Correction of pectus excavatum using a sternal elevator: preliminary report

Transcription

1 British Journal of Plastic Surgery (2001), 54, The British Association of Plastic Surgeons doi: /bjps BR 'r SH JO[J RI~A/ OF ~ PIAST C su RG~'Y 1 Correction of pectus excavatum using a sternal elevator: preliminary report K. Onishi and Y. Maruyama Department of Plastic and Reconstructive Surgery, Toho University Hospital, Tokyo, Japan SUMMARY. Operative procedures to correct the deformity caused by pectus excavatum are generally based on either sternal elevation or turnover. In either case, the is highly invasive. By considering the softness of the costal cartilages in early childhood, we have developed an endoscopically assisted procedure that applies external traction continuously in order to elevate the depressed sternum and costal cartilages. Since August 1993, we have performed this in 11 patients with pectus excavatum who ranged in age from 3 years 1 month to 28 years. The traction screws came loose spontaneously in two early cases. Augmentation transfer of a latissimus dorsi muscle flap and dermal fat grafting were subsequently performed in these two patients, respectively. We achieved an excellent cosmetic outcome in the other nine patients, with results similar to those achieved with the conventional. Our technique is a two-stage procedure and the patient is limited in performing daily activities while wearing the traction device. Despite this drawback it can achieve permanent correction of the deformity. Accordingly, this method should be considered when pectus excavatum is corrected surgically, particularly in infants and young children The British Association of Plastic Surgeons Keywords: pectus excavatum, sternal elevator, funnel chest, sternum, costal cartilage. Pectus excavatum is not usually associated with cardiopulmonary dysfunction severe enough to affect daily life. Accordingly, surgery is often performed for cosmetic improvement and to prevent psychological problems in the patient and family. Conventional surgical procedures for the correction of this deformity fall into two major categories, namely sternal elevation and turnover. Although numerous modifications have been reported for both of these procedures, the always involves exposure of the sternum and costal cartilages by dissection from the surrounding tissues, resection and division of the costal cartilages and osteotomy of the stemum. Thus, the procedure involves extensive exposure and scarring and better alternatives are sought. We have devised a method for correction of the deformity by applying continuous traction to the sternum and costal cartilages using an external device, which requires minimal surgical intervention to expose the relevant structures and divide and resect the costal cartilages. We designed this procedure to take advantage of the plasticity of the costal cartilages in infants and young children. In order to achieve a better cosmetic outcome, we use an endoscope to minimise the operative scarring. Although this procedure has been used in only a few patients and we do not yet have long-term follow-up, we would like to outline the method in this preliminary report. Materials and methods Operative instruments Operative instruments for both open surgery and endoscopic surgery are required. Rigid endoscopes with Presented at the 42nd Annual Meeting of the Japanese Society of Plastic and Reconstructive Surgery, Fukuoka, Japan, 21 April internal diameters of 4 mm and 10 mm are used for paediatric and adult patients, respectively. These endoscopes can provide forward and 30~ vision. The endoscope is mounted on a retractor. The retractor is held with one hand to secure the operative field and surgery is performed with the other hand. When both hands are needed, the endoscope and retractor are held in position with support arms (Fig. 1).1'2 A long-handled electrosurgical blade, suction tube, retractor and long-handled bone saws with short angled blades are used, as well as forceps, dissectors and scissors for endoscopic surgery. The suction tube is required to remove smoke generated by the electrosurgical blade and is useful for keeping the endoscopic field clear. Sternal elevator An original elevator design was developed for this procedure. The device has an H-shaped body that supports the traction screws, four legs with cushions that contact the chest wall and two traction screws that are inserted into the sternum for traction (TM Sternal Elevator, Taguchi Medical Company, Tokyo, Japan) (Fig. 2). The original elevator used in our early cases has been repeatedly modified. At present, large and small elevators are available. The elevator is made of titanium so as to minimise its weight. To prevent pressure sores, soft felt cushions are placed at the points of contact with the chest wall. The cushions and the four legs are connected by loose fasteners so it is easy to assemble them. In addition, screws are used to connect the legs to the elevator body so that the position of the legs can be adjusted freely to avoid leaving the cushions continuously on the same area of chest skin. The traction screw inserted into the sternum for extemal traction has three parts, a traction hook, a hook stopper 117

2 118 British Journal of Plastic Surgery Figure 3--The traction screw inserted into the stemum has three parts: (A) traction hook, (B) hook stopper and (C) elevator grip. Figure 1---Endoscopic dissection using a support ann that holds the endoscope. Figure 4---Schematic diagram of extemal traction using the traction screw. (A) A hole is drilled into the body of the sternum. (B) A traction hook is inserted to the hole. (C) A hook stopper is attached to the traction hook. (D) When the hook stopper is rotated, the tip of the traction hook can bend through up to 90~ (E) Once the sternum is supported with the hook, an elevator grip is attached to the hook stopper.with one turn of the elevator grip, the length of the traction screw is reduced by 1.5mm. the hook stopper is turned back, the tip of the hook is straightened and it can be extracted manually. Operative procedure Figure 2---The original-design TM Sternal Elevator has an H-shaped body with traction screws for traction, four legs with cushions that contact the chest wall and two traction screws that are inserted into the sternum. and an elevator grip (Figs 3 and 4). The traction hook, which is inserted into the stemum, measures 4 m m in diameter. When the hook stopper is rotated, the tip o f the traction hook can be bent through up to 90 ~ and thus supports the undersurface of the sternum. After the stemum has been supported with the hooks, an elevator grip is attached to each screw and the sternum is elevated by traction. With one tum of the elevator grip, the length of the screw is reduced by 1.5 mm, generating continuous traction on the stemum. The screws are made of titanium so that removal is easy and granulation tissue does not form because there is no firm union with the bone. W h e n The patient is placed in the supine position. Both upper limbs are laid beside the trunk so as to avoid tension in the skin o f the anterior chest wall and to facilitate surgery over a wide area under direct vision through a small incision. A 3-4 cm midline incision is made, with the lower end of the xiphoid process at the centre of the incision. To prevent skin damage from retractors and other instruments, the margin of the incision is wrapped with a segment o f silicone tube cut longitudinally and fixed by sutures (Fig. 5). Under direct vision, the superficial surface o f the sternum and the costal cartilages are dissected from the surrounding tissues. The skin incision, although small, can be moved in all directions enabling exposure of a considerable area o f the sternum and costal cartilages. Subsequently, the insertion of the rectus abdominis muscle is detached and freed from the costal cartilages. The xiphoid process is divided from the sternum at its

3 Correction of pectus excavatum with sternal elevator 119 Figure 7--After insertion of the traction screws, the tip of each screw is bent through 90 ~ to support the sternum (endoscopic view). Figure 5--To prevent skin damage, the margin of the incision is wrapped with a segment of silicone tube cut longitudinally and fixed with sutures (endoscopic view). Figure ~-Endoscopic anterior osteotomy of the sternum is performed with an angled bone saw, leaving the posterior cortex uncut. base, with the rectus abdominis muscle attached to it. Then, the undersurface of the sternum and the costal cartilages are dissected from the pleura; when this process cannot be continued under direct vision, an endoscope is inserted and the proceeds endoscopically. Under endoscopic vision, the superficial surface and undersurface of the sternum and the costal cartilages are dissected from the adjacent tissues. Dissection should be kept to a minimum. With a retractor placed beneath the undersurface of the sternum to protect the pleura, endoscopic anterior osteotomy of the sternum is performed between the second and third intercostal spaces with a bone saw, leaving the posterior cortex uncut (Fig. 6). The sternum is then divided when a greenstick fracture is produced by raising its lower end. The perichondria of the deformed third to eighth costal cartilages are incised at the lateral side of the sternum, the medial border of the costochondral junction or between them, and dissected anteriorly over about half of the circumference. Additional anterior incisions or wedge-shaped resections of the costal cartilages are performed until the sternum can be elevated to the correct position when the lower end is raised. The posterior parts of the costal cartilages with the perichondrium intact are mobilised by creating greenstick fractures. Additional incisions or resection of the costal cartilages can be performed if necessary, depending on the extent and nature of the deformity of the thoracic cage. With a retractor beneath the undersurface of the sternum to protect the pleura, two holes are drilled in the body of the sternum through skin incisions of about 5 mm in diameter for insertion of the two traction screws. After insertion of the traction screws, the tip of each screw is bent through 90 ~ to support the sternum. These procedures are performed under endoscopic vision (Fig. 7). The traction screws are then connected to the body of the traction device. After completion of haemostasis under endoscopic vision, a suction drain is placed beneath the sternum. Before wound closure, the incisions in the perichondrium are repaired as completely as possible with sutures. The xiphoid process is sutured to the lower end of the sternum to prevent postoperative bulging of the upper abdomen. Soon after the, the sternum is elevated by traction to as close as possible to the target position. After the patient is discharged from hospital, traction is maintained by adjusting the screws as necessary for additional elevation during weekly or biweekly follow-up visits. The cushions in contact with the chest skin should be moved frequently so as to avoid pressure sores. When the sternum has been elevated to the correct position and the result has been monitored for about a month, the traction screws are removed. The margins of the traction-screw wounds are trimmed and closed with sutures. Local anaesthesia can be used for screw removal in older patients. Results Since August 1993, we have performed this on 11 patients with pectus excavatum (Table 1). The was performed with full informed consent and permission from the Hospital Ethics Committee was not required. At the time of surgery, the 11 patients (10 males and one female) ranged in age from 3 years 1 month to 28 years (seven were younger than 10 years, three were aged between 11 and 20 years and one was older than 20 years). The lasted between 2h 5 min and 9h 30rain, with a mean time of 4h 2min. In the seven patients less than 10 years old, the lasted on average 3 h 21 min. Removal of the traction screws took between 13 and 47 rain, with a mean time of 29 min. The removal procedure usually required hospital admission for 3 days and general anaesthesia, but was performed under local anaesthesia in two older patients. The traction screws were spontaneously extruded in two patients (cases 1 and 4). These two patients received an augmentation transfer of a latissimus dorsi muscle flap and dermal fat grafts from the buttock, respectively, because correction by traction alone was insufficient. In case 7, one of the two traction screws was spontaneously extruded but external traction was continued using the remaining screw until the sternum was elevated to the target position. Based on our experience with cases 1 and 4, the design of the traction screw was modified and the modified screw was found to be more effective. The duration of traction ranged from 61 days to 122 days

4 Results Follow-up after the second (months) fair fair Table 1 Details of the cases Case Age Sex number (years) Duration of first Blood loss during first (ml) Hospital stay after first (days) Period of elevation (days) Duration of second (min) Complications Additional s 1 6 M 2 6 F 3 15 M 4 3 M 5 18 M 6 13 M 7 4 M 8 5 M 9 3 M M 11 4 M 4h 10min 2h 35min 4h 30min 2 h 5 min 4h 35 min 2h 15min 3h 27min 4h 40min 3h 45min 9h 30min 2h 47min * * 18 two screws came out emphysematous bulla two screws came out one screw came out latissimus dorsi muscle flap augmentation removal of bulla dermal-fat augmentation * Local anaesthesia.

5 Correction of pectus excavatum with sternal elevator 121 (mean: 87 days) in nine patients (excluding cases 1 and 4). The duration of traction in the later cases was shorter than in the early cases. Hospital stay for the first was also shorter in the later cases. In case 3, a rightsided pneumothorax occurred postoperatively. Despite continuous chest drainage, there was no improvement. An emphysematous bulla was detected at the apex of the lung and removed by thoracoscopic surgery. None of the other patients had any complications. The patients have been followed up for between 5 months and 5 years 8 months after completion of traction, with a mean of 3 years 7 months. The cosmetic results are satisfactory. More than 1 year has passed since removal of the traction screws in 10 patients. In these patients, the pectus excavatum indices before and after the were calculated according to the method described by Hoshi based on transverse CT scans at the level of the lower end of the sternum (Table 2, Fig. 8). 3 The mean value of the depression index (D), which represents the improvement in depression of the thoracic cage, increased from _ before surgery to _ postoperatively. The mean value of the chest-shape index (C), which is the ratio of the width to the anteroposterior diameter of the thoracic cage and is useful for comparison with the normal thorax, also improved postoperatively, increasing from 0.518_ to 0.626_ Hoshi measured various indices in 100 normal persons and the mean values were as follows: depression index (D) 1.004_+0.020; symmetry index (S) 0.986_+0.018; flatness index (F) 0.681_+0.043; deformed-width index (W) 0_+0; and chest-shape index (C) _ He also calculated these indices 1 year postoperatively in 40 patients who underwent surgical elevation of the sternum by the modified method of Ravitch; D was _+0.030, S was 0.962_+0.030, F was , W was and C was 0.649_ In our cases 1 and 4, correction of the deformity was insufficient due to spontaneous extrusion of the traction screws, so the postoperative D and W values were low, but the indices of the other cases were comparable to the values reported by Hoshi. Consequently, this seems to be effective for the treatment of pectus excavatum. Case 7 The patient was a boy aged 4 years 7 months (Fig. 9). l~re+ollt, rllli+m Funnel Chest lndict~ l~qi+++tl++l mi+llh Imlt+, ++ ;++~+ +~ + "hl~'~l +.+lllj++ m+px (++=+l ] + Po+l+Ol+t+r+lli4 ill Figure 8--Funnel-chest indices (from Hoshi 1988) 3 are measured from a CT cross-section of the lowest portion of the sternum, d: sagittal diameter of the chest at the median depression; h and h' (h-->h'): sagittal diameters at the most prominent right and left anterior chest wall; w: transverse diameter of the chest; w': width of the depression. The was performed as described above. The first lasted for 3h 27min. During follow-up after discharge, one screw was found to have fallen out when he awoke on postoperative day 32. There was no sign of infection at the site of insertion. The other screw remained firmly in place and traction was continued using this screw. On postoperative day 78 the remaining traction screw was removed. He has been followed up for 3 years 2 months since the and the cosmetic results are excellent; there has been no recurrence of sternal depression. Case 8 A boy aged 5 years 5 months was treated using our technique (Fig. 10). External traction was continued for 71 days. His postoperative course has been followed up for 3 years 1 month. Case 3 A boy aged 15 years 4 months was treated using our technique (Fig. 11). His postoperative course was suddenly complicated by right-sided pneumothorax 7 days after surgery. Despite continuous chest drainage, there was no improvement. A bulla at the apex of the right lung was detected by CT scanning. He underwent endoscopic resection of the emphysematous bulla in the Department of Thoracic Surgery. After 5 years 2 months, his pectus excavatum shows correction. Table 2 Funnel-chest indices Case number Preoperative values D S F W C Postoperative values D S F W C mean +S.D _ _ _ _ _

6 122 British Journal of Plastic Surgery Pre-operatlon C P'~t-operat~ D~ptesshmlntlex Symmelrylndt,~ D~d/h S=h'/h ~ 1,018 LO00 -~ 0 ~ 7 I)cform~lwidthlndex Cht~l~hapel~dex W~r (~=d/w 0A89 ~-~ 0 0~ "~ Figure lo--case 8. (A) Preoperative views. (B) Views at 2 years 8 months postoperatively. (C) Comparison of funnel-chest indices preoperatively with those 2 years 8 months postoperatively. Figure 9--Case 7. (A) Preoperative view and CT findings. (B) Immediate postoperative view and CT findings 3 days postoperatively; CT shows the external traction using a TM Sternal Elevator. (C) View and CT findings 2 years 9 months postoperatively. Discussion In pectus excavatum, the indications for surgery are improvement of cardiopulmonary function and appearance. In many cases, however, the clinical findings are not consistent with the subjective symptoms. Surgical correction of the deformity is seldom required for improvement of cardiopulmonary function. However, an inferiority complex related to the deformity may affect the patient's social development. If psychological effects are taken into account, the deformity may require surgical treatment even in the absence of cardiopulmonary dysfunction. Since the first surgical procedure for pectus excavaturn was described, innumerable techniques have been reported. Two procedures, sternal elevation and turnover, are currently the most common. Sternal-elevation procedures, typically that of Ravitch, 4 are technically easy to perform but the original method has various disadvantages including the interruption of the blood supply to the sternum and postoperative stemal instability. To address these problems, the Ravitch method has undergone numerous modifications to preserve the internal mammary vessels and maintain sternal elevation using free bone grafts, vascularised rib grafts or wires and metal plates These modified methods are widely used. Sternal-turnover surgery was developed by Nissen 13 and Wada 14 to correct the depression by reconstruction of the thoracic cage after division of the chest wall. With this procedure, the blood supply to the sternum is interrupted, so infection and necrosis can occur secondary to ischaemia and recurrence of the depression may result from fibrosis. To address these problems, turning the sternum with a vascular pedicle and performing microsurgical vascular anastomosis of the internal mammary vessels have been reported./5'16 Thus, these two basic surgical procedures for pectus excavatum have undergone a variety of modifications based on long experience and are

7 Correction of pectus excavatum with sternal elevator 123 C Pre.opevation Post.og~:ration Depression Imlex D~--d / h 0.80"t -~ Symmetry Index S=h'/h ~ Flah~'ss Index F=h'l~ ' * Deformed width Index W=w' / w * 0 Chest shapejndex C=tl / '~' 0,495 "~ 0,637 Figure ll--case 3. (A) Preoperative views. (B) Views 5 years postoperatively. (C) Comparison of funnel-chest indices preoperatively with those 5 years postoperatively. still used today. However, both procedures are highly invasive, stimulating our search for a new technique. In 1998, Nuss et al reported a new minimally invasive technique for correction of pectus excavatum. ]7 Their procedure was based on the use of a metal plate to elevate the sternum. The costal cartilages are soft in infants and young children, and so the depressed sternum can be elevated, without surgical manipulation, by a 180 ~ rotation of a curved metal plate placed substernally. This technique is easy to perform and requires a very short operating time. However, the metal plate remains in the body and is associated with the risks of thoracotomy and damage to the epicardium. Also, the long-term outcome remains uncertain because the method of fixation of the metal plate and the timing of its removal are unclear. In early childhood, the costal cartilages are soft enough to enable the thoracic cage to be elevated to a new position simply by lifting the lower end of the sternum. This prompted us to develop our endoscopically assisted method for the surgical correction of pectus excavatum. We included minimal surgery to the sternum and costal cartilages in order to achieve elevation more easily, allow a stable new position to be achieved sooner and to prevent the recurrence of sternal depression. Elevation of the sternum using an external device is not a new method. It was performed widely in the 1920s but the previous technique was highly invasive and associated with a high risk of life-threatening infection. Is,t9 Consequently, it gradually fell into disuse. Elevation by internal fixation has long been the treatment of choice for this condition. Although an external device is used in our technique, elevation of the depressed sternum is based on continuous traction, as with bone lengthening. Consequently, our technique differs conceptually from the former method of external elevation. So far, we have used this new technique to treat 11 patients. Seven of these patients were less than 10 years old, and when these were compared with the four older patients, we observed that the took longer in the older group and better cosmetic results were achieved in the younger patients. For patients aged 10 years or younger, the took 3 h 21 min on average. The long operating time can be attributed to the use of endoscopic surgery through a single small incision. Conventional surgery under direct vision through a midline incision or a submammary-fold incision requires a far shorter operating time than our technique. However, increased experience with endoscopic procedures should shorten the operating time. 2 Also, our experience with these 11 patients indicates that the length of hospital stay and the duration of external traction can be shortened in the future. In infants and young children, because the extent of dissection of the thoracic cage is small and the manipulation of the depressed sternum and costal cartilages is limited, surgical invasion can be minimised. Our took 9 h 30 rain in a 28-year-old patient, possibly due to the wide extent of dissection required for correction, the extensive surgical manipulation of the costal cartilages and the concomitant use of the endoscope. The major disadvantage of this procedure is the restriction of daily activities due to the cumbersomeness of the traction device. Another disadvantage is that the is performed in two stages. In young children, adequate care must be taken to prevent falls when wearing the external traction device. None of the children in our series complained about the cumbersomeness of the external device and they behaved in the same manner as before the, indicating acceptance of the device. The traction device is freely removable, enabling the patient to shower with the traction screws inserted. No infection at the sites of screw insertion was seen in this series. Removal of the traction screws is comparable to procedures in which metal struts are used and the percutaneously inserted screws can be removed easily. In older patients, the screws can be removed as a day-case procedure under local anaesthesia. Although the number of cases is small and the postoperative follow-up is short, our procedure is potentially a new minimally invasive method for treating pectus excavatum. It is likely to be particularly useful in infants and young children, whose costal cartilages are soft. To evaluate this procedure further, we plan to perform the on more patients and continue with our postoperative follow-up assessment.

8 124 British Joumal of Plastic Surgery References 1. Onishi K, Sawaizumi M, Marnyama Y, Takagi S. Our techniques for maintaining the optical cavity in endoscopic plastic surgery. Jpn J Plast Reconstr Surg 1997; 40: Kobayashi S, u S, Komuro Y, Sakai Y, Ohmori K. Correction of pectus excavatum and pectus carinatum assisted by the endoscope. Hast Reconstr Surg 1997; 99: Hoshi E. Results of modified Ravitch procedure for sternal elevation of funnel chest: evaluated by funnel chest indices. J Jpn Soc Plast Reconstr Surg 1988; 8: Ravitch MM. The operative treatment of pectus excavatum. Ann Surg 1949; 129: Ravitch MM. Congenital Deformities of the Chest Wall and their Operative Correction. Philadelphia: WB Saunders, 1977; Dailey JE. Repair of funnel chest using sub-sternal osteoperiosteal rib graft strut: report of a case with four year follow-up. JAMA 1952; 150: Adams HD. Surgical treatment of pectus excavatum by costosternoplasty with rib strut. Surg Clin North Am 1960; 40: Jensen NK, Schmidt WR, Garamella J J, Lynch ME Pectus excavatum and carinatum: the how, when, and why of surgical correction. J Pediatr Surg 1970; 5: Gotzen L, Dragojevic D. Funnel chest correction by use of AO implants and instruments. Thorac Cardiovasc Surg 1979; 27: Hayashi A, Maruyama Y. Vascularized rib strut technique for repair of pectus excavatum. Ann Thorac Surg 1992; 53: Nakanishi Y, Nakajima T, Sakakibara A, Nishiyama T. A vascularised rib strut technique for funnel chest correction. Br J Plast Surg 1992; 45: Nakajima H, Chang H. A new method of reconstruction for pectus excavatum that preserves blood supply and costal cartilage. Plast Reconstr Surg 1999; 103: Nissen M. Osteoplastic procedure for correction of funnel chest. Am J Surg 1944; 64: Wada J. Surgical correction of the funnel chest 'steruotumover'. West J Surg Obstet Gynecol 1961; 69: Hirayama T, Nozaki M, Wakamatsu S. A new surgical method for repair of funnel chest. Ann Plast Surg 1985; 14: Ishikawa S, Uchinuma E, Itoh M, Shioya N. A simple stemal tumover procedure using a vascular pedicle for a funnel chest. Ann Plast Surg 1988; 20: Nuss D, Kelly RE Jr, Croitoru DE Katz ME. A 10-year review of a minimally invasive technique for the correction of pectus excavatum. J Pediatr Surg 1998; 33: Brown AL. Pectus excavatum (funnel chest): anatomic basis; surgical treatment of the incipient stage in infancy; and correction of the deformity in the fully developed stage. J Thorac Surg 1939; 9: Lester CW. Funnel chest and allied deformities of the thoracic cage. J Thorac Surg 1950; 19: The Authors Kiyoshi Onishi MD, Associate Professor Yu Maruyama MD, Professor and Chairman Department of Plastic and Reconstructive Surgery, Toho University Hospital, morinishi, Ota-ku, Tokyo , Japan. Correspondence to Dr Kiyoshi Onishi MD. Paper received 4 January Accepted 20 September Published online 5 January 2001.