524688 research-article2014
JHS0010.1177/1753193414524688The Journal of Hand SurgeryEcker et al.
JHS(E)
Full length article
Supraretinacular endoscopic carpal tunnel release: surgical technique with prospective case series
The Journal of Hand Surgery (European Volume) 2015, Vol. 40E(2) 193–198 © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1753193414524688 jhs.sagepub.com
J. Ecker1, N. Perera2 and J. Ebert3 Abstract Current techniques for endoscopic carpal tunnel release use an infraretinacular approach, inserting the endoscope deep to the flexor retinaculum. We present a supraretinacular endoscopic carpal tunnel release technique in which a dissecting endoscope is inserted superficial to the flexor retinaculum, which improves vision and the ability to dissect and manipulate the median nerve and tendons during surgery. The motor branch of the median nerve and connections between the median and ulnar nerve can be identified and dissected. Because the endoscope is inserted superficial to the flexor retinaculum, the median nerve is not compressed before division of the retinaculum and, as a result, we have observed no cases of the transient median nerve deficits that have been reported using infraretinacular endoscopic techniques. Level of evidence: IV. Keywords Supraretinacular endoscopic carpal tunnel release Date received: 18th April 2013; revised: 16th January 2014; accepted: 22nd January 2014
Introduction In patients with carpal tunnel syndrome (CTS) treated by carpal tunnel release (CTR), the flexor retinaculum can be released by open (OCTR) or endoscopic (ECTR) techniques. Although similar complication rates for OCTR and ECTR have been reported (Benson et al., 2006; Huisstede et al., 2010; Jimenez et al., 1998), post-operative recovery, return to work, and activities of daily living are more rapid with ECTR (Saw et al., 2003; Scholten et al., 2007; Teh et al., 2009; Trumble et al., 2002; Wong et al., 2003). This paper describes a new way to perform endoscopic release using a supraretinacular (SRECTR) approach.
recovery, before consenting to surgery and completing study documentation. All patients had signed a consent form to undertake surgery, as well as allow their clinical data to be de-identified and used for research programmes.
Surgical technique SRECTR is carried out in an ischaemic field under tourniquet control using a general anaesthetic (> 95% cases), although the procedure has been done using local anaesthetic infiltration and intravenous blocks (< 5% cases) without difficulty.
Methods A prospective study was carried out in the first 50 consecutive patients treated using this technique. There were 33 men and 17 women, with a mean age of 57 (range 27–83) years. The diagnosis of CTS was based on numbness and paraesthesia in the median nerve distribution, positive Tinel’s sign, positive modified Phalen’s test, and positive neurophysiological studies. Before surgery, all patients were counselled about the procedure, possible risks, and post-operative
1Western
Orthopaedic Clinic, SJOG Health Care, Subiaco, Australia 2Hand and Upper Limb Centre, Subiaco, Australia 3School of Sport Science, Exercise and Health, University of Western Australia, Crawley, Perth, Australia Corresponding author: Dr. Jay R. Ebert, School of Sport Science, Exercise and Health, University of Western Australia, 35 Stirling Highway, Crawley, 6009, Australia. Email: [email protected]
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Figure 1. (A) Surface anatomy demonstrating the pisiform, hook of hamate, trapezium, flexor carpi radialis (FCR) and palmaris longus (PL) tendons. (B) The line of incision made in the crease of the wrist joint.
The pisiform, hook of hamate, trapezium, tendons of flexor carpi radialis and palmaris longus, and axis between the ring and middle finger are marked on the skin with a sterile pen to define the surface anatomy of the flexor retinaculum (Figure 1A). The wrist is flexed and a 2.5 cm transverse incision line is marked in the radiocarpal wrist flexion crease (Figure 1B). The radial side of the incision line starts on the ulnar side of the flexor carpi radialis tendon and crosses the palmaris longus tendon when present. After dividing the skin the forearm fascia is incised longitudinally. The median nerve is dissected to look for anatomical variation, such as proximal bifurcation or abnormal muscles. Six-inch tenotomy scissors are inserted on the palmar surface of the flexor retinaculum. The scissor tips are angled palmarly and the blades are opened to create a space immediately palmar to the flexor retinaculum, and between the flexor retinaculum and overlying thick layer of subcutaneous fat and skin, along the axial line between the middle and ring fingers. The space created is ulnar to the superficial branch of the median nerve and should be just large enough (approximately 2 cm in diameter) to insert the small dual light source speculum (Illuminated nasal speculum, 90 mm blade; Karl Storz GmbH & Co. KG, Tuttlingen, Germany). This space should not extend beyond the distal edge of the flexor retinaculum. Excessive dissection superficial to the flexor retinaculum may result in increased palmar scarring and post-operative soft tissue induration. Under direct vision, the proximal 3–5 mm of the flexor retinaculum is initially divided making it easy to find the proximal edge of the flexor retinaculum upon endoscopic dissection. The dual light-source speculum is inserted into this space along the ring and middle finger axis, and an endoscope (HOPKINS II forward-oblique telescope 30°; Karl Storz GmbH & Co. KG) with a soft tissue dissection extension (Optical Dissector; Karl
Storz GmbH & Co. KG) is inserted within the opened speculum. To adequately manipulate and dissect the soft tissue, the endoscope is held with the index, middle, and ring fingers above and the thumb below the barrel (Figure 2). The assistant holds the speculum in alignment with the longitudinal axis between the ring and middle flingers so that the surgeon can concentrate on dissection and division of the flexor retinaculum. Metzenbaum scissors (Karl Storz GmbH & Co. KG) are used to divide the superficial palmar aponeurosis and flexor retinaculum under endoscopic vision. A range of scissors with varying handle lengths (18–28 cm) may be required so that the scissor handles can be opened without impinging on the endoscope and camera body. The scissors are inserted (Figure 3A) with one of the scissor blades positioned deep to the flexor retinaculum. Aberrant muscles often cross the midline and are in the path of division of the flexor retinaculum. These aberrant muscles are dissected carefully in layers from palmar to dorsal. If nerves are present in muscle they can be identified during the dissection process because they are surrounded by a thin layer of fat. By moving and dissecting aberrant muscles that cross the midline with closed scissor tips, nerves can be identified before dividing the flexor retinaculum. In cases where there is a distinct superficial palmar aponeurosis, this should be divided before incising the flexor retinaculum. Aberrant muscles are usually found in the plane between the superficial palmar aponeurosis. The flexor retinaculum is divided along the longitudinal axis using a series of small sequential cuts (Figure 3B). It is essential that clear vision of the scissor blade and surrounding structures is maintained to avoid damage to aberrant nerve branches and blood vessels. Manipulating the endoscope to hold the space open enables clear vision of the flexor retinaculum during division. The superficial palmar arch marks the distal extent of
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Figure 2. (A) Appropriate grip and positioning of the endoscope as it is (B) inserted into the speculum superficial to the flexor retinaculum.
Figure 3. (A) Metzenbaum scissors are inserted and (B) used to divide the flexor retinaculum (FR).
the flexor retinaculum and confirms that division is complete. Using this technique, the contents of the carpal canal can be visualized (Figure 4A). The recurrent motor branch of the median nerve can be dissected using the endoscope dissector, longhandled Sawtell clamp, and probe. The Sawtell clamp tips are used to spread and dissect. The flexor tendons and floor of the carpal canal can be examined (Figure 4B,C). Endoscopic dissection enables visualization of anatomical variations in the median nerve, recurrent motor branch of the median nerve, superficial communicating branches between the median and ulnar nerves, aberrant arteries lying palmar to the flexor retinaculum, and superficial palmar arch. Most SRECTR cases are simple and straightforward (see SRECTR video at http://jeffecker.com.au/videos). However, in order to carry out this technique safely the surgeon must be aware of anatomical variations of nerves and muscles, and be able to competently perform micro-endoscopic dissection (see aberrant
motor branch dissection video at http://jeffecker.com. au/videos). Figure 5 demonstrates a motor branch of the median nerve with a proximal origin penetrating the flexor retinaculum. At the completion of the procedure, the incision is closed with interrupted 4-0 polypropylene sutures. A bulky compressive dressing is removed 6–12 hours after surgery and a waterproof adhesive dressing is placed over the incision. Active and passive exercises are started immediately with the focus on regaining full movement of the wrist and fingers within 1–2 days. Patients are encouraged to use their hands within their range of comfort immediately after surgery. Patients can get their hands wet as long as they have an adhesive waterproof dressing on the incision line.
Clinical assessment Prospective pre- and post-operative (2 weeks, 6 weeks, 12 weeks, and 6 months) assessments were
Downloaded from jhs.sagepub.com at East Tennessee State University on June 4, 2015
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The Journal of Hand Surgery (Eur) 40(2)
Figure 4. (A) View of the median nerve, flexor retinaculum (FR), recurrent motor branch (RMB), and endoscope dissector. (B,C) Flexor pollicis longus (FPL) tendon and flexor tendons to the small and ring fingers.
Results There were no cases of increased sensory nerve deficit or nerve damage after SRECTR. Pillar pain was present in some form in all patients 2 weeks after surgery, although it was absent in all cases by 3 months. The scar was barely perceptible in all cases. A significant improvement (p < 0.05) was observed in DASH scores, as well as MIDONR scores throughout the post-operative timeline (Table 1).
Complications
Figure 5. Recurrent motor branch (RMB) of the median nerve with a proximal origin penetrating the flexor retinaculum (FR).
undertaken in the first 50 consecutive patients, using the Disabilities of the Shoulder, Arm, and Hand (DASH) questionnaire (Wong et al., 2007) and Model Instrument for Documentation of Outcome after Nerve Repair (MIDONR) (Rosén and Lundborg, 2000). Pillar pain was recorded at the post-operative time points as being ‘present’ or ‘absent’, when the patient was asked to weight bear on the palm of their operated hand with their wrist held in dorsiflexion (i.e., push down on a desk).
Statistical analyses A one-way repeated measure analysis of variance (ANOVA) was used to investigate the change in clinical scores over the assessment timeline. Statistical significance was set at p < 0.05.
There were five cases of inflammation and redness around the incision line, all of which resolved following removal of the sutures and a 5-day course of cefalexin. Patients on anticoagulants for coexistent pathology underwent SRECTR without modifying their anticoagulation regimen. Subcutaneous bruising without haematoma formation occurred in these patients, which resolved within 1–2 weeks. Of the first 50 SRECTR cases, none required conversion to OCTR. In this prospective study, we did more than 650 cases of SRECTR, of which two required conversion to OCTR. These cases have been included because they are instructive and emphasize the observation that atypical intra-muscular nerve branches are often associated with large aberrant muscles that may cross the midline, and if clear vision is not achieved during the endoscopic procedure, then conversion to OCTR is mandatory. After conversion of these two subsequent cases to OCTR, the first case demonstrated a bifid motor branch of the median nerve within the distal aberrant muscle, which would almost certainly have been damaged if the SRECTR had not been converted to an OCTR. The second case had a trans-ligamentous motor branch of the median nerve associated with a superficial
Downloaded from jhs.sagepub.com at East Tennessee State University on June 4, 2015
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Ecker et al.
Table 1. ANOVA demonstrated a significant improvement over the pre- and post-operative timeline for the DASH questionnaire and MIDONR; mean (standard deviation) shown. Outcome measure
Pre-surgery
2 weeks
6 weeks
12 weeks
6 months
p value
DASH MIDONR
29 (5) 2.6 (0.3)
36 (6) 2.7 (0.3)
22 (5) 2.7 (0.2)
19 (3) 2.8 (0.4)
11 (4) 2.9 (0.1)
0.010 0.008
communicating branch between the median and ulnar nerves.
Discussion In SRECTR, instrumentation and dissection are done in a plane superficial to the flexor retinaculum. In our view, the primary advantage of this technique over existing infraretinacular methods is the visual clarity that allows endoscopic dissection of aberrant muscles crossing the midline on the palmar surface of the flexor retinaculum and identification of aberrant nerves and vessels while dividing it. The median nerve and motor branch, communications between the median and ulnar nerves and flexor tendons can be identified and dissected. To the best of our knowledge, there is no available technique of ECTR that permits the clear view of aberrant nerves or allows the surgeon to identify, explore, and manipulate the nerves and tendons within the carpal canal. A similar endoscopic technique presenting 10 cases has been published recently, though does not document endoscopic dissection and manipulation of the median nerve, aberrant nerve branches, tendons and vessels (Ip et al., 2012). With the improved vision afforded, we feel SRECTR provides a safer alternative to existing methods of ECTR. Transient median nerve deficits have been reported using infraretinacular ECTR methods. We have not found any cases of transient neurological deficits after SRECTR. In our experience, the most likely cause of these neurological deficits is the insertion of endoscopic instruments deep to the flexor retinaculum causing pressure on the median nerve, which is avoided with SRECTR. Furthermore, identifying the median nerve at the wrist flexion crease before inserting instruments means there is no proximal ‘blind spot’ that occurs with OCTR using an incision restricted to the palm. Identifying the median nerve in this manner ensures that median nerves that bifurcate proximal to the flexor retinaculum are recognized before dividing the flexor retinaculum. Duplex median nerves also have an increased risk of iatrogenic damage during infraretinacular ECTR. There is a learning curve with SRECTR. Before using this technique it is recommended that time is
spent in the fresh frozen cadaver laboratory developing the necessary dissecting skills so that it can be undertaken safely. It is essential that surgeons performing SRECTR have clear view of the anatomy before cutting the flexor retinaculum. This is especially important in the presence of large aberrant muscles that cross the midline on the palmar surface of the flexor retinaculum, and which need to be dissected in layers. Muscles that cross the midline of the flexor retinaculum can be very large and it may not be possible to safely dissect them in layers while maintaining a good field of vision. When this occurs, conversion to an open procedure is necessary to avoid inadvertent division of aberrant nerves. In our opinion, patients presenting with CTS with a history of CTR, flexor tenosynovitis associated with a connective tissue disorder or tumours in the carpal canal should be treated by OCTR. Acknowledgements We would like to acknowledge the clinical and research work of Shannon Edwick and Dr. Jessica Scoullar, as well as the time and effort provided by the patient group.
Conflict of interests None declared.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
References Benson LS, Bare AA, Nagle DJ, Harder VS, Williams CS, Visotsky JL. Complications of endoscopic and open carpal tunnel release. Arthroscopy. 2006, 22: 919–24, 24 e1–2. Huisstede BM, Randsdorp MS, Coert JH, Glerum S, van Middelkoop M, Koes BW. Carpal tunnel syndrome. Part II: effectiveness of surgical treatments—a systematic review. Arch Phys Med Rehabil. 2010, 91: 1005–24. Ip WY, Sweed TA, Fung KK, Tipoe GL, Pun TS. A new technique of single portal endoscopic carpal tunnel release. Tech Hand Up Extrem Surg. 2012, 16: 27–9. Jimenez DF, Gibbs SR, Clapper AT. Endoscopic treatment of carpal tunnel syndrome: a critical review. J Neurosurg. 1998, 88: 817–26.
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Rosén B, Lundborg G. A model instrument for the documentation of outcome after nerve repair. J Hand Surg Am. 2000, 25: 535–43. Saw NL, Jones S, Shepstone L, Meyer M, Chapman PG, Logan AM. Early outcome and cost-effectiveness of endoscopic versus open carpal tunnel release: a randomized prospective trial. J Hand Surg Br. 2003, 28: 444–9. Scholten RJ, Mink van der Molen A, Uitdehaag BM, Bouter LM, de Vet HC. Surgical treatment options for carpal tunnel syndrome. Cochrane Database Syst Rev. 2007: CD003905. Teh K, Ng E, Choon D. Mini open carpal tunnel release using knifelight: Evaluation of the safety and effective-
ness of using a single wrist incision (cadaveric study). J Hand Surg Br. 2009, 34E: 506–10. Trumble TE, Diao E, Abrams RA, Gilbert-Anderson MM. Single-portal endoscopic carpal tunnel release compared with open release: a prospective, randomized trial. J Bone Joint Surg Am. 2002, 84-A: 1107–15. Wong JY, Fung BK, Chu MM, Chan RK. The use of Disabilities of the Arm, Shoulder, and Hand Questionnaire in rehabilitation after acute traumatic hand injuries. J Hand Ther. 2007, 20: 49–55. Wong KC, Hung LK, Ho PC, Wong JM. Carpal tunnel release. A prospective, randomised study of endoscopic versus limited-open methods. J Bone Joint Surg Br. 2003, 85: 863–8.
Downloaded from jhs.sagepub.com at East Tennessee State University on June 4, 2015
JHS0010.1177/1753193414524688The Journal of Hand SurgeryEcker et al.
JHS(E)
Full length article
Supraretinacular endoscopic carpal tunnel release: surgical technique with prospective case series
The Journal of Hand Surgery (European Volume) 2015, Vol. 40E(2) 193–198 © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1753193414524688 jhs.sagepub.com
J. Ecker1, N. Perera2 and J. Ebert3 Abstract Current techniques for endoscopic carpal tunnel release use an infraretinacular approach, inserting the endoscope deep to the flexor retinaculum. We present a supraretinacular endoscopic carpal tunnel release technique in which a dissecting endoscope is inserted superficial to the flexor retinaculum, which improves vision and the ability to dissect and manipulate the median nerve and tendons during surgery. The motor branch of the median nerve and connections between the median and ulnar nerve can be identified and dissected. Because the endoscope is inserted superficial to the flexor retinaculum, the median nerve is not compressed before division of the retinaculum and, as a result, we have observed no cases of the transient median nerve deficits that have been reported using infraretinacular endoscopic techniques. Level of evidence: IV. Keywords Supraretinacular endoscopic carpal tunnel release Date received: 18th April 2013; revised: 16th January 2014; accepted: 22nd January 2014
Introduction In patients with carpal tunnel syndrome (CTS) treated by carpal tunnel release (CTR), the flexor retinaculum can be released by open (OCTR) or endoscopic (ECTR) techniques. Although similar complication rates for OCTR and ECTR have been reported (Benson et al., 2006; Huisstede et al., 2010; Jimenez et al., 1998), post-operative recovery, return to work, and activities of daily living are more rapid with ECTR (Saw et al., 2003; Scholten et al., 2007; Teh et al., 2009; Trumble et al., 2002; Wong et al., 2003). This paper describes a new way to perform endoscopic release using a supraretinacular (SRECTR) approach.
recovery, before consenting to surgery and completing study documentation. All patients had signed a consent form to undertake surgery, as well as allow their clinical data to be de-identified and used for research programmes.
Surgical technique SRECTR is carried out in an ischaemic field under tourniquet control using a general anaesthetic (> 95% cases), although the procedure has been done using local anaesthetic infiltration and intravenous blocks (< 5% cases) without difficulty.
Methods A prospective study was carried out in the first 50 consecutive patients treated using this technique. There were 33 men and 17 women, with a mean age of 57 (range 27–83) years. The diagnosis of CTS was based on numbness and paraesthesia in the median nerve distribution, positive Tinel’s sign, positive modified Phalen’s test, and positive neurophysiological studies. Before surgery, all patients were counselled about the procedure, possible risks, and post-operative
1Western
Orthopaedic Clinic, SJOG Health Care, Subiaco, Australia 2Hand and Upper Limb Centre, Subiaco, Australia 3School of Sport Science, Exercise and Health, University of Western Australia, Crawley, Perth, Australia Corresponding author: Dr. Jay R. Ebert, School of Sport Science, Exercise and Health, University of Western Australia, 35 Stirling Highway, Crawley, 6009, Australia. Email: [email protected]
Downloaded from jhs.sagepub.com at East Tennessee State University on June 4, 2015
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The Journal of Hand Surgery (Eur) 40(2)
Figure 1. (A) Surface anatomy demonstrating the pisiform, hook of hamate, trapezium, flexor carpi radialis (FCR) and palmaris longus (PL) tendons. (B) The line of incision made in the crease of the wrist joint.
The pisiform, hook of hamate, trapezium, tendons of flexor carpi radialis and palmaris longus, and axis between the ring and middle finger are marked on the skin with a sterile pen to define the surface anatomy of the flexor retinaculum (Figure 1A). The wrist is flexed and a 2.5 cm transverse incision line is marked in the radiocarpal wrist flexion crease (Figure 1B). The radial side of the incision line starts on the ulnar side of the flexor carpi radialis tendon and crosses the palmaris longus tendon when present. After dividing the skin the forearm fascia is incised longitudinally. The median nerve is dissected to look for anatomical variation, such as proximal bifurcation or abnormal muscles. Six-inch tenotomy scissors are inserted on the palmar surface of the flexor retinaculum. The scissor tips are angled palmarly and the blades are opened to create a space immediately palmar to the flexor retinaculum, and between the flexor retinaculum and overlying thick layer of subcutaneous fat and skin, along the axial line between the middle and ring fingers. The space created is ulnar to the superficial branch of the median nerve and should be just large enough (approximately 2 cm in diameter) to insert the small dual light source speculum (Illuminated nasal speculum, 90 mm blade; Karl Storz GmbH & Co. KG, Tuttlingen, Germany). This space should not extend beyond the distal edge of the flexor retinaculum. Excessive dissection superficial to the flexor retinaculum may result in increased palmar scarring and post-operative soft tissue induration. Under direct vision, the proximal 3–5 mm of the flexor retinaculum is initially divided making it easy to find the proximal edge of the flexor retinaculum upon endoscopic dissection. The dual light-source speculum is inserted into this space along the ring and middle finger axis, and an endoscope (HOPKINS II forward-oblique telescope 30°; Karl Storz GmbH & Co. KG) with a soft tissue dissection extension (Optical Dissector; Karl
Storz GmbH & Co. KG) is inserted within the opened speculum. To adequately manipulate and dissect the soft tissue, the endoscope is held with the index, middle, and ring fingers above and the thumb below the barrel (Figure 2). The assistant holds the speculum in alignment with the longitudinal axis between the ring and middle flingers so that the surgeon can concentrate on dissection and division of the flexor retinaculum. Metzenbaum scissors (Karl Storz GmbH & Co. KG) are used to divide the superficial palmar aponeurosis and flexor retinaculum under endoscopic vision. A range of scissors with varying handle lengths (18–28 cm) may be required so that the scissor handles can be opened without impinging on the endoscope and camera body. The scissors are inserted (Figure 3A) with one of the scissor blades positioned deep to the flexor retinaculum. Aberrant muscles often cross the midline and are in the path of division of the flexor retinaculum. These aberrant muscles are dissected carefully in layers from palmar to dorsal. If nerves are present in muscle they can be identified during the dissection process because they are surrounded by a thin layer of fat. By moving and dissecting aberrant muscles that cross the midline with closed scissor tips, nerves can be identified before dividing the flexor retinaculum. In cases where there is a distinct superficial palmar aponeurosis, this should be divided before incising the flexor retinaculum. Aberrant muscles are usually found in the plane between the superficial palmar aponeurosis. The flexor retinaculum is divided along the longitudinal axis using a series of small sequential cuts (Figure 3B). It is essential that clear vision of the scissor blade and surrounding structures is maintained to avoid damage to aberrant nerve branches and blood vessels. Manipulating the endoscope to hold the space open enables clear vision of the flexor retinaculum during division. The superficial palmar arch marks the distal extent of
Downloaded from jhs.sagepub.com at East Tennessee State University on June 4, 2015
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Figure 2. (A) Appropriate grip and positioning of the endoscope as it is (B) inserted into the speculum superficial to the flexor retinaculum.
Figure 3. (A) Metzenbaum scissors are inserted and (B) used to divide the flexor retinaculum (FR).
the flexor retinaculum and confirms that division is complete. Using this technique, the contents of the carpal canal can be visualized (Figure 4A). The recurrent motor branch of the median nerve can be dissected using the endoscope dissector, longhandled Sawtell clamp, and probe. The Sawtell clamp tips are used to spread and dissect. The flexor tendons and floor of the carpal canal can be examined (Figure 4B,C). Endoscopic dissection enables visualization of anatomical variations in the median nerve, recurrent motor branch of the median nerve, superficial communicating branches between the median and ulnar nerves, aberrant arteries lying palmar to the flexor retinaculum, and superficial palmar arch. Most SRECTR cases are simple and straightforward (see SRECTR video at http://jeffecker.com.au/videos). However, in order to carry out this technique safely the surgeon must be aware of anatomical variations of nerves and muscles, and be able to competently perform micro-endoscopic dissection (see aberrant
motor branch dissection video at http://jeffecker.com. au/videos). Figure 5 demonstrates a motor branch of the median nerve with a proximal origin penetrating the flexor retinaculum. At the completion of the procedure, the incision is closed with interrupted 4-0 polypropylene sutures. A bulky compressive dressing is removed 6–12 hours after surgery and a waterproof adhesive dressing is placed over the incision. Active and passive exercises are started immediately with the focus on regaining full movement of the wrist and fingers within 1–2 days. Patients are encouraged to use their hands within their range of comfort immediately after surgery. Patients can get their hands wet as long as they have an adhesive waterproof dressing on the incision line.
Clinical assessment Prospective pre- and post-operative (2 weeks, 6 weeks, 12 weeks, and 6 months) assessments were
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The Journal of Hand Surgery (Eur) 40(2)
Figure 4. (A) View of the median nerve, flexor retinaculum (FR), recurrent motor branch (RMB), and endoscope dissector. (B,C) Flexor pollicis longus (FPL) tendon and flexor tendons to the small and ring fingers.
Results There were no cases of increased sensory nerve deficit or nerve damage after SRECTR. Pillar pain was present in some form in all patients 2 weeks after surgery, although it was absent in all cases by 3 months. The scar was barely perceptible in all cases. A significant improvement (p < 0.05) was observed in DASH scores, as well as MIDONR scores throughout the post-operative timeline (Table 1).
Complications
Figure 5. Recurrent motor branch (RMB) of the median nerve with a proximal origin penetrating the flexor retinaculum (FR).
undertaken in the first 50 consecutive patients, using the Disabilities of the Shoulder, Arm, and Hand (DASH) questionnaire (Wong et al., 2007) and Model Instrument for Documentation of Outcome after Nerve Repair (MIDONR) (Rosén and Lundborg, 2000). Pillar pain was recorded at the post-operative time points as being ‘present’ or ‘absent’, when the patient was asked to weight bear on the palm of their operated hand with their wrist held in dorsiflexion (i.e., push down on a desk).
Statistical analyses A one-way repeated measure analysis of variance (ANOVA) was used to investigate the change in clinical scores over the assessment timeline. Statistical significance was set at p < 0.05.
There were five cases of inflammation and redness around the incision line, all of which resolved following removal of the sutures and a 5-day course of cefalexin. Patients on anticoagulants for coexistent pathology underwent SRECTR without modifying their anticoagulation regimen. Subcutaneous bruising without haematoma formation occurred in these patients, which resolved within 1–2 weeks. Of the first 50 SRECTR cases, none required conversion to OCTR. In this prospective study, we did more than 650 cases of SRECTR, of which two required conversion to OCTR. These cases have been included because they are instructive and emphasize the observation that atypical intra-muscular nerve branches are often associated with large aberrant muscles that may cross the midline, and if clear vision is not achieved during the endoscopic procedure, then conversion to OCTR is mandatory. After conversion of these two subsequent cases to OCTR, the first case demonstrated a bifid motor branch of the median nerve within the distal aberrant muscle, which would almost certainly have been damaged if the SRECTR had not been converted to an OCTR. The second case had a trans-ligamentous motor branch of the median nerve associated with a superficial
Downloaded from jhs.sagepub.com at East Tennessee State University on June 4, 2015
197
Ecker et al.
Table 1. ANOVA demonstrated a significant improvement over the pre- and post-operative timeline for the DASH questionnaire and MIDONR; mean (standard deviation) shown. Outcome measure
Pre-surgery
2 weeks
6 weeks
12 weeks
6 months
p value
DASH MIDONR
29 (5) 2.6 (0.3)
36 (6) 2.7 (0.3)
22 (5) 2.7 (0.2)
19 (3) 2.8 (0.4)
11 (4) 2.9 (0.1)
0.010 0.008
communicating branch between the median and ulnar nerves.
Discussion In SRECTR, instrumentation and dissection are done in a plane superficial to the flexor retinaculum. In our view, the primary advantage of this technique over existing infraretinacular methods is the visual clarity that allows endoscopic dissection of aberrant muscles crossing the midline on the palmar surface of the flexor retinaculum and identification of aberrant nerves and vessels while dividing it. The median nerve and motor branch, communications between the median and ulnar nerves and flexor tendons can be identified and dissected. To the best of our knowledge, there is no available technique of ECTR that permits the clear view of aberrant nerves or allows the surgeon to identify, explore, and manipulate the nerves and tendons within the carpal canal. A similar endoscopic technique presenting 10 cases has been published recently, though does not document endoscopic dissection and manipulation of the median nerve, aberrant nerve branches, tendons and vessels (Ip et al., 2012). With the improved vision afforded, we feel SRECTR provides a safer alternative to existing methods of ECTR. Transient median nerve deficits have been reported using infraretinacular ECTR methods. We have not found any cases of transient neurological deficits after SRECTR. In our experience, the most likely cause of these neurological deficits is the insertion of endoscopic instruments deep to the flexor retinaculum causing pressure on the median nerve, which is avoided with SRECTR. Furthermore, identifying the median nerve at the wrist flexion crease before inserting instruments means there is no proximal ‘blind spot’ that occurs with OCTR using an incision restricted to the palm. Identifying the median nerve in this manner ensures that median nerves that bifurcate proximal to the flexor retinaculum are recognized before dividing the flexor retinaculum. Duplex median nerves also have an increased risk of iatrogenic damage during infraretinacular ECTR. There is a learning curve with SRECTR. Before using this technique it is recommended that time is
spent in the fresh frozen cadaver laboratory developing the necessary dissecting skills so that it can be undertaken safely. It is essential that surgeons performing SRECTR have clear view of the anatomy before cutting the flexor retinaculum. This is especially important in the presence of large aberrant muscles that cross the midline on the palmar surface of the flexor retinaculum, and which need to be dissected in layers. Muscles that cross the midline of the flexor retinaculum can be very large and it may not be possible to safely dissect them in layers while maintaining a good field of vision. When this occurs, conversion to an open procedure is necessary to avoid inadvertent division of aberrant nerves. In our opinion, patients presenting with CTS with a history of CTR, flexor tenosynovitis associated with a connective tissue disorder or tumours in the carpal canal should be treated by OCTR. Acknowledgements We would like to acknowledge the clinical and research work of Shannon Edwick and Dr. Jessica Scoullar, as well as the time and effort provided by the patient group.
Conflict of interests None declared.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
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