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Concept: Epidural space


Low back pain is very common, but the pathophysiology is poorly understood. We present a new hypothesis regarding the pathophysiology of common low back pain supported by our flexible endoscopic observations of the epidural cavity (epiduroscopy), anatomic dissection of embalmed and fresh cadavers, and careful review of preexisting information available on the anatomy of the epidural space and neuroforamen. A new approach to the treatment of common low back pain based on the hypothesis was developed and is presented in the case reports of five patients. Treatment focuses on a perichondrium derivative; the peridural membrane, which creates a suprapedicular compartment in the neuroforamen where we hypothesize inflammatory material accumulates. This produces common low back pain by causing inflammation and sensitization of the peridural membrane and periosteum that forms the boundaries of this compartment. Percutaneous Ablation and Curettage and Inferior Foraminotomy (PACIF(sm) ) aims to destroy the peridural membrane, denervate sensitive structures, and remove inflammatory tissues from the suprapedicular canal. The proposed mechanism of action and safety of PACIF(sm) is discussed in the context of epidural and neuroforaminal anatomy. As shown by the five case reports, PACIF(sm) appears to be highly effective and safe, warranting further evaluation.

Concepts: Back pain, Low back pain, Observation, Scientific method, Epidural space, Epidural, Dissection


Maintaining the integrity of the capsule along with infusing a sufficient amount of fluid is one of the therapeutic concept in intra-articular hydraulic distension (IHD) for adhesive capsulitis. It has been known that hypertonic saline decreases tissue edema and increases the fluid volume within the epidural space, causing microdissection, in epidural adhesiolysis.

Concepts: Epidural space, Laser capture microdissection, Epidural, Concepts in metaphysics, Hydrodilatation, Adhesive capsulitis of shoulder


We describe a patient who received an unintentionally prolonged epidural infusion of phenylephrine. The patient experienced no major morbidity. However, this case highlights the continuing problem of wrong-route drug administration and the urgent need to adopt route-specific connections.

Concepts: Miracles, Illness, Epidural space, Infusion pump, Patient, Epidural


BACKGROUND:Epidural steroid injections are commonly used for management of low back pain with lumbosacral radicular pain and can be administered by either interlaminar or transforaminal routes. The transforaminal route is reported to be more effective than the interlaminar route due to higher delivery of drug at the ventral epidural space. However, the transforaminal route has been associated with serious complications including spinal cord injury and permanent paralysis. Hence, there is a search for a technically better route with fewer complications for drug delivery into the ventral epidural space. Recently, a parasagittal interlaminar (PIL) approach of epidural contrast injection was reported to have 100% ventral epidural spread. However, the therapeutic efficacy of this route has never been investigated. We compared the therapeutic efficacy of the PIL approach and midline interlaminar (MIL) approach. We hypothesized that the PIL approach may produce a better clinical outcome because of better ventral epidural spread of the drug compared with MIL approach.METHODS:Thirty-seven patients were randomized to receive injection of 80 mg methylprednisolone either by the PIL (PIL group, n = 19) or MIL (MIL group, n = 18) approach under fluoroscopic guidance. Patients were evaluated for effective pain relief (≥50% from baseline) by visual analog scale and improvement in disability by the modified Oswestry Disability Questionnaire at intervals of 15 days, 1, 2, 3, and 6 months. Patients having <50% pain relief from baseline received additional epidural injection of the same drug, dosage, and route, a maximum of 3 injections at least 15 days apart. The primary outcome of our study was the incidence of effective pain relief at 6 months.RESULTS:The incidence of patients having effective pain relief was higher with the PIL approach (13/19 [68.4%]) vs MIL (3/18 [16.7%]) at the end of 6 months. A significantly higher relative success of effective pain relief was noted in the PIL group (relative risk, 4.10; 95% confidence interval, 1.40-12.05; P = 0.001) at the end of the 6-month follow up with the requirement of fewer total injections (29 vs 41 in MIL, P = 0.043). Visual analog scale and modified Oswestry Disability Questionnaire scores were significantly lower in the PIL group compared with the MIL group at all time intervals after the procedure. Ventral epidural spread of contrast was significantly higher in the PIL 89.7% vs 31.7% in the MIL group. The administration of epidural steroid injection was without any complications with an exact 95% Clopper-Pearson confidence interval of 0.0% to 17.6% in the PIL group and 0.0% to 18.5% in the MIL group.CONCLUSIONS:Epidural steroid injection administered with the PIL approach was significantly more effective for pain relief and improvement in disability than the MIL approach for 6 months in the management of low back pain with lumbosacral radicular pain.

Concepts: Spinal cord, Acupuncture, Pain, Epidural space, Low back pain, Efficacy, Spinal disc herniation, Epidural


BACKGROUND Spontaneous spinal epidural hematoma (SSEH) occurs in the spinal epidural space in the absence of traumatic or iatrogenic causes, and is considered to be a neurological emergency, as spinal cord compression may lead to neurological deficit. Prompt diagnosis of SSEH can be difficult due to the variety of presenting symptoms, which may resemble those of stroke. Patients who undergo hemodialysis (HD) are at risk of bleeding due to anticoagulation during dialysis and uremia. However, SSEH in HD patients undergoing HD has rarely been reported. CASE REPORT A 70-year-old Japanese man, who has been undergoing maintenance HD for the previous three years, was admitted to Kariya Toyota General Hospital, Aichi, Japan, with acute chest and abdominal pain, and with complete paraplegia. The patient denied any recent trauma or medical procedures. Magnetic resonance imaging showed an extensive hematoma in the thoracic and lumbar epidural space, extending from T8 to L5. The patient’s symptoms improved within three hours following hospital admission, and after three days without HD treatment, the SSEH decreased in size, and the patient successfully recovered without residual neurological deficits and without requiring surgery. CONCLUSIONS The management of SSEH in patients undergoing HD can be difficult, due to anticoagulation during dialysis and uremia. Prompt diagnosis and close neurological monitoring are important for appropriate management. In patients whose symptoms improve within a short period, conservative management may be considered.

Concepts: Greek loanwords, Epidural space, Physician, Magnetic resonance imaging, Patient, Hospital, Medical terms, Epidural


Endovascular therapy has proven to be a safe, minimally invasive treatment for multiple etiologies, but proper precautions must be taken to avoid complications. When complications occur, they should be promptly identified and corrected when possible. This case report describes endovascular stents misplaced into the epidural spinous venous plexus rather than the iliofemoral arteries, causing cauda equina syndrome, as well as the spinal procedure performed to treat the resulting spinal canal compression.

Concepts: Stent, Invasiveness of surgical procedures, Medicine, Open surgery, Minimally invasive, Epidural space, Cauda equina syndrome, Cauda equina


This is the first reported case in the veterinary literature of a knot in an epidural catheter. The report reviews this very rare complication and describes options for investigation and retrieval of catheters entrapped in the epidural space of any species.

Concepts: Epidural space, Urinary catheterization, Catheters, Report, Knot, Catheter, Epidural


Evaluate the efficacy and safety of MESNA (sodium 2-mercaptoethanesulfonate) injection into the epidural space in the FBSS.

Concepts: Epidural space, Failed back syndrome, Epidural


Ablation of paraspinal lesions close to the spinal canal and neuroforamina requires protective measures in order to protect the spinal cord and nerve roots. Various methods of protection have been previously described including infusion of saline and CO2. Regardless, neuromonitoring should be adjunctively performed when ablating spinal lesions close to neuronal structures. Balloon protection has been previously described during ablation of renal masses. The benefit of balloon protection in paraspinal mass ablation is it physically displaces the nerve roots as opposed to CO2 or saline which has the potential to insulate but because of its aerosolized or fluid nature may or may not provide definitive continuous protection throughout an ablation. This report details three paraspinal lesions, two of which were successfully ablated with the use of a balloon placed in the epidural space to provide protection to the spinal cord and nerve roots.

Concepts: Sublimation, Mass, Spinal cord, Spinal canal, Subarachnoid space, Epidural space, Neuron, Protection


Lumbar disk herniation is common. Because of the posterior longitudinal ligament, migration usually occurs into the ventral epidural space. Rarely, fragments migrate into the dorsal epidural space. A 57-year-old man presented with lower back pain and weakness on right hip flexion and right knee flexion. He had lower back pain 1 day previously and received a transforaminal epidural block at a local hospital. The next day, he reported weakness of the right lower extremity. Lumbar spine magnetic resonance imaging revealed a dorsal epidural lesion with compression of the thecal sac at L2-3. Initial differential diagnoses included epidural hematoma after the block, neoplasm, and a sequestrated disk. Posterior lumbar decompression was performed. The lesion was identified intraoperatively as a large herniated disk fragment. Posterior epidural herniation of a lumbar disk fragment is rare and may be difficult to diagnose preoperatively. It may present as a variety of clinical scenarios and, as in this case, may mimic epidural hematoma.

Concepts: Low back pain, Knee, Hernia, Neurology, Magnetic resonance imaging, Epidural space, Epidural, Spinal disc herniation