections and traumatic aneurysms, 211 (27.7%) did not recommend it, and 39.4% recommended endovascular treatment only if there is worsening of the lesion on follow-up imaging.

CONCLUSIONS

These data demonstrate the wide variability of physicians' management of traumatic cerebrovascular injury, both on an individual basis, and between specialties. These findings underscore the need for multicenter, randomized trials in this field.

Depressed skull fracture by a three-pin head holder: a case illustration

BACKGROUND AND CASE REPORT: Many surgical procedures require a rigid immobilization of the patients' head, which is usually achieved by using a pin-type head holder. We briefly illustrate the case of a 4-year-old girl who sustained a depressed skull fracture by penetration of a pin of the head holder. The fracture was noted at the end of the surgery performed for treatment of a cerebellar astrocytoma and was managed conservatively.

DISCUSSION

Several factors seem to be involved in the production of this complication as are faulty application of the pins, excessive pin pressure, skull thinning, young patient's age, and pathological conditions that evolve with long-standing raised intracranial pressure. Prevention and management measures are briefly discussed.

Acute unilateral enlargement of the parotid gland immediately post craniotomy in a pediatric patient: a case report

A temporary acute unilateral enlargement of the parotid gland or "anesthesia mumps" has been described in both surgical and anesthesia literature. It has been described in elderly, dehydrated, poorly nourished, and post-operative patients. We present a 5-year-old patient who underwent a left temporal craniotomy for seizure focus resection and quadriceps muscle biopsy. Immediately post procedure, he was noted to have an acute unilateral enlargement of the right parotid gland. We report acute unilateral parotitis as a possible, but uncommon, complication of positioning in the pediatric population and to discuss possible pathophysiology and prevention, as well as a review of the available literature.

Combined Transventricular and Supracerebellar Infratentorial Approach Preserving the Vermis in Giant Pediatric Posterior Fossa Midline Tumors

Objective:

Giant pediatric midline tumors of the posterior fossa involving the fourth ventricle and the tectal region are difficult to approach and present a high risk of postoperative neurological deficits. Children with sequelae such as cerebellar mutism and ataxia experience a compromise in their quality of life. Here, we present our combined transventricular and supracerebellar infratentorial approach to avoid complications of vermian splitting.

Methods:

The combined transventricular and supracerebellar infratentorial approach described here was used in a total of four pediatric patients. A medial suboccipital craniotomy with opening of the foramen magnum and resection of the C1 lamina was performed with the patient in the semisitting position. The tumor mass filling the fourth ventricle was removed via a transventricular telovelar route through the foramen of Magendie, preserving the vermis. The rostral tumor portions in the peritectal region extruding up to the thalami were exposed and resected via an infratentorial supracere-bellar route to preserve the venous drainage of the cerebellum.

Results:

There were no new neurological deficits postoperatively. Two patients had low-grade astrocytomas, and two patients had malignant tumors. Complete tumor resection was achieved in two patients, and near-total tumor removal in the two others. CONCLUSION: The combined transventricular and supracerebellar infratentorial approach offers a unique possibility of safely removing giant pediatric midline tumors. Splitting of the cerebellar vermis is not necessary for removal of such tumors.