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.

Uncommon Anatomical Causes of Ulnar Compression: A Narrative Review.

OBJECTIVES: Some patients develop ulnar nerve compression due to rare anatomical variations or malformations. The aims of this review are to provide a comprehensive overview of anatomical structures and variations that can cause ulnar nerve compression and to evaluate treatment options. METHODS: Case reports and case series about rare cases of unusual ulnar nerve compression published from January 2000 until April 2022 were obtained from databases Embase, MEDLINE, and Web of Science. A total of 48 studies describing 64 patients were included in our study. RESULTS: The following structures have proven to cause ulnar nerve compression: anconeus epitrochlearis, accessory abductor digiti minimi, vascular anomalies, palmaris longus, fibrous bands, and flexor carpi ulnaris. All cases except one have had a surgical release of the ulnar nerve resulting in diminished symptoms or complete recovery at follow-up. CONCLUSIONS: In addition to considering common compression points, it is important to be aware that proximal compression symptoms, such as pain and a positive Tinel sign at the medial elbow, may be attributed to a hypertrophic AE or vascular anomaly. Distal compression symptoms encompass swelling, along with pain and a positive Tinel sign at the distal forearm. Various structures contributing to distal compression include an accessory abductor digiti minimi muscle, an accessory or anomalous palmaris longus muscle, or an accessory or hypertrophic flexor carpi ulnaris muscle. The occurrence of fibrous bands exhibits variability, manifesting in diverse locations across the arm.Level of Evidence: IV.

A 10-Year Update of Outcome Measures Used to Assess Results After Surgery for Cubital Tunnel Syndrome: A Systematic Review of the Literature.

HYPOTHESIS: Outcomes reporting for the surgical release of ulnar nerve cubital tunnel entrapment have variability in subjective, objective, and validated measures. The aim of this study is to review the literature to reassess the measures used to report surgical outcomes for ulnar neurolysis at the elbow. METHODS: This study was conducted in accordance with the PRISMA guidelines on systematic reviews. Six electronic databases were queried from the past 10 years using specific search terms and Boolean operators. Two independent reviewers assessed 4290 unique titles and abstracts that were screened for inclusion criteria. Sixty-eight full text articles were included for analysis. RESULTS: Statistical significance was noted in the number of outcome measures reported between studies from journals of impact factor within the first and third quartiles (P = 0.0086) and first and fourth quartiles (P = 0.0247), although no significance exists in the number of cubital tunnel-specific measures based on impact factor (P = 0.0783). Seventy-nine percent (n = 54) of the included studies report subjective measures; 54% (n = 37) included objective measures. Seventy percent (n = 48) of the studies report disease-specific outcome measures. CONCLUSION: There exists a discordance within the literature regarding the most appropriate, descriptive, and translational measures for reporting surgical outcomes of cubital tunnel syndrome. We recommend journal editors implement a requirement that authors reporting outcomes of ulnar nerve decompression must use a standard, validated measure to make comparisons across the literature universal. Furthermore, a minimum of at least 1 subjective and 1 objective measure should be standard.

Ulnar Nerve Compression at the Elbow Secondary to Intramuscular Lipoma of the Flexor Carpi Ulnaris: A Case Report.

CASE: A 62-year-old right-hand-dominant woman presented with 1 year of persistent radiating pain, weakness, and paresthesias in her left forearm and hand. Electromyography findings were significant for ulnar neuropathy distal to the branch innervating the flexor carpi ulnaris (FCU), without superimposed cervical radiculopathy or other focal entrapment neuropathy. During open ulnar nerve neurolysis, an intramuscular lipoma was encountered within the FCU. Lipoma excision and cubital tunnel release with ulnar nerve transposition were performed with complete relief of neuropraxia. CONCLUSION: We demonstrate full neurologic recovery after intramuscular lipoma excision and cubital tunnel release. Although rare, anomalous anatomy and tissue overgrowth should remain on the differential for patients presenting with atypical neuropraxia.

Cost of surgical treatment for ulnar nerve entrapment in Finland, 2011-2015: a registry-based cost description study.

OBJECTIVES: The aim of this study was to evaluate the cost of surgical treatment for primary ulnar nerve entrapment (UNE) borne by the public sector in Finland. DESIGN: Registry-based cost description study. SETTING: Primary and secondary care throughout Finland. PARTICIPANTS: We identified all the patients diagnosed with primary UNE in the whole population of Finland from 2011 to 2015 from the Care Register for Health Care. From these patients, we identified those who had undergone ulnar nerve release during the year they were diagnosed or the following year. INTERVENTIONS: Open ulnar nerve release. OUTCOME MEASURES: The primary outcome measure was cost borne by the public sector in 2015 euros. The cost of surgery was based on the diagnosis-related group prices. We calculated the cost of a single visit to a primary care physician, an electroneuromyography examination, a preoperative visit to a hand surgeon and a follow-up appointment by telephone in specialised care for each patient. These unit costs were provided by the Finnish Institute for Health and Welfare and the same costs were used for each patient. We obtained the number of reimbursed sick days and the total amount reimbursed to each patient in euros within the 2 years after diagnosis from the Social Insurance Institution of Finland. RESULTS: During our study period, approximately 1786 primary UNE diagnoses were made yearly, and on average, 876 (49%) of patients received surgical treatment annually. The surgery-related cost per patient averaged at EUR 1341 (43%) and reimbursed sick leaves at EUR 952 (30%) during this period. The annual cost of surgical treatment for UNE borne by the public sector in Finland varied between EUR 3082 and EUR 3213 per patient. CONCLUSIONS: The average cost of surgical treatment for UNE in Finland was EUR 3140 per patient between 2011 and 2015.

Median and Ulnar Nerve Compressions: Simplifying Diagnostics and Surgery at the Elbow and Hand.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the anatomy of the median and ulnar nerves. 2. Perform clinical examination of the upper limb. 3. Analyze examination results to diagnose level of nerve compression. SUMMARY: Numbness and loss of strength are common complaints in the hand surgery clinic. Two nerves that are commonly entrapped (median and ulnar nerves) have several potential sites of entrapment, and in busy clinical practice, the less common sites may be overlooked, leading to wrong or missed diagnoses. This article reviews the anatomy of the median and ulnar nerves, provides tips to assist the busy clinician in diagnosis of site of entrapment(s), and discusses how to simplify surgery. The goal is to help the clinician be as efficient and accurate as possible when evaluating the patient with numbness or loss of strength in their hand.

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.

Factors influencing return to work after surgery for ulnar nerve compression at the elbow.

Ulnar nerve compression at the elbow (UNE) frequently affects people of working age. Surgically treated patients may not immediately return to work (RTW) postoperatively. In 2008, the Swedish Social Insurance Agency reformed the national insurance policy. We aimed to examine RTW postoperatively for UNE, variations among surgical methods, and potential risk factors for prolonged RTW (sick leave > 6 weeks). Surgically treated cases of UNE (n = 635) from two time periods (2004-2008 and 2009-2014) and two healthcare regions (Southern and South-eastern) were studied retrospectively regarding age, sex, comorbidities, occupation, type of surgery and time to RTW. A sub-analysis of the exact number of weeks before RTW (n = 201) revealed longer RTW for unemployed cases compared to employed cases. Prolonged RTW was seen among younger, manual workers and after transposition or revision surgery. Prolonged RTW was approximately four times more likely after transposition than after simple decompression. Comparisons before and after 2008 showed occupational differences and differences in RTW, where cases operated before 2008 more often had permanent sickness benefit, but the reform of the social insurance system did not seem to influence RTW. In conclusion, unemployment, younger age at surgery, manual labour, transposition, and revision surgery were related to prolonged RTW.

Predictive Factors Associated with the Need for Simultaneous Carpal Tunnel and Ulnar Nerve at the Elbow Releases.

INTRODUCTION: Carpal tunnel syndrome and ulnar nerve compression at the elbow (e.g., cubital tunnel syndrome) are the most common upper extremity compressive neuropa- thies treated by hand surgeons. The aim of this study was to determine demographic factors and comorbidities that can help predict those patients most likely to undergo concurrent release of both the carpal tunnel and ulnar nerve at the elbow. We hypothesized that certain comorbidities, such as diabetes, would be associated with an increased risk for the necessity of concomitant procedures. METHODS: Using Truven Marketscan® database, all patients who underwent carpal tunnel release were identified from 2010 to 2017 using Current Procedural Terminology (CPT) codes. Patients were only included if they had continuous enrollment in the database for 12 months preoperatively. Preoperative comorbidities and concurrent procedures were collected us- ing CPT and ICD-9 and 10 codes. Patients who underwent simultaneous carpal tunnel and ulnar nerve at the elbow release on the same day were compared to those patients who underwent carpal tunnel release alone. Additionally, patients who underwent either procedure initially and then went on to have the other procedure at a later date were compared. Univariate analysis and binomial logistic regression were performed to assess the contribution of patient demographics and comorbidities on the necessity of simultaneous release. RESULTS: 259,574 patients underwent carpal tunnel release surgery and were included in the study. 24,401 (7.9%) of pa- tients also underwent simultaneous ulnar nerve release at the elbow on the same day. Significant risk factors associated with the need for simultaneous release, were male gender [(Odds Ratio (OR): 2.05, Confidence Interval (CI): 2.00-2.11, p < 0.001)], chronic pain (OR: 1.78, CI: 1.68-1.87, p < 0.001), diabetes (OR: 1.29, CI: 1.25-1.33, p < 0.001), history of al- coholism (OR: 1.23, CI: 1.10-1.38, p < 0.001), chronic renal disease (OR: 1.26, CI: 1.18-1.34, p < 0.001), tobacco use (OR: 1.49, CI: 1.42-1.56, p < 0.001), and patients with congestive heart failure (OR: 1.26, CI: 1.17-1.35, p < 0.001). Patients with consumer driven health plans and high deductible health plans (HDHP) were 1.5 times more likely to have simultane- ous release compared to those with comprehensive plans (OR: 1.46, CI: 1.37-1.56, p < 0.001; OR: 1.45, CI: 1.34-1.57, p < 0.001; respectively). For necessity of subsequent carpal or ulnar nerve release after either primary procedure, patients with a minimum of 3 years enrollment in the database were analyzed. Of the 113,505 patients who underwent initial carpal tunnel release, 1,746 (1.5%) went on to undergo release of the ulnar nerve at the elbow. Of the 12,673 patients who had initial ulnar nerve releases at the elbow, 721 (5.7%) required additional release of the carpal tunnel. CONCLUSION: Identification of patient demographic factors and comorbidities that can help predict the likelihood of si- multaneous release of both the carpal tunnel and ulnar nerve at the elbow can help direct management of these patients. Combining the two procedures can help save resources, minimize patient burden, and help reduce excess health care utilization.

Surgically Treated Carpal Tunnel Syndrome and Ulnar Nerve Entrapment at the Elbow in Different Occupations and their Effect on Surgical Outcome.

OBJECTIVE: We investigated whether certain occupations were over-represented among surgically treated carpal tunnel syndrome and ulnar entrapment at the elbow, and if manual occupation affected surgical outcome. METHODS: We included 9030 patients operated for CTS and 1269 for UNE registered in the Swedish National Quality Register for Hand Surgery (HAKIR) 2010-2016. Occupational data was retrieved from Statistics Sweden. Outcome was assessed using the QuickDASH questionnaire. RESULTS: In patients operated for CTS, there were more assistant nurses, attendants/care providers/personal assistants, nannies/student assistants, carpenters/bricklayers/construction workers, cleaners, nurses, and vehicle mechanics than in the general population. In the UNE population, assistant nurses and attendants/care providers/personal assistants were over-represented. Manual workers with CTS scored the preoperative QuickDASH higher than non-manual workers. CONCLUSIONS: Manual workers are overrepresented among surgically treated CTS and UNE. Manual workers with CTS have more symptoms preoperatively than non-manual workers.

Ulnar nerve dislocation in ulnar nerve entrapment at the elbow. Influence on surgical outcome.

Our aim was to assess the incidence of symptomatic ulnar nerve dislocation and its influence on surgical outcome after primary and revision surgeries in ulnar nerve entrapment at the elbow (ulnar neuropathy at the elbow (UNE) or cubital tunnel syndrome). The influence of pre- or intra-operative ulnar nerve dislocation on postoperative outcome was assessed in 548 surgically treated cases (548 nerves) from two hand surgery departments reporting to the Swedish National Quality Registry for Hand Surgery, using QuickDASH, a patient-reported outcome measure (PROM), before surgery and at 3 and 12 months postoperatively, and a doctor-reported outcome measure (DROM), grading as "cured-improved "or "unchanged-worsened," at a median follow-up of 3.0 months [IQR, 1.5-6.0]. 109 of the 548 cases (20%) showed documented pre- or intra-operative ulnar nerve dislocation; more often found at revision (35/75, 47%) than at primary surgery (74/473, 16%) (p < 0.0001). Cases with dislocation presented higher QuickDASH scores at 12 months (p = 0.026). A linear regression model, adjusted for age and gender, predicted higher QuickDASH scores at 12 months postoperatively for cases with dislocation (unstandardized B 11.3 [95% CI 0.4-22.2], p = 0.043). DROM grading as unchanged-worsened at a median 3 months predicted worse QuickDASH scores (p < 0.0001) than in cured-improved cases at 3 (unstandardized B, 18.4 [95% CI 9.4-27.3]) and 12 months (unstandardized B, 18.1 [9.1-27.0]). Primary surgeries had better DROM grading than revision surgeries (p = 0.033; cured-improved, 75% and 63%, respectively), but QuickDASH scores did not differ. Presence of a clinically relevant ulnar nerve dislocation resulted in worse outcome, perhaps due to more extensive surgery with transposition. Nerve dislocation needs attention when treating UNE patients.

Dynamic Evaluation of Intraneural Microvascularity of the Ulnar Nerve Using Contrast-Enhanced Ultrasonography in Patients With Cubital Tunnel Syndrome.

PURPOSE: The purpose of this study was to compare the intraneural microvascular patterns of the ulnar nerve at 2 elbow flexion angles in asymptomatic volunteers and patients with cubital tunnel syndrome (CuTS) and to evaluate the effects of surgery on the microvascular pattern in patients with CuTS by using contrast-enhanced ultrasonography (CEUS). METHODS: This study included 10 elbows in 10 asymptomatic volunteers (control group) and 10 elbows in 10 patients with CuTS who underwent anterior subcutaneous transposition of the ulnar nerve (CuTS group). The CuTS group underwent clinical and electrophysiologic examinations and CEUS before surgery and at 1, 2, and 3 months after surgery. The intraneural enhancement pattern was calculated as an area under the curve (AUC) value in the entrapment site of the ulnar nerve within the cubital tunnel and in the area 1 cm proximal to the site (proximal site) at elbow flexion angles of 20° and 110°. RESULTS: Serial electrophysiologic examinations showed improvements at 1, 2, and 3 months after surgery compared with before surgery. In the control group, the AUC values of the central part of the cubital tunnel and proximal sites showed no substantial changes with the increase in elbow flexion. In the CuTS group, the AUC in the proximal site at 110° of elbow flexion was decreased compared with that at 20° of flexion before surgery. The AUC values for both the entrapment and proximal sites at 20° and 110° of elbow flexion were the most increased at 2 months after surgery compared with before surgery. CONCLUSIONS: Increased elbow flexion in patients with CuTS influences the intraneural blood flow of the ulnar nerve. Surgery for CuTS alters the intraneural blood flow. CLINICAL RELEVANCE: Quantitative evaluation of the intraneural blood flow of the ulnar nerve using CEUS may be a new supplementary diagnostic tool for CuTS and an indicator for the evaluation of postoperative recovery from nerve damage.

Risk factors and outcomes in 385 cases of ulnar nerve submuscular transposition.

Submuscular transposition (SMT) for treatment of ulnar nerve entrapment is commonly performed, however published comparisons of surgical techniques exclude a high proportion of the at-risk population encountered in real world practice. To examine the influence of risk factors on the clinical outcome following SMT we performed a retrospective review of all patients who underwent SMT, including patient self-reported outcome and Louisiana State University Medical Centre ulnar nerve grading scale. A total of 403 ulnar nerves were operated, with follow-up data available for 385 cases (359 patients). Risk factors (including smoking, diabetes, previous elbow trauma/pathology, subluxation, workers' compensation) were reported in 266 of 385 surgeries (69.09%). SMT was the primary procedure in 339 nerves (88.05%), revision procedure in 46 nerves (11.95%). At last follow up 91.05% reported symptomatic improvement. Nerve grade improvement in 71.09% of primary and 67.39% revision surgery (p = 0.605). No significant difference in improvement was identified between demographic and risk categories, except for patient reported improvement in those without peripheral neuropathy (90.59% vs 73.33%, p = 0.027), and those not improved were on average older than those improved (62.94 vs. 55.68 years, p = 0.012). Superficial infection occurred in 2.6% and there were no deep infections. Application of published exclusion criteria would have resulted in exclusion of ½-⅔ of our cohort. SMT in patients with a history of elbow trauma, diabetes, workers compensation, smoking history, nerve subluxation or revision surgery have similar outcomes compared to those without these factors, whilst improved results were observed in younger patients and those without peripheral neuropathy.

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.

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.