Nerve-Targeted Surgical Treatments for Spasticity: A Narrative Review.

Spasticity is a potentially debilitating symptom of various acquired and congenital neurologic pathologies that, without adequate treatment, may lead to long-term disability, compromise functional independence, and negatively impact mental health. Several conservative as well as non-nerve targeted surgical strategies have been developed for the treatment of spasticity, but these may be associated with significant drawbacks, such as adverse side effects to medication, device dependence on intrathecal baclofen pumps, and inadequate relief with tendon-based procedures. In these circumstances, patients may benefit from nerve-targeted surgical interventions such as (i) selective dorsal rhizotomy, (ii) hyperselective neurectomy, and (iii) nerve transfer. When selecting the appropriate surgical approach, preoperative patient characteristics, as well as the risks and benefits of nerve-targeted surgical intervention, must be carefully evaluated. Here, we review the current evidence on the efficacy of these nerve-targeted surgical approaches for treating spasticity across various congenital and acquired neurologic pathologies.

Adipofascial Perforator Flaps for Peripheral Nerve Resurfacing after External Neurolysis.

Background: External neurolysis is an important approach to treating symptomatic peripheral nerve entrapment. In cases of recurrent neurolysis or particularly extensive neurolysis, a paucity of overlying soft tissue for closure over the freshly liberated nerve presents a challenge to long-term surgical success as primary closure of this tissue may predispose the patient to recalcitrant epineural scarring. We report the intermediate term outcomes of the use of adipofascial perforator flaps as a means of vascularised tissue resurfacing of nerves in these difficult scenarios. Methods: We retrospectively reviewed patients undergoing external neurolysis for painful peripheral nerve lesions who subsequently had soft tissue reconstruction with local adipofascial flaps. Data with regard to age, gender, limb involved, duration of symptoms, number of prior surgeries, operative time, type of flap, vascular basis of flap, duration of follow-up, visual analogue pain score, monofilament sensory testing and complications were collected. Results: We included six patients (four women) with a minimum follow-up period of 17 months (range: 17-25 months). Age ranged from 39 to 60 years of age. Four cases involved the upper extremity and two the lower extremity. Symptoms had been present between 1 and 10 years. All operations utilised a local adipofascial flap perfused by a named perforating vessel emanating from an adjacent axial vessel. Operative time for flap creation and inset was 74 minutes, on average. There was one minor complication owing to superficial wound dehiscence. All patients reported substantial pain relief (≥five-point reduction on visual analogue scale; scores 0-3 at last follow-up) and objective sensory testing demonstrated improvement. Conclusions: Our report pays particular attention to surgical technique that is applicable to both upper and lower extremities in addition to intermediate term safety and pain outcomes. Level of Evidence: Level IV (Therapeutic).

Surgical Technique: Brachioradialis to Extensor Carpi Radialis Longus and Brevis Nerve Transfers for Tetraplegia.

Improving upper extremity function in high cervical spinal cord injury (SCI) patients with tetraplegia is a challenging task owing to the limited expendable donor muscles and nerves that are available. Restoring active wrist extension for these patients is critical because it allows for tenodesis grasp. This is classically achieved with brachioradialis (BR) to extensor carpi radialis brevis (ECRB) tendon transfer, but outcomes are suboptimal because BR excursion is insufficient and its origin proximal to the elbow further limits the functionality of the tendon transfer, particularly in the absence of elbow extension. As an alternative approach to restore wrist extension in patients with ICSHT group 1 SCI, we present the first clinical report of the BR to extensor carpi radialis longus (ECRL) and BR to ECRB nerve transfers.

Small Joint Denervation of the Hand and Thumb Base: History, Anatomy, Technique, and Outcomes.

Painful arthritis of the small joints of the hand is a common condition affecting older adults, with distal interphalangeal joint and thumb carpometacarpal joint being the two most common locations. Younger adults may also develop painful arthritis after trauma and with inflammatory arthropathy. Traditional surgical approaches address the structure of the joints with either arthrodesis or arthroplasty with or without an implant. In recent decades, denervation has been reported as an alternative treatment for painful small joints that are mobile and stable. Publications on denervation often report faster surgery and recovery times than traditional surgeries that manipulate the small joint bony structures. This article reviews the history, anatomy, surgical techniques, and outcomes of denervation of the small joints of the hand.

Symptomatic Neuroma Development following En Bloc Resection of Skeletal and Soft-Tissue Tumors: A Retrospective Analysis of 331 Cases.

BACKGROUND: Although symptomatic neuroma formation has been described in other patient populations, these data have not been studied in patients undergoing resection of musculoskeletal tumors. This study aimed to characterize the incidence and risk factors of symptomatic neuroma formation following en bloc resection in this population. METHODS: The authors retrospectively reviewed adults undergoing en bloc resections for musculoskeletal tumors at a high-volume sarcoma center from 2014 to 2019. The authors included en bloc resections for an oncologic indication and excluded non-en bloc resections, primary amputations, and patients with insufficient follow-up. Data are provided as descriptive statistics, and multivariable regression modeling was performed. RESULTS: The authors included 231 patients undergoing 331 en bloc resections (female, 46%; mean age, 52 years). Nerve transection was documented in 87 resections (26%). There were 81 symptomatic neuromas (25%) meeting criteria of Tinel sign or pain on examination and neuropathy in the distribution of suspected nerve injury. Factors associated with symptomatic neuroma formation included age 18 to 39 [adjusted OR (aOR), 3.6; 95% CI, 1.5 to 8.4; P < 0.01] and 40 to 64 (aOR, 2.2; 95% CI, 1.1 to 4.6; P = 0.04), multiple resections (aOR, 3.2; 95% CI, 1.7 to 5.9; P < 0.001), preoperative neuromodulator requirement (aOR, 2.7; 95% CI, 1.2 to 6.0; P = 0.01), and resection of fascia or muscle (aOR, 0.5; 95% CI, 0.3 to 1.0; P = 0.045). CONCLUSION: The authors' results highlight the importance of adequate preoperative optimization of pain control and intraoperative prophylaxis for neuroma prevention following en bloc resection of tumors, particularly for younger patients with a recurrent tumor burden. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Vascularized Denervated Muscle Targets for Headache Surgery-Presentation and Surgical Management.

Patients with substantial trauma to their occipital nerves and those with recurrent or persistent chronic headaches after occipital nerve decompression surgery require transection of their greater occipital and/or lesser occipital nerves to control debilitating pain. Current techniques, such as burying the transected nerve stump in nearby muscle, do not prevent neuroma formation, and more advanced techniques, such as targeted muscle reinnervation and regenerative peripheral nerve interface, have demonstrated only short-term anecdotal success in the context of headache surgery. Vascularized denervated muscle targets (VDMTs) are a novel technique to address the proximal nerve stump after nerve transection that has shown promise to improve chronic nerve pain and prevent neuroma formation. However, VDMTs have not been described in the context of headache surgery. Here authors describe the etiology, workup, and surgical management of 2 patients with recurrent occipital neuralgia who developed vexing neuromas after previous surgery and were successfully treated with VDMTs, remaining pain-free at 3-year follow-up.

Current Concepts in Lower Extremity Amputation: A Primer for Plastic Surgeons.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the goals of lower extremity reconstruction and identify clinical scenarios favoring amputation. 2. Understand lower extremity amputation physiology and biomechanics. 3. Review soft-tissue considerations to achieve durable coverage. 4. Appreciate the evolving management of transected nerves. 5. Highlight emerging applications of osseointegration and strategies to improve myoelectric prosthetic control. SUMMARY: Plastic surgeons are well versed in lower extremity reconstruction for traumatic, oncologic, and ischemic causes. Limb amputation is an increasingly sophisticated component of the reconstructive algorithm and is indicated when the residual limb is predicted to be more functional than a salvaged limb. Although plastic surgeons have traditionally focused on limb salvage, they play an increasingly vital role in optimizing outcomes from amputation. This warrants a review of core concepts and an update on emerging reconstructive techniques in amputee care.

Google Trends Analysis of Peripheral Nerve Disease and Surgery.

BACKGROUND: Despite advances in the surgical management of peripheral nerve pathologies over the past several decades, it is unknown how public awareness of these procedures has changed. We hypothesize that Google searches for peripheral nerve surgery have increased over time. METHODS: Google Trends was queried for search volumes of a list of 40 keywords related to the following topics in peripheral nerve surgery: spasticity, nerve injury, prosthetics, and nerve pain. Monthly relative search volume over the first 5 years of the study period (2010-2014) was compared with that of the last 5 years (2018-2022) of the study period. RESULTS: Search volumes for keywords "nerve injury," "nerve laceration," "peripheral nerve injury," "nerve repair," "nerve transfer", "neuroma," "neuroma pain," "nerve pain," "nerve pain surgery," and "neuroma pain surgery" all increased more than 10% points in relative search volume over the study period (P < 0.0001 for each keyword). In contrast, searches for "rhizotomy," "spasticity surgery," "targeted muscle reinnervation," "bionic arm," and "myoelectric prosthesis" either decreased or remained stable. Technical terms such as "selective neurectomy," "hyperselective neurectomy," "regenerative peripheral nerve interface," and "regenerative peripheral nerve interface surgery" did not have adequate search volume to be reported by Google Trends. CONCLUSIONS: The increase in Google searches related to nerve injury and pain between 2010 and 2022 may reflect increasing public recognition of these clinical entities and surgical techniques addressing them. Technical terms relating to nerve pain are infrequently searched, surgeons should use plain English terms for online discovery. Interest in spasticity and myoelectric prosthetics remains stable, indicating an opportunity for better public outreach.

The Influence of Psychosocial Factors on Disability and Expected Improvement Before Surgery for Adult Traumatic Brachial Plexus Injury.

PURPOSE: Psychosocial factors influence pain and recovery after extremity trauma and may be targets for early intervention. This may be of particular interest for patients with adult traumatic brachial plexus injury (BPI), given the broad and devastating impact of the injury. We hypothesized that there would be an association between depressive symptoms, anxiety, and pain interference with preoperative disability and expectations for improvement after BPI surgery. METHODS: We enrolled 34 patients into a prospective multicenter cohort study for those undergoing surgery for adult traumatic BPI. Before surgery, participants completed Patient-Reported Outcome Measurement Information System scales for pain interference, anxiety, and depressive symptoms, and a validated BPI-specific measure of disability and expected improvement. We performed Pearson correlation analysis between pain interference, anxiety symptoms, and depressive symptoms with (A) disability and (B) expected improvement. We created separate linear regression models for (A) disability and (B) expected improvement including adjustment for severity of plexus injury, age, sex, and race. RESULTS: Among 34 patients, there was a moderate, statistically significant, correlation between preoperative depressive symptoms and higher disability. This remained significant in a linear regression model adjusted for severity of plexus injury, age, sex, and race. There was no association between severity of plexus injury and disability. Depressive symptoms also were moderately, but significantly, correlated with higher expected improvement. This remained significant in a linear regression model adjusted for severity of plexus injury, age, sex, and race. CONCLUSIONS: Depressive symptoms are associated with greater disability and higher expected improvement before BPI surgery. Screening for depressive symptoms can help BPI teams identify patients who would benefit from early referral to mental health specialists and tailor appropriate expectations counseling for functional recovery. We did not find an association between severity of BPI and patient-reported disability, suggesting either that the scale may lack validity or that the sample is biased. LEVEL OF EVIDENCE: Prognostic II.

Use of Vascularized, Denervated Muscle Targets for Prevention and Treatment of Upper-Extremity Neuromas.

Purpose: Neuroma formation following upper-extremity peripheral nerve injury often results in persistent, debilitating neuropathic pain with a limited response to medical management. Vascularized, denervated muscle targets (VDMTs) offer a newly described surgical approach to address this challenging problem. Like targeted muscle reinnervation and regenerative peripheral nerve targets, VDMTs are used to redirect regenerating axons from an injured nerve into denervated muscle to prevent neuroma formation. By providing a vascularized muscle target that is reinnervated via direct neurotization, VDMTs offer some theoretical advantages in comparison with the other contemporary surgical options. In this study, we followed the short-term pain outcomes of patients who underwent VDMT surgery for neuroma prevention or treatment. Methods: We performed a retrospective chart review of 9 patients (2 pediatric and 7 adult) who underwent VDMTs either for symptomatic upper-extremity neuromas or as a prophylactic measure to prevent primary neuroma formation. In-person and/or telephone interviews were conducted to assess their postoperative clinical outcomes, including the visual analog pain scale simple pain score. Results: Of the 9 patients included in this study, 7 underwent VDMT surgery as a prophylactic measure against neuroma formation, and 2 presented with symptomatic neuromas that were treated with VDMTs. The average follow-up was 5.6 ± 4.1 months (range, 0.5-13.2 months). The average postoperative pain score of the 7 adult patients was 1.1 (range, 0-8). Conclusions: This study demonstrated favorable short-term outcomes in a small cohort of patients treated with VDMTs in the upper extremity. Larger, prospective, and comparative studies with validated patient-reported and objective outcome measures and longer-term follow-ups are needed to further evaluate the benefits of VDMTs in upper-extremity neuroma management and prevention. Type of study/level of evidence: Therapeutic III.

Translational bioengineering strategies for peripheral nerve regeneration: opportunities, challenges, and novel concepts.

Peripheral nerve injuries remain a challenging problem in need of better treatment strategies. Despite best efforts at surgical reconstruction and postoperative rehabilitation, patients are often left with persistent, debilitating motor and sensory deficits. There are currently no therapeutic strategies proven to enhance the regenerative process in humans. A clinical need exists for the development of technologies to promote nerve regeneration and improve functional outcomes. Recent advances in the fields of tissue engineering and nanotechnology have enabled biomaterial scaffolds to modulate the host response to tissue repair through tailored mechanical, chemical, and conductive cues. New bioengineered approaches have enabled targeted, sustained delivery of protein therapeutics with the capacity to unlock the clinical potential of a myriad of neurotrophic growth factors that have demonstrated promise in enhancing regenerative outcomes. As such, further exploration of combinatory strategies leveraging these technological advances may offer a pathway towards clinically translatable solutions to advance the care of patients with peripheral nerve injuries. This review first presents the various emerging bioengineering strategies that can be applied for the management of nerve gap injuries. We cover the rationale and limitations for their use as an alternative to autografts, focusing on the approaches to increase the number of regenerating axons crossing the repair site, and facilitating their growth towards the distal stump. We also discuss the emerging growth factor-based therapeutic strategies designed to improve functional outcomes in a multimodal fashion, by accelerating axonal growth, improving the distal regenerative environment, and preventing end-organs atrophy.

A Systematic Review of Muscle Synergies during a Walking Gait to Define Optimal Donor-Recipient Pairings for Lower Extremity Functional Reconstruction.

Functional lower extremity reconstruction primarily aims to restore independent ambulation. We sought to define the synergies recruited during a walking gait to inform donor selection for various motor deficits. With these findings, we discuss the functional neuromuscular components of independent gait with the goal of informing lower extremity reconstruction. Methods: A systematic review was performed using MEDLINE for articles published between January 2000 and December 2020. Search terms included (1) "motor module(s)," "synergy," "motor pattern," or "motor primitive" and (2) "gait," "walking," "ambulation," or "locomotion." Abstracts/full texts were reviewed by two independent reviewers. Results: A total of 38 studies were selected. The average reported number of synergies and variance accounted for was 4.5 ± 0.9 and 88.6% ± 7.7%, respectively. Four motor modules were conserved across nearly all studies. Conclusions: Walking can be reduced to the sequential activation of four motor modules. Activities during the stance phase are critical for both standing stability and forward progression and should be prioritized for reconstruction with the goal of preserving efficient gait. Muscles recruited during swing, except those used for ankle dorsiflexion, are less prone to injury and benefit from greater redundancy, less often necessitating reconstruction. With the emphasis on stability during stance, several synergistic or sometimes even antagonistic tendons can be used to replace their counterparts and restore efficient, independent ambulation. With a finite supply of donor tissues, and in the absence of well-defined clinical outcomes data, this research allows us to effectively prioritize reconstructive goals and maximize patient outcomes.

Target Receptors of Regenerating Nerves: Neuroma Formation and Current Treatment Options.

Neuromas form as a result of disorganized sensory axonal regeneration following nerve injury. Painful neuromas lead to poor quality of life for patients and place a burden on healthcare systems. Modern surgical interventions for neuromas entail guided regeneration of sensory nerve fibers into muscle tissue leading to muscle innervation and neuroma treatment or prevention. However, it is unclear how innervating denervated muscle targets prevents painful neuroma formation, as little is known about the fate of sensory fibers, and more specifically pain fiber, as they regenerate into muscle. Golgi tendon organs and muscle spindles have been proposed as possible receptor targets for the regenerating sensory fibers; however, these receptors are not typically innervated by pain fibers, as these free nerve endings do not synapse on receptors. The mechanisms by which pain fibers are signaled to cease regeneration therefore remain unknown. In this article, we review the physiology underlying nerve regeneration, the guiding molecular signals, and the target receptor specificity of regenerating sensory axons as it pertains to the development and prevention of painful neuroma formation while highlighting gaps in literature. We discuss management options for painful neuromas and the current supporting evidence for the various interventions.

Radiographic imaging modalities for perinatal brachial plexus palsy: a systematic review.

PURPOSE: Perinatal brachial plexus palsy (PBPP) has a wide spectrum of clinical symptoms that can range from incomplete paresis of the affected extremity to flaccid arm paralysis. Although there is a high rate of spontaneous recovery within the first two years of life, it remains challenging to determine which patients will benefit most from surgical intervention. The diagnostic and predictive use of various imaging modalities has been described in the literature, but there is little consensus on approach or algorithm. The anatomic, pathophysiological, and neurodevelopmental characteristics of the neonatal and infant patient population affected by PBPP necessitate thoughtful consideration prior to selecting an imaging modality. METHODS: A systematic review was conducted using six databases. Two reviewers independently screened articles published through October 2021. RESULTS: Literature search produced 10,329 publications, and 22 articles were included in the final analysis. These studies included 479 patients. Mean age at time of imaging ranged from 2.1 to 12.8 months and investigated imaging modalities included MRI (18 studies), ultrasound (4 studies), CT myelography (4 studies), and X-ray myelography (1 study). Imaging outcomes were compared against surgical findings (16 studies) or clinical examination (6 studies), and 87.5% of patients underwent surgery. CONCLUSION: This systematic review addresses the relative strengths and challenges of common radiologic imaging options. MRI is the most sensitive and specific for identifying preganglionic nerve injuries such as pseudomeningoceles and rootlet avulsion, the latter of which has the poorest prognosis in this patient population and often dictates the need for surgical intervention.

Are We Working Harder for Less Pay? A Survey of Medicare Reimbursement for Hand and Upper Extremity Surgery.

BACKGROUND: Ongoing concern for declining Medicare payment to surgeons may incentivize surgeons to perform more cases to maintain productivity goals. The authors evaluated trends in physician payment, patient charges, and reimbursement ratios for the most common hand and upper extremity surgical procedures. METHODS: The authors examined Medicare surgeon payment, patient charges, and surgical volume from 2012 to 2017 for 83 common surgical procedures, incorporating the year-to-year Consumer Price Index to adjust for inflation. The reimbursement ratio was calculated by dividing payment by charge. Weighted (by surgery type and volume) averages were calculated. RESULTS: Total Medicare surgeon payment increased 5.6 percent to $272 million for the studied procedures. Patient charges were seven times greater than payment, growing 24 percent to $1.9 billion. Despite growth of total payment, the average overall weighted payment for a single surgery decreased 3.5 percent. The average weighted patient charge increased 8 percent, whereas the reimbursement ratio decreased 13 percent. A hand surgeon would need to perform three more cases per 100 in 2017 to maintain the same reimbursement received in 2012. After categorizing these 83 surgical procedures, distal radius fixation (>3 parts, 21 percent increase; >2-part intra-articular, extra-articular, and percutaneous pinning, 17 percent increase), bony trauma proximal to the distal radius (10 percent increase), and upper extremity flap (5 percent increase) were subject to the greatest increases in payment. Payment for forearm fasciotomy (39 percent decrease), endoscopic carpal tunnel release (30 percent decrease), and mass excisions proximal to the wrist (18 percent decrease) decreased the most. CONCLUSIONS: From 2012 to 2017, despite a disproportionate increase in procedure charges, Medicare surgeon payment has not decreased substantially; however, total reimbursement is multifactorial and involves multiple sources of revenue and cost.

Vascularized, Denervated Muscle Targets for Treatment of Symptomatic Neuromas in the Upper Extremity: Description of Operative Technique.

Symptomatic neuromas of the upper extremity often cause persistent, debilitating pain that is resistant to medical management. Following upper extremity amputation, painful neuromas may disrupt rehabilitation efforts and pose a barrier to prosthetic use. Several surgical approaches have been attempted to treat neuromas, each of which suffers from limitations. We have developed a novel technique, the vascularized, denervated muscle target, that offers a compelling new option for primary prevention and secondary treatment of symptomatic neuromas of the upper extremity. Here, we provide a detailed description of our surgical technique as it is applied to neuromas of the upper extremity.

Sustained IGF-1 delivery ameliorates effects of chronic denervation and improves functional recovery after peripheral nerve injury and repair.

Functional recovery following peripheral nerve injury is limited by progressive atrophy of denervated muscle and Schwann cells (SCs) that occurs during the long regenerative period prior to end-organ reinnervation. Insulin-like growth factor 1 (IGF-1) is a potent mitogen with well-described trophic and anti-apoptotic effects on neurons, myocytes, and SCs. Achieving sustained, targeted delivery of small protein therapeutics remains a challenge. We hypothesized that a novel nanoparticle (NP) delivery system can provide controlled release of bioactive IGF-1 targeted to denervated muscle and nerve tissue to achieve improved motor recovery through amelioration of denervation-induced muscle atrophy and SC senescence and enhanced axonal regeneration. Biodegradable NPs with encapsulated IGF-1/dextran sulfate polyelectrolyte complexes were formulated using a flash nanoprecipitation method to preserve IGF-1 bioactivity and maximize encapsulation efficiencies. Under optimized conditions, uniform PEG-b-PCL NPs were generated with an encapsulation efficiency of 88.4%, loading level of 14.2%, and a near-zero-order release of bioactive IGF-1 for more than 20 days in vitro. The effects of locally delivered IGF-1 NPs on denervated muscle and SCs were assessed in a rat median nerve transection-without- repair model. The effects of IGF-1 NPs on axonal regeneration, muscle atrophy, reinnervation, and recovery of motor function were assessed in a model in which chronic denervation is induced prior to nerve repair. IGF-1 NP treatment resulted in significantly greater recovery of forepaw grip strength, decreased denervation-induced muscle atrophy, decreased SC senescence, and improved neuromuscular reinnervation.

Iatrogenic Metastasis of Soft-tissue Sarcoma at the Donor Flap Site: Case Report and Proposed Surgical Oncologic Techniques.

An 81-year-old woman with multiply recurrent undifferentiated pleomorphic sarcoma of the foot underwent wide excision and reconstruction with an anterolateral thigh free flap. Six years postoperatively, she developed biopsy-proven recurrence within the harvest site. No other sites of disease were detected on staging workup. The flap site recurrence was attributed to iatrogenic implantation at the time of harvesting. Iatrogenic metastases are thought to be caused by tumor implantation, which may be attributable to cross-contamination from instrumentation and surgical techniques. In the present article, we highlight preventive techniques and oncologic surgical principles intended to reduce the likelihood of iatrogenic metastasis. Increased awareness by all members of the surgical team may prevent this unfortunate complication.

Utility of Viscoelastic Tests to Predict Flap Thrombosis: A Systematic Review.

BACKGROUND: Flap thrombosis is a rare but devastating complication in microsurgery. Preoperative identification of patients at increased risk for microvascular thrombosis remains challenging. Viscoelastic testing (VET) provides a comprehensive evaluation of the clotting process and can effectively identify hypercoagulability. However, the utility of VET in microvascular reconstruction remains unclear. METHODS: A systematic review of the association between VET and pedicle thrombosis and free flap loss was performed in accordance with Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Identified studies were reviewed independently by two authors for pertinent data. RESULTS: Six studies met inclusion criteria. Heterogenous study design and outcome reporting complicated direct comparisons and precluded a formal meta-analysis. Four studies found a statistically significant relationship between VET results and flap thrombosis or flap loss. The maximum clot strength and the fibrinogen-to-platelet ratio (FPR) were key viscoelastic parameters in these studies, both representing a measure of maximal clot strength. Specifically, an elevated FPR (>42%) generated a sensitivity and specificity for flap loss ranging from 57% to 75% and 60% to 82%, respectively. Notably, the negative predictive value for flap failure with a normal preoperative FPR was greater than 90% in all studies reporting a correlation. The remaining two studies reported no predictive value for VET with respect to flap failure or pedicle thrombosis. CONCLUSION: The results of this review suggest that VET, particularly parameters relating to clot strength, may help clinicians identify patients at risk for flap thrombosis. However, uncontrolled and heterogenous reporting limit definitive conclusions, and high-quality diagnostic studies are needed to better determine the clinical utility of viscoelastic testing for free flap patients.

Insulin-Like Growth Factor-1: A Promising Therapeutic Target for Peripheral Nerve Injury.

Patients who sustain peripheral nerve injuries (PNIs) are often left with debilitating sensory and motor loss. Presently, there is a lack of clinically available therapeutics that can be given as an adjunct to surgical repair to enhance the regenerative process. Insulin-like growth factor-1 (IGF-1) represents a promising therapeutic target to meet this need, given its well-described trophic and anti-apoptotic effects on neurons, Schwann cells (SCs), and myocytes. Here, we review the literature regarding the therapeutic potential of IGF-1 in PNI. We appraised the literature for the various approaches of IGF-1 administration with the aim of identifying which are the most promising in offering a pathway toward clinical application. We also sought to determine the optimal reported dosage ranges for the various delivery approaches that have been investigated.