Faculty Bibliography

Twelve patients between 0.4 and 7.8 months of age were treated by an endoscopic approach to strip craniectomy. Nine patients had sagittal suture involvement. Two patients had a single unilateral lambdoid suture synostosis, and one patient had a combination of a right coronal synostosis and a metopic synostosis. Postoperatively, all patients were placed in cranial remodeling helmets and the results showed that the estimated blood loss ranged from 5 cc to 150 cc, with blood transfusion required in only one patient. All patients were discharged from the hospital by day 2, and all patients had an improvement in their cranial head shape. The specific technique of using the endoscope to aid in performing a strip craniectomy will be discussed. Nine endoscopically treated patients with the diagnosis of sagittal suture synostosis were compared with nine patients treated by using the Marchac remodeling techniques. The mean operative time (1.6 hours versus 3.5 hours), estimated blood loss (43 cc versus 168 cc), hospital costs ($11,671 versus $36,685), and length of stay (1.16 days versus 5.1 days) were less by using the endoscopic technique. All nine patients treated by using the Marchac technique required a blood transfusion, whereas only one patient was transfused in the endoscopically treated group

In accessory neuropathy electrodiagnosis, upper trapezius compound muscle action potential (CMAP) latencies and amplitudes are commonly measured. The few prior reports describing middle and lower trapezius recording have traditionally emphasized latency value determination. The utility of amplitude measurement with middle and lower trapezius recording has not, to our knowledge, been previously described in individual patients with accessory neuropathy. We report three patients (A-C) who developed unilateral accessory neuropathy following surgical procedures. Accessory nerve conduction studies were performed with surface recording over the upper, middle, and lower trapezius muscles. Latency values were normal except for a prolonged lower trapezius latency value in patient B. Side-side trapezius amplitude comparisons revealed striking asymmetries from all three recording sites in patients A and B (71-95% CMAP amplitude decrements) and in the lower trapezius recording of patient C. Middle and lower trapezius side-side CMAP amplitude comparisons may increase the sensitivity of accessory neuropathy electrodiagnosis

OBJECTIVES: Routine carpal tunnel electrodiagnosis frequently includes median (MPW) and ulnar (UPW) palm-wrist mixed nerve conduction latency determinations over 8 cm. Despite widespread use, normative palmar latency difference (PLD) and UPW values, and the relative utility of onset latency (OL) or peak latency (PL) measurements are controversial. The current study was conducted to determine normative values for these parameters. METHODS: MPW and UPW studies were performed unilaterally in 33 normal controls. The PLD-OL and PLD-PL were calculated. The mean, range, standard deviation, and upper limits of normal were determined. 74 hands (50 patients) with both clinical and electrophysiologic median neuropathy were also studied. RESULTS: The abnormal MPW and UPW cut-offs were both 1.8 ms (OL), and 2.3 ms (PL). The abnormal PLD cut-offs were 0.5 ms (OL and PL). Using either OL or PL, PLD parameters were similar within controls, and also within CTS patients. Using either OL or PL, UPW parameters were similar between controls and CTS patients. CONCLUSIONS: An abnormal PLD cut-off of 0.5 is recommended. This is slightly higher than some prior recommendations, however it should minimize the likelihood of false positive studies. Onset and peak latency measurements are likely to have similar clinical utility

The causes of prolonged requirement for mechanical ventilation in the intensive care unit (ICU) are currently a subject of investigation. Critical illness polyneuropathy (CIP), an axonal polyneuropathy that frequently occurs with prolonged sepsis and multi-organ failure, has been cited as a frequent cause of difficulty with weaning from a ventilator. The relative contribution of diaphragmatic denervation in ICU patients with and without CIP has not been definitively determined. We reviewed 102 ventilator dependent intensive care unit (ICU) patients. Critical illness polyneuropathy (CIP) was diagnosed based upon electrodiagnostic criteria. Electrodiagnostic studies included diaphragmatic needle electromyography (EMG) to evaluate for diaphragmatic denervation. The medical charts of the patients with diaphragmatic denervation were reviewed for etiologies other than CIP for the diaphragmatic denervation. Our results suggest: 1) Respiratory impairment in ICU patients may often be unrelated to either CIP or diaphragmatic denervation; 2) Only about half of ventilator dependent CIP patients have diaphragmatic denervation; 3) Diaphragmatic denervation in ICU patients frequently may be attributable to causes other than CIP

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

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