Keywords Carpal tunnel syndrome - Carpal tunnel release - Pittsburgh Sleep Quality Index -
Boston Carpal Tunnel Syndrome Questionnaire
Introduction
Carpal tunnel syndrome (CTS), first described by Sir James Paget in 1854,[1 ] is the most common entrapment neuropathy of the upper extremity. This disease has
been reported to affect mostly women.[2 ] It is characterized by numbness, tingling, and pain in the median nerve distribution.[3 ]
[4 ] Pain and numbness in nighttime has also been reported as common symptoms of CTS.
Night waking with numbness due to wrist position is an important problem of CTS which
hinders the ability to sleep well.[3 ]
[5 ]
[6 ] Disrupted sleep is also common in patients with CTS, with approximately 80% of patients
with CTS having nighttime waking due to numbness.[7 ] Due to frequent nighttime awakening and fragmented sleep, CTS also increases daytime
sleepiness and dysfunction. Thus, relief of nighttime symptoms plays a key role in
the treatment of CTS. While most conservative treatments do not work well with CTS
with severe manifestations (e.g., nighttime symptoms), surgery is necessary. Carpal
tunnel release (CTR) has shown to improve sleep disturbance in patients with CTS;[8 ]
[9 ]
[10 ]
[11 ]
[12 ]
[13 ] however, the available evidence is limited, as the number of reported studies as
well as their sample sizes are small. Therefore, we performed this study in order
to investigate the impact of CTR on sleep quality and the symptoms and functions of
the hand in patients with CTS and poor sleep quality.
Methods
Study Design and Population
This was a prospective study from May 2019 to September 2020 at a tertiary referral
hospital in Ho Chi Minh city, Vietnam. The study was approved by an Independent Ethics
Committee before recruiting any patient. We consecutively recruited patients older
than 18 years of age with confirmed diagnosis of CTS who underwent CTR with existing
preoperative diagnoses of poor sleep quality. Exclusion criteria were as follows:
(1) comorbidities of other neurological diseases such as polyneuritis and brachial
plexus disorders, and (2) lost to follow-up at all scheduled visit after the surgery.
The diagnosis of CTS was in accordance with the clinical practice guideline approved
by the American Academy of Orthopaedic Surgeons.[14 ]
[15 ] Patients were diagnosed with poor sleep quality preoperatively when the global Pittsburgh
sleep quality index (PSQI) score was more than five. The indications of surgery for
patients with CTS included the denervation of the abductor pollicis brevis muscle,
sensory loss, or pain unresponsive to conservative treatments. Written informed consent
was obtained from all patients before enrollment.
Assessment and Follow-Up of Patients
Demographic, clinical data, PSQI, and the Boston carpal tunnel syndrome questionnaire
were used to assess the function and severity of the disease preoperatively. All patients
underwent median nerve decompression through a limited palmar incision by a single
experienced surgeon. Wrist splint and pharmacotherapy were used during 2 weeks after
surgery. Sleep quality and severity of symptoms were evaluated at 1, 3, and 12 months
postoperatively by the PSQI and Boston carpal tunnel syndrome questionnaire.
The PSQI is a self-rated questionnaire that can assess sleep quality and disturbances
over a 1-month period.[16 ] It consists of 19 individual items which generate the following seven components:
sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances,
use of sleeping medication, and daytime dysfunction. Each component is scored from
zero to three, with zero representing no problem and three representing the worst
sleep quality. The total score of these seven components yields the global PSQI score.
The higher the score, the worse sleep quality that the patient complains of. Since
all patients did not use pharmacological or medical support for sleeping problems,
all were given a score of zero for the sixth component (use of sleeping medication)
and this component was excluded from the analysis.
The Boston carpal tunnel syndrome questionnaire,[17 ] also called the Levine–Katz Questionnaire, is also a self-administered questionnaire
which assesses the severity of symptoms and functional status in patients with CTS.
It has 19 questions: 11 dealing with symptom and eight with function. Each question
is scored from one (the mildest) to five (the most severe). A higher score indicates
more severity of the patient's symptom and function.
Statistical Analysis
Patients' characteristics and study outcomes (PSQI and Boston scores) were summarized
by counts and percentages for categorical variables, and median and interquartile
range (IQR) for continuous variables. The longitudinal measurements of the outcomes
were presented graphically for males and females. We compared the differences of the
scores between each time-point before and after CTR using Wilcoxon signed rank test.
Correlation between PSQI and Boston symptom score and Boston function score were analyzed
by Spearman's correlation coefficients. All tests were two-sided and statistical significance
was defined when p -value was < 0.05. All analyses were performed using the statistical software R version
3.6.3 (R Foundation for Statistical Computing, Vienna, Austria).
Results
A total of 33 patients were included in the study with females predominating (27 cases,
82%) and median age of 51 years (range: 33–71). Median duration of confirmed CTS before
undergoing the surgery was 12 months (range: 5–36), whereas median duration of having
sleep disorder was 6 months (range: 2–12). There was no patient with hypothyroidism
or rheumatoid arthritis. All patients had received conservative treatment with the
median preoperative duration being 8 months (range: 3–18). Eight patients (24%) underwent
CTR in both hands ([Table 1 ]).
Table 1
Patients' characteristics
All patients(n = 33)
Sex female, n (%)
27 (82)
Age (years), median (IQR)
51 (45–57)
Duration of CTS before surgery (months), median (IQR)
12 (12–15)
Duration of sleep disorder before surgery (months), median (IQR)
6 (5–7)
Receiving conservative treatment previously, median (IQR)
33 (100)
Duration of conservative treatment before surgery (months), median (IQR)
8 (6–10)
Hypothyroidism, n (%)
0 (0)
Rheumatoid arthritis, n (%)
0 (0)
Hand undergoing surgery, n (%)
Right hand
14 (43)
Left hand
11 (33)
Both hands
8 (24)
Abbreviations: CTS, carpal tunnel syndrome; IQR, interquartile range.
Median global PSQI score was 12 (range: 8–16) before surgery and decreased to 9 (range:
6–15) at 1 month, 7 (range: 5–10) at 3 months, and 1 (range: 0–9) at 12 months postoperatively,
with significant differences ([Table 2 ], [Fig. 1 ]). The analysis of each PSQI component also showed significant improvement in all
components after surgery ([Table 2 ]). With regard to the Boston symptom and function scores, the results were similar,
with a significant improvement in the hand symptom and function scores from before
to after surgery ([Table 2 ], [Fig. 1 ]). The improvement of these scores were similar in males and females ([Fig. 1 ]).
Fig. 1 Pittsburgh sleep quality index and Boston test scores over time. In each plot, scores
are presented by time-points before and after surgery 1, 3, and 12 months and are
colored separately for males and females. The line inside each box is the median,
and the upper and lower margins of each box represent the interquartile range. The
points and lines represent the actual scores of each individual patient at each time-point.
Table 2
Outcomes assessment
Before surgery
1 month
p
0-1
3 months
p
1,2
12 months
p
2,3
Sleep quality
2 (2–3)
2 (2–2)
< 0.001
2 (1–2)
< 0.001
0 (0–1)
< 0.001
Sleep latency
2 (2–3)
2 (2–3)
0.180
2 (1–2)
< 0.001
0 (0–1)
< 0.001
Sleep duration
2 (2–3)
1 (1–2)
< 0.001
1 (1–1)
< 0.001
1 (1–1)
0.037
Habitual sleep efficiency
2 (2–3)
1 (1–2)
< 0.001
0 (0–1)
< 0.001
0 (0–0)
0.011
Sleep disturbances
1 (1–1)
1 (1–1)
−
1 (1–1)
−
0 (0–0)
< 0.001
Daytime dysfunction
3 (2–3)
2 (2–3)
0.066
2 (1–2)
< 0.001
0 (0–0)
< 0.001
PSQI global score
12 (11–15)
9 (8–12)
< 0.001
7 (5–9)
< 0.001
1 (1–2)
< 0.001
Boston symptom score
33 (29–40)
14 (14–19)
< 0.001
13 (13–15)
< 0.001
11 (11–11)
< 0.001
Boston function score
23 (18–26)
11 (9–13)
< 0.001
9 (8–10)
< 0.001
8 (8–8)
0.170
Abbreviations: IQR, interquartile range; PSQI, Pittsburgh sleep quality index.
Note: Summary statistics are median (IQR). p
0-1 is for testing change from before surgery to 1 month. p
1,2 is for testing change from 1 to 3 months. p
2,3 is for testing change from 3 to 12 months. All p -values are based on Wilcoxon signed rank test.
The PSQI global scores had a significant and highly positive correlation with the
Boston symptom and function scores. The correlation was consistent from before to
after surgery, with the Spearman's correlation coefficients being > 0.60 in all analyses
([Fig. 2 ]).
Fig. 2 Correlation between Pittsburgh sleep quality index (PSQI) and Boston test scores
The plots represent the correlation between PSQI score and Boston symptom score (in
the left column), and Boston function score (in the right column), at the four time-points
(before surgery, after surgery 1, 3, and 12 months, from top to bottom, respectively).
Each gray point represents for each patient. Spearman's correlation coefficient and
p -value are shown in the bottom right corner of each plot.
Discussion
This study shows consistent improvements of sleep quality as well as the symptoms
and functions of the hand at 1 to 12 months after CTR, according to the PSQI and Boston
symptom and function scores. The study also demonstrates that sleep quality highly
correlates with the hand symptom and function scores. As good sleep quality is important
and can reduce the risk of stress, depression, hypertension, overweight and obesity,
it is important for patients to undergo CTR when having indication.
Sleep symptoms are frequent in patients with CTS and cause a huge impact on their
quality of life, but they have just got more attention since several years ago. The
seriousness of sleep disorder is thought to associate with the grade of nerve entrapment.[5 ] This is somehow proved in our study by the strong positive correlation between the
PSQI score and the Boston symptom and function scores: the more severe symptom is
associated with the worse sleep quality. Although both questionnaires are subjective,
the consistent results of these correlations at multiple time-points before and after
surgery would minimize the potential subjective bias. In addition, other studies also
reported the significant correlation between CTS symptom and functional severity with
sleep quality,[6 ]
[12 ] which consolidate the evidence of the association between CTS symptoms and sleep
disturbance. Therefore, handling the symptoms is essential in order to solve the sleep
problem of patients with CTS. In patients with long time of having CTS, especially
those with poor sleep quality due to CTS, most conservative treatments do not work
well and surgery is the only choice. Indeed, CTR has shown its effectiveness in CTS
by the significant improvement in the hand's symptoms and functions as well as sleep
quality.[8 ]
[9 ]
[10 ]
[11 ]
[12 ]
[13 ]
[18 ] In our study, the early improvements are more marked for the symptoms and functions
of the hand, whereas the sleep quality improved more slowly. However, our study and
others have a relatively short follow-up period (less than 1 year), so long-term outcomes
of patients are still lacking, as in our results, some patients tend to be worse from
3 to 12 months after the surgery, with respect to both the PSQI and Boston symptom
and function scores.
Limitations of the study included lack of a control group without surgery and potential
selection bias due to a single-centre design with single surgeon's practice. A comparable
multicenter study would confirm and generalize the results better. However, a control
group with similar disease severity is hard to get because surgery is indicated for
patients with pain unresponsive to conservative treatment. Second, recall bias, which
is inherent in all questionnaires, maybe present in this study. However, the consistent
improvement of the scores via assessing all patients several times before and after
surgery could minimize this potential bias. Third, sleep quality was not evaluated
using polysomnography. Therefore, obstructive sleep apnea, which was reported to have
higher frequency of CTS,[19 ] could not be excluded in this study.
In conclusion, surgical decompression significantly improves sleep quality and the
symptom and function of the hand in patients with CTS and poor sleep quality. These
improvements start right after the surgery and remain until 12 months. The study also
confirms that the PSQI and Boston symptom and function questionnaires are applicable
instruments to quantify the results after CTR. More studies with long-term follow-up
are needed, as there is lack of long-term results of the surgery in the treatment
of CTS.
