Ultrasound-guided Perineural Injection Research Articles

Ultrasound-guided perineural injection of the saphenous nerve in goat cadavers

Ultrasound-guided perineural injection of the saphenous nerve in goat cadavers

Ultrasonic visualization technique for anatomical and functional analyses of the sciatic nerve in rats.

Ultrasound has been widely used in the diagnosis and minimally invasive treatment of peripheral nerve diseases in the clinic, but there is still a lack of feasibility analysis in rodent models of neurological disease. The purpose of this study was to investigate the changes in the cross-sectional area of the sciatic nerve of different genders and body weights and to explore the effectiveness and reliability of an ultrasound-guided block around the sciatic nerve in living rats. Using ultrasound imaging anatomy of the sciatic nerve of rats, the cross-sectional area of the sciatic nerve in rats of different genders from 6 to 10 weeks old was calculated, and then analyzed its correlation with body weight. Further analyses were conducted through behavioral and cadaveric studies to evaluate the feasibility of ultrasound-guided perineural injection of the sciatic nerve in rats. We first reported that the sciatic nerve cross-sectional area of rats was increased with age (F = 89.169, P < 0.001), males had a higher sciatic nerve cross-sectional area than females (F = 60.770, P < 0.001), and there was a positive correlation with body weight (rMale = 0.8976, P < 0.001; rFemale = 0.7733, P < 0.001). Behavioral observation of rats showed that the lower extremity complete block rate was 80% following the administration of drugs around the sciatic nerve under ultrasound guidance and staining with methylene blue occurred in all sciatic nerves and surrounding muscles and fascia using 20 ultrasound-guided injections. Ultrasound visualization technology can be used as a new auxiliary evaluation and intervention therapy for animal models of peripheral nerve injury, and will provide overwhelming new references for the basic research of neurological diseases.

Ultrasound-Guided Interventions for Carpal Tunnel Syndrome: A Systematic Review and Meta-Analyses.

Carpal tunnel syndrome (CTS) is the most common peripheral entrapment, and recently, ultrasound-guided perineural injection (UPIT) and percutaneous flexor retinaculum release (UPCTR) have been utilized to treat CTS. However, no systematic review or meta-analysis has included both intervention types of ultrasound-guided interventions for CTS. Therefore, we performed this review using four databases (i.e., PubMed, EMBASE, Scopus, and Cochrane) to evaluate the quality of evidence, effectiveness, and safety of the published studies on ultrasound-guided interventions in CTS. Among sixty studies selected for systemic review, 20 randomized treatment comparison or controlled studies were included in six meta-analyses. Steroid UPIT with ultrasound guidance outperformed that with landmark guidance. UPIT with higher-dose steroids outperformed that with lower-dose steroids. UPIT with 5% dextrose in water (D5W) outperformed control injection and hydrodissection with high-volume D5W was superior to that with low-volume D5W. UPIT with platelet-rich plasma outperformed various control treatments. UPCTR outperformed open surgery in terms of symptom improvement but not functional improvement. No serious adverse events were reported in the studies reviewed. The findings suggest that both UPIT and UPCTR may provide clinically important benefits and appear safe. Further treatment comparison studies are required to determine comparative therapeutic efficacy.

Ultrasound-guided Musculoskeletal Interventional Procedures Around the Hip: A Practical Guide.

Several studies have shown that ultrasound guidance may contribute to improved safety, effectiveness and accuracy of musculoskeletal interventional procedures performed around the hip if compared to those performed with a landmark-guided technique. Different approaches and injectates can be used for treating hip musculoskeletal disorders. These procedures may involve injections in the hip joint, periarticular bursae, tendons, and peripheral nerves. Intra-articular hip injections are mostly used as a conservative approach for treating patients affected by hip osteoarthritis. Ultrasound-guided injection of the iliopsoas bursa is performed in patients with bursitis and/or tendinopathy, to treat those with painful prosthesis due to iliopsoas impingement, or when the lidocaine test is indicated to identify the iliopsoas as a source of pain. Ultrasound-guided interventions are routinely used in patients with greater trochanteric pain syndrome having as target the gluteus medius/minimus tendons and/or the trochanteric bursae. Ultrasound-guided fenestration and platelet-rich plasma injection are applied in patients with hamstring tendinopathy with good clinical outcomes. Last but not least, ultrasound-guided perineural injections can be used for peripheral neuropathies or blocks of the sciatic, lateral femoral cutaneous, and pudendal nerves. In this paper, we discuss the evidence and technical tips for musculoskeletal interventional procedures performed around the hip, highlighting the added value of ultrasound as an imaging guidance modality.

The role of ultrasound-guided perineural injection of the tibial nerve with a sub-anesthetic dosage of lidocaine for the diagnosis of tarsal tunnel syndrome.

Tarsal tunnel syndrome (TTS) involves entrapment of the tibial nerve at the medial ankle beneath the flexor retinaculum and its branches, the medial and lateral plantar nerves, as they course through the porta pedis formed by the deep fascia of the abductor hallucis muscle. TTS is likely underdiagnosed, because diagnosis is based on clinical evaluation and history of present illness. The ultrasound-guided lidocaine infiltration test (USLIT) is a simple approach that may aid in the diagnosis of TTS and predict the response to neurolysis of the tibial nerve and its branches. Traditional electrophysiological testing cannot confirm the diagnosis and only adds to other findings. We performed a prospective study of 61 patients (23 men and 38 women) with a mean age of 51 (29-78) years who were diagnosed with idiopathic TTS using the ultrasound guided near-nerve needle sensory technique (USG-NNNS). Patients subsequently underwent USLIT of the tibial nerve to assess the effect on pain reduction and neurophysiological changes. USLIT led to an improvement in symptoms and nerve conduction velocity. The objective improvement in nerve conduction velocity can be used to document the pre-operative functional capacity of the nerve. USLIT may also be used as a possible quantitative indicator of whether the nerve has the potential to improve in neurophysiological terms and ultimately inform prognosis after surgical decompression. USLIT is a simple technique with potential predictive value that can help the clinician to confirm the diagnosis of TTS before surgical decompression.

Block duration is substantially longer with a liposomal suspension of bupivacaine than with 0.5% bupivacaine HCl potentiated with dexmedetomidine following an ultrasound-guided sciatic nerve block in Beagles

To compare the duration of bupivacaine liposome suspension in the dog with that of bupivacaine and dexmedetomidine following a perineural injection. 8 healthy Beagles. The left sciatic nerve of each dog was randomly assigned to an ultrasound-guided perineural injection with either bupivacaine liposome suspension (BLS) or with 0.5% bupivacaine with dexmedetomidine (1 µg/mL) (BUP-DEX). The contralateral nerve was assigned to the alternate agent. The sensory, motor, and proprioceptive functions were evaluated before the injection (baseline) and at 4, 10, 24, 48, 72, and 96 hours. The block in 1 limb in the BLS treatment appeared to have failed (data set excluded). The motor scores of 2 individuals could not be evaluated leaving 5 limbs to evaluate in the BLS treatment and 6 in the BUP-DEX. A total of 6 out of 7 limbs in the BLS achieved a complete sensory block. In 3 out of 5 treatments with BLS, motor block was only partial and in 2 not apparent at all. Proprioceptive block was partial in 5 out of 7 dogs in the BLS treatment. All functions were still completely obliterated at 10 hours in 6 cases in treatment BUP-DEX. All functions were restored in all cases by 96 and 24 hours after administration of BLS and BUP-DEX, respectively. The blockade characteristics of bupivacaine liposome suspension were effective and long lasting. Motor and proprioceptive deficits may be inconsistent over time.

Effect of Perineural Dextrose Injection on Ulnar Neuropathy at the Elbow: A Randomized, Controlled, Double-Blind Study

ObjectiveTo compare perineural dextrose injection efficacy in the treatment of ulnar neuropathy at the elbow with a control group. DesignProspective double-blind randomized control study. SettingTraining and research hospital. ParticipantsThe study was completed with 40 patients with ulnar neuropathy at the elbow. InterventionNormal saline (0.9% sodium chloride) was injected in patients in the control group (n=20; mean age=38.1±10.7 years; median duration of symptoms=4.5 months), and 5% dextrose was injected in patients in the dextrose group (n=20; mean age=43.6±13.5 years; median duration of symptoms=5 months), perineurally under ultrasound guidance twice at 2-week intervals. Ultrasound-guided perineural injection of 1 cc each was administered into the ulnar nerve, 2 cm and 4 cm distal to the medial epicondyle, at the level of the medial epicondyle, and 2 cm and 4 cm proximal to the medial epicondyle. The amount of total fluid injected was 5 cc. Main Outcome Measure(s)At baseline and weeks 2, 4, and 12, the patients were evaluated with the Visual Analog Scale for pain and the Disabilities of the Arm Shoulder and Hand questionnaire for disability. Electrophysiological evaluation was performed with ulnar nerve conduction studies, and the ulnar nerve cross-sectional area was measured on ultrasonography. ResultsThe improvements in pain, disability, ulnar motor nerve velocity, and ulnar nerve cross-sectional area in the dextrose group were superior to those in the control group, especially at weeks 4 and 12 (P<.001, using independent samples t tests). ConclusionPerineural 5% dextrose may be an effective alternative therapy for those with ulnar neuropathy at the elbow for up to the 12th week.

Efficacy of Ultrasound-Guided Particulate Versus Nonparticulate Steroid Injection in Carpal Tunnel Syndrome: An Open-Label Randomized Control Trial.

IntroductionPerineural corticosteroid injection is an extensively used and accepted treatment for carpal tunnel syndrome (CTS). However, to this date, there is no guideline as to which corticosteroid has to be used as the standard treatment for CTS. Triamcinolone acetonide is a commonly used particulate steroid that can cause permanent nerve injury if it is accidentally injected into the nerve. Conversely, dexamethasone sodium phosphate is a nonparticulate steroid that would not cause permanent nerve damage following accidental injection.MethodsMild to moderate cases of CTS, confirmed by nerve conduction studies (NCS), with symptoms greater than three months were recruited. The participants received one session of ultrasound-guided perineural injection by the in-plane axial ulnar-sided approach with 4 mL of either dexamethasone (dexamethasone sodium phosphate 8 mg (2 mL) + 2 mL 0.5% bupivacaine) or triamcinolone (triamcinolone acetonide 40 mg/mL (1 mL) + 2 mL 0.5% bupivacaine + 1 mL normal saline) solution. The parameters assessed were Phalen’s test time (in seconds), visual analog scale (VAS), and Boston carpal tunnel questionnaire (BCTQ) scores at baseline and two and four months, and NCS changes in sensory nerve conduction velocity (SNCV) and distal motor latency (DML) of the median nerve at baseline and four months. Statistical analysis was conducted using the software SPSS version 26.0 (IBM Corporation, Armonk, NY, USA). Independent samples t-test was used for comparison between groups and the paired t-test for improvement within each group. P values < 0.05 were considered statistically significant.ResultsThe mean age was 42.64 ± 10.99 in the dexamethasone and 45.22 ± 10.602 in the triamcinolone group cases (P = 0.324).There were 58 females (84.06%) and 11 males (15.94%). Each of Phalen’s test time, VAS, and BCTQ scores significantly improved within both dexamethasone and triamcinolone groups at the second and fourth months after injection (P < 0.05). The NCS parameters (SNCV and DML) also significantly improved in both groups at the fourth month after the injection (P < 0.05). However, there were no significant differences in the improvement of Phalen’s test time between the two groups (P = 0.745), VAS score (P = 0.319), BCTQ score (P = 0.137), SNCV (P = 0.511), or DML (P = 0.753). Postprocedural pain lasted significantly longer in the triamcinolone group (P < 0.05). No major complications were noted in either of the two groups.ConclusionDexamethasone is as effective as triamcinolone in improving the symptoms of CTS and can be used as a safer and more effective alternative in the treatment of mild to moderate CTS cases.

A randomized trial to determine the minimum effective lidocaine volume for median nerve block using hydrodissection

Ultrasound-guided hydrodissection with 5% dextrose in water (DW5) creates a peri-nervous compartment, separating the nerve from the neighboring anatomical structures. The aim of this randomized study was to determine the minimum volume of lidocaine 2% with epinephrine 1:200,000 required when using this technique to achieve an effective median nerve block at the elbow in 95% of patients (MEAV95). Fifty-two patients scheduled for elective hand surgery received an ultrasound-guided circumferential perineural injection of 4 ml DW5 and an injection of local anesthetic (LA) following a biased coin up-and-down sequential allocation method. A successful block was defined as a light touch completely suppressed on the two distal phalanges of the index finger within a 30-min evaluation period. The MEAV95 of lidocaine 2% with epinephrine was 4 ml [IQR 3.5–4.0]. Successful median nerve block was obtained in 38 cases (82.6%) with median onset time of 20.0 [10.0–21.2] minutes (95% CI 15–20). The analgesia duration was 248 [208–286] minutes (95% CI 222–276). Using an ultrasound-guided hydrodissection technique with DW5, the MEAV95 to block the median nerve at the elbow with 2% lidocaine with epinephrine was 4 ml [IQR 3.5–4.0]. This volume is close to that usually recommended in clinical practice.Trial registration clinicaltrials.gov. NCT02438657, Date of registration: May 8, 2015.

Effect of Ultrasound-Guided Perineural Injection with Dextrose for Direct Traumatic Injury of Median Nerve

Effect of Ultrasound-Guided Perineural Injection with Dextrose for Direct Traumatic Injury of Median Nerve

Ultrasound-guided Perineural Dextrose Injection for Treatment of Superior Cluneal Nerve Entrapment: Serial Case Report

Background: Superior cluneal nerve entrapment is a neuropathic condition caused by the inclusion of the superior cluneal nerve that contributes to one of the causes of lower back pain leading to high morbidity. Several therapeutic modalities are available for superior cluneal nerve entrapment, including medications, physiotherapy, perineural injection, and surgery. Perineural injection with 5% dextrose has become therapeutic alternative in many cases of neuropathy, but its long-term effectiveness is unknown. Case Presentation: This study described four patients with superior cluneal nerve entrapment with severe pain intensity treated with ultrasonography guided perineural 5% dextrose injection, resulting in significant clinical improvement during the 6-month evaluation. Conclusion: Perineural injection can be considered as long-term therapy in patients with superior cluneal nerve entrapment who have failed other conventional therapies.

Ultrasound-Guided Triamcinolone Acetonide Hydrodissection for Carpal Tunnel Syndrome: A Randomized Controlled Trial.

Background: Despite the wide use of corticosteroid hydrodissection for carpal tunnel syndrome (CTS), there is insufficient evidence to confirm its efficacy. This study aimed to compare the effectiveness of corticosteroid hydrodissection vs. corticosteroid perineural injection alone on clinical and electrophysiological parameters in patients with CTS.Method: This prospective randomized controlled trial (RCT) was conducted in a tertiary care center with a follow-up period of 12 weeks. Subjects were randomly assigned to either ultrasound-guided hydrodissection with a mixture of 1 mL of triamcinolone acetonide (10 mg/mL), 1 mL of 2% lidocaine, and 8 mL normal saline or ultrasound-guided perineural injection with 1 mL of triamcinolone acetonide (40 mg/mL) and 1 mL of 2% lidocaine. The primary outcome measure was the symptom severity subscale (SSS) of Boston Carpal Tunnel Questionnaire (BCTQ) scores at baseline and at 6 and 12 weeks' post-treatment. The secondary outcomes included the functional status subscale (FSS) of BCTQ and the distal motor latency and sensory nerve conduction velocity of the median nerve. The effect of interventions on the designated outcome was analyzed using a 3 × 2 repeated measures analysis of variance. The within-subject and among-subject factors were differences in time (before the intervention, and 6 and 12 weeks after injection) and intervention types (with or without hydrodissection), respectively.Results: Sixty-four patients diagnosed with CTS were enrolled. Both groups experienced improvement in the SSS and FSS of BCTQ and median nerve distal motor latency and sensory nerve conduction velocity. However, group-by-time interactions were not significant in any outcome measurements. No serious adverse events were reported in either group, except for two patients in the hydrodissection group who reported minor post-injection pain on the first day after the intervention, which resolved spontaneously without the need for additional treatments.Conclusion: Hydrodissection did not provide an additional benefit compared to corticosteroid perineural injection alone. More prospective studies are needed to investigate the long-term effectiveness of corticosteroid hydrodissection, as well as its influence on median nerve mobility.

EquineReview

Introduction: This month's Equine Review explores papers on bilateral laparoscopic ovariectomy in mares, the effect of omeprazole on phenylbutazone-induced equine gastric ulcer syndrome and ultrasound-guided perineural injection of cervical nerve in horses.

A study of ultrasound-guided perineural injection of the caudal cervical spinal nerve roots in equine cadavers

ObjectivesTo develop an ultrasound-guided cervical perineural injection technique for horses and to evaluate and compare the distribution of contrast agent among perineural, intra-articular and periarticular injections. Study designProspective, experimental cadaveric study. AnimalsA total of 14 equine cadaveric necks. MethodsBilateral ultrasound-guided perineural injection technique for the caudal cervical spinal nerve roots (CSNRs 5–7) was developed. Paramagnetic or iodinated contrast was injected and the distribution of contrast was evaluated using magnetic resonance (MR) or computed tomography (CT) imaging, respectively. The presence of contrast in the CSNR region was determined by an observer unaware of the technique used for each injection performed. The ability of the perineural injection technique to distribute contrast agent to the CSNR region was compared with intra-articular and periarticular injection techniques. ResultsPerineural injection delivered contrast agent to the CSNR region 100% of the time and was significantly different when compared with intra-articular injection (p = 0.008). There was no difference in ability to deliver contrast agent to the CSNR region between the perineural and periarticular injection techniques or between the intra-articular and periarticular injection techniques. Conclusion and clinical relevanceThe ultrasound-guided perineural injection technique developed in this study accurately delivered contrast agent to the CSNR region in equine cadavers. This technique could potentially be used for the diagnosis and treatment of cervical pain in horses, particularly in cases where intra-articular cervical articular process joint injections have not been beneficial. Further studies are necessary to assess the effectiveness of the ultrasound-guided perineural injection technique in live horses.

Pathogenic Hydrogel? A Novel-Entrapment Neuropathy Model Induced by Ultrasound-Guided Perineural Injections.

Entrapment neuropathy (EN) is a prevalent and debilitative condition caused by a complex pathogenesis that involves a chronic compression–edema–ischemia cascade and perineural adhesion that results in excessive shear stress during motion. Despite decades of research, an easily accessible and surgery-free animal model mimicking the mixed etiology is currently lacking, thus limiting our understanding of the disease and the development of effective therapies. In this proof-of-concept study, we used ultrasound-guided perineural injection of a methoxy poly(ethylene glycol)-b-Poly(lactide-co-glycoilide) carboxylic acid (mPEG-PLGA-BOX) hydrogel near the rat’s sciatic nerve to induce EN, as confirmed sonographically, electrophysiologically, and histologically. The nerve that was injected with hydrogel appeared unevenly contoured and swollen proximally with slowed nerve conduction velocities across the injected segments, thus showing the compressive features of EN. Histology showed perineural cellular infiltration, deposition of irregular collagen fibers, and a possible early demyelination process, thus indicating the existence of adhesions. The novel method provides a surgery-free and cost-effective way to establish a small-animal model of EN that has mixed compression and adhesion features, thus facilitating the additional elucidation of the pathophysiology of EN and the search for promising treatments.

The Efficacy of Hyaluronic Acid for Carpal Tunnel Syndrome: A Randomized Double-Blind Clinical Trial.

To investigate the effect of hyaluronic acid (HA) in patients diagnosed with mild or moderate carpal tunnel syndrome (CTS). A prospective randomized, double-blinded control study with 6 months of follow-up. Rehabilitation outpatient clinic of one single medical center. Thirty-five participants with mild or moderate CTS. Participants were enrolled and randomly assigned to HA or control groups. The HA group received one ultrasound-guided perineural injection of 2.5 mL HA while the control group received 2.5 mL normal saline injection through in-plane, long-axis approach to separate the median nerve from the flexor retinaculum via nerve hydrodissection. Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) scores were the primary outcome, while secondary outcomes included the numeric rating scale (NRS), electrophysiological domains, and the cross-sectional area of the median nerve. The assessment was conducted prior to injection and during the second week and 1-, 3-, and 6-months post-injection. Thirty-two patients (17 wrists in HA group and 15 wrists in control group) completed the study. Compared with the control group, the HA group did not show significantly superior outcomes, except in BCTQ and NRS at the second week post-injection (all P < .0125). A single ultrasound guided perineural HA injection may have short-term therapeutic efficacy for mild or moderate CTS; however, the 2-weeks superior efficacy was not beneficial for chronic neuropathy. Further studies with larger sample sizes are required to verify its therapeutic efficacy.

Ultrasound-guided perineural vs. peritendinous corticosteroid injections in carpal tunnel syndrome: a randomized controlled trial.

Corticosteroid injections are proven to be effective in the management of carpal tunnel syndrome (CTS); however, the optimal injection site still remains unclear. The aim of this study is to compare the efficacy of perineural vs. peritendinous target sites for corticosteroid injection in CTS. A randomized, single-blind, controlled trial. Outpatients, tertiary care center. Forty-six patients were equally randomized into two intervention groups as group A (18 female and five male patients; mean age: 50.0±15.9 years; mean symptom duration: 5.9±3.3 months) and group B (19 female, four male patients; mean age: 54.3±15.0 years; mean symptom duration: 5.9±4.7 months). Methylprednisolone acetate (40 mg) and 1 mL of 1% trimecaine hydrochloride was injected next to the median nerve (group A) or among flexor tendons away from the nerve (group B) under ultrasound (US) guidance. The visual analogue scale was used as the primary outcome measure, and the symptom severity scale and functional status scale of the Boston Carpal Tunnel Questionnaire were used as the secondary subjective outcome measures. Two-point discrimination, grip strength, cross-sectional area, and distal motor latency were assessed as objective outcome measures. The data were collected at baseline and at 2, 6 and 12 weeks after the injection. Both groups showed improvement in subjective and objective measures at 2 weeks following the injection - also maintained up to 12 weeks during the follow-up (P<0.05). However, no difference was observed between the two groups (P<0.05). No serious adverse effects were observed in either group. Both intervention techniques seem to be effective and safe in the conservative treatment of CTS. Based on this study results, it might be noteworthy that physicians can opt for perineural or peritendinous injections without compromising the treatment efficacy and safety. Herewith, US guidance is, for sure, necessary for performing safe and accurate injections.

One-Year Efficacy of Platelet-Rich Plasma for Moderate-to-Severe Carpal Tunnel Syndrome: A Prospective, Randomized, Double-Blind, Controlled Trial

ObjectiveTo assess the therapeutic effect of platelet-rich plasma (PRP) for moderate-to-severe carpal tunnel syndrome (CTS). DesignA prospective, randomized, double-blinded, controlled trial (1-year follow-up). SettingOutpatient of local medical center settings. ParticipantsPatients (N=26) who were diagnosed with bilateral moderate-to-severe CTS (total 52 wrists) were included. For each patient, one wrist was randomized into either the PRP or control group and the contralateral wrist of the same patient was allocated to another group.Twenty-four patients were included in the final data analysis. InterventionsThe wrists in the PRP group received a single ultrasound-guided dose of PRP injection (3.5mL), and the control group received a single ultrasound-guided injection with normal saline (3.5mL). Main Outcome MeasuresThe Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) scores were used as the primary outcome. Secondary outcomes encompassed the cross-sectional area of the median nerve and electrophysiological study. Assessments were conducted prior to injection and 1, 3, 6, and 12 months postinjection. ResultsCompared to the control group, the PRP group exhibited significant improvements in BCTQ severity scores at all time points, BCTQ functional scores at the sixth month, and cross-sectional area at the 12th month postinjection (P<.0125). ConclusionsA single dose of ultrasound-guided perineural PRP injection can provide therapeutic effect for 1 year postinjection.

USG-guided Hydrodissection for Recurrent Ulnar Neuropathy in a Patient with Anteriorly Transposed Nerve

Imaging of peripheral nerves by ultrasound has come into vogue with availability of higher frequency linear transducers and variable sizes of footprints allowing better spatial resolution. Hydrodissection is a novel technique which was elaborated in the literature, not long ago, in 2008. This case report elaborates hydrodissection done for a patient with recurrent symptoms of ulnar neuropathy 4 years after anterior transposition of the nerve. Ultrasound-guided perineural injections of saline and steroid were given 2 months apart and the patient was followed up for 6 months thereafter. Ultrasound-guided hydrodissection technique has gained significant attention in the recent times but it still lacks large studies or trials to validate its safety, establish guidelines on techniques and solutions, thus necessitating exploration in this field.

Long-term outcome after perineural injection with 5% dextrose for carpal tunnel syndrome: a retrospective follow-up study.

Perineural injection therapy with 5% dextrose water is progressively becoming a mainstream method for treating carpal tunnel syndrome. However, its long-term outcome is still unknown. Hence, the purpose of this retrospective study was to investigate the long-term outcome after perineural injection therapy using 5% dextrose water. A total of 185 patients diagnosed with carpel tunnel syndrome at least 1 year post-therapy were enrolled. All the patients underwent ultrasound-guided perineural injection therapy using 10 ml of 5% dextrose water at the outpatient department. In a structured telephone interview, the patients were asked about the outcome post-therapy compared with pre-injection. A symptom relief ≥50% indicated effective outcome, and a symptom relief <50% was indicative of a poor outcome. In total, 88.6% patients reported an effective outcome, and 11.4% rated the outcome as poor, after a mean of 2.2 injections with a mean of 1-3 years' post-injection follow-up. The outcome was significantly related with severity level, and the patients that reported a poor outcome had a significantly higher incidence of severe grade compared with those who reported an effective outcome (52.4% vs 31.7%, P = 0.03). Patients with mild, moderate and severe grades, respectively, required an average of 1.7 (0.1), 2.4 (0.2) and 2.6 (0.3) injections to reach an effective outcome (P = 0.006) (severe vs mild, P = 0.008; moderate vs mild, P = 0.062). Perineural injection therapy is a novel approach for treatment of carpal tunnel syndrome with safe and outstanding long-term effects.