INTRODUCTION
Meningiomas arise from the meningothelial cell of the arachnoid layer and showcases one of the most prevalent primary brain cancers[1,2]. A large number of meningiomas are harmless and show gradual growth[3]; however, the clinical behavior can differ significantly depending upon factors like tumor size, location, pathological grade, and the patient’s overall health[1,3]. Surgical excision is the primary treatment for symptomatic, growing or aggressively invasive tumors[4]. The degree of resection is no longer the sole criterion for assessing the success of meningioma surgery[4,5]. Current neurosurgical care increasingly emphasizes postoperative recovery complication rates, functional status, recurrence and long-term quality of life. Combined disorders have gained significant importance in these situation as they may affect both perioperative progression and the ultimate prognosis.
Diabetes mellitus is a significant systemic disorder that affects surgical results. The recurrent metabolic disorder is classified as extended hyperglycemia and impairments in insulin secretion or function[6]. Diabetes affects cellular immunity, vascular function, inflammatory pathways, blood clotting, and tissue repair, along with disrupting affecting homeostasis[7,8]. The systemic implications are essential in surgery, when wound healing, infection resistance, and physiological stability are important for recovery. Diabetes has always been associated with elevated perioperative morbidity, extended hospital stays, increased infection rates, and delayed recovery in general surgical populations[9-11]. In neurosurgery, these effects may hold therapeutic importance because of the brain and its associated structures higher susceptibility of inflammation, edema, metabolic stress and vascular abnormalities.
Recent findings confirm that diabetes may be an important concern for patients undergoing meningioma surgeries. Retrospective cohort studies indicate that, relative to non-diabetic persons, patients with diabetes experience prolonged hospitalizations, increased incidence of surgical site infections, heightened postoperative cerebral edema, greater neurological sequelae, and decreased functional recovery[12,13]. In addition, several studies indicate that diabetes may be associated with increased long-term mortality and recurrence[12,14], emphasizing that metabolic deficiencies can influence both tumor-related prognosis and perioperative safety. These results have significance since they suggest that diabetes is not a latent condition that remains undetected. It can significantly influence the integrity of the blood-brain barrier, accelerate wound healing, control vascular permeability and modulate the inflammatory response during brain surgery.
The mechanism behind this connection is quite complex. Enhanced oxidative stress, decreased tissue oxygen level, poor cell functioning, delayed collagen deposition, and delayed epithelial repair are the effects of chronic hyperglycemia[7,15]. Also, diabetes is associated to endothelial cell damage and microvascular abnormalities, which can prevent post-operative tissue regeneration and increases the risk of infection[7]. These changes can impact the time required to return to neurological baseline, the recovery of the surgical site, and the treatment of edema in neurosurgery. Additionally, inflammatory response and metabolic disorder can increase the impact on tumor biology, possibly affecting long-term results and risk of recurrence[8]. Therefore, diabetes can impact on both, immediate surgical recovery and the long-term outcome of this condition.
The study has important clinical implications for perioperative management. Diabetic patients undergoing meningioma surgery may require comprehensive preoperative optimization including glycemic assessment, nutritional analysis and assessment of existing vascular disease[10,16]. Proper glucose control, improved infection surveillance, proactive edema control and multidisciplinary follow-up during and after surgery are essential[10,11]. When metabolic instability is not controlled, modern neurological techniques might not be appropriate for the high risk. As a result, risk assessment methodologies for surgical planning and postoperative advising should take diabetes into consideration.
This study highlights the information on the connection between diabetes and surgical outcomes for patients having meningioma. It provides the summary on biological and epidemiological context, also examines the existing clinical data, explores potential mechanisms connecting diabetes to adverse outcomes, and addresses implications for perioperative management and future investigations. Diabetes is an important factor that affects neurosurgical risk and personalized treatment plans which should be considered for patients having metabolic disorders.
EPIDEMIOLOGY AND CLINICAL CONTEXT
Meningioma contributes a significant percentage of cerebral malignant growth and are among the most common and primary brain tumors discovered in adults. It grows with age with many chronic conditions, including diabetes, obesity, hypertension, and cardiac disease[17-19]. The treatment of meningioma is especially essential for assessing preoperative risk, as surgical outcomes are dependent upon the patient’s overall condition and the tumor’s characteristics[20]. While most of the meningioma are pathologically harmless, their physical positioning can lead to significant neurological symptoms, including seizures, focal deficits, cognitive impairment, visual disturbances, or elevated intracranial pressure[18]. Therefore, surgery remains the primary mode of treatment in numerous circumstances[3].
The clinical progression of meningioma is affected by different factors which includes tumor size, location, grade, blood flow and the level of reaction[1,20]. Currently, postoperative recovery is equally important for the treatment’s efficiency[3]. Inappropriate treatment of underlying risk variable may result in a patient suffering from a technically flawless surgery yet still facing long-term hospitalization, infection, edema, or late neurological recovery[9,21]. It presents more commonly within the same age group as meningiomas, signifying a clinically relevant association between the two conditions[6,19]. The presence of diabetes and meningioma is significant, as diabetes can affect surgical tolerance and recovery, even when tumor is localized and susceptible to surgical intervention[12,21]. Hyperglycemia, compromised immunity, microvascular abnormalities, and delayed inflammatory response can affect wound healing and increase the risk of postoperative complications[14,15,22]. In the context of cerebral surgery, the susceptibility of brain tissue to edema, ischemia, and metabolic stress may exacerbate these effects[23]. Therefore, diabetic patients are required more strict and multidisciplinary management, a high level of glucose regulation, and extended postoperative monitoring compared to non-diabetic patients[9,10].
Diabetic patients undergoing meningioma surgery show a high infection rate, long-term hospital and intensive care unit stays, increased postoperative edema, and poor functional outcomes, as determined by recent clinical research[12,13,24]. Additionally, specific researches have suggested an association between diabetes and mortality or long-term recurrence, even though further investigation and research is required to validate this[25]. These research results indicate that diabetes should not be considered as a normal background condition but as a substantial clinical variable. This clinical and epidemiological context supports customized preoperative planning for diabetic meningioma patients. The classification of risks should be done before surgery and during the postoperative period[26]. When planning the procedure and calculating recovery, parameters such as glycemic control, hemoglobin A1c level, nutritional status, kidney function, and vascular disease must be taken into consideration[6,26]. Diabetes patients need further attention in the management of surgical tumor excision, as it may influence both immediate problems and long-term outcomes.
PATHOPHYSIOLOGY LINKING DIABETES AND SURGICAL RISK
Type 2 diabetes enhances surgical risk due to various interrelated biological factors that impact nearly all stages of healing. The main reason is continuous elevated glucose levels, which impairs the body’s capacity to adapt to surgical stress and affects normal cellular function[15,27]. High blood glucose levels limit neutrophil functionality, decrease chemotaxis and restrict cell phagocytosis, hence making the immune system less capable of preventing bacterial infection and early wound healing[14,27]. This clarifies the susceptibility of diabetes patients to slowed healing and surgical infections[8,27].
Blood vessel damage is another crucial factor. Diabetes affects small blood vessels by endothelial damage, basement membrane thickening, and reduced nitric oxide supply[15,28]. Healing takes time, oxygen supply is less efficient, and tissue blood supply decreases[28]. This increases the possibility of failure or infection and affects collagen synthesis and nutrient supply to the healing tissues in a surgical wound[14]. This is responsive to minor changes in circulation of oxygen. Insufficient vascular function in neurosurgery patients may result in a less stable recovery[23].
Additionally, diabetes causes a condition of chronic inflammation. In diabetes patients, inflammatory compounds such as cytokines and acute-phase reactants are often increased, leading to a continuous low-level stress response[16,29]. The unusual inflammation situation could intensify during surgery, leading to enhanced edema, prolonged tissue damage repair, and increased postoperative morbidity[29]. The increased inflammatory activity may pose particular risks during meningioma surgery, as cerebral edema is already an important concern[30]. Another significant factor is poor wound healing. Collagen formation, angiogenesis, and the synchronized migration of fibroblasts, cellular keratinocytes, and inflammatory cells are essential for proper healing and diabetes affects all of these processes[14,31]. Collagen synthesis is delayed, fibroblast activity is reduced, and angiogenesis is stopped[31]. This creates weak healing tissue that is more susceptible to infection and dehiscence. Even a small delay in the recovery of a brain surgical tumor can arise the necessity for postoperative monitoring and prolonged hospital stays[9].
Hyperglycemia affects the brain’s sensitivity to damage and may impede neurological recovery. High blood glucose levels may increase oxidative stress and cellular damage in vulnerable tissues[15,32]. In addition, they may affect the blood-brain barrier and affect capillary equilibrium, potentially resulting in edema[32]. Postoperative edema can impose pressure on surrounding brain regions in meningioma patients, affecting neurological recovery[30]. This indicates that blood sugar management is crucial for maintaining cerebral stability and supporting wound healing.
The relationship between blood coagulation and diabetes is of major importance. Diabetes is associated with vascular stiffness, platelet activation, and blood clotting condition[33]. This change can affect proper recovery and increase the risk of vascular problems in the perioperative situation. This increases the overall burden of surgical risk, although it does not affect the underlying process in meningioma operations. At some point, diabetes can affect tumor related outcomes through metabolic and inflammatory means. The impact of abnormal glucose metabolism on the tumor microenvironment, recurrence risk, and long-term prognosis is the subject of increasing interest[34]. The study highlights that diabetes should be seen as a significant disease, affecting both acute postoperative complications and long-term surgical outcomes. An overview of the integrated pathophysiological factors that bind diabetes to poor surgical outcomes are summarized in Figure 1.
Figure 1 Diabetes and meningioma surgical outcomes.
The figure highlights the unified physiopathological routes associated with the adverse outcomes of meningioma surgery in patients with diabetes. Persistently resulting in several physiological mechanisms, including immunological dysregulation, microvascular damage, chronic inflammation, impaired wound healing, and disruption of the blood-brain barrier. All of these mechanisms reduce the body’s capacity for adaptation to surgical stress, decrease blood flow, hinder wound healing, and increase risk to infection. Moreover, disability of the blood-brain barrier and inflammation cause cerebral edema and neurological impairment. These factors collectively result in suboptimal patient outcomes and heightened surgical complications. The contemporary concept perceives diabetes not merely as a static risk factor for neurosurgery, but as an active biological modulator of surgical risk.
EVIDENCE FROM CLINICAL STUDIES
Several clinical research studies focused on the correlation between diabetes and meningioma surgery, highlighting a general tendency of diabetes having connection to poor postoperative outcomes[12,13,24,35]. Previous studies have demonstrated that type 2 diabetes mellitus is an independent risk factor of postoperative issues in patients undergoing surgical treatment for tumor[12,35,36]. These findings highlight that metabolic disorders can impact outcome even when essential clinical factors are being corrected for. The research highlights a conclusion that diabetes patients are more prone to longer hospital stays[9,10,36]. This is particularly true in the case of meningioma surgery where patients often require close neurologic monitoring in the postoperative period. Diabetes can cause a longer and more complex hospital treatment due to an elevated risk of edema, seizures, or infection[23,30]. Diabetes represents a significant challenge for patient management and the proper allocation of medical resources.
A commonly mentioned issue is infection at the surgical site. Diabetes is known for affecting wound healing and immunological response, thus enhancing the risk of postoperative infections. A normal wound infection in meningioma patients may require supplementary treatments, extended antibiotic treatments, or a longer hospital stay. Some researchers have highlighted incidences of postoperative cerebral edema in diabetes patients[24,30]. Clinically, this is important because edema can aggravate neurological symptoms and may require prolonged monitoring or medical intervention. This indicates that diabetes can affect brain recovery post-surgery, and also impact wound healing. Studies highlight an increased number of neurological issues. Potential complications including focused impairments, prolonged awakening, seizures, or suboptimal functional recovery after surgery[12,13,36]. Considering that meningioma surgery occurs near eloquent brain regions, even a small increase in postoperative neurological instability may significantly impact the patient’s recovery and autonomy. During the primary postoperative phase, diabetes patients might require additional monitoring and supportive care.
Recent studies indicate that diabetes affects long term outcomes, including mortality and recurrence[25,37]. This finding appears more involved and potentially significant, highlighting that diabetes may ultimately influence tumor biology or the postoperative conditions. The results appear promising but should be evaluated carefully, as confounding criteria such as age, obesity, hypertension, hepatic illness, tumor size, and surgical complexity may influence retrospective studies. The consistency of available data strengthens the notion that diabetes is a significant indicator of outcomes rather than background conditions. Patients are likely to experience more educational challenges, a prolonged recovery, and potentially a poorer long-term prognosis compared to non-diabetic patients. This facilitates improved glucose control, enhanced postoperative monitoring, and more organized preoperative planning for this patient’s group[9,10,26].
MECHANISMS BEHIND POOR OUTCOMES
A variety of interrelated factors may lead to the adverse results in diabetes patients undergoing meningioma surgery. Additionally, diabetes affects the immune system. Meanwhile, diabetes impacts the immune system, vascular structures, wound healing, and brain function, making its consequences more acute following major surgical procedures such as brain surgery[27,28,31]. The body manages surgical stress, healing a brain injury, preventing infections, controlling edema and recovering neurological functions. Diabetes impacts each of these systems, emphasizing the higher risk of complications and the frequently prolonged recovery period. Essential possibilities are immunological dysfunction. In patients with diabetes, the functionality of neutrophils, macrophages, and other immune cells that typically help the body in reacting to surgical trauma and infections is reduced[14,27]. A little change at the surgical site is more prone to an infection due to inadequate immune response[8,27]. This is especially critical in neurosurgery, as surgical site infections can be difficult to control, leading to longer hospital stays, and requires further treatment. Diabetes affects the immune system and may extend inflammation resolution post-surgery, which affects tissue recovery[29].
A major secondary mechanism is vascular injury. Chronic hyperglycemia reduces tissue blood supply and oxygen delivery by affecting blood vessels and reducing endothelial cell function[28,38]. A sufficient amount of blood supply is essential for proper wound healing. Diabetic microangiopathy reduces the efficiency of this producer. This may result in prolonged healing of the infections and the tissues beneath the skull. This increases the risk of infection and delayed healing. Reduced microvascular circulation can affect the healing process and limit the flow of immune cells and tissue repair elements to the surgical site[28]. Diabetes is associated with persistent inflammation and oxidative damage. With increased glucose levels, there is an increase in the generation of reactive oxygen molecules, leading to cellular damage and the loss of normal repair processes[15,32,39]. Diabetes causes a persistent inflammatory condition, which may be increased post-operatively. Chronic inflammation may result in edema, tissue pain, and prolonged recovery duration. The significance of meningioma surgery lies in the possibility for neurological deficits and cerebral edema resulting from postoperative inflammation[30].
An additional significant factor affects wound healing. Effective healing requires cell activation, collagen production, angiogenesis, and re-epithelialization, respectively. These processes suffer in diabetes[14,31,40]. Diabetes reduces synthesis of collagen, affects fibroblast function, and blocked vasculature[40]. This can result in longer time for wound healing of the surgical incision and an increased risk of infection or wound recovery. Diabetes might have a negative impact on outcome as it affects the blood-brain barrier, which is critical for preserving a stable cerebral state after surgical procedures. High blood sugar level and inflammatory damage can increase vascular permeability and cause barrier instability[32,41]. This may result in extravasation of fluid into the surrounding tissue and aggravation of cerebral edema after surgery[30].
Diabetes can affect the stress response post-surgery. Surgery increases mediators of inflammation, cortisol levels, and catecholamines, respectively[42]. All of these components can further increase blood glucose levels. Stress-associated hyperglycemia may become progressively more difficult to manage in diabetes patients and can exacerbate their condition. Consequently, recovery is impeded by glycemic instability, and surgical intervention exacerbates this instability. The feedback mechanism could lead to the increased surgical complications and extended hospital stays frequently observed in diabetic patients[9,10]. The effect of diabetes on tumor biology and long term prognosis is a significant study domain. Metabolic imbalance, persistent inflammation, and abnormal insulin signaling may influence the tumor microenvironment[34,43]. A number of studies indicate a correlation between diabetes and mortality as well as recurrence following meningioma surgery; despite this, the evidence remains unclear[25,37]. This claim is disputed as it means that diabetes may influence both the progression of chronic diseases and the process of rapid healing.
Therefore, cellular immune suppressive responses, vascular injury, inflammation, oxidative stress, poor recovery processes, and blood-brain barrier failure are likely the principal factors leading to the poor clinical results in diabetic meningioma patients. Also, such mechanisms have a combined impact, creating a physiological state that is less favorable for postoperative recovery. Therefore, diabetes must be considered not only as a comorbid condition but as a significant modulator of neurosurgical risk.
PERIOPERATIVE MANAGEMENT AND CLINICAL IMPLICATIONS
After the initial postoperative phase, elevated blood glucose levels may cause the long-term prognosis of meningioma patients[25,44,45]. The inspection of meningioma treatment includes the day of surgery, recurrence risk, neurological recovery, survival rates, and long-term quality of life[46,47]. Diabetes is significant in neurosurgical treatment rather than being just a short-term preoperative risk factor, as it influences long-term results[48]. Earlier research has suggested that diabetes may be associated with higher mortality and recurrence rates after meningioma surgery[49-51]. This is concerning because diabetes can impair wound healing, contribute to edema, and affect the biological environment that may promote tumor recurrence[52]. However, these findings need to be confirmed further. Persistent high blood sugar levels, inflammation, and metabolic dysfunction can affect tumor activity, blood supply, and tissue repair, thereby increasing the risk of recurrence or complicating treatment[47,53,54].
The recovery process significantly affects the long-term outcome. Prolonged recovery may lead to tiredness, diminished autonomy, persistent weakness, seizures, and cognitive dysfunction post-surgery[53,55]. In diabetic patients, this issue may be increased by poorer healing, extended hospitalization, and a higher risk of surgical complications[36,56]. However, even if the surgery successfully removes the tumor, the overall advantages of the procedure may be compromised by a challenge in recovery. Therefore, functional outcome should be considered a significant element of prognosis. A further critical aspect is the necessity for prolonged monitoring. Patients with diabetes may require more regular inspections of metabolic stability and tumor recurrence[57]. Management of meningioma requires regular magnetic resonance imaging monitoring; however, in diabetic patients, follow-up should also cover neurological function, wound healing, nutritional status, and glycemic management[54,58]. “The patient appears stable after the surgery, but is at risk for complications later on if his diabetes isn’t well controlled”.
Diabetes can cause complications with other diseases, which can indirectly affect long-term outcomes. Patients with diabetes often experience weight gain, hypertension, cardiac disease, and renal failure, which might increase their mortality risk or recovery prognosis[19,46,55,59]. However, the existing research consistently proves patients with diabetes form a higher-risk cohort requiring more rigorous surveillance[51,56]. The long-term consequences of diabetes require careful consideration for the postoperative period. Follow-up management must include neurological assessment and imaging, with improved control of diabetes and lifestyle factors[45,57]. Improved long-term metabolic regulation may reduce overall morbidity, enhance healing, and reduce concerns regarding recurrence[57,58,60]. Therefore, diabetes must be considered not merely as a peri-operative concern, but also as an indication in long-term prognostic evaluation.
LIMITATIONS OF CURRENT EVIDENCE
Although significant evidence associating diabetes to adverse outcomes after meningioma surgery, various limitations reduce the reliability of these results[12,24,35,61]. The primary focus that a large number of studies are retroactive rather than prospective. Although retrospective researches are valuable for identifying patterns, they cannot clearly indicate that diabetes directly leads to adverse outcomes[61]. They can only state that diabetes is more frequently associated with poor outcomes than expected.
Another disadvantage is uncertainty. Patients with diabetes tend to be diagnosed with simultaneous chronic renal disease, obesity, hypertension, and cardiac disease[19,46,55,62]. The impact of diabetes can be challenging to differentiate from the total metabolic load, as these complications independently elevate surgical risk. Undetermined factors may continue to affect the outcome despite analytical correction[62]. This indicates that diabetes may act as an indicator of persons at higher risk rather than as a causal factor for negative consequences. The poor diagnosis of diabetes in many research studies is of a significant concern. Certain studies describe diabetes as either present or absent, omitting details like duration, severity, treatment type, hemoglobin A1c levels, insulin utilization, or extent of glycemic variability[45,63]. A patient with stable diabetes significantly differs from patients with uncontrolled diabetes, which highlights a substantial disadvantage. In its absence, it is challenging to identify which diabetes patients are at a higher risk or to determine whether sufficient glucose management could mitigate that risk. Recent studies suggest sample size as additional consideration. Past studies include small samples, whereas more recent studies are larger and more informative[35,64]. Smaller studies may adequately represent the range of surgical outcomes and result in misleading results. They might be further at risk of examining critical subgroups, such as various tumor locations, age demographics, or levels of glycemic control.
There are multiple existing theories on outcomes. Multiple research projects focus on hospital admission, whereas few examine infection, edema, neurological damage, or mortality[9,10,65]. Comparing research is challenging due to inconsistent measurement of outcomes. Unusual follow-up intervals may lead to incomplete long-term recurrence and survival data[54,66]. This is especially applicable to meningiomas where recurrence may occur years after post-surgery and cannot be assessed only based on initial outcomes. A limitation is the possible impact of variations in therapy for diabetic individuals and could require distinct perioperative care, including extended hospital stays, increased glucocorticoid treatment, or enhanced monitoring, which could independently affect outcomes[44,47,67]. Recovery varies across studies due to variations in surgical complexity, tumor size and location, blood loss, and surgeon expertise[20,53]. If these elements are not adequately considered, the impact of diabetes may be overstated.
Another drawback of research is the absence of molecular research. The exact molecular mechanisms remain poorly appreciated, as the majority of the existing data are clinical and observational[31,32,68]. Possible causes include disruption of the blood-brain barrier, inflammation, poor recovery, and blood vessel injury; however, the relationship of these factors to meningiomas remains poorly explored in study. Additional clinical studies are required to correlate a clinical observation with biological data.
Currently, there is insufficient information to confirm if optimizing control of glucose levels pre- or intra-operatively affects long-term outcomes, including mortality or recurrence[44,45,69]. This is a critical clinical question that remains unexplored. If more affective outcomes had been met through stricter glucose regulation, diabetes may be considered a controllable risk factor. Additionally, it may primarily reflect the fundamental vulnerability of the patient category. This subject remains unresolved until further thorough studies are published[69,70].
The data are informative and clinically beneficial. However, their application requires care. The correlation between diabetes and adverse results in meningioma surgery is proven, requiring rigorous prospective, multicenter trials to establish causality and effective management techniques[61,71,72].
CONCLUSION
Diabetes mellitus has been recognized as an important predictor of meningioma surgical outcomes. The consequences include glucose dysregulation, immune impairment, impaired wound healing, vascular injury, inflammation, and likely disruption of the blood-brain barrier. These changes explain the higher susceptibility for surgical infections, cerebral edema, neurologic complications, prolonged hospitalization, and delayed functional recovery in diabetic patients. Diabetes also may have effects on outcomes beyond the immediate perioperative period, as suggested by results presented by the study. Metabolic disorders may impact short-term recovery and long-term prognosis, as some studies demonstrate an association with mortality and recurrence rates. Overall, diabetes is a therapeutically relevant risk factor in neurosurgical oncology, although the available data are mostly retrospective and needs careful interpretation.
The findings support an individualized approach in the perioperative management. Careful preoperative evaluation, tight glycemic surveillance, infection monitoring, edema control, and multidisciplinary follow-up may minimize complications of meningioma resection in diabetic patients. Long-term follow-up should encompass metabolic optimization and tumor surveillance as recovery and quality of life may depend on adequate diabetes control.
In conclusion, diabetes should be considered an important modulator of surgical risk and outcomes rather than just a secondary disease. Understanding this relationship may improve risk assessment, guide perioperative management, and enhance postoperative care of meningioma patients.
Peer review: Externally peer reviewed.
Peer-review model: Single blind
Specialty type: Endocrinology and metabolism
Country of origin: India
Peer-review report’s classification
Scientific quality: Grade B, Grade B, Grade B
Novelty: Grade B, Grade B, Grade B
Creativity or innovation: Grade B, Grade B, Grade B
Scientific significance: Grade B, Grade B, Grade B
P-Reviewer: Batta A, MD, Associate Professor, India; Zhang JW, PhD, FRSC, Academic Fellow, Full Professor, Principal Investigator, China S-Editor: Bai Y L-Editor: Filipodia P-Editor: Zhang YL
