The effects of hypertonic dextrose injection on connective tissue and nerve conduction through the rabbit carpal tunnel

Comparative Efficacy of 5% Dextrose and Corticosteroid Injections in Carpal Tunnel Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE

This study aims to assess the effectiveness of 5% dextrose (D5W) in comparison to corticosteroids for treating carpal tunnel syndrome (CTS).

DATA SOURCES

A comprehensive systematic search was conducted across MEDLINE (PubMed), Embase, and the Cochrane Central Register of Controlled Trials on November 13, 2023. These were supplemented by manual searches using Google Scholar.

STUDY SELECTION

Two independent authors reviewed the literature, resolving any discrepancies through detailed discussions and consultation with a third author.

DATA EXTRACTION

Data on primary outcomes (pain assessment) and secondary outcomes (symptom severity and functional status using the Boston Carpal Tunnel Questionnaire, electrophysiologic measures, cross-sectional area, and adverse effects) were extracted independently by the 2 authors (M.W. and H.H.).

DATA SYNTHESIS

The analysis included 4 randomized controlled trials and 1 quasi-experimental study, encompassing a total of 212 patients (220 hands) with mild to moderate CTS.

RESULTS

Within 3 months, the D5W injections showed a statistically significant improvement in functional status compared to the corticosteroids with a standard mean difference of -0.34 (95% CI, -0.62 to -0.05). D5W was associated with fewer adverse incidents than corticosteroids (risk ratio, 0.13; 95% CI: 0.03-0.51). No difference was observed between the 2 treatments in other areas.

CONCLUSIONS

For patients with mild to moderate CTS, D5W injections were more effective than corticosteroid injections in improving functional status and demonstrated fewer adverse effects. D5W injections also paralleled corticosteroids in pain reduction, symptom severity, electrodiagnostic measures, and cross-sectional area of nerve, recommending D5W as a preferred treatment for mild to moderate CTS.

Ultrasound-Guided Perineural Dextrose Injection for Superior Cluneal Nerve Neuropathy Treatment

INTRODUCTION

Superior cluneal nerve (SCS) entrapment neuropathy is an often overlooked cause of low back pain. Nerve block is usually applied to the sensitive point on the iliac crest where Tinel positivity is detected, with a mixture of a corticosteroid and a local anesthetic. Dextrose injection is one of the treatment methods. There are not enough studies comparing the effectiveness of dextrose and steroid injections. In this study, it was planned to compare these two methods.

MATERIALS AND METHODS

This retrospective study included 16 patients who underwent ultrasound-guided steroid injection and 17 patients who underwent ultrasound-guided dextrose injection with the diagnosis of SCS neuropathy at Elazığ Fethi Sekin City Hospital Polyclinics between 01.09.2023 and 28.03.2024. Patients were evaluated with visual analog scale (VAS) and Roland-Morris Disability Questionnaire (RMDQ) scores before and after the procedure at week 1 Results: While VAS and RMDQ scores were similar in both groups before the procedure, VAS and RMDQ scores at week 1 were significantly lower in the dextrose group.

CONCLUSION

Perineural dextrose injection appears to be a safe and effective alternative to steroid injections in the treatment of SCS neuropathy.

The effect of perineural injection therapy on neuropathic pain: a retrospective study

Background

Among the various pain-related diseases that can be encountered at the clinic, there is a neuropathic pain that is difficult to treat. Numerous methods have been proposed to treat neuropathic pain, such as taking medication, nerve block with lidocaine, or neurolysis with alcohol or phenol. Recently, a method of perineural injection using dextrose instead of lidocaine was proposed. This study was designed to compare the effects of perineural injection therapy (PIT) with buffered 5% dextrose or 0.5% lidocaine on neuropathic pain.

Methods

The data were collected from the database of pain clinic from August 1st, 2019 to December 31st, 2022 without any personal information. The inclusion criteria were patients diagnosed with postherpetic neuralgia (PHN), trigeminal neuralgia (TN), complex regional pain syndrome (CRPS), or peripheral neuropathy (PN), and patients who had undergone PIT with buffered 5% dextrose (Dextrose group) or 0.5% lidocaine (Lidocaine group) for pain control. The data of patients, namely sex, age, and pain score (numerical rating scale, NRS) were collected before PIT. The data of NRS, side effects, and satisfaction grade (excellent, good, fair, or poor) were collected one week after each of the four PIT, and two weeks after the last PIT.

Results

Overall, 112 subjects were enrolled. The Dextrose group included 89 and Lidocaine group included 23 patients. Because the number of patients in the Lidocaine group was too small to allow statistical analysis, the trend in Lidocaine group was just observed in each disease. There were no significant side effects except for a few bruise cases on the site of injection in all groups. The NRS in most Dextrose groups except CRPS were reduced significantly; however, the Lidocaine group showed a trend of pain reduction only in PHN. The Dextrose group except CRPS showed increased satisfaction two weeks after the final PIT.

Conclusion

From the results, it is suggested that PIT with buffered 5% dextrose may have a good effect for neuropathic pain without any side effect except for patients with CRPS. This may offer a window into a new tool that practitioners can employ in their quest to help patients with neuropathic pain.

Impact of High Fat Diet and Sex in a Rabbit Model of Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is a common musculoskeletal disorder, characterized by fibrosis of the subsynovial connective tissue (SSCT) mediated by transforming growth factor beta (TGF-β). Risk factors for CTS include metabolic dysfunction and age. Additionally, the incidence of CTS is higher in women. In this study we hypothesized that a high-fat diet (HFD), a common driver of metabolic dysfunction, would promote SSCT fibrosis found in CTS and that this response would be sex dependent. To test this, we examined the effects of HFD and sex on SSCT fibrosis using our established rabbit model of CTS. Forty-eight (24 male, 24 female) adult rabbits were divided into four groups including HFD or standard diet with and without CTS induction. SSCT was collected for histological and gene expression analysis. HFD promoted SSCT thickening and upregulated profibrotic genes, including TGF-β. Fibrotic genes were differentially expressed in males and females. Interestingly while the prevalence of CTS is greater in women than in men, the converse is observed in the presence of metabolic dysfunction. This work recapitulates this clinical observation and begins to elucidate the sex-based differences found in SSCT fibrosis. This knowledge should drive further research and may lead to metabolic and sex specific therapeutic strategies for the treatment of patients with CTS.

A protocol for a randomized clinical trial assessing the efficacy of hypertonic dextrose injection (prolotherapy) in chronic ankle instability

BACKGROUND

Lateral ankle sprain (LAS) is a common injury. Conservative care is not uniformly effective. Chronic ankle instability (CAI) results in up to 70% of patients with LAS in the physically active population. LAS, together with subsequent osteochondral lesions and pain in many patients, leads to the development of post-traumatic osteoarthritis, resulting in a substantial direct and indirect personal and societal health burden. Dextrose prolotherapy (DPT) is an injection-based therapy for many chronic musculoskeletal conditions but has not been tested for CAI. This protocol describes a randomized controlled trial to test the efficacy of DPT versus normal saline (NS) injections for chronic ankle instability (CAI).

METHODS AND ANALYSIS

A single-center, parallel-group, randomized controlled trial will be conducted at a university-based primary care clinic in Hong Kong. A total of 114 patients with CAI will be randomly allocated (1:1) to DPT and NS groups. The primary outcome will be the Cumberland Ankle Instability Tool scores at 1 year. The secondary outcomes will be the number of re-sprains in 1 year, the Star Excursion Balance Test, the 5-level of EuroQol 5-dimension questionnaire, and the Foot and Ankle Ability Measure. All outcomes will be evaluated at baseline and at 16, 26, and 52 weeks using a linear mixed model.

DISCUSSION

We hypothesized the DPT is a safe, easily accessible, and effective treatment for patients with CAI. This RCT study will inform whether DPT could be a primary non-surgical treatment for CAI.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2000040213 . Registered on 25 November 2020.

A comprehensive review of intraarticular knee injection therapy, geniculate injections, and peripheral nerve stimulation for knee pain in clinical practice

The knee is the most common joint in adults associated with morbidity. Many pathologies are associated with knee damage, such as gout or rheumathoid arthritis, but the primary condition is osteoarthritis (OA). Not only can osteoarthritis cause significant pain, but it also can result in signficant disability as well. Treatment for this condition varies, starting off with oral analgesics and physical therapy to surgical total knee replacmenet. In the gamut of this various treatments, a conservative approach has included intra articular steroid injections. With time, researchers and clinicians determined that other components injected to the knee may additionally provide relief of this condition. In this investigation, we describe different types of knee injections such as platelet-rich plasma (PRP), hyaluronic acid, stem cells, and prolotherapy. Additionally, we describe the role of geniculate knee injections, radiofrequency, and periopheral nerve stimulation. These treatments should be considered for patients with knee pain refractory to conservative therapies.

Ultrasound-guided 5% dextrose prolotherapy versus corticosteroid injection in carpal tunnel syndrome: a randomized, controlled clinical trial

Aim: The main assessment of this study is to analyze the efficiency of ultrasound-guided dextrose prolotherapy against corticosteroid injections for the treatment of carpal tunnel syndrome. Materials & methods: A total of 54 patients with carpal tunnel syndrome were included. Patients who were assigned into the prolotherapy group were injected with 5cc 5% dextrose water under ultrasound guidance. Patients in the corticosteroid group received ultrasound-guided 1 ml triamcinolone 40 mg/ml injection. Results: The inter-group analysis revealed that dextrose prolotherapy has a similar efficacy as corticosteroid for improving pain intensity, functional limitation in daily life, electrophysiologic parameters and ultrasonographic outcomes. No remarkable difference was found between the two treatments until 3 months of follow-up. Conclusion: Dextrose 5% has similar efficacy as triamcinolone for improving pain intensity, functional limitation in daily life, electrophysiologic parameters and ultrasonographic outcomes.

Combined thoracic medial branch radiofrequency and chemical neurotomy

Objective

Explore the effectiveness of thoracic medial branch neurotomy (MBN) using combined radiofrequency neurotomy and neurolytic lesioning.

Design

A retrospective cohort of consecutive patients with chronic thoracic axial pain treated in a community setting.

Interventions

We included all patients who underwent MBN between 2010 and 2016, selected for MBN primarily based on 70% relief following single or dual diagnostic medial branch blocks. Using 18-gauge cannulas, we placed electrodes and made lesions at the suspected location of the thoracic medial branch based on anatomic knowledge at the time; the thermal lesions were supplemented with 50% dextrose to enhance the lesion radius.

Measures

We defined success as ≥50% relief of their index thoracic pain not returning to baseline for at least six months. Patients not reached for follow-up were considered failures for worst-case analysis.

Results

Twenty-eight patients underwent an initial MBN between 2010 and 2016: Twenty-five of twenty-eight (89%) patients reported ≥70% pain reduction not returning to baseline for six months or longer. Using a worst-case analysis (WCA), patients reported average pain relief of 73% CI (63%,84%) with a mean duration of relief following the initial MBN of 9.9 months CI (6, 13.5). Seventeen of the initial 28 patients had a total of 31 repeat MBNs, 13/17 (76%) having pain relief reinstated after one or more repeat MBNs with an average duration of relief following a first repeat MBNs of 10.9 months CI (6.6,15.2).

Conclusion

Thoracic MBN combined with a mild neurolytic is a potentially effective treatment for thoracic pain in patients selected with positive diagnostic MBB. There were no complications noted. One can reinstate pain relief with repeated MBN in most patients should their symptoms return.

Effects of Hypertonic Dextrose Injection (Prolotherapy) in Lateral Elbow Tendinosis: A Systematic Review and Meta-analysis

OBJECTIVE

To systematic review the effectiveness of hypertonic dextrose prolotherapy (DPT) on pain intensity and physical functioning in patients with lateral elbow tendinosis (LET) compared with other active non-surgical treatments.

DATA SOURCES

Systematic search of CENTRAL, MEDLINE, EMBASE, Web of Science, PubMed, Dimensions, Global Health, NHS Health Technology Assessment, AMED and OVID nursing database from inception to 15 June 2021, without language restrictions.

STUDY SELECTION

Two reviewers independently identified parallel or cross-over RCTs that evaluated the effectiveness of DPT in LET. The search identified 245 records; data from 8 studies (354 patients) were included.

DATA EXTRACTION

Two reviewers independently extracted data and assessed included studies. The Cochrane Risk of Bias 2 tool was used to evaluate risk of bias. The Grading of Recommendation Assessment, Development, and Evaluation approach was used to assess quality of the evidence.

DATA SYNTHESIS

Pooled results favored the use of DPT in reducing tennis elbow pain intensity compared with active controls at 12 weeks post-enrollment, with standardized mean difference (SMD) of -0.44 (95% CI -0.88 to -0.01, P =0.04) and of moderate heterogeneity (I²= 49%). Pooled results also favored the use of DPT on physical functioning compared with active controls at 12 weeks, with DASH score achieving mean difference (MD) -15.04 (95% CI -20.25 to -9.82, P < 0.001) and of low heterogeneity (I²= 0.0%). No major related adverse events have been reported.

CONCLUSIONS

DPT is superior to active controls at 12 weeks for decreasing pain intensity and functioning by margins that meet criteria for clinical relevance in the treatment of LET. While existing studies are too small to assess rare adverse events, for LET patients, especially those refractory to first-line treatments, DPT can be considered a non-surgical treatment option in carefully selected patients. Further high-quality trials with comparison with other injection therapies are needed.

Efficacy of 5% Dextrose Water Injection for Peripheral Entrapment Neuropathy: A Narrative Review

Current non-surgical treatment for peripheral entrapment neuropathy is considered insignificant and unsustainable; thus, it is essential to find an alternative novel treatment. The technique of perineural injection therapy using 5% dextrose water has been progressively used to treat many peripheral entrapment neuropathies and has been proven to have outstanding effects in a few high-quality studies. Currently, the twentieth edition of Harrison’s Principles of Internal Medicine textbook recommends this novel injection therapy as an alternative local treatment for carpal tunnel syndrome (CTS). Hence, this novel approach has become the mainstream method for treating CTS, and other studies have revealed its clinical benefit for other peripheral entrapment neuropathies. In this narrative review, we aimed to provide an insight into this treatment method and summarize the current studies on cases of peripheral entrapment neuropathy treated by this method.

Effect of Hypertonic Dextrose Injection on Pain and Shoulder Disability in Patients with Chronic Supraspinatus Tendinosis: A Randomized Double-Blind Controlled Study

OBJECTIVES

To investigate the effect of hypertonic dextrose injection on pain and disability in patients with chronic supraspinatus tendinosis. The secondary aim was to evaluate its effect on the tendon range of motion (ROM) and morphology.

DESIGN

Randomized double-blind placebo-controlled trial.

SETTING

Outpatient clinic.

PARTICIPANTS

Individuals (N=57) with symptomatic chronic supraspinatus tendinosis.

INTERVENTIONS

Participants were randomly administered ultrasound-guided injections of 20% hypertonic dextrose (study group, n=29) or 5% normal saline (control group, n=28).

MAIN OUTCOME MEASURES

The primary outcome measure was visual analog scale (VAS) scores for pain and Shoulder Pain and Disability Index (SPADI) scores. Secondary outcomes included the ROM and ultrasound examination findings of the supraspinatus tendon at baseline and at 2, 6, and 12 weeks postintervention.

RESULTS

The study group exhibited significant improvements in the VAS (mean difference [MD], -2.1; 95% confidence interval [CI], -2.7 to -1.4; P<.001) and SPADI (MD, -11.6; 95% CI, -16.5 to -6.7; P<.001) scores compared with baseline scores at week 2. However, the effect was not sustained to week 6. Flexion ROM increased at weeks 2 (MD, 14.1; 95% CI, 5.7-22.5; P<.001) and 6 (MD, 8.9; 95% CI, 2.4-15.4; P=.003) compared with baseline. The thickness of the supraspinatus tendon improved at weeks 6 (MD, .50; 95% CI, .26-.74; P<.001) and 12 (MD, .61; 95% CI, .37-.84; P<.001) compared with baseline. The ratio of histograms also improved at weeks 6 (MD, .19; 95% CI, .06-.32; P=.002) and 12 (MD, .26; 95% CI, .10-.41; P<.001) compared with baseline.

CONCLUSION

Hypertonic dextrose injection could provide short-term pain and disability relief in patients with chronic supraspinatus tendinosis. Ultrasound imaging at week 6 revealed changed tendon morphology.

Efficacy of hypertonic dextrose injection (prolotherapy) in temporomandibular joint dysfunction: a systematic review and meta-analysis

Hypertonic dextrose prolotherapy (DPT) has been reported to be effective for temporomandibular disorders (TMDs) in clinical trials but its overall efficacy is uncertain. To conduct a systematic review with meta-analysis of randomized controlled trials (RCTs) to synthesize evidence on the effectiveness of DPT for TMDs. Eleven electronic databases were searched from their inception to October, 2020. The primary outcome of interest was pain intensity. Secondary outcomes included maximum inter-incisal mouth opening (MIO) and disability score. Studies were graded by “Cochrane risk of bias 2” tool; if data could be pooled, a meta-analysis was performed. Ten RCTs (n = 336) with some to high risk of bias were included. In a meta-analysis of 5 RCTs, DPT was significantly superior to placebo injections in reducing TMJ pain at 12 weeks, with moderate effect size and low heterogeneity (Standardized Mean Difference: − 0.76; 95% CI − 1.19 to − 0.32, I² = 0%). No statistically significant differences were detected for changes in MIO and functional scores. In this systematic review and meta-analysis, evidence from low to moderate quality studies show that DPT conferred a large positive effect which met criteria for clinical relevance in the treatment of TMJ pain, compared with placebo injections.

Protocol registration at PROSPERO: CRD42020214305.

Prolotherapy for chronic low back pain: a review of literature

INTRODUCTION

Low back pain is common and imposes major societal burdens for patient suffering and costs. Prolotherapy injections are used for musculoskeletal conditions including tendinopathies, osteoarthritis and low back pain to enhance soft-tissue healing. This review aims to clarify the place of prolotherapy in chronic low back pain (CLBP).

SOURCES OF DATA

Using multiple databases, a systematic search was performed to identify studies detailing the use of prolotherapy to manage CLBP. A total of 12 articles was included in the present work.

AREAS OF AGREEMENT

Considering the level of evidence and the quality of the studies assessed using the modified Coleman Score, prolotherapy is an effective management modality for CLBP patients in whom conservative therapies failed.

AREAS OF CONTROVERSY

The presence of co-interventions and the clinical heterogeneity of the work contributes to confound the overall conclusions.

GROWING POINTS AND AREAS FOR RESEARCH

The analysis of the studies included in the review, using appropriate tools, showed how their quality has decreased over the years, reflecting the need for appropriately powered well planned and performed randomized control trials.

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.

Subsynovial connective tissue development in the rabbit carpal tunnel

The carpal tunnel contains the digital flexor tendons and the median nerve, which are embedded in a unique network of fibrovascular interconnected subsynovial connective tissue (SSCT). Fibrous hypertrophy of the SSCT and subsequent adaptations in mechanical response are found in patients with carpal tunnel syndrome (CTS), but not much is known about the development of the SSCT. This observational study describes the morphological development of SSCT using histology and ultramicroscopy in an animal model at four time points between late-term fetuses through adulthood. A transition is seen between 3 days and 6 weeks post-partum from a dense solid SSCT matrix to a complex multilayered structure connected with collagenous fibrils. These preliminary data show a developmental pattern that matches an adaptive response of the SSCT to loading and motion. Understanding the anatomical development aids in recognizing the pathophysiology of CTS and supports research on new therapeutic approaches.

Median nerve conduction studies in rabbits

BACKGROUND

When planning nerve conduction studies using animal models, the sciatic nerve is often used and the upper extremity nerves are not preferred due to the size of laboratory animals. This study aimed to present the method and mean values of median nerve conduction studies in laboratory rabbits. Fifty-five six-month-old male New Zealand white rabbits weighing 2 to 2.5 kg were included in nerve conduction studies performed under anesthesia. The compound muscle action potential amplitude and distal latency values were recorded for the median motor nerve with the electrodes placed on the flexor digitorum superficialis muscle and tendon.

RESULTS

A total of 110 median nerves were evaluated. The mean amplitude of the median nerve was 30.6 ± 6.8, mV the median nerve distal latency was 1.3 ± 0.2 ms, and the mean intensity of stimulation inducing a response was 2.5 ± 1 mA.

CONCLUSIONS

The mean values obtained by the median motor nerve conduction method in this study can act as a guide for future nerve interventions undertaken in the upper extremities.

The Effects of Dextrose Prolotherapy in Symptomatic Knee Osteoarthritis: A Randomized Controlled Study

Objective: To investigate the effects of dextrose prolotherapy in patients with knee osteoarthritis (KOA). Design: A prospective, randomized-controlled interventional trial. Setting: An outpatient pain medicine clinic. Participants: The study included 66 patients aged 40-70 years with chronic knee pain refractory to conservative therapy and diagnosed as grade II or III KOA according to the Kellgren-Lawrence classification. The patients were assigned to dextrose prolotherapy group (PG; n = 22), saline group (SG; n = 22), or control group (CG; n = 22). Interventions: The intra- and extra-articular dextrose prolotherapy and saline injections were administered to the PG and SG, respectively, at 0, 3, and 6 weeks. The patients were blinded to their injection group status. A home-based exercise program was prescribed for all patients in all three groups. Outcome measures: The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, activity pain, stiffness severity measured using a visual analog scale (VAS), and the health-related quality of life (HRQoL) scores measured using the Short Form-36 (SF-36) subscales were recorded at the baseline, 6-week, and 18-week follow-ups. Results: The WOMAC-pain and VAS-activity pain scores decreased significantly in the PG compared to the SG (p = 0.002 and p < 0.001, respectively) and CG (p < 0.001 and p < 0.001, respectively) at 18 weeks. The WOMAC-stiffness scores decreased in the PG compared to the CG at 18 weeks (p < 0.001). The WOMAC physical functioning scores were improved in the PG compared to the CG at 18 weeks (p < 0.001). The physical component scores of the HRQoL were significantly improved in the PG compared to the CG at 18 weeks (p = 0.016), but the mental component scores of the HRQoL showed no significant differences. Conclusions: These findings suggest that dextrose prolotherapy is effective at reducing pain and improving the functional status and quality of life in patients with KOA.

Prolotherapy injections and physiotherapy used singly and in combination for lateral epicondylalgia: a single-blinded randomised clinical trial

Background

Lateral epicondylalgia (tennis elbow) is a common, debilitating and often treatment-resistant condition. Two treatments thought to address the pathology of lateral epicondylalgia are hypertonic glucose plus lignocaine injections (prolotherapy) and a physiotherapist guided manual therapy/exercise program (physiotherapy). This trial aimed to compare the short- and long-term clinical effectiveness, cost effectiveness, and safety of prolotherapy used singly and in combination with physiotherapy.

Methods

Using a single-blinded randomised clinical trial design, 120 participants with lateral epicondylalgia of at least 6 weeks’ duration were randomly assigned to prolotherapy (4 sessions, monthly intervals), physiotherapy (weekly for 4 sessions) or combined (prolotherapy+physiotherapy). The Patient-Rated Tennis Elbow Evaluation (PRTEE) and participant global impression of change scores were assessed by blinded evaluators at baseline, 6, 12, 26 and 52 weeks. Success rate was defined as the percentage of participants indicating elbow condition was either ‘much improved’ or ‘completely recovered.’ Analysis was by intention-to-treat.

Results

Eighty-eight percent completed the 12-month assessment. At 52 weeks, there were substantial, significant improvements compared with baseline status for all outcomes and groups, but no significant differences between groups. The physiotherapy group exhibited greater reductions in PRTEE at 12 weeks than the prolotherapy group (p = 0.014).

Conclusion

There were no significant differences amongst the Physiotherapy, Prolotherapy and Combined groups in PRTEE and global impression of change measures over the course of the 12-month trial.

Trial registration

ACTRN12612000993897.

Treatment of Temporomandibular Dysfunction With Hypertonic Dextrose Injection (Prolotherapy): A Randomized Controlled Trial With Long-term Partial Crossover

OBJECTIVE

To assess the efficacy and longer-term effectiveness of dextrose prolotherapy injections in participants with temporomandibular dysfunction.

PATIENTS AND METHODS

A randomized controlled trial with masked allocation was conducted from January 14, 2013, through December 19, 2015. Forty-two participants (with 54 joints) meeting temporomandibular dysfunction criteria were randomized (1:1) to 3 monthly intra-articular injections (20% dextrose/0.2% lidocaine or 0.2% lidocaine) followed by as-needed dextrose/0.2% lidocaine injections through 1 year. Primary and secondary outcome measures included a 0 to 10 Numerical Rating Scale score for facial pain and jaw dysfunction; maximal interincisal opening (MIO) measured in millimeters, percentage of joints with 50% or more change (improvement) in pain and function, and satisfaction.

RESULTS

Randomization produced a control group with more female participants (P=.03), longer pain duration (P=.01), and less MIO (P=.01). Upon 3-month analysis, including pertinent covariates, dextrose group participants reported decreased jaw pain (4.3±2.9 points vs 1.8±2.7 points; P=.02), jaw dysfunction (3.5±2.8 points vs 1.0±2.1 points; P=.008), and improved MIO (1.5±4.1 mm vs -1.8±5.1 mm; P=.006). Control group participants received dextrose injections beginning at 3 months. No between-group differences were noted at 12 months; pooled data suggested that jaw pain, jaw function, and MIO improved by 5.2±2.7 points (68%), 4.1±2.8 points (64%), and 2.1±5.5 mm, respectively. Pain and dysfunction improved by at least 50% in 38 of 54 (70%) and 39 of 54 (72%) jaws, respectively.

CONCLUSION

Intra-articular dextrose injection (prolotherapy) resulted in substantial improvement in jaw pain, function, and MIO compared with masked control injection at 3 months; clinical improvements endured to 12 months. Satisfaction was high.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01706172.

Timing of extracorporeal shock wave therapy in rabbits with carpal tunnel syndrome

The purpose of this study is to evaluate the effect of extracorporeal shock wave therapy (ESWT) according to treatment timing in rabbits with 10% dextrose-induced carpal tunnel syndrome (CTS); 0.1-ml 10% dextrose solution was injected under ultrasound guidance twice weekly to the left forepaw subsynovial connective tissue (SSCT) within the carpal tunnel of 36 New Zealand white rabbits to induce CTS. The rabbits were randomly allocated into four groups: G1-S (sham ESWT), G2-E4 (ESWT at 4 weeks), G3-E8 (at 8 weeks), and G4-E16 (at 16 weeks). Radial ESWT (500 pulses, 0.08 mJ/mm² , 2 Hz) was repeated thrice weekly. Median nerve distal motor latency (DML) was measured before injection and at 4, 8, 12, 16, and 20 weeks after the first injection. All rabbits were sacrificed 20 weeks after injection. The median nerve cross-sectional area (CSA) and SSCT thickness were measured with light microscopy. The mean median nerve DML at 4 weeks after the first dextrose injection did not differ from that at preinjection in all groups. The mean median nerve DML significantly increased before ESWT in all groups (p < .05); however, it did not increase in G2-E4 and G3-E8 for 12 weeks after ESWT and in G4-E16 for 4 weeks (p > .05). Mean CSA of the median nerve and mean SSCT thickness in G2-E4 were significantly lower than those in the other groups (p < .05). ESWT may prevent the progression of CTS for 12 weeks in rabbits with dextrose-induced CTS regardless of treatment timing, and early application results in superior outcomes.

The efficacy of dextrose prolotherapy over placebo for temporomandibular joint hypermobility: A systematic review and meta-analysis

OBJECTIVE

The aim of the systematic review was to analyse the available evidence in order to assess the efficacy of dextrose prolotherapy in improving outcomes in temporomandibular joint (TMJ) hypermobility patients as compared to placebo.

METHODS

An electronic search of PubMed, Scopus, CENTRAL and Google scholar databases was performed for English language papers published up to February 2018. Randomised clinical trials (RCTs) and controlled clinical trials (CCTs) comparing dextrose prolotherapy with placebo for TMJ hypermobility were included.

RESULTS

Three RCTs were included in the review. Frequency of subluxation/dislocation was reported by two trials which found no difference between dextrose and placebo. A statistical significant difference in reduction of MMO with the use of dextrose prolotherapy was seen on pooling of data (random: MD = -3.32, 95% CI -5.26 to -1.28; P = 0.0008; I²  = 0%). A statistical significant difference in pain reduction was also seen with dextrose as compared to placebo (random: MD = -1, 95% CI -1.58 to -0.42; P = 0.0007; I²  = 0%).

CONCLUSION

Within the limitations of the study, dextrose prolotherapy may cause significant reduction in mouth opening and pain associated with TMJ hypermobility. Conclusions with regard to reduction of episodes of subluxation/dislocation cannot be drawn. There is a need of more high-quality RCTs with larger sample size and homogenous prolotherapy protocol to draw stronger conclusions on the effect of dextrose prolotherapy in patients with TMJ hypermobility.

Prolotherapy for Osteoarthritis and Tendinopathy: a Descriptive Review

PURPOSE OF REVIEW

Osteoarthritis and overuse tendinopathy are common chronic conditions of high societal and patient burden. The precise etiology of pain and disability in both conditions is multifactorial and not well understood. Patients are often refractory to conservative therapy. The development of new therapeutic options in both conditions is a public health priority. Prolotherapy is an injection-based outpatient regenerative therapy for chronic musculoskeletal conditions, including osteoarthritis and tendinopathy. The authors reviewed the basic science and clinical literature associated with prolotherapy for these conditions.

RECENT FINDINGS

Systematic review, including meta-analysis, and randomized controlled trials suggest that prolotherapy may be associated with symptom improvement in mild to moderate symptomatic knee osteoarthritis and overuse tendinopathy. Although the mechanism of action is not well understood and is likely multifactorial, a growing body of literature suggests that prolotherapy for knee osteoarthritis may be appropriate for the treatment of symptoms associated with knee osteoarthritis in carefully selected patients who are refractory to conservative therapy and deserves further basic and clinical science investigation for the treatment of osteoarthritis and tendinopathy.

Functional outcome from sacroiliac joint prolotherapy in patients with sacroiliac joint instability

OBJECTIVES

Examine the effectiveness of sacroiliac (SI) joint prolotherapy for SI joint instability, and characterize the patients most likely to benefit from this treatment.

DESIGN

Retrospective cohort study.

SETTING

Department of Veterans Affairs outpatient physical medicine clinic.

INTERVENTIONS

Patients referred for low back pain and diagnosed with SI joint instability received a series of three SI joint prolotherapy injections (15% dextrose in lidocaine) at approximately a one-month interval. The outcome of those completing treatment was retrospectively examined, and characteristics were compared between those with at least a minimum clinically important improvement and those without improvement.

MAIN OUTCOME MEASURES

Patients completed the Oswestry Disability Index (ODI) before treatment was initiated, immediately preceding each prolotherapy injection, and at 3-4 month follow-up.

RESULTS

Of 103 treated patients returning for post-treatment follow-up at a median of 117 days, 24 (23%) showed a minimum clinically important improvement despite a median of 2 years with low back pain and a mean (±SD) pre-intervention ODI of 54 ± 15 points. Much of the improvement was evident after the initial prolotherapy injection, and a 15-point improvement in ODI prior to the second prolotherapy injection had a sensitivity of 92% and specificity of 80% for determining which patients would improve.

CONCLUSIONS

A satisfactory proportion of patients with symptomatic SI joint instability as an etiology of low back pain can have clinically meaningful functional gains with prolotherapy treatment. The patients who are not likely to improve with prolotherapy are generally evident by lack of improvement following the initial prolotherapy injection.

The biomechanics of subsynovial connective tissue in health and its role in carpal tunnel syndrome

Carpal Tunnel Syndrome (CTS) is the most common surgically treated problem in the hand. Aside from the neuropathy itself, the most common findings are fibrosis of the subsynovial connective tissue (SSCT) and increased intra carpal tunnel pressure. Normally, the SSCT is a multilayer tissue interspersed among the carpal tendons and nerve. As the tendons move, successive SSCT layers are recruited, forming a gliding unit and providing a limit to differential movement. Exceeding this limit, damages the SSCT as has been shown in both cadavers and animal models. This damage leads to a non-inflammatory response with progressive fibrosis and nerve ischemia leaving the SSCT more susceptible to injury. Although the direct consequences for patients are not fully understood, ultrasound research shows that this fibrosis restricts median nerve displacement during tendon loading. This article aims to provide insights into the mechanical properties of SSCT described so far and place it in the context of CTS pathophysiology. A theoretical damage model concerning the SSCT is proposed showing a chain of events and vicious cycles that could lead to the nerve compression as it is found in CTS. Although not complete, this model could explain the pathophysiological pathway of idiopathic CTS.

Relaxin Modulates the Expression of MMPs and TIMPs in Fibroblasts of Patients with Carpal Tunnel Syndrome

PURPOSE

The aim of this study was to investigate the anti-fibrotic effect of relaxin in subsynovial fibroblasts activated by transforming growth factor beta (TGF-β).

MATERIALS AND METHODS

To test the anti-fibrotic effect of an adenovirus-relaxin construct (Ad-RLN) on subsynovial fibroblasts in vitro, cells from subsynovial connective tissue of patients with carpal tunnel syndrome were activated with TGF-β1 and exposed to Ad-RLN (as a therapeutic gene) or adenovirus-lacZ construct (as a marker gene) for four hours. Subsynovial fibroblast cultures without adenoviral exposure served as controls.

RESULTS

We observed induction of gene expressions of collagen I, III and IV, as well as the abatement of alpha-smooth muscle actin (a-SMA) synthesis, Smad2 phosphorylation, and fibronectin at the protein level, in comparison to controls. In addition, protein expressions of matrix metalloproteinase (MMP) I was significantly induced, whereas the protein expressions of tissue inhibitor of metalloproteinases (TIMP) I and IV were reduced due to relaxin expression.

CONCLUSION

RLN prevents excessive synthesis of extracellular matrix by reducing the expressions of its components, such as fibronectin, a-SMA, and phosphorylated Smad2, by increasing the expression of MMPs; and by decreasing the expression of TIMPs.

Hypertonic dextrose injections (prolotherapy) in the treatment of symptomatic knee osteoarthritis: A systematic review and meta-analysis

Hypertonic dextrose injections (prolotherapy) is an emerging treatment for symptomatic knee osteoarthritis (OA) but its efficacy is uncertain. We conducted a systematic review with meta-analysis to synthesize clinical evidence on the effect of prolotherapy for knee OA. Fifteen electronic databases were searched from their inception to September 2015. The primary outcome of interest was score change on the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Three randomized controlled trials (RCTs) of moderate risk of bias and one quasi-randomized trial were included, with data from a total of 258 patients. In the meta-analysis of two eligible studies, prolotherapy is superior to exercise alone by a standardized mean difference (SMD) of 0.81 (95% CI: 0.18 to 1.45, p = 0.012), 0.78 (95% CI: 0.25 to 1.30, p = 0.001) and 0.62 (95% CI: 0.04 to 1.20, p = 0.035) on the WOMAC composite scale; and WOMAC function and pain subscale scores respectively. Moderate heterogeneity exists in all cases. Overall, prolotherapy conferred a positive and significant beneficial effect in the treatment of knee OA. Adequately powered, longer-term trials with uniform end points are needed to better elucidate the efficacy of prolotherapy.

Chondrogenic Effect of Intra-articular Hypertonic-Dextrose (Prolotherapy) in Severe Knee Osteoarthritis

BACKGROUND

Dextrose injection is reported to improve knee osteoarthritis (KOA)-related clinical outcomes, but its effect on articular cartilage is unknown. A chondrogenic effect of dextrose injection has been proposed.

OBJECTIVE

To assess biological and clinical effects of intra-articular hypertonic dextrose injections (prolotherapy) in painful KOA.

DESIGN

Case series with blinded arthroscopic evaluation before and after treatment.

SETTING

Physical medicine and day surgery practice.

PARTICIPANTS

Symptomatic KOA for at least 6 months, arthroscopy-confirmed medial compartment exposed subchondral bone, and temporary pain relief with intra-articular lidocaine injection.

INTERVENTION

Four to 6 monthly 10-mL intra-articular injections with 12.5% dextrose.

MAIN OUTCOME MEASURES

Visual cartilage growth assessment of 9 standardized medial condyle zones in each of 6 participants by 3 arthroscopy readers masked to pre-/postinjection status (total 54 zones evaluated per reader); biopsy of a cartilage growth area posttreatment, evaluated using hematoxylin and eosin and Safranin-O stains, quantitative polarized light microscopy, and immunohistologic cartilage typing; self-reported knee specific quality of life using the Western Ontario McMaster University Osteoarthritis Index (WOMAC, 0-100 points).

RESULTS

Six participants (1 female and 5 male) with median age of 71 years, WOMAC composite score of 57.5 points, and a 9-year pain duration received a median of 6 dextrose injections and follow-up arthroscopy at 7.75 months (range 4.5-9.5 months). In 19 of 54 zone comparisons, all 3 readers agreed that the posttreatment zone showed cartilage growth compared with the pretreatment zone. Biopsy specimens showed metabolically active cartilage with variable cellular organization, fiber parallelism, and cartilage typing patterns consistent with fibro- and hyaline-like cartilage. Compared with baseline status, the median WOMAC score improved 13 points (P = .013). Self-limited soreness after methylene blue instillation was noted.

CONCLUSIONS

Positive clinical and chondrogenic effects were seen after prolotherapy with hypertonic dextrose injection in participants with symptomatic grade IV KOA, suggesting disease-modifying effects and the need for confirmation in controlled studies. Minimally invasive arthroscopy (single-compartment, single-portal) enabled collection of robust intra-articular data.

LEVEL OF EVIDENCE

IV.

Development of a hyperelastic material model of subsynovial connective tissue using finite element modeling

Carpal tunnel syndrome (CTS) is one of the most common disorders of the hand. Assessment of carpal tunnel tissue mechanical behavior, especially that of the subsynovial connective tissue (SSCT), is important to better understand the mechanisms of CTS. The aim of this study was to develop a hyperelastic material model of human SSCT using mechanical test data and finite element modeling (FEM). Experimental shear test data of SSCT from 7 normal subjects and 7 CTS patients collected in a prior study was used to define material response. Hyperelastic coefficients (μ and α) from the first-order Ogden material property definition were iteratively solved using specimen-specific FEM models simulating the mechanical test conditions. A typical Ogden hyperelastic response for the normal and CTS SSCT was characterized by doing the same with data from all samples averaged together. The mean Ogden coefficients (μ/α) for the normal cadaver and CTS patient SSCT were 1.25×10(-5)MPa/4.51 and 1.99×10(-6)MPa/10.6, respectively when evaluating coefficients for individual specimens. The Ogden coefficients for the typical (averaged data) model for normal cadaver and CTS patient SSCT were 1.63×10(-5)MPa/3.93 and 5.00×10(-7)MPa/9.55, respectively. Assessment of SSCT mechanical response with a hyperelastic material model demonstrated significant differences between patient and normal cadaver. The refined assessment of these differences with this model may be important for future model development and in understanding clinical presentation of CTS.

Anterior cruciate ligament tears treated with percutaneous injection of autologous bone marrow nucleated cells: a case series

Introduction

This was a prospective case series designed to investigate treatment for anterior cruciate ligament (ACL) tears using an injection of autologous bone marrow concentrate.

Methods

Consecutive adult patients presenting to a private outpatient interventional musculoskeletal and pain practice with knee pain, ACL laxity on exam, and magnetic resonance imaging (MRI) evidence of a grade 1, 2, or 3 ACL tears with less than 1 cm retraction were eligible for this study. Eligible patients were treated with an intraligamentous injection of autologous bone marrow concentrate, using fluoroscopic guidance. Pre- and postprocedural sagittal MRI images of the ACLs were analyzed using ImageJ software to objectively quantify changes between pre- and posttreatment scans. Five different types of measurement of ACL pixel intensity were examined as a proxy for ligament integrity. In addition pain visual analog scale (VAS) and Lower Extremity Functional Scale (LEFS) values were recorded at baseline and at 1 month, 3 months, 6 months, and annually postinjection. Objective outcomes measured were pre- to post-MRI measurement changes, as analyzed by the ImageJ software. Subjective outcomes measured were changes in the VAS and LEFS, and a self-rated percentage improvement.

Results

Seven of ten patients showed improvement in at least four of five objective measures of ACL integrity in their postprocedure MRIs. In the entire study group, the mean gray value, median, raw integrated density, and modal gray value all decreased toward low-signal ACLs (P=0.01, P=0.02, P=0.002, and P=0.08), indications of improved ligament integrity. Seven of ten patients responded to the self-rated metrics follow up. The mean VAS change was a decrease of 1.7 (P=0.25), the mean LEFS change was an increase of 23.3 (P=0.03), and mean reported improvement was 86.7%.

Conclusion

Based on this small case series, autologous bone marrow concentrate shows promise in the treatment of grade 1, 2, and possibly grade 3 ACL tears without retraction. Further investigation using a controlled study design is warranted.

Collagen gel contraction as a measure of fibroblast function in an animal model of subsynovial connective tissue fibrosis

Carpal tunnel syndrome (CTS) is a peripheral neuropathy characterized by non-inflammatory fibrosis of the subsynovial connective tissues (SSCT). A rabbit model of CTS was developed to test the hypothesis that SSCT fibrosis causes the neuropathy. We used a cell-seeded collagen-gel contraction model to characterize the fibrosis in this model in terms of cellular mechanics, specifically to compare the ability of SSCT cells from the rabbit model and normal rabbits to contract the gel, and to assess the effect of transforming growth factor-β1,which is upregulated in CTS, on these cells. SSCT fibrosis was induced in six retired breeder female rabbits which were sacrificed at 6 weeks (N = 3) and 12 weeks (n = 3). An additional two rabbits served as controls. SSCT was harvested according to a standard protocol. Gels seeded with SSCT cells from rabbits sacrificed at 6 weeks had significantly higher tensile strength (p < 0.001) and Young's modulus (p < 0.001) than gels seeded with cells from rabbits sacrificed at 12 weeks or control animals. TGF-β1 significantly increased the decay time constant (p < 0.001), tensile strength (p < 0.001), and Young's modulus (p < 0.001) regardless of the cell source. This model may be useful in screening therapeutic agents that may block SSCT fibrosis, identifying possible candidates for CTS treatment.

Carpal tunnel syndrome pathophysiology: role of subsynovial connective tissue

Carpal tunnel syndrome (CTS) is a very common pathology. Its most common diagnosis is idiopathic. Although it is accepted that chronic increase in pressure within the carpal tunnel is responsible for median nerve neuropathy, the exact pathophysiology leading to this pressure increase remains unknown. All the histological studies of the carpal tunnel in the CTS find a noninflammatory thickening of the subsynovial connective tissue (SSCT), which seems to be a characteristic of this pathology. Numerous animal models have been developed to recreate CTS in vivo to develop and improve preventive strategies and effective conservative treatments by a better understanding of its pathophysiology. The creation of a shear injury of the SSCT in a rabbit model induced similar modifications to what is observed in CTS, suggesting that this could be a pathway leading to idiopathic CTS.

Effects of multiple injections of hypertonic dextrose in the rabbit carpal tunnel: a potential model of carpal tunnel syndrome development

BACKGROUND

This study investigated the effects of a series of four hypertonic dextrose injections on the subsynovial connective tissue (SSCT) and median nerve within the carpal tunnel of a rabbit model.

METHODS

Twenty New Zealand white rabbits were used. One forepaw carpal tunnel was randomly injected with 0.1 ml of 10 % dextrose solution. The contralateral forepaw was injected with a similar amount of saline. This injection was made once per week for 4 weeks. The animals were killed at 16 weeks after the initial injection and were evaluated by electrophysiology (EP), SSCT mechanical testing, and histology.

RESULTS

Mechanical testing revealed significantly greater ultimate load and energy absorption in the dextrose injection group compared to the saline injection group (P < 0.05). Histological evaluation revealed SSCT fibrosis and thickening and edema in the median nerve bundles in the dextrose injection group. There was a prolongation in the latency of the EP test in the dextrose injection group (P = 0.08).

CONCLUSIONS

Previous studies had shown that one or two injections of 10 % dextrose could induce moderate SSCT fibrosis and mild EP changes without nerve histology changes. In this study, we have shown that higher doses create more severe fibrosis and, most importantly, more severe neuropathy, suggesting a dose-response effect, and confirming this as a potentially useful animal model for researching the etiology and treatment of carpal tunnel syndrome.

Tendon injury produces changes in SSCT and nerve physiology similar to carpal tunnel syndrome in an in vivo rabbit model

BACKGROUND

The etiology of carpal tunnel syndrome (CTS) remains idiopathic in many cases. Noninflammatory fibrosis of the subsynovial connective tissue (SSCT) within the carpal tunnel is common in CTS, and some clinicians have hypothesized that this fibrosis might be a cause rather than an effect of CTS. An animal model in which to test this hypothesis would be useful. The principal objective of this study was to investigate the effect of a surgical injury on SSCT fibrosis and median nerve function within the carpal tunnel in an in vivo rabbit model.

METHODS

Rabbits were sacrificed 12 weeks after surgery and were evaluated by mechanical testing, histology, transmission and scanning electron microscopy, and electrophysiology.

RESULTS

SSCT fibroblast density (p < 0.0001) and collagen fiber size (p = 0.0004) were significantly higher, and the median nerve distal motor amplitude was significantly lower (p = 0.0018), in the tendon injury group SSCT than in either the sham or control groups.

CONCLUSIONS

Our findings are similar to those seen in patients with carpal tunnel syndrome and suggest that the tendon injury procedure may be the basis of a new animal model of SSCT injury and, possibly, CTS.

The efficacy of dextrose prolotherapy for temporomandibular joint hypermobility: a preliminary prospective, randomized, double-blind, placebo-controlled clinical trial

PURPOSE

The aim of this study was to assess the efficacy of dextrose prolotherapy for the treatment of temporomandibular joint (TMJ) hypermobility.

PATIENTS AND METHODS

A prospective, randomized, double-blind clinical study using a placebo control was carried out. Twelve patients with painful subluxation or dislocation of the TMJ were randomly assigned to 1 of 2 equal-sized groups. Patients in the active group received 4 injections of dextrose solution (2 mL of 10% dextrose and 1 mL of 2% mepivacaine) for each TMJ, each 6 weeks apart, whereas patients in the placebo group received injections of placebo solution (2 mL of saline solution and 1 mL of 2% mepivacaine) on the same schedule. A verbal scale expressing TMJ pain on palpation, maximal mouth opening (MMO), clicking sound, and frequency of luxations (number of locking episodes per month) were assessed at each injection appointment just before the injection procedure and 3 months after the last injection. The collected data were then statistically analyzed.

RESULTS

By the end of the study, each group showed significant improvement in TMJ pain on palpation and number of locking episodes and insignificant improvement in clicking sound. With the exception of the MMO, there were no statistically significant differences throughout the study intervals between the active and placebo groups. The active group showed a significant reduction in MMO at the 12th week postoperatively. Differences compared with mean baseline value remained significant at the end of the follow-up period. On the other hand, the placebo group showed an insignificant difference in MMO throughout the study periods. For the last 2 intervals, the placebo group showed statistically significantly higher mean MMO values than the active group. By the end of the 12th postoperative week, the percentages of decrease in MMO were significantly greater in the active group.

CONCLUSION

Prolotherapy with 10% dextrose appears promising for the treatment of symptomatic TMJ hypermobility, as evidenced by the therapeutic benefits, simplicity, safety, patients' acceptance of the injection technique, and lack of significant side effects. However, continued research into prolotherapy's effectiveness in patient populations with large sample sizes and long-term follow-up is needed.

Effects of hypertonic dextrose injections in the rabbit carpal tunnel

OBJECTIVE

This study investigated the effects of different doses of hypertonic dextrose injection on the carpal tunnel subsynovial connective tissue (SSCT) and median nerve in a rabbit model.

METHODS

Thirty-eight New Zealand white rabbits weighing 4.0-4.5 kg were used. One forepaw carpal tunnel was randomly injected with one of five different treatments: saline-single injection; saline-two injections 1 week apart; 10% dextrose-single injection; 20% dextrose-single injection; or 10% dextrose-two injections 1 week apart. Animals were sacrificed at 12 weeks after the initial injection and were evaluated by electrophysiology (EP), SSCT mechanical testing and histology.

RESULTS

There were significant increases in the energy absorption of the SSCT in the 10% dextrose-double injection group compared to the saline injection groups. SSCT stiffness was also significantly increased in the 10% dextrose-double injection group compared to the other groups. There was a significant increase in the thickness of the SSCT in the 10% dextrose-double injection group compared to the saline-single injection group and a significant decrease in the nerve short-long diameter ratio in the 10% dextrose-double injection group compared to the saline-single injection group. There were no changes in EP among the groups.

CONCLUSIONS

SSCT fibrosis is present for up to 12 weeks after dextrose injection; multiple injections have bigger effects, including what appears to be a secondary change in nerve flattening. This model may be useful to study the effects of external fibrosis on nerve morphology and physiology, such as occurs clinically in carpal tunnel syndrome.