Ultrasound-guided minimally invasive thread release of Guyon's canal: initial experience in cadaveric specimens.

OBJECTIVE: Guyon's canal syndrome is caused by compression of the ulnar nerve at the wrist, occasionally requiring decompression surgery. In recent times, minimally invasive approaches have gained popularity. The aim of this study was to assess the efficacy and safety of ultrasound-guided thread release for transecting the palmar ligament in Guyon's canal without harming surrounding structures, in a cadaveric specimen model. METHODS: After ethical approval, thirteen ultrasound-guided thread releases of Guyon's canal were performed on the wrists of softly embalmed anatomic specimens. Cadavers showing injuries or prior operations at the hand were excluded. Subsequently, the specimens were dissected, and the outcome of the interventions and potential damage to adjacent anatomical structures as well as ultrasound visibility were evaluated with a score from one to three. RESULTS: Out of 13 interventions, a complete transection was achieved in ten cases (76.9%), and a partial transection was documented in three cases (23.1%). Irrelevant lesions on the flexor tendons were observed in two cases (15.4%), and an arterial branch was damaged in one (7.7%). Ultrasound visibility varied among specimens, but essential structures were delineated in all cases. CONCLUSION: Ultrasound-guided thread release of Guyon's canal has shown promising first results in anatomic specimens. However, further studies are required to ensure the safety of the procedure. RELEVANCE STATEMENT: Our study showed that minimally invasive ultrasound-guided thread release of Guyon's canal is a feasible approach in the anatomical model. The results may provide a basis for further research and refinement of this technique. KEY POINTS: • In Guyon's canal syndrome, the ulnar nerve is compressed at the wrist, often requiring surgical release. • We adapted and tested a minimally invasive ultrasound-guided thread release technique in anatomic specimens. • The technique was effective; however, in one specimen, a small anatomic branch was damaged.

Multimodality imaging review of ulnar nerve pathologies.

The ulnar nerve is the second most commonly entrapped nerve after the median nerve. Although clinical evaluation and electrodiagnostic studies remain widely used for the evaluation of ulnar neuropathy, advancements in imaging have led to increased utilization of these newer / better imaging techniques in the overall management of ulnar neuropathy. Specifically, high-resolution ultrasonography of peripheral nerves as well as MRI has become quite useful in evaluating the ulnar nerve in order to better guide treatment. The caliber and fascicular pattern identified in the normal ulnar nerves are important distinguishing features from ulnar nerve pathology. The cubital tunnel within the elbow and Guyon's canal within the wrist are important sites to evaluate with respect to ulnar nerve compression. Both acute and chronic conditions resulting in deformity, trauma as well as inflammatory conditions may predispose certain patients to ulnar neuropathy. Granulomatous diseases as well as both neurogenic and non-neurogenic tumors can also potentially result in ulnar neuropathy. Tumors around the ulnar nerve can also lead to mass effect on the nerve, particularly in tight spaces like the aforementioned canals. Although high-resolution ultrasonography is a useful modality initially, particularly as it can be helpful for dynamic evaluation, MRI remains most reliable due to its higher resolution. Newer imaging techniques like sonoelastography and microneurography, as well as nerve-specific contrast agents, are currently being investigated for their usefulness and are not routinely being used currently.

The elastography of distal ulnar nerve branches in cyclists.

INTRODUCTION: Forced elbow flexion and pressure during bicycling result in ulnar nerve traction and pressure exerted in Guyon's canal or the nerve's distal branches. The compression of the nerves causes a change in their stiffness related to edema and eventually gradual fibrosis. PURPOSE: This study aimed to evaluate the elastography of terminal branches of the ulnar nerve in cyclists. STUDY DESIGN: Cross-sectional study. METHODS: Thirty cyclists, 32 healthy individuals, and 32 volunteers with ulnar nerve entrapment neuropathies participated in the study. Each participant underwent a nerve examination of the cubital tunnel, Guyon's canal and the deep and superficial branches of the ulnar nerve using shear wave elastography. The cyclist group was tested before and after a 2-hour-long workout. RESULTS: Before cycling workouts, the ulnar nerve stiffness in the cubital tunnel and Guyon's canal remained below pathological estimates. Cycling workouts altered nerve stiffness in the cubital tunnel only. Notably, the stiffness of the ulnar terminal branches in cyclists was increased even before training. The mean deep branch stiffness was 50.85 ± 7.60 kPa versus 20.43 ± 5.95 kPa (p < 0.001) in the cyclist and healthy groups, respectively, and the mean superficial branch stiffness was 44 ± 12.45 kPa versus 24.55 ± 8.05 kPa (p < 0.001), respectively. Cycling contributed to a further shift in all observed values. DISCUSSION: These observations indicate the existence of persistent anatomical changes in the distal ulnar branches in resting cyclists that result in increased stiffness of these nerves. The severity of these changes remains, however, to be determined. CONCLUSIONS: These data show elastography values of the ulnar terminal branches in healthy individuals and cyclists where despite lack of clinical symptoms that they seem to be elevated twice above the healthy range.

Diagnosis of ulnar nerve entrapment anterior to the medial epicondyle by ultrasound elastography and diffusion tensor imaging with fiber tractography: a case report.

Ulnar/cubital tunnel syndrome is the second most common compressive neuropathy of the upper limb. Permanent location of the ulnar nerve anterior to the medial epicondyle is extremely rare, with only five cases reported in the literature. Using ultrasound elastography and diffusion tensor imaging with fiber tractography, we diagnosed a case in which ulnar nerve entrapment was associated with anterior nerve location. Surgical release confirmed the diagnosis and the patient was symptom free 3 months after surgery.

Patterns and parameters describing nerve thickening in compression and entrapment ulnar neuropathies at the elbow.

OBJECTIVE: To compare pattern and parameters describing nerve thickening in ulnar neuropathy at the elbow (UNE) due to external compression in the retrocondylar groove (RTC), and entrapment under the humeroulnar aponeurosis (HUA). METHODS: In a group of our previously reported UNE patients we ultrasonographically (US) measured ulnar nerve cross-sectional areas (CSA) on 6-8 standard locations in the elbow segment. We compared CSA patterns in both groups, and determined diagnostic utility of selected CSA based parameters. RESULTS: We studied 79 patients (81 arms) with UNE due to external compression, and 53 patients (55 arms) due to entrapment. Maximal ulnar nerve CSA (>16 mm2), maximal CSA change (>7 mm2/1-2 cm) and maximal/minimal CSA ratio (>2.6) were significantly larger in UNE due to entrapment. They also differentiated these arms from arms with compression with sensitivities of 78%, 87% and 80%, and specificities of 90%, 94%, and 85%, respectively. CONCLUSION: Maximal difference in CSA between points separated by 1-2 cm (>7 mm2/1-2 cm) very efficiently differentiated between UNE due to external compression and entrapment. SIGNIFICANCE: The proposed parameter will hopefully complement precise localization in determining underlying mechanism of UNE. This may help physicians to determine the most appropriate treatment for UNE and possibly other focal neuropathies of unknown cause; i.e., conservative treatment for external compression and surgery for entrapment.

Isolated compression of the ulnar motor branch due to carpal joint ganglia: clinical series, surgical technique and postoperative outcomes.

The entrapment of the ulnar nerve in Guyon's canal (GC) is a well-known wrist canalicular syndrome which is usually followed by a gradual combination of both sensitive and motor symptomatology. However, GC nerve compression could also cause a pure hand motor dysfunction. This condition, less frequent than the classic Guyon's syndrome, can be difficult to diagnose. Authors report a case series of eight patients affected by isolated compression of the ulnar nerve motor branch, due to piso-triquetrum or triquetro-hamate joint ganglia. Surgical technique and postoperative outcomes are discussed in this paper. The isolated compression of the ulnar nerve motor branch is a very rare clinical condition which is often linked to several causes. The rarity of the pathology is probably due to lack of knowledge and therefore to the difficulty in formulating a correct diagnosis. Surgical treatment appears to be decisive in most cases, although late diagnosis often leads to incomplete functional recovery.

Shear-wave elastography in the diagnosis of ulnar tunnel syndrome.

An interesting alternative to traditional diagnostic techniques of the upper extremity nerve entrapments might be an ultrasound elastography that has started to gain attention in recent research. The aim of this preliminary study was to verify whether a quantitative analysis of the ulnar nerve stiffness by shear-wave elastography can be used to diagnose ulnar tunnel syndrome (UTS), an ulnar nerve neuropathy at Guyon's canal. The study included 46 patients (39 women) and 39 healthy controls (34 women). All diagnoses in patients and controls were confirmed with nerve conduction studies. Measurements of nerve stiffness were taken at three levels: Guyon's canal (G), distal forearm (DF), and mid forearm (MF). Additionally, the ulnar nerve cross-sectional area at the canal's level was determined by ultrasonography. Patients with UTS presented with significantly greater nerve stiffness than the controls (mean, 99.41 kPa vs. 49.08 kPa, P < 0.001). No significant intergroup differences were found in the nerve elasticity at DF and MF levels (P < 0.836 and P < 0.881, respectively). An ulnar nerve stiffness value of 80 kPa and G:DF and G:MF ratios equal to 1.5 provided 100% sensitivity, specificity, and positive and negative predictive values in the detection of the syndrome. The mean nerve cross-sectional area in the Guyon's canal was significantly greater in patients than in the controls (4.63 mm2, range, 2-7 mm2 vs. 3.23 mm2, range, 2-5 mm2, P < 0.001). In conclusion, we believe that shear-wave elastography has the potential to become a useful adjunct diagnostic test for UTS.

Unusual case of hypotenar Hammer Syndrome and carpal tunnel syndrome association.

BACKGROUND AND AIM OF THE WORK: Hypothenar Hammer Syndrome is a relatively rare disease process caused by repetitive stress or injury to the hypothenar eminence leading to chronic injury to the ulnar artery. Our study reports an unusual case. METHODS: A 57 years old Plumber presented in April 2016 with a history of constant pain and recurrent paresthesia involving the fingers of the right hand for several months, over the previous 1 year, his hand had become more intolerant of exposure to cold temperatures. Angio-RNM and electromyography were performed and showed a severe double compression of ulnar and median nerve and an ulnar artery deformity without thrombosis. Surgery was performed under sedation and axillary anesthesia. RESULTS: After surgery patient' symptoms immediately improved, and within a few months, his hand had normalized. CONCLUSION: Hypothenar Hammer Syndrome is a rare disease process which manifests in certain occupations and activities that put undue stress on the hypothenar area. Furthermore, the carpal tunnel syndrome, a pressure damage of the median nerve, caused by repetitive manual tasks with flexion and extension of wrist has been added as well as hypothenar hammer syndrome which are vascular damages of hand caused by shock-type application of force.

Intraneural microcystic lymphatic malformation of the ulnar nerve at the Guyon canal: Unusual cause of ulnar pain in a child.

We present a case of an unusual cause of ulnar pain on a 9-year-old patient. The patient had pain on the ulnar side of the wrist after a fall. MRI showed a poorly defined lesion on the ulnar nerve at Guyon's canal. The initial diagnosis was traumatic neuropathy. Following conservative treatment of symptoms for one year, the pain started again. Therefore, a new MRI was performed where progression of the lesion was observed. Excision of the lesion was performed and the specimen sent for pathologic analysis. The diagnosis was of microcystic lymphatic malformation. The patient had a satisfactory evolution, with complete resolution. This is the first description of a microcystic lymphatic malformation in an intraneuronal location.

Effect of Carpal Tunnel Syndrome on the Ulnar Nerve at the Wrist: Sonographic and Electrophysiologic Studies.

OBJECTIVES: The aim of this study was to compare the ulnar nerve at the wrist by sonographic and electrophysiologic studies between patients with carpal tunnel syndrome and control participants and to verify the effect of carpal tunnel syndrome of the ulnar nerve at the wrist. METHODS: Forty-two hands of patients with carpal tunnel syndrome and 37 hands of control participants were examined. Electrophysiologic studies of the ulnar nerve were done in all participants. The cross-sectional areas of the median and ulnar nerves at the wrist were evaluated by sonography. Fifteen hands of patients with carpal tunnel syndrome who underwent carpal tunnel release were also evaluated by sonography after the operation. RESULTS: The ulnar nerve cross-sectional area of the patients with carpal tunnel syndrome (mean ± SD, 5.16 ± 1.04 mm(2)) was significantly larger than that of the controls (3.56 ± 0.52 mm(2); P < .0001). After release of the transverse carpal ligament, the cross-sectional area of the ulnar nerve was significantly smaller than the size measured prior to surgery (P < .0001). The cross-sectional area of the median nerve was significantly correlated with that of the ulnar nerve (P < .05). However, no statistically significant difference was found between the patients with carpal tunnel syndrome and controls in ulnar nerve conduction. There were no statistically significant differences in nerve conduction study results or cross-sectional area of the ulnar nerve between patients with carpal tunnel syndrome with and without extramedian symptoms. CONCLUSIONS: The cross-sectional areas of the ulnar and median nerves at the wrist are increased in patients with carpal tunnel syndrome. Also, the cross-sectional area of the ulnar nerve is decreased after carpal tunnel release.

A rare manifestation of sarcoidosis with sensomotoric neuropathy of the ulnar nerve as the only symptom.

A 79-year-old woman was admitted complaining of progressive weakness and numbness of the right hand. The patient was otherwise healthy. The patient's history was unremarkable. Clinical and electrophysiological examination revealed a compression of the ulnar nerve in the ulnar sulcus and in Guyon's canal. Ultrasound evaluation showed a suspicious tumour proximal to the elbow close to the ulnar nerve. The ulnar sulcus was then released and an epineural and perineural lesion 3-4 cm proximal to the sulcus was excised under microscope. The histopathology confirmed the lesion as non-caseating sarcoid granulomas. The patient showed no other signs of systemic sarcoidosis, as neuropathy was the only symptom and the condition improved postoperatively. Sensory deficits and paraesthesia resolved fully. The extension of the minor finger remained slightly inferior compared with the not affected side. Sarcoid neuropathy is a rare neurological complication of sarcoidosis and has to be included in differential diagnosis of nerve conduction impairments.

The effect of medial side repair in terrible triad injury of the elbow.

OBJECTIVE: The aim of this study was to evaluate the effect of surgical repair of the medial collateral ligament and ulnar nerve release in cases of terrible triad injuries of the elbow. METHODS: This study included 16 patients (average age: 34 years) who underwent surgery following a diagnosis of terrible triad injury of the elbow between 1996 and 2007. Average follow up was 34.5 months. In all cases, the radial head was first fixed or replaced and the anterior capsule/coronoid complex and lateral collateral ligament were repaired. The medial side of the elbow was addressed (medial collateral ligament repair and ulnar nerve release) in 8 cases and not addressed in the remaining 8 cases. Range of motion, pain, stability, ulnar nerve symptoms, functional Mayo Elbow Performance Index, and Disabilities of the Arm, Shoulder and Hand scores were documented. Serial X-rays were used to confirm ulnohumeral arthritis and development of ectopic calcification. Ultrasonography or MRI was used to detect ulnar nerve entrapment. RESULTS: Range of motion was slightly more limited in cases where the medial side was not addressed. Ulnohumeral range of motion and flexion degrees were higher in the cases where the medial side was addressed (p<0.05). Serial X-rays demonstrated impending ectopic calcification located at the proximal insertion of medial collateral ligament in patients who did not undergo medial side repair. MRI or ultrasonography confirmed these findings, revealing swollen displaced nerves resembling findings similar to cubital tunnel syndrome. CONCLUSION: Ulnar neuropathy is a common complication after medial collateral ligament injury and prophylactic release will facilitate overall results and postoperative patient satisfaction.

Imaging of ulnar-sided wrist pain.

Pain on the ulnar side of the wrist is a complex diagnostic dilemma. This is mainly due to the small size and complexity of the anatomical structures. The issue is compounded by the occurrence of positive imaging findings that are clinically asymptomatic. This pictorial essay deals with the imaging manifestations of different causes of ulnar-sided wrist pain.

Comparative study of different surgical transposition methods for ulnar nerve entrapment at the elbow.

This study compared the therapeutic effects of two techniques for surgical decompression treatment for ulnar nerve entrapment at the elbow: subcutaneous transposition and modified submuscular transposition with Z-lengthening of the pronator teres origin. A total of 278 patients with ulnar nerve entrapment (McGowan grades I - III) were randomly assigned to undergo one of these techniques. All patients were followed-up for 2 years. The effects were assessed by preoperative and postoperative cross-sectional area, motor conduction velocity, sensory conduction velocity and nerve action potential. All of these parameters improved after surgery in both groups. For patients with grade I disease, there were no significant differences between the two techniques. For patients with grade II and III disease, modified submuscular transposition was associated with significantly greater improvements compared with subcutaneous transposition. In conclusion, subcutaneous ulnar nerve transposition is recommended for grade I patients and modified submuscular ulnar nerve transposition for grade II and III patients.

Ultrasonographic and functional changes of the ulnar nerve at Guyon's canal after carpal tunnel release.

OBJECTIVE: To describe morphologic and functional modifications of the ulnar nerve at the wrist in carpal tunnel syndrome (CTS) after carpal tunnel release (CTR). METHODS: Ultrasonography was used to study the cross sectional area (CSA) of the ulnar nerve at Guyon's canal, before and 1 and 6 months after CTR, in 18 CTS patients. A parallel electrophysiological and clinical analysis was also conducted. RESULTS: CSA of the ulnar nerve significantly increased 6 months after CTR. Ten (55%) cases showed abnormal CSA values compared to a control group before surgery and five (28%) at 6 month follow-up. In addition, there were improvements in the motor and sensory ulnar axon recruitment properties and the conduction values in sensory ulnar fibres. Patients with extra-median distribution of paresthesia (4 subjects) were free from symptoms. CONCLUSIONS: CTR has a significant effect not only on the anatomical geometry of Guyon's canal, but also on the morphology and function of the ulnar nerve. SIGNIFICANCE: In CTS, high pressure in the carpal tunnel may result in anatomical changes of ulnar nerve, thus causing functional impairment to the ulnar fibres. CTR appears to reverse some of this damage.

Use of ultrasonography in ulnar nerve entrapment surgery--a prospective study.

The purpose of our study is to assess the usefulness of high-resolution ultrasonography in observing the morphology and dynamics of the ulnar nerve in the cubital tunnel and also the efficacy of ultrasonography in a more accurate diagnosis and appropriate surgical treatment decision. Cross-sectional area of the ulnar nerves of 40 healthy volunteers in the control group were measured bilaterally at the level of the epicondyle, 2 cm proximal to and 2 cm distal to the epicondyle. Measurements were obtained for elbows both in extension and flexion. Then, we prospectively obtained the cross-sectional area values of 18 patients at the same levels, elbows in extension and flexion position, and compared the data obtained from the patient group and the control group. The differences between the cross-sectional areas of the ulnar nerves in extension and flexion were statistically significant in the patient population (p < 0.001). Mean cross-sectional area of the ulnar nerve in the patient population was calculated as 0.16 cm(2), and we accepted the cut-off point as 0.1 cm(2). This value for cross-sectional area yielded a sensitivity of 90% and a specificity of 100% in diagnosis of ulnar nerve entrapment. Results substantiated conspicuous morphological changes in ulnar nerve during flexion and extension of the elbow. We also observed that as the degree of the nerve displacement by virtue of elbow flexion that is discerned by ultrasonography increased, a more aggressive decompressive surgery was needed for an appropriate treatment.