Peripheral nerve stimulation (PNS): A valid and definitive therapeutical option for a case of anterior cutaneous nerve entrapment syndrome (ACNES).

Anterior cutaneous nerve entrapment syndrome (ACNES) is a cause of moderate to severe chronic pain, hyperesthesia/hypoesthesia, and altered perception of heat/cold in a specific region of the anterior abdominal wall, referable to the territory of innervation of one or more anterior branches of the intercostal nerves. None of the therapeutic options currently available has proved to be effective in the long term or decisive. In recent years, we have begun to treat purely sensory neuropathies, such as this, with the implantation of wireless peripheral nerve stimulators (PNS), achieving the safety of modular and personalized analgesia. We report the case of a 41-year-old man suffering from ACNES of the 8th intercostal nerve for two years. We first performed two consecutive ultrasound-guided diagnostic blocks of the anterior cutaneous branch of the 8th intercostal right nerve and then elected the patient for ultrasound-guided nerve decompression followed by neuromodulation and pulsed-radiofrequency (PRF). Taking into account full employment, young age, and the likelihood of having to repeat the treatment several times, we considered him for Peripheral Nerve Stimulation (PNS) implantation under ultrasound guidance, and we implanted the wireless lead at the anterior branch of the right 8th intercostal nerve, and programmed tonic stimulation 100 Hz PW 200 ms. The patient reported immediate pain relief and never took medication for this problem again, at two years follow-up. PNS has had an increasing role in the management of chronic neuropathic pain, especially in merely sensitive neuropathies like ACNES. We support future research on this theme.

Delayed vagal nerve compressive neuropathy following placement of vagal nerve stimulator: case report.

Vagal neuropathy causing vocal fold palsy is an uncommon complication of vagal nerve stimulator (VNS) placement. It may be associated with intraoperative nerve injury or with device stimulation. Here we present the first case of delayed, compressive vagal neuropathy associated with VNS coil placement which presented with progressive hoarseness and vocal cord paralysis. Coil removal and vagal neurolysis was performed to relieve the compression. Larger 3 mm VNS coils were placed for continuation of therapy. Coils with a larger inner diameter should be employed where possible to prevent this complication. The frequency of VNS-associated vagal nerve compression may warrant further investigation.

Middle cluneal nerve entrapment sites in the surgical field.

INTRODUCTION: Middle cluneal nerve (MCN) entrapment around the sacroiliac joint elicits low back pain (LBP). For surgical decompression to be successful, the course of the MCN must be known. We retrospectively studied the MCN course in 15 patients who had undergone MCN neurolysis. METHODS: Enrolled in this retrospective study were 15 patients (18 sides). We inspected their surgical records and videos to determine the course of the entrapped MCN. The area between the posterior superior- and the posterior inferior iliac spine was divided into areas A-D from the rostral side. The MCN transit points were identified at the midline and the lateral edge connecting the posterior superior- and posterior inferior iliac spine. Before and 6 months after surgery, the patients recorded the degree of LBP on the numerical rating scale and the Roland-Morris Disability Questionnaire. RESULTS: We decompressed 24 MCNs. The mean number was 1.3 nerves per patient (range 1-2). The MCN course was oblique in the cranio-caudal direction; the nerve tended to be observed in areas C and D. In six patients (40%), we detected two MCN branches, they were in the same area and adjacent. Postoperatively, LBP was improved significantly in all patients. CONCLUSION: Between the posterior superior- and the posterior inferior iliac spine, the MCN ran obliquely in the cranio-caudal direction; it was prominent in areas on the caudal side. In six (40%) patients, we decompressed two adjacent MCNs. Our findings are useful for MCN decompression surgery.

[Rare nerve compression neuropathies] / Seltene Nervenkompressionssyndrome.

UNCOMMON NERVE COMPRESSION SYNDROMES: In regard to the complex anatomical relationship of peripheral nerves and muscles, tendons, fasciae as well as their long course within those anatomical structures and additional close contact to bony structures, they are prone to suffer from local compression syndromes. Hence creating a vast majority of entrapment syndromes - well described in literature for almost every single nerve. The purpose of this article is to give an overview of symptoms, signs, diagnostic studies and treatment options, addressing especially the less known syndromes. Compression syndromes of the upper arm and shoulder region include the suprascapular nerve syndrome the compression of the axillary nerve within the spatium quadrilaterale and the compression of the long thoracic nerve at the chest wall. The upper extremity offers a variety of infrequent entrapment syndromes, as the pronator teres syndrome and anterior interosseus syndrome, both resulting from pressure to the median nerve in the forearm. Compression neuropathy in the course of the radial nerve in the distal upper extremity is also known as supinator syndrome. Guyon's canal syndrome is the ulnar side equivalent to the well-known carpal tunnel syndrome. In the case of a Cheiralgia paresthetica, a compression of a sensory branch of the superficial radial nerve can be seen. In the lower extremities, a variety of nerves especially in the groin and thigh area can be compressed as they pass through the narrow spaces between the abdominal muscles or underneath the inguinal ligament. Compression of the lateral femoral cutaneous nerve is the most common syndrome. Compression syndromes of the femoral and obturator nerves are most often iatrogenic. Pain around the knee, especially the lateral part and following orthopedic procedures of the knee, can arise from a compression or a lesion of a small infrapatellar branch of the saphenous nerve. Another probably underdiagnosed syndrome is piriformis syndrome, resulting from an entrapment of the sciatic nerve as it passes through certain muscular structures. In the distal lower extremity, the peroneal and tibial nerves can be compressed at multple sites, clinically known as peroneal nerve paralysis resulting from nerve compression around the fibular head, the anterior and posterior tarsal tunnel syndrome, and Morton's metatarsalgia.

[Rare Compression Syndrome of the Median Nerve due to a Supracondylar Humeral Process and a Ligament of Struthers]. / Seltenes Kompressionssyndrom des N. medianus durch den Processus supracondylaris und das Struthers-Ligament.

INTRODUCTION: A supracondylar process is a bony spur on the distal anteromedial surface of the humerus, and it is considered an anatomical variant with a prevalence of 0.4-2.7% according to anatomical studies. In almost all cases, it is associated with a fibrous, sometimes ossified ligament, which extends from the supracondylar process to the medial epicondyle. This ligament is known in the literature as the ligament of Struthers, named after the Scottish anatomist who first described it in detail in 1854. In rare cases, the supracondylar process can be a clinically relevant finding as a cause of nerve compression syndrome. The median and ulnar nerve can be trapped by the ring-shaped structure formed by the ligament of Struthers and the supracondylar process. CASE REPORT: A 59-year-old patient with symptoms of a cubital tunnel syndrome and additional ipsilateral sensory deficits in his thumb was referred to our clinic. Electroneurography showed no signs of an additional carpal tunnel syndrome. Preoperative x-ray and CT scans of the upper arm revealed a supracondylar process, which led us to suspect an associated entrapment of the median nerve. An MRI scan of the upper arm showed a ligament of Struthers and signs of a related median nerve compression as we initially assumed. We performed a surgical decompression of the median nerve in the distal upper arm and of the ulnar nerve in the cubital tunnel. Intraoperatively, there was evidence of compression of the median nerve due to the supracondylar process and the ligament of Struthers. The latter was cleaved and then resected along with the supracondylar process. Three months after surgery, the patient had no motor or sensory deficits. SUMMARY: The ring-shaped structure formed by the supracondylar process and ligament of Struthers represents a rare cause of compression syndrome of the median and ulnar nerve. Its incidence remains unknown so far. This anatomical variant should be considered a differential diagnosis in case of possibly related nerve entrapment symptoms after ruling out other, more frequent nerve compression causes. Moreover, the supracondylar process should be completely resected including the periosteum during surgery to minimise the risk of recurrence.

Identification and decompression of superior cluneal nerve implicated in low back pain.

INTRODUCTION: Low back pain (LBP) can be attributable to entrapment of the superior cluneal nerve (SCN) around the iliac crest. Surgical decompression is a useful treatment; however, finding all entrapped SCNs involved in patients with LBP can be difficult. We performed a retrospective study to help identify entrapped SCNs in the narrow surgical field. METHODS: We enrolled 20 LBP patient (22 sides) with SCN entrapment. They were 9 males and 11 females; their mean age was 72.5 years. We developed a 3-step procedure for successful SCN decompression surgery. In step 1, the thoracolumbar fascia is exposed and the SCN penetrating the fascia is released. In step 2, the fascia is opened and the SCN is released. In step 3, the fascia above the iliac crest is opened and the SCN is released. RESULTS: We successfully released 66 nerves; the average was 3.0 ± 0.8 (1-4) per patient. Step 1 detected 18 nerves (27.3%), step 2 identified 35 (53.0%), and in step 3, 13 (19.7%) were recognized. By tracing the thin nerves branching off the SCN, we found 7 nerves (10.6%). We performed 22 operations; step 1 identified 16 SCNs (72.7%), step 2 identified 21 (95.5%), and step 3 found 12 nerves (54.5%). CONCLUSIONS: The SCN is most readily identified upon opening of the thoracolumbar fascia. To identify as many SCN branches as possible, our 3-step method may be useful.

Lateral Femoral Cutaneous Nerve Cryoneurolysis for Meralgia Paresthetica: A Case Report.

Meralgia paresthetica (MP) is a disorder of lateral femoral cutaneous nerve mononeuropathy caused by entrapment or compression of the nerve. It is characterized by numbing, tingling, and burning pain in the lateral aspect of the thigh. The current treatments for MP include conventional medical management, peripheral nerve blocks, and surgical interventions. Some patients who suffer from MP can experience intractable pain and medical management of MP is often inadequate to provide satisfactory pain control. Although regional anesthesia provides excellent pain relief, the analgesic effects of peripheral nerve block are short-lived. Emerging evidence suggests that cryoneurolysis has a low-risk safety profile and can provide prolonged pain relief of superficial nerves when administered appropriately. We present a successful case of a patient with intractable neuropathic pain resulting from MP treated with cryoneurolysis therapy. The patient demonstrated immediate pain relief by 100% after the procedure followed by 80% and 60% pain reduction at 1-month and 3-months follow-up, respectively. Cryoneurolysis may be an alternative modality for patients who fail at conventional medical treatments of neuropathic pain.

Visceral symptoms in patients with anterior cutaneous nerve entrapment syndrome (ACNES): expression of viscerosomatic reflexes?

PURPOSE: Anterior cutaneous nerve entrapment (ACNES) is characterized by neuropathic pain in a predictable, circumscript abdominal area. The diagnostic delay is long, with half of ACNES-affected individuals reporting nausea, bloating, or loss of appetite mimicking visceral disease. The aim of this study was to describe these phenomena and to determine whether treatment could successfully reverse the visceral symptoms. METHODS: This prospective observational study was conducted between July 2017 and December 2020 at SolviMáx, Center of Excellence for Chronic Abdominal Wall and Groin Pain, Máxima Medical Center, Eindhoven. Adult patients who fulfilled published criteria for ACNES and reported at least one visceral symptom at intake were eligible for the study. A self-developed Visceral Complaints ACNES Score (VICAS) questionnaire that scores several visceral symptoms (minimum 1 point, maximum 9 points) was completed before and after therapy. The success of treatment was defined as at least 50% reduction in pain. RESULTS: Data from 100 selected patients (86 females) aged 39 ± 5 years were available for analysis. Frequently reported symptoms were abdominal bloating (78%), nausea (66%) and altered defecation (50%). Successful treatment significantly reduced the number of visceral symptoms, with a VICAS before of 3 (range 1-8) and after of 1 (range 0-6) (p < 0.001). A low baseline VICAS was associated with successful treatment outcome (OR 0.738, 95% CI 0.546-0.999). CONCLUSION: Patients with ACNES may report a variety of visceral symptoms. Successful treatment substantially reduces these visceral symptoms in selected patients.

A clinicopathological study of low back pain due to middle cluneal nerve entrapment: case series.

PURPOSE: The middle cluneal nerve (MCN) is a pure sensory nerve around the middle buttock. Its entrapment between the iliac crest and the long posterior sacroiliac ligament elicits low back pain (LBP) that can be treated by MCN neurolysis or neurectomy. Because few studies examined the pathology of MCN entrapment (MCN-E) we subjected 7 neurectomized specimens from 6 LBP patients to pathologic study. METHODS: We present 6 consecutive patients (7 sides) with intractable LBP who underwent successful MCN neurectomy. Their symptom duration ranged from 6 to 96 months (average 47.3 months); the follow-up period ranged from 6 to 17 months (average 11.7 months). The surgical outcomes were evaluated using the numerical rating scale (NRS) for LBP and the Roland-Morris Disability Questionnaire (RDQ) score. The resected MCNs underwent neuropathological analysis. RESULTS: Postoperatively, all 6 patients reported immediate LBP amelioration; their NRS and RDQ scores were improved significantly. Pathological study of the 7 resected nerves showed that the myelinated fiber density was decreased in 6 nerves; we observed marked enlargement (n = 5), perineurial thickening and disruption (n = 6), intrafascicular fibrous changes (n = 5), myelinated fibers separated by fibrous cells under the perineurium (n = 4), and Renaut bodies (n = 3). The 7th nerve appeared normal with respect to the density and size of the myelinated fibers, however, the perineurium was slightly thickened. CONCLUSION: We present pathological evidence at the MCN compression site of 7 nerves from 6 patients whose LBP was alleviated by MCN neurectomy, indicating that MCN entrapment can elicit LBP.

Pulsed radiofrequency or surgery for anterior cutaneous nerve entrapment syndrome: Long-term results of a randomized controlled trial.

PURPOSE: Patients with anterior cutaneous nerve entrapment syndrome (ACNES) often require a step-up treatment strategy including abdominal wall injections, pulsed radiofrequency (PRF) or a neurectomy. Long-term success rates of PRF and surgery are largely unknown. The aim of the current study was to report on the long-term efficacy of PRF and neurectomy in ACNES patients who earlier participated in the randomized controlled PULSE trial. METHODS: Patients who completed the PULSE trial were contacted about pain status and additional treatments in the following years. Treatment success was based on numerical rating scale (NRS) following IMMPACT recommendations and Patient Global Impression of Change (PGIC) scores. RESULTS: A total of 44 of the original 60 patients were eligible for analysis (73.3%). Median follow-up was 71.5 months. One patient (4.3%) was still free of pain after a single PRF session, and five additional patients (21.7%) were free of pain by repetitive PRF treatments. By contrast, 13 patients (61.9%) in the neurectomy group were still free of pain without additional treatments. All pain recurrences and therefore primary re-interventions occurred in the first 2 years after the initial treatment. CONCLUSION: Approximately one in five ACNES patients undergoing PRF treatment reports long-term success obviating the need of surgical intervention. Surgery for ACNES is long-term effective in approximately two of three operated patients. Recurrent ACNES beyond 2 years after either intervention is rare.

Pronator syndrome and anterior interosseous nerve palsy due to neurolymphomatosis: a case report.

Pronator syndrome is a median nerve entrapment neuropathy that can be difficult to diagnose due to its variable presentation and objective findings. Neurolymphomatosis is an uncommon disease in which malignant lymphocytes infiltrate central or peripheral nerve endoneurium and is often missed for prolonged periods prior to diagnosis. We present a rare case of pronator syndrome and anterior interosseous nerve palsy due to neurolymphomatosis that was occult on initial MRI in spite of the presence of a median nerve mass discovered intra-operatively during neurolysis. This case demonstrates the value of ultrasound for the examination of peripheral nerve pathology and illustrates its utility as an adjunct to MRI, in part due to the ability to screen a large region.

Median nerve entrapment during closed reduction of antebrachium fracture in a child.

This is a case report of a four-year-old boy who suffered a forearm fracture managed with closed reduction and casting for six weeks. Postoperatively, the patient showed symptoms of median nerve affection which was misinterpreted as neuropraxia. Ultrasonography of the forearm revealed that the median nerve was trapped in the radius fracture site. The patient underwent a second operation with neurolysis and nerve grafting. This case report highlights the use of ultrasonography in the diagnostics of nerve entrapment neuropathy.

Superior Cluneal Nerve Entrapment Syndrome: Thought to Be Spondylolysis.

A rare but typically overlooked diagnosis in the orthopaedic surgery community is superior cluneal nerve (SCN) entrapment syndrome. The cluneal nerves function as purely sensory fibers, and the SCNs provide cutaneous innervation to the posterior parasacral, gluteal, and posterolateral thigh regions. When irritated, this syndrome can cause acute and chronic lower back pain and lower extremity symptoms. A 14-year-old adolescent girl presented to the clinic for an evaluation of pain in the right side of her lower back. The patient's physical examination showed tenderness to palpation on the right posterior iliac crest seven centimeters from the midline. Her neurologic examination demonstrated normal deep tendon reflexes, muscle strength, and sensation in the L2-S1 dermatomal distribution. Although imaging showed evidence of a left L5 spondylolysis, she responded positively to a steroid injection over the posterior iliac crest but negatively to one over the L5 pars defect. She later underwent a right SCN decompression surgery. After the procedure, she reported at least 90% improvement in her pain and rated it as a one in severity, on a scale of 0 to 10. Research regarding SCN entrapment syndrome has increased in the past several years. However, most of these studies are limited to the adult population. Therefore, more reports highlighting the potential for this syndrome in adolescents are needed as well.

Meralgia Paresthetica: Relevance, Diagnosis, and Treatment.

BACKGROUND: Pain and sensory disturbance in the distribution of the lateral femoral cutaneous nerve in the ventrolateral portion of the thigh is called meralgia paresthetica (MP). The incidence of MP has risen along with the increasing prevalence of obesity and diabetes mellitus and was recently estimated at 32 new cases per 100 000 persons per year. In this review, we provide an overview of current standards and developments in the diagnosis and treatment of MP. METHODS: This review is based on publications retrieved by a selective literature search, with special attention to meta-analyses, systematic reviews, randomized and controlled trials (RCTs), and prospective observational studies. RESULTS: The diagnosis is mainly based on typical symptoms combined with a positive response to an infiltration procedure. In atypical cases, electrophysiological testing, neurosonography, and magnetic resonance imaging can be helpful in establishing the diagnosis. The literature search did not reveal any studies of high quality. Four prospective observational studies with small case numbers and partly inconsistent results are available. In a meta-analysis of 149 cases, pain relief was described after infiltration in 85% of cases and after surgery in 80%, with 1-38 months of follow-up. In another meta-analysis of 670 cases, there was pain relief after infiltration in 22% of cases, after surgical decompression in 63%, and after neurectomy in 85%. Hardly any data are available on more recent treatment options, such as radiofrequency therapy, spinal cord stimulation, or peripheral nerve stimulation. CONCLUSION: The state of the evidence is limited in both quantity and quality, corresponding to evidence level 2a for surgical and non-surgical methods. Advances in imaging and neurophysiological testing have made the diagnosis easier to establish. When intervention is needed, good success rates have been achieved with surgery (decompression, neurectomy), and variable success rates with infiltration.

Variations of the obturator nerve and implications in obturator nerve entrapment treatment: an anatomical study.

INTRODUCTION: Obturator nerve entrapment or idiopathic obturator neuralgia is an unfamiliar pathology for many physicians which can lead to diagnostic errancy. This study aims to identify the potential compression areas of the obturator nerve to improve therapeutic management. MATERIAL AND METHODS: 18 anatomical dissections of lower limbs from 9 anatomical cadavers were performed. Endopelvic and exopelvic surgical approaches were utilized to study the anatomical variations of the nerve and to identify areas of entrapment. RESULTS: On 7 limbs, the posterior branch of the obturator nerve passed through the external obturator muscle. A fascia between the adductor brevis and longus muscles was present in 9 of the 18 limbs. The anterior branch of the obturator nerve was highly adherent to the fascia in 6 cases. In 3 limbs, the medial femoral circumflex artery was in close connection with the posterior branch of the nerve. CONCLUSION: Idiopathic obturator neuropathy remains a difficult diagnosis. Our cadaveric study did not allow us to formally identify one or more potential anatomical entrapment zones. However, it allowed the identification of zones at risk. A clinical study with staged analgesic blocks would be necessary to identify an anatomical area of compression and would allow targeted surgical neurolysis.

Suprascapular nerve entrapment caused by a large hematoma of the scapula: a case report.

BACKGROUND: Suprascapular nerve entrapment is a rare disorder that is frequently misdiagnosed as another disease. The suprascapular nerve is commonly entrapped at the following two sites: the suprascapular and spinoglenoid notches. Nerve entrapment at the spinoglenoid notch causes infraspinatus muscle weakness and atrophy. Patients present with posterior shoulder pain and weakness. Magnetic resonance imaging is used to confirm the diagnosis of a spinoglenoid cyst and nerve compression. Open or arthroscopic aspiration or decompression is indicated for patients with cysts in whom conservative treatment has failed and those with cysts associated with suprascapular nerve compression. CASE PRESENTATION: Herein, we describe the case of a 49-year-old man with suprascapular nerve entrapment caused by a large cyst, namely, a hematoma, in the superior scapular and spinoglenoid notches. Open surgical decompression of the suprascapular nerve was performed owing to an intact rotator cuff and glenoid labrum. CONCLUSION: Posterior shoulder pain promptly resolved without complications.

Long-term outcome after surgery for middle cluneal nerve entrapment neuropathy.

PURPOSE: Entrapment of the middle cluneal nerve (MCN-E) can elicit low back pain (LBP). Patients whose LBP responds only transiently to the analgesic effects of MCN blockage may be candidates for surgery. This study addresses its long-term efficacy. METHODS: We initially subjected 34 MCN-E patients (48 sides) to surgical release. Of these, 4 were excluded from this study because their follow-up was shorter than 24 months. The mean age of the 30 included patients was 71.5 years; the mean postoperative follow-up period was 40.4 months. Clinical outcomes were assessed on the Numerical Rating Scale (NRS) for LBP and the Roland Morris Disability Questionnaire (RDQ) before surgery and at the latest follow-up visit. RESULTS: The 30 patients (44 sides) reported severe LBP, leg symptoms were elicited by 32 sides. A mean of 1.4 MCN branches were surgically released, 32 sides were addressed by neurolysis, 7 by neurectomy, and 5 underwent both procedures due to the presence of 2 nerve branches. There were no complications. In the course of a mean follow-up of 26.3 months, MCN-E elicited recurrent symptoms on 6 sides; all had undergone neurolysis or neurectomy and a second operation improved the symptoms. All patients showed significant improvement at the last follow-up visit. Postoperatively both their NRS for LBP and their RDQ scores were improved (pre- vs. postoperative scores, p < 0.05). CONCLUSIONS: While surgical release of MCN-E is expected to yield long-term symptom relief, on 6 of 32 sides (18.8%) treated by neurolysis the patients reported pain recurrence. Whether neurectomy effectively prevents the recurrence of MCN-E in the long term requires further study.