[Combined use of biomaterials and revascularisation in autoplasty of ulnar nerve]. / Kombinirovannoe primenenie biomaterialov i revaskulyarizatsii pri autoplastike loktevogo nerva.

Surgical treatment of peripheral nerve injuries is effective in only 50% of cases. This is primarily due to the significant extent of the diastasis between the fragments of the damaged nerve, in which autoplasty has to be performed. The drawbacks of this technique are the formation of scar tissue, possible necrotisation of the autograft, mismatch of the donor and recipient nerve diameters. In order to overcome these drawbacks and improve the efficiency of surgical intervention, the study presents a clinical case of successful multifascicular ulnar nerve autoplasty with the use of domestic biodegradable biomaterials SpheroGel and ElastoPob, revascularization of the autograft with a connective tissue flap on a vascular pedicle. A persistent regression of local pain syndrome was observed in the early postoperative period. The effectiveness of the performed surgical intervention was confirmed by ultrasound examination: there was no evidence of neuroma in the area of the operation, regeneration of nerve bundles was noted at the site of stitching. Positive dynamics was observed in the results of VAS, DN4, DASH questionnaires.

Inflammatory Pseudotumor of the Ulnar Nerve Mimicking a Malignant Peripheral Nerve Sheath Tumor: A Radiologic Puzzle.

Inflammatory pseudotumor (IPT) of a peripheral nerve is a rare non-neoplastic tumefactive inflammatory condition, often mimicking malignancy. The etiology of this condition is still unknown. Clinically and radiologically, the lesion can mimic a malignant tumor. This case report represents, as far as we know, the first publication describing the ultrasonography findings and the results of advanced dynamic contrast-enhanced magnetic resonance imaging (MRI) and diffusion-weighted MRI of IPT in a peripheral nerve. Suspicion of this entity on imaging can speed up the definitive diagnosis and potentially avoid overly radical treatment.

Excision of large median and ulnar nerve schwannomas: a case series.

OBJECTIVE: Schwannomas are benign, slow-growing tumors originating from Schwann cells in peripheral nerves, commonly affecting the median and ulnar nerves in the forearm and wrist. Surgical excision is the gold standard treatment. This study presents our treatment strategies and outcomes for large-sized ulnar and median nerve schwannomas at the forearm and wrist level. METHODS: From 2012 to 2023, we enrolled 15 patients with schwannomas over 2 cm in size in the median or ulnar nerve at the forearm and wrist. The study included 12 patients with median nerve schwannomas (mean age: 61 years) and 3 with ulnar nerve schwannomas (mean age: 68 years), with a mean follow-up of 26.9 months. RESULTS: After surgery, all patients with median nerve schwannomas experienced mild, transient numbness affecting fewer than two digits, resolving within six months without motor deficits. Ulnar nerve schwannoma excision caused mild numbness in two patients, also resolving within six months, but all three developed ulnar claw hand deformity, which persisted but improved at the last follow-up. Despite this, patients were satisfied with the surgery due to relief from severe tingling pain. CONCLUSIONS: Schwannomas of the median, ulnar, and other peripheral nerves should be removed by carefully dissecting the connecting nerve fascicles to avoid injury to healthy ones. Sensory deficits may occur but are unlikely to significantly impact quality of life. However, in motor-dominant nerves like the ulnar nerve, there is a risk of significant motor deficits that could affect hand function, though not completely. Therefore, thorough preoperative discussion and consideration of interfascicular nerve grafting are essential.

Evaluation of Neuromuscular Blockade: A Comparative Study of TOF-Cuff® on the Lower Leg and TOF-Scan® on the Ulnar Nerve During Mivacurium Anesthesia.

BACKGROUND To evaluate neuromuscular monitoring during anesthesia with mivacurium, this study assessed the correlation between measurements of TOF-Cuff® placed on the lower leg and stimulating the tibial nerve and TOF-Scan® values from the adductor pollicis muscle. Additionally, systolic (SBP) and diastolic (DBO) blood pressure measured in both locations were compared. MATERIAL AND METHODS Twenty-six patients participated in this observational clinical trial. The TOF-Cuff® was placed on the lower leg and the TOF-Scan® was placed on the thumb. Train-of-four (TOF) values were recorded simultaneously by both devices at 30-second intervals before intubation. Measurements continued every 5 minutes until extubation. Bland-Altman analyses compared TOF values obtained from the 2 devices. RESULTS Time to onset and relaxation time did not differ significantly; the number of patients presenting a lack of blockade despite TOF=0 was also concordant. The time from the last dose of mivacurium to TOF ratio >90 was shorter on the leg than on hand (median 20 [5-28, 0-65] min vs 30 [20-35, 0-60] min, p=0.025). The median (range, interquartile range) difference between measurements was: 11.6 (-41 to 45, 2-19) for SBP and -8 (-28 to 26, -15 to -4) for DBP at baseline (p=0.0495); 5 (-53 to 55, -2 to 9) for SBP and -11 (-45 to 29, -19 to -5) (p=0.0017) for DBP during the blockade. CONCLUSIONS Time-to-onset and SBP are comparable between these 2 methods, in contrast to time-to-recovery and diastolic blood pressure, and this should be considered in case of the inability to apply the TOF-Cuff on the leg.

Symptomatic Idiopathic Ulnar Nerve Instability in the Elbow Diagnostic Considerations and 1-Year Outcomes After Anterior Transposition of Ulnar Nerve.

BACKGROUND: Symptomatic idiopathic ulnar nerve instability (IUNI) in the elbow is an uncommon condition characterized by symptoms of ulnar neuritis resulting from frictional injury to the ulnar nerve from repetitive subluxation out of the cubital tunnel. This study reports the 1-year clinical outcomes after treatment of IUNI with anterior transposition of the ulnar nerve. METHODS: This is a retrospective case study of five patients. Ulnar nerve instability was diagnosed clinically based on the presence of ulnar neuritis symptoms in combination with a positive "ulnar nerve push past" test. Electromyography (EMG) was performed on all patients. After failure of nonsurgical treatment, five patients underwent anterior subcutaneous transposition of the ulnar nerve at the elbow. Clinical outcome scores and time to resolution of symptoms were recorded at a minimum follow-up of 12 months. RESULTS: The mean age of the patients at the time of surgery was 37.8 years (range: 18 to 57 years). The mean duration of symptoms prior to surgery was 15.7 ± 4.9 months. All five patients reported neuritis symptoms in the distribution of ulnar nerve in the hand and had ulnar nerve instability in the cubital tunnel on clinical examination. All patients were symptom free within 6 months after anterior transposition of the ulnar nerve.

Evaluation of Rehabilitation Techniques for Traumatic Ulnar Nerve Injuries After Surgical Repair: A Systematic Review.

BACKGROUND: Traumatic ulnar nerve injuries often result in significant loss of motor and sensory function, negatively impacting patients' quality of life. Physical rehabilitation is crucial for recovery, but standardized treatment protocols are lacking. This study aims to systematically review rehabilitation techniques to identify future research direction and improve existing protocols for ulnar nerve injury patients. METHODS: PubMed, Embase, CINAHL, Cochrane CENTRAL, Web of Science, and Scopus were queried from inception until July 31, 2023. Articles containing axonotmesis or neurotmesis injuries of the ulnar nerve were included. Reviews, opinions, editorials, technical reports without clinical outcomes, conference abstracts, non-English text, nonhuman studies, and studies without adult patients were excluded. Three independent reviewers performed screening and data extraction using Covidence, and risk of bias assessments utilizing Cochrane and JBI tools. Because of article heterogeneity, a narrative review was conducted. The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database, registration number CRD42023442016. RESULTS: This systematic review included one randomized controlled trial and four observational studies (103 patients), which exhibited differences in study quality. Overall, motor and sensory outcomes improved after rehabilitation. Rehabilitation techniques varied widely, and early sensory reeducation appeared to improve sensory function. Only two studies included patient-reported outcomes. CONCLUSIONS: Diverse rehabilitation techniques are used to address ulnar nerve injuries. The low number of included studies, differences in study quality, and small sample size underscore the need for larger and more inclusive studies to improve functional recovery after ulnar nerve injuries. Future research should consider the impact of patient and injury characteristics to develop comprehensive treatment guidelines for these patients.

Nerve conduction, latency, and its association with hand function in young men.

INTRODUCTION: The median and ulnar nerves have been suggested to play a significant role in hand function; however, there are insufficient data to determine the strength of this association. This study aimed to investigate the correlation between hand function as measured with the Grooved pegboard test (GPT) and conduction velocity and latency of the median and ulnar nerves. METHODS: We collected convenience samples in the College of Medicine, KSAU-HS. We used GPT to characterize hand function and performed measured nerve conduction velocity (NCV) and latency of the ulnar and median nerves of both hands. We used the Edinburgh handedness inventory (EHI) to determine hand dominance. RESULTS: We recruited 28 healthy medical students aged 20-29 years (mean: 21.46 ± 1.62 years). Most were right-handed (n = 25, 89.3%), with a mean EHI score of 302 ± 210. The mean GPT time was significantly faster in the dominant (65.5 ± 6.4 s) than in the non-dominant (75.0 ± 9.6 s) hand. The NCV for the ulnar nerve of the dominant hand was significantly correlated with GPT (r = -0.52, p = 0.005) while median nerve was not correlated (0.24, p = 0.21). Regression analysis and collinearity test showed that the ulnar NCV explained 20% of the variance in GPT of the dominant hand (R2 = 0.203, p = 0.016). CONCLUSION: The ulnar nerve conduction velocity, explained 20% of the variance in GPT times of the young men. Performance on this biomarker of neurological health seems to be more influenced by other factors in healthy young individuals.

Spared ulnar nerve injury results in increased layer III-VI excitability in the pig somatosensory cortex.

This study describes cortical recordings in a large animal nerve injury model. We investigated differences in primary somatosensory cortex (S1) hyperexcitability when stimulating injured and uninjured nerves and how different cortical layers contribute to S1 hyperexcitability after spared ulnar nerve injury. We used a multielectrode array to record single-neuron activity in the S1 of ten female Danish landrace pigs. Electrical stimulation of the injured and uninjured nerve evoked brain activity up to 3 h after injury. The peak amplitude and latency of early and late peristimulus time histogram responses were extracted for statistical analysis. Histological investigations determined the layer of the cortex in which each electrode contact was placed. Nerve injury increased the early peak amplitude compared with that of the control group. This difference was significant immediately after nerve injury when the uninjured nerve was stimulated, while it was delayed for the injured nerve. The amplitude of the early peak was increased in layers III-VI after nerve injury compared with the control. In layer III, S1 excitability was also increased compared with preinjury for the early peak. Furthermore, the late peak was significantly larger in layer III than in the other layers in the intervention and control group before and after injury. Thus, the most prominent increase in excitability occurred in layer III, which is responsible for the gain modulation of cortical output through layer V. Therefore, layer III neurons seem to have an important role in altered brain excitability after nerve injury.

Nerve sonography to detect intraneural microvascularity in patients with peripheral neuropathy.

OBJECTIVE: We assessed microvessel flow within peripheral nerves using nerve sonography in patients with peripheral neuropathy. METHODS: This study included consecutive patients with peripheral neuropathy who were admitted to our hospital. The patients were divided into two groups: inflammatory neuropathies for immune-mediated neuropathies, such as Guillain - Barré syndrome and chronic inflammatory demyelinating polyneuropathy, and the rest were defined as non-inflammatory neuropathies. We assessed nerve size and intraneural blood flow at four sites on each median and ulnar nerve. Blood flow was evaluated using color Doppler imaging, advanced dynamic flow (ADF), and superb microvascular imaging (SMI) techniques. RESULTS: Thirty-nine patients (median age, 60.0 years; 20 male) were enrolled in this study. An increase in intraneural blood flow was observed in five patients when evaluated by color Doppler, five patients by ADF, and 13 patients by SMI. An overall analysis of the three methods showed that intraneural blood flow was significantly higher in patients with inflammatory neuropathy than in those with non-inflammatory neuropathy (54.2% vs. 0%, p = 0.0005). CONCLUSIONS: Intraneural hypervascularization is more frequent in patients with inflammatory neuropathy than in those with non-inflammatory neuropathy. SIGNIFICANCE: Evaluation of microvessel flow within peripheral nerves may contribute to the diagnosis of peripheral neuropathy.

The Crossing Motor Ulnar Nerve Branch at Elbow.

BACKGROUND AND OBJECTIVES: Cubital tunnel syndrome is the second most common nerve entrapment, and understanding the anatomy is crucial for the success of the nerve release. During ulnar nerve release for cubital tunnel syndrome, a motor branch is frequently encountered crossing anteriorly over the ulnar nerve from its medial/ulnar side proximally to the lateral/radial side distally. Little has been noted about this crossing branch in the literature. In this anatomic study, we sought to characterize this branch further and discuss its potential significance in cubital tunnel release. METHODS: We performed a cadaveric dissection of 48 elbow specimens as if performing a cubital tunnel release. We assessed for the presence of the crossing motor branch of the ulnar nerve and measured the distance from the medial epicondyle to the branch takeoff and to its target of innervation. RESULTS: Of our 48 specimens, 34 (71%) were noted to have a crossing motor branch at the area of compression by the deep flexor carpi ulnaris muscle fascia (common aponeurosis). On average, the distance from the medial epicondyle to the branch origin from the ulnar nerve was 18.2 mm and to the target muscle innervation was 28.4 mm. CONCLUSION: Identifying this branch is important for performing a cubital tunnel release, and awareness of this anatomy during ulnar nerve decompression procedures may help avoid injury to this motor branch.

Dorsal ulnar cutaneous nerve conduction study based on nerve ultrasound.

This study investigates the impact of the anatomical separation point of the dorsal ulnar cutaneous nerve (DUCN) on nerve conduction studies (NCS). Involving 25 subjects with DUCN NCS findings, it utilizes ultrasound to mark the DUCN's divergence from the ulnar nerve. NCS was performed at four points relative to the separation point. The findings indicate the maximal amplitudes occurred 2 cm distal to the separation point. The study suggests it is ideal when the stimulation is performed between the seperation point and 2 cm distal to it.

Revision surgery for recurrent ulnar nerve compression following failed subcutaneous transposition.

BACKGROUND: Recurrent ulnar nerve compression after primary anterior subcutaneous transposition is relatively rare, and revision surgery is challenging. This study retrospectively evaluated the clinical outcomes of revision anterior subcutaneous transposition for recurrent ulnar nerve compression. METHODS: Eight patients who underwent revision anterior subcutaneous transposition for recurrent ulnar nerve compression were enrolled in this study. The outcomes were based on preoperative and postoperative symptoms, physical examination findings, and electromyographic evaluation. RESULTS: Ulnar nerve enlargement was preoperatively found in all patients with a mean cross sectional area of 0.15 cm2 (range, 0.14-0.18 cm2). Intraoperative findings showed that recurrent compression occurred in three areas, including the medial intermuscular septum (n = 5), the medial epicondyle (n = 6) and nerve entrance to forearm fascia (n = 1). Post-operation, significant improvements were observed in ring/little finger numbness (from severe to mild, p = 0.031), grip strength (from 48.00% to 80.38% of the intact side, p < 0.001) and McGowan grade (from Grade III to Grade I, p = 0.049). Postoperative electromyography test also showed significant improvement in motor nerve conduction at elbow (velocity, 23.30 ± 9.598 vs. 35.30 ± 9.367, p = 0.012; amplitude, 3.40 ± 3.703 vs. 5.65 ± 2.056, p = 0.007) and sensory nerve conduction at wrist (velocity, 27.04 ± 22.450 vs. 36.45 ± 18.099, p = 0.139; amplitude, 1.44 ± 1.600 vs. 4.00 ± 2.642, p = 0.011). Seven of the eight patients reported satisfaction with the postoperative results. CONCLUSIONS: Revision anterior subcutaneous transposition was an effective treatment for recurrent ulnar nerve compression from prior failed procedures.

Comparative risk of ulnar nerve injury in pediatric supracondylar humeral fractures: a multicenter evaluation of Kirschner wire fixation techniques.

PURPOSE: This multicenter, retrospective cohort study aimed to compare the risk of ulnar nerve injury in pediatric supracondylar humeral fractures treated with percutaneous lateral-pins, blinded-crossed-pins, and crossed-pins with a mini-incision. METHODS: Data were collected from 1705 children treated between January 2010 and December 2023 at four orthopedic centers in Colombia. The incidence of postoperative ulnar nerve injury was compared among three fixation techniques: lateral-pin, blinded-crossed-pin, and crossed-pin with a mini-incision. RESULTS: A statistically significant difference in nerve injury rates was observed between the lateral-pin and both blinded-crossed-pin and mini-incision crossed-pin techniques (p < 0.001), with the lateral-pin technique demonstrating a significantly lower risk of injury. No significant difference was found between the blinded-crossed-pin and mini-incision crossed-pin techniques (p = 0.67). CONCLUSION: Crossed-pin fixation was associated with a higher incidence of ulnar nerve injury, regardless of the use of a mini-incision. The lateral-pin technique remains the safest option for minimizing iatrogenic nerve injury. There is insufficient evidence to support the mini-incision as a safer alternative to traditional crossed-pin fixation.

Clinico-anatomical insight into the unusual course, branching pattern and connections of ulnar nerve: A narrative review.

Ulnar nerve originates from the lower trunk as a branch from anterior division, continuing as a branch from medial cord of the brachial plexus. It receives fibres from anterior rami of cervical nerve root 8 and the first thoracic nerve root. Ulnar nerve injury accounts for being the most common vessel of upper limb that results in hospitalisation. Knowing the variability in the anatomical pattern of ulnar nerve and its communication with various branches of nerves in the vicinity can have implications. The current narrative review comprised literature search on Google, Google Scholar and PubMed databases for articles published between 2015 and 2023 on the subject. The insight and understanding of the related ulnar nerve anatomy is likely to be of prodigious help to anatomists, surgeons, physicians and radiologists in preventing unexpected outcomes in the future.

Elbow Arthroscopy: Pearls to Avoid Nerve Injuries.

Elbow arthroscopy is a useful tool that can be applied in a variety of surgical indications. However, performing the procedure safely demands a thorough understanding of the proximity of neurovascular structures around the elbow. Although nerve injuries in elbow arthroscopy are rare, complications can further be avoided by adhering to a set of principles designed to protect the surrounding neurovascular structures. Before making portals, the surgeon should palpate and mark the ulnar nerve to confirm its location in the groove. Next, the joint should be insufflated with fluid to distend the joint capsule and increase the distance between instruments and the anterior neurovascular structures. Anterior portals ideally should be made proximal to the medial and lateral epicondyles, thereby increasing distance from the median and radial nerve, respectively. Once in the joint, it is critical to stay oriented by maintaining instruments and the articular surfaces in the same view. Special caution should be exercised when in proximity to the capsule in the posteromedial gutter to protect the ulnar nerve. Similarly, the anterior inferior capsule should be approached with caution, as its violation puts branches of the radial nerve, specifically the posterior interosseous nerve, at risk. Elbow arthroscopy can be safely performed with proper knowledge and application of anatomy around the elbow when making portals and understanding at-risk areas beyond the capsule when working within the joint.

Nerve Versus Tendon Transfers in the Management of Isolated Upper Extremity Peripheral Nerve Injuries.

Upper extremity peripheral nerve injuries present functional deficits that are amenable to management by tendon or nerve transfers. The principles of tendon and nerve transfers are discussed, with technical descriptions of preferred tendon and nerve transfers for radial, median, and ulnar nerve injuries.

3D fascicular reconstruction of median and ulnar nerve: initial experience and comparison between high-resolution ultrasound and MR microscopy.

BACKGROUND: The complex anatomy of peripheral nerves has been traditionally investigated through histological microsections, with inherent limitations. We aimed to compare three-dimensional (3D) reconstructions of median and ulnar nerves acquired with tomographic high-resolution ultrasound (HRUS) and magnetic resonance microscopy (MRM) and assess their capacity to depict intraneural anatomy. METHODS: Three fresh-frozen human upper extremity specimens were prepared for HRUS imaging by submersion in a water medium. The median and ulnar nerves were pierced with sutures to improve orientation during imaging. Peripheral nerve 3D HRUS scanning was performed on the mid-upper arm using a broadband linear probe (10-22 MHz) equipped with a tomographic 3D HRUS system. Following excision, nerves were cut into 16-mm segments and loaded into the MRM probe of a 9.4-T system (scanning time 27 h). Fascicle and nerve counting was performed to estimate the nerve volume, fascicle volume, fascicle count, and number of interfascicular connections. HRUS reconstructions employed artificial intelligence-based algorithms, while MRM reconstructions were generated using an open-source imaging software 3D slicer. RESULTS: Compared to MRM, 3D HRUS underestimated nerve volume by up to 22% and volume of all fascicles by up to 11%. Additionally, 3D HRUS depicted 6-60% fewer fascicles compared to MRM and visualized approximately half as many interfascicular connections. CONCLUSION: MRM demonstrated a more detailed fascicular depiction compared to 3D HRUS, with a greater capacity for visualizing smaller fascicles. While 3D HRUS reconstructions can offer supplementary data in peripheral nerve assessment, their limitations in depicting interfascicular connections and small fascicles within clusters necessitate cautious interpretation. CLINICAL RELEVANCE STATEMENT: Although 3D HRUS reconstructions can offer supplementary data in peripheral nerve assessment, even in intraoperative settings, their limitations in depicting interfascicular branches and small fascicles within clusters require cautious interpretation. KEY POINTS: 3D HRUS was limited in visualizing nerve interfascicular connections. MRM demonstrated better nerve fascicle depiction than 3D HRUS. MRM depicted more nerve interfascicular connections than 3D HRUS.

Intraoperative Subperiosteal Elevation of the Ulnar Nerve Is a Safe and Effective Way to Minimize Postoperative Ulnar Neuritis in Distal Humerus Fractures.

OBJECTIVES: To describe subperiosteal elevation of the ulnar nerve and compare to anterior transposition and in situ decompression techniques. DESIGN: Retrospective comparative study. SETTING: Urban Level 1 trauma center. PATIENT SELECTION CRITERIA: Distal humerus fractures (Orthopaedic Trauma Association/AO 13) treated with open reduction internal fixation between 2014 and 2022. OUTCOME MEASURES AND COMPARISONS: Rate of preoperative and postoperative neuritis grouped by the management of the ulnar nerve. During subperiosteal elevation, the ulnar nerve was identified and raised off the ulna subperiosteally and mobilized submuscularly anterior to the medial epicondyle to protect the nerve. The nerve was released only laterally off the triceps, and the medial soft tissue attachment is maintained. The main outcome measurements was rate of neuritis documented within physical examination. RESULTS: Within the 125 patients, 35 underwent subperiosteal elevation (mean age of 56 ± 21 years, 57% female), 63 in situ decompression (mean age of 60 ± 18 years, 46% female), and 27 anterior transposition (mean age of 55 ± 20 years, 59% female). Preoperative ulnar neuritis was present in 34%, 21%, and 33% of patients treated with subperiosteal elevation, in situ decompression, and anterior transposition, respectively ( P = 0.26). At postoperative evaluation, symptom resolution occurred in 100%, 69%, and 33% of patients treated with subperiosteal elevation, in situ decompression, and anterior transposition, respectively ( P = 0.003). New cases of postoperative ulnar neuritis occurred in 6%, 8%, and 26% of patients treated with subperiosteal elevation, in situ decompression, and anterior transposition, respectively ( P = 0.054). Subperiosteal elevation outperformed anterior transposition regarding postoperative ulnar neuritis ( P = 0.019) and symptom resolution ( P = 0.002) and performed similarly to in situ decompression ( P > 0.05). On multiple regression analysis, anterior transposition was an independent risk factor for postoperative neuritis (OR = 5.2, P = 0.023). CONCLUSIONS: Subperiosteal elevation is an effective way to minimize postoperative neuritis and similar to an in situ decompression during distal humerus fracture fixation. Based on the results of this cohort, authors recommended that anterior transposition of the ulnar nerve be used with caution due to its association with postoperative ulnar neuritis. LEVEL OF EVIDENCE: Therapeutic, Level III. See Instructions for Authors for a complete description of levels of evidence.

Direct Suturing of Ulnar or Median Nerve Defects in High-Degree Elbow Flexion: An Experimental Cadaver Study.

OBJECTIVE: The aim of this study is to determine the maximum loss of median and ulnar nerve substances that can be treated by direct suture in elbow flexion and to quantify this elbow flexion. The other objective is to determine the participation of the wrist position in this direct suture in elbow flexion. METHODS: We performed an experimental study on 6 ulnar nerve lesions and 6 median nerve lesions. For each defect, a direct tensionless suture was performed with elbow flexion and in three different positions of the wrist (wrist extension, neutral position, and wrist flexion). RESULTS: A 90° elbow flexion allowed direct suturing of defects up to 40 mm in the 3 positions of the wrist. A bowstringing effect (i.e., increase of the perpendicular distance of the nerve from the axis of rotation of the elbow) was noted starting from 25 mm of nerve defect. Wrist extension placed tension on the nerve suture for both nerves. CONCLUSIONS: The results of this first anatomical study clarified the conditions for direct suturing of ulnar and median nerve defects in the flexed elbow position and flexed wrist position. This is an approach to consider for limited nerve defects to the elbow or when allograft harvesting is to be avoided.