Patients undergoing elective surgery typically fast for 8-12 hours before surgery. However, oral preoperative carbohydrate ingestion may increase postoperative insulin sensitivity and reduce complications. To determine the effects of carbohydrate supplementation prior to CABG or spinal surgery, 38 patients were randomized to receive a carbohydrate supplement or to fast for 12 hours preoperatively. Baseline and postoperative measurements of insulin sensitivity were completed using the short insulin tolerance test and homeostasis model assessment (HOMA). Patient discomfort was measured immediately before surgery. Insulin sensitivity was not significantly different between groups. However, the supplemented group experienced a significantly smaller rise in glucose levels following surgery (p=0.03) and had higher postoperative HOMA-β scores (p=0.02). Fasted patients were significantly more thirsty (p=0.01), hungry (p=0.04) and anxious (p=0.01) before surgery and experienced a significantly longer hospital stay (p=0.008). Carbohydrate supplementation improved outcomes, warranting re-evaluation of fasting practices prior to major surgery.

Patients undergoing elective surgery typically fast for 8-12 hours before surgery. However, oral preoperative carbohydrate ingestion may increase postoperative insulin sensitivity and reduce complications. To determine the effects of carbohydrate supplementation prior to CABG or spinal surgery, 38 patients were randomized to receive a carbohydrate supplement or to fast for 12 hours preoperatively. Baseline and postoperative measurements of insulin sensitivity were completed using the short insulin tolerance test and homeostasis model assessment (HOMA). Patient discomfort was measured immediately before surgery. Insulin sensitivity was not significantly different between groups. However, the supplemented group experienced a significantly smaller rise in glucose levels following surgery (p=0.03) and had higher postoperative HOMA-β scores (p=0.02). Fasted patients were significantly more thirsty (p=0.01), hungry (p=0.04) and anxious (p=0.01) before surgery and experienced a significantly longer hospital stay (p=0.008). Carbohydrate supplementation improved outcomes, warranting re-evaluation of fasting practices prior to major surgery.

Minimally invasive spine surgery (MISS) has proven to be advantageous over traditional open surgery as it minimizes the likelihood of tissue damage and infections. During MISS, surgeons create small incisions to allow access to the surgery site, however, opting for smaller incisions decreases the surgeon’s field of vision. To compensate, surgeons rely on preoperative and intraoperative ionizing imaging technologies for guidance. Conventional localization of the spine, registration of digital images to the patient during surgery, depends heavily on the surgeon’s anatomical knowledge and their experience. Preoperative images are typically created using 3D technology while intraoperative images use 2D technology. While the integration of preoperative 3D images and intraoperative 2D images can provide valuable assistance, patient’s preoperative and intraoperative positions do not coincide leading to additional use of ionizing imaging. The objective of this research was to propose a workflow that assists with image registration for MISS. The main component of the workflow was the creation of a script that automatically generates patient-specific digital guides, which will then be manufactured, to align the patient’s intraoperative and preoperative body position. By aligning the patient’s positions, the 3D printed surgical guide serves as a shared feature between the preoperative digital image and the actual patient. This allows for the intraoperative image to be registered to the preoperative image more accurately. Additionally, the guide acts as an attachment site for any additional instrument guides/supports. The surgical guide generating script utilizes the skin contour of patient’s torso region, extracted from medical images, to automatically produce the guide’s horizontal and vertical components. Adjustments are made to the components using CAD software before proceeding to manufacturing, via 3D printing, and assembly of the guide. To validate the workflow, more specifically the script’s ability to automatically generate surgical guides that fit over the patient’s back, a guide was created for a mannequin. The maximum gap between the mannequin and the horizontal components was 0.8 cm and 1.5 cm for the vertical component.

The anterior approach to cervical spine surgery is associated with many possible complications. Dysphagia has commonly been reported as one of these complications. A closer examination of the reports of dysphagia following anterior cervical spine surgery, however, reveals that while new onset transient dysphagia is often mentioned, long-term (greater than 48 hours) dysphagia has not been well described. In this article, we report the case of a 29-year-old female with long-term recurrent dysphagia following cervical spine surgery using the anterior approach. The important point about this case is that our patient's symptoms suddenly recurred for the first time after, nearly a two-month period of normal swallowing. Consequently, this patient has required multiple dilations. As a result, despite an initial lack of swallowing dysfunction or the return of normal swallowing, clinicians should be aware of the importance of reassessing swallowing in patients who have undergone cervical spine surgery using the anterior approach.

Symptomatic spinal disorders affect a large proportion of the population and are associated with substantial morbidity, social burden, and economic impact. Spine surgery interventions can provide excellent results in carefully selected patients whose symptoms fail to improve with non-operative management, but an evidence-based approach is paramount to optimize outcomes and rigorous standards of health research methodology are critical to avoid misleading conclusions. This thesis aimed to investigate and apply modern innovations in health research methodology to the field of spine surgery. It consists of seven chapters divided between three sections: randomized controlled trials, observational studies, and systematic reviews and meta-analyses. By applying the findings of each chapter, clinicians, researchers, and other evidence users can advance the credibility of future research and enhance the care of patients with spinal disorders. / Thesis / Doctor of Philosophy (PhD)

Postoperative spinal patients were randomly assigned to one of three treatment conditions and were taught five adaptive movements by occupational therapists. The Control group received routine hospital occupational therapy; the Placebo group participated in an imagery relaxation task unrelated to the mental practice task of the Imagery group, which was shown line drawings of the adaptive movements under study, provided movement instructions, and asked to mentally practice each movement in a familiar, daily living situation. Thirty-five patients returned for follow-up, and a measure of outcome was obtained through the use of a quantified movement assessment instrument. Subjective ratings for anxiety, rumination, and imagery were made by the occupational therapists. An occupational motoric-symbolic rating scale was developed to assess the symbolic portion of the patient's job experience. Statistical procedures including chi square, analysis of variance, and Pearson correlation were performed. Results were in the predicted direction although statistical significance was not achieved. Possible explanations for the obtained results were discussed.

A cirurgia da coluna vertebral tem se desenvolvido muito nos últimos anos em decorrência da evolução dos sistemas de fixação. O comportamento da interface do parafuso com o osso continua sendo um aspecto não muito dominado. Como o parafuso é a âncora de sustentação, o trabalho procura investigar as técnicas de introdução do parafuso pedicular. Para atingir esse objetivo desenvolvemos o trabalho por meio de estudo com ensaios mecânicos de arrancamento e estudo histológico. Dois tipos de parafusos pediculares foram utilizados: parafuso pedicular do sistema USIS (Ulrich) e parafuso pedicular do sistema USS (Synthes). Os ensaios de arrancamento foram realizados em corpos de prova de madeira e poliuretano. O estudo histológico foi realizado em vértebras lombares de cadáver humano. No estudo envolvendo o parafuso USIS, foram testados os seguintes parâmetros: orifícios feitos com sonda e orifícios feitos com broca, todos do mesmo diâmetro do diâmetro interno do parafuso. Também foi testado o efeito do macheamento em relação ao não macheamento, nos orifícios feitos com broca. No estudo com os parafusos USS foram testados o efeito do diâmetro do orifício piloto tanto no estudo histológico como no arrancamento. No arrancamento destes parafusos também foi testado o efeito do tipo de orifício feito com sonda e com broca. O trabalho foi dividido em etapas: Primeira etapa foi o estudo de arrancamento do parafuso USIS; segunda etapa, estudo histológico de vértebra instrumentada com parafuso USIS, esta parte do trabalho foi constituída por análise de microscopia de luz e microscopia eletrônica de varredura; terceira etapa foi o arrancamento do parafuso USS; e quarta etapa foi o estudo histológico de vértebra instrumentada com parafuso USS. Os resultados da primeira etapa demonstraram que sonda teve efeito melhor do que broca, porque o resultado dos ensaios de arrancamento nos orifícios feitos com sondas teve maior força de arrancamento do que nos orifícios feitos por brocas. Na segunda etapa, análise histológica, verificou-se que os orifícios feitos por sonda apresentaram-se menores e com menor índice de fragmentação ao redor dos orifícios. Esses feitos tiveram diferença estatística significante, tanto na primeira, quanto na segunda etapa. Com relação ao macheamento não foi constatada diferença entre o não macheamento, em nenhuma das duas etapas. Na terceira etapa foi observado que, quando o orifício piloto ultrapassa o diâmetro interno do parafuso, ocorre tendência de queda na força de arrancamento de modo significativo, enquanto que orifício menor que o orifício piloto não tende a causar muita diferença na força de arrancamento em relação ao orifício correspondente ao diâmetro interno do parafuso. Também foi observado que o orifício feito com sonda oferece melhor força de ancoragem do que orifício feito com broca. Na quarta etapa foi constatado que quanto menor a broca para abrir o orifício piloto, menor o diâmetro do orifício, e não houve diferença significativa quanto ao índice de fragmentação ao redor do orifício entre os diferentes tamanhos de broca. Como conclusão pode-se dizer que sonda é melhor para se fazer o orifício piloto, uma vez que alarga menos o orifício, lesa menos as trabéculas ao redor do orifício e proporciona maior força de ancoragem do que broca. Também se pode concluir que o instrumental de menor diâmetro para abertura do orifício piloto é melhor, e o ponto crítico seria o diâmetro interno do parafuso. Não se deve fazer orifício piloto com instrumento de diâmetro maior que o diâmetro interno do parafuso. Não se constatou vantagem em relação ao fato de realizar ou deixar de realizar o macheamento. / Spine surgery has developed a lot in the last years because of the evolution of the fixation system. The behavior of a screw in the bone is still unknown in many ways. Because the screw is the anchor of sustentation, this work tries to find the answers involving the pedicle screw fixation. To reach this objective we developed this work based on mechanical and histological studies. Two kinds of pedicle screws were used: pedicle screw of the USIS (Ulrich) and pedicle screw of the USS system (Synthes). The pullout tests were made in wood and polyurethane. The histological study was done in lumbar vertebra of humans. In the study about the USIS screw, the follow parameters were tested: hole done with probe and hole done with drill, all of the same inner diameter of the screw. The effect of tapping and not tapping the hole done with drill was tested. In the USS screw study, the effect of the diameter pilot hole in the pullout tests and its historical analysis was seen. In the pullout tests of these screws, both kind of holes done with probes and a drill were tested. The work was divided into stages; first stage was the study of the pullout of the USIS screw; second stage was two studies, a light-microscopic one and a sweeping-electronic-microscope one of the slides of the instrumented vertebra with USIS screws; third stage was the study of the USS screws pullout comparing the relationship between the diameter of the holes and the inner diameter of the screw together with the type of hole (drill and probe); fourth stage was light-microscopic histological study of the instrumented vertebras which had had USIS screws. Results of the first stage showed that probes were more efficient than drills because the mechanical tests of pullouts from probe-made-holes showed the need of the use of a stronger force. In the second stage, a light-microscopic analysis showed that probe-made-holes had a lesser minimum diameter and a lower index of fragmentation than drill-made holes. With relation to the tapping, there was no difference between the holes. Under electronic microscope sweeping, it was seen that probes betters compact the bone around the screw. In the third stage, it was seen that when 9 the pilot orifice was greater than the screws internal diameter a significantly lower force was needed for pullout, while when the pilot orifice was smaller it did not significantly increase the force needed. It was also seen that probe-made-holes had a better anchorage than the drill-made-holes. In the fourth stage, the histological analysis of the slides done with light-microscopy showed that the smaller the diameter of the drill the smaller minimum diameter; there was no significant difference between fragmentation indexes. Conclusion: Probes are better than drills to make a pilot hole because they cause less damage to the surrounding bone and give a stronger anchorage for the screw; the smaller the instrument used to make the pilot hole, better will be the strength of the screws anchorage; the critical point which the hole must not exceed is the internal diameter of the screw. Tapping, or not, makes no difference to the anchorage.

Foi realizado estudo experimental com a finalidade de avaliar a participação do osso cortical e osso esponjoso dos pedículos vertebrais, na fixação dos parafusos pediculares. Foram utilizados 10 segmentos de coluna lombar de adultos, retirados durante autópsia. O diâmetro dos pedículos das vértebras de L1 a L5 foram avaliados, considerando o diâmetro total e o diâmetyro do osso esponjoso, tendo sido realizadas essas medidas por meio de tomografia computadorizada e medida direta. Os segmentos da coluna vertebral foram divididos em dois grupos para o estudo, sendo que cada grupo era formado por 5 conjuntos de segmentos da coluna lombar. No primeiro grupo a perfuração era realizada segundo os pontos de orientação utilizados nos procedimentos cirúrgicos ( faceta articular e processo transverso). No segundo grupo foi realizado corte transversal na porção média do pedículo, de modo que a perfuração e introdução dos parafusos no seu interior foram efetuados sob visão diereta. Após a perfuração dos pedículos utilizando-se broca de 3 mm, os parafusos eram introduzidos no interior do pedículo vertebral em ordem crescente de seus diâmetros, até que fosse observada alteração estrutural do pedículo, que eram avaliados por meio de medidas sucessivas, utilizando-se paquímetro e observação direta. Foram utilizados parafusos com diâmetro que variou de 3 a 12,5 mm, com progressão de 0,5 mm. Quando o diâmetro do parafuso excedia a resistência estrutural do pedículo, duas lesões foram observadas, a deformação plástica e o rompimento. No grupo I houve um número maior de deformação plástica, mas pelos cálculos estatísticos não houve diferença significativa entre os grupos. Os diâmetro tomográficos obtidos pela medida tomográfica e medida direta apresentaram-se diferentes e sem correlação entre si. No grupo II, como os parafuos foram introduzidos de modo mais centralizado, houve maior número de parafusos com diâmetro maior que o diâmetro do osso esponjoso, mas também não apresentou diferença entre os grupos, segundo avaliações estatísticas. Análise dos valores do diâmetro pedicular, diâmetro do osso esponjoso e do parafuso de maior diâmetro introduzido sem lesar o pedículo permitiu observar que a camada de osso cortical do pedículo foi pouco ocupada pelo parafuso em ambos os grupos. O valor médio da porcentagem do diâmetro do pedículo ocupado pelo parafuso no grupo I foi de 70,7% e no grupo II 75,34%. Foi observado que os parafusos, de um modo geral, apresentaram ancoragem principalmente na porção de osso esponjoso do pedículo vertebral, tendo sido pequena a porcentagem de osso cortical do pedículo vertebral utilizado para a sua ancoragem. / Spine surgery has developed a lot in the last years because of the evolution of the fixation system. The behavior of a screw in the bone is still unknown in many ways. Because the screw is the anchor of sustentation, this work tries to find the answers involving the pedicle screw fixation. To reach this objective we developed this work based on mechanical and histological studies. Two kinds of pedicle screws were used: pedicle screw of the USIS (Ulrich) and pedicle screw of the USS system (Synthes). The pullout tests were made in wood and polyurethane. The histological study was done in lumbar vertebra of humans. In the study about the USIS screw, the follow parameters were tested: hole done with probe and hole done with drill, all of the same inner diameter of the screw. The effect of tapping and not tapping the hole done with drill was tested. In the USS screw study, the effect of the diameter pilot hole in the pullout tests and its historical analysis was seen. In the pullout tests of these screws, both kind of holes done with probes and a drill were tested. The work was divided into stages; first stage was the study of the pullout of the USIS screw; second stage was two studies, a light-microscopic one and a sweeping-electronic-microscope one of the slides of the instrumented vertebra with USIS screws; third stage was the study of the USS screws pullout comparing the relationship between the diameter of the holes and the inner diameter of the screw together with the type of hole (drill and probe); fourth stage was light-microscopic histological study of the instrumented vertebras which had had USIS screws. Results of the first stage showed that probes were more efficient than drills because the mechanical tests of pullouts from probe-made-holes showed the need of the use of a stronger force. In the second stage, a light-microscopic analysis showed that probe-made-holes had a lesser minimum diameter and a lower index of fragmentation than drill-made holes. With relation to the tapping, there was no difference between the holes. Under electronic microscope sweeping, it was seen that probes betters compact the bone around the screw. In the third stage, it was seen that when the pilot orifice was greater than the screws internal diameter a significantly lower force was needed for pullout, while when the pilot orifice was smaller it did not significantly increase the force needed. It was also seen that probe-made-holes had a better anchorage than the drill-made-holes. In the fourth stage, the histological analysis of the slides done with light-microscopy showed that the smaller the diameter of the drill the smaller minimum diameter; there was no significant difference between fragmentation indexes. Conclusion: Probes are better than drills to make a pilot hole because they cause less damage to the surrounding bone and give a stronger anchorage for the screw; the smaller the instrument used to make the pilot hole, better will be the strength of the screw\'s anchorage; the critical point which the hole must not exceed is the internal diameter of the screw. Tapping, or not, makes no difference to the anchorage.

Bibliography: leaves 160-171. / xii, 171 leaves, [9] leaves of plates : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Evaluates the effect of an anterior surgical approach and antero-lateral inter-body fusion of the cervical spine on spinal cord blood flow and electrical function using a sheep model. / Thesis (M.D.)--University of Adelaide, Dept. of Orthopaedic Surgery & Trauma, 1993?

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Neck pain is a common phenomenon that occurs in a large percentage of the population every day. While many occurrences are not deemed critical such as those from muscle strain which can be treated with rest and pain medication, others due to sports injuries, whiplash from car accidents, bad posture or degeneration of the intervertebral disc can be quite severe. In extreme cases failure of the vertebra(e) or the intervertebral disc requires surgery and possibly the use of cervical implants. Where intervertebral discs fail due to herniation or Degenerative Disc Disease (DDD), Anterior Cervical Discectomy and Fusion (ACDF) is a common surgical method used to remove the a ected disc and replace it with a cervical cage implant. These implants are designed to restore the height between the vertebrae, allowing bone from both vertebrae to grow through them and mineralise. Additive Manufacturing (AM) technologies can produce parts with complex geometries not possible using conventional manufacturing methods. This design freedom, coupled with CT scans of a patient, allow for tailoring an implant to the speci c anatomy of the a ected vertebrae using CAD software. Such an approach must be regulated and shown to be technically and commercially feasible before it can be implemented in industry. This study sought to develop a framework for manufacturing customized cervical cage implants using additive manufacturing. The e cacy of customization to reduce the risk of subsidence was investigated by means of non-destructive and destructive mechanical testing on six cadaver specimens, using readily available PEEK cage implants as a benchmark. The results showed that the customized implant was comparable to the PEEK, with no statistically signi cant di erence between the two. In extreme cases, where PEEK implants cannot be used, customized implants could be a suitable alternative to reduce the risk of subsidence. A manufacturing cost analysis was conducted to determine economic feasibility. The estimated cost and selling price of the customized implants under various utilization scenarios and mark-ups was compared to readily available PEEK implants. The estimated selling prices of the customized implants compared favourably to the PEEK verifying the economic viability of using AM. / AFRIKAANSE OPSOMMING: Nek pyn is 'n algemene verskynsel wat daagliks na tevore kom in die bevolking. Baie gevalle word nie as krities geklasi seer nie soos byvoorbeeld spier pyn wat behandel kan word deur genoegsame rus en pyn medikasie. Pyn wat deur sportbeserings, sweepslag beserings 'whiplash' tydens motor ongelukke, verkeerde postuur, of deur slytasie van 'n intervertebrale skyf veroorsaak is, word dikwels as ernstig geklasi seer. In ekstreme gevalle waar die werwel(s) of die inervertebrale skyf(we) faal, sal chirurgie en servikale inplantate moontlik nodig wees. Waneer intervertebrale skywe faal weens herniatie of Degeneratiewe Skyf Siekte (DDD) kan 'n algemene chirurgiese metode, Anterieure Servikale Discectomie en Fusie (ACDF), gebruik word om die gea ekteerde skyf te verwyder en dit te vervang met 'n servikale samesmelting implantaat. Hierdie implantate herstel die hoogte tussen rugwerwels en is ontwerp sodat die been deur dit kan groei en mineraliseer. Komplekse geometrieë kan vervaardig word deur toevoegingsvervaardiging (AM) tegnologieë. Die ontwerp vryheid, gepaard met CT-skanderings en CAD-sagteware stel mens in staat om die geometrie van die implantaat aan te pas tot die spese eke anatomie van die gea ekteerde vertebra. So 'n benadering moet gereguleer word en eers tegnies en kommersieel uitvoerbaar bewys word voordat dit in die bedryf geïmplementeer kan word. Hierdie studie poog verder om 'n raamwerk vir die vervaardiging van persoonlike servikale implantate deur middel van toevoegingsvervaardiging te ontwikkel. Die doeltre endheid van persoonlike implantate om te verhoed dat die chirurg die eind-plaat beskadig, en sodoende die risiko van insakking te verminder, is ondersoek deur middel van meganiese toetse op ses kadawer monsters. Hierdie toetse is gedoen met behulp van geredelik beskikbaar PEEK servikale implantate as 'n maatstaf. Die resultate het getoon dat die persoonlike- en PEEK implantate vergelykbaar is. In moontlike gevalle waar PEEK implantate nie geskik sou wees nie, kan persoonlike implantate 'n alternatiewe opsie wees om die risiko van insakking te verminder.