Role of Preoperative Nerve Conduction Studies for Penetrating Hand Injuries Involving the Median Palmar Cutaneous Nerve.

Penetrating lacerations to the hand are a common cause of nerve injury and can lead to debilitating pain and numbness in the distribution of the nerve affected. Owing to an overlap in the cutaneous innervation from different sensory nerves, clinically identifying the injured nerve can be difficult. We present a novel case of isolated injury to the palmar cutaneous nerve from a penetrating knife injury which was detected using 'comparison waveform' nerve conduction studies. Using this technique, we can isolate injuries to the palmar cutaneous branch of the median nerve (PCBmdn) from the median nerve, dorsal radial sensory nerve, and lateral antebrachial cutaneous nerve. In addition, sensory nerve testing identified conduction block as the mechanism of injury, which resolved after surgery at 8 weeks postoperatively. Preoperative nerve conduction study can discern the level of nerve injury to PCBmdn only, thus eliminating the need for median and radial nerve exploration at the forearm, unnecessary incisions, pain, and scarring. The objective of this case report is to illustrate the value of preoperative comparison waveform nerve conduction study, particularly the PCBmdn, in patients presenting with neurologic deficits who have sustained penetrating lacerations to the hand.

Median Nerve Palsy in Pediatric Supracondylar Humerus Fractures Recovers Faster With Open Than Closed Reduction.

BACKGROUND: Management of supracondylar humerus fractures (SCHF) with coexisting median nerve injury is controversial. Although many nerve injuries improve with the reduction and stabilization of the fracture, the speed and completeness of recovery are unclear. This study investigates median nerve recovery time using the serial examination. METHODS: A prospectively maintained database of SCHF-related nerve injuries referred to a tertiary hand therapy unit between 2017 and 2021 was interrogated. Factors related to the injury (vascularity, Gartland grade, open vs. closed fracture) and treatment (fixation modality, adequacy, timing of reduction, vascular and nerve intervention, and secondary procedures) were assessed.Primary outcomes were the motor recovery of Medical Research Council (MRC) grade 4 or 5 in flexor pollicis longus or flexor digitorum profundus (index) and detection of the 2.83 Semmes Weinstein monofilament.A retrospective clinical note review of all SCHF presenting during the same period was also conducted. RESULTS: Of 1096 SCHF, 74 (7%) had an associated median nerve palsy. Twenty-one patients [mean age 7 years (SD 1.6)] with SCHF-related median nerve injuries underwent serial examination. Nineteen (90%) were modified Gartland III or IV, and 10 (48%) were pulseless on presentation. The mean follow-up was 324 days.The mean motor recovery time was 120 days (SD 71). Four (27%) and 2 (13%) patients had not achieved MRC grade 4 by 6 months and 2 years, respectively. Only 50% attained MRC grade 5 at 2 years.When compared with closed reduction, those who underwent open reduction recovered motor function 80 days faster (mean 71 vs. 151 d, P =0.03) and sensory function 110 days faster (52 vs. 162, P =0.02). Fewer patients recovered after closed reduction (8 of 10) than open (5 of 5).Modified Gartland grade, vascular status, adequacy of reduction, and secondary surgery were not associated with recovery time. CONCLUSIONS: Median nerve recovery seems to occur slower than previously thought, is often incomplete, and is affected by treatment decisions (open vs. closed reduction). Retrospective reporting methods may overestimate median nerve recovery. LEVEL OF EVIDENCE: Level III-therapeutic.

Role of ultrasonography for evaluation of nerve recovery in repaired median nerve lacerations.

This study aimed to investigate whether ultrasonographic inspection of the repair site of median nerve lacerations may provide useful evidence about the functional outcome in the affected hand. Forty-three patients with complete transection of the median nerve at the distal forearm were examined at a median of 40.9 months after operation by detailed ultrasonographic imaging and clinical assessment of the affected hand by the Michigan Hand Questionnaire and Rosén-Lundborg Protocol to investigate the quality of nerve healing. The continuity of individual nerve fascicles was assessed and the cross-sectional area of the enlarged nerve at the repair site was measured and compared with the contralateral median nerve at the same level. An enlargement ratio for the repair site of each nerve was calculated and compared with the numeric results obtained from the two clinical tests. A statistically significant reverse correlation was observed between nerve enlargement and the functional results of the repaired nerve.Level of evidence: IV.

Anatomic Study of the Motor Branch of the Ulnar Nerve Regarding Carpal Tunnel Surgery: A Cadaveric Study.

Background: Motor branch of the ulnar nerve (MUN) injury during carpal tunnel surgery is rare and it should never be injured during carpal tunnel release (CTR). However, an iatrogenic injury of the MUN can cause catastrophic physical and mental suffering. The aim of our study is to understand the anatomy of the MUN in relation to carpal tunnel in order to prevent iatrogenic injury during CTR. Methods: We dissected 34 fresh cadaver hands and located the MUN in relation to the anatomical axis used for carpal tunnel surgery. Possible mechanisms of injury and the vulnerable area of the MUN were determined along the dissection. Results: The MUN turned towards the thumb distal to hook of hamate. It then travelled on the floor of the carpal tunnel which was formed by intrinsic hand muscles under flexor tendons. The nerve located at 29.39 ± 7.41, 35.01 ± 3.14 and 38.79 ± 4.03 mm (Mean ± SD) in the central axis of ring finger, the vertical axis of the third web-space and the central axis of middle finger respectively. The nerve's turning point, 10.9 ± 2.63 mm distal to the centre of hook of hamate where it lies just below the level of the transverse carpal ligament. Conclusions: Surgeons should be aware of the nerve's location. Surgical dissection or passing of any surgical instruments around the hook of hamate should be done with care. Level of Evidence: Level IV (Therapeutic).

Radius palmar plate removal without carpal tunnel release: Correlation between plate position and median nerve symptoms.

We aimed to report the clinical results of volar plate removal without carpal tunnel release in patients with late-onset median neuropathy and to evaluate the relationship between plate position and median nerve symptoms. Part I. Twelve consecutive patients with late-onset median neuropathy treated with volar plate removal without carpal tunnel release were enrolled for analysis. Pre- and post-operative Tinel sign, Phalen and Ten test, subjective rating of tingling sensation, Mayo wrist score and Disabilities of the Arm, Shoulder and Hand (DASH) score were collected. Part II. 232 consecutive patients underwent volar plating for distal radius fracture. The relationships between median nerve symptoms and volar plate prominence on the Soong classification, fracture classification, gender and age were investigated. All cases except one showed complete symptom resolution at final follow-up, with negative Tinel sign and Ten test score of 10/10. Tingling was rated 0 at final follow-up. Mean Mayo wrist and DASH scores improved to 86.7 and 23.1, respectively. The incidence of the median nerve symptoms in our cohort was 5.6%. Even though the odds ratio in Soong grade 2 was 4.0957 (95% CI, 0.93-16.9) compared to the combination of grades 0 and 1, no statistically significant relationship was found between the median nerve symptoms and volar plate prominence (p > 0.05). Plate removal without carpal tunnel release adequately relieved symptoms of late-onset median neuropathy after volar plating in patients with distal radius fracture. LEVEL OF EVIDENCE: IV; Therapeutic.

The safety and accuracy of various carpal tunnel injection techniques.

PURPOSE: Carpal tunnel (CT) syndrome continues to be a commonly treated hand pathology. We aimed to evaluate several CT injection techniques for (1) spatial accuracy within the CT and (2) risk of median nerve (MN) injury. Our purpose was to evaluate for any significant differences in accuracy of needle placement within the carpal tunnel and final distance between the needle tip and the MN with each technique. METHODS: Fifteen fresh frozen cadaveric arms were used for this study. Six different injection techniques for CT injection were performed on each specimen, including palmaris longus, ulnar to flexor carpi radialis, trans-flexor carpi radialis, volar radial, volar ulnar, and direct through the palm techniques. After needle placement, a standard open CT release was performed to assess for accuracy of placement within the CT and measure needle position in relation to the MN and other anatomic structures. RESULTS: Accurate intra-CT needle placement was seen in 91% of injections. While there was no significant difference between injection techniques for distance to nearest tendon (p = 0.1531), the trans-flexor carpi radialis (tFCR), volar radial (VR), and volar ulnar (VU) techniques consistently provided the greatest intra-CT distance from needle tip to median nerve (p = 0.0019). The least incidence of intraneural needle placement was found with the tFCR and VR approaches. CONCLUSION: All six injection techniques reliably enter the CT space. The lowest risk to the MN was found with tFCR and VR techniques, and we recommend these techniques for safe and effective needle placement to avoid iatrogenic intraneural injection. LEVEL OF EVIDENCE: Level V: Cadaveric Study.

The position of the median nerve in relation to the palmaris longus tendon at the wrist: a study of 784 MR images.

Iatrogenic injury of the median nerve has been reported after endoscopic carpal tunnel release and corticoid injection. In 784 MR images of the wrist, the position of the median nerve in relation to the palmaris longus tendon was analysed. The ulnar edge of the median nerve was found medial to the palmaris longus tendon in 14% and 36% of patients at the proximal wrist crease and entrance of the carpal tunnel, respectively, compared with 23% and 40% of patients with carpal tunnel syndrome (88 patients). The position of the median nerve in relation to the palmaris longus tendon varies widely. It is suggested that the palmaris longus tendon may not be considered a safe landmark to locate the position of the median nerve and care should be taken when introducing an endoscopic instrument or during steroid injection for carpal tunnel syndrome.Level of evidence: IV.

Transient Proximal Median Nerve Entrapment in a Tetraplegic Hand Cyclist Following a 24-Hour Endurance Race.

Median nerve entrapment is a frequent disorder encountered by all clinicians at some point of their career. Affecting the distal median nerve, entrapment occurs most frequently at the level of the wrist resulting in a carpal tunnel syndrome. Median nerve entrapment may also occur proximally giving rise to the much less frequent pronator teres syndrome and even less frequent anterior interosseous nerve syndrome, which owing to the paucity of cases may prove challenging to diagnose. An unusual case of anterior interosseous syndrome precipitated by extraordinary exertion in a tetraplegic endurance athlete is presented with ancillary dynamometric, electrodiagnostic, ultrasonographic, and biochemical findings.

Risk of nerve injury during elbow arthroscopy: ultrasonographic evaluation of preoperative patients.

BACKGROUND: To clarify the real risk of nerve injury during elbow arthroscopy, the distances of the radial and median nerves to the elbow joint were investigated using ultrasonography in patients who underwent surgery. METHODS: A total of 35 patients who underwent arthroscopic surgery of the elbow were investigated. The distances of the nerves to the capsule and bony landmarks were measured using ultrasonography. The radial nerve distances were measured at the capitellum, joint space, radial head, and radial neck levels. The median nerve distances were measured at the trochlear, joint space, and coronoid process levels. The patients were divided into 2 groups: nine patients in the hydrarthrosis (HA) group and 26 patients in the non-hydrarthrosis (non-HA) group. HA was defined as the intra-articular effusion on magnetic resonance imaging scans. RESULTS: The radial nerve ran closer to the capsule at the radial neck level in the HA group than in the non-HA group (2.0 mm vs. 5.9 mm, P < .01). In the non-HA group, the radial nerve ran closer to the radial head than in the HA group (6.3 mm vs. 8.5 mm, P = .01). The median nerve ran closer to the capsule at the trochlear level in the HA group than in the non-HA group (5.2 mm vs. 8.8 mm, P < .01). Nerves at a distance of ≤2 mm from the capsule were found in 7 patients at the radial neck of the radial nerve and in 2 patients at the trochlear region of the median nerve in the HA group. In the non-HA group, they were found in 3 patients at the radial head and in 1 patient at the joint space of the radial nerve. CONCLUSIONS: The dangerous locations for nerve injury during elbow arthroscopy vary according to hydrarthrosis, and this risk should be recognized during arthroscopic surgery.

Imaging of Nerve Disorders in the Elbow.

Neuropathies of the elbow represent a spectrum of disorders that involve more frequently the ulnar, radial, and median nerves. Reported multiple pathogenic factors include mechanical compression, trauma, inflammatory conditions, infections, as well as tumor-like and neoplastic processes. A thorough understanding of the anatomy of these peripheral nerves is crucial because clinical symptoms and imaging findings depend on which components of the affected nerve are involved. Correlating clinical history with the imaging manifestations of these disorders requires familiarity across all diagnostic modalities. This understanding allows for a targeted imaging work-up that can lead to a prompt and accurate diagnosis.

Combined Use of Chitosan-PGLA Nerve Grafts and Bone Marrow Mononuclear Cells to Repair a 50-mm-long Median Nerve Defect Combined with an 80-mm-long Ulnar Nerve Defect in the Human Upper Arm.

BACKGROUND: Severe peripheral nerve injury, especially the long-distance peripheral nerve defect, causes severe functional disability in patients. There is always a lack of effective repair methods for clinic, and those in practice are associated with side effects. A case study was performed to observe the regenerative outcomes of the surgical repair of long-distance peripheral nerve defects in the upper arm with chitosan-poly(glycolide-co-lactide) (PGLA) nerve grafts combined with bone marrow mononuclear cells (BMMCs). METHODS: The right upper arm of a 29-year-old woman was injured, leaving a 50-mm-long median nerve defect, an 80-mm-long ulnar nerve defect, and muscle and blood vessel disruptions. The nerve defects were repaired by implanting BMMC-containing chitosan-PGLA nerve grafts on the 40th day after injury. A series of functional assessments were carried out from 2 weeks to 66 months after surgical repair. Sensory function was assessed by the pinprick test, two-point discrimination test and Semmes-Weinstein monofilament test. Motor function was evaluated by the range of motion of the wrist joint and muscle power. Autonomic function was monitored by laser-Doppler perfusion imaging (LDPI). Tissue morphology was observed through ultrasonic investigations. RESULTS: No adverse events, such as infection, allergy, or rejection, caused by the treatment were detected during the follow-up period. Sensory and pinprick nociception in the affected thumb, index, and middle fingers gradually restored at 6th month after surgery. The monofilament tactile sensation was 0.4 g in the terminal finger pulp of the thumb and index finger, 2.0 g in the middle finger, and greater than 300 g in the ring finger and little finger at the 66th month. Motor function recovery was detected at the 5th month after surgery, when the muscle strength of the affected forearm flexors began to recover. At the 66th month after surgery, the patient's forearm flexor strength was grade 4, with 80° of palmar flexion, 85° of dorsal extension, 8° of radial deviation, 40° of ulnar deviation, 40° of anterior rotation, and 85° of posterior rotation of the affected wrist. The patient could perform holding, picking up, and some other daily activities with the affected hand. The patient's sweating function of the affected hand was close to the level of the healthy hand. LDPI showed that the skin blood flow perfusion was significantly increased, with perfusion similar to on the normal side in some areas. Neuromusculoskeletal ultrasonography showed the presence of nerve structures. CONCLUSION: These results suggest that chitosan-PGLA nerve grafts combined with BMMCs could effectively repair long-distance nerve defects and achieve good clinical results.

Asymptomatic Penetration of the Median Nerve by a Peripherally Inserted Central Catheter: A Case Report.

We report a rare case in which a peripherally inserted central catheter (PICC) asymptomatically penetrated the median nerve. The patient was a 71-year-old man who displayed no neurological symptoms until 4 days after PICC placement. An ultrasound scan revealed that the PICC had penetrated the median nerve. He underwent surgery to remove the catheter and had no sequelae. When placing a PICC, selecting the brachial vein as a puncture site is associated with a high risk of nerve injury. Furthermore, circumspect observation is needed until withdrawal as neurological symptoms may be absent even when the catheter has punctured a nerve.

An Anatomical Variant of the Palmar Cutaneous Branch of the Median Nerve: A Case Report.

There is a risk of injury to the palmar cutaneous branch of the median nerve (PCBMN) during a volar approach to the carpus or the distal radius. Anatomic variations of the PCBMN increase this risk. We report an anatomic variant of the PCBMN that coursed superficial and radial to the flexor carpi radialis (FCR), reinforcing the need for meticulous subcutaneous dissection to protect the nerve during a volar approach to the distal radius. In this case, identification of the PCBMN variant warranted a modified surgical approach, ulnar to the FCR instead of radial in order to avoid iatrogenic injury. Level of Evidence: Level V (Therapeutic).

Does hyperbaric oxygen therapy facilitate peripheral nerve recovery in upper extremity injuries? A prospective study of 74 patients.

PURPOSE: Several experimental studies have investigated the effects of hyperbaric oxygen therapy (HBOT) on peripheral nerve regeneration. However, to the best of our knowledge, clinical studies to evaluate the effects of HBOT on peripheral nerve recovery are seldom performed. The aim of our study was to investigate the efficacy of HBOT following primary nerve repair in patients with upper extremity nerve injuries. METHODS: Patients admitted to our hospital between 2015 and 2019 with ulnar and median nerve injuries were included in the study. Patients were randomized based on their application dates and divided into two different groups. Patients who received HBOT following standard epineural nerve repair were included in group 1, while patients who only underwent epineural nerve repair were included in group 2. All patients were followed up at 3, 6, and 12 months post-treatment and evaluated through electroneuromyography analysis of the traumatized nerve, injured nerve-related muscle strength, and two-point discrimination test. RESULTS: Impulse transmission of injured nerves to the end organ was faster in group 1. Further, ENMG parameters demonstrated that injured nerves of patients in group 1 recovered faster. Patients in group 1 also reached higher power score and had significantly more rapid motor recovery than patients in group 2. CONCLUSION: This prospective study of upper extremity injuries demonstrated the favorable effects of HBOT on nerve recovery both clinically and electrophysiologically following nerve repair. One HBOT session each day for 5 days after surgical treatment can decrease morbidity and facilitate recovery.

Surgical Innovations to Restore Function in Pediatric Peripheral Nerve Conditions.

Peripheral nerve injuries in children can result in devastating lifelong deficits. Because of the time-sensitive nature of muscle viability and the limited speed of nerve regeneration, early recognition and treatment of nerve injuries are essential to restore function. Innovative surgical techniques have been developed to combat the regenerative length and speed; these include nerve transfers. Nerve transfers involve transferring a healthy, expendable donor nerve to an injured nerve to restore movement and sensation. Nerve transfers are frequently used to treat children affected by conditions, including UE trauma, brachial plexus birth injury, and acute flaccid myelitis. Pediatricians play an important role in the outcomes of children with these conditions through early diagnosis and timely referrals. With this review, we aim to provide awareness of state-of-the-art surgical treatment options that significantly improve the function of children with traumatic nerve injuries, brachial plexus birth injury, and acute flaccid myelitis.

Effect of unacylated ghrelin on peripheral nerve regeneration.

Ghrelin is a circulating peptide hormone released by enteroendocrine cells of the gastrointestinal tract as two forms, acylated and unacylated. Acylated ghrelin (AG) binds to the growth hormone secretagogue receptor 1a (GHSR1a), thus stimulating food intake, growth hormone release, and gastrointestinal motility. Conversely, unacylated GHR (UnAG), through binding to a yet unidentified receptor, protects the skeletal muscle from atrophy, stimulates muscle regeneration, and protects cardiomyocytes from ischemic damage. Recently, interest about ghrelin has raised also among neuroscientists because of its effect on the nervous system, especially the stimulation of neurogenesis in spinal cord, brain stem, and hippocampus. However, few information is still available about its effectiveness on peripheral nerve regeneration. To partially fill this gap, the aim of this study was to assess the effect of UnAG on peripheral nerve regeneration after median nerve crush injury and after nerve transection immediately repaired by means of an end-to-end suture. To this end, we exploited FVB1 Myh6/Ghrl transgenic mice in which overexpression of the ghrelin gene (Ghrl) results in selective up-regulation of circulating UnAG levels, but not of AG. Regeneration was assessed by both functional evaluation (grasping test) and morphometrical analysis of regenerated myelinated axons. Results obtained lead to conclude that UnAG could have a role in development of peripheral nerves and during more severe lesions.

The Efficacy of Schwann-Like Differentiated Muscle-Derived Stem Cells in Treating Rodent Upper Extremity Peripheral Nerve Injury.

BACKGROUND: There is a pressing need to identify alternative mesenchymal stem cell sources for Schwann cell cellular replacement therapy, to improve peripheral nerve regeneration. This study assessed the efficacy of Schwann cell-like cells (induced muscle-derived stem cells) differentiated from muscle-derived stem cells (MDSCs) in augmenting nerve regeneration and improving muscle function after nerve trauma. METHODS: The Schwann cell-like nature of induced MDSCs was characterized in vitro using immunofluorescence, flow cytometry, microarray, and reverse-transcription polymerase chain reaction. In vivo, four groups (n = 5 per group) of rats with median nerve injuries were examined: group 1 animals were treated with intraneural phosphate-buffered saline after cold and crush axonotmesis (negative control); group 2 animals were no-injury controls; group 3 animals were treated with intraneural green fluorescent protein-positive MDSCs; and group 4 animals were treated with green fluorescent protein-positive induced MDSCs. All animals underwent weekly upper extremity functional testing. Rats were euthanized 5 weeks after treatment. The median nerve and extrinsic finger flexors were harvested for nerve histomorphometry, myelination, muscle weight, and atrophy analyses. RESULTS: In vitro, induced MDSCs recapitulated native Schwann cell gene expression patterns and up-regulated pathways involved in neuronal growth/signaling. In vivo, green fluorescent protein-positive induced MDSCs remained stably transformed 5 weeks after injection. Induced MDSC therapy decreased muscle atrophy after median nerve injury (p = 0.0143). Induced MDSC- and MDSC-treated animals demonstrated greater functional muscle recovery when compared to untreated controls (hand grip after induced MDSC treatment: group 1, 0.91 N; group 4, 3.38 N); p < 0.0001) at 5 weeks after treatment. This may demonstrate the potential beneficial effects of MDSC therapy, regardless of differentiation stage. CONCLUSION: Both MDSCs and induced MDSCs decrease denervation muscle atrophy and improve subsequent functional outcomes after upper extremity nerve trauma in rodents.

Comminuted Distal Radius Fracture with Concomitant Median Nerve Transection: A Case Report and Literature Review.

CASE: A 41-year-old woman sustained a distal radius fracture with concomitant median nerve transection. The wound was consistent with an inside-to-outside mechanism with noted metaphyseal bone loss at the level of the median nerve injury. The median nerve was not amenable to primary repair, and given concern for inability to define the zone of the injury, the patient underwent delayed reconstruction of the nerve. CONCLUSION: A review of the literature highlights the rare incidence of this combined injury that can be undetected or misdiagnosed as an acute carpal tunnel syndrome or stretch injury to the median nerve.

Palmaris profundus in the carpal tunnel.

Carpal tunnel release is a routinely performed operation to relieve pressure caused by compression on the median nerve. In the majority of cases, the causation of the compression will be idiopathic. Among the secondary causes of median nerve compression is the palmaris profundus, a rare anatomical variant separate to the palmaris longus tendon. It has been suggested that it may cause carpal tunnel syndrome as it courses underneath the flexor retinaculum with the contents of the carpal tunnel reducing the space available to the median nerve. Several cases have found it intimately associated with the median nerve within the carpal tunnel. Raising awareness of this anatomical variant is therefore important for those undertaking carpal tunnel decompression in order to avoid unintended damage.