E n d o s c o p i c Ca r p a l Tu n n e l Release Torben B. Hansen, MD, PhDa,b,*, Haider Ghalib Majeed, MDa KEYWORDS Median nerve compression Carpal tunnel syndrome Endoscopic carpal tunnel release Minimal invasive surgery
KEY POINTS Minimal invasive surgery Effective local anesthetic surgery Reduces rehabilitation time No difference compared with open surgery after 3 months Operation costs higher than with open surgery May be more cost-effective than open surgery because of faster rehabilitation
INTRODUCTION Nature of the Problem Carpal tunnel syndrome (CTS) is a common compression neuropathy arising from increased pressure in the carpal tunnel. Wrist fracture, trauma, and vibration tools may lead to CTS, but in most patients the condition is idiopathic. If conservative treatment fails, a procedure to release the carpal tunnel is normally indicated. During a carpal tunnel release (CTR), the surgeon divides the flexor tendon retinaculum, decompressing the pressure within the carpal tunnel, a technique introduced more than 60 years ago.1 In the conventional open CTR (OCTR), the surgeon dissects directly down to the flexor tendon retinaculum through a skin incision extending from the wrist creases to the middle of the palm. The retinaculum is then split using a scalpel or scissors, resulting in decompression of the carpal tunnel. This technique necessitates an incision in the palm, which can be painful and limit recovery.
The introduction of arthroscopy for joint surgery generated the idea that arthroscopic technology could be used to treat CTS with minimal subcutaneous dissection. This idea led to the development of the endoscopic CTR (ECTR),2 which divides the retinaculum through small portals without dissecting in the subcutaneous space above the retinaculum. Two different techniques were introduced: the 2-portal system by Chow and Hantes3 and 1-portal systems by Okutsu2 and by Agee and colleagues.4 Since the initial advent, other techniques and devices have been developed, but all are variations of the original systems.
INDICATIONS/CONTRAINDICATIONS Before any operative procedure, the first step is to ensure that the diagnosis of CTS is correct (Table 1). A history and physical examination often confirm the diagnosis, and the use of preoperative nerve conduction studies (NCSs) may reduce the risk of misdiagnosing symptoms
Disclosure: This work did not receive financial support. a Section of Hand Surgery, Department of Orthopaedics, Regional Hospital Holstebro, Laegaardvej 12, Holstebro DK-7500, Denmark; b Department of Clinical Medicine, Aarhus University, Brendstrupga˚rdvej 100, 8200 Aarhus N, Aarhus C DK-8000, Denmark * Corresponding author. Department of Clinical Medicine, Aarhus University, Brendstrupga˚rdvej 100, 8200 Aarhus N, Aarhus C DK-8000, Denmark. E-mail address: [email protected] Hand Clin 30 (2014) 47–53 http://dx.doi.org/10.1016/j.hcl.2013.08.018 0749-0712/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
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Table 1 Indications/contraindications Primary Indication Idiopathic CTS
a
Relative Contraindicationa CTS secondary to trauma/ fracture CTS associated with inflammatory disease Recurrent CTS Severe obesity Anticoagulated
Consider OCTR instead.
related to other diseases, such as cervical nerve compression. Most patients are candidates for ECTR because idiopathic CTS can be safely treated with this technique. ECTR decreases the acute morbidity after CTR, and thus, some have advocated performing simultaneous ECTR in patients with bilateral disease,5 depending on the severity of the symptoms. Fehringer and colleagues6 found a decrease in the time to return to work in the simultaneous group compared with the staged group, and the simultaneous group also required fewer physician visits. Overall, patient satisfaction was equal, and the use of simultaneous surgery seems to be of economic benefit to both the patient and the hospital, reducing the cost of operation and sick leave. There are several instances in which ECTR should be approached with caution. The first group is those patients with CTS secondary to inflammatory diseases, such as rheumatoid arthritis. These patients may have synovial adhesions and hypertrophy, which can interfere with the introduction of the endoscopic device and impair the visibility in the carpal tunnel. Also, ECTR should be considered carefully in patients with a history of wrist fractures, because their previous trauma may have resulted in scarring and changes in the bony architecture of the carpal tunnel. For these patients, preoperative radiographic examination with carpal tunnel view may identify posttraumatic spaceoccupying changes. There has also been concern about ECTR in patients who have had a previous CTR. It is possible to perform ECTR as a revision surgery for recurrent CTS.7–9 The most common cause of recurrence is incomplete division of the retinaculum, and this may be treated with ECTR. However, the surgeon should always consider that the cause of the failure of the previous surgery might have been a compressive lesion, such as a lipoma, an osteophyte, or an arteria mediana. These anatomic variants may not be found during an endoscopic procedure, and if
they are suspected, the conventional open technique should be chosen. Also, fibrous scarring may cause compression and recurrence of CTS and should not be treated with ECTR. So, ECTR should be used with caution in recurrent cases and reserved for cases in which the patient had relief after the first surgery but had recurrence after several months. In general, the surgeon should use an open technique if any doubt exists regarding the cause of the recurrence. ECTR should be used with care in the severely obese patient, because a large palmar fat pad may protrude into the carpal tunnel, impairing vision during the endoscopic division of the retinaculum. In addition, in the obese patient, the tourniquet may fail, resulting in a need to convert to OCTR. Another group to approach with caution is patients taking anticoagulants. OCTR should be considered for these patients, because hemostasis is easier with this technique.
SURGICAL TECHNIQUE/PROCEDURE Preparation and Patient Positioning The patient is placed with the arm abducted on the operation table. The surgeon is positioned so that they can use the dominant hand for maneuvering the endoscope. Several anesthetic techniques have been described. Most commonly, the procedure is performed using local infiltration analgesia (LA) or in a regional block. General anesthesia is used only in patients who are unable to tolerate LA or block. LA is well tolerated, easy to manage, and has been proved to be more effective than a regional block, reducing costs and with less postoperative pain.8,10 We use the LA technique, which is simple and well tolerated. Ropivacaine 7.5 mg/mL or an equivalent local anesthetic may be used. The infiltration is performed with 4 mL administered in the proximal direction under the subcutaneous fascia of the forearm, 2 mL subcutaneously transversely in the distal wrist crease, and 4 mL subcutaneously in the palm (Fig. 1) along the crease between the thenar and the hypothenar. The tourniquet is then inflated to 80 mm Hg greater than systolic blood pressure 10 minutes after the administration of the local anesthetic and immediately before the skin incision. Good visibility during the endoscopic procedure is critical to reduce the risk of complications. Using LA with epinephrine reduces the bleeding only in the skin and not in the carpal tunnel. So a tourniquet should always be used, because bleeding inevitably impairs the vision during the procedure and leads to a highly increased risk of nerve damage.
Endoscopic Carpal Tunnel Release
Fig. 1. Infiltrating with local anesthetics.
Fig. 3. Preparing for insertion of the ECTR device.
Step 3
SURGICAL APPROACH Because we have only a limited experience with the 2-portal technique, the following description of the operative technique is based on the Agee (Microaire, Charlottesville, VA, USA) 1-portal technique. However, apart from the difference in number of portals, the main features of the procedures are the same.
Step 1 In the 1-portal technique, the incision is a transverse incision at one of the wrist creases (Fig. 2). A distal hinged fascia flap is prepared, followed by clearing synovial adhesions using a dissector. This strategy allows development of a portal down to the level of the median nerve (Fig. 3).
The knife is placed so that it rests upwards onto the retinaculum oriented along the axis of the ring finger. The endoscopic knife is introduced, and the distal border of the retinaculum localized. The distal border can be visualized by a change in color and is normally well defined. If there are any problems with the visibility and the retinaculum is difficult to define, then convert to an open procedure (“if in doubt get out”).
Step 4 Once the retinaculum is defined, the knife blade is engaged and the retinaculum is divided in distalproximal direction. While drawing the knife proximally (toward the surgeon), the focus is keeping the knife in intimate contact with the retinaculum; this prevents nerve or tendon interposition (Fig. 4).
Step 2 After the soft tissue is freed, the dilators are inserted. The dilators are inserted to ensure free mobility of the contents of the carpal tunnel, so that it is possible to freely move the knife above the tendons and nerve.
Fig. 2. Incision in the wrist crease.
Fig. 4. The view through the ECTR device showing the knife in intimate contact with the retinaculum.
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Hansen & Majeed Step 5 Next, you need to ensure a complete release. To assist with this goal, we have made a special instrument by bending a hook usually used for knee arthroscopy. We use this instrument for testing the tension of the retinaculum and retracting the fad-pad (Figs. 5 and 6). This maneuver reduces the risk of incomplete division of the retinaculum, which may lead to recurrence of the CTS. This maneuver also helps in assessing the distal border of the retinaculum by looking for the distal holdfast fibers of the flexor retinaculum described by Okutsu.2 These fibers tether the cut edges of the retinaculum so that it does not move freely and hang down after release. The presence of these fibers indicates that an incomplete division of the retinaculum should be suspected. In our experience, these fibers are easily assessed using the hook to test for tension and incomplete division. After dividing the retinaculum, it is important also to divide the proximal fascia edge at the portal, especially if the portal is placed at the distal wrist crease.
Step 6 The tourniquet may be deflated before the skin is sutured with interrupted nylon sutures or a continuous resorbable intracutaneous suture. After suturing the wound, additional Steri-Strips may be used. The use of intracutaneous suture may reduce pain in the first 24 hours compared with interrupted nylon sutures, but the difference is only small and the cosmetic appearance of the scar is equal after 3 months.11
POSTOPERATIVE CARE The hand should be immobilized in a light compressing boxer bandage (Fig. 7) for 24 to 48 hours to avoid bleeding in the carpal tunnel. After removal of the large bandage, the patient needs only a Band-Aid until the wound has healed after 10 to 12 days.
Fig. 5. The hook that may be used for retraction of a protruding fat pad and for testing the tension after dividing the retinaculum.
Fig. 6. The hook inserted in the carpal tunnel.
COMPLICATIONS AND MANAGEMENT There is a significant learning curve in ECTR, but Beck and colleagues12 found that the rates of conversion significantly diminished with increased surgeon and anesthesia experience. During this learning curve, patients may be at a higher risk of conversion to OCTR, but there is no increased morbidity. Because LA may increase the risk of impaired visibility during the procedure, it may be advised to use a regional block initially until the surgeon feels comfortable with the endoscopic technique. The complication most feared with ECTR is injury to a nerve. Most commonly, these injuries are a transient neuropraxia. For example, decompression of the carpal tunnel using ECTR may result in changes in pressure in the Guyon canal, leading
Fig. 7. Immobilization in a light compressing boxer bandage for 24 to 48 hours to avoid bleeding in the carpal tunnel.
Endoscopic Carpal Tunnel Release to Guyon canal syndrome, but these symptoms are normally brief.13 Transitory median nerve sensory disturbances also may occur after ECTR, probably because of compression, stretching, or manipulation of the median nerve during the operation. Although rare, the most serious complication is permanent nerve injury caused by cutting into the nerve.14,15 To avoid this complication, surgeons must be aware that neural variations arising from the ulnar aspect of the median nerve are common and these could put the nerve at risk for iatrogenic injury during either endoscopic or open release.16 To minimize risk of complications, the surgeon must be willing to convert to an OCTR if the situation is suboptimal. In particular, the risk for nerve injury is amplified if the visibility during the procedure is impaired. Thus, if bleeding is limiting the visibility during an ECTR, the surgeon should seriously consider converting to an open procedure. Another criterion for safe release of the flexor retinaculum using ECTR is that the contents of the carpal tunnel must be freely moveable by the endoscope. If the surgeon encounters a mechanical block or significant resistance during the introduction of the endoscope (which may be caused by synovial adhesions or an abnormality within the carpal tunnel), conversion to an open procedure is highly recommended. The surgeon may also encounter difficulties when introducing the endoscope in a small wrist. Uchiyama and colleagues17 found that tight access was experienced more frequently in younger patients and those with a small cross-sectional area at the hook-of-hamate level. These investigators found that ECTR was easily performed in older female patients. Although the younger patients were more challenging, this study did not identify a group of patients in whom ECTR should be avoided, and the conclusion was that no group should be excluded based on solely age, body size, or gender. As with any surgical procedure, postoperative bleeding may occur after ECTR, resulting in swelling of the hand and an increased risk of infection. To limit this risk, a light compressive bandage is recommended during the first 24 hours. Also, as mentioned earlier, for patients on anticoagulants, OCTR should be considered. Postoperative infection and reflex sympathetic dystrophy syndrome are rare complications14,15 and not specific to ECTR compared with hand surgery in general. Efficacy of ECTR to relieve carpal tunnel symptoms varies depending on the age of the patient, the severity of the CTS, and the duration of the nerve compression.18–20 However, complete lack of relief of the preoperative symptoms suggests
that the diagnosis may have been wrong or that there has been an incomplete release of the retinaculum. One concern with ECTR is an increase in risk of inadequate release because of limited visibility of the retinaculum when compared with the direct approach of OCTR. This risk is reduced with increasing experience with ECTR and by using our modified hook to help inspect for any residual compressive bands (see step 5). Repeat NCSs are helpful in evaluating patients who have not improved after surgery. Rotman and colleagues21 found that postsurgical changes in the distal motor latency of the median nerve were highly dependent on the prerelease latency. This sensitivity and specificity of an NCS can aid in determining the level of improvement in median nerve function after ECTR. An NCS performed 3 months after the operation should show some improvement compared with preoperative values. If not, the possibility of an incomplete division of the retinaculum should be suspected and reoperation considered. Overall, the literature has found ECTR to be a safe procedure. Hankins and colleagues’14 reported on a large series of patient and had only 1 nerve injury in 14,722 patients and a conversion rate to open procedure of 0.07%. In another series of 12,702 patients, Pajardi and colleagues15 had 6 nerve injuries (3 partial), 12 recurrences, and a conversion to open procedure of 0.46%. Benson and colleagues22 performed a meta-analysis of 80 publications, including 22,327 cases of ECTR and 5669 cases of OCTR release, and found that the proportion of complications was very low for CTR, performed either endoscopic or open. Thus, selection of CTR technique should be based on surgeon and patient preference.
POSTOPERATIVE CARE This section outlines our postoperative instructions after ECTR. To avoid wound infection, patients are advised to keep the wound away from dirt until the skin has healed after 10 to 14 days. Workers without hand-demanding tasks may work after removal of the compressing bandage after 24 to 48 hours. Workers with hand-demanding tasks may benefit from a sick leave of 10 to 14 days until the wound has healed. After the wound has healed, no specific restrictions are needed, and the patients are allowed to use the hand as much as pain and tenderness allow. Normally, no formal therapy is required. No routine controls are needed.
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Hansen & Majeed OUTCOMES ECTR has been extensively studied. Much of the focus has been on the impact of ECTR on postoperative recovery. In this section, several randomized controlled trials that have compared ECTR with OCTR are reviewed. Atroshi and colleagues23 performed a randomized study of OCTR and ECTR and found that endoscopic surgery was associated with less postoperative pain, but because of the small size of the benefit, they questioned the cost-effectiveness of this improvement. In addition, they found that the median length of work absence after surgery was 28 days in both groups. However, Saw and colleagues24 found a statistically significant difference between the 2 treatment groups, with the endoscopic group returning to work, on average, 8 days sooner than the open group. Therefore, these investigators recommended that ECTR should be considered in the employed as a cost-effective procedure, but that these cost savings may not be found in the general population. Larsen and colleagues25 compared the results of CTR using classic incision, short incision, or endoscopic technique. They found a significantly shorter sick leave and faster rehabilitation in the endoscopic group. However, they found no significant differences in pain, paresthesia, range of motion, pillar pain, and grip strength after 24 weeks of follow-up. Kang and colleagues26 found similar improvements in patient-reported outcome after endoscopic and open techniques at 3 months postoperatively, however, most of the patients preferred the endoscopic technique. Trumble and colleagues27 found that during the first 3 months after surgery, the patients treated with ECTR had better CTS symptom severity scores, better CTS functional status scores, and better subjective satisfaction scores compared with OCTR. During the first 3 months after surgery, these patients also had significantly greater grip strength, pinch strength, and hand dexterity. The open technique also resulted in greater scar tenderness during the first 3 months after surgery as well as a longer time until the patients could return to work. Vasiliadis and colleagues28 found that ECTR provides a faster recovery for the first 2 weeks, with faster relief of pain and faster improvement in functional abilities. Paresthesia and numbness subside in an identical manner with the 2 techniques. At 1 year postoperatively, both open and endoscopic techniques seem to be equivalently efficient. Macdermid and colleagues29 found that grip strength and pain were significantly better at 1 and 6 weeks in the endoscopic group, although differences dissipated by 12 weeks and there were no other differences in outcome. Aslani and colleagues30
compared ECTR with mini-incision techniques, and found better early satisfaction rates with endoscopic technique compared with open incision, but no difference was seen between the 2 groups after 4 months. As stated in a recent Cochrane review,31 “current evidence from randomized controlled trials showed that ECTR does not offer better relief from symptoms in the short- or long-term compared to OCTR, although ECTR seems to enable patients to return to their work or daily activities sooner.” However, return to work is a complex variable, and for the group of patients with workers’ compensation, patient selection is an important component to a fast rehabilitation.32 Several patient factors have been associated with work absence of more than 21 days: preoperative sick leave, blaming oneself for the hand problem, and a reduced preoperative nerve conduction of the motor branch of the median nerve to the thenar.33 Also, other factors may help explain the large variance in the results of sick leave after CTR between studies from different countries: reimbursement systems, social factors, culture, demographic, economic, and workplace. Whatever the health system, reduced sick leave after ECTR compared with OCTR has the potential of improving the costeffectiveness of CTR.
SUMMARY ECTR is an elegant minimally invasive operative treatment of CTS, providing a rapid rehabilitation without increasing the risk of complications. However, there is a significant learning curve and the cost of the operation is significantly higher than with conventional open technique. However, the faster rehabilitation and the probability of reducing sick leave may lead to ECTR being overall more cost-effective than open CTR.
REFERENCES 1. Cannon BW, Love JG. Tardy median palsy: median neuritis. Median thenar neuritis amenable to surgery. Surgery 1946;20:210–6. 2. Okutsu I. How I developed the world’s first evidencebased endoscopic management of carpal tunnel syndrome. Hand Surg 2010;15(3):149–55. 3. Chow JC, Hantes ME. Endoscopic carpal tunnel release: thirteen years’ experience with the Chow technique. J Hand Surg Am 2002;27(6):1011–8. 4. Agee JM, McCarroll HR Jr, Tortosa RD, et al. Endoscopic release of the carpal tunnel: a randomized prospective multicenter study. J Hand Surg Am 1992;17(6):987–95.
Endoscopic Carpal Tunnel Release 5. Chin SH, Tom LK, Thomson JG. Does the severity of bilateral carpal tunnel syndrome influence the timing of staged bilateral release? Ann Plast Surg 2011; 67(1):30–3. 6. Fehringer EV, Tiedeman JJ, Dobler K, et al. Bilateral endoscopic carpal tunnel releases: simultaneous versus staged operative intervention. Arthroscopy 2002;18(3):316–21. 7. Jones NF, Ahn HC, Eo S. Revision surgery for persistent and recurrent carpal tunnel syndrome and for failed carpal tunnel release. Plast Reconstr Surg 2012;129(3):683–92. 8. Luria S, Waitayawinyu T, Trumble TE. Endoscopic revision of carpal tunnel release. Plast Reconstr Surg 2008;121(6):2029–34 [discussion: 2035–6]. 9. Sørensen AM, Dalsgaard J, Hansen TB. Local anaesthesia versus intravenous regional anaesthesia in endoscopic carpal tunnel release: a randomized controlled trial. J Hand Surg Eur Vol 2013;38(5):481–4. 10. Nabhan A, Steudel WI, Dedeman L, et al. Subcutaneous local anesthesia versus intravenous regional anesthesia for endoscopic carpal tunnel release: a randomized controlled trial. J Neurosurg 2011;114(1):240–4. 11. Hansen TB, Kirkeby L, Fisker H, et al. Randomised controlled study of two different techniques of skin suture in endoscopic release of carpal tunnel. Scand J Plast Reconstr Surg Hand Surg 2009;43(6):335–8. 12. Beck JD, Deegan JH, Rhoades D, et al. Results of endoscopic carpal tunnel release relative to surgeon experience with the Agee technique. J Hand Surg Am 2011;36(1):61–4. 13. Okutsu I, Hamanaka I, Yoshida A. Pre- and postoperative Guyon’s canal pressure change in endoscopic carpal tunnel release: correlation with transient postoperative Guyon’s canal syndrome. J Hand Surg Eur Vol 2009;34(2):208–11. 14. Hankins CL, Brown MG, Lopez RA, et al. A 12-year experience using the Brown two-portal endoscopic procedure of transverse carpal ligament release in 14,722 patients: defining a new paradigm in the treatment of carpal tunnel syndrome. Plast Reconstr Surg 2007;120(7):1911–21. 15. Pajardi G, Pegoli L, Pivato G, et al. Endoscopic carpal tunnel release: our experience with 12,702 cases. Hand Surg 2008;13(1):21–6. 16. Beris AE, Lykissas MG, Kontogeorgakos VA, et al. Anatomic variations of the median nerve in carpal tunnel release. Clin Anat 2008;21(6):514–8. 17. Uchiyama S, Nakamura K, Itsubo T, et al. Technical difficulties and their prediction in 2-portal endoscopic carpal tunnel release for idiopathic carpal tunnel syndrome. Arthroscopy 2013;29(5): 860–9. 18. Yoshida A, Okutsu I, Hamanaka I. Comparison of clinical results between elderly and younger patients following endoscopic carpal tunnel release surgery
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for idiopathic carpal tunnel syndrome. Hand Surg 2013;18(1):59–61. Nagaoka M, Nagao S, Matsuzaki H. Endoscopic carpal tunnel release in the elderly. Minim Invasive Neurosurg 2006;49(4):216–9. Hansen TB, Larsen K. Age is an important predictor of short-term outcome in endoscopic carpal tunnel release. J Hand Surg Eur Vol 2009;34(5):660–4. Rotman MB, Enkvetchakul BV, Megerian JT, et al. Time course and predictors of median nerve conduction after carpal tunnel release. J Hand Surg Am 2004;29(3):367–72. Benson LS, Bare AA, Nagle DJ, et al. Complications of endoscopic and open carpal tunnel release. Arthroscopy 2006;22(9):919–24, 924.e1–2. Atroshi I, Larsson GU, Ornstein E, et al. Outcomes of endoscopic surgery compared with open surgery for carpal tunnel syndrome among employed patients: randomised controlled trial. BMJ 2006;332(7556):1473. Saw NL, Jones S, Shepstone L, et al. Early outcome and cost-effectiveness of endoscopic versus open carpal tunnel release: a randomized prospective trial. J Hand Surg Br 2003;28(5):444–9. Larsen MB, Sørensen AI, Crone KL, et al. Carpal tunnel release: a randomized comparison of three surgical methods. J Hand Surg Eur Vol 2013;38(6): 646–50. Kang HJ, Koh IH, Lee TJ, et al. Endoscopic carpal tunnel release is preferred over mini-open despite similar outcome: a randomized trial. Clin Orthop Relat Res 2013;471(5):1548–54. Trumble TE, Diao E, Abrams RA, et al. Single-portal endoscopic carpal tunnel release compared with open release: a prospective, randomized trial. J Bone Joint Surg Am 2002;84(7):1107–15. Vasiliadis HS, Xenakis TA, Mitsionis G, et al. Endoscopic versus open carpal tunnel release. Arthroscopy 2010;26(1):26–33. Macdermid JC, Richards RS, Roth JH, et al. Endoscopic versus open carpal tunnel release: a randomized trial. J Hand Surg Am 2003;28(3):475–80. Aslani HR, Alizadeh K, Eajazi A, et al. Comparison of carpal tunnel release with three different techniques. Clin Neurol Neurosurg 2012;114(7):965–8. Scholten RJ, Mink van der Molen A, Uitdehaag BMJ, et al. Surgical treatment options for carpal tunnel syndrome. Cochrane Database Syst Rev 2007;(4):CD003905. Duncan SF, Calandruccio JH, Merritt MV, et al. A comparison of workers’ compensation patients and nonworkers’ compensation patients undergoing endoscopic carpal tunnel release. Hand Surg 2010; 15(2):75–80. Hansen TB, Dalsgaard J, Meldgaard A, et al. A prospective study of prognostic factors for duration of sick leave after endoscopic carpal tunnel release. BMC Musculoskelet Disord 2009;10:144.
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KEY POINTS Minimal invasive surgery Effective local anesthetic surgery Reduces rehabilitation time No difference compared with open surgery after 3 months Operation costs higher than with open surgery May be more cost-effective than open surgery because of faster rehabilitation
INTRODUCTION Nature of the Problem Carpal tunnel syndrome (CTS) is a common compression neuropathy arising from increased pressure in the carpal tunnel. Wrist fracture, trauma, and vibration tools may lead to CTS, but in most patients the condition is idiopathic. If conservative treatment fails, a procedure to release the carpal tunnel is normally indicated. During a carpal tunnel release (CTR), the surgeon divides the flexor tendon retinaculum, decompressing the pressure within the carpal tunnel, a technique introduced more than 60 years ago.1 In the conventional open CTR (OCTR), the surgeon dissects directly down to the flexor tendon retinaculum through a skin incision extending from the wrist creases to the middle of the palm. The retinaculum is then split using a scalpel or scissors, resulting in decompression of the carpal tunnel. This technique necessitates an incision in the palm, which can be painful and limit recovery.
The introduction of arthroscopy for joint surgery generated the idea that arthroscopic technology could be used to treat CTS with minimal subcutaneous dissection. This idea led to the development of the endoscopic CTR (ECTR),2 which divides the retinaculum through small portals without dissecting in the subcutaneous space above the retinaculum. Two different techniques were introduced: the 2-portal system by Chow and Hantes3 and 1-portal systems by Okutsu2 and by Agee and colleagues.4 Since the initial advent, other techniques and devices have been developed, but all are variations of the original systems.
INDICATIONS/CONTRAINDICATIONS Before any operative procedure, the first step is to ensure that the diagnosis of CTS is correct (Table 1). A history and physical examination often confirm the diagnosis, and the use of preoperative nerve conduction studies (NCSs) may reduce the risk of misdiagnosing symptoms
Disclosure: This work did not receive financial support. a Section of Hand Surgery, Department of Orthopaedics, Regional Hospital Holstebro, Laegaardvej 12, Holstebro DK-7500, Denmark; b Department of Clinical Medicine, Aarhus University, Brendstrupga˚rdvej 100, 8200 Aarhus N, Aarhus C DK-8000, Denmark * Corresponding author. Department of Clinical Medicine, Aarhus University, Brendstrupga˚rdvej 100, 8200 Aarhus N, Aarhus C DK-8000, Denmark. E-mail address: [email protected] Hand Clin 30 (2014) 47–53 http://dx.doi.org/10.1016/j.hcl.2013.08.018 0749-0712/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
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Table 1 Indications/contraindications Primary Indication Idiopathic CTS
a
Relative Contraindicationa CTS secondary to trauma/ fracture CTS associated with inflammatory disease Recurrent CTS Severe obesity Anticoagulated
Consider OCTR instead.
related to other diseases, such as cervical nerve compression. Most patients are candidates for ECTR because idiopathic CTS can be safely treated with this technique. ECTR decreases the acute morbidity after CTR, and thus, some have advocated performing simultaneous ECTR in patients with bilateral disease,5 depending on the severity of the symptoms. Fehringer and colleagues6 found a decrease in the time to return to work in the simultaneous group compared with the staged group, and the simultaneous group also required fewer physician visits. Overall, patient satisfaction was equal, and the use of simultaneous surgery seems to be of economic benefit to both the patient and the hospital, reducing the cost of operation and sick leave. There are several instances in which ECTR should be approached with caution. The first group is those patients with CTS secondary to inflammatory diseases, such as rheumatoid arthritis. These patients may have synovial adhesions and hypertrophy, which can interfere with the introduction of the endoscopic device and impair the visibility in the carpal tunnel. Also, ECTR should be considered carefully in patients with a history of wrist fractures, because their previous trauma may have resulted in scarring and changes in the bony architecture of the carpal tunnel. For these patients, preoperative radiographic examination with carpal tunnel view may identify posttraumatic spaceoccupying changes. There has also been concern about ECTR in patients who have had a previous CTR. It is possible to perform ECTR as a revision surgery for recurrent CTS.7–9 The most common cause of recurrence is incomplete division of the retinaculum, and this may be treated with ECTR. However, the surgeon should always consider that the cause of the failure of the previous surgery might have been a compressive lesion, such as a lipoma, an osteophyte, or an arteria mediana. These anatomic variants may not be found during an endoscopic procedure, and if
they are suspected, the conventional open technique should be chosen. Also, fibrous scarring may cause compression and recurrence of CTS and should not be treated with ECTR. So, ECTR should be used with caution in recurrent cases and reserved for cases in which the patient had relief after the first surgery but had recurrence after several months. In general, the surgeon should use an open technique if any doubt exists regarding the cause of the recurrence. ECTR should be used with care in the severely obese patient, because a large palmar fat pad may protrude into the carpal tunnel, impairing vision during the endoscopic division of the retinaculum. In addition, in the obese patient, the tourniquet may fail, resulting in a need to convert to OCTR. Another group to approach with caution is patients taking anticoagulants. OCTR should be considered for these patients, because hemostasis is easier with this technique.
SURGICAL TECHNIQUE/PROCEDURE Preparation and Patient Positioning The patient is placed with the arm abducted on the operation table. The surgeon is positioned so that they can use the dominant hand for maneuvering the endoscope. Several anesthetic techniques have been described. Most commonly, the procedure is performed using local infiltration analgesia (LA) or in a regional block. General anesthesia is used only in patients who are unable to tolerate LA or block. LA is well tolerated, easy to manage, and has been proved to be more effective than a regional block, reducing costs and with less postoperative pain.8,10 We use the LA technique, which is simple and well tolerated. Ropivacaine 7.5 mg/mL or an equivalent local anesthetic may be used. The infiltration is performed with 4 mL administered in the proximal direction under the subcutaneous fascia of the forearm, 2 mL subcutaneously transversely in the distal wrist crease, and 4 mL subcutaneously in the palm (Fig. 1) along the crease between the thenar and the hypothenar. The tourniquet is then inflated to 80 mm Hg greater than systolic blood pressure 10 minutes after the administration of the local anesthetic and immediately before the skin incision. Good visibility during the endoscopic procedure is critical to reduce the risk of complications. Using LA with epinephrine reduces the bleeding only in the skin and not in the carpal tunnel. So a tourniquet should always be used, because bleeding inevitably impairs the vision during the procedure and leads to a highly increased risk of nerve damage.
Endoscopic Carpal Tunnel Release
Fig. 1. Infiltrating with local anesthetics.
Fig. 3. Preparing for insertion of the ECTR device.
Step 3
SURGICAL APPROACH Because we have only a limited experience with the 2-portal technique, the following description of the operative technique is based on the Agee (Microaire, Charlottesville, VA, USA) 1-portal technique. However, apart from the difference in number of portals, the main features of the procedures are the same.
Step 1 In the 1-portal technique, the incision is a transverse incision at one of the wrist creases (Fig. 2). A distal hinged fascia flap is prepared, followed by clearing synovial adhesions using a dissector. This strategy allows development of a portal down to the level of the median nerve (Fig. 3).
The knife is placed so that it rests upwards onto the retinaculum oriented along the axis of the ring finger. The endoscopic knife is introduced, and the distal border of the retinaculum localized. The distal border can be visualized by a change in color and is normally well defined. If there are any problems with the visibility and the retinaculum is difficult to define, then convert to an open procedure (“if in doubt get out”).
Step 4 Once the retinaculum is defined, the knife blade is engaged and the retinaculum is divided in distalproximal direction. While drawing the knife proximally (toward the surgeon), the focus is keeping the knife in intimate contact with the retinaculum; this prevents nerve or tendon interposition (Fig. 4).
Step 2 After the soft tissue is freed, the dilators are inserted. The dilators are inserted to ensure free mobility of the contents of the carpal tunnel, so that it is possible to freely move the knife above the tendons and nerve.
Fig. 2. Incision in the wrist crease.
Fig. 4. The view through the ECTR device showing the knife in intimate contact with the retinaculum.
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Hansen & Majeed Step 5 Next, you need to ensure a complete release. To assist with this goal, we have made a special instrument by bending a hook usually used for knee arthroscopy. We use this instrument for testing the tension of the retinaculum and retracting the fad-pad (Figs. 5 and 6). This maneuver reduces the risk of incomplete division of the retinaculum, which may lead to recurrence of the CTS. This maneuver also helps in assessing the distal border of the retinaculum by looking for the distal holdfast fibers of the flexor retinaculum described by Okutsu.2 These fibers tether the cut edges of the retinaculum so that it does not move freely and hang down after release. The presence of these fibers indicates that an incomplete division of the retinaculum should be suspected. In our experience, these fibers are easily assessed using the hook to test for tension and incomplete division. After dividing the retinaculum, it is important also to divide the proximal fascia edge at the portal, especially if the portal is placed at the distal wrist crease.
Step 6 The tourniquet may be deflated before the skin is sutured with interrupted nylon sutures or a continuous resorbable intracutaneous suture. After suturing the wound, additional Steri-Strips may be used. The use of intracutaneous suture may reduce pain in the first 24 hours compared with interrupted nylon sutures, but the difference is only small and the cosmetic appearance of the scar is equal after 3 months.11
POSTOPERATIVE CARE The hand should be immobilized in a light compressing boxer bandage (Fig. 7) for 24 to 48 hours to avoid bleeding in the carpal tunnel. After removal of the large bandage, the patient needs only a Band-Aid until the wound has healed after 10 to 12 days.
Fig. 5. The hook that may be used for retraction of a protruding fat pad and for testing the tension after dividing the retinaculum.
Fig. 6. The hook inserted in the carpal tunnel.
COMPLICATIONS AND MANAGEMENT There is a significant learning curve in ECTR, but Beck and colleagues12 found that the rates of conversion significantly diminished with increased surgeon and anesthesia experience. During this learning curve, patients may be at a higher risk of conversion to OCTR, but there is no increased morbidity. Because LA may increase the risk of impaired visibility during the procedure, it may be advised to use a regional block initially until the surgeon feels comfortable with the endoscopic technique. The complication most feared with ECTR is injury to a nerve. Most commonly, these injuries are a transient neuropraxia. For example, decompression of the carpal tunnel using ECTR may result in changes in pressure in the Guyon canal, leading
Fig. 7. Immobilization in a light compressing boxer bandage for 24 to 48 hours to avoid bleeding in the carpal tunnel.
Endoscopic Carpal Tunnel Release to Guyon canal syndrome, but these symptoms are normally brief.13 Transitory median nerve sensory disturbances also may occur after ECTR, probably because of compression, stretching, or manipulation of the median nerve during the operation. Although rare, the most serious complication is permanent nerve injury caused by cutting into the nerve.14,15 To avoid this complication, surgeons must be aware that neural variations arising from the ulnar aspect of the median nerve are common and these could put the nerve at risk for iatrogenic injury during either endoscopic or open release.16 To minimize risk of complications, the surgeon must be willing to convert to an OCTR if the situation is suboptimal. In particular, the risk for nerve injury is amplified if the visibility during the procedure is impaired. Thus, if bleeding is limiting the visibility during an ECTR, the surgeon should seriously consider converting to an open procedure. Another criterion for safe release of the flexor retinaculum using ECTR is that the contents of the carpal tunnel must be freely moveable by the endoscope. If the surgeon encounters a mechanical block or significant resistance during the introduction of the endoscope (which may be caused by synovial adhesions or an abnormality within the carpal tunnel), conversion to an open procedure is highly recommended. The surgeon may also encounter difficulties when introducing the endoscope in a small wrist. Uchiyama and colleagues17 found that tight access was experienced more frequently in younger patients and those with a small cross-sectional area at the hook-of-hamate level. These investigators found that ECTR was easily performed in older female patients. Although the younger patients were more challenging, this study did not identify a group of patients in whom ECTR should be avoided, and the conclusion was that no group should be excluded based on solely age, body size, or gender. As with any surgical procedure, postoperative bleeding may occur after ECTR, resulting in swelling of the hand and an increased risk of infection. To limit this risk, a light compressive bandage is recommended during the first 24 hours. Also, as mentioned earlier, for patients on anticoagulants, OCTR should be considered. Postoperative infection and reflex sympathetic dystrophy syndrome are rare complications14,15 and not specific to ECTR compared with hand surgery in general. Efficacy of ECTR to relieve carpal tunnel symptoms varies depending on the age of the patient, the severity of the CTS, and the duration of the nerve compression.18–20 However, complete lack of relief of the preoperative symptoms suggests
that the diagnosis may have been wrong or that there has been an incomplete release of the retinaculum. One concern with ECTR is an increase in risk of inadequate release because of limited visibility of the retinaculum when compared with the direct approach of OCTR. This risk is reduced with increasing experience with ECTR and by using our modified hook to help inspect for any residual compressive bands (see step 5). Repeat NCSs are helpful in evaluating patients who have not improved after surgery. Rotman and colleagues21 found that postsurgical changes in the distal motor latency of the median nerve were highly dependent on the prerelease latency. This sensitivity and specificity of an NCS can aid in determining the level of improvement in median nerve function after ECTR. An NCS performed 3 months after the operation should show some improvement compared with preoperative values. If not, the possibility of an incomplete division of the retinaculum should be suspected and reoperation considered. Overall, the literature has found ECTR to be a safe procedure. Hankins and colleagues’14 reported on a large series of patient and had only 1 nerve injury in 14,722 patients and a conversion rate to open procedure of 0.07%. In another series of 12,702 patients, Pajardi and colleagues15 had 6 nerve injuries (3 partial), 12 recurrences, and a conversion to open procedure of 0.46%. Benson and colleagues22 performed a meta-analysis of 80 publications, including 22,327 cases of ECTR and 5669 cases of OCTR release, and found that the proportion of complications was very low for CTR, performed either endoscopic or open. Thus, selection of CTR technique should be based on surgeon and patient preference.
POSTOPERATIVE CARE This section outlines our postoperative instructions after ECTR. To avoid wound infection, patients are advised to keep the wound away from dirt until the skin has healed after 10 to 14 days. Workers without hand-demanding tasks may work after removal of the compressing bandage after 24 to 48 hours. Workers with hand-demanding tasks may benefit from a sick leave of 10 to 14 days until the wound has healed. After the wound has healed, no specific restrictions are needed, and the patients are allowed to use the hand as much as pain and tenderness allow. Normally, no formal therapy is required. No routine controls are needed.
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Hansen & Majeed OUTCOMES ECTR has been extensively studied. Much of the focus has been on the impact of ECTR on postoperative recovery. In this section, several randomized controlled trials that have compared ECTR with OCTR are reviewed. Atroshi and colleagues23 performed a randomized study of OCTR and ECTR and found that endoscopic surgery was associated with less postoperative pain, but because of the small size of the benefit, they questioned the cost-effectiveness of this improvement. In addition, they found that the median length of work absence after surgery was 28 days in both groups. However, Saw and colleagues24 found a statistically significant difference between the 2 treatment groups, with the endoscopic group returning to work, on average, 8 days sooner than the open group. Therefore, these investigators recommended that ECTR should be considered in the employed as a cost-effective procedure, but that these cost savings may not be found in the general population. Larsen and colleagues25 compared the results of CTR using classic incision, short incision, or endoscopic technique. They found a significantly shorter sick leave and faster rehabilitation in the endoscopic group. However, they found no significant differences in pain, paresthesia, range of motion, pillar pain, and grip strength after 24 weeks of follow-up. Kang and colleagues26 found similar improvements in patient-reported outcome after endoscopic and open techniques at 3 months postoperatively, however, most of the patients preferred the endoscopic technique. Trumble and colleagues27 found that during the first 3 months after surgery, the patients treated with ECTR had better CTS symptom severity scores, better CTS functional status scores, and better subjective satisfaction scores compared with OCTR. During the first 3 months after surgery, these patients also had significantly greater grip strength, pinch strength, and hand dexterity. The open technique also resulted in greater scar tenderness during the first 3 months after surgery as well as a longer time until the patients could return to work. Vasiliadis and colleagues28 found that ECTR provides a faster recovery for the first 2 weeks, with faster relief of pain and faster improvement in functional abilities. Paresthesia and numbness subside in an identical manner with the 2 techniques. At 1 year postoperatively, both open and endoscopic techniques seem to be equivalently efficient. Macdermid and colleagues29 found that grip strength and pain were significantly better at 1 and 6 weeks in the endoscopic group, although differences dissipated by 12 weeks and there were no other differences in outcome. Aslani and colleagues30
compared ECTR with mini-incision techniques, and found better early satisfaction rates with endoscopic technique compared with open incision, but no difference was seen between the 2 groups after 4 months. As stated in a recent Cochrane review,31 “current evidence from randomized controlled trials showed that ECTR does not offer better relief from symptoms in the short- or long-term compared to OCTR, although ECTR seems to enable patients to return to their work or daily activities sooner.” However, return to work is a complex variable, and for the group of patients with workers’ compensation, patient selection is an important component to a fast rehabilitation.32 Several patient factors have been associated with work absence of more than 21 days: preoperative sick leave, blaming oneself for the hand problem, and a reduced preoperative nerve conduction of the motor branch of the median nerve to the thenar.33 Also, other factors may help explain the large variance in the results of sick leave after CTR between studies from different countries: reimbursement systems, social factors, culture, demographic, economic, and workplace. Whatever the health system, reduced sick leave after ECTR compared with OCTR has the potential of improving the costeffectiveness of CTR.
SUMMARY ECTR is an elegant minimally invasive operative treatment of CTS, providing a rapid rehabilitation without increasing the risk of complications. However, there is a significant learning curve and the cost of the operation is significantly higher than with conventional open technique. However, the faster rehabilitation and the probability of reducing sick leave may lead to ECTR being overall more cost-effective than open CTR.
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