Vascular supply of the radial nerve and its terminal branches: an anatomical study.

PURPOSE: The aim of this cadaveric study was to further describe the vascular supply of the radial, posterior interosseous and superficial radial nerves. METHODS: 11 cadaveric upper limbs, injected with colored latex, were dissected. Vascular afferents to the radial nerve, superficial radial nerve (SRN) and posterior interosseous nerve (PIN) were described and located. Their origin was identified and its distance to interepicondylar line was measured. RESULTS: The radial nerve had an average of 3 vascular afferents (1-5), of septomuscular origin in 54% of cases. 46% came from adjacent arteries. The PIN had an average of 8 vascular afferents (6-14), arising from septomuscular branches in 82% of cases. The PIN was vascularized in 100% of cases by a large arterial plexus originating from the supinator muscle between its two heads. The SRN had an average of 4 vascular afferents (3-7). Before crossing the septum of the brachioradialis, vascularization was predominantly septomuscular; after crossing the septum, the nerve was exclusively vascularized by septocutaneous arteries. CONCLUSION: This is the first study to describe the vascularization of the radial nerve and its terminal branches along their entire length. Our results are in line with the data available in the literature. An arterial plexus between the two heads of the supinator was surrounding the PIN in all cases. This vascular plexus might be involved in dynamic compression of the posterior interosseous nerve.

Unveiling the spiral groove: a journey through clinical anatomy, pathology, and imaging.

AIM: To review the anatomy of the spiral groove, its clinical significance, and the imaging characteristics of common pathologies affecting this area, highlighting the strengths of different imaging modalities. MATERIALS AND METHODS: A comprehensive review of the spiral groove anatomy and its clinical implications and an evaluation of various imaging techniques, including radiography, ultrasound, MRI, and CT, was conducted. The review covers pathologic conditions such as Saturday night palsy, humeral fractures, tumours, and infections, with an emphasis on their imaging findings and clinical implications. RESULTS: The spiral groove provides a pathway for the radial nerve and the deep brachial artery, both crucial for upper limb function. Each imaging modality offers unique advantages: radiography is useful for initial assessment, ultrasound provides dynamic visualisation, MRI offers high-resolution soft tissue imaging, and CT is ideal for detailed bone anatomy. Understanding these imaging characteristics is essential for diagnosing fractures, assessing humeral alignment, and detecting nerve entrapment or injury. CONCLUSION: Accurate imaging of the spiral groove is essential for diagnosing and treating pathologies related to this anatomical feature. The integrative approach of using appropriate imaging modalities enhances diagnostic precision and informs therapeutic strategies, ultimately improving patient outcomes.

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.

Ultrasound evaluation of radial nerve injuries by cortex overlapping screw tips after internal fixation of humeral fractures: a cadaveric study.

PURPOSE: The radial nerve may be painfully irritated or damaged by open reduction and internal fixation (ORIF) of humeral fractures. Secondary radial nerve lesions after ORIF of humeral shaft fractures are described in up to 16%. Not only peripheral nerves but also orthopaedic instruments and osteosynthesis material are well visible by ultrasound. The aim of this study was to evaluate the accuracy of ultrasound in assessing the relation between the bone overlapping screw tips and the radial nerve close to the humeral bone. METHODS: Ultrasound-guided drilling was used to place screws as close as possible to the radial nerve in 8 humeral bones of four cadavers. The relation between the radial nerve and the screw tips was assessed by high-resolution ultrasound, and the overlap of all screw tips over the bone was measured by ultrasound and fluoroscopy. Thereafter, the findings were validated by anatomical dissection. RESULTS: We could correctly identify all screw tips and their relation to the radial nerve by ultrasound. In 7 of 8 cases, the screw tip had direct contact with the radial nerve. The overlaying length of the screw tip was accurately measured by using ultrasound in all cases. In contrast fluoroscopy underestimated this length in 50% of cases. CONCLUSION: With this study, we show that ultrasound can reliable visualize the screw tips and its relation to the radial nerve. Ultrasound is a promising diagnostic tool to evaluate patients with radial nerve irritations or lesions after ORIF of humeral fractures. Furthermore, ultrasound could be an adequate tool to guide drilling.

The accessory brachioradialis muscle: prevalence of a rare variant with possible clinical implications.

PURPOSE: The brachioradialis muscle (BRM) belongs to the lateral group of forearm muscles and contributes to the elbow flexion. Accessory brachioradialis muscle (ABRM) or "brachioradialis accessorius" represents an uncommon BRM variant, not been enough studied. The present study investigates the prevalence of the ABRM, along with its origin, insertion, and innervation. MATERIALS: Eighty-three upper limbs were meticulously dissected at the arm, forearm, and cubital fossa to investigate the ABRM presence. When the variant muscle was identified, morphometric measurements were obtained. RESULTS: The ABRM was identified in two upper limbs (2/83, 2.4%), in a male cadaver, bilaterally. Its origin was located along with the typical BRM, and its insertion was identified into the anterior surface of the radius (proximal third). The ABRM was innervated by the radial nerve, coursing posteriorly (deeply). CONCLUSIONS: In the current study, the variant muscle was observed in 2.4%. Radial nerve compression, at the forearm, is not an uncommon entrapment neuropathy. The relationship between the radial nerve and the ABRM could precipitate radial neuropathy.

Intraneural Nodular Fasciitis of the Radial Nerve: A Case Report.

CASE: We report a case of intraneural nodular fasciitis in the forearm initially suspected as a schwannoma, emphasizing the importance of accurate diagnosis. A 40-year-old woman presented with mass on the lateral aspect of her right forearm and radial neuropathy symptoms for 2 months. An excisional biopsy and histopathological examination confirmed nodular fasciitis. Postoperative evaluation at 4.5 years found no pain, paralysis, or recurrence. CONCLUSION: Awareness of nodular fasciitis is crucial to prevent misdiagnosis and unnecessary treatment. Despite its rapid growth, nodular fasciitis generally has an excellent prognosis without long-term consequences.

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.

[Anatomical cartography of the radial nerve at the elbow level for intraradial nerve transfers for finger extension reconstruction in spastic upper limb - A cadaveric study]. / Cartographie anatomique du nerf radial dans la région du coude pour son application aux transferts nerveux intraradiaux dans la chirurgie de la spasticité.

INTRODUCTION: Upper limb spasticity is a surgical challenge, both in diminishing agonists spasticity and reconstructing antagonist function. Brachioradialis (BR) is often involved in elbow flexors spasticity. Finger extension is often impaired in spastic patients. This study aims to demonstrate the feasibility of BR motor branch to posterior interosseous nerve (PIN) during BR selective neurectomies, and to describe fascicles topography inside the radial nerve to facilitate PIN dissection. MATERIAL AND METHOD: Ten upper limbs from 10 fresh frozen anatomical specimens were dissected. Motor branches to the BR, wrist extensors, supinator, PIN and radial sensory branch were identified. BR to PIN transfer was realized and its feasibility was studies (donor length, tensionless suture). RESULTS: BR to PIN transfer was achievable in 9 out of 10 cases. The position of the sensory branch of the radial nerve was inferior or medial in all cases. The position of the PIN was lateral in 90% of the cases. CONCLUSION: BR to PIN nerve transfer is achievable in most cases (90%). The lateral topography of the PIN and the inferomedial topography of the sensory branch in most cases allows for an easier intraoperative finding of the PIN when stimulation is not possible. LEVEL: IV, feasibility study.

Superficial Branch of the Radial Nerve Versus Sural Nerve Grafting After Traumatic Adult Brachial Plexus Injury.

The purpose of this study was to compare two sources of nerve graft for brachial plexus reconstruction: the denervated superficial branch of the radial nerve (SBRN) and the sural nerve. Ninety-seven patients who underwent brachial plexus reconstruction with denervated SBRN nerve (24 patients with 24 grafts) or with sural nerve grafting (73 patients with 83 nerve grafts) were included. The two groups were compared with respect to postoperative muscle reinnervation, disabilities of the arm, shoulder, and hand (DASH) scores. In the SBRN group, only four (17%) of the nerve grafts provided grade III or higher muscle function. In the sural nerve group, 31 (37%) of the nerve grafts provided grade III or higher muscle function. Smoking had a negative impact on muscle recovery. Denervated SBRN grafts are associated with inferior outcomes when compared with sural nerve grafts in the treatment of traumatic adult brachial plexus injuries. (Journal of Surgical Orthopaedic Advances 33(2):080-083, 2024).

Systematic review of humeral shaft fracture (OTA/AO 12) complicated with iatrogenic radial nerve injury.

OBJECTIVES: To compare the iatrogenic radial nerve injury (iRNI) rate of different implant (plate vs. intramedullary nail) and surgical approaches during humeral shaft fracture surgery. METHODS: The online PubMed database was used to search for articles describing iRNI after humeral fracture with a publication date from Jan 2000 to October 2023. The following types of articles were selected: (1) case series associating with adult humeral shaft fracture, preoperative radial nerve continuity, non-pathological fracture and non-periprosthetic fracture; (2) involving humeral shaft (OTA/AO 12) fractures. Articles where we were unable to judge surgical approach or fracture pattern (OTA/AO 12) were excluded. The data were analyzed by SPSS 27.0 and Chi-square test was performed to identify incidence of iRNI associated with different implant and surgical approaches. RESULTS: Fifty-four articles with 5063 cases were included, with 3510 cases of the plate, 830 cases of intramedullary nail and 723 cases of uncertain internal fixation. The incidences of iRNI with plate and intramedullary nail were 5.95% (209/3510) and 2.77% (23/830) (p < 0.05). And iRNI incidences of different surgical approaches were 3.7% (3/82) for deltopectoral approach, 5.74% (76/1323) for anterolateral approach, 13.54% (26/192) for lateral approach and 6.68% (50/749) for posterior approach. The iRNI rates were 0.00% (0/33) for anteromedial MIPO, 2.67% (10/374) for anterolateral MIPO and 5.40% (2/37) for posterior MIPO (p > 0.05). The iRNI rates were 2.87% (21/732) for anterograde intramedullary nail and 2.04% (2/98) for retrograde intramedullary nail (p > 0.05). In humeral bone nonunion surgery, the rate of iRNI was 15.00% (9/60) for anterolateral approach, 16.7% (2/12) for lateral approach and 18.2% (6/33) for posterior approach (p > 0.05). CONCLUSION: Intramedullary nailing is the preferred method of internal fixation for humeral shaft fractures that has the lowest rate of iRNI. Compared with anterolateral and posterior approaches, the lateral surgical approach had a higher incidence of iRNI. The rate of iRNI in MIPO was lower than that in open reduction and internal fixation. LEVEL OF EVIDENCE: Level IV.

Rare Variant of the Radial Artery Causing Compression of the Superficial Radial Nerve: A Case Report.

CASE: This case report describes a patient with paresthesia in the distribution of the superficial sensory branch of the radial nerve that was treated with surgery. Intraoperatively, there was a unique cause of internal compression by a rare superficial radial artery variant running adjacent to it. The nerve was mobilized from the artery with fascial releases. The patient had symptom resolution postoperatively. CONCLUSION: To our knowledge, this cause of compression has not been described before and should be considered in a differential diagnosis. In addition, clinicians should be aware of this anatomical variant during venipunctures and surgical approaches.

Assessing the Influence of Nonischemic A-Fiber Conduction Blockade on Offset Analgesia: An Experimental Study.

Offset analgesia (OA) is believed to reflect the efficiency of the endogenous pain modulatory system. However, the underlying mechanisms are still being debated. Previous research suggested both, central and peripheral mechanisms, with the latter involving the influence of specific A-delta-fibers. Therefore, this study aimed to investigate the influence of a nonischemic A-fiber conduction blockade on the OA response in healthy participants. A total of 52 participants were recruited for an A-fiber conduction blockade via compression of the superficial radial nerve. To monitor fiber-specific peripheral nerve conduction capacity, quantitative sensory testing was performed continuously. Before, during, and after the A-fiber block, an individualized OA paradigm was applied to the dorsum of both hands (blocked and control sides were randomized). The pain intensity of each heat stimulus was evaluated by an electronic visual analog scale. A successful A-fiber conduction blockade was achieved in thirty participants. OA has been verified within time (before, during, and after blockade) and condition (blocked and control side) (P < .01, d > .5). Repeated measurements analysis of variance showed no significant interaction effects between OA within condition and time (P = .24, η²p = .05). Hence, no significant effect of A-fiber blockade was detected on OA during noxious heat stimulation. The results suggest that peripheral A-fiber afferents may play a minor role in OA compared with alternative central mechanisms or other fibers. However, further studies are needed to substantiate a central rather than peripheral influence on OA. PERSPECTIVE: This article presents the observation of OA before, during, and after a successful A-fiber conduction blockade in healthy volunteers. A better understanding of the mechanisms of OA and endogenous pain modulation, in general, may help to explain the underlying aspects of pain disorders.

Anatomical study of the safety corridor for bridge plating positioned on the lateral border of the humerus.

PURPOSE: This study shows the danger zone and the safety corridor in the lateral approach with bridge plating by measuring the distance between the lateral side of the plate positioned on the lateral aspect of the humerus and the radial nerve after it pierces the lateral intermuscular septum, in the different forearm positions. METHODS: Forty arms of 20 human cadavers were used, the radial nerve was identified and marked on the lateral surface the radial nerve at the exit of the lateral intermuscular septum and anteriorisation of the nerve in relation to the humeral shaft and the lateral epicondyle was also marked. The distances were measured with a digital caliper. A submuscular extraperiosteal corridor was created, proximally between the biceps brachialis and deltoid muscle and distally between the triceps and brachioradialis muscle, followed by the positioning of the low contact large fragments contoured plate with 14 combined holes (fixed and cortical angle), inserted from distal to proximal. Measurements were performed in four positions (elbow flexion with forearm pronation, elbow flexion with forearm supination, elbow extension with forearm pronation and elbow extension with forearm supination). RESULTS: Significant statistical differences occurred with the different positions, and the elbow flexion with forearm supination was shown to be the position that provides the safest submuscular extraperiosteal corridor in a lateral approach of the humerus. CONCLUSION: The danger zone of radial nerve is an area that extends from 15 cm to 5 cm proximal to the lateral epicondyle and the safest way to create a submuscular and extraperiosteal corridor in the lateral region of the humerus is with the elbow in flexion and the forearm in supination.

In cases of humeral diaphyseal fractures, is lateral approach surgery without radial nerve exploration as effective and safe as conventional surgery?

BACKGROUND: This study compares the efficacy and safety of lateral approach surgery with and without radial nerve dissection in treating humeral diaphyseal fractures. It assesses clinical, radiological, and complication outcomes, providing a description of the surgical methods and perioperative benefits. METHODS: We retrospectively analyzed data from 71 patients admitted between May 2015 and December 2022 who underwent lateral approach surgery for humeral diaphyseal fractures. Group 1, consisting of 34 patients without radial nerve dissection, and Group 2, comprising 37 patients with radial nerve dissection, were compared. Parameters such as age, gender, fracture side (right/left), fracture type, follow-up time, surgical duration, blood loss, radiological and clinical evaluations (including Shoulder-Elbow range of motion [ROM] and Quick Disabilities of the Arm, Shoulder, and Hand score [Q-DASH]), and complications were examined. Surgical techniques and outcomes were documented. RESULTS: Both groups exhibited comparable distributions in age, gender, fracture types, and follow-up times (p>0.05). Group 1 demonstrated significantly lower surgical duration and blood loss compared to Group 2 (p<0.05 for both). Clinical assessment revealed satisfactory shoulder and elbow ROM within functional limits for all patients, with no instances of infection. Q-DASH scores were similar between groups. Postoperative radial nerve palsy occurred in one patient in Group 1 and three patients in Group 2, with all cases resolving uneventfully during outpatient follow-ups. Radiological assessment confirmed uneventful union in all patients. CONCLUSION: Lateral approach surgery without radial nerve dissection for humeral diaphyseal fractures offers comparable effectiveness and safety to conventional surgery, with potential perioperative advantages such as reduced operation time and blood loss.

Superficial thrombophlebitis in the forearm leading to entrapment of the radial nerve branch: a first case report and literature review.

This article reports a case of a female patient admitted with swelling and subcutaneous mass in the right forearm, initially suspected to be multiple nerve fibroma. However, through preoperative imaging and surgery, the final diagnosis confirmed superficial thrombophlebitis. This condition resulted in entrapment of the radial nerve branch, leading to noticeable nerve entrapment and radiating pain. The surgery involved the excision of inflammatory tissue and thrombus, ligation of the cephalic vein, and complete release of the radial nerve branch. Postoperative pathology confirmed the presence of Superficial Thrombophlebitis. Through this case, we emphasize the importance of comprehensive utilization of clinical, imaging, and surgical interventions for more accurate diagnosis and treatment. This is the first clinical report of radial nerve branch entrapment due to superficial thrombophlebitis.

Ultra high-frequency ultrasound of fascicles in the ulnar and radial nerves.

INTRODUCTION/AIMS: Ultra high-frequency ultrasound (UHFUS) has been demonstrated to allow easy visualization and quantification of median and digital nerve fascicles; however, there is a lack of normative data for other upper limb nerves. The purpose of this study was to use UHFUS to establish normative reference values and ranges for fascicle count and density within selected upper extremity nerves. METHODS: Twenty-one healthy volunteers underwent sonographic examination of the ulnar, superficial branch of the radial, and radial nerves on one upper limb using UHFUS with a 48 MHz linear transducer. The number of fascicles in each peripheral nerve and fascicle density were assessed. RESULTS: The mean fascicle number and fascicle density for each of the measured nerves was ulnar nerve at the wrist 11.7 and 2.0, ulnar nerve at the elbow 9.2 and 1.1, superficial branch of the radial nerve 7.3 and 2.5, and radial nerve at the spiral groove 4.2 and 0.8. A single significant association was observed between CSA and fascicle number in the ulnar nerve at the wrist (p = .023, r = 0.66). Neither fascicle number nor density could be predicted by age, sex, height, weight, or body mass index. DISCUSSION: UHFUS may help to establish a baseline of normative data on upper limb nerves that are not frequently biopsied due to their mixed motor and sensory functions and has the potential for increased understanding of nerve fascicular anatomy to improve diagnostic accuracy of focal nerve lesions, particularly those with selective fascicular involvement.

Radial Nerve Palsy in the Setting of Humeral Shaft Fracture.

The upper limb has a complex anatomy comprised of many nerve and vascular structures, making humeral shaft fractures extremely important. Injury to the humeral shaft commonly occurs due to trauma and affects younger male or older female patients. The radial nerve travels along the spiral groove of the humerus, placing it at an increased risk of damage in humeral shaft fractures. If injured, there are a variety of classifications of radial nerve injury, different indications for exploration, and treatment methods that orthopedic surgeons have available in treating these injuries. This review aims to discuss the etiology of humeral shaft fracture-associated radial nerve palsy, tools for diagnosis, and treatment.

Superficial branch of the radial nerve regularly contains fibers from the lateral antebrachial cutaneous nerve: A role in neuroma treatment.

BACKGROUND: Many surgical strategies aim to treat the symptomatic neuroma of the superficial branch of the radial nerve (SBRN). It is still difficult to treat despite many attempts to reveal a reason for surgical treatment failure. The lateral antebrachial cutaneous nerve (LACN) is known to overlap and communicate with SBRN. Our study aims to determine the frequency of spreading of LACN fibers into SBRN branches through a microscopic dissection to predict where and how often LACN fibers may be involved in SBRN neuroma. METHODS: Eighty-seven cadaveric forearms were thoroughly dissected. The path of LACN fibers through the SBRN branching was ascertained using microscopic dissection. Distances between the interstyloid line and entry of LACN fibers into the SBRN and emerging and bifurcation points of the SBRN were measured. RESULTS: The LACN fibers joined the SBRN at a mean distance of 1.7 ± 2.5 cm proximal to the interstyloid line. The SBRN contained fibers from the LACN in 62% of cases. Most commonly, there were LACN fibers within the SBRN's third branch (59%), but they were also observed within the first branch, the second branch, and their common trunk (21%, 9.2%, and 22%, respectively). The lowest rate of the LACN fibers was found within the SBRN trunk (6.9%). CONCLUSION: The SBRN contains LACN fibers in almost 2/3 of the cases, therefore, the denervation of both nerves might be required to treat the neuroma. However, the method must be considered based on the particular clinical situation.