An analysis of the flexor synovium in idiopathic carpal tunnel syndrome: Report of 625 cases This study was undertaken to determine the presence or absence of tenosynovitis in persons with idiopathic carpal tunnel syndrome. Eight hundred thirty-live consecutive operations for carpal tunnel syndrome were retrospectively reviewed, and 625 cases of idiopathic carpal tunncl syndromc were identified. Of these 96% (601) had a synovial tissue histologic diagnosis of benign fibrous tissue without inflammation, 4% (23) showed chronic inflammation, and 0.2% (1) revealed evidence of acute inflammation. We believe that tenosynovitis is not a part of the pathophysiologic process in chronic idiopathic carpal tunnel syndrome. Further histologic analysis of the flexor synovium for pathologic changes other than inflammation is needed. (J HAND SURG 1992;17A:I028-30.)

Charles D. Kerr, DO, Daryl R. Sybert, DO, and Narciso S. Albarracin, MD, Columbus, Ohio

T

he pathophysiology of idiopathic carpal tunnel syndrome is unclear. There is no consensus in the literature regarding the histologic characteristics of the flexor synovium in idiopathic carpal tunnel syndrome. I. 2 Several sources refer to tenosynovitis as a common etiologic condition.Y" whereas others state that tenosynovitis is a rare finding. 16-20 This study was undertaken to determine the presence or absence of tenosynovitis in idiopathic carpal tunnel syndrome.

Table 1. Clinical presentation Signs and symptoms Nocturnal numbness Numbness while holding a cup or newspaper Numbness while driving a car "Clumsiness" Numbness 24 hours a day

I

%

No.

77 65

481 407

45

284

45 14

280 90

Materials and methods Eight hundred thirty-five consecutive operations for carpal tunnel syndrome between Aug. 29, 1984, and Aug. 29, 1990, were reviewed for this report. All were performed by or under the direct supervision of one of us (C. D. K.). The carpal tunnel release procedure included a transection of the transverse palmar carpal ligament and flexor synovectomy. From the Departments of Orthopaedic Surgery and Pathology, Doctors Hospital, Columbus, Ohio. Received for publication May 29, 1991; accepted in revised form Feb. 7, 1992. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Charles D. Kerr, DO, 1313 Olentangy River Rd., Columbus, OH 43212.

3/1/37381

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Operati ve, office, and pathologic reports were reviewed. One hundred forty-two cases in which procedures were performed on patients whose carpal tunnel syndrome had a possible systemic origin, such as hypothyroidism, rheumatoid arthritis, sarcoidosis, gout, or diabetes mellitus, were excluded. In 26 cases procedures were performed because of wrist fractures or an anatomic anomaly, such as an anomalous muscle, giant cell tumor, lipoma, enlarged patent median artery, or severe scar formation in revision procedures. These were also excluded, as were 42 cases in which no synovial specimen was submitted for analysis. The study population therefore consisted of 625 patients with signs and symptoms of idiopathic carpal tunnel syndrome. Clinical details are in Table 1. Ninetythree percent of the patients had a positive Phalen's test,?' and 73% had a positive Tinel sign for the median

Vo!. 17A, No.6 November 1992

Flexor synovium ill idiopathic carpal tunnel syndrome

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Table II. Associations with chronic inflammation

Numbness 24 hours a day Thenar atrophy Average duration of conservative treatment (rna)

Total

Chronic

No

study

inflammation

inflammation

43% (10) 22% (5) 26

13% (80) 7% (39)

14% (90) 7% (44)

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nerve at the wrist. 22 Seven percent had thenar atrophy, and 4% had static two-point discrimination greater than 15 mm on clinical testing. Ninety-nine percent underwent electrophysiologic diagnostic studies (EMG/NCY), of which 98% confirmed carpal tunnel syndrome. All signs, symptoms, and EMG/NCV results that were not specifically noted in the records were considered not present or not performed. The average age at the time of surgery was 43 years (range, 18 to 86). Fifty-seven percent of the surgical procedures were performed on the right hand. Fiftyfive percent were performed on the dominant hand. Women made up 75% of this study population. Sixtythree percent of the patients had bilateral carpal tunnel syndrome. One percent (seven) of the cases involved reoperations. Failure of conservative therapy was documented in 93% of the cases. The average interval from onset of symptoms to surgical treatment was 35 months. Seventy-four associated operations were performed in 68 cases. Gross operative findings included a postdecompressive blush of the median nerve in 72%, a significant hourglass deformity in 14%, and what was subjectively believed to be abnormally thick synovium in 92%. Synovial biopsy specimens were submitted to the pathology laboratory in 10% buffered formalin fixative. Hematoxylin-eosin-stained slides were prepared and examined by a pathologist. One hundred sixty-two random cases were rereviewed by the chairman of the Pathology Department (N. S. A.) to verify the consistency of the initial pathology review. The histologic interpretation at rereview failed to reveal any inconsistency when compared with the original pathologist's finding with specific regard to inflammation. Results Benign fibrous tissue without evidence of inflammation was demonstrated histologically in 96% of the cases. Evidence of chronic inflammation as defined by

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the presence of lymphocytes, macrophages, or plasma cells as well as proliferation of fibroblasts and in many instances small blood vessels was found in 4% of the cases." Evidence of acute inflammation as defined by the presence of fibrin on the synovial surface andlor infiltration by neutrophils was found in 0.2% (one) of the cases." The signs and symptoms at presentation of the 23 patients with chronic inflammation were reviewed. Although 14% of the patients in the entire study complained of 24-hour-a-day numbness,.43% (lO) of those with chronic inflammation said that they experienced numbness 24 hours a day (p ::: 0.001, Fisher's Exact Test). Thenar atrophy was noted in 7% of the study group and in 22% (5) of the patients with chronic inflammation (p = 0.0239). The average time from onset of symptoms to surgery was 26 months in this subgroup, compared with 35 months in the total study population (Table II). Discussion Several recent histologic studies of the flexor tenosynovium in idiopathic carpal tunnel syndrome have noted the absence of an inflammatory reaction. 17-20 Our study supports these authors' observations. We evaluated the tenosynovium of patients who underwent surgical release of the transverse carpal ligament, in most of whom a course of conservative therapy, including antiinflammatory medication, had been unsuccessful. Histologic characteristics in persons with early carpal tunnel syndrome or in those patients who respond to conservative treatment have not been determined. The small percentage of patients in whom chronic inflammation was seen appeared to have a more fulminant carpal tunnel syndrome, with more thenar wasting and 24-hour numbness and with less time from onset of symptoms to surgery when compared with patients without inflammation. Edema and vascular sclerosis have been seen in the tenosynovium in persons with idiopathic carpal tunnel

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Kerr et al.

syndrorne.F'' We did not specifically search these abnormalities in the histologic review part of this study. Synovial "thickening" has been noted at the time of surgery and may play a role in the pathophysiology, but it has not been quantified. Tenosynovitis does not appear to play a role in chronic idiopathic carpal tunnel syndrome. Additional studies are needed to further delineate the cellular and biochemical nature and the amount of flexor tenosynovium in normal persons and in patients with early and chronic idiopathic carpal tunnel syndrome. We acknowledge the assistance of the Ohio State University Department of Statistics.

REFERENCES 1. McGrath MH. Local steroid therapy in the hand. J HAND SURG 1984;9A:915-21. 2. Tanzer RC. The carpal tunnel syndrome: a clinical and anatomical study. J Bone Joint Surg 1959;41A:626-34. 3. Bole GG. Nonarticular rheumatism. In: Wyngaarden JB, Smith LH Jr. Cecil's textbook of medicine. Philadelphia: WB Saunders, 1988:2047. 4. Bullough PG, Vigorita VJ. Atlas of orthopaedic pathology. Baltimore; University Park Press, 1984;14.5. 5. Conklin JE, White WL. Stenosing tenosynovitis and its possible relation to carpal tunnel syndrome. Surg Clin North Am 1960;40;531-40. 6. Wilson JO, Braunwald E, Isselbacher KJ, et al. Harrison's principles of internal medicine. 12th ed. New York: McGraw-Hill, 1991:1487. 7. Kelley WN, Harris EO Jr, Ruddy S, Sledge CB. Textbook of rheumatology. 3rd ed. Philadelphia: WB Saunders, 1989;1845. 8. Lipscomb PRo Tenosynovitis of the hand and wrist: carpal tunnel syndrome, de Quervain's disease, trigger digit. Clin Orthop 1959;13:164-81. 9. Lister G. The hand-diagnosis and indications. 2nd ed. New York: Churchill Livingstone, 1984:192.

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10. Milford L. Carpal tunnel and ulnar tunnel syndromes and stenosing tenosynovitis. In: Crenshaw AH. Campbell's operative orthopaedics. St. Louis: CV Mosby, 1987:459. II. Phalen GS, Kendrick n. Compression neuropathy of the median nerve in the carpal tunnel, JAMA 1957;164:52430. 12. Scott JT. Copeman's textbook of the rheumatic diseases. 5th ed. New York: Churchill Livingstone, 1978:993. 13. Taleisnik J. Compression neuropathies of the upper extremity. In: Chapman MW. Operative Orthopaedics. Philadelphia: JB Lippincott, 1988: 1346. 14. Turek S. Orthopaedic principles and their application. 4th ed. Philadelphia; JB Lippincott, 1984: 1083. 15. Weissman B, Sledge C. Orthopaedic radiology. Philadelphia: WB Saunders, 1986: 164. 16. Youmans JR. Neurological surgery. Philadelphia: WB Saunders, 1973:1146. 17. Faithfull DK, Moir DH, Ireland 1. The micropathology of the typical carpal tunnel syndrome. J HAND SURG 1986;11B:131-2. 18. Schuind F, Ventura M, Pasteels JL. Idiopathic carpal tunnel syndrome: histologic study of flexor tendon synovium. J HAND SURG 1990;15A:497-503. 19. Wilhelm K, Feldmeier CH, Briegel J, Meister P. Genese des Karpaltunnel-Syndroms; pathologisch anatomische studie, Munch Med Wochenschr 1982;124:661-2. 20. Fuchs PC, Nathan PA, Myers LO. Synovial histology in carpal tunnel syndrome. J HAND SURG 1991;16A:753-8. 21. Phalen GS. The carpal tunnel syndrome: seventeen years experience in diagnosis and treatment of 654 hands. J Bone Joint Surg 1966;48A;211-28. 22. Tinel 1. Le Signe du "Fourmillement" dans les lesions des nerfs. In: Spinner M. Injuries to the major branches of peripheral nerves of the forearm. 2nd ed. Philadelphia; WB Saunders, 1978:8-13. 23. Robbins SL, Cotran RS, Kumar V. Pathologic basis of disease. 3rd ed. Philadelphia: WB Saunders, 1984:4161.

An analysis of the flexor synovium in idiopathic carpal tunnel syndrome: report of 625 cases.

This study was undertaken to determine the presence or absence of tenosynovitis in persons with idiopathic carpal tunnel syndrome. Eight hundred thirt...
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