Median nerve entrapments in the forearm - a case report of rare anterior interosseous nerve syndrome.

Nowadays, median nerve entrapment is a frequent issue. Many physicians are familiar with the most common median entrapment, which is the carpal tunnel syndrome (CTS). By contrast, less frequent entrapments, historically called "pronator syndrome" are still misdiagnosed as overuse syndrome, flexor tendinitis or other conditions. This article is meant to introduce proximal median nerve entrapments, followed by a case report of the rarest example - anterior interosseous nerve syndrome (AIN syndrome).

Radius palmar plate removal without carpal tunnel release: Correlation between plate position and median nerve symptoms.

We aimed to report the clinical results of volar plate removal without carpal tunnel release in patients with late-onset median neuropathy and to evaluate the relationship between plate position and median nerve symptoms. Part I. Twelve consecutive patients with late-onset median neuropathy treated with volar plate removal without carpal tunnel release were enrolled for analysis. Pre- and post-operative Tinel sign, Phalen and Ten test, subjective rating of tingling sensation, Mayo wrist score and Disabilities of the Arm, Shoulder and Hand (DASH) score were collected. Part II. 232 consecutive patients underwent volar plating for distal radius fracture. The relationships between median nerve symptoms and volar plate prominence on the Soong classification, fracture classification, gender and age were investigated. All cases except one showed complete symptom resolution at final follow-up, with negative Tinel sign and Ten test score of 10/10. Tingling was rated 0 at final follow-up. Mean Mayo wrist and DASH scores improved to 86.7 and 23.1, respectively. The incidence of the median nerve symptoms in our cohort was 5.6%. Even though the odds ratio in Soong grade 2 was 4.0957 (95% CI, 0.93-16.9) compared to the combination of grades 0 and 1, no statistically significant relationship was found between the median nerve symptoms and volar plate prominence (p > 0.05). Plate removal without carpal tunnel release adequately relieved symptoms of late-onset median neuropathy after volar plating in patients with distal radius fracture. LEVEL OF EVIDENCE: IV; Therapeutic.

Adductor Branch of Terminal Divisions of the Ulnar Nerve Transfer to the Thenar Motor Branch in a High Median Nerve Palsy: A Case Report.

CASE: The author reports a 4-month-old high median nerve palsy in a 19-year-old man with right forearm fractures, stabilized with dynamic compression plates and screws. Surgical exploration revealed a large median nerve neuroma in the midarm that was excised, and the gap was bridged with sural nerve cable grafts. The extensor carpi radialis nerve was transferred to the anterior interosseous nerve in the forearm. The adductor branch of terminal divisions of the ulnar nerve was transferred to the thenar branch of the median nerve in the hand. CONCLUSIONS: The adductor branch of ulnar nerve transfer to the thenar motor branch in high median nerve palsy efficiently restored thumb opposition in 10 months of follow-up. In addition, the patient's grasp and pinch improved, preserving thumb adduction.

Lacertus syndrome: a ten year analysis of two hundred and seventy five minimally invasive surgical decompressions of median nerve entrapment at the elbow.

PURPOSE: This study aims to assess the clinical presentation and surgical outcomes of lacertus syndrome (LS) and concomitant median nerve entrapments. METHODS: A retrospective study of prospectively collected data was conducted on patients undergoing lacertus release (LR) from June 2012 to June 2021. Available DASH (Disability of the Arm Shoulder Hand questionnaire) scores and post-operative Visual Analogue Scale (VAS) of pain, numbness, subjective satisfaction with surgical outcome, and intra-operative return of strength were analyzed. RESULTS: Two-hundred-seventy-five surgical cases were identified of which 205 cases (74.5%) underwent isolated LR, and 69 cases (25.1%) concomitant lacertus and carpal tunnel release. The three most common presenting symptoms in LS patients were loss of hand strength (95.6%), loss of hand endurance/fatigue (73.3%), and forearm pain (35.4%). Numbness in the median nerve territory of the hand was found in all patients with combined LS and carpal tunnel syndrome. Quick-DASH significantly improved (pre-operative 34.4 (range 2.3-84.1) to post-operative 12.4 (range 0-62.5), p < 0.0001) as did work and activity DASH (p < 0.0001). The postoperative VAS scores were pain VAS 1.9 and numbness VAS 1.8. Eighty-eight percent of patients reported good/excellent satisfaction with the surgical outcome. Intra-operative return of strength was verified in 99.2% of cases. CONCLUSION: LS is a common median nerve compression syndrome typically presenting with loss of hand strength and hand endurance/fatigue. Minimally invasive LR immediately restores hand strength, significantly improves DASH scores, and yields positive outcomes regarding VAS pain, numbness, and subjective satisfaction with surgery in patients with proximal median nerve entrapment at a minimum six month follow-up.

Unusual Anatomic Location of the Median Nerve Within the Pronator Teres Muscle: A Case Report.

CASE: A 57-year-old man presented with pain and paresthesia in both hands and was diagnosed with pronator teres syndrome. Surgical decompression of the left elbow and forearm revealed the median nerve in an unusual anatomic location, specifically running within the pronator teres muscle. CONCLUSION: Anatomic anomalies of the pronator teres muscle and the path of the median nerve have been described. However, there are no reports of the median nerve entering and traveling within the pronator teres. Surgeons should be aware of this anomaly to avoid potential iatrogenic injury when performing an anterior surgical approach to the elbow and proximal forearm.

Median nerve entrapment syndrome in the elbow and proximal forearm. Anatomic causes and results for a 55-case surgical series at a mean 7years' follow-up.

BACKGROUND: Proximal median nerve (MN) neuropathy represents 1% of upper-limb compressive neuropathies. The literature reports two clinical presentations, depending on the location of the entrapment: pronator teres (PT), and anterior interosseous nerve (AIN) syndrome. HYPOTHESIS: There is no correlation between symptoms and location of proximal compressive structures on the MN trunk or AIN. PATIENTS AND METHODS: Clinical and paraclinical data from 55 surgical MN releases around the elbow and proximal forearm were analyzed retrospectively. Mean age at diagnosis was 56±15years. Preoperative sensory and motor deficit signs were present in 89% of cases. Reduced MN conduction velocity and/or neurogenic anomalies in the MN territory were present in 94% of cases. Intraoperative details of compressive structures were collected. Patients were followed up in consultation to assess progression of symptoms and deficits. RESULTS: Mean follow-up was 84±70months. Objective motor deficit signs persisted in 18 of the 35 patients (18 cases), and objective sensory signs in 19 cases. A compressive anatomical structure was systematically found. There were at least two MN entrapment sites in 13 cases (24%). No isolated AIN entrapment was found. There was a significant correlation between symptom duration and persistence of objective sensory signs (p=0.002). DISCUSSION: There was no correlation between entrapment site and clinical signs on examination. Surgery requires exploring all potential entrapment sites. Improvement may be incomplete in case of late treatment. LEVEL OF EVIDENCE: IV; retrospective study.

A Rare Case of Median Nerve Entrapment within the Bone After Surgical Treatment of a Pediatric Supracondylar Humerus Fracture: A Case Report.

CASE: We present the rare event of median nerve bony entrapment after a supracondylar distal humerus fracture in a child. The median nerve was both clinically and electrically still, partially intact at 2 years after the injury. The nerve was surgically extracted from the bone. Follow-up evaluation a year later showed motor and sensory improvement. We found only 2 similar reports in the literature and one similar postmortem example. CONCLUSION: We hope that this case brings awareness of an unusual complication after a commonly encountered injury.

Surgical Excision of a Thrombosed Persistent Median Artery Causing Carpal Tunnel-Like Symptoms: A Case Report.

CASE: A 51-year-old man presented with pain and paresthesias in the median nerve distribution and a subjective loss of grip strength. Imaging revealed a thrombosed persistent median artery in the carpal tunnel abutting the median nerve. The thrombosed portion of the artery was surgically excised, and the patient experienced resolution of symptoms. CONCLUSION: Persistent median artery thrombosis is rare and can cause carpal tunnel syndrome. Ultrasound is a useful tool for diagnosis and appropriate surgical planning. Although treatment with systemic anticoagulation is an option, surgical excision resulted in resolution of symptoms and an excellent short-term outcome.

Proximal Median Nerve Compression: Pronator Syndrome.

Pronator syndrome (PS) is a compressive neuropathy of the median nerve in the proximal forearm, with symptoms that often overlap with carpal tunnel syndrome (CTS). Because electrodiagnostic studies are often negative in PS, making the correct diagnosis can be challenging. All patients should be initially managed with nonsurgical treatment, but surgical intervention has been shown to result in satisfactory outcomes. Several surgical techniques have been described, with most outcomes data based on retrospective case series. It is essential for clinicians to have a thorough understanding of median nerve anatomy, possible sites of compression, and characteristic clinical findings of PS to provide a reliable diagnosis and treat their patients.

Distal nerve transfer for thenar palsy: A cadaveric study.

INTRODUCTION: Severe proximal median nerve palsies often result in irreversible thenar atrophy and thumb abduction function loss. Tendon transfer involves substantial limitations and challenges; but, distal nerve transfer may provide an alternative treatment. Our goal was to validate the anatomical suitability of two distal ulnar nerve branches for thenar muscle reanimation. MATERIALS AND METHODS: We assessed nerve transfer to the recurrent branch of median nerve (RMN) in 16 embalmed cadaveric hands. The ulnar motor branch to the flexor digiti minimi brevis (FDMBn) and the ulnar motor branch to the third lumbrical (3rdLn) were assessed for transfer. Coaptation success was measured by the overlap of the nerve donor with the RMN and correspondence of nerve diameters. RESULTS: The mean transferable length and width of the RMN were 20.7 ± 4.5 and 1.0 ± 0.3 mm, respectively. We identified an average of three branches in the branching anatomy from the ulnar nerve to the hypothenar muscles. The maximal transferable lengths and widths of the FDMBn and the 3rdLn were 13.8 ± 4.4 and 0.5 ± 0.1 mm and 24.1 ± 6.4 and 0.4 ± 0.1 mm, respectively. The overlap with the RMN of the FDMBn and 3rdLn was 9.0 ± 3.6 (2.0-15.3) and 17.8 ± 6.0 (4.7-27.5) mm, respectively. CONCLUSIONS: This anatomical study demonstrates the feasibility of distal nerve transfers between the ulnar and median nerves in the hand for reanimation of thenar muscles. Ulnar motor donors of the BrFDMBn and 3rdLn likely represent the least morbid donors with short distances for regeneration and a single coaptation repair.

A case series of seven patients with recurrent median nerve neuropathy treated by the revision surgery of median nerve neurolysis and wrapping with radial artery perforator adipose flap.

Adhesion neuropathy of the median nerve with persistent pain can be a challenging problem. Currently, coverage of the median nerve with a well-vascularized soft tissue is deemed necessary after secondary neurolysis. Herein, we reviewed the outcomes of seven patients with a persistent median nerve neuropathy after a primary open carpal tunnel release or a median nerve repair, treated with neurolysis and median nerve wrapping with radial artery perforator adipose flaps. During the revision surgery, after a careful and complete neurolysis of the scarred median nerve, the distally based radial artery perforator adipose flap without its fascia was raised and rotated to wrap the median nerve. The mean size of the perforator flap was 1146 mm2, which was enough to wrap the median nerve in all patients. At 26 months postsurgery, both the visual analog scale score for pain with tingling, and the patient-reported outcome measures improved. There was no recurrence of the median nerve adhesion neuropathy and no major complications were noted. Tinel's sign at the palmar wrist completely disappeared in four patients and was relieved in three patients. The median distal motor latency becomes recordable, and closer to a normal compound motor action potential postoperatively in all patients. Secondary neurolysis and median nerve wrapping with a radial artery perforator adipose flap, which was modified to be softer and thinner than the radial artery perforator adipofascial flap, was a successful treatment for the recurrent median nerve neuropathy in terms of both pain relief and restoration of the hand function.

The Effectiveness of Ultrasonography in the Diagnosis of Spontaneous Hourglasslike Constriction of Peripheral Nerve in the Upper Extremity.

OBJECTIVE: To investigate the ultrasonographic characteristics in hourglasslike constriction of peripheral nerve in the upper extremity and to evaluate the value of ultrasonography in the diagnosis. METHODS: Nineteen patients with hourglasslike constriction of peripheral nerve in the upper extremity underwent ultrasonography and the results were compared with surgery. The ultrasonographic characteristics, the accurate rate, and the relation between the ultrasonography and surgery were analyzed. RESULTS: There were 22 affected nerves involved in 19 patients, including 17 radial neuropathies, 4 median neuropathies, and 1 musculocutaneous neuropathy. The accuracy rate of ultrasonography in diagnosing hourglasslike constriction of upper limb nerve was 87.93%. Ultrasonography showed that the constriction sites were completely consistent with the operation. The ultrasonography characteristics of hourglasslike constriction of upper limb nerves were hourglasslike nerve incompleteness or complete constriction, and the nerves at both ends were thickened, and no compression structure was seen around. All lesions with complete constriction diagnosed by ultrasonography were treated with resection of the lesion with or without graft. In addition, 71.43% with incomplete constriction were treated with neurolysis, and 28.57% with resection of the lesion with direct repair. CONCLUSIONS: Ultrasonography could be used as a routine noninvasive examination for hourglasslike constriction of upper limb nerves. Ultrasonography suggests that resection of the lesion rather than neurolysis should be considered in the treatment of complete constriction. For patients with clinical symptoms, ultrasonography showed local nerve enlargement but no constriction; clinicians should be prompted to explore carefully during operation to avoid missing nerve hourglasslike constriction.

Liberación endoscópica del nervio mediano en el tercio proximal del antebrazo. Nuevo abordaje / Endoscopic release of the median nerve in the proximal third of the forearm. A new approach

Introducción: El síndrome de pronador ha requerido clásicamente una cirugía abierta que deja gran cicatriz; técnicas endoscópicas iniciales requerían abordajes de 4cm en promedio y sin lograr una liberación de todas las estructuras. El propósito de este estudio es describir un nuevo abordaje endoscópico que permita descomprimir el nervio mediano de forma segura y completa con una cicatriz de menor tamaño y menos visible. Métodos: Descripción de una nueva técnica de descompresión del nervio mediano en el tercio proximal del antebrazo con incisión mínima y técnica endoscópica en especímenes cadavéricos criopreservados, describiendo incisión, anatomía endoscópica, corredores seguros y sitios de descompresión. Resultados: Se realizó en 20 codos de cadáveres abordaje endoscópico del nervio mediano en el antebrazo proximal con endoscopio de 4mm y 0° de angulación. Se presentan ventajas y limitaciones de la técnica y detalles quirúrgicos para la liberación en los puntos de compresión más comunes del nervio en el antebrazo. Realizamos en 3 pacientes esta técnica con buenos resultados y sin complicaciones. Discusión: Es posible la liberación del nervio mediano y la sección de estructuras aponeuróticas potenciales de compresión por endoscopia. La cabeza cubital del pronador y la arcada aponeurótica del flexor digitorum superficialis están implicados frecuentemente en el síndrome. La cicatriz es estéticamente buena. Es una técnica relativamente nueva, con menor morbilidad, que permite una recuperación más rápida de los pacientes. Conclusiones: Es posible realizar una descompresión completa del nervio mediano en el antebrazo con técnica endoscópica, segura y menor comorbilidad para el paciente

Introduction: Pronator syndrome has classically required open surgery that leaves a large scar; initial endoscopic techniques required approaches of an average 4cm without achieving release of all structures. The purpose of this study was to describe a new endoscopic approach that allows the median nerve to be safely and completely decompressed, leaving a smaller and less visible scar. Methods: Description of a new approach for decompression of the median nerve in the proximal third of the forearm with minimal incision and endoscopic technique in cryopreserved cadaveric specimens, describing incision, endoscopic anatomy, safe corridors and decompression sites. Results: In 20 elbows of cadavers, an endoscopic approach of the median nerve in the proximal forearm with a 4mm endoscope and 0° of angulation was performed. The advantages and limitations of the technique and surgical details are presented for release in the most common compression points of the nerve in the forearm. We performed this technique in 3 patients with good results without complications. Discussion: Release of the median nerve and section of potential aponeurotic compression structures by endoscopy is possible. The ulnar head of the pronator and the aponeurotic arch of the flexor digitorum superficialis are frequently implicated in the syndrome. The scar is aesthetically good. It is a relatively new technique, with lower morbidity that allows faster recovery of patients. Conclusions: It is possible to perform a complete decompression of the median nerve in the forearm using an endoscopic approach, safely with lower comorbidity for the patient

Endoscopic release of the median nerve in the proximal third of the forearm. A new approach. / Liberación endoscópica del nervio mediano en el tercio proximal del antebrazo. Nuevo abordaje.

INTRODUCTION: Pronator syndrome has classically required open surgery that leaves a large scar; initial endoscopic techniques required approaches of an average 4cm without achieving release of all structures. The purpose of this study was to describe a new endoscopic approach that allows the median nerve to be safely and completely decompressed, leaving a smaller and less visible scar. METHODS: Description of a new approach for decompression of the median nerve in the proximal third of the forearm with minimal incision and endoscopic technique in cryopreserved cadaveric specimens, describing incision, endoscopic anatomy, safe corridors and decompression sites. RESULTS: In 20 elbows of cadavers, an endoscopic approach of the median nerve in the proximal forearm with a 4mm endoscope and 0° of angulation was performed. The advantages and limitations of the technique and surgical details are presented for release in the most common compression points of the nerve in the forearm. We performed this technique in 3 patients with good results without complications. DISCUSSION: Release of the median nerve and section of potential aponeurotic compression structures by endoscopy is possible. The ulnar head of the pronator and the aponeurotic arch of the flexor digitorum superficialis are frequently implicated in the syndrome. The scar is aesthetically good. It is a relatively new technique, with lower morbidity that allows faster recovery of patients. CONCLUSIONS: It is possible to perform a complete decompression of the median nerve in the forearm using an endoscopic approach, safely with lower comorbidity for the patient.

Poly(ε-Caprolactone) Nanofiber Wrap Improves Nerve Regeneration and Functional Outcomes after Delayed Nerve Repair.

BACKGROUND: The purpose of this study was to assess the efficacy of biodegradable, electrospun poly(ε-caprolactone) nanofiber nerve conduits in improving nerve regeneration. METHODS: The authors used a rat forelimb chronic denervation model to assess the effects of poly(ε-caprolactone) conduits on improving nerve regeneration and upper extremity function. Three groups of rats were examined: (1) negative-control animals (n = 5), which underwent 8 weeks of median nerve chronic denervation injury followed by repair with no conduit; (2) experimental animals (n = 5), which underwent 8 weeks of median nerve chronic denervation followed by repair and poly(ε-caprolactone) nerve conduit wrapping of the nerve coaptation site; and (3) positive-control animals (n = 5), which were naive controls. All animals underwent compound muscle action potential and functional testing. At 14 weeks after repair, the median nerve and flexor muscles were harvested for histologic analysis. RESULTS: Histomorphometric analysis of regenerating median nerves demonstrated augmented axonal regeneration in experimental versus negative control animals (total axon count, 1769 ± 672 versus 1072 ± 123.80; p = 0.0468). With regard to functional recovery, experimental and negative-control animals (1.67 ± 0.04 versus 0.97 ± 0.39; p = 0.036) had regained 34.9 percent and 25.4 percent, respectively, of baseline hand grip strength at 14 weeks after repair. Lastly, less collagen deposition at the nerve coaptation site of experimental animals was found when compared to control animals (p < 0.05). CONCLUSION: Biodegradable, poly(ε-caprolactone) nanofiber nerve conduits can improve nerve regeneration and subsequent physiologic extremity function in the setting of delayed nerve repair by decreasing the scar burden at nerve coaptation sites.