Tenosynovial injection for carpal tunnel syndrome

Influence of Injection Volume on Rate of Subsequent Intervention in Carpal Tunnel Syndrome Over 1-Year Follow-Up

PURPOSE

The optimal volume and dose of corticosteroid injections for treatment of carpal tunnel syndrome (CTS) have not yet been established. It is unknown whether the volume of injectate influences the outcome of carpal tunnel injection. The purpose of this study was to assess whether there is an association between the volume of injectate and subsequent intervention in the treatment of CTS.

METHODS

This study evaluated residents of Olmsted County, MN, who were treated with a corticosteroid injection for CTS between 2001 and 2010. Failure of treatment was the primary outcome, defined as a subsequent intervention: either a second injection or carpal tunnel release within 1 year of initial injection. General estimating equations logistic regression was used to assess the association between injectate volume and rate of treatment failure, adjusting for age, sex, effective dose of steroid, type of steroid injected, electrodiagnostic severity, and the presence of comorbidities such as rheumatoid arthritis, diabetes mellitus, peripheral neuropathy, and radiculopathy.

RESULTS

There were 856 affected hands in 651 patients. A total of 56% (n = 484) of treated hands received subsequent treatment within 1 year. Multivariable analysis showed that a larger injectate volume was significantly associated with reduced rate of treatment failure within 1 year. Rheumatoid arthritis and ultrasound-guided procedures were also associated with a reduced rate of treatment failure, whereas severe electrodiagnostic results were associated with an increased rate of failure.

CONCLUSIONS

This study showed that a larger volume of corticosteroid injection is associated with reduced odds of subsequent intervention after a single corticosteroid injection in CTS. Further research is needed to determine the optimal volume for steroid injections in the treatment of CTS.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

The Accuracy of Common Hand Injections With and Without Ultrasound: An Anatomical Study

BACKGROUND

The aim of the study is to determine the accuracy of hand injections with and without the aid of ultrasound (U/S) into the carpal tunnel, thumb carpometacarpal (CMC) joint, first dorsal compartment (DC) and the radiocarpal (RC) joint.

METHODS

Four participants of various level of experience injected the carpal tunnel, thumb CMC, first DC, and RC joint into 40 fresh frozen cadaver specimens with blue dye and radiographic contrast. Participants 1 and 2 were injected without U/S guidance, and participants 3 and 4 were injected with U/S guidance. A successful injection was determined by both fluoroscopy and dissection/direct observation. Additional information was recorded for each injection such as median nerve infiltration and evidence of thumb CMC arthrosis.

RESULTS

The overall accuracy for carpal tunnel, thumb CMC, first DC, and RC injections were 95%, 63%, 90%, and 90%, respectively. Success was compared with and without U/S guidance. Success rates were similar for each injection site, except the thumb CMC joint, where U/S participants had 25% higher accuracy. In the setting of thumb CMC arthrosis, the incidence of success was 38% for participants with no U/S aid and 72% for participants with U/S aid. There was a significant difference between participants who used U/S with the participant with more U/S experience being more successful.

CONCLUSION

Carpal tunnel, first DC, and RC injections had an accuracy of greater than 90%. Thumb CMC injections have a lower accuracy (63%) and one can improve accuracy with U/S. The accuracy of U/S-guided injections is dependent on the user and their experience.

Carpal Tunnel Injections: A Novel Approach Based on Wrist Width

INTRODUCTION

Carpal tunnel steroid injections (CTIs) have the potential risk of damaging underlying critical structures, including the median nerve (MN), radial artery (RA), and ulnar neurovascular bundle (UB). The purpose of this study was to analyze the safety of a volar radial (VR) and volar ulnar (VU) CTI, using standardized anatomical "safe zones."

MATERIALS AND METHODS

This study was performed on 87 cadaveric arms using a percentage of the total wrist width as a guide for placement of a VR (30 and 33% of total wrist width) and VU (60 and 66% of total wrist width) injection.

RESULTS

Our results demonstrate a wide range of anatomic variations in the location of these critical neurovascular structures near the carpal canal, indicating that using superficial landmarks alone for CTIs may result in an increased risk of iatrogenic injury to these critical structures.

DISCUSSION

We propose a technique using a percentage of total wrist width as a guide for CTIs. Both VR (30% of wrist width) and VU (60% of wrist width) CTIs offer relatively safe and reliable CTI locations to the carpal canal.

LEVEL OF EVIDENCE

Not applicable/cadaveric study.

Assessing the variability of injectate distribution following carpal tunnel injection--a cadaveric study

This anatomical study was designed to assess the distribution of a solution (injectate) made up using local anesthetic, steroid and dye into the carpal tunnel using a commonly used injection technique. Dissections were undertaken in 29 embalmed cadaveric wrists. The cadaveric specimens were dissected 24 hours after injection to observe the effect of time on diffusion patterns in both superficial and deep planes. Eighteen of the 29 specimens showed the presence of the injectate in the superficial plane and three preferential patterns of distribution were noted in the deep plane: free in the carpal tunnel, exclusively in the tendon sheath and mixed. This is the first study investigating the delayed diffusion pattern of injectate in the carpal tunnel and illustrates its variability. The findings of variable degree of superficial diffusion and different patterns of intracarpal spread help to offer some explanation regarding the variability of the response following carpal tunnel injection.

MRI-Based Identification of an Appropriate Point of Needle Insertion for Patients with Idiopathic Carpal Tunnel Syndrome to Avoid Median Nerve Injury

To identify a safe entry point for needle insertion in patients with idiopathic carpal tunnel syndrome (CTS), cross-sectional images of the wrist MRI of 45 normal volunteers and 180 consecutive patients with idiopathic CTS were reviewed. Insertion of the needle from the five different entry points into the carpal tunnel was simulated by drawing a 1-pixel line, and the incidence of contact with the median nerve was compared. In the CTS patients, the lowest incidence was 3% when inserted at one-third of the length between the FCR and FCU tendons on the ulnar side at the level of the distal part of the distal radioulnar joint and 4% at the mid point between the palmaris longus tendona and the flexor carpi ulnaris tendon. It was greater in the advanced stage of CTS than the less severe CTS. We recommend those two entry points.

Comparison of needle position proximity to the median nerve in 2 carpal tunnel injection methods: a cadaveric study

PURPOSE

Steroid injections are commonly performed by hand surgeons for relief of symptoms associated with carpal tunnel syndrome. The purpose of this study is to examine the relationship of the needle to the median nerve within the carpal tunnel and to the palmar cutaneous branch, using 2 injection techniques.

METHODS

Simulated carpal tunnel injections were performed on 15 cadaveric arms using 2 methods. The first injection used a widely accepted approach in which the needle is inserted at the wrist crease, just ulnar to the palmaris longus, and directed at a 30 degrees angle to the horizontal. In the second method, the needle is positioned just ulnar to the palpable ulnar border of flexor carpi radialis and angled 30 degrees to the horizontal. Specimens were dissected using an open carpal tunnel release. Calipers measured the distance from each needle to the median nerve within the carpal tunnel and to the palmar cutaneous branch.

RESULTS

Using the first injection method, the needle pierced the median nerve in 4 specimens, and its mean distance from the nerve measured 1.34 mm +/- 1.83 mm. With the second injection method, the median nerve was pierced in 1 specimen, and the needle averaged a distance of 4.79 mm +/- 3.96 mm from the nerve. In the first approach, the needle averaged 9.47 mm +/- 4.11 mm from the palmar cutaneous branch, compared to 1.74 mm +/- 1.59 mm with the second technique.

CONCLUSIONS

Physicians must exercise caution when performing carpal tunnel injections to avoid intraneural injection. The needle was a statistically significant shorter distance to the median nerve with the traditional injection method; however, the alterative method risks injury to the palmar cutaneous branch of the median nerve.

A novel approach of local corticosteroid injection for the treatment of carpal tunnel syndrome

The objective of the study was to compare the favorable response rate, time duration, and pain level of local corticosteroid injection using a novel approach for the treatment of carpal tunnel syndrome vs a classic approach. Patients with symptomatic carpal tunnel syndrome of less than 1-year duration were randomized for local corticosteroid injection using either the classic approach or a novel approach. In our approach (novel), we used a 29 gauge x 1/2-in. needle and a 1-ml insulin syringe containing 12 mg of methylprednisolone mixed with 0.15 ml of lidocaine 2%, and the site of the injection was 2-3 cm distal to the middle of wrist crease. In the classic approach, we used a 25 gauge x 3-cm needle and a 2-ml syringe injecting 35 mg of methylprednisolone mixed with 0.5 ml of lidocaine 2%, 3-4 cm proximal to the wrist crease and just ulnar to the tendon of the flexor carpi radialis muscle. Response rate was evaluated 1, 3, 6, and 12 weeks after the injection, and also the duration of time of the procedure and the level of pain using the visual analogue scale were compared between the two groups. Forty-two patients signed the consent form, and all of them completed the study [21 patients in the classic approach group (group 1) and 21 patients in the novel approach group (group 2)]. The favorable response rates were 100, 81, 71, and 57% in group 1 and 100, 71, 67, and 57% in group 2 after 1, 3, 6, and 12 weeks, respectively. There was no significant difference in the favorable response rate between the two groups (p=0.468, 95% CI=-12-31%, after 3 weeks). The average duration of time of the procedure in group 1 was 26.71+/-32.83 s compared to 8.48+/-1.123 s (p=0.021) in group 2. The average grade of pain expressed by the patients in group 1 was 4.38+/-1.523 compared to 3.62+/-1.071 in group 2 (p=0.065). In conclusion, local corticosteroid injection using the novel approach for the treatment of carpal tunnel syndrome is helpful, and the favorable response rates are comparable to those using the classic approach after 1, 3, 6, and 12 weeks. The novel approach is much less time consuming and is not more painful.

Repetitive strain injury. 2. Diagnostic and treatment tips on six common problems. The Goff Group

Repetitive strain injury is caused by recurrent overuse, resulting in microtrauma to tissues. Local pain and tenderness, weakness, inflammation, and limited function are common findings. Some of the strain injuries seen most often are carpal tunnel syndrome, trigger finger, shoulder impingement syndrome, tennis elbow, thoracic outlet syndrome, and myofascial pain disorders. Often, treatment can be started at the initial visit, after systemic disorders have been ruled out. A vital step is elimination of aggravating factors, such as improper posture, inadequate attention to ergonomic factors at work, and contributory habits (e.g., jaw or hand clenching). Use of simple joint-protection measures can alleviate much of the discomfort. Appropriate self-help strategies used at home may restore flexibility and strength with a minimum of medical intervention, but pain relief must be achieved before patients can be expected to follow through with rehabilitation efforts. Use of ice packs, massage, NSAIDs, or topical pain-relief agents is often helpful. Prompt, temporary pain relief can also be achieved with injection of a local anesthetic-corticosteroid mixture. Persistent disability should prompt consideration of psychosocial factors. In addition, fraudulent claims of disability do occur. Although physicians should make every effort to support legitimate claims of work-related injury, they should also be aware of the possibility that activities outside of work (e.g., sports participation, accidental injuries) may be contributing factors.

Functional gliding spaces of the dorsal side of the human finger

Although the clinical and functional importance of gliding and connective tissue spaces has been repeatedly emphasized (e.g. their role in the spreading of suppurative phlegmonic inflammation) only few literary findings can be presented dealing with the connective tissue spaces in the finger in the metacarpo-phalangeal transition region. Three separate gliding spaces of the finger above the dorsal aponeurosis and their various regional connections can be displayed by means of a plastic injection technique followed by plastination and production of sectional series. These gliding spaces were also examined on fixed and unfixed hands using plastic injection and subsequent dissection. A space was depicted between the proximal interphalangeal joint and the insertion of the dorsal aponeurosis on the distal phalanx of the finger, as well as a further bursa-like space over the proximal interphalangeal joint. A third space was also depicted between the metacarpophalangeal joint and the proximal interphalangeal joint, which displays a variable connection to the gliding canal of the respective extensor tendons. Methodical, functional and clinical aspects will be discussed.