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.

Ultrasound-Guided Perineural Injection for Pronator Syndrome Caused by Median Nerve Entrapment.

Patients and physicians have increasingly sought minimally invasive procedures such as ultrasound-guided injection for the treatment of peripheral nerve entrapment syndromes. In this series, we assessed subjective outcome data in 14 patients who underwent ultrasound-guided perineural hydrodissection and steroid injection for pronator syndrome secondary to median nerve entrapment in the pronator tunnel. Excellent symptomatic relief (≥75% improvement) was achieved in 70% of nerves with 3-month follow-up data, with no significant change in symptoms between 3 and 6 months. These outcomes suggest that this technique could play a role in the management of pronator syndrome due to median nerve entrapment.

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.

Clinical, Radiological, and Electrodiagnostic Diagnosis of Pronator Syndrome Concurrent With Carpal Tunnel Syndrome.

PURPOSE: This is a retrospective observational study that assessed the prevalence of positive diagnostic imaging and electrodiagnostic (EDX) findings in patients diagnosed with pronator syndrome (PS), who previously had a carpal tunnel syndrome (CTS) surgery. The other purpose of our study was to determine how often PS occurred and was missed in patients treated surgically for CTS. METHODS: The files of 180 patients who underwent CTS surgery were reviewed retrospectively. We assessed all patients for a diagnosis of PS. We accepted the clinical findings and patient history as the reference standard for the diagnosis of PS. Anteroposterior and lateral radiographs of the elbow, bilateral upper limb magnetic resonance imaging (MRI) studies, and bilateral dynamic forearm ultrasound (US) were performed on patients with clinical symptoms and physical examinations that indicated PS. Bilateral upper limb EDX was also performed for these patients. One patient refused additional tests. RESULTS: A total of 174 extremities in 146 patients were included in the study. Pronator syndrome was diagnosed by 2 hand surgeons in 22 extremities (19 patients) through a clinical evaluation that included a history and physical examination. Diagnostic testing was positive for findings of PS in 24% of extremities (5 of 21) tested by EDX, in 57% of extremities (12 of 21) tested by US, and 5% of extremities (1 of 21) tested by MRI. There was no lower humeral spur that could cause median nerve compression on any plain radiographs. CONCLUSIONS: With clinical evaluation as the reference standard, EDX, US, and MRI are not helpful in making a diagnosis of PS concurrent with CTS. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

Mixed neuropathy presenting clinically as an anterior interosseous nerve palsy following shoulder arthroscopy: a report of four cases.

BACKGROUND: Anterior interosseous nerve (AIN) palsies can arise spontaneously or be attributed to one of many causes. We present 4 cases, the largest series to date, in which a mixed peripheral neuropathy presented primarily as an AIN palsy following ipsilateral shoulder arthroscopy. In this report, we detail the patient's presenting symptoms, describe our management of the complication, and provide hypotheses for the mechanism behind the complication. METHODS: Four different surgeons performed the initial arthroscopic surgeries, but the senior author in all cases managed follow-up and treatment of the neuropathy. All patients were informed and agreed to have their cases published. RESULTS: All four patients experienced significant recovery, although 2 of 4 required AIN decompression and exploration because of failure to improve with conservative management. CONCLUSION: Whereas variables such as position, index surgical procedure, and use of regional anesthesia varied among our patients, the one constant was the fluid extravasation from the arthroscopy itself, and for this reason we believe that if there is one singular cause to explain all of these neuropathies, it would be increased pressure in the upper arm and forearm from fluid extravasation in patients with at-risk anatomy. Outside of prevention, recognizing this complication and providing appropriate intervention or referral to a surgeon capable of appropriate intervention are important for any surgeon performing shoulder arthroscopies.

Effect of pronator teres muscle botulinum neurotoxin type-A injection on proximal median nerve entrapment.

PURPOSE: We aimed to evaluate the effect of botulinum neurotoxin type-A (Btx-A) injection into the pronator teres muscle in proximal median nerve entrapment (PMNE). METHODS: Intramuscular injection of 30 IU Btx-A into the pronator teres muscle was performed in 12 patients (14 extremities) diagnosed with PMNE. The injection was made under nerve stimulator control. One patient with thoracic outlet syndrome was excluded from the study and not included in the clinical evaluation. Grip and pinch strength, 2-point discrimination, Q-DASH score, and pain on VAS were evaluated and compared before and 6-8 months after injection. The patients were contacted again by phone after the first and fifth years and asked about PMNE symptomatology. RESULTS: None of the patients had complications. No significant difference in pinch strength was observed following Btx-A injection, but there was significant improvement in grip strength, 2-point discrimination, and Q-DASH and VAS pain scores. CONCLUSION: The outcomes of our study were promising: Btx-A injection improved symptoms in patients with PMNE. LEVEL OF EVIDENCE: Level IV.

A Rare Case of Traumatic Acute Pronator Syndrome in the Setting of Anticoagulation Therapy.

Pronator syndrome (PS) is a rare type of peripheral compression neuropathy in which the median nerve becomes entrapped as it passes through the pronator teres muscle at the proximal forearm. We report an unusual case of acute PS in a 78-year-old patient on warfarin who presented after traumatic forearm injury with forearm swelling, pain, and paresthesias. After emergent nerve decompression and hematoma evacuation, the patient regained near complete recovery of median nerve function six months after diagnosis and treatment.

Lacertus Syndrome: an Outcome Analysis After Lacertus Release.

Purpose: The lacertus fibrosus or bicipital aponeurosis is a sheet of ligamentous tissue just distal to the elbow joint and can be a compression point for the median nerve. Essentially, lacertus syndrome is a subset of pronator syndrome and an uncommon diagnosis by itself. Surgical release of the lacertus consists of a small 2-cm incision that can be performed under local anesthesia. This study aimed to evaluate the outcome of lacertus release in resolving median nerve symptoms. Methods: This retrospective study was performed at Prince Court Medical Centre, Kuala Lumpur, Malaysia, from January 2020 until June 2021. Ninety-three patients who presented with numbness of fingers, hand, or upper limb; forearm pain; and muscle weakness. They were diagnosed with lacertus syndrome on the basis of local tenderness at the lacertus fibrosus with either weakness of flexor pollicis longus and flexor digitorum profundus of the index finger or paresthesia over the thenar eminence. The patients underwent 3 months of hand therapy, and those with no symptom improvement were offered lacertus release performed by a single surgeon. The surgical technique consists of a surgical incision starting from a point 2 cm distally and 2 cm radially to the medial epicondyle. The incision projects 2 cm distally in an oblique fashion toward the radial styloid. A wide-awake local anesthesia no tourniquet (WALANT) technqiue was utilized and 20 mL of local anesthesic was injected subcutaneously around this region at least 20 minutes before the surgery. Careful dissection was made subcutaneously, and the lacertus fibrosus was identified as a thickened, shiny white structure and released. The Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, grip strength, and pinch strength were tested before and after surgery. At 6 months after surgery, the QuickDASH score was again assessed with a WALANT satisfactory questionnaire. Results: A total of 93 patients were included in the study. The mean age of the patients was 38.7 years, and most were women (77.4%). The mean operating time was 70 minutes. The mean preoperative QuickDASH score was 53, which significantly reduced immediately after surgery to 7.8 (P < .001) and remained low at 6 months after surgery (10.6). The mean grip strength showed a significant increase from a preoperative mean of 16 kg to a postoperative mean of 24 kg (P < .001). Pinch strength also significantly increased from a preoperative mean of 9 kg to 13 kg after surgery (P < .001). Conclusions: Lacertus syndrome remains an underdiagnosed disease that can be treated efficiently with a directed minimal surgical incision under wide-awake local anesthesia. Lacertus release appears to significantly reduce pain and numbness with markedly improved hand grip and pinch strength. The corresponding QuickDASH scores also improved significantly after surgery. This study is vital to our understanding of proximal median nerve entrapment and to accurately diagnose it. Type of study/level of evidence: Therapeutic III.

How to Differentiate Pronator Syndrome from Carpal Tunnel Syndrome: A Comprehensive Clinical Comparison.

The diagnostic process that allows pronator syndrome to be differentiated reliably from carpal tunnel syndrome remains a challenge for clinicians, as evidenced by the most common cause of pronator syndrome misdiagnosis: carpal tunnel syndrome. Pronator syndrome can be caused by compression of the median nerve as it passes through the anatomical structures of the forearm, while carpal tunnel syndrome refers to one particular topographic area within which compression occurs, the carpal tunnel. The present narrative review is a complex clinical comparison of the two syndromes with their anatomical backgrounds involving topographical relationships, morphology, clinical picture, differential diagnosis, and therapeutic options. It discusses the most frequently used diagnostic techniques and their correct interpretations. Its main goal is to provide an up-to-date picture of the current understanding of the disease processes and their etiologies, to establish an appropriate diagnosis, and introduce relevant treatment benefiting the patient.

Percutaneous Ultrasound-Guided Release of the Lacertus Fibrosus for Median Nerve Entrapment at the Elbow.

PURPOSE: The aim of this technical note is to present a microinvasive percutaneous ultrasound-guided release of the lacertus fibrosus of the biceps brachii for pronator syndrome, i.e., entrapment of the median nerve at the elbow. METHODS: Fifteen consecutive patients were included. Patients showed isolated pronator syndrome including pain plus reduced strength of specific median nerve innervated muscles. The release was performed in a non-operating interventional room under wide-awake local anesthesia no tourniquet (WALANT). It was conducted superficial to the pronator teres with in-plane ultrasound guidance. The recovery of strength was first assessed peroperatively, and then systematic visits at postoperative weeks 1 and 4 included assessments of both strength and pain. RESULTS: Procedures were comfortably completed with no immediate surgical or anesthetic complication. Muscle strength returned immediately and persisted at postoperative visits. Visual analog scores for pain reduced from 6.2 to 2.5 and 0.6 at weeks 1 and 4, respectively. All working patients were able to perform in their professional activities at week 1. The millimetric skin incision healed with no hypertrophic scar tissue. A small hematoma occurred at week 1 and resorbed spontaneously. No other delayed complication was observed. The procedure appeared effective with improved invasiveness compared to existing techniques. Real-time monitoring with ultrasound may improve the safety. The technique could be regarded as a new ultrasound-guided alternative to surgery. CONCLUSION: Performed superficial to the pronator teres muscle under WALANT anesthesia, the microinvasive percutaneous ultrasound-guided release of the lacertus fibrosus may be an effective treatment of pronator syndrome.

Proximal Median Nerve Compression in the Differential Diagnosis of Carpal Tunnel Syndrome.

Carpal tunnel syndrome (CTS) is the most common median nerve compression neuropathy. Its symptoms and clinical presentation are well known. However, symptoms at median nerve distribution can also be caused by a proximal problem. Pronator syndrome (PS) and anterior interosseous nerve syndrome (AINS) with their typical characteristics have been thought to explain proximal median nerve problems. Still, the literature on proximal median nerve compressions (PMNCs) is conflicting, making this classic split too simple. This review clarifies that PMNCs should be understood as a spectrum of mild to severe nerve lesions along a branching median nerve, thus causing variable symptoms. Clear objective findings are not always present, and therefore, diagnosis should be based on a more thorough understanding of anatomy and clinical testing. Treatment should be planned according to each patient's individual situation. To emphasize the complexity of causes and symptoms, PMNC should be named proximal median nerve syndrome.

Is Carpal Tunnel Release an Effective Treatment for Patients with Suspected Concurrent Carpal Tunnel and Pronator Syndrome?

Background: Some patients with a confirmed diagnosis of carpal tunnel syndrome (CTS) on clinical examination and electrodiagnostic testing (EDX) may also have one or more clinical features of pronator syndrome (PS). However, the EDX is negative for PS. We label these patients as suspected concurrent carpal tunnel and pronator syndrome (CCPS). We suspect that this is a presentation of reverse double crush syndrome that occurs when a symptomatic distal compression neuropathy converts an asymptomatic proximal compression into a symptomatic one. We believe both compressions can be relieved by decompressing the median nerve only at the wrist. The aim of our study is to determine whether carpal tunnel release (CTR) is an effective treatment for patients suffering from CCPS. Methods: This is a prospective, cohort study of the outcomes of CTR in two matched groups with 37 patients in each group. Group A included patients with suspected CCPS and group B included patients with isolated CTS. All patients were evaluated pre-operatively and 1 year after surgery using the Boston Carpal Tunnel Questionnaire (BCTQ). At one year, patients were also assessed for residual symptoms and positive provocative tests. Results: A significant improvement in the symptom and functional severity scales (SSS and FSS) of the BCTQ was noted in both groups. The degree of improvement in SSS was similar in both groups; however, group A showed a greater improvement in FSS. This could be attributed to higher pre-operative values in some items of FSS in group A. No patients in either group had residual symptoms severe enough to necessitate further treatment. Conclusion: The outcomes of CTR are similar in patients with isolated CTS and suspected CCPS and a CTR may be sufficient to address symptoms of CTS and PS in patients with CCPS. Level of Evidence: Level II (Therapeutic).

Some Misconceptions in the Treatment of Cubital Tunnel Syndrome, Radial Tunnel Syndrome, and Median Nerve Compression in the Forearm.

This article discusses ulnar, median, and radial nerve compression in the proximal forearm and elbow and some possible common misconceptions. In particular, the ligament of Struthers extremely rarely causes ulnar neuropathy. Lacertus syndrome and flexor superficialis-pronator syndrome can be diagnosed separately. Surgical release can be through a small incision. Acronyms for compression to radial nerve in proximal forearm can be simplified to radial tunnel syndrome, which includes a mild type (classical radial tunnel syndrome) and a severe type (posterior interosseous nerve (PIN) compression).

Endoscopic Proximal Median Nerve Decompression: An Alternative Treatment for Pronator Syndrome.

Proximal forearm median nerve compressive neuropathy, termed as pronator syndrome, is difficult to diagnose and often overlooked. Its symptoms include vague proximal volar forearm pain that may be associated with paresthesia and numbness in the median nerve distribution. Weakness is typically not present. The treatment of pronator syndrome is largely nonsurgical, consisting of activity modification, anti-inflammatory medication, corticosteroid injections, stretching, and periods of splinting. Surgery is indicated when conservative therapy fails; however, there is no consensus on the treatment approach or technique. Most decompressions are performed using an open technique through a variety of incisions. Recently, endoscopic approaches have drawn an interest. This article describes a technique for endoscopic proximal median nerve decompression that enables the complete decompression of the median nerve in the distal aspect of the arm and proximal aspect of the forearm through a small incision, potentially minimizing surgical morbidity and reducing healing time.

Median Nerve Compression in the Forearm: A Clinical Diagnosis.

Background: Median nerve entrapment in the forearm (MNEF) without motor paralysis is a challenging diagnosis. This retrospective study evaluated the clinical presentation, diagnostic studies, and outcomes following surgical decompression of MNEF. Methods: The study reviewed 147 patient medical charts following MNEF surgical decompression. With exclusion of patients with combined nerve entrapments (radial and ulnar), polyneuropathy, neurotmetic nerve injury, or median nerve motor palsy, the study sample included 27 patients. Data collected include: clinical presentation and pain, strength, provocative testing, functional outcomes, and Disabilities of the Arm, Shoulder and Hand (DASH) scores. Results: The study included 27 patients (mean follow-up = 7 months), and 13 patients had previous carpal tunnel release (CTR). Clinical presentation included pain (n = 27) (forearm, n = 22; median nerve innervated digits, n = 21; and palm, n = 21) and positive clinical tests (forearm scratch collapse test, n = 27; pain with compression over the flexor digitorum superficialis arch/pronator, n = 24; Tinel sign, n = 11). Positive electrodiagnostic studies were found for MNEF (n = 2) and carpal tunnel syndrome (n = 11). Primary CTR was performed in 10 patients and revision CTR in 7 patients. Postoperatively, there were significant (P < .05) improvements in strength, pain, quality of life, and DASH scores. Conclusions: The MNEF without motor paralysis is a clinical diagnosis supported by pain drawings, pain quality, and provocative tests. Patients with persistent forearm pain and median nerve symptoms (especially after CTR) should be evaluated for MNEF. Surgical decompression provides satisfactory outcomes.

Uncommon compressive neuropathies of upper limbs.

To present the clinical features of less common entrapment neuropathies of upper limbs, introduce diagnostic tools, comment on the general bases of treatment, and create awareness of these conditions. Although these conditions are rare, adequate and rapid diagnosis is necessary to initiate appropriate treatment in a timely manner, in order to avoid further nerve insults, associated muscle atrophy, and their consequences in quality of life.

Rare case of median nerve and brachial artery entrapment by an abnormal musculo-fascial tunnel in the arm: possible cause of neurovascular compression syndrome.

Entrapment neuropathies of the peripheral nervous system are frequently encountered due to anatomical variations. Median nerve is the most vulnerable nerve to undergo entrapment neuropathies. The clinical complications are mostly manifested by median nerve impingement in forearm and wrist areas. Median nerve entrapment could also occur at the arm, due to the presence of ligament of Struthers. Here we report a rare case of proximal entrapment of median nerve and brachial artery in the arm by an abnormally formed musculo-fascial tunnel. The tunnel was formed by the muscle fibers of brachialis and medial intermuscular septum in the lower part of arm. Due to this, the median nerve coursed deep, below the tunnel and continued distally into the forearm, underneath the pronator teres muscle and hence did not appear as a content of cubital fossa. The present entrapment of neurovascular structures in the tunnel might lead to pronator syndromes or other neurovascular compression syndromes.

Immediate improvements of supination range of motion and strength following pronator teres muscle friction massage: a clinical trial comparing people with and without supination limited motion.

OBJECTIVES: To investigate the effects of friction massage techniques on the pronator teres muscle on supination range of motion (ROM) and supinator strength in individuals with and without limited supination ROM. METHODS: In total, 26 subjects (13 with limited supination ROM and 13 healthy subjects) volunteered to participate in this study. We used a customized wrist cuff. Supination ROM and supinator strength were measured with a 9-axis inertial motion sensor and load cell. The friction massage protocol was executed with the pronator teres muscle in a relaxed position. Then supination ROM and supinator strength were measured again. RESULTS: There was no significant interaction effect on supination ROM, which was significantly greater in the limited supination and control groups. A post hoc t-test revealed that the limited supination group achieved a significantly increased post-test supination ROM (51.7 ± 7.8°) compared to the pre-test value (43.6 ± 5.2°). In addition, the control group achieved a significant increase in post-test supination ROM (67.7 ± 10.0°) compared to the pre-test value (61.4 ± 7.7°). There was no significant interaction effect on supinator strength. Supinator strength was significantly greater in the limited supination and control groups. A post hoc t-test revealed a significant difference in supinator strength between the pre- and post-test values in the limited supination group. DISCUSSION: Friction massage helps restore a limited ROM of the forearm supination motion and immediately increases supinator muscle strength. This technique can be used as an intervention method to improve muscle strength in patients with limited supination ROM.

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.

Role of pronator release in revision carpal tunnel surgery.

INTRODUCTION: The purpose of this study was to compare the result of treatment of patients with failed primary carpal tunnel surgery who suspected pronator teres syndrome (PTS) by performing revision carpal tunnel release (CTR) with pronator teres release (PTR) and revision CTR alone. METHODS: Retrospective chart review in patients who required revision CTR and suspected PTS. Group 1, treated by redo CTR with PTR and group 2, treated by redo CTR alone. Intraoperative findings, pre and postoperative numbness (2-PD), pain (VAS score), and grip strength were studied. RESULTS: There were 17 patients (20 wrists) in group 1 and 5 patients (5 wrists) in group 2. Patients in group 1 showed more chance of fully recovery of numbness and pain than group 2 (60% vs. 0%, p < 0.05 and 55.0% vs. 0%, p < 0.05, respectively). Mean grip strength was increased 16.0% in group 1 and increase 11.7% in group 2. Most common pathology at the elbow were deep head of pronator teres 90% (18/20 elbows) and lacertus fibrosus 50% (10/20 elbows). The most common finding at carpal tunnel was the reformed transverse carpal ligaments (80%, 20/25 wrists) and scar adhesion around the median nerve (40%, 10/25 wrists). DISCUSSION: Intraoperative findings from our study confirmed that there were pathology in both carpal tunnel and pronator area in failed primary CTR with suspected PTS. Our study showed that combined PTR with revision CTR provided higher chance of completely recovery from numbness and pain more than redo CTR alone.