Superficial Radial Nerve Research Articles

Surgical approach for elastic stable intramedullary nail in pediatric radius shaft fracture: a systematic review.

When using elastic stable intramedullary nailing in children's distal radius shaft fractures, the surgical approach can either be lateral or dorsal. The aim of this article was to carry out a systematic review of the literature comparing the two types of approaches in terms of complications. An electronic search of databases was performed. Titles of articles were screened, and abstracts and full text were read. Data were extracted in terms of demographics and complications. The dorsal approach had a 2.6% rate of extensor pollicis longus tendon rupture, whereas the lateral approach had a 2.9% rate of transient superficial radial nerve palsy and 0.3% rate of permanent damage. These complications should be considered when deciding between the two surgical approaches.

"In Situ Vascular Nerve Graft" for Restoration of Intrinsic Hand Function: An Anatomical Study.

In combined high median and ulnar nerve injury, transfer of the posterior interosseous nerve branches to the motor branch of the ulnar nerve (MUN) is previously described in order to restore intrinsic hand function. In this operation a segment of sural nerve graft is required to close the gap between the donor and recipient nerves. However the thenar muscles are not innervated by this nerve transfer. The aim of the present study was to evaluate whether the superficial radial nerve (SRN) can be used as an "in situ vascular nerve graft" to connect the donor nerves to the MUN and the motor branch of median nerve (MMN) at the same time in order to address all denervated intrinsic and thenar muscles. Twenty fresh male cadavers were dissected in order to evaluate the feasibility of this modification of technique. The size of nerve branches, the number of axons and the tension at repair site were evaluated. This nerve transfer was technically feasible in all specimens. There was no significant size mismatch between the donor and recipient nerves Conclusions: The possible advantages of this modification include innervation of both median and ulnar nerve innervated intrinsic muscles, preservation of vascularity of the nerve graft which might accelerate the nerve regeneration, avoidance of leg incision and therefore the possibility of performing surgery under regional instead of general anesthesia. Briefly, this novel technique is a viable option which can be used instead of conventional nerve graft in some brachial plexus or combined high median and ulnar nerve injuries when restoration of intrinsic hand function by transfer of posterior interosseous nerve branches is attempted.

Effect of Fascia Penetration on Sensory Nerve Conduction in the Superficial Radial Nerve.

The aim of this study was to identify the effects of fascia penetration on superficial radial sensory nerve action potential amplitude. The penetration point (PP) at which the nerve penetrated the brachioradialis fascia and became superficial was observed using ultrasonography. The sensory nerve action potential amplitude was measured at five points: the penetration point, 2 and 4 cm proximal to the PP, and 2 and 4 cm distal to the PP. The sensory nerve action potential amplitude at the penetration point and at 2 and 4 cm distal to the PP was significantly larger than that at 2 and 4 cm proximal to the PP. The largest amplitude was obtained 2 cm distal to the PP. The sensory nerve action potential of the superficial radial nerve changes significantly around the fascia penetration point.

Effects of wrist position on reciprocal inhibition and cutaneous reflex amplitudes in forearm muscles

In the leg, amplitudes of cutaneous reflexes and reciprocal inhibition are significantly affected by joint and limb position. Comparatively little is known about such modulation in the arm. In this study, amplitudes of reciprocal inhibition (from median nerve stimulation near elbow) and cutaneous reflexes (from median or superficial radial nerve stimulation at the wrist) were measured in forearm muscle extensor carpi radialis with the hand pronated or neutral during graded voluntary activation. Significant correlations with muscle activation were found for reciprocal inhibition and cutaneous reflex amplitudes at both positions. Only cutaneous reflexes from superficial radial nerve were modulated by wrist position. This study reveals that effect of limb position is nerve-specific in cutaneous reflexes and not significant on reciprocal inhibition in the arm. This has implications for measurement and study design in those who have mobility and motor activation challenges (e.g. neurotrauma) that affect hand function.

Effects of a compression garment on sensory feedback transmission in the human upper limb.

Compression apparel is popular in both medical and sport performance settings. Perceived benefits are suggested to include changes in sensory feedback transmission caused by activation of mechanoreceptors. However, little is known about effects of compression apparel on sensorimotor control. Our purpose was to mechanistically examine whether compression apparel modulates sensory feedback transmission and reaching accuracy in the upper limb. Two experiments were completed under CONTROL and COMPRESSION (sleeve applied across the elbow joint) conditions. M-waves and H-reflexes were elicited by stimulating the median nerve and were recorded via surface electromyography (EMG). In experiment 1, H-reflexes and M-H recruitment curves were assessed at REST, during wrist flexion (10% EMGmax), and during a cutaneous conditioning of the superficial radial (SR) or distal median (MED) nerve. Cutaneous reflexes were elicited during 10% wrist flexion via stimulation of SR or MED. In experiment 2, unconditioned H-reflex measures were assessed at rest, during arm cycling, and during a discrete reaching task. Results indicate that compression apparel modulates spinal cord excitability across multiple sensory pathways and movement tasks. Interestingly, there was a significant improvement in reaching accuracy while wearing the compression sleeve. Taken together, the compression sleeve appears to increase precision and sensitivity around the joint where the sleeve is applied. Compression apparel may function as a "filter" of irrelevant mechanoreceptor information allowing for optimal task-related sensory information to enhance proprioception. NEW & NOTEWORTHY Wearing a customized compression sleeve was shown to alter the excitability of multiple pathways within the central nervous system regardless of conditioning input or movement task and was accompanied by improved accuracy of reaching movements and determination of movement end point. Compression apparel may assist as a type of "filter function" of tonic and nonspecific mechanoreceptor information leading to increased precision and movement sensitivity around the joint where compression is applied.

Complications of treating distal radius fractures with external fixation: A community experience

Objective: To analyze the immediate postoperative complications associated with treating distal radius fractures with external fixation. Design: A retrospective chart review of data obtained from 24 consecutive patients who were treated with small AO external fixators in 1997. Setting: Two community medical centers. Intervention: Preoperative and postoperative radiograph measurements were taken of radial inclination, radial tilt, and radial length, and fractures were classified according to the AO system. Patient charts were reviewed to document demographics, type of fixator used, open or percutaneous technique for pin placement, use of augmentation, additional operations, and complications. Main outcome measurements: Complications associated with treating distal radius fractures with one type of external fixator. Results: Sixteen of the 24 patients had complications: 5 with neuropathies of the median or superficial radial nerve, 9 with pin track infections, 2 with pin loosening, one with a nonunion, 2 with malunion, and 4 patients each with radial shortening, loss of radial tilt, collapse of ulnar border or volar intercalated segment instability (VISI) of the lunate and rotatory subluxation of the scaphoid. Conclusions: Postoperative complications following distal radius fractures treated with external fixation are common. Their effect, however, on long term functional results and patient satisfaction is negligible, with the exception of those patients with complications intrinsic to the fracture itself, i.e., nonunion, malunion or carpal malalignment.

Intralimb and Interlimb Cutaneous Reflexes during Locomotion in the Intact Cat.

When the foot contacts an obstacle during locomotion, cutaneous inputs activate spinal circuits to ensure dynamic balance and forward progression. In quadrupeds, this requires coordinated reflex responses between the four limbs. Here, we investigated the patterns and phasic modulation of cutaneous reflexes in forelimb and hindlimb muscles evoked by inputs from all four limbs. Five female cats were implanted to record muscle activity and to stimulate the superficial peroneal and superficial radial nerves during locomotion. Stimulating these nerves evoked short-, mid-, and longer-latency excitatory and/or inhibitory responses in all four limbs that were phase-dependent. The largest responses were generally observed during the peak activity of the muscle. Cutaneous reflexes during mid-swing were consistent with flexion of the homonymous limb and accompanied by modification of the stance phases of the other three limbs, by coactivating flexors and extensors and/or by delaying push-off. Cutaneous reflexes during mid-stance were consistent with stabilizing the homonymous limb by delaying and then facilitating its push-off and modifying the support phases of the homolateral and diagonal limbs, characterized by coactivating flexors and extensors, reinforcing extensor activity and/or delaying push-off. The shortest latencies of homolateral and diagonal responses were consistent with fast-conducting disynaptic or trisynaptic pathways. Descending homolateral and diagonal pathways from the forelimbs to the hindlimbs had a higher probability of eliciting responses compared with ascending pathways from the hindlimbs to the forelimbs. Thus, in quadrupeds, intralimb and interlimb reflexes activated by cutaneous inputs ensure dynamic coordination of the four limbs, producing a whole-body response.SIGNIFICANCE STATEMENT The skin contains receptors that, when activated, send inputs to spinal circuits, signaling a perturbation. Rapid responses, or reflexes, in muscles of the contacted limb and opposite homologous limb help maintain balance and forward progression. Here, we investigated reflexes during quadrupedal locomotion in the cat by electrically stimulating cutaneous nerves in each of the four limbs. Functionally, responses appear to modify the trajectory or stabilize the movement of the stimulated limb while modifying the support phase of the other limbs. Reflexes between limbs are mediated by fast-conducting pathways that involve excitatory and inhibitory circuits controlling each limb. The comparatively stronger descending pathways from cervical to lumbar circuits controlling the forelimbs and hindlimbs, respectively, could serve a protective function.

Outcome of Stromal Vascular Fraction-Enriched Fat Grafting Compared to Intramuscular Transposition in Painful End-Neuromas of Superficial Radial Nerve: Preliminary Results.

The management of painful end-neuromas of the superficial branch of the radial nerve (SBRN) remains challenging due to high levels of pain relapse. The novel technique of stromal vascular fraction (SVF)-enriched fat grafting showed continuous pain relief, although failed to prove statistically significant. Besides acting as a mechanical barrier, SVF-enriched fat grafting might also affect the cellular level. The aim of this study was to compare clinical outcomes of SVF to the widely popular intramuscular transposition technique. In this cohort study, 10 consecutive patients treated for painful end-neuromas of the SBRN between 2010 and 2013 were analyzed retrospectively. Microsurgical resection of end-neuromas was performed in all patients. Five patients were treated with subsequent intramuscular transposition into the brachioradialis muscle and five patients received SVF-enriched fat grafting. Five different pain modalities and various predictors were compared pre- and up to 36 months post-operatively. In the transposition group, sustained pain reduction was not observed after an initial significant reduction 2 months' post-surgery, resulting in pain relapse at 36 months and comparable to the preoperative assessment. In the graft group, some degree of pain reduction was observed at 2 months after the surgery and proved to be constant in the long-term outcome, although not statistically significant compared to preoperative levels. Both SVF-enriched fat grafting and intramuscular transposition failed to prove statistical significant pain reduction in treating symptomatic neuromas of peripheral nerves.

Rhythmic arm cycling training improves walking and neurophysiological integrity in chronic stroke: the arms can give legs a helping hand in rehabilitation.

Training locomotor central pattern-generating networks (CPGs) through arm and leg cycling improves walking in chronic stroke. These outcomes are presumed to result from enhanced interlimb connectivity and CPG function. The extent to which rhythmic arm training activates interlimb CPG networks for locomotion remains unclear and was assessed by studying chronic stroke participants before and after 5 wk of arm cycling training. Strength was assessed bilaterally via maximal voluntary isometric contractions in the legs and hands. Muscle activation during arm cycling and transfer to treadmill walking were assessed in the more affected (MA) and less affected (LA) sides via surface electromyography. Changes to interlimb coupling during rhythmic movement were evaluated using modulation of cutaneous reflexes elicited by electrical stimulation of the superficial radial nerve at the wrist. Bilateral soleus stretch reflexes were elicited at rest and during 1-Hz arm cycling. Clinical function tests assessed walking, balance, and motor function. Results show significant changes in function and neurophysiological integrity. Training increased bilateral grip strength, force during MA plantarflexion, and muscle activation. "Normalization" of cutaneous reflex modulation was found during arm cycling. There was enhanced activity in the dorsiflexor muscles on the MA side during the swing phase of walking. Enhanced interlimb coupling was shown by increased modulation of MA soleus stretch reflex amplitudes during arm cycling after training. Clinical evaluations showed enhanced walking ability and balance. These results are consistent with training-induced changes in CPG function and interlimb connectivity and underscore the need for arm training in the functional rehabilitation of walking after neurotrauma. NEW & NOTEWORTHY It has been suggested but not tested that training the arms may influence rehabilitation of walking due to activation of interneuronal patterning networks after stroke. We show that arm cycling training improves strength, clinical function, coordination of muscle activity during walking, and neurological connectivity between the arms and the legs. The arms can, in fact, give the legs a helping hand in rehabilitation of walking after stroke.

The course of the radial nerve in the distal humerus: A novel, anatomy based, radiographic assessment.

Iatrogenic nerve injury during fracture surgery of the upper arm is a well-known complication. Prevention of this type of injuries would be of great value. The literature describes several methods to reduce this type of injury, but no perfect solution is at hand. In this study we introduce a new radiographic evaluation of the course and variation of the radial nerve in the distal part of the humerus in relation to bony landmarks as observed on a plain (trauma) radiographs. Aim of this new approach is to reduce the chance of iatrogenic nerve injury by defining of a danger zone in the distal upper arm regarding the radial nerve and hence give an advise for future implant fabrication.Methods and findingsMeasurements were done on both arms of ten specially embalmed specimens. Arms were dissected and radiopaque wires attached to the radial nerve in the distal part of the upper arm. Digital radiographs were obtained to determine the course of the radial nerve in the distal 20 cm of the humerus in relation to bony landmarks; medial epicondyle and capitellum-trochlea projection (CCT). Analysis was done with ImageJ and Microsoft Excel software. We also compared humeral nail specifications from different companies with the course of the radial nerve to predict possible radial nerve damage.ResultsThe distance from the medial epicondyle to point where the radial nerve bends from posterior to lateral was 142 mm on AP radiographs and 152 mm measured on the lateral radiographs. The average distance from the medial epicondyle to point where the radial nerve bends from lateral to anterior on AP radiographs was 66 mm. On the lateral radiographs where the nerve moves away from the anterior cortex 83 mm to the center of capitellum and trochlea (CCT). The distance from the bifurcation of the radial nerve into the posterior interosseous nerve (PIN) and superficial radial nerve was 21 mm on AP radiographs and 42 mm on the lateral radiographs (CCT).ConclusionsThe course of the radial nerve in the distal part of the upper arm has great variety. Lateral fixation is relatively safe in a zone between the center of capitellum-trochlea and 48 mm proximal to this point. The danger zone in lateral fixation is in-between 48–122 mm proximal from CCT. In anteroposterior direction; distal fixation is dangerous between 21–101 mm measured from the medial epicondyle. The more distal, the more medial the nerve courses making it more valuable to iatrogenic damage. The IMN we compared with our data all show potential risk in case of (blind) distal locking, especially from lateral to medial direction.

Nerve transfer to relieve pain in upper brachial plexus injuries: Does it work?

ObjectivesPatients with C5 and C6 nerve root avulsion may complain from pain. For these patients, end-to-side nerve transfer of the superficial radial nerve into the median nerve is suggested to relieve pain. Patients and MethodsEleven patients (with a primary brachial plexus reconstruction) undergoing end-to-side nerve transfer of the superficial radial nerve into the ulnovolar part of the median nerve were assessed. Pain before surgery was compared to that at 6-month follow-up using visual analog scale (VAS) scores. ResultsA significant difference was seen between the mean VAS before (8.5) and after surgery (0.7) (P=0.0). After the six-month follow-up, 6 patients felt no pain according to VAS, notwithstanding 5 patients with a mild pain. ConclusionThe evidence from the present study suggests that end-to-side nerve transfer of the superficial radial nerve into the ulnovolar part of the median nerve is an effective technique in reducing pain in patients with C5 and C6 nerve root avulsion.

Nerve conduction study for diagnosing injury in the superficial radial nerve

Background: The superficial radial nerve (SRN) is vulnerable to accidental or iatrogenic injures. The nerve bifurcates into the medial and lateral branches. The medial branch innervates the sensory skin of the dorsomedial thumb side and radial hand and finger side, while the lateral branch innervates the dorsolateral thumb side.

Preoperative Computer Simulation and Patient-specific Guides are Safe and Effective to Correct Forearm Deformity in Children.

Posttraumatic and congenital forearm deformities in children can be difficult to appreciate in all planes. In cases of distal radioulnar joint instability and loss of forearm rotation, surgical correction is challenging. Advances in 3-dimensional printing allow creation of custom guides at a reasonable cost, enabling precise correction of the deformity in all planes. Nineteen children with deformity of the forearm had corrective osteotomies performed using preoperative 3-dimensional computer modeling and patient-specific surgical guides. Surgicase software was used for 3-dimensional planning of the corrective osteotomy, by superimposing a mirror image of the unaffected side as a template. Based upon this planning, patient-specific surgical guides were manufactured. Radiographic and clinical outcomes were assessed. Three patients had a diagnosis of multiple hereditary exostoses, and one of Madelung's deformity. The remaining 15 patients had a diagnosis of fracture malunion. Average preoperative angulation of both the radius and ulna was 23 degrees. For the patients with fracture malunions, the time from injury to surgery ranged from 6 months to 8 years. Twelve patients underwent osteotomies of both the radius and ulna, 5 had osteotomies of the radius alone, and 2 had a single osteotomy of the ulna only. All osteotomies went on to unite and no patient lost range of motion. Preoperative arc of forearm rotation averaged 101 degrees (range 0 to 180 degrees). Postoperatively, this improved to 133 degrees (range 85 to 180 degrees). Eight patients had distal radioulnar instability preoperatively, all of which normalized after surgery. There were 4 complications: 1 hypertrophic scar, 1 subject with extensor pollicis longus weakness, and 2 transient sensory losses in the superficial radial nerve distribution. This case series demonstrates that 3-dimensional computer modeling permits complex and multiple osteotomies to be done safely to achieve deformity correction in children. Limitations in forearm rotation and distal radioulnar malalignment can be reliably improved using this technique. Level IV-retrospective case series.

All-Endoscopic Distal Biceps Repair: Cadaveric Portal Safety Analysis and Technical Feasibility Using 2 Fixation Techniques

The 2-part cadaveric study evaluated portal placement sites for distal biceps endoscopic repair. Technical feasibility and safety of an all-endoscopic repair using 2 fixation techniques (4 devices) was assessed. The study demonstrates the cadaveric anatomy-at-risk and presents guidelines for safe endoscopy in the cubital fossa and upper forearm region. Distal biceps tendon (DBT) injuries often require surgical intervention. Current treatment strategies use open surgical approaches to debride and repair the tendon. Endoscopic techniques have been suggested, however, the safety and feasibility of performing an endoscopic procedure in the upper forearm has not been evaluated. The purpose of this study was (1) to determine safe portal placement sites for endoscopy in the upper forearm, and (2) to analyze the feasibility and safety of performing an all-endoscopic repair of the ruptured distal biceps tendon using 2 fixation techniques (Button, suture anchors). The hypothesis of this study was that all-endoscopic DBT repair was possible without injury to neurovascular structures. 35 fresh frozen cadavers were used in 2 groups. In the first part of the study, 10 fresh frozen cadavers were used to analyze 5 possible portal sites (Parabiceps portal, two distal anterior portals [DAP 1 and DAP 2], tuberosity portal, and distal posterior portal) for distal biceps endoscopy. Nine neurovascular structures (cephalic vein; lateral cutaneous nerve; leash of vessels; radial nerve; superficial radial nerve; posterior interosseous nerve; radial artery; brachial artery; median nerve) were dissected, and their distances from portal sites were measured. In the second part, 25 fresh frozen cadaveric elbows were used. An endoscopic technique was used to explore the normal distal biceps and cubital fossa. The DBT was sectioned at the radial tuberosity. The tendon was then endoscopically reattached to the tuberosity using (1) button technique, with and without interference screw (15 cadaveric elbows), and (2) dual suture-anchor technique with 2 anchor types (10 cadaveric elbows). At the end of the procedure, each cadaver was dissected and nine neurovascular structures were assessed for injury. In addition, analysis of footprint of repaired DBT was performed, and placement site of fixation devices was evaluated. Compartmental pressures were obtained before and after procedure. In the first part (10 cadavers): parabiceps and distal posterior portals were safe. Radial artery was significantly ‘‘at risk’’ of injury from tuberosity portal. Similarly, superficial radial nerve (SRN) was ‘‘at risk’’ from the distal anterior portal 2, and the posterior interosseous nerve (PIN) was ‘‘at risk’’ from distal anterior portal (DAP 1). Overall, RA, SRN, and PIN were found to be significantly'' at risk'' (p<0.05). In the second part (25 cadavers): The normal and sectioned tendons, and the anterior and medial aspects of the tuberosity were clearly visualized via the parabiceps portal. Endoscopic repair was possible using all fixation devices. Neurovascular structures were at low risk for injury. A small rise in compartment pressures was noted before and after the procedure. Gapping and contact area varied between the different fixation devices. Endoscopic reattachment of the sectioned DBT was safe and feasible using all fixation devices. Parabiceps and distal posterior portals were safe, However, other 3 anterior portals were significantly closer to neurovascular structures, and open dissection is recommended if these portals are used. RA, SRN, and PIN were significantly ‘‘at risk’’ as compared to other structures amongst the portals studied.

Post-operative Complications Following Distal Biceps Tendon Repairs: A Prospective Study

Ownership Interest: Matador Medical, Dimension Orthotics LLC, Wright Medical (Beredjiklian) The reported incidence of post-operative complications following distal biceps tendon repairs (DBTR) has been largely determined by retrospective and small prospective studies.1-4 We hypothesized that a large prospective cohort study of DBTRs performed at our institution would demonstrate similar complication rates. All patients undergoing a primary DBTR by a surgeon from our institution were followed prospectively. The repair technique, post-operative protocol, and follow-up intervals were determined by the individual surgeons’ protocols. At each visit, the surgeon evaluated the patient for any complication, which included infection, wound dehiscence, sensory nerve injury, motor nerve injury, heterotopic ossification, re-rupture, and others. Demographic and surgical data was collected. Descriptive statistics were performed. Sixty patients (59 male, 1 female) underwent 60 distal biceps repairs by 25 orthopaedic surgeons over the course of 6 months. The mean age of the patients was 47 years (Range: 28 - 62), and the mean Body Mass Index (BMI) was 32 (Range: 23 to 54). Surgical techniques included one-incision tension-slide (33 cases), two-incision Modified Boyd Anderson (26 cases), and one-incision suture anchor (1 case). The average time to surgery was 2.9 weeks (Median: 2, Range: 0.5 - 10), the average post-operative length of immobilization was 1.5 weeks (Range: 0 - 4), and the average follow-up was 12 weeks (Range: 6 - 27). The overall complication rate was 23%. There were 14 sensory nerve injuries: 8 lateral antebrachial cutaneous nerves, 2 superficial radial nerves, 1 non-specific hand numbness, and 3 non-specific forearm numbness. Thirteen of 14 sensory nerve injuries occurred with single-incision techniques (38% of one-incision cases vs 4% of two-incision cases). While there was not a single infection, 1 patient had wound blisters, and 1 patient developed olecranon bursitis. Finally, 1 patient re-ruptured his biceps tendon, which required revision surgery. •Patients treated with a one-incision technique have a higher rate of complication than those treated with a two-incision technique.•Sensory nerve injury, specifically to the lateral antebrachial cutaneous nerve, is the most common complication.•The prospective incidence of complications is similar to that obtained retrospectively and reported in the literature.

Superficial Radial Nerve Transection Improves Sensory Outcomes in First Dorsal Metacarpal Artery Flaps.

This article reports the operative technique and clinical effect of repairing thumb pulp defects using a modified first dorsal metacarpal artery flap method. In this method, the dorsal branches of the radial and ulnar proper digital nerves of the index finger were preserved but the superficial branches of the radial nerve were transected. Data obtained from 121 patients with thumb pulp defects who were admitted to the authors' hospital from June of 2011 to December of 2014 were retrospectively analyzed. Patients were divided into two groups based on whether the superficial branches of the radial nerve were transected. The dorsal branches of the radial and ulnar proper digital nerves of the index finger and the proper digital nerves in the wound were coapted using the end-to-end style. Static two-point discrimination, Semmes-Weinstein monofilament scores, pain, cold intolerance of the reconstructed finger, allachesthesia, and patient satisfaction were compared between the two groups. The authors observed significant differences in static two-point discrimination, Semmes-Weinstein monofilament flap score, pain of finger pulp, allachesthesia duration, and patient satisfaction (p < 0.05). The transection group presented slightly better discriminatory sensation in the flap and higher patient satisfaction. In addition, the duration of allachesthesia in the transection group was significantly shorter than that in the preservation group. In the repair of thumb pulp defects using a modified first dorsal metacarpal artery flap carrying the dorsal branches of the radial and ulnar proper digital nerves of the index finger, transecting the superficial branches of the radial nerve achieved better clinical outcome compared with preserving them. Therapeutic, III.

MatriDerm Decreases Donor Site Morbidity After Radial Forearm Free Flap Harvest in Transgender Surgery

BackgroundPhalloplasty with the radial forearm free flap is associated with a large donor site defect. AimTo compare two methods of donor site closure for functional and cosmetic long-term results: full-thickness skin grafting vs split-thickness skin grafting with MatriDerm. MethodsThirty-seven transgender patients had a neophallus created from a radial forearm free flap, and all were operated on by the same senior surgeon. Eight patients had their donor site defect closed by total skin grafting and 29 patients, operated on after 2009, received a split-thickness skin graft with MatriDerm closure. All 37 patients were evaluated by questionnaire and by careful clinical examination. Pressure perception was assessed with the Semmes-Weinstein monofilament test. Sensory recovery, skin quality, and cosmetic result also were compared. The contralateral arm was used as the control. OutcomesPressure perception values showed better sensory return in the MatriDerm group. Split-thickness skin grafting with MatriDerm achieved superior results in skin sensibility, superficial radial nerve recovery, and cosmetic aspect. ResultsOur findings support the hypothesis that MatriDerm can be used to preserve sensory function and decrease morbidity of the donor site. Clinical ImplicationsThe use of a dermal substitute decreases the morbidity of the forearm free flap donor site. Strengths and LimitationsThe strength of this study is its retrospective nature conducted of a prospectively maintained database of 37 consecutive radial forearm free flaps with superimposable dimensions and location performed by the same surgeon, thus limiting biases. A limitation is its small sample (particularly for the control group). ConclusionOur experience showed that the combination of a split-thickness skin graft with MatriDerm substantially decreases postoperative complications at the donor site defect on the forearm of transgender patients.Watfa W, di Summa PG, Meuli J, et al. MatriDerm Decreases Donor Site Morbidity After Radial Forearm Free Flap Harvest in Transgender Surgery. J Sex Med 2017;14:1277–1284.

P249 LEPS abnormalities in the evaluation of dyspigmented and hypoesthetic patches in tuberculoid leprosy

Objectives Leprosy a chronic granulomatous infection of skin and nerves caused by Mycobacterium leprae manifests with hypopigmented and hypoesthetic patches. The aim of our study was to evaluate small fibres dysfunction, by means of laser evoked potentials (LEPs), in these hypoesthetic lesions. Methods A 55-year-old woman, natural from Bolivia, was referred for a suspected tuberculoid leprosy(TL). The patient presented a right thickened superficial radial nerve, infiltrated erythematous and hypochromic patches, some ring-shaped, predominantly in the trunk and upper limbs, with well-defined borders and hypoesthetic. Results Electrophysiological studies evidenced reduced sensory nerve action potential amplitude of the right thickened superficial radial nerve compared to the non-thickened contralateral one. LEPs evidenced reduced amplitude or absent responses stimulating skin dyspigmented patches and normal evoked potentials in the surrounding areas. Skin biopsy showed inflammatory granulomatous infiltration of superficial and deep dermis and enlarged nerve funicles with well formed non caseating granulomas, few epithelioid histiocytes and Langhans-type multinucleated giant cells. Acid-fast bacilli were not observed. Discussion In leprosy, small fibres are most vulnerable for infection with lepra bacilli. LEPs constitute a useful tool to explore small fibre neuropathy of hypoesthetic patches in leprous patients and can objectify and quantify this sensory impairment. Conclusions LEPs abnormalities suggest Adelta fibre involvement in the area of an overlying hypoesthetic lesion and preserved Adelta fibre function in the surrounding areas. Significance This is the first report that documents the use of LEPs as a reliable method to objectify small nerve function impairment.

Utility of nerve conduction studies for diagnosis of injury to the medial branch of the superficial radial nerve.

IntroductionThe clinical utility of nerve conduction study (NCS) for the distal medial branch of the superficial radial nerve (SRN) has not yet been clarified. Therefore, we investigated the clinical utility of NCS in patients with suspected SRN injury and compared the results with those in healthy control subjects.MethodsBilateral NCS of the medial branch of the SRN was performed in two patients with suspected injury of the medial branch of the SRN, and in 20 healthy control subjects. A surface recording electrode was placed at the medial side of the metacarpophalangeal joint of the thumb. The SRN was then stimulated at a location 12 cm proximal from the recording electrode.ResultsThe mean sensory nerve action potential in the two patients was significantly lower than that of the controls (6.75 ± 0.92 vs. 23.8 ± 8.2 μV, P < 0.05). The side-to-side differences in sensory nerve action potential in the two patients were significantly higher than in the controls (55 ± 7.1 vs. 11 ± 7.8%, P < 0.05).ConclusionsNCS may be useful for diagnosing injury of the medial branch of the SRN.

Inhibition of Parkinsonian tremor with cutaneous afferent evoked by transcutaneous electrical nerve stimulation

BackgroundRecent study suggests that tremor signals are transmitted by way of multi-synaptic corticospinal pathway. Neurophysiological studies have also demonstrated that cutaneous afferents exert potent inhibition to descending motor commands by way of spinal interneurons. We hypothesize in this study that cutaneous afferents could also affect the transmission of tremor signals, thus, inhibit tremor in patients with PD.MethodsWe tested this hypothesis by activating cutaneous afferents in the dorsal hand skin innervated by superficial radial nerve using transcutaneous electrical nerve stimulation (TENS). Eight patients with PD having tremor dominant symptom were recruited to participate in this study using a consistent experimental protocol for tremor inhibition. Resting tremor and electromyogram (EMG) of muscles in the upper extremity of these subjects with PD were recorded, while surface stimulation was applied to the dorsal skin of the hand. Fifteen seconds of data were recorded for 5 s prior to, during and post stimulation. Power spectrum densities (PSDs) of tremor and EMG signals were computed for each data segment. The peak values of PSDs in three data segments were compared to detect evidence of tremor inhibition.ResultsAt stimulation intensity from 1.5 to 1.75 times of radiating sensation threshold, apparent suppressions of tremor at wrist, forearm and upper arm and in the EMGs were observed immediately at the onset of stimulation. After termination of stimulation, tremor and rhythmic EMG bursts reemerged gradually. Statistical analysis of peak spectral amplitudes showed a significant difference in joint tremors and EMGs during and prior to stimulation in all 8 subjects with PD. The average percentage of suppression was 61.56% in tremor across all joints of all subjects, and 47.97% in EMG of all muscles. The suppression appeared to occur mainly in distal joints and muscles. There was a slight, but inconsistent effect on tremor frequency in the 8 patients with PD tested.ConclusionsOur results provide direct evidence that tremor in the upper extremity of patients with PD can be inhibited to a large extent with evoked cutaneous reflexes via surface stimulation of the dorsal hand skin area innervated by the superficial radial nerve.