ABSTRACT
Surgical resection is essential for treating solid tumors, with success largely dependent on the complete excision of neoplastic cells. However, neurosurgical procedures must delicately balance tumor removal with the preservation of surrounding tissue. Achieving clear margins is particularly challenging in cases like glioblastoma due to the limitations of traditional white light visualization. These limitations often result in incomplete resections, leading to frequent recurrences, or excessive resection that harms vital neural structures, causing iatrogenic nerve damage which can lead to sensory and functional deficits. Current statistics reveal a 90% recurrence rate for malignant gliomas. Similarly, an 8% incidence of iatrogenic nerve trauma contributes to an estimated 25 million cases of peripheral nerve injury globally each year. These figures underscore the urgent need for improved intraoperative techniques for lesion margin and nerve identification and visualization. Recent advances in neurosurgical imaging, such as fluorescence-guided surgery (FGS), have begun to address these challenges. Fluorescent agents used in FGS illuminate target tissues, although not all do so selectively. Despite the promising results of agents such as 5-aminolevulinic acid and indocyanine green, their applications are mainly limited by issues of sensitivity and specificity. Furthermore, these agents do not effectively address the need for precise nerve visualization. Nerve Peptide 41, a novel systemically administered fluorescent nerve-targeted probe, shows promise in filling this gap. This review assesses the major fluorescent imaging modalities in neurosurgery, highlighting each of their benefits, limitations, and potential.
ABSTRACT
Objective:To investigate the alterations of cholinergic and monoamine neurotransmitters in cerebrospinal fluid in patients with postoperative delirium.Methods:Sixty-eight patients with normal preoperative cognitive functions were enrolled.They were diagnosed with spinal extramedullary intradural space-occupying lesion and underwent surgical resection.Among these patients, 18 developed postoperative delirium (delirium group), 46 had no postoperative delirium (control group), and the diagnosis of delirium was unclear in four cases (excluded). Cerebrospinal fluid (CSF) was collected before the surgical resection of lesions and on the third day postoperatively.The concentrations of acetylcholine (Ach), norepinephrine (NE), adrenaline (E), dopamine (DA) and serotonin (5-HT) were measured using the high-performance liquid chromatography/electrochemical method.Results:Prior to the surgical resection, there were no significant differences in the Ach, NE, E, DA or 5-HT baseline levels in the CSF between the delirium group and the control group (all P>0.05). After surgery, the Ach level in the delirium group ((0.63±0.26) μmol/L) was significantly lower than that in the control group ((0.77±0.19) μmol/L) ( P=0.032), and there were no significant differences in other neurotransmitter levels (all P>0.05). In the delirium group, the level of Ach in the CSF after surgery ((0.63±0.26) μmol/L) was significantly lower than the baseline level ((0.75±0.19) μmol/L) ( P=0.021). The postoperative NE level ((1.58±0.28) μmol/L) was significantly higher than the baseline level ((1.49±0.21) μmol/L) ( P=0.036). There was no significant difference in the adrenaline level ( P=0.497). The postoperative DA level ((0.86±0.18) μmol/L) was significantly higher than the baseline level ((0.82±0.15) μmol/L) ( P=0.045), and the postoperative 5-HT level ((2.94±0.28) μmol/L) was also significantly higher than the baseline level ((2.75±0.35) μmol/L) ( P=0.022). In the control group, only the postoperative 5-HT level ((2.90±0.31) μmol/L) was significantly higher than the baseline level ((2.76±0.26) μmol/L) ( P=0.016), while the postoperative levels of other neurotransmitters were not significantly changed when compared to the baseline levels (all P>0.05). Conclusion:The cholinergic neurotransmitter levels were reduced while the monoamine neurotransmitter levels were increased in the cerebrospinal fluid in patients with postoperative delirium, which suggests that cholinergic hypoactivity and monoaminergic hyperexcitability may be important pathophysiological processes in the occurrence and development of postoperative delirium.
