Faculty Bibliography

We describe two modified methods for median-to-ulnar motor conduction comparison in the diagnosis of median neuropathy at the wrist: the median-thenar to ulnar-thenar latency difference (TTLD), and the median-thenar to ulnar-hypothenar latency difference (THLD). We also describe an F-wave ulnar-to-median comparative test, the F-wave latency difference (FWLD). The abnormal cutoffs based upon 34 normal controls are: TTLD, 0.8 ms; THLD, 1.2 ms; FWLD, 0.6 ms. In 50 patients (79 hands) with clinically defined carpal tunnel syndrome and electrophysiological evidence of median neuropathy at the wrist (based upon a prolonged median nerve palm-wrist latency), the diagnostic sensitivities were: 95-98%, 85-88%, and 75-78%, respectively. These tests are therefore highly sensitive. They are easily performed and require minimal additional effort to incorporate into commonly used clinical electrodiagnostic routines. They may be advantageous when a concomitant polyneuropathy is present, and they may also help avoid technical pitfalls and aid in identification of anatomic variants

Among the pathological sequelae of facial paralysis is a paralytic eye. Apart from the psychological and aesthetic deficits, facial paralysis if left untreated can lead to dryness, ulceration and eventual blindness. Although numerous restorative microsurgical approaches have been introduced to address the sequelae of this problem, complete restoration of function to denervated facial muscles remains elusive.Utilizing the rat model of facial paralysis the present research has as an objective to examine a dual treatment approach. Specifically, this study combined the current microsurgical treatment of the cross-facial nerve graft with local administration of insulin-like growth factor I (IGF-I).The efficacy of this combined approach (cross-facial nerve graft + IGF-I) was assessed in the following ways: (a) behavior measurement of the blink response and (b) histomorphometry light and electron microscopy of the entire nerve graft. These data will help provide insight into the restoration of facial muscle function after trauma and assist in the future development of more potent treatment strategies.7he local adnunistration of IGF-I (50 micro g/ml) to the cross-facial nerve graft was found to restore the blink response faster and to strengthen the degree of eye closure. Light microscopy examination revealed that IGF-I significantly enhanced axonal regeneration within a nerve graft (a 22% increase in the mean number of axons), and increased the mean nerve fiber diameter and myelin thickness. Electron microscopy assessment of the nerve grafts demonstrated that the IGF-I treated grafts possessed a greater density of microtubules, which were evenly distributed within the axoplasm

OBPP is a disease with deleterious medical, psychological, and socioeconomic sequelae for the patient and his or her family. The majority of patients show acceptable spontaneous recovery with nonoperative management, which includes aggressive physical rehabilitation and electrical stimulation. There are patients with guarded prognosis, however, who have no chance of recovery unless they undergo early aggressive surgical reconstruction of the injured brachial plexus. It is of great importance to diagnose the injury type as early as possible, especially if there is minimal recovery in the early weeks of follow-up. This allows timely reconstruction to take place, earlier than 3 months for global palsy cases and at 3 months in Erb's type lesions, for best functional results

Thus far, devastating injuries of the adult brachial plexus have had a poor prognosis. This article presents the possible outcomes of aggressive microsurgical reconstruction in the largest series of patients in North America to date. It should change the pessimistic outlook that has surrounded these lesions. In this study, the outcomes of surgery were analyzed in relation to the type and level of injury, the age of the patient, and the denervation time; stronger donors for neurotization in relation to the various targets were delineated. The results were analyzed in 204 patients with adequate follow-up from a total of 263 patients who were operated on between 1978 and 1996. The mean age of the patients was 25.9 years, and the injuries were caused by high-velocity motor accidents involving avulsion in 55 percent of the patients. Nerve reconstruction included 577 nerve repairs (140 direct neurotizations and 437 cases of nerve grafting). Microneurolysis was performed in 89 cases. Vascularized nerve grafts were used in 120 repairs. Muscle transfers (29 pedicled and 78 free) were used to enhance function. The results were good or excellent in 75 percent of suprascapular nerve reconstructions, 40 percent of deltoid reconstructions, 48 percent of biceps reconstructions, 30 percent of triceps reconstructions, 35 percent of finger-flexion reconstructions, and 15 percent of finger-extension reconstructions. The majority of the patients had protective sensation and pain relief postoperatively

This research group has introduced a model of end-to-side neurorrhaphy, in which reinnervation occurs without frank damage to donor axons. The current study used in situ hybridization to test the hypothesis that insulin-like growth factor (IGF-I and IGF-II) mRNA levels increase at the coaptation site and grafted nerve following end-to-side repair, and that this increase is associated with axonal sprouting and growth. One week after end-to-side coaptation, IGF-I mRNA was localized predominantly on the epineurial side of the graft perineurium, while IGF-II was seen mainly on the endoneurial side. IGF-I hybridization was greatest at this time and declined by 2 weeks post-procedure. No changes in IGF mRNA levels occurred in the distal donor nerve. The increase in IGF-I mRNA at 1 week preceded the appearance of myelinated axons. The presence of myelinated axons within the graft 2 weeks after end-to-side coaptation was associated with a decline in IGF-I mRNA. These data are the first to demonstrate increased IGF mRNA levels associated with axonal sprouting and growth following end-to-side neurorrhaphy. Moreover, the findings support those of earlier studies by others implicating IGFs in axonal regeneration. The increase in IGF mRNA during sprouting and axonal growth into an end-to-side coaptation indicates that the local therapeutic augmentation of endogenous IGF levels at the coaptation site may enhance axonal sprouting from a minimally injured donor nerve, and thereby increase the number of axons that reinnervate the graft

Insulin-like growth factor-II (IGF-II) has been shown to increase the rate of axon regeneration in a number of models involving the rat sciatic nerve. This project studied the effects of IGF-II on an end-to-side nerve repair. In this study, the musculocutaneous nerve of a Sprague-Dawley rat was transected and coapted by end-to-side neurorrhaphy to the median nerve. Experimental animals received a local infusion of IGF-II at the repair site, while control animals received a local infusion of placebo solution. This new model allowed for the assessment of functional outcome through the Terzis grooming test. The use of an end-to-side repair minimized potential damage to the motor nerve donor (median nerve) and encouraged lateral axon sprouting into the severed nerve (musculocutaneous nerve). Histologic results showed that the IGF-II treated group had higher axon counts and greater myelin thickness in the reinnervated musculocutaneous nerve. IGF-II-treated animals also had significantly greater motor-end-plate counts in the biceps muscle. Furthermore, the IGF-II group scored consistently higher in the grooming test, compared to the control group

The optimal period of time between peripheral-nerve repair and initiation of limb lengthening procedures has never been precisely determined. In the clinical setting, the surgeon must decide how long the repaired nerves should be allowed to heal before subjecting them to the forces created by the limb-lengthening process. The authors designed a study to quantify and qualify the effects of different recovery periods between initial nerve repair and subsequent limb-lengthening via distraction osteogenesis. Forty-two Sprague-Dawley male rats were randomized in two different categories of nerve repair: end-to-end and nerve grafts. At 4, 8 and 12 weeks after nerve reconstruction, the femur was submitted to limb-lengthening at a rate of 1 mm/day (0.25 mm every 6 hr). Sciatic Function Index (SFI) evaluation indicated that the impact of distraction was detrimental in the grafted nerves, although they maintained their electrical and morphologic properties at comparable levels to the non-distracted nerves. Nerves with direct coaptation presented an overall superior regeneration pattern. The findings in end-to-end repairs distracted at 8 weeks and those of grafted nerves at 12 weeks were comparable to those in distracted normal nerves. The morphology of the distracted nerves appeared to be more organized than that observed in the non-distracted nerves

OBJECTIVES: This study sought individual-level data on diesel exhaust exposure and lung function among adolescents in Harlem as part of a community-driven research agenda. METHODS: High school students administered in-person surveys to seventh grade students to ascertain information on demographics, asthma history, and self-reported and maternal smoking. Urine samples were assayed for 1-hydroxypyrene (1-HP), a marker of diesel exhaust exposure, and cotinine, a marker of tobacco smoke exposure. Computer-assisted spirometry was used to measure lung function. RESULTS: Three quarters (76%) of the participating students had detectable levels of 1-HP. Three students (13%) had an FEF25-75 of less than or equal to 80% of their predicted measurements, and 4 students (17%) had results between 80% and 90% of the predicted value, all of which are suggestive of possible lung impairment. CONCLUSIONS: These data suggest that most adolescents in Harlem are exposed to detectable levels of diesel exhaust, a known exacerbator and possible cause of chronic lung disorders such as asthma. Community-driven research initiatives are important for empowering communities to make needed changes to improve their environments and health

BACKGROUND:The purpose of this study was to describe the computed tomography (CT) findings in pancreatic tuberculosis (PT). METHODS:We retrospectively reviewed the CT features in six patients with PT, three of whom had AIDS. RESULTS:Pancreatic lesion masses were found in four patients, small (< 1 cm) low-attenuation pancreatic nodules in one, and diffuse enlargement of the pancreas in one. The pancreatic lesion masses were found in all the non-AIDS patients and in one patient with AIDS and were located in the head of the pancreas in two cases and involved the body, neck, and head of the gland in the other two. The masses showed low attenuation in two cases, soft-tissue attenuation in one, and appeared as an infiltrating inhomogeneous lesion with retropancreatic spread, encasing the celiac trunk and superior mesenteric artery in one. Low-attenuation peripancreatic and/or periportal adenopathies with peripheral rim enhancement were found in three cases, and slight bile duct dilatation was evident in four. Four patients had disseminated tuberculosis, whereas pancreatic and peripancreatic tuberculosis were the sole manifestation of tuberculosis in the other two. CONCLUSION/CONCLUSIONS:The present data suggest that PT usually appears as a nonspecific focal lesion mass in HIV-seronegative patients, whereas there is a variable spectrum of CT findings including focal lesion mass, multiple small low-attenuation pancreatic nodules, or diffuse enlargement of the gland in AIDS patients. Low-attenuation peripancreatic and periportal adenopathies with peripheral rim enhancement and other data of disseminated tuberculosis are ancillary findings that should support a diagnosis of PT.