WRIST AND HAND
Carpal tunnel release with subneural reconstruction of the transverse carpal ligament compared with isolated open and endoscopic release X. Zhang, Y. Li, S. Wen, H. Zhu, X. Shao, Y. Yu From Shanhaiguan Bridge Plant Hospital, Qinhuangdao, China
X. Zhang, MD, PhD, Orthopaedic Surgeon, Professor, Hand Surgery Department S. Wen, MD, PhD, Orthopaedic Surgeon, Professor H. Zhu, MD, PhD, Orthopaedic Surgeon The Second Hospital of Qinhuangdao, Changli, Qinhuangdao, Hebei, 066600, China. Y. Li, MD, PhD, Orthopaedic Surgeon Shanhaiguan Bridge Plant Hospital, Qinhuangdao, Hebei, 066200, China X. Shao, MD, PhD, Orthopaedic Surgeon, Professor Y. Yu, MD, PhD, Orthopaedic Surgeon, Professor Third Hospital of Hebei Medical University, Shijizhuang, Hebei, 050051, China. Correspondence should be sent to Dr X. Zhang; e-mail: [email protected] ©2015 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.97B2. 34423 $2.00 Bone Joint J 2015;97-B:221–8. Received 7 May 2014; Accepted after revision 17 October 2014
We report a new surgical technique of open carpal tunnel release with subneural reconstruction of the transverse carpal ligament and compare this with isolated open and endoscopic carpal tunnel release. Between December 2007 and October 2011, 213 patients with carpal tunnel syndrome (70 male, 143 female; mean age 45.6 years; 29 to 67) were recruited from three different centres and were randomly allocated to three groups: group A, open carpal tunnel release with subneural reconstruction of the transverse carpal ligament (n = 68); group B, isolated open carpal tunnel release (n = 92); and group C, endoscopic carpal tunnel release (n = 53). At a mean final follow-up of 24 months (22 to 26), we found no significant difference between the groups in terms of severity of symptoms or lateral grip strength. Compared with groups B and C, group A had significantly better functional status, cylindrical grip strength and pinch grip strength. There were significant differences in Michigan Hand Outcome scores between groups A and B, A and C, and B and C. Group A had the best functional status, cylindrical grip strength, pinch grip strength and Michigan Hand Outcome score. Subneural reconstruction of the transverse carpal ligament during carpal tunnel decompression maximises hand strength by stabilising the transverse carpal arch. Cite this article: Bone Joint J 2015;97-B:221–8
Carpal tunnel syndrome (CTS) affects over 60 million people worldwide.1 If conservative management fails, surgical release of the median nerve is warranted. Almost all surgical procedures require division of the transverse carpal ligament (TCL) to relieve pressure on the median nerve.2,3 However, this may result in decreased grip strength post-operatively, as the TCL plays a key role in the digital flexor pulley system. In a retrospective study of 113 patients who underwent open carpal tunnel release (CTR), Pavlidis et al4 reported that the most common symptom-related complaint was weakness in the hand. In a randomised double-blind controlled trial, Dias et al5 found that the results of lengthening the TCL were similar to those of isolated division. They concluded that there was no identifiable benefit in lengthening the TCL when decompressing the carpal tunnel. Mlakar et al6 found that grip strength became weaker after division of the TCL, and indicated that wearing a wrist orthosis did not compensate for the loss of grip strength. Currently, open CTR with reconstruction of the TCL has been advocated to restore wrist kinematics and grip strength.4
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The aim of this study was to assess the effect of open CTR with subneural reconstruction of the TCL. We compared the results of this with those of isolated open CTR and endoscopic CTR without TCL reconstruction. As it is a minimally invasive surgical procedure, endoscopic CTR might be expected to achieve better results than isolated open CTR.7 However, no study has compared these two procedures with open CTR and subneural reconstruction of the TCL.
Patients and Methods The study was approved by the institutional review boards of the hospitals involved. Informed consent and Health Insurance Portability and Accountability Act consent were obtained from each patient. Between December 2007 and October 2011, 739 patients with unilateral CTS who had attended three centres were randomly assigned to undergo CTR with subneural TCL reconstruction, isolated open CTR, or endoscopic CTR. Patients were selected on the following basis: symptoms lasting at least three months or an inadequate response to conservative (i.e. nonsurgical) treatment after at least six weeks. 221
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Table I. Demographic data on the 213 patients included in the study Total patients (n = 213)
Group A (n = 68)
Group B (n = 92)
Group C (n = 53)
Men Women Dominant hand Non-dominant hand Mean age (yrs) (range) Manual labour (n, %) Office work (n, %) Householder work (n, %) Worker's compensation (n, %) Moderate CTS (n, %) Severe CTS (n, %) Centre I Centre II Centre III
21 47 41 27 45 (32 to 64) 22 (32) 5 (7) 29 (43) 12 (18) 49 (72) 19 (28) 25 23 20
33 59 55 37 47 (29 to 67) 35 (38) 9 (10) 34 (37) 14 (15) 70 (76) 22 (24) 34 28 30
16 37 32 21 44 (34 to 65) 18 (35) 5 (9) 20 (38) 10 (19) 41 (77) 12 (23) 18 20 15
CTS, carpal tunnel syndrome
Diagnosis was based on the criteria established by the British Society for Surgery of the Hand (2003). These included patient profile, signs and symptoms, and provocative tests (Tinel8, tap or percussion test of the median nerve at the proximal wrist crease and the Phalen forced9 wrist flexion test).10 The severity of CTS was also defined based on this guide, including mild (intermittent paraesthesia), moderate (constant paraesthesia; reversible numbness and/or pain), or severe (constant numbness or pain; muscle wasting and/ or weakness of the thumb muscles). We excluded patients with mild symptoms or previous injuries to the limb; patients with bilateral involvement; patients who underwent neurolysis of the epineurium, because this cannot be carried out endoscopically;11 patients with diabetes or gout; patients with a cyst or tumour in the upper limb and those with connective tissue diseases (including lupus, scleroderma, polymyositis, Marfan’s syndrome, rheumatoid arthritis and psoriatic arthritis). These conditions were confirmed based on the presentation, laboratory tests and unexpected intra-operative findings. Patients who could not complete follow-up were also excluded. Thus, after patients with any of the above conditions were excluded, a total of 213 patients were included and divided into groups A (CTR with subneural reconstruction of the TCL, n = 68), B (isolated open CTR, n = 92), and C (endoscopic CTR, n = 53) using the block randomisation method. Each centre performed all of the procedures. The demographic details of all patients included in the study are given in Table I. Pre- and post-operatively (at one, three, six, 12, 18 and 24 months), each patient was assessed for severity of symptoms (11 items) and functional status (eight items) using the Boston Carpal Tunnel (Levine–Katz) Questionnaire.12 Each item ranges from 1 point (best) to 5 points (worst). The score totals used for severity of symptoms are categorised into asymptomatic (11), mild (12 to 22), moderate (23 to 33), severe (34 to 44) and very severe (45 to 55). Function scores are grouped into asymptomatic (8), mild (9 to 16), moderate (17 to 24), severe (25 to 32) and very severe (33
to 40). At the same intervals, using a dynamometer, we measured strength for three grip types; cylindrical, lateral and pinch. We use the Michigan Hand Questionnaire13 to assess the hand pre- and post-operatively. These data are shown in Table II. The operation was performed under axillary blockade with a pneumatic tourniquet to control bleeding. We started a 3 cm longitudinal incision just distal to the wrist flexion crease and slightly ulnar to the midline of the wrist and extended it distally in line with the third web space. The parallel palmar fascia fibres over the TCL were raised and retracted in a radial direction to expose the TCL (Fig. 1). The proximal half of the TCL was incised longitudinally about 5 mm from the origin of the hypothenar muscles. The distal half of the TCL was incised longitudinally along the ulnar border of the median nerve. To prevent recurrence of compression, a 4 mm-wide portion of the TCL over the median nerve and a delta-shaped area of the distal radial leaf of the TCL were removed (Figs 2 to 4). We took great care to avoid damage to any anatomical variant of the recurrent motor nerve: in these cases, the branch of the nerve was isolated and protected to prevent inadvertent injury. The median nerve was then isolated and elevated from the underlying flexor tendons (Fig. 5). The proximal radial leaf of the TCL was passed beneath the median nerve and sutured to the distal ulnar leaf, under tension and with overlap, using 3/0 absorbable sutures (Figs 6 and 7). The 2 cm distal antebrachial fascia (in green, Fig. 2) and the aponeurosis over the median nerve, about 1 cm in width, were removed with dissecting scissors to prevent possible nerve entrapment. The incision was closed in a routine fashion. After the operation, in order to relieve tension generated by bowstringing of the tendons on the reconstructed TCL, the wrist was positioned in slight extension with a volar splint. For the patient’s comfort, active movement of the fingers started two days after surgery. The splint was removed after two weeks, and gradual resumption of normal use of the hand was encouraged. THE BONE & JOINT JOURNAL
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Table II. Patient symptoms, functional status and grip strength (median, standard deviation (SD)) pre-operatively and post-operatively Post-operative Time interval
Pre-operative
Boston Questionnaire (symptom) Group A 39.5 (SD 6.1) Group B 37.5 (SD 6.1) Group C 38 (SD 6.1) Boston Questionnaire (function) Group A 27.3 (SD 6.6) Group B 26.6 (SD 7.3) Group C 28.6 (SD 5.5) Cylindrical grip strength (%) Group A 71.8 (SD 17.5) Group B 73 (SD 17.5) Group C 74.6 (SD 15.8) Lateral grip strength (%) Group A 76.8 (SD 13.4) Group B 78 (SD 17.6) Group C 72.3 (SD 16.3) Pinch grip strength (%) Group A 75.8 (SD 16.3) Group B 73 (SD 23.1) Group C 76.3 (SD 15.3) MHO score Group A 45.2 (SD 14.4) Group B 48.5 (SD 15.9) Group C 43.2 (SD 12.1)
Month 1
Month 3
Month 6
Month 12
Month 18
Month 24
22.8 (SD 11.1) 23.2 (SD 12.3) 19.8 (SD 12.3)
13.4 (SD 8.4) 14.2 (SD 9.5) 13.9 (SD 10.8)
6.4 (SD 5.6) 6.2 (SD 5.2) 5.7 (SD 6.4)
5.1 (SD 5.7) 4.9 (SD 4.2) 4.8 (SD 4.1)
4.6 (SD 5.3) 4.2 (SD 5.9) 4.0 (SD 4.8)
4.3 (SD 5.0) 4.4 (SD 5.5) 4.7 (SD 5.6)
6.3 (SD 4.1) 10.4 (SD 7.2) 6.9 (SD 5.3)
5.1 (SD 3.9) 9.3 (SD 7.5) 6.8 (SD 5.2)
4.5 (SD 3.7) 6.9 (SD 6.6) 6.2 (SD 6.3)
3.5 (SD 2.9) 6.5 (SD 5.8) 6.8 (SD 5.1)
3.1 (SD 3.3) 5.9 (SD 6.3) 6.5 (SD 7.1)
3.3 (SD 3.6) 6.8 (SD 5.2) 6.2 (SD 6.5)
68.7 (SD 14.3) 77.8 (SD 18.6) 80 (SD 15.6)
74.7 (SD 14.5) 84.4 (SD 13.7) 87.2 (SD 13.5)
87.9 (SD 12.1) 95.7 (SD 14.6) 94.2 (SD 11.5) 87.4 (SD 12.8) 88.2 (SD 10.9) 85.9 (SD 17.2) 89.9 (SD 12.2) 87.4 (SD 14.1) 87 (SD 12.3)
96.1 (SD 18.2) 87 (SD 15.7) 86.9 (SD 17.6)
62.3 (SD 15.7) 77 (SD 15.6) 80 (SD 13.9)
82.8 (SD 18.1) 85.7 (SD 19.5) 84.9 (SD 15)
86.7 (SD 12.8) 92.2 (SD 16.5) 96 (SD 14.7) 84.9 (SD 18.4) 89.7 (SD 17.4) 90.1 (SD 20.6) 86.5 (SD 13.6) 88.5 (SD 10.9) 92.1 (SD 14.7)
97.6 (SD 12.4) 88.4 (SD 18.3) 92.5 (SD 12.5)
71.4 (SD 18.5) 72 (SD 19.3) 74 (SD 11.3)
77.4 (SD 16.4) 75.5 (SD 18.1) 78.3 (SD 12.9)
95 (SD 16.4) 96.5 (SD 17.3) 94 (SD 17.9) 82.3 (SD 22.2) 80.8 (SD 17.7) 83.3 (SD 24.2) 80.7 (SD 16.5) 82.5 (SD 12.4) 86.1 (SD 12.5)
96.1 (SD 17.3) 81.5 (SD 17.8) 84.3 (SD 16.1)
-
-
-
91.2 (SD 7.2) 84.4 (SD 8.4) 86.2 (SD 7.6)
89.5 (SD 12.6) 76.3 (SD 21.6) 81.5 (SD 14.8) -
Group A, carpal tunnel release (CTR) with subneural plasty of the transverse carpal ligament; group B, isolated open CTR; group C, endoscopic CTR; strength has added 6% at the dominant side. Percentages show involved hand compared with opposite normal hand. MHO, Michigan Hand Outcome; SD, standard deviation
Fig. 1
Fig. 2
Diagrammatic representation of the parallel palmar fascia being raised and retracted in a radial direction to expose the transverse carpal ligament (TCL).
Diagrammatic representation of the incisions on the TCL, which are marked with red lines. The green area indicates the location of the excised tissue.
Isolated open CTR (group B). The approach used was the same as for the above procedures. The TCL, antebrachial fascia and aponeurosis were incised longitudinally in the conventional fashion. No additional procedures were undertaken. The wound was closed in the routine manner. A volar splint was applied to keep the wrist in a neutral position for seven to 14 days. Other post-operative protocols were the same. VOL. 97-B, No. 2, FEBRUARY 2015
Endoscopic CTR (group C). We used the two-portal endoscopic method described by Uchiyama et al,14 (Smith & Nephew Endoscopy, Andover, Massachusetts). Each of the two skin incisions was 1 cm long. After surgery, a soft dressing was applied and patients were advised to begin immediate finger range of movement exercises and to use the hand for daily activities as tolerated.
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Fig. 3
Fig. 5
Intra-operative photograph of the completed incision according to Figure 2.
Intra-operative photograph of the raised median nerve.
Fig. 4
Fig. 6
Intra-operative photograph of the exposed median nerve with the portions of the divided transverse carpal ligament retracted.
Diagrammatic representation of the proximal radial leaf of the transverse carpal ligament (TCL) being passed beneath the median nerve and then sutured to the distal ulnar leaf of the TCL over the flexor tendons.
Outcome evaluation. All assessments were performed by
the same senior hand surgeons (YL, HZ, YY) in each centre. To improve consistency of strength between dominant and non-dominant hands, we based the scores for analysis on the premise that the grip strength was 6% higher on the dominant side than on the non-dominant side.15 All measurements were compared with those recorded for the opposite side and expressed as a percentage. We recorded the presence of any flexor tendon bowstringing, defined as protrusion of the flexor tendon during flexion. At final followup, patients reported on scar pain and the appearance of the wrists using the Michigan Hand Outcome scores. The Michigan Hand Outcome score uses a five-point response scale for appearance, which was converted to a percentage and compared with the opposite side.
Statistical analysis. Quantitative variables were given as mean and standard deviation (SD) for items with a normal distribution, or as median and interquartile range (IQR) for those without a normal distribution. We used Pearson’s chisquared test to compare categorical variables and check for normal distribution, and the Mann–Whitney U test for symmetric and asymmetric distributions. A p-value < 0.05 was considered statistically significant. The collected data were analysed using Statistical Package for Social Sciences v13.0 (SPSS Inc., Chicago, Illinois).
Results Pre-operatively, the median severity of symptom scores for groups A, B and C were 39.5 (SD 6.1), 37.5 (SD 6.1) and 38 (SD 6.1), respectively. The median functional status scores THE BONE & JOINT JOURNAL
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stringing than groups B and C (Table III). There were also significant differences in appearance between groups A and B (p < 0.001), A and C (p < 0.001) and B and C (p = 0.044, all t-test), and between groups A and B, A and C, and B and C in the mean/median Michigan Hand Outcome scores (all p < 0.001, t-test) (Table III). In summary, all groups obtained similar improvements in symptoms and lateral grip strength. Group A had statistically better results for functional recovery, cylindrical grip and pinch grip strength, flexor tendon bowstringing and Michigan Hand Outcome scores. Group C had better results for pain and appearance.
Fig. 7 Intra-operative photograph of the completed TCL reconstruction.
of groups A, B and C were 27.3 (SD 6.6), 26.6 (SD 7.3) and 28.6 (SD 5.5), respectively (Table II). No revision surgery was performed in any group. At a mean final follow-up of two years (22 to 26) the median severity of symptom scores of groups A, B and C were 4.3 (SD 5), 4.4 (SD 5.5) and 4.7 (SD 5.6), respectively, and the median functional status scores 3.3 (SD 3.6), 6.8 (SD 5.2) and 6.2 (SD 6.5), respectively. The pre- and post-operative cylindrical, lateral and grip strengths of the groups, as well as the Michigan Hand Outcome scores, are given in Table II. Bowstringing of the flexor tendon was not noted in group A at 24 months, but was present in 66 (72%) patients in group B and 48 (91%) of patients in group C. At the same follow-up, using the Michigan Hand Outcome Questionnaire, the median scar pain in the wrist was 8.2 (SD 7), 8 (SD 6.5) and 5.3 (SD 7.3) in groups A, B and C, respectively. The median appearance of the wrist was 90.8% (SD 8.1), 89.5% (SD 9.6) and 96.5% (SD 5.2) in groups A, B and C, respectively. The graphs of consecutive assessments showed that group A had quicker recovery of function but slower recovery of grip strength, although this recovered within one to six months. The graphs for groups B and C were similar (Fig. 8). No significant difference was found between the groups in terms of gender, age or hand dominance (Table III). We found no significant difference in the pre-operative severity of symptoms, functional status, cylindrical grip strength, lateral grip strength, pinch grip strength or Michigan Hand Outcome scores (Table III). At final follow-up, there was no significant difference between the groups in terms of severity of symptoms or lateral grip strength (Table III). Group A gave significantly better results in terms of functional status, pinch grip strength, cylindrical grip strength and flexor tendon bowVOL. 97-B, No. 2, FEBRUARY 2015
Discussion The flexor retinaculum is a strong, fibrous band which arches over the carpus, converting the deep groove on the front of the carpal bones into a tunnel. It includes, the distal deep fascia of the forearm, TCL and the aponeurosis between the thenar and hypothenar muscles.16 A successful CTR usually requires division of all these structures. The first open CTR was reportedly performed by Herbert Galloway in 1924.17 Endoscopic CTR was first described by Okutsu et al in 1989.18 The flexor retinaculum protects the median nerve, prevents bowstringing of the flexor tendons and maximises grip strength. The TCL is the largest and strongest ligament of the wrist, enhancing grip strength and providing stability to the whole hand. In two cadaver studies, Garcia-Elias et al19 found that division of the TCL reduced stiffness of the global transverse carpal arch by a mean of 7.5% and Fisk20 showed a decrease in carpal concavity and widening of the carpal tunnel by a mean of 3 mm. In a biomechanical cadaver study, Fuss and Wagner21 also found widening of the carpal tunnel, loss of anatomical attachment of the thenar and hypothenar muscles and decreased strength of the hand. In order to reduce the described negative effects, Netscher22 recommended reconstruction of the TCL after open CTR. Based on several experimental and clinical studies, Altissimi23 also recommended TCL reconstruction, because the ability of a patient to return to work is directly related to post-operative weakness and the delay in recovery of grip strength, even though the endoscopic techniques have been developed to achieve a more rapid recovery. Several techniques of reconstruction have been reported in the literature. Seitz and Lall24 reconstructed the TCL by Z-lengthening in 56 patients. Compared with an isolated open release, grip strength returned to near normal earlier, with a mean improvement of 18%. Jakab, Ganos and Cook25 lengthened the ligament 6 mm to 7 mm in a stepwise fashion. In a review of 104 hands, 97 (93%) obtained complete relief of symptoms with no loss of grip strength. In a double-blinded study, Xu, Huang and Hou26 concluded that patients who underwent coronal Z-type TCL lengthening achieved better function and greater satisfaction than with conventional CTR. Duché and Trabelsi27 found that TCL reconstruction with a Canaletto implant (Eurymed,
30 27 24 21 18 15 12 9 6 3
Cylindrical grip strength (%)
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Function
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Group A Group B Group C
Pre-op 1
3
6
12 18 Duration (mths)
100 90 80 70 60 50 40 30 20 10
24
Group A Group B Group C
Pre-op 1
3
Fig. 8a
100 90 80 70 60 50 40 30 20 10
Group A Group B Group C
Pre-op 1
3
12 6 Duration (mths)
18
24
Fig. 8b
Pinch grip strength (%)
Lateral grip strength (%)
100 90 80 70 60 50 40 30 20 10
6 12 Duration (mths)
18
24
Fig. 8c
Group A Group B Group C
Pre-op 1
3
18 6 12 Duration (mths)
24
Fig. 8d
Graphs showing the parameters after three methods of carpal tunnel release (CTR), i.e. CTR with subneural TCL plasty (group A, n = 68), isolated open CTR (group B, n = 92) and endoscopic CTR (group C, n = 53). Mean functional status based on the Boston Carpal Tunnel Questionnaire; mean percentages of cylindrical grip strength compared with those recorded for the opposite hand; lateral grip strength and pinch grip strength.
Nîmes, France) achieved better results than open CTR. In a cadaver study, Pavlidis et al4 showed that TCL lengthening increases the capacity of the carpal tunnel by 31% to 44%, regardless of the surgical technique used. Although reconstruction of the TCL over the median nerve improves grip strength, it may compromise the decompression. In contrast to the other procedures, our TCL reconstruction creates a new carpal tunnel beneath the median nerve. Thus, the kinematics of the carpal tunnel can be restored without the risk of recurrent nerve entrapment. The abductor pollicis brevis is an important muscle innervated by the median nerve. However, in our study we did not test its strength in isolation, because its isolated function is obscured by a number of synergists of other thenar muscles. There is, however, a strong correlation between pinch strength and the strength of the muscle.28 Our study shows that reconstruction of the TCL beneath the median nerve gives better hand function than isolated open and endoscopic TCL division. All three methods
result in similar symptomatic improvement. The incidence of scar pain is lower after endoscopic surgery. Possibly, because of the absence of bowstringing of the flexor tendons, TCL reconstruction achieves a better appearance, even though endoscopic surgery is performed through small incisions. Overall, patients who underwent subneural reconstruction of the TCL had a higher mean Michigan Hand Outcome score than those who underwent isolated open and endoscopic CTR. Our consecutive assessments showed that patients who underwent reconstruction of the TCL had better subsequent hand function. However, their recovery of grip strength was slower, which may be due to our post-operative immobilisation of the wrist. Hand function and strength recovered within one to six months. Our retrospective study has limitations. Although the patients were randomly allocated, bias may have arisen owing to the involvement of three centres and several surgeons.
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Table III. Statistical analysis (t-test) between the groups p-value Gender Age Dominance Severity of symptoms Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 Functional status Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 Cylindrical grip strength Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 Lateral grip strength Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 Pinch grip strength Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 MHO score Pre-op Month 12 Month 24 Bowstring Pain Appearance
Groups A and B
Groups A and C
Groups B and C
0.053 0.133 0.105
0.205 0.107 0.126
0.113 0.462 0.113
0.084 0.425 0.206 0.264 0.336 0.418 0.267
0.204 0.230 0.674 0.777 0.381 0.402 0.423
0.457 0.719 0.739 0.773 0.520 0.254 0.329
0.114 0.001 0.001 0.001 0.003 0.001 0.015
0.612 0.079 0.030 0.026 0.031 0.001 0.001
0.082 0.018 0.045 0.231 0.452 0.519 0.248
0.905 0.004 0.001 0.001 0.015 0.001 0.002
0.490 0.001 0.001 0.009 0.032 0.001 0.001
0.273 0.219 0.169 0.367 0.451 0.266 0.347
0.352 0.033 0.255 0.427 0.250 0.336 0.754
0.477 0.011 0.374 0.126 0.293 0.521 0.329
0.087 0.007 0.786 0.352 0.224 0.078 0.128
0.266 0.341 0.525 0.004 0.012 0.001 0.006
0.753 0.563 0.094 0.008 0.032 0.016 0.025
0.182 0.022 0.007 0.269 0.531 0.756 0.392
0.478 0.002 0.001 0.004 0.803 0.001
0.216 0.012 0.001 0.020 0.001 0.001
0.321 0.006 0.001 4.84 0.001 0.044
Strength has added 6% at the dominant side MHO, Michigan Hand Outcome
Subneural reconstruction of the TCL offers an alternative to isolated open and endoscopic CTR and maximises hand strength by stabilising the transverse carpal arch. VOL. 97-B, No. 2, FEBRUARY 2015
Author contributions X. Zhang Contributed to study design, Approved the final manuscript. Y. Li: Study implementation. S. Wen: Study implementation. H. Zhu: Study implementation.
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X. Shao: Refinement of the study protocol. Y. Yu: Refinement of the study protocol.. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by G. Scott and first proof edited by A.C. Ross.
References 1. Rossignol M, Stock S, Patry L, Armstrong B. Carpal tunnel syndrome: what is attributable to work? The Montreal study. Occup Environ Med 1997;54:519–523. 2. Liong K, Lahiri A, Lee S, et al. Mid-motion deformation of median nerve during finger flexion: a new insight into the dynamic aetiology of carpal tunnel syndrome. Hand Surg 2013;18:193–202. 3. Yoshii Y, Ishii T, Tung WL, Sakai S, Amadio PC. Median nerve deformation and displacement in the carpal tunnel during finger motion. J Orthop Res 2013;31:1876– 1880. 4. Pavlidis L, Chalidis BE, Demiri E, Dimitriou CG. The effect of transverse carpal ligament lengthening on carpal tunnel volumetry: a comparison between four techniques. Ann Plast Surg 2010;65:480–484. 5. Dias JJ, Bhowal B, Wildin CJ, Thompson JR. Carpal tunnel decompression; is lengthening of the flexor retinaculum better than simple division? J Hand Surg Br 2004;29:271–276. 6. Mlakar M, Ramstrand N, Burger H, Vidmar G. Effect of custom-made and prefabricated orthoses on grip strength in persons with carpal tunnel syndrome. Prosthet Orthot Int 2013;38:193–198. 7. Kohanzadeh S, Herrera FA, Dobke M. Outcomes of open and endoscopic carpal tunnel release: a meta-analysis. Hand (N Y) 2012;7:247–251. 8. Ansari NN, Adelmanesh F, Naghdi S, Mousavi S. The relationship between symptoms, clinical tests and nerve conduction study findings in carpal tunnel syndrome. Electromyogr Clin Neurophysiol 2009;49:53–57. 9. Yayama T, Kobayashi S, Awara K, et al. Intraneural blood flow analysis during an intraoperative Phalen's test in carpal tunnel syndrome. J Orthop Res 2010;28:1022– 1025. 10. Szabo RM, Slater RR Jr, Farver TB, Stanton DB, Sharman WK. The value of diagnostic testing in carpal tunnel syndrome. J Hand Surg Am 1999;24:704–714. 11. Blair WF, Goetz DD, Ross MA, Steyers CM, Chang P. Carpal tunnel release with and without epineurotomy: a comparative prospective trial. J Hand Surg Am 1996;21:655–661. 12. Levine DW, Simmons BP, Koris MJ, et al. A self-administered questionnaire for the assessment of severity of symptoms and functional status in carpal tunnel syndrome. J Bone Joint Surg [Am] 1993;75-A:1585–1592.
13. Chung KC, Pillsbury MS, Walters MR, Hayward RA. Reliability and validity testing of the Michigan Hand Outcomes Questionnaire. J Hand Surg Am 1998;23:575– 587. 14. Uchiyama S, Yasutomi T, Momose T, et al. Carpal tunnel pressure measurement during two-portal endoscopic carpal tunnel release. Clin Biomech (Bristol, Avon) 2010;25:893–898. 15. Crosby CA, Wehbé MA, Mawr B. Hand strength: normative values. J Hand Surg Am 1994;19:665–670. 16. Tanabe T, Okutsu I. An anatomical study of the palmar ligamentous structures of the carpal canal. J Hand Surg Br 1997;22:754–757. 17. Amadio PC. The first carpal tunnel release? J Hand Surg Br 1995;20:40–41. 18. Okutsu I, Ninomiya S, Takatori Y, Ugawa Y. Endoscopic management of carpal tunnel syndrome. Arthroscopy 1989;5:11–18. 19. Garcia-Elias M, An KN, Cooney WP 3rd, Linscheid RL, Chao EY. Stability of the transverse carpal arch: an experimental study. J Hand Surg Am 1989;14(2Pt1):277– 282. 20. Fisk GR. The influence of the transverse carpal ligament (flexor retinaculum) on stability. Ann Chir Main 1984;3:297–299 (article in English, French). 21. Fuss FK, Wagner TF. Biomechanical alterations in the carpal arch and hand muscles after carpal tunnel release: a further approach toward understanding the function of the flexor retinaculum and the cause of postoperative grip weakness. Clin Anat 1996;9:100–108. 22. Netscher DT. The benefit of transverse carpal ligament reconstruction following open carpal tunnel release. Plast Reconstr Surg 2003;111:2020–2022. 23. Altissimi M. Critical Appraisal of Transverse Carpal Ligament Reconstruction. Theoretical, Experimental, and Clinical Considerations. Carpal Tunnel Syndrome. Springer Berlin Heidelberg, 2007;239–240. 24. Seitz WH, Lall A. Open carpal tunnel release with median neurolysis and Z-plasty reconstruction of the transverse carpal ligament. Curr Orthop Pract 2013;24:53–57. 25. Jakab E, Ganos D, Cook FW. Transverse carpal ligament reconstruction in surgery for carpal tunnel syndrome: a new technique. J Hand Surg Am 1991;16:202–206. 26. Xu L, Huang F, Hou C. Treatment for carpal tunnel syndrome by coronal Z-type lengthening of the transverse carpal ligament. J Pak Med Assoc 2011;61:1068–1071. 27. Duché R, Trabelsi A. The Canalettoimplant for reconstructing transverse carpal ligament in carpal tunnel surgery; surgical technique and cohort prospective study about 400 Canaletto cases versus 400 cases with open carpal tunnel surgery. Chir Main 2010;29:352–359. 28. Schreuders TA, Selles RW, Roebroeck ME, Stam HJ. Strength measurements of the intrinsic hand muscles: a review of the development and evaluation of the Rotterdam intrinsic hand myometer. J Hand Ther 2006;19:393–401.
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Carpal tunnel release with subneural reconstruction of the transverse carpal ligament compared with isolated open and endoscopic release X. Zhang, Y. Li, S. Wen, H. Zhu, X. Shao, Y. Yu From Shanhaiguan Bridge Plant Hospital, Qinhuangdao, China
X. Zhang, MD, PhD, Orthopaedic Surgeon, Professor, Hand Surgery Department S. Wen, MD, PhD, Orthopaedic Surgeon, Professor H. Zhu, MD, PhD, Orthopaedic Surgeon The Second Hospital of Qinhuangdao, Changli, Qinhuangdao, Hebei, 066600, China. Y. Li, MD, PhD, Orthopaedic Surgeon Shanhaiguan Bridge Plant Hospital, Qinhuangdao, Hebei, 066200, China X. Shao, MD, PhD, Orthopaedic Surgeon, Professor Y. Yu, MD, PhD, Orthopaedic Surgeon, Professor Third Hospital of Hebei Medical University, Shijizhuang, Hebei, 050051, China. Correspondence should be sent to Dr X. Zhang; e-mail: [email protected] ©2015 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.97B2. 34423 $2.00 Bone Joint J 2015;97-B:221–8. Received 7 May 2014; Accepted after revision 17 October 2014
We report a new surgical technique of open carpal tunnel release with subneural reconstruction of the transverse carpal ligament and compare this with isolated open and endoscopic carpal tunnel release. Between December 2007 and October 2011, 213 patients with carpal tunnel syndrome (70 male, 143 female; mean age 45.6 years; 29 to 67) were recruited from three different centres and were randomly allocated to three groups: group A, open carpal tunnel release with subneural reconstruction of the transverse carpal ligament (n = 68); group B, isolated open carpal tunnel release (n = 92); and group C, endoscopic carpal tunnel release (n = 53). At a mean final follow-up of 24 months (22 to 26), we found no significant difference between the groups in terms of severity of symptoms or lateral grip strength. Compared with groups B and C, group A had significantly better functional status, cylindrical grip strength and pinch grip strength. There were significant differences in Michigan Hand Outcome scores between groups A and B, A and C, and B and C. Group A had the best functional status, cylindrical grip strength, pinch grip strength and Michigan Hand Outcome score. Subneural reconstruction of the transverse carpal ligament during carpal tunnel decompression maximises hand strength by stabilising the transverse carpal arch. Cite this article: Bone Joint J 2015;97-B:221–8
Carpal tunnel syndrome (CTS) affects over 60 million people worldwide.1 If conservative management fails, surgical release of the median nerve is warranted. Almost all surgical procedures require division of the transverse carpal ligament (TCL) to relieve pressure on the median nerve.2,3 However, this may result in decreased grip strength post-operatively, as the TCL plays a key role in the digital flexor pulley system. In a retrospective study of 113 patients who underwent open carpal tunnel release (CTR), Pavlidis et al4 reported that the most common symptom-related complaint was weakness in the hand. In a randomised double-blind controlled trial, Dias et al5 found that the results of lengthening the TCL were similar to those of isolated division. They concluded that there was no identifiable benefit in lengthening the TCL when decompressing the carpal tunnel. Mlakar et al6 found that grip strength became weaker after division of the TCL, and indicated that wearing a wrist orthosis did not compensate for the loss of grip strength. Currently, open CTR with reconstruction of the TCL has been advocated to restore wrist kinematics and grip strength.4
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The aim of this study was to assess the effect of open CTR with subneural reconstruction of the TCL. We compared the results of this with those of isolated open CTR and endoscopic CTR without TCL reconstruction. As it is a minimally invasive surgical procedure, endoscopic CTR might be expected to achieve better results than isolated open CTR.7 However, no study has compared these two procedures with open CTR and subneural reconstruction of the TCL.
Patients and Methods The study was approved by the institutional review boards of the hospitals involved. Informed consent and Health Insurance Portability and Accountability Act consent were obtained from each patient. Between December 2007 and October 2011, 739 patients with unilateral CTS who had attended three centres were randomly assigned to undergo CTR with subneural TCL reconstruction, isolated open CTR, or endoscopic CTR. Patients were selected on the following basis: symptoms lasting at least three months or an inadequate response to conservative (i.e. nonsurgical) treatment after at least six weeks. 221
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Table I. Demographic data on the 213 patients included in the study Total patients (n = 213)
Group A (n = 68)
Group B (n = 92)
Group C (n = 53)
Men Women Dominant hand Non-dominant hand Mean age (yrs) (range) Manual labour (n, %) Office work (n, %) Householder work (n, %) Worker's compensation (n, %) Moderate CTS (n, %) Severe CTS (n, %) Centre I Centre II Centre III
21 47 41 27 45 (32 to 64) 22 (32) 5 (7) 29 (43) 12 (18) 49 (72) 19 (28) 25 23 20
33 59 55 37 47 (29 to 67) 35 (38) 9 (10) 34 (37) 14 (15) 70 (76) 22 (24) 34 28 30
16 37 32 21 44 (34 to 65) 18 (35) 5 (9) 20 (38) 10 (19) 41 (77) 12 (23) 18 20 15
CTS, carpal tunnel syndrome
Diagnosis was based on the criteria established by the British Society for Surgery of the Hand (2003). These included patient profile, signs and symptoms, and provocative tests (Tinel8, tap or percussion test of the median nerve at the proximal wrist crease and the Phalen forced9 wrist flexion test).10 The severity of CTS was also defined based on this guide, including mild (intermittent paraesthesia), moderate (constant paraesthesia; reversible numbness and/or pain), or severe (constant numbness or pain; muscle wasting and/ or weakness of the thumb muscles). We excluded patients with mild symptoms or previous injuries to the limb; patients with bilateral involvement; patients who underwent neurolysis of the epineurium, because this cannot be carried out endoscopically;11 patients with diabetes or gout; patients with a cyst or tumour in the upper limb and those with connective tissue diseases (including lupus, scleroderma, polymyositis, Marfan’s syndrome, rheumatoid arthritis and psoriatic arthritis). These conditions were confirmed based on the presentation, laboratory tests and unexpected intra-operative findings. Patients who could not complete follow-up were also excluded. Thus, after patients with any of the above conditions were excluded, a total of 213 patients were included and divided into groups A (CTR with subneural reconstruction of the TCL, n = 68), B (isolated open CTR, n = 92), and C (endoscopic CTR, n = 53) using the block randomisation method. Each centre performed all of the procedures. The demographic details of all patients included in the study are given in Table I. Pre- and post-operatively (at one, three, six, 12, 18 and 24 months), each patient was assessed for severity of symptoms (11 items) and functional status (eight items) using the Boston Carpal Tunnel (Levine–Katz) Questionnaire.12 Each item ranges from 1 point (best) to 5 points (worst). The score totals used for severity of symptoms are categorised into asymptomatic (11), mild (12 to 22), moderate (23 to 33), severe (34 to 44) and very severe (45 to 55). Function scores are grouped into asymptomatic (8), mild (9 to 16), moderate (17 to 24), severe (25 to 32) and very severe (33
to 40). At the same intervals, using a dynamometer, we measured strength for three grip types; cylindrical, lateral and pinch. We use the Michigan Hand Questionnaire13 to assess the hand pre- and post-operatively. These data are shown in Table II. The operation was performed under axillary blockade with a pneumatic tourniquet to control bleeding. We started a 3 cm longitudinal incision just distal to the wrist flexion crease and slightly ulnar to the midline of the wrist and extended it distally in line with the third web space. The parallel palmar fascia fibres over the TCL were raised and retracted in a radial direction to expose the TCL (Fig. 1). The proximal half of the TCL was incised longitudinally about 5 mm from the origin of the hypothenar muscles. The distal half of the TCL was incised longitudinally along the ulnar border of the median nerve. To prevent recurrence of compression, a 4 mm-wide portion of the TCL over the median nerve and a delta-shaped area of the distal radial leaf of the TCL were removed (Figs 2 to 4). We took great care to avoid damage to any anatomical variant of the recurrent motor nerve: in these cases, the branch of the nerve was isolated and protected to prevent inadvertent injury. The median nerve was then isolated and elevated from the underlying flexor tendons (Fig. 5). The proximal radial leaf of the TCL was passed beneath the median nerve and sutured to the distal ulnar leaf, under tension and with overlap, using 3/0 absorbable sutures (Figs 6 and 7). The 2 cm distal antebrachial fascia (in green, Fig. 2) and the aponeurosis over the median nerve, about 1 cm in width, were removed with dissecting scissors to prevent possible nerve entrapment. The incision was closed in a routine fashion. After the operation, in order to relieve tension generated by bowstringing of the tendons on the reconstructed TCL, the wrist was positioned in slight extension with a volar splint. For the patient’s comfort, active movement of the fingers started two days after surgery. The splint was removed after two weeks, and gradual resumption of normal use of the hand was encouraged. THE BONE & JOINT JOURNAL
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Table II. Patient symptoms, functional status and grip strength (median, standard deviation (SD)) pre-operatively and post-operatively Post-operative Time interval
Pre-operative
Boston Questionnaire (symptom) Group A 39.5 (SD 6.1) Group B 37.5 (SD 6.1) Group C 38 (SD 6.1) Boston Questionnaire (function) Group A 27.3 (SD 6.6) Group B 26.6 (SD 7.3) Group C 28.6 (SD 5.5) Cylindrical grip strength (%) Group A 71.8 (SD 17.5) Group B 73 (SD 17.5) Group C 74.6 (SD 15.8) Lateral grip strength (%) Group A 76.8 (SD 13.4) Group B 78 (SD 17.6) Group C 72.3 (SD 16.3) Pinch grip strength (%) Group A 75.8 (SD 16.3) Group B 73 (SD 23.1) Group C 76.3 (SD 15.3) MHO score Group A 45.2 (SD 14.4) Group B 48.5 (SD 15.9) Group C 43.2 (SD 12.1)
Month 1
Month 3
Month 6
Month 12
Month 18
Month 24
22.8 (SD 11.1) 23.2 (SD 12.3) 19.8 (SD 12.3)
13.4 (SD 8.4) 14.2 (SD 9.5) 13.9 (SD 10.8)
6.4 (SD 5.6) 6.2 (SD 5.2) 5.7 (SD 6.4)
5.1 (SD 5.7) 4.9 (SD 4.2) 4.8 (SD 4.1)
4.6 (SD 5.3) 4.2 (SD 5.9) 4.0 (SD 4.8)
4.3 (SD 5.0) 4.4 (SD 5.5) 4.7 (SD 5.6)
6.3 (SD 4.1) 10.4 (SD 7.2) 6.9 (SD 5.3)
5.1 (SD 3.9) 9.3 (SD 7.5) 6.8 (SD 5.2)
4.5 (SD 3.7) 6.9 (SD 6.6) 6.2 (SD 6.3)
3.5 (SD 2.9) 6.5 (SD 5.8) 6.8 (SD 5.1)
3.1 (SD 3.3) 5.9 (SD 6.3) 6.5 (SD 7.1)
3.3 (SD 3.6) 6.8 (SD 5.2) 6.2 (SD 6.5)
68.7 (SD 14.3) 77.8 (SD 18.6) 80 (SD 15.6)
74.7 (SD 14.5) 84.4 (SD 13.7) 87.2 (SD 13.5)
87.9 (SD 12.1) 95.7 (SD 14.6) 94.2 (SD 11.5) 87.4 (SD 12.8) 88.2 (SD 10.9) 85.9 (SD 17.2) 89.9 (SD 12.2) 87.4 (SD 14.1) 87 (SD 12.3)
96.1 (SD 18.2) 87 (SD 15.7) 86.9 (SD 17.6)
62.3 (SD 15.7) 77 (SD 15.6) 80 (SD 13.9)
82.8 (SD 18.1) 85.7 (SD 19.5) 84.9 (SD 15)
86.7 (SD 12.8) 92.2 (SD 16.5) 96 (SD 14.7) 84.9 (SD 18.4) 89.7 (SD 17.4) 90.1 (SD 20.6) 86.5 (SD 13.6) 88.5 (SD 10.9) 92.1 (SD 14.7)
97.6 (SD 12.4) 88.4 (SD 18.3) 92.5 (SD 12.5)
71.4 (SD 18.5) 72 (SD 19.3) 74 (SD 11.3)
77.4 (SD 16.4) 75.5 (SD 18.1) 78.3 (SD 12.9)
95 (SD 16.4) 96.5 (SD 17.3) 94 (SD 17.9) 82.3 (SD 22.2) 80.8 (SD 17.7) 83.3 (SD 24.2) 80.7 (SD 16.5) 82.5 (SD 12.4) 86.1 (SD 12.5)
96.1 (SD 17.3) 81.5 (SD 17.8) 84.3 (SD 16.1)
-
-
-
91.2 (SD 7.2) 84.4 (SD 8.4) 86.2 (SD 7.6)
89.5 (SD 12.6) 76.3 (SD 21.6) 81.5 (SD 14.8) -
Group A, carpal tunnel release (CTR) with subneural plasty of the transverse carpal ligament; group B, isolated open CTR; group C, endoscopic CTR; strength has added 6% at the dominant side. Percentages show involved hand compared with opposite normal hand. MHO, Michigan Hand Outcome; SD, standard deviation
Fig. 1
Fig. 2
Diagrammatic representation of the parallel palmar fascia being raised and retracted in a radial direction to expose the transverse carpal ligament (TCL).
Diagrammatic representation of the incisions on the TCL, which are marked with red lines. The green area indicates the location of the excised tissue.
Isolated open CTR (group B). The approach used was the same as for the above procedures. The TCL, antebrachial fascia and aponeurosis were incised longitudinally in the conventional fashion. No additional procedures were undertaken. The wound was closed in the routine manner. A volar splint was applied to keep the wrist in a neutral position for seven to 14 days. Other post-operative protocols were the same. VOL. 97-B, No. 2, FEBRUARY 2015
Endoscopic CTR (group C). We used the two-portal endoscopic method described by Uchiyama et al,14 (Smith & Nephew Endoscopy, Andover, Massachusetts). Each of the two skin incisions was 1 cm long. After surgery, a soft dressing was applied and patients were advised to begin immediate finger range of movement exercises and to use the hand for daily activities as tolerated.
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Fig. 3
Fig. 5
Intra-operative photograph of the completed incision according to Figure 2.
Intra-operative photograph of the raised median nerve.
Fig. 4
Fig. 6
Intra-operative photograph of the exposed median nerve with the portions of the divided transverse carpal ligament retracted.
Diagrammatic representation of the proximal radial leaf of the transverse carpal ligament (TCL) being passed beneath the median nerve and then sutured to the distal ulnar leaf of the TCL over the flexor tendons.
Outcome evaluation. All assessments were performed by
the same senior hand surgeons (YL, HZ, YY) in each centre. To improve consistency of strength between dominant and non-dominant hands, we based the scores for analysis on the premise that the grip strength was 6% higher on the dominant side than on the non-dominant side.15 All measurements were compared with those recorded for the opposite side and expressed as a percentage. We recorded the presence of any flexor tendon bowstringing, defined as protrusion of the flexor tendon during flexion. At final followup, patients reported on scar pain and the appearance of the wrists using the Michigan Hand Outcome scores. The Michigan Hand Outcome score uses a five-point response scale for appearance, which was converted to a percentage and compared with the opposite side.
Statistical analysis. Quantitative variables were given as mean and standard deviation (SD) for items with a normal distribution, or as median and interquartile range (IQR) for those without a normal distribution. We used Pearson’s chisquared test to compare categorical variables and check for normal distribution, and the Mann–Whitney U test for symmetric and asymmetric distributions. A p-value < 0.05 was considered statistically significant. The collected data were analysed using Statistical Package for Social Sciences v13.0 (SPSS Inc., Chicago, Illinois).
Results Pre-operatively, the median severity of symptom scores for groups A, B and C were 39.5 (SD 6.1), 37.5 (SD 6.1) and 38 (SD 6.1), respectively. The median functional status scores THE BONE & JOINT JOURNAL
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stringing than groups B and C (Table III). There were also significant differences in appearance between groups A and B (p < 0.001), A and C (p < 0.001) and B and C (p = 0.044, all t-test), and between groups A and B, A and C, and B and C in the mean/median Michigan Hand Outcome scores (all p < 0.001, t-test) (Table III). In summary, all groups obtained similar improvements in symptoms and lateral grip strength. Group A had statistically better results for functional recovery, cylindrical grip and pinch grip strength, flexor tendon bowstringing and Michigan Hand Outcome scores. Group C had better results for pain and appearance.
Fig. 7 Intra-operative photograph of the completed TCL reconstruction.
of groups A, B and C were 27.3 (SD 6.6), 26.6 (SD 7.3) and 28.6 (SD 5.5), respectively (Table II). No revision surgery was performed in any group. At a mean final follow-up of two years (22 to 26) the median severity of symptom scores of groups A, B and C were 4.3 (SD 5), 4.4 (SD 5.5) and 4.7 (SD 5.6), respectively, and the median functional status scores 3.3 (SD 3.6), 6.8 (SD 5.2) and 6.2 (SD 6.5), respectively. The pre- and post-operative cylindrical, lateral and grip strengths of the groups, as well as the Michigan Hand Outcome scores, are given in Table II. Bowstringing of the flexor tendon was not noted in group A at 24 months, but was present in 66 (72%) patients in group B and 48 (91%) of patients in group C. At the same follow-up, using the Michigan Hand Outcome Questionnaire, the median scar pain in the wrist was 8.2 (SD 7), 8 (SD 6.5) and 5.3 (SD 7.3) in groups A, B and C, respectively. The median appearance of the wrist was 90.8% (SD 8.1), 89.5% (SD 9.6) and 96.5% (SD 5.2) in groups A, B and C, respectively. The graphs of consecutive assessments showed that group A had quicker recovery of function but slower recovery of grip strength, although this recovered within one to six months. The graphs for groups B and C were similar (Fig. 8). No significant difference was found between the groups in terms of gender, age or hand dominance (Table III). We found no significant difference in the pre-operative severity of symptoms, functional status, cylindrical grip strength, lateral grip strength, pinch grip strength or Michigan Hand Outcome scores (Table III). At final follow-up, there was no significant difference between the groups in terms of severity of symptoms or lateral grip strength (Table III). Group A gave significantly better results in terms of functional status, pinch grip strength, cylindrical grip strength and flexor tendon bowVOL. 97-B, No. 2, FEBRUARY 2015
Discussion The flexor retinaculum is a strong, fibrous band which arches over the carpus, converting the deep groove on the front of the carpal bones into a tunnel. It includes, the distal deep fascia of the forearm, TCL and the aponeurosis between the thenar and hypothenar muscles.16 A successful CTR usually requires division of all these structures. The first open CTR was reportedly performed by Herbert Galloway in 1924.17 Endoscopic CTR was first described by Okutsu et al in 1989.18 The flexor retinaculum protects the median nerve, prevents bowstringing of the flexor tendons and maximises grip strength. The TCL is the largest and strongest ligament of the wrist, enhancing grip strength and providing stability to the whole hand. In two cadaver studies, Garcia-Elias et al19 found that division of the TCL reduced stiffness of the global transverse carpal arch by a mean of 7.5% and Fisk20 showed a decrease in carpal concavity and widening of the carpal tunnel by a mean of 3 mm. In a biomechanical cadaver study, Fuss and Wagner21 also found widening of the carpal tunnel, loss of anatomical attachment of the thenar and hypothenar muscles and decreased strength of the hand. In order to reduce the described negative effects, Netscher22 recommended reconstruction of the TCL after open CTR. Based on several experimental and clinical studies, Altissimi23 also recommended TCL reconstruction, because the ability of a patient to return to work is directly related to post-operative weakness and the delay in recovery of grip strength, even though the endoscopic techniques have been developed to achieve a more rapid recovery. Several techniques of reconstruction have been reported in the literature. Seitz and Lall24 reconstructed the TCL by Z-lengthening in 56 patients. Compared with an isolated open release, grip strength returned to near normal earlier, with a mean improvement of 18%. Jakab, Ganos and Cook25 lengthened the ligament 6 mm to 7 mm in a stepwise fashion. In a review of 104 hands, 97 (93%) obtained complete relief of symptoms with no loss of grip strength. In a double-blinded study, Xu, Huang and Hou26 concluded that patients who underwent coronal Z-type TCL lengthening achieved better function and greater satisfaction than with conventional CTR. Duché and Trabelsi27 found that TCL reconstruction with a Canaletto implant (Eurymed,
30 27 24 21 18 15 12 9 6 3
Cylindrical grip strength (%)
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Function
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Group A Group B Group C
Pre-op 1
3
6
12 18 Duration (mths)
100 90 80 70 60 50 40 30 20 10
24
Group A Group B Group C
Pre-op 1
3
Fig. 8a
100 90 80 70 60 50 40 30 20 10
Group A Group B Group C
Pre-op 1
3
12 6 Duration (mths)
18
24
Fig. 8b
Pinch grip strength (%)
Lateral grip strength (%)
100 90 80 70 60 50 40 30 20 10
6 12 Duration (mths)
18
24
Fig. 8c
Group A Group B Group C
Pre-op 1
3
18 6 12 Duration (mths)
24
Fig. 8d
Graphs showing the parameters after three methods of carpal tunnel release (CTR), i.e. CTR with subneural TCL plasty (group A, n = 68), isolated open CTR (group B, n = 92) and endoscopic CTR (group C, n = 53). Mean functional status based on the Boston Carpal Tunnel Questionnaire; mean percentages of cylindrical grip strength compared with those recorded for the opposite hand; lateral grip strength and pinch grip strength.
Nîmes, France) achieved better results than open CTR. In a cadaver study, Pavlidis et al4 showed that TCL lengthening increases the capacity of the carpal tunnel by 31% to 44%, regardless of the surgical technique used. Although reconstruction of the TCL over the median nerve improves grip strength, it may compromise the decompression. In contrast to the other procedures, our TCL reconstruction creates a new carpal tunnel beneath the median nerve. Thus, the kinematics of the carpal tunnel can be restored without the risk of recurrent nerve entrapment. The abductor pollicis brevis is an important muscle innervated by the median nerve. However, in our study we did not test its strength in isolation, because its isolated function is obscured by a number of synergists of other thenar muscles. There is, however, a strong correlation between pinch strength and the strength of the muscle.28 Our study shows that reconstruction of the TCL beneath the median nerve gives better hand function than isolated open and endoscopic TCL division. All three methods
result in similar symptomatic improvement. The incidence of scar pain is lower after endoscopic surgery. Possibly, because of the absence of bowstringing of the flexor tendons, TCL reconstruction achieves a better appearance, even though endoscopic surgery is performed through small incisions. Overall, patients who underwent subneural reconstruction of the TCL had a higher mean Michigan Hand Outcome score than those who underwent isolated open and endoscopic CTR. Our consecutive assessments showed that patients who underwent reconstruction of the TCL had better subsequent hand function. However, their recovery of grip strength was slower, which may be due to our post-operative immobilisation of the wrist. Hand function and strength recovered within one to six months. Our retrospective study has limitations. Although the patients were randomly allocated, bias may have arisen owing to the involvement of three centres and several surgeons.
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Table III. Statistical analysis (t-test) between the groups p-value Gender Age Dominance Severity of symptoms Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 Functional status Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 Cylindrical grip strength Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 Lateral grip strength Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 Pinch grip strength Pre-op Month 1 Month 3 Month 6 Month 12 Month 18 Month 24 MHO score Pre-op Month 12 Month 24 Bowstring Pain Appearance
Groups A and B
Groups A and C
Groups B and C
0.053 0.133 0.105
0.205 0.107 0.126
0.113 0.462 0.113
0.084 0.425 0.206 0.264 0.336 0.418 0.267
0.204 0.230 0.674 0.777 0.381 0.402 0.423
0.457 0.719 0.739 0.773 0.520 0.254 0.329
0.114 0.001 0.001 0.001 0.003 0.001 0.015
0.612 0.079 0.030 0.026 0.031 0.001 0.001
0.082 0.018 0.045 0.231 0.452 0.519 0.248
0.905 0.004 0.001 0.001 0.015 0.001 0.002
0.490 0.001 0.001 0.009 0.032 0.001 0.001
0.273 0.219 0.169 0.367 0.451 0.266 0.347
0.352 0.033 0.255 0.427 0.250 0.336 0.754
0.477 0.011 0.374 0.126 0.293 0.521 0.329
0.087 0.007 0.786 0.352 0.224 0.078 0.128
0.266 0.341 0.525 0.004 0.012 0.001 0.006
0.753 0.563 0.094 0.008 0.032 0.016 0.025
0.182 0.022 0.007 0.269 0.531 0.756 0.392
0.478 0.002 0.001 0.004 0.803 0.001
0.216 0.012 0.001 0.020 0.001 0.001
0.321 0.006 0.001 4.84 0.001 0.044
Strength has added 6% at the dominant side MHO, Michigan Hand Outcome
Subneural reconstruction of the TCL offers an alternative to isolated open and endoscopic CTR and maximises hand strength by stabilising the transverse carpal arch. VOL. 97-B, No. 2, FEBRUARY 2015
Author contributions X. Zhang Contributed to study design, Approved the final manuscript. Y. Li: Study implementation. S. Wen: Study implementation. H. Zhu: Study implementation.
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X. ZHANG, Y. LI, S. WEN, H. ZHU, X. SHAO, Y. YU
X. Shao: Refinement of the study protocol. Y. Yu: Refinement of the study protocol.. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by G. Scott and first proof edited by A.C. Ross.
References 1. Rossignol M, Stock S, Patry L, Armstrong B. Carpal tunnel syndrome: what is attributable to work? The Montreal study. Occup Environ Med 1997;54:519–523. 2. Liong K, Lahiri A, Lee S, et al. Mid-motion deformation of median nerve during finger flexion: a new insight into the dynamic aetiology of carpal tunnel syndrome. Hand Surg 2013;18:193–202. 3. Yoshii Y, Ishii T, Tung WL, Sakai S, Amadio PC. Median nerve deformation and displacement in the carpal tunnel during finger motion. J Orthop Res 2013;31:1876– 1880. 4. Pavlidis L, Chalidis BE, Demiri E, Dimitriou CG. The effect of transverse carpal ligament lengthening on carpal tunnel volumetry: a comparison between four techniques. Ann Plast Surg 2010;65:480–484. 5. Dias JJ, Bhowal B, Wildin CJ, Thompson JR. Carpal tunnel decompression; is lengthening of the flexor retinaculum better than simple division? J Hand Surg Br 2004;29:271–276. 6. Mlakar M, Ramstrand N, Burger H, Vidmar G. Effect of custom-made and prefabricated orthoses on grip strength in persons with carpal tunnel syndrome. Prosthet Orthot Int 2013;38:193–198. 7. Kohanzadeh S, Herrera FA, Dobke M. Outcomes of open and endoscopic carpal tunnel release: a meta-analysis. Hand (N Y) 2012;7:247–251. 8. Ansari NN, Adelmanesh F, Naghdi S, Mousavi S. The relationship between symptoms, clinical tests and nerve conduction study findings in carpal tunnel syndrome. Electromyogr Clin Neurophysiol 2009;49:53–57. 9. Yayama T, Kobayashi S, Awara K, et al. Intraneural blood flow analysis during an intraoperative Phalen's test in carpal tunnel syndrome. J Orthop Res 2010;28:1022– 1025. 10. Szabo RM, Slater RR Jr, Farver TB, Stanton DB, Sharman WK. The value of diagnostic testing in carpal tunnel syndrome. J Hand Surg Am 1999;24:704–714. 11. Blair WF, Goetz DD, Ross MA, Steyers CM, Chang P. Carpal tunnel release with and without epineurotomy: a comparative prospective trial. J Hand Surg Am 1996;21:655–661. 12. Levine DW, Simmons BP, Koris MJ, et al. A self-administered questionnaire for the assessment of severity of symptoms and functional status in carpal tunnel syndrome. J Bone Joint Surg [Am] 1993;75-A:1585–1592.
13. Chung KC, Pillsbury MS, Walters MR, Hayward RA. Reliability and validity testing of the Michigan Hand Outcomes Questionnaire. J Hand Surg Am 1998;23:575– 587. 14. Uchiyama S, Yasutomi T, Momose T, et al. Carpal tunnel pressure measurement during two-portal endoscopic carpal tunnel release. Clin Biomech (Bristol, Avon) 2010;25:893–898. 15. Crosby CA, Wehbé MA, Mawr B. Hand strength: normative values. J Hand Surg Am 1994;19:665–670. 16. Tanabe T, Okutsu I. An anatomical study of the palmar ligamentous structures of the carpal canal. J Hand Surg Br 1997;22:754–757. 17. Amadio PC. The first carpal tunnel release? J Hand Surg Br 1995;20:40–41. 18. Okutsu I, Ninomiya S, Takatori Y, Ugawa Y. Endoscopic management of carpal tunnel syndrome. Arthroscopy 1989;5:11–18. 19. Garcia-Elias M, An KN, Cooney WP 3rd, Linscheid RL, Chao EY. Stability of the transverse carpal arch: an experimental study. J Hand Surg Am 1989;14(2Pt1):277– 282. 20. Fisk GR. The influence of the transverse carpal ligament (flexor retinaculum) on stability. Ann Chir Main 1984;3:297–299 (article in English, French). 21. Fuss FK, Wagner TF. Biomechanical alterations in the carpal arch and hand muscles after carpal tunnel release: a further approach toward understanding the function of the flexor retinaculum and the cause of postoperative grip weakness. Clin Anat 1996;9:100–108. 22. Netscher DT. The benefit of transverse carpal ligament reconstruction following open carpal tunnel release. Plast Reconstr Surg 2003;111:2020–2022. 23. Altissimi M. Critical Appraisal of Transverse Carpal Ligament Reconstruction. Theoretical, Experimental, and Clinical Considerations. Carpal Tunnel Syndrome. Springer Berlin Heidelberg, 2007;239–240. 24. Seitz WH, Lall A. Open carpal tunnel release with median neurolysis and Z-plasty reconstruction of the transverse carpal ligament. Curr Orthop Pract 2013;24:53–57. 25. Jakab E, Ganos D, Cook FW. Transverse carpal ligament reconstruction in surgery for carpal tunnel syndrome: a new technique. J Hand Surg Am 1991;16:202–206. 26. Xu L, Huang F, Hou C. Treatment for carpal tunnel syndrome by coronal Z-type lengthening of the transverse carpal ligament. J Pak Med Assoc 2011;61:1068–1071. 27. Duché R, Trabelsi A. The Canalettoimplant for reconstructing transverse carpal ligament in carpal tunnel surgery; surgical technique and cohort prospective study about 400 Canaletto cases versus 400 cases with open carpal tunnel surgery. Chir Main 2010;29:352–359. 28. Schreuders TA, Selles RW, Roebroeck ME, Stam HJ. Strength measurements of the intrinsic hand muscles: a review of the development and evaluation of the Rotterdam intrinsic hand myometer. J Hand Ther 2006;19:393–401.
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