John W. Siebert

A new vascularized bone graft for scaphoid nonunion

Nonunion and avascular necrosis after scaphoid fractures continue to be problem sequelae because of unrecognized injuries, inadequate immobilization techniques, or insufficient treatment time. Screw fixation and inlay bone grafting techniques remain the options of choice, with successful union reported in approximately 90% of patients. However, prolonged immobilization with plaster up to 4 to 6 months is required with conventional techniques. With the use of standard latex injection techniques with vascular filling of vessels to less than 0.1 mm diameter in ten fresh cadaver dissections, we discovered a consistent vascularized bone graft source from the distal dorsoradial radius. We have used this vascularized bone graft source with good results in eleven patients with long-standing nonunion of the scaphoid. It is technically easy and seemingly offers the advantages of a decreased period of immobilization and a higher union rate.

Latissimus dorsi musculocutaneous flap without muscle

The possibility of raising the cutaneous island of the latissimus dorsi musculocutaneous flap without muscle based on only one cutaneous perforator is presented in this paper. An anatomic study performed in 40 fresh cadaver specimens injected with colored latex demonstrated that the vertical intramuscular branch of the thoracodorsal artery gives off two to three cutaneous branches (perforators) that are consistently present. The largest one, measuring approximately 0.4 to 0.6 mm in diameter, provides the blood supply to a 25 x 15 cm cutaneous island. The incorporation of the proximal trunk of the thoracodorsal artery lengthens the pedicle, facilitating the anastomosis or the arc of rotation (in the case of island flaps) but does not increase the amount of tissue transferable. Five clinical cases were done with this technique without tissue necrosis or flap loss.

Gene expression of transforming growth factor beta-1 in rabbit zone II flexor tendon wound healing : Evidence for dual mechanisms of repair

&NA; 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. (Plast. Reconstr. Surg. 100: 937, 1997.)

Hyaluronan and wound healing: a new perspective

Hyaluronan has long been associated with the remodelling extracellular matrix. Such remodelling occurs in development, growth and wound healing. This role has been thought to be related to the physical structure and chemical composition of the pure glycosaminoglycan chain. We question this proposition and present evidence which suggests that proteins associated with hyaluronan may be more critical determinants of tissue remodelling.

Fetal wound healing : a biochemical study of scarless healing

Human fetal surgery is being successfully performed today in a small number of highly selected patients for conditions that may lead to irreversible damage to the fetus and threaten the viability of the newborn. Following surgical repair, fetal wounds heal without scarring. This study was initiated to characterize fetal wounds both histologically and biochemically. Gore-Tex tubing was implanted into the subcutaneous tissue of the back of fetal, newborn, and adult New Zealand white rabbits. Light microscopic examination of healed wounds revealed no evidence of scar formation. Electron microscopy demonstrated a striated fibrillar structure suggestive of collagen within the lumen of the Gore-Tex tubing implants. Amino acid analysis (sensitivity 40 pmol) confirmed the presence of hydroxylysine and hydroxyproline within the Gore-Tex wound chambers indicating the presence of collagen in fetal wounds. The small amount of collagen precluded the typing of the collagen using cyanogen bromide peptide analysis. The absence of scarring and the small amounts of detectable collagen suggest a high degree of reorganization of the connective tissues involved in repair. The fetal wound matrix is rich in hyaluronic acid. Topical hyaluronic acid has been associated experimentally with a reduced amount of scarring in postnatal wound healing. Hyaluronic acid extracted from human skin and scar tissue is associated with collagen and other proteins. We propose that a hyaluronic acid-collagen-protein complex may play a role in fetal wound healing.

Microsurgical correction of facial asymmetry in 60 consecutive cases.

&NA; 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. (Plast. Reconstr. Surg. 97: 354, 1996.)

Calreticulin Enhances Porcine Wound Repair by Diverse Biological Effects

Extracellular functions of the endoplasmic reticulum chaperone protein calreticulin (CRT) are emerging. Here we show novel roles for exogenous CRT in both cutaneous wound healing and diverse processes associated with repair. Compared with platelet-derived growth factor-BB-treated controls, topical application of CRT to porcine excisional wounds enhanced the rate of wound re-epithelialization. In both normal and steroid-impaired pigs, CRT increased granulation tissue formation. Immunohistochemical analyses of the wounds 5 and 10 days after injury revealed marked up-regulation of transforming growth factor-beta3 (a key regulator of wound healing), a threefold increase in macrophage influx, and an increase in the cellular proliferation of basal keratinocytes of the new epidermis and of cells of the neodermis. In vitro studies confirmed that CRT induced a greater than twofold increase in the cellular proliferation of primary human keratinocytes, fibroblasts, and microvascular endothelial cells (with 100 pg/ml, 100 ng/ml, and 1.0 pg/ml, respectively). Moreover, using a scratch plate assay, CRT maximally induced the cellular migration of keratinocytes and fibroblasts (with 10 pg/ml and 1 ng/ml, respectively). In addition, CRT induced concentration-dependent migration of keratinocytes, fibroblasts macrophages, and monocytes in chamber assays. These in vitro bioactivities provide mechanistic support for the positive biological effects of CRT observed on both the epidermis and dermis of wounds in vivo, underscoring a significant role for CRT in the repair of cutaneous wounds.

Microvascular free-flap correction of severe hemifacial atrophy.

Rombergs disease is a progressive hemifacial atrophy of unknown etiology. Microsurgical reconstruction, focusing on the correction of facial asymmetry and restoration of contour, has become the “gold standard.” We report our experience with 15 patients involving 16 free-tissue transfers with a minimum of 1 year of follow-up who were treated from July of 1989 to January of 1993. All patients were classified as having severe atrophy. There were 7 males and 8 females in the series. Distribution of disease was a coup de sabre type or segmental pattern in 6 patients, whereas 9 patients had a hemifacial distribution. Fourteen patients had unilateral disease (7 right and 7 left), and 1 patient had bilateral atrophy. The average age of onset of disease was 11.9 years. The average duration of atrophy was 6.7 years. No patientwas operated on with a quiescent interval of less than 2 years. Average age at operation was 28.7 years, with a range from 6 to 46 years. Follow-up ranged from 1 to 4.5 years. Two patients had facial hematomas as the only complication. No flaps were lost. Flap revisions consisting of minor contour corrections were performed in 10 patients. Limited recurrence of facial atrophy was seen in a single patient 2 years postoperatively. All patients rated their improvement as excellent. The deepithelialized extended parascapular flap with large fascial extensions of dorsal thoracic fascia is our procedure of choice. This fascia can be folded into variable thicknesses to correct subtle contour defects of the upper lip, medial canthus, eyelids, and ear that have reportedly been difficult to reconstruct. These extensions can be placed easily across the midline to interdigitate with normal tissues at the boundary of the facial deformity. As such, the transition from augmented areas of the face to uninvolved areas is natural in contour. (Plast. Reconstr. Surg. 96: 800, 1995.)

Microsurgical correction of facial contour in congenital craniofacial malformations: the marriage of hard and soft tissue.

&NA; 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.

MICROVASCULAR FREE-FLAP SALVAGE OF THE DIABETIC FOOT : A 5-YEAR EXPERIENCE

This study reviews 21 microvascular free flaps to the diabetic foot in 19 patients over a 65-month period. All flaps were either to the plantar surface of the foot or to cover exposed Achilles tendon. Twenty of the flaps survived. The operations required a long, costly hospitalization with frequent recipient- and donor-site complications. All patients eventually ambulated on their flaps. Five patients came to proximal amputation from 6 to 37 months after surgery. Only one amputation was for flap breakdown.