Biomedical subjects
Publications and source records attributed to J W Siebert.
Reconstruction of challenging surgical problems has undergone a dramatic evolution over the past quarter of a century. Microsurgical correction of facial contour deformities is a prime example of how far microsurgical reconstruction has evolved. This article discusses the current surgical techniques.
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Multiple microvascular anastomotic techniques have been described with varying rates of success. This experimental study presents the results of a comparison of three types of venous microanastomotic techniques: the Unilink system, the sleeve technique, and the suture technique. Twenty male Sprague-Dawley rats, 40 femoral veins, were used for this study. In vivo observation and microvasculography demonstrated that patency rates between the Unilink system and suture techniques were comparable (p > 0.05) and were significantly superior to the sleeve anastomosis (p < 0.05). The anastomotic time for the sleeve technique was significantly shorter than for the suture technique (p < 0.001). Compared with suture and sleeve anastomoses, the anastomotic time employing the Unilink system was significantly the shortest (p < 0.001). The Unilink system proved to be the fastest method with the highest patency rate. These results suggest that the use of the Unilink system is superior with regard to anastomotic time and patency rate, when compared to suture and sleeve techniques for venous microanastomosis.
Parascapular free flaps traditionally have been designed obliquely across the back, corresponding to the descending branch of the circumflex scapular artery. The donor site of this workhorse flap has the drawback of a widened and frequently hypertrophic scar. In searching for aesthetic improvements in the donor site, we have progressively rotated the axis of this flap in an anterior direction. The end result of this modification is the flap we report here: the inframammary extended circumflex scapular flap. This flap has a longitudinal axis of rotation lying curvilinearly from the inframammary fold to the circumflex scapular artery within the triangular anatomic space. We have used this flap in 20 patients over the past 2 years. The vast majority of these cases were deepithelialized flaps with customized extensions of dorsal thoracic fascia to correct facial asymmetry. We feel that the inframammary extended circumflex scapular artery flap donor-site scar is well hidden within the inframammary fold, and that the unavoidable widening and hypertrophy of parascapular and scapular flap donor-site scars were minimized compared with traditional flap designs.
Poland's syndrome comprises a spectrum of chest-wall deformities affecting, to various degrees, the rib cage, the chest-wall muscles, the neurovascular structures of the ipsilateral arm, and the overlying breast. This study details our experience with nine female Poland's syndrome patients who had chest-wall and breast asymmetry corrected by microvascular free-tissue transfer. Nine female patients with Poland's chest deformity underwent 12 microvascular free flaps between 1989 and 1994. Donor sites for free-tissue transfer included eight transverse rectus abdominis flaps, two superior gluteal flaps, one inferior gluteal flap, and one contralateral latissimus dorsi flap. Recipient vessels were branches of the subscapular vascular axis in all patients. Patients' ages ranged from 18 to 47 years at the time of reconstruction. Chest-wall and breast asymmetry varied from accompanying severe pectus and rib cage deformities to isolated breast involvement. Complications were limited to a superior gluteal flap loss due to anomalous subscapular venous drainage. This patient underwent a successful second superior gluteal flap reconstruction utilizing the cephalic venous outflow system. Chest-wall and breast symmetry was restored in all patients. This study demonstrates that microsurgical reconstruction of chest-wall and breast asymmetry in Poland's syndrome yields excellent results with a high degree of patient satisfaction. Careful intraoperative assessment of the recipient vessels prior to flap transfer is mandatory. Because Poland's chest-wall deformity may include anomalies of the vascular system, preoperative vascular assessment with duplex ultrasonography should be considered in all patients, and use of preoperative angiography or venography in selected patients also appears justified.
The vascular supply of the Le Fort I osteotomy segment was studied by utilizing standard latex injection techniques. Anatomic dissections in 10 fresh cadavers demonstrated interruption of the descending palatine arteries with preservation of the ascending palatine branch of the facial artery and the anterior branch of the ascending pharyngeal artery within the attached posterior palatal soft-tissue pedicle in all specimens following Le Fort I maxillary osteotomy. These ascending arterial branches entered the soft palate at a position approximately 1 cm posterior to the pterygomaxillary junction, which was disrupted during the Le Fort I maxillary osteotomy. Separate ink injections of total maxillary osteotomy segments confirmed vascular perfusion of the ipsilateral hemimaxillary segment by the ascending palatine artery. Thus vascular supply of the mobilized Le Fort I maxillary segment is by means of the ascending palatine branch of the facial artery and the anterior branch of the ascending pharyngeal artery in addition to the rich mucosal alveolar anastomotic network overlying the maxilla.
The postoperative outcome of hand flexor tendon repair can be complicated by adhesions between the repair site and surrounding tissue. To date, the biology of hand flexor tendon wound healing remains controversial--both intrinsic (resident tenocyte) and extrinsic (tendon sheath fibroblast and inflammatory cell) processes may contribute to repair. Transforming growth factor beta-1 is a cytokine that plays multiple roles in wound healing but is also implicated in the pathogenesis of excessive scar formation. This study examines the activation of transforming growth factor beta-1 mRNA in a rabbit zone II flexor tendon wound-healing model. Forty New Zealand White rabbit forepaws underwent complete transection and repair of the middle digit flexor digitorum profundus tendon in zone II. Tendons were harvested at increasing time intervals (1, 3, 7, 14, 28, and 56 days) and analyzed by in situ hybridization and immunohistochemistry to determine the expression patterns of transforming growth factor beta-1. A small number of tenocytes exhibited expression of transforming growth factor beta-1 mRNA at baseline in nonwounded control tendon specimens. The surrounding tendon sheath in these control specimens also revealed low numbers of fibroblasts and inflammatory cells expressing transforming growth factor beta-1 mRNA. In contrast, flexor tendons subjected to transection and repair exhibited increased signal for transforming growth factor beta-1 mRNA in both resident tenocytes and infiltrating fibroblasts and inflammatory cells from the tendon sheath. These data demonstrate that (1) normal unwounded tenocytes and tendon sheath cells are capable of transforming growth factor beta-1 production, (2) this cytokine is activated in the tendon wound environment, as evidenced by mRNA upregulation, and (3) the upregulation of this cytokine in both "intrinsic" tenocytes and "extrinsic" tendon sheath fibroblasts and inflammatory cells supports dual mechanisms for tendon repair. Because transforming growth factor beta-1 is thought to contribute to the pathogenesis of excessive scar formation, the findings presented here suggest that perioperative biochemical modulation of transforming growth factor beta-1 levels may help limit flexor tendon adhesion formation.
Transforming growth factor (TGF)-beta isoforms (TGF-beta 1, -beta 2, and -beta 3) regulate cell growth and differentiation and have critical regulatory roles in the process of tissue repair and remodeling. Signal transduction for TGF-beta function is transmitted by a heteromeric complex of receptors consisting of two serine/threonine kinase transmembrane proteins (RI and RII). We have previously shown that each TGF-beta isoform is widely expressed in a distinct spatial and temporal pattern throughout the processes of excisional and incisional wound repair. As the presence of TGF-beta receptors determines cellular responsiveness, we have currently examined, by immunohistochemistry, the localization of RI (ALK-1, ALK-5) and RII throughout repair of full-thickness excisional wounds up to 21 days after wounding. The expression of RI (ALK-5) and RII co-localized in both the unwounded and wounded skin and was present in the same cell types as TGF-beta ligands. However, immunoreactivity for TGF-beta receptors, throughout repair, occurred 1 to 5 days later than TGF-beta isoform immunostaining. This implies that the presence of TGF-beta ligands may up-regulate TGF-beta receptors for function and/or may reflect a lag due to local processing of latent TGF-beta. As observed for the immunohistochemical localization of TGF-beta isoforms in unwounded skin, RI and RII were expressed throughout the four layers of the epidermis, showing a wavy pattern of slight to moderate immunostaining, and hair follicles, sweat glands, and sebaceous glands were moderately immunoreactive. The extracellular matrix, fibroblasts, and blood vessels in the dermis were not immunoreactive. After injury, as observed for TGF-beta ligands, RI and RII expression was increased in the epidermis adjacent to the wound and the epithelium migrating over the wound was completely devoid of TGF-beta receptor immunoreactivity until re-epithelialization was completed by day 7 after wounding. The dermis was only slightly immunoreactive for RI and RII until day 5 when, immediately under the wound, immunostaining for fibroblasts, connective tissue cells, and newly forming vasculature began to increase and remained intense until day 14. Consistent with the role for TGF-beta in scarring, numerous fibroblasts, ostensibly active in the production of extracellular matrix components, continued to be slightly immunoreactive for RI and RII at 21 days. The ALK-1 (TSR-1) type I receptor, which binds both activin and TGF-beta, showed slight immunostaining early in repair (days 1 to 7) that progressively became more intense later in repair after day 10 and through day 21. This suggests that there may be a switch to a different type I receptor, implying different functions for the ALK-1 and ALK-5 receptors. The concomitant expression of TGF-beta isoforms and their signal-transducing receptors denote potential spatial and temporal activity of TGF-beta. Thus, although TGF-beta ligand is present, TGF-beta would not function in wound repair until a later time when RI and RII appear. This information should aid in the development of receptor antagonists as a therapeutic approach to scarring and fibrosis. In addition, these studies underscore the importance of defining the expression of proteins in vivo to establish a basis for the analysis of mechanisms in vitro.
Based upon our experience with microvascular reconstruction of facial contour problems in 116 patients, we have developed an operative approach that emphasized both donor site and facial aesthetics and reliably restores symmetry. This allows correction of the obvious facial symmetry along the jawline as well as the more subtle problems in the midface, temporal, and periorbital areas. A state-of-the-art approach for reconstruction of facial deformities should include standard craniofacial techniques with or without bone expansion followed by soft-tissue microvascular reconstruction when required. This marriage of both hard and soft tissue maximizes the aesthetic results by restoring facial harmony in these difficult craniofacial patients.
Hypertrophic scarring is characterized by disordered collagen fibrils. In order to determine whether this is, in part, a result of changes in the population of proteoglycans that are thought to be involved in regulation of collagen fibril formation, we have compared PGs from post-burn normal and hypertrophic scar tissue, as well as from human dermis and epidermis. Efforts to separate the two major iduronic acid-containing proteoglycans, decorin [PG(IdoA)-II] and biglycan [PG(IdoA)-I], for quantitation were not successful. The different N-terminal sequences of these two iduronic acid-containing proteoglycans PG(IdoA-I and -II were utilized to estimate the relative amounts in the above PG(IdoA) preparations. Normal scar, dermis and epidermis were all found to contain primarily decorin with low (< 10%) levels of biglycan relative to decorin. In contrast, iduronic acid-containing proteoglycans from hypertrophic scar were found to be approximately 30% biglycan [PG(IdoA)-I]. This may be a proximal cause of altered collagen fibrils, or may result in alterations in the sequestration of growth factors, which then results in changes in collagen that effect the appearance of the scar. 1966 Elsevier Science Ltd.
A new technique for microvascular four-stitch sleeve anastomosis of arteries is described. Modifications from previously described techniques include absence of suture material within the arterial lumen, and a decreased proximal to distal artery overlap. In 40 rat arterial anastomoses, 100% patency without evidence of stenosis or early aneurysm formation was seen up to 6 weeks postoperatively by in vivo observation, arteriography and Doppler flow study. This new anastomosis was also successful in repairing two clinical cases of complete radial artery transection as evident from physical examination and doppler flow study. We believe that this new four-stitch sleeve anastomosis is faster and easier to perform and has patency and flow characteristics similar to those of the conventional end-to-end anastomosis.
Restoring soft-tissue contour in patients with facial asymmetry is a difficult problem for plastic surgeons. We report our experience with 57 consecutive patients who underwent 60 microvascular free flaps for the correction of facial asymmetry between July of 1989 and June of 1994. Etiologies of facial asymmetry included hemifacial microsomia, hemifacial atrophy, postradiation sequelae, burns and trauma, and selected congenital anomalies. Thirty-eight patients were reconstructed with a customized parascapular flap incorporating extensions of dorsal thoracic fascia. Other donor sites utilized were as follows: six superficial inferior epigastric flaps, three myocutaneous flaps, seven muscle flaps, and six fasciocutaneous flaps with bone. To correct facial asymmetry, the recipient site was dissected through a limited preauricular incision whenever feasible, and the superficial temporal artery and vein were used as recipient vessels. A monitoring skin paddle was rarely used. There were no flap losses in this series. Six patients experienced a postoperative hematoma, three of which were drained at the bedside. Limited skin slough occurred in three patients. No donor-site complications other than hypertrophic scarring were encountered. Flap revisions were performed in 22 of the 57 patients to maximize aesthetic results. Based on our experience, we feel that the operative approach presented here allows excellent and stable correction of facial asymmetry due to a variety of etiologies. Furthermore, this technique is applicable to other congenital craniofacial deformities such as Treacher-Collins syndrome and orbital-facial clefts.
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The correction of facial asymmetry in complex craniofacial malformations presents a challenging problem for reconstructive surgeons. Deficiencies of both the facial skeleton and the overlying soft tissue must be addressed to achieve the optimal reconstructive result. We present our experience with a minimum of 1-year follow-up over a 5-year period with 19 patients who initially underwent standard facial skeletal reconstruction and subsequently required microsurgical soft-tissue reconstructions for final correction of facial contour. From July of 1989 to June of 1994, 19 patients with craniofacial malformations underwent microsurgical correction of facial contour using 21 free flaps. The underlying malformations included 15 hemifacial microsomias, 2 orbitofacial clefts, 1 congenital temporomandibular joint ankylosis with micrognathia, and 1 Tessier no. 30 (lower midline mandibular) cleft. Sixteen patients had previous facial skeletal correction using craniofacial techniques. Age at operation ranged from 6 to 27 years. Twenty-one microvascular flaps were used on the 19 patients: 19 deepithelialized parascapular flaps, 1 superficial inferior epigastric flap, and 1 fibula with soleus muscle and large skin paddle for a severe Tessier no. 30 facial cleft with severe micrognathia. Of the 15 patients with hemifacial microsomia, 10 were treated with parascapular fasciocutaneous flaps, 3 with parascapular flaps with bone, 1 with a parascapular flap with teres major muscle for additional bulk, and 1 with a superficial inferior epigastric flap. Complications were two limited hematomas drained at the bedside and a partial skin paddle slough of the fibula flap. Correction of facial contour in complex craniofacial malformations is possible using microsurgical techniques. These free flaps "camouflage" the underlying skeletal deformity that persists despite traditional skeletal reconstruction while restoring symmetrical facial contour. We recommend the marriage of both skeletal and microsurgical soft-tissue reconstructions to achieve the optimal aesthetic result for craniofacial contouring in these challenging patients.
Bilateral facial contour deformities are difficult reconstructive problems to correct. This paper summarizes our experience with five adult patients who were operated on for the correction of bilateral contour deformities. The etiologies of the contour deformities were one case of systemic lupus erythematosus, three cases of hemangioma/lymphangiomas, and one case of systemic lipodystrophy. Patient ages at the time of surgical correction ranged from 19 to 65 years. In two patients, staged microvascular free-tissue transfers were performed. In three patients, a single free flap was used for reconstruction. Seven microvascular free flaps were used to reconstruct facial contour: three superficial inferior epigastric flaps and four inframammary extended circumflex scapular flaps. In three patients, recipient sites were dissected by means of a limited preauricular incision, and the superficial temporal artery and vein were utilized as recipient vessels. The two remaining patients underwent free-tissue transfer to branches of the external carotid system. There were no flap losses in this series. Follow-up ranged from 1 to 4 years. A stable restoration of facial contour was achieved in all five patients. Microsurgical correction of soft-tissue contour problems is possible in bilateral deformities, and superior results are easier to achieve than in unilateral facial contour deformities. Either single or staged reconstructions can restore facial contour depending on the distribution of soft-tissue requirements.
Proteoglycans (PGs) were extracted from human hypertrophic and normal scar tissues from two different stages of maturation after burn injury, under dissociative conditions (4 M guanidinium chloride containing proteinase inhibitors). The extracts were fractionated by ion-exchange chromatography, followed by ethanol precipitation, to give PG-containing iduronic acid (PGIdoA). The size of the PGIdoA decreased with the maturation of scars. Glycosaminoglycan (GAG) chains from PGIdoA were released by alkaline borohydride treatment, and their M(r) values were evaluated by polyacrylamide gel electrophoresis. The M(r) values for PGIdoA protein cores of the hypertrophic scars (5+ years and 2-5 years) and normal scar (5+ years and 2-5 years) were 22.6, 25, 19 and 21 kDa, respectively. The iduronic acid content of PGIdoA from both types of scar increased in their maturation phase. The M(r) values of PGIdoA decreased with maturation. PGIdoA carried the sulfate group mainly attached at C-4 of the 2-amino-2-deoxy-D-galactose residue. The NH2-terminal amino acid sequences of all the PGIdoA were similar to those of normal human skin or bone PG II (decorin) (i.e., Asp-Glu-Ala-B-Gly-Ile-Gly-Pro-Glu-Val-Pro-Asp-Asp-Arg).
This study assessed the postoperative microvascular hemodynamics in end-to-side arterial anastomoses of varied angles in order to determine whether the angle of the anastomosis affects arterial flow. Thirty male rats were divided into three groups of ten. Carotid to carotid end-to-side anastomoses were performed with anastomotic angles of 45, 90, and 135 degrees. Postoperative flow was assessed using high frequency pulsed Doppler ultrasound (HFPDU) at 30 and 120 min postoperatively. Measurements at 30 min demonstrated significant differences in flow, with the 45 degrees grafted vessels utilizing 56.5% of total carotid flow, and the 90 degrees and 135 degrees anastomoses appropriating 46.5% and 43.2% of flow, respectively (comparing 45 degrees to both 90 degrees, P < 0.05, and 135 degrees, P < 0.002). The change from baseline in 45 degrees and 90 degrees groups dissipated over a 2 hr postoperative period, but flow in the grafted vessels in the 135 degrees group continued well below 50% at 39.9% (comparing to both 45 degrees and 90 degrees, P < 0.001), thereby displaying a significant difference in the postoperative arterial flow of varied angled microanastomoses.
Microvascular techniques are important in making routine anastomoses quicker and difficult anastomoses easier. The authors have developed three types of sleeve anastomoses for different size vessels: a three-stitch sleeve anastomosis, four-stitch sleeve anastomosis, and sidecut sleeve anastomosis. Arteriography, in vivo observation, pulsed ultrasound Doppler hemodynamic study, histology, and ultrastructural examination with scanning electron microscopy at 2 to 90 days demonstrated that all three groups of sleeve anastomoses do not stenose, do not show hemodynamically significant vasospasm, and are not complicated by aneurysm formation by 90 days. The hemodynamics were comparable to control sutured anastomoses at 2 to 4 hr postoperatively. The sleeve anastomoses left no suture material within the vessel lumen. Reendothelialization was comparable with controls at 14 days, and the long-term patency rates were similar (p > 0.05). The operative times for all three types of sleeve anastomoses were significantly shorter than sutured control anastomoses (p < 0.001). Although limited by available vessel length and diameter, the sleeve anastomosis is a useful technique for the microsurgeon.