Diaphragmatic plication offers functional improvement in dyspnoea and better pulmonary function with low morbidity

Abstract

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was as follows: In adults with unilateral diaphragmatic paralysis, does diaphragmatic plication offer functional improvement in dyspnoea, better pulmonary function tests (PFTs) and return to activity? A total of 126 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The authors, date and country of publication, patient group studied, surgical approach, study type, relevant outcomes and results of these articles are tabulated. Those articles reporting improvement in PFTs following plication, documented this benefit in the following parameters: mean forced vital capacity (range 17–40%), forced expiratory volume at 1 sec (range 21–27%), functional residual capacity (range 20–21%) and total lung capacity (range 16–19%). The percentage of postoperative improvement in shortness of breath as measured by a dyspnoea score was reported to be between 90 and 96% in the thoracotomy group and 100% in the Video Assisted Thoracoscopic Surgery (VATS) group, the dyspnoea score that was used in all the studies was a visual analogue scale between 0 and 10 where 0 is no dyspnoea and 10 is the worst dyspnoea a patient can have. One of the studies reported postoperative normalization in ventilation perfusion scan (VQ) scan parameters when compared with the preoperative mismatch. Complication rate was similar between the two groups, while the mortality rate was 4% in the thoracotomy group and 0% in the VATS group. The total number of patients included in all the studies combined was 161. All reports included in this review are observational studies (one cohort study and the remainder being case series); therefore, the risk of selection, information and publication biases are high and conclusions should be implemented with caution. We conclude that diaphragmatic plication can improve the functional status, shortness of breath and PFTs of patients with unilateral diaphragm paralysis. Patients undergoing a VATS approach appear to have more advantages in objective and subjective measures (including PFTs, dyspnoea score, length of hospital stay and postoperative complications). Further research with high-quality study designs is advised, focussing mainly on the long-term benefits and assessment of health-related quality of life.

INTRODUCTION

A best evidence topic was constructed according to a structured protocol. This protocol is fully described in the ICVTS [1].

CLINICAL SCENARIO

A 51-year old man is referred to you in the thoracic surgery clinic with dyspnoea. His family physician has completed all the appropriate investigations, which showed a paralyzed right hemi-diaphragm but no obvious underlying cause. After explaining the operation, he asks to what extent he might expect an improvement in his breathing, function and return to normal physical activity and if there were any possible complications.

THREE-PART QUESTION

In [adults with unilateral diaphragmatic paralysis] does [diaphragmatic plication] compared with [conservative treatment] result in [better improvement in dyspnoea, pulmonary function tests (PFTs) and return to physical activity?]

SEARCH STRATEGY

We searched OVID SP 1970-January 2012 for both EMBASE and MEDLINE databases.

The following search strategy was used for EMBASE (exp Thoracotomy/OR exp Thoracoscopy/OR exp video-assisted thoracoscopic surgery/OR thoracotom$.mp OR thoracoscop$.mp OR pleuroscop$.mp OR Thoracic Surgery.mp) AND (Diaphragm paralysis.mp OR ((respirat$.mp or diaphragm$.mp) adj3 (paralys$.mp or eventration,mp or palsy,mp)))

The following search strategy was used for the MEDLINE (exp Thoracotomy/OR thoracoscopy/OR thoracic surgery, video-assisted/ OR thoracotomy$.mp OR thoracoscop$.mp OR pleuroscop$.mp OR thoracic surger$.mp.) AND (Respiratory Paralysis/OR ((respirat$.mp OR diaphragm$.mp) adj3 (paralys$.mp OR eventration.mp OR palsy.mp))

SEARCH OUTCOME

A total of 126 articles were identified including hand search of which 13 articles were deemed relevant. These articles are listed in Table 1.

Table 1:

Summary of best evidence topics

Author, date, country (level of evidence)	Patient group	Outcome	Key results	Comments
Sung et al., 1970–91, Chin Med J, China [9] Case series (level 4)	7 patients underwent thoracotomy, mean age of 44 years (range: 32–65). No symptoms in 2 patients. The other 5 patients had symptoms for a minimum of 1 year	PFTs Symptomatic improvement	Clinical improvement in symptoms in all except 1 patient (transient improvement) PFTs minimal improvement (done in 2 patients only)	Follow-up of 3 months to 12 years (mean 65 months)
Wright et al., 1979–84, J Thorac Cardiovasc Surg, UK [10] Case series (level 4)	7 patients underwent thoracotomy, mean age of 53 years (range: 37–67). Duration of symptoms was 4 months to 4 years (mean 1.8 year)	PFTs Dyspnoea score	Improvement in PFTs and dyspnoea score. LOS is 12 days (10–15). No complications	Follow-up of 4–58 months
Graham et al., 1979–89, Ann Thorac Surg, UK [11] Case series (level 4)	17 underwent thoracotomy, mean age is 53.7 ± 13.8, diagnosis of 4 months to 4 years (mean 1.8 years)	PFTs Dyspnoea score	Improvement in PFTs and dyspnoea score	Follow-up of 5 years
Higgs et al., 1983–90, Eur J Cardiothorac Surg, UK [8] Case series (level 4)	19 (only 15 participated in the f/u) underwent thoracotomy, mean age of 55 years (range: 34–73), mean duration of symptoms is 24 months (range: 3–60), mean duration of follow-up is 10 years (range: 7–14)	PFTs Dyspnoea score	Improvement in PFTs, Dyspnoea scores improved in 12/15. 93% reported satisfaction with surgery	Follow-up of 7–14 years (mean 10 years)
Calvinho et al., 1988–2007, Eur J Cardiothorac Surg, Portugal [12] Case series (level 4)	20 underwent thoracotomy; mean age is 56 ± 15.6, diagnosis of more than 1 year	PFTs Dyspnoea score	Improvement in PFTs and dyspnoea score. Chronic pain in 2 patients	Follow-up for 4–206 months (mean 59.6 months)
Mouroux et al., 1992–2003, Ann Thorac Surg, France [7] Case series (level 4)	12 patients underwent VATS, mean age of 57.7 ± 14.8 years, all the patients had symptoms (mainly dyspnoea) for unknown period of time	PFTs	Improvement in PFTs and function in all patients. Pneumonia in 1 patient	Follow-up of 4 months to 4 years (mean of 64.4 months)
Lai et al., 1996–98, Ann Thorac Surg, Australia [13] Case series (level 4)	5 patients underwent mini-thoracotomy, no patients’ characteristics other than being adults.	Symptomatic improvement	Symptoms improvement. Minimal morbidity (not specified). LOS 4 days	Follow-up period not mentioned
Versteegh et al., 1996–2006, Eur J Cardiothorac Surg, Netherlands [14] Case series (level 4)	17 patients underwent thoracotomy (some are bilateral), mean age of 62 years (range: 37–89), minimal duration of symptoms is 1 year	PFTs Dyspnoea core	Improvement in PFTs and dyspnoea score. Three reported deaths (myocardial infarction, respiratory failure and thromboembolism)	Follow-up of 1.2–8.7 years (mean of 4.9 years)
Knight et al., 1997–98, Ann Thorac Cardiovasc Surg, Australia [6] Case series (level 4)	3 patients underwent VATS; mean age is 60.3 years (range: 55–69). The 3 patients had marked dyspnoea on exertion for an unspecified period of time	PFTs VQ scan Symptomatic improvement	improvement in PFTs, symptoms and VQ scan parameters	Minimal follow, up for 2 years.
Freeman et al., 2001–05, Ann Thorac Surg, USA [4] Cohort study (level 2b)	22 patients underwent VATS and 3 patients underwent thoracotomy, mean age is 49 years, duration of symptoms was at least 6 months. 7 patients had no surgical intervention, mean age is 53 years; decision for not having surgery was made by the patients for different reasons	PFTs	Improvement in PFTs in the surgical group. LOS was 1.7 day less in the VATS group One wound infection in the VATS group and one DVT in the thoracotomy group Recurrent hospitalization and loss of job in the non-surgical group	Follow-up is 6 months after surgery
Freeman et al., 2001–07, Ann Thorac Surg, USA [5] Case series (level 4)	30 patients underwent VATS and 11 underwent thoracotomy, mean age is 57 ± 20 years, minimal duration of symptoms is 6 months to be offered surgery	PFTs Dyspnoea score Functional status	Improvement in PFTs in all patients 90% (37/41) reported improvement in dyspnoea score and functional status (contains patients reported from previous study [4])	Follow-up of 49–80 months (mean of 57 months)
Celik et al., 2003–06, J Thorac Cardiovasc Surg, Turkey [15] Case series (level 4)	13 patients underwent thoracotomy, mean age of 60 years (range: 36–66), mean duration of symptoms was 33 months (range: 22–60 months)	PFTs Dyspnoea score	Improvement in PFTs and dyspnoea score in all except 1 patient died in the postoperative period from sepsis	Follow-up of 4 to 7 years (mean 5.4 years)
Kim et al., 2005–06, Interact CardioVasc Thorac Surg J, Republic of Korea [16] Case series (level 4)	4 patients underwent VATS, mean age of 49.5 ± 10.2 years, all the patients had symptoms (mainly dyspnoea) for unreported period of time	Symptomatic improvement	Improvement in symptoms at 6 months in all patients	Follow-up of 9–22 months (mean of 17.3 months)

VATS: video assisted thoracoscopic surgery; VQ: ventilation perfusion scan; DVT: deep vein thrombosis; LOS: length of hospital stay.

COMMENTS

Dyspnoea on exertion and orthopnea are the most common symptoms in patients with diaphragmatic eventration [2]. During inspiration, the normal caudal movement of the diaphragm is impaired, causing decreased volumes resulting in dyspnoea. The affected diaphragm might have minimal movement, no movement or paradoxical movement. [2] It has been shown that, in patients with unilateral diaphragmatic paralysis, there is a significant decrease in the tidal volume, trans-diaphragmatic pressure, the ratio of gastric to oesophageal pressure and dynamic lung compliance, this is associated with an increase in oesophageal pressure and the work of breathing per litre of ventilation [3]. In subjects undergoing repair of unilateral diaphragmatic paralysis, these parameters demonstrate marked improvement [3].

This review focuses on the improvement in PFTs, shortness of breath, return to physical activity and complications in patients undergoing thoracoscopic and thoracotomy plication for unilateral diaphragm paralysis. In two articles by Freeman et al. (we included the surgical patients from the more recent study as it covers the time period and the patients included in the original study) [4, 5], 30 patients who had video assisted thoracoscopic surgery (VATS) diaphragmatic plication were compared with thoracotomy plication (11 patients) or non-surgical intervention (7 patients). The median length of follow-up was 57 months (range: 49–80 months). PFTs were improved in all surgical patients; and the dyspnoea score was improved in 90% of the surgical patients. In the group of patients who did not undergo surgical repair recurrent hospitalization was frequent as was loss of employment. One patient in the VATS group had a superficial wound infection (3%) and 1 patient in the thoracotomy group had a Deep Vein Thrombosis (DVT) (9%). Length of hospital stay was 1.7 days less in the VATS group.

Eight articles reported case series after thoracotomy (one was mini-thoracotomy); the total combined number of patients included in these articles was 101, although a small number of patients had bilateral plications in one series (percentage not identified). The length of follow-up in these studies ranged from 4 months to about 14 years. Ninety-seven percent of the patients had significant improvement in postoperative PFTs when compared with the preoperative PFTs; the remaining 3% had insignificant improvements. Dyspnoea score was improved in all but 4 patients (96%). Two patients reported chronic pain (2%) and 4 patients died of sepsis in the postoperative period (4%).

Three articles reported a total of 19 cases of diaphragmatic plication via VATS. The length of follow-up in these studies combined ranged from 4 months to over 2 years. All 19 patients reported improvement in their symptoms and functional status, which was correlated with the improvement noticed on the PFTs. In 3 patients undergoing ventilation perfusion scan scans, the preoperative scan demonstrated a reduction in both parameters on the affected side while postoperatively both parameters improved to approach a normal distribution [6]. One patient had a contralateral pneumonia that was treated successfully with antibiotics [7].

This work focuses mainly on the outcomes of VATS and thoracotomy approaches for diaphragmatic plication for the treatment of diaphragmatic paralysis. It is clear that PFTs will improve after the procedure but this improvement is not always correlated to clinical or functional improvements [4, 8].

Compared with thoracotomy, which can be complicated by chronic pain, DVT and longer hospital stays, a VATS approach can achieve similar results based on PFTs, dyspnoea scores and functional assessment with shorter length of stay, lower complications rate and mortality rate. Health-related quality of life (HRQOL) questionnaires have not been used to assess patients after diaphragmatic plication.

CLINICAL BOTTOM LINE

Diaphragmatic plication can improve the functional status and shortness of breath of patients with unilateral diaphragm paralysis. The series of cases undergoing VATS approach have similar results as the thoracotomy series with fewer complications. Further study on long-term benefits and HRQOL assessments are needed.

Conflict of interest: none declared..