Nonoperative carpal tunnel syndrome treatment

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A. Lee Osterman, MD

^a,b

, Marc Whitman, PT

^c,1

, Linda Della Porta, OTR, CHT

^c,2,

*

aPhiladelphia Hand Center, 834 Chestnut street, Philadelphia, PA, USA

bDepartment of Orthopedic and Hand Surgery, Thomas Jeﬀerson University Hospital, USA

cRecipient of the Evelyn JMackin Hand Therapy Fellowship, 834 Chestnut Street, Philadelphia, PA, USA

Carpal tunnel syndrome (CTS) has been cited as the most common of the upper extremity compression neuropathies [1–3]. A recent study examined the prevalence osf CTS in a Swedish general population. The authors found, in a population of 170,000, self-reported sensory changes and/or pain in the median nerve (MN) distribution in 14.4%, clinical and electrophysiologically con- ﬁrmed CTS in 2.7% [4]. Among workers, the inci- dence of CTS, based on claim data, was reported as 24.5 per 10,000 full-time employees in Washing- ton State [5]. In addition, the Bureau of Labor Statistics (BLS) reported 1,702,500 work-related injuries involving time away from work, and of those 27,900 cases or 1.6% were CTS [6].

In terms of cost and time away from work, CTS has resulted in lost revenue for the employer and employee. The BLS considers median days away from work a key indicator as to the severity of occupational injury. In 1999, CTS required the highest time away at 27 days, followed by fracture (20 days) and amputations (18 days) [7]. In Wash- ington State, there were 27,148 claims ﬁled for CTS at an average cost of $12,627 per claim between 1992 and 1998 [5]. This resulted in more than $300,000,000 for the management of CTS and may not include other costs such as litigation, lost productivity, lost wages, or retraining.

As CTS continues to manifest itself as a signiﬁ- cant economic and debilitating entity, it will be more important to research and develop treatment approaches. We believe that nonoperative treatment is a viable option for the management of CTS. The following discussion will explore the various treatment options presented in the literature and the rationale behind their use.

Why choose nonsurgical treatments? There are several reasons:

1. Conservative management can cost less than surgical management. In California (1993), the average cost of surgical intervention was

$20,925, as compared with $5,246 for nonoperative intervention [8].

2. Various nonsurgical treatments for CTS have been shown to ameliorate symptoms in 13–

92% of patients [3,9–16]. These studies docu- ment that conservative management is eﬀective.

3. There is a population of CTS patients that is appropriate for conservative treatment [17,18]. Patients with carpal tunnel symptoms can generally be categorized based on chron- icity and severity of signs and symptoms.

[1,19,20]. Those patients with underlying systemic disease or severe changes indicative of MN compromise need surgical decompres- sion or further medical management [18,21].

But as recommended by several authors [10,11,13,14,22], conservative treatment is indicated for mild to moderate symptoms with early intervention generally more predictive of satisfactory outcomes.

4. It has been speculated [16] that many patients with the signs and symptoms of CTS are now

* Corresponding author.

E-mail address: [email protected] (L. Della Porta).

1Present address: P.O. Box 112192, Anchorage, AK 99511-2192

2Present address: 56 Parkton Road #1, Jamaica Plain, MA 02130

PII: S 0 7 4 9 - 0 7 1 2 ( 0 2 ) 0 0 0 2 3 - 9

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seeking treatment earlier caused by the improved access to information by various media sources. If this is the case, then nonsurgical intervention will continue to be instru- mental in treatment of this condition.

5. Finally, as with any surgery, there are risks associated with the procedure to release the carpal tunnel. These include infection, stiff- ness, reﬂex sympathetic dystrophy, and nerve or tendon injury [19], which makes nonoperative management a more appealing ﬁrst line of treatment.

We are not advocating that surgical intervention for CTS is unncessary or warranted, but, potentially, surgery may be avoided and overall cost and time away from work may be reduced through the use of nonoperative treatment strategies if applied consistently and early in the course of treatment (see Box 1).

Overview

CTS generally is considered a compressive neuropathy of the MN as it courses through the carpal

tunnel of the wrist. Currently, there is a debate regarding whether ischemia or mechanical forces exerts the greatest impact on changes to the MN [17,19,22–26]. Controversy also exists about the role of inflammation. Although tissue studies do not support inflammation as a precursor to CTS [27,28], strategies to ‘‘reduce inflammation’’ have been used with some success [29,30]. CTS is regarded as a multifaceted syndrome, and causal- ity is largely unknown. It has been associated, however, with various conditions that can pre- dispose individuals to its development. These conditions are as follows: 1) acute trauma, 2) endocrine disorders, 3) inflammatory arthritis, 4) chronic renal failure, 5) pregnancy, 6) mass lesions within the carpal canal, 7) occupational/

recreational factors, 8) lifestyle, 9) traction injury, and 10) double crush [1,31–33]. The development of this neuropathy can also occur for seemingly no reason at all and is thus labeled ‘‘idiopathic carpal tunnel syndrome.’’

Treatment

The first course of treatment for CTS generally consists of prescribed medication consisting of nonsteroidal anti-inflammatory drugs (NSAIDs) and/or steroids that can be delivered orally or by injection. The action of these medications is to inhibit the chemical mediators of inflammation in response to injury. By limiting the inflammatory response, they also suppress pain by desensitizing nociceptors to these same chemicals [34]. The effectiveness of NSAIDs versus steroids for treatment of CTS was examined in a 1998 study. In a 4-week trial evaluating effect of medication as the sole treatment short-term, low-dose oral steroids were more effective than NSAIDs, diuretics, and placebo [35]. This was supported in another study, which also found low-dose, short-term oral steroids more effective than placebo only. This trial period was 8 weeks, however, and demonstrated that the initial improvement provided by the steroid was temporary with a return in symptoms [36]. Oral steroids seem to show more promise in the short-term management of CTS than NSAIDs but are associated with negative side-effects if used for long periods.

Local steroid injection into the carpal canal is an option to avoid the systemic actions of oral steroids. The injectable steroid of choice is water- soluble and can be combined with an anesthetic to reduce injection discomfort. A study examining Box 1 Current nonoperative

treatment Medicinal

• NSAIDs

• Steroids Injectible Oral

• Pyridoxine (B6) Modalities

• Ultrasound

• Iontophoresis Splinting

Activity modification

• Ergonomic intervention

• Avocational assessment Exercise

• Tendon gliding

• Nerve gliding

• General conditioning Yoga

Stretching

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injections [12] found long-term relief of symptoms (‡1 year) in only 24% of subjects. An additional 27% responded initially but then had a reoccur- rence of symptoms within 1 year. Various other studies have reported success rates from 13% to 92% utilizing injections alone or combined with splinting [10,14,16]. Success rates were deﬁned as lasting improvement in symptoms 11–18 months in duration. Response to an injection can also cor- relate and predict the response to surgical release [13]. This is particularly true when there are con- founding conditions, such as double crush syndrome [32], diabetes, and discrepancies on the cervical spine exam. Complications and risks associated with injection of the carpal canal include tendon rupture, nerve injuries, pain, transient gly- cemic elevation in diabetics, skin atrophy, and depigmentation.

Controversy still exists regarding the role of pyridoxine (Vitamin B6) as a component in the treatment of CTS [37–40]. The current literature does not clearly support or detract from the use of vitamin B6. Therefore, if utilized, it should be in conjunction with other treatments (Box 1).

Splinting

Immobilization of the wrist through splinting is a component of nonoperative treatment. Individu- als are instructed to wear splints while sleeping because that is when symptoms tend to be most pronounced. In addition, it is more diﬃcult to maintain the wrist in a neutral position at this time. During wakening hours, individuals can be instructed to monitor wrist position with activity and to maintain the wrist in a neutral alignment, avoiding ulnar deviation.

Carpal tunnel pressures have been studied with ﬂexion and extension to determine the position of the wrist that results in the lowest carpal canal pressures. It was reported that 2þ/9of extension and 2þ/6of ulnar deviation is the position with the lowest carpal canal pressure. Immobiliza- tion of the wrist closest to neutral was recommended [41]. Symptom relief at neutral and at 20 of wrist extension have been compared.

Results indicated that symptom relief was found to be greater at neutral than with 20 degrees of wrist extension [42]. With immobilization of the wrist, the angle of the splint should be carefully evaluated, as even small diﬀerences can aﬀect carpal canal pressures and symptom relief. Fre- quently, prefabricated splints position the wrist

at 20–30of extension (Fig. 1). Ideally, a thermo- plastic splint should be custom-ﬁt to ensure that the wrist is at a neutral angle (Fig. 2). It has been reported that individuals will experience a decrease in symptoms after wearing a splint for 2 weeks [42].

Optimal results with splints were obtained if applied within the ﬁrst 3 months of onset [43].

But a 2-week trial is worthwhile regardless of how long the individual has been experiencing symptoms [42]. The effect of lumbrical incursion with finger position has been studied. It was deter- mined that increased finger flexion increases carpal canal pressures. Therefore, it was concluded that finger motion as well as wrist position plays a role in carpal canal pressure [44]. A study of cadaveric dissections confirmed that the lumbrical muscles originate distal to the carpal canal with the fingers extended. With fingers flexed, lumbrical muscles were found within the carpal canal. It was suggested that the lumbricals can contribute to compression within the carpal tunnel [45]. Because increased finger flexion as well as wrist position play a role in carpal canal pressures, a metacarpal block may be a consideration if symptoms do not subside with a standard wrist splint.

Fig. 1. Commercially available splint.

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Therapeutic modalities

Therapeutic ultrasound is a modality that pro- duces acoustical high-frequency vibrations with both thermal and nonthermal effects [46]. It has been observed, ‘‘The literature suggest[s] that low intensity pulsed ultrasound is the most appropriate to promote healing of open wounds, to resolve acute and subacute inflammation, and to enhance repair in tendon, nerve and bone’’ [47]. With CTS, flexor tendons may be inflamed. If ultrasound is used, pulsed or nonthermal mode would be the most appropriate as continuous or thermal mode may irritate inflamed tendons.

Recently, the eﬀects of ultrasound for the treatment of mild to moderate idiopathic CTS were studied. Twenty treatments of pulsed ultrasound were applied to the area over the carpal tunnel.

Results suggested satisfying short- to medium- term eﬀects. Individuals receiving ultrasound treatments experienced reduced symptoms and improved nerve conduction compared with results in a placebo control group [48]. This study utilized ultrasound as the sole treatment. Our opinion, however, is that if ultrasound is used for carpal tunnel treatment, it should be in conjunction with

other conservative measures. It would also be ben- eﬁcial to study the eﬀects of fewer ultrasound treatments as 20 treatments may be costly.

Iontophoresis is an electrical modality used to deliver medication in an ion form with the objective of delivering a higher local concentration, minimizing systemic concentration [49]. In a study by Banta, a standard treatment protocol was utilized using wrist splinting, NSAIDs, and iontophoresis with dexamethasone sodium phosphate [9]. The study revealed a success rate comparable with splinting plus injection of dexamethasone into the carpal tunnel space. It should be noted that the study had several shortcomings: a small sample size, lack of randomization and blinding, and no use of a sham iontophoresis group. In those individuals that are unable to tolerate steroid injections into the carpal canal, however, the use of iontophoresis may be an option.

Ergonomic factors

Pressure over the carpal canal [23], wrist positioning [41–43], low temperatures [50], vibration [51,52], and high force with high repetition [30]

have been cited as occupationally related risk factors in the development of CTS. Nonoccupational risk factors such as diabetes, rheumatoid arthritis, thyroid disease, and obesity have also been cited as risks [50,53]. Weight and body mass have been cor- related with slowing of sensory conduction of the median nerve [53]. It was suggested that individual characteristics, not job-related factors, were primary determinants of CTS. The development of carpal tunnel syndrome is multifactorial, therefore controversy remains regarding the primary inﬂu- encing and etiologic factors [54].

Despite this controversy regarding primary influencing factors, it may be beneficial to address individuals’ occupational and nonoccupational risk factors in order to maximize the effectiveness of conservative treatment. Though ergonomic measures have not been shown to influence the development of CTS, they have been useful in the conservative management of those patients with established mild CTS.

Mechanical stress or direct pressure over the carpal canal has been shown to increase carpal canal pressures [23]. Wrist positioning with tool use can be modiﬁed when indicated. If a keyboard or tool is positioned incorrectly, direct pressure may be placed over the carpal canal, causing an increase in carpal canal pressures. Rounding and padding edges of workstations can be helpful.

Fig. 2. Custom-made splint by hand therapist.

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Positioning the wrist closest to a neutral alignment helps to achieve the lowest possible carpal canal pressure [41–43]; therefore, this neutral wrist alignment should be maintained with work and avocational activities. With the increasing use of computers at home, it is insuﬃcient to consider keyboard positioning for work needs only. Indi- viduals should be encouraged to apply ergonomic principles with all other daily activities. Ulnar deviation in excess of 20 has been associated with increased carpal tunnel pressures [41]. Ergo- nomic tools that are designed with bent handles or adaptations can decrease ulnar deviation. An ergonomic split keyboard maintains the wrist as straight, decreasing wrist deviation. But because an item is labeled ergonomic does not mean that it is the most appropriate. Items should be carefully evaluated and basic principles applied. An ergonomic keyboard will not be as eﬀective if it is placed at a level where the individual is unable to maintain the wrist in neutral alignment. In a recent study, it was found that in many partici- pants, carpal tunnel pressures measured during mouse use were greater than pressures known to alter nerve function and structure. Although not clinically demonstrated, authors’ recommenda- tions include minimizing wrist extension, prolonged mouse dragging, and performing other tasks with the mousing hand [55].

It was reported by Silverstein that high force combined with high repetitiveness increases the risk more than 5·that of either factor alone [30].

Strategies to decrease repetitiveness may include alternating repetitive with nonrepetitive work activity, stretch breaks, or job rotation. In order to change force requirements, the tool itself may need to be changed. Whenever possible, educate the individual to avoid overuse of ﬂexors or exerting more muscle force than is required. Bio- feedback can be helpful in increasing an individual’s awareness of hand postures. In a study comparing the eﬀects of biofeedback with CTS, individuals reported that this feedback was helpful in improving awareness. There was no direct objective evidence, however, that biofeedback was helpful in reducing the symptoms of CTS [59]. There is a correlation between carpal tunnel syndrome and prolonged exposure to environmental conditions such as vibration [51,56] and/

or cold temperature exposure [50]. Work gloves may be helpful but need to be carefully evaluated.

An individual may grip more forcefully secondary to a decrease in sensory feedback. When possible, modify the tool to dampen vibration. Reduction

of exposure to environmental factors through job rotation or elimination of aggravating factor may be necessary.

Exercises

An evaluation of upper extremity musculature and cervical screen should be completed prior to prescribing exercises or stretches for CTS. A proximal weakness may be contributing to overuse of distal musculature. An individual can also present with muscle imbalances secondary to overuse of flexors. In cases where extensor weaknesses is noted, stretches of flexor musculature and strengthening of extensors would be the most appropriate. Repetitive gripping exercises with grip tools or balls can contribute to further inflammation of flexor musculature and therefore should be avoided. An assessment of daily activities or components of work is helpful in determining the most appropriate stretches or exercises for an individual. Stretch breaks from repetitive activities should be encouraged. In a recent study, significant decreases in carpal tunnel pressures were noted following 1 minute of hand and wrist exercises. Brief intermittent wrist and hand exercises were recommended to reduce intratunnel pressure [57]. Based on these findings, specific exercises were developed for CTS [29,57].

Tendon gliding exercises and median nerve gliding exercises

The effectiveness of nerve and tendon gliding exercises for the conservative treatment of CTS has been studied (Fig. 3 and Fig. 4). The study indicated that 43% of those who performed the exercises did not undergo surgery, whereas 71.2% of those who did not perform the exercises underwent surgery. The experimental and control groups both received traditional conservative treatment with splinting, nonsteroidal anti-inflammatory medication, and steroid injections. The difference was that the experimental group also performed tendon and nerve gliding exercises as developed by Totten and Hunter [15,58]. The authors of this study postulated that guiding the wrist and fingers through this program of nerve and tendon gliding exercises would help to maximize MN excursion in the carpal tunnel and excursion of the flexor tendons relative to one another. They proposed that a ‘‘ milking’’ effect would promote venous return and decrease the pressure inside the perineurium [15,58]. Further

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Fig. 3. (A–D) Tendon gliding exercises. (FromTotten PA, Hunter JM. Therapeutic techniques to enhance nerve gliding in the thoracic outlet and carpal tunnel syndrome. Hand Clin 1991;7(3):505)

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Fig. 4. (A–E) Wrist level median nerve gliding exercises. (FromTotten PA, Hunter JM. Therapeutic techniques to enhance nerve gliding in the thoracic outlet and carpal tunnel syndrome. Hand Clin 1991;7(3):505.)

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research is needed to evaluate the most eﬀective exercises and nerve gliding techniques for CTS.

Brachial plexus gliding program

The median nerve has been shown to move within the carpal tunnel and the upper extremity with various positions. McLellan and Swash demonstrated movement of the MN longitudinally in the upper extremity, depending on joint position [60]. They also demonstrated longitudinal movement of the MN with proximal joint motion of the shoulder and elbow. It was theorized that this longitudinal sliding is necessary to minimize local stretching and to prevent entrapment along the course of the nerve as the limb moves.

In work by Butler, this longitudinal movement of the peripheral nervous system is recognized.

Butler describes selective tensioning of the upper limb for treatment of neural entrapment. He has elaborated on Elveys brachial plexus tension test, with median ulnar and radial nerve bias [61,62].

A brachial plexus gliding program has also been described to facilitate nerve gliding from proximal to distal. With this program, the individual attempts to move to the point of tension, not pain,

to avoid aggravating symptoms. As symptoms decrease, the individual can progressively perform the remaining movements of the sequence [62].

Double crush syndrome, originally described by Upton and McComas [63], refers to the coexistence of dual lesions along the course of a nerve.

They proposed that a more proximal lesion would lessen the ability of the nerve to withstand a more distal compressive force. The coexistence of CTS with cervical radiculopathy has been reported in the literature [32,64]. If the individual being treated for CTS presents with a more proximal lesion, performing wrist level median nerve gliding exercises only may be insuﬃcient. Proximal shoulder or cervical issues should be evaluated.

The effects of performing brachial plexus nerve glides have not been studied for the treatment of CTS. Further research on proximal as well as distal stretches, nerve glides, or exercises would be beneficial to determine potential benefit in the treatment of CTS.

Yoga

Recently, a preliminary study compared effects of a yoga-based regimen in the treatment of CTS [65]. Subjects assigned to the yoga group performed 11 yoga postures along with relaxation twice weekly for 1–1.5 hour sessions. Subjects in the yoga groups demonstrated improvements in grip strength, pain reduction, and improvements with Phalen’s sign. Significant differences were not demonstrated with Tinel’s sign, sleep disturb- ance, or in motor and sensory conduction time.

This study demonstrated improvements with the use of yoga postures; however, several limitations exist. In addition to small sample size, medication use, and splint angle for controls were not recorded.

It is important to realize that specific postures were utilized; therefore, it is difficult to generalize that all of yoga may be effective in improving carpal tunnel symptoms. There are many different schools of yoga, and varieties of teaching. Each type of yoga emphasizes different postures, relaxation, and breathing techniques. Hatha yoga is the branch of yoga involved with movement. There are forms of yoga that do not involve movement and emphasize relaxation or attainment of spiri- tual goals. The yoga utilized in this study is based on movement or hatha yoga along with relaxation techniques. The exercises utilized emphasize upper extremity movements and stretches, both proximal and distal. In our opinion, this study reinforces the Fig. 4 (continued)

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importance of upper extremity stretching and attention to proximal upper extremity status as well as wrist level stretches. Individuals who are able to incorporate yoga into their life may ﬁnd this form of exercise helpful. Further research is needed to investigate upper extremity stretches or yoga postures that would be most beneﬁcial in the treatment of CTS.

Roslyn Evans’ approach

Roslyn Evans’ nonoperative approach to CTS includes splinting and activity modiﬁcation. Exer- cise putty and hand grippers are not recommended as they may contribute to increased pressure on the MN from lumbrical incursion. Tendon gliding exercises and median nerve gliding are not included as a component of nonoperative treatment [66].

Speciﬁc splinting guidelines are suggested [66]:

1. Splinting the wrist in 2of wrist ﬂexion, 3of ulnar deviation.

2. For individuals with positive lumbrical incursion and flexor tenosynovitis, and with patients who inadvertently flex fingers against the splint in an attempt to relieve symptoms, a metacarpal block is suggested. Recommen- dation is to splint the wrist in 2of wrist flexion, 3of ulnar deviation, MP joints at 0–20 of flexion, and IP joints free.

3. For individuals with severe symptoms and pain, a full resting pan splint is recommended.

Positioning recommendation is for wrist in 2of wrist ﬂexion, 3of ulnar deviation, MP joints in ﬂexion, IP joints in extension, and to rest carpal metacarpal (CMC) joint and thumb in neutral to slight extension.

Summary

Many factors influence the development of CTS; therefore, nonoperative treatment should not be limited to only one intervention. Nonoper- ative treatment is most effective in the early stages, prior to irreparable damage to the nerve. Early intervention combined with a comprehensive treatment plan can help improve effectiveness of treatment during this phase. We do not endorse any one particular conservative treatment/program as the solution for CTS, but our purpose is to explore potential options. Further study is needed to determine the most beneficial and cost-effective treatments.

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