Ulnar tunnel syndrome

Ultrasound of the Ulnar Nerve: A Pictorial Review: Part 2: Pathological Ultrasound Findings

This is the second part of a two-part article in which we focus on the ultrasound (US) appearance of the pathological ulnar nerve (UN) and its main branches. Findings in a wide range of our pathological cases are presented with high-resolution US images obtained with the latest-generation US machines and transducers.

Neurectomy of the Nerve of Henle Associated with Periarterial Sympathectomy for Management of Intractable Raynaud Phenomenon

BACKGROUND

In periarterial sympathectomy for intractable Raynaud phenomenon, the extent of adventitectomy and postoperative outcomes and hand perfusion assessment tools remain debatable. The authors evaluated the outcome of neurectomy of the nerve of Henle combined with ulnar tunnel release and periarterial adventitectomy in the treatment of refractory Raynaud phenomenon using objective measurements and patient-reported outcomes.

METHODS

Nineteen patients with 20 affected hands were prospectively enrolled and underwent the proposed procedures from 2015 to 2021. Relevant data, including Michigan Hand Outcomes Questionnaire and 36-Item Short Form health questionnaire scores, were documented for analysis during a 3-year follow-up.

RESULTS

The average ingress value of the three measured fingers (index, long, and ring) on indocyanine green angiography increased after surgery ( P = 0.02). The median number of ulcers decreased ( P < 0.001), and the median digital skin temperature increased ( P < 0.001). Questionnaire scores showed improvement in physical aspects, such as overall hand function ( P ≤ 0.001), activities of daily living ( P = 0.001), work performance ( P = 0.02), pain ( P < 0.001), physical function ( P = 0.053), and general health ( P = 0.048), and mental aspects, such as patient satisfaction ( P < 0.001) and mental health ( P = 0.001). The average indocyanine green ingress value of the three measured fingers significantly correlated with the patient-reported outcomes, including overall hand function ( r = 0.46, P = 0.04), work performance ( r = 0.68, P = 0.001), physical function ( r = 0.51, P = 0.02), and patient satisfaction ( r = 0.35, P= 0.03).

CONCLUSIONS

The proposed surgical procedures provided satisfactory outcomes, both subjectively and objectively, over a follow-up period of up to 3 years. Indocyanine green angiography may provide rapid and quantitative measurements for perioperative hand perfusion assessment.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Outcomes of ulnar nerve decompression for double crush syndrome

BACKGROUND

Double crush syndrome (DCS) of the ulnar nerve, including cubital tunnel syndrome with ulnar tunnel syndrome (UTS), is uncommon. This study compares the postoperative outcomes of patients with isolated ulnar tunnel syndrome versus those with double crush syndrome of the elbow and ulnar tunnel.

METHODS

This study enrolled 22 patients: 12 underwent cubital tunnel surgery and ulnar tunnel surgery (double crush group); and 10 underwent only ulnar tunnel decompression (isolated UTS group). Postoperative effect evaluation of patients in both groups after at least 2.6 years (mean, 5.1 years and 5.7 years, respectively). Statistical analysis compared postoperative function, physical examination, and patient-reported satisfaction between groups.

RESULTS

In terms of postoperative grip strength, there was no difference between the postoperative states of the two groups (0.88 ± 0.04 versus 0.87 ± 0.05), while there was statistical difference in terms of the increment of the grip strength (p = 0.036); the two-point discrimination of isolated UTS group is better than the double crush group (90% versus 83.3%); double crush patients reported lower satisfaction than the UTS group (90% versus 83.3%).

CONCLUSIONS

At a minimum of 2.6 years after the nerve decompression, the patients of isolated UTS group are likely to have superior grip strength increment than patients with a history of double crush surgery, and there is no big difference in the final recovery situation. The sensation and satisfaction of isolated UTS group after nerve release were better compared with patients following double crush surgery.

Ultrasound of the Hook of Hamate Region: Pictorial Review

The hook of hamate is a complex anatomical region with many small but important structures. A sound knowledge of anatomy along with a systematic ultrasound technique can help delineate a variety of disorders. In this pictorial review, we discuss the ultrasound anatomy and the possible pathologies that can be encountered in this region.

Prospective outcome analysis of ulnar tunnel syndrome: Comparing traumatic versus non-traumatic etiologies

BACKGROUND

Ulnar tunnel syndrome (UTS) is relatively uncommon compared to the carpal tunnel or cubital tunnel syndromes. Few reports dedicated to the functional outcomes after surgical intervention of the UTS exist. Herein we compare the outcomes of patients with UTS of different etiologies.

METHODS

Patients diagnosed with UTS between 2016 and 2020 were recruited. Ulnar tunnel release was performed in all patients, along with other necessary osteosynthesis or reconstructive procedures in the traumatic group. Patients were followed-up every six months post-operatively. Outcomes measured include: objective evaluations, subjective questionnaires, records of clinical signs, and grading of the British Medical Research Council scale for intrinsic muscle strength.

RESULTS

21 patients were recruited, and favorable results were noted in all of them after surgery. Traumatic UTS patients had a worse initial presentation than the non-traumatic cases, but had a greater improvement after surgery and yielded outcomes comparable with those of the patients without trauma. Patients with aberrant muscles in their wrists had better outcomes in some objective measurements than those without aberrant muscles.

CONCLUSIONS

Ulnar tunnel release improves the outcome of patients regardless of the etiology, especially in patients with trauma-induced UTS. Thus, a proper diagnosis of the UTS should be alerted in all patients encountering paresthesia in the ulnar digits, ulnar-sided pain, weakness of grip strength, or intrinsic weakness to ensure good outcomes.

Pigmented Villonodular Synovitis as an Atypical Cause of Deep Motor Branch Neuropathy

Objectives

Compression of the ulnar nerve in Guyon's canal results in ulnar tunnel syndrome (UTS). The patient may present with sensory and motor deficits (zone 1), motor deficit (zone 2), or sensory deficit (zone 3). The most common causes of UTS include ganglion cysts, idiopathic ulnar nerve compression, occupational pressure neuritis (repetitive compression), prolonged compression, hook of hamate fractures, and arterial thrombus or aneurysm.

Case Report

We report an atypical cause of UTS involving pigmented villonodular synovitis (PVNS) with a review of the literature. Surgical decompression of the ulnar nerve at Guyon's canal has resulted in resolving motor weakness and improved interosseous strength at latest follow-up.

Conclusion

The most common causes of UTS are ganglion, occupational neuritis, prolonged compression, and ulnar artery thrombi/aneurysms. However, other more rare causes such as PVNS should be considered in the appropriate patient.

Clinical Features of Ulnar Tunnel Syndrome and the Diagnostic Value of Nerve Conduction Measurements

Objectives

The purposes of this study were to assess the clinical features of ulnar tunnel syndrome (UTS) and to investigate the diagnostic value of nerve conduction measurements for UTS.

Methods

Eighteen patients with UTS were reviewed retrospectively. Fifteen patients had intrinsic muscle atrophy and motor weakness, and 15 had numbness with hypesthesia. The compound muscle action potentials (CMAPs) from the first dorsal interosseous (FDI) muscle and the abductor digiti minimi (ADM) muscle and the sensory nerve action potential (SNAP) from the little finger were recorded and analyzed. All patients underwent ulnar tunnel release surgery and neurolysis. Static two-point discrimination test results and pinch strengths were assessed before and after surgery.

Results

Before surgery, FDI-CMAP was recorded in 17 patients, and ADM-CMAP in 16, and all showed delayed latency and/or low amplitude. SNAP was recorded in eight patients and two showed delayed latency. The causes of ulnar nerve lesions were ganglion in five patients, traumatic adhesion in four, ulnar artery aberrancy in four, pisohamate arch in three, anomalous muscle in one, and ulnar vein varix in one. The sites of the lesions were in zone 1 of the ulnar tunnel anatomy in 12 patients, in zone 2 in 2, and in zones 1 and 2 in 4. After surgery, all patients obtained recovery of motor function and sensation; however, postoperative FDI-CMAP and ADM-CMAP did not improve to the normal range.

Conclusions

The causes of UTS were ganglion, traumatic adhesion, ulnar artery aberrancy, and pisohamate arch. Both FDI-CMAP and ADM-CMAP were valuable for electrophysiological diagnosis of UTS.

End-to-Side Anterior Interosseous Nerve Transfer: A Valuable Alternative for Traumatic High Ulnar Nerve Palsy

BACKGROUND

The prognosis of high ulnar nerve injury is poor despite nerve repair or grafting. Anterior interosseous nerve (AIN) transfers provide a satisfactory recovery. However, the efficacy of end-to-side (ETS) AIN transfer and optimal timing in Sunderland grade IV/V of high ulnar nerve injury is lacking.

OBJECTIVE

The goals were to compare the outcomes of high ulnar nerve injury managed with ETS AIN transfers with those managed with conventional procedures (nerve repair or graft only) and identify differences between early and delayed transfers.

METHODS

Patients with isolated high ulnar nerve injury (Sunderland grade IV/V) from 2010 to 2017 were recruited. Patients with conventional treatments and AIN transfers were designated as the control and AIN groups, respectively. Early transfer was defined as the AIN transfer performed within 8 weeks postinjury. Outcomes were measured and analyzed by the British Medical Research Council (BMRC) score, grip strength, and pinch strength.

RESULTS

A total of 24 patients with high ulnar nerve injury (Sunderland grade IV/V) were included. There were 11 and 13 patients in the control and AIN groups, respectively. In univariate analysis, both early and delayed AIN transfers demonstrated significantly better motor recovery among BMRC score and strength of grip and pinch at 12 months (P < 0.05). No statistical significance was found between early and delayed transfer. In multivariate analysis, both early and delayed transfers were regarded as strong and independent factors for motor recovery of ulnar nerve. Compared with the control, early [odds ratio (OR), 1.83; P < 0.001] and delayed (OR, 1.59; P < 0.001) transfers showed significant improvement with regard to BMRC scores. The pinch strength in early (OR, 31.68; P < 0.001) and delayed (OR, 26.45; P < 0.001) transfers was also significantly better.

CONCLUSION

The ETS AIN transfer, in either early or delayed fashion, significantly improved intrinsic motor recovery in high ulnar nerve injuries classified as Sunderland grade IV/V. The early transfer group demonstrated a trend toward better functional recovery with less downtime.

Ulnar tunnel syndrome: pathoanatomy, clinical features and management

Ulnar tunnel syndrome is compression of the ulnar nerve at the level of the wrist within Guyon's canal. It is most commonly caused by a ganglion cyst but may also be secondary to fractures, inflammatory conditions, neoplasm, vascular anomalies, aberrant musculature or a combination of these. Assessment should include a detailed history focusing on duration, site and progression of symptoms. The level of compression can be estimated clinically on examination by assessing motor and sensory changes in the hand. Investigations are used to confirm diagnosis or to clarify the underlying cause. X-rays and computed tomography can be used to exclude fractures. Ultrasound is used to diagnose ganglion cysts and vascular anomalies, and can localise the level of compression. Nerve conduction studies can be used to support the diagnosis and look for proximal compression. Mild symptoms can be managed non-operatively. Surgical exploration and decompression is the gold standard treatment for neuro-compressive causes with largely good outcomes.

Tortuous ulnar artery presenting as left distal forearm mass

Knowledge of anatomic variation in vasculature is critical to safe medical intervention as conduits vary in morphology, architecture, and course. Tortuosity is a common anatomic variant in certain arterial beds; however, its prevalence in ulnar arteries is not well documented in the literature. Here we report two cases of tortuous ulnar arteries in patients being evaluated for upper extremity hemodialysis access.

Clinical and Ultrasonographic Features of Distal Ulnar Neuropathy: A Review

Focal ulnar neuropathy at the wrist is a rare but problematic disorder often associated with the unique anatomy of this nerve as it courses through Guyon's canal, a superficial fibro-osseous tunnel in the proximal ulnar palm. The electrophysiologic features of this disorder have been well-characterized, but the sonographic anatomy of the nerve across the wrist and palm has yet to be systematically described in normal and abnormal states. In this review, we describe the basic anatomy and the sonographic appearance of the nerve in the wrist and palm in normals and individuals with pathology. The value of using US in conjunction with electrodiagnostic testing is emphasized as the two tests together provide critical information regarding etiology, predisposing factors, and functional significance. Furthermore, ultrasound is useful as a patient educational tool to promote behavioral changes that assist in nerve recovery when pathology is related to repetitive stress.

Ulnar neuropathy at wrist: entrapment at a very "congested" site

Ulnar tunnel syndrome indicates ulnar neuropathy at different sites within the wrist. Several classifications of ulnar tunnel syndrome are present in literature, based upon typical nerve anatomy. However, anatomical variations are not uncommon and can complicate assessment. The etiology is also complex, due to the numerous potential causes of entrapment. Clinical examination, neurophysiological testing, and imaging are all used to support the diagnosis. At present, many therapeutic approaches are available, ranging from observation to surgical management. Although ulnar neuropathy at the wrist has undergone extensive prior study, unresolved questions on diagnosis and treatment remain. In the current paper, we review relevant literature and present the current knowledge on ulnar tunnel syndrome.

A minimally invasive approach for cubital tunnel release and ulnar nerve transposition

OBJECTIVES

The aim of the study is to introduce a new minimally invasive technique for ulnar nerve release and transposition.

METHODS

From January 2010 to May 2011, 51 patients with cubital tunnel syndrome were treated through a 1.5 to 2 cm incision. Limb functional recovery, scar esthetics, sensitivity of scar, numbness of the operating area, and patient satisfaction were assessed.

RESULTS

No wound hematoma nor infection was observed in the group. The time of operation was 36 ± 17.2 minutes. At the final follow-up of 63 ± 7.3 months, 2-point discrimination of the small finger was improved from 6.3 ± 2.2 mm to 5.2 ± 2.4 mm. Grip and pinch strength of the hand were improved from 14.2 ± 7.7 kg and 3.7 ± 2.4 kg to 35.2 ± 12.7 kg and 4.1 ± 2.8 kg, respectively. The motor nerve conduction velocity was improved from 36.5 ± 11.2 to 44.6 ± 6.7 (m/sec). The Disabilities of the Shoulder, Arm, and Hand questionnaire score was improved from 37.2 ± 23.8 to 10.5 ± 9.6. No patients reported scar pain, sensitivity of scar, or numbness of the operating area. No revision surgery was needed. Michigan Hand Outcome score for aesthetics was 94.6%±5.1 and satisfaction was 92 ± 8, respectively. We obtained 33 excellent, 12 good, 5 fair, and 1 poor result.

CONCLUSION

Ulnar nerve decompression with anterior transposition can be safely and effectively accomplished through the small incision. It can be an alternative technique producing good appearance.

ELBOW ULNAR NEUROPATHY: TREATMENT BY ANTERIOR TRANSPOSITION OF THE ULNAR NERVE

Objectives:

Retrospective clinical evaluation of 31 patients who underwent ulnar nerve decompression at the elbow and subcutaneous anterior transposition.

Methods:

From January 2000 to December 2013, 71 patients underwent subcutaneous anterior transposition of the ulnar nerve. Thirty-one patients returned for evaluation. The mean follow-up period was 60 months. Patients were evaluated for the degree of satisfaction after surgery, paresthesia, pain, Tinel sign, Froment test and sensitivity test by esthesiometer, muscle strength of the intrinsic muscles and deep flexor of the fifth digit, visual analogic pain scale (VAS) and were subjected to the QuickDash questionnaire.

Results:

Thirty-nine per cent of patients had compression on the right side and 61% on the left side. Sixty-one percent were idiopathic, 35% post traumatic and 3% had Poems syndrome. Forty-eight per cent of patients were very much satisfied after surgery and 52% were satisfied. Forty-eight per cent had paresthesia after surgery and 52% did not.

Conclusion:

The ulnar neurolysis of the cubital tunnel with anterior subcutaneous transposition is a safe and effective technique for treating idiopathic or post-traumatic compressive neuropathy, with high success rate and excellent function for activities of daily living. Level of Evidence IV, Case Series.

Ulnar Neuropathy in Cyclists

The form and function of the cyclist exposes the ulnar nerve to both traction and compressive forces at both the elbow and wrist. Prevention of ulnar neuropathy and treatment of early symptoms include bike fitting, avoidance of excessive or prolonged weight-bearing through the hands, and the use of padded gloves. For persisting or progressive symptoms, a thorough history and physical examination is essential to confirm the diagnosis and to rule out other sites of nerve compression. The majority of compression neuropathies in cyclists resolve after appropriate rest and conservative treatment; however, should symptoms persist, nerve decompression may be indicated.

Analysis of the position of the branches of the ulnar nerve in Guyon's canal using high-resolution MRI in positions adopted by cyclists

PURPOSE

To study variations in the anatomical relationships of the branches of the ulnar nerve in Guyon's canal relative to the hamulus of hamate (HH) in a grip encountered among cyclists.

MATERIALS AND METHODS

Forty-seven wrist examinations were performed on a 3-T MRI (soft antenna, 16 channels) in propeller sequence in the plane perpendicular to the carpus in 28 healthy volunteers in three cycling positions (neutral, hyperextension and ulnar deviation). The positions and distance between the superficial (SB) and deep (DB) branches of the ulnar nerve with respect to the HH were determined on the section passing through the HH.

RESULTS

The mean distances between the SB (d s) and DP (d p) and HH were 2.4 and 0.6 mm, respectively. The d s in hyperextension and ulnar deviation were 2.2 mm (P = 0.3) and 3 mm (P = 0.07), respectively. The d p in hyperextension and ulnar deviation were 0.3 mm (P = 0.02) and 0.5 mm (P = 0.15), respectively. Hyperextended, 60 % of SB and 40 % of DB were close to the HH, and 26 % of DB came directly in contact with it. In ulnar deviation, 30 % of SB and 29 % of DB approached HH, and 47 % of DB were in contact with it.

CONCLUSION

This study shows that SB and DB positions of the ulnar nerve vary with respect to the HH depending on the position of the wrist, and such differences may promote Guyon's canal syndrome in cyclists.

Diagnosis of Severe Carpal Tunnel Syndrome Using Nerve Conduction Study and Ultrasonography

This study investigated the correlation between nerve conduction study and ultrasonographic findings for assessment of the usefulness of ultrasonography in determining carpal tunnel syndrome severity. Hands of adults with carpal tunnel syndrome were assessed using ultrasound and nerve conduction studies and grouped according to median nerve cross-sectional area (CSA). There were significant differences (p < 0.01) in mean median nerve CSA between controls, patients with median sensory nerve conduction velocity ≤40 m/s and patients with absent sensory nerve action potential and between controls, patients with median nerve distal motor latency ≥4.5 ms and patients with absent compound muscle action potentials of the abductor pollicis brevis. This is the first report to define median nerve CSA cutoff values (18 mm(2)) for determining carpal tunnel syndrome severity in patients with absent compound muscle action potentials of the abductor pollicis brevis. Median nerve CSA values below the cutoff values should prompt clinicians to consider other disorders, such as cervical compressive myelopathy.

Ultrasound-Guided Perineural Injection at Guyon's Tunnel: An Anatomic Feasibility Study

Compression of the ulnar nerve (UN) at the wrist causes neuropathy in the ulnar tunnel (UT), or Guyon's tunnel. In the absence of trauma and motor syndromes, primarily conservative treatment is considered. As in carpal tunnel syndrome, a perineural injection of corticosteroids may be beneficial. The aim of this study was to investigate the feasibility of ultrasound-guided injections at the UT. We performed ultrasound-guided injections of ink at the UN within the UT in 21 limbs from 11 non-embalmed cadavers. In all cases, we stained the perineural sheath of the superficial branch of the ulnar nerve within the UT. No ink was found inside the nerve or in adjacent structures such as blood vessels and tendons. In conclusion, perineural injection of the UN in the UT seems to be a technically feasible procedure. On the basis of these anatomic data, clinical trials are needed to prove the concept for routine use.

A rare case of a punched nerve syndrome of the deep motor branch of the ulnar nerve

INTRODUCTION

Peripheral compression neuropathy of the ulnar nerve is a frequent condition, most likely encountered at the ulnar sulcus or the Guyon's canal. High-resolution ultrasound (HRUS) can often identify the site of injury. Primarily idiopathic, compression neuropathy can stem from a punched nerve syndrome, in which direct contact between an arterial branch and the nerve leads to compression.

MATERIALS AND METHODS

A 42-year-old male patient was examined by means of HRUS using a 17-5 MHz linear transducer on a Philips iU22(®) (Philips, Bothell, Washington, USA).

RESULTS

After reporting a punched nerve syndrome of the deep motor branch of the ulnar nerve distal to the Guyon's canal, the patient underwent surgery and showed electrophysiological and clinical improvement 6 months after decompression.

CONCLUSION

HRUS is a viable method to demonstrate a punched nerve syndrome. In conjunction with clinical presentation, even unlikely sites of compression such as the deep motor branch of the ulnar nerve can be identified.

Ultrasound of the hand and wrist

There have been immense technical innovations and broadened clinical applications of ultrasound in the musculoskeletal system over the past 20 years. Specifically with regard to the hand and wrist, the advent of higher resolution transducers and postprocessing software applications have resulted in overall enhanced visualization of soft tissue structures (tendons/ligaments) as well as surface osseous lesions such as subclinical erosions in rheumatoid arthritis. Quantitative ultrasound, using either power Doppler or contrast-enhanced imaging, has become a central outcomes measure used to evaluate and document patient response to treatment in inflammatory arthropathies such as rheumatoid arthritis. This review will summarize the current state of clinical applications of ultrasound in the evaluation of the hand and wrist, with a summary of technical advances and specific applications in rheumatologic conditions.This review was exempt from institutional review board approval.

Guyon canal: the evolution of clinical anatomy

Guyon canal refers to the ulnar tunnel at the wrist named for the French surgeon Jean Casimir Félix Guyon, who described this space in 1861. After Guyon's description, clinicians have focused their interest on symptoms caused by compression of structures occupying this canal (later named ulnar tunnel syndrome or Guyon syndrome). However, disagreement and confusion persisted over the correct anatomical boundaries and terminology used to describe the ulnar tunnel. Through anatomical investigation and evolving clinical case studies, the current understanding of the anatomy of the ulnar tunnel was established. This article examines the evolution of the anatomical description of the ulnar tunnel and its relevant clinical associations and casts light on the life and contributions of Guyon.

Ultrasonography for nerve compression syndromes of the upper extremity

Nerve compression syndromes commonly involve the nerves in the upper extremity. High-resolution ultrasonography (US) can satisfactorily assess these nerves and may detect the morphological changes of the nerves. US can also reveal the causes of nerve compression when structural abnormalities or space-occupying lesions are present. The most common US finding of compression neuropathy is nerve swelling proximal to the compression site. This article reviews the normal anatomic location and US appearances of the median, ulnar, and radial nerves. Common nerve compression syndromes in the upper extremity and their US findings are also reviewed.