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Pulmonary Function After Convex Thoracoplasty in Adolescent Idiopathic Scoliosis Patients Treated by Posteromedial Translation
Spine Deformity 7 (2019) 734e740 www.spine-deformity.org
Pulmonary Function After Convex Thoracoplasty in Adolescent Idiopathic Scoliosis Patients Treated by Posteromedial Translation C. Duray, MDa, E. Ferrero, MDa, F. Julien-Marsollier, MDb, A.-L. Simon, MDa, D. Michelet, MDb, K. Mazda, MDa, B. Ilharreborde, MD, PhDa,* a b
Department of Pediatric Orthopaedics, Robert Debre Hospital, AP-HP, Paris Diderot University, Bd Serurier, 75019 Paris, France Department of Pediatric Anesthesiology, Robert Debre Hospital, AP-HP, Paris Diderot University, Bd Serurier, 75019 Paris, France Received 12 June 2018; revised 6 February 2019; accepted 9 February 2019
Abstract Study design: Retrospective cohort study. Objective: To analyze the morbidity of thoracoplasty, and more specifically its effect on pulmonary function, after surgery with hybrid constructs using sublaminar bands in adolescent idiopathic scoliosis (AIS). Background: Cosmetic concern is one of the main reasons to consider surgery in adolescent idiopathic scoliosis. Several studies have demonstrated significant improvement of self-image scores after thoracoplasty. However, consequences of thoracoplasty on pulmonary function (ie, pulmonary function tests [PFTs]) remain controversial. Methods: After institutional review board approval, 96 consecutive AIS patients with thoracic curves (Lenke 1 and 2) were included between January 2014 and November 2015. All patients underwent low-dose stereoradiography with 3D reconstructions. Surgical procedure was the same in all patients: posterior correction using posteromedial translation technique with hybrid constructs (thoracic sublaminar bands and lumbar pedicle screws). Pulmonary function was explored with PFTs (forced vital capacity, forced expiratory volume in 1 second, and total lung capacity). Radiographic parameters and PFT results were compared between patients with and without thoracoplasty preoperatively and at two years postoperation. Results: Mean age was 15 2 years, and body mass index averaged 18.8 2.6. Thirty-six patients (37.5%) underwent thoracoplasty. Both groups were comparable preoperatively regarding demographic data, radiographic parameters, and PFT results. No significant difference was found between groups regarding postoperative correction rates. At the two-year follow-up, PFT results were similar to the preoperative ones and no difference was observed between groups. However, pleural effusions were reported in 26 patients (72%) on chest radiographs. Only one pleural effusion due to thoracoplasty required drainage. Conclusion: Results of the current study demonstrated that thoracoplasty associated with posteromedial translation technique did not alter PFT results at two years postoperation. The morbidity of the procedure is limited, and it can therefore be considered in patients with high cosmetic demand and significant residual rib hump after main curve correction. However, hump height and pain evaluation would be interesting data in a prospective study. Level of Evidence: Level IV. Ó 2019 Scoliosis Research Society. All rights reserved. Keywords: Adolescent idiopathic scoliosis; Thoracoplasty; Pulmonary function; Hybrid construct
Introduction Indications for adolescent idiopathic scoliosis (AIS) surgery mainly rely on Cobb angle progression, frontal Author disclosures: CD (none), EF (none), FJM (none), ALS (none), DM (none), KM (personal fees from Implanet, outside the submitted work), BI (personal fees from Implanet, Zimmer Biomet, and Medtronic, outside the submitted work). IRB approval: This study was approved by the local ethic committee number RDB-2014087.
imbalance, and reported pain. The cosmetic impact of the trunk deformity, often underestimated, plays a major role in patients’ demand, and therefore needs to be addressed. Indeed, several studies have highlighted the relationship Funding sources: none. *Corresponding author. Department of Pediatric Orthopaedics, Robert Debre Hospital, AP-HP, Diderot University, Bd Serurier, 75019 Paris, France. Tel.: þ33140033687; fax: þ33140032298. E-mail address: [email protected] (B. Ilharreborde).
2212-134X/$ - see front matter Ó 2019 Scoliosis Research Society. All rights reserved. https://doi.org/10.1016/j.jspd.2019.02.006
C. Duray et al. / Spine Deformity 7 (2019) 734e740
between patients’ outcomes, self-image perception, and rib hump measurement. Negative correlations have been reported between Scoliosis Research Societye22 (SRS-22) scores and clinical hump height, whereas thoracoplasty has been associated with significant postoperative self-image improvement [1-6]. In AIS, the rib hump is not only due to the axial rotation of the periapical vertebrae but also due to the asymmetric growth of subsequent ribs. Hence, derotating all vertebrae of the structural curve is not always sufficient to restore a symmetric rib cage, and convex ribs often remain prominent after correction. The direct vertebral derotation technique, performed with all-screw constructs, emphasizes axial correction and has been associated with 50% rib hump reduction, but at the expense of thoracic sagittal alignment [3-5,7]. Posteromedial translation has proved to restore or maintain sagittal balance but may be less effective on axial correction [8-10]. Therefore, thoracoplasty is usually discussed and proposed to patients with high cosmetic demand and preoperative rib hump O3 cm [3,6]. Studies already exist about results of thoracoplasty in AIS surgery. However, all these studies were performed with screw constructs only, and it was never assessed with posteromedial translation technique [3,11,12]. The major concern regarding thoracoplasty is the potential pulmonary function impairment. Although some authors have reported improved pulmonary function test (PFT) results in the early postoperative period, several studies demonstrated a return to normal physiological values at the two-year follow-up [3,11,12]. These controversial results may be influenced by many surgical factors, such as the number of levels fused and the technique of reduction and the amount of correction on both frontal and sagittal planes [12-14]. The aim of this study was therefore to evaluate the morbidity of convex thoracoplasty, and more specifically its effect on pulmonary function, in a series of AIS patients treated by posteromedial translation using hybrid constructs.
Materials and Methods Patients After institutional review board approval, all consecutive thoracic (Lenke 1 and 2) AIS patients operated in our department between January 2014 and November 2015 were retrospectively included. Patients with previous spinal surgery or a medical history of pulmonary disease (asthma, mucoviscidosis) were excluded. The following demographic data was collected: age, gender, and body mass index. Rib hump was assessed clinically and measured (in centimeters) at latest preoperative visit (within six months before surgery) (Fig. 1). Based on our experience, patients were informed during the preoperative visit that partial rib hump reduction (approximately 50%) would occur after main curve correction, and additional thoracoplasty was
735
Fig. 1. Clinical rib hump measurement.
proposed in case of high cosmetic concern, if patients and/ or caregivers considered that the residual hump would be too important. The risks of pleural effusion and potential higher pain level were also explained, and patients were told that they would wear a full-time brace for 2.5 months postoperatively if convex ribs were resected. Patients were evaluated preoperatively, in the early postoperative period (within four months), and at latest follow-up (minimum two years). Patients without thoracoplasty were considered as the control group. Surgical procedure All patients underwent posterior spinal fusion using hybrid constructs, associating lumbar pedicle screws (up to T11), thoracic sublaminar bands (T4eT10), and proximal supralaminar hooks, as previously described in the literature (Fig. 2) [8-10]. The main technique for thoracic correction was posteromedial translation, and additional compression/distraction maneuvers were used to level both upper (UIV) and lower (LIV) instrumented vertebrae. All procedures were performed under spinal cord monitoring. If patients asked for thoracoplasty, the convex ribs resection was performed through the same incision after main curve correction, in order to better localize the apex of the residual hump. Ribs were first dissected laterally to the spinal extensor muscles, and then subperiosteally stripped
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three times a day. Chest radiography was performed the day after surgery and at hospital discharge to look for pleural effusion. Patients started wearing brace after hospital discharge. Radiographic measurements All patients underwent low-dose biplanar radiographs (EOS-Imaging, Paris, France) in standing position, as previously described in the literature [15]. 3D reconstructions were performed using SterEOS software by a single independent experienced observer [16-18]. Radiologic measurements included Cobb angles, maximal thoracic kyphosis, maximal lumbar lordosis, and pelvic parameters. Sagittal curves were defined for each patient based on the inflection point, which is the transitional vertebra between lumbar lordosis and thoracic kyphosis [19,20]. Pulmonary function tests Pulmonary function tests were performed within six months before surgery during preoperative assessment and at two-year follow-up. In order to avoid the bias of height measurement, altered and nonreliable in scoliotic patients, PFT results were expressed using arm span as representative of height [21]. Collected parameters were forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and total lung capacity (TLC). Parameters of morbidity Pleural effusion was evaluated on chest radiographs at Days 1 and 3. In parallel, oxygen saturation was recorded three times a day. Existence of postoperative intercostal neuralgia was also collected. Statistical analysis
Fig. 2. Pre- (A, B) and postoperative (C, D) radiographs of an AIS patient treated with hybrid construct.
using a Cobb rugine from 2 cm lateral to the transverse process medially to the apex of the deformity. Neurovascular rib pedicles were bluntly dissected off the rib and remained under the periosteum. The rib segment was then cut using a Liston bone-cutting forceps and used as autologous bone for fusion. Sections were smoothed with a rongeur before closure to avoid subcutaneous conflict and covered by bone wax. In case of pleural rupture, suture was immediately performed with PDS 6-0 but no thoracic drain was used. In case of thoracoplasty, pulmonary physiotherapy was prescribed on the first postoperative day with intermittent positive pressure breathing (‘‘Bird’’) two to
Data were analyzed using Stata, version 14.0 (Statacorp LP, College Station, TX). Means and standard deviations were used to describe continuous variables, and percentages were used for categorical variables. Normal distributions of the variable were assessed using the Shapiro-Wilk Test. Demographic, radiographic, and respiratory data were compared before and after surgery within and between groups. A p value !.05 was considered significant. Results Patients and surgical procedures Ninety-six consecutive thoracic AIS patients (80 Lenke 1 and 16 Lenke 2) were included. There were 78 girls (81%) and 18 boys (19%). Age at the time of surgery averaged 15.6 2 years. Mean body mass index was 18.8 2.6 (18.3 in the thoracoplasty group and 19 in the control group, p 5 .07). Thoracoplasty was performed in 36 patients (37.5%), among which 89% were girls. Mean Cobb
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Table 1 Preoperative radiographic characteristics. Thoracoplasty group (n 5 36)
MC Cobb ( ) PC Cobb ( ) DC Cobb ( ) Lumbar lordosis ( ) Thoracic kyphosis ( ) Pelvic incidence ( ) Reducibility (%)
Control (n 5 60)
p
Mean
SD
Mean
SD
51 22 29 58 33 50 34
29 13 24 21 16 15 15
50 23 28 58 29 50 36
17 12 17 10 13 11 16
.33 .45 .17 .06 1.51 .06 .47
DC, distal curve; MC, main curve; PC, proximal curve; SD, standard deviation.
Table 2 Postoperative radiographic characteristics. Thoracoplasty group (n 5 36)
MC Cobb ( ) PC Cobb ( ) DC Cobb ( ) Lumbar lordosis ( ) Thoracic kyphosis ( )
Control (n 5 60)
p
Mean
SD
Mean
SD
21 14 9 61 42
16 11 9 10 16
22 18 7 59 36
12 11 9 11 21
.3 1.16 1.2 .9 1.4
DC, distal curve; MC, main curve; PC, proximal curve; SD, standard deviation.
angle was 51 29 in the thoracoplasty group and 50 17 in controls (p 5 .33). Thoracic kyphosis was 33 16 in the thoracoplasty group and 29 13 in the control group (p 5 1.51). Radiologic measurements are summarized in Table 1. Both groups were comparable preoperatively. Main curve correction rate was not significantly
affected by thoracoplasty (41% vs. 44%, p 5 .3). Postoperative and final coronal and sagittal radiographic measurements were not significantly different between the two groups (Table 2). The number of resected ribs averaged four (three to six), and none was resected above the lower edge of the scapula. Mean duration of thoracoplasty was 20 4 minutes. Patients who underwent thoracoplasty had the same blood transfusion rate than the control group (3% vs. 2.6%, p 5 .09). Of note, all ribs were solid at the first postoperative visit (three to four months) (Fig. 3). Complications
Fig. 3. Rib consolidation at three months postoperation. One week postoperation (A) and three months postoperation (B).
Hospitalization stay was similar in both groups (6 1.2 days for the control group and 6 1.8 days for the thoracoplasty group, p 5 .4). One pleural breach (2.7%) was noted intraoperatively during the ribs resection and repaired immediately. However, pleural effusions were frequent, reported in 26 patients (72%) on chest radiographs. Among them, 20 of the 26 patients with pleural effusion (77%) did not have any clinical respiratory symptom and the diagnosis was made on the systematic radiograph performed before discharge (Fig. 4). Six patients had moderate decreased oxygen saturation (between 90% and 95%) with significant pleural effusions (more than four ribs on radiographs; Fig. 4). All resolved spontaneously within 10 days with physiotherapy, except one patient who required pleural evacuation (drain for three days). No neurologic complication or surgical site infection was observed during the study period.
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Fig. 4. Postoperative pleural effusion. (A) Chest radiograph at Day 1; mild effusion, (B) Day 5; significant effusion, (C) Day 21. Table 3 Preoperative PFT results. Cohort
FVC (%) FEV1 (%) TLC (%)
Thoracoplasty group (n 5 36)
Control (n 5 60)
p
Mean
SD
Mean
SD
Mean
SD
86 84 83
15 15 12
84 83 83
15 15 14
87 84 84
15 14 12
.9 .2 .2
FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; PFT, pulmonary function test; SD, standard deviation; TLC, total lung capacity.
Table 4 Postoperative PFT results. Cohort
FVC (%) FEV1 (%) TLC (%)
Thoracoplasty group (n 5 36)
Control (n 5 60)
p
Mean
SD
Mean
SD
Mean
SD
86 86 85
15 16 11
83 84 83
16 15 13
87 88 85
14 16 10
1.1 .9 .6
FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; PFT, pulmonary function test; SD, standard deviation; TLC, total lung capacity.
Pulmonary function tests PFT results are reported in Tables 3 and 4. Preoperatively, 20 patients (21%) had moderate restrictive syndromes (TLC between 50% and 80%) and 3 (3%) had mild obstructive syndromes (FEV1 O 80%), without difference between groups. A trend toward PFT improvement was observed at two-year postoperative in the entire cohort (35% of the patients), but the difference did not reach significance for any of the parameter. No significant difference was found between groups in postoperative pulmonary function. Among patients who underwent thoracoplasty, 94% had similar CPT values two years postoperatively and 6% had higher ones. In the control group, 9% had higher values and 91% had similar values (p O .05). The occurrence of pleural effusion postoperatively (significant or not) did not impact significantly two years postoperative PFT results (p O .05). Discussion Cosmetic concern is one of the main reasons to consider surgery in moderate thoracic AIS (45 e65 ), but remains often underestimated in the preoperative assessment. Hence, self-image seems to be the only domain that
significantly differs between untreated AIS and healthy controls in high-level evidence literature, except for severe curves that can be associated with pulmonary restrictive syndrome. There is therefore a real correlation between patients’ expectations and the benefit of surgery that might favor fusions for moderate curves [22-24].
Why considering thoracoplasty? Rib hump can be significantly reduced with modern correction techniques, such as direct vertebral derotation (DVD) using all-screw construct or posteromedial translation. Indeed, DVD emphasizes axial correction and can provide high rates of apical rotation correction, ranging from 63% to 74% in the literature [25-27]. However, despite this efficient spinal derotation, the remaining rib prominence after DVD usually varies between 50% and 78%, mainly because of the preexisting asymmetric growth in periapical convex ribs [4]. Besides, Erkula et al. have demonstrated that the rib deformity observed in AIS is not related to either the magnitude of the Cobb angle or the amount of vertebral rotation [28]. Posteromedial translation is less effective in axial correction but optimize sagittal restoration [29]. It can therefore be considered as an
C. Duray et al. / Spine Deformity 7 (2019) 734e740
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or without thoracoplasty [3,11,12]. The current study confirmed these findings with posteromedial translation as main correction technique, using sublaminar bands, with satisfactory sagittal and coronal radiographic correction [810]. Preoperative PFT results (CPT, FEV1, and FVC) were lower than the normative value in both groups with 20% of preoperative restrictive syndromes, corresponding to the lower ranges of literature (19% to 64%) [30,31]. In our series, the adjunction of a thoracoplasty did not impact or worsen pulmonary function at the two-year follow-up compared with the control group. Another complication reported in the literature is the occurrence of intercostal neuralgia, but such complication was not observed in our series [32]. This might be explained by the careful periosteal dissection of the ribs to be resected, sparing the intercostal vessels and nerves at every level. Limitations
Fig. 5. Diminution of double rib line after thoracoplasty. (A) Postoperative and (B) preoperative.
alternative to DVD, mainly in hypokyphotic patients, and can be associated with ribs resection in case of cosmetic demand, because the literature has shown significant correlation between self-image scores and thoracoplasty (Fig. 5) [1-6].
Morbidity of thoracoplasty The major concerns regarding thoracoplasty are the risk of pleural effusion and the potential pulmonary function impairment. The rate of pleural effusion in our series was nonnegligible (72%), but respiratory symptoms remained rare. This frequent complication must therefore be explained and discussed with patients or caretakers preoperatively. Chests radiographs were systematically performed at Day 1 and 3 postoperation, and most of the effusions were absent on Day 1, but developed during the first postoperative week. They remained moderate (less than three ribs) and asymptomatic in most of the cases. Only 6% of the patients presented decreased oxygen saturation that required two more days of hospitalization on average for more intense pulmonary physiotherapy. The only case that required pleural drainage had a moderate pleural effusion at discharge, which increased during the second postoperative week. Patient was readmitted at Day 10 and the chest radiograph went back to normal after three days of drain. Previous literature has demonstrated that PFT values were back to normal at the two-year follow-up, in patients undergoing posterior fusion with all-screw constructs, with
This study presents some limitations. First, early postoperative PFT (within six months) were not performed, so the pulmonary recovery kinetic could not be assessed and compared between groups. Second, no postoperative clinical measurement of the hump was performed, so the benefit of the ribs resection cannot be objectively reported. However, the interobserver variability of rib hump measurement is large, and some surgeons in our department prefer to report the measure in centimeters whereas other ones use degrees with scoliometers. Nevertheless, there is an ongoing study assessing the satisfaction scores in patients, in which the self-image domain will be further studied. Third, postoperative pain scores were not always available in our cohort, so the influence of thoracoplasty on postoperative pain could not be evaluated. Therefore, hump height and pain evaluation would be interesting data in a prospective study. Finally, patients’ functional scores assessing self-image (SRS-30 and Spinal Appearance Questionnaire) were not used preoperatively, but they will be performed in future follow-up [33,34].
References [1] Wang L, Wang YP, Yu B, et al. Relation between self-image score of SRS-22 with deformity measures in female adolescent idiopathic scoliosis patients. Orthop Traumatol Surg Res 2014;100:797e801. [2] Bago J, Perez-Grueso FJS, Pellise F, et al. How do idiopathic scoliosis patients who improve after surgery differ from those who do not exceed a minimum detectable change? Eur Spine J 2012;21: 50e6. [3] Suk S-I, Kim J-H, Kim S-S, et al. Thoracoplasty in thoracic adolescent idiopathic scoliosis. Spine 2008;33:1061e7. [4] Samdani AF, Hwang SW, Miyanji F, et al. Direct vertebral body derotation, thoracoplasty, or both: which is better with respect to inclinometer and Scoliosis Research Society-22 scores? Spine 2012;37: E849e53. [5] Min K, Waelchli B, Hahn F. Primary thoracoplasty and pedicle screw instrumentation in thoracic idiopathic scoliosis. Eur Spine J 2005;14: 777e82.
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[6] Soultanis K, Pyrovolou N, Karamitros A, et al. The use of thoracoplasty in the surgical treatment of idiopathic scoliosis. Stud Health Technol Inform 2006;123:327e33. [7] Vora V, Crawford A, Babekhir N, et al. A pedicle screw construct gives an enhanced posterior correction of adolescent idiopathic scoliosis when compared with other constructs: myth or reality. Spine 2007;32:1869e74. [8] Mazda K, Ilharreborde B, Even J, et al. Efficacy and safety of posteromedial translation for correction of thoracic curves in adolescent idiopathic scoliosis using a new connection to the spine: the Universal Clamp. Eur Spine J 2009;18:158e69. [9] Ilharreborde B. Analyse tridimensionnelle de la correction des scolioses idiopathiques de l’adolescent par translation posteromediale. Available at: https://pastel.archives-ouvertes.fr/pastel-00736755/ document. Accessed September 3, 2017. [10] Ilharreborde B, Even J, Lefevre Y, et al. Hybrid constructs for tridimensional correction of the thoracic spine in adolescent idiopathic scoliosis: a comparative analysis of universal clamps versus hooks. Spine 2010;35:306e14. [11] Shi Z, Wu Y, Huang J, et al. Pulmonary function after thoracoplasty and posterior correction for thoracic scoliosis patients. Int J Surg Lond Engl 2013;11:1007e9. [12] Vedantam R, Lenke LG, Bridwell KH, et al. A prospective evaluation of pulmonary function in patients with adolescent idiopathic scoliosis relative to the surgical approach used for spinal arthrodesis. Spine 2000;25:82e90. [13] Newton PO, Perry A, Bastrom TP, et al. Predictors of change in postoperative pulmonary function in adolescent idiopathic scoliosis: a prospective study of 254 patients. [Miscellaneous Article]. Spine 2007;32:1875e82. [14] Lenke LG, Bridwell KH, Blanke K, et al. Analysis of pulmonary function and chest cage dimension changes after thoracoplasty in idiopathic scoliosis. Spine 1995;20:1343e50. [15] Ilharreborde B, Sebag G, Skalli W, et al. Adolescent idiopathic scoliosis treated with posteromedial translation: radiologic evaluation with a 3D low-dose system. Eur Spine J 2013;22:2382e91. [16] Ilharreborde B, Steffen JS, Nectoux E, et al. Angle measurement reproducibility using EOS three-dimensional reconstructions in adolescent idiopathic scoliosis treated by posterior instrumentation. Spine 2011;36:E1306e13. [17] Baudoin A, Mitton D, Skalli W. An accurate pelvis axis system using a low dose x-ray device. In: Paper presented at: 6th Annual Conference of the International Society for Computer Assisted Orthopaedic Surgery 2006. Montreal, Quebec. [18] Sangole A, Aubin C-E, Labelle H, et al. The central hip vertical axis: a reference axis for the Scoliosis Research Society three-dimensional classification of idiopathic scoliosis. Spine 2010;35:E530e4.
[19] Roussouly P, Pinheiro-Franco JL. Sagittal parameters of the spine: biomechanical approach. Eur Spine J 2011;20(Suppl 5):578e85. [20] Roussouly P, Gollogly S, Berthonnaud E, et al. Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position. Spine 2005;30:346e53. [21] Parker JM, Dillard TA, Phillips YY. Arm span-height relationships in patients referred for spirometry. Am J Respir Crit Care Med 1996;154:533e6. [22] Rushton PR, Grevitt MP. Comparison of untreated adolescent idiopathic scoliosis with normal controls: a review and statistical analysis of the literature. Spine (Phila Pa 1976) 2013;38:778e85. [23] Yaszay B, Bastrom TP, Bartley CE, et al. The effects of the threedimensional deformity of adolescent idiopathic scoliosis on pulmonary function. Eur Spine J 2017;26:1658e64. [24] Ward WT, Friel NA, Kenkre TS, et al. SRS-22r scores in nonoperated adolescent idiopathic scoliosis patients with curves greater than forty degrees. Spine (Phila Pa 1976) 2017;42:1233e40. [25] Kadoury S, Cheriet F, Beausejour M, et al. A three-dimensional retrospective analysis of the evolution of spinal instrumentation for the correction of adolescent idiopathic scoliosis. Eur Spine J 2009;18:23e37. [26] Di Silvestre M, Lolli F, Bakaloudis G, et al. Apical vertebral derotation in the posterior treatment of adolescent idiopathic scoliosis: myth or reality? Eur Spine J 2013;22:313e23. [27] Seoud L, Cheriet F, Labelle H, Parent S. Changes in trunk appearance after scoliosis spinal surgery and their relation to changes in spinal measurements. Spine Deform 2015;3:595e603. [28] Erkula G, Sponseller PD, Kiter AE. Rib deformity in scoliosis. Eur Spine J 2003;12:281e7. [29] Ilharreborde B. Sagittal balance and idiopathic scoliosis: does final sagittal alignment influence outcomes, degeneration rate or failure rate? Eur Spine J 2018;27:48e58. [30] Saraiva BMA, Araujo GS, Sperandio EF, et al. Impact of scoliosis severity on functional capacity in patients with adolescent idiopathic scoliosis. Pediatr Exerc Sci 2018;30:243e50. [31] Johnston CE, Richards BS, Sucato DJ, et al. Correlation of preoperative deformity magnitude and pulmonary function tests in adolescent idiopathic scoliosis. Spine 2011;36:1096e102. [32] Yang JH, Bhandarkar AW, Modi HN, et al. Short apical rib resections thoracoplasty compared to conventional thoracoplasty in adolescent idiopathic scoliosis surgery. Eur Spine J 2014;23:2680e8. [33] Ghandehari H, Mahabadi MA, Mahdavi SM, et al. Evaluation of patient outcome and satisfaction after surgical treatment of adolescent idiopathic scoliosis using Scoliosis Research Society-30. Arch Bone Jt Surg 2015;3:109e13. [34] Carreon LY, Sanders JO, Polly DW, et al. Spinal appearance questionnaire: factor analysis, scoring, reliability, and validity testing. Spine 2011;36:E1240e4.
Pulmonary Function After Convex Thoracoplasty in Adolescent Idiopathic Scoliosis Patients Treated by Posteromedial Translation C. Duray, MDa, E. Ferrero, MDa, F. Julien-Marsollier, MDb, A.-L. Simon, MDa, D. Michelet, MDb, K. Mazda, MDa, B. Ilharreborde, MD, PhDa,* a b
Department of Pediatric Orthopaedics, Robert Debre Hospital, AP-HP, Paris Diderot University, Bd Serurier, 75019 Paris, France Department of Pediatric Anesthesiology, Robert Debre Hospital, AP-HP, Paris Diderot University, Bd Serurier, 75019 Paris, France Received 12 June 2018; revised 6 February 2019; accepted 9 February 2019
Abstract Study design: Retrospective cohort study. Objective: To analyze the morbidity of thoracoplasty, and more specifically its effect on pulmonary function, after surgery with hybrid constructs using sublaminar bands in adolescent idiopathic scoliosis (AIS). Background: Cosmetic concern is one of the main reasons to consider surgery in adolescent idiopathic scoliosis. Several studies have demonstrated significant improvement of self-image scores after thoracoplasty. However, consequences of thoracoplasty on pulmonary function (ie, pulmonary function tests [PFTs]) remain controversial. Methods: After institutional review board approval, 96 consecutive AIS patients with thoracic curves (Lenke 1 and 2) were included between January 2014 and November 2015. All patients underwent low-dose stereoradiography with 3D reconstructions. Surgical procedure was the same in all patients: posterior correction using posteromedial translation technique with hybrid constructs (thoracic sublaminar bands and lumbar pedicle screws). Pulmonary function was explored with PFTs (forced vital capacity, forced expiratory volume in 1 second, and total lung capacity). Radiographic parameters and PFT results were compared between patients with and without thoracoplasty preoperatively and at two years postoperation. Results: Mean age was 15 2 years, and body mass index averaged 18.8 2.6. Thirty-six patients (37.5%) underwent thoracoplasty. Both groups were comparable preoperatively regarding demographic data, radiographic parameters, and PFT results. No significant difference was found between groups regarding postoperative correction rates. At the two-year follow-up, PFT results were similar to the preoperative ones and no difference was observed between groups. However, pleural effusions were reported in 26 patients (72%) on chest radiographs. Only one pleural effusion due to thoracoplasty required drainage. Conclusion: Results of the current study demonstrated that thoracoplasty associated with posteromedial translation technique did not alter PFT results at two years postoperation. The morbidity of the procedure is limited, and it can therefore be considered in patients with high cosmetic demand and significant residual rib hump after main curve correction. However, hump height and pain evaluation would be interesting data in a prospective study. Level of Evidence: Level IV. Ó 2019 Scoliosis Research Society. All rights reserved. Keywords: Adolescent idiopathic scoliosis; Thoracoplasty; Pulmonary function; Hybrid construct
Introduction Indications for adolescent idiopathic scoliosis (AIS) surgery mainly rely on Cobb angle progression, frontal Author disclosures: CD (none), EF (none), FJM (none), ALS (none), DM (none), KM (personal fees from Implanet, outside the submitted work), BI (personal fees from Implanet, Zimmer Biomet, and Medtronic, outside the submitted work). IRB approval: This study was approved by the local ethic committee number RDB-2014087.
imbalance, and reported pain. The cosmetic impact of the trunk deformity, often underestimated, plays a major role in patients’ demand, and therefore needs to be addressed. Indeed, several studies have highlighted the relationship Funding sources: none. *Corresponding author. Department of Pediatric Orthopaedics, Robert Debre Hospital, AP-HP, Diderot University, Bd Serurier, 75019 Paris, France. Tel.: þ33140033687; fax: þ33140032298. E-mail address: [email protected] (B. Ilharreborde).
2212-134X/$ - see front matter Ó 2019 Scoliosis Research Society. All rights reserved. https://doi.org/10.1016/j.jspd.2019.02.006
C. Duray et al. / Spine Deformity 7 (2019) 734e740
between patients’ outcomes, self-image perception, and rib hump measurement. Negative correlations have been reported between Scoliosis Research Societye22 (SRS-22) scores and clinical hump height, whereas thoracoplasty has been associated with significant postoperative self-image improvement [1-6]. In AIS, the rib hump is not only due to the axial rotation of the periapical vertebrae but also due to the asymmetric growth of subsequent ribs. Hence, derotating all vertebrae of the structural curve is not always sufficient to restore a symmetric rib cage, and convex ribs often remain prominent after correction. The direct vertebral derotation technique, performed with all-screw constructs, emphasizes axial correction and has been associated with 50% rib hump reduction, but at the expense of thoracic sagittal alignment [3-5,7]. Posteromedial translation has proved to restore or maintain sagittal balance but may be less effective on axial correction [8-10]. Therefore, thoracoplasty is usually discussed and proposed to patients with high cosmetic demand and preoperative rib hump O3 cm [3,6]. Studies already exist about results of thoracoplasty in AIS surgery. However, all these studies were performed with screw constructs only, and it was never assessed with posteromedial translation technique [3,11,12]. The major concern regarding thoracoplasty is the potential pulmonary function impairment. Although some authors have reported improved pulmonary function test (PFT) results in the early postoperative period, several studies demonstrated a return to normal physiological values at the two-year follow-up [3,11,12]. These controversial results may be influenced by many surgical factors, such as the number of levels fused and the technique of reduction and the amount of correction on both frontal and sagittal planes [12-14]. The aim of this study was therefore to evaluate the morbidity of convex thoracoplasty, and more specifically its effect on pulmonary function, in a series of AIS patients treated by posteromedial translation using hybrid constructs.
Materials and Methods Patients After institutional review board approval, all consecutive thoracic (Lenke 1 and 2) AIS patients operated in our department between January 2014 and November 2015 were retrospectively included. Patients with previous spinal surgery or a medical history of pulmonary disease (asthma, mucoviscidosis) were excluded. The following demographic data was collected: age, gender, and body mass index. Rib hump was assessed clinically and measured (in centimeters) at latest preoperative visit (within six months before surgery) (Fig. 1). Based on our experience, patients were informed during the preoperative visit that partial rib hump reduction (approximately 50%) would occur after main curve correction, and additional thoracoplasty was
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Fig. 1. Clinical rib hump measurement.
proposed in case of high cosmetic concern, if patients and/ or caregivers considered that the residual hump would be too important. The risks of pleural effusion and potential higher pain level were also explained, and patients were told that they would wear a full-time brace for 2.5 months postoperatively if convex ribs were resected. Patients were evaluated preoperatively, in the early postoperative period (within four months), and at latest follow-up (minimum two years). Patients without thoracoplasty were considered as the control group. Surgical procedure All patients underwent posterior spinal fusion using hybrid constructs, associating lumbar pedicle screws (up to T11), thoracic sublaminar bands (T4eT10), and proximal supralaminar hooks, as previously described in the literature (Fig. 2) [8-10]. The main technique for thoracic correction was posteromedial translation, and additional compression/distraction maneuvers were used to level both upper (UIV) and lower (LIV) instrumented vertebrae. All procedures were performed under spinal cord monitoring. If patients asked for thoracoplasty, the convex ribs resection was performed through the same incision after main curve correction, in order to better localize the apex of the residual hump. Ribs were first dissected laterally to the spinal extensor muscles, and then subperiosteally stripped
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three times a day. Chest radiography was performed the day after surgery and at hospital discharge to look for pleural effusion. Patients started wearing brace after hospital discharge. Radiographic measurements All patients underwent low-dose biplanar radiographs (EOS-Imaging, Paris, France) in standing position, as previously described in the literature [15]. 3D reconstructions were performed using SterEOS software by a single independent experienced observer [16-18]. Radiologic measurements included Cobb angles, maximal thoracic kyphosis, maximal lumbar lordosis, and pelvic parameters. Sagittal curves were defined for each patient based on the inflection point, which is the transitional vertebra between lumbar lordosis and thoracic kyphosis [19,20]. Pulmonary function tests Pulmonary function tests were performed within six months before surgery during preoperative assessment and at two-year follow-up. In order to avoid the bias of height measurement, altered and nonreliable in scoliotic patients, PFT results were expressed using arm span as representative of height [21]. Collected parameters were forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and total lung capacity (TLC). Parameters of morbidity Pleural effusion was evaluated on chest radiographs at Days 1 and 3. In parallel, oxygen saturation was recorded three times a day. Existence of postoperative intercostal neuralgia was also collected. Statistical analysis
Fig. 2. Pre- (A, B) and postoperative (C, D) radiographs of an AIS patient treated with hybrid construct.
using a Cobb rugine from 2 cm lateral to the transverse process medially to the apex of the deformity. Neurovascular rib pedicles were bluntly dissected off the rib and remained under the periosteum. The rib segment was then cut using a Liston bone-cutting forceps and used as autologous bone for fusion. Sections were smoothed with a rongeur before closure to avoid subcutaneous conflict and covered by bone wax. In case of pleural rupture, suture was immediately performed with PDS 6-0 but no thoracic drain was used. In case of thoracoplasty, pulmonary physiotherapy was prescribed on the first postoperative day with intermittent positive pressure breathing (‘‘Bird’’) two to
Data were analyzed using Stata, version 14.0 (Statacorp LP, College Station, TX). Means and standard deviations were used to describe continuous variables, and percentages were used for categorical variables. Normal distributions of the variable were assessed using the Shapiro-Wilk Test. Demographic, radiographic, and respiratory data were compared before and after surgery within and between groups. A p value !.05 was considered significant. Results Patients and surgical procedures Ninety-six consecutive thoracic AIS patients (80 Lenke 1 and 16 Lenke 2) were included. There were 78 girls (81%) and 18 boys (19%). Age at the time of surgery averaged 15.6 2 years. Mean body mass index was 18.8 2.6 (18.3 in the thoracoplasty group and 19 in the control group, p 5 .07). Thoracoplasty was performed in 36 patients (37.5%), among which 89% were girls. Mean Cobb
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Table 1 Preoperative radiographic characteristics. Thoracoplasty group (n 5 36)
MC Cobb ( ) PC Cobb ( ) DC Cobb ( ) Lumbar lordosis ( ) Thoracic kyphosis ( ) Pelvic incidence ( ) Reducibility (%)
Control (n 5 60)
p
Mean
SD
Mean
SD
51 22 29 58 33 50 34
29 13 24 21 16 15 15
50 23 28 58 29 50 36
17 12 17 10 13 11 16
.33 .45 .17 .06 1.51 .06 .47
DC, distal curve; MC, main curve; PC, proximal curve; SD, standard deviation.
Table 2 Postoperative radiographic characteristics. Thoracoplasty group (n 5 36)
MC Cobb ( ) PC Cobb ( ) DC Cobb ( ) Lumbar lordosis ( ) Thoracic kyphosis ( )
Control (n 5 60)
p
Mean
SD
Mean
SD
21 14 9 61 42
16 11 9 10 16
22 18 7 59 36
12 11 9 11 21
.3 1.16 1.2 .9 1.4
DC, distal curve; MC, main curve; PC, proximal curve; SD, standard deviation.
angle was 51 29 in the thoracoplasty group and 50 17 in controls (p 5 .33). Thoracic kyphosis was 33 16 in the thoracoplasty group and 29 13 in the control group (p 5 1.51). Radiologic measurements are summarized in Table 1. Both groups were comparable preoperatively. Main curve correction rate was not significantly
affected by thoracoplasty (41% vs. 44%, p 5 .3). Postoperative and final coronal and sagittal radiographic measurements were not significantly different between the two groups (Table 2). The number of resected ribs averaged four (three to six), and none was resected above the lower edge of the scapula. Mean duration of thoracoplasty was 20 4 minutes. Patients who underwent thoracoplasty had the same blood transfusion rate than the control group (3% vs. 2.6%, p 5 .09). Of note, all ribs were solid at the first postoperative visit (three to four months) (Fig. 3). Complications
Fig. 3. Rib consolidation at three months postoperation. One week postoperation (A) and three months postoperation (B).
Hospitalization stay was similar in both groups (6 1.2 days for the control group and 6 1.8 days for the thoracoplasty group, p 5 .4). One pleural breach (2.7%) was noted intraoperatively during the ribs resection and repaired immediately. However, pleural effusions were frequent, reported in 26 patients (72%) on chest radiographs. Among them, 20 of the 26 patients with pleural effusion (77%) did not have any clinical respiratory symptom and the diagnosis was made on the systematic radiograph performed before discharge (Fig. 4). Six patients had moderate decreased oxygen saturation (between 90% and 95%) with significant pleural effusions (more than four ribs on radiographs; Fig. 4). All resolved spontaneously within 10 days with physiotherapy, except one patient who required pleural evacuation (drain for three days). No neurologic complication or surgical site infection was observed during the study period.
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Fig. 4. Postoperative pleural effusion. (A) Chest radiograph at Day 1; mild effusion, (B) Day 5; significant effusion, (C) Day 21. Table 3 Preoperative PFT results. Cohort
FVC (%) FEV1 (%) TLC (%)
Thoracoplasty group (n 5 36)
Control (n 5 60)
p
Mean
SD
Mean
SD
Mean
SD
86 84 83
15 15 12
84 83 83
15 15 14
87 84 84
15 14 12
.9 .2 .2
FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; PFT, pulmonary function test; SD, standard deviation; TLC, total lung capacity.
Table 4 Postoperative PFT results. Cohort
FVC (%) FEV1 (%) TLC (%)
Thoracoplasty group (n 5 36)
Control (n 5 60)
p
Mean
SD
Mean
SD
Mean
SD
86 86 85
15 16 11
83 84 83
16 15 13
87 88 85
14 16 10
1.1 .9 .6
FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; PFT, pulmonary function test; SD, standard deviation; TLC, total lung capacity.
Pulmonary function tests PFT results are reported in Tables 3 and 4. Preoperatively, 20 patients (21%) had moderate restrictive syndromes (TLC between 50% and 80%) and 3 (3%) had mild obstructive syndromes (FEV1 O 80%), without difference between groups. A trend toward PFT improvement was observed at two-year postoperative in the entire cohort (35% of the patients), but the difference did not reach significance for any of the parameter. No significant difference was found between groups in postoperative pulmonary function. Among patients who underwent thoracoplasty, 94% had similar CPT values two years postoperatively and 6% had higher ones. In the control group, 9% had higher values and 91% had similar values (p O .05). The occurrence of pleural effusion postoperatively (significant or not) did not impact significantly two years postoperative PFT results (p O .05). Discussion Cosmetic concern is one of the main reasons to consider surgery in moderate thoracic AIS (45 e65 ), but remains often underestimated in the preoperative assessment. Hence, self-image seems to be the only domain that
significantly differs between untreated AIS and healthy controls in high-level evidence literature, except for severe curves that can be associated with pulmonary restrictive syndrome. There is therefore a real correlation between patients’ expectations and the benefit of surgery that might favor fusions for moderate curves [22-24].
Why considering thoracoplasty? Rib hump can be significantly reduced with modern correction techniques, such as direct vertebral derotation (DVD) using all-screw construct or posteromedial translation. Indeed, DVD emphasizes axial correction and can provide high rates of apical rotation correction, ranging from 63% to 74% in the literature [25-27]. However, despite this efficient spinal derotation, the remaining rib prominence after DVD usually varies between 50% and 78%, mainly because of the preexisting asymmetric growth in periapical convex ribs [4]. Besides, Erkula et al. have demonstrated that the rib deformity observed in AIS is not related to either the magnitude of the Cobb angle or the amount of vertebral rotation [28]. Posteromedial translation is less effective in axial correction but optimize sagittal restoration [29]. It can therefore be considered as an
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or without thoracoplasty [3,11,12]. The current study confirmed these findings with posteromedial translation as main correction technique, using sublaminar bands, with satisfactory sagittal and coronal radiographic correction [810]. Preoperative PFT results (CPT, FEV1, and FVC) were lower than the normative value in both groups with 20% of preoperative restrictive syndromes, corresponding to the lower ranges of literature (19% to 64%) [30,31]. In our series, the adjunction of a thoracoplasty did not impact or worsen pulmonary function at the two-year follow-up compared with the control group. Another complication reported in the literature is the occurrence of intercostal neuralgia, but such complication was not observed in our series [32]. This might be explained by the careful periosteal dissection of the ribs to be resected, sparing the intercostal vessels and nerves at every level. Limitations
Fig. 5. Diminution of double rib line after thoracoplasty. (A) Postoperative and (B) preoperative.
alternative to DVD, mainly in hypokyphotic patients, and can be associated with ribs resection in case of cosmetic demand, because the literature has shown significant correlation between self-image scores and thoracoplasty (Fig. 5) [1-6].
Morbidity of thoracoplasty The major concerns regarding thoracoplasty are the risk of pleural effusion and the potential pulmonary function impairment. The rate of pleural effusion in our series was nonnegligible (72%), but respiratory symptoms remained rare. This frequent complication must therefore be explained and discussed with patients or caretakers preoperatively. Chests radiographs were systematically performed at Day 1 and 3 postoperation, and most of the effusions were absent on Day 1, but developed during the first postoperative week. They remained moderate (less than three ribs) and asymptomatic in most of the cases. Only 6% of the patients presented decreased oxygen saturation that required two more days of hospitalization on average for more intense pulmonary physiotherapy. The only case that required pleural drainage had a moderate pleural effusion at discharge, which increased during the second postoperative week. Patient was readmitted at Day 10 and the chest radiograph went back to normal after three days of drain. Previous literature has demonstrated that PFT values were back to normal at the two-year follow-up, in patients undergoing posterior fusion with all-screw constructs, with
This study presents some limitations. First, early postoperative PFT (within six months) were not performed, so the pulmonary recovery kinetic could not be assessed and compared between groups. Second, no postoperative clinical measurement of the hump was performed, so the benefit of the ribs resection cannot be objectively reported. However, the interobserver variability of rib hump measurement is large, and some surgeons in our department prefer to report the measure in centimeters whereas other ones use degrees with scoliometers. Nevertheless, there is an ongoing study assessing the satisfaction scores in patients, in which the self-image domain will be further studied. Third, postoperative pain scores were not always available in our cohort, so the influence of thoracoplasty on postoperative pain could not be evaluated. Therefore, hump height and pain evaluation would be interesting data in a prospective study. Finally, patients’ functional scores assessing self-image (SRS-30 and Spinal Appearance Questionnaire) were not used preoperatively, but they will be performed in future follow-up [33,34].
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