Biomimetic and Nonbiomimetic Approaches in Dura Substitutes: The Influence of Mechanical Properties.

The dura mater, the furthest and strongest layer of the meninges, is crucial for protecting the brain and spinal cord. Its biomechanical behavior is vital, as any alterations can compromise biological functions. In recent decades, interest in the dura mater has increased due to the need for hermetic closure of dural defects prompting the development of several substitutes. Collagen-based dural substitutes are common commercial options, but they lack the complex biological and structural elements of the native dura mater, impacting regeneration and potentially causing complications like wound/postoperative infection and cerebrospinal fluid (CSF) leakage. To face this issue, recent tissue engineering approaches focus on creating biomimetic dura mater substitutes. The objective of this review is to discuss whether mimicking the mechanical properties of native tissue or ensuring high biocompatibility and bioactivity is more critical in developing effective dural substitutes, or if both aspects should be systematically linked. After a brief description of the properties and architecture of the native cranial dura, we describe the advantages and limitations of biomimetic dura mater substitutes to better understand their relevance. In particular, we consider biomechanical properties' impact on dura repair's effectiveness. Finally, the obstacles and perspectives for developing the ideal dural substitute are explored.

A case of arteriovenous malformation of the hand and its outcome.

INTRODUCTION AND IMPORTANCE: AVMs are rarest congenital anomalies constituting around 1% of pediatric population. Arteriovenous malformations originate at 4th to 10th weeks of intra uterine life due to persistence of primitive arteriovenous shunts. Though the exact prevalence is unknown, upper limb constitute around 10 % of all AVMs. Hand being the most common region affected after head and neck. CASE PRESENTATION: Author is presenting here a rare case of palmar arteriovenous malformation in child since birth, hindering her routine daily activities, and its unique way of surgical management. CLINICAL DISCUSSION: Hand arteriovenous malformations (AVMs) are challenging to treat due the necessity to maintain function and aesthetic appearance. CONCLUSION: The risk of fatal bleeding makes resection of AVMs a challenging and stressful procedure, but however in the presence of available efficient equipments to control the bleeding and expertise of the available treating surgeons, primary surgical resection can be considered a feasible option in a tertiary care pediatric center.

Bovine Pericardium Treated with Polyethylene Glycol and Ethanol Versus Pericranium for Duraplasty: A Pilot Study in Supratentorial Neurosurgery.

BACKGROUND: Watertight closure of dura mater after intracranial surgery can avoid cerebrospinal fluid leakage and central nervous system infection and herniation. When primary closure is not possible, the pericranium is the preferential choice. When it is not available, a dural substitute becomes necessary. Bovine pericardium treated with polyethylene glycol and ethanol is herein tested as a dural substitute. METHODS: A pilot study comparing bovine pericardium with pericranium in supratentorial neurosurgery was performed. RESULTS: Twenty patients were initially allocated into a bovine pericardium group (group 1) or a pericranium group (group 2). Three patients from group 1 and 2 from group 2 had a loss of follow-up, being excluded. In the remaining 15 patients, epidemiological analysis demonstrated a male:female ratio of 3:4 and 4:4 for groups 1 and 2. Ages varied from 28 to 68 (Mean = 49.6) in group 1 and 40-80 (Mean = 61.2) in group 2, with a mean difference of 11.68 years (P = 0.09). Two cases of surgical site infection and 1 of hydrocephalus were observed. Although the calculated relative risk for complications was higher in group 1 (Relative Risk = 1.08), Fisher exact test demonstrated no statistically significant difference between groups (P = 1.00). Procedure mean time was 23 minutes and 11 seconds in group 1 versus 27 minutes and 55 seconds in group 2 (P = 0.47). Mean graft area was 13.17 and 6.23 cm2 in groups 1 and 2 (P = 0.02). CONCLUSIONS: Bovine pericardium treated with polyethylene glycol and ethanol was comparable to pericranium as a dural substitute. More studies are encouraged to certify our findings.

Post-Operative Complications after Foramen Magnum Decompression with Duraplasty Using Different Graft Materials in Adults Patients with Chiari I Malformation: A Systematic Review and Meta-Analysis.

Despite extensive investigations, the choice of graft material for reconstructive duraplasty after foramen magnum decompression for Chiari type I malformation (CMI) is still a topic of discussion. The authors performed a systematic review and meta-analysis of the literature examining the post-operative complications in adult patients with CMI after foramen magnum decompression and duraplasty (FMDD) using different graft materials. Our systematic review included 23 studies with a total of 1563 patients with CMI who underwent FMDD with different dural substitutes. The most common complications were pseudomeningocele (2.7%, 95% CI 1.5-3.9%, p < 0.01, I2 = 69%) and CSF leak (2%, 95% CI 1-2.9%, p < 0,01, I2 = 43%). The revision surgery rate was 3% (95% CI 1.8-4.2%, p < 0.01, I2 = 54%). A lower rate of pseudomeningocele was observed with autologous duraplasty when compared with synthetic duraplasty (0.7% [95% CI 0-1.3%] vs. 5.3% [95% CI 2.1-8.4%] p < 0.01). The rate of CSF leak and revision surgery was lower after autologous duraplasty than after non-autologous dural graft (1.8% [95% CI 0.5-3.1%] vs. 5.3% [95% CI 1.6-9%], p < 0.01 and 0.8% [95% CI 0.1-1.6%] vs. 4.9% [95% CI 2.6-7.2%] p < 0.01, respectively). Autologous duraplasty is associated with a lower rate of post-operative pseudomeningocele and reoperation. This information should be considered when planning duraplasty after foramen magnum decompression in patients with CMI.

Posterior Fossa Decompression with or Without Duraplasty for Chiari I Malformation.

Posterior fossa decompression (PFD) with/without duraplasty is the standard surgical treatment for symptomatic CM-1. Posterior fossa decompression without duraplasty (PFD) may be associated with shorter operative times and hospital stays, fewer complications, and may yield improvements in symptoms and syrinx sizes. Posterior fossa decompression with duraplasty (PFDD) may be associated with superior long-term symptomatic improvements, larger syrinx reductions, and a lower need for revision decompression. Various dural graft materials may be used for PFDD, though the ideal type of graft has not been definitively established. Other adjunct surgical procedures may be added to PFD/PFDD given certain symptomatic or anatomical considerations.

Follow-up study of a patient with early onset cerebral amyloid angiopathy following childhood cadaveric dural graft.

We retrospectively studied the T2 star (T2*)-weighted magnetic resonance imaging (MRI) of a 40-year-old patient diagnosed with symptomatic early-onset cerebral amyloid angiopathy (CAA), occurring 34 years following childhood neurosurgery using a cadaveric dural patch. Our findings revealed that CAA associated with cadaveric dural transplantation could progress rapidly, sometimes with bilateral bleeding. This microbleed evolution is suggestive of water-soluble amyloid-ß transmission via cerebrospinal fluid alongside perivascular drainage pathways with deposition in the cerebral artery walls due to clearance disturbances. Multiple intracerebral hemorrhages associated with CAA with a childhood cadaveric dural graft should be considered a life-threatening medical complication.

Sterile Gelatin Film Reduces Cortical Injury Associated With Brain Tumor Re-Resection.

BACKGROUND: Recurrent intracranial tumors frequently require re-resection. Dural adhesions to the cortex increase the morbidity and duration of these revision craniotomies. OBJECTIVE: To describe the use of commercially available sterile gelatin film to prevent meningocerebral adhesions and decrease the rate of surgically induced ischemia from revision craniotomy. METHODS: This retrospective cohort study examined patients with recurrent glioma, meningioma, and metastasis who underwent re-resection at least 30 d following their initial tumor resection. Cortical surface tissue ischemia after re-resection on diffusion-weighted magnetic resonance imaging was compared for patients with (gelatin film group) and without (nongelatin film group) a history of gelatin film placement at the conclusion of their initial tumor resection. RESULTS: A total of 84 patients in the gelatin film group were compared to 86 patients in the nongelatin film group. Patient age, sex, tumor pathology, tumor volume, tumor eloquence, laterality of surgical approach, history of radiotherapy, and time interval between resections did not differ between groups. Radiographic evidence of cortical ischemia following reoperation was less prevalent in the gelatin film group (13.1% vs 32.6%; P < .01). In multivariate logistic regression analysis, no gelatin film (P < .01) and larger tumor size (P = .02) predicted cortical surface ischemia following revision craniotomy. Postoperative complications in the gelatin film and nongelatin film group otherwise did not differ. CONCLUSION: Routine placement of commercially available sterile gelatin film on the cortex prior to dural closure is associated with decreased surgically induced tissue ischemia at the time of revision tumor craniotomy.

Mechanical Properties of the Cranial Meninges: A Systematic Review.

The meninges are membranous tissues that are pivotal in maintaining homeostasis of the central nervous system. Despite the importance of the cranial meninges in nervous system physiology and in head injury mechanics, our knowledge of the tissues' mechanical behavior and structural composition is limited. This systematic review analyzes the existing literature on the mechanical properties of the meningeal tissues. Publications were identified from a search of Scopus, Academic Search Complete, and Web of Science and screened for eligibility according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The review details the wide range of testing techniques employed to date and the significant variability in the observed experimental findings. Our findings identify many gaps in the current literature that can serve as a guide for future work for meningeal mechanics investigators. The review identifies no peer-reviewed mechanical data on the falx and tentorium tissues, both of which have been identified as key structures in influencing brain injury mechanics. A dearth of mechanical data for the pia-arachnoid complex also was identified (no experimental mechanics studies on the human pia-arachnoid complex were identified), which is desirable for biofidelic modeling of human head injuries. Finally, this review provides recommendations on how experiments can be conducted to allow for standardization of test methodologies, enabling simplified comparisons and conclusions on meningeal mechanics.

Minimizing CSF Leak and Wound Complications in Tethered Cord Surgery with Prone Positioning: Outcomes in 350 Patients.

BACKGROUND: We document the results of a protocol to reduce the incidence of cerebrospinal fluid (CSF) leak and other wound complications in patients undergoing tethered cord surgery (TCS). METHODS: Data from all patients undergoing TCS between January 2009 and April 2019 were reviewed retrospectively. Diagnosis (high risk or low risk; based on the presence of fascial and dural defects at surgery), type of graft used for dural or fascial repair, and CSF leak and other wound complications in the postoperative period were noted. All patients were nursed in the prone position with elevation of the foot end of the bed (Trendelenburg position) for at least 5 days after surgery with a subfascial drain in place. RESULTS: Of a total of 350 patients (191 high risk; 159 low risk), CSF leak from the wound was noted in 16 (4.5%). All but 4 of these patients were managed with wound suturing with or without insertion of a subcutaneous drain with continued nursing in the prone and Trendelenburg position. Two patients had meningitis and 3 patients had wound infection. Multivariate analysis revealed that the use of synthetic grafts (P < 0.000) and inability to close the dura (P = 0.02) were the only significant risk factors for CSF wound leak. Wound infections and/or dehiscence were noted in 17 (4.8%) other patients. CONCLUSION: Postoperative prone nursing with Trendelenburg position minimizes the incidence of CSF leak and other wound complications.

Comparing the results of duraplasty using amniotic membrane versus pericranium as dural graft; concerning CSF leakage and pseudomeningocele.

Purpose: In many brain surgeries, dura cannot be primarily repaired and it is necessary to use a graft. Appropriate repair of dura plays a major role in preventing CSF leakage and meningitis. In the cases where sufficient Pericranium is not available for recovery, we need to use graft from other resources. The present study compares the results of amniotic membrane dural graft and pericranium dural graft in terms of CSF leakage and Pseudomeningocele. Materials and methods: This is a semi-empirical research. Thirty cases underwent dural graft with amnion membrane because of inadequate local pericranium for repair. There were 30 other historical cases that had undergone auto-graft dural graft with Pericranium in the same center.Results: The average age of the participants in Pericranium graft group (P, n = 30) and those in amniotic graft group (A, n = 30) was 39.1 ± 15 and 43.9 ± 19 years old, respectively. As for the P and A groups, there were 14 and 17 males, respectively. Two cases of CSF leakage (7%) were observed in P group, while none was reported in A group. There were 3 cases (10%) of meningitis in Pericranium group and 2 cases (7%) were reported in amnion group. Out of 2 cases of meningitis in group P, 2 cases were associated with CSF leak. 5 cases of Hydrocephalus (17%) were observed in group P and 9 cases (30%) were reported in group A. No significant difference was observed between the two groups in any complication. The frequency of hydrocephalus was significantly higher in posterior fossa craniotomy.Conclusion: Amniotic membrane may provide a good source for cases with a large dural defect and can be utilized for all ages. Of course, its application in cases of posterior fossa craniotomy needs to be carefully studied so that the best results may be obtained.

Dural Repair in Cranial Surgery Is Associated with Moderate Rates of Complications with Both Autologous and Nonautologous Dural Substitutes.

OBJECTIVE: Duraplasty, a common neurosurgical intervention, involves synthetic or biological graft placement to ensure dural closure. The objective of this study is to advance our understanding of the use of dural substitutes in cranial surgery. METHODS: The PubMed database was systematically searched to identify studies published over the past decade (2007-2017) that described duraplasty procedures. Clinical data were disaggregated and analyzed for the comparisons of biological versus synthetic grafts. RESULTS: A total of 462 cases were included in the quantitative synthesis. Overall, the most common indication for duraplasty was tumor resection (53%). Allografts were more frequently used in decompression for Chiari malformations compared with xenografts and synthetic grafts (P < 0.001). Xenografts were more frequently used in decompressive hemicraniectomy procedures for evacuation of acute subdural hematomas over allografts and synthetics (P < 0.001). Synthetic grafts were more frequently used in tumor cases than biological grafts (P = 0.002). The cumulative complication rate for dural substitutes of all types was 11%. There were no significant differences in complication rates among the 3 types of dural substitutes. CONCLUSIONS: Dural substitutes are commonly used to ensure dural closure in a variety of cranial procedures. This study provides greater insight into duraplasty practices and highlights the moderate complication rate associated with the procedure. Future studies are needed to determine the safety and efficacy of such procedures in larger prospective cohorts.

The addition of duraplasty to posterior fossa decompression in the surgical treatment of pediatric Chiari malformation Type I: a systematic review and meta-analysis of surgical and performance outcomes.

OBJECTIVE Surgery is the definitive treatment of Chiari malformation Type I (CM-I). It involves posterior fossa decompression, which can be performed along with C-1 laminectomy, reconstructive duraplasty, or tonsil shrinkage. The aim of this study was to provide an updated systematic review and meta-analysis of the latest available evidence regarding posterior fossa decompression only (PFDO) versus posterior fossa decompression with duraplasty (PFDD) in the treatment of CM-I in children. METHODS A literature search was performed in compliance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for article identification, screening, eligibility, and inclusion. Relevant articles were identified from 6 electronic databases from their inception to April 2016. These articles were screened against established criteria for inclusion into this study. RESULTS From 12 relevant studies identified, 1492 pediatric patients treated via PFDD were compared with 1963 pediatric patients treated by PFDO for CM-I. PFDD was associated with greater overall clinical improvement (p = 0.009), along with longer length of stay (p < 0.0001) and more postoperative complications (p = 0.0001) compared with PFDO. No difference was observed between PFDD and PFDO in terms of revision surgery incidence (p = 0.13), estimated blood loss (p = 0.14), syrinx improvement (p = 0.09), or scoliosis improvement (p = 0.95). CONCLUSIONS It appears that the addition of duraplasty to posterior decompression in the definitive treatment of CM-I in children may alter surgical and performance outcomes. In particular, parameters of overall clinical improvement, length of stay, and postoperative complication may differ between children undergoing PFDD and those undergoing PFDO. Current evidence in the literature is of low to very low quality that, as of yet, has not been able to completely control for inherent selection bias both in study design and surgeon preference. Future, large prospective registries and randomized controlled trials are warranted to validate the findings of this study.

Fractura evolutiva: colocación de sistema derivativo cisto-peritoneal y corrección diferida: a propósito de un caso / Growing skull fracture: positioning system cisto-peritoneal derivative and correction deferred: report of a case

Describimos el caso de una paciente femenina de 5 años de edad, con antecedente de fractura craneal asociado a trauma directo en su segundo día de vida, posteriormente se diagnostica quistes porencefálico y aracnoideo frontoparietal izquierdo a los 3 meses de edad. Fue tratada en un primer momento con la colocación de sistema derivativo cistoperitoneal, y se le realizaron estudios de imágenes de seguimiento. A los 5 años de edad es traída a consulta de nuestro servicio de neurocirugía, por presentar deformidad calvarial en la superficie frontoparietal izquierda. El seguimiento con tomografía de cráneo demostró un cese relativo en la progresión en las dimensiones del quiste porencefálico y aumento del espacio entre los bordes óseos de la fractura. La paciente fue llevada a mesa operatoria, en la cual se realizó un abordaje hemicoronal izquierdo con resección de tejido gliótico, duroplastia con pericráneo y colocación de craneoplastía con tejido óseo craneal autólogo. El seguimiento al mes de la intervención correctiva mostró evolución satisfactoria y sin complicaciones. La cirugía correctiva de la fractura evolutiva, debe realizarse en el momento del diagnóstico para evitar su expansión. En concordancia con la teoría de Moss, se observa aumento del espacio entre los bordes de la fractura, aún con la disminución de la presión intracraneal al derivar el líquido cefalorraquídeo. En este caso, la intervención correctiva de la fractura, determinó una evolución satisfactoria, en ausencia de hidrocefalia o crisis convulsiva, posiblemente debida a la presión disminuida del quiste porencefálico sobre el parénquima subyacente.

We describe the case of a female patient of five years old, with a history of a skull fracture associated with direct trauma on his second day of life, then porencephalic left frontoparietal arachnoid cysts was diagnosed at 3 months of age. She was iniatially treated by plaing cystoeritoneal derivative system and follow-up imaging studies was performed. At 5 years of age is brought to clinic in our departmen of neurosurgery, for presenting calvarial deformity in the left frontoparietal area. The follow-p scan of the head showed a cease progression relative dimensions porencephalic cyst an increased space between the bone edges of the fracture. The patient was transferred to operating table, on which a hemicoronal left gliotico approach with resection of tissue was performed with dural graft placement craneoplasty bone tissue. Monitoring the month showed satisfactory corrective intervention and hassle evolution was performed with dural graft placement craneoplasty scalp and skull with autologous bone tissue. Corrective surgery of evolutionary fracture should be performed at the time of diagnosis to prevent its expansion. In agreement with the Moss theory, increasing the space between the edges of the fracture even with decreasing intracranial pressure deriving the cerebrospinal fluid was observed. In this case corrective intervention of the fracture produced a satisfactory outcome in the absence of hydrocephalus or seizure, possibly due to decreased pressure of porencephalic cyst on the underlying parenchyma.

Partial glossectomy and floor of mouth (FOM) defect repair with biological dural graft: A case report.

INTRODUCTION: Oral carcinoma can cause significant defects that would necessitate a challenging reconstructive surgery. These techniques include biological or synthetic dressings, grafts, regional flaps, and free-vascularized flaps. Among these, the dural graft has demonstrated promising results in repairing the skull-base defects. Our aim is to report a new, innovative technique for partial glossectomy and floor of mouth defect repair using a biological dural graft dressing when primary repair was not feasible and the patient did not consent to dermal graft or flap interventions. PRESENTATION OF CASE: This article reports the outcomes from a novel intervention of partial glossectomy repair using a biological dural dressing derived from bovine type-I collagen in a 57-year-old female patient with recurrent T1N1M0 squamous cell carcinoma of the left-sided tongue during the 12 month period of follow-up. DISCUSSION: The best option for large tongue defects is a free flap, while for a moderate defect is a regional oral flap. The biological graft, as an acellular dermal graft has been well known to facilitate secondary healing in the tongue as an alternative to the split-thickness skin graft. In the current study, the dural dressing in tongue reconstruction was likewise shown to be an effective biological dressing; hence, the collagen membrane is biologically acceptable to the oral mucosa and an excellent wound graft material. However, it is absolutely contraindicated in bovine hypersensitive patients. CONCLUSION: The biological dural graft dressing appears to be an effective method for tongue reconstruction, as it promotes adequate wound healing and it preserves function.

Postoperative epidural hematoma contributes to delayed upper cord tethering after decompression of Chiari malformation type I.

BACKGROUND: Symptomatic arachnoiditis after posterior fossa surgical procedures such as decompression of Chiari malformation is a possible complication. Clinical presentation is generally insidious and delayed by months or years. It causes disturbances in the normal flow of cerebrospinal fluid and enlargement of a syrinx cavity in the upper spinal cord. Surgical de-tethering has favorable results with progressive collapse of the syrinx and relief of the associated symptoms. CASE DESCRIPTION: A 30-year-old male with Chiari malformation type I was treated by performing posterior fossa bone decompression, dura opening and closure with a suturable bovine pericardium dural graft. Postoperative period was uneventful until the fifth day in which the patient suffered intense headache and progressive loose of consciousness caused by an acute posterior fossa epidural hematoma. It was quickly removed with complete clinical recovering. One year later, the patient experienced progressive worsened of his symptoms. Upper spinal cord tethering was diagnosed and a new surgery for debridement was required. CONCLUSIONS: The epidural hematoma compressing the dural graft against the neural structures contributes to the upper spinal cord tethering and represents a nondescribed cause of postoperative fibrosis, adhesion formation, and subsequent recurrent hindbrain compression.

Autologous dural substitutes: a prospective study.

OBJECTIVE: Duraplasty can be performed both by means of autologous tissues (such as galea-pericranium, temporal muscle, fascia lata) or by commercially available dural patches. Nowadays many neurosurgeons consider galea-pericranium duraplasty time-consuming, technically demanding or not adequate, thus dural surrogates are increasingly popular. In this prospective research we compared duraplasty using autologous galea-pericranium vs. dural patches in terms of postoperative long term results, ease/time required and costs. PATIENTS AND METHODS: Research has been designed as prospective cohort study, that included 185 patients undergoing supratentorial elective neurosurgery with galea-pericranium or non-autologous duraplasty (minimum follow-up 12 months). Variables taken into account were: wound infection, CSF fistula, subcutaneous CSF collection, bone flap osteitis, brain abscess, empyema and tardive wound dehiscence (particularly after postoperative radiotherapy). Time for galea-pericranium collection, size of galea-pericranium harvest and dural defects were recorded in each case. Costs for non-autologous duroplasty were calculated. RESULTS: No statistically significant differences were evident in long term postoperative results between the two groups. Mean time of galea-pericranium collection is less than 2min and enough galea-pericranium can be harvested in supratentorial approach to cover almost any dural defect. The only difference between the two groups is costs: an average of 268.7€/patient spent just for duraplasty. This figure is surely substantial if considered for the entire amount of surgeries performed in a department. CONCLUSIONS: Considering that in our study long term results are equivalent, that galea-pericranium duraplasty is feasible and rapid, our indications are in favor of saving a considerable amount of money since an ideal autologous dural substitute is available and "free".