Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: An exploratory, prospective, observational pilot study.

BACKGROUND: Cervical radiculopathy is a relatively common and disabling condition involving local pain in the neck region and pain that radiates into the upper limb. Recent data suggest that cervical traction may effectively reduce disability and pain, with a dose-response relationship. The main aim of this study was therefore to evaluate the mid-term effect of an intensive cervical traction protocol for patients with cervical radiculopathy on disability, and to compare the effects with those reported by non-intensive protocols in the literature.
METHODS: We conducted a prospective open observational study of 36 patients referred by their general practitioner for symptoms suggestive of cervical radiculopathy. All patients underwent the same treatment: a 30-minute cervical traction protocol, twice a day, for five consecutive days. The main objective was the evaluation of disability at 3 months. We evaluated at baseline (D1), the end of the protocol (D5) and at mid-term (M3) disability, cervical pain, radiating pain, pain on motor imagery, presence of neuropathic pain and medication consumption. The primary outcome was the proportion of patients for whom the Neck Disability Index improved by more than the minimum clinically important difference of 7 points by M3.
RESULTS: Thirty-six patients were included in this study. The Neck Disability Index improved by more than the minimum clinically important difference in 48.3% at M3. Mean Neck Disability Index (p < .001), mean cervical VAS (p < .001), mean radiating VAS (p < .001), and mean VAS for imagined lateral flexion and rotation (p < .002) improved significantly from D1 to D5 and from D1 to M3. Consumption of medication reduced at each time point. The proportion of patients with neuropathic pain reduced from 61.1% at D1 to 33.3% at D5 and 48.3% at M3.
CONCLUSION: Disability reduced by more than the minimum clinically important difference in almost half of the participants following the intensive traction protocol. These results are encouraging and suggest that this complex condition can be treated with relatively simple methods.

Introduction

Cervical radiculopathy is a relatively common and disabling condition [1] involving local pain in the neck region and pain that radiates into the upper limb. It is usually caused by a disc herniation or another space-occupying lesion that causes impingement and/or inflammation of the cervical nerve root [1, 2]. The prevalence of cervical radiculopathy is reported to be 3.5 per 1000 people [3], and the annual incidence varies from 83 cases to 210 cases per 100,000 people, with a peak from 50 to 59 years [4, 5]. The diagnosis may be confirmed by magnetic resonance imaging, electrophysiological testing (e.g. nerve conduction velocity tests or electromyography) or clinical examination (neck pain with referred pain to the arm, upper extremity paresthesia or numbness and signs of nerve root compression) [3].

A review of the natural history, clinical course, and prognostic factors of symptomatic cervical disc herniations with radiculopathy found that substantial improvements tend to occur within the first 4 to 6 months after onset [6]. Time to complete recovery ranges from 2 to 3 years [6], therefore this condition is associated with high costs due to repeated or prolonged sick leave, multiple evaluations (such as imaging) and multiple treatments, (including physiotherapy, surgery and medication) [7].

Treatment approaches are varied but the main aim of current treatments is to reduce pain and disability in the short-term, as well as to prevent recurrence in the long-term [6, 8]. Low quality evidence suggests that surgery may provide faster pain relief than physiotherapy or hard collar immobilization in patients with cervical radiculopathy or myelopathy [9]; but there is little or no difference in the long-term [9]. Conservative treatments involve strengthening, stretching, manual therapy, massage, medication and traction [10]. Cervical traction induces a separation of the vertebral bodies, movement of the facet joints, expansion of the intervertebral foramen, and stretching of soft tissues [3, 11]. A recent study found no difference between manual cervical traction and manual therapy and a combination of these techniques on pain, disability and cervical mobility [12], however a meta-analysis found a dose-response relationship of traction on these outcomes [3]. Romeo et al (2018) conducted a review and meta-analysis of five studies that compared the effects of traction with another treatment on pain and disability in adults with cervical radiculopathy [3] (Table 3). The meta-analysis found that studies that included more sessions and longer traction times resulted in better pain and disability outcomes.

Table 3

Comparison of protocol conditions across studies.

Study	N =	Lost to follow up	Number of sessions	Duration of the protocol (in weeks)	Mean no. sessions per week	Duration of the traction session (in minutes)	Intensity of the traction (in kilograms)
Jellad et al. (2009)	39	0	12	4	3	25+25	5 to 12kg
Moustafa et Diab (2014)	216	27	12	4	3	20	9,1 to 15,9kg
Fritz et al. (2014)	86	6mo = 22	10	4	2,5	15	3,6 to 9,1kg
		12mo = 32
Aydin et Yazicioglu (2012)	27	No data	15	3	5	20	5 to 20kg
Young et al. (2009)	81	8	7	4	1,75	15	9,1 to 15,9kg
Afzal et Al. (2019)	40	1	9	3	3	10	10 to 15% of body weight
Results	36	7 (including 3 for surgery)	10	1	10	30	5 to 10% of body weight, under 12kg

Thus, according to the literature, cervical traction appears to reduce pain and disability in cervical radiculopathy [3]. Furthermore, this treatment is low cost. In order to further investigate the apparent dose-response relationship found by Romeo et al., we wished evaluate the impact of an intensive traction program provided over a short period of time in patients with cervical radiculopathy. Our working hypothesis was that a more intensive protocol (ten 30-minute traction sessions provided over 5 days with massage) could shorten the recovery time and reduce the risk of chronicity, accelerate return to work and reduce the overall costs associated with cervical radiculopathy. The main aim of this study was therefore to evaluate the mid-term effect of an intensive cervical traction protocol for patients with cervical radiculopathy on disability, and to compare these effects with data from non-intensive protocols in the literature.

Method

Details of study design

We conducted a single center (Departmental Hospital Center—La Roche sur Yon site (Vendée, France), prospective, observational study that tested an intensive cervical traction protocol (see below for details). All patients received the same treatment.

Population

Patients were referred to our rheumatology department for assessment and treatment of cervical radiculopathy by their general practitioner. On admission, a clinical examination was performed by a rheumatologist who diagnosed cervical radiculopathy if the patient had pain radiating to the arm with motor and/or sensory dysfunction. These criteria were also used as study selection criteria by Romeo et al. for their meta-analysis. Symptoms reduced in six patients before beginning the traction protocol and the rheumatologist did not diagnose cervical radiculopathy (i.e. neck pain no longer radiated into the arm and there was no motor or sensory dysfunction), therefore they were not enrolled in the rehabilitation program. All other patients were enrolled in a rehabilitation program that included cervical traction.

Inclusion and non inclusion criteria

Patients over 18 years of age, who were enrolled in the cervical traction program (as part of usual care in our center), who could be followed at 3 months, and who had given their non-opposition, were included.

Patients who were under guardianship, unable to understand the protocol, diagnosed with myelopathy, cancer, arterial pathologies, fracture-dislocation or spinal infection were not included. Cervical spine x-rays are systematically performed in our center to eliminate contraindications to manual treatment.

Intervention/issue of interest (exposure)

To propose an intensive cervical traction, thirty-minute traction sessions were performed twice daily for 5 days (total of 10 sessions) by a physiotherapist. Participants were positioned in supine [13] on a flat bed. A manual traction test was performed to ensure that traction did not provoke any pain or unwanted sensations. Participants were asked to keep their gaze forwards throughout the traction to avoid muscle contraction by oculocephalogyric coupling [14]. The mechanical traction was applied at 45° from the horizontal plane formed by the bed [15] (Fig 1).

Fig 1

Cervical traction set-up.

Mechanical traction was set to 5% of the participant’s body weight on day 1 (unless not tolerated) and increased to reach 10% on the 5th day, as pain allowed, and without exceeding 12kg [14]. Within a session, the load was applied progressively over 5 minutes and pain was monitored using a VAS [16]. The target weight was then maintained for 20 minutes and then reduced gradually over the last 5 minutes. The patient then lay still for 10 minutes before getting up [14, 17]. A physiotherapist was present during the entire first session and the patients were provided with a call bell for the other sessions.

On the mornings of days 2, 3 and 4 (before the traction), the patients also underwent 15 minutes of massage. A physiotherapist performed effleurage, kneading, muscle tension release and stretching techniques as required, with the patient sitting in a massage chair [18].

Evaluation

Physiotherapists and rheumatologists who were trained in the outcomes used in the study conducted the baseline assessments on the first morning, before the traction began (D1) and on Day 5 (D5). Another pre-trained physiotherapist or a resident rehabilitation physician performed the assessments at 3 months +/- 15 days (M3).

Primary outcome

The primary outcome was the percentage of patients with a clinically important reduction in disability by M3. The Neck Disability Index combines pain intensity, personal care, lifting, reading, headaches, concentration, work, driving, sleeping and recreation [19, 20]. It has excellent reliability, internal consistency, and validity [20, 21]. It is composed of 10 questions and can be self-completed by the patient. The maximal score is 50 points, and higher scores show higher levels of disability. The minimum clinically important difference for patients with cervical radiculopathy is 7 points [19]. We therefore considered a decrease of 7 or more points in the Neck Disability Index between Day 1 (before first traction) and Mid-term (Month 3, M3)as a clinically important improvement in disability.

Secondary outcomes

Disability. Mean Neck Disability Index score was evaluated at D1, D5 and M3.

Pain. Local (cervical) and radiating (into the upper limb) pain were evaluated using a visual analogue scale (VAS) at D1, D5 and M3 [16, 22].

Central sensitization. Pain during motor imagery of flexion, rotation and lateral flexion was evaluated using a VAS [23, 24] at D1, D5 and M3.

Neuropathic pain. Evaluated using the Neuropathic Pain Diagnostic Questionnaire (DN4) at D1, D4 and M3. A score ≥4 indicates neuropathic pain [25]. The proportion of patients with neuropathic pain was compared at each time point (D1, D5 and M3).

Consumption of medication. The type and amount of medication taken for the cervical radiculopathy was recorded at each time point.

Sick leave. The number of days of sick leave since the onset of symptoms at hospitalization (D1) at M3 was reported.

Nerve recovery. Two signs of nerve recovery were evaluated at D1, D5 and M3: the deep tendon (muscle stretch) reflexes [26] and the length and mobility of various components of the nervous system (Upper Limb Nerve Tension Test 1a) [3, 27].

Monitoring of adverse events

Adverse events were monitored by a physician, a nurse and a physiotherapist. In particular we monitored pain and signs of nerve compression, hypotension when sitting up, dizziness and tinnitus, headaches, nausea, fainting, muscle damage, progression of local cervical pain to radiating pain or to loss of nerve conduction.

Ethics

The study 2017-A02004-49 began on April 9, 2018, after being granted ethical approval (Comité de Protection des Personnes Ile de France XI, approval number 18018), and was conducted in accordance with the Helsinki convention. In accordance with the legislation, oral consent was obtained status at the time of their inclusion in the study.

Statistical analysis

Sample size determination

We did not perform a sample size calculation since our aim was to conduct a pilot observational study. The number of patients was based on the predicted inclusion capacity over one year.

The percentage of patients with an improvement in disability at 3 months (decrease of at least 7 points on the Neck Disability Index between D1 and M3) was calculated.

Change in outcomes over time was evaluated using linear mixed models that took into account a random subject effect. Changes in Neck Disability Index score and pain were described by means and standard deviations at each time point. The number and proportion of patients with a positive ULNT1a was calculated at each time point. The analysis of consumption of medication, number of days of sick leave and presence of deep tendon reflexes at each time point was descriptive (numbers and percentages).

The statistical analysis was performed with “R” and the significance level was set at p≤.05.

Results

No patients refused to participate, thus thirty-six were included. Mean age was 51.1 ± 12.1 years (the distribution is illustrated in Fig 2), 20 (55.5%) were female and mean BMI was 25.4 (±3.38) kg/m²; 33.3% were unemployed or retired, 23.8% were sedentary workers, and 42.9% had jobs that involved physical work. Mean symptom onset was 22.6 ± 31.1 months before the start of treatment. All patients had cervical radiculopathy as diagnosed by the rheumatologist. Only 29 patients could be evaluated at M3: 3 were unavailable as they were undergoing surgery and 4 were lost to follow-up.

Fig 2

Frequency of patients by age.

Primary outcome: Neck Disability Index

Neck Disability Index score reduced by more than the minimum clinically important difference of 7 points in 48.3% of patients (Fig 3).

Fig 3

Proportion of patients with improvement in disability above the MCID.

Other outcomes

Disability

Neck Disability Index score decreased significantly over time (p < .001) (Table 1), from D1 to D5 (p < .001) and D1 to M3 (p < .001); no difference was found between D5 and M3 (p = .44). No difference in improvement was found according to the duration of symptoms (p>.239).

Table 1

Results and comparison of disability and pain evolution between D1, D5 and M3.

	D1	D5	M3	p (D1-D5)	p (D5-M3)	p (D1-M3)
Neck Disability Index/50; (sd))	19.1 (6.3)	14.8 (8.1)	12.1 (7.9)	< .001	p>.438	< .001
Cervical pain VAS/100; (sd)	36.7 (23.3)	15.1 (24.4)	18.7 (19.5)	< .001	p = .523	< .01
Arm pain VAS/100; (sd)	41.5 (25.0)	16.0 (17.8)	22.0 (22.7)	< .001	p = .364	< .001
Cervical flexion VAS/100; (sd)	20.0 (23.6)	12.7 (18.5)	14.8 (23.9)	= .213	= 0.475	= .915
Imagined lateral flexion VAS/100; (sd)	28.8 (23.6)	13.7 (18.1)	14.2 (21.6)	< .001	= .93	< .01
Imagined rotation VAS/100; (sd)	27.5 (23.9)	12.7 (20.1)	14.0 (22.0)	< .01	= .97	= .043

Pain

The cervical VAS score decreased significantly over time (p < .001) (Table 1), from D1 to D5 (p < .001) and D1 to M3 (p < .01); no difference was found between D5 and M3 (p = .52).

Radiating VAS score decreased significantly over time (p < .001) (Table 1), from D1 to D5 (p < .001), and D1 to M3 (p < .001); no difference was found between D5 and M3 (p = .36).

The VAS score of the imagined lateral flexion and rotation movements decreased over time (p < .01), from D1 to D5 (p < .01) (Table 1). The imagined lateral flexion VAS score also decreased from D1 to M3 (p < .001) and the imagined rotation VAS score decreased from D1 to M3 (p = .043). There was no change in VAS score for imagined flexion over time (D1-D5 (p = .22) and D1-M3 (p>.21)). For all imagined movements, there were no differences for any movement between D5-M3 (p>.91).

61.1% of patients had neuropathic pain at D1, 33.3% at D5 and 48.3% at M3 (Fig 4).

Fig 4

Proportion of patients with neuropathic pain.

Consumption of medication (Fig 5)

Use of non-steroidal anti-inflammatory drugs (NSAIDs) reduced from 22.2% at D1 to 11.4% at D5 and then 0% at M3. Use of antidepressants was 11.1 at D1, 14.3 at D5 and 10.3% at M3. Use of antiepileptics reduced from 13.9 at D1 to 14.3% at D5 and 10.3% at M3. Use of class 1 analgesics increased from 66.7 then 74.3% at D5 and then reduced to 37.9 at M3. Use of class 2 analgesics reduced from 19.4 to 17.1 then 10.3%. Use of class 3 analgesics reduced from 13.9% at D1 to 8.6% at D5 then 6.9% at M3. Use of corticosteroids reduced from 19.4 to 2.9 then 0%.

Sick leave

The average duration of sick leave was 125.0 (±331.6) days before inclusion in the protocol.

Deep tendon reflexes

Reflexes were absent in 31.7% at D1, 26.3% at D5 and 10.7% M3.

ULNT1a

The proportion of participants with a positive ULNT1a reduced from 60.6% at D1 to 36.4% at D5 (p = .066) and 36.0% at M3 (p = .11) with no difference between D5 and M3 (p = .99).

Discussion

Main findings of the present study

This prospective observational study showed a clinically important reduction in disability (> 7 points on the Neck Disability Index, [19]) in 48.3% of the patients with cervical radiculopathy 3 months after beginning an intensive cervical traction protocol. Furthermore, this improvement was not related to the duration of symptoms. Disability, local and radiating pain, central sensitization and neuropathic pain, medication consumption, and neurological status (Reflexes and ULNT1a) were all significantly improved at the end of the protocol (D5) and remained so at the 3-month follow up. Although this study was un-controlled, we believe that in view 1) of the chronicity of the symptoms (mean duration 20.4 months, SD = 31.2), and 2) the short duration of the protocol (effects found after only 5 days), these results can be attributed to the effects of the traction protocol.

The primary outcome of the present study (proportion of patients with a change in Neck Disability Index greater than the minimum clinically important difference) could not be directly compared with other studies since they did not use this outcome. The secondary disability outcome (change in Neck Disability Index at 3 months) is relatively common in the literature, however comparison with similar studies [12, 28–31] was limited by the use of different methods: the Neck Disability Index can be rated out of 50 or 100 ([29], please note that Table 2 shows all results converted to a scale out of 50 points), however the authors did not always specify their choice (based on the values reported, we made the assumption that [30] used a scale out of 100 points), and one study used a VAS to evaluate disability [29]. Four of the 5 studies shown in Table 2 used the Neck Disability Index at mid-term and thus we were able to compare our results with these. Three of these studies (Moustafa et al., Fritz et al. and Young et al.) found reductions in disability of a similar order to the present study (around 7 points) at mid-term. Importantly, the improvement in disability was greater than that which would be expected for the normal course of the disease [6], suggesting it was indeed due to the treatment.

Table 2

Comparison of effects of traction in the literature.

	Disability			Cervical pain			Arm pain			Pain (no distinction between arm and cervical)
	baseline	T1	T2	baseline	T1	T2	baseline	T1	T2	baseline	T1	T2
Jellad et al. (2009)	48,1 (VAS)	23,2 (VAS)	No Data	58,3 (VAS)	33,3 (VAS)	No Data	66 (VAS)	31,9 (VAS)	No Data	No Data	No Data	No Data
B group
Moustafa et Diab (2014)	18,8 (NDI)	13,5 (NDI)	17,3 (NDI)	6,5 NPRS	4,6 NPRS	6,30 NPRS	6,1 NPRS	4,2 NPRS	5,8 NPRS	No Data	No Data	No Data
A group
Fritz et al. (2014)	15,4 (NDI)	4,8 (NDI)	8,7 (NDI)	3,9 NPRS	1,00 NPRS	1,1 NPRS	4,3 NPRS	1,4 NPRS	0,9 NPRS	No Data	No Data	No Data
Mech tract group
Aydin et Yazicioglu (2012)	No Data	No Data	No Data	No Data	No Data	No Data	No Data	No Data	No Data	69,2 (VAS)	24,6 (VAS)	No Data
Traction group
Young et al. (2009)	19,8 (NDI)	14 (NDI)	11,1 (NDI)	No Data	No Data	No Data	No Data	No Data	No Data	6,3 NPRS	4,20 NPRS	3,4 NPRS
MTEXTraction Group
Afzal et Al. (2019)	22,4 (NDI)	10,6 (NDI)	No Data	No Data	No Data	No Data	No Data	No Data	No Data	7,5 NPRS	3,08 NPRS	No Data
Traction group
Results for patients	19,1 (NDI)	14,8 (NDI)	12,1 (NDI)	36,7 (VAS)	15,1 (VAS)	18,7 (VAS)	41,5 (VAS)	16,0 (VAS)	22,0 (VAS)	No Data	No Data	No Data

T1 = just at the end of the protocol. T2 = mid-term evaluation; VAS: Visual Analogue Scale; NPRS: Numeric Pain Rate Scale; NDI: Neck Disability Index, The NDI has been scaled to 50 to allow comparison.

The reductions in cervical and radiating arm pain were also above the minimum clinically important differences for these variables: 8.1/100 for cervical pain and 10.4/100 for radiating arm pain [32]. The baseline level of pain was lower in our study compared with the studies shown in Table 2. This is likely due to differences in care provided in different countries. Furthermore, comparison is hindered by different methods of pain measurement: some used the Numeric Pain Rating Scale (NPRS) [12, 28, 30, 31] and not all distinguished cervical and radiating pain [12, 31, 33]. Among the studies that used a VAS to measure pain, the reduction varied from 25 to 45 points. In the present study the reduction was around 20 points. This can be considered similar in view of the fact the baseline levels were lower, thus there was less potential for reduction.

The evaluation of the effect of traction on central sensitization was novel in this study. It has previously been shown that in the case of chronic pain, the flow and integration of neural activity within the pain matrix [34, 35] is altered [24]. These changes can be indirectly evaluated by assessing pain produced during motor imagery [24], which is normally painless. The baseline measures of pain during cervical flexion, extension and rotation demonstrated the presence of central sensitization in the patients included, likely due to their long history of symptoms [24]. This pain reduced by approximately 50% following the traction and, importantly, the reduction was maintained 3 months later. The positive evolution of pain during imaginary movement, despite the long duration of the symptoms, may indicate that central remodeling occurred [24]. This fact is important because patients with central sensitization seems to have more severe pain, poorer general health-related quality of life, and greater levels of pain-related disability, depression, and anxiety [36]. There is some evidence that low-back pain treatment reverses abnormal brain function [37, 38] but, to our knowledge, this is the first time that this reversal has been demonstrated following traction for cervical radiculopathy.

To our knowledge, this is the only study to have evaluated the effect of cervical traction on neuropathic pain in the case of cervical radiculopathy. The percentage of patients with a score above 4 points on the DN4 reduced from 61.1% to 48.3% at M3, indicating that 8 patients no longer had neuropathic pain [25, 39]. This is very interesting because neuropathic pain is highly challenging to treat. Most currently available treatments are only moderately effective and have side effects that limit their use (e.g. medications) [40]. The results of the present study demonstrate that, in some patients, neuropathic pain may be reduced by an intense, short and specific protocol.

Few studies have evaluated drug consumption as a treatment outcome for cervical radiculopathy [3]. However, this parameter is important for two reasons. Firstly, an increase in drug intake could favorably influence the primary outcome (and vice versa). Secondly, a reduction in drug consumption is an important indicator of treatment success, as well as being important for the patients’ overall health. Furthermore, by M3, none of the patients were taking NSAIDs or corticosteroids. The use of level 2 and 3 analgesics, as well as anti-epileptic drugs to reduce neuropathic pain, was also decreased at D5 and M3. Only the prescription of antidepressants did not change. This was not unexpected since all patients had chronic pain, however it is unlikely to have affected the improvement in disability and pain.

We evaluated variables relating to nerve recovery because of the specific decompression effect of cervical traction on nerve tissue [3, 11]. The ULNT1a evaluates the nerve’s ability to slide and elongate [41] and thus provides information regarding the biomechanics of the peripheral nerve tissue [41]. Reflexes, on the other hand, provide an indication of nerve conduction [42] which appeared to increase slightly by the end of the traction protocol and more substantially by M3. However, there was only a trend towards an improvement in the biomechanics of the nerve. The traction thus appeared to have a greater effect on nerve conduction through decompression than on any inflammation present in the nerve, as has previously been reported for other manual therapy techniques [43].

Implications and explanation of findings

The improvement in all the clinical variables (Neck Disability Index, intensity and type of pain, drug consumption, as well as ULNT1a and deep tendon reflexes) following the traction protocol is positive. In their review, Romeo et al. (2018) suggested that a higher number of traction sessions led to a greater improvement in outcomes. Our protocol involved a number of sessions (10 sessions) that was comparable with studies in the literature (7–15 sessions), however we provided these sessions over a shorter time-frame (5 days). This more intensive protocol has several advantages. Firstly, the recovery time may have been accelerated (5 days). This may reduce the duration of sick leave which would in turn reduce the costs associated with cervical radiculopathy.

Study limitations

The main limitation of this work was the number of participants lost to follow-up, however this is quite typical in this population [28] (Table 3). It is due to the fact some patients had returned to work and did not attend their final consultation, while conservative treatment had failed for several others and surgery was planned before the end of the follow-up.

Future directions

Randomized, controlled trials comparing traction with sham traction are now required to fully determine the effectiveness of cervical traction on cervical radiculopathy. The optimal traction modalities, such as pull angle and weight, also need to be determined.

Conclusion

Disability reduced by more than the minimum clinically important difference in almost half the participants following the intensive traction protocol. In addition, cervical and radiating arm pain, pain with imagined movements and neuropathic pain also improved. Furthermore, all the secondary outcomes also improved. These results are encouraging and suggest that this complex condition can be treated with relatively simple methods.

4 May 2021

PONE-D-21-09986

Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: an exploratory, prospective, observational pilot study

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Roulleau T and colleagues here present the results of their study named “Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: an exploratory, prospective, observational pilot study”. In this work the authors conducted an observational study of 36 patients referred by their general practitioner for symptoms suggestive of cervical radiculopathy, submitting them to a specific cervical traction protocol, analyzing post-protocol symptoms and signs also through the help of Neck Disability Index. They found that disability was significantly reduced in almost half of the participants, suggesting such protocol as an alternative to longer traction protocols, at the comparison of whom the present protocol appeared similar in terms of efficacy.

Although the work is sufficiently well written and clear from a stylistic point of view, I honestly feel it suffers from heavy scientific rigor issues that definitely affect its potential scientific interest.

I list here my major concerns:

- Introduction section is really too long, please re-write it in a more summarized manner;

- Introduction section, lines 63-66 definitely need references, if available. Moreover, the entire paragraph should be re-written specifying for which pathologies such considerations are referred. Are the authors speaking about cervical radiculopathy due to disk herniation or stenosis or tumors etc.? Anyway, I would be very interested in reading some reference that states that intervention is not indicated for cervical radiculopathy in cervical disk herniations with pain resistant to medications.

- Material and methods. Was cervical radiculopathy diagnosed just with clinical examination, without performing MR or CT imaging to patients? No specific radiological control before submitting them to cervical traction? Really? It appears, at least, risky.

- No neurosurgeons nor ortophaedic surgeons appeared to be involved in the study. Hence, how can patients be informed about their condition and supposed diagnosis? From the reading of this work it seems that, simply, patients with cervical radiculopathy that come to your clinic are directly submitted to cervical traction, without any diagnosis nor alternative treatment proposal; If it’s not, re-write the section entirely, please;

- English written language may beneficiate from a mother-tongue speaker review.

Reviewer #2: To Whom It May Concern,

This is an exceptional paper. However, there are a few data points that would add to the paper. Those points are a graphic (histogram) representation of the age breakdown in intervals. We know that older patients are more prone to degenerative spondylosis however, it would be helpful to know where the majority of the study population resides in age distribution. Also, in the methods section I could not discern the exact method used to apply traction. For example, did you all use Gardner Wells Tongs or strap system? Otherwise, well written paper.

Reviewer #3: First, I would like to express sincere gratitude to get an opportunity to review the manuscript. The endeavor of the authors is appreciated. The authors have studied effect of intensive cervical traction with respect to mid-term disability and pain in patients with cervical radiculopathy. However, there is some scope for its improvement.

Specific comments:

1. There are some contradictory statements in the paper. For example, as per methods section 36 patients were enrolled in the study whereas as per results section of main text 42 patients were enrolled. Kindly explain.

2. The study design is not clear. Was there any control arm? The conclusion states there was some comparison done. The details of study design need to be well described.

3. Kindly define mid-term effect and intensive cervical traction.

4. It would be better if study design were clearly mentioned in title, abstract and main text.

5. Methods sections is supposed to be core of any study. Here, methods section contains inadequate information. For example, following components for methods section need to be well described.

i. Details of Study design

ii. Setting

iii. Sampling technique

iv. Participant

v. Primary and secondary outcome variables with working definition

vi. Intervention/issue of interest (exposure)

vii. Comparison (if done)

viii. Ethics and end point

ix. Statistical analysis

6. Kindly re-frame the references as per the guidelines to authors in the home page of journal. Further, most of the studies included in the reference section seem to be the studies published more than 10 years back. If possible, please add recent studies.

7. The tables need to be re-organized. For example, table 2 appears first. Further, kindly provide study size in captions. It would be better to frame all the tables in homogenous format.

Section wise comments

1. Abstract contains inadequate information.

a. Mention the design of the study clearly.

b. Methods section is not well described.

c. Kindly start results section with baseline information of participants.

2. The introduction is lengthy. Please DELETE INFORMATION UNRELATED TO OBJECTIVE so that the section is short and sweet. Kindly shorten this section and delete unrelated information. Kindly focus on three elements of introduction

a. What is known about the topic? (Background)

b. What is not known? (The research problem)

c. Why the study was done? (Justification)

3. Methods section determines the results. Kindly follow the checklist. Further, kindly focus on three basic elements of methods section.

a. How the study was designed?

b. How the study was carried out?

c. How the data were analyzed?

4. The discussion section needs to be described scientifically. Kindly frame it along the following lines:

a. Main findings of the present study

b. Comparison with other studies

c. Implication and explanation of findings

d. Strengths and limitations

e. Conclusion, recommendation and future directions

5. Conclusion needs to provide answers for each objective clearly in a sentence or two.

Reviewer #4: Journal of PLOS ONE

27 April 2021

Manuscript No: PONE-D-21-09986_reviewer

“Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: an exploratory, prospective, observational pilot study”

Dear editorial Teams

In my opinion the manuscript has well written. However, I have several suggestions that I think would improve the manuscript:

a) The Introduction and the Discussion sections are long and redundant.

b) Additional descriptions as NDI (line 155- 162) should be summarized, and ets.

c) Researchers stated that “ forty-two patients were included” and “Only 29 patients could be evaluated at M3: 3 were unavailable as they were undergoing surgery and 4 were lost to follow-up” 42= 29+ 3+ 4+ X? please explain the other 6 patients.

d) Please, explain the type of traction used.

Parisa Azimi, MD,

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

Reviewer #3: Yes: Dr. Satish Prasad Barnawal

Reviewer #4: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

10 Jun 2021

We would like to thank the editor and reviewers for taking the time to evaluate our work. We hope that the changes made will meet their expectations.

Reviewer #1:

Roulleau T and colleagues here present the results of their study named “Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: an exploratory, prospective, observational pilot study”. In this work the authors conducted an observational study of 36 patients referred by their general practitioner for symptoms suggestive of cervical radiculopathy, submitting them to a specific cervical traction protocol, analyzing post-protocol symptoms and signs also through the help of Neck Disability Index. They found that disability was significantly reduced in almost half of the participants, suggesting such protocol as an alternative to longer traction protocols, at the comparison of whom the present protocol appeared similar in terms of efficacy.

Although the work is sufficiently well written and clear from a stylistic point of view, I honestly feel it suffers from heavy scientific rigor issues that definitely affect its potential scientific interest.

I list here my major concerns:

- Introduction section is really too long, please re-write it in a more summarized manner;

We thank reviewer 1 for this suggestion and have modified as suggested

- Introduction section, lines 63-66 definitely need references, if available. Moreover, the entire paragraph should be re-written specifying for which pathologies such considerations are referred. Are the authors speaking about cervical radiculopathy due to disk herniation or stenosis or tumors etc.? Anyway, I would be very interested in reading some reference that states that intervention is not indicated for cervical radiculopathy in cervical disk herniations with pain resistant to medications.

We have added reference "9" and we have also added "or myelopathy" line 59. Nikolaidis et al (2010) which was quoted after in the paragraph and thank reviewer 1 for this clarification request. Nikolaidis et al (2010) explain a “low quality evidence that surgery may provide pain relief faster than physiotherapy or hard collar immobilization in patients with cervical radiculopathy; but there is little or no difference in the long-term”. We confirm that we do not mention any lack of interest in surgery for patients with cervical radiculopathy in cervical disk herniations with pain resistant to medications. We thank reviewer 1 for his clarification.

- Material and methods. Was cervical radiculopathy diagnosed just with clinical examination, without performing MR or CT imaging to patients? No specific radiological control before submitting them to cervical traction? Really? It appears, at least, risky.

We thank reviewer 1 for this comment. Patients were diagnosed according to one of the proposals of Romeo et al (2018). In their meta-analysis, they select studies where patients meet these criteria: 1) diagnosis based on magnetic resonance imaging, electromyography, or nerve conduction velocity testing, 2) positive results on at least 3 out of 4 tests, according to clinical prediction rules,21 or 3) symptoms associated with CR, such as pain radiating to the arm, with or without motor or sensitive dysfunction. We have used criteria 3) in this study. To confirm absence of risk, like explain line 159, we performed systematically a cervical spine x-rays

- No neurosurgeons nor ortophaedic surgeons appeared to be involved in the study. Hence, how can patients be informed about their condition and supposed diagnosis? From the reading of this work it seems that, simply, patients with cervical radiculopathy that come to your clinic are directly submitted to cervical traction, without any diagnosis nor alternative treatment proposal; If it’s not, re-write the section entirely, please;

Indeed, we understand the issue. In our health care system, the intervention of neurosurgeons is second line. Diagnostic confirmation is provided by rheumatologists and cervical traction is often performed in rheumatology or physical medicine rehabilitation departments.

- English written language may beneficiate from a mother-tongue speaker review.

We are surprised by this remark. The document has been proofread by Johanna Robertson PT PhD, professional medical and science translator and native British speaker, as evidenced by the attached document. We have written an acknowledgement to this effect (line 437). A new proofreading was done in order to improve manuscript as requested.

Reviewer #2:

To Whom It May Concern,

This is an exceptional paper. However, there are a few data points that would add to the paper. Those points are a graphic (histogram) representation of the age breakdown in intervals. We know that older patients are more prone to degenerative spondylosis however, it would be helpful to know where the majority of the study population resides in age distribution. Also, in the methods section I could not discern the exact method used to apply traction. For example, did you all use Gardner Wells Tongs or strap system? Otherwise, well written paper.

We thank reviewer 2 for his compliments and suggestions for improvement.

We have added a graphical table in order to have a better representation of the age of the patients.

We have also added a picture (fig 1) of the device in Methods section to explain the proposed tractions.

Reviewer #3:

First, I would like to express sincere gratitude to get an opportunity to review the manuscript. The endeavor of the authors is appreciated. The authors have studied effect of intensive cervical traction with respect to mid-term disability and pain in patients with cervical radiculopathy. However, there is some scope for its improvement.

Specific comments:

1. There are some contradictory statements in the paper. For example, as per methods section 36 patients were enrolled in the study whereas as per results section of main text 42 patients were enrolled. Kindly explain.

We thank reviewer 3 for this comment. This is an error on our part, there are 36 patients included in this work. We have made the correction on line 26 and line 250 and please apologize to the reviewers for this error.

2. The study design is not clear. Was there any control arm? The conclusion states there was some comparison done. The details of study design need to be well described.

We thank reviewer 3 for this question. There is no control arm. The study is observational, as explained in the title and method. We have added the sentence "All patients received the same treatment" to line 136.

3. Kindly define mid-term effect and intensive cervical traction.

To explicit “mid-term”, we have changed the phrase "at three month" to "at mid-term" line 31. We have also made this clarification on line 197.

To explicit an intensive cervical traction, we added : "To propose an intensive cervical traction protocol" just before sentence "thirty-minute traction sessions were performed twice daily for 5 days (total of 10 sessions) by a physiotherapist" ligne 162. We thank Reviewer 3 for requesting these clarifications.

4. It would be better if study design were clearly mentioned in title, abstract and main text.

We thank reviewer 2 for this remark. Nevertheless, we have mentioned in the title, abstract and main text the "observational" character of our work. We hesitated with the term "cohort study" which seemed less appropriate for a number of subjects below several hundred.

5. Methods sections is supposed to be core of any study. Here, methods section contains inadequate information. For example, following components for methods section need to be well described.

i. Details of Study design

ii. Setting

iii. Sampling technique

iv. Participant

v. Primary and secondary outcome variables with working definition

vi. Intervention/issue of interest (exposure)

vii. Comparison (if done)

viii. Ethics and end point

ix. Statistical analysis

We thank reviewer 2 for this remark. A formatting error has been corrected to clarify this point. We have taken up several missing headings suggested by Reviewer 3 in order to clarify this legitimate request. In particular, we have added "Details of Study design" line 133, "Intervention/issue of interest (exposure)" line 161, and we have moved the paragraph on ethical approaches to conducting this research to line 226 "Ethics".

6. Kindly re-frame the references as per the guidelines to authors in the home page of journal. Further, most of the studies included in the reference section seem to be the studies published more than 10 years back. If possible, please add recent studies.

We thank proofreader 3 for these remarks. We have changed the bibliography from the "vancouver" style to the "plos one" style available in Zotero followed by a manual check. We understand the remark about studies that may be more than ten years old. Indeed, it is interesting to note how few recent studies on this subject we could find, which motivated our interest.

7. The tables need to be re-organized. For example, table 2 appears first. Further, kindly provide study size in captions. It would be better to frame all the tables in homogenous format.

Table 1 is quoted in the introduction. It therefore seems appropriate to leave it as "Table 1". Nevertheless, we agree with reviewer 3. We have rearranged and modified the tables to make them consistent.

Section wise comments

1. Abstract contains inadequate information.

a. Mention the design of the study clearly.

b. Methods section is not well described.

We have added the sentence " All patients underwent the same treatment " to clarify the abstract line 13.

c. Kindly start results section with baseline information of participants.

We have made this change and thank you for it.

2. The introduction is lengthy. Please DELETE INFORMATION UNRELATED TO OBJECTIVE so that the section is short and sweet. Kindly shorten this section and delete unrelated information. Kindly focus on three elements of introduction

a. What is known about the topic? (Background)

b. What is not known? (The research problem)

c. Why the study was done? (Justification)

The introduction has been revised to meet the expectations of reviewers 3 and 4. We thank them for their advice.

3. Methods section determines the results. Kindly follow the checklist. Further, kindly focus on three basic elements of methods section.

a. How the study was designed?

b. How the study was carried out?

c. How the data were analyzed?

We hope that the new layout and additions will meet the reviewer's expectations3

4. The discussion section needs to be described scientifically. Kindly frame it along the following lines:

a. Main findings of the present study

b. Comparison with other studies

c. Implication and explanation of findings

d. Strengths and limitations

e. Conclusion, recommendation and future directions

We thank reviewer 3 for this feedback. We have added the suggested headings and redesigned this section to make it easier for practitioners to read.

5. Conclusion needs to provide answers for each objective clearly in a sentence or two.

We thank reviewer 3 for this suggestion and have added " In addition, cervical and radiating arm pain, pain with imagined movements and neuropathic pain also improved " line 429.

Reviewer #4:

Journal of PLOS ONE

27 April 2021

Manuscript No: PONE-D-21-09986_reviewer

“Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: an exploratory, prospective, observational pilot study”

Dear editorial Teams

In my opinion the manuscript has well written. However, I have several suggestions that I think would improve the manuscript:

a) The Introduction and the Discussion sections are long and redundant.

We have taken this comment into account and thank reviewer 4. We have amended the text accordingly for the introduction. We have redesigned the discussion to make it slightly shorter, but also more reader friendly.

b) Additional descriptions as NDI (line 155- 162) should be summarized, and ets.

We thank Reviewer 3 for this remark. We have taken his advice and deleted several parts in the outcomes description that were not essential to the understanding of the study.

c) Researchers stated that “ forty-two patients were included” and “Only 29 patients could be evaluated at M3: 3 were unavailable as they were undergoing surgery and 4 were lost to follow-up” 42= 29+ 3+ 4+ X? please explain the other 6 patients.

We thank reviewer 4 for this remark which is in line with that of reviewer 3. This is an error on our part, there are 36 patients included in this work. We have made the correction on line 35 and 250. We apologize for this error..

d) Please, explain the type of traction used.

We thank reviewer 4 for this comment which is in line with reviewer 2. We have added a picture (fig1 ) to be more explicit about the type of traction.

We sincerely thank the reviewers for their time in reviewing our work. We feel that this feedback has been productive and has helped to improve the communication proposal for our work. We hope we have met their expectations.

For the authors,

Dr Thomas Rulleau PT PhD

22 Jul 2021

PONE-D-21-09986R1

Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: an exploratory, prospective, observational pilot study

PLOS ONE

Dear Dr. Rulleau,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

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Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #3: (No Response)

Reviewer #4: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

Reviewer #3: Partly

Reviewer #4: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: (No Response)

Reviewer #3: The paper is in better shape. Congratulations to the authors for such a nice work. Yet, some modifications need to be made before publication. Kindly refer to the following aspects.

1. Conclusion needs to provide answers for each objective clearly in a sentence or two.

a. Here the conclusion does not support the findings of the paper.

b. As the study was not comparative study, such statements need to be removed.

c. The conclusion should only contain information pertaining to findings of the current paper (not other studies).

2. Abstract contains inadequate information.

a. Mention the design of the study clearly.

b. Methods section is not well described.

3. Please DELETE INFORMATION UNRELATED TO OBJECTIVE so that the section is short and sweet. Kindly shorten this section and delete unrelated information. Kindly focus on three elements of introduction

a. What is known about the topic? (Background)

b. What is not known? (The research problem)

c. Why the study was done? (Justification)

4. There are too many strikethrough marks. Kindly delete the text completely which has been asked to delete. At the same time, please highlight the changes that have been made.

5. It would be better to shorten the paper. It seems there is too much of information.

6. Kindly mention tables and figures in line with recommendations of journal. For example, table is not required in introduction.

Reviewer #4: Thank you for your efforts. All comments have been addressed. In this study the effect of cervical traction on neuropathic pain in the case of cervical radiculopathy was assessed.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No

Reviewer #3: Yes: Dr. Satish Prasad Barnawal

Reviewer #4: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

26 Jul 2021

We thank the reviewers for their positive comments on our work. We hope that this version will fully satisfy them.

Reviewer #2: All comments have been addressed

Reviewer #3: (No Response)

Reviewer #4: All comments have been addressed

We thank the reviewers 2 for their validation of our comments and our new version

Reviewer #2: (No Response)

We thank the reviewer 2 for his validation of this new version

Reviewer #3: The paper is in better shape. Congratulations to the authors for such a nice work. Yet, some modifications need to be made before publication. Kindly refer to the following aspects.

we thank reviewer 3 for this compliment

1. Conclusion needs to provide answers for each objective clearly in a sentence or two.

a. Here the conclusion does not support the findings of the paper.

b. As the study was not comparative study, such statements need to be removed.

c. The conclusion should only contain information pertaining to findings of the current paper (not other studies).

We thank reviewer 3 for these remarks. We have modified the document according to this advice. We have removed the reference to the comparison of other studies line 362-364.

2. Abstract contains inadequate information.

a. Mention the design of the study clearly.

b. Methods section is not well described.

We thank reviewer 3 for this analysis. We have added the words "prospective and open" just before “observational study” line 26. To improve clarity, we have also modified the following paragraph by adding the main objective of the study. Finally, we have rewritten the following sentence to make it clearer (line 29-32).

3. Please DELETE INFORMATION UNRELATED TO OBJECTIVE so that the section is short and sweet. Kindly shorten this section and delete unrelated information. Kindly focus on three elements of introduction

a. What is known about the topic? (Background)

b. What is not known? (The research problem)

c. Why the study was done? (Justification)

We understand this remark less. The text has been deeply reworked during our last submission in order to answer this request. It is, in fact, extremely short by keeping only the essential useful to physicians and physiotherapists involved in these tractions. We understand that other expert actors may want an even shorter text, but it seems useful to us here to keep the remaining elements to contextualize.

4. There are too many strikethrough marks. Kindly delete the text completely which has been asked to delete. At the same time, please highlight the changes that have been made.

We sent two versions, as requested by the publisher, one with the marks, the other without, to clarify the reviewers' re-reading of the changes. We have, of course, respected this request at every stage.

5. It would be better to shorten the paper. It seems there is too much of information.

We thank reviewer 3 for this comment. We have streamlined our text to meet this request.

6. Kindly mention tables and figures in line with recommendations of journal. For example, table is not required in introduction.

We understand the comment of reviewer 3. We had quoted the table in the introduction. In accordance with the recommendations to the authors, we have therefore illustrated with the table. We have made the modification requested by reviewer 3 and the table now appears in the discussion when it is quoted a second time in the text.

Reviewer #4: Thank you for your efforts. All comments have been addressed. In this study the effect of cervical traction on neuropathic pain in the case of cervical radiculopathy was assessed.

We thank the reviewer 4 for this compliment and validation of this new version

Submitted filename: response to reviewers 20210726.docx

Click here for additional data file.

28 Jul 2021

Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: an exploratory, prospective, observational pilot study

PONE-D-21-09986R2

Dear Dr. Rulleau,

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PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

30 Jul 2021

PONE-D-21-09986R2

Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: an exploratory, prospective, observational pilot study

Dear Dr. Rulleau:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

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on behalf of

Dr. Panagiotis Kerezoudis

Academic Editor

PLOS ONE