Safety and Outcomes of Different Surgical Techniques for Cubital Tunnel Decompression: A Systematic Review and Network Meta-analysis

Round table discussion: the management of idiopathic cubital tunnel syndrome

Idiopathic cubital tunnel syndrome is the second most common neuropathy in the upper limb. Best evidence regarding the surgical management of this condition has evolved from anterior or submuscular transposition as the former reference standard, to in situ simple release. Differences of opinion remain regarding the timing of surgery, type of surgery and adjunctive surgery. Four surgeons with Level 5 expertise were asked to answer specific questions regarding this condition.

Surgical management of cubital tunnel syndrome: A systematic review and meta-analysis of randomised trials

Background

Cubital tunnel syndrome (CUTS) is a common upper limb compression neuropathy with significant consequences when left untreated. Surgical decompression remains gold-standard treatment for moderate to severe disease, however the optimal operative technique remains unclear. This network meta-analysis (NMA) of Level I and II randomised prospective studies aims to discern superiority between open in-situ, endoscopic and anterior transposition (subcutaneous or submuscular techniques) with respect to the primary outcome of response-to-treatment and secondary outcomes which include complications, post-operative chronic pain VAS scale, return to work and re-operation.

Methods

This NMA adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. PubMed, Web of Science, Cochrane Central, Science direct and Embase were searched. The MESH database was further searched with the terms 'cubital tunnel' to improve sensitivity of the search. Data pertaining to the primary and secondary outcomes were pooled for NMA.

Results

Following abstract and full-text screening, 10 randomised prospective trials were included. There was no statistical difference in the response-to-treatment between the four studied techniques. Endoscopic decompression conferred a significantly higher complication rate compared to open decompression (Odds Ratio [OR], 4.21; 95% CI, 1.22-14.59). Endoscopic decompression had a statistically significant lower risk of post-operative chronic pain compared to open in-situ decompression (OR, 0.03, 95% CI, 0.00-0.32). There were no differences between techniques with respect to return to work or re-operation rates.

Conclusion

Response-to-treatment was similar between the four operative techniques for CUTS. Endoscopic decompression was found to be more hazardous when compared to open-in situ decompression but conferred significantly less post-operative chronic pain. There was significant heterogeneity in reported outcomes between the included articles. The authors suggest conducting more high-quality research with standardised outcome reporting to facilitate comparison.

Level of evidence ii

Systematic Review and Meta-analysis of Randomised Prospective Trials- Therapeutic study.

Serial electrodiagnostic testing: Utility and indications in adult neurological disorders

Although existing guidelines address electrodiagnostic (EDX) testing in identifying neuromuscular conditions, guidance regarding the uses and limitations of serial (or repeat) EDX testing is limited. By assessing neurophysiological change longitudinally across time, serial electrodiagnosis can clarify a diagnosis and potentially provide valuable prognostic information. This monograph presents four broad indications for serial electrodiagnosis in adult peripheral neurological disorders. First, where clinical change has raised suspicion for a new or ongoing lesion, EDX reassessment for spatial spread of abnormality, involvement of previously normal muscle or nerve, and/or evolving pathophysiology can clarify a diagnosis. Second, where diagnosis of a progressive neuromuscular condition is uncertain, electrophysiological data from a second time point can confirm or refute suspicion. Third, to establish prognosis after a static nerve injury, a repeat study can assess the presence and extent of reinnervation. Finally, faced with a limited initial study (as when complicated by patient or environmental factors), a repeat EDX study can supplement missing or limited data to provide needed clarity. Repeat EDX studies carry certain limitations, however, such as with prognostication in the setting of remote or chronic lesions, sensory predominant fascicular injury, or mild axonal injury. Nevertheless, serial electrodiagnosis remains a valuable and underused tool in the diagnostic and prognostic evaluation of neuromuscular conditions.

Subcutaneous Anterior Transposition With Modified Procedures to Prevent Recurrence Associated With the Transposed Ulnar Nerve

Subcutaneous anterior transposition of the ulnar nerve is a common surgical treatment for cubital tunnel syndrome. However, there are surgical failures associated with the new compressive sites at the edge of flexor carpi ulnaris (FCU) and resubluxation posterior to the medial epicondyle of the transposed nerve. To reduce the muscle volume at the edge of FCU, we approach the ulnar nerve by dividing the muscle belly of the FCU humeral heads. This procedure can reduce repeated traction forces on the transposed nerve at the edge of the FCU. To keep the transposed ulnar nerve anteriorly, we use a fat flap including the membranous superficial fascia. This flap can softly stabilize the ulnar nerve and act as a pliable cover to prevent perineural scarring or further constriction around the flap. Ninety-three elbows in 90 patients who had undergone this procedure for cubital tunnel syndrome were evaluated. According to Messina's criteria, the numbers of patients showing excellent, good, fair, and poor recovery were 41 (44%), 47 (51%), 5 (5%), and 0 (0%), respectively. Most patients experience resolution of symptoms and good functional outcomes. None of the patients suffered recurrence, infection, or nerve injury.

The Unpredictable Ulnar Nerve-Ulnar Nerve Entrapment from Anatomical, Pathophysiological, and Biopsychosocial Aspects

Peripheral nerves consist of delicate structures, including a rich microvascular system, that protect and nourish axons and associated Schwann cells. Nerves are sensitive to internal and external trauma, such as compression and stretching. Ulnar nerve entrapment, the second most prevalent nerve entrapment disorder after carpal tunnel syndrome, appears frequently at the elbow. Although often idiopathic, known risk factors, including obesity, smoking, diabetes, and vibration exposure, occur. It exists in all adult ages (mean age 40-50 years), but seldom affects individuals in their adolescence or younger. The patient population is heterogeneous with great co-morbidity, including other nerve entrapment disorders. Typical early symptoms are paresthesia and numbness in the ulnar fingers, followed by decreased sensory function and muscle weakness. Pre- and postoperative neuropathic pain is relatively common, independent of other symptom severity, with a risk for serious consequences. A multimodal treatment strategy is necessary. Mild to moderate symptoms are usually treated conservatively, while surgery is an option when conservative treatment fails or in severe cases. The decision to perform surgery might be difficult, and the outcome is unpredictable with the risk of complications. There is no consensus on the choice of surgical method, but simple decompression is relatively effective with a lower complication rate than transposition.

Patient-reported outcomes after free muscle flap coverage for therapy-resistant neuropathic pain from the ulnar nerve

Extensive microsurgical neurolysis followed by free gracilis muscle flap coverage can be performed as a last resort for patients with persistent neuropathic pain of the ulnar nerve. All patients who had this surgery between 2015 and 2021 were identified. Data were collected from the medical records of 21 patients and patient-reported outcomes were collected from 18 patients, with a minimum follow-up of 12 months. The median visual analogue pain score decreased significantly 8 months postoperatively from 8.0 to 6.0 and stabilized to 5.4 at the 3-year follow-up. Health-related quality-of-life scores remained diminished compared to normative data. In the treatment of therapy-resistant neuropathic pain of the ulnar nerve, extensive neurolysis with a subsequent free gracilis muscle flap coverage shows a promising reduction of pain that persists at long-term follow-up.Level of evidence: IV.

[Role and place of ipidacrine in the therapy of diseases of the peripheral nervous system. The resolution of the expert council]

The resolution of the expert council is devoted to discussing aspects of the use of ipidacrine for the treatment of mononeuropathies, polyneuropathies and radiculopathies of various etiologies. Specialists prepared recommendations for ipidacrine's application in treating peripheral nervous system disorders.

Ulnar neuropathy

Ulnar neuropathy at the elbow is the second most common compressive neuropathy. Less common, although similarly disabling, are ulnar neuropathies above the elbow, at the forearm, and the wrist, which can present with different combinations of intrinsic hand muscle weakness and sensory loss. Electrodiagnostic studies are moderately sensitive in diagnosing ulnar neuropathy, although their ability to localize the site of nerve injury is often limited. Nerve imaging with ultrasound can provide greater localization of ulnar injury and identification of specific anatomical pathology causing nerve entrapment. Specifically, imaging can now reliably distinguish ulnar nerve entrapment under the humero-ulnar arcade (cubital tunnel) from nerve injury at the retro-epicondylar groove. Both these pathologies have historically been diagnosed as either "ulnar neuropathy at the elbow," which is non-specific, or "cubital tunnel syndrome," which is often erroneous. Natural history studies are few and limited, although many cases of mild-moderate ulnar neuropathy at the elbow appear to remit spontaneously. Conservative management, perineural steroid injections, and surgical release have all been studied in treating ulnar neuropathy at the elbow. Despite this, questions remain about the most appropriate management for many patients, which is reflected in the absence of management guidelines.

Comparison of in-situ release and submuscular anterior transposition of ulnar nerve for refractory cubital tunnel syndrome, previously treated with subfascial anterior transfer-A retrospective study of 24 cases

BACKGROUND

Although cubital tunnel syndrome is the second most common type of compressive neuropathy in the upper extremities, the indication and optimal surgical method for recurrent or refractory cubital tunnel syndrome remains controversial. This study evaluates the functional outcomes of revision surgery for cubital tunnel syndrome.

MATERIAL & METHODS

This study was a retrospective observational multicenter single-institution study including 660 patients who underwent surgery for cubital tunnel syndrome from 2010 to 2019. Among the 660 patients, 42(6.4%) received revision surgery due to remaining or recurrent symptoms confirmed with electromyography(EMG). After excluding those with concurrent elbow fracture, dislocation, osteoarthritis and wound infection, a total of 24 patients were included in the study. The patients were evaluated of disease severity, revision surgical method, time interval to recurrence, underlying diseases and postoperative functional outcomes.

RESULTS

All patients received ulnar nerve subfascial anterior transposition for the initial cubital tunnel syndrome surgery. Among the 24 patients (3.7%) who received revision surgery, nine received in situ neurolysis, 12 received submuscular transposition, and three received subcutaneous transfer. 21 patients (88%) reported improved mean VAS score of 4.3, while three patients complained of remaining symptoms that did not improve even after revision surgery. The patients with remaining symptoms all had underlying diabetes mellitus and were treated with subcutaneous transfer. The difference of surgical outcomes between the in situ neurolysis group and the nerve transfer groups were non-significant (p = 0.23). The most common cause of recurrent or persistent symptoms was adhesion and fibrosis at sling area. The mean follow up period before revision surgery was 26.3 months and postoperative follow up period after revision surgery was 8.5 months.

CONCLUSION

The outcomes of this study imply that in-situ neurolysis may be as effective as anterior submuscular transfer of ulnar nerve for refractory cubital tunnel syndrome after anterior subfascial transfer.

Preoperative electrodiagnostic studies and postoperative outcomes for ulnar mononeuropathy at the elbow: A systematic review

OBJECTIVE

To analyze the association between preoperative electrodiagnostic (EDX) studies and postoperative pain and functional outcomes following ulnar nerve decompression and/or transposition for ulnar neuropathy at the elbow (UNE).

LITERATURE SURVEY

Protocol was submitted and database search was conducted by an experienced librarian of all available studies in the English language from 1990 to June 8, 2022. Databases included Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, and Scopus.

METHODOLOGY

Inclusion criteria consisted of randomized controlled trials, prospective and retrospective longitudinal studies, and studies involving adults ≥18 years of age who underwent ulnar nerve decompression and/or transposition for UNE. Study quality and risk of bias were assessed using the National Heart, Lung, and Blood Institute (NHLBI) Study Quality of Assessment Tool. Certainty in evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. A meta-analysis was not performed.

SYNTHESIS

A total of 289 studies were screened, and 8 retrospective cohort studies met inclusion criteria comprising 762 patients. A decreased or absent preoperative sensory nerve action potential amplitude (SNAP) showed significance with worse postoperative outcomes. The presence of preoperative conduction block showed significance in higher quality studies. There was limited evidence for slow preoperative motor conduction velocities or preoperative electromyography (EMG) abnormalities and postoperative outcomes. Overall quality assessment demonstrated that two studies had "good," four "fair," and two "poor" quality of evidence. Certainty in evidence was "low" due to risk of bias.

CONCLUSIONS

A decreased or absent preoperative ulnar SNAP may predict worse postoperative outcomes. Per higher quality studies, preoperative conduction block at the elbow may also predict worse postoperative outcomes. Careful interpretation is required with a full understanding of the limited evidence, risk of bias, and low certainty in evidence to support the use of preoperative EDX to predict postoperative outcomes in UNE.

Form and Function: Technique for Free Functional Gracilis Harvest With Greater Saphenous Vein for Large Skin Paddle

Free functional gracilis transfer is a technique for restoration of upper extremity function following brachial plexus injury, as well as muscle loss from traumatic, oncologic, and congenital causes. However, when used for the latter applications, a functional muscle as well as large skin paddle can be required. Historically, skin paddle size was limited by venous outflow of the gracilis flap, using 1 or 2 venae comitantes, and large unreliable skin paddles resulting in partial necrosis. Therefore, to restore form and function, we herein present a technique of free functional gracilis muscle harvest with inclusion of adjacent greater saphenous vein for inclusion of a large skin paddle with 2 venous drainage systems.

Mechanomyography as a Surgical Adjunct for Treatment of Chronic Entrapment Neuropathy: A Case Series

BACKGROUND

Chronic entrapment neuropathy results in a clinical syndrome ranging from mild pain to debilitating atrophy. There remains a lack of objective metrics that quantify nerve dysfunction and guide surgical decision-making. Mechanomyography (MMG) reflects mechanical motor activity after stimulation of neuromuscular tissue and may indicate underlying nerve dysfunction.

OBJECTIVE

To evaluate the role of MMG as a surgical adjunct in treating chronic entrapment neuropathies.

METHODS

Patients 18 years or older with cubital tunnel syndrome (n = 8) and common peroneal neuropathy (n = 15) were enrolled. Surgical decompression of entrapped nerves was performed with intraoperative MMG of the hypothenar and tibialis anterior muscles. MMG stimulus thresholds (MMG-st) were correlated with compound muscle action potential (CMAP), motor nerve conduction velocity, baseline functional status, and clinical outcomes.

RESULTS

After nerve decompression, MMG-st significantly reduced, the mean reduction of 0.5 mA (95% CI: 0.3-0.7, P < .001). On bivariate analysis, MMG-st exhibited significant negative correlation with common peroneal nerve CMAP ( P < .05), but no association with ulnar nerve CMAP and motor nerve conduction velocity. On preoperative electrodiagnosis, 60% of nerves had axonal loss and 40% had conduction block. The MMG-st was higher in the nerves with axonal loss as compared with the nerves with conduction block. MMG-st was negatively correlated with preoperative hand strength (grip/pinch) and foot-dorsiflexion/toe-extension strength ( P < .05). At the final visit, MMG-st significantly correlated with pain, PROMIS-10 physical function, and Oswestry Disability Index ( P < .05).

CONCLUSION

MMG-st may serve as a surgical adjunct indicating axonal integrity in chronic entrapment neuropathies which may aid in clinical decision-making and prognostication of functional outcomes.

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.

Modern Treatment of Cubital Tunnel Syndrome: Evidence and Controversy

Cubital tunnel syndrome is the second most common peripheral mononeuropathy in the upper extremity. However, the diagnosis and treatment of cubital tunnel syndrome remains controversial without a standard algorithm. Although diagnosis can often be made from the patient's history and physical examination alone, electrodiagnostic studies, ultrasound, computed tomography (CT), and magnetic resonance image (MRI) can also be useful in diagnosing the disease and selecting the most appropriate treatment option. Treatment options include conservative nonoperative techniques as well as various surgical options, including in situ decompression with or without transposition, medial epicondylectomy, and nerve transfer in advanced disease. The purpose of this review is to summarize the most up-to-date literature regarding cubital tunnel syndrome and propose a treatment algorithm to provide clarity about the challenges of treating this complex patient population.

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.

Factors Influencing Patient Experience After Cubital Tunnel Syndrome Surgery

PURPOSE

The purpose of this study was to use qualitative methodology to better understand patient experiences after cubital tunnel surgery, with the goal of identifying areas of improvement in delivery of care.

METHODS

Patients who underwent surgery (in situ decompression or anterior transposition) for cubital tunnel syndrome within the last 12 months, which was performed by one of three fellowship-trained hand surgeons, were identified. Participants were invited to an interview regarding "their experiences with ulnar nerve surgery." An interview guide with semistructured, open-ended questions regarding the decision for surgery, treatment goals, and the recovery process was used. Interim data analyses were conducted to assess emerging themes, and interviews were continued until thematic saturation was achieved.

RESULTS

Seventeen participants completed interviews; the mean age of study participants was 57 years, and 71% were women. The mean time between surgery and the interview was 6 months. Participants identified the following two key areas that could improve their surgical experience: (1) the need for detailed preoperative education about the surgery and recovery process, (2) and the importance of discussing treatment goals and expectations. Participants suggested providing both written and online resources to patients, including specific details about incision size and recovery process in education materials, and setting expectations for symptom resolution.

CONCLUSIONS

Although the overall patient experience after cubital tunnel surgery was positive, participants noted that there is a need for providing improved educational resources and counseling before surgery.

CLINICAL RELEVANCE

Addressing education and counseling needs before cubital tunnel surgery will help surgeons to improve delivery of care.

A complete analysis of the surgical treatment for cubital tunnel syndrome: an umbrella review

BACKGROUND

Numerous original studies have been presented regarding various surgical treatments for cubital tunnel syndrome (CubTS). The results of these analyses regarding the different surgical treatments for CubTS frequently differ and, in some cases, contradict each other, creating confusion. Therefore, our umbrella review aimed to summarize the evidence from meta-analyses and systematic reviews regarding the surgical treatments of CubTS, and along with the new, more detailed outcomes, provide an evidence-based tool for surgeons performing these procedures.

MATERIALS AND METHODS

To perform this umbrella review, a systematic search was conducted for meta-analyses investigating CubTS in PubMed, Scopus, Embase, Web of Science, Google Scholar, Cochrane Library, BIOSIS, and EBSCO medical databases.

RESULTS

Detailed comparison of surgical outcomes, such as clinical improvement, complications, or reoperation rates, of different treatment methods for CubTS was performed. New risk ratios in all categories were established based on all of the primary studies available in the literature.

DISCUSSION

The goal of the present umbrella review was to gather and summarize all data about the surgical treatments for CubTS in the available literature and provide new outcomes and an evidence-based tool for surgeons performing these procedures. Each comparison of the surgical techniques has been discussed, and the present study's results were compared with the outcomes of the previous studies.

Does the Surgical Assistant Influence Perioperative Outcomes Surrounding Cubital Tunnel Surgery?

Background: Ulnar neuropathy at the elbow is the second most common upper extremity compressive neuropathy and surgical treatment often involves surgical trainee involvement. The primary aim of this study is to determine the effect of trainees and surgical assistants on outcomes surrounding cubital tunnel surgery. Methods: This retrospective study included 274 patients with cubital tunnel syndrome who underwent primary cubital tunnel surgery at two academic medical centres between 1 June 2015 and 1 March 2020. The patients were divided into four main cohorts based on primary surgical assistant: physician associates (PA, n = 38), orthopaedic or plastic surgery residents (n = 91), hand surgery fellows (n = 132), or both residents and fellows (n = 13). Exclusion criteria included patient age <18 years, revision surgery as the index procedure, prior traumatic ulnar nerve injury and concurrent procedures not related to cubital tunnel surgery. Demographics, clinical variables and perioperative findings were collected through chart reviews. Univariate and bivariate analyses were performed, and p < 0.05 was considered significant. Results: Patients in all cohorts had similar demographic and clinical characteristics. There was a significantly higher rate of subcutaneous transposition in the PA cohort (39.5% PA vs. 13.2% Resident vs. 19.7% Fellow vs. 15.4% Resident + Fellow). Presence of surgical assistants and trainees had no association with length of surgery, complications and reoperation rates. Although male sex and ulnar nerve transposition were associated with longer operative times, no explanatory variables were associated with complications or reoperation rates. Conclusions: Surgical trainee involvement in cubital tunnel surgery is safe and has no effect on operative time, complications or reoperation rates. Understanding the role of trainees and measuring the effect of graduated responsibility in surgery is important for medical training and safe patient care. Level of Evidence: Level III (Therapeutic).

Percutaneous ultrasound-guided ulnar nerve release technique compared to open technique: A cadaveric study

Objectives: To evaluate the outcomes of a novel percutaneous ultrasound-guided technique for release of ulnar nerve entrapment at the elbow when compared to standard open release Methods: One single surgeon performed an ultrasound-guided percutaneous release of the cubital tunnel on a group of five cadaveric elbows and open release on five others. All procedures were timed, and incision lengths were recorded. Meticulous anatomic dissection was then performed to assess the complete release of the carpal tunnel and iatrogenic injuries. Results: No significant difference was found between the two groups in terms of complete release and iatrogenic injury, whereas Operative time was significantly shorter for the US-guided technique. Incomplete releases of the nerve were found only during the first two trials in each group, while the third, fourth, and fifth trials showed a complete ulnar nerve release in both series, highlighting a fast learning curve for both techniques. All of this through a significantly smaller incision in the US-guided technique. Conclusions: This study highlights the similar effects of these two techniques in terms of complete release of the ulnar nerve, with no clear superiority of one over the other in terms of morbidity rate. Both have a fast learning curve for an ultrasound-trained surgeon, with the US-guided technique being a less traumatic and quicker alternative procedure.

A Comprehensive Review of Cubital Tunnel Syndrome

Cubital Tunnel Syndrome (CuTS) is the compression of the ulnar nerve as it courses through the cubital tunnel near the elbow at the location colloquially referred to as the "funny bone". CuTS is the most commonly diagnosed mononeuropathy after carpal tunnel syndrome. Cubital tunnel syndrome can manifest as numbness, tingling, or pain in the ring/small fingers and dorsoulnar hand. Repetitive pressure, stretching, flexion, or trauma of the elbow joint are known causes of CuTS. Chronic ulnar nerve compression and CuTS, when left untreated, can lead to atrophy of the first dorsal interosseus muscle and affect one's quality of life to the point that they are no longer able to participate in daily activities involving fine motor function. It is estimated that up to 5.9% of the general population have had symptoms of CuTS. CuTS is underdiagnosed due to lack of seeking of treatment for symptoms. Compression or damage to the ulnar nerve is the main cause of symptoms experienced by an individual with CuTS. Repetitive elbow pressure or a history or elbow joint trauma or injury are additional known causes that can lead to CuTS. Common presentations of CuTS include paresthesia, clumsiness of the hand, hand atrophy and weakness. The earliest sign of CuTS is most commonly numbness and tingling of the ring and 5th finger. Older patients tend to present with motor symptoms of chronic onset; younger patients tend to have more acute symptoms. Pain and point tenderness at the medial elbow may also be seen. CuTS lacks universally agreed upon diagnostic and treatment algorithms. CuTS can be diagnosed by physical exam using Tinel's sign, flexion-compression tests, palpating the ulnar nerve for thickening presence of local tenderness along the nerve. Ultrasound and nerve conduction studies may be used in combination with physical exam for diagnosis. Conservative treatment for CuTS is almost always pursued before surgical treatment and includes elbow splints, braces, and night-gliding exercises. Surgical treatment may be pursued in severe CuTS refractory to conservative treatment. Surgical options include open and endoscopic in-situ decompression, medial epicondylectomy, and anterior transposition of the ulnar nerve. CuTS is a prevalent disease that, if left untreated, can significantly alter an individual's quality of life. Therefore, an accurate diagnosis and appropriate treatment is paramount in reducing further damage and preventing worsening or future symptoms.

Utility of carpal tunnel release and ulnar decompression in CMT1A and HNPP

INTRODUCTION/AIMS

Carpal and cubital tunnel syndrome (CTS, CuTS) are common among patients with hereditary neuropathy with liability to pressure-palsies (HNPP) and Charcot-Marie-Tooth-1A (CMT1A), and may impact quality of life. We aimed to evaluate the utility of nerve decompression surgeries in these patients.

METHODS

Medical records were reviewed for patients with PMP22 mutation confirmed in Mayo Clinic laboratories from January 1999 to December 2020, who had CTS and CuTS and underwent surgical decompression.

RESULTS

CTS occurred in 53.3% of HNPP and 11.5% of CMT1A, while CuTS was present in 43.3% of HNPP and 5.8% of CMT1A patients. CTS decompression occurred in 10-HNPP and 5-CMT1A patients, and CuTS decompression with/without transposition was performed in 5-HNPP and 1-CMT1A patients. In HNPP, electrodiagnostic studies identified median neuropathy at the wrist in 9/10 patients and ultrasound showed focal enlargements at carpal and cubital tunnels. In CMT1A, median and ulnar sensory responses were all absent, and the nerves were diffusely enlarged. After CTS surgery, pain, sensory loss, and strength improved in 4/5 CMT1A, and 6/10 HNPP patients. Of clinical, electrophysiologic and ultrasound findings, only activity-provoked features significantly correlated with CTS surgical benefit in HNPP patients (odds ratio=117.0:95% CI 1.94>999.99, p=0.01). One CMT1A and one HNPP patient improved with CuTS surgery while 2 HNPP patients worsened.

DISCUSSION

CTS symptom improvement post-surgery can be seen in CMT1A and (less frequent) in HNPP patients. CuTS surgery commonly worsened course in HNPP. Activity-provoked symptoms in HNPP best informed benefits from CTS surgery.

Preoperative Electrophysiology in Patients With Ulnar Nerve Entrapment at the Elbow-Prediction of Surgical Outcome and Influence of Age, Sex and Diabetes

The impact of preoperative electrophysiology on outcome of surgical treatment in ulnar nerve entrapment at the elbow (UNE) is not clarified. Our aim was to evaluate influence of preoperative electrophysiologic grading on outcome and analyse how age, sex, and in particular diabetes affect such grading. Electrophysiologic protocols for 406 UNE cases, surgically treated at two hand surgery units reporting to the Swedish National Quality Register for Hand Surgery (HAKIR; 2010-2016), were retrospectively assessed, and graded as normal, reduced conduction velocity, conduction block or axonal degeneration. Outcome of surgery after primary and revision surgery was evaluated using QuickDASH and a doctor reported outcome measure (DROM) grading. No differences in QuickDASH or DROM were found between the four groups with different electrophysiologic grading preoperatively, or at three and 12 months or at follow up, respectively. When dichotomizing the electrophysiologic grading into normal and pathologic electrophysiology, cases with normal electrophysiology had worse QuickDASH than cases with pathologic electrophysiology preoperatively (p=0.046). Presence of a conduction block or axonal degeneration indicated a worse outcome by DROM grading (p=0.011). Primary surgeries had electrophysiologic more pronounced nerve pathology compared to revision surgeries (p=0.017). Cases of older age, men, and those with diabetes had more severe electrophysiologic nerve affection (p&lt;0.0001). In the linear regression analysis, increasing age (unstandardized B=0.03, 95% CI 0.02-0.04; p&lt;0.0001) and presence of diabetes (unstandardized B=0.60, 95% CI 0.25-0.95; p=0.001) were associated with a higher risk of a worse electrophysiologic classification. Female sex was associated with a better electrophysiologic grading (unstandardized B=-0.51, 95% CI -0.75- -0.27; p&lt;0.0001). We conclude that older age, male sex, and concomitant diabetes are associated with more severe preoperative electrophysiologic nerve affection. Preoperative electrophysiologic grade of ulnar nerve affection may influence surgical outcome.

Outcome of Simple Decompression of Primary Cubital Tunnel Syndrome Based on Patient-Reported Outcome Measurements

PURPOSE

To evaluate the patient-reported outcome measures of patients with primary cubital tunnel syndrome and to assess whether they are affected by preoperative symptom severity.

METHODS

Patients who underwent simple decompression for primary cubital tunnel syndrome were selected from a prospectively maintained database. Outcome measurements consisted of the Boston Carpal Tunnel Questionnaire at intake and at 3 and 6 months after surgery. Also, 6 months after surgery, the patients received a question about their satisfaction with the treatment result. To determine a possible influence of preoperative symptom severity on postoperative outcomes, the sample was divided into quartiles based on symptom severity at intake.

RESULTS

One hundred and forty-five patients were included in the final analysis. On average, all patients improved on the Boston Carpal Tunnel Questionnaire. The subgroup of patients with the mildest symptoms at intake did not improve significantly on symptom severity but did improve significantly on their functional status. In addition, the patients with the most severe symptoms at intake did improve on both aspects. Moreover, no difference in satisfaction with treatment result between the severity of symptoms at intake was found.

CONCLUSIONS

The patients with the mildest symptoms at intake may not improve on symptom severity, but they do improve on functional status after simple decompression for cubital tunnel syndrome. In addition, patients with the most severe symptoms at intake do improve on both symptom severity and functional status. Moreover, all patients reported to be equally satisfied with the treatment result, which suggests that satisfaction is not dependent on the symptom severity at intake. Even those patients with both the mildest symptoms before surgery and the least improvement still seem to benefit from simple decompression.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Angiosomes of the Ulnar Nerve at the Elbow: A Cadaver Trial Using Contrast-Enhanced Ultrasound

Three major arteries supplying the ulnar nerve in the cubital tunnel are commonly known. However, their vascular territories (angiosomes) have not been described yet. Contrast-enhanced ultrasound was used to identify the angiosomes of posterior ulnar recurrent artery, inferior ulnar collateral artery and superior ulnar collateral artery in 20 fresh, non-frozen human body donors. The arteries were cannulated, and physiologic blood flow was simulated. Contrast agent was applied in each vessel in a randomized sequence, and the length of the contrast-enhancing ulnar nerve segment was measured by a radiologist blinded to the sequence. The angiosome of the posterior ulnar recurrent artery overlaps both other angiosomes. It fully covers the cubital tunnel in 63.6% of specimens. In addition, collateral flow via nerve and muscle branches of the arterial anastomotic network around the elbow (rete articulare cubiti) partly maintains the intra-neural blood flow in the absence of a vascular pedicle. The posterior ulnar recurrent artery is the dominant nutrient vessel of the ulnar nerve in the cubital tunnel. A potential watershed zone exists proximal to the Osborne ligament. Knowledge of these angiosomes may advance surgery of the ulnar nerve in the cubital tunnel.

Diffusion tensor imaging in cubital tunnel syndrome

Cubital tunnel syndrome (CuTS) is the 2nd most common compressive neuropathy. To improve both diagnosis and the selection of patients for surgery, there is a pressing need to develop a reliable and objective test of ulnar nerve 'health'. Diffusion tensor imaging (DTI) characterises tissue microstructure and may identify differences in the normal ulnar from those affected by CuTS. The aim of this study was to compare the DTI metrics from the ulnar nerves of healthy (asymptomatic) adults and patients with CuTS awaiting surgery. DTI was acquired at 3.0 T using single-shot echo-planar imaging (55 axial slices, 3 mm thick, 1.5 mm2 in-plane) with 30 diffusion sensitising gradient directions, a b-value of 800 s/mm2 and 4 signal averages. The sequence was repeated with the phase-encoding direction reversed. Data were combined and corrected using the FMRIB Software Library (FSL) and reconstructed using generalized q-sampling imaging in DSI Studio. Throughout the length of the ulnar nerve, the fractional anisotropy (FA), quantitative anisotropy (QA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were extracted, then compared using mixed-effects linear regression. Thirteen healthy controls (8 males, 5 females) and 8 patients with CuTS (6 males, 2 females) completed the study. Throughout the length of the ulnar nerve, diffusion was more isotropic in patients with CuTS. Overall, patients with CuTS had a 6% lower FA than controls, with the largest difference observed proximal to the cubital tunnel (mean difference 0.087 [95% CI 0.035, 0.141]). Patients with CuTS also had a higher RD than controls, with the largest disparity observed within the forearm (mean difference 0.252 × 10-4 mm2/s [95% CI 0.085 × 10-4, 0.419 × 10-4]). There were no significant differences between patients and controls in QA, MD or AD. Throughout the length of the ulnar nerve, the fractional anisotropy and radial diffusivity in patients with CuTS are different to healthy controls. These findings suggest that DTI may provide an objective assessment of the ulnar nerve and potentially, improve the management of CuTS.

Ulnar Neuropathy at the Elbow: From Ultrasound Scanning to Treatment

Ulnar neuropathy at the elbow (UNE) is commonly encountered in clinical practice. It results from either static or dynamic compression of the ulnar nerve. While the retroepicondylar groove and its surrounding structures are quite superficial, the use of ultrasound (US) imaging is associated with the following advantages: (1) an excellent spatial resolution allows a detailed morphological assessment of the ulnar nerve and adjacent structures, (2) dynamic imaging represents the gold standard for assessing the ulnar nerve stability in the retroepicondylar groove during flexion/extension, and (3) US guidance bears the capability of increasing the accuracy and safety of injections. This review aims to illustrate the ulnar nerve's detailed anatomy at the elbow using cadaveric images to understand better both static and dynamic imaging of the ulnar nerve around the elbow. Pathologies covering ulnar nerve instability, idiopathic cubital tunnel syndrome, space-occupying lesions (e.g., ganglion, heterotopic ossification, aberrant veins, and anconeus epitrochlearis muscle) are presented. Additionally, the authors also exemplify the scientific evidence from the literature supporting the proposition that US guidance is beneficial in injection therapy of UNE. The non-surgical management description covers activity modifications, splinting, neuromobilization/gliding exercise, and physical agents. In the operative treatment description, an emphasis is put on two commonly used approaches-in situ decompression and anterior transpositions.