Comparison of Mid-Term Clinical Outcomes of Different Surgical Approaches in Symptomatic Diaphragmatic Eventration

Abstract

Purpose: There is no data comparing different surgical techniques for diaphragmatic re-positioning for hemi-diaphragmatic eventration in adults. Our aim was to verify the potential pros and cons of two major surgical techniques in symptomatic eventration patients.

Methods: Patients undergoing thoracotomy for diaphragmatic elevation repair either by un-opened (accordion placation) or by opened (double-breasted placation) diaphragmatic technique between January 2007 and August 2013 were analyzed retrospectively, and compared in terms of operative outcomes on 12th and 24th months.

Results: Forty-two patients underwent accordion (n = 23) or double-breasted (n = 19) plication. Postoperative drainage was significantly increased (215 ± 66 ml vs. 114 ± 48 ml; P = 0.0082) in double-breasted group. Although the corrected diaphragm was radiologically better preserved in this group, this divergence showed no additional effect on postoperative pulmonary functions or the dyspnea score on 12th or 24th months. No complication particularly related to both techniques or recurrence was noted during follow-up of 28 ± 12 months.

Conclusions: Radiological prospect of corrected diaphragm is better preserved with double-breasted plication, but the significant and permanent improvement of respiratory functions was similar. Since the clinical outcome is equivalent, incision of the diaphragm is not essential.

Introduction

Diaphragmatic eventration is defined as long-term or constant elevation of a hemidiaphragm without presence of any anatomical defects. The etiology of diaphragmatic elevation could be the congenital eventration, with loss of muscular structure of the diaphragm and generally diagnosed in the pediatric age; or it could be acquired, secondary to phrenic nerve injury.^1–3)

The elevated diaphragm is not an uncommon radiological finding in thoracic surgery practice. The incidence of unilateral diaphragmatic elevation varies between 2.1% to 10%, but since most of the cases are asymptomatic, the precise incidence is unknown.^2,4)

Eventration and paralysis of the diaphragm are two different entities; even though they usually cause similar radiological appearance and clinical scenario. Diaphragm dysfunction typically reduces forced vital capacity (FVC) and first second forced expiratory volume (FEV₁), compatible with restrictive respiratory failure.⁴⁾ Anorexia, heartburn, constipation, and nonspecific gastrointestinal symptoms such as intermittent intestinal obstruction are often seen in pediatric patients. Postprandial epigastric discomfort, onset of tachycardia and dyspnea subsequent to food intake or exertion are usually the significant complaints of adults.^2,5,6)

Tightening of the flaccid muscle has been shown to be effective in improving pulmonary functions and reducing the symptoms by increasing the hemithoracic volume and preventing paradoxical movement on inspiration.^5–8) There are numerous surgical techniques of performing this plication via thoracotomy, grouped majorly into two on the basis of incising the diaphragm or not.^3,5,8)

The aim of the study was to objectively evaluate our postoperative outcomes and thus to compare the efficacy of two different diaphragmatic plication techniques in symptomatic adult patients.

Materials and Methods

Medical files of all symptomatic patients undergoing surgical correction for diaphragm eventration between January 2007 and August 2013 were retrospectively analyzed. Patients underwent preoperative systematic examination for the etiology of dyspnea, in order to exclude other co-morbidities such as any intra-abdominal pathology, obesity, cardiac failure, and any pulmonary disease or malignancy. Informed and written consents for each patient were obtained. Routine preoperative assessment included medical history and physical examination, radiological diagnostic tests, spirometry, and dyspnea score calculation by using Modified Medical Research Council (mMRC) dyspnea score.⁹⁾ Indication for surgical correction of the diaphragmatic elevation was made if mMRC dyspnea score was ≥2, with marked diaphragmatic elevation. Surgical diaphragmatic plication procedure was performed via thoracotomy with either the accordion technique by surgeon S.E. (A group), or with the double-breasted technique by surgeon C.T. (DB group), by opening and then plicating the diaphragm. Postoperative outcomes of both techniques in term of clinical, radiological and functional improvements were compared after 12 and 24 months. Radiological outcome was calculated by comparison of equally scaled preoperative and postoperative posteroanterior chest x-rays (Fig. 1).

Fig. 1.

Radiological comparison of pre-and-postoperative posteroanterior chest x-rays and measurement of caudal diaphragmatic shift.

Surgical technique

Intestinal emptying was achieved a day before surgery. All patients were intubated with double lumen tube. When necessary, single lung ventilation was applied. Gastric decompression was achieved by nasogastric tube. Patients were placed in lateral decubitus position and limited posterolateral thoracotomy through the 7th or 8th intercostal space was performed.

In group A, diaphragm was plicated using heavy non-absorbable sutures by “accordion” plication technique without entering the abdomen, as previously described by Schwartz and Filler.¹⁰⁾ The diaphragm is pulled in radial direction and pleats are created with full-thickness horizontal mattress fashion, using pledgets (Fig. 2a). Four to six rows are created with that “accordion” plication technique (Fig. 2b). In DB group, diaphragm was incised (Fig. 3a), the leaflets were sutured one side under the other using heavy non-absorbable sutures without any pledgets in two rows (Fig. 3b), and tightened as possible (Fig. 3c).

Fig. 2.

Schematic view of (a) suture lines and (b) completed form of accordion plication.

Fig. 3.

Schematic views of (a) incised diaphragm, (b) double-breasting of leaflets, and (c) tense diaphragm after completed plication.

Statistical analysis

Results were expressed as the mean ± the standard error, the median, and the range. Statistical analyses were performed with SPSS version 17 (IBM Corp., Armonk, NY, USA). Mann-Whitney-U and two-tailed Student’s t-test was used for comparison of variables between the two groups. The c² test was performed to detect differences in proportions between groups. P value of less than or equal to 0.05 was considered to be significant.

Results

During the study period, 42 patients with mean age of 49 ± 19 (range: 23–75) underwent surgical plication of the elevated diaphragm, either by the accordion plication (n = 23) or by the double-breasted plication (n = 19) technique. All patients were symptomatic with a minimum mMRC score of 2; suffered from either shortness of breath (n = 18), chest pain (n = 10), or both (n = 14). The hemidiaphragm was commonly elevated on the left side (33 left vs. 9 right).

In 45.2% (19/42) of the patients, the etiology of the elevation was idiopathic. For the others, the diaphragm elevation was related to trauma (33.3%; n = 14) or to surgical interventions (21.4%; n = 9). The spirometric evaluation revealed impaired preoperative FEV₁ (mean = 62% ± 8%) and FVC (mean = 61% ± 9%) values. Patient demographics, operation duration and hospital length of stay were found to be homogeneous for the two groups, and are listed in Table 1.

Table 1.

Patient demographics

	Cohort (n = 42)	Accordion group (n = 23)	Double-breasted group (n = 19)	P
Age; mean (years)	49 ± 19 (23–75)	46 ± 16	51 ± 22	0.181
Sex
Male	31	17	14	0.511
Female	11	6	5
Side
Right	9	5	4	0.481
Left	33	18	15
Etiology
Idiopathic	19 (45.2%)	10	9
Trauma	14 (33.3%)	8	6	0.197
Surgery	9 (21.4%)	5	4
Preoperative spirometry; mean
FEV1 (%)	62 ± 8 (45–79)	61 ± 10	64 ± 8	0.207
FVC (%)	61 ± 9 (42–80)	58 ± 9	66 ± 7
mMRC dyspnea score; mean	3.0 ± 0.6 (2–4)	3.1 ± 0.7	2.7 ± 0.8	0.311
Operation duration; mean (min)	66 ± 29 (38–95)	64 ± 27	69 ± 33	0.529
Total postoperative drainage; mean (ml)	142 ± 59 (50–225)	114 ± 48	215 ± 66	0.0082
Hospital stay; mean (days)	2.5 ± 0.7 (2–5)	2.3 ± 0.6	3.1 ± 0.9	0.408

FEV₁: first second forced expiratory volume; FVC: forced vital capacity; mMRC: Modified Medical Research Council

The mean radiological caudal shift in the position of diaphragm for DB and A groups was 6.3 ± 2.7 cm vs. 4.9 ± 1.9 cm in the early postoperative period (P = 0.0094), 8.3 ± 2.7 cm vs. 6.3 ± 2.0 cm in the first year (P = 0.041), and 6.1 ± 1.3 cm vs. 4.1 ± 1.4 cm (P = 0.0013) in the second year, all in favor of DB group.

Postoperative pulmonary functions and the mMRC scores of patient cohort improved significantly, but without any difference in between the both groups. Mean increase of all cohort in FEV₁ and FVC were 23% ± 8% and 24% ± 7% for 1st year, and 20% ± 8% and 21% ± 10% for 2nd year, respectively. Additionally, mean mMRC scores of all patients decreased from 3.0 ± 0.6 to 0.9 ± 0.6 in the 1st year, and to 1.2 ± 0.7 in the 2nd year (P <0.001); without significant difference between the two groups. Details of postoperative measurements are given in Table 2.

Table 2.

Postoperative follow-up

	Accordion group (n = 23)	Double-breasted group (n = 19)	P
12 months
Δ FVC (%)	23 ± 6	26 ± 7	0.751
Δ FEV1 (%)	21 ± 7	23 ± 8	0.890
mMRC dyspnea score	0.8 ± 0.7	1.0 ± 0.5	0.495
Δ caudal diaphragm shift (cm)	6.3 ± 2.0	8.3 ± 2.7	0.041
24 months
Δ FVC (%)	21 ± 6	22 ± 7	0.864
Δ FEV1 (%)	20 ± 7	22 ± 7	0.872
mMRC dyspnea score	1.2 ± 0.7	1.1 ± 0.7	0.662
Δ caudal diaphragm shift (cm)	4.1 ± 1.4	6.1 ± 1.3	0.0013

Δ: Compared to the preoperative values; FEV₁: first second forced expiratory volume; FVC: forced vital capacity; mMRC: Modified Medical Research Council

No gastrointestinal or any other postoperative complication was observed. No recurrence was seen during a mean follow-up duration of 28 ± 12 (range: 25–57) months.

Discussion

Diaphragmatic elevation is a condition that is caused by either phrenic nerve injury, so-called the paralysis of diaphragm, or congenital diaphragm eventration. Many authors indicate congenital conditions as origin of true eventration.^2,3,5) Muscular weakness, paralysis and progressive abdominal distension are the most important features of the diaphragmatic eventration.

Phrenic nerve originates from the C3-4-5 motor neurons, continues obliquely downwards into the thorax, bilaterally, and passes through the parietal pericardium before reaching the diaphragm. Therefore, any reason effecting the impulse transmission throughout the way such as tumor invasion, traumatic nerve injury, motor neuron disease, thoracic radiotherapy, or surgical complication may result in phrenic nerve dysfunction and diaphragm elevation.^1–3,6) We encountered uncommonly high incidence (33.3%) of trauma in our cohort as the primary cause of the pathology.

The diagnosis can be an incidental finding rather than a symptomatic entity. Suitable candidates for surgery are the patients with resistant complaints of dyspnea and/or thoracic pain, with objective compromised pulmonary functions. The occurrence of severe and progressive dyspnea in supine position is diagnostic for diaphragm eventration.^7,8) Patients are usually enforced to sleep in a sitting position and work consistently at an upright position. Chest x-rays are usually sufficient for documenting the pathology. Further investigation of etiology for elevated diaphragm in asymptomatic patients may be required, while it is rarely necessary in symptomatic cases. Fluoroscopy or thorax computed tomography (CT) may be useful in evaluating any subdiaphragmatic pathology contributing to diaphragmatic dysfunction or elevation.^2,3,6) In the fluoroscopy study, observing paradoxical movements of paralytic part is sufficient during deep breathing. Since it would not alter our treatment strategy, the “Sniff test” which has been used in several previous studies^2,4) was not performed in any patient.

The first successful surgical repair of the diaphragmatic eventration was reported by Morrison in 1923.¹⁾ The main purpose of the operation is repositioning the dysfunctional diaphragm: increasing the intrathoracic volume and moving the intra-abdominal organs back in place prevents mediastinal shift and paradoxical movement; thus eliminate dyspnea.^3–6) Same correction mechanism is found to be vital and life-saving in ventilatory dependent patients with uni/bilateral phrenic nerve paralysis.^2,11–14)

There are several surgical plication techniques described in literature, mainly differing by incising the diaphragm or not. The accordion and the double-breasted plication techniques are the most common transthoracic approaches used by thoracic surgeons aiming to achieve a tense and tight diaphragm.^3,6,10) Transabdominal app­roaches are also described, but have not gained much popularity.¹⁴⁾ In our study, we performed plication with and without opening the diaphragm in 19 (DB group) and 23 patients (A group), respectively.

The effectiveness of plication in patients with diaphragm elevation is well recognized in literature.^{5–8,13,15–17)} We achieved a postoperative increase over 20% both in FVC and FEV₁ measurements of our patients, which still were permanent on the second year. This improvement in pulmonary functions ensures symptomatic relief and reflects directly to the patients’ clinic. Despite significantly improved postoperative caudal shift is achieved in the position of the diaphragm with the DB technique, this difference did not have any influence on the postoperative improvement in pulmonary function test seen in both groups (Table 2). We have not performed early postoperative measurements but on the 1st and the 2nd year instead, in order to exclude any bias resulting from postoperative thoracotomy pain.

Incising the diaphragm is thought to be safer in terms of avoiding the subdiaphragmatic organs getting damaged during the plication by direct visualization.^2,6) Pros and cons of both open and closed-repairs have widely been described in literature, but separately.^{5–7,12–15,18)} We have observed significantly decreased amount of postoperative drainage in group A, with no mortality or surgery-related morbidity in both groups. This result proves the feasibility and safeness of closed-repair technique, and no need for diaphragm incision. The use of video assisted thoracoscopic surgery for diaphragm plication had lately been reported and shown to achieve similar outcome to plication via thoracotomy, which is thought to gain popularity in near future.^13,18)

Conclusion

Plication provides clinical improvement in dyspnea and functional status of patients with elevated diaphragm, regardless of plication technique or the way it is applied from. Resulting in equivalent clinical outcomes confirmed the inexpediency of incising the diaphragm. An average of 20% increase in FVC and FEV₁ values still remain on postoperative 2nd year, signifying the importance of surgery. Prospective studies with larger patient volume are required to accomplish a standard surgical approach for correction of diaphragmatic elevation in symptomatic patients.

Acknowledgement

We would like to thank Selin Başbuğ Alici for her contributions in statistical analysis, and Dr. Nurettin Yiyit for technical drawings.

Disclosure Statement

Authors state no conflict of interest of any manner.