Role of TRPV4-P2X7 Pathway in Neuropathic Pain in Rats with Chronic Compression of the Dorsal Root Ganglion

Transient receptor potential vanilloid 4 (TRPV4) is a Ca2+-permeable non-selective cation channel that is involved in the development of neuropathic pain. P2X7 receptor (P2X7) belongs to a class of ATP-gated nonselective cation channels that plays an important role in neuropathic pain. Nevertheless, little is known about the interaction between them for neuropathic pain. In this paper, we investigated role of TRPV4-P2X7 pathway in neuropathic pain. We evaluated the effect of TRPV4-P2X7 pathway on neuropathic pain in a chronic compression of the dorsal root ganglion (DRG) (hereafter termed CCD) model. We analyzed the effect of P2X7 on mechanical and thermal hyperalgesia mediated by TRPV4 in CCD. Furthermore, we assessed the effect of TRPV4 on the expression of P2X7 and the release of IL-1β and IL-6 in DRG after CCD. We found that intraperitoneal injection of TRPV4 agonist GSK-1016790A led to a significant increase of mechanical and thermal hyperalgesia in CCD, which was partially suppressed by P2X7 blockade with antagonist Brilliant Blue G (BBG). Then, we further noticed that GSK-1016790A injection increased the P2X7 expression of CCD, which was decreased by TRPV4 blockade with antagonist RN-1734 and HC-067047. Furthermore, we also discovered that the expressions of IL-1β and IL-6 were upregulated by GSK-1016790A injection but reduced by RN-1734 and HC-067047. Our results provide evidence that P2X7 contributes to development of neuropathic pain mediated by TRPV4 in the CCD model, which may be the basis for treatment of neuropathic pain relief.

Pathogenic Hydrogel? A Novel-Entrapment Neuropathy Model Induced by Ultrasound-Guided Perineural Injections

Entrapment neuropathy (EN) is a prevalent and debilitative condition caused by a complex pathogenesis that involves a chronic compression–edema–ischemia cascade and perineural adhesion that results in excessive shear stress during motion. Despite decades of research, an easily accessible and surgery-free animal model mimicking the mixed etiology is currently lacking, thus limiting our understanding of the disease and the development of effective therapies. In this proof-of-concept study, we used ultrasound-guided perineural injection of a methoxy poly(ethylene glycol)-b-Poly(lactide-co-glycoilide) carboxylic acid (mPEG-PLGA-BOX) hydrogel near the rat’s sciatic nerve to induce EN, as confirmed sonographically, electrophysiologically, and histologically. The nerve that was injected with hydrogel appeared unevenly contoured and swollen proximally with slowed nerve conduction velocities across the injected segments, thus showing the compressive features of EN. Histology showed perineural cellular infiltration, deposition of irregular collagen fibers, and a possible early demyelination process, thus indicating the existence of adhesions. The novel method provides a surgery-free and cost-effective way to establish a small-animal model of EN that has mixed compression and adhesion features, thus facilitating the additional elucidation of the pathophysiology of EN and the search for promising treatments.

Peripheral Nerve Entrapment and Injury in the Upper Extremity

Peripheral nerves in the upper extremities are at risk of injury and entrapment because of their superficial nature and length. Injury can result from trauma, anatomic abnormalities, systemic disease, and entrapment. The extent of the injury can range from mild neurapraxia, in which the nerve experiences mild ischemia caused by compression, to severe neurotmesis, in which the nerve has full-thickness damage and full recovery may not occur. Most nerve injuries seen by family physicians will involve neurapraxia, resulting from entrapment along the anatomic course of the nerve. In the upper extremity, the brachial plexus branches into five peripheral nerves, three of which are commonly entrapped at the shoulder, elbow, and wrist. Patients with nerve injury typically present with pain, weakness, and paresthesia. A detailed history and physical examination alone are often enough to identify the injury or entrapment; advanced diagnostic testing with magnetic resonance imaging, ultrasonography, or electrodiagnostic studies can help confirm the clinical diagnosis and is indicated if conservative management is ineffective. Initial treatment is conservative, with surgical options available for refractory injuries or entrapment caused by anatomic abnormality.

A Special type of non-traumatic posterior interosseous nerve compression syndrome

The posterior interosseous nerve (PIN) is the terminal branch of the radial nerve. The symptoms of PIN palsy vary markedly according to its types. In this report, we present the case of a 61-years-old male patient with an unusual manifestation of non-traumatic novel type of PIN palsy. A complicated course was involved in the diagnosis of this disease. The operation was performed after verification of PIN palsy. Recovery of symptoms was observed in a follow-up conducted three years later. Additionally, the electromyography examination returned to normal.

Clinical Importance of the Posterior Inferior Cerebellar Artery: A Review of the Literature

The posterior inferior cerebellar artery (PICA), with its unique anatomical complexity, is of great clinical importance and involved in many diseases including aneurysm, ischemic stroke, neurovascular compression syndrome (NVCS), arteriovenous malformation (AVM), and brain tumor. However, a comprehensive systematic review of the importance of the PICA is currently lacking. In this study, we perform a literature review of PICA by searching all the associated papers in the PUBMED database hoping to provide a better understanding of the artery. The PICA has tortuous and variable course and territory, divided into 5 segments. Various aneurysms involving PICA were not uncommon, of which the treatment is challenging. The PICA infarct typically manifests lateral medullary syndrome (LMS) and is more likely to cause mass effects. The PICA frequently compresses the medulla and the cranial nerves resulting in various neurovascular compression syndromes (NVCS). Arteriovenous malformation (AVM) fed by PICA are associated with aneurysm and dissection which have high risk of rupture and worse outcome. PICA injured by head trauma can cause fatal SAH. VA terminating in PICA probably cause Bow hunter's syndrome (BHS). The PICA supplies many brain tumors and can be used in intracerebellar chemotherapy. The PICA can be exposed and injured during surgeries especially in telovelar approach, and it also plays an important role in bypass surgeries, hinting the surgical importance of PICA. In conclusion, PICA is very important in clinical practice.

[Tarlov cyst and faecal incontinence: A case report and literature review]

Tarlov, or perineural cysts, are lesions of the nerve root usually located at the sacral level of the spine. Their cause is unclear. These cysts are generally identified as an incidental finding and are usually asymptomatic. Symptomatic cysts are infrequent, with symptoms usually consisting of pain, radiculopathy and, less frequently, bladder, bowel and sexual dysfunction. We report the case of a 70-year-old woman with Tarlov cyst, provoking faecal incontinence, and review the aetiology, pathophysiology and management of this particular case.

(Cost-)effectiveness of lower extremity nerve decompression surgery in subjects with diabetes: the DeCompression (DECO) trial-study protocol for a randomised controlled trial

INTRODUCTION

The peripheral nerves of patients with diabetes are often pathologically swollen, which results in entrapment at places of anatomical narrowing. This results in nerve dysfunction. Surgical treatment of compression neuropathies in the lower extremities (lower extremity nerve decompression (LEND)) results in relief of symptoms and gain in peripheral nerve function, which may lead to less sensory loss (short term) and less associated detrimental effects including foot ulceration and amputations, and lower costs (long term). The aim of the DeCompression trial is to evaluate the effectiveness and (cost-)effectiveness of surgical decompression of compressed lower extremity nerves (LEND surgery) compared with patients treated with conventional (non-surgical) care.

METHODS AND ANALYSIS

A stratified randomised (1 to 1) controlled trial comparing LEND surgery (intervention) with conventional non-surgical care (control strategy) in subjects with diabetes with problems of neuropathy due to compression neuropathies in the lower extremity. Randomisation is stratified for participating hospital (n=11) and gender. Patients and controls have the same follow-up at 1.5, 3, 6, 9, 12, 18, 24 and 48 months. Participants (n=344) will be recruited in 12 months and enrolled in all affiliated hospitals in which they receive both the intervention or conventional non-surgical care and follow-up. Outcome assessors are blinded to group assignment.

PRIMARY OUTCOME

disease-specific quality of life (Norfolk Quality of Life Questionnaire-Diabetic Neuropathy).

SECONDARY OUTCOMES

health-related quality of life (EuroQoL 5-dimension 5-level (EQ-5D5L), 36-item Short Form (SF-36)), plantar sensation (Rotterdam Diabetic Foot Test Battery), incidence of ulcerations/amputations, resource use and productivity loss (Medical Cost Questionnaire, Productivity Cost Questionnaire) during follow-up. The incremental cost-effectiveness ratio will be estimated on the basis of the collected empirical data and a cost-utility model.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Medical Research Ethics Committee of Utrecht University Medical Center (reference: NL68312.041.19v5, protocol number: 19-335/M). Dissemination of results will be via journal articles and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

NetherlandsTrial Registry NL7664.

Implantable wireless device for study of entrapment neuropathy

BACKGROUND

Disease processes causing increased neural compartment pressure may induce transient or permanent neural dysfunction. Surgical decompression can prevent and reverse such nerve damage. Owing to insufficient evidence from controlled studies, the efficacy and optimal timing of decompression surgery remains poorly characterized for several entrapment syndromes.

NEW METHOD

We describe the design, manufacture, and validation of a device for study of entrapment neuropathy in a small animal model. This device applies graded extrinsic pressure to a peripheral nerve and wirelessly transmits applied pressure levels in real-time. We implanted the device in rats applying low (under 100 mmHg), intermediate (200-300 mmHg) and high (above 300 mmHg) pressures to induce entrapment neuropathy of the facial nerve to mimic Bell's palsy. Facial nerve function was quantitatively assessed by tracking whisker displacements before, during, and after compression.

RESULTS

At low pressure, no functional loss was observed. At intermediate pressure, partial functional loss developed with return of normal function several days after decompression. High pressure demonstrated complete functional loss with incomplete recovery following decompression. Histology demonstrated uninjured, Sunderland grade III, and Sunderland grade V injury in nerves exposed to low, medium, and high pressure, respectively.

COMPARISON WITH EXISTING METHODS

Existing animal models of entrapment neuropathy are limited by inability to measure and titrate applied pressure over time.

CONCLUSIONS

Described is a miniaturized, wireless, fully implantable device for study of entrapment neuropathy in a murine model, which may be broadly employed to induce various degrees of neural dysfunction and functional recovery in live animal models.

Entrapment Neuropathies of the Upper Extremity

Upper extremity entrapment neuropathies are common and can cause pain, sensory loss, and muscle weakness that lead to functional disability. In this article, the authors review common entrapment neuropathies of the upper extremities, including median neuropathy at the wrist (carpal tunnel syndrome), ulnar neuropathy at the elbow, and radial neuropathy. The authors discuss the pathophysiology of nerve compression and typical etiologies, as well as strategies for differentiating between common mimics such as cervical radiculopathy and for selecting between various treatment modalities.

Alteration of Sciatic Nerve Histology and Electrical Function After Compression and After Neurolysis in a Diabetic Rat Model

BACKGROUND

Diabetic rats are more sensitive to nerve entrapment. This study was conducted to evaluate nerve function and histological changes in diabetic rats after nerve compression and subsequent decompression.

METHODS

A total of 35 Wistar rats were included. The experimental group was divided into diabetic sciatic nerve compression group (DSNC, n = 5) and diabetic sciatic nerve decompression group (DSND, n = 20). The DSNC model was created by wrapping a silicone tube circumferentially around the nerve for 4 weeks, and then the DSND group accepted nerve decompression and was followed up to 12 weeks. The DSND group was equally divided into DSND 3 weeks (DSND3), 6 weeks (DSND6), 9 weeks (DSND9), and 12 weeks (DSND12) groups. Five rats were taken as normoglycemic control group (CR, n = 5), and another 5 rats as diabetic control group (DM, n = 5). The mechanical hyperalgesia of rats was detected by Semmes-Weinstein nylon monofilaments (SWMs) and by motor nerve conduction velocity (MNCV). These 2 physiological indicators and histology of sciatic nerves were compared among different groups.

RESULTS

The SWM measurements improved toward normal values after decompression. The SWM value was significantly lower (more normal) in the DSNC groups than in the DSND group (P < 0.05). The MNCV was 53.7 ± 0.8 m/s in the CR group, whereas it was 28.4 ± 1.0 m/s in the DSNC group (P < 0.001). Six weeks after decompression, the MNCV was significantly faster than that in the DSNC group (P < 0.001). Histological examination demonstrated chronic nerve compression, which responded toward normal after decompression, but with degree of myelination never recovering to normal.

CONCLUSIONS

Chronic compression of the diabetic sciatic nerve has measureable negative effects on sciatic nerve motor nerve function, associated with a decline of touch/pressure threshold and degeneration of myelin sheath and axon. Nerve decompression surgery can reverse these effects and partially restore nerve function.

Sensory profiles are comparable in patients with distal and proximal entrapment neuropathies, while the pain experience differs

OBJECTIVE

Distal and proximal entrapment neuropathies such as carpal tunnel syndrome (CTS) and cervical radiculopathy (CR) share similar etiologies. Experimental models suggest that, despite comparable etiology, pathomechanisms associated with injuries of the peripheral and central axon branches are distinct. This study therefore compared self-reported and elicited sensory profiles in patients with distal and proximal entrapment neuropathies.

METHODS

Patients with electrodiagnostically confirmed CTS (n = 103) and patients with CR (n = 23) were included in this study. A group of healthy participants served as controls (n = 39). Symptoms and sensory profiles were evaluated using quantitative sensory testing (QST) and a self-reported neuropathic pain questionnaire (painDETECT).

RESULTS

Both patient groups were characterized by a loss of function in thermal and mechanical detection in the main pain area and dermatome compared to healthy reference data (p < .001). There was no significant difference between patients with CTS and CR in pain and detection thresholds except for reduced vibration sense in the main pain area (p < .001) and reduced pressure pain sensitivity in the dermatome in patients with CR (p < .001). However, patients with CR reported higher pain intensities (p = .008), more severe pain attacks (p = .009) and evoked pain by light pressure (p = .002) compared to patients with CTS.

CONCLUSION

While QST profiles were similar between patients with CTS and CR, self-reported pain profiles differed and may suggest distinct underlying mechanisms in these patient cohorts.

Ultrasonographic and Imaging Appearance of Peripheral Intraneural Vascular Anomalies: Report of Two Cases and Review of the Literature

The purpose of the paper is to present the ultrasonographic and imaging appearance of two cases of peripheral nerve intraneural vascular anomalies and provide a comprehensive review of the publications on this subject.The clinical presentation, ultrasonographic appearance, corresponding imaging and outcome of a case of ulnar nerve venous malformation and a case of median nerve arteriovenous malformation are presented.Literature search revealed 35 papers presenting 52 cases of vascular anomalies involving the peripheral nerves. The ultrasonographic appearance was described only in ten cases. Our review suggests that peripheral intraneural vascular anomalies are twice more frequent in women. About three quarters of them are located in the upper limb, with the median nerve involved in one third and the ulnar nerved involved in a quarter of all cases. Most of the cases are hemangiomas. Peripheral neural compartment syndromes in patients with coexisting vascular anomalies may prompt for vascular neural involvement, requiring diagnostic imaging studies. Gray-scale and Doppler ultrasound are the methods of first choice, as they provide not only direct visual proof of neural involvement but also contribute to the differential diagnosis between hemangiomas and vascular malformations.

Electrophysiological examination and high frequency ultrasonography for diagnosis of radial nerve torsion and compression

This study aims to evaluate the value of electrophysiological examination and high frequency ultrasonography in the differential diagnosis of radial nerve torsion and radial nerve compression.Patients with radial nerve torsion (n = 14) and radial nerve compression (n = 14) were enrolled. The results of neurophysiological and high frequency ultrasonography were compared.Electrophysiological examination and high-frequency ultrasonography had a high diagnostic rate for both diseases with consistent results. Of the 28 patients, 23 were positive for electrophysiological examination, showing decreased amplitude and decreased conduction velocity of radial nerve; however, electrophysiological examination cannot distinguish torsion from compression. A total of 27 cases showed positive in ultrasound examinations among all 28 cases. On ultrasound images, the nerve was thinned at torsion site whereas thickened at the distal ends of torsion. The diameter and cross-sectional area of torsion or compression determined the nerve damage, and ultrasound could locate the nerve injury site and measure the length of the nerve.Electrophysiological examination and high-frequency ultrasonography can diagnose radial neuropathy, with electrophysiological examination reflecting the neurological function, and high-frequency ultrasound differentiating nerve torsion from compression.

Patterns of visual field changes in thyroid eye disease

This article provides a systematic description of visual field changes in thyroid eye disease-compressive optic neuropathy (TED-CON). A retrospective, non-comparative chart review of patients with TED-CON and documented Humphrey Visual Field 24-2 or 30-2 testing was conducted with IRB approval. Ninety-six visual fields in 68 patients were classified into 7 broad categories (superior, inferior, diffuse, temporal, nasal, central/paracentral, enlarged blind spot) and 17 mutually exclusive patterns from the Ocular Hypertension Treatment Study (OHTS) or "other." Fifty-three of 96 visual fields (55%) showed an inferior defect using the broad categories, with the remaining 6 categories ranging from 2% to 14%. The five most common OHTS patterns were other (28%), partial arcuate (28%), partial peripheral rim (9%), arcuate (8%) and altitudinal (7%). Further sub-classification showed a predominance of inferior visual field defects, ranging from 33% to 93% of each category. Of the 78 visual fields in these five categories combined, 52 (67%) were inferior defects. Inferior defect is the most typical TED-CON-associated visual field change. While the OHTS categories are geared toward classification of glaucomatous patterns, the overall predominance of inferior field defects in TED-CON was clearly demonstrated. These "other" visual field changes showing central inferior defect up to but not crossing the horizontal meridian and not contiguous from blind spot to nasal meridian should be designated as "TED-CON pattern." The high proportion of visual fields falling under the "other" category, however, does demonstrate the need for a more specific and tailored visual field classification system for TED-CON.

Suprascapular nerve entrapment caused by an intraosseous ganglion of the scapula: A case report

RATIONALE

Suprascapular nerve compression is a rare but important entity that is often missed in clinical practice. Nerve dysfunction caused by an intraosseous ganglion of the glenoid is extremely rare, to the best of our knowledge, only 1 case of suprascapular nerve entrapment due to an intraosseous ganglion cyst has been reported previously in the published literature.

PATIENT CONCERNS

We report a 61-year-old woman who had complained right shoulder pain that lasted over 3 years which was exacerbated by overhead activities.

DIAGNOSES

We diagnosed it as suprascapular nerve entrapment at the spinoglenoid notch caused by an intraosseous ganglion of the scapula.

INTERVENTIONS

Plain X-ray, computed tomography, magnetic resonance imaging (MRI), and electromyography (EMG) of the shoulder.

OUTCOMES

She undertook surgical excision with curettage of the cyst. The infraspinatus fossa dull pain subsided immediately after surgery. No recurrence of the cystic lesion was noted on follow-up plain radiograph and MRI performed 18 months postoperatively. Shoulder external rotation strength was graded as 5 of 5.

LESSIONS

Intraosseous ganglion of the glenoid can cause compression of the suprascapular nerve when the lesion is expanded toward the spinoglenoid notch. The EMG study confirmed compression of the suprascapular nerve. The patient showed clinical and radiologic improvement after surgical decompression with no recurrence.

The Role of Supinator in the Pathogenesis of Chronic Lateral Elbow Pain: A Biomechanical Study

The relative contributions of the forearm extensors to the tensile force at the lateral epicondyle were examined by implanting a force transducer in the common extensor tendon of four soft fixed cadaver elbows and sequentially stretching each muscle arising from the lateral epicondye. Extensor carpi radialis brevis and extensor digitorum communis produced the largest increases while the superficial head of supinator produced a moderate increase in tensile force in the common extensor tendon. Extensor carpi radialis longus and extensor carpi ulnaris had no significant effect.

Radial tunnel pressure was measured using a balloon catheter in a separate study of five cadaver elbows. Radial tunnel pressure increased on moving the wrist from neutral to a flexion–pronation position. This positional rise in pressure was reduced by supinator musculotendinous lengthening (77%) while lengthening of the extensor carpi radialis brevis and extensor digitorum communis had no effect.

This study demonstrates a biomechanical basis for the superficial head of supinator in the aetiology of both lateral epicondylitis and radial tunnel syndrome.

Chiropractic and rehabilitation management of a patient with extraforaminal entrapment of L4 nerve with balance problem

BACKGROUND

Disc herniation is one of the most common causes of low back pain with radicular pain. Among various types of disc herniation, the extraforaminal disc herniation is a rare cause of lumbar radiculopathy. The aim of presenting this case study is to demonstrate the benefits of Chiropractic care including spine and extremity manipulation and rehabilitation in the treatment of a rare case of extraforaminal L4 nerve entrapment causing severe L4 radiculopathy and chronic mild low back pain (LBP).

OBJECTIVE

The aim of presenting this case study is to demonstrate the benefits of Chiropractic care including spine and extremity manipulation and rehabilitation in treatment of rare case of extraforaminal L4 nerve entrapment which caused severe L4 radiculopathy and chronic mild low back pain (LBP).

METHOD

A 45-year old female patient arrived at the clinic with chronic mild low back pain and right buttock pain, all of which had presented for two years' duration. During the preceding month, the radicular pain initiated in medium to high intensity, radiating to her right leg following the L4 dermatomal pattern with a periodic tingling sensation in her right foot. A neuro exam demonstrated a proprioception deficit in her right leg. A Romberg test was positive. The patient was treated by low amplitude high velocity spinal and extremity manipulation for 10 consecutive sessions (2 weeks), followed by rehabilitation and exercise therapy including advanced myofascial release therapy for an additional 12 sessions (4 weeks).

RESULTS

After treatment, the patient reported a significant improvement in her low back pain and radiculopathy. In addition, she achieved some improvement in balance.

CONCLUSION

It seems that Chiropractic care and rehabilitation therapy may be a safe and effective modality in treatment of an L4 radiculopathy in a patient with an extraforaminal L4 nerve entrapment. Although it is rare, an L4 extraforaminal disc herniation should be considered as a possible cause of symptoms in patients with chronic mild low back pain and severe L4 radiculopathy.

The Spatial Relationship and Surface Projection of Canine Sciatic Nerve and Sacrotuberous Ligament: A Perineal Hernia Repair Perspective

Sciatic nerve entrapment can occur as post-operative complication of perineal hernia repair when sacrotuberous ligament is incorporated during hernia deficit closure. This results in sciatic sensory loss and paralysis of the hind leg. This study investigated the spatial relationship of sciatic nerve and sacrotuberous ligament and their surface topographic projection of 68 cadavers (29 Beagles and 39 Taiwanese mongrels) with various heights (25–56 cm). By gross dissection, the sacrotuberous ligament and sciatic nerve were exposed and their distance in between was measured along four parts (A, B, C, D) of sacrotuberous ligament. The present study revealed that the C was the section of sacrotuberous ligament where the sciatic nerve and the sacrotuberous ligament are closest to each other. Furthermore, a positive correlation was observed between C and height of the dogs. From the present study, we found that the C in smaller dogs has the shortest distance between the sciatic nerve and the sacrotuberous ligament, and thus the most vulnerable to sciatic nerve entrapment, and needs to be avoided or approached cautiously during perineal hernia repair.

Degenerative Pathways of Lumbar Motion Segments--A Comparison in Two Samples of Patients with Persistent Low Back Pain

Background

Magnetic resonance imaging (MRI) is used to identify spinal pathoanatomy in people with persistent low back pain. However, the clinical relevance of spinal degenerative MRI findings remains uncertain. Although multiple MRI findings are almost always present at the same time, research into the association with clinical outcomes (such as pain) has predominantly focused on individual MRI findings. This study aimed to: (i) investigate how multiple MRI lumbar spine findings cluster together within two different samples of patients with low back pain, (ii) classify these clusters into hypothetical pathways of degeneration based on scientific knowledge of disco-vertebral degeneration, and (iii) compare these clusters and degenerative pathways between samples.

Methods

We performed a secondary cross-sectional analysis on two dissimilar MRI samples collected in a hospital department: (1) data from the spinal MRI reports of 4,162 low back pain patients and (2) data from an MRI research protocol of 631 low back pain patients. Latent Class Analysis was used in both samples to cluster MRI findings from lumbar motion segments. Using content analysis, each cluster was then categorised into hypothetical pathways of degeneration.

Results

Six clusters of MRI findings were identified in each of the two samples. The content of the clusters in the two samples displayed some differences but had the same overall pattern of MRI findings. Although the hypothetical degenerative pathways identified in the two samples were not identical, the overall pattern of increasing degeneration within the pathways was the same.

Conclusions

It was expected that different clusters could emerge from different samples, however, when organised into hypothetical pathways of degeneration, the overall pattern of increasing degeneration was similar and biologically plausible. This evidence of reproducibility suggests that Latent Class Analysis may provide a new approach to investigating the relationship between MRI findings and clinically important characteristics such as pain and activity limitation.

Venous compression as a cause of trigeminal neuralgia

AIM

The study objective was to verify venous compression as a cause of trigeminal neuralgia (TN) and to define the optimal surgical tactics for TN patients.

MATERIAL AND METHODS

Four hundred twenty one patients were operated on for TN at the Neurosurgical Department of the City Hospital №2 from 1998 to 2015. Veins in the trigeminal nerve root entry zone, as a significant compression factor, were identified in 40 patients (9.5%). Intraoperative data, questionnaires, and self-assessment inventories were analyzed. Treatment outcomes were assessed using the Barrow Neurological Institute (BNI) scale.

RESULTS

Patients with venous compression were divided into two groups. Eleven (27.5%) patients in the first group had isolated venous compression. The feature of microvascular decompression (MVD) in these patients was identification of all veins, vein mobilization, and, if possible, vein coagulation and resection. Resection of the vein along its course is a basic procedure to avoid recurrent neuralgia. The second group included 29 (72.5%) patients with a combination of venous and arterial compression. In these patients, a vein acted as an "assisting" compression factor: the vein changed the course of a compressing artery or nerve and exerted an additional compression effect on the nerve. The surgical tactics involved exploration of the trigeminal nerve root entry zone, arterial loop mobilization, and placement of a Teflon protector; venous vessels were coagulated and resected. The MVD efficacy was as follows: in group 1, 10 patients had a BNI score I-III, and 1 patient had a BNI score IV; in group II, 25 patients had a BNI score I-III, and 4 patients had a BNI score IV.

CONCLUSION

Venous compression can play both independent and assisting roles in the TN genesis. When exploring the trigeminal nerve, examination of the proximal trigeminal nerve is of particular importance, with paying attention to veins that may be a compression factor. In the case of isolated venous compression, the MVD surgical technique has some peculiarities, in particular coagulation and resection of veins compressing the trigeminal nerve root entry zone.

Load Carriage-Related Paresthesias: Part 1: Rucksack Palsy and Digitalgia Paresthetica

This is the first of a two-part article discussing loadcarriage- related paresthesias, including brachial plexus lesions (rucksack palsy), digitalgia paresthetica, and meralgia paresthetica. Paresthesias are sensations of numbness, burning, and/or tingling, usually experienced as a result of nerve injury, compression, traction, or irritation. Rucksack palsy is a traction or compression injury to the brachial plexus, caused by the shoulder straps of the rucksack. The patient presents with paresthesia, paralysis, cramping with pain, and muscle weakness of the upper limb. Muscle-strength losses appear to be greater in those carrying heavier loads. Hypothetical risk factors for rucksack palsy include improper load distribution, longer carriage distances, and load weight. Nerve traction, compression, and symptoms may be reduced by use of a rucksack hip belt; wider, better-padded, and proper adjustment of the shoulder straps; reduction of weight in the rucksack; a more symmetric distribution of the load; and resistance training to improve the strength and hypertrophy of the shoulder muscles. Assessment and neck joint and nerve mobilization may relieve brachial plexus tension and reduce symptoms. Another load-carriage-related disorder is digitalgia paresthetica, likely caused by compression of the sensory digital nerves in the foot during load carriage. Patients have paresthesia in the toes. Although no studies have demonstrated effective prevention measures for digitalgia paresthetica, reducing loads and march distances may help by decreasing the forces and repetitive stress on the foot and lower leg. Specialty evaluations by a physical therapist, podiatrist, or other healthcare provider are important to rule out entrapment neuropathies such as tarsal tunnel syndrome. Part 2 of this article will discuss meralgia paresthetica.

Chronic Compression of the Dorsal Root Ganglion Enhances Mechanically Evoked Pain Behavior and the Activity of Cutaneous Nociceptors in Mice

Radicular pain in humans is usually caused by intraforaminal stenosis and other diseases affecting the spinal nerve, root, or dorsal root ganglion (DRG). Previous studies discovered that a chronic compression of the DRG (CCD) induced mechanical allodynia in rats and mice, with enhanced excitability of DRG neurons. We investigated whether CCD altered the pain-like behavior and also the responses of cutaneous nociceptors with unmyelinated axons (C-fibers) to a normally aversive punctate mechanical stimulus delivered to the hairy skin of the hind limb of the mouse. The incidence of a foot shaking evoked by indentation of the dorsum of foot with an aversive von Frey filament (tip diameter 200 μm, bending force 20 mN) was significantly higher in the foot ipsilateral to the CCD surgery as compared to the contralateral side on post-operative days 2 to 8. Mechanically-evoked action potentials were electrophysiologically recorded from the L3 DRG, in vivo, from cell bodies visually identified as expressing a transgenically labeled fluorescent marker (neurons expressing either the receptor MrgprA3 or MrgprD). After CCD, 26.7% of MrgprA3⁺ and 32.1% MrgprD⁺ neurons exhibited spontaneous activity (SA), while none of the unoperated control neurons had SA. MrgprA3⁺ and MrgprD⁺ neurons in the compressed DRG exhibited, in comparison with neurons from unoperated control mice, an increased response to the punctate mechanical stimuli for each force applied (6, 20, 40, and 80 mN). We conclude that CCD produced both a behavioral hyperalgesia and an enhanced response of cutaneous C-nociceptors to aversive punctate mechanical stimuli.

Ultrasound in dual nerve impairment after proximal radial nerve lesion

Introduction

Sonography in classical nerve entrapment syndromes is an established and validated method. In contrast, few publications highlight lesions of the radial nerve, particularly of the posterior interosseus nerve (PIN).

Method

Five patients with a radial nerve lesion were investigated by electromyography, nerve conduction velocity and ultrasound. Further normative values of 26 healthy subjects were evaluated.

Results

Four patients presented a clinical and electrophysiological proximal axonal radial nerve lesion and one patient showed a typical posterior interosseous nerve syndrome (PINS). The patient with PINS presented an enlargement of the PIN anterior to the supinator muscle. However four patients with proximal lesions showed an unexpected significant enlargement of the PIN within the supinator muscle.

Conclusion

High-resolution sonography is a feasible method to demonstrate the radial nerve including its distal branches. At least in axonal radial nerve lesions, sonography might reveal abnormalities far distant from a primary proximal lesion site clearly distinct from the appearance in classical PINS.

[Ten cases report of vascular compressive syndrome caused by the facial, acoustic nerves]

OBJECTIVE

To search the features and the treatment of vascular compressive syndrome caused by the facial, acoustic nerves.

METHOD

Ten cases of vascular compressive syndrome caused by the facial, acoustic nerves were included in the group,which were treated by microvascular decompression(MVD). Besides, the microanatomic relationship between the nerve and their adjacent vessel at the root exit zone (REZ) were observed under microscope or nasoendoscopy in MVD.

RESULT

Tinnitus, vertigo and facial spasm disappeared after MVD in 7 cases (70%), improved in 2 cases (20%), and relapse in 1 case (10%). All cases were found out vessels compressing at the root zone of the facial nerve and the auditory nerve.

CONCLUSION

The Clinical features of vascular compressive syndrome caused by the facial, acoustic nerves are facial spasm, tinnitus, and vertigo, for which microvascular decompression has a positive therapeutic effect as long as the diagnosis is correct.

[Entrapment syndrome of posterior interosseous nerve caused by elbow cyst: 5 cases reports]

OBJECTIVE

To investigate the causes and operations for entrapment syndrome of posterior interosseous nerve caused by elbow cyst.

METHODS

Form March 2005 to March 2012,5 patients with entrapment syndrome of posterior interosseous nerve caused by elbow cyst were treated with surgical excision and neurolysis including 3 males and 2 females with an average age of 50.4 years old ranging from 35 to 60 years old. The course was from 3 to 10 months with an average of 6.3 months. The main clinical symptoms were pain on the outside of the forearm. The extension muscle power of the metacarpophalangeal joints at the fingers and the wrist had decreased. The EMC showed neurogenic damage or nerve conduction slowing down. According to the functional neurological evaluation standard of British Medical Research Institute ,the motion and sensory function after nerve injury was assessed.

RESULTS

Patients were followed up for 3 to 15 months with an average of 8.5 months. Wound healing in patients was good after the operations. There were no significant complications. Three patients were excellent (M4S3+) and 2 patients were good (M3S3). The hand joint function of 5 patients recovered well after operation.

CONCLUSION

The surgical excision and neurolysis for treatment of entrapment syndrome of posterior interosseous nerve caused by elbow ganglions cyst can remove the entrapment syndrome of the posterior interosseous nerve thoroughly ,promote the neurological function recovery. According to the functional evaluation standard ,operations achieved better therapeutic effect.

The roles of mechanical compression and chemical irritation in regulating spinal neuronal signaling in painful cervical nerve root injury

Both traumatic and slow-onset disc herniation can directly compress and/or chemically irritate cervical nerve roots, and both types of root injury elicit pain in animal models of radiculopathy. This study investigated the relative contributions of mechanical compression and chemical irritation of the nerve root to spinal regulation of neuronal activity using several outcomes. Modifications of two proteins known to regulate neurotransmission in the spinal cord, the neuropeptide calcitonin gene-related peptide (CGRP) and glutamate transporter 1 (GLT-1), were assessed in a rat model after painful cervical nerve root injuries using a mechanical compression, chemical irritation or their combination of injury. Only injuries with compression induced sustained behavioral hypersensitivity (p≤0.05) for two weeks and significant decreases (p<0.037) in CGRP and GLT-1 immunoreactivity to nearly half that of sham levels in the superficial dorsal horn. Because modification of spinal CGRP and GLT-1 is associated with enhanced excitatory signaling in the spinal cord, a second study evaluated the electrophysiological properties of neurons in the superficial and deeper dorsal horn at day 7 after a painful root compression. The evoked firing rate was significantly increased (p=0.045) after compression and only in the deeper lamina. The painful compression also induced a significant (p=0.002) shift in the percentage of neurons in the superficial lamina classified as low- threshold mechanoreceptive (sham 38%; compression 10%) to those classified as wide dynamic range neurons (sham 43%; compression 74%). Together, these studies highlight mechanical compression as a key modulator of spinal neuronal signaling in the context of radicular injury and pain.

Reappraising entrapment neuropathies--mechanisms, diagnosis and management

The diagnosis of entrapment neuropathies can be difficult because symptoms and signs often do not follow textbook descriptions and vary significantly between patients with the same diagnosis. Signs and symptoms which spread outside of the innervation territory of the affected nerve or nerve root are common. This Masterclass provides insight into relevant mechanisms that may account for this extraterritorial spread in patients with entrapment neuropathies, with an emphasis on neuroinflammation at the level of the dorsal root ganglia and spinal cord, as well as changes in subcortical and cortical regions. Furthermore, we describe how clinical tests and technical investigations may identify these mechanisms if interpreted in the context of gain or loss of function. The management of neuropathies also remains challenging. Common treatment strategies such as joint mobilisation, neurodynamic exercises, education, and medications are discussed in terms of their potential to influence certain mechanisms at the site of nerve injury or in the central nervous system. The mechanism-oriented approach for this Masterclass seems warranted given the limitations in the current evidence for the diagnosis and management of entrapment neuropathies.

Nerve physiology: mechanisms of injury and recovery

Peripheral nerve injuries are common conditions, with broad-ranging groups of symptoms depending on the severity and nerves involved. Although much knowledge exists on the mechanisms of injury and regeneration, reliable treatments that ensure full functional recovery are scarce. This review aims to summarize various ways these injuries are classified in light of decades of research on peripheral nerve injury and regeneration.

Pelvic plexus compression due to a uterine leiomyoma in a woman with acute urinary retention: a new hypothesis

Acute urinary retention (AUR) in women is an uncommon occurrence described by the International Continence Society (ICS) as a painful, palpable, or perceptible bladder when the patient is unable to pass urine. Contrarily to men, AUR in women is not usually due to any obstructive process. Neurologic causes are the most common reason for AUR in reproductive-age women. A few case reports have been published concerning women suffering from gynecological pathology and AUR, and they propose extrinsic compression of the urinary tract. In the case we report, AUR pathophysiology was compression of the pelvic plexus by a giant uterine leiomyoma. An electromyogram displayed motor polyradiculopathy of S1 and S2 nerve roots, and the patient was unable to urinate due to an uncontractible bladder.

Nerve compression syndromes of the upper extremity: diagnosis, treatment, and rehabilitation

Nerve compression syndromes of the upper extremity, including carpal tunnel syndrome, cubital tunnel syndrome, posterior interosseous syndrome and radial tunnel syndrome, are common in the general population. Diagnosis is made based on patient complaint and history as well as specific exam and study findings. Treatment options include various operative and nonoperative modalities, both of which include aspects of hand therapy and rehabilitation.

Assessment of nerve conduction study to establish most common electrophysiological predictor of lumbosacral radiculopathy among radiologically diagnosed L5S1 neural foramina compression cases

Magnetic resonance imaging (MRI) and electromyography (EMG) are complimentary investigations in diagnosis of lumbosacral radiculopathy (LSR). With changing pattern of S1 electrodiagnosis by H-reflex study measures, electrophysiological studies were conducted to establish most common electrophysiological predictors of LSR in MRI diagnosed L5S1 neural foramina compression subjects. Fifty subjects, with definite L5S1 neural foramina compression underwent electrophysiological evaluation and the data was analyzed using established electrodiagnostic criteria. Reduced H/M ratio in combination with absent H response was evident in 74 nerves. H-reflex study was abnormal in 88% subjects. Study concluded that, H/M ratio if used with other H-reflex study variables may be most common predictor of LSR.

Botulinum toxin for meralgia paresthetica in type 2 diabetes

Botulinum toxin has been used for a variety of neuropathic conditions in diabetes mellitus. Meralgia paresthetica is a mononeuropathy of femoral nerve seen in diabetes and obesity with an unclear etiopathogenesis. We studied the role of botulinum toxin in resistant cases of meralgia paresthetica in type 2 diabetes.

Physical examination of upper extremity compressive neuropathies

A thorough history and physical examination are vital to the assessment of upper extremity compressive neuropathies. This article summarizes relevant anatomy and physical examination findings associated with upper extremity compressive neuropathies.

Punched nerve syndrome: ultrasonographic appearance of functional vascular nerve impairment

PURPOSE

The mechanical impact of a neighboring vessel on a "punched" nerve segment is thought to be one possible cause of compression neuropathy but has not been proven definitively. We report on 9 subjects with unclear clinical mononeuropathies in whom we could clearly define peripheral nerve impairment by such vessels on real-time high-resolution ultrasound (HRUS).

MATERIALS AND METHODS

Nine subjects with unclear mononeuropathy based on clinical neurological examination were referred to our department for HRUS assessment. The shape, inner and outer echotexture, size and diameter, and overall integrity of these nerves were assessed including an exact analysis of the surrounding soft tissues to search for potentially extraneural pathology. This included duplex imaging to identify even tiny atypical vascular structures.

RESULTS

In all patients duplex HRUS showed the pulsatile and "punching" character of the relevant vessels and the direct mechanical impact of these vessel. The involved nerve segments appeared enlarged with a hypoechoic change of echotexture including at least partial masking of their inner fascicular texture.

CONCLUSION

Although rare, a "punching" vessel can be the cause of a compression neuropathy. Therefore, duplex HRUS must be included in every HRUS examination of patients with otherwise unclear mononeuropathy.

Electrophysciological analysis of entrapment neuropathies developed in acute and subacute period in paretic and non-paretic extremities in patients with stroke

OBJECTIVE

To investigate entrapment neuropathies in stroke patients in a hospital in Turkey with Medical Research Council (MRC) score < or = 2/5 and in those with MRC score > or = 3/5.

METHODS

The study comprising 40 patients from January 2008 to June 2009 in the Stroke Unit of the Department of Neurology, Yuzuncu Yil University in Van, Turkey, entailed electrophysiological analysis of median, ulnar, radial nerves, peroneal, tibial and sural nerves in paretic and nonparetic upper and lower extremities. National Institute of Health Stroke scale was used for the evaluation of neurological deficient, while nerve conduction studies were performed for the diagnosis of entrapment neuropathies (EN). The patients were divided into two groups based on their initial Medical Research Council (MRC) score: < 2/5 and > 3/5. Both groups had 20 patients each. The readings were compared in the control phase 45 to 50 days after the stroke. Paired samples test and t-test using SPSS version 15 were used for statistical analysis.

RESULTS

Carpal tunnel syndrome (CTS) at wrist was found in 7 (35%) patients, cubital tunnel syndrome at elbow in 3 (15%) patients, and evident reduction in motor action potential values of peroneal, median and ulnar nerve in 10 (50%) patients in the control studies for conduction on our patients with Medical Research Council (MRC) score of < or = 2/5, unlike the initial findings, in the paretic side. Among the patients, in the other group, 2 (10%) developed bilateral Carpel tunnel syndrome, and it was also detected in the healthy upper extremities in 2 (10%) more patients. In the control studies for conduction in patients with Medical Research Council score of 3/5, Carpel tunnel syndrome was detected in the healthy side in 4 (20%) patients and in the affected side in 3 (15%) patients.

CONCLUSION

In patients with severe paresis, if the affected extremity is not functional, symptoms of entrapment neuropathy are easy to occur.

[Pseudoexfoliation syndrome: pathogenesis of impairment of vegetative sympathetic innervation associated with cervical spine disorder]

The results of magnetic resonance imaging of the cervical spine in 33 patients with mono- and bilateral pseudoexfoliation syndrome (PES) and cervical osteochondrosis are presented. The protrusion of intervertebral discs localized in the site of ciliospinal center and rarer in the site of superior cervical sympathetic ganglion is found. The protrusion of intervertebral discs in patients with PES was associated with compression of spinal roots significantly more often than in patients with cataract and osteochondrosis but without PES (control group). The side of protrusion and compression of spinal roots corresponded to the side of PES in more than 50% of cases. Compressive disorders of cervical spinal structures may be of considerable importance in pathogenesis of PES.

Fear of movement/(re)injury and activity avoidance in persons with neurogenic versus vascular claudication

BACKGROUND CONTEXT

Activity avoidance and fear of movement/(re)injury are increasingly being recognized as important factors in the rehabilitation of persons suffering from chronic low back pain, yet these factors have not been thoroughly explored in persons suffering from neurogenic claudication resulting from lumbar spinal stenosis.

PURPOSE

To determine, compare, and explain differences in the degree of fear of movement/(re)injury and activity avoidance in persons with neurogenic claudication, vascular claudication, and asymptomatic volunteers.

STUDY DESIGN

Prospective controlled cohort study at an academic medical center.

PATIENT SAMPLE

Eighty-two adults aged between 55 and 90 years with neurogenic claudication, vascular claudication, or no back and leg symptoms.

METHODS

Subjects completed a visual analog scale for pain, the Center for Epidemiological Studies Depression Scale, the Quebec Back Pain Disability Scale, Short Form 36 (SF-36), and the 13-item version of the Tampa Scale for Kinesiophobia (Tampa). They were also asked to estimate their maximum walking distance.

OUTCOME MEASURES

The difference in the level of fear of movement/(re)injury and activity avoidance in the two symptomatic populations, as well as the predictive validity of self-reported measures such as pain level, functional impairment, and depression in determining fear avoidance.

RESULTS

The total Tampa score was significantly higher in individuals with neurogenic claudication (M=31.68; standard deviation [SD]=7.56; N=39) than vascular claudication (M=24.07; SD=6.57; N=15) (p=.002), whereas both symptomatic groups were significantly different from controls (M=18.71; SD=6.3; N=28) (p<.001 vs. neurogenic; p<.05 vs. vascular). Tampa scores were strongly correlated to the Center for Epidemiological Studies Depression Scale score (r=0.515; p<.001), SF-36 Physical Functioning score (r=-0.632; p<.001), and the visual analog scale average level of pain in a week (r=0.461; p<.001). Using a standard multiple regression model (R²=0.406; F(3,62)=13.47; p<.001), the amount of functional impairment, that is, the SF-36 Physical Functioning score, was the strongest contributor to the variance in the Tampa total score (β=-0.371; p=.014). The average level of pain did not make a significant or unique contribution in predicting the Tampa total score. Functional impairment as measured by the SF-36 Physical Functioning was strongly correlated with both pain (r=-0.740; p<.001) and depression (r=-0.488; p<.001).

CONCLUSIONS

Persons with neurogenic claudication have important elevations in fear and avoidance, higher than those with claudication from another source (vascular insufficiency). The impact of fear and avoidance along with other factors such as depression on pain, disability, and quality of life for persons with claudication and spinal stenosis need to be explored.

Modulation of sensitized C-fibers by adrenergic stimulation in human neuropathic pain

The chronic constriction injury model is widely used in studying mechanisms of neuropathic pain. In this model neuropathic pain can be influenced by sympathetic interventions. It is assumed that similar mechanisms as in animals are responsible for pain arising from nerve entrapment syndromes in humans. The aim of the present study was to investigate if in patients with nerve entrapment nociceptive afferents can be modulated by adrenergic stimulation.

METHODS

Twenty patients with pain due to a unilateral entrapment of the median nerve and 10 controls were included in the study. Spontaneous pain, mechanical and thermal evoked pain were assessed within the innervation territory of the lesioned nerve and the corresponding contralateral segment in patients and on the right hand side in healthy volunteers. The examinations were performed at baseline, during whole body cooling (sympathetic activation) and whole body warming (sympathetic inhibition), and after norepinephrine iontophoresis.

RESULTS

All patients reported spontaneous pain. Mechanical allodynia, punctate hyperalgesia and cold allodynia was not found. According to side-to-side differences in heat pain thresholds, patients were separated in patients with (n=10) and without (n=10) heat hyperalgesia. Adrenergic stimulation did not induce or enhance spontaneous or mechanical evoked pain in any patient or control subject. However in patients with pre-existing heat hyperalgesia sympathetic stimulation aggravated heat hyperalgesia significantly. Further in these patients the decrease in heat pain thresholds observed after norepinephrine iontophoresis was significantly higher compared to patients without pre-existing heat hyperalgesia.

CONCLUSION

Sympathetic-afferent interaction does not play a major role in pain generation due to nerve entrapment. Nevertheless in a subgroup of patients nociceptive afferents show sensitivity to physiological and pharmacological sympathetic stimulation. This finding is important because it emphasises that despite there is no clinical detectable effect on pain sympathetic afferent interaction can be found.

Trigeminal nerve: MRI anatomy and case presentation of trigeminal neuralgia due to arterial compression

Trigeminal neuralgia (TN), also known as tic douloureux is a chronic neuropathic pain disorder characterized by sporadic episodes of extreme, sudden burning or shock-like face pain that last from a few seconds to 2 minutes. Trigeminal neuralgia has a reported incidence of 5.9/100,000 women and 3.4/100,000 men in USA. The exact pathophysiology is still unclear, but demyelization leading to abnormal discharge in fibers of the trigeminal nerve is a probable cause. In the majority of cases, no structural lesion is detected but in almost 15% of patients medical imaging methods like MRI, CT or angiography can identify a vein or artery that compresses the nerve which results in focal demyelization. The authors present a case of trigeminal neuralgia investigated by MRI, which identified a vascular compression of the nerve 9 mm after emerging the pons by the superior cerebellar artery (SCA) and one of its branches. The authors also realize a review of the MRI anatomy of the trigeminal nerve.

Humeral septal aperture associated with supracondylar process: a case report and review of the literature

The supracondylar process is usually a beak-like osseous prominence located at the anteromedial aspect of the distal portion of the humerus. It is usually asymptomatic but occasionally may compress underlying structures such as the median or ulnar nerve, the brachial artery or its branches. The term septal aperture defines an oval or round shaped bony defect of the septum that separates the olecranon from the coronoid fossa of the humerus. It is of significance for surgeons because it may alter the fracture pattern at the region and thus their management. We present a rare case of coexistence of supracondylar process and septal aperture in a macerated left humerus. The reported incidence of the supracondylar process alone varies from 0.28% to 2.78%, while that of the septal aperture from 6.9% to 60%. We have reviewed the literature and emphasized the radiological and surgical significance of the findings.

Recurrent isolated abducens nerve paresis associated with persistent trigeminal artery variant

We report a 74-year-old woman who presented with recurrent isolated abducens nerve paresis. Cranial magnetic resonance imaging revealed that the right abducens nerve was sandwiched between the right internal carotid artery and a persistent trigeminal artery (PTA) variant, which might have led to neurovascular compression of the abducens nerve, resulting in abducens nerve damage. Normal variants of PTA, which are cerebellar arteries originating from a precavernous portion of the internal carotid artery, must be carefully observed as such variants can potentially cause a neurovascular compression of the abducens nerve.

[The lumbar disc herniation - management, clinical aspects and current recommendations]

Lumbar disc herniation has a high prevalence and strong social-medical impact. Patients suffer from lower back pain that radiates from the spine. Loss of sensation or paresis adds to the clinical picture. The diagnosis should be confirmed by imaging in patients considered for surgery. High remission rates initially warrant conservative treatment (adequate analgesia and physiotherapy) in many patients. If this treatment does not lead to significant alleviation within 5-8 weeks, surgery should be performed to reduce the risk of chronic nerve affection. Posterior interlaminar fenestration is the intervention primarily conducted for this diagnosis. A relapse in the same region occurs in up to 10% of patients after months through years, which sometimes necessitates a reoperation if symptoms are pertinent.

Anterior interosseous nerve compression syndrome: is there a role for endoscopy?

BACKGROUND

Anterior interosseous nerve syndrome is characterized by paralysis of the flexor digitorum profundus, the flexor pollicis longus and the pronator quadratus muscles without sensory loss. Extended exploration of the anterior interosseous nerve is the surgical treatment of choice. The present study evaluates the feasibility of an endoscopic approach for nerve decompression.

METHODS

Preparation of the anterior interosseous nerve was performed in ten human cadaver arms. Subsequently, one female patient suffering from anterior interosseous nerve syndrome was endoscopically operated on.

FINDINGS

A skin incision of 3-4 cm in the proximal direction was made at the forearm, and the median nerve was visualized between the pronator teres muscle and the flexor digitorum superficialis. Subsequently, the anterior interosseus nerve branch was identified, followed distally and decompressed under endoscopic view. The procedure could be accomplished in all cases under endoscopic view. Due to the very steep surgical angle, a branch of the anterior interosseus nerve was injured in one cadaver case. In all other cases, no adverse effects were observed. In the clinical case, the anterior interosseus nerve was endoscopically identified and decompressed, but a skin incision of 5 cm was required.

CONCLUSIONS

The results demonstrate that an endoscopic decompression of the anterior interosseus nerve is possible. Several difficulties occurred: Due to the depth of the surgical approach, especially in case of bulky muscles and very small skin incisions, the view is limited, harboring a higher risk of nerve injury. With more experience and specially designed endoscopes, application of this technique in anterior interosseus nerve compression syndrome might become more feasible.