Prevalence and Subtypes of Tenosynovial Amyloid in Patients Undergoing Carpal Tunnel Release

Amyloidosis Screening by Biopsy During Carpal Tunnel Release: A Systematic Review and Meta-analysis

Background

Cardiac amyloidosis (CA) is an underdiagnosed cause of heart failure with newly available effective therapies. Carpal tunnel syndrome is a common early manifestation of amyloidosis, and tissue obtained during carpal tunnel release (CTR) can be screened for amyloid, allowing for early CA diagnosis and treatment. However, neither screening criteria nor diagnostic yield are well defined. We estimated the prevalence of amyloid within the tenosynovium or transverse carpal ligament and occult CA among patients undergoing screening biopsy during CTR based on the results of published studies.

Methods

We conducted a systematic review and meta-analysis of studies that analyzed screening biopsies obtained at the time of CTR for the presence of amyloid.

Results

Of 21 articles meeting inclusion criteria, 14 included biopsies from a general population undergoing CTR, 5 reported biopsies from a prescreened population at elevated risk for amyloidosis undergoing CTR, and 2 included patients undergoing CTR with suspected amyloidosis. The pooled prevalence of amyloid within the tenosynovium/transverse carpal ligament was 11% (95% confidence interval: 5%-18%) in American and European studies without prescreening, 20% (95% confidence interval: 13%-29%) in studies of screened patients, and 88%-100% in studies of patients suspected of having amyloidosis preoperatively. Overall, 5%-20% of patients with amyloid-positive biopsies who underwent cardiac screening were eventually diagnosed with CA, of whom 33% were started on transthyretin tetramer stabilizers.

Conclusions

Biopsies for amyloid during CTR demonstrate a high rate of positivity among at-risk populations and an opportunity for early detection of occult CA. Future studies should further refine diagnostic criteria to optimize cost-effectiveness of widespread screening.

Differences in the Incidence of Amyloid Deposition in Biopsies Performed During Bilateral Carpal Tunnel Release

PURPOSE

Biopsy during carpal tunnel release (CTR) to assess for amyloid deposition may be indicated in older patients with bilateral symptoms. There is a paucity of prior investigations comparing the results of bilateral CTR biopsy samples. Our purpose was to compare differences in the incidence of amyloid deposition detected during bilateral CTR.

METHODS

We reviewed primary, bilateral (staged or simultaneous) CTR cases from a single-surgeon between March 2022 and September 2024 during which a biopsy was obtained from both sides. The presence of amyloid deposition was determined using Thioflavin T and/or Congo Red staining using established institutional protocols. Baseline demographics were recorded, and the results of bilateral biopsies were compared to assess for disparate results.

RESULTS

A total of 65 patients underwent bilateral CTR where a biopsy was obtained during both procedures. Mean age was 67 years, and 42% were women. Of the 65 included patients, 8 (12%) had evidence of amyloid deposition on at least one biopsy. Six patients overall (9%) had disparate biopsy results, accounting for 75% of positive cases. In these six patients, four (67%) had evidence of amyloid deposition during the first biopsy and no evidence of amyloid on the second biopsy. Two of six patients (33%) had no evidence of amyloid deposition during the first biopsy but did have evidence of amyloid on the second biopsy.

CONCLUSIONS

Biopsy results differ with respect to amyloid deposition in 9% of bilateral CTR cases. Seventy-five percent of patients with evidence of amyloid deposition on at least one extremity will have discordant bilateral biopsy results. In patients where the index biopsy is positive during a CTR, a contralateral biopsy may not be necessary. However, in patients where the index biopsy is negative for amyloid deposition, we recommend repeating the biopsy during the second (contralateral) CTR.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Early Amyloid Diagnosis and Treatment: Experience of Single Hand Surgeon With a Series of 182 Carpal Tunnel Biopsies

BACKGROUND

Amyloidosis is a systemic disease characterized by buildup of abnormal amyloid deposits that may lead to multiple organ failure and is associated with early onset musculoskeletal manifestations. Orthopedic surgeons are positioned to aid with early diagnosis in the form of a biopsy which allows for workup for other areas of disease, specifically cardiac manifestations, and intervention prior to irreversible cardiac damage. In this review, we describe the biopsy results of a series of 182 patients and workup and treatment of the 46 amyloid positive patients biopsied by a single surgeon during a 4-year period.

METHODS

We retrospectively reviewed biopsy results from 2019 to 2024 for all patients who met criteria for biopsy at time of open carpal tunnel release (CTR). All surgeries were performed by a single surgeon at a single academic institution. Patient selection was based on a previously published algorithm.

RESULTS

Forty-six (25.3%) of 182 patients who underwent CTR and met criteria for biopsy were found to test positive on Congo red staining and liquid chromatography tandem mass spectrometry. All 46 patients were referred to cardiology for evaluation. Thirty-three patients completed cardiology evaluation and 32 of those patients were started on treatment as a result of testing.

CONCLUSIONS

The incidence of amyloid positive biopsy results was 25.3% in a single surgeon, single institution study using currently accepted screening criteria. All positive patients were referred for cardiac imaging and evaluation to obtain early diagnosis of amyloid cardiomyopathy and initiate treatment if indicated. A significant portion of patients referred to cardiology (58%) were started on pharmacological management as a result.

LEVEL OF EVIDENCE

Retrospective cohort study, II, prognostic.

Occult Amyloid Deposition in Older Patients Presenting With Bilateral Carpal Tunnel Syndrome or Multiple Trigger Digits

PURPOSE

The diagnosis of amyloidosis is important for early intervention, disease monitoring, and prevention of complications and progression. Carpal tunnel syndrome (CTS) and trigger digit (TD) are two common conditions associated with early disease. The purpose of this study was to define disease prevalence among patients with bilateral CTS and multiple TDs and assess for an increased rate of diagnosis in the presence of both.

METHODS

Men older than 50 years and women older than 60 years of age diagnosed with bilateral CTS, multiple TDs, or a combination of the 2 were prospectively enrolled in our study. Tenosynovial biopsy samples taken at the time of surgery were tested for the presence of amyloid using Congo red staining. Demographic and medical covariates were also collected and analyzed for differences between amyloid-positive and -negative patients.

RESULTS

Fifty-six patients were enrolled in the study, and nine patients tested positive for amyloid deposition. The demographics and medical comorbidities were similar between amyloid-positive and -negative patients. Thirty patients with bilateral CTS were enrolled, and four tested positive for amyloid. For patients with multiple TDs, a total of 17 patients were enrolled, and 4 tested positive for amyloid. Among patients with multiple TDs, only men tested positive for amyloid and were, on average, younger than those who tested negative (61 and 73 years, respectively). Patients presenting with a combination of CTS and TD did not exhibit increased amyloid discovery.

CONCLUSIONS

Hand surgeons should consider tenosynovial biopsy in men older than 50 years and women older than 60 years presenting with either bilateral CTS or multiple TDs.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Amyloidosis and carpal tunnel syndrome: can we predict occurrence?

INTRODUCTION

Carpal tunnel syndrome, especially when bilateral, may be associated with amyloid deposits, a precursor of systemic amyloidosis. Systemic amyloidosis affects various organs, cardiac involvement having the poorest prognosis. Diagnosis is often delayed. Current treatments are only effective in the early stages of the disease. The primary objective of our study was to evaluate the incidence of amyloidosis in patients with bilateral carpal tunnel syndrome; the secondary aim was to screen for cardiac forms.

MATERIAL AND METHODS

Between 2019 and 2023, we conducted a single-center prospective observational and diagnostic study to investigate the anatomical pathology of amyloid deposits in tenosynovial samples taken during open nerve release surgery on the median nerve. The tenosynovial biopsy was sent to a specific laboratory for analysis, and typing if positive. If amyloidosis was detected, the patient was referred to a specialist for a specific work-up.

RESULTS

We included 54 patients, with a mean age of 67 years (range, 51-89 years): 16 men and 38 women. Sixteen analyses were positive, 12 of which were transthyretin and 4 non-typed.

DISCUSSION/CONCLUSION

Bilateral carpal tunnel syndrome was predictive of amyloidosis. As synovial biopsy during surgery is simple and rapid, it should be implemented to identify amyloidosis at an early stage. This could change prognosis, by improving survival through screening and initiation of early specific treatment.

LEVEL OF EVIDENCE

IV.

Exploring the Utility of Carpal Tunnel Biopsy in Amyloidosis: A Current Perspective

Recent literature has emphasized the role of hand surgeons in screening patients with carpal tunnel syndrome (CTS) for amyloidosis by performing a carpal tunnel synovial biopsy during open carpal tunnel release (CTR). This has led to misconceptions about the diagnostic utility of synovial biopsy and the clinical evaluation of suspected amyloidosis. Controversy over carpal tunnel biopsy is exacerbated by minimally invasive advances in CTR procedures. This current perspective aims to determine the role of carpal tunnel synovial biopsy in amyloidosis and provide an update for hand surgeons regarding the nuances of amyloidosis. We conclude that carpal tunnel synovial biopsy should not be performed without CTS symptoms but only in patients meeting criteria for open CTR such as in those with severe symptoms which have failed nonoperative treatment and minimally invasive procedures are contraindicated. A screening approach for amyloidosis is proposed in patients presenting with CTS symptoms. Despite advances in the understanding, treatment, and diagnosis of amyloidosis, there remains a need for accurate, specific, and sensitive diagnostic tests.

A Comparison of Tenosynovial and Transverse Carpal Ligament Biopsy for Amyloid Detection in Open Carpal Tunnel Release

PURPOSE

Our purpose was to compare differences in the incidence of amyloid deposition in tenosynovium (TS) versus transverse carpal ligament (TCL) biopsies obtained during open carpal tunnel release. We hypothesized that the incidence of amyloid would be similar between TCL and TS when obtaining both specimens from the same patient.

METHODS

All primary, elective open carpal tunnel release cases that underwent biopsy for amyloid between January 2022 and September 2023 were reviewed. Tenosynovial and TCL specimens were independently evaluated by a pathologist to assess for amyloid. Demographic data were collected, and incidence of amyloid deposition was compared between the two samples. Agreement statistics, sensitivity, and specificity were calculated for TCL, using TS as the reference standard.

RESULTS

A total of 196 cases met either Tier 1 (n=180) or Tier 2 (n=16) biopsy criteria. Forty-eight cases were excluded for missed biopsies or laboratory processing errors, leaving 148 cases available for analysis. Amyloid deposition was present in 31 out of 148 (21%) TS specimens and 33 out of 148 (22%) TCL specimens. Overall, the results of the TS biopsy agreed with TCL biopsy in 138 out of 148 cases (93%). In the 10 cases for which the results of the TCL and TS biopsy differed, six cases had (+) TCL and (-) TS, and four cases had amyloid deposition in TS without evidence of deposition in the TCL. Sensitivity and specificity values for the TCL specimen were 87% and 95%, respectively. Positive and negative predictive values were 82% and 97%, respectively.

CONCLUSIONS

For cases of open carpal tunnel release undergoing biopsy, amyloid deposition was noted in 21% of TS specimens and 22% of TCL specimens. Results of TS and TCL biopsies obtained from the same patient agreed in 93% of cases. Single-source biopsy for amyloid represents a reasonable diagnostic approach. Future cost analyses should be performed to determine whether the addition of two biopsy sources to improve diagnostic accuracy is justified.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Prevalence of transthyretin amyloidosis in patients undergoing carpal tunnel surgery: a prospective cohort study and risk factor analysis

Transthyretin amyloidosis is a frequent cause of heart failure, resulting from an accumulation of abnormal proteins in the myocardium. Recent research has highlighted the importance of early diagnosis to enhance the effectiveness of specific treatments. Extra-cardiac symptoms may precede several years before cardiac complications, with carpal tunnel syndrome often considered a red flag. The aim of this prospective, observational cohort study was to determine the incidence rate of positive synovial biopsies for transthyretin amyloidosis in patients aged 60-80 years undergoing carpal tunnel decompression, and to identify risk factors. The diagnosis of transthyretin amyloidosis was confirmed through the analysis of synovial tissue biopsies using Congo Red and immunohistochemical staining. The study included 254 patients, with an 18.5% prevalence of transthyretin amyloidosis. Risk factors for positive test results were identified as male sex, trigger finger, hearing disorders and valve disease. A predictive analysis using logistic regression yielded a probability model for individuals belonging to the positive group.Level of evidence III.

Results of Implementation of Amyloidosis Screening for Patients Undergoing Carpal Tunnel Release

PURPOSE

Many patients with amyloidosis undergo carpal tunnel release (CTR) before amyloidosis diagnosis and before developing cardiac or other serious disease manifestations. The purposes of this study were to examine if our patient population had a similar prevalence of positive amyloidosis diagnoses to that in prior studies and to describe the results of implementing a screening program for amyloidosis.

METHODS

We retrospectively reviewed the biopsy results and subsequent interventions for all patients who underwent screening tenosynovial biopsy during CTR from March 2020 through December 2021. Amyloid screening was offered to patients who met the criteria for increased risk of disease using an appropriateness screening algorithm.

RESULTS

Seventy-five (48%) of 156 patients who underwent CTR met the eligibility criteria for amyloidosis testing. Of the 62 patients who agreed to undergo tenosynovial biopsy, 14 had amyloid-positive biopsy specimens (10 men and 4 women). All patients with positive tenosynovial biopsies had bilateral carpal tunnel syndrome and wild-type transthyretin amyloid subtype. One patient was diagnosed and started treatment for otherwise asymptomatic cardiac amyloidosis.

CONCLUSIONS

The incidence of amyloid-positive tenosynovial biopsy results from CTR was 22.5% in patients using the criteria from an appropriateness screening algorithm, which was higher than previously reported. Implementation of a screening program for patients undergoing CTR requires a multidisciplinary approach and may result in early diagnosis and lifesaving interventions for patients with amyloidosis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Differential diagnosis/symptom prevalence study, II.

Breakthrough advances enhancing care in ATTR amyloid cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) has been traditionally considered a rare and inexorably fatal condition. ATTR-CM now is an increasingly recognized cause of heart failure (HF) and mortality worldwide with effective pharmacological treatments. Advances in non-invasive diagnosis, coupled with the development of effective treatments, have transformed the diagnosis of ATTR-CM, which is now possible without recourse to endomyocardial biopsy in ≈70 % of cases. Many patients are now diagnosed at an earlier stage. Echocardiography and cardiac magnetic resonance have enabled identification of patients with possible ATTR-CM and more accurate prognostic stratification. Although radionuclide scintigraphy with 'bone' tracers has an established diagnostic value, the diagnostic performance of the bone tracers validated for non-invasive confirmation of ATTR-CM may not be equal. Characterising the wider clinical phenotype of patients with ATTR-CM has enabled identification of features with potential for earlier diagnosis such as carpal tunnel syndrome. Therapies able to slow or halt ATTR-CM progression and increase survival are now available and there is also evidence that patients may benefit from specific conventional HF medications. Cutting-edge research in the field of antibody-mediated removal of ATTR deposits compellingly suggest that ATTR-CM is a truly reversible disorder, bringing hope for patients even with advanced disease. A wide horizon of possibilities is unfolding and awaits discovery.

A Comparison of Amyloid Deposition in Endoscopic and Open Carpal Tunnel Release

PURPOSE

Previous investigations assessing the incidence of amyloidosis detected with biopsy during carpal tunnel release (CTR) have focused on open CTR (OCTR). Prior authors have suggested that biopsy may be more technically challenging during endoscopic carpal tunnel release (ECTR). Our purpose was to compare differences in the incidence of amyloid deposition detected during ECTR versus OCTR.

METHODS

We reviewed all primary ECTR and OCTR during which a biopsy for amyloid was obtained between February 2022 and June 2023. All procedures were performed by five upper-extremity surgeons from a single institution. Congo red staining was used to determine the presence of amyloid deposition in either the transverse carpal ligament (TCL) or tenosynovium. All positive cases underwent subtype analysis and protein identification through liquid chromatography-tandem mass spectrometry. Baseline demographics were recorded for each case, and the incidence of positive biopsy was compared between ECTR and OCTR cases.

RESULTS

A total of 282 cases were included for analysis (143 ECTR and 139 OCTR). The mean age was 67 years, and 45% of cases were women. Baseline demographics were similar except for a significantly higher incidence of diabetes in OCTR cases (13% vs 33%). Overall, 13% of CTR cases had a positive biopsy. There was a statistically significant difference in the incidence of amyloid deposition detected during biopsy in ECTR cases (3.5%) compared with OCTR cases (23%).

CONCLUSIONS

Biopsy performed during ECTR may result in a lower incidence of amyloid detection. Future basic science investigation may be necessary to determine histologic differences between tenosynovium proximal and distal to the leading edge of the TCL. When surgeons plan a biopsy during surgical release of the carpal tunnel, an open approach may be advantageous.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Amyloidosis and Considerations for the Hand Surgeon

Amyloidosis can lead to cardiac, renal, and other multiorgan failure. New treatments have become available that can prolong survival but rely on early diagnosis. Manifestations of amyloidosis in hand surgery include carpal tunnel syndrome, trigger finger, peripheral neuropathy, and spontaneous distal biceps rupture. Often, these can predate systemic amyloidosis, offering hand surgeons an opportunity to diagnose patients with amyloidosis before systemic disease, refer them for treatment, and potentially alter disease course and prolong survival. In this review, we describe the pathophysiology and two most common subtypes of amyloidosis seen by hand surgeons. We provide guidance on biopsy practices and referral for patients with amyloidosis. Lastly, we provide a brief overview of the treatments for amyloidosis and their effect on disease course.