Anatomy and Pathophysiology of Spinal Cord Injury Associated With Regional Anesthesia and Pain Medicine

Human dissection for anesthesiology resident training augments anatomical knowledge and clinical skills

Anatomy is an essential component of clinical anesthesiology. The use of simulated patients and alternative materials, including embalmed human bodies, have become increasingly common during resident physician training due to the deemphasis on anatomical education during undergraduate medical training. In this report, the need for a more extensive review of relevant anatomy for the practice of anesthesiology was addressed by the design, evaluation, and dissemination of a human dissection course for procedural training of anesthesiology residents. The course utilized "freedom art" embalmed human bodies that allowed trainees to perform ultrasound-based regional and neuraxial techniques followed by detailed dissections of critical anatomy. One hundred and four residents participated in workshops and small group discussions and were evaluated using pre- and post-course assessments. A variety of clinical techniques were performed on the bodies, including regional blocks and neuraxial catheter placement. Insertion of peripheral/neuraxial catheters was successful, with dissections demonstrating the expected placement. Assessment scores improved following the course (pre-course mean 52.7%, standard deviation (σ) 13.1%; post-course mean 72.2%, σ 11.6%; t-test p < 0.0001) and feedback highlighted the usefulness and clinical relevance of course content. The ability to correlate ultrasound imaging with subsequent dissections of the "blocked" area and visualization of dye staining was extremely relevant for spatial understanding of the anatomy relevant for the clinical practice of these techniques. This manuscript demonstrates successful implementation of a comprehensive course for anesthesiology resident physicians to address gaps in undergraduate anatomical education and suggests that broader adoption of dissection courses may be beneficial for training anesthesiologists.

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.

Tarlov cyst with self-healing cauda equina syndrome following combined spinal-epidural anesthesia: a case report

BACKGROUND

Cauda Equina Syndrome (CES) after Combined Spinal-Epidural Anesthesia (CSEA) is a rare disease that most of the time need surgery to relieve spinal cord compression.

CASE PRESENTATION

A 34-year-old male patient underwent a procedure for prolapse and hemorrhoids (PPH) under CSEA. Anesthesia and surgery were uneventful. However, the patient gradually experienced urinary retention, lower abdomen and back pain, changes in bowel habits and neurological dysfunction of the lower limbs when the catheter was removed. It was later determined that the patient had Tarlov cyst at the left S1 level in the sacral canal. Finally, the patient completely recovered 20 days after drug conservative therapy onset.

CONCLUSION

This case suggests that CES might occur even after ordinary CSEA. The risk factors are drug neurotoxicity to ropivacaine and Tarlov cyst, which helped to accumulate ropivacaine. The development of ultrasound-guided CSEA and an ultrasound atlas of the spinal canal are required.

Spinal anesthesia for L5-S1 interlaminar endoscopic lumbar discectomy: a retrospective study

OBJECTIVE

This study aimed to report our experience with spinal anesthesia (SA) in patients undergoing L5-S1 interlaminar endoscopic lumbar discectomy (IELD) and clarify its advantages and disadvantages.

METHODS

One hundred twelve patients who underwent IELD for an L5-S1 disc herniation under SA were retrospectively analyzed. SA with 0.5% ropivacaine was administered using a 27-gauge fine needle. Intraoperatively, the volume and level of SA, surgical time, blood loss, and cardiopulmonary complications were documented. Postoperative data was collected included the number of patients who ambulated on the day of surgery, incidence of complications and were then statistically analyzed.

RESULTS

Analgesia was complete throughout the entire operation in all patients and no other adjuvant intraoperative analgesic drugs were needed. Mean visual analog scale scores for intraoperative and early postoperative (24 h) pain were 0 and 2.43 ± 1.66. SA was administered at the L3-4 interspace in 34 patients (30.4%) and the L2-3 interspace in 78 (69.6%). Administration was successful with the first attempt in all patients. Mean operation time was 70.12 ± 6.52 min. Mean intraoperative blood loss volume was 20.71 ± 5.26 ml. Ninety-eight patients ambulated on the same day as surgery. Mean length of hospital stay was 24.36 ± 3.64 h. Dural injury without damaging the nerve root occurred in one patient. One patient experienced recurrent disc herniation. Intraoperative hypotension and respiratory distress occurred in five (4.5%) and three (2.7%) patients, respectively. Three patients (2.7%) received postoperative analgesia therapy and two (1.8%) experienced nausea. Two patients (1.8%) developed urinary retention. Spinal headache, cauda equina syndrome, and neurotoxicity did not occur.

CONCLUSION

SA can achieve satisfactory pain control for patients undergoing IELD with a low incidence of adverse events. SA may be a useful alternative to local and general anesthesia for IELD surgery. Future randomized controlled trials are warranted to investigate.

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.

Feasibility of continuous epidural analgesia in patients with failed back surgery syndrome and spinal stenosis

PURPOSE

The purpose of this study was to outline the feasibility of continuous epidural analgesia in the treatment of failed back surgery syndrome (FBSS) or spinal stenosis.

METHODS

We queried our prospective collected institutional database to include all consecutive patients, who underwent continuous epidural analgesia with accompanying intensive physiotherapeutic exercise within a timeframe of 4 years. Patients suffered from FBSS or spinal stenosis; protocolled continuous epidural analgesia was planned for 4 days within the framework of an inpatient multimodal pain therapy concept. The instillation technique of the epidural catheter, the capability to attend in accompanying physiotherapy, and the peri-interventional complications were evaluated.

RESULTS

153 patients with an average age of 57.4 years (± 11.9) were enrolled in this study. 105 patients suffered from FBSS and 48 patients had spinal stenosis. Overall, 148 patients (96.7%) reported the pain reduction and were able to perform daily intensified physiotherapeutic exercise. There were no serious adverse events, neither infection nor bleeding, no cardiopulmonary complication or permanent neurological deficits. The most common side effect was neurological impairment, such as numbness, dysesthesia, or weakness of the lower limbs with complete regression after flow rate adjustment. Patients with FBSS were more likely to develop dysesthesia (p = 0.007).

CONCLUSIONS

Continuous epidural analgesia is feasible in patients with FBSS or spinal stenosis. This treatment enables extensive physiotherapeutic treatment even in patients with severe pain conditions and can be considered as an alternative to epidural injections. An increased complication rate in comparison to short-term perioperative or perinatal application was not observed.

[Arachnoiditis following spinal anesthesia-Case report and review of the literature]

A 61-year-old woman underwent a tension-free vaginal tape (TVT) operation due to stress incontinence. After technically difficult spinal anesthesia with two attempts the patient developed symptoms of nerve irritation, complained about neckache and headache and showed signs of agitation. The regimen was shifted to general anesthesia and surgery was performed. Because of postoperatively persistent headache and sensory disturbances an MRI scan of the lumbar spine was performed on the first postoperative day without pathological findings. The patient was able to leave the hospital after 1 week with significant relief of symptoms but 3 weeks later she developed neurocognitive impairment with memory deficits. A second MRI scan of the head now showed signs of disturbance of CSF circulation with hydrocephalus. Treatment was performed with drainage and ventriculoperitoneal shunt. Further evaluation showed a severe, multisegmental arachnoiditis and the patient developed a progressive paraparesis. The patient presented her case for assessment to a commission on medical malpractice 13 months after anesthesia. The commission detected no treatment errors. In connection to the case report a literature review of characteristics and etiologies of chronic adhesive arachnoiditis is given, which is a known but very rare complication of spinal anesthesia or similar procedures.

Acute spinal cord injury: Pathophysiology and pharmacological intervention (Review)

Spinal cord injury (SCI) is one of the most debilitating of all the traumatic conditions that afflict individuals. For a number of years, extensive studies have been conducted to clarify the molecular mechanisms of SCI. Experimental and clinical studies have indicated that two phases, primary damage and secondary damage, are involved in SCI. The initial mechanical damage is caused by local impairment of the spinal cord. In addition, the fundamental mechanisms are associated with hyperflexion, hyperextension, axial loading and rotation. By contrast, secondary injury mechanisms are led by systemic and cellular factors, which may also be initiated by the primary injury. Although significant advances in supportive care have improved clinical outcomes in recent years, a number of studies continue to explore specific pharmacological therapies to minimize SCI. The present review summarized some important pathophysiologic mechanisms that are involved in SCI and focused on several pharmacological and non‑pharmacological therapies, which have either been previously investigated or have a potential in the management of this debilitating injury in the near future.

Spinal anesthesia in a patient on monoclonal antibody treatment: a poisoned chalice? A case report

BACKGROUND

Paraplegia is a rare complication of spinal anesthesia.

CASE PRESENTATION

We report a case of a 68-year-old man who developed postoperative paraplegia and hypoesthesia after spinal anesthesia for an otherwise uncomplicated transurethral resection of the prostate. Acute transverse myelitis was diagnosed based on urgent MRI. A prior history of similar though less severe neurological symptoms after obinutuzumab treatment for follicular lymphoma suggested a potential causative role for obinutuzumab, a novel monoclonal antibody that has not been associated with such devastating neurological side effects yet. High-dose steroid treatment partially attenuated the symptoms, but debilitating hypoesthesia and motor deficit remained present 3 months postoperatively.

CONCLUSION

The presented case warrants caution when performing neuraxial anesthesia in patients on monoclonal antibody therapies.

Hesperidin alleviates bupivacaine anesthesia-induced neurotoxicity in SH-SY5Y cells by regulating apoptosis and oxidative damage

Local anesthetic with bupivacaine (BV) administration may cause severe neurotoxicity and neurological complications in developing neurons. Any substances that can mitigate the toxic effects of BV are of great importance in surgical procedures and pain management. The present study attempted to investigate if hesperidin (HN) could inhibit or prevent BV-induced neurotoxicity in SH-SY5Y cells. Exposure of BV at 5 mM resulted in a significant decrease of cell viability and a remarkable increase of lactate dehydrogenase release via the induction of apoptosis and production of reactive oxygen species. Moreover, a loss of mitochondrial membrane potential, decreased Bcl-2 protein expression, as well as increased expression of cytoplasmic cytochrome c, Bax, and cleaved caspase-3 protein was also observed in BV-stimulated SH-SY5Y cells. In addition, BV stimulation impaired the balance of oxidation-reduction and inflammation system, as evidenced by the increased malondialdehyde content, decreased superoxide dismutase and catalase activity, and reduced level of reduced glutathione, interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α. However, these iatrogenic changes were all reversed by the HN (5, 10, and 20 μM) supplement for 48 h in a concentration-dependent manner. In conclusion, HN can protect SH-SY5Y cells against BV-stimulated neurotoxicity via the inhibition of apoptosis, oxidative stress, and inflammation response. The present findings suggested that HN may be an effective alternative agent to inhibit or prevent BV-induced neurotoxicity in human patients.

Beware the Wandering Needle: Inadvertent Intramedullary Injection During an Attempted Cervical Medial Branch Block

A 27-year-old man developed sudden neck pain, severe quadriparesis, and right shoulder allodynia during an outpatient cervical medial branch block procedure. Cervical spine imaging revealed evidence of an interlaminar needle trajectory with abnormal signal in the right hemicord at the level of C4, consistent with intramedullary injection and contusion. Following a 48-hour stay in the intensive care unit, during which hemodynamic vasopressor support was administered to optimize spinal cord perfusion, the patient exhibited almost complete neurologic recovery with resolution of the neuropathic pain. He was eventually discharged home and underwent outpatient physical therapy for a mild residual right hemiparesis.

Fluoroscopically guided lumbar spine interlaminar and transforaminal epidural injections: inadvertent intravascular injection

BACKGROUND

Inadvertent intravascular injection is a rare but catastrophic complication of lumbar epidural injections.

PURPOSE

To determine risk factors for inadvertent intravascular injection in fluoroscopically guided lumbar spine epidural injections.

MATERIAL AND METHODS

A total of 212 patients who presented for lumbar interlaminar or transforaminal injection were prospectively enrolled. Patient demographics, history of surgery, injection side, site and approach, and volume of contrast injected were recorded.

RESULTS

There were 89 (42%) interlaminar and 123 (58%) transforaminal injections. For 36 (17%) patients, there had been surgery at the injected or adjacent lumbar level. There were 25 (12%) inadvertent intravascular injections, with an incidence of 2/93 (2%) for interlaminar and 23/119 (19%) for transforaminal injections. The patients with inadvertent intravascular injection were older (P = 0.017) and had prior surgery at or adjacent to the level of injection (P < 0.0001). Transforaminal approach had a higher intravasation rate than interlaminar injections, both when comparing the entire cohort (P = 0.0001) and only patients without prior surgery (P = 0.01). In multivariable logistic regression analysis, transforaminal injections (odds ratio [OR] 9.77, 95% confidence interval [CI] 2.14-44.6, P = 0.003) and prior surgery at or adjacent to the level of injection (OR 5.71, 95% CI 2.15-15.15, P < 0.001) were independently associated with increased risk of inadvertent intravascular injections.

CONCLUSION

Inadvertent intravascular injection occurred in 12% of our lumbar injection cohort and is more common with transforaminal injections, in older patients, and with prior lumbar surgery at or adjacent to the level of injection.

Monosialoganglioside protects against bupivacaine-induced neurotoxicity caused by endoplasmic reticulum stress in rats

Background

Local anesthetics in spinal anesthesia have neurotoxic effects, resulting in severe neurological complications. Intrathecal monosialoganglioside (GM1) administration has a therapeutic effect on bupivacaine-induced neurotoxicity. The aim of this study was to determine the underlying mechanisms of bupivacaine-induced neurotoxicity and the potential neuroprotective role of GM1.

Materials and methods

A rat spinal cord neurotoxicity model was established by injecting bupivacaine (5%, 0.12 μL/g) intrathecally. The protective effect of GM1 (30 mg/kg) was evaluated by pretreating the animals with it prior to the bupivacaine regimen. The neurological and locomotor functions were assessed using standard tests. The histomorphological changes, neuron degeneration and apoptosis, and endoplasmic reticulum stress (ERS) relevant markers were analyzed using immunofluorescence, quantitative real-time PCR, and Western blotting.

Results

Bupivacaine resulted in significant neurotoxicity in the form of aberrant neurolocomoter functions and spinal cord histomorphology and neuronal apoptosis. Furthermore, the ERS specific markers were significantly upregulated during bupivacaine-induced neurotoxicity. These neurotoxic effects were ameliorated by GM1.

Conclusion

Pretreatment with GM1 protects against bupivacaine-induced neurotoxicity via the inhibition of the GRP78/PERK/eIF2α/ATF4-mediated ERS.

Trends in practice and safety measures of epidural analgesia: Report of a national survey

BACKGROUND

The clinical use of epidural analgesia has changed over past decades. Minimally invasive surgery and emergence of alternative analgesic techniques have led to an overall decline in its use. In addition, there is increasing awareness of the patient-specific risks for complications such as spinal haematoma and abscess. Local guidelines for management of severe neurological complications during or after epidural analgesia, ie, "epidural alert systems", have been introduced in hospitals to coordinate and potentially streamline early diagnosis and treatment. How widely such protocols have been implemented in daily practice is unknown.

METHODS

We conducted a survey to analyse trends in practice, key indications, safety measures, safety reporting, and management of complications of epidural analgesia in the Netherlands. Data were gathered using a web-based questionnaire and analysed using descriptive statistics.

RESULTS

Questionnaires from 85 of all 94 Dutch hospitals performing epidural analgesia were collected and analysed, a 90% response rate. Fifty-five percent reported a trend towards decreased use of perioperative epidural analgesia, while 68% reported increasing use of epidural analgesia for labour. Reported key indications for epidural analgesia were thoracotomy, upper abdominal laparotomy, and abdominal cancer debulking. An epidural alert system for neurological complications of epidural analgesia was available in 45% of hospitals.

CONCLUSIONS

This national audit concerning use and safety of epidural analgesia demonstrates that a minority of Dutch hospitals have procedures to manage suspected neurological complications of epidural analgesia, whereas in the remaining hospitals responsibilities and timelines for management of epidural emergencies are determined on an ad hoc basis.

TNF-alpha and TNF-R1 regulate bupivacaine-induced apoptosis in spinal cord dorsal root ganglion neuron

Local anesthesia has been shown to render severe spinal cord neurotoxicity. This study used an in vitro model to explore the expression and function of tumor necrosis factor (TNF) signaling pathway in bupivacaine-induced apoptotic injury in spinal cord dorsal root ganglia (DRG). DRG was prepared from adult C57BL/6 mice and incubated with 10 mM bupivacaine in vitro to induce apoptosis. QRT-PCR and western blot demonstrated that bupivacaine upregulated TNF-alpha (TNF-α) and TNF receptor 1 (TNF-R1), but left TNF receptor 2 (TNF-R2) unaffected in DRG. SiRNA-mediated TNF-α or TNF-R1 inhibition, but not TNF-R2 inhibition, rescued bupivacaine-induced DRG apoptosis. In addition, qRT-PCR and western blot demonstrated that downstream substrates of apoptotic and TNF signaling pathways, caspase-9, MAP3K and JNK, were all significantly downregulated by TNF-α or TNF-R1 inhibition, but not by TNF-R2 inhibition, in bupivacaine-injured DRG. Thus, our work suggested that TNF-α and TNF-R1 are the major contributors of TNF signaling pathway in anesthesia-induced spinal cord neurotoxicity. Targeting TNF-α / TNF-R1, not TNF-R2 signaling pathway may be the key component to rescue or prevent anesthesia-induced apoptotic injury in spinal cord neurons.

[Intramedullary injection with tethered cord : Case report of a rare complication during spinal anesthesia]

Although very rare, severe neurological complications can occur when undergoing spinal anesthesia. This report describes and analyses a case of spinal injury due to an undiagnosed tethered cord (TC) during spinal anesthesia for a cesarean section of a 31-year-old woman expecting twins. As a consequence of spinal dysraphism during embryogenesis, an atypically low conus level can occur and increase the risk of injury during neuraxial anesthesia, especially in the absence of symptoms. Injuries can be caused by mechanical trauma from direct needle injury, hematoma or neurotoxicity from local anesthetics. Special attention should therefore be paid to frequent symptoms, such as a hairy nevus on the back, deformities of the feet or bladder and bowels, voiding and micturition dysfunction in order to reduce the risk of complications.

Anterior chamber associated immune deviation used as a neuroprotective strategy in rats with spinal cord injury

The inflammatory response is probably one of the main destructive events occurring after spinal cord injury (SCI). Its progression depends mostly on the autoimmune response developed against neural constituents. Therefore, modulation or inhibition of this self-reactive reaction could help to reduce tissue destruction. Anterior chamber associated immune deviation (ACAID) is a phenomenon that induces immune-tolerance to antigens injected into the eye´s anterior chamber, provoking the reduction of such immune response. In the light of this notion, induction of ACAID to neural constituents could be used as a potential prophylactic therapy to promote neuroprotection. In order to evaluate this approach, three experiments were performed. In the first one, the capability to induce ACAID of the spinal cord extract (SCE) and the myelin basic protein (MBP) was evaluated. Using the delayed type hypersensibility assay (DTH) we demonstrated that both, SCE and MBP were capable of inducing ACAID. In the second experiment we evaluated the effect of SCE-induced ACAID on neurological and morphological recovery after SCI. In the results, there was a significant improvement of motor recovery, nociceptive hypersensitivity and motoneuron survival in rats with SCE-induced ACAID. Moreover, ACAID also up-regulated the expression of genes encoding for anti-inflammatory cytokines and FoxP3 but down-regulated those for pro-inflamatory cytokines. Finally, in the third experiment, the effect of a more simple and practical strategy was evaluated: MBP-induced ACAID, we also found significant neurological and morphological outcomes. In the present study we demonstrate that the induction of ACAID against neural antigens in rats, promotes neuroprotection after SCI.

Bleeding and Neurologic Complications in 58,000 Interventional Pain Procedures

BACKGROUND AND OBJECTIVES

Interventional pain procedures are commonly performed on patients receiving antiplatelet therapy. However, there is limited evidence to support or refute the safety of this practice. The goal of this investigation was to assess the rate of bleeding complications in a large cohort of patients undergoing intermediate- and low-risk pain procedures, with a specific focus on antiplatelet and anticoagulant medication use and baseline coagulation abnormalities.

METHODS

This is a retrospective cohort study of adult patients undergoing low- and intermediate-risk pain procedures from 2005 through 2014 by the division of pain medicine at a single academic tertiary care center. Baseline characteristics, antiplatelet and anticoagulant medication use, coagulation parameters, and procedural details were extracted from the electronic medical record. The primary outcome was a bleeding-related complication requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days. The secondary outcome was the presence or absence of a periprocedural red blood cell transfusion occurring within 72 hours of needle placement.

RESULTS

A total of 58,066 procedures were performed on 24,590 unique patients. Preprocedural aspirin or nonsteroidal anti-inflammatory drug therapy was present for 17,825 procedures (30.7%). Sixteen procedures were associated with perioperative red blood cell transfusion (0.03%), with no difference based on preprocedural nonsteroidal anti-inflammatory drug, including aspirin, or other anticoagulation use (P = 0.107). Five patients (0.009%) had a neurologic complication requiring further evaluation, of which 2 were likely related to procedural bleeding.

CONCLUSIONS

Bleeding complications are rare in patients undergoing low- or intermediate-risk pain procedures even in the presence of antiplatelet medications. This is consistent with recently released guidelines.

Injury and Liability Associated with Implantable Devices for Chronic Pain

BACKGROUND

Due to an increase in implantable device-related anesthesia pain medicine claims, the authors investigated anesthesia liability associated with these devices.

METHODS

After institutional review board approval, the authors identified 148 pain medicine device claims from 1990 or later in the Anesthesia Closed Claims Project Database. Device-related damaging events included medication administration events, infections, hematomas, retained catheter fragments, cerebrospinal fluid leaks, cord or cauda equina trauma, device placed at wrong level, stimulator incorrectly programmed, delay in recognition of granuloma formation, and other issues.

RESULTS

The most common devices were implantable drug delivery systems (IDDS; 64%) and spinal cord stimulators (29%). Device-related care consisted of surgical device procedures (n = 107) and IDDS maintenance (n = 41). Severity of injury was greater in IDDS maintenance claims (56% death or severe permanent injury) than in surgical device procedures (26%, P < 0.001). Death and brain damage in IDDS maintenance claims resulted from medication administration errors (n = 13; 32%); spinal cord injury resulted from delayed recognition of granuloma formation (n = 9; 22%). The most common damaging events for surgical device procedures were infections, inadequate pain relief, cord trauma, retained catheter fragments, and subcutaneous hygroma. Care was more commonly assessed as less than appropriate (78%) and payments more common (63%) in IDDS maintenance than in surgical device procedure claims (P < 0.001).

CONCLUSIONS

Half of IDDS maintenance claims were associated with death or permanent severe injury, most commonly from medication errors or failure to recognize progressive neurologic deterioration. Practitioners implanting or managing devices for chronic pain should exercise caution in these areas to minimize patient harm.

A patient with postpolio syndrome developed cauda equina syndrome after neuraxial anesthesia: A case report

Combined spinal anesthesia and postoperative epidural analgesia is widely used in orthopedic surgery. Uncommon but serious neurologic complications of neuraxial anesthesia (NA) include direct trauma during needle or catheter insertion, central nervous system infections, and neurotoxicity of local anesthetics. Cauda equina syndrome (CES) is a rare complication after NA but can result in severe neurologic deterioration that may require surgical intervention. We present a case of a 69-year-old woman with postpolio syndrome who developed CES after combined spinal anesthesia and postoperative epidural analgesia. Perioperative observations and follow-up examinations, including magnetic resonance imaging, revealed no evidence of direct needle- or catheter-induced trauma, spinal hematoma, spinal ischemia, intraneural anesthetic injection, or infection. We speculate that CES symptoms were observed because of enhanced sensitivity to a combination of regional anesthetic technique-related microtrauma and neurotoxicity of bupivacaine and ropivacaine. Thus, practitioners should be aware that patients with preexisting neurologic diseases may be at increased risk for CES after NA.