Review of Cranioplasty after Decompressive Craniectomy

Paradoxical brain herniation following decompressive craniectomy: A case series and systematic review of literature

INTRODUCTION

Paradoxical brain herniation (PBH) represents a rare and potentially life-threatening complication observed in individuals following decompressive craniectomy. Its diagnosis necessitates a high level of suspicion, combined with clinical and imaging evidence, such as midline shift, herniation, and a decreased Glasgow Coma Scale (GCS). Given the rarity and severity of this condition, we conduct a comprehensive literature review to identify all documented predisposing factors, clinical presentations, and appropriate clinical management. This review will serve as a guide for effective treatment strategies.

CASE PRESENTATION

In this report, we document three cases of post-traumatic PBH following decompressive craniectomy. The patient's predisposing factor was a lumbar puncture, with two cases resolving after Terendlenburg repositioning, hydration, and elective cranioplasty. The third case developed PBH after external ventricular drainage (EVD) insertion. Although the patient's GCS improved after clamping the EVD and hydration, the patient ultimately succumbed to meningitis.

CLINICAL DISCUSSION

The primary clinical manifestations of PBH often encompass a diminished GCS alongside radiographic evidence of midline shift and brain herniation. Various precipitating factors have been associated with PBH after decompressive craniectomy, including CSF drainage, dehydration, and upright positioning, although instances of spontaneous PBH have been documented. Reported therapeutic strategies encompass rehydration, Trendelenburg positioning, temporary cessation of CSF drainage, and cranioplasty.

CONCLUSION

Given the infrequency of PBH and the potential for misdiagnosis with brain edema, it is imperative to consider this condition in every patient who experiences a decreased level of consciousness following decompressive craniectomy.

Decompressive Craniectomy: From Ancient Practices to Modern Neurosurgery

Decompressive craniectomy (DC) is a neurosurgical strategy that expels a parcel of the cranium to relieve pressure on a swollen or herniating brain. This review article explores the history of DC, from its ancient roots in trepanning to its contemporary applications. It then examines the mechanisms by which DC reduces intracranial pressure (ICP) and improves cerebral blood flow. The article highlights the efficacy of DC in treating patients with severe traumatic brain injury (TBI), stroke, and other conditions that cause increased ICP. However, it also acknowledges the potential complications of DC, such as infection and bleeding. The ethical considerations surrounding DC are explored in detail, particularly the challenging decision-making process for patients who are unable to give consent. A specific focus is given to the use of DC in pediatric patients, where the developing brain is especially vulnerable to pressure changes.

An Intact Periosteum is Required for Recombinant Human Jagged1 Guided Bone Regeneration in Calvaria Critical-size Defect Healing

The need to promote calvaria bone healing as a consequence of injury or craniotomy is a major clinical issue. Previous reports tested recombinant human Jagged1 (rhJagged1) treatment for critical-size calvaria defects in the absence of periosteum, and this resulted in significant new bone formation. As the periosteum contributes to healing by serving as a source of progenitor cells, the present study aimed to examine whether significantly more bone is formed when the periosteum is intact for using rhJagged1 to treat critical-size parietal bone defects in mice. Fifteen healthy adult mice, 34 to 65 weeks of age, 26.9 to 48.2 g, were divided into different groups that compared the critical-size defects treated with either phosphate-buffered saline or rhJagged1 protein in either the presence or absence of periosteum. The results indicated that more bone was formed in the presence of periosteum when rhJagged1 is delivered [35% bone volume per tissue volume (BV/TV); P = 0.02] relative to nonperiosteum. Recombinant human Jagged1 protein delivered in the absence of periosteum had the next most new bone formed (25% BV/TV). Defects with phosphate-buffered saline delivered in the absence or presence of periosteum had the least new bone formed (15% and 18% BV/TV, respectively; P = 0.48). The results also show that rhJagged1 does not form ectopic or hypertrophic bone. The usage of rhJagged1 to treat critical-size defects in calvaria is promising clinically, but to maximize clinical efficacy it will require that the periosteum be intact on the noninjured portions of calvaria.

Multidisciplinary Management of Skull Metastatic Follicular Thyroid Cancer in a Resource-Limited Setting

A 60-year-old woman presented to the Department of Surgery with an anterior neck mass and a mass on her left forehead. She was diagnosed with follicular thyroid cancer with metastasis to the skull, a rare presentation of follicular thyroid cancer that is associated with a poor prognosis. A multidisciplinary team evaluated the patient and devised a 3-staged surgical management plan: total thyroidectomy with central lymph node dissection, cranial metastasectomy, and cranioplasty with autologous split rib graft. This case illustrates how innovative multidisciplinary surgical management can be applied in a low-resource setting involving 3 surgical sub-specialties for the best possible outcome in a patient with metastatic follicular thyroid cancer.

Cisternostomy is not beneficial to reduce the occurrence of post-traumatic hydrocephalus in Traumatic Brain Injury

BACKGROUND

The Cisternostomy is a novel surgical concept in the treatment of Traumatic Brain Injury (TBI), which can effectively drain the bloody cerebrospinal fluid from the skull base cistern, reduce the intracranial pressure, and improve the return of bone flap, but its preventive role in post-traumatic hydrocephalus (PTH) is unknow. The purpose of this paper is to investigate whether Cisternostomy prevents the occurrence of PTH in patients with moderate and severe TBI.

METHODS

A retrospective analysis of clinical data of 86 patients with moderate and severe TBI from May 2019 to October 2021 was carried out in the Brain Trauma Center of Tianjin Huanhu Hospital. Univariate analysis was performed to examine the gender, age, preoperative Glasgow Coma Scale (GCS) score, preoperative Rotterdam CT score, decompressive craniectomy rate, intracranial infection rate, the incidence of subdural fluid, and incidence of hydrocephalus in patients between the Cisternostomy group and the non-Cisternostomy surgery group. we also analyzed the clinical outcome indicators like GCS at discharge,6 month GOS-E and GOS-E ≥ 5 in two groups.Additionaly, the preoperative GCS score, decompressive craniectomy rate, age, and gender of patients with PTH and non hydrocephalus were compared. Further multifactorial logistic binary regression was performed to explore the risk factors for PTH. Finally, we conducted ROC curve analysis on the statistically significant results from the univariate regression analysis to predict the ability of each risk factor to cause PTH.

RESULTS

The Cisternostomy group had a lower bone flap removal rate(48.39% and 72.73%, p = 0.024)., higer GCS at discharge(11.13 ± 2.42 and 8.93 ± 3.31,p = 0.000) and better 6 month GOS-E(4.55 ± 1.26 and 3.95 ± 1.18, p = 0.029)than the non-Cisternostomy group However, there was no statistical difference in the incidence of hydrocephalus between the two groups (25.81% and 30.91%, p = 0.617). Moreover, between the hydrocephalus group and no hydrocephalus group,there were no significant differences in the incidence of gender, age, intracranial infection, and subdural fluid. While there were statistical differences in peroperative GCS score, Rotterdam CT score, decompressive craniectomy rate, intracranial infection rate, and the incidence of subdural fluid in the two groups, there was no statistical difference in the percentage of cerebral cisterns open drainage between the hydrocephalus group and no hydrocephalus group (32.00% and 37.70%, p = 0.617). Multifactorial logistic binary regression analysis results revealed that the independent risk factors for PTH were intracranial infection (OR = 18.460, 95% CI: 1.864-182.847 p = 0.013) and subdural effusion (OR = 10.557, 95% CI: 2.425-35.275 p = 0.001). Further, The ROC curve analysis showed that peroperative GCS score, Rotterdam CT score and subdural effusion had good ACU(0.785,0.730,and 0.749), with high sensitivity and specificity to predict the occurrence of PTH.

CONCLUSIONS

Cisternostomy may decrease morbidities associated with removal of the bone flap and improve the clinical outcome, despite it cannot reduce the disability rate in TBI patients.Intracranial infection and subdural fluid were found to be the independent risk factors for PTH in patients with TBI,and the peroperative GCS score, Rotterdam CT score and subdural effusion had higher sensitivity and specificity to predict the occurrence of PTH. And more importantly, no correlation was observed between open drainage of the cerebral cisterns and the occurrence of PTH, indicating that Cisternostomy may not be beneficial in preventing the occurrence of PTH in patients with moderate and severe TBI.

Two-Stage Anatomic Myocutaneous Flap Dissection in Cranioplasty: Technical Nuances and Single-Surgeon Experience

BACKGROUND AND OBJECTIVES

Temporalis muscle management remains one of the most challenging aspects of cranioplasty, which accounts for considerable rates of dissection-related complications. Since 2019, the senior author has developed and consistently used a methodical, two-stage anatomic dissection technique to separate the scalp and temporalis muscle from the underlying brain. This technique is believed to facilitate dissection and minimize the risk of brain injury, while optimizing cosmetic outcomes.

METHODS

All patients who underwent cranioplasty between January 2019 and February 2023 were identified from a prospectively maintained database. Charts were retrospectively reviewed. Demographic, clinical, and procedural data were extracted and analyzed.

RESULTS

Twenty-nine patients, 20 men and 9 women with a median age of 37 years (range 17-72), were identified. Indications for craniectomy were traumatic brain injury in 18 (62.1%), hemorrhagic stroke in five (17.2%), ischemic stroke in four (13.8%), and aneurysmal subarachnoid hemorrhage in two (6.9%). Median precranioplasty modified Rankin Scale and Glasgow Coma Scale scores were 5 (range in series: 0-5) and 14 (range in series: 3-15), respectively. The median time to cranioplasty was 131 days (32-1717). Cranioplasty was technically successful in all patients, with a median operative time of 106 minutes (62-182). There were no intraoperative complications. Postoperative complications occurred in three patients (10.3%): hemorrhagic brain contusion (n = 1), meningitis (n = 1), and seizure (n = 1). Of those, one patient (3.4%) died 2 weeks after surgery from suspected pulmonary embolism. After a median follow-up of 4 months (1-44), all 28 survivors have either remained clinically stable or exhibited neurological improvement. Cosmetic results were good or excellent in 27 (96.4%) and fair in one (3.6%).

CONCLUSION

Two-stage anatomic dissection of the scalp and temporalis muscle during cranioplasty can maximize surgical efficiency and result in excellent outcomes. Cranioplasty should be considered a low-risk, low-complexity neurosurgical procedure. Safe and efficient management of the temporalis muscle is key.

Diagnostic, clinical management, and outcome of bone flap-related osteomyelitis after cranioplasty

OBJECTIVES

We aimed to describe diagnostic, management, and outcome of bone flap-related osteomyelitis after cranioplasty.

METHODS

Patients followed up in our tertiary care hospital for bone flap-related osteomyelitis after cranioplasty were included in a retrospective cohort (2008-2021). Determinants of treatment failure were assessed using logistic regression and Kaplan-Meier curves analysis.

RESULTS

The 144 included patients (81 [56.3%] males; median age 53.4 [interquartile range [IQR], 42.6-62.5] years) mostly presented wound abnormalities (n = 115, 79.9%). All infections were documented, the main pathogens being Staphylococcus aureus (n = 64, 44.4%), Cutibacterium acnes (n = 57, 39.6%), gram-negative bacilli (n = 40, 27.8%) and/or non-aureus staphylococci (n = 34, 23.6%). Surgery was performed in 140 (97.2%) cases, for bone flap removal (n = 102, 72.9%) or debridement with flap retention (n = 31, 22.1%), along with 12.7 (IQR, 8.0-14.0) weeks of antimicrobial therapy. After a follow-up of 117.1 (IQR, 62.5-235.5) weeks, 37 (26.1%) failures were observed: 16 (43.2%) infection persistence, three (8.1%) relapses, 22 (59.5%) superinfections and/or two (1.7%) infection-related deaths. Excluding superinfections, determinants of the 19 (13.4%) specific failures were an index craniectomy for brain tumor (odds ratio = 4.038, P = 0.033) and curettage of bone edges (odds ratio = 0.342, P = 0.048).

CONCLUSION

Post-craniectomy bone flap osteomyelitis are difficult-to-treat infection, necessitating prolonged antimicrobial therapy with appropriate surgical debridement, and advocating for multidisciplinary management in dedicated reference centers.

Low-Cost Wound Healing Protocol Reduces Infection and Reoperation Rates After Cranioplasty: A Retrospective Cohort Study

BACKGROUND AND OBJECTIVES

Cranioplasty infections are a common and expensive problem associated with significant morbidity. Our objective was to determine whether a wound healing protocol after cranioplasty reduced the rate of infections and to determine the value of this intervention.

METHODS

This is a single-institution retrospective chart review of 2 cohorts of cranioplasty patients over 12 years. The wound healing protocol, consisting of vitamin and mineral supplementation, fluid supplementation, and oxygen support, was instituted for all patients aged older than 15 years undergoing cranioplasty. We retrospectively reviewed the charts of all patients over the study period and compared outcomes before and after protocol institution. Outcomes included surgical site infection, return to operating room within 30 days, and cranioplasty explant. Cost data were collected from the electronic medical record. We included 291 cranioplasties performed before the wound healing protocol and 68 postprotocol.

RESULTS

Baseline demographics and comorbidities were comparable between preprotocol and postprotocol groups. Odds of takeback to operating room within 30 days were the same before and after the wound healing protocol (odds ratio [OR] 2.21 [95% CI 0.76-6.47], P = .145). Odds of clinical concern for surgical site infection were significantly higher in the preprotocol group (OR 5.21 [95% CI 1.22-22.17], P = .025). Risk of washout was higher in the preprotocol group (HR 2.86 [95% CI 1.08-7.58], P = .035). Probability of cranioplasty flap explant was also significantly higher in the preprotocol group (OR 4.70 [95% CI 1.10-20.05], P = .036). The number needed to treat to prevent 1 cranioplasty infection was 24.

CONCLUSION

A low-cost wound healing protocol was associated with reduced rate of infections after cranioplasty with concomitant reduction in reoperations for washout, saving the health care system more than $50,000 per 24 patients. Prospective study is warranted.

Clinical Outcomes After Cranioplasty With Titanium Mesh, Polyetheretherketone, or Composite Bone Cement: A Retrospective Study

Cranioplasty is a common neurosurgical procedure; however, the optimal material choice remains controversial. At the time of this writing, autologous bone, the preferred choice for primary cranioplasty, has a high incidence of complications such as infection and resorption, thus requiring frequent use of synthetic materials. Therefore, this study aimed to compare the clinical benefits of titanium mesh (Ti), polyetheretherketone (PEEK), and composite bone cement (CBC) in cranioplasty to provide a clear selection basis for clinicians and patients. This study retrospectively collected data from 207 patients who underwent cranioplasty with Ti (n=129), PEEK (n=54), and CBC (n=24) between January 2018 and December 2020 at Henan Provincial People's Hospital. Postoperative follow-up information after 6 months was used to compare the long-term effects of the 3 materials on the patients. There were no significant differences in the overall complication rate after cranioplasty among the 3 materials. However, subcutaneous effusion was more frequent with PEEK (24.07%) and CBC (20.83%) than with Ti (2.33%). Second, there were no significant differences in the increase in Glasgow Outcome Scale and Karnofsky Performance Status scores after cranioplasty among the 3 materials. Finally, we found that PEEK had the highest patient satisfaction and hospitalization cost, whereas the opposite was true for Ti. Although the surgical outcomes of the 3 implant materials were similar, an examination of clinical outcomes such as patient satisfaction showed significant differences, deepening people's perceptions of the 3 materials.

Severe Pediatric Open Skull Fracture With Exposed Brain Matter: A Case Report

Head trauma in the pediatric population carries a high rate of morbidity and mortality. The major causes of head trauma are related to falls, recreational activities, motor vehicle accidents, and gunshot wounds. Traumatic brain injury (TBI) can occur after severe head trauma and is defined as an alteration in brain function, or other evidence of brain pathology, caused by an external force. Intracranial edema and herniation are common consequences of a TBI in pediatric patients and are commonly relieved via decompressive craniectomy.  This case study describes a 13-year-old male presenting to the trauma center after an unhelmeted all-terrain vehicle (ATV) accident with a positive head strike and loss of consciousness. The evaluation revealed extensive skull fractures extending from the frontal to the occipital lobe with brain exposure. Computed tomography (CT) scan of the head demonstrated extensive, open skull fractures with significant displacement of the exposed brain, extensive bilateral parietal and frontal bone fractures, and bilateral temporal bone displaced fractures more extensive on the left. A bilateral hemicraniectomy was performed due to diffuse cerebral edema and a left frontal ventriculostomy was placed to monitor and manage intracranial pressure (ICP). It is believed that the unique presentation of an open skull fracture with an exposed brain acted as a decompressive method allowing for extreme lifesaving measures to be performed to save the patient. Further exploration is needed to truly understand the effects of the unique injury presentation and the role of an open fracture in the delay of increased ICP.

Anterolateral thigh adipofascial flap combined with skin paddle in three-dimension scalp reconstruction: A case report

INTRODUCTION AND IMPORTANCE

Management of cranial and scalp defects is always challenging. Complication rates following cranioplasty are still high (10-40 %), including bone graft resorption, infection, and T-mesh implant exposure due to thinning of soft tissue (Yeap et al., 2019; Alkhaibary et al., 2020; Cho and Kang, 2017 [1-3]).

CASE PRESENTATION

We present a case of a 38-year-old male with autologous bone graft resorption accompanied by thinning of the forehead skin. He underwent cranioplasty with titanium mesh (T-mesh) and scalp reconstruction with an anterolateral thigh (ALT) flap in a single-stage operation. A 2-component ALT flap was used: the skin paddle covered the scalp defect to reduce closure tension, and especially the adipofascial flap lining beneath the forehead skin to increase thickness. Postoperative results were great in terms of coverage function and aesthetics.

CLINICAL DISCUSSION

The phenomenon of soft tissue thinning causing titanium mesh exposure is a common complication with a rate of 10-14 % (Yeap et al., 2019; Dong et al., 2020; Maqbool et al., 2018 [1, 4, 5]). Using adipofascial ALT flap as a sub-scalp filler material has many advantages over the latissimus dorsi (LD) flap to increase scalp thickness but still ensure aesthetics.

CONCLUSION

The results suggest a new direction in using adipofascial ALT flap as filler material to increase scalp thickness to reduce T-mesh exposure following cranioplasty.

Sinking bone flap due to overdrainage of a ventriculoperitoneal shunt. A case report and review of the literature

The widespread use of decompressive craniectomy and subsequent cranioplasty has led to a better understanding of its complications. However, cases of a sunken bone flap have hardly ever been described. We present the eighth case reported up to date and perform a review of the literature of this sporadic complication. A 40-year-old Caucasian male suffered a traumatic brain injury that required a decompressive craniectomy. One month after initial trauma autologous cranioplasty was performed. A ventriculoperitoneal shunt was also placed. Neurological status progressively improved but his therapist noted cognitive status decline 8 months later. Follow-up computed tomography showed a progressive sinking bone flap. The patient underwent bone flap removal and a custom-made calcium phosphate-based implant was inserted, leading to symptoms resolution. Bone resorption has been described as the main cause of sinking bone flap following cranioplasty. This entity may manifest with symptoms of overdrainage in patients with cerebrospinal fluid shunt devices.

Repair of Cranial Defects in Rabbits with 3D-Printed Hydroxyapatite/Polylactic Acid Composites

Objective

The safety and efficacy of three-dimensional- (3D-) printed hydroxyapatite/polylactic acid (HA-PLA) composites in repairing cranial defects were evaluated in a rabbit experimental model.

Methods

Twelve New Zealand rabbits were selected as experimental subjects. Two holes (A and B), each with a diameter of approximately 1 cm, were made in the cranium of each rabbit. Hole A served as the experimental manipulation, and hole B served as the control manipulation. A 3D-printed HA-PLA composite was used for placement onto hole A, whereas autologous bone powder was used for placement onto hole B. Samples from the experimental holes and the control holes were collected at 30 and 90 days after surgery. The obtained materials were examined in terms of their morphologies and histopathologies and were also subjected to simultaneous hardness tests.

Results

Both the 3D-printed HA-PLA composite and autologous bone powder were able to repair and fill the cranial defects at 30 days and 90 days after surgery. At 30 days after surgery, the microhardness of the area repaired by the HA-PLA composite was lower than that of the area repaired by autogenous bone powder (p < 0.01), but neither of these treatments reached the hardness of normal bone at this time (p < 0.01). At 90 days after surgery, there was no statistically significant difference in the microhardness of the repaired area from the 3D-printed HA-PLA composite compared with that of the repaired area from autologous bone powder (p > 0.05), and there was no statistically significant difference in the hardness of the two repaired areas compared with that of the normal bone (p > 0.05). Hematoxylin-eosin staining showed that bone cells in the HA-PLA material in the experimental group grew and were arranged in an orderly manner. Bone trabeculae and marrow cavities were formed on the pore surface and inside of the HA-PLA scaffold, and the arrangement of bone trabeculae was regular.

Conclusion

3D-printed HA-PLA composites can induce bone regeneration, are biocompatible, have the same strength as autologous bone powder, are able to degrade, and are ultimately safe and effective for repairing cranial defects in rabbits. However, further research is needed to determine the feasibility of 3D-printed HA-PLA composites in human cranioplasty.

Tissue Expanders in Staged Calvarial Reconstruction: A Systematic Review

Cranioplasties are common procedures in plastic surgery. The use of tissue expansion (TE) in staged cranioplasties is less common. We present two cases of cranioplasties with TE and systematically review literature describing the use of TE in staged cranioplasties and postoperative outcomes. A systematic review was performed by querying multiple databases. Eligible articles include published case series, retrospective reviews, and systematic reviews that described use of TE for staged bony cranioplasty. Data regarding study size, patient demographics, preoperative characteristics, staged procedure characteristics, and postoperative outcomes were collected. Of 755 identified publications, 26 met inclusion criteria. 85 patients underwent a staged cranioplasty with TE. Average defect size was 122 cm ² , and 30.9% of patients received a previous reconstruction. Average expansion period was 14.2 weeks. The most common soft tissue closures were performed with skin expansion only (75.3%), free/pedicled flap (20.1%), and skin graft (4.7%). The mean postoperative follow-up time was 23.9 months. Overall infection and local complication rates were 3.53 and 9.41%, respectively. The most common complications were cerebrospinal fluid leak (7.1%), hematoma (7.1%), implant exposure (3.5%), and infection (3.5%). Factors associated with higher complication rates include the following: use of alloplastic calvarial implants and defects of congenital etiology ( p  = 0.023 and 0.035, respectively). This is the first comprehensive review to describe current practices and outcomes in staged cranioplasty with TE. Adequate soft tissue coverage contributes to successful cranioplasties and TE can play a safe and effective role in selected cases.

Next-generation personalized cranioplasty treatment

Decompressive craniectomy (DC) is a surgical procedure, that is followed by cranioplasty surgery. DC is usually performed to treat patients with traumatic brain injury, intracranial hemorrhage, cerebral infarction, brain edema, skull fractures, etc. In many published clinical case studies and systematic reviews, cranioplasty surgery is reported to restore cranial symmetry with good cosmetic outcomes and neurophysiologically relevant functional outcomes in hundreds of patients. In this review article, we present a number of key issues related to the manufacturing of patient-specific implants, clinical complications, cosmetic outcomes, and newer alternative therapies. While discussing alternative therapeutic treatments for cranioplasty, biomolecules and cellular-based approaches have been emphasized. The current clinical practices in the restoration of cranial defects involve 3D printing to produce patient-specific prefabricated cranial implants, that provide better cosmetic outcomes. Regardless of the advancements in image processing and 3D printing, the complete clinical procedure is time-consuming and requires significant costs. To reduce manual intervention and to address unmet clinical demands, it has been highlighted that automated implant fabrication by data-driven methods can accelerate the design and manufacturing of patient-specific cranial implants. The data-driven approaches, encompassing artificial intelligence (machine learning/deep learning) and E-platforms, such as publicly accessible clinical databases will lead to the development of the next generation of patient-specific cranial implants, which can provide predictable clinical outcomes. STATEMENT OF SIGNIFICANCE: Cranioplasty is performed to reconstruct cranial defects of patients who have undergone decompressive craniectomy. Cranioplasty surgery improves the aesthetic and functional outcomes of those patients. To meet the clinical demands of cranioplasty surgery, accelerated designing and manufacturing of 3D cranial implants are required. This review provides an overview of biomaterial implants and bone flap manufacturing methods for cranioplasty surgery. In addition, tissue engineering and regenerative medicine-based approaches to reduce clinical complications are also highlighted. The potential use of data-driven computer applications and data-driven artificial intelligence-based approaches are emphasized to accelerate the clinical protocols of cranioplasty treatment with less manual intervention and shorter intraoperative time.

Complications associated with early cranioplasty for patients with traumatic brain injury: a 25-year single-center analysis

OBJECTIVE

Cranioplasty is a technically simple procedure, although one with potentially high rates of complications. The ideal timing of cranioplasty should minimize the risk of complications, but research investigating cranioplasty timing and risk of complications has generated diverse findings. Previous studies have included mixed populations of patients undergoing cranioplasty following decompression for traumatic, vascular, and other cerebral insults, making results challenging to interpret. The objective of the current study was to examine rates of complications associated with cranioplasty, specifically for patients with traumatic brain injury (TBI) receiving this procedure at the authors' high-volume level 1 trauma center over a 25-year time period.

METHODS

A single-institution retrospective review was conducted of patients undergoing cranioplasty after decompression for trauma. Patients were identified and clinical and demographic variables obtained from 2 neurotrauma databases. Patients were categorized into 3 groups based on timing of cranioplasty: early (≤ 90 days after craniectomy), intermediate (91-180 days after craniectomy), and late (> 180 days after craniectomy). In addition, a subgroup analysis of complications in patients with TBI associated with ultra-early cranioplasty (< 42 days, or 6 weeks, after craniectomy) was performed.

RESULTS

Of 435 patients identified, 141 patients underwent early cranioplasty, 187 patients received intermediate cranioplasty, and 107 patients underwent late cranioplasty. A total of 54 patients underwent ultra-early cranioplasty. Among the total cohort, the mean rate of postoperative hydrocephalus was 2.8%, the rate of seizure was 4.6%, the rate of postoperative hematoma was 3.4%, and the rate of infection was 6.0%. The total complication rate for the entire population was 16.8%. There was no significant difference in complications between any of the 3 groups. No significant differences in postoperative complications were found comparing the ultra-early cranioplasty group with all other patients combined.

CONCLUSIONS

In this cohort of patients with TBI, early cranioplasty, including ultra-early procedures, was not associated with higher rates of complications. Early cranioplasty may confer benefits such as shorter or fewer hospitalizations, decreased financial burden, and overall improved recovery, and should be considered based on patient-specific factors.

Low-Cost Cranioplasty-A Systematic Review of 3D Printing in Medicine

The high cost of biofabricated titanium mesh plates can make them out of reach for hospitals in low-income countries. To increase the availability of cranioplasty, the authors of this work investigated the production of polymer-based endoprostheses. Recently, cheap, popular desktop 3D printers have generated sufficient opportunities to provide patients with on-demand and on-site help. This study also examines the technologies of 3D printing, including SLM, SLS, FFF, DLP, and SLA. The authors focused their interest on the materials in fabrication, which include PLA, ABS, PET-G, PEEK, and PMMA. Three-dimensional printed prostheses are modeled using widely available CAD software with the help of patient-specific DICOM files. Even though the topic is insufficiently researched, it can be perceived as a relatively safe procedure with a minimal complication rate. There have also been some initial studies on the costs and legal regulations. Early case studies provide information on dozens of patients living with self-made prostheses and who are experiencing significant improvements in their quality of life. Budget 3D-printed endoprostheses are reliable and are reported to be significantly cheaper than the popular counterparts manufactured from polypropylene polyester.

Materials Used in Cranial Reconstruction: A Systematic Review and Meta-Analysis

BACKGROUND

Cranioplasty is a common neurological procedure with complication rates ranging from 20% to 50%. It is hypothesized that the risks of various complications are impacted by which material is used for cranioplasty.

OBJECTIVE

To evaluate existing literature comparing rates of complications following cranioplasty using different materials including autologous bone, hydroxyapatite, methyl methacrylate (MMA), demineralized bone matrix, polyetheretherketone, titanium, or composite materials.

METHODS

PubMed/MEDLINE database was searched for relevant articles published between 2010 and 2020. After screening, 35 articles were included. Outcomes included infection, wound problems, poor cosmesis, overall complications, duration of surgery, and length of stay. For each outcome, a frequentist network meta-analysis was conducted to compare materials used.

RESULTS

The risk of infection was 1.62 times higher when MMA was used compared to autologous bone (RR 1.62, 95% CI 1.07 to 2.45). Length of stay following cranioplasty was on average 3.62 days shorter when titanium was used compared autologous bone (95% CI -6.26 to -0.98). The networks constructed for other outcomes demonstrated moderate to substantial between-study heterogeneity, wide confidence intervals, and no significant differences between materials.

CONCLUSIONS

The quality of existing literature on this topic is relatively poor, almost exclusively comprised of single-center retrospective studies. There is currently not strong enough evidence available to make comprehensive conclusions regarding the risk-profiles of various cranioplasty materials across multiple outcomes. Prospective randomized trials are necessary to confirm the significant results found in this analysis and to further elucidate the differential risks of various cranioplasty materials.

Basal Cisternostomy for Severe TBI: Surgical Technique and Cadaveric Dissection

Introduction

Cisternostomy is emerging as a novel surgical technique in the setting of severe brain trauma. Different surgical techniques have been proposed with a variable degree of epidural bone work. We present here the surgical technique as it is currently performed in our Institution.

Methods

Anatomical dissection of one adult cadaveric head, injected and non-formalin fixed was perfomed. A large right fronto-temporo-parietal craniotomy was accomplished. Extradural sphenoidal drilling till opening of the superior orbital fissure was performed. The microsurgical anatomy of basal cisternostomy was then explored.

Results

A step by step description of the surgical technique, enriched with cadaveric and intraoperative images, was made.

Conclusion

Basal cisternostomy is a promising surgical technique that does not necessarily include complex surgical maneuvers. Trained neurosurgeon can safely implement it in their clinical practice.

Customized cost-effective polymethylmethacrylate cranioplasty: a cosmetic comparison with other low-cost methods of cranioplasty

BACKGROUND

Intraoperative hand-moulded cranioplasty and polymethylmethacrylate (PMMA) prostheses made from bone impressions are economical but the cosmetic results are less than satisfactory. Commercially available customized prostheses perform better but are prohibitively expensive. We evaluate the performance of a locally developed, low-cost customized PMMA cranioplasty prosthesis.

OBJECTIVE

To compare the cosmetic outcome of 3 types of PMMA cranioplasty as well as with objective measurements on postoperative CT scans METHODS: This study includes 70 patients who underwent cranioplasty between March 2016 and June 2020. In this period, patients had their cranioplasty prostheses made by intra-operative hand moulding (HM), by using the removed bone as a template and making a bone impression (BI) or by 3D printing the prosthesis based on a CT scan. Cosmetic outcomes were assessed by the patient and the operating surgeon on an 8-point scale. The degree of measured anthropometric asymmetry was measured on a postoperative CT scan and correlated with the cosmetic outcome.

RESULTS

Our locally produced 3D-printed cranioplasty prostheses showed a statistically better performance in cosmetic scores when compared to the HM and BI (p value < 0.001). CT anthropometric measurements significantly correlated with cosmetic outcome (p value 0.01) CONCLUSION: Our 3D cranioplasty prostheses had better cosmetic outcomes than HM and BI prostheses, and our technique is able to produce them at 10% of the cost of the currently available commercial customized prostheses.

A Narrative Review of Cell-Based Approaches for Cranial Bone Regeneration

Current cranial repair techniques combine the use of autologous bone grafts and biomaterials. In addition to their association with harvesting morbidity, autografts are often limited by insufficient quantity of bone stock. Biomaterials lead to better outcomes, but their effectiveness is often compromised by the unpredictable lack of integration and structural failure. Bone tissue engineering offers the promising alternative of generating constructs composed of instructive biomaterials including cells or cell-secreted products, which could enhance the outcome of reconstructive treatments. This review focuses on cell-based approaches with potential to regenerate calvarial bone defects, including human studies and preclinical research. Further, we discuss strategies to deliver extracellular matrix, conditioned media and extracellular vesicles derived from cell cultures. Recent advances in 3D printing and bioprinting techniques that appear to be promising for cranial reconstruction are also discussed. Finally, we review cell-based gene therapy approaches, covering both unregulated and regulated gene switches that can create spatiotemporal patterns of transgenic therapeutic molecules. In summary, this review provides an overview of the current developments in cell-based strategies with potential to enhance the surgical armamentarium for regenerating cranial vault defects.

Different materials of cranioplasty for patients undergoing decompressive craniectomy: A protocol for systematic review and network meta-analysis

BACKGROUND

Cranioplasty is widely applied on patients who has undergone decompress craniectomy (DC) due to intractable increased intracranial pressure and the cranioplasty materials have been on the bleeding edge of biomolecular and material science. This systematic review and network meta-analysis (NMA) will be conducted to comprehensively evaluate the safety and efficacy of different cranial implants for patients with cranial defects due to various reasons.

METHODS AND ANALYSIS

This protocol has been reported following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. The following electronic databases will be searched from the date of database establishment to September 1, 2020: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, VIP, and Wanfang. Randomized controlled trials and non-randomized prospective studies focus on cranial implants will be included. Quality assessment will be conducted using Cochrane Collaboration's tool or risk of bias in nonrandomized studies of interventions based on their study designs. The primary outcome will be postoperative early mortality and implant failure while various complications for secondary outcomes. Pairwise and network meta-analysis will be conducted using STATA V.14 (StataCorp, College Station, Texas, USA). Subgroup analyses and sensitivity analyses will be conducted to assess the robustness of the results.

ETHICS AND DISSEMINATION

This systematic review does not require an ethics approval or the need to obtain informed consent. The results will be published in a peer-reviewed scientific journal.

PROTOCOL REGISTRATION NUMBER

INPLASY 202110001.

Quantitative assessment and localization of the hollowing of the temple after craniectomy and cranioplasty-The frontozygomatic shadow

Background

After cranioplasty, in many cases a not negligible soft tissue defect remains in the temporozygomatical area, also referred to as a hollowing defect of the temple.

Objective

To assess the precise localization and volume of the hollowing defect, to optimize future cranioplasties.

Methods

CT data of patients who received craniectomy and conventional CAD cranioplasty in our institution between 2012 and 2018 were analyzed. CT datasets prior to craniectomy and after cranioplasty were subtracted to quantify the volume and localization of the defect.

Results

Out of 91 patients, 21 had suitable datasets. Five cases had good cosmetic results with no defect visible, 16 patients had an apparent hollowing defect. Their average defect volume was 5.0 cm³ ± 4.5 cm³. The defect localizations were in the area behind the zygomatic process and just below the superior temporal line, covering an area of app. 3x3 cm². Surgical attempts of temporal muscle restoration were more often found in reports of good results (p<0.01), but also in 50% of reports, whose surgeries resulted in hollowing of the temple. Mean time between the two surgeries was 112 ± 43 days. No significant differences between patients with and without hollowing defect were detected regarding time between the two surgeries, age or performing surgeon.

Conclusion

This work supplies evidence for the indication of a surgical corrective during cranioplasty in the small but cosmetically relevant area of the “frontozygomatic shadow”. Based on our 3D data analysis, future focused surgical strategies may obtain better aesthetical results here.

Predictive Value of Swab Cultures for Cryopreserved Flaps During Delayed Cranioplasties

OBJECTIVE

To assess the predictive value of swab cultures of cryopreserved skull flaps during cranioplasties for surgical site infections (SSIs).

METHODS

A retrospective review was conducted of consecutive patients who underwent delayed cranioplasties with cryopreserved autografts between 2009 and 2017. The results of cultures obtained from swabs and infected surgical sites were assessed. The accuracy, sensitivity, and specificity of swab cultures for SSIs were evaluated.

RESULTS

The study included 422 patients categorized into two groups, swab and nonswab, depending on whether swab cultures were implemented during cranioplasties. The overall infection rate was 7.58%. No difference was seen in infection rates between groups. There were 18 false-positive and no true-positive swab culture results. All bacteria between swab cultures and SSI cultures were discordant. Meanwhile, there were 19 false-negative swab cultures. The results showed high specificity but low sensitivity for swab cultures to predict SSI occurrence and the pathogens.

CONCLUSIONS

Owing to low accuracy and sensitivity, swab cultures of cryopreserved autografts should not be routinely performed during delayed cranioplasties.

Syndrome of the Trephined and ParoxySmal Sympathetic Hyperactivity in a 17-year-old minimally conscious state patient: A Case Report

Purpose: Syndrome of the Trephined (SoT) is one of the most unknown complications of the Decompressive Craniectomy (DC) after Traumatic Brain Injury (TBI). A combination of neurological clinical criteria and radiological signs after DC is necessary to make its diagnosis. In our case, as the patient was in a minimally conscious state (MCS), it was impossible to clinically assess any neurological deterioration according to the criteria found in the literature. There is no description of clinical diagnostic criteria suitable for patients with MCS apart from the visible 'Skin Flap.'Method: A 17-year-old patient sustained a severe TBI. Two months after the TBI and a DC he exhibited an MCS with a Glasgow Coma Scale (GCS) of 7 and a Wessex Head Injury Matrix (WHIM) of 5. He presented several paroxysmal sympathetic hyperactivity (PSH) episodes a day and developed a sinking skin flap. A cranioplasty was performed. Then, we noticed the gradual disappearance of PSH episodes plus an improvement of the CRS and the WHIM. Results: The evolution of the WHIM data revealed a statistically significant difference (p 0.0047). Conclusion: Further studies should be conducted to assess whether the WHIM and the frequency of PSH episodes may be part of the diagnostic criteria for SoT in MCS patients.

The Materials Utilized in Cranial Reconstruction: Past, Current, and Future

BACKGROUND

Cranioplasty (CP) is associated with high complication rates compared to other common neurosurgical procedures. Several graft materials are used for CP, which may contribute to the high complication rates, but data in the literature regarding the influence of graft material on post-CP outcomes are inconsistent making it difficult to determine if, when, and to what extent the graft material impacts the rate of perioperative complications. There is an increased demand to identify and develop superior graft materials.

OBJECTIVE

To review and compare the indications, risks, complications, and patient results associated with the use of different graft materials for cranial reconstructions.

DESIGN

A search through EBSCOhost was conducted using the keywords "craniectomy" or "decompressive craniectomy," "cranioplasty," and "materials." The search was limited to literature published in the English language from 2005 until the present. Ultimately, 69 articles were included in this review. Due to the heterogeneity of the study populations, results, statistical analyses, and collecting methods, no statistical analyses could be performed.

CONCLUSIONS

Several graft materials have been adapted for use in cranial reconstructions with inconsistent results making it unclear if or when one material may be indicated over others. Advances in computer-aided design have led to improved patient-specific implants, but the ideal graft material is still being sought after in ongoing research efforts. Reviewing materials currently available, as well as those in clinical trials, is important to identify the limitations associated with different implants and to guide future research.

A New Type of Three-Dimensional Customized Composite Implant in Reconstruction of Large Skull Defects

ABSTRACT

Large skull defects can result in chronic injury to intracranial tissues as well as psychological trauma for patients, and their repair presents a challenge to surgeons. Hydroxyapatite has been used in reconstructing skull defects for many years, but it is difficult to adjust the shape and size of the material intraoperatively, especially for large defects. With three-dimensional digital technology, a new type of customized composite implant made of epoxide acrylate maleic and hydroxyapatite has been applied in clinical practice. In this retrospective review, 15 patients with large skull defects (4 female and 11 male, at a mean age of 36.4 years, range from 24-65 years) were treated with the novel customized composite implant, reconstructing the large skull defects successfully. During the average 2.2 years follow-up period (range 0.5-4 years), complications including infection, cerebrospinal fluid leakage, intracranial hemorrhage, or implant exposurea were not occured, only 1 patient (6.7%) with a seroma managed non-operatively. The customized implants, which required no intraoperative adjustments and are about a third of the cost of titanium implants, are an excellent alternative for large skull defect repair.

Split-Thickness Decompression in the Management of Intracranial Pressure

Surgical management of elevated intracranial pressures due to stroke or traumatic brain injury has classically been through decompressive craniectomy (DC). There is significant morbidity associated with DC including subdural hygromas, syndrome of the trephined, and the need for subsequent cranioplasty. Alternative techniques including the hinged and floating craniotomy have shown promise though can still suffer from complications associated with an unsecured bone flap. We report a case in which a patient who presented with an acute subdural hematoma and associated midline shift that was successfully treated with decompression via thinning and re-securing of the bone flap in a “split-thickness decompression.”

Spontaneous Cranial Bone Regeneration After a Craniectomy in an Adult

Spontaneous reossification is a very rare phenomenon following a large calvarial defect, particularly in adults. A 29-year-old woman with acute subdural hematoma and brain edema underwent emergent decompressive craniectomy and evacuation of hematoma. Follow-up examination 2 years later showed a well-formed bone along the craniectomy site. To our knowledge, this is the first case report with total spontaneous reossification in adults. A literature review is provided, and the physiology of the process is suggested. Pericranium, diploë, and, above all, dura mater collaborate in spontaneous bone formation. All these layers are very important, and they must be respected during dissection.

[Skull defect repair in children using a 3D-printing technology]

Currently, 3D-printing technologies are increasingly used in neurosurgery. Active development of this approach is valuable to improve preoperative planning, intraoperative navigation, and manufacturing of realistic training models. In this manuscript, the authors report an experience of the pediatric neurosurgical department of the Almazov National Medical Research Center regarding 3D-printing technologies in manufacturing of individual implants for skull defect closure. The main aspects of this technology, advantages and disadvantages are considered. Moreover, the authors describe several cases of creating individual implants for children with skull defects of various origins, dimensions and complexity.

A systematic review of cranioplasty material toxicity in human subjects

PURPOSE

Local and systemic toxic reactions to implanted materials can result in morbidities. However, little is reported about cranioplasty implants. Therefore, we performed a systematic review on the toxicity of different materials used for cranioplasty implants.

MATERIALS AND METHODS

A systematic search was conducted by browsing the Pubmed, Embase, and Cochrane Library databases. All human studies that identified toxic (aseptic) reactions to any types of material used as cranioplasty implants or onplants, published up to January 1, 2019, were included in the review.

RESULTS

Nineteen studies were identified. Collectively, 36 patients endured some type of toxic reaction to an implanted material. Eleven studies presented several types of toxicity for PMMA cranioplasties in several tissue types. One article highlighted the risk of neurotoxicity for PMMA cranioplasty. Three articles presented toxic reactions to calcium phosphate and titanium implants. Three additional articles presented toxic reactions to PEEK, polypropylene-polyester, and polyethylene.

CONCLUSION

All materials currently used for cranioplasty showed occasional toxicity and morbidities. Therefore, none can be considered completely biologically inert. We found that aseptic inflammatory reactions have been underreported in the literature due to a high incidence of infections with questionable evidence.

Postural neurologic deficits after decompressive craniectomy: A case series of sinking skin flap syndrome in traumatic brain injury

BACKGROUND

Hemicraniectomy to manage raised intracranial pressure following traumatic brain injury (TBI) has improved survival but may increase the incidence of Sinking Skin Flap Syndrome (SSFS). SSFS is a clinical syndrome in which patients with craniectomy develop objective neurologic abnormalities due to the pressure of the atmosphere on the unprotected brain, often presenting with postural headaches and neurologic deficits that localize to the craniectomy site. Previously thought to be a rare complication of craniectomy after TBI, evidence suggests SSFS is under-recognized.

OBJECTIVE

To describe the clinical and radiographic features leading to diagnosis and the impact of temporizing and definitive management of SSFS on outcomes in inpatients with moderate/severe TBI.

METHODS

Two patients' symptoms, qualitative behaviour observation, physical and cognitive outcome measures, and neuroimaging pre- and post-temporizing measures and cranioplasty are presented.

RESULTS

Both patients demonstrated partial improvements with temporizing measures and substantial improvements in functional, cognitive, physical, and rehabilitation outcomes from the cranioplasty and resolution of SSFS.

CONCLUSIONS

Rehabilitation care providers are critical to the timely diagnosis and management of SSFS, including the use of temporizing measures and advocacy for definitive treatment with cranioplasty. These cases highlight the diverse clinical presentations and importance of SSFS diagnosis to improve patient outcomes.

Super early cranial repair improves the prognosis of patients with craniocerebral injury

Objective

Craniocerebral injury has high disability and mortality rates. The timing of cranioplasty has an important impact on patients’ prognosis. This study was performed to compare the functional prognosis between super early repair and conventional repair.

Methods

This observational study included 60 patients who underwent cranioplasty after surgical treatment of severe craniocerebral trauma. The patients were divided into two groups according to the time of cranial repair after the surgical treatment of craniocerebral injury: the super early group and the conventional repair group. Sex, age, Karnofsky performance status (KPS) score, Zubrod performance status (ZPS) score, psychological function score, quality of life score, and complications were recorded.

Results

The KPS score, ZPS score, psychological function score, and quality of life score were significantly related to the intervention period. Each of these scores had a clear correlation with the performance of super early treatment.

Conclusion

Super early cranial repair does not increase the incidence of surgical complications, and it can improve the postoperative KPS, ZPS, and quality of life scores.

Concurrent Versus Staged Procedures for Ventriculoperitoneal Shunt and Cranioplasty: A 10-Year Retrospective Comparative Analysis of Surgical Outcomes

BACKGROUND

Many patients undergoing decompressive craniectomy will develop persistent hydrocephalus before cranioplasty. Therefore, surgeons must decide whether to perform ventriculoperitoneal shunt (VPS) placement and cranioplasty simultaneously or in staged procedures. With limited, conflicting data reported, this decision has often been made by personal preference. The objective of the present study was to compare the surgical outcomes between patients undergoing concurrent or staged VPS placement and cranioplasty.

METHODS

We performed a 10-year retrospective comparative analysis of patients who had undergone either simultaneous or staged VPS placement and cranioplasty at a tertiary academic medical center.

RESULTS

Of the 40 patients, 18 had undergone concurrent procedures and 22 had undergone VPS placement before a separate cranioplasty procedure. The concurrent group was significantly older, had more often had the VPS placed in the external ventricular drain site, and had had more patients taking aspirin at surgery. The rates of infection, resorption, and reoperation did not differ significantly, although reoperation showed a trend toward occurring less frequently in the concurrent group. Hospital-acquired infection occurred significantly less frequently in the concurrent patients. The rate of VPS-associated outcomes did not differ significantly between the 2 groups.

CONCLUSIONS

Because of the trend toward a reduced reoperation rate, the significantly reduced rate of hospital-acquired infection, and the reduction in the number of surgeries, we recommend that patients awaiting cranioplasty in the setting of persistent hydrocephalus undergo concurrent VPS placement and cranioplasty rather than staged procedures.

Latissimus Dorsi-Myocutaneous Flap in the Repair of Titanium Mesh Exposure and Scalp Defect After Cranioplasty

Titanium mesh was widely used for cranium defect repair but associated with high complication rates. In this study, the authors describe a method using latissimus dorsi-myocutaneous flap in the repair of titanium mesh exposure and scalp defect after cranioplasty, and the plate retaining is also achieved. Fifteen patients from April 2012 to May 2016 underwent this procedure, the age ranged from 32 to 62 years and 47 years old on average, and all the patient had plate exposure combined with surgical site infection and variation of scalp defect. All the patients had fully flap survive, and follow up ranged from 6 months to 24 months, 1 patient had titanium mesh re-expose and received additional operation to remove the plate. The free latissimus dorsi musculocutaneous flap could supply large size of bulky tissue coverage with good blood supply and strong anti-infection ability. This method was an option for retaining the titanium mesh and repairing the exposure for the mild infection with small size scalp defect patient.

Cranioplasty: A Comprehensive Review of the History, Materials, Surgical Aspects, and Complications

Cranioplasty is a common neurosurgical procedure performed to reconstruct cranial defects. The materials used to replace bone defects have evolved throughout history. Cranioplasty materials can be broadly divided into biological and synthetic materials. Biological materials can be further subdivided into autologous grafts, allografts, and xenografts. Allografts (bony materials and cartilage from cadavers) and xenografts (bony materials from animals) are out of favor for use in cranioplasty because of their high rates of infection, resorption, and rejection. In autologous cranioplasty, either the cranial bone itself or bones from other parts of the body of the patient are used. Synthetic bone grafts have reduced the operation time and led to better cosmetic results because of the advancement of computer-based customization and three-dimensional printing. Aluminum was the first synthetic bone graft material used, but it was found to irritate neural tissue, induce seizures, and dissolve over time. Acrylic, in the form of methyl methacrylate, is the most widely used material in cranioplasty. Hydroxyapatite is a natural component of bone and is believed to enhance bone repair, resulting in decreased tissue reactions and promoting good osteointegration. Polyetheretherketones are light and nonconductive and do not interfere with imaging modalities. The complication rates of cranioplasty are high, and surgical site infection is the most common complication. The effect of cranioplasty timing on cognitive function remains debatable. However, the timing of cranioplasty is independent of neurologic outcomes. In this article, the history, materials, complications, and evolution of current practices used in cranioplasty are comprehensively reviewed.

Does the skull Hounsfield unit predict shunt dependent hydrocephalus after decompressive craniectomy for traumatic acute subdural hematoma?

Background and purpose

Posttraumatic hydrocephalus affects 11.9%–36% of patients undergoing decompressive craniectomy (DC) after traumatic brain injury and necessitates a ventriculo-peritoneal shunt placement. As bone and arachnoid trabeculae share the same collagen type, we investigated possible connections between the skull Hounsfield unit (HU) values and shunt-dependent hydrocephalus (SDHC) in patients that received cranioplasty after DC for traumatic acute subdural hematoma (SDH).

Methods

We measured HU values in the frontal bone and internal occipital protuberance from admission brain CT. Receiver operating characteristic curve analysis was performed to identify the optimal cut-off skull HU values for predicting SDHC in patients receiving cranioplasty after DC due to traumatic acute SDH. We investigated independent predictive factors for SDHC occurrence using multivariable logistic regression analysis.

Results

A total of 162 patients (>15 years of age) were enrolled in the study over an 11-year period from two university hospitals. Multivariable logistic analysis revealed that the group with simultaneous frontal skull HU ≤797.4 and internal occipital protuberance HU ≤586.5 (odds ratio, 8.57; 95% CI, 3.05 to 24.10; P<0.001) was the only independent predictive factor for SDHC in patients who received cranioplasty after DC for traumatic acute SDH.

Conclusions

Our study reveals a potential relationship between possible low bone mineral density and development of SDHC in traumatic acute SDH patients who had undergone DC. Our findings provide deeper insight into the association between low bone mineral density and hydrocephalus after DC for traumatic acute SDH.

Predictors of Surgical Site Infection in Autologous Cranioplasty: A Retrospective Analysis of Subcutaneously Preserved Bone Flaps in Abdominal Pockets

BACKGROUND

Decompressive craniectomy (DC) is a surgical procedure performed to manage intracranial hypertension. Once performed, patients are obligated to undergo another surgical procedure known as cranioplasty to reconstruct the cranial defect. Cranioplasty still has one of the highest rates of infection. The factors contributing to the high rate of surgical site infection (SSI) after cranioplasty are not well established. This study aims to estimate the incidence of SSI and determine its possible risk factors for patients who underwent cranioplasty using bone flaps subcutaneously preserved in abdominal pockets.

METHODS

A retrospective cohort study was conducted to investigate the predictors of infection among patients who underwent cranioplasty from subcutaneously preserved bone flaps in abdominal pockets between January 2005 and December 2018 at a level l trauma center.

RESULTS

A total of 103 cases of cranioplasty from subcutaneously preserved bone flaps were included in the study. The mean age of the patients was 31.2 ± 14.8 years (range, 5-67 years). The median interval between DC and cranioplasty was 115 days. The most frequent indication for DC was traumatic brain injury (76.4%). The incidence of SSI was noted in 15.7% of patients. The most significant predictors of infection in patients requiring cranioplasty were blood glucose levels and skull defect size (P = 0.03 and P = 0.02, respectively).

CONCLUSIONS

Blood glucose levels and skull defect size were the only identifiable risk factors associated with SSI. Storing bone flaps in subcutaneous abdominal pockets is cost-efficient but carries considerable risk of infection.

Retrospective Chronologic Computed Tomography Analysis of Bone Flap Fusion and Resorption After Craniotomy and Autologous Cryopreserved Cranioplasty

BACKGROUND

In open brain surgery, fixation of the bone flap is the final procedure. The bone flaps then fuse naturally. The objective of this study was to investigate the chronological process of bone fusion after craniotomy and autologous cranioplasty.

METHODS

Retrospective data were collected from patients who underwent craniotomy or cranioplasty after August 2004 and had at least 1 computed tomography (CT) scan at 3 months postsurgery. The patients were divided into a craniotomy group and a cranioplasty group. Head CT scans were analyzed to evaluate bone fusion and resorption.

RESULTS

Records from 978 patients who underwent craniotomy or cranioplasty between September 2004 and November 2015 were reviewed; 369 patients were eligible for the final analysis (craniotomy, n = 276; cranioplasty, n = 93). The mean cryopreservation period for the bone flap in the cranioplasty group was 49.3 days. The mean patient age was 51.4 ± 18.1 years in the craniotomy group and 51.6 ± 17.1 years in the cranioplasty group. Head CT scans showed bone fusion rates of 76.6% in the craniotomy group and 53.3% in the cranioplasty group at 6 months postsurgery (P = 0.015) and 78.6% and 78.1%, respectively, at 1 year postsurgery (P = 0.951). There was also a significant difference in the bone flap resorption rate between the 2 groups.

CONCLUSIONS

Bone flap fusion rates after craniotomy and cranioplasty were significantly different before 12 months, but not significantly different thereafter. Bone resorption occurred more frequently in the cranioplasty group over time.

Using titanium mesh to replace the bone flap during decompressive craniectomy: A medical hypothesis

Decompressive craniectomy (DC) plays a significant role in treating refractory intracranial hypertension. During this surgical procedure, part of the skull is removed and the underlying dura mater is open, which can effectively release intracranial pressure. However, in some cases, the decision whether or not to remove the bone flap relies on the surgeon's personal experience. Positive decisions are usually made to avoid massive postoperative cerebral edema and infarction, which can lead to overtreatment. The procedure is related to many side-effects, which may affect the recovery of neurological function. Patients who have survived have to be anesthetized and undergo secondary cranioplasty 3 or 6 months later. Despite its technical simplicity, complications associated with cranioplasty are hard to ignore. Therefore, there is a need for a new surgical procedure combining decompressive craniectomy and cranioplasty. Acute expansion of the skin flap is limited, and the compensatory capacity of the skull after DC depends on the volume of the bone flap at the early stage. The titanium mesh is thin and strong, does not take up extra space provided by bone flap. Therefore, we put forward the concept of Decompressive Bone Flap Replacement. During this procedure, neurosurgeons resect the massive bone flap, open the dura mater, remove the hematoma in a similar manner to a standard craniotomy and then use titanium mesh shaped appropriately to replace the bone flap. Compared with traditional DC, it can ensure the integrity of the skull without affecting the effect of decompression. This paper presents 2 cases of DC and reviews the literature sustaining our hypothesis.

Two-Staged Frontal Bone Defect Reconstruction: Perioperative Assessment of Scalp Vascularization Using Near-Infrared Indocyanine Green Video Angiography (Visionsense Iridium)

BACKGROUND

Head trauma and neurosurgical-related osteomyelitis are common causes of cranial bone defect. Even though cranioplasty is considered a safe and well-consolidated procedure, there are still some issues about the flap's vascularization assessment. In this paper we describe a 2-staged cranioplasty procedure, focusing on the perioperative evaluation of the skin flap vascularization. Our goal is to assess if the skin flap's perfusion measurement with indocyanine green fluorescence can be considered a reliable method to predict good outcome in cranioplasties.

CASE DESCRIPTION

A 50-year-old patient presented with a wide frontal bone defect due to a prior surgery-related osteomyelitis. During the first operation, a tissue expander was placed under the scalp in order to grant an appropriate skin stretching. During the second operation the defect was repaired with a custom-made prosthesis after tissue expander removal. During all procedures, vascular integrity of the skin flap was intraoperatively assessed by means of indocyanine green fluorescence.

CONCLUSIONS

Surgical procedures were well tolerated; at 1 year of follow-up the cosmetic defect was unremarkable. Indocyanine green fluorescence can be a good aid to predict the probability of the skin flap survival by measuring its perfusion.

Cranioplasty: An Institutional Experience

Cranioplasty is a common procedure in neurosurgical practice, but associated with high complication rates. In the current study, the authors describe surgical characteristics and results of cranioplasty performed in a tertiary teaching hospital in Brazil. Data were obtained from electronic medical records of cranioplasties performed between January 2013 and November 2016. The sample comprised of 33 patients, and the mean follow-up time was 16 months. Patients presented most of the times a good preoperative status, with 84.8% of patients classified between 0 and 3 at modified Rankin scale and 78.7% with 4 or 5 points at Glasgow Outcome Scale. The most common initial diagnosis was vascular disease (48% of patients) followed by traumatic brain injury (36% of patients). The majority of cranioplasties used an autograft: the autologous bone flap removed during a previous surgery (craniectomy) and stored in the abdominal subcutaneous fat (67% of patients). In 3 patients, the polymethylmethacrylate prosthesis was custom-made prior to the operation using 3-dimensional printing, based on computed tomography images. Five patients (15% of patients) developed symptoms related to surgical site infection, manifesting at an average of 5 weeks following the procedure. Three of them presented scalp dehiscence before the infection symptoms. Cranioplasty should be performed early, as long as clinical conditions are good and the patient has overcome the acute phase of neurological injury.

Timing for cranioplasty to improve neurological outcome: A systematic review

INTRODUCTION

Cranioplasty is a surgical technique applied for the reconstruction of the skullcap removed during decompressive craniectomy (DC). Cranioplasty improves rehabilitation from a motor and cognitive perspective. However, it may increase the possibility of postoperative complications, such as seizures and infections. Timing of cranioplasty is therefore crucial even though literature is controversial. In this study, we compared motor and cognitive effects of early cranioplasty after DC and assess the optimal timing to perform it.

METHODS

A literature research was conducted in PubMed, Web of Science, and Cochrane Library databases. We selected studies including at least one of the following test: Mini-Mental State Examination, Rey Auditory Verbal Learning Test immediate and 30-min delayed recall, Digit Span Test, Glasgow Coma Scale, Glasgow Outcome Scale, Coma Recovery Scale-Revised, Level of Cognitive Functioning Scale, Functional Independence Measure, and Barthel Index.

RESULTS

Six articles and two systematic reviews were included in the present study. Analysis of changes in pre- and postcranioplasty scores showed that an early procedure (within 90 days from decompressive craniectomy) is more effective in improving motor functions (standardized mean difference [SMD] = 0.51 [0.05; 0.97], p-value = 0.03), whereas an early procedure did not significantly improve neither MMSE score (SMD = 0.06 [-0.49; 0.61], p-value = 0.83) nor memory functions (SMD = -0.63 [-0.97; -0.28], p-value < 0.001). No statistical significance emerged when we compared studies according to the timing from DC.

CONCLUSIONS

It is believed that cranioplasty performed from 3 to 6 months after DC may significantly improve both motor and cognitive recovery.