Carpal Tunnel Syndrome

Etiology, pathogenesis and management of this nerve compression syndrome described in this presentation.

1. CARPAL TUNNEL SYNDROME DR G AVINASH RAO FELLOW HAND AND MICROSURGERY DEPARTMENT OF PLASTIC SURGERY, SKIMS , SRINAGAR

2. INTRODUCTION Carpal tunnel syndrome– most common compressive neuropathy of upper extremity. Symptoms of median nerve compression– were first described (distal radius fractures) by Sir James Paget in 1854. The term carpal tunnel--- coined— Mersch 8 decades later.

3. Anatomy Carpal tunnel is bordered dorsally by concave arch of carpus & volarly by transverse carpal ligament (TCL). 10 structures pass--- 9 flexor tendons & median nerve. Median nerve is most superficial structure, entering just radial to midline.

4. Recurrent motor branch. It usually originates in extraligamentous position distal to TCL.  Extraligamentous (46%)  Subligamentous (31%)  Transligamentous (23%)

5. The PALMAR CUTANEOUS BRANCH OF THE MEDIAN NERVE lies between the FCR and PL tendons in the distal forearm, but its branches may be found upto 6mm ulnar to the thenar crease in the palm .

6. ETIOLOGY Idiopathic Women > men (2-3:1) Age – 30-60 (MC) Use of vibrating hand tools, smokers, High body mass index (BMI) – obesity. Wrist ratio  – If the anterior to posterior distance is  ≥70%  of the medial to lateral distance, there is a significant association with idiopathic CTS. Pregnant women – Symptoms relieve after Delivery, Children – Rare ( macrodactyly , lysosomal storage disorders, strong family history – predisposes ).

7. Trauma caused by repetitive hand motions especially in works requiring repeatetive forceful finger and wrist flexion and extension. Habitual sleeping posture in which the wrist is kept acutely flexed.

8. FACTORS INVOLVED IN PATHOGENESIS OF CTS. Kerwin G, Williams CS, Seiler JG : The pathophysiology of carpal tunnel syndrome, Hand Clin 12:243, 1996 .

9. Pathogenesis Median nerve is susceptible to compression within carpal canal because of unyielding fibro osseous borders. Normal pressure--- 2.5mm Hg. Elevation of carpal tunnel pressures impedes epineurial blood flow, and nerve function is impaired A decrease in epineural blood flow & edematous changes occur--- pressure reaches 20-30 mm Hg. At > 30 mm Hg, nerve conduction diminishes, continued rise--- complete nerve block.

10. Diagnosis of CTS History & physical examination are the key. CTS is primarily a clinical Diagnosis. Pain (nocturnal > day) , deep aching/throbbing Numbness , tingling and Paresthesia in typical median nerve distribution. Daytime paresthesias – elicited with activities involving prolonged wrist flexion/ extension. Shaking & Exercises--- sometimes REDUCE symptoms. B/L CTS - Check opposite hand for early diagnosis Atypical presentation– paresthesias in radial digits but with pain radiating proximally along median nerve to forearm, elbow sometimes shoulder.

11. CHRONIC CTS Chronic median nerve compression--- gritty or numb sensation in fingers. grip & pinch weakness, & diminished finger dexterity with H/o dropping objects (Prominent Thenar wasting). RSD/ CRPS.

12. Clinical Evaluation Thorough physical examination--- including cervical spine & entire upper extremities. (Double crush phenomenon) Soft tissues are assessed for skin & muscle atrophy. Cold intolerance, dryness & unusual textures in radial digits signify disruption of sympathetic fibres carried by median nerve.

13. TINEL’S SIGN (NERVE PERCUSSION)

14. Tinel’s sign The examiner taps directly over the carpal tunnel with his or her long and index fingers. A positive test consists of paresthesia or pain in a median nerve distribution.

15. Phalen’s test The patient’s wrist is held in a flexed position for upto a minute or until onset of symptoms. A positive test consists of the onset of numbness or paraesthesia in the median nerve distribution.

16. Carpal tunnel compression test / Durcan’s Test The examiner applies direct pressure to the carpal tunnel with his or her thumb for upto 1minute or until onset of symptoms. A positive test consists of the onset of numbness or paresthesia in the median nerve distribution. More specific (90%) and more sensitive (87%) than either the Tinel or Phalen test.

17. Semmes-Weinstein monofilaments

18. Semmes-Weinstein monofilaments Monofilament evaluator size was started from 2.83 to 6.65. 2.83 – Green – Normal 3.61 – Blue – Diminished light touch 4.32 – Purple – Diminished protective sensation 4.56 – Red – Loss of protective sensation

19. Two-point discrimination

20. Two-point discrimination STATIC Determine minimal separation of two distinct points when applied to palmar fingertip Innervation density of slow-adapting fibers Failure to determine separation of at least 5 mm DYNAMIC As above, with movement of the points Innervation density of fast-adapting fibers Failure to determine separation at least 4 mm BOTH INDICATE ADVANCED NERVE DYSFUNCTION

21. Katz & Stirrat hand diagram Ryan P. Calfee, MD, Ann Marie Dale, PhD, Daniel Ryan, MS, Alexis Descatha, MD, Alfred Franzblau, MD, Bradley Evanoff, MD

22. The MOST SENSITIVE TESTS - Durkan nerve compression, the hand diagram score , night pain , and Semmes-Weinstein testing after a Phalen test . The MOST SPECIFIC TESTS were the hand diagram and Tinel sign .

23. GRAHAM B’S CTS – 6 CRITERIA

24. Szabo et al determined a probability of 0.86 in correctly diagnosing CTS in presence of positive median nerve compression test, positive hand diagram, night pain, & abnormal Semmes-Weinstein monofilament testing.

25. NCS & EMG It tells weather pt has the disease It is useful to judge severity of disease Prognostic value after treatment If NCS shows axonal loss then surgery has to be advised. Diagnose incomplete release or Iatrogenic Nerve injury Double crush syndrome (cervical myelopathy / pronator syndrome) Medicolegal issues If pt has obvious thenar muscle wasting.

26. NCS &EMG According to the American Association of Electrodiagnostic Medicine recommendations: Median nerve distal sensory latency , upper limit of normal – 3.6 ms Difference between the median and ulnar nerve distal sensory latencies, upper limit of normal – 0.4 ms Distal motor latency over the thenar , upper limit of normal – 4.3 ms Median motor nerve conduction velocity – lower limit of normal – 49 m/s Median sensory nerve conduction velocity – lower limit – 49 m/s

27. SONOGRAPHY Non invasive Presence of median nerve edema Measurements of cross-sectional area of median nerve at carpal tunnel inlet proximally and outlet distally were taken The shape, size, echogenecity and relationship of median nerve to overlying retinaculum Amount of synovial fluid and any presence of masses (cysts /lumps) Anatomy of median nerve and continuity Considered in reccurent cases (not routinely done)

28. MEASUREMENT OF CSA OF THE MEDIAN NERVE

29. The cut-off value for pathological cross-sectional area of median nerve is 9.4 mm square. Mild – 9.4 to 11.3 Moderate –11.3 to 13.5 Severe – 13.5 and above

30. OTHER INVETIGATIONS Imaging studies Three-view radiographs of the wrist ( posteroanterior , lateral, oblique) plus carpal tunnel view: obtained when there is antecedent wrist trauma. MRI (diffusion tensor imaging) - not routinely used for diagnosis. A major advantage of MRI is its high soft-tissue contrast, which gives detailed images of bones and soft tissues. Serologic studies No blood tests specifically support diagnosis of CTS Diabetes & Hypothyroidism are common diseases--- FBS & Thyroid function test.

31. AAOS GUIDELINES – for Non Sx Rx Considered in early CTS. Trial of conservative Rx for 2-7weeks if it fails, attempt one more time. Local Sterid and splint recommended prior to surgery Neurotonics – Placebo affect Massage / acupunture /any other conservative options not recommended

32. Kaplan, Glickel, and Eaton - five important factors in determining the success of nonoperative treatment: age older than 50 years, duration longer than 10 months, constant paresthesia , stenosing flexor tenosynovitis , a positive Phalen test result in less than 30 seconds. 0 - Two thirds of patients were cured by medical treatment 1 - 59.6% were cured. 2 - 83.3% when two factors were noted 3 - 93.2% did not experience any improvement No patient with four or five factors was cured by medical management .

33. Treatment – Conservative options Nerve Gliding Exercises. Local Triamcinolone (steroid) Injection Night Splints. Strict control of medical illness Treatment of double crush syndrome contraversial Oral medications Diuretics, NSAIDs, oral corticosteroids & vitamin B6.--- thought to decrease interstitial fluid pressure within carpal canal .

34. Celiker et al compared the effectiveness of NSAIDs & splinting with corticosteriods injections in treating CTS. Found that both methods of treatment led to statistically significant improvement in symptoms at 2 months.

35. Aufiero et al cited several studies supporting & disproving the efficacy of vit B6. Only 2 studies were randomized & blinded in design- -- no improvement .

36. Corticosteroid injection Gelberman et al found single injection improved CTS symptoms in 76% of pts after 6 weeks. However only 22 % remained symptom free at 1 year. Effective in mild CTS symptoms,< 1 year,normal sensibilty testing & only minor electrodiagnostic study abnormalities.

37. Transient elevation in blood glucose can be anticipated--- thus a less soluble corticosteroid preparation (triamcinolone). Diabetic pts should be instructed to monitor their serum glucose. No absolute contradiction to injection during third trimester of uncomplicated pregnancy or healthy breast feeding woman.

38. Immobilization of wrist at night & intermittently during the day. Pressure in carpal tunnel is lowest with wrist in 2* -/+ 9* of extension & 2* +/- 6* of ulnar deviation. Splinting

39. Ultrasound Therapy In randomized study ultrasound improved symptoms at 2 weeks, 7 weeks, 6 months. However another study demonstrated no appreciable benefit at 2 weeks from this form of treatment.

40. Ergonomics Ergonomic changes---specialized desk chairs & computer keyboard proved to prevent CTS.

41. Exercises Nerve & tendon gliding exercises enhance venous blood flow & decrease pressure within carpal tunnel. Rozmaryn et al evaluated 240 pts with CTS, half of whom were instructed to perform nerve & tendon gliding exercises. Patients who did not do these exercises, 71 % eventually underwent carpal tunnel release surgery, in other group 43% had surgery.

42. AAOS GUIDELINES- for Sx Rx Regardless of technique used – complete release of Flexor Retinaculum is recommended Epineurotomy , Neurolysis, Tenosynovectomy are not recommended in all cases Wrist immobilization is not required

43. Surgical treatment - Options OPEN CTS RELEASE MINI OPEN CTS RELEASE ENDOSCOPIC CTS RELEASE - SINGLE PORTAL (AGEE) - TWO PORTAL (CHOW)

44. OPEN CTS

45. OPEN CTS RELEASE The palmar incisions should be well ulnar. A curved incision ulnar and parallel to the thenar crease but the palmar cutaneous branch of the median nerve proximally may be more at risk of injury. Maintain longitudinal orientation so that the incision is generally to the radial border of the ring - fourth ray. Incise and reflect the skin and subcutaneous tissue. Identify the palmar fascia from the wrist flexion crease distally.

46. And the distal forearm antebrachial fascia proximally by subcutaneous blunt dissection. Split the palmar fascia and expose the underlying transverse carpal ligament and carefully divide it and avoid damage to the median nerve and its recurrent branch Fibers of the transverse carpal ligament can extend distally farther than expected. The flexor retinaculum includes the distal deep fascia of the forearm proximally, the transverse carpal ligament, and the aponeurosis between the thenar and hypothenar muscles. A successful carpal tunnel release usually requires division of all these components .

47. MINI OPEN CTS INCISION

48. Mark surgical incision with a skin pen The longitudinal incision - just distal to the distal wrist flexion crease and slightly ulnar to the midline of the wrist. Extend Distally - 2.0 to 3.0 cm in line with the third web space. Expose the transverse carpal ligament - by splitting the parallel palmar fascia fibers and retract hypothenar fat ulnarly. Intrinsic muscles obscure the midline of the TCL and can be released from their origin and reflected away from the underlying TCL.

49. Carefully open the carpel tunnel by division of the TCL with a no15 blade. Ensure complete release. The TCL divided in such a way that 3 to 4 mm of it is left attached to the hamate hook to avoid flexor tendon ulnar subluxation. Make sure the contents of the carpal tunnel are not adherent to the undersurface of the TCL. Close the incision in routine fashion and apply a compressive dressing.

50. Endoscopic carpal tunnel release Problems related to endoscopic carpal tunnel release include a technically demanding procedure; a limited visual field that prevents inspection of other structures; The vulnerability of the median nerve, flexor tendons, and superficial palmar arterial arch; The inability to control bleeding easily; The limitations imposed by mechanical failure.

51. Agee, McCarroll , and North - 10 guidelines for the single-incision ECTR Know the anatomy. Never over commit to the procedure. Ascertain that the equipment is working properly. If scope insertion is obstructed, abort the procedure. Ascertain that the blade assembly is in the carpal tunnel and not in the Guyon canal. If a clear view cannot be obtained, abort the procedure. Do not explore the carpal canal with the scope If the view is not normal, abort the procedure. Stay in line with the ring finger. When in doubt, get out.

52. CONTRAINDICATIONS FOR ECTR ( DESCRIBED BY CHOW) The patient requires neurolysis, tenosynovectomy, Z-plasty of the transverse carpal ligament, or decompression of the Guyon canal. The surgeon suspects a space-occupying lesion or other severe abnormality of the muscles, tendons, or vessels in the carpal tunnel. The patient has localized infection or severe hand edema, or the vascular status of the upper extremities is tenuous.

53. Fischer and Hastings further added Revision surgery for unresolved or recurrent carpal tunnel syndrome Anatomic variation in the median nerve. Previous tendon surgery or flexor injury that would cause scarring in the carpal tunnel. Limitation of wrist extension is (endoscopic instruments cannot be introduced into the carpal tunnel). AS CONTRAINDICATIONS FOR ECTR.

54. AZEE TECHNIQUE

55. AZEE

56. CHOW TECHNIQUE

57. Open vs endoscopic Open vs endoscopic Endoscopic– shorten recovery time However no substantial differences in final outcome. One study in 25 pts, one hand open & another endoscopic was done 3 months later, no significant differences With ECTR - Less palmar scarring and ulnar “pillar” pain, rapid and complete return of strength, and return to work and activities at least 2 weeks earlier.

58. Post-OP Rehabilitation Wrist immobilisation after carpal tunnel surgery--- no benefit in pain relief or surgical outcome. Active motion exercises of wrist & fingers are to be encouraged .

59. SURGICAL COMPLICATIONS Median nerve injury. Hypertrophic scar formation. Pillar pain. Injury to superficial arterial arch. Incomplete release of TCL. Tendon adhesions. Infections. Wound hematoma. Finger stiffness. Recurrence.

60. ECTR COMPLICATIONS Intraoperative injury to flexor tendons. Injury to median, ulnar, and digital nerves. Injury to superficial palmar arterial arch. ECTR - Technically demanding procedure

61. Young pt with symptoms of CTS and decreased grip stength consider – CTS release + Flexor Tenosynovectomy . If symptoms persists in previously operated case (tingling and Paresthesia with Tinels positive) – Consider sonography - incomplete release / Neuroma in continuity formation 2 to iatrogenic injury Elderly with chronic CTS and thenar wasting and inability to do finer activities – consider CTS with Tendon Transfer for thumb opposition ( opponensplasty ) Considerations before Sx

62. UNCOMMON – REQUIRE ATTENTION BE AWARE OF POTENTIAL ANOMALIES: connections between the FPL and the index FDP tendon; Anomalous FDS;PL, hypothenar, lumbrical muscle bellies; Median and Ulnar nerve branches and interconnections. RARE – BIFID MEDIAN NERVE

63. Summary CTS– common problem. Several risk factor are associated. Thorough history & physical examination is the key. Non-surgical & surgical techniques are beneficial. Both open & endoscopic have same results. Look for S/O CRPS (RSD) in Chronic cases, Before surgery.