Thesis (M.Eng.). / Written for the Dept. of Biomedical Engineering. Title from title page of PDF (viewed 2008/07/29). Includes bibliographical references.

Com o objetivo de avaliar os efeitos do tempo da descompressão medular em 50 ratos, machos, da raça Wistar, criou-se um modelo experimental de compressão medular através da passagem de uma fita de tecido (cetim), que reduz em 30% o diâmetro do canal vertebral na região da coluna torácica após laminectomia (TIX E TX). Os animais foram distribuídos em cinco grupos com 10 ratos cada, sendo: grupo A, controle da técnica de exposição medular atraumática, sem lesão; grupo B, submetidos à compressão medular, seguida de descompressão cinco minutos após a lesão; nos grupos C e D, realizou-se o mesmo procedimento do grupo B, porém a descompressão ocorreu 24 e 72 horas após a compressão, respectivamente; os ratos do grupo E sofreram compressão, sem descompressão até o fim do experimento na quarta semana, quando os 50 ratos foram submetidos à eutanásia. Todos os animais com compressão (B, C, D e E) apresentaram paraplegia no pós-operatório imediato. A recuperação neurológica foi avaliada através do potencial evocado motor, da escala BBB de capacidade locomotora e do exame anatomopatológico do sítio da lesão. Observou-se relação direta entre o potencial de recuperação neurológica e o tempo da descompressão medular nos três métodos de avaliação / With the objective of evaluating the effects of medullary decompression time in 50 male Wistar rats, an experimental model of medullary compression was created, through the insertion of a satin tape, which reduces in 30% the diameter of the vertebral canal at the region of the thoracic column after laminectomy (TIX and TX). The animals were distributed in five groups with 10 rats each, as follows: group A: control of the technique of atraumatic medullary exposure, with no lesion; group B, submitted to medullary compression, followed by decompression five minutes after the lesion; groups C and D underwent the same procedure, but decompression was performed 24 and 72 hours after compression, respectively; and finally, rats from group E underwent compression without decompression up to the end of the experiment on the 4th week, when all 50 rats were euthanized. All animals submitted to compression (groups B, C, D and E) presented paraplegia in the immediate post-operative period. The neurological recovery was evaluated through the motor-evoked potential of the BBB scale of locomotor capacity and anatomopathological examination of the lesion site. A direct correlation between the neurological recovery potential and time of medullary decompression was observed at the three evaluation methods

Com o objetivo de avaliar os efeitos do tempo da descompressão medular em 50 ratos, machos, da raça Wistar, criou-se um modelo experimental de compressão medular através da passagem de uma fita de tecido (cetim), que reduz em 30% o diâmetro do canal vertebral na região da coluna torácica após laminectomia (TIX E TX). Os animais foram distribuídos em cinco grupos com 10 ratos cada, sendo: grupo A, controle da técnica de exposição medular atraumática, sem lesão; grupo B, submetidos à compressão medular, seguida de descompressão cinco minutos após a lesão; nos grupos C e D, realizou-se o mesmo procedimento do grupo B, porém a descompressão ocorreu 24 e 72 horas após a compressão, respectivamente; os ratos do grupo E sofreram compressão, sem descompressão até o fim do experimento na quarta semana, quando os 50 ratos foram submetidos à eutanásia. Todos os animais com compressão (B, C, D e E) apresentaram paraplegia no pós-operatório imediato. A recuperação neurológica foi avaliada através do potencial evocado motor, da escala BBB de capacidade locomotora e do exame anatomopatológico do sítio da lesão. Observou-se relação direta entre o potencial de recuperação neurológica e o tempo da descompressão medular nos três métodos de avaliação / With the objective of evaluating the effects of medullary decompression time in 50 male Wistar rats, an experimental model of medullary compression was created, through the insertion of a satin tape, which reduces in 30% the diameter of the vertebral canal at the region of the thoracic column after laminectomy (TIX and TX). The animals were distributed in five groups with 10 rats each, as follows: group A: control of the technique of atraumatic medullary exposure, with no lesion; group B, submitted to medullary compression, followed by decompression five minutes after the lesion; groups C and D underwent the same procedure, but decompression was performed 24 and 72 hours after compression, respectively; and finally, rats from group E underwent compression without decompression up to the end of the experiment on the 4th week, when all 50 rats were euthanized. All animals submitted to compression (groups B, C, D and E) presented paraplegia in the immediate post-operative period. The neurological recovery was evaluated through the motor-evoked potential of the BBB scale of locomotor capacity and anatomopathological examination of the lesion site. A direct correlation between the neurological recovery potential and time of medullary decompression was observed at the three evaluation methods

<p>Degenerativne bolesti kičme nastaju kao posledica promena na dinamičkim segmentima kičmenog stuba. Klinički ove promene se mogu manifestovati u vidu radikulopatije, mijelopatije i radikulomijelopatije. Najče&scaron;će primenjivana metoda operativnog lečenja kod ovih pacijenata je prednja cervikalna diskektomija sa fuzijom koja omogućava adekvatnu anatomsku i funkcionalnu restituciju degenerativno promenjene cervikalne kičme. Imajući u vidu da su već kompromitovane nervne strukture u riziku od dodatnih o&scaron;tećenja u različitim fazama operativnog zahvata primena intraoperativnog neurofiziolo&scaron;kog monitoringa je dobila svoje mesto i u hirur&scaron;kim tretmanima degenerativnih oboljenja kičme. Svrha primene neuromonitoringa je da obezbedi povratnu informaciju hirurgu o promenama u funkciji nervnih struktura pre nego &scaron;to dođe do ireverzibilnih o&scaron;tećenja. Na ovaj način moguće je prevenirati nastanak novog ili pogor&scaron;anje postojećeg deficita. Takođe intraoperativni nalazi neurofiziolo&scaron;kih parametara mogu da ukažu na težinu postojećeg oboljenja i da budu prediktori ishoda lečenja. Ciljevi ove doktorske disertacije bili su utvrđivanje faza operativnog zahvata u kojima najče&scaron;će dolazi do promena u neurofiziolo&scaron;kim parametrima, kao i postojanje korelacije nalaza intraoperativnog neurofiziolo&scaron;kog monitoringa sa preoperativnim kliničkim nalazom pacijenta kao i rezultatima procene ishoda nakon prednje cervikalne diskektomije se fuzijom. Ova studija je obuhvatila 30 pacijenata kod kojih je indikovano operativno lečenje degenerativnih promena u vratnom segmentu kičmenog stuba prednjom mikrodiskektomijom sa fuzijom. Preoperativno je izvođen klinički pregled pacijenata i kori&scaron;teni su Numerička skala bola i Upitnik za pacijente sa bolom u vratnoj kičmi, koji su takođe popunjavani na otpustu i mesec dana nakon operacije. U toku hirur&scaron;ke procedure upotrebom intraoperativnog neurofiziolo&scaron;kog monitoringa registrovani su somatosenzorni (SSEP) i motorni evocirani potencijali (MEP), kao i spontana elektromiografija. Kod svih SSEP do&scaron;lo je do statistički značajnog povećanja amplitude (p&lt;0,05), dok je kod desnog n. medianusa zabeleženo i statistički značajno skraćenje latence (p&lt;0,05). Značajne promene se beleže između početka i kraja operativnog zahvata, kao i u fazi uklanjanja intervertebralnog diska kada dolazi do dekompresije. U vrednostima pražne struje potrebne za dobijanje MEP nije bilo statistički značajnih promena izuzev kod m. triceps brachii obostrano. Kod pacijenata sa radikulopatijom vrednost pražne struje za dobijanje mi&scaron;ićnog odgovora je statistčki značajno niža u odnosu na pacijente sa mijelopatijom (p&lt;0,05). SSEP koreliraju sa poremećajem senzibiliteta, refleksnim odgovorom i bolom. MEP koreliraju takođe sa refleksnim odgovorom, dok negativna korelacija sa manuelnim mi&scaron;ićnim testom pokazuje da klinički očuvana gruba mi&scaron;ićna snaga ne mora biti pokazatelj pravog stanja motornog sistema. Preoperativne vrednosti NDI su se statistički značajno smanjile mesec dana nakon operacije (p&lt;0,05). U vrednostima bola postoji statistčki značajna razlika između svih merenje (p&lt;0,008), izuzev između bola na otpustu i mesec dana nakon operacije (p&gt;0,008). Latenca desnog n.medianusa pokazuje negativnu, a amplituda pozitivnu korelaciju sa vrednostima bola mesec dana postoperativno (p&lt;0,05). Povećanje amplitude i skraćenje latence SSEP ukazuje na značajan stepen dekompresije. Stabilnost MEP ukazuje na intraoperativnu očuvanost motornih puteva i da nije do&scaron;lo do novog motornog deficita niti produbljivanja postojećeg. SSEP i MEP koreliraju sa kliničkim nalazom, dok su vrednosti bola i NDI statistički značajno manje nakon operacije. Ovi rezultati ukazuju da klinički nalaz pacijenta korelira sa neurofiziolo&scaron;kim nalazom, kao i da introperativne promene neurofiziolo&scaron;kih parametara mogu biti prediktivni faktor ishoda operativnog lečenja.</p> / <p>Degenerative spinal diseases are consequence of spondylotic changes on dynamic segments of spinal column. These changes can result in different clinical appearances such as radiculopathy, myelopathy and radiculomyelopathy. The most common surgical procedure used in treatment of this group of patients is anterior cervical discectomy and fusion (ACDF) which can provide adequate anatomical and functional restitution of degenerative cervical spine. Considering the fact that already compromised neural structure can be additionally damaged in different stages of surgical procedure, use of intraoperative neurophysiological monitoring (IONM) has role in surgical treatment of degenerative spinal diseases. The aim of use of IONM is to provide real time feedback for surgeon regarding changes in function of neural structures before irreversible damage occurs. This is the way to prevent new neurological deficit from occurring or to prevent worsening of preexisting deficit. Results of intraoperative monitoring can additionally emphasize severity of disease and help in outcome assessment. The aim of this doctoral thesis was to determine phases of surgical procedure in which changes in neurophysiological parameters occurs most commonly. Another aim was to determine correlation between findings of intraoperative neurophysiological monitoring and clinical assessment and outcome prediction in patients treated with anterior cervical discectomy with fusion. Thirty patients who met inclusion criteria were enrolled in this study. All of them were treated surgically due to degenerative changes of cervical spine and ACDF were performed in all cases. Patients were thoroughly examined before surgery. Detailed neurological examination were performed together with Numeric pain rating scale (NPRS) and Neck Disability index (NDI) questionnaire. NPRS and NDI were applied on discharge from the hospital and one month after surgery. During surgery we registered somatosensory evoked potentials (SSEP), motor evoked potentials (MEP) and spontaneous elektromiography. In all SSEP there were statistically significant increase in amplitude (p&lt;0.05), while in the case of right n. medianus statistically significant shortening of the latency (p&lt;0.05) was recorded. Significant changes are recorded between beginning and the end of the surgical procedure, as well as in the phase of removing of the intervertebral disc when decompression occurs. In the threshold intensity needed to elicit the MEP there were no statistically significant changes except for m. triceps brachii bilaterally. In patients with radiculopathy, the value of the stimulus intensity needed for obtaining muscular response was statistically significantly lower in comparison with patients with myelopathy (p&lt;0.05). SSEP showed the best correlation with sensory disorder, tendon reflexes and pain. MEPs also correlate with tendon reflexes, while a negative correlation with a manual muscle strength testing results shows that clinically preserved muscle strength does not have to be reliable indicator of the motor system condition. Preoperative NDI values were statistically significantly reduced a month after surgery (p&lt;0.05). In pain values there is a statistically significant difference between all measurements (p&lt;0.008), except between pain on release and a month after surgery (p&gt;0.008). The right n.medianus latency shows a negative, and the amplitude shows positive correlation with pain values one month postoperatively (p&lt;0.05). Increasing amplitude and shortening latency of the SSEP indicates a significant degree of decompression. The stability of the MEP indicates the intraoperative preservation of motor pathways and absence of both new motor deficiency or worsening of the existing one. SSEP and MEP correlate with clinical findings, while pain and NDI values are statistically significantly less after surgery. These results indicate that clinical findings in the patients correlate with the neurophysiological findings. Results also points out that the intraoperative changes in neurophysiological parameters can be a predictive factor for the outcome of surgical treatment.</p>