Flexible endoscopic assistance in the surgical management of vestibular schwannomas.

Endoscopic-assisted techniques have extensively been applied to vestibular schwannoma (VS) surgery allowing to increase the extent of resection, minimize complications, and preserve facial nerve and auditory functions. In this paper, we retrospectively analyze the effectiveness of flexible endoscope in the endoscopic-assisted retrosigmoid approach for the surgical management of VS of various sizes. The authors conducted a retrospective analysis on 32 patients who underwent combined microscopic and flexible endoscopic resection of VS of various sizes over a period of 16 months. Flexible endoscopic-assisted retrosigmoid approach was performed in all cases, and in 6 cases, flexible and rigid endoscopic control were used in combination to evaluate the differences between the two surgical instruments. The surgical results were additionally compared with a previous case series of 141 patients operated for VS of various sizes without endoscopic assistance. Gross-total resection was achieved in 84% of the cases and near-total resection was accomplished in the rest of them. Excellent or good facial nerve function was observed in all except one case with a preoperative severe facial palsy. Hearing preservation surgery (HPS) was attempted in 11 cases and accomplished in 9 (81.8%). A tumor remnant was endoscopically identified in the fundus of the IAC in all cases (100%). Endoscopic assistance increased the rate of total removal and no intrameatal residual tumor was seen at radiological follow-up. Comparative analysis with a surgical cohort of patients operated with the sole microsurgical technique showed a significative association between endoscopic assistance and intracanalicular extent of resection. Combined microsurgical and flexible endoscopic assistance provides remarkable advantages in the pursuit of maximal safe resection of VS and preservation of facial nerve and auditory functions, minimizing the risk of post-operative complications.

A novel omnidirectional tin-alloyed ring retractor for craniotomy in neurosurgery: technical note.

In neurosurgical operations, proper craniotomy using retractors is necessary. Various surgical instruments are used for this purpose, including standard retractors and multipurpose head frame retractor systems. However, the conventional multipurpose head frame system is often not optimal for use in some craniotomies and postures because of its size and complexity of setting. We have invented a new omnidirectional tin-alloyed (ODT) ring retractor for craniotomy with malleability and shape memory characteristics to resolve these issues. It is principally elliptical in shape, approximately 30 × 20 cm in diameter, and sufficiently firm. Accordingly, this ODT ring can retract the surgical field in all directions. Here, we report our experiences of 281 neurosurgical craniotomies using this ODT ring retractor system in various craniotomy sites and postures. Our novel ODT ring retractor is useful because of its low profile, multidirectional retractability, and less obstructiveness with its malleability. It could be used with pediatric patients where strong traction is not desirable.

Comparative anatomical study on the role of zygomatic osteotomy in the extradural subtemporal approach to the clival region, when less is more.

PURPOSE: A great concern in performing the extradural subtemporal approach (ESTA) is the evaluation of the actual advantage provided by zygomatic osteotomy (ZO). Complications related to zygomatic dissection have been widely reported in the literature, making it of paramount importance to balance the actual need to perform it, against the risk of maneuver-related morbidity. Authors comparatively analyze the putative advantage provided by ZO in the ESTA in terms of anatomic exposure and surgical operability. Technical limits and potentials are critically revised and discussed. METHODS: A comparative microanatomical laboratory investigation was conducted. The operability score (OS) was applied for quantitative analysis of surgical operability. RESULTS: ZO was found to provide a weakly significant improvement in the surgical angle of attack (p value 0.01) (mean increase 3°). Maneuverability arch (MAC) increase related to ZO did not reach statistical significance (p value 0.09) (mean increase 2°). The variations provided by MAC increase on the conizing effect (CE) did not lead to an actual advantage in the real surgical scenario, modifying the vision area (VA) in terms of reduction of central vision area (CA) in favor of an increase of peripheral vision area (PA) only in the most caudal part of the surgical field. Ultimately, ZO did not influence the overall OS, scoring both ESTA-ZO+ and ESTA-ZO- 2 out of 3. CONCLUSION: In the ESTA, ZO does not provide an actual significant advantage in terms of surgical operability on clival and paraclival areas.

The craniotomy box: an innovative method of containing hazardous aerosols generated during skull saw use in autopsy on a COVID-19 body.

During a disease pandemic, there is still a requirement to perform postmortem examinations within the context of legal considerations. The management of the dead from COVID-19 should not impede the medicolegal investigation of the death where required by the authorities and legislation but additional health and safety precautions should be adopted for the necessary postmortem procedures. The authors have therefore used the craniotomy box in an innovative way to enable a safe alternative for skull and brain removal procedures on suspected or confirmed COVID-19 bodies. The craniotomy box technique was tested on a confirmed COVID-19 positive body where a full postmortem examination was performed by a team of highly trained personnel in a negative pressure Biosafety Level 3 (BSL-3) autopsy suite in the National Institute of Forensic Medicine (IPFN) Malaysia. This craniotomy box is a custom-made transparent plastic box with five walls but without a floor. Two circular holes were made in one wall for the placement of arms in order to perform the skull opening procedure. A swab to detect the presence of the SARS-CoV-2 virus was taken from the interior surface of the craniotomy box after the procedure. The result from the test using real-time reverse transcriptase polymerase chain reaction (rRT-PCR) proved that an additional barrier provided respiratory protection by containing the aerosols generated from the skull opening procedure. This innovation ensures procedures performed inside this craniotomy box are safe for postmortem personnel performing high risk autopsies during pandemics.

Self-releasing of a titanium clamp (CranioFix) in cranioplasty.

The CranioFix® titanium clamp was developed for fixing bone flaps after craniotomy. In this case, to prevent cosmetic problems, the bone flaps were trimmed with a beveled edge, and a CranioFix clamp was used for bone flap fixation. As the brain swelled, the CranioFix clamp became loosened. If brain swelling is anticipated and bone margins have been trimmed, it may be better to consider other fixation methods.

Craniotomy bone flap fixation: revisiting the use of bone struts.

INTRODUCTION: Bone flap fixation after craniotomy is a standard part of neurosurgical practice. Several techniques and devices exist, though no ideal strategy has been identified. The key aims are to prevent infection and to achieve adequate cosmesis and bony fusion whilst also minimising costs and complications. Ease of use must also be considered. Fixation with sutures and bony struts in the kerf has been described in children and adults and, although the technique achieves many of the ideals of fixation, it does not seem to have been popularised. We report our experience of using the strut technique. METHODS: A retrospective review of our cranial surgery database, operative notes and follow-up records was conducted. 300 applicable craniotomies were carried out in 8 years. Struts were used in 81 cases and comments on the bony contour described in 21 follow-up records. RESULTS: In nineteen, the contour was perfect. In one, there was a small bony depression; and in one, there was a small ridge in the posterior part. No repeat operations were carried out for surgery or cosmesis. CONCLUSIONS: We report our results with a view to reminding the neurosurgical community of the existence of a technique that achieves all the criteria of the ideal fixation strategy.

Prototype screwdriver stopper to avoid intracranial penetration injury.

Screwdriver slipping from the tapping screw head (screwdriver slip) represents a very dangerous situation that leads to the risk of entry into the intracranial operation field. We have developed a screwdriver stopper device to attach to the top of the screwdriver in order to prevent intracranial penetration injuries. We performed 48 craniotomies in our institute. The instrument is made from clear acrylic with a central hole (diameter, 3 mm). We checked the number of screwdriver slip events, as a precursor to intracranial penetration injury, in screwdrivers from five different companies, and compared the results. We used 496 tapping screws in 512 tightening procedures. Although screwdriver slip occurred at an overall rate of 17/512(3.3%), we completely avoided serious intracranial penetration injuries. No significant differences in rates of screwdriver slip were seen between the five companies (χ2 test, p = 0.997). Screwdriver slip is a precursor to intracranial penetration injury, but cannot be avoided with cross-type screwdrivers. Many neurosurgeons may be operating without knowledge of the potential risk of intracranial penetration injury. The screwdriver stopper described herein may prove extremely useful for preventing intracranial penetration injuries during neurological surgery.

A Standard Operating Procedure of Clean and Fast Craniotomy Without Application of Raney Clips.

Clean and fast craniotomy and closure (CAC) is a fundamental part of modern microneurosurgery, and is an essential technique that young neurosurgeons shall master. The hemostatic instruments of CAC have evolved from forceps to raney clips. Thanks to the wide application of bipolar coagulation, local infiltration anesthesia combined with cauterization is become an effective method of hemostasis. The authors worked out a standard operating procedure (SOP) of CAC assisted by fishhooks without the application of raney clips. According to the authors' experience, the average time spent on CAC decreased from more than 1 hour to <40 minutes. Owning to little bleeding, the operative field is clean throughout the procedure. Patients also experience less pain and enjoy an earlier discharge. With few complications, the authors believe that this cost-effective SOP may become a cornerstone of early recovery after surgery.

Power-Assisted Particulate Bone Grafting Effectively Prevents Osseous Defects After Cranial Vault Reconstruction.

BACKGROUND: Cranial vault reconstruction (CVR) is the gold standard in the operative treatment of craniosynostosis. Full thickness osseous defects (FTOD) of the calvaria have been observed in 5% to 15% patients after CVR, with higher rates cited in the fronto-orbital advancement (FOA) subset. Particulate bone graft (PBG) harvested manually has been shown to decrease FTOD after FOA from 24% to 5.5%. The authors used a modified technique using a powered craniotome, with the hypothesis that the technique would also improve outcomes. METHODS: A retrospective review was performed of patients who underwent CVR for craniosynostosis between 2004 and 2014. Patient demographics, diagnosis, age, operative details, and postoperative care were reviewed in detail. Categorical, nonparametric variables were compared by Fisher exact tests. RESULTS: A total of 135 patients met inclusion criteria. The most common diagnoses were metopic (n = 41), sagittal (n = 33), and unilateral coronal craniosynostosis (n = 31); 65% (n = 88) underwent FOA, 29% (n = 39) underwent single-stage total vault reconstruction, and 6% (n = 8) had a posterior vault reconstruction. CVR was performed without PBG in 95 patients and with PBG in 40 patients. Without PBG, FTOD were discovered on clinical examination in 18% of patients (n=17): 11 presented with subcentimeter defects, while 6 had larger defects requiring revision cranioplasty (6% operative revision rate). Among those receiving PBG, 1 patient presented a subcentimeter FTOD (2.5% FTOD incidence and 0% operative revision rate). CONCLUSION: Particulate bone graft harvested with a powered device decreases the rate of FTOD and reoperation rate after CVR for craniosynostosis.

Outcomes of Titanium Mesh Cranioplasty in Pediatric Patients.

PURPOSE: Cranial defects in children have been repaired with various materials ranging from autologous bone to synthetic materials. There is little published literature on the outcomes of titanium mesh cranioplasty (TMC) in calvarial reconstruction in the pediatric population. This study evaluates a pediatric cohort who underwent calvarial defect reconstruction with titanium mesh and assesses the efficacy and outcomes of TMC. METHODS: An Institutional Review Board approved retrospective review of patients ≤18 years of age who underwent cranioplasty from 1999 to 2014 at 2 centers was performed. The cohort undergoing TMC was studied. RESULTS: A total of 159 cranioplasties were performed. Autologous reconstruction included 84 bone flap replacements and 36 split calvarial bone graft reconstructions. Six patients underwent PEEK implant reconstruction. Titanium mesh cranioplasty was performed on 33 patients. Two patients underwent 2 separate cranioplasties. The median age of patients was 6 years (19 months to 18 years). The most common underlying etiologies were congenital syndromes/craniosynostosis (13 patients), and trauma (11). The majority of patients had prior cranial surgeries (85%). Various types of titanium mesh were used with sizes ranging from 2×3 cm to 19×20 cm, with some patients requiring distinct areas of defect reconstruction. Perioperative complications were noted in 2 patients that subsequently improved. Two patients had late soft tissue problems with complications of wound infections requiring resection of a portion of the mesh. Patients were followed an average of 4 years (range 13 days to 6.8 years), with 2 patients lost to follow-up. Overall, all patients with follow-up achieved a cranial contour with good symmetry to the unaffected side, as well as effective protection to the brain. CONCLUSIONS: Titanium mesh cranioplasty is an effective option for correcting pediatric cranial defects when autologous bone availability is limited and soft tissue coverage allows placement of an implant. The interim outcome for these patients is favorable with few complications and no evidence of growth restriction in the authors' series. Follow-up will be ongoing for these patients.

Complications of a poly-L-lactic acid and polyglycolic acid osteosynthesis device for internal fixation in maxillofacial surgery.

The purpose of this study was to retrospectively evaluate and examine the incidence of complications using poly-L-lactic acid and polyglycolic acid (PLLA/PGA) copolymer plate system in maxillofacial osteosynthesis. The retrospective study included 87 patients (50 men, 37 women), who needed maxillofacial surgery. We examined the proportion of complications and their factors from clinical data. A comparison was also made for plate decomposition using the molecular weight of the plate without plate exposure and complications. Osteosynthesis sites healed in all patients. Ten cases (11.5%) showed plate exposure-related complications, with all occurring at intraoral surgical sites. There was no significant difference in molecular weight changes of plates in resorbable process. Statistical analysis of study variables between patients with and without exposed plates showed that the plate thickness was significantly associated with the risk of exposed plates (p < 0.05). The commercially available PLLA/PGA device could be a useful rapid resorbable material for maxillofacial osteosynthesis. When thick plates are used on the intraoral site, it may be necessary to pay attention to the complication of plate exposure. Even if exposure-related complications have occurred, resorption and degradation of this material proceeds, suggesting the ease of appropriate risk management.

Corpus callosotomy-Open and endoscopic surgical techniques.

Corpus callosotomy is a palliative surgical procedure for patients with refractory epilepsy. It can be performed through an open approach via a standard craniotomy and the aid of an operating microscope, or alternatively via a mini-craniotomy with endoscope assistance. The extent of callosal disconnection performed varies according to indications and surgeon preference. In this article, we describe both open and endoscopic surgical techniques for anterior and complete corpus callosotomy.

Hydroxyapatite ceramic implants for cranioplasty in children: a single-center experience.

PURPOSE: The use of hydroxyapatite ceramic (HAC) implants for the treatment of skull defects in pediatric patients started 2010 at our institution. Ceramic implants facilitate osteoblast migration and therefore optimize osteointegration with the host bone. The purpose of this study is to report a single-center experience with this treatment modality. METHODS: A retrospective review of all patients from July 2010 through June 2014 undergoing a cranioplasty using hydroxyapatite ceramic implant and managed at a single institution was performed. Indication for cranioplasty, the hospital course, and follow-up were reviewed. Bone density was measured in Hounsfield Units (HU) and osteointegration was calculated using Mimics Software® (Mimics Innovation Suite v17.0 Medical, Materialize, Leuven, Belgium). RESULTS: Over the 4-year period, six patients met criteria for the study. Five patients had an osteointegration of nearly 100%. One patient had an incomplete osteointegration with a total bone-implant contact area of 69%. The mean bone density was 2800 HU (2300-3000 HU). Bone density alone is estimated to have a Hounsfield value between 400 and 2000 HU depending on the body region and bone quality. There were no major complications, and the patients were highly satisfied with the esthetical result. CONCLUSION: Hydroxyapatite ceramic implants for cranioplasty in pediatric patients are a good choice for different indications. The implants show excellent osteointegration and esthetical results.

Comparison of Resorbable Plating Systems: Complications During Degradation.

INTRODUCTION: Several bioresorbable plating systems have become standard in pediatric craniosynostosis reconstruction. A comparison of these systems is needed to aid surgeons in the preoperative planning process. The authors aim to evaluate 1 institution's experience using Resorb-X by KLS Martin and Delta Resorbable Fixation System by Stryker (Stryker Craniomaxillofacial, Kalamazoo, MI). METHODS: A sample of patients with single-suture nonsyndromic craniosynostosis treated at St Louis Children's Hospital between 2007 and 2014 using either Resorb-X or Delta bioresorbable plating systems were reviewed. Only patients with preoperative, immediate, and long-term 3-dimensional photographic images or computed tomography scans were included. A comparison of plating system outcomes was performed to determine the need for clinic and emergency room visits, imaging obtained, and incidence of subsequent surgical procedures due to complications. RESULTS: Forty-six patients (24 Resorb-X and 22 Delta) underwent open repair with bioabsorbable plating for single suture craniosynostosis. The mean age at each imaging time point was similar between the 2 plating systems (P > 0.717). Deformity-specific measures for sagittal (cranial index), metopic (interfrontotemporale), and unicoronal (frontal asymmetry) synostosis were equivalent between the systems at all time points (0.05 < P < 0.904). A single Delta patient developed bilateral scalp cellulitis and abscesses and subsequently required operative intervention and antibiotics. CONCLUSION: Bioabsorbable plating for craniosynostosis in children is effective and has low morbidity. In our experience, the authors did not find a difference between the outcomes and safety profiles between Resorb-X and Delta.

Technical aspects of pediatric epilepsy surgery: Report of a multicenter, multinational web-based survey by the ILAE Task Force on Pediatric Epilepsy Surgery.

Surgical techniques may vary extensively between centers. We report on a web-based survey aimed at evaluating the current technical approaches in different centers around the world performing epilepsy surgery in children. The intention of the survey was to establish technical standards. A request was made to 88 centers to complete a web-based survey comprising 51 questions. There were 14 questions related to general issues, 13 questions investigating the different technical aspects for children undergoing epilepsy surgery, and 24 questions investigating surgical strategies in pediatric epilepsy surgery. Fifty-two centers covering a wide geographic representation completed the questionnaire. The median number of resective procedures per center per year was 47. Some important technical practices appeared (>80% of the responses) such as the use of prophylactic antibiotics (98%), the use of high-speed drills for bone opening (88%), nonresorbable material for bone flap closure (85%), head fixation (90%), use of the surgical microscope (100%), and of free bone flaps. Other questions, such as the use of drains, electrocorticography (ECoG) and preoperative withdrawal of valproate, led to mixed, inconclusive results. Complications were noted in 3.8% of the patients submitted to cortical resection, 9.9% hemispheric surgery, 5% callosotomy, 1.8% depth electrode implantation, 5.9% subdural grids implantation, 11.9% hypothalamic hamartoma resection, 0.9% vagus nerve stimulation (VNS), and 0.5% deep brain stimulation. There were no major differences across regions or countries in any of the subitems above. The present data offer the first overview of the technical aspects of pediatric epilepsy surgery worldwide. Surprisingly, there seem to be more similarities than differences. That aside many of the evaluated issues should be examined by adequately designed multicenter randomized controlled trials (RCTs). Further knowledge on these technical issues might lead to increased standardization and lower costs in the future, as well as definitive practice guidelines.

A method of posterior fossa dural incision to minimize hemorrhage from the occipital sinus: the "mosquito" method.

PURPOSE: The posterior fossa dural opening requires the ligation of the occipital sinus to gain successful exposure. However, there could be a prominent occipital sinus which is functioning as the main drainage route and is harboring the risk of unpredictable massive hemorrhage during the dural opening. We introduce a safe method of posterior fossa dural incision to minimize hemorrhage from the occipital sinus using four curved hemostat clamps. METHODS: For the dural incision at the midline part of the posterior cranial fossa, we used four curved hemostat clamps to occlude the prominent occipital sinus: one pair of clamps at the proximal part and the other pair at the distal part to occlude the occipital sinus. Dural incision was made between the two pairs of the curved hemostat clamps. RESULTS: By clamping of the sinus, it allows observation of possible brain swelling after occlusion of the occipital sinus as well as minimizes hemorrhage during incision of the midline dura of the posterior fossa. CONCLUSION: This method allows observation of brain swelling after occipital sinus occlusion and is an easy and safe incision of the midline dura minimizing hemorrhage in selected cases with a prominent occipital sinus.

Comparison of Intracranial Volume and Cephalic Index After Correction of Sagittal Synostosis With Spring-assisted Surgery or Pi-plasty.

BACKGROUND: The aim of the current study was to determine the intracranial volume (ICV) and cephalic index (CI) in patients operated for sagittal synostosis, and to compare the outcome of 2 different surgical techniques: craniotomy combined with springs and modified pi-plasty. METHODS: The authors studied all patients who had been operated for isolated sagittal synostosis and registered in the Gothenburg Craniofacial Registry until the end of 2012 and who had undergone a preoperative and/or postoperative (at 3 years of age) computed tomography examination. Sex- and age-matched controls were identified from children who had undergone computed tomography for other reasons. RESULTS: Craniotomy combined with springs increased the ICV and CI from 802 ±â€Š127 mL (mean ±â€ŠSD) and 70.1 ±â€Š4.0 to 1300 ±â€Š158 mL and 73.1 ±â€Š3.3, respectively. The corresponding values for controls were 796 ±â€Š136 mL and 83.6 ±â€Š7.3 preoperatively and 1334 ±â€Š136 mL and 80.0 ±â€Š4.5 at 3 years of age. Pi-plasty increased the ICV and CI from 1014 ±â€Š115 mL and 69.7 ±â€Š3.3 to 1286 ±â€Š122 mL and 74.1 ±â€Š2.6, respectively. Corresponding values for controls were 1043 ±â€Š153 mL and 83.4 ±â€Š7.0 preoperatively and 1362 ±â€Š122 mL and 79.6 ±â€Š3.9 at 3 years of age. CONCLUSIONS: There was no significant difference between craniotomy combined with springs in children younger than 6 months and pi-plasty in older children regarding the efficacy of improving ICV and CI. Neither of the techniques fully normalized the head shape.

A Systematic Approach to Predicting Spring Force for Sagittal Craniosynostosis Surgery.

Spring-assisted surgery (SAS) can effectively treat scaphocephaly by reshaping crania with the appropriate spring force. However, it is difficult to accurately estimate spring force without considering biomechanical properties of tissues. This study presents and validates a reliable system to accurately predict the spring force for sagittal craniosynostosis surgery. The authors randomly chose 23 patients who underwent SAS and had been followed for at least 2 years. An elastic model was designed to characterize the biomechanical behavior of calvarial bone tissue for each individual. After simulating the contact force on accurate position of the skull strip with the springs, the finite element method was applied to calculating the stress of each tissue node based on the elastic model. A support vector regression approach was then used to model the relationships between biomechanical properties generated from spring force, bone thickness, and the change of cephalic index after surgery. Therefore, for a new patient, the optimal spring force can be predicted based on the learned model with virtual spring simulation and dynamic programming approach prior to SAS. Leave-one-out cross-validation was implemented to assess the accuracy of our prediction. As a result, the mean prediction accuracy of this model was 93.35%, demonstrating the great potential of this model as a useful adjunct for preoperative planning tool.