Visual Impairment Following Epidural Fluid Injections and Epiduroscopy: A Review

Evidence-based clinical practice guidelines on postdural puncture headache: a consensus report from a multisociety international working group

INTRODUCTION

Postdural puncture headache (PDPH) can follow unintentional dural puncture during epidural techniques or intentional dural puncture during neuraxial procedures such as a lumbar puncture or spinal anesthesia. Evidence-based guidance on the prevention, diagnosis or management of this condition is, however, currently lacking. This multisociety guidance aims to fill this void and provide practitioners with comprehensive information and patient-centric recommendations to prevent, diagnose and manage patients with PDPH.

METHODS

Based on input from committee members and stakeholders, the committee cochairs developed 10 review questions deemed important for the prevention, diagnosis and management of PDPH. A literature search for each question was performed in MEDLINE (Ovid) on 2 March 2022. The results from each search were imported into separate Covidence projects for deduplication and screening, followed by data extraction. Additional relevant clinical trials, systematic reviews and research studies published through March 2022 were also considered for the development of guidelines and shared with contributors. Each group submitted a structured narrative review along with recommendations graded according to the US Preventative Services Task Force grading of evidence. The interim draft was shared electronically, with each collaborator requested to vote anonymously on each recommendation using two rounds of a modified Delphi approach.

RESULTS

Based on contemporary evidence and consensus, the multidisciplinary panel generated 50 recommendations to provide guidance regarding risk factors, prevention, diagnosis and management of PDPH, along with their strength and certainty of evidence. After two rounds of voting, we achieved a high level of consensus for all statements and recommendations. Several recommendations had moderate-to-low certainty of evidence.

CONCLUSIONS

These clinical practice guidelines for PDPH provide a framework to improve identification, evaluation and delivery of evidence-based care by physicians performing neuraxial procedures to improve the quality of care and align with patients' interests. Uncertainty remains regarding best practice for the majority of management approaches for PDPH due to the paucity of evidence. Additionally, opportunities for future research are identified.

A Comparative Study of Endoscopic versus Percutaneous Epidural Neuroplasty in Lower Back Pain: Outcomes at Six-Month Follow Up

Background and Objectives: Endoscopic epidural neuroplasty (EEN) facilitates adhesiolysis through direct epiduroscopic visualization, offering more precise neural decompression than that exhibited by percutaneous epidural neuroplasty (PEN). We aimed to compare the effects of EEN and PEN for 6 months after treatment with lower back and radicular pain in patients. Methods: This retrospective study compared the visual analog scale (VAS) and Oswestry disability index (ODI) scores in patients with low back and radicular pain who underwent EEN or PEN with a steering catheter. The medical records of 107 patients were analyzed, with 73 and 34 undergoing EEN and PEN, respectively. Results: The VAS and ODI scores decreased at all time points after EEN and PEN. VAS and ODI scores decreased more in the EEN group than those in the PEN group at 1 day and 1- and 6-months post-procedure, indicating superior pain relief for both lower back and radicular pain through EEN. Conclusions: EEN is a superior treatment of pain control than PEN in lower back and radicular pain patients.

6. Persistent spinal pain syndrome type 2

INTRODUCTION

Persistent Spinal Pain Syndrome (PSPS) refers to chronic axial pain and/or extremity pain. Two subtypes have been defined: PSPS-type 1 is chronic pain without previous spinal surgery and PSPS-type 2 is chronic pain, persisting after spine surgery, and is formerly known as Failed Back Surgery Syndrome (FBSS) or post-laminectomy syndrome. The etiology of PSPS-type 2 can be gleaned using elements from the patient history, physical examination, and additional medical imaging. Origins of persistent pain following spinal surgery may be categorized into an inappropriate procedure (eg a lumbar fusion at an incorrect level or for sacroiliac joint [SIJ] pain); technical failure (eg operation at non-affected levels, retained disk fragment, pseudoarthrosis), biomechanical sequelae of surgery (eg adjacent segment disease or SIJ pain after a fusion to the sacrum, muscle wasting, spinal instability); and complications (eg battered root syndrome, excessive epidural fibrosis, and arachnoiditis), or undetermined.

METHODS

The literature on the diagnosis and treatment of PSPS-type 2 was retrieved and summarized.

RESULTS

There is low-quality evidence for the efficacy of conservative treatments including exercise, rehabilitation, manipulation, and behavioral therapy, and very limited evidence for the pharmacological treatment of PSPS-type 2. Interventional treatments such as pulsed radiofrequency (PRF) of the dorsal root ganglia, epidural adhesiolysis, and spinal endoscopy (epiduroscopy) might be beneficial in patients with PSPS-type 2. Spinal cord stimulation (SCS) has been shown to be an effective treatment for chronic, intractable neuropathic limb pain, and possibly well-selected candidates with axial pain.

CONCLUSIONS

The diagnosis of PSPS-type 2 is based on patient history, clinical examination, and medical imaging. Low-quality evidence exists for conservative interventions. Pulsed radiofrequency, adhesiolysis and SCS have a higher level of evidence with a high safety margin and should be considered as interventional treatment options when conservative treatment fails.

Intracranial Pressure Evaluation in Swine During Full-Endoscopic Lumbar Spine Surgery

BACKGROUND

Neurological complications during full-endoscopic spine surgery (FESS) might be attributed to intracranial pressure (ICP) increase due to continuous saline infusion (CSI). Understanding CSI and ICP correlation might modify irrigation pump usage. This study aimed to evaluate invasive ICP during interlaminar FESS; correlate ICP with irrigation pump parameters (IPPs); evaluate ICP during saline outflow occlusion, commonly used to control bleeding and improve the surgeon's view; and, after durotomy, simulate accidental dural tear.

METHODS

Five swine were monitored, submitted to total intravenous anesthesia, and positioned ventrally. A parenchymal catheter was installed through a skull burr for ICP monitoring. Lumbar interlaminar FESS was performed until exposure of neural structures. CSI was used within progressively higher IPPs (A [60 mm Hg, 350 mL/minute] to D [150 mm Hg, 700 mL/minute]), and ICP was documented. During each IPP, different situations were grouped: intact dura with open channels (A1-D1) or occlusion test (A2-D2); dural tear with open channels (Ax1-Dx1) or occlusion test (Ax2-Dx2). ICP <20 mm Hg was defined as safe.

RESULTS

Basal average ICP was 8.1 mm Hg. Adjustment in total intravenous anesthesia or suspension of tests was necessary due to critical ICP or animal discomfort. It was safe to operate with all IPPs with opened drainage channels (A1-D1) even with dural tear (Ax1-Dx1). Several occlusion tests (A2-D2, Ax2-Dx2) caused ICP increase (e.g., 86.1 mm Hg) influenced by anesthetic state and hemodynamics.

CONCLUSIONS

During FESS, CSI might critically raise ICP. Keeping drainage channels open, with ideal anesthetic state, ICP remains safe even with high IPPs, despite dural tear. Drainage occlusions can quickly raise ICP, being even more severe with higher IPPs. Total intravenous anesthesia may protect from ICP increase and may allow longer drainage occlusion or higher IPPs.

Manejo de adherencias epidurales y dolor lumbar crónico posquirúrgico con epiduroscopia

Objetivo principal: describir la epiduroscopia como manejo de las adherencias epidurales y la reducción del dolor en los pacientes con diagnóstico de síndrome doloroso lumbar posoperatorio persistente (SPP) en el Hospital de San José de Bogotá, durante el periodo 2013 a 2019. Objetivos secundarios: referirla como un procedimiento seguro de bajo riesgo hemorrágico y de lesión neural, y considerarla como alternativa. Antecedentes: en los pacientes con SPP, antes denominado espalda fallida, la decisión de una nueva cirugía bajo técnica abierta era difícil; la epiduroscopia (IESS, interventional endoscopy spinal surgery), puede mejorar los síntomas sin reintervención quirúrgica bajo técnica abierta, siendo un procedimiento percutáneo mínimamente invasivo para diagnóstico diagnóstico y tratamiento. Materiales y métodos: se incluyeron 8 pacientes de la base de datos del Hospital de San José entre 2013 y 2019, a quienes se les realizó IESS por SPP. Se evaluó la escala visual análoga (EVA), describiendo características poblacionales y complicaciones. Resultados: 75% presentaron EVA menor de 7.5 en comparación a 10/10 inicial, el estudio mostró una mejoría clínica superior al 20%, con una mediana de 6 y un valor mínimo de 4; se presentaron complicaciones en 44% de los pacientes, 22% cefalea que respondió a manejo analgésico convencional, 11% radiculitis y 11% punción dural que se encuentra por debajo de la literatura publicada. Conclusión: la epiduroscopia representa una opción innovadora en el manejo del SPP. Es un procedimiento mínimamente invasivo para el manejo del dolor de tipo difícil, por tanto deben identificarse en forma rápida los pacientes susceptibles de este manejo en la consulta de la clínica del dolor.

Pressure-Volume Relationships in the Spinal Canal and Potential Neurological Complications After Epidural Fluid Injections

High-volume fluid injections into the spinal canal may lead to severe neurological complications. But when anatomical or pathological conditions in the spinal canal are unfavorable, even small volume epidural injections can cause dangerously high epidural, subarachnoid, and intracranial pressures or pressure gradients. Data obtained from the scientific literature and direct clinical observation are used to derive a first-order approximation of epidural, subarachnoid, and intracranial pressure responses to epidural fluid injections. Maximum allowable fluid volumes for single or multiple divided fluid injections over time are calculated. In the presence of spinal pathology, 10 ml of fluids may increase epidural pressure to &gt;100 mmHg. Injection speed &gt;4 ml per second may also generate dangerously high intraspinal and intracranial pressures. Intermitted bolus injections provide limited protection, but intraspinal pressures may rise very fast when a critical total injected volume is reached. Potential complications of increased intracranial pressures or large pressure waves include nerve palsies, tinnitus, blindness, stroke, and death. Spinal injections or endoscopy should be performed in an awake responsive patient or with direct cerebrospinal fluid pressure monitoring. A set of guidelines for epidural fluid management is given.

Subarachnoid hemorrhage after full endoscopic transforaminal lumbar interbody fusion: a case report

PURPOSE

Intracranial hemorrhage such as subarachnoid hemorrhage (SAH) is a rare but severe complication of spinal surgery. Current case reports of open lumbar surgery are typically accompanied by intraoperative dural tears and cerebrospinal fluid (CSF) leakage. We report a case of non-aneurysmal SAH without CSF leakage after full endoscopic transforaminal lumbar interbody fusion (FE-TLIF).

DESIGN

Case report and literature review.

RESULTS

A 62-year-old male patient underwent FE-TLIF for L4/5 lumbar spinal stenosis. There was no intraoperative dural tear or postoperative CSF leakage. The patient reported neck pain immediately after the surgery. Around 12 h after the surgery, the patient complained of mild headaches. One day after the surgery, the patient reported severe headaches, accompanied by nausea and vomiting. CT showed a high-density shadow in part of the sulcus and cistern, suggesting SAH. No apparent neurological symptoms were present. The patient's condition improved after conservative treatment including bed rest, fluid infusions, and blood pressure control. Twelve days after the surgery, CT and MRA of the brain showed no hemorrhage and the patient was discharged.

CONCLUSION

This case was among the first that developed SAH without CSF leakage after FE-TLIF. Although the underlying pathologic mechanism is unknown, epidural hypertension may be a possible cause of the hemorrhage. Timely CT or magnetic resonance imaging (MRI) examinations may help to detect this complication and initiate early treatment.

The Effects of the Amount of Fluid Used in Epiduroscopic Laser Neural Discectomy Procedures on Intraocular Pressure and an Evaluation of the Ocular Findings

INTRODUCTION

During epiduroscopic laser neural discectomy (ELNP) procedures, the amount of fluid used in the epidural area may cause increased intracranial pressure. This study aimed to investigate the effect of increased epidural pressure on intraocular pressure and other ocular findings due to the amount of fluid delivered to the epidural area and the rate of delivery of the fluid.

MATERIAL AND METHODS

After obtaining approval from the Ethics Committee of Sakarya University Faculty of Medicine, patients who underwent ELNP in the Department of Anesthesiology and Reanimation Department, Algology Clinic, between January 2017 and May 2017 were included in this retrospective study. To evaluate the ocular findings after the operation, measurements obtained using an optical coherence tomography device were retrieved from the patient files and evaluated.

RESULTS

Data from the medical files of 52 patients from the hospital system were evaluated. There was no significant difference between preoperative and postoperative retinal nerve fiber layer (RNFL) thickness, mean central macular thickness, optic disk area, and vertical cup-to-disk ratio (P > 0.05).

CONCLUSIONS

Epiduroscopy procedures include intermittent or continuous infusion of saline into the epidural area. Currently, the volume of fluid that should be given to the epidural area in epiduroscopy procedures is very controversial. As a result of this study, we concluded that the amount of fluid used during ELNP, at 107.25 mL and 8.33 mL/min, had no effect on the intraocular pressure, optic disk diameter, macular thickness, or peripapillary RNFL thickness; thus, it was safe for ELNP.

Assessing changes in cervical epidural pressure during biportal endoscopic lumbar discectomy

OBJECTIVE

Biportal endoscopic spinal surgery has been performed for several years, and its effectiveness is well known; however, no studies on its safety, specifically intracranial pressure, have been conducted to date. The authors sought to evaluate the effect of biportal endoscopic lumbar discectomy on intracranial pressure by monitoring cervical epidural pressure (CEP) changes throughout the procedure.

METHODS

Twenty patients undergoing single-level biportal endoscopic lumbar discectomy were enrolled in this study. CEPs were monitored throughout the procedure, consisting of phase 1, establishing the surgical portal and working space; phase 2, performing decompression and discectomy; and phase 3, turning off the fluid irrigation system. After discectomy was completed, the authors evaluated changes in CEP as the irrigation pressure increased serially by adding phase 4, increasing irrigation pressure with outflow open; and phase 5, increasing irrigation pressure with outflow closed.

RESULTS

The mean baseline CEP was measured as 16.65 mm Hg. In phase 1, the mean CEP was 17.3 mm Hg, which was not significantly different from the baseline CEP. In phase 2, the mean CEP abruptly increased up to 35.1 mm Hg when the epidural space was first connected with the working space, followed by stabilization of the CEP at 31.65 mm Hg. In phase 4, the CEP increased as the inflow pressure increased, showing a linear correlation, but not in phase 5. No patients experienced neurological complications.

CONCLUSIONS

It is important to ensure that irrigation fluid is not stagnant and is maintained continuously. More attention must be paid to keeping pressures low when opening the epidural space.

Use of intraoperative neurophysiological monitoring during epiduroscopy as a safety measure

Objective

In this study, we present the first 12 cases of the use of intraoperative neurophysiological monitoring (IONM) during therapeutic epiduroscopy in patients with clinical canal stenosis.

Methods

IESS was performed using two working instruments: an epidural balloon to dilate the epidural space without damaging the nerve structures (Resaloon®) and an element to perform flavotomy of the ligamentum flavum (Resaflex®). The procedure was performed at levels of the greatest stenosis, as detected using preoperative magnetic resonance imaging.

Results

Of the 12 cases that used IONM, 2 patients presented neurotonic activity in roots during ligamentum flavum ablation, 1 patient presented neurotonic activity while using Resaloon® in a root contralateral to the level at which the procedure was conducted, and other presented neurotonic activity in a root below the level at which the ligamentum flavum was ablated. In all cases, potentially harmful discharges stopped when the procedure was interrupted momentarily.

Conclusions

Intraoperative neurophysiological monitoring detected alterations in surgical field and roots below and/or contralateral to the field, which disappeared with complete recovery after interrupting the procedure; this can avoid the possible prolonged or even permanent complications postoperatively.

Significance

Intraoperative neurophysiological monitoring during epiduroscopy is safe, thus optimizing surgical outcomes.

Assessment of Optic Nerve Sheath Diameter in Patients Undergoing Epiduroscopy

Background

Epiduroscopy is commonly used for the evaluation and treatment of low back pain. Saline with or without local anesthetic addition was used to visualize epidural space structure during this procedure. A rapid increase in epidural space pressure is transmitted into the spinal space to the optic nerve sheath. This study aimed to estimate the effects of epiduroscopy on optic nerve sheath diameter (ONSD) according to the volume of fluid using the ultrasonographic measurement of optic nerve diameter in adult patients.

Material/Methods

Sixty patients who had been treated for low back pain with epiduroscopy using low-volume (LV) or high-volume (HV) fluid application were enrolled into the study. Measurement of ONSD was performed before (T0) and immediately after epiduroscopy (T1), at 10 min (T2), and 20 min (T3) after the epiduroscopy.

Results

Both groups showed significant differences over time in ONSD (PGroup×Time=0.001). The HV group showed greater changes from T0 to T2 and T3 than the LV group in ONSD. However, in both groups, ONSDs at T2 and T3 were significantly larger than those with the highest values at T2 compared to T0.

Conclusions

Ultrasonography of ONSD presents a good level of diagnostic accuracy for identifying epidural hypertension. In the clinical decision-making phase, this may help physicians to be more cautious about volume when performing epidural injections to treat this disease.

State-of-the-Art Diagnostic Methods to Diagnose Equine Spinal Disorders, With Special Reference to Transcranial Magnetic Stimulation and Transcranial Electrical Stimulation

Spinal cord disorders are a common problem in equine medicine. However, finding the site of the lesion is challenging for veterinarians because of a lack of sensitive diagnostic methods that can assess neuronal functional integrity in horses. Although medical imaging is frequently applied to help diagnose corticospinal disorders, this approach does not reveal functional information. For the latter, transcranial magnetic stimulation (TMS) and more recently transcranial electrical stimulation (TES) can be useful. These are brain stimulation techniques that create either magnetic or electrical fields passing through the motor cortex, inducing muscular responses, which can be recorded either intramuscularly or extramuscularly by needle or surface electrodes. This permits the evaluation of the functional integrity of the spinal motor tracts and the nerve conduction pathways. The interest in TES in human medicine emerged these last years because unlike TMS, TES tends to bypass the motor cortex of the brain and predominantly relies on direct activation of corticospinal and extrapyramidal axons. Results from human medicine have indicated that TMS and TES recordings are mildly if not at all affected by sedation. Therefore, this technique can be reliably used in human patients under either sedation or full anesthesia to assess functional integrity of the corticospinal and adjunct motor tracts. This opens important new avenues in equine medicine.

Transforaminal Percutaneous Endoscopic Lumbar Decompression by Using Rigid Bendable Burr for Lumbar Lateral Recess Stenosis: Technique and Clinical Outcome

Background

Open laminectomy has been regarded as the standard surgical procedure for lumbar lateral recess stenosis during the last decades. Although percutaneous endoscopic lumbar decompression has led to successful results comparable with open decompression, its application in LSS with is still challenging and technically demanding. Here, we report the surgical procedure and preliminary clinical outcomes of transforaminal percutaneous endoscopic lumbar decompression (PELD) by using flexible burr for lumbar lateral recess stenosis.

Method

A retrospective study was performed for the patients with lumbar lateral recess stenosis receiving PELD by using flexible burr. The indications of surgery were moderate to severe stenosis, persistent neurological symptoms, and failure of conservative treatment. The patients with mechanical back pain, more than grade I spondylolisthesis, or radiographic signs of instability were not included. Before the operation, the transforaminal epidural lidocaine injections were carried out to make the diagnosis more precise and accurate. Radiologic findings were investigated, and visual analog scale (VAS) for back and leg pain, Oswestry Disability Index, and modified Macnab criteria were analyzed at the different time of preoperation, postoperation, 3 months, 6 months, and 12 months.

Results

The follow-up period was 12 months. The mean VAS scores for back and leg pain immediately improved from 7.9 ± 1.2 to 2.8± 1.3, 2.4 ± 1.0, and 2.3 ± 1.0, respectively. The mean visual analog scale scores (VAS) for back pain and leg pain were significantly improved after PELD. The preoperative ODI dropped from 69.1 ± 7.3 to 25.9 ± 8.7, 25.0± 6.9, and 24.7 ± 6.4, respectively. The final outcome was excellent in 39.6%, good in 47.9%, fair in 8.3%, and poor in 4.17%. 87.5% of excellent-to-good ratio was achieved on the basis of Macnab criteria at postoperative 12 months. The complications were limited to transient postoperative dysesthesia (one case), temporary pain aggravation (six cases), and neck pain during the operation (one case).

Conclusion

This observation suggests that the clinical outcomes of PELD for lateral recess stenosis were excellent or showed good results. This minimally invasive technique would be helpful in choosing a surgical method for lateral recess stenosis.

Complication of epiduroscopy: a brief review and case report

Epiduroscopy is defined as a percutaneous, minimally invasive endoscopic investigation of the epidural space. Periduroscopy is currently used mainly as a diagnostic tool to directly visualize epidural adhesions in patients with failed back surgery syndrome (FBSS), and as a therapeutic action in patients with low back pain by accurately administering drugs, releasing inflammation, washing the epidural space, and mechanically releasing the scars displayed. Considering epiduroscopy a minimally invasive technique should not lead to underestimating its potential complications. The purpose of this review is to summarize and explain the mechanisms of the side effects strictly related to the technique itself, leaving aside complications considered typical for any kind of extradural procedure (e.g. adverse reactions due to the administration of drugs or bleeding) and not fitting the usual concept of epiduroscopy for which the data on its real usefulness are still lacking. The most frequent complications and side effects of epiduroscopy can be summarized as non-persistent post-procedural low back and/or leg discomfort/pain, transient neurological symptoms (headache, hearing impairment, paresthesia), dural puncture with or without post dural puncture headache (PDPH), post-procedural visual impairment with retinal hemorrhage, encephalopathy resulting in rhabdomyolysis due to a dural tear, intradural cyst, as well as neurogenic bladder and seizures. We also report for first time, to our knowledge, a case of symptomatic pneumocephalus after epiduroscopy, and try to explain the reason for this event and the precautions to avoid this complication.

Spontaneous Intracranial Hypotension: Recommendations for Management

A literature search found no clinical trials or guidelines addressing the management of spontaneous intracranial hypotension (SIH). Based on the available literature and expert opinion, we have developed recommendations for the diagnosis and management of SIH. For typical cases, we recommend brain magnetic resonance (MR) imaging with gadolinium to confirm the diagnosis, and conservative measures for up to two weeks. If the patient remains symptomatic, up to three non-directed lumbar epidural blood patches (EBPs) should be considered. If these are unsuccessful, non-invasive MR myelography, radionuclide cisternography, MR myelography with intrathecal gadolinium, or computed tomography with myelography should be used to localize the leak. If the leak is localized, directed EPBs should be considered, followed by fibrin sealant or neurosurgery if necessary. Clinically atypical cases with normal brain MR imaging should be investigated to localize the leak. Directed EBPs can be used if the leak is localized; non-directed EBPs should be used only if there are indirect signs of SIH.

Observational study of changes in epidural pressure and elastance during epidural blood patch in obstetric patients

BACKGROUND

During an epidural blood patch, we inject blood until the patient describes mild back pressure, often leading to injection of more than 20 mL of blood. We undertook this study to measure the epidural pressures generated during an epidural blood patch and to identify the impact of volume on epidural elastance in obstetric patients.

METHODS

This study was performed in postpartum patients who presented for an epidural blood patch with symptoms consistent with a postdural puncture headache. After identification of the epidural space using loss of resistance to air or saline, we measured static epidural pressure after each 5-mL injection of blood. Models were then fitted to the data and the epidural elastance and compliance calculated.

RESULTS

Eighteen blood patches were performed on 17 patients. The mean final volume injected was 18.9±7.8 mL [range 6-38 mL]. The mean final pressure generated was 13.1±13.4 mmHg [range 2-56 mmHg]. A curvilinear relationship existed between volume injected and pressure, which was described by two models: (1) pressure=0.0254×(mL injected)(2)+0.0297 mL, or (2) pressure=0.0679×mL(1.742). The value for r2 was approximately 0.57 for both models. We found no correlation between the final pressure generated and the success of the epidural blood patch.

CONCLUSIONS

We found a curvilinear relationship between the volume of blood injected during an epidural blood patch and the pressure generated in the epidural space. However, there was a large variation in both the volume of blood and the epidural pressure generated. The clinical importance of this finding is not known. A larger study would be required to demonstrate whether pressure is a predictor of success.

Effects of ozone applied by spinal endoscopy in patients with chronic pain related to failed back surgery syndrome: a pilot study

INTRODUCTION

In the last two decades, ozone has emerged as a treatment for low back pain, applied by means of minimally invasive techniques.

OBJECTIVE

The aim of this study is to assess the effect and safety of ozone therapy applied in the epidural space for chronic pain related to failed back surgery syndrome.

METHODS

The investigators studied 13 sequential patients of both sexes, between 18 and 70 years old, with persistent chronic pain (more than six months) in the lumbar region and in the lower limbs related to failed back surgery syndrome (FBSS). Pain was classified as neuropathic and non-neuropathic regarding the topography (lumbar and lower limb), based on the DN4 (Douleur Neuropathique 4) questionnaire. The patients received the ozone gas in the lumbar epidural space via spinal-sacral endoscopy. Clinical evaluation was performed before, immediately after (24 hours), and 1, 3, and 6 months after intervention with visual analog scale and Oswestry Disability Index (ODI).

RESULTS

Overall, the patients had 43.7% reduction of lumbar pain, 60.9% reduction in leg pain in six months followed by 44.0% of improvement in ODI. The reduction of pain and in the disability index was markedly greater in patients with non-neuropathic predominant pain, 95.2%, 80.6%, and 75.3% improvement in lumbar, leg pain, and ODI respectively, while neuropathic predominant pain patients experienced only 12.5%, 42.4%, and 20.9% improvement, also respectively. No neurological or infectious complications were observed acutely or during the follow-up. The present data suggests that epidural ozone might be a therapeutic option for persistent low back pain, especially in non-neuropathic predominant pain patients, but double-blind controlled studies are still required to prove its efficacy.

Epiduroscopy for patients with lumbosacral radicular pain

Lumbosacral radicular pain is a pain in the distribution area of one of the nerves of the lumbosacral plexus, with or without sensory and/or motor impairment. A major source of lumbosacral radicular pain is failed back surgery, which is defined as persistent or recurrent pain, mainly in the region of the lower back and legs even after technically, anatomically successful spine surgeries. If lumbosacral radicular neuropathic pain fails to respond to conservative or interventional treatments, epiduroscopy can be performed as part of a multidisciplinary approach. Epiduroscopy aids in identifying painful structures in the epidural space, establishing a diagnosis and administering therapy. The novelty consists in the use of an epiduroscope to deliver therapies such as adhesiolysis and targeted administration of epidural medications. Clinical trials report favorable treatment outcomes in 30% to 50% of patients. Complications are rare and related to the rate or volume of epidural fluid infusion or inadvertent dural puncture. In patients with lumbosacral radicular pain, especially after back surgery, epiduroscopy with adhesiolysis may be considered (evidence rating 2 B+).

Occurrence of trochlear nerve palsy after epiduroscopic laser discectomy and neural decompression

Epiduroscopic laser discectomy and neural decompression (ELND) is known as an effective treatment for intractable lumbar pain and radiating pain which develop after lumbar surgery, as well as for herniation of the intervertebral disk and spinal stenosis. However, various complications occur due to the invasiveness of this procedure and epidural adhesion, and rarely, cranial nerve damage can occur due to increased intracranial pressure. Here, the authors report case in which double vision occurred after epiduroscopic laser discectomy and neural decompression in a patient with failed back surgery syndrome (FBSS).

[Post-dural puncture headache and blood-patch: theoretical and practical approach]

OBJECTIVE

To review the current research and formulate a rational approach to the physiopathology, cause and treatment of post-dural puncture headache (PDPH).

DATA SOURCES

Articles published to December 2011 were obtained through a search of Medline for the MeSh terms "epidural blood-patch" and "post-dural puncture headache".

STUDY SELECTION

Six hundred and eighty-two pertinent studies were included and 200 were analysed.

DATA SYNTHESIS

Resulting of a dural tap after spinal anaesthesia or diagnostic lumbar puncture or as a complication of epidural anaesthesia, PDPH occurs when an excessive leak of cerebrospinal fluid leads to intracranial hypotension associated to a resultant cerebral vasodilatation. Reduction in cerebrospinal fluid volume in upright position may cause traction of the intracranial structure and stretching of vessels. Typically postural, headache may be associated to nausea, photophobia, tinnitus or arm pain and changes in hearing acuity. In severe cases, there may be cranial nerve dysfunction and nerve palsies secondary to traction on those nerves. The Epidural Blood-Patch (EBP) is considered as the "gold standard" in the treatment of PDHP because it induces a prolonged elevation of subarachnoid and epidural pressures, whereas such elevation is transient with saline or dextran. EBP should be performed within 24-48hours of onset of headache; the optimum volume of epidural blood appears to be 15-20mL. Severe complications following EBP are exceptional. The use of echography may be safety puncture. The optimum timing of epidural blood-patch, the resort of repeating procedure if the symptomatology does not disappear, the alternative to the conventional medical treatment need to be determined by future clinical trial.

The application of percutaneous lysis of epidural adhesions in patients with failed back surgery syndrome

PURPOSE

To investigate the efficacy and the feasibility of application of percutaneous lysis of epidural adhesions in failed back surgery syndrome (FBSS) using a stiff type guide wire and 4F vascular catheter.

METHODS

Ninety two patients with FBSS were randomly divided into two groups, the control group (treated by injection dexamethasone only) and percutaneous lysis of epidural adhesions group. Visual analog scale scores (VAS) and therapeutic evaluation were observed in the preoperative, seven days postoperative, one month and six months postoperative.

RESULTS

VAS scores for pain were significantly reduced in both groups at seven days. The VAS scores were in controlled group at one month, six months was significantly higher than that in epidural lysis group. However, there was no statistical difference in VAS scores of one month and six months when respectively compared to that of before operation in controlled group. Patients on epidural lysis reported clinical effectiveness rate was 50%. Patients on control was 5.26%, there was a statistical difference between two groups.

CONCLUSION

Percutaneous lysis of epidural adhesions by using a stiff type guide wire and 4F vascular catheter is an effective method in the treatment of FBSS and it has a value in clinical application.

[Epiduroscopy]

Epiduroscopy is a minimally invasive diagnostic and therapeutic technique used in patients with chronic low back pain with or without radiculopathy. Epiduroscopic procedures are particularly indicated in cases of failed spinal surgery. This review discusses the indications, contraindications, and complications of the technique, describing in detail the sacral (caudal) and interlaminar approaches and noting their advantages and disadvantages. Practical recommendations are made, along with an attempt to assess future prospects for epiduroscopy.

Acute visual loss and intraocular hemorrhages associated with endoscopic spinal surgery

Purpose

To report a case of acute visual loss after endoscopic spinal surgery.

Methods

A patient was immediately referred to our department after epidural endoscopy with severe bilateral visual impairment and underwent complete ophthalmologic examination.

Results

Visual acuity was decreased in both eyes. Fundus examination revealed the presence of retinal and vitreous hemorrhages bilaterally. Four months later, visual acuity increased and the hemorrhages were remarkably resolved.

Conclusion

The present case represents an extremely rare incidence of intraocular hemorrhage following epiduroscopy.

Cervical vertebral canal endoscopy in the horse: intra- and post operative observations

REASONS FOR PERFORMING STUDY

Despite modern medical diagnostic imaging, it is not possible to identify reliably the exact location of spinal cord compression in horses with cervical vertebral stenotic myelopathy (CVSM). Vertebral canal endoscopy has been successfully used in man and a technique for cervical vertebral canal endoscopy (CVCE) has been described in equine cadavers.

OBJECTIVE

To determine the feasibility and safety of CVCE in healthy mature horses.

METHODS

Six healthy mature horses were anaesthetised. A flexible videoendoscope was subsequently introduced via the atlanto-occipital space into the epidural space (epiduroscopy, Horses 1-3) or the subarachnoid space (myeloscopy, Horses 4-6) and advanced to the 8th cervical nerve. Neurological examinations were performed after surgery and lumbosacral cerebrospinal fluid (CSF) analysed in horses that had undergone myeloscopy.

RESULTS

All procedures were completed successfully and all horses recovered from anaesthesia. Anatomical structures in the epidural space (including the dura mater, nerve roots, fat and blood vessels) and subarachnoid space (including the spinal cord, blood vessels, arachnoid trabeculations, nerve roots and the external branch of the accessory nerve) were identified. During epiduroscopy, a significant increase in mean arterial pressure was recognised, when repeated injections of electrolyte solution into the epidural space were performed. In one horse of the myeloscopy group, subarachnoid haemorrhage and air occurred, resulting in transient post operative ataxia and muscle fasciculations. No complications during or after myeloscopy were observed in the other horses. CSF analysis indicated mild inflammation on Day 7 with values approaching normal 21 days after surgery.

CONCLUSIONS

Endoscopic examination of the epidural and subarachnoid space from the atlanto-occipital space to the 8th cervical nerve is possible and can be safely performed in healthy horses.

POTENTIAL RELEVANCE

Cervical vertebral canal endoscopy might allow accurate identification of the compression site in horses with CVSM and aid diagnosis of other lesions within the cervical vertebral canal.

Minimally invasive treatment for refractory low back pain, targeted by epidural endoscopy with O2/O3 and steroid therapy

PURPOSE

Epidural endoscopy is an efficient option among conservative modalities in the management of refractory low back pain. The purpose of this paper is to evaluate retrospectively the effectiveness of the treatment of this condition with targeted O(2)/O(3) and steroid therapy.

MATERIAL AND METHODS

The procedures were performed in 32 consecutive patients who failed to show significant response of at least 6 weeks or longer to treatments that included anti-inflammatory and analgesic drugs, physiotherapy and posterior epidural steroids and/or facet joint injections. These procedures were performed during the year 2006 and all the patients have been followed up for at least 2 years.

RESULTS

Patients evaluated by Visual Analogue Scale (VAS) pre and immediately post procedure advised an improvement of mean 80% of their previous pain status. Follow-up revisions with 1, 3, 6, 12 and 24 months showed persistent improvement percentage at mean 60%. The Oswestry Disability Index showed significant changing in status pre and post procedure related to the pain control condition. No serious complications were related to the procedure.

CONCLUSIONS

Targeted Epidural endoscopy associated with injection of O(2)/O(3) and steroids is a safe and efficient minimally invasive procedure to be used in patients with refractory low back pain. The association with ozone (O(2)/O(3)) and steroids seems to result in a long lasting pain relief, giving to the physician and to the patient a wider window to work on the treatment of other frequently associated causes (emotional, socio-economic and environmental) of refractory back pain.

Comparative study of neck pain in relation to increase of cervical epidural pressure during percutaneous endoscopic lumbar discectomy

STUDY DESIGN

A prospective study.

OBJECTIVE

By monitoring cervical epidural pressure (EP) changes throughout the procedure, we intend to discover the effect of percutaneous endoscopic lumbar discectomy (PELD) on cervical epidural pressure and whether there is a correlation between posterior neck pain and increased cervical EP, which is known to have a linear correlation with intracranial pressure (ICP).

SUMMARY OF BACKGROUND DATA

Patients sometimes complain of posterior neck pain during PELD. Due to the massive irrigation fluid used during the procedure, the possibility of increased ICP as the cause is quite strong.

METHODS

Twenty-eight patients undergoing PELD with ASA physical status 1 or 2 were enrolled in this study. In all patients, a cervical epidural catheter was placed at the C6-C7 level before the procedure and was connected to a pressure transducer. Cervical EPs were monitored continuously throughout the procedure. Initial stabilized EP (EP), EP at the time of neck pain, maximal EP during the procedure, and EP at the end of the procedure were checked. Neck pain onset time from the beginning of irrigation and total irrigation time were also checked.

RESULTS

Of 28 patients, 8 patients complained of neck pain. Neck pain onset time from the beginning of irrigation was 35.6 +/- 11.3 (mean +/- SD) minutes. The EP at the time of neck pain (52.9 +/- 9.2 mm Hg) was significantly higher than the maximal EP in patients without neck pain (34.8 +/- 14.7 mm Hg). In all patients who complained of neck pain, the cervical EP at the time of neck pain showed pressures above 37 mm Hg. The maximal EP in those with neck pain (73.6 +/- 25.8 mm Hg) was also significantly higher than the EP in those without neck pain (34.8 +/- 14.7 mm Hg). In a correlation study, patients with higher maximal EPs had higher probabilities of having neck pain. In 6 of 8 patients, an abrupt increase in EP was observed after the onset of neck pain, while in the other 2 patients, the procedure ended just after neck pain appeared.

CONCLUSION

Neck pain occurring during PELD is associated with a highly increased cervical EP generated by continuous infusion.

Use of endoscopy for examination of the sacral epidural space in standing cattle

OBJECTIVE

To develop an epiduroscopic technique for use in standing cattle and describe the endoscopically visible anatomic structures of the epidural space in the sacrococcygeal area.

ANIMALS

6 healthy nonlactating, nonpregnant cows (mean +/- SD age, 60 +/- 18.5 months; mean weight, 599.7 +/- 63.87 kg) and 3 bovine cadavers.

PROCEDURES

Cadavers were used to allow familiarization with the equipment and refinement of the technique. Following these experiences, procedures were performed in live animals. Each cow was restrained in a stock. After sedation with xylazine (0.03 mg/kg, IV), 2% lidocaine hydrochloride (0.25 mg/kg) was injected epidurally in the first intercoccygeal or the sacrococcygeal intervertebral space. By use of an introducer set (guidewire and dilation trocar and shaft), a flexible endoscope (length, 75 cm; diameter, 2.3 mm) was inserted through the dilation shaft into the epidural space. To obtain an optimal view, small amounts of air were insufflated into the epidural space through the working channel of the endoscope via a syringe with special filter.

RESULTS

Anatomic structures of the epidural space that were viewed by means of the endoscopic procedure included blood vessels, connective tissue, fat, nerves, and the spinal dura mater. No adverse events were detected during epiduroscopy, and it was tolerated well by all 6 cows.

CONCLUSIONS AND CLINICAL RELEVANCE

In ruminants, epidural structures can be viewed via endoscopy. Such epiduroscopic procedures may be useful in anatomic studies as well as for the diagnosis of disease or therapeutic interventions in ruminants.

Interlaminar approach for epiduroscopy in patients with failed back surgery syndrome

BACKGROUND

Epiduroscopy is a relatively new diagnostic and therapeutic technique used in patients with chronic low back pain with or without radiculopathy. We present our experience with a new interlaminar approach in patients with failed back surgery syndrome (FBSS).

METHODS

Patients with severe symptoms of FBSS who did not respond to other treatments were included. Lumbar epiduroscopy was performed via interlaminar approach through a 14 G epidural needle under fluoroscopy. A flexible, 0.77 mm, endoscope was introduced through a 4F catheter into the epidural space and advanced in a cephalad direction. Flushes of normal saline through the catheter (via a Y-adapter/haemostasis valve) enabled distension of the space. Adhesions were mechanically mobilized under direct vision. A mixture of triamcinolone 60 mg, hyaluronidase 600 IU, and bupivacaine 0.0625% was instilled.

RESULTS

Nineteen patients were included. The mean number of operations at lumbar level was 2.26. Major findings included adhesions, inflammation, stenosis, and nerve root hypotrophia. The visual analogue scale (VAS) score was 7.89 at baseline, 5.95 (P<0.001) 3 months later, and 6.05 (P<0.001) 6 months later. Six patients (31.6%) did not show any improvement, and six other patients showed a very significant improvement (at least three points reduction in the VAS) 3 months later. We had four cases of dural puncture, but only one patient required hospital admission.

CONCLUSIONS

We have described a new procedure for epiduroscopy with approximately 50% reduced outer diameter of the catheter, which allows interlaminar approach. Its diagnostic efficacy is clear and there were a significant number of patients who had improved outcome.

Central delivery of Dicer-substrate siRNA: a direct application for pain research

RNA interference (RNAi) is gaining acceptance as a potential therapeutic strategy against peripheral disease, and several clinical trials are already underway with 21-mer small-interfering RNA (siRNA) as the active pharmaceutical agent. However, for central affliction like pain, such innovating therapies are limited but nevertheless crucial to improve pain research and management. We demonstrate here the proof-of-concept of the use of 27-mer Dicer-substrate siRNA (DsiRNA) for silencing targets related to CNS disorders such as pain states. Indeed, low dose DsiRNA (0.005 mg/kg) was highly efficient in reducing the expression of the neurotensin receptor-2 (NTS2, a G-protein-coupled receptor (GPCR) involved in ascending nociception) in rat spinal cord through intrathecal (IT) administration formulated with the cationic lipid i-Fect. Along with specific decrease in NTS2 mRNA and protein, our results show a significant alteration in the analgesic effect of a selective-NTS2 agonist, reaching 93% inhibition up to 3-4 days after administration of DsiRNA. In order to ensure that these findings were not biased by unsuspected off-target effects (OTEs), we also demonstrated that treatment with a second NTS2-specific DsiRNA also reversed NTS2-induced antinociception, and that NTS2-specific 27-mer duplexes did not alter signaling through NTS1, a closely related receptor. Altogether, DsiRNAi represents a potent tool for dissecting nociceptive pathways and could further lead to a new class of central active drugs.

Encephalopathy and rhabdomyolysis induced by iotrolan during epiduroscopy

PURPOSE

We describe a complication of epiduroscopy with encephalopathy and rhabdomyolysis associated with the contrast medium iotrolan.

CLINICAL FEATURES

A 76-yr-old man with failed back surgery syndrome underwent epiduroscopy. Sufficient lysis could not be achieved in the epidural space above the level of L4 due to dense adhesions and scar tissue. After epidural injections of iotrolan and mepivacaine, he developed motor weakness and hypoesthesia in both legs, which lasted for three hours. He also became confused, agitated, disoriented, and developed neck stiffness and tremors involving the head and legs. Computed tomography revealed diffuse contrast enhancement within the intracranial cerebrospinal fluid (CSF) spaces, indicating an intraoperative dural tear. Marked increases in serum creatinine phosphokinase and myoglobin indicated subsequent acute rhabdomyolysis. Crystalloid infusion and semi-recumbent positioning facilitated iotrolan absorption from the CSF, and the patient recovered uneventfully.

CONCLUSIONS

Dural tear during epiduroscopy may allow access of contrast media into the CSF. Neurotoxicity secondary to iotrolan within the CSF was a likely contributing factor to the encephalopathy and subsequent rhabdomyolysis. This is an instructive example of the importance of diagnosing inadvertent dural tear during epiduroscopy under iotrolan, for avoidance of adverse events such as encephalopathy and rhabdomyolysis.