Filip Šámal

Morphological evidence of collateral sprouting of intact afferent and motor axons of the rat ulnar nerve demonstrated by one type of tracer molecule

In our experimental paradigm we sutured the distal stump of a transected musculocutaneous nerve to an intact ulnar nerve of the rat in an end-to-side fashion. We demonstrated the formation of collateral sprouts from intact afferent and motor axons by application of one type of molecule conjugated by two different fluorophores (Fluoro-Ruby and Fluoro-Emerald). Fluoro-Ruby and Fluoro-Emerald were applied distal to end-to-side suture into fresh cut ends of the ulnar and musculocutaneous nerves, respectively. Formation of collateral sprouts was evidenced by findings of mixed (a yellow to orange color) fluorescence labeling of spinal motoneurons and dorsal root ganglia neurons. Colocalization of two different tracers retrogradely transported to the neurons was verified by the individual green and red fluorescence profiles analyzed by means of the computer-assisted image-analyzing system. Our results unequivocally demonstrate that a nerve stump attached to an intact nerve can induce collateral sprouting of both afferent and motor axons.

Reinnervation of the rat musculocutaneous nerve stump after its direct reconnection with the C5 spinal cord segment by the nerve graft following avulsion of the ventral spinal roots: a comparison of intrathecal administration of brain-derived neurotrophic factor and Cerebrolysin

Experimental model based on the C5 ventral root avulsion was used to evaluate the efficacy of brain-derived neurotrophic factor (BDNF) and Cerebrolysin treatment on motor neuron maintenance and survival resulted in the functional reinnervation of the nerve stump. In contrast to vehicle, BDNF treatment reduced the loss and atrophy of motor neurons and enhanced the regrowth axon sprouts into the distal stump of musculocutaneous nerve. However, the axon diameter of the myelinated fibers was smaller than those of control rats. The morphometric results were related to a low score in behavioral test similar to vehicle-treated rats. Cerebrolysin treatment greatly protected the motor neurons against cell death. Moreover, morphometric features of myelinated axons were better than those of rats treated with vehicle or BDNF. The mean score of grooming test suggested better results of the functional motor reinnervation than after BDNF administration. The majority of rescued motor neurons regenerating their axons through nerve graft in both BDNF- and Cerebrolysin-treated rats expressed choline acetyltransferase immunostaining. The results demonstrate that BDNF has more modest effects in preventing the death of motor neurons and functional recovery of injured motor nerve after root avulsion than Cerebrolysin.

Medical consultations and the sharing of medical images involving spinal injury over mobile phone networks

BACKGROUND The transmission of medical images and other data over mobile phone networks may facilitate remote medical consultations between neurosurgeons and regional hospitals treating spinal injury patients. The aim of this study was to compare the efficacy of mobile phone consultations with standard hospital workstation consultations in spinal injury patients. METHODS The images were exported over the Internet from surrounding local hospitals through the Picture Archiving and Communication System, in DICOM III format, to the central hospital server. The xVision browser was used to view the acquired images on a standard workstation. The data were also exported to the secured hospital Web server IIS60 and converted to JPEG format to enable remote physician access and consultation. The remote consulting physician connected to this server by mobile phone using the phones Internet browser. A second physician, blind to the mobile phone results, evaluated the same images at a workstation in the hospital. The results of the mobile phone consultations were compared with the results from standard workstation consultations. RESULTS There was no difference in the quality of spinal computed tomographic/magnetic resonance images viewed on the phone screen compared with on the workstation. More importantly, the final diagnoses made by mobile phone did not differ from those made by workstation consultations. A transfer to the department of neurosurgery was required after consultation in 11 patients. CONCLUSION Mobile phone consultations for patients with spinal injuries was as effective as workstation consultations. Mobile phone consultations can increase the expertise available to regional hospitals, which are often the first responders to medical emergencies.

Application of Transcranial Color-Coded Sonography in Severe Brain Injury

Transcranial color-coded sonography (TCCS) monitoring of severe brain injury patients may reveal various pathological hemodynamic changes. According to changes in flow velocities in basal brain arteries, the presence of brain hyperemia, vasospasms, and oligemia can be detected. The study included a group of 20 patients with severe brain injury. TCCS measured flow velocities and ICP values were monitored on a daily basis in the course of a week after injury. In nearly 50 % of patients significant hemodynamic changes occurred. The most frequent pathological finding was hyperemia (31.8 %), followed by vasospasm (10.9 %) and oligemia (9.1 %). In 42.7 % of patients increased flow velocities were registered and only 9.1 % of records were within the normal range of values. The most substantial elevation in time-averaged mean velocity occurred from the second to the sixth day after injury. In a subgroup of patients with raised intracranial pressure 41.6 % of flow velocity (FV) measuring met the TCCS criteria for hyperemia compared with 26 % in a subgroup of patients without intracranial pressure (ICP) elevation. The study showed that hemodynamic changes after severe brain injury are relatively common findings and that TCCS is a useful bed-side tool for the monitoring of intracranial hemodynamic changes.

End-to-side anastomosis of peripheral nerve in experimental and clinical model

Abstract The results of 13 patients with end-to-side anastomosis of the axillary nerve to various donor nerves were presented. The results were evaluated by means of functional and electrophysiological methods following avulsion and subsequent reconstruction of the brachial plexus. End-to-side anastomosis of the rat musculocutaneous nerve ( n =12), with the ulnar one, was used in the experimental model. The retrograde tracers were applied to prove the reinnervation. Fair and good results were achieved in neurotization of the axillary nerve in 75% of patients with follow-up longer than 24 months. Electrophysiology proved reinnervation in 100% of the patients. The average muscle strength, according to the muscle test, was 3.80. The functional recovery started within 7–12 months postoperatively. Retrograde staining in the experimental model demonstrated the reinnervation of the rat bicep muscles after 3 months from end-to-side anastomosis, mainly by collateral reinnervation from the ulnar nerve. The ulnar nerve motoneurons (70±13) were able to send off collateral sprouts from their intact axons into the musculocutaneous nerve. Other motoneurons of the same pool (21±4) regenerated axons directly into the musculocutaneous nerve without collateral sprouting, probably due to the axonotmesis of the motor fibers during the preparation of the perineurial window. Our results demonstrated that end-to-side anastomosis of the peripheral nerve might successfully be used for reinnervation procedures of a brachial plexus injury, mainly in cases with insufficient sources of motor nerve fibers from neighboring intact motor nerves.

Comparison of Biochemical Markers of Muscle Damage and Inflammatory Response Between the Open Discectomy, Microsurgical Discectomy, and Microsurgical Discectomy Using Tubular Retractor

BACKGROUND One of the methods to compare the invasiveness of different surgical techniques objectively is to measure the levels of biochemical markers of systemic inflammatory response and muscle damage. METHODS A total of 120 patients undergoing surgery for symptomatic disc herniation at L4-L5 and L5-S1 were enrolled in the study. Patients were operated on using open discectomy (OD), microsurgical discectomy (MD), or microsurgical discectomy with tubular retractor (MD-TUB). Myoglobin (MYO) and creatine kinase (CK) levels were used as indicators of muscle damage, and interleukin-6 (IL-6) and C-reactive protein (CRP) levels were used as indicators of systemic inflammatory response. Sampling and analysis of samples were performed preoperatively and on postoperative days 1, 3, and 7. Levels of postoperative low back pain and radicular pain were recorded on a 10-grade visual analog scale. Statistical evaluation was performed using the analysis of variance test. RESULTS MYO concentrations in the MD-TUB group on postoperative day 1 were significantly lower than in the MD and OD groups. CK values on postoperative day 1 were significantly lower in microsurgical techniques (MD and MD-TUB) than in the OD group. The lowest IL-6 levels were found in the MD-TUB group, followed by the MD and OD groups. Differences in the IL-6 levels were significant between the groups on postoperative day 1. On all postoperative days that were monitored, values of CRP in the MD-TUB group were significantly lower compared with the MD and OD groups. Lower values in the MD group versus OD group were not statistically significant. CONCLUSION All studied techniques showed similar efficacy in reducing radicular pain. The microsurgical diskectomy using a retractor in comparison with MD and OD is friendlier toward the paraspinal muscles, but the difference is significant only for the MYO levels. The total stress inflammatory response exhibited by patients undergoing the MD-TUB technique is significantly lower compared with the MD and OD techniques.