Douglas C. Ross

Beta-catenin expression in Dupuytren's disease: potential role for cell–matrix interactions in modulating beta-catenin levels in vivo and in vitro

Dupuytrens disease (DD) is a superficial fibromatosis of the hand. Although the molecular mechanisms responsible for this disease are unknown, recent studies suggest that beta-catenin may be a key factor involved in fibromatosis. In this study, we analysed the in vivo and in vitro expression levels of beta-catenin in DD, using surgical specimens and primary cell lines. Although no somatic mutations (exon 3) of beta-catenin were detected, Western blot analysis revealed high levels of beta-catenin in diseased palmar fascia, and low to undetectable levels of beta-catenin in patient-matched normal palmar fascia. Immunohistochemistry analysis showed high levels of beta-catenin expression within the disease fascia, as well as cytoplasmic and nuclear accumulations of the protein. Immunoprecipitation of beta-catenin from seven patient lesions showed the protein to be tyrosine phosphorylated. Lastly, Western analysis of three patient-matched (disease and normal fascia) primary cell cultures showed significantly elevated levels of beta-catenin in disease cells cultured in three-dimensional collagen lattices. This is the first extensive in vivo and in vitro characterization of beta-catenin in DD, and the first to suggest that the extracellular matrix may play an important role in modulating beta-catenin stability in DD.

A new, validated instrument to evaluate competency in microsurgery: the University of Western Ontario Microsurgical Skills Acquisition/Assessment instrument [outcomes article].

Background: The authors present a model for microsurgery learning as well as a validated instrument to evaluate microsurgical competency. Methods: Novice microsurgeons participated in three 3-hour sessions wherein they completed a number of increasingly complex, standardized microsurgical tasks. Performance was recorded and graded using a newly developed University of Western Ontario Microsurgery Skills Acquisition/Assessment (UWOMSA) instrument. The knot-tying and anastomosis modules contained three categories with five-point Likert scales. Each learners performance was assessed by two blinded surgeons. Reznicks validated global rating scale for operative performance was utilized to establish criterion validity. Within-scale scores were compared via intraclass correlation and between-scale scores with Pearson correlation coefficient. Linear regression was used to evaluate the effect of various predictors on UWOMSA scores. Results: Thirty-seven videos (9.6 hours) were reviewed, including 20 knot-tying sessions and 17 anastomoses. Interrater reliability of UWOMSA was high, with an intraclass correlation coefficient of 0.75 (0.57, 0.87). The intraclass correlation of the global rating scale was 0.79 (0.62, 0.89). Intrarater reliability of the UWOMSA was also high, with an intraclass correlation of 0.69 (0.48, 0.83). The intraclass correlation of the global rating scale was 0.69 (0.47, 0.84). Measures of criterion validity demonstrated strong agreement between UWOMSA and the global rating scale (Pearson correlation coefficient, 0.96; p < 0.001). Measures of construct validity demonstrated that higher scores on the UWOMSA were associated with faster knot tying (p < 0.0001) and higher postgraduate year level (p = 0.05). Conclusions: The UWOMSA instrument performed well in terms of reliability and validity. Further study is planned to assess the instruments ability to predict microsurgical skills translation to the clinical setting.

Elevated Levels of β-catenin and Fibronectin in Three-dimensional Collagen Cultures of Dupuytren's Disease Cells are Regulated by Tension in Vitro

BackgroundDupuytrens contracture or disease (DD) is a fibro-proliferative disease of the hand that results in the development of scar-like, collagen-rich disease cords within specific palmar fascia bands. Although the molecular pathology of DD is unknown, recent evidence suggests that β-catenin may play a role. In this study, collagen matrix cultures of primary disease fibroblasts show enhanced contraction and isometric tension-dependent changes in β-catenin and fibronectin levels.MethodsWestern blots of β-catenin and fibronectin levels were determined for control and disease primary cell cultures grown within stressed- and attached-collagen matrices. Collagen contraction was quantified, and immunocytochemistry analysis of filamentous actin performed.ResultsDisease cells exhibited enhanced collagen contraction activity compared to control cells. Alterations in isometric tension of collagen matrices triggered dramatic changes in β-catenin and fibronectin levels, including a transient increase in β-catenin levels within disease cells, while fibronectin levels steadily decreased to levels below those seen in normal cell cultures. In contrast, both fibronectin and β-catenin levels increased in attached collagen-matrix cultures of disease cells, while control cultures showed only increases in fibronectin levels. Immunocytochemistry analysis also revealed extensive filamentous actin networks in disease cells, and enhanced attachment and spreading of disease cell in collagen matrices.ConclusionThree-dimensional collagen matrix cultures of primary disease cell lines are more contractile and express a more extensive filamentous actin network than patient-matched control cultures. The elevated levels of β-catenin and Fn seen in collagen matrix cultures of disease fibroblasts can be regulated by changes in isometric tension.

Sensibility following innervated free TRAM flap for breast reconstruction.

Background: The free transverse rectus abdominis musculocutaneous (TRAM) flap has proven to be a reliable means of recreating the aesthetic breast form after mastectomy. The purpose of this study was to determine whether neurotization of the free TRAM flap improved sensation of the reconstructed breast. Methods: Twenty-seven patients undergoing 37 free TRAM flap reconstructions were randomized to receive either an innervated (12 patients, 18 breasts) or a noninnervated flap (15 patients, 19 breasts). A nerve repair between the T10 intercostal of the TRAM flap and the anterior sensory branch of the fourth intercostal nerve was performed for innervation. Sensory testing (Semmes-Weinstein monofilaments, hot-cold discrimination, two-point discrimination) was performed by one blinded examiner in a standardized pattern. Results: Mean follow-up was 16 months. Demographic analysis revealed no significant differences in patient age, height, smoking, radiation therapy, and nipple-areola reconstruction between patient groups (p > 0.3). Patients in the noninnervated group, however, were heavier (p = 0.03). Preoperative sensation was not significantly different in the noninnervated and innervated groups. Postoperative pressure threshold and temperature discrimination were significantly improved in the innervated flaps (p < 0.05). Noninnervated flaps displayed a pattern of increasing sensibility from the center toward the periphery while innervated flaps regained sensation throughout. Conclusions: Innervation of the free TRAM flap provides improved sensation to the reconstructed breast and is a simple adjunct to breast reconstruction.

Ultrasound-guided peripheral regional blockade in patients with Charcot-Marie-Tooth disease: a review of three cases.

Purpose: To describe the clinical presentation of three patients with Charcot-Marie-Tooth disease, who underwent uneventful upper limb surgery following successful peripheral nerve blockade, and to review the anesthetic implications in patients with Charcot-Marie-Tooth disease.Clinical features: In three patients with Charcot-Marie-Tooth disease presenting for surgery of the upper limb, the motor response, following nerve stimulation, was suboptimal. However, ultrasound guidance was effective in visualizing the needle-nerve interaction, and local anesthetic was injected around the nerves. Good block ensued and surgery proceeded in all patients without complications. No exacerbation of the neurological condition was observed in any patient.Conclusions: Charcot-Marie-Tooth disease is a demyelinating, hereditary, motor and sensory neuropathy characterized by abnormalities of nerve conduction. Regional anesthesia of the upper limb is feasible in these patients, and these cases show that ultrasound guidance makes peripheral nerve block possible in patients for whom traditional methods of nerve localization fail.RésuméObjectif: Décrire la présentation clinique de trois patients souffrant de la maladie de Charcot-Marie-Tooth subissant une chirurgie d’un membre supérieur sans complications à la suite la mise en place réussie d’un bloc des nerfs périphériques, et réitérer les implications anesthésiques chez les patients souffrant de la maladie de Charcot-Marie-Tooth.Éléments cliniques: Dans le cas de trois patients souffrant de la maladie de Charcot-Marie-Tooth se présentant pour une chirurgie d’un membre supérieur, la réaction motrice était sous-optimale après stimulation nerveuse. Cependant, l’échoguidage a permis de visualiser l’interaction entre l’aiguille et le nerf, et un anesthésique local a été injecté autour des nerfs. Ainsi, un bloc efficace a été réalisé et la chirurgie s’est déroulée sans complications chez les trois patients. Aucune exacerbation de l’état neurologique n’a été observée chez ces patients.Conclusions: La maladie de Charcot-Marie-Tooth est une neuropathie sensori-motrice héréditaire due à une démyélinisation et caractérisée par des anomalies au niveau de la conduction nerveuse. L’anesthésie régionale des membres supérieurs est réalisable chez les patients souffrant de cette maladie, et les cas présentés ici montrent que l’échoguidage permet une anesthésie des nerfs périphériques chez les patients chez lesquels les méthodes conventionnelles de localisation des nerfs échouent.

Sensibility following Innervated Free TRAM Flap for Breast Reconstruction: Part II. Innervation Improves Patient-Rated Quality of Life

Background: Restoring sensory innervation may be a useful adjunct in free flap head and neck reconstruction but, as yet, has not been shown to improve outcomes of breast reconstruction. The authors’ previous study demonstrated objectively improved sensation in a group of innervated transverse rectus abdominis musculocutaneous (TRAM) flap breast reconstruction patients relative to noninnervated flaps. This study compared patient-rated outcomes of free TRAM breast reconstruction in innervated versus noninnervated flaps. Methods: Twenty-seven women were randomized prospectively to undergo either innervated or noninnervated free TRAM flap breast reconstruction. For innervated flaps, the T10 intercostal nerve was harvested with the TRAM flap and neurotized to the T4 sensory nerve at the recipient site. Three validated outcome tools were administered after surgery: the Medical Outcomes Study 36-Item Short Form Health Survey, the Body Image after Breast Cancer Questionnaire, and the Functional Assessment of Cancer Therapy–Breast. Results were correlated with previously reported objective sensibility outcomes. Results: Eighteen of 27 women returned their questionnaires a mean 48 months after free TRAM flap reconstruction. Demographic analysis revealed no significant differences in patient age, height, smoking, radiation therapy, and nipple-areola complex reconstruction between randomized patient groups. There was a statistically significant improvement in all three measures in patients who were randomized to receive innervated free TRAM flaps compared with those receiving noninnervated flaps. Conclusion: This study demonstrates that innervation of free TRAM flaps used for breast reconstruction not only improves sensibility but also has a positive effect on patient-rated quality of life.

Swan Neck Deformity after Distal Interphalangeal Joint Flexion Contractures: A Biomechanical Analysis

The relationship between the flexor and extensor systems of the digits is both intricate and balanced, such that disruption of one system can affect the entire dynamics of the finger. The imbalance may be obvious, whereas the precipitating factor may be less obvious. These authors describe a case and provide a detailed biomechanical analysis of how a flexion contracture of the distal interphalangeal joint led to a swan neck deformity in one of their patients.

Nerve transfers and neurotization in peripheral nerve injury, from surgery to rehabilitation

Peripheral nerve injury (PNI) and recent advances in nerve reconstruction (such as neurotization with nerve transfers) have improved outcomes for patients suffering peripheral nerve trauma. The purpose of this paper is to bridge the gap between the electromyographer/clinical neurophysiologist and the peripheral nerve surgeon. Whereas the preceding literature focuses on either the basic science behind nerve injury and reconstruction, or the surgical options and algorithms, this paper demonstrates how electromyography is not just a ‘decision tool’ when deciding whether to operate but is also essential to all phases of PNI management including surgery and rehabilitation. The recent advances in the reconstruction and rehabilitation of PNI is demonstrated using case examples to assist the electromyographer to understand modern surgical techniques and the unique demands they ask from electrodiagnostic testing.

Long-term limb allograft survival using a short course of anti-CD45RB monoclonal antibody, LF 15-0195, and rapamycin in a mouse model.

Background. The purpose of this study was to determine if a short course of monoclonal antibody (mAb) against CD45RB, LF 15-0195, and rapamycin would achieve long-term survival by inducing tolerance in a mouse limb transplant model. Methods. Group 1 (n=9) consisted of nine isogenic (C57BL/6) transplants. Group 2 (n=3) included C57BL/6-to-BALB/c transplants receiving no drug therapy. Group 3 mice (n=4) were treated with mAb (3 mg/kg) and LF (2 mg/kg), and Group 4 (n=13) was treated with mAb, LF, and rapamycin (2 mg/kg). Both treatment groups received drug treatment for only 14 days posttransplantation. Animals were sacrificed if they displayed evidence of rejection or when deemed to be tolerant (defined as >day 100). Results. All isografts had normal histology and graft function on day 100. Untreated C57BL/6-to-BALB/c allografts developed acute rejection within 10 days. The combination of mAb and LF prolonged allograft survival to a mean of 39±7 days. In Group 4, two animals had to be sacrificed at days 28 and 76 due to acute urinary retention. Transplant tolerance was achieved in 8 of the remaining 11 animals with a mean survival time of 100±12 days. Donor specific tolerance was demonstrated through permanent acceptance of skin grafts from the donor strain and rejection of skin grafts from C3H mice. Three Group 4 animals showed clinical and histological signs of mild, chronic rejection. Dendritic cells isolated from tolerant recipients exerted a suppressive effect in mixed lymphocyte reaction. Conclusion. A short course of anti-CD45RB mAb and LF 15-0195 prolonged limb allograft survival. The addition of rapamycin induced limb allograft tolerance which is associated with the generation of tolerogenic dendritic cells that suppressed T-cell proliferation.

Refining perforator selection for DIEP breast reconstruction using transit time flow volume measurements.

Transit time flow volume has been used in cardiac surgery to assess small vessel flow characteristics. This study examines the usefulness of transit time flow volume (TTFV) in assessing perforator vessels in deep inferior epigastric artery perforator (DIEP) flap harvesting. The purpose of this study was to evaluate the correlation among computed tomographic angiography (CTA), intraoperative TTFV measurements, and hand-held Doppler signals in identifying perforators. Ten consecutive free DIEP breast reconstructions were prospectively evaluated using CTA to identify abdominal wall perforators. Intraoperatively, perforating vessels >1 mm in diameter were evaluated with a conventional hand-held 8-MHz Doppler and a TTFV measurement device. Vessel location was correlated with preoperative CTA . Waveform patterns and TTFV measurements were recorded for each vessel and correlated with both CTA and hand-held Doppler signals. Of the 54 perforators identified, TTFV showed arterial flow waveforms in 15 of 16 perforators identified by CTA and in 2 of the remaining 38 vessels. The sensitivity and specificity of TTFV in identifying arterial perforators were 94 and 95%, respectively. In contradistinction, hand-held Doppler was misleading in 70% of vessels. TTFV distinguishes arterial from venous waveforms in vessels that appear arterial by hand-held Doppler signals. CTA and TTFV are highly correlated, and the use of TTFV may prevent poor perfusion seen in some DIEP flaps.