Biomedical subjects

Hani S Matloub

Publications and source records attributed to Hani S Matloub.

At least 19 recordsLinked to original sources

PubMed2006

Sonographic differentiation of digital tendon rupture from adhesive scarring after primary surgical repair.

PURPOSE: After the surgical repair of finger tendons finger range of motion may be limited by tendon rupture or adhesive scarring. Differentiating tendon rupture from adhesive scarring may be difficult clinically. Digital tendon sonography allows the evaluation of tendon integrity in a dynamic setting. Our objective was to determine if sonography could differentiate tendon rupture from adhesive scarring in patients who have had primary tendon repair. METHODS: A retrospective review was performed of the radiographic, clinical, and surgical records of patients referred for finger sonography over a 2-year period. Twenty-eight digits in 21 patients were evaluated for finger tendon disruption after primary surgical repair. The diagnosis of complete tendon rupture was made when 1 or more of the following was identified: a gap separating the proximal and distal tendon margins, visualization of only the proximal tendon margin, or visualization of only the distal tendon margin. Adhesive scarring was diagnosed if the tendon appeared intact with abnormal peritendinous soft tissue abutting or partially encasing the tendon, with synovial sheath thickening, or with restricted tendon motion during dynamic evaluation. RESULTS: Sonography correctly identified tendon rupture or adhesive scarring in 27 of 28 digits with 1 false-positive case (sensitivity, 100%; specificity, 93%; positive-predictive value, 93%; negative-predictive value, 100%; accuracy, 96%). CONCLUSIONS: Sonography is an accurate modality for differentiating tendon rupture from adhesive scarring in patients with prior surgical tendon repair. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic, Level I.

Adolescent↗

PubMed2006

Engineering a composite neotrachea in a rat model.

BACKGROUND: Attempts to reconstruct the trachea have been largely unsuccessful because of its rigidity and opening to the outside environment. Materials that impart rigidity are usually alloplastic, so they cannot be exposed to the open environment without an unacceptably high risk of infection and rejection. The authors hypothesized that tissue engineering principles can be employed to construct a well-integrated neotrachea with rigid support and an epithelial lining to mimic the structure and function of the native trachea. METHODS: A 30-mm-long segment of polytetrafluoroethylene vascular graft with a diameter of 10 mm was lined with a fascial flap based on the superficial inferior epigastric artery with full-thickness skin grafts on its luminal surface. The composite unit was then buried under the abdominal skin of 20 rats and harvested 3 weeks later. Microfil and methylene blue dye were injected into the superficial inferior epigastric arteries and histologic analyses were performed to assess microcirculation and polytetrafluoroethylene-tissue integration. RESULTS: Two composite neotracheas experienced minor damage due to chewing by the rats, but all other neotracheas were viable and without infection. Injection studies demonstrated excellent circulation throughout the fascial flaps and skin grafts and across the polytetrafluoroethylene grafts to the overlying abdominal skin. Histologic analyses revealed abundant muscle-walled blood vessel ingrowth within the polytetrafluoroethylene grafts and all layers of the neotracheas with minimal inflammatory reactions. CONCLUSION: The authors successfully have engineered a well-integrated neotrachea in rats that possesses rigid support, an epithelial lining, and reliable coverage-the prerequisites for successful trachea reconstruction.

Animals↗

PubMed2005

Evidence for frequency-dependent arterial damage in vibrated rat tails.

The effects of single 4-hr bouts of continuous 30, 60, 120, and 800 Hz tail vibration (49 m/sec2, root mean squared) were compared to assess frequency-amplitude-related structural damage of the ventral caudal artery. Amplitudes were 3.9, 0.98, 0.24, and 0.0055 mm, respectively. Vibrated, sham-vibrated, and normal arteries were processed for light and electron microscopy. The Curry rat tail model of hand-arm vibration (Curry et al. Muscle Nerve 2002;25:527-534) proved well-suited for testing multiple frequencies. NFATc3 immunostaining, an early marker of cell damage, increased in smooth muscle and endothelial cells after 30, 60, and 120 Hz but not 800 Hz. Increased vacuolization, which is indicative of smooth muscle contraction, occurred for all frequencies except 800 Hz. Vacuoles increased in both endothelial and smooth muscle cells after 60 and 120 Hz. Only 30 Hz showed pronounced smooth muscle cell vacuolization along the internal and external elastic membranes, suggesting stretch-mediated contraction from the large amplitude shear stress. Discontinuities in toluidine blue staining of the internal elastic membrane (IEM) increased for all frequencies, indicating vibration-induced structural weakening of this structure. Patches of missing IEM and overlying endothelium occurred in approximately 5% of arteries after 60, 120, and 800 Hz. The pattern of damage after 800 Hz suggests that the IEM is disrupted because it resonates at this frequency. Vibration acceleration stress and smooth muscle contraction appear to be the major contributors to arterial damage. The pattern of vibration-induced arterial damage of smooth muscle and endothelial cells is frequency-amplitude-dependent.

Animals↗

PubMed2005

Neuropathological changes in vibration injury: an experimental study.

Vibration syndrome, a clinical condition arising from chronic use of vibrating tools, is associated with a spectrum of neurovascular symptoms. To date, only its vascular pathology has been extensively studied; we sought to determine what direct neurologic injury, if any, is caused by vibration. Hindlimbs of anesthetized rats were affixed to a vibrating platform 4 h a day for 7 days. Study animals were vibrated with set parameters for frequency, acceleration, velocity, and amplitude; control animals were not vibrated. On day 7, nerves were studied by light and electron microscopy. While light microscopy showed minimal histologic differences between vibrated (n=12) and control (n=12) nerves, electron microscopic changes were dramatic. Splitting of the myelin sheath and axonal damage (e.g., myelin balls and "finger ring") were consistently seen in both myelinated and nonmyelinated axons. Despite relatively short vibration, definite pathology was demonstrated, suggesting that vibration syndrome has a direct neurologic component.

Animals↗

PubMed2005

Vibration-induced disruption of retrograde axoplasmic transport in peripheral nerve.

Hand-arm vibration syndrome (HAVS) results from excessive exposure to hand-transmitted vibration. Whether the peripheral nerve damage characteristic of HAVS is a direct result of vibration or is secondary to vascular insufficiency remains unclear. The purpose of this study was to explore the effect of vibration exposure on axoplasmic transport in peripheral nerves and soleus motor neurons. Sciatic nerves and motor neurons from rats following two 5-h periods of vibration exposure demonstrated disruption in retrograde transport compared to normal. After 10 days of vibration (5 h/day), axoplasmic transport failed to recover within 24-48 h in most rats. This study demonstrates that disrupted axoplasmic transport is an early consequence of short-term vibration exposure. The effects of vibration on axoplasmic transport also appear to be cumulative. This study provides a new biological way to evaluate measures to prevent early vibration injury.

Animals↗

PubMed2005

Nifedipine pretreatment reduces vibration-induced vascular damage.

A rat-tail vibration model of hand-arm vibration was employed to test whether preemptive administration of nifedipine (5 mg/kg) to block vasoconstriction prevents vibration-induced arterial damage. The tails of vibrated and nifedipine-pretreated vibrated Sprague-Dawley rats were exposed continuously to 4 h of 60-HZ vibration at 49 m/s(2) rms. In nonvibrated anesthetized rats, the ventral tail arteries were bathed for 15 min in situ in 1 mM epinephrine or 1 mM norepinephrine to induce structural changes indicative of intense vasoconstriction. Arteries were processed for light and electron microscopy 45 min after treatment. Compared to sham control, 4-h vibration significantly (P < 0.01) reduced lumen size, generated endothelial disruption (7.0 +/- 2.6%), elevated nuclear factor of activated T cells c3 (NFATc3) expression in endothelial and smooth muscle cells, and increased smooth muscle cell vacuolization. The findings demonstrate that blockage of vibration-induced vasoconstriction with nifedipine prevents acute vascular damage. Smooth muscle and endothelial cells structurally altered by vasoconstriction are rendered susceptible to damage by vibration.

Animals↗

PubMed2005

Functional improvement with digital prosthesis use after multiple digit amputations.

PURPOSE: Patients who sustain traumatic amputation of multiple fingers suffer both a functional and psychologic loss. Previous studies of prosthesis use for finger amputees have focused primarily on the psychologic benefits. Clinically our group noticed a functional improvement on hand function tests when patients with multiple digit amputations used a prosthesis. Given the expense of multiple finger prostheses we sought to determine if they led to a consistent functional improvement in these patients. METHODS: Ten consecutive patients performed a battery of hand function tests and rated their ability to perform a variety of activities of daily living both with and without their prosthesis using the Disabilities of the Arm, Shoulder, and Hand questionnaire. RESULTS: Our results show a significant improvement in 3-finger-pinch strength and grip strength and a trend of improvement of tip-pinch, lateral-pinch, and grip strength in dynamometer positions 1, 2, 3, and 4 in these patients when tested with and without their prostheses. Function in activities of daily living, as assessed by the Disabilities of the Arm, Shoulder, and Hand questionnaire, was improved globally with prosthesis use. In addition, significant improvement was noted in several specific activities including opening a jar, writing, and turning a key, among others. CONCLUSIONS: These results show that prosthesis use provides a functional benefit to these patients in multiple activities.

Activities of Daily Living↗

PubMed2005

Intraneural perineurioma of the radial nerve in a child.

An intraneural perineurioma is an uncommon solitary neoplasm of major nerve trunks composed of perineurial cells from the peripheral nerve sheath. The typical course of intraneural perineurioma is indolent, with gradual-onset motor loss and presentation for evaluation months to years after onset of symptoms. We report a 9-year-old girl with an intraneural perineurioma of the radial nerve. Diagnosis was confirmed by histology and immunohistochemistry. Resection and nerve graft reconstruction were performed to prevent progression of motor compromise and to allow recovery of motor function. An algorithm for the management of focal intraneural tumors is shown.

Child↗

PubMed2005

Cortical adaptation to restoration of smiling after free muscle transfer innervated by the nerve to the masseter.

BACKGROUND: The child with Möbius syndrome presenting for facial reanimation presents a difficult challenge. When bilateral paralysis and paresis preclude use of the contralateral facial nerve, the authors' preferred donor nerve for reinnervation of free muscle transfer is a branch of the trigeminal nerve, the ipsilateral nerve to the masseter. METHODS: The authors have used a branch of the trigeminal nerve as a donor for three children with Möbius syndrome. RESULTS: Of three children with Möbius syndrome, two are now able to smile independently of jaw closure. One child is now 2.6 years past bilateral free gracilis transfers completed at age 13.2 years. The second child is 8.2 years past free gracilis transfer to the left side of the face performed at age 7.6 years. The third child is 5.6 years past bilateral facial reanimation with free latissimus and free gracilis flaps completed at age 13.4 years. This child is not able to smile independently of jaw closure. The two who are able to smile independently of jaw closure demonstrated maximum excursion of the lateral commissure on the affected sides when asked to smile without biting; however, they demonstrated minimal excursion of the lateral commissure on the affected sides when asked to bite without trying to smile. CONCLUSIONS: These findings indicate that smiling independently of jaw closure is attainable with reanimation to the masseteric branch, refuting previous speculations. Early age at operation and absence of complete bilateral paralysis in these two children may have contributed to cortical adaptation to smiling.

Adaptation, Physiological↗

PubMed2005

Serratus anterior in vivo contractile force study.

BACKGROUND: A major limitation of functional muscle transfer for facial and intrinsic hand reanimation is the inability to predict the force that will be generated by the transplanted muscle. METHODS: The authors studied the contractile force of the slips of the serratus anterior in situ in 10 patients and tested the gracilis muscle in four subjects as a control. RESULTS: Mean contractile force generated by each serratus slip was 0.178 pound (range, 0.019 to 0.797 pound). This compares favorably with the maximum force generated by smiling (0.307 pound). Muscle strength correlated strongly with age (r = -0.805, p = 0.005). The lowest slip generated less force than those above it (0.133 pound versus 0.191 pound); this difference did not reach statistical significance. When the strength of the lowest slip is compared with the more superior slips as a percentage of total force generated by the slips (to compensate for the effect of age on muscle strength), the lowest slip was significantly weaker (18.6 percent of total force versus 25.5 percent of total force, p = 0.013). Mean contractile force generated by the gracilis was 0.963 pound, significantly different from that generated by a serratus anterior slip (p = 0.009). CONCLUSIONS: Each serratus slip could potentially be used to generate a separate force vector for facial reanimation. Further separation of the flap along preexisting fascial planes may allow generation of up to 10 independent force vectors, making the serratus anterior muscle flap an attractive option for facial reanimation and possibly intrinsic hand muscle reconstruction.

Adolescent↗

PubMed2004

Irrigation pressure and vessel injury during microsurgery: a qualitative study.

Irrigation solution is routinely used in microsurgery. While the anticoagulation solution may aid in anastomotic patency, the direct effect of pressure irrigation can have a detrimental effect on the vessel. An experimental study was performed to determine the effect of irrigation pressure on the vessel wall. Histological evaluation with hematoxylin and eosin (H&E) stain and scanning electron microscopy (SEM) was performed on the arteries of New Zealand white rabbits irrigated with lactated Ringer's solution at pressures of 80 mmHg, 100 mmHg, and 500 mmHg. H&E staining and SEM microscopy demonstrated injury to the endothelial cells and internal elastic lamina at pressures of 100 mmHg or greater. Controlling microsurgical irrigation pressure to less than 100 mmHg may help to avoid vessel injury.

Animals↗

PubMed2004

Ultrastructural analysis of peripheral-nerve regeneration within a nerve conduit.

The purpose of this study was to observe the cellular components of regenerating peripheral nerves within a nerve conduit. Rat sciatic nerves were placed in a silicone conduit with a 5-mm gap between nerve endings. At weekly intervals for 6 weeks, 70-nm sections of nerve tissue from the conduit were obtained for ultrastructural observation. The principal cellular components by the end of the first week were macrophages and fibroblasts. By the end of the second week, both myelinated and unmyelinated nerve fibers began to pass through the entire conduit. By the end of the fifth week, nerve fibers were present at various levels of maturity, with no evidence of inflammatory or immunologic response. By the end of the sixth week, the percentage of nerve fibers was 86 percent of the cellular components. This analysis provides cellular data on which to base additional research regarding functional outcomes when using nerve conduits.

Animals↗

PubMed2004

Detailed neurovascular anatomy of the serratus anterior muscle: implications for a functional muscle flap with multiple independent force vectors.

A functional muscle free flap with multiple muscle segments that could be oriented independently to produce different force vectors would be beneficial in facial reanimation and upper extremity reconstruction. The serratus anterior muscle has this potential because two or more individual muscle slips can be transferred on a single vascular pedicle. Although serratus anterior muscular anatomy has been studied previously, little attention has been given to the intramuscular anatomy. Muscle slips 5 through 9 (and 10, if present) in 50 specimens from 27 cadavers were studied following intraarterial latex injection. Eight specimens were injected with a radiopaque material (latex/diatrizoate/lead mixture) for x-ray delineation of the intramuscular vascular pattern. Slips 5 through 9 are consistently supplied by a single dominant branch of the thoracodorsal artery and innervated by the long thoracic nerve. Dissection revealed that the long thoracic nerve and its branches invariably follow the artery and divide proximal to the corresponding arterial division. There is a consistent vascular pattern to each muscle slip, in which the serratus artery gives rise to common slip arteries, each of which supplies adjacent muscle slips. The mean length of a muscle slip from its origin on the rib periosteum to the division of the common slip artery is 9.6 cm. These findings imply that the slips may be separated to the level of these common slip arteries, with up to five slips transferred on a single neurovascular pedicle and each slip oriented independently to provide multiple muscle force vectors. With these possibilities, the reconstructive surgeon may be able to restore more natural facial animation and better intrinsic muscle function in the upper extremity.

Adolescent↗

PubMed2003

Osteogenesis in calvarial defects: contribution of the dura, the pericranium, and the surrounding bone in adult versus infant animals.

Guided bone regeneration is a promising means for reconstructing bone defects in the cranium. The present study was performed to better define those factors that affect osteogenesis in the cranium. The authors studied a single animal model, investigating the contribution of the dura, the pericranium, and the adjacent calvarial bone in the process of calvarial regeneration in both mature and immature animals. Bilateral, 100-mm2, parietal calvariectomies were performed in immature (n = 16) and mature (n = 16) rabbits. Parietal defects were randomized to one of four groups depending on the differential blockade of the dura and/or the pericranium by expanded polytetrafluoroethylene membranes. Animals were humanely killed after 12 weeks, and histometric analysis was performed to quantitate the area of the original bone defect, new bone formation, and new bone density. Bone formation was quantified separately both at the periphery and in the center of the defects. Extrasite bone formation was also quantified both on the dural and on the pericranial sides of the barriers. Bone regeneration was incomplete in all groups over the 12-week study period, indicating that complete bone healing was not observed in any group. The dura was more osteogenic than the pericranium in mature and immature animals, as there was significantly more extrasite bone formed on the dural side in the double expanded polytetrafluoroethylene barrier groups. In both the dural and the double expanded polytetrafluoroethylene barrier groups, dural bone production was significantly greater in immature compared with mature animals. The dura appeared to be the source of central new bone, because dural blockade in the dural and double expanded polytetrafluoroethylene groups resulted in a significant decrease in central bone density in both mature and immature animals. Paradoxically, isolation of the pericranium in mature animals resulted in a significant reduction in total new bone area, whereas pericranial contact appeared to enhance peripheral new bone formation, with the control group having the greatest total new bone area. The present study establishes a model to quantitatively study the process of bone regeneration in calvarial defects and highlights differences in the contribution of the dura and pericranium to calvarial bone regeneration between infant and adult animals. On the basis of these findings, the authors propose that subsequent studies in which permeability of the expanded polytetrafluoroethylene membranes is altered to permit migration of osteoinductive proteins into the defect while blocking prolapse of adjacent soft tissues may help to make guided bone regeneration a realistic alternative for the repair of cranial defects.

Aging↗

PubMed2002

Vibration injury damages arterial endothelial cells.

Prolonged exposure to hand-transmitted vibration can cause debilitating neural and vascular dysfunction in humans. It is unclear whether the pathophysiology involves simultaneous or sequential injury of arteries and nerves. The mechanism of vibration injury was investigated in a rat tail model, containing arteries and nerves structurally similar to those in the human hand. Tails were selectively vibrated for 1 or 9 days with the remainder of the animal at rest. One vibration bout of 4 h/day, 60 HZ, 5 g (49 m/s(2)) acceleration, injured endothelial cells. Injury was signaled by elevated immunostaining for NFATc3 transcription factor. Electron microscopy revealed that vibration for 9 days produced loss and thinning of endothelial cells, with activated platelets coating the exposed subendothelial tissue. Endothelial cells and arterial smooth muscle cells contained double membrane-limited, swollen processes indicative of vasoconstriction-induced damage. Laser doppler surface recording demonstrated that 5 min of vibration significantly diminished tissue blood perfusion. These findings indicate that early injury involves vasoconstriction and denuding of the arterial endothelium.

Animals↗

PubMed2002

A modified end-to-side method for peripheral nerve repair: large epineurial window helicoid technique versus small epineurial window standard end-to-side technique.

This study evaluated 2 end-to-side nerve repair techniques for ability to induce nerve sprouting and muscular recovery. Twenty-four rats underwent identical surgeries. The helicoid method of neurorrhaphy was used on the left (large epineurial window) side and the standard end-to-side (small epineurial window) repair on the right side of each rat to repair the peroneal nerve. The helicoid configuration markedly increases the area from which axons can sprout into the recipient nerve. At 11 months after surgery, axons were counted in donor and recipient nerves, and muscle moist weight of the extensor digitorum longus (EDL) and tetanic force were measured. Muscle volume, tetanic force, and moist weight of EDL muscles were significantly higher on the left side (helicoid) than on the right (end-to-side). Histologic analysis and nerve axon counting of the recipient peroneal nerve showed significantly more regenerative nerves on the left than on the right. There were no significant differences between sites above and below the repair site in the donor tibial nerve in regard to mean number of nerve fibers. Helicoid nerve repair can entice more nerve fiber sprouts from the intact donor nerve, improve muscular recovery, and maintain donor nerve health.

Anastomosis, Surgical↗

PubMed2002

Nerve repair at different angles of attachment: experiment in rats.

Sixteen rats underwent two procedures to test the efficacy of oblique vs. transverse nerve repair. On the left, the peroneal nerve was transected at an oblique angle (30-degree) with subsequent oblique end-to-end repair performed. On the right, the peroneal nerve was transected at a transverse angle (90-degree) with subsequent end-to-end repair. At 3.5 months postoperatively, the moist muscle weight of the extensor digitorum longus (EDL) and tetanic force were measured, and axons were counted in donor and recipient nerves. Muscle volume, tetanic force, and moist weight of EDL muscles were statistically significantly higher on the left side (oblique) than on the right (transverse). Histologic analysis with nerve axon counting of the recipient peroneal nerve revealed significantly more regenerated nerve fibers on the left than on the right. The authors concluded that oblique nerve repair enhances nerve-fiber sprouting from the proximal donor nerve by increasing the coapted surface area, thus improving muscle recovery.

Animals↗

PubMed2002

Anterolateral thigh fasciocutaneous island flaps in perineoscrotal reconstruction.

This study presents the authors' experience using the anterolateral thigh fasciocutaneous flap for complex perineal and scrotal reconstruction. Anterolateral thigh fasciocutaneous island flaps were performed in seven patients between January and June of 2000 (six male, one female; mean age, 52 years; age range, 9 to 72 years). Four of the seven patients had scrotal or perineal defects after multiple debridements for Fournier's gangrene. Two of these four had exposed testicles. Three flaps were used for recurrent ischial ulcers. A true septocutaneous perforator (type 1) running between the rectus femoris and the vastus lateralis muscles was found in only two patients. In four patients, the cutaneous perforators were found to be intramuscular, originating from the descending branch (type 2). In the other patient, the musculocutaneous perforator originated from the lateral circumflex femoris artery independently (type 3). In these cases, intramuscular dissections were performed to follow each perforator to its main trunk. Mean follow-up was 8 months (range, 5 to 10 months), and all flaps survived. Three patients developed minor wound dehiscence in the posterior aspect of the perineal wound because of fecal contamination and skin maceration. Both wounds healed secondarily. Scrotal reconstruction with the anterolateral thigh flap gave an excellent aesthetic result. The authors conclude that the anterolateral thigh flap is a reliable flap for perineoscrotal reconstruction.

Adolescent↗