Cutaneous Nerve Research Articles

Medial Femoral Cutaneous Nerve Conduction Study with Distal Stimulation and Recording Technique

Medial Femoral Cutaneous Nerve Conduction Study with Distal Stimulation and Recording Technique

Management of Distal Biceps Tendon Ruptures: A Survey of Fellowship-Trained Subspecialist Elbow Surgeons.

There are several approaches to the management of distal biceps tendon ruptures, with no consensus on what constitutes best practice. An online survey queried the perceptions and management of distal biceps tendon ruptures amongst fellowship-trained subspecialist elbow surgeons, which primarily comprised of members of the Shoulder and Elbow Society of Australia, the national subspecialist interest group of the Australian Orthopaedic Association and the Mayo Clinic Elbow Club (Rochester, MN). One hundred surgeons responded. The median (IQR) experience as orthopedic surgeons amongst respondents was 17 (10-23) years. 78% of respondents saw >10 cases of distal biceps tendon ruptures annually. 95% of respondents would recommend surgery for symptomatic radiologically-confirmed partial tears, the most common indications being pain (83%), weakness (60%), and tear size (48%). 43% of respondents would have grafts available for tears older than 6 weeks. The one-incision approach (70%) was preferred over two-incisions (30%). 78% of one-incision users believed that their repair location was anatomic, compared to 100% of two-incision users. One-incision users were more likely to have encountered lateral antebrachial cutaneous nerve (78% vs 46%) and superficial radial nerve palsies (28% vs 11%). Two-incision users were more likely to have encountered posterior interosseus nerve palsy (21% v 15%), heterotopic ossification (54% vs 42%), and synostosis (14% vs 0%). Re-ruptures were the most common cause of reoperation. The more conservative a respondent's postoperative immobilization was, the less likely they were to have ever encountered re-rupture (14% amongst cast users, 29% amongst splint/brace users, 49% amongst sling users, 100% amongst non-immobilizers). 30% of respondents who placed elbow strength restrictions for 6 months postoperatively encountered re-rupture, compared to 40% amongst those who restricted for 6-12 weeks postoperatively. The operation rate for repair of distal biceps tendon ruptures amongst subspecialist elbow surgeons is high, as seen in our cohort. However, there is a large variation in the approach toward its management. One-incision (anterior) was preferred over two-incisions (posterior). Complications from repair of distal biceps tendon ruptures can be expected even amongst subspecialists, and are associated with surgical approach. The responses imply that more conservative postoperative rehabilitation may be associated with a lower risk of re-rupture.

Meralgia Paresthetica: Relevance, Diagnosis, and Treatment.

Pain and sensory disturbance in the distribution of the lateral femoral cutaneous nerve in the ventrolateral portion of the thigh is called meralgia paresthetica (MP). The incidence of MP has risen along with the increasing prevalence of obesity and diabetes mellitus and was recently estimated at 32 new cases per 100 000 persons per year. In this review, we provide an overview of current standards and developments in the diagnosis and treatment of MP. This review is based on publications retrieved by a selective literature search, with special attention to meta-analyses, systematic reviews, randomized and controlled trials (RCTs), and prospective observational studies. The diagnosis is mainly based on typical symptoms combined with a positive response to an infiltration procedure. In atypical cases, electrophysiological testing, neurosonography, and magnetic resonance imaging can be helpful in establishing the diagnosis. The literature search did not reveal any studies of high quality. Four prospective observational studies with small case numbers and partly inconsistent results are available. In a meta-analysis of 149 cases, pain relief was described after infiltration in 85% of cases and after surgery in 80%, with 1-38 months of follow-up. In another meta-analysis of 670 cases, there was pain relief after infiltration in 22% of cases, after surgical decompression in 63%, and after neurectomy in 85%. Hardly any data are available on more recent treatment options, such as radiofrequency therapy, spinal cord stimulation, or peripheral nerve stimulation. The state of the evidence is limited in both quantity and quality, corresponding to evidence level 2a for surgical and non-surgical methods. Advances in imaging and neurophysiological testing have made the diagnosis easier to establish. When intervention is needed, good success rates have been achieved with surgery (decompression, neurectomy), and variable success rates with infiltration.

Outcomes of Children Diagnosed with Unilateral Retinoblastoma: Retrospective Audit

To evaluate treatment outcomes of children diagnosed with unilateral retinoblastoma. Retrospective study of children diagnosed with unilateral retinoblastoma registered at the Tata Memorial Hospital (TMH), Mumbai from January 2013 to December 2018 and completed the planned curative treatment protocol. For the 98 cases that were analyzed, the median age of presentation was 24 months. The majority of patients had the intraocular disease (n = 72), whereas orbital retinoblastoma was in 26 patients. At the time of presentation, on imaging extra scleral spread was observed in 16 patients whereas 18 patients had optic nerve involvement, 11 patients had both extra scleral invasion and optic nerve involvement. We used the International Classification of Retinoblastoma for grouping. Out of 98 patients, 71 patients were in Group E, 21 were in Group D and 4 were in Group B and 2 were in Group C. For Staging of Retinoblastoma, we used International Retinoblastoma Staging System (IRSS) in our study and 14 patients had Stage 0 disease, 52 patients had Stage I disease, 10 patients had Stage II, 21 patients had Stage III A and 1 patient had Stage III B disease. High-risk features on surgical specimen histopathology were optic nerve cut margin positive in 6 patients, optic nerve involvement in 21 patients, extra scleral spread in 3 patients, Choroidal invasion in 38 and Iris involvement in 10 patients. Primary enucleation was offered in 52 patients whereas 26 patients underwent secondary enucleation. Systemic chemotherapy was received by the patient in the neoadjuvant setting in 17 patients as a form of chemo-reduction and 51 patients received systemic chemotherapy in the adjuvant setting. Intra-arterial chemotherapy was offered to 27 patients as a primary treatment or in conjugation with focal therapy (n = 11). Definitive radiotherapy was offered to only 2 patients and 22 patients received adjuvant radiotherapy. At a median follow-up of 62 months, 2patients had local relapse, which was salvaged by focal therapy in one and enucleation in the other. Ten patients who had leptomeningeal relapse had died. The 5-year local control (LC) is 97.6%, event-free survival (EFS) is 88% and overall survival (OS) is 89.5%. Globe was salvaged in only 16 cases. On univariate analysis, we observed a significant association between overall survival and extraocular and intraocular disease (p-value 0.0), Extra scleral spread (p-value 0.0), optic Nerve involvement (imaging), and an optic nerve cut margin positive (p-value 0.045), ICRB Groups (p-value 0.0) and IRSS stage (p- value 0.024). Retinoblastoma is curable if detected early. Extra ocular disease and high-risk features are associated with inferior outcomes and poor globe salvage rates.

Cadaveric Study of Variations in the Course of Lateral Femoral Cutaneous Nerve: Insight to Prevent Injury.

A recent spurt in incidence of meralgia paresthetica to 0.1-81% due to minimally invasive anterior approach to hip joint has resulted in reinterest in anatomy of lateral femoral cutaneous nerve (LFCN). Familiarity with variations in the course of LFCN will reduce the morbidity associated with orthopedic procedures around the anterior superior iliac spine (ASIS) and inguinal ligament (IL). Twenty five adult human formalin embalmed cadavers were dissected. Course and relations of nerve to ASIS, IL and sartorius muscle was noted, distance of nerve from ASIS at IL was measured and statistically analyzed. Mean distance of LFCN from ASIS at IL was 1.73±1.15 cm. Differences between two sides and sexes was statistically not significant (p=0.51 and p=0.96 respectively). Inferomedial to ASIS, 94% of LFCNs crossed IL with 92% of them present within 4 cm medial to ASIS. Majority of LFCNs (90%) exited pelvis and entered thigh posterior to IL. Out of these nerves 48% were single trunks on entry into thigh, then bifurcated into anterior and posterior branches. Remaining LFCNs bifurcated proximal to IL or at level of IL. Trifurcations were seen in 6% while a rare case of pentafication was observed. In 66% main trunk/branches were present in intermuscular cleft between sartorius muscle and tensor fascia lata. Care should be exercised by surgeons while dissecting around IL as more than half of nerves are liable to be injured during operative procedures. This would help in better anticipation of problem, acceptance and reducing litigation.

Combined Pericapsular Nerve Group Block and Intrapelvic Lateral Femoral Cutaneous Nerve Block Is Associated With Decreased Opioid Consumption After Hip Arthroscopy: A Retrospective Cohort Study.

Ambulatory hip arthroscopies are associated with moderate-to-severe pain often requiring opioid analgesia. Novel motor-sparing blocks, the pericapsular nerve group (PENG) and lateral femoral cutaneous nerve (LFCN) block, have shown efficacy in hip surgery. We sought to investigate the analgesic benefits of these novel blocks in terms of opioid-sparing and discharge efficiency. We conducted a retrospective cohort study with propensity score matching of 224 patients who underwent ambulatory elective unilateral hip arthroscopy. One group received a combined PENG and LFCN block (PENG/LFCN, n = 86), while a second group received only a PENG block (n = 26). A control group (n = 112) received no blocks. The primary outcome was postanesthesia care unit (PACU) mean opioid consumption. Secondary outcomes were maximum numeric rating scale (NRS) pain score, intravenous rescue analgesia, and PACU readiness-for-discharge times. The PENG/LFCN-block group required significantly less opioids than the control group in the PACU (25.98 ± 13.04 vs 14.58 ± 5.77, respectively) and were discharged earlier 2.72 ± 1.16 vs 4.42 ± 1.63 hours, respectively). The combined PENG/LFCN group also used less intravenous rescue opioids than the control group (0.47 ± 1.18 vs 1.44 ± 2.1 mg, respectively) and showed a significant difference in the highest NRS pain scores than the control group (6.01 ± 2.38 vs 6.77 ± 2.1 respectively). The PENG block alone group did not show a significant difference in opioid reduction (21.95 ± 15.83 vs 27.72 ± 15.01, respectively). This retrospective study found that in patients who underwent ambulatory elective unilateral hip arthroscopy, a combined PENG and LFCN block was associated with expedited PACU discharge and a clinically significant reduction in postoperative opioid use. Further study is warranted.

Rapidly progressive multiple system atrophy in a patient carrying LRRK2 G2019S mutation.

Multiple system atrophy (MSA) is considered a primarily sporadic neurodegenerative disease, but the role of genetic is poorly understood. We present a female patient of Moroccan origin who developed a rapidly progressive non-levodopa responsive parkinsonism, gait and balance problems, and dysautonomia including severe bulbar symptoms. She was diagnosed with MSA Parkinsonian-type (MSA-P) and suddenly died at night at 58 years of age. Reduced striatal DAT-SPECT, putaminal hyperintensity on T2-MRI, and hypometabolism with FDG-PET were present. Genetic testing documented a G2019S mutation in the LRRK2 gene. A skin biopsy was obtained and used to perform alpha-synuclein RT-QuIC, which was negative, and immunohistochemical analysis, which demonstrated abnormal alpha-synuclein deposits in cutaneous nerves. Elevated blood neurofilament light chain levels were also documented. LRRK2 mutations are the most common cause of monogenic Parkinson's disease (PD) and G2019S is the most frequent variant. Our patient presented with biological, clinical, and radiological features of MSA, but genetic testing revealed a G2019S LRRK2 mutation, which has been previously reported only in one other case of pathologically proven MSA but with mild progression. In our patient, post-mortem confirmation could not be performed, but RT-QuIC and immunohistochemical findings on skin biopsy support the diagnosis of MSA. G2019S LRRK2 may be linked to an increased risk of MSA. Cases of atypical parkinsonism with rapid disease course should be screened for PD-related genes especially in populations with a high prevalence of mutations in known genes.

New insights at the interface between leprosy and immune-mediated rheumatic diseases.

Leprosy is an infectious and contagious disease of slow evolution, triggered by Mycobacterium leprae. Arthritis is its third most common manifestation, after cutaneous and peripheral nerve involvement. Since musculoskeletal symptoms may be the initial presentation of the disease, it is important for health professionals to recognize its rheumatic manifestations for early diagnosis and appropriate treatment, especially in endemic areas. In addition, cases of leprosy have increased globally, notably in patients undergoing treatment with TNF-α blockers and due to the increase in migration and travel of people from developing countries to developed countries. This review proposes to discuss the main scenarios of mimicry of different rheumatic diseases by leprosy, as well as the role of immunosuppressive drugs used in rheumatology practice in the treatment of reactional states and in the risk of developing the infection.

Lateral Femoral Cutaneous Nerve Transposition With Ultrasound-Guided Wire Localization: 2-Dimensional Operative Video.

Lateral Femoral Cutaneous Nerve Transposition With Ultrasound-Guided Wire Localization: 2-Dimensional Operative Video.

Structural changes in Schwann cells and nerve fibres in type 1 diabetes: relationship with diabetic polyneuropathy

Aims/hypothesisOur aim was to investigate structural changes of cutaneous Schwann cells (SCs), including nociceptive Schwann cells (nSCs) and axons, in individuals with diabetic polyneuropathy. We also aimed to investigate the relationship between these changes and peripheral neuropathic symptoms in type 1 diabetes.MethodsSkin biopsies (3 mm) taken from carefully phenotyped participants with type 1 diabetes without polyneuropathy (T1D, n=25), type 1 diabetes with painless diabetic polyneuropathy (T1DPN, n=30) and type 1 diabetes with painful diabetic polyneuropathy (P-T1DPN, n=27), and from healthy control individuals (n=25) were immunostained with relevant antibodies to visualise SCs and nerve fibres. Stereological methods were used to quantify the expression of cutaneous SCs and nerve fibres.ResultsThere was a difference in the number density of nSCs not abutting to nerve fibres between the groups (p=0.004) but not in the number density of nSCs abutting to nerve fibres, nor in solitary or total subepidermal SC soma number density. The overall dermal SC expression (measured by dermal SC area fraction and subepidermal SC process density) and peripheral nerve fibre expression (measured by intraepidermal nerve fibre density, dermal nerve fibre area fraction and subepidermal nerve fibre density) differed between the groups (all p<0.05): significant differences were seen in participants with T1DPN and P-T1DPN compared with those without diabetic polyneuropathy (healthy control and T1D groups) (all p<0.05). No difference was found between participants in the T1DPN and P-T1DPN group, nor between participants in the T1D and healthy control group (all p>0.05). Correlational analysis showed that cutaneous SC processes and nerve fibres were highly associated, and they were weakly negatively correlated with different neuropathy measures.Conclusions/interpretationCutaneous SC processes and nerves, but not SC soma, are degenerated and interdependent in individuals with diabetic polyneuropathy. However, an increase in structurally damaged nSCs was seen in individuals with diabetic polyneuropathy. Furthermore, dermal SC processes and nerve fibres correlate weakly with clinical measures of neuropathy and may play a partial role in the pathophysiology of diabetic polyneuropathy in type 1 diabetes.Graphical

Using the Neuromuscular Junction Cellular Response to Predict Functional Recovery after Nerve Grafting in a Mouse Experimental Model.

Functional recovery following peripheral nerve injury worsens with increasing time of denervation before repair. Denervated muscle undergoes progressive atrophy that limits the extent to which motor endplates can be reinnervated. The aims of this study were to assess nerve injuries reconstructed at different time points and to identify various neural and muscle-based markers to predict functional outcome, including an in-depth look at the neuromuscular junction (NMJ). Adult wild-type C57BL/6J mice underwent surgery on the sciatic nerve and were divided into 5 groups: (1) nerve cut and repaired, (2) acute (nerve cut and immediately repaired with a 1-cm autograft), (3) subacute (nerve grafted 2 weeks after injury), (4) delayed (nerve grafted 4 weeks after injury), (5) nerve cut and capped. Functional recovery was measured by treadmill and electrodiagnostic tests. Nerves were harvested for histologic evaluation, and leg muscles, for histologic evaluation and NMJ immunofluorescent staining of motor endplate innervation and terminal Schwann cells (tSCs). The delayed graft group performed worst in nearly all parameters. The subacute graft group shared more similarities with the acute group, especially the tSC response (subacute, 48%; acute, 51%) and motor endplate innervation pattern (subacute, 75%; acute, 72%). The only parameters to elucidate differences were muscle weight and motor endplate fragmentation. Traditional axon count failed to capture differences among the 3 groups. The tSC activity and NMJ innervation pattern can be used as predictive markers of functional recovery that capture differences among acute, subacute, and delayed nerve injuries. The tSC activity at the NMJ displayed by immunohistochemical methods can accurately reflect target muscle innervation over time. This can be used as a predictor of reinnervation when timing of nerve reconstruction is delayed, which can be a critically needed tool in clinical scenarios.

Medium term donor-site morbidity after tricortical iliac crest graft harvesting for foot and ankle indications

Purpose of the studyThe retrospective study aimed at assessment of donor site morbidity of tricortical iliac crest graft harvest for foot and ankle indications in a single-surgeon, single-technique group of patients. Materials and methodsConsecutive patients undergoing procedures in foot and ankle requiring grafting from iliac crest were contacted with telephoned questionnaire within a second year post surgery. ResultsAmong the group of 37 patients, 100% follow-up has been achieved. One patient reported continued pain at the donor site, one case of hyperesthesia around the approach and one case of hypoesthesia of lateral cutaneous nerve of the thigh were reported. DiscussionData regarding complications of tricortical bone graft harvest from iliac crest is varied. Long term pain has been reported in up to 29% of cases. Variability of information negatively influences informed consent process. We report the results of homogeneous cohort of patients operated for foot and ankle indications. ConclusionHarvesting of tricortical anterior iliac graft for foot and ankle indications carries minimal risk of long term pain at the donor site.

Anatomical landmarks for ankle block

We aimed to describe anatomical landmarks to accurately locate the five nerves that are infiltrated to accomplish anaesthesia of the foot in an ankle block. Twenty-four formaldehyde-fixed cadaveric ankles were studied. Photographs of cross sections of the frozen legs, cut at a horizontal plane across the most prominent points of the medial and lateral malleoli, were analysed. The curvilinear distance from the most prominent point of the closest malleolus to each of the five cutaneous nerves and their depth from the skin surface were measured. Sural, tibial, deep peroneal, saphenous and medial dorsal cutaneous nerves were located 5.2 ± 1.3, 9.2 ± 2.4, 7.4 ± 1.9, 2.8 ± 1.1, 2.1 ± 0.6 mm deep to the skin surface. The curvilinear distances from the medial malleolus to the tibial, deep peroneal and saphenous nerves were 32.5 ± 8.9, 62.8 ± 11.1 and 24.4 ± 7.9 mm, respectively. The curvilinear distances from the lateral malleolus to the sural and medial dorsal cutaneous branches of superficial peroneal nerves were 27.9 ± 6.3 and 52.7 ± 7.3 mm, respectively. The deep peroneal nerve was found between the tendons of the extensor hallucis longus and the extensor digitorum longus in the majority of specimens, while the medial dorsal cutaneous nerve was almost exclusively found on the extensor digitorum longus tendon. The sural and tibial nerves were located around halfway between the most prominent point of the relevant malleolus and the posterior border of the Achilles tendon. In conclusion, this study describes easily identifiable, palpable bony and soft tissue landmarks that could be used to locate the nerves around the ankle.

Systematic Review of Complications Associated With Proximal Hamstring Tendon Repair.

Although several complications of proximal hamstring tendon ruptures have been reported in the literature, few studies have comprehensively analyzed the complication profile of proximal hamstring tendon repair. To identify the overall rate of complications following proximal hamstring tendon repair and to differentiate these complications into categories. Systematic review; Level of evidence, 4. Included in this review were studies that examined surgical repair of proximal hamstring tendon ruptures; all studies were in English and had an evidence level of 4 or higher. No restrictions were made regarding publication date or methodological quality. Data regarding complications were extracted to calculate the overall complication rate as well as the rate of major and minor complications. A quantitative data synthesis was conducted using the chi-square test to compare the proportion of patients who experienced complications with the endoscopic versus open approach. A total of 43 articles including 2833 proximal hamstring tendon repairs were identified. The overall postoperative complication rate was 15.3% (n = 433). The rate of major complications was 4.6%, including a 1.7% rate of sciatic nerve injury, 0.8% rate of venous thromboembolism, 0.8% reoperation rate, 0.8% rerupture rate, and 0.4% rate of deep infection. Minor complications included a 2.4% rate of posterior femoral cutaneous nerve injury, 2.3% rate of persistent hamstring myopathy, 2.2% rate of persistent sitting pain, 1.8% rate of peri-incisional numbness, 1.1% rate of superficial infection, and 0.8% rate of hematoma/seroma. Proximal hamstring tendon repair is associated with an overall complication rate of 15.3%, including a 4.6% rate of major complications.

A Cadaveric Study of Two Uncommon Cases of Sural Nerve Complex Variation

Abstract Introduction The sural nerve is a sensitive nerve whose function is to provide sensory supply for the posterolateral aspect of the distal third of the leg and the lateral side of the dorsum of the foot. This nerve is formed in the upper third of the calf from the terminal branches of the tibial and common peroneal nerves and the communicating branch of the sural nerve. Objectives The aim of our study is to showcase two anatomical variants of the sural nerve. Materials and methods Two formalin-preserved cadavers, one male and one female, embalmed using formalin 4% were dissected with the intent of being used as teaching materials for the students attending anatomy classes at the “George Emil Palade” University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, Romania. Results In both cases, less common anatomical variations of the formation of sural nerve were discovered. On the male cadaver, we identified the sural nerve as a continuation of the medial sural cutaneous nerve. The lateral sural cutaneous nerve and the communicating branch of the sural nerve were both absent. On the female cadaver, we identified both the medial sural cutaneous nerve and the lateral sural cutaneous nerve. The sural nerve was, however, a continuation of only the lateral sural cutaneous nerve, with the medial sural cutaneous nerve as an independent branch. Conclusions We described two anatomical variants of the sural nerve, which are less common than those documented in the literature.

Primary Regenerative Peripheral Nerve Interfaces Using Devascularized Vastus Lateralis Muscle in Sensate Anterolateral Thigh Flap Donor Sites.

Sensate flaps are increasingly used in diverse areas of plastic surgery. Concurrently, modern techniques in neuroma prevention have emerged, such as regenerative peripheral nerve interface (RPNI). Despite increasing use of sensate flaps, the combined use of donor-site neuroma prevention techniques has yet to be described. We report on the use of primary donor-site RPNI at the time of sensate anterolateral thigh (ALT) reconstructions. In ALT flaps, the vastus lateralis muscle can be segmentally devascularized from perforator dissection. These segments of devascularized vastus lateralis muscle can easily be used and repurposed as the free muscle grafts needed for RPNI, providing a physiologic target for the regenerating neurons. Donor-site neuroma has not been shown to be a significant issue at standard ALT flap donor sites. Sensate ALT flaps involve harvest of the lateral femoral cutaneous nerve and/or additional femoral sensory branches at a more proximal location close to the level of the anterior superior iliac spine, where injury to the lateral femoral cutaneous nerve may be associated with pain. In this series, eight patients underwent senate ALT flaps with the use of primary RPNI at the sensate ALT donor site. At a mean follow-up of 16.3 months (range 5-25 months), there was minimal to no nerve pain and no clinical evidence of donor-site neuroma. As sensate flap reconstructions are increasingly performed in plastic surgery and data on neuroma prevention techniques continue to grow, we propose consideration of their combined use.

General anesthesia with nerve blocks for a patient with femoral fracture and essential thrombocythemia: a case report.

Essential thrombocythemia (ET) is a type of myeloproliferative neoplasm characterized by an abnormal increase in platelets. We report a female patient with a severe femoral fracture and ET who underwent the femoral intramedullary fracture fixation procedure. Her past medical history included hypertension and ET. On the second day of hospitalization, her platelet count was 922 × 109/L. In our case, general anesthesia combined with a femoral nerve block and a lateral femoral cutaneous nerve block were used when the platelet count was within normal range. After surgery, the platelet count increased to 979 × 109/L despite using anticoagulant drugs and hydroxyurea. The postoperative recovery went well after the follow-up of this patient. In this case report, we provide our experience of anesthesia management and review the progress of relevant literature to provide some reference.

Perineural Injection Therapy forChronic Exertional Compartment Syndrome Refractory to Initial Compartment Release: A Case Report.

This is a case of a 26-year-old active duty male with a 1-year history of distal anterolateral leg pain and numbness which would persist following activity cessation. He was referred to physical therapy and eventually orthopedic surgery for bilateral anterior exertional compartment syndrome and underwent bilateral anterolateral fasciotomies. One year after surgery, he continued to have pain along the posterior aspect of his lower legs with residual numbness over his left dorsomedial foot. He was referred to sports medicine for further evaluation and Botox injections without significant symptomatic changes. He subsequently underwent diagnostic ultrasound of his lower legs which showed multiple entrapment points of the left superficial peroneal nerve along the fasciotomy scar. An additional electrodiagnostic study showed left superficial peroneal sensory mononeuropathy. Eighteen months following surgery, he received his first perineural injection therapy (PIT) treatment. A mixture of lidocaine and D5W was prepared to achieve 1 mg/cc which was then injected along his tibial, saphenous, and sural nerves. Following four PIT sessions, the patient's overall lower extremity pain, weakness, and functionality had improved. This case demonstrates potential benefit with PIT in patients with refractory symptoms following surgery for chronic exertional compartment syndrome. These symptoms may be due to chronic irritation of cutaneous nerves and they may benefit from treatment with PIT. Our case may represent a possible paradigm shift in the conservative treatment of chronic exertional compartment syndrome, especially when refractory to surgical compartment release.

Active shrinkage protects neurons following axonal transection

Trauma, vascular events, or neurodegenerative processes can lead to axonal injury and eventual transection (axotomy). Neurons can survive axotomy, yet the underlying mechanisms are not fully understood. Excessive water entry into injured neurons poses a particular risk due to swelling and subsequent death. Using invitro and invivo neurotrauma model systems based on laser transection and surgical nerve cut, we demonstrated that axotomy triggers actomyosin contraction coupled with calpain activity. As a consequence, neurons shrink acutely to force water out through aquaporin channels preventing swelling and bursting. Inhibiting shrinkage increased the probability of neuronal cell death by about 3-fold. These studies reveal a previously unrecognized cytoprotective response mechanism to neurotrauma and offer a fresh perspective on pathophysiological processes in the nervous system.

Contactless photoplethysmography for assessment of small fiber neuropathy.

Chronic pain is a prevalent condition affecting approximately one-fifth of the global population, with significant impacts on quality of life and work productivity. Small fiber neuropathies are a common cause of chronic pain, and current diagnostic methods rely on subjective self-assessment or invasive skin biopsies, highlighting the need for objective noninvasive assessment methods. The study aims to develop a modular prototype of a contactless photoplethysmography system with three spectral bands (420, 540, and 800nm) and evaluate its potential for assessing peripheral neuropathy patients via a skin topical heating test and spectral analyses of cutaneous flowmotions. The foot topical skin heating test was conducted on thirty volunteers, including fifteen healthy subjects and fifteen neuropathic patients. Four cutaneous nerve fiber characterizing parameters were evaluated at different wavelengths, including vasomotor response trend, flare area, flare intensity index, and the spectral power of cutaneous flowmotions. The results show that neuropathic patients had significantly lower vasomotor response (50%), flare area (63%), flare intensity index (19%), and neurogenic component (54%) of cutaneous flowmotions compared to the control group, independent of photoplethysmography spectral band. An absolute value of perfusion was 20%-30% higher in the 420nm band. Imaging photoplethysmography shows potential as a cost-effective alternative for objective and non-invasive assessment of neuropathic patients, but further research is needed to enhance photoplethysmography signal quality and establish diagnostic criteria.