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Complications of soft tissue expansion
BrifishJournalof PIastic Surgery (1988), 41,239-250 0 1988 The Trustees of British Association of Plastic Surgeons
Complications 0. ANTONYSHYN,
of soft tissue expans ‘ion and R. ZL IKER
J. S. GRUSS, S. E. MACKINNON
Divisions of Plastic Surgery, Sunnybrook Medical Centre and the Hospital for Sick Children, Toronto, Canada
Summary-This paper presents a critical review of the results of tissue expansion in our clinical experience. Seventy-six expansions performed in 66 patients between 1981 and August 1986 are included in the study. Complications necessitating some revision in the original treatment plan were documented in 39% of cases. However, sufficient tissue was usually generated to complete the proposed reconstruction without compromising the final results. The complications of tissue expansion are further analysed in relation to their anatomical distribution, time of onset and ultimate consequences. Causative factors are identified and preventative measures are introduced.
Tissue expansion has gained acceptance as a useful strategy in reconstructive surgery. Initially employed in post-mastectomy breast reconstruction, tissue expansion has more recently been adapted for increasingly diverse applications in multiple anatomical areas. However, the ultimate scope and limitations of this technique are as yet undefined. The purpose of this paper is to present a critical analysis of the results of tissue expansion in patients treated at the Hospital for Sick Children and the Sunnybrook Medical Centre in Toronto. The frequency and severity of complications in different anatomical sites, and their effect on the final reconstruction, are reviewed.
Clinical material Seventy-six expansions performed in 66 patients between 1981 and August 1986 are included in the study (Table 1). Thirty-one patients were male and 35 were female. The age of patients ranged from 4 to 89 years, with a mean of 34 years. Thirty-four
expansions were restricted to the head and neck region, while the remaining 42 cases comprised reconstruction in the upper and lower extremity, trunk and breast. Method of expansion A standardised technique for tissue expansion was employed to facilitate the interpretation of results in different clinical situations. A Radovan-type implant, consisting of an inflatable silastic envelope connected to a remote reservoir dome, was used in all instances. Preoperatively, the ultimate reconstruction was planned and local flaps were outlined. The tissues to be expanded included the entire surface area of the proposed flaps. Areas of scarring or previous irradiation were avoided whenever possible. The implant was inserted through an incision along one margin of the defect or along the periphery of the proposed flap. A pocket was then developed of sufficient size to accommodate the implant without excessive folding. The reservoir dome was always
Table 1 Patients with tissue expansion Tissue expanded
No. of patients
Male
Female
age
Mean
No. of expansions
Head &neck Breast Trunk Upper extremity Lower extremity
29 15 3 13 6
21 0 2 7 1
8 15 1 6 5
31 44 32 32 25
34 20 3 13 6
Total
66
31
35
34
76
239
240
placed in a remote subcutaneous pocket where it was easily palpable and readily accessible. To minimise the tension acting on the incision line during inflation, the expander was placed l2 cm from the incision. Deep sutures were used to approximate tissues of the roof and floor of the pocket around the implant to ensure that it remained well away from the incision. Suction drains were used in every case and maintained until drainage was minimal. Postoperatively, expansion was delayed until the incisions were completely healed (10-20 days). Serial inflations were then performed by percutaneous injection of saline into the reservoir dome. The frequency of inflation varied according to tissue tolerance, and the schedules of both the patient and the surgeon. Initial inflations were generally performed once a week, increasing to several times weekly towards the latter part of the expansion course. The amount of fluid injected was individualised for each patient, being dictated by palpable tenseness, blanching of the overlying skin and pain. Results Problems arising during the course of tissue expansion were critically reviewed. Complications were identified and analysed according to their anatomical distribution, time of onset, and detrimental effects upon the final reconstruction. Sequelae of tissue expansion Certain consequences of tissue expansion were found to be consistently and predictably associated with the expansion process. These conditions did not compromise the treatment plan or the final result and were therefore considered as sequelae of tissue expansion rather than complications. (a) Transient pain Pain associated with inflation of the implant was a common side-effect of tissue expansion. It was particularly severe with expansions of the distal extremities, dorsal trunk and forehead. Maximal discomfort typically coincided with a palpable tenseness in the expanded tissues at the termination of inflation. The discomfort was well localised and immediately relieved by the withdrawal of several millilitres of saline. There were no associated hyperaesthesiae or sensory deficits. Normally, such discomfort resolved completely over the ensuing
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6-12 hours and the patients remained pain-free during the intervals between expansions. (b) Anatomical variations in tissue extensibility The maximum rate and extent of soft tissue expansion varied considerably with the anatomical site. Whereas breast expansion proceeded rapidly with large volume increments of inflation, tissue expansion in the distal extremities was restricted. Small volumes of inflation caused significant tenseness and blanching in the overlying skin, and patient discomfort. Multiple implants were often required to generate sufficient tissue for reconstruction. Two major factors govern the efficiency with which tissue expansion can be performed in a given anatomical site. First is the inherent extensibility of overlying soft tissues. Second is the presence of a firm foundation for support of the implant. The tissue expander should ideally be placed on a base which resists mechanical deformation and directs the force of expansion outwards, towards the overlying soft tissues. This is particularly well illustrated in the lower extremity. Optimal tissue expansion per increment of inflation was obtained when implants were placed along the anterolateral or anteromedial aspect of the lower leg. The tibia provided a rigid buttress for the implant, promoting unidirectional expansion. On the other hand, implants placed in the posterior calf were less efficient, the force of expansion being distributed circumferentially to all yielding surfaces. (c) Capsuleformation All inert and non-degradable alloplastic materials implanted in human tissues become ensheathed by a discrete connective tissue capsule. This has been shown to be present as early as the third postoperative day (Vistnes et al., 1978). Following removal of the expander, a thick and non-pliable capsule occasionally maintained the spherical contour of the implant cavity, restricting the mobilisation and redraping of expanded flaps. Complications of tissue expansion In the present series, complications (as opposed to the sequelae noted above) were documented in 39% of cases. The actual frequency varied greatly with the anatomical site of expansion, being particularly high in the head and neck and lower extremity (Table 2). Problems associated with head and neck expansion alone accounted for 57% of the total
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COMPLICATIONS OF SOFT TISSUE EXPANSION
Table 2
Complications
of tissue expansion Anatomical site Head and neck
Complications
2 2
4
Total no. of expansions
34
20
number of recorded complications. All other areas, particularly the chest, trunk and dorsum of the hand, tolerated expansion extremely well. Complications of tissue expansion were further analysed to assess their deleterious effects upon the patient and the intended reconstruction. Those causing significant delays or complete failure in treatment were identified (Table 3). In 13 cases the final result was compromised and alternative means of reconstruction were required. Problems arising in the perioperative period, including intractable pain, haematoma and infection, generally necessitated premature removal of the tissue expander. Implant exposure during the early stages of inflation was observed in nine patients and was commonly Severity of complications No. of reconstructions
Total
1 1
17
Completed
2 3
1 1
9
1 1 2 1 1 6
13
17
2
2
1
Total no. of complications
Implant deflation Neuropraxia Pain Hematoma Infection - valve - implant Bone resorption Striae Valve exposure Implant exposure
1 1
Lower extremit)
1
1
Compromised
Upper extremity
1
1 4 2 5
Complications
Trunk
1
Implant deflation Neuropraxia Pain Hematoma Infection -valve -implant Bone resorption Striae Valve exposure Implant exposure -incisional dehiscence -inadequate tissue -implant buckling
Table 3
Breast
1
2
0
4
5
3
13
6
associated with incisional dehiscence. In all cases, the implant pocket was secondarily infected within a short period of time, precluding further expansion. Despite the reported frequency of complications, it is important to note that the course of tissue expansion was completed and an excellent result obtained in 83% of our cases. The majority of complications documented in the present study did not affect the proposed reconstruction adversely. Most occurred in the final stages of expansion, at near maximal volumes of inflation. These included implant deflation, neuropraxia, bone resorption and late implant exposure. In all cases, sufficient tissue was generated to complete the reconstruction as planned. (a) Implant failure Mechanical failures resulting in implant deflation or valve leakage are exceedingly rare. Exacerbating factors such as trauma, inadvertent implant puncture, or stress fractures occurring in folds of the silastic membrane must be ruled out. Two cases of spontaneous deflation were observed late in the course of expansion, with no detrimental effect on the final reconstruction. In both cases the leak was identified at the junction of the tissue expander and the silastic connecting tube. (b) Compromise of vital structures Thirteen tissue expansions were performed in the cheek and neck. There were no reported cases of
242
airway obstruction or dysphagia. Similarly, six patients underwent eyelid expansion. Ocular discomfort or visual disturbance was not encountered. Modified implant design, using a rigid back wall and expansile anterior portion, was instrumental in regulating the direction of expansion and minimising these potential problems. (c) Neuropraxiu Several factors may predispose to the onset of neuropraxia in association with tissue expansion. Traction may be exerted on a peripheral nerve where a particularly unyielding anatomical arrangement restricts its mobility over a progressively enlarging prosthesis. Alternatively, excessively large volumes or rapid rates of inflation may apply sufficient direct mechanical force to cause nerve compression. When recognised and treated early, before the onset of focal demyelination, the consequences of neuropraxia can be expected to resolve quickly. Despite the large number of expansions performed directly over the path of major nerves, particularly in the cheek and extremities, clinical signs of nerve compression are rare. In the present series of 76 expansions, only three cases of neuropraxia were documented. In two cases, temporary numbness of the sural nerve distribution followed expansion of the posterior calf. In the third, transient numbness was noted in the distribution of the radial sensory nerve following expansion of the dorsum of the hand. This quickly resolved with slight deflation of the implant. Case I. A 37-year-old woman presented with a hyperaesthetic, depressed scar of the left medial calf. Seven years previously she had undergone excision of a malignant melanoma with a 5 cm resection margin. The resulting defect was skin grafted. The patient complained of persistent hypersensitivity of the skin graft which was refractory to treatment with anaesthetic nerve blocks. Through an incision at the posterior margin of the defect, a large subfascial pocket was dissected over the posterolateral calf. A 250 cc tissue expander was placed in the cavity, deep to the course of the sural nerve. Subsequent inflations proceeded uneventfully to a volume of 190 cc before the patient first reported the onset of paraesthesiae over the dorsolateral aspect of the foot. The area of anaesthesia was mapped out. An increase in the vibratory sensory threshold was documented using both a 256 cps tuning fork and an amplitude variable fixed frequency (120 cps) vibrometer. The threshold for two-point discrimination was elevated to 70 mm, compared to 27 mm on the corresponding surface of the contralateral foot.
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Expansion was discontinued and the implant removed. An expanded fasciocutaneous flap was elevated and transposed to resurface the defect. Postoperatively, the paraesthesiae resolved and objective sensory testing confirmed the return of normal sensation.
(d) Intractablepain Intractable pain is an uncommon consequence of tissue expansion. One patient complained of severe, persistent discomfort localised to the soft tissues overlying a forehead expander. There were no associated objective findings of sensory deficits. Pain was first noted in the early postoperative period and the patient was unable to tolerate minimal volumes of inflation. Failure to control the pain following temporary deflation demanded removal of the implant. (e) Haematoma
Haematoma is minimised by meticulous haemostasis and the use of suction drains. When clinical examination reveals the presence of a significant haematoma, immediate surgical drainage and irrigation of the implant cavity are indicated. Secondary consequences such as infection, excessive tension on expanded tissues and capsule formation can be prevented by prompt and adequate treatment. In the present series, a significant haematoma was noted in the early postoperative period in one patient. Case 2. A 25-year-old male sustained a devastating degloving injury to the right hand in March 1985, with amputations of the index finger and distal third of the thumb. A large cutaneous defect of the thenar eminence and dorsal surface of the hand was initially covered with split thickness skin grafts. In August 1985 the patient presented with an adherent, hyperaesthetic skin graft on the dorsum of the hand and a contracture of the first web-space. He was taken to the operating room where a 250 cc tissue expander was inserted into a pocket.on the extensor surface of the distal forearm. The expanded tissues were to provide sensate, durable cover to resurface the first web-space. On the first postoperative day, congestion and poor capillary refill were noted in the skin overlying the implant. The patient was immediately_returned to the operating room where the incision was opened and a large haematoma evacuated. Following thorough haemostasis and irrigation of the pocket, the tissue expander was reinserted. However, continued concern about viability of the overlying skin necessitated removal of the implant and further attempts at tissue expansion were abandoned.
COMPLICATIONS
243
OF SOFT TISSUE EXPANSION
The frequency of percutaneous injections predisposes to infection at the site of the reservoir dome. However, its placement in a separate pocket remote from the tissue expander results in a localised infection which does not necessarily compromise further expansion. Cellulitis was noted over the reservoir dome in one patient. Following treatment with intravenous antibiotics, local signs of inflammation resolved promptly and serial inflations were resumed. Infection of the implant cavity is a more serious complication. Of the three cases documented in our series, only one resolved following treatment with intravenous antibiotics. The remaining two patients required surgical drainage of the subcutaneous pocket and removal of the implant. The soft tissues remained indurated for a prolonged period of time and further attempts at expansion were not made. (g) Bone resorption Forehead expansion in two adult patients resulted in significant resorption of calvarial bone directly beneath the implant. There was no evidence of similar resorption in the remaining six forehead expansions or in six scalp expansions. The same treatment protocol was followed in all cases, and specific exacerbating or causative factors could not
be identified in the two affected patients. The tissue expanders were all placed in a subgaleal pocket, leaving pericranium intact over the surface of the skull. Subsequent inflation to a volume of 300400 cc proceeded uneventfully over a period of 3 months. The calvarial resorption was first noticed upon removal of the implant. An obvious depression in the frontal bone conformed to the exact dimensions and shape of the implant. The resulting frontal contour exaggerated the prominence of the supraorbital ridge, producing a conspicuous skeletal deformity. Case 3. A %-year-old male previously sustained a selfinflicted gunshot wound to the face. Initial treatment consistedof anatomic reduction and rigid internal fixation of all fracture fragments, and primary bone grafting to bony deficiencies of the mandible and maxilla. In October 1984 the patient was admitted for a staged nasal reconstruction. In the first operation, a 250 cc Radovan tissue expander was introduced through a coronal incision into a subgaleal pocket in the forehead. Over the ensuing 3 months, the implant was inflated to a volume of 355 cc. In January 1985 an oblique expanded forehead flap was elevated and draped over a cantilever rib graft to reconstruct the nose. Removal of the expander revealed a shallow, crater-like depression in the frontal bone (Fig. 1). Flattening of the normal forehead convexity amplified the fullness of the glabella and superciliary regions. The bony rim of the cavity was resected to provide a normal forehead contour.
Fig. 1 Figure l-Case 3. Forehead expansion was completed in this 55-year-old patient. (A) Following removal of the expander, a craterlike depression is noted in the frontal bone. The extent of bone resorption is better demonstrated after elevation of the periosteum over the supraorbital region. (B) The depression conforms to the dimensions and shape of the implant, flattening the normal convexity of the forehead.
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Fig. 2 Figure 2-Case 4. A 16-year-oldfemale with Poland’s syndrome. (A) The left breast was extremely hypoplastic and the sternal head of the pectoralis major muscle was absent. (B) Multiple red striae, noted following expansion to a total volume of 790 cc.
(h) Striae Striae are bands of thinned, red, wrinkled skin, which result from atrophy and rupture of collagenous fibres in the dermis. They are therefore frequently observed in the skin of the pregnant abdomen and might reasonably be expected to be a common sequela of tissue expansion. In actual fact, however, striae formation was documented in only one of 76 tissue expansions performed in the present series. A standard rate and volume of inflation were employed in this patient, and no other exacerbating factors could be identified.
sion (Fig. 3). The inflation reservoir had initially been placed in a subcutaneous pocket in the posterior neck, remote from the expander itself. The rigidity of the silastic dome, thinness of subcutaneous tissues, and shearing forces generated by repetitive neck motion and contractions of the adjacent sternomastoid muscle, may all have been contributing factors resulting in valve exposure. Direct excision and primary closure of the area of skin necrosis following a repositioning of the valve allowed further expansion to proceed without incident.
Case 4. A 16-year-old girl presented with a congenital deformity of the left breast (Fig. 2). Clinical examination revealed the stigmata of Poland’s sydrome. Syndactyly involving the fingers of the left hand was noted. The left breast was extremely hypoplastic and the sternal head of the pectoralis major muscle was absent. A functioning clavicular head of the pectoralis muscle was identified. The projected location of the submammary fold was mapped out on the patient’s left anterior chest. Through a transverse incision at this level, a 700 cc round tissue expander was inserted into a large subcutaneous pocket. Subsequent inflations proceeded at a rate of 100 cc weekly to a total volume of 790 cc. Striae formation was first noted in the last few weeks of expansion. The tissue expander was subsequently removed and the reconstruction completed using a custom-made prosthesis with a moulded attachment to fill out the missing portion of the pectoralis muscle. The striae have persisted.
(i) Value exposure
Skin erosion over the reservoir dome was observed in one patient undergoing cheek and neck expan-
Fig. 3
Figure 3-The reservoir dome in this patient was placed in a subcutaneous pocket in the posterior triangle of the neck. Progressive erosion of overlying soft tissues resulted in exposure.
245
COMPLICATIONS OF SOFT TISSUE EXPANSION
(j) Implant exposure
Exposure of the silastic implant was the most frequently observed complication of tissue expansion, occurring in 20% of all cases. Three major causative factors were identified. These included dehiscence of the incision, erosion through inadequate tissue cover or pressure necrosis of soft tissues over a persistent fold in the silastic envelope. In an effort to prevent early dehiscence of the incision, several measures were employed routinely. These included the placement of incisions at the periphery of the implant pocket using a staggered, two-layer closure, and delaying implant inflation until sufficient time had passed for the wound to heal. Nonetheless, incisional dehiscence was the most common cause of implant exposure and generally occurred early in the course of expansion. The consequences were therefore serious
and the final reconstruction was compromised significantly delayed in most cases.
or
Case 5. A 31-year-old man had previously sustained a traumatic avulsion of the right great toe. Primary treatment included a revision of the amputation at the proximal phalangeal level and skin grafting of the cutaneous defect on the dorsal aspect of the foot (Fig. 4). The patient subsequently developed an extremely painful amputation stump with an adherent, hyperaesthetic skin graft. Through an incision between the first and second metatarsal along the margin of the skin graft, a large subfascial pocket was dissected on the dorsolateral surface of the foot. Particular care was taken to avoid any undermining of the graft. A 100cc tissue expander was placed in the pocket and the incision closed in two layers. In the third postoperative week, serial inflations were started at a rate of 10 cc weekly. Dehiscence of the
Fig. 4 Figure 4-Case 5. A 31-year-old male with a hyperaesthetic skin graft on the dorsum of the right foot. (A) An incision was inappropriately made along the margin of the previous scar, as indicated by the dotted line. The expander was placed in a subfascial pocket on the dorsolateral surface of the foot. (B) Dehiscence of the incision and exposure of the implant occurred in the fifth postoperative week.
246 incision occurred in the fifth week, at a total volume of only 35 cc. The patient was immediately admitted for a course of rapid expansion under close supervision. However, the early onset of secondary infection in the implant cavity prompted immediate removal of the tissue expander. The amputation was eventually revised at the base of the first metatarsal, permitting excision of the graft and scar tissue, and direct closure of the defect. Previously scarred or irradiated soft tissues tolerate expansion poorly and should be avoided whenever possible. Both tissue extensibility and blood supply are limited, causing a palpable tenseness and blanching in the skin with minimal increments of inflation. Thinning and necrosis of skin with subsequent implant exposure were observed in two patients. In both cases exposure occurred late in the course of expansion at near
maximal volumes of inflation, Sufficient tissue was available to complete the planned reconstruction with expanded flaps. A third, and very common, cause of implant exposure is related to a fundamental deficiency in the design of tissue expanders. The envelope consists of a redundant surface area of silastic membrane with limited inherent extensibility. Rather than expanding, the implant functions as an empty folded bag which gradually unfurls as it fills. Irregularities in the surface contour persist until near maximal volumes of inflation. Clinically, prominent folds in the silastic envelope cause focal pressure necrosis and progressive erosion in the overlying soft tissues. Measures to eradicate these folds, such as manipulation of the implant, rapid inflation or deflation, proved ineffective. The frequency of soft tissue erosion and implant exposure varied with the anatomical site of expansion. The thickness of the skin and subcutaneous tissues in the trunk and extremities offered some protection. More importantly, the inclusion of an additional vascularised layer of fascia or muscle between the implant and cutaneous surface resulted in the overlying skin being less susceptible to pressure necrosis. Even under such favourable circumstances, however, skin erosion and implant exposure were observed in one patient undergoing breast expansion. Case 6. A 43-year-old woman presented with a right postmastectomy deformity. Two years previously the patient had undergone a modified radical mastectomy for breast carcinoma, followed by 6 months of chemotherapy. Clinical examination revealed a single oblique scar over the right chest, soft, pliable skin and a functioning pectoralis major muscle. She was considered a good candidate for breast expansion and reconstruction.
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Through an incision in the previous scar, a 700 cc round tissue expander was introduced into a submuscular pocket. Subsequent expansion proceeded uneventfully to a volume of 615 cc when a prominent buckle was first noted in the medial aspect of the implant, superior to the mastectomy scar. Over the ensuing week, the overlying skin became erythematous and mildly tender. Failure of this condition to resolve following treatment with intravenous antibiotics suggested the presence of fat necrosis. Progressive thinning of the soft tissues eventually culminated in complete erosion and exposure of the implant (Fig. 5). An attempt was made to salvage the tissue expander in this patient. She was immediately taken to the operating room where the implant was partially deflated. The capsule surrounding the exposure site was found to be friable and necrotic, requiring extensive debridement. The ulcer itself was excised in elliptical fashion and closed directly. However, the wound continued to break down and the implant was removed 3 days later. The cheek and neck were particularly susceptible to focal pressure necrosis and implant exposure. Contributing factors included the thinness of overlying skin and subcutaneous tissues and constant shearing forces generated by repetitive neck and jaw motion. More importantly, gravitational pooling of injected saline in the most dependent portion of the implant predisposed of differential expansion and inferior migration of the entire tissue expander. Buckling of the implant occurred where further migration was obstructed, as in the inferior margin of the mandible and over the clavicle. Exposure in these anatomically predictable sites was noted in five cases.
Fig. 5 Figure S-Case 6. Despite submuscular placement of the implant in this patient undergoing breast expansion, a persistent fold in the silastic envelope resulted in focal pressure necrosis and eventual exposure.
241
COMP‘Ll:CATIONS OF SOFT TISSUE EXPANSION
Fig. 6 Figure &Case 7. A 55-year-old woman with a post-traumatic scar. (A) The defect measured 25 x 10 cm and involved the ieft cheek, chin and lower eyelid. (B) Through a rhytidectomy incision, a large subcutaneous pocket was dissected, as indicated by the dotted line. The intended location of the implant is demonstrated. (C) The problems associated with cheek and neck expansion are well illustrated here. Gravitational pooling of saline resulted in disproportionate expansion and thinning of skin at the lower pole of the implant. The entire expander migrated inferiorly and buckled over the clavicle, causing erosion with necrosis of overlying soft tissues. (D) The result, 3 months postoperatively.
248 Case 7. A %-year-old woman was referred for treatment of a post-traumatic plaque-like scar of the left cheek, measuring 25 x 10 cm (Fig. 6). The defect consisted of thick, non-pliable cicatrix which was associated with an ectropion of the left lower eyelid. Through a rhytidectomy incision, skin flaps were elevated in a plane immediately superficial to the SMAS. A large subcutaneous pocket was developed, extending well into the neck but avoiding all areas of scarring. A rectangular tissue expander was inserted and the reservoir dome was placed in a remote subcutaneous pocket over the sternomastoid muscle. In the first postoperative week, erythema and thinning of skin were noted over the reservoir dome. The valve became exposed shortly thereafter. All necrotic and atrophic skin was promptly excised and the defect closed primarily. The valve was repositioned over the mastoid process and serial inflations were resumed. Injected fluid pooled in the dependent portion of the implant, causing differential expansion and thinning of the overlying tissues. The entire expander migrated inferiorly as far as the clavicle where a persistent fold developed in the silastic envelope. Overlying tissues eventually eroded, exposing the implant and precluding further expansion. The patient was taken to the operating room where necrotic skin was excised and the implant removed. Remaining expanded tissue was incorporated in a medially-based cheek/neck rotation flap. The dimensions of the flap were sufficient to permit excision and resurfacing of most of the scar, leaving an 8 x 3 cm residual defect.
Discussion The concept of soft tissue expansion by gradual inflation of a prosthesis was initially adapted for clinical use in breast reconstruction (Radovan, 1978). It offered the potential to generate a required amount of soft tissue while permitting some control of the eventual size and shape of the reconstructed breast mound. The technique was simple and excellent results could be anticipated. In particular, reviews of clinical series demonstrated minimal complication rates ranging from 0 (Argenta et al., 1983a) to 14% (Radovan, 1982). Tissue expansion became firmly established as a reconstructive option for the post-mastectomy patient. More recently, extensions of these same principles and refinements in technique prompted the adaptation of tissue expansion for an increasing variety of indications in multiple anatomical sites, including the face (Argenta et al., 1983b), scalp (Manders et al., 1984a; Leonard and Small, 1986), and extremities (Sasaki, 1984; Mackinnon and Gruss, 1985; Mackinnon and Dellon, 1987). The increase in scope of applications has also been
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associated with an increased incidence of complications. In anatomical regions excluding the breast, Argenta et al. (1985) documented complications in 24% of their first 30 cases. Similarly, a review of 41 expansions performed for a wide spectrum of problems revealed an overall complication rate of 40% (Manders et al., 1984b). The results of tissue expansion vary greatly with the anatomical site. Regional differences in skin laxity, vascular supply, thickness of subcutaneous tissues and the presence or absence of an additional layer of muscle or fascia contribute to the variability. The present clinical series comprises 76 expansions, 53 of which were performed in the head and neck or the extremities. The incidence of complications was particularly high in these two areas, occurring in 50% and 47% of cases respectively. The remaining expansions were restricted to the chest and trunk and were distinguished by consistently good results and minimal complications. The severity of complications and their impact on the final outcome of treatment are more difficult to evaluate: 38% of patients undergoing tissue expansion sustained some form of complication requiring a revision in the original treatment plan. These revisions included the implementation of ancillary medical or operative procedures, temporary reductions in the rate or quantity of serial inflations, and premature discontinuation of expansion. However, the consequences rarely involved loss of tissue and the intended reconstructions were completed successfully in 83% of cases. It is particularly important to consider the quality of reconstruction that is now available as a result of tissue expansion. Unlike other reconstructive techniques, expansion provides a surplus of locally available tissue with the required colour, texture and hair-bearing characteristics. Sufficient tissue is generated to resurface both donor and recipient sites simultaneously, thus minimising the donor site deformity. The final result is frequently far superior to that obtained by alternative means of reconstruction. In the future, efforts to decrease the overall complication rate must be directed at the anticipation of certain problems and their prevention. Emphasis on implant modifications and refinements in surgical technique designed to minimise the risk of exposure would influence the results of tissue expansion most dramatically. Early incisional dehiscence can be averted by the employment of radial or marginal incisions which are placed well away from the site of expansion. A staggered
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COMPLICATIONS OF SOFT TISSUE EXPANSION
double-layer closure restricts migration of the implant under the incision, and sufficient time must be allowed for the incision to heal prior to commencement of serial inflations. Erosion and pressure necrosis of soft tissues over the implant are more difficult to control. Although previous scarring and atrophy in expanded tissue were causative factors in two cases, the majority of implant exposures occurred in uninjured and well vascularised skin. Certain anatomical sites, such as the cheek and neck, were particularly susceptible. The relative thinness of skin and subcutaneous tissues in this area, and gravitational pooling of saline resulting in differential expansion and implant migration may all have contributed. Most importantly, the formation of persistent buckles in the implant is an ominous sign which is frequently resistant to external manipulation. Buckling of the silastic membrane is an inherent property of all tissue expanders currently available. Modifications in implant design incorporating an expansile, distensible membrane would most significantly alter the frequency of observed complications.
References Argenta, L. C., Marks, M. W. and Grabb, W. C. (1983a). Selective use of serial expansion in breast reconstruction. Annals ofPlastic Surgery, 11, 188. Argenta, L. C., Watanabe, M. J. and Giiabb, W. C. (1983b). The use of tissue expansion in head and neck reconstruction. Annals of Plastic Surgery, 11, 3 1. Argenta, L. C., Marks, M. W. and Pasyk, K. A. (1985). Advances in tissue expansion. Clinics in Plastic Surgery, 12, 159. Leonard. A. G. and Small. J. 0. (1986). Tissue exuansion in the treatment of alopecia. ‘British‘Jourkl of Plastic Surgery, 39, 42.
Macklon, S. E. and Dellon, A. L. (1987). Soft tissue expansion in hand reconstruction. British Journal of Hand Surgery, 12B, 73.
Macklnnon, S. E. and Gruss, J. S. (1985). Soft tissue expanders in upper limb surgery. Journal of Hand Surgery, IOA, 749. Maaders, E. K., Graham III, W. P., Schenden, M. J. aad Davis, T. S. (1984a). Skin expansion to eliminate large - scalp_ defects. Annals of Plastic Surgery, 12, 305. Manders. E. K.. Schonden. M. J.. Furrev. J. A.. Hetzler. P. T.. Davis,‘T. S.’ and Graham Iii, W. fi: (198hb). Soft tissu; expansion : concepts and complications. Plastic and Reconstructive Surgery, 14,493. Radovan, C. (1978). Reconstruction of the breast after radical mastectomy using a temporary expander. Plastic Surgery Forum. 1,41.
Radovan, C. (1982). Breast reconstruction after mastectomy using the temporary expander. Plastic and Reconstructive Surgery, 69, 195. Sasakl, G. H. (1984). Extremity soft tissue reconstruction. In Habal, M. (Ed.) Advancesin PlasticandReconstructive Surgery,
Vol 1. Chicago: Year Book Medical Publishers.
Vistnes, L. M., Ksander, G. A. and Kosek, J. (1978). Study of
encapsulation of silicone rubber implants in animals. A foreign body reaction. Plastic and Reconstncctive Surgery, 62, 580.
The Authors 0. Aatooyshyn, MD, FRCS(C), Clinical fellow, Division of Plastic Surgery, Sunnybrook Medical Centre, Toronto. J. S. Gruss, MB, FRCS(C), Consultant and Head, Division of Plastic Surgery, Sunnybrook Medical Centre, Toronto. S. E. Macklnnon, MD, FRCS(C), Consultant, Division of Plastic Surgery, Sunnybrook Medical Centre, Toronto. R. Zuker, MD, FRCS(C), Consultant and Head, Division of Plastic Surgery, Hospital for Sick Children, Toronto. Requests for reprints to: Dr J. S. GNSS, Division of Plastic Surgery, Sunnybrook Medical Centre, 2075 Bayview Avenue, HG 948, Toronto, Ontario M4N 3M5, Canada. Paper received 7 April 1987. Accepted 7 July 1987.
Discussion by Mr Oliver Fenton, FRCS There can be few areas of surgery where an unchanged complication rate of 40% over a 10 year period has been accompanied by an increasing acceptance of the procedure by clinicians. The two main reasons for this are the quality of reconstruction that can be achieved using tissue expanders and the artificial nature of this complication rate. Very few complications will prevent satisfactory completion of a reconstruction and in most cases problems such as exposure and infection can be controlled until expansion is complete. Surgical experience should have reduced the complication rate but this has been offset by the widening application of tissue expanders, as highlighted in this paper. This has been compounded by a failure to alter both the basic shape of the original implant and the surgical approach. This paper goes some way towards analysing problems in implant design and use, but it also perpetuates several misconceptions. Chief amongst these are base plates, directional expansion, radial incisions, delaying inflation until the wound has “healed”, and placing the expander outside the area to be excised. Radovan’s original implants were thick-walled, rectangular, folded and incorporated a base plate, and in my view are the antithesis of an implant designed for skin expansion. The base plate is supposed to give direction to the expansion and this idea of “directional” expansion has been further developed by several manufacturers. This ignores Newton’s Third Law of action and reaction-direction is provided by the base on which the
250 entire implant sits and cannot be achieved by an integral rigid plate. Such an implant will expand almost as well if turned upside down, except for the constraints on lateral expansion imposed by the base plate. Base plates serve no useful function and are a significant cause of complications, especially on curved surfaces such as the head and neck and limbs, and prevent the expander from recruiting the maximum amount of skin by limiting lateral expansion. Any “direction” that occurs is at the expense of this recruitment and will result in thinning of the overlying skin, as best displayed in implant exposure due to “knuckling”. The authors suggest that incisions radial to the expander reduce the likelihood of wound exposure. Expansion occurs in all directions over an implant and if a wound is caught up in the expansion process it is liable to dehiscence whatever its direction. This is more likely when the incision is placed next to an immobile area such as the ear or a scar, as the pull on the wound cannot be dispersed. The only sure way to prevent wound dehiscence is to make sure the wound is well away from the site for expansion. However, my main disagreement with Dr Antonyshyn’s paper concerns the timing of expansion. Delaying expansion by a few weeks does not allow wound “healing” to occur to any useful degree. It does, however, allow the development of a capsule around the implant, so that much of the force of expansion is wasted against the capsule rather than the skin. I believe that this can cause considerable discomfort to the patient and certainly
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prolongs the time taken for full expansion. My own practice is to inflate to the limits of safety on the operating table and then continue expansion on a daily basis when logistically possible. As the authors point out, almost all current implants rely on an unfolding of the silicone envelope to produce expansion, with resultant knuckling and frequent exposure. The better quality implants are capable of expansion to 6 times their stated volume and since 1985 I have been requesting two manufacturers to capitalise on this fact and produce flat, pliable implants. However, when flat expanders did appear, from another company, they incorporated a firm rim that cut into the base of the expanded skin with predictable results. I agree with the authors that modifications to current designs are long overdue, and we have designed a soft, flat, croissantshaped expander that we have used for the past 3 months with great success, to the extent that we will cease to use conventional expanders once our stocks run out. These can be inserted through a small remote incision and then positioned using a “flotation-displacement” principle. The croissant shape embraces the area to be excised and dispenses with the need for additional skin incisions to make optimum use of the expanded skin. Much the same effect can be achieved by placing part of the expander under the defect, disregarding the expansion of the defect itself. Tissue expansion will not realise its full potential until the complication rate is consistently below 10%. I believe we will achieve this in the next 2-3 years.
Complications 0. ANTONYSHYN,
of soft tissue expans ‘ion and R. ZL IKER
J. S. GRUSS, S. E. MACKINNON
Divisions of Plastic Surgery, Sunnybrook Medical Centre and the Hospital for Sick Children, Toronto, Canada
Summary-This paper presents a critical review of the results of tissue expansion in our clinical experience. Seventy-six expansions performed in 66 patients between 1981 and August 1986 are included in the study. Complications necessitating some revision in the original treatment plan were documented in 39% of cases. However, sufficient tissue was usually generated to complete the proposed reconstruction without compromising the final results. The complications of tissue expansion are further analysed in relation to their anatomical distribution, time of onset and ultimate consequences. Causative factors are identified and preventative measures are introduced.
Tissue expansion has gained acceptance as a useful strategy in reconstructive surgery. Initially employed in post-mastectomy breast reconstruction, tissue expansion has more recently been adapted for increasingly diverse applications in multiple anatomical areas. However, the ultimate scope and limitations of this technique are as yet undefined. The purpose of this paper is to present a critical analysis of the results of tissue expansion in patients treated at the Hospital for Sick Children and the Sunnybrook Medical Centre in Toronto. The frequency and severity of complications in different anatomical sites, and their effect on the final reconstruction, are reviewed.
Clinical material Seventy-six expansions performed in 66 patients between 1981 and August 1986 are included in the study (Table 1). Thirty-one patients were male and 35 were female. The age of patients ranged from 4 to 89 years, with a mean of 34 years. Thirty-four
expansions were restricted to the head and neck region, while the remaining 42 cases comprised reconstruction in the upper and lower extremity, trunk and breast. Method of expansion A standardised technique for tissue expansion was employed to facilitate the interpretation of results in different clinical situations. A Radovan-type implant, consisting of an inflatable silastic envelope connected to a remote reservoir dome, was used in all instances. Preoperatively, the ultimate reconstruction was planned and local flaps were outlined. The tissues to be expanded included the entire surface area of the proposed flaps. Areas of scarring or previous irradiation were avoided whenever possible. The implant was inserted through an incision along one margin of the defect or along the periphery of the proposed flap. A pocket was then developed of sufficient size to accommodate the implant without excessive folding. The reservoir dome was always
Table 1 Patients with tissue expansion Tissue expanded
No. of patients
Male
Female
age
Mean
No. of expansions
Head &neck Breast Trunk Upper extremity Lower extremity
29 15 3 13 6
21 0 2 7 1
8 15 1 6 5
31 44 32 32 25
34 20 3 13 6
Total
66
31
35
34
76
239
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placed in a remote subcutaneous pocket where it was easily palpable and readily accessible. To minimise the tension acting on the incision line during inflation, the expander was placed l2 cm from the incision. Deep sutures were used to approximate tissues of the roof and floor of the pocket around the implant to ensure that it remained well away from the incision. Suction drains were used in every case and maintained until drainage was minimal. Postoperatively, expansion was delayed until the incisions were completely healed (10-20 days). Serial inflations were then performed by percutaneous injection of saline into the reservoir dome. The frequency of inflation varied according to tissue tolerance, and the schedules of both the patient and the surgeon. Initial inflations were generally performed once a week, increasing to several times weekly towards the latter part of the expansion course. The amount of fluid injected was individualised for each patient, being dictated by palpable tenseness, blanching of the overlying skin and pain. Results Problems arising during the course of tissue expansion were critically reviewed. Complications were identified and analysed according to their anatomical distribution, time of onset, and detrimental effects upon the final reconstruction. Sequelae of tissue expansion Certain consequences of tissue expansion were found to be consistently and predictably associated with the expansion process. These conditions did not compromise the treatment plan or the final result and were therefore considered as sequelae of tissue expansion rather than complications. (a) Transient pain Pain associated with inflation of the implant was a common side-effect of tissue expansion. It was particularly severe with expansions of the distal extremities, dorsal trunk and forehead. Maximal discomfort typically coincided with a palpable tenseness in the expanded tissues at the termination of inflation. The discomfort was well localised and immediately relieved by the withdrawal of several millilitres of saline. There were no associated hyperaesthesiae or sensory deficits. Normally, such discomfort resolved completely over the ensuing
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6-12 hours and the patients remained pain-free during the intervals between expansions. (b) Anatomical variations in tissue extensibility The maximum rate and extent of soft tissue expansion varied considerably with the anatomical site. Whereas breast expansion proceeded rapidly with large volume increments of inflation, tissue expansion in the distal extremities was restricted. Small volumes of inflation caused significant tenseness and blanching in the overlying skin, and patient discomfort. Multiple implants were often required to generate sufficient tissue for reconstruction. Two major factors govern the efficiency with which tissue expansion can be performed in a given anatomical site. First is the inherent extensibility of overlying soft tissues. Second is the presence of a firm foundation for support of the implant. The tissue expander should ideally be placed on a base which resists mechanical deformation and directs the force of expansion outwards, towards the overlying soft tissues. This is particularly well illustrated in the lower extremity. Optimal tissue expansion per increment of inflation was obtained when implants were placed along the anterolateral or anteromedial aspect of the lower leg. The tibia provided a rigid buttress for the implant, promoting unidirectional expansion. On the other hand, implants placed in the posterior calf were less efficient, the force of expansion being distributed circumferentially to all yielding surfaces. (c) Capsuleformation All inert and non-degradable alloplastic materials implanted in human tissues become ensheathed by a discrete connective tissue capsule. This has been shown to be present as early as the third postoperative day (Vistnes et al., 1978). Following removal of the expander, a thick and non-pliable capsule occasionally maintained the spherical contour of the implant cavity, restricting the mobilisation and redraping of expanded flaps. Complications of tissue expansion In the present series, complications (as opposed to the sequelae noted above) were documented in 39% of cases. The actual frequency varied greatly with the anatomical site of expansion, being particularly high in the head and neck and lower extremity (Table 2). Problems associated with head and neck expansion alone accounted for 57% of the total
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COMPLICATIONS OF SOFT TISSUE EXPANSION
Table 2
Complications
of tissue expansion Anatomical site Head and neck
Complications
2 2
4
Total no. of expansions
34
20
number of recorded complications. All other areas, particularly the chest, trunk and dorsum of the hand, tolerated expansion extremely well. Complications of tissue expansion were further analysed to assess their deleterious effects upon the patient and the intended reconstruction. Those causing significant delays or complete failure in treatment were identified (Table 3). In 13 cases the final result was compromised and alternative means of reconstruction were required. Problems arising in the perioperative period, including intractable pain, haematoma and infection, generally necessitated premature removal of the tissue expander. Implant exposure during the early stages of inflation was observed in nine patients and was commonly Severity of complications No. of reconstructions
Total
1 1
17
Completed
2 3
1 1
9
1 1 2 1 1 6
13
17
2
2
1
Total no. of complications
Implant deflation Neuropraxia Pain Hematoma Infection - valve - implant Bone resorption Striae Valve exposure Implant exposure
1 1
Lower extremit)
1
1
Compromised
Upper extremity
1
1 4 2 5
Complications
Trunk
1
Implant deflation Neuropraxia Pain Hematoma Infection -valve -implant Bone resorption Striae Valve exposure Implant exposure -incisional dehiscence -inadequate tissue -implant buckling
Table 3
Breast
1
2
0
4
5
3
13
6
associated with incisional dehiscence. In all cases, the implant pocket was secondarily infected within a short period of time, precluding further expansion. Despite the reported frequency of complications, it is important to note that the course of tissue expansion was completed and an excellent result obtained in 83% of our cases. The majority of complications documented in the present study did not affect the proposed reconstruction adversely. Most occurred in the final stages of expansion, at near maximal volumes of inflation. These included implant deflation, neuropraxia, bone resorption and late implant exposure. In all cases, sufficient tissue was generated to complete the reconstruction as planned. (a) Implant failure Mechanical failures resulting in implant deflation or valve leakage are exceedingly rare. Exacerbating factors such as trauma, inadvertent implant puncture, or stress fractures occurring in folds of the silastic membrane must be ruled out. Two cases of spontaneous deflation were observed late in the course of expansion, with no detrimental effect on the final reconstruction. In both cases the leak was identified at the junction of the tissue expander and the silastic connecting tube. (b) Compromise of vital structures Thirteen tissue expansions were performed in the cheek and neck. There were no reported cases of
242
airway obstruction or dysphagia. Similarly, six patients underwent eyelid expansion. Ocular discomfort or visual disturbance was not encountered. Modified implant design, using a rigid back wall and expansile anterior portion, was instrumental in regulating the direction of expansion and minimising these potential problems. (c) Neuropraxiu Several factors may predispose to the onset of neuropraxia in association with tissue expansion. Traction may be exerted on a peripheral nerve where a particularly unyielding anatomical arrangement restricts its mobility over a progressively enlarging prosthesis. Alternatively, excessively large volumes or rapid rates of inflation may apply sufficient direct mechanical force to cause nerve compression. When recognised and treated early, before the onset of focal demyelination, the consequences of neuropraxia can be expected to resolve quickly. Despite the large number of expansions performed directly over the path of major nerves, particularly in the cheek and extremities, clinical signs of nerve compression are rare. In the present series of 76 expansions, only three cases of neuropraxia were documented. In two cases, temporary numbness of the sural nerve distribution followed expansion of the posterior calf. In the third, transient numbness was noted in the distribution of the radial sensory nerve following expansion of the dorsum of the hand. This quickly resolved with slight deflation of the implant. Case I. A 37-year-old woman presented with a hyperaesthetic, depressed scar of the left medial calf. Seven years previously she had undergone excision of a malignant melanoma with a 5 cm resection margin. The resulting defect was skin grafted. The patient complained of persistent hypersensitivity of the skin graft which was refractory to treatment with anaesthetic nerve blocks. Through an incision at the posterior margin of the defect, a large subfascial pocket was dissected over the posterolateral calf. A 250 cc tissue expander was placed in the cavity, deep to the course of the sural nerve. Subsequent inflations proceeded uneventfully to a volume of 190 cc before the patient first reported the onset of paraesthesiae over the dorsolateral aspect of the foot. The area of anaesthesia was mapped out. An increase in the vibratory sensory threshold was documented using both a 256 cps tuning fork and an amplitude variable fixed frequency (120 cps) vibrometer. The threshold for two-point discrimination was elevated to 70 mm, compared to 27 mm on the corresponding surface of the contralateral foot.
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Expansion was discontinued and the implant removed. An expanded fasciocutaneous flap was elevated and transposed to resurface the defect. Postoperatively, the paraesthesiae resolved and objective sensory testing confirmed the return of normal sensation.
(d) Intractablepain Intractable pain is an uncommon consequence of tissue expansion. One patient complained of severe, persistent discomfort localised to the soft tissues overlying a forehead expander. There were no associated objective findings of sensory deficits. Pain was first noted in the early postoperative period and the patient was unable to tolerate minimal volumes of inflation. Failure to control the pain following temporary deflation demanded removal of the implant. (e) Haematoma
Haematoma is minimised by meticulous haemostasis and the use of suction drains. When clinical examination reveals the presence of a significant haematoma, immediate surgical drainage and irrigation of the implant cavity are indicated. Secondary consequences such as infection, excessive tension on expanded tissues and capsule formation can be prevented by prompt and adequate treatment. In the present series, a significant haematoma was noted in the early postoperative period in one patient. Case 2. A 25-year-old male sustained a devastating degloving injury to the right hand in March 1985, with amputations of the index finger and distal third of the thumb. A large cutaneous defect of the thenar eminence and dorsal surface of the hand was initially covered with split thickness skin grafts. In August 1985 the patient presented with an adherent, hyperaesthetic skin graft on the dorsum of the hand and a contracture of the first web-space. He was taken to the operating room where a 250 cc tissue expander was inserted into a pocket.on the extensor surface of the distal forearm. The expanded tissues were to provide sensate, durable cover to resurface the first web-space. On the first postoperative day, congestion and poor capillary refill were noted in the skin overlying the implant. The patient was immediately_returned to the operating room where the incision was opened and a large haematoma evacuated. Following thorough haemostasis and irrigation of the pocket, the tissue expander was reinserted. However, continued concern about viability of the overlying skin necessitated removal of the implant and further attempts at tissue expansion were abandoned.
COMPLICATIONS
243
OF SOFT TISSUE EXPANSION
The frequency of percutaneous injections predisposes to infection at the site of the reservoir dome. However, its placement in a separate pocket remote from the tissue expander results in a localised infection which does not necessarily compromise further expansion. Cellulitis was noted over the reservoir dome in one patient. Following treatment with intravenous antibiotics, local signs of inflammation resolved promptly and serial inflations were resumed. Infection of the implant cavity is a more serious complication. Of the three cases documented in our series, only one resolved following treatment with intravenous antibiotics. The remaining two patients required surgical drainage of the subcutaneous pocket and removal of the implant. The soft tissues remained indurated for a prolonged period of time and further attempts at expansion were not made. (g) Bone resorption Forehead expansion in two adult patients resulted in significant resorption of calvarial bone directly beneath the implant. There was no evidence of similar resorption in the remaining six forehead expansions or in six scalp expansions. The same treatment protocol was followed in all cases, and specific exacerbating or causative factors could not
be identified in the two affected patients. The tissue expanders were all placed in a subgaleal pocket, leaving pericranium intact over the surface of the skull. Subsequent inflation to a volume of 300400 cc proceeded uneventfully over a period of 3 months. The calvarial resorption was first noticed upon removal of the implant. An obvious depression in the frontal bone conformed to the exact dimensions and shape of the implant. The resulting frontal contour exaggerated the prominence of the supraorbital ridge, producing a conspicuous skeletal deformity. Case 3. A %-year-old male previously sustained a selfinflicted gunshot wound to the face. Initial treatment consistedof anatomic reduction and rigid internal fixation of all fracture fragments, and primary bone grafting to bony deficiencies of the mandible and maxilla. In October 1984 the patient was admitted for a staged nasal reconstruction. In the first operation, a 250 cc Radovan tissue expander was introduced through a coronal incision into a subgaleal pocket in the forehead. Over the ensuing 3 months, the implant was inflated to a volume of 355 cc. In January 1985 an oblique expanded forehead flap was elevated and draped over a cantilever rib graft to reconstruct the nose. Removal of the expander revealed a shallow, crater-like depression in the frontal bone (Fig. 1). Flattening of the normal forehead convexity amplified the fullness of the glabella and superciliary regions. The bony rim of the cavity was resected to provide a normal forehead contour.
Fig. 1 Figure l-Case 3. Forehead expansion was completed in this 55-year-old patient. (A) Following removal of the expander, a craterlike depression is noted in the frontal bone. The extent of bone resorption is better demonstrated after elevation of the periosteum over the supraorbital region. (B) The depression conforms to the dimensions and shape of the implant, flattening the normal convexity of the forehead.
244
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Fig. 2 Figure 2-Case 4. A 16-year-oldfemale with Poland’s syndrome. (A) The left breast was extremely hypoplastic and the sternal head of the pectoralis major muscle was absent. (B) Multiple red striae, noted following expansion to a total volume of 790 cc.
(h) Striae Striae are bands of thinned, red, wrinkled skin, which result from atrophy and rupture of collagenous fibres in the dermis. They are therefore frequently observed in the skin of the pregnant abdomen and might reasonably be expected to be a common sequela of tissue expansion. In actual fact, however, striae formation was documented in only one of 76 tissue expansions performed in the present series. A standard rate and volume of inflation were employed in this patient, and no other exacerbating factors could be identified.
sion (Fig. 3). The inflation reservoir had initially been placed in a subcutaneous pocket in the posterior neck, remote from the expander itself. The rigidity of the silastic dome, thinness of subcutaneous tissues, and shearing forces generated by repetitive neck motion and contractions of the adjacent sternomastoid muscle, may all have been contributing factors resulting in valve exposure. Direct excision and primary closure of the area of skin necrosis following a repositioning of the valve allowed further expansion to proceed without incident.
Case 4. A 16-year-old girl presented with a congenital deformity of the left breast (Fig. 2). Clinical examination revealed the stigmata of Poland’s sydrome. Syndactyly involving the fingers of the left hand was noted. The left breast was extremely hypoplastic and the sternal head of the pectoralis major muscle was absent. A functioning clavicular head of the pectoralis muscle was identified. The projected location of the submammary fold was mapped out on the patient’s left anterior chest. Through a transverse incision at this level, a 700 cc round tissue expander was inserted into a large subcutaneous pocket. Subsequent inflations proceeded at a rate of 100 cc weekly to a total volume of 790 cc. Striae formation was first noted in the last few weeks of expansion. The tissue expander was subsequently removed and the reconstruction completed using a custom-made prosthesis with a moulded attachment to fill out the missing portion of the pectoralis muscle. The striae have persisted.
(i) Value exposure
Skin erosion over the reservoir dome was observed in one patient undergoing cheek and neck expan-
Fig. 3
Figure 3-The reservoir dome in this patient was placed in a subcutaneous pocket in the posterior triangle of the neck. Progressive erosion of overlying soft tissues resulted in exposure.
245
COMPLICATIONS OF SOFT TISSUE EXPANSION
(j) Implant exposure
Exposure of the silastic implant was the most frequently observed complication of tissue expansion, occurring in 20% of all cases. Three major causative factors were identified. These included dehiscence of the incision, erosion through inadequate tissue cover or pressure necrosis of soft tissues over a persistent fold in the silastic envelope. In an effort to prevent early dehiscence of the incision, several measures were employed routinely. These included the placement of incisions at the periphery of the implant pocket using a staggered, two-layer closure, and delaying implant inflation until sufficient time had passed for the wound to heal. Nonetheless, incisional dehiscence was the most common cause of implant exposure and generally occurred early in the course of expansion. The consequences were therefore serious
and the final reconstruction was compromised significantly delayed in most cases.
or
Case 5. A 31-year-old man had previously sustained a traumatic avulsion of the right great toe. Primary treatment included a revision of the amputation at the proximal phalangeal level and skin grafting of the cutaneous defect on the dorsal aspect of the foot (Fig. 4). The patient subsequently developed an extremely painful amputation stump with an adherent, hyperaesthetic skin graft. Through an incision between the first and second metatarsal along the margin of the skin graft, a large subfascial pocket was dissected on the dorsolateral surface of the foot. Particular care was taken to avoid any undermining of the graft. A 100cc tissue expander was placed in the pocket and the incision closed in two layers. In the third postoperative week, serial inflations were started at a rate of 10 cc weekly. Dehiscence of the
Fig. 4 Figure 4-Case 5. A 31-year-old male with a hyperaesthetic skin graft on the dorsum of the right foot. (A) An incision was inappropriately made along the margin of the previous scar, as indicated by the dotted line. The expander was placed in a subfascial pocket on the dorsolateral surface of the foot. (B) Dehiscence of the incision and exposure of the implant occurred in the fifth postoperative week.
246 incision occurred in the fifth week, at a total volume of only 35 cc. The patient was immediately admitted for a course of rapid expansion under close supervision. However, the early onset of secondary infection in the implant cavity prompted immediate removal of the tissue expander. The amputation was eventually revised at the base of the first metatarsal, permitting excision of the graft and scar tissue, and direct closure of the defect. Previously scarred or irradiated soft tissues tolerate expansion poorly and should be avoided whenever possible. Both tissue extensibility and blood supply are limited, causing a palpable tenseness and blanching in the skin with minimal increments of inflation. Thinning and necrosis of skin with subsequent implant exposure were observed in two patients. In both cases exposure occurred late in the course of expansion at near
maximal volumes of inflation, Sufficient tissue was available to complete the planned reconstruction with expanded flaps. A third, and very common, cause of implant exposure is related to a fundamental deficiency in the design of tissue expanders. The envelope consists of a redundant surface area of silastic membrane with limited inherent extensibility. Rather than expanding, the implant functions as an empty folded bag which gradually unfurls as it fills. Irregularities in the surface contour persist until near maximal volumes of inflation. Clinically, prominent folds in the silastic envelope cause focal pressure necrosis and progressive erosion in the overlying soft tissues. Measures to eradicate these folds, such as manipulation of the implant, rapid inflation or deflation, proved ineffective. The frequency of soft tissue erosion and implant exposure varied with the anatomical site of expansion. The thickness of the skin and subcutaneous tissues in the trunk and extremities offered some protection. More importantly, the inclusion of an additional vascularised layer of fascia or muscle between the implant and cutaneous surface resulted in the overlying skin being less susceptible to pressure necrosis. Even under such favourable circumstances, however, skin erosion and implant exposure were observed in one patient undergoing breast expansion. Case 6. A 43-year-old woman presented with a right postmastectomy deformity. Two years previously the patient had undergone a modified radical mastectomy for breast carcinoma, followed by 6 months of chemotherapy. Clinical examination revealed a single oblique scar over the right chest, soft, pliable skin and a functioning pectoralis major muscle. She was considered a good candidate for breast expansion and reconstruction.
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Through an incision in the previous scar, a 700 cc round tissue expander was introduced into a submuscular pocket. Subsequent expansion proceeded uneventfully to a volume of 615 cc when a prominent buckle was first noted in the medial aspect of the implant, superior to the mastectomy scar. Over the ensuing week, the overlying skin became erythematous and mildly tender. Failure of this condition to resolve following treatment with intravenous antibiotics suggested the presence of fat necrosis. Progressive thinning of the soft tissues eventually culminated in complete erosion and exposure of the implant (Fig. 5). An attempt was made to salvage the tissue expander in this patient. She was immediately taken to the operating room where the implant was partially deflated. The capsule surrounding the exposure site was found to be friable and necrotic, requiring extensive debridement. The ulcer itself was excised in elliptical fashion and closed directly. However, the wound continued to break down and the implant was removed 3 days later. The cheek and neck were particularly susceptible to focal pressure necrosis and implant exposure. Contributing factors included the thinness of overlying skin and subcutaneous tissues and constant shearing forces generated by repetitive neck and jaw motion. More importantly, gravitational pooling of injected saline in the most dependent portion of the implant predisposed of differential expansion and inferior migration of the entire tissue expander. Buckling of the implant occurred where further migration was obstructed, as in the inferior margin of the mandible and over the clavicle. Exposure in these anatomically predictable sites was noted in five cases.
Fig. 5 Figure S-Case 6. Despite submuscular placement of the implant in this patient undergoing breast expansion, a persistent fold in the silastic envelope resulted in focal pressure necrosis and eventual exposure.
241
COMP‘Ll:CATIONS OF SOFT TISSUE EXPANSION
Fig. 6 Figure &Case 7. A 55-year-old woman with a post-traumatic scar. (A) The defect measured 25 x 10 cm and involved the ieft cheek, chin and lower eyelid. (B) Through a rhytidectomy incision, a large subcutaneous pocket was dissected, as indicated by the dotted line. The intended location of the implant is demonstrated. (C) The problems associated with cheek and neck expansion are well illustrated here. Gravitational pooling of saline resulted in disproportionate expansion and thinning of skin at the lower pole of the implant. The entire expander migrated inferiorly and buckled over the clavicle, causing erosion with necrosis of overlying soft tissues. (D) The result, 3 months postoperatively.
248 Case 7. A %-year-old woman was referred for treatment of a post-traumatic plaque-like scar of the left cheek, measuring 25 x 10 cm (Fig. 6). The defect consisted of thick, non-pliable cicatrix which was associated with an ectropion of the left lower eyelid. Through a rhytidectomy incision, skin flaps were elevated in a plane immediately superficial to the SMAS. A large subcutaneous pocket was developed, extending well into the neck but avoiding all areas of scarring. A rectangular tissue expander was inserted and the reservoir dome was placed in a remote subcutaneous pocket over the sternomastoid muscle. In the first postoperative week, erythema and thinning of skin were noted over the reservoir dome. The valve became exposed shortly thereafter. All necrotic and atrophic skin was promptly excised and the defect closed primarily. The valve was repositioned over the mastoid process and serial inflations were resumed. Injected fluid pooled in the dependent portion of the implant, causing differential expansion and thinning of the overlying tissues. The entire expander migrated inferiorly as far as the clavicle where a persistent fold developed in the silastic envelope. Overlying tissues eventually eroded, exposing the implant and precluding further expansion. The patient was taken to the operating room where necrotic skin was excised and the implant removed. Remaining expanded tissue was incorporated in a medially-based cheek/neck rotation flap. The dimensions of the flap were sufficient to permit excision and resurfacing of most of the scar, leaving an 8 x 3 cm residual defect.
Discussion The concept of soft tissue expansion by gradual inflation of a prosthesis was initially adapted for clinical use in breast reconstruction (Radovan, 1978). It offered the potential to generate a required amount of soft tissue while permitting some control of the eventual size and shape of the reconstructed breast mound. The technique was simple and excellent results could be anticipated. In particular, reviews of clinical series demonstrated minimal complication rates ranging from 0 (Argenta et al., 1983a) to 14% (Radovan, 1982). Tissue expansion became firmly established as a reconstructive option for the post-mastectomy patient. More recently, extensions of these same principles and refinements in technique prompted the adaptation of tissue expansion for an increasing variety of indications in multiple anatomical sites, including the face (Argenta et al., 1983b), scalp (Manders et al., 1984a; Leonard and Small, 1986), and extremities (Sasaki, 1984; Mackinnon and Gruss, 1985; Mackinnon and Dellon, 1987). The increase in scope of applications has also been
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associated with an increased incidence of complications. In anatomical regions excluding the breast, Argenta et al. (1985) documented complications in 24% of their first 30 cases. Similarly, a review of 41 expansions performed for a wide spectrum of problems revealed an overall complication rate of 40% (Manders et al., 1984b). The results of tissue expansion vary greatly with the anatomical site. Regional differences in skin laxity, vascular supply, thickness of subcutaneous tissues and the presence or absence of an additional layer of muscle or fascia contribute to the variability. The present clinical series comprises 76 expansions, 53 of which were performed in the head and neck or the extremities. The incidence of complications was particularly high in these two areas, occurring in 50% and 47% of cases respectively. The remaining expansions were restricted to the chest and trunk and were distinguished by consistently good results and minimal complications. The severity of complications and their impact on the final outcome of treatment are more difficult to evaluate: 38% of patients undergoing tissue expansion sustained some form of complication requiring a revision in the original treatment plan. These revisions included the implementation of ancillary medical or operative procedures, temporary reductions in the rate or quantity of serial inflations, and premature discontinuation of expansion. However, the consequences rarely involved loss of tissue and the intended reconstructions were completed successfully in 83% of cases. It is particularly important to consider the quality of reconstruction that is now available as a result of tissue expansion. Unlike other reconstructive techniques, expansion provides a surplus of locally available tissue with the required colour, texture and hair-bearing characteristics. Sufficient tissue is generated to resurface both donor and recipient sites simultaneously, thus minimising the donor site deformity. The final result is frequently far superior to that obtained by alternative means of reconstruction. In the future, efforts to decrease the overall complication rate must be directed at the anticipation of certain problems and their prevention. Emphasis on implant modifications and refinements in surgical technique designed to minimise the risk of exposure would influence the results of tissue expansion most dramatically. Early incisional dehiscence can be averted by the employment of radial or marginal incisions which are placed well away from the site of expansion. A staggered
249
COMPLICATIONS OF SOFT TISSUE EXPANSION
double-layer closure restricts migration of the implant under the incision, and sufficient time must be allowed for the incision to heal prior to commencement of serial inflations. Erosion and pressure necrosis of soft tissues over the implant are more difficult to control. Although previous scarring and atrophy in expanded tissue were causative factors in two cases, the majority of implant exposures occurred in uninjured and well vascularised skin. Certain anatomical sites, such as the cheek and neck, were particularly susceptible. The relative thinness of skin and subcutaneous tissues in this area, and gravitational pooling of saline resulting in differential expansion and implant migration may all have contributed. Most importantly, the formation of persistent buckles in the implant is an ominous sign which is frequently resistant to external manipulation. Buckling of the silastic membrane is an inherent property of all tissue expanders currently available. Modifications in implant design incorporating an expansile, distensible membrane would most significantly alter the frequency of observed complications.
References Argenta, L. C., Marks, M. W. and Grabb, W. C. (1983a). Selective use of serial expansion in breast reconstruction. Annals ofPlastic Surgery, 11, 188. Argenta, L. C., Watanabe, M. J. and Giiabb, W. C. (1983b). The use of tissue expansion in head and neck reconstruction. Annals of Plastic Surgery, 11, 3 1. Argenta, L. C., Marks, M. W. and Pasyk, K. A. (1985). Advances in tissue expansion. Clinics in Plastic Surgery, 12, 159. Leonard. A. G. and Small. J. 0. (1986). Tissue exuansion in the treatment of alopecia. ‘British‘Jourkl of Plastic Surgery, 39, 42.
Macklon, S. E. and Dellon, A. L. (1987). Soft tissue expansion in hand reconstruction. British Journal of Hand Surgery, 12B, 73.
Macklnnon, S. E. and Gruss, J. S. (1985). Soft tissue expanders in upper limb surgery. Journal of Hand Surgery, IOA, 749. Maaders, E. K., Graham III, W. P., Schenden, M. J. aad Davis, T. S. (1984a). Skin expansion to eliminate large - scalp_ defects. Annals of Plastic Surgery, 12, 305. Manders. E. K.. Schonden. M. J.. Furrev. J. A.. Hetzler. P. T.. Davis,‘T. S.’ and Graham Iii, W. fi: (198hb). Soft tissu; expansion : concepts and complications. Plastic and Reconstructive Surgery, 14,493. Radovan, C. (1978). Reconstruction of the breast after radical mastectomy using a temporary expander. Plastic Surgery Forum. 1,41.
Radovan, C. (1982). Breast reconstruction after mastectomy using the temporary expander. Plastic and Reconstructive Surgery, 69, 195. Sasakl, G. H. (1984). Extremity soft tissue reconstruction. In Habal, M. (Ed.) Advancesin PlasticandReconstructive Surgery,
Vol 1. Chicago: Year Book Medical Publishers.
Vistnes, L. M., Ksander, G. A. and Kosek, J. (1978). Study of
encapsulation of silicone rubber implants in animals. A foreign body reaction. Plastic and Reconstncctive Surgery, 62, 580.
The Authors 0. Aatooyshyn, MD, FRCS(C), Clinical fellow, Division of Plastic Surgery, Sunnybrook Medical Centre, Toronto. J. S. Gruss, MB, FRCS(C), Consultant and Head, Division of Plastic Surgery, Sunnybrook Medical Centre, Toronto. S. E. Macklnnon, MD, FRCS(C), Consultant, Division of Plastic Surgery, Sunnybrook Medical Centre, Toronto. R. Zuker, MD, FRCS(C), Consultant and Head, Division of Plastic Surgery, Hospital for Sick Children, Toronto. Requests for reprints to: Dr J. S. GNSS, Division of Plastic Surgery, Sunnybrook Medical Centre, 2075 Bayview Avenue, HG 948, Toronto, Ontario M4N 3M5, Canada. Paper received 7 April 1987. Accepted 7 July 1987.
Discussion by Mr Oliver Fenton, FRCS There can be few areas of surgery where an unchanged complication rate of 40% over a 10 year period has been accompanied by an increasing acceptance of the procedure by clinicians. The two main reasons for this are the quality of reconstruction that can be achieved using tissue expanders and the artificial nature of this complication rate. Very few complications will prevent satisfactory completion of a reconstruction and in most cases problems such as exposure and infection can be controlled until expansion is complete. Surgical experience should have reduced the complication rate but this has been offset by the widening application of tissue expanders, as highlighted in this paper. This has been compounded by a failure to alter both the basic shape of the original implant and the surgical approach. This paper goes some way towards analysing problems in implant design and use, but it also perpetuates several misconceptions. Chief amongst these are base plates, directional expansion, radial incisions, delaying inflation until the wound has “healed”, and placing the expander outside the area to be excised. Radovan’s original implants were thick-walled, rectangular, folded and incorporated a base plate, and in my view are the antithesis of an implant designed for skin expansion. The base plate is supposed to give direction to the expansion and this idea of “directional” expansion has been further developed by several manufacturers. This ignores Newton’s Third Law of action and reaction-direction is provided by the base on which the
250 entire implant sits and cannot be achieved by an integral rigid plate. Such an implant will expand almost as well if turned upside down, except for the constraints on lateral expansion imposed by the base plate. Base plates serve no useful function and are a significant cause of complications, especially on curved surfaces such as the head and neck and limbs, and prevent the expander from recruiting the maximum amount of skin by limiting lateral expansion. Any “direction” that occurs is at the expense of this recruitment and will result in thinning of the overlying skin, as best displayed in implant exposure due to “knuckling”. The authors suggest that incisions radial to the expander reduce the likelihood of wound exposure. Expansion occurs in all directions over an implant and if a wound is caught up in the expansion process it is liable to dehiscence whatever its direction. This is more likely when the incision is placed next to an immobile area such as the ear or a scar, as the pull on the wound cannot be dispersed. The only sure way to prevent wound dehiscence is to make sure the wound is well away from the site for expansion. However, my main disagreement with Dr Antonyshyn’s paper concerns the timing of expansion. Delaying expansion by a few weeks does not allow wound “healing” to occur to any useful degree. It does, however, allow the development of a capsule around the implant, so that much of the force of expansion is wasted against the capsule rather than the skin. I believe that this can cause considerable discomfort to the patient and certainly
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prolongs the time taken for full expansion. My own practice is to inflate to the limits of safety on the operating table and then continue expansion on a daily basis when logistically possible. As the authors point out, almost all current implants rely on an unfolding of the silicone envelope to produce expansion, with resultant knuckling and frequent exposure. The better quality implants are capable of expansion to 6 times their stated volume and since 1985 I have been requesting two manufacturers to capitalise on this fact and produce flat, pliable implants. However, when flat expanders did appear, from another company, they incorporated a firm rim that cut into the base of the expanded skin with predictable results. I agree with the authors that modifications to current designs are long overdue, and we have designed a soft, flat, croissantshaped expander that we have used for the past 3 months with great success, to the extent that we will cease to use conventional expanders once our stocks run out. These can be inserted through a small remote incision and then positioned using a “flotation-displacement” principle. The croissant shape embraces the area to be excised and dispenses with the need for additional skin incisions to make optimum use of the expanded skin. Much the same effect can be achieved by placing part of the expander under the defect, disregarding the expansion of the defect itself. Tissue expansion will not realise its full potential until the complication rate is consistently below 10%. I believe we will achieve this in the next 2-3 years.