The anatomical relationship of the superficial radial nerve and the lateral antebrachial cutaneous nerve: A possible factor in persistent neuropathic pain

Computer assisted surgical anatomy mapping (CASAM) of the distal Posterior Interosseous Nerve (PIN) and its relation to the wrist arthroscopy portals: A cadaver study

Introduction

The distal Posterior Interosseous Nerve (PIN) plays an important part in the sensory innervation of the wrist joint. Introduction of the arthroscopy portals during wrist arthroscopy might injure the PIN. The anatomic variation in the trajectory of the PIN and the proximity to the dorsal arthroscopy portals have not yet been fully explored.

Materials and methods

Computer assisted surgical anatomy mapping (CASAM) is a technique to digitally compute and merge photographic images using anatomic landmarks and visualize variation in anatomy. A standard wrist arthroscopy procedure was carried out on eight cadaver forearms. CASAM was used to map the trajectory of the distal PIN and measure the distance to bony landmarks and the nearest wrist arthroscopy portals. Descriptive statistics were provided for anatomical measurements.

Results

CASAM illustrated great variation in the PIN trajectories between the specimens. The mean distance from the PIN to Lister's tubercle was 9 ​mm (range 3-14, SD 3.9), the distance to the ulnar styloid was 27 ​mm (range 23-32, SD 3.3). None of the nerves showed signs of iatrogenic injury from placement of the arthroscopy portals. The 3-4 portal and the 6R portal were closest to the PIN with a respective mean distance of 9 ​mm (range 4-15, SD 3.8) and 19 ​mm (range 13-22, SD 3.2).

Conclusion

CASAM demonstrated the importance of understanding nerve anatomy variations and offered insight into which arthroscopy portals are most likely to damage the distal PIN. However, we conclude that the overall risk of PIN injury from wrist arthroscopy is low due to the proximity to the portals.

The Lateral Antebrachial Neurocutaneous Flap: Case Series

BACKGROUND

The neurocutaneous flap was developed based on the understanding that every superficial cutaneous nerve includes vessels, also known as vasa nervorum or paraneural vessels, which run around and inside the nerves and deliver blood to the skin above. A cutaneous perforator connected to paraneural vessels that vascularize the skin and nerves is referred to as a neurocutaneous perforator. The lateral antebrachial cutaneous nerve (LACN), the most dependable blood supply from the primary underlying veins of the neurocutaneous flap, is the subject of this study.

METHODS

We reviewed the results of 30 flap coverage procedures in 10 children. The applied flap was based distally along the radial aspect of the hand and wrist. The pivot point of the flap was located dorsally. This study considered patients with posttraumatic tissue loss, vital structure exposure, or hand contractures with an LACN flap. There was a case-by-case assessment.

RESULTS

Thirteen male patients were included; their ages ranged from 6 to 65 years. Demographic data, preoperative cause of trauma, and postoperative complications were collected. Statistically significant improvements were observed after flap healing.

CONCLUSIONS

The LACN flap is a more versatile flap with less morbidity than other alternative flaps for coverage of soft tissue defect restoration around the hand, wrist, and distal forearm.

Ultrasound-Guided Percutaneous Cryoneurolysis of the Antebrachial Cutaneous Nerves for the Management of Prolonged Acute Post-Surgical Forearm Pain: A Report of Two Cases

Prolonged acute postsurgical pain (PAPSP) contributes to the development of chronic postsurgical pain, impaired rehabilitation, longer hospital stays, and decreased quality of life. For upper extremity analgesia, the duration of postoperative pain management with continuous brachial plexus peripheral nerve blocks is limited due to the risk of infection. Ultrasound-guided percutaneous cryoneurolysis provides extended analgesia and avoids the risks and inconveniences of indwelling catheters. We present 2 cases of PAPSP of the forearm effectively managed by the use of ultrasound-guided percutaneous cryoneurolysis to treat the medial, lateral, and posterior antebrachial cutaneous nerves.

Multidisciplinary strategies to treat painful mononeuropathies in the upper extremity: from lab to bedside

Neuropathic pain in the upper extremity is a serious problem, commonly involving relatively young patients. The pain causes loss of function and productivity, changes a patient's lifestyle and can progress into a chronic pain syndrome with secondary psychosocial co-morbidities. Treating patients with a painful mononeuropathy remains challenging, with a monodisciplinary approach often having limited treatment efficacy. This narrative review discusses how to deal with this challenge in the treatment of patients with peripheral nerve injury pain, addressing the four important pillars: (1) diagnosing a painful mononeuropathy; (2) clinical pain phenotyping; (3) personalized pain treatment; and (4) using a multidisciplinary team approach.

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.

The superficial branch of the radial nerve and sensory disturbance in the radial forearm flap donor-site

Introduction

Sensory disturbance due to injury of the superficial branch of the radial nerve (SBRN) is a donor-site morbidity of the radial forearm (RF) flap. The relationship between the SBRN preservation method and the post-operative sensation at the flap donor-site was retrospectively investigated.

Methods

We included 39 patients who underwent head and neck reconstruction with a free RF flap at Hyogo Cancer Center between April 2014 and March 2018. The patients were classified into the following three groups according to the SBRN preservation method: group 1, zero preservation, excision of the entire SBRN; group 2, main trunk preservation, excision of all branches except the main trunk of the SBRN; and group 3, complete preservation, preservation of the entire SBRN. Objective sensations and subjective symptoms at the flap donor-site were analyzed.

Results

The mean objective sensory scores were 3.18, 2.97, and 1.78 in groups 1, 2, and 3, respectively. Differences between groups 1 and 3 and between groups 2 and 3 were significant (p = 0.0035 and p = 0.037, respectively). The mean subjective symptom scores were 2.40, 1.33, and 1.40 in groups 1, 2, and 3, respectively. Differences between groups 1 and 2, and between groups 1 and 3 were significant (p = 0.032 and p = 0.019, respectively).

Conclusions

Zero preservation method had a higher risk of subjective symptoms and objective hypoesthesia development at the flap donor-site than the complete preservation method. Despite inevitable objective hypoesthesia, the main trunk preservation prevented the development of subjective symptoms. Complete preservation is optimal for RF flap harvest; however, in case of perforator crossing, main trunk preservation is another option.

Anatomical variations in the sensory innervation of the dorsal surface of the first digit space, a cadaveric study with clinical consequences

INTRODUCTION

Radial nerve palsy is a classical complication of a humeral shaft fracture. In clinical practice, motor palsy of the radial nerve is sometimes observed without an abnormality felt in the sensory territory.

HYPOTHESIS

We hypothesised that this dissociation between sensory and motor involvement is related to anatomical variations of the sensory innervation of the dorsal surface of the first digit space, thus, we decided to study the nature and frequency of these variations.

MATERIAL AND METHOD

A cadaveric study was conducted on 24 upper limbs to analyse the truncal origin of the sensory branches innervating the dorsal surface of the first digit space.

RESULTS

The sensory branch of the radial nerve (SBRN) participated in the innervation of the dorsal surface of the first digit space in 22 limbs, an anatomical variation was present in 2 cases with a mixed innervation by the SBRN and the lateral cutaneous nerve of forearm (LCNF) in 1 case and singular innervation by LCNF, with no SBRN involvement, in 1 case. Communications between SBRN and LCNF were found in 7 cases.

DISCUSSION

Pure motor radial damage, without a sensory deficit of the dorsal surface of the first digit space, does not preclude a complete traumatic injury of the radial nerve. The sensory innervation of this region can be relayed by a branch of the LCNF.

LEVEL OF EVIDENCE

IV; cadaveric study.

Computer-Assisted Surgical Anatomical Mapping of the Antebrachial Cutaneous Nerves: An Anatomical Study with a Proposition for Alternative, Cutaneous Nerve-Sparing Anterior Elbow Incisions

It is common practice to assess the distance from nerves to anatomical structures in centimeters, but patients have various body compositions and anatomical variations are common. The purpose of this study was therefore to assess the relative distance from cutaneous nerves around the elbow to surrounding anatomical landmarks by providing a stacked image that displays the average position of cutaneous nerves around the elbow. The aim was to research possibilities for adjusting common skin incisions in the anterior elbow so that cutaneous nerve injury may be avoided.

Methods

The lateral antebrachial cutaneous nerve (LABCN) and medial antebrachial cutaneous nerve (MABCN) were identified in the coronal plane around the elbow joint in 10 fresh-frozen human arm specimens. Marked photographs of the specimens were analyzed using computer-assisted surgical anatomical mapping (CASAM). Common anterior surgical approaches to the elbow joint and the distal humerus were then compared with merged images, and nerve-sparing alternatives are proposed.

Results

The arm was divided longitudinally, from medial to lateral in the coronal plane, into 4 quarters. The LABCN crossed the central-lateral quarter of the interepicondylar line (i.e., was somewhat lateral to the midline at the level of the elbow crease) in 9 of 10 specimens. The MABCN ran medial to the basilic vein and crossed the most medial quarter of the interepicondylar line. Thus, 2 of the quarters were either free of cutaneous nerves (the most lateral quarter) or contained a distal cutaneous branch in only 1 of 10 specimens (the central-medial quarter).

Conclusions

The Boyd-Anderson approach, which is often used to access anteromedial structures of the elbow, should be placed slightly further medially than traditionally advised. The distal part of the Henry approach should deviate laterally, so that it runs over the mobile wad. In distal biceps tendon surgery, the risk of cutaneous nerve injury may be reduced if a single distal incision is placed slightly more laterally (in the most lateral quarter), as in the modified Henry approach. If proximal extension is required, LABCN injury may be prevented by using the modified Boyd-Anderson incision, which runs in the central-medial quarter.

Clinical Relevance

Cutaneous nerve injury may be prevented by slightly altering the commonly used skin incisions around the elbow on the basis of the safe zones that were identified by depicting the cumulative course of the MABCN and LABCN using CASAM.

Effectiveness of surgical interventions for treating de Quervain's disease: A systematic review and meta-analysis

Introduction

This systematic review of randomized controlled trials was undertaken to assess whether any of the various currently used surgical interventions have better functional outcomes and less impairment or fewer surgical complications compared to the other common surgical interventions in de Quervain's disease.

Material and methods

Relevant studies related to surgical interventions in de Quervain's disease based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines were identified from PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials for randomized controlled trials comparing surgical interventions in de Quervain's disease published from January 2000 to December 2020. Functional outcome and impairment were the primary outcomes assessed.

Results

Three trials met the eligibility criteria which were following randomized controlled trial or quasi-experimental trial enrolling adults ≥18 years of age diagnosed with de Quervain's disease, comparing clinical outcomes between different surgical interventions, and including functional outcomes, impairment, pain and complications data. The Cochrane Risk of Bias Assessment Tool and GRADE approach were used to ascertain methodological quality. Statistical heterogeneity was tested with I-square and chi-square tests. The longitudinal skin incision probably slightly reduced superficial radial nerve injury, vein injury, scar hypertrophy, and total complications compared with the transverse skin incision with relative risk: 0.14, very low certainty by GRADE; 0.10, very low certainty by GRADE; 0.57, very low certainty by GRADE; and 0.23, very low certainty by GRADE, respectively.

Conclusion

Concerning the analysis of functional and pain scores, no significant results were able to be concluded. This study's findings must be considered in the light of quality and sample size limitations, and further high quality prospective randomized controlled clinical trials are needed to draw more firm conclusions.

Anatomical characterization of acupoint large intestine 4

Large intestine 4 (LI4) is a major acupoint used in various treatments in acupuncture and Traditional Chinese Medicine. There are structures associated within the region of LI4 that have three-dimensional anatomical relationship that needs further characterization. The aims of this study were: (a) to observe the anatomical variation of structures around LI4; (b) to observe specific overlap of structures around LI4. A 1256 mm² area was dissected in 25 cadaveric hands around LI4. Nondissected areas were marked with pins as reference points. Dissections were photographed with a fixed camera. Subsequently, images were imported to Adobe Photoshop 2020 and analyzed. Descriptive statistics and graphs were compiled using Graphpad Prism 2020. The tributaries of the dorsal venous plexus (22.3%), branches of superficial radial nerve (18.9%), first dorsal interosseous muscle (52.4%), arterial branches in the first interosseous space (10.2%), and deep ulnar nerve (4.0%) were observed in the area of LI4. One branch of the superficial radial nerve passed through LI4. The deep ulnar nerve was found in the bulk of the first dorsal interosseous muscle. Several structures observed intersected at LI4. The superficial radial nerve interweaved with the dorsal venous plexus superficially. The deep ulnar nerve passed anterior to the second palmar metacarpal artery before entering into the first dorsal interosseous muscle. These results provide anatomical evidence and variation into the vascular contributions at LI4.

Long-Term Outcomes after Surgical Treatment of Radial Sensory Nerve Neuromas: Patient-Reported Outcomes and Rate of Secondary Surgery

BACKGROUND

This study aimed to (1) describe long-term patient-reported outcomes of surgically treated symptomatic radial sensory nerve neuromas on function, pain interference, pain intensity, and satisfaction; (2) assess which factors were associated with worse function, higher pain intensity, and more pain interference; and (3) describe the secondary surgery rate and factors associated with secondary surgery.

METHODS

The authors conducted a retrospective review of patients surgically treated for radial sensory nerve neuroma from 2002 to 2016 (n = 54). Twenty-five of these 54 patients completed a follow-up survey including the Patient-Reported Outcomes Measurement Information System (PROMIS) upper extremity, pain interference, and depression scales; numerical rating scale pain and satisfaction instruments; and the global rating scale of change, at a mean period of 10.7 ± 4.3 years after neuroma surgery.

RESULTS

The mean PROMIS scores were 45.0 ± 12.1 for upper extremity, 55.5 ± 10.3 for pain interference, and 49.9 ± 10.2 for depression, and were within 1 SD of the general population. Eight patients (32 percent) reported symptoms as unchanged or worse following neuroma surgery. The median numerical rating scale pain was 3 (interquartile range, 1 to 6) and the global rating scale of change satisfaction was 10 (interquartile range, 7 to 10). Older patients (p = 0.002) and patients with higher PROMIS pain interference (p < 0.001), higher numerical rating scale for pain (p = 0.012), and lower global rating scale of change scores (p = 0.01) had worse PROMIS upper extremity scores. The secondary surgery rate was 20 percent and was associated with the presence of multiple neuromas (p = 0.001).

CONCLUSIONS

Radial sensory nerve neuromas remain difficult to treat. They have a high secondary surgery rate (20 percent), with only 68 percent of patients reporting improvement after surgical intervention. Patient-reported outcomes after surgery are similar to conditions of the general population; however, the range of outcomes is wide.

Optimal surgical approach for the treatment of Quervains disease: A surgical-anatomical study

AIM

To determine which of the common used incision techniques has the lowest chance of iatrogenic damage to the nerves which at risk are the superficial branch of the radial nerve (SBRN) and the Lateral Antebrachial Cutaneous Nerve (LABCN).

METHODS

Twenty embalmed arms were dissected and the course of the SBRN and the LABCN in each individual arm was marked and the distance between the two branches of the SBRN at the location of the First Extensor Compartment (FEC) was measured. This data was used as input in a visualization tool called Computer Assisted Anatomy Mapping (CASAM) to map the course of the nerves in each individual arm.

RESULTS

This image visualizes that in 90% of the arms, one branch of the SBRN crosses the FEC and one branch runs volar to the compartment. The distance between the two branches was 7.8 mm at the beginning of the FEC and 10.2 mm at the end. Finally the angle of incision at which the chance of damage to the nerves is lowest, is 19.4 degrees volar to the radius.

CONCLUSION

CASAM shows the complexity of the course of the SBRN over the FEC. None of the four widely used incision techniques has a significantly lower chance of iatrogenic nerve damage. Surgical skills are paramount to prevent iatrogenic nerve damage.

The novel treatment of SVF-enriched fat grafting for painful end-neuromas of superficial radial nerve

INTRODUCTION

None of the existing treatments in the management of painful end-neuromas of the superficial branch of the radial nerve (SBRN) has been proven superior due to high levels of pain relapse. Fat grafts enriched with the stromal vascular fraction (SVF) could act as a mechanic barrier with biological effects decreasing the resorption rate and boosting the graft's regenerative potential. This study describes the novel surgical treatment technique of SVF-enriched fat grafting.

PATIENTS AND METHODS

In this clinical study, five consecutive patients treated for painful end-neuromas of the SBRN between 2012 and 2013 were analyzed retrospectively. Microsurgical resection of end-neuromas followed by SVF-enriched fat grafting around the nerve stump was performed in all patients. Five different pain modalities and various predictors were compared pre- and up to 36 months postoperatively.

RESULTS

Pain reduction observed at 2 months after surgery was constant over time, though not statistically significant compared to preoperative levels. Spontaneous pain could be reduced from 1.6 ± 0.55 to 1.2 ± 1.1 (p = 0.414), spikes from 2.2 ± 1.3 to 1.4 ± 1.34 (p = 0.180), hyperaesthesia from 1.6 ± 1.14 to 1.2 ± 1.64 (p = 0.713), tap pain from 2.8 ± 0.45 to 1.8 ± 1.3 (p = 0.197) and motion pain from 2.8 ± 0.45 to 1.4 ± 1.34 (p = 0.066). An improvement in overall pain reduction could be observed from 2.2 ± 0.97 to 1.4 ± 1.26 3 years after the surgery (p = 0.104).

CONCLUSION

SVF-enriched fat grafting represents another alternative to numerous available treatments of painful end-neuromas of the SBRN. Our preliminary results could not show any significant difference in pain reduction following SVF-enriched fat grafting. Further larger trials are required in order to evaluate the therapeutic potential of SVF-enriched fat grafting.

Relation of Lateral Antebrachial Cutaneous Nerve to the Volar Approach to Distal Radius

Background: The anatomy of the lateral antebrachial cutaneous nerve (LABCN) in relation to volar approaches to the distal radius is not well visited. With the increasing popularity of distal radius fracture fixation with volar locking plates, it is prudent to study the innervation pattern of the LABCN to minimize the risk of nerve injury.

Methods: Ten cadaveric distal radial forearms were dissected to study the relationship between the LABCN, flexor carpi radialis (FCR), superficial branch of radial nerve (SBRN), and scaphoid tubercle (ST).

Results: The LABCN coursed closer to the FCR than the SBRN, with branches traversing the tendon in two specimens. The LABCN was also noted to be intimately related to the radial artery, with an average distance of the LABCN from the lateral border of FCR was 6.4mm distally and 9.6mm proximally.

Conclusions: There is a sparsely innervated corridor between the radial border of the FCR and terminal branches of the LABCN that provides safe access for volar approach to the distal radius.