Persistent cauda equina syndrome after cesarean section under combined spinal-epidural anesthesia: a case report

Association between perioperative neuraxial local anesthetic neurotoxicity and arachnoiditis: a narrative review of published reports

BACKGROUND/IMPORTANCE

Arachnoiditis is a rare but devastating disorder caused by various insults, one of which is purported to be local anesthetic neurotoxicity following neuraxial blockade. However, the relationship between local anesthetics administered into the neuraxis and the development of arachnoiditis has not been clearly elucidated.

OBJECTIVE

We aimed to summarize the existing complex body of literature and characterize both the essential features and strength of any association between neuraxial local anesthetic neurotoxicity and arachnoiditis with a view toward mitigating risk, enhancing prevention, and refining informed consent discussions.

EVIDENCE REVIEW

We reviewed all published reports of arachnoiditis attributed to local anesthetic neurotoxicity following perioperative neuraxial anesthesia. This narrative review was based on a systematic search methodology, which included articles published up until December 2022.

FINDINGS

Thirty-eight articles were included, comprising 130 patients, over one-half of which were published prior to this century and inconsistent with modern practice. Neuraxial techniques included 78 epidurals, 48 spinals, and 5 combined spinal-epidurals, mostly for obstetrics. Reporting of essential procedural data was generally incomplete. Overall, at least 57% of patients experienced complicated needle/catheter insertion, including paresthesia, pain, or multiple attempts, irrespective of technique. The onset of neurological symptoms ranged from immediate to 8 years after neuraxial blockade, while the pathophysiology of arachnoiditis, if described, was heterogeneous.

CONCLUSIONS

The existing literature attributing arachnoiditis to local anesthetic neurotoxicity is largely outdated, incomplete, and/or confounded by other potential causes, and thus insufficient to characterize the features and strength of any association.

Resveratrol‑mediated activation of SIRT1 inhibits the PERK‑eIF2α‑ATF4 pathway and mitigates bupivacaine‑induced neurotoxicity in PC12 cells

Endoplasmic reticulum (ER) stress and apoptosis play significant roles in the development of neurotoxicity caused by bupivacaine (BUP). By activating sirtuin 1 (SIRT1), resveratrol (RSV) can regulate various cellular processes associated with anti-oxidative stress, anti-apoptosis and anti-inflammatory responses, thereby exerting neuroprotective effects. However, it remains unknown whether the activation of SIRT1 by RSV is able to attenuate BUP-induced ER stress and apoptosis. Therefore, the present study aimed to explore the effect of RSV on BUP-induced cytotoxicity in PC12 cells and the underlying mechanism. Cell Counting Kit-8 assays, flow cytometry and inverted phase-contrast microscopy were used to assess the viability, apoptosis rate and morphological changes of the cells, respectively. Western blotting and immunofluorescence staining were used to analyze the levels of SIRT1, the apoptosis-related proteins Bax, Bcl-2 and cleaved caspase-3, the ER stress-related proteins glucose-regulated protein 78, caspase-12 and CHOP, and the protein kinase RNA-like ER kinase (PERK)-eukaryotic translation initiation factor 2 α (eIF2α)-activating transcription factor 4 (ATF4) pathway-associated proteins phosphorylated (p)-PERK, PERK, p-eIF2α, eIF2α and ATF4. The results revealed that BUP induced cell apoptosis and decreased cell viability, accompanied by the downregulation of SIRT1. However, RSV restored SIRT1 protein expression, downregulated the expression of the pro-apoptotic protein Bax, upregulated the expression of the anti-apoptotic protein Bcl-2, decreased the apoptosis rate of the cells and increased cell viability. Furthermore, the anti-apoptotic effects exhibited by RSV were associated with inhibition of the PERK-eIF2α-ATF4 pathway of ER stress. However, the protective effect of RSV was significantly mitigated by the SIRT1 inhibitor EX527. These results indicate that the activation of SIRT1 by RSV alleviates BUP-induced PC12 cell ER stress and apoptosis via regulation of the PERK-eIF2α-ATF4 pathway. These findings offer insights into the molecular mechanism underlying BUP-induced apoptosis and suggest the potential of RSV as a therapeutic agent against the neurotoxicity caused by BUP.

Ferrostatin-1 ameliorates Bupivacaine-Induced spinal neurotoxicity in rats by inhibiting ferroptosis

Bupivacaine (BUP) has previously been shown to trigger neurotoxicity after spinal anesthesia. Further, ferroptosis has been implicated in the pathological processes associated with various central nervous system diseases. Although the impact of ferroptosis on BUP-induced neurotoxicity in the spinal cord has not been fully understood, this research aims to investigate this relationship in rats. Additionally, this study aims to determine whether ferrostatin-1 (Fer-1), a potent inhibitor of ferroptosis, can provide protection against BUP-induced spinal neurotoxicity. The experimental model for BUP-induced spinal neurotoxicity involved the administration of 5% bupivacaine through intrathecal injection. Then, the rats were randomized into the Control, BUP, BUP + Fer-1, and Fer-1 groups. BBB scores, %MPE of TFL, and H&E and Nissl stainings showed that intrathecal Fer-1 administration improved functional recovery, histological outcomes, and neural survival in BUP-treated rats. Moreover, Fer-1 has been found to alleviate the BUP-induced alterations related to ferroptosis, such as mitochondrial shrinkage and disruption of cristae, while also reducing the levels of malondialdehyde (MDA), iron, and 4-hydroxynonenal (4HNE). Fer-1 also inhibits the accumulation of reactive oxygen species (ROS) and restores the normal levels of glutathione peroxidase 4 (GPX4), cystine/glutamate transporter (xCT), and glutathione (GSH). Furthermore, double-immunofluorescence staining revealed that GPX4 is primarily localized in the neurons instead of microglia or astroglia in the spinal cord. In summary, we demonstrated that ferroptosis play a pivotal role in mediating BUP-induced spinal neurotoxicity, and Fer-1 ameliorated BUP-induced spinal neurotoxicity by reversing the underlying ferroptosis-related changes in rats.

Resveratrol Suppresses Bupivacaine-Induced Spinal Neurotoxicity in Rats by Inhibiting Endoplasmic Reticulum Stress via SIRT1 Modulation

Bupivacaine (BUP) may cause neurotoxic effects after spinal anesthesia. Resveratrol (RSV), a natural agonist of Silent information regulator 1 (SIRT1), protects various tissues and organs from damage by regulating endoplasmic reticulum (ER) stress. The aim of this study is to explore whether RSV could alleviate the neurotoxicity induced by bupivacaine via regulating ER stress. We established a model of bupivacaine-induced spinal neurotoxicity in rats using intrathecal injection of 5% bupivacaine. The protective effect of RSV was evaluated by injecting intrathecally with 30 μg/μL RSV in total of 10 μL per day for 4 consecutive days. On day 3 after bupivacaine administration, tail-flick latency (TFL) tests and the Basso, Beattie, and Bresnahan (BBB) locomotor scores were assessed to neurological function, and the lumbar enlargement of the spinal cord was obtained. H&E and Nissl staining were used to evaluate the histomorphological changes and the number of survival neurons. TUNEL staining was conducted to determine apoptotic cells. The expression of proteins was detected by IHC, immunofluorescence, and western blot. The mRNA level of SIRT1 was determined by RT-PCR. Bupivacaine caused spinal cord neurotoxicity by inducing cell apoptosis and triggering ER stress. RSV treatment promoted the recovery of neurological dysfunction after bupivacaine administration by suppressing neuronal apoptosis and ER stress. Furthermore, RSV upregulated SIRT1 expression and inhibited PERK signaling pathway activation. In summary, resveratrol suppresses bupivacaine-induced spinal neurotoxicity in rats by inhibiting endoplasmic reticulum stress via SIRT1 modulation.

The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis)

BACKGROUND & IMPORTANCE

This patient and public-involved systematic review originally focused on arachnoiditis, a supposedly rare "iatrogenic chronic meningitis" causing permanent neurologic damage and intractable pain. We sought to prove disease existence, causation, symptoms, and inform future directions. After 63 terms for the same pathology were found, the study was renamed Diseases of the Leptomeninges (DLMs). We present results that nullify traditional clinical thinking about DLMs, answer study questions, and create a unified path forward.

METHODS

The prospective PRISMA protocol is published at Arcsology.org. We used four platforms, 10 sources, extraction software, and critical review with ≥2 researchers at each phase. All human sources to 12/6/2020 were eligible for qualitative synthesis utilizing R. Weekly updates since cutoff strengthen conclusions.

RESULTS

Included were 887/14286 sources containing 12721 DLMs patients. Pathology involves the subarachnoid space (SAS) and pia. DLMs occurred in all countries as a contributor to the top 10 causes of disability-adjusted life years lost, with communicable diseases (CDs) predominating. In the USA, the ratio of CDs to iatrogenic causes is 2.4:1, contradicting arachnoiditis literature. Spinal fusion surgery comprised 54.7% of the iatrogenic category, with rhBMP-2 resulting in 2.4x more DLMs than no use (p<0.0001). Spinal injections and neuraxial anesthesia procedures cause 1.1%, and 0.2% permanent DLMs, respectively. Syringomyelia, hydrocephalus, and arachnoid cysts are complications caused by blocked CSF flow. CNS neuron death occurs due to insufficient arterial supply from compromised vasculature and nerves traversing the SAS. Contrast MRI is currently the diagnostic test of choice. Lack of radiologist recognition is problematic.

DISCUSSION & CONCLUSION

DLMs are common. The LM clinically functions as an organ with critical CNS-sustaining roles involving the SAS-pia structure, enclosed cells, lymphatics, and biologic pathways. Cases involve all specialties. Causes are numerous, symptoms predictable, and outcomes dependent on time to treatment and extent of residual SAS damage. An international disease classification and possible treatment trials are proposed.

Melatonin ameliorates bupivacaine-induced spinal neurotoxicity in rats by suppressing neuronal NLRP3 inflammasome activation

Bupivacaine is a common local anesthetic that causes neurotoxicity when used at clinical concentrations. Melatonin (MT), is a potent neuroprotective molecule. The study aimed to characterize the neuroprotective effects of MT on spinal neurotoxicity induced by bupivacaine in rats. It showed that bupivacaine, by intrathecal injection, induced spinal injury, and that the protein levels of Nod-like receptor protein 3 (NLRP3), cleaved caspase-1, and the N-terminal region of gasdermin D (GSDMD-N) were significantly increased. NLRP3 was expressed mainly in neurons and microglia. MT treatment ameliorated bupivacaine-induced spinal cord injury in rats by suppressing activation of neuronal NLRP3 inflammasomes.

The DNA Repair Enzyme XPD Is Partially Regulated by PI3K/AKT Signaling in the Context of Bupivacaine-Mediated Neuronal DNA Damage

Bupivacaine, a local anesthetic widely used for regional anesthesia and pain management, has been reported to induce neuronal injury, especially DNA damage. Neurons employ different pathways to repair DNA damage. However, the mechanism underlying bupivacaine-mediated DNA damage repair is unclear. A rat neuronal injury model was established by intrathecal injection of (3%) bupivacaine. An in vitro neuronal injury model was generated by exposing SH-SY5Y cells to bupivacaine (1.5 mmol/L). Then, a cDNA plate array was used to identify the DNA repair genes after bupivacaine exposure. The results showed that xeroderma pigmentosum complementary group D (XPD) of the nuclear excision repair (NER) pathway was closely associated with the repair of DNA damage induced by bupivacaine. Subsequently, Western blot assay and immunohistochemistry indicated that the expression of the repair enzyme XPD was upregulated after DNA damage. Downregulation of XPD expression by a lentivirus aggravated the DNA damage induced by bupivacaine. In addition, phosphatidyl-3-kinase (PI3K)/AKT signaling in neurons was inhibited after exposure to bupivacaine. After PI3K/AKT signaling was inhibited, bupivacaine-mediated DNA damage was further aggravated, and the expression of XPD was further upregulated. However, knockdown of XPD aggravated bupivacaine-mediated neuronal injury but did not affect PI3K/AKT signaling. In conclusion, the repair enzyme XPD, which was partially regulated by PI3K/AKT signaling, responded to bupivacaine-mediated neuronal DNA damage. These results can be used as a reference for the treatment of bupivacaine-induced neurotoxicity.

P53 inhibitor pifithrin-α inhibits ropivacaine-induced neuronal apoptosis via the mitochondrial apoptosis pathway

The neurotoxicity of local anesthetics (LAs) has attracted more and more attention, However, they lack preventive and therapeutic measures. Many studies have shown that apoptosis plays an important role in the process of LA-induced neurotoxicity. As an important signaling molecule to activate apoptosis, p53 has been proved to be involved in the neurotoxicity induced by LAs, but the mechanism is unclear. In this study, we explored the effect of pifithrin-α (PFT-α), a p53 inhibitor, on apoptosis by ropivacaine (Rop) in vivo and in vitro. Cell viability and apoptosis detected by CCK-8 and a JC-1 apoptosis detection kit, the changes of spinal cord structure observed after hematoxylin and eosin staining, apoptosis of the spinal cord measured by terminal deoxynucleotidyl transferase dUTP nick end labeling staining, behavioral assessment of the nerve Injury evaluated by the detection of sciatic nerve conduction velocity (SNCV) andmechanical withdrawal threshold (MWT), the expression of p53 and many apoptosis-related genes included Bax, Bcl-2, and caspase-3 detected by quantitative real-time polymerase chain reaction, Western blot analysis, immunofluorescence, and immunohistochemistry. Results showed that PC12 cell viability decreased because of Rop, but the pretreatment of PFT-α could protect it. And PFT-α reduced the injuries in the spinal cord by Rop included vacuoles or edema. The results of immunofluorescence and immunohistochemistry testing showed that PFT-α inhibited the p53 protein upregulated by Rop. Apoptosis rate and many proapoptotic genes include p53, Bax, caspase-3 messenger RNA, and proteins were increased by Rop, but PFT-α could decrease it. In conclusion, PFT-α inhibited cell apoptosis and spinal cord injuries induced by Rop.

Vocal fold paralysis and cauda equina syndrome following spinal-epidural anesthesia: A case report

RATIONALE

Vocal fold paralysis and cauda equina syndrome are very rare neurologic deficits. This report describes the case of a patient who simultaneously developed both after uneventful spinal-epidural anesthesia with 0.5% hyperbaric bupivacaine.

PATIENT CONCERNS

We report the case of a 45-year-old female, who underwent surgery for bilateral hallux valgus developed cauda equina syndrome and unilateral vocal fold paralysis after uneventful spinal-epidural anesthesia was administered. There was no pain or paresthesia during needle placement or drug injection. Surgery was performed uneventfully.

DIAGNOSES

Right vocal fold paralysis was diagnosed with flexible laryngoscopy.

INTERVENTIONS

Patient was started on the treatment with a surgery for bilateral hallux valgus, who developed cauda equina syndrome and unilateral vocal fold paralysis after uneventful spinal-epidural anesthesia was administered.

OUTCOMES

Postoperatively, she had difficulty in urination and defecation. In addition, she developed unilateral vocal fold paralysis characterized by hoarseness, effortful voice production, and choking with liquids. Magnetic resonance imaging performed on the lumbosacral area and computed tomography of the neck, the chest, and the skull revealed entirely normal results. However, flexible laryngoscopy revealed a right vocal fold paralysis. Although cauda equina syndrome can occur due to neurotoxicity of local anesthetics, the exact etiology of vocal fold paralysis is uncertain.

LESSONS

The case highlights that 2 rare and serious complications of spinal-epidural anesthesia can even occur in the same patient after uneventful surgery and block performance.

Impact of Anesthesia on Hospital Mortality and Morbidities in Geriatric Patients Following Emergency Hip Fracture Surgery

OBJECTIVES

To determine the impact of anesthesia type on in-hospital mortality and morbidity for geriatric fragility hip fracture surgery.

DESIGN

Retrospective cohort study.

SETTING

Integrates health care delivery system across 38 facilities in the United States.

PATIENTS/PARTICIPANTS

We identified 16,695 patients 65 years of age and older who underwent emergent hip fracture repairs between 2009 and 2014 through the Kaiser Permanente hip fracture registry and excluded pathologic or bilateral fractures.

INTERVENTION

Hip fracture surgery with general or regional anesthesia.

MAIN OUTCOMES MEASURES

Data on in-hospital mortality, time to death, discharge disposition, and length of stay (LOS) were analyzed among the following anesthesia types: general anesthesia (GA), regional anesthesia (RA), and intraoperative conversions from regional to general (Cv).

RESULTS

Compared with RA, the hazard ratio for GA for in-hospital mortality was 1.38 and 2.23 for the Cv group; the time ratio for GA-associated time to death was 0.97 and 0.89 for the Cv group. The GA-associated time ratio for LOS before discharge was 1.01, and the hazard ratio for home discharge was 0.86, but no significance was found with the Cv group.

CONCLUSIONS

RA may offer advantages over GA for fragility hip fracture surgeries when possible. In-hospital mortality, time to death, increased LOS, and discharge to an institute rather than home were all adversely influenced by GA. Furthermore, the previously understudied Cv group demonstrated adverse outcomes for in-hospital mortality and time to death.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.