Fat embolism syndrome is a common occurrence after orthopedic trauma and surgery. Cerebral fat embolism (CFE) may arise after fat globules enter the arterial circulation. The neurological manifestations of CFE vary and generally carries a favorable outcome. A small number of reports exist regarding patients with CFE who experienced severe neurological deficits and significant edema on radiographic studies, and subsequently underwent decompressive hemicraniectomy (DHC), some of which had full neurological recoveries. Here, we present the case of a 21-year-old male who presented after a motorcycle accident with multiple orthopedic injuries, who after fixation did not awake from anesthesia. The patient was ultimately found to have cerebral fat emboli, and developed significant edema and swelling. The patient underwent DHC with subsequent cranioplasty and returned to his neurological baseline seven months after his initial injury. DHC for CFE has been described in a few cases with some patients have had substantive recoveries, including the present case. This case emphasizes the importance of promptly recognizing and reversing elevated intracranial pressures and the possibility of promising recoveries.

UNASSIGNED: Decompressive craniectomy and craniotomy are among the most common procedures in Neurosurgery. In recent years, increased attention has focused on the relationships between incision type, extent of decompression, vascular supply to the scalp, cosmetic outcomes, and complications. Here, we review the current literature on scalp incisions for large unilateral front-temporo-parietal craniotomies and craniectomies.
UNASSIGNED: Publications in the past 50 years on scalp incisions used for front-temporo-parietal craniectomies/craniotomies were reviewed. Only full texts were considered in the final analysis. A total of 27 studies that met the criteria were considered for the final manuscript. PRISMA guidelines were adopted for this study.
UNASSIGNED: Five main incision types have been described. In addition to the question mark incision, other common incisions include the T-Kempe, developed to obtain wide access to the skull, the retroauricular incision, designed to spare the occipital branch, as well as the N-shaped and cloverleaf incisions which integrate with pterional approaches. Advantages and drawbacks, integration with existing incisions, relationships with the main arteries, cosmetic outcomes, and risks of wound complications including dehiscence, necrosis, and infection were assessed.
UNASSIGNED: The reverse-question mark incision, despite being a mainstay of trauma neurosurgery, can place the vascular supply to the scalp at risk and favor wound dehiscence and infection. Several incisions, such as the T-Kempe, retroauricular, N-shaped, and cloverleaf approaches have been developed to preserve the main vessels supplying the scalp. Incision choice needs to be carefully weighted based on the patient\'s anatomy, position and size of main vessels, risk of wound dehiscence, and desired volume of decompression.

The \"Letter to the Editor\" titled \"Scalp incision technique for decompressive hemicraniectomy: comparative systematic review and meta-analysis of the reverse question mark versus alternative retroauricular and Kempe incision techniques of published cases\" provides a detailed analysis of different scalp incision techniques in decompressive hemicraniectomy procedures. While commendable for its systematic approach and valuable insights, the letter has several limitations, including a lack of transparency in the search strategy, failure to address potential sources of bias, and a narrow focus on technical aspects without considering broader outcome domains and practical considerations. Despite these limitations, the letter underscores the importance of evidence-based decision-making in neurosurgical practice and calls for further research to address these gaps.

This study presents a critical analysis of complications following cranioplasty (CP) after decompressive hemicraniectomy, focusing on autologous, polymethylmethacrylate (PMMA), and computer-aided design (CAD) implants. The analysis encompasses a retrospective bicenter assessment, evaluating factors influencing surgical outcomes and emphasizing the significance of material selection in minimizing postoperative complications. The study\'s comprehensive examination of complication rates associated with various implant materials contributes significantly to understanding CP outcomes. While polymethylmethacrylate (PMMA) and autologous bone flaps (ABFs) exhibited higher rates of surgical site infection (SSI) and explantation, a meta-analysis revealed a contrasting lower infection rate for polyether ether ketone (PEEK) implants. The study underscores the critical role of material selection in mitigating postoperative complications. Despite its strengths, the study\'s retrospective design, reliance on data from two centers, and limited sample size pose limitations. Future research should prioritize prospective, multicenter studies with standardized protocols to enhance diagnostic accuracy and treatment efficacy in CP procedures.

Decompressive hemicraniectomy (DHC) is a critical procedure used to alleviate elevated intracranial pressure (ICP) in emergent situations. It is typically performed to create space for the swelling brain and to prevent dangerous and potentially fatal increases in ICP. DHC is indicated for pathologies ranging from MCA stroke to traumatic subarachnoid hemorrhage-essentially any cause of refractory brain swelling and elevated ICPs. Scalp incisions for opening and closing the soft tissues during DHC are crucial to achieve optimal outcomes by promoting proper wound healing and minimizing surgical site infections (SSIs). Though the reverse question mark (RQM) scalp incision has gained significant traction within neurosurgical practice, alternatives-including the retroauricular (RA) and Kempe incisions-have been proposed. As choice of technique can impact postoperative outcomes and complications, we sought to compare outcomes associated with different scalp incision techniques used during DHC. We queried three databases according to PRISMA guidelines in order to identify studies comparing outcomes between the RQM versus \"alternative\" scalp incision techniques for DHC. Our primary outcome of interest in the present study was postoperative wound infection rates according to scalp incision type. Secondary outcomes included estimated blood loss (EBL) and operative duration. We identified seven studies eligible for inclusion in the formal meta-analysis. The traditional RQM technique shortened operative times by 36.56 min, on average. Additionally, mean EBL was significantly lower when the RQM scalp incision was used. Postoperatively, there was no significant association between DHC incision type and mean intensive care unit (ICU) length of stay (LOS), nor was there a significant difference in predisposition to developing wound complications or infections between the RQM and retroauricular/Kempe incision cohorts. Superficial temporal artery (STA) preservation and reoperation rates were collected but could not be analyzed due to insufficient number of studies reporting these outcomes. Our meta-analysis suggests that there is no significant difference between scalp incision techniques as they relate to surgical site infection and wound complications. At present, it appears that outcomes following DHC can be improved by ensuring that the bone flap is large enough to enable sufficient cerebral expansion and decompression of the temporal lobe, the latter of which is of particular importance. Although previous studies have suggested that there are several advantages to performing alternative scalp incision techniques during DHC, the present study (which is to our knowledge the first to meta-analyze the literature on outcomes in DHC by scalp incision type) does not support these findings. As such, further investigations in the form of prospective trials with high statistical power are merited.

This study explored short- and mid-term functional outcomes in patients undergoing decompressive hemicraniectomy (DHC) due to space-occupying cerebral infarction and asked whether there is a potentially harmful effect of a priorly performed endovascular treatment (EVT). Medical records were screened for patients requiring DHC due to space-occupying cerebral infarction between January 2016 and July 2021. Functional outcomes at hospital discharge and at 3 months were assessed by the modified Rankin Scale (mRS). Out of 65 patients with DHC, 39 underwent EVT before DHC. Both groups, i.e., EVT + DHC and DHC alone, had similar volumes (280 ± 90 mL vs. 269 ± 73 mL, t-test, p = 0.633) and proportions of edema and infarction (22.1 ± 6.5% vs. 22.1 ± 6.1%, t-test, p = 0.989) before the surgical intervention. Patients undergoing EVT + DHC tended to have a better functional outcome at hospital discharge compared to DHC alone (mRS 4.8 ± 0.8 vs. 5.2 ± 0.7, Mann-Whitney-U, p = 0.061), while the functional outcome after 3 months was similar (mRS 4.6 ± 1.1 vs. 4.8 ± 0.9, Mann-Whitney-U, p = 0.352). In patients initially presenting with a relevant infarct demarcation (Alberta Stroke Program Early CT Score ≤ 5), the outcome was similar at hospital discharge and after 3 months between patients with EVT + DHC and DHC alone. This study provided no evidence for a harmful effect of EVT before DHC in patients with space-occupying brain infarction.

Cranioplasty (CP) after decompressive hemicraniectomy (DHC) is a common neurosurgical procedure with a high complication rate. The best material for the repair of large cranial defects is unclear. The aim of this study was to evaluate different implant materials regarding surgery related complications after CP. Type of materials include the autologous bone flap (ABF), polymethylmethacrylate (PMMA), calcium phosphate reinforced with titanium mesh (CaP-Ti), polyetheretherketone (PEEK) and hydroxyapatite (HA). A retrospective, descriptive, observational bicenter study was performed, medical data of all patients who underwent CP after DHC between January 1st, 2016 and December 31st, 2022 were analyzed. Follow-up was until December 31st, 2023. 139 consecutive patients with a median age of 54 years who received either PMMA (56/139; 40.3%), PEEK (35/139; 25.2%), CaP-Ti (21/139; 15.1%), ABF (25/139; 18.0%) or HA (2/139; 1.4%) cranial implant after DHC were included in the study. Median time from DHC to CP was 117 days and median follow-up period was 43 months. Surgical site infection was the most frequent surgery-related complication (13.7%; 19/139). PEEK implants were mostly affected (28.6%; 10/35), followed by ABF (20%; 5/25), CaP-Ti implants (9.5%; 2/21) and PMMA implants (1.7%, 1/56). Explantation was necessary for 9 PEEK implants (25.7%; 9/35), 6 ABFs (24.0%; 6/25), 3 CaP-Ti implants (14.3%; 3/21) and 4 PMMA implants (7.1%; 4/56). Besides infection, a postoperative hematoma was the most common cause. Median surgical time was 106 min, neither longer surgical time nor use of anticoagulation were significantly related to higher infection rates (p = 0.547; p = 0.152 respectively). Ventriculoperitoneal shunt implantation prior to CP was noted in 33.8% (47/139) and not significantly associated with surgical related complications. Perioperative lumbar drainage, due to bulging brain, inserted in 38 patients (27.3%; 38/139) before surgery was protective when it comes to explantation of the implant (p = 0.035). Based on our results, CP is still related to a relatively high number of infections and further complications. Implant material seems to have a high effect on postoperative infections, since surgical time, anticoagulation therapy and hydrocephalus did not show a statistically significant effect on postoperative complications in this study. PEEK implants and ABFs seem to possess higher risk of postoperative infection. More biocompatible implants such as CaP-Ti might be beneficial. Further, prospective studies are necessary to answer this question.

BACKGROUND: Reimplantations of autologous skull flaps after decompressive hemicraniectomies (DHs) are associated with high rates of postoperative bone flap resorption (BFR). We histologically assessed the cell viability of explanted bone flaps in certain periods of time after DH, in order to conclude whether precursors of BRF may be developed during their storage.
METHODS: Skull bone flaps explanted during a DH between 2019 and 2020 were stored in a freezer at either -23 °C or -80 °C. After their thawing process, the skulls were collected. Parameters of bone metabolism, namely PTH1 and OPG, were analyzed via immunohistochemistry. H&E stain was used to assess the degree of avital bone tissue, whereas the repeated assays were performed after 6 months.
RESULTS: A total of 17 stored skull flaps (8 at -23 °C; 9 at -80 °C) were analyzed. The duration of cryopreservation varied between 2 and 17 months. A relevant degree of bone avitality was observed in all skull flaps, which significantly increased at the repeated evaluation after 6 months (p < 0.001). Preservation at -23 °C (p = 0.006) as well as longer storage times (p < 0.001) were identified as prognostic factors for higher rates of bone avitality in a linear mixed regression model.
CONCLUSIONS: Our novel finding shows a clear benefit from storage at -80° C, which should be carefully considered for the future management and storage of explanted skull flaps. Our analysis also further revealed a significant degree of bone avitality, a potential precursor of BFR, in skull flaps stored for several weeks. To this end, we should reconsider whether the reimplantation of autologous skull flaps instead of synthetic skull flaps is still justified.

Delayed traumatic intracerebral hematoma (DTICH) is a relatively common occurrence after a traumatic brain injury (TBI). Several case series have been performed to study DTICH, many of which offer different definitions of DTICH. Some definitions involve a delayed progression of an existing hemorrhage, and others involve a de novo intracerebral hematoma that was not evident on the initial trauma evaluation. We propose a classification system for DTICH that accounts for the subtleties in the clinical manifestation and pathophysiology of the different types of DTICH, with the ultimate goal of providing strategies to prevent and manage DTICH. Based on the senior author\'s clinical experience, we generated a classification system for DTICH, and each type of DTICH was illustrated with a case. We defined type 1A (case 1A), the classic presentation of DTICH as predominantly characterized in the literature, as an intracerebral hematoma unseen on initial computed tomography imaging that typically develops five days to one week following blunt or penetrating head trauma. We defined type 1B (case 1B) as a hematoma that forms after at least one week following trauma in areas of the brain initially hemorrhage-free. We defined type 2 (case 2) as a hematoma that develops rapidly following a surgical evacuation of a different hematoma. We defined type 3 (case 3) as a hematoma that develops after a traumatic head injury in areas of non-hemorrhagic contusion, usually frontal or temporal. A literature review was performed using select terms on PubMed to find articles related to DTICH, excluding articles describing DTICH from an underlying vascular injury. After performing the literature review and screening articles by title and/or abstract, a total of 79 articles were found to meet the inclusion and exclusion criteria. We recorded which type of DTICH from our classification system best correlated with the articles in our literature review. Taken together with results from the literature, the proposed classification system is based on the senior author\'s clinical experience. Overall, DTICH is a relatively common occurrence after head trauma, and our pathophysiologic classification has the potential to help outline future studies to recognize and prevent the development of DTICH.

BACKGROUND: Even though mechanical recanalization techniques have dramatically improved acute stroke care since the pivotal trials of decompressive hemicraniectomy for malignant courses of ischemic stroke, decompressive hemicraniectomy remains a mainstay of malignant stroke treatment. However, it is still unclear whether prior thrombectomy, which in most cases is associated with application of antiplatelets and/or anticoagulants, affects the surgical complication rate of decompressive hemicraniectomy and whether conclusions derived from prior trials of decompressive hemicraniectomy are still valid in times of modern stroke care.
METHODS: A total of 103 consecutive patients who received a decompressive hemicraniectomy for malignant middle cerebral artery infarction were evaluated in this retrospective cohort study. Surgical and functional outcomes of patients who had received mechanical recanalization before surgery (thrombectomy group, n = 49) and of patients who had not received mechanical recanalization (medical group, n = 54) were compared.
RESULTS: The baseline characteristics of the two groups did significantly differ regarding preoperative systemic thrombolysis (63.3% in the thrombectomy group vs. 18.5% in the medical group, p < 0.001), the rate of hemorrhagic transformation (44.9% vs. 24.1%, p = 0.04) and the preoperative Glasgow Coma Score (median of 7 in the thrombectomy group vs. 12 in the medical group, p = 0.04) were similar to those of prior randomized controlled trials of decompressive hemicraniectomy. There was no significant difference in the rates of surgical complications (10.2% in the thrombectomy group vs. 11.1% in the medical group), revision surgery within the first 30 days after surgery (4.1% vs. 5.6%, respectively), and functional outcome (median modified Rankin Score of 4 at 5 and 14 months in both groups) between the two groups.
CONCLUSIONS: A prior mechanical recanalization with possibly associated systemic thrombolysis does not affect the early surgical complication rate and the functional outcome after decompressive hemicraniectomy for malignant ischemic stroke. Patient characteristics have not changed significantly since the introduction of mechanical recanalization; therefore, the results from former large randomized controlled trials are still valid in the modern era of stroke care.