Faculty Bibliography

BACKGROUND: Management of severe traumatic lower extremity injuries remains a considerable challenge. Free tissue transfer is now a standard part of reconstruction for Gustilo IIIB and IIIC injuries. There is limited information on arterial injury patterns in this population. We undertook a review of our experience to gain insight on vascular injury patterns and surgical outcomes. STUDY DESIGN: A 26-year retrospective analysis was performed of all lower extremity Gustilo IIIB and IIIC injuries requiring microvascular reconstruction at New York University Medical Center. Patient demographics, Gustilo classification, angiographic findings (conventional/computed tomographic angiography/magnetic resonance angiography), recipient vessels, elapsed time from injury, flap choices, and outcomes were examined. RESULTS: Two hundred twenty-two free flaps on 191 patients were performed from September 1982 until March 2008. There were 151 males and 40 females ranging in age from 4 to 83 years (median age 33 years). Patients sustained either Gustilo IIIB (170 patients) or IIIC (21 patients) open fractures. One hundred fifty-four patients had angiograms (78.2% IIIB, 100% IIIC). Sixty-six (42.9%) had normal 3-vessel runoff and 88 (57.1%) were abnormal. Sixty-one patients (31.9%) had anterior tibial injuries, 17 patients (8.9%) had posterior tibial injuries, and 30 (15.7%) had peroneal injuries. Sixty-three complications occurred (11 early thrombosis, 33 requiring secondary procedures, and 10 requiring amputation). CONCLUSIONS: Angiography of severe lower extremity injuries requiring free flap reconstruction usually revealed arterial injury and is generally indicated. In our experience, the anterior tibial artery is most commonly injured and the posterior tibial artery is most likely to be spared and used as a recipient

BACKGROUND: Atypical claudication is a relatively uncommon problem within the general population. However, suspicion for the diagnosis is raised when young and athletic patients present with symptoms of claudication during exercise. The most common causes of atypical claudication are anatomical variants, including popliteal artery entrapment syndrome and tarsal tunnel syndrome. These variants result in impaired arterial flow and nerve compression, respectively. In this report, we present a seminal case of dorsalis pedis artery entrapment by the extensor hallucis brevis tendon during active dorsiflexion of the foot. METHODS: The patient was a 42-year-old male without significant past medical history, who presented with claudication in both feet upon active dorsiflexion. He underwent dynamic arterial duplex studies that first revealed normal flow in the neutral position and then revealed complete cessation of flow in both duplex and Doppler modes on dorsiflexion of the foot. He also underwent dynamic magnetic resonance angiography of bilateral lower extremities that revealed an incomplete pedal arch with early termination of the posterior tibial artery on static images and termination of the dorsalis pedis artery at notching on the dorsum of the foot during dorsiflexion. The patient was taken to the operating room for bilateral dorsalis pedis artery exploration. During exploration, the patient was found to have entrapment of the dorsalis pedis artery by the extensor hallucis brevis (EHB) tendon. This was documented by both direct visualization and intraoperative cessation of Doppler signal on dorsiflexion. Since the EHB tendon provides only secondary function to the extensor hallucis longus (EHL) tendon, the EHB was transected near its insertion and transposed directly to the EHL tendon. This allowed for normal extensor function of the great toe and restored triphasic Doppler signals during dorsiflexion. CONCLUSION: Dorsalis pedis arterial entrapment is a novel cause of atypical claudication. It is extremely uncommon as patients must have both abnormal anatomy and an incomplete pedal arch to display symptoms. Similar to other entrapment syndromes, if identified before permanent arterial scarring, the treatment does not require a bypass procedure. Removal of the tendon along with transposition will allow cessation of symptoms without impaired dorsiflexion of the great toe

BACKGROUND: Mobius syndrome is a disorder characterized by developmental impairment of cranial nerve VII, VI, often XII, and other cranial nerves. Facial reanimation in such patients restores the ability of some motion and of limited emotional expression. In one-fourth of these patients, hypoglossal involvement results in severe speech impairment due to tongue atrophy and lack of voluntary mobility. Bilabial incompetence due to facial paralysis further deteriorates speech capability. Direct tongue neurotization has been used by the senior author (J.K.T) to improve tongue function and speech intelligibility in patients with Mobius syndrome. This study presents the senior author's experience with the technique as a component of multistage facial reanimation procedures. METHODS: Data collection was performed by retrospective review on six patients with Mobius syndrome who underwent direct tongue neurotization. In addition, each patient was videotaped for 30 minutes preoperatively and postoperatively according to a standardized protocol. RESULTS: Four independent investigators scored speech intelligibility in each patient using a standardized grading system. The results showed considerable improvement in speech intelligibility and articulation. Higher improvement was noted in patients with partial bilateral hypoglossal involvement than in patients with complete unilateral involvement of the hypoglossal nerve, as well as in younger ages. No difference was noted between sexes. CONCLUSIONS: To the authors' knowledge, this is the first study presenting the effect of direct tongue neurotization on speech intelligibility in patients with Mobius syndrome. Tongue neurotization has therefore an important role in restoring the ability of these patients to communicate and obtain the potential to develop normal social skills

Calcium phosphate-based bioactive ceramics in various physical and chemical formulations have been extensively utilized as biomaterials for bone regeneration/conduction. However, the determination of their in vivo temporal behavior from the short to long term in humans has been a challenge due to the lack of physical reference for morphologic and morphometric evaluation. The present study evaluated bone morphology and morphometry (bone-to-implant contact [BIC]) around plasma-sprayed hydroxyapatite (PSHA)-coated endosseous implants that were retrieved due to prosthetic reasons while successfully in function at the posterior region of the jaws from as early as 2 months to approximately 13 years after a 6-month healing period after placement. Bone morphology was evaluated by light microscopy, and BIC was determined using computer software. Irrespective of the time in vivo, lamellar bone was observed in close contact with the implant PSHA-coated surface and between plateaus. BIC ranged from approximately 35-95%, was highly directional, and Haversian-like osteonic morphology between plateaus was observed for most implants. The PSHA coating was present with little variation in thickness between the samples retrieved regardless of time in vivo.

We previously reported that topically applied calreticulin (CRT), a calcium-binding ER chaperone protein comprising N, P, and C domains, markedly enhances diabetic murine (db/db) and porcine cutaneous wound healing. Consistent with the potent wound healing effects, we further showed, in vitro, that exogenous CRT stimulated proliferation of keratinocytes and fibroblasts, induced concentration-dependent migration of these cells and monocytes and macrophages, and upregulated protein expression of collagen, fibronectin, and TGF-beta-3 in fibroblasts. Notably, all these broad-ranging effects purport novel non-ER functions for CRT that act from outside the cell inward. The current studies address: 1) whether the ER chaperone function of CRT is required for its extracellular functions, 2) the molecular structure(s) of CRT that function in its biological activities and 3) the in vitro effects of CRT on diabetic compared to normal mouse and human fibroblasts. Using CRT null mouse embryo fibroblasts (K42) compared to wild type (K41) in proliferation and migration assays (scratch plate and chamber), we show that exogenous CRT stimulates proliferation of null K42 cells to a similar extent as K41 cells (2-fold at 10 pg/ml). However, K42 cells require 100 times more CRT for a peak migratory response (1 vs 100 ng/ml), with a 20% decreased response. We also show that the C domain stimulates fibroblast proliferation to the same extent and peak response as the entire molecule. Finally, we show that fibroblasts isolated from db/db mouse skin and human fibroblasts cultured in high glucose, to simulate type II diabetes, respond to CRT by migration and proliferation albeit with 1/3 less robust response requiring 10-fold more CRT for peak responses compared to controls. The breath of novel non-ER functions of CRT, structure-function relationships, and effects on diabetic cells in vitro underscore this molecule as a potential potent agent for the topical treatment for healing diabetic wounds