[Volume changes of intervertebral disc and vertebral body after dorsal fusion]. / Bandscheiben- und Wirbelkörpervolumenänderungen nach dorsaler Instrumentierung.

AIM: Even today, different opinions can be found concerning realignment loss of the adjoining intervertebral disc after fracture followed by dorsal fusion. There is still disagreement on intervertebral disc excision and the subsequent necessity of intercorporal fusion. METHOD: In this context, fractures of the thoracolumbar transition and its operative repair via instrumented bisegmental dorsal fusion at T11 - L1 and T12 - L2, respectively, have been examined. Immediately after the accident and after removal of the implant, sagittal MR images (T1-, TE-, T2-weighted) with a standard 4 mm slice thickness were made. Eighteen patients with fractures of the thoracolumbar transition (A3 and B1 according to the AO classification) could be included in this study. All fractures were of traumatic genesis. The implant was removed after an average of ten months. RESULTS: Allowing for planimetric measuring errors, our analysis generated a 14 % volume decrease of the upper and a 15 % volume decrease of the lower intervertebral disc. A volume change of 3 % in the bridged or fractured vertebral body was found to be without any verifiable significance. Tendentially, a slight volume loss of both adjacent intervertebral discs could be observed. CONCLUSION: In our opinion, the realignment loss after a mean ten months cannot be explained by the volume changes of the discs alone. The creeping of the intervertebral disc into the adjacent vertebral body accounts for the post-traumatic malalignment.

[Anterior spondylosis of the cervical spine causing dyspnea and sleep disturbance]. / Spondylophytäre Atem- und Schlafstörungen.

BACKGROUND: Cervical osteochondrosis is a rare differential diagnosis leading to dysphagia, inspiratory stridor and obstructive sleep apnea syndrome (OSAS). PATIENTS AND METHODS: We report six cases of patients with episodes of neck pain (n=6), pain reflected to the arm (n=1), sleep apnea (n=5), inspiratory stridor (n=3) and/or unclear dysphagia (n=6), who presented between 2000 and 2003 at the Römerwallklinik Mainz and the university hospitals of Mainz and Cologne. None of these patients had symptoms of spinal or radicular compression. All underwent otorhinolaryngological and radiological examination followed by excision of anterior spondylophytes and intervertebral fusion. One patient required immediate tracheotomy due to perforation of the pharyngeal wall associated with severe supraglottic swelling. RESULTS: All patients were free of inspiratory stridor postoperatively. Symptoms of dysphagia disappeared in four patients and were reduced in two. Three of five patients were free of apnea. OSAS had improved in two. Neck pain was eliminated in four cases and markedly improved in two cases. CONCLUSIONS: In case of symptoms of pharyngeal compression and OSAS, a vertebragenic cause should be considered.

Iatrogenic paraplegia in spinal surgery.

INTRODUCTION: Paraplegia as a result of a surgical spinal procedure is a rare complication. The risk cannot be precisely quantified due to the lack of current data. The aim of this study was to record a sufficiently large number of major spinal operations, especially extended methods in scoliosis surgery. Hereby, a reliable statement regarding the risk of severe neurological complications with these surgical techniques should be possible. First, a retrospective analysis of patients from a German spine centre (spinal fusion) and a survey of 17 German centres of spinal surgery were conducted for the retrospective acquisition of severe iatrogenic neurological complications. MATERIALS AND METHODS: The study included 1194 patients who underwent a spinal fusion during the period 1992-2002. The incidents of postoperative paraplegia are described in detail, and case studies done. Possible causes, methods of intraoperative monitoring and options of therapy are discussed according to research in relevant publications. Additionally, severe neurological complications of 3115 spinal operations were recorded in a standardised survey conducted throughout major German spinal centres. RESULTS: Of the 1194 patients surveyed, 7 (0.59%) experienced a postsurgical complete or incomplete paraplegia. In 3 of the recorded cases, the cause could be identified. The survey of 3115 scoliosis surgeries showed that iatrogenic paraplegia occurred with a frequency of 0.55%. The risks associated with short spinal fusions (0.14%), cervical discectomies (0.07%) and lumbar discectomies (0.03%) are considerably less. CONCLUSION: Operative treatment of scoliosis with a high degree of correction carries a risk of neurological complications of about 0.5%. Mechanical as well as ischaemic damage to the spinal cord can be detected early by means of consistent intraoperative neuromonitoring.

[Juxta-facet cysts as a differential diagnosis for lumbar neuralgia]. / Facettengelenkzysten als eine Differenzialdiagnose bei Lumboischialgien.

AIM: The aim of the current investigation it was to evaluate the incidence, clinical symptoms and the results of surgical treatment of lumbar juxta-facet cysts. METHOD: Between January 2002 and July 2003 305 patients underwent decompression of the lumbar spinal canal. In 3.6 % of these (n = 11) juxta-facet cyst were found to be responsible for the complaints and resection of the cyst was performed. All patients underwent standardized clinical examination and pain evaluation by the means of a visual analogue scale in a follow-up of 6.8 month on average. RESULTS: The average history of lumbar pain was 26 months, that of leg pain 23 weeks, respectively. Radicular symptoms appeared in 7 patients, and 9 of 11 patients complained about spinal claudication. Clinical examination showed a typical pain provocation during reclination of the lumbar spine. However none showed a segmental instability. Preoperative MRI revealed facet cysts with an average diameter of 9 mm (4-18 mm). All of the patients showed signs of degenerative spondylarthritis. Postoperative examination revealed in 8 cases a very good and in 2 cases a good result. One patient complained about persisting sciatica in spite of MR-tomographic demonstration of complete resection of the cyst. The walking-distance improved by least 50 % in 10 cases. Although no spinal fusion was performed, no patient developed a postoperative segmental instability. CONCLUSION: Juxta-facet cysts represent a not uncommon differential diagnosis in patients with lumbar radiculopathy. In the case of missing signs of segmental instability, resection of the cyst without simultaneous spinal fusion seems to be an appropriate therapy.

[Attachment points of the posterior longitudinal ligament and their importance for thoracic and lumbar spine fractures]. / Anheftungspunkte des Lig. longitudinale posterius und deren Bedeutung für Wirbelkörperfrakturen.

Spine fractures with damage of the posterior wall of the vertebra often can be anatomically reconstructed by indirect reduction. Whether the posterior longitudinal ligament (PLL) is responsible for the reduction is still subject to debate. The aim of our investigation was to ascertain the role of the PLL in closed reduction of spine fractures by identifying the bony attachment points of this ligament. We performed a gross anatomical dissection, a light- and polarized microscopic investigation on 22 human cadaverous thoracic and lumbar spines to determine the points of attachment of the PLL. We found two layers of the PLL. The superficial layer runs from the first thoracic down to the third lumbar vertebra with a width of 0.4-1.0 cm and from there descends as a thin rudiment to the sacrum. The deep layer shows a segmental rhomboid structure. Lateral fibers are attached to the annulus fibrosus and at the rim of the adjacent vertebrae. Medial fibers are attached additionally to the posterior wall of the vertebral bodies by bridging the foramina basivertebralia. Since these foramina become enlarged in the caudal parts of the vertebral column, the number of attachment points at the posterior wall of the vertebral bodies decreases caudally. Good results for reconstruction of the posterior wall in vertebral fractures of the thoracic and upper lumbar spine can be explained by the anatomical situation of the PLL and stress the important role of the PLL in indirect reduction of spine fractures.

[Total hip arthroplasty for metastatic Merkel cell carcinoma]. / Totalendoprothetischer Hüftgelenkersatz bei metastasiertem Merkel-Zellkarzinom.

Merkel cell carcinoma is an extremely rare malignant tumor which derives from the neuroendocrine cell system with features of epithelial differentiation. It belongs to the APUD-system (amine and precursor uptake and decarboxylation) and is characterized by highly aggressive spread with a predisposition for local recurrence and local regional and distant metastases. Metastatic spread to the hip has not been described in the literature before. We report on a 76-year old male patient with metastases of the left femoral head and greater trochanter 3 1/2 years after excision of a Merkel cell carcinoma of the left thigh with consecutive radical lymph node dissection of the left inguinal area and radiation therapy. Although microscopic,immunohistological and ultrastructural characteristics of the carcinoma have been well defined, there are no established treatment guidelines and prognostic factors that may predict the behaviour of the tumor due to the limited number of cases. Elective lymph node dissection decreases the rate of local recurrence but is not associated with improved overall survival. At the time of establishing the diagnosis, about half of the patients has positive lymph nodes with a 3-year-survival rate of 60%.

[Effect of design and implantation technique on risk of progressive sintering of various cervical vertebrae cages]. / Einfluss von Design und Implantationstechnik auf das Risiko der progredienten Sinterung verschiedener HWS-Cages.

The aim of this study was to compare the subsidence of differently designed cervical interbody fusion devices under defined conditions. Forty-five bovine vertebral bodies were dissected from soft tissue and cartilage. The bony end plate was then taken off by 0, 1, and 2 mm. Five vertebral bodies of each abrasion depth were prepared for the uptake of a fusion device. Thus, three different fusion devices of comparable size underwent biomechanic testing in a Zwick testing machine with 4000 cycles of axial compression between 50 and 1000 N. Every 1000 cycles, the subsidence into the vertebral body was measured. Abrasion of the end plate resulted in an increased subsidence. The cage with rectangular shape and the cage with cylindric body and lateral wings showed better resistance to axial compression as long as the end plate remained intact. When the end plate was taken off, the subsidence was as high as in the cylindric cage, of which the subsidence did not correlate to the end plate abrasion. During preparation of the implant bed, the cortical bone of the end plate must be treated carefully. In cases of intact end plate, rectangular supporting areas can decrease the risk of subsidence.

[Vertebral body stenting. A method for repositioning and augmenting vertebral compression fractures]. / Vertebral body stenting. Eine Methode zur Reposition und Augmentation von Wirbelkörperkompressionsfrakturen.

UNLABELLED: Purpose of the study was to demonstrate the effectiveness of expanding a fractured vertebral body by transpedicular dilatation and stenting. 7 human cadaveric vertebral bodies from L2 to L5 underwent axia compression until a vertebral burst fracture was provoked. Then, by bilateral transpedicular approach, balloon-catheters were introduced, which were armed with stents, usually used for angioplasty. The catheters were inflated with radiolucent fluid and the stents expanded under radiologic control. After expansion, the balloon was deflated and removed, the stents resting inside the vertebral body, holding their inflated shape. Then, the resulting hole was filled with an injectable biodegradable calcium-phosphate. CT-scans were performed after destruction and after expansion. Morphology before and after expansion was judged, using 3-D reconstructions. Vertebral body strength was measured before destruction and after treatment with an Instron testing machine. RESULTS: Vertebral body shape could be restored. Also impressed central parts of the bony endplate could be elevated by using a convergent approach through the pedicles. There was no collapse of the vertebral body after removing the catheter-balloons The vertebral body strength could be restored up to a physiologic level. This procedure gives new perspectives in the treatment either of osteoporotic compression or traumatic vertebral fracture. By using CT-guided technique, it could be performed by a minimally invasive approach percutaneously.

Traumatic intervertebral disc lesion--magnetic resonance imaging as a criterion for or against intervertebral fusion.

Lesions of the intervertebral disc accompanying vertebral fractures are the subject of controversy and discussion regarding the extent and manner of surgical intervention. The question of when to perform disc resection and intervertebral fusion, in particular, has not been answered satisfactorily. In order to evaluate short- and medium-term lesions of the discoligamentous complex associated with thoracolumbar burst fractures, magnetic resonance images made after stabilisation and again after implant removal were compared. Between 1997 and 1998, 20 patients who had suffered thoracolumbar burst fractures (AO classification A3 and B1 [26]) underwent posterior reduction and stabilisation using a Universal Spine System (USS, Synthes, Switzerland) titanium internal fixator. The implant was removed after an average of 10 months. Magnetic resonance imaging (MRI) scans were performed 1 week after both operations, allowing the changes in a total of 40 intervertebral discs adjacent to the fractured vertebral body to be investigated. The analysis was based on signal intensity of the intervertebral disc in T2-weighted scans and on morphological criteria. A total of 81% of the discs with initially normal T2-weighted signal showed the same signal after implant removal; 5 discs with initially increased signal intensity in T2-weighted scans normalised, 5 showed a decrease in intensity and 3 suffered a partial loss of signal. Among the 9 discs with initially decreased T2-weighted signal, only one had normalised by the time the implant was removed. A total of 86% of the 14 morphologically intact discs retained their structural integrity. Of the 25 discs with minor defects, only one could be considered as intact after implant removal, 15 remained the same and 9 deteriorated in structure. No disruption of the fibrous ring or of the posterior longitudinal ligament was observed, nor was there any prolapse of intervertebral discs. When the intervertebral disk is intact and has normal morphology and a normal T2-weighted MRI signal, resection or fusion of the fracture adjacent discs appears unjustified. In our opinion, the results do not support the possibility of predicting degradation in those discs that showed an altered T2-weighted signal after the first operation.

[Kyphotic deformation in fractures of the thoracic and lumbar spine]. / Kyphotische Deformierungen bei Frakturen der Brust- und Lendenwirbelsäule.

Kyphosis is the typical deformity of untreated spine fractures. In the majority of all injuries, destruction of the anterior part of the spine occurs. Biomechanical aspects require reconstruction of the anterior column. In 112 patients with a traumatic fracture of the thoracolumbar spine, a loss of correction in the sagittal plane exceeded the intraoperative correction. The cause of deterioration was in the main part the destruction of the intervertebral disk. The results of different surgical techniques are reviewed and discussed based on the literature. The dorsal instrumentation with or without autogenous bone grafting is not sufficient for spinal stabilization and kyphosis is the result. The golden standard for prevention of kyphosis is the combined approach with anterior cortical bone graft and posterior transpedicular screwing. In the case of anterior cage implantation, the risk of graft failure can be avoided. With anterior minimally invasive approaches, traumatization can be reduced by using the same biomechanical principles. In the case of a type A fracture with intact posterior elements, use of an anterior primary stable implant with bone graft represents an alternative method.

[Scoliosis and hip flexion contracture in Duchenne muscular dystrophy]. / Skoliose und Hüftbeugekontraktur bei Duchennescher Muskeldystrophie.

UNLABELLED: Spinal deformity is common in muscular dystrophy and usually occurs after loss of walking ability. Unlike in idiopathic and other scoliosis forms, there seems to be no side preference of the convexity. Aim of the study was to analyse, if there is any relation between incidence and extent of walking ability, lower limb contractures and development of scoliosis. METHODS: In a retrospective study, 45 patients with Duchenne muscular dystrophy who underwent surgery were analysed, concerning walking ability, contractures of lower extremities and scoliosis. RESULTS: 1: No scoliosis was observed in ambulatory patients. 2: 96% of the wheelchair bound patients suffered from scoliosis. 3: 96% of the scoliosis patients had hip flexion or abduction contractures. 4: In 12 of 15 cases with side-different contractures, scoliosis tended to the side with the greater contracture. CONCLUSIONS: The influence of hip contracture and pelvic obliquity on scoliosis is discussed controversially. Concerning muscular dystrophy, there seems to be a positive correlation between convexity and hip contracture. If this is a causal relation or if there is a faster progression of structural alteration of the muscles on one side has to be further investigated.

[Intraoperative hyperpyrexia in patients with osteogenesis imperfecta]. / Die intraoperative Hyperpyrexie bei Osteogenesis imperfecta-Betroffenen.

The aim of this study was to evaluate the influence of different types of anesthesia upon the intra- and postoperative body temperature in osteogenesis imperfecta patients. The development of an intraoperative hyperpyrexia of unknown origin is a typical phenomenon in patients with osteogenesis imperfecta. Body temperatures of up to 40 degrees C are known to complicate the operation. Therefore, in a retrospective study, the pre-, intra- and postoperative body temperature curves of 45 operations under different anaesthesias were measured. Group A underwent a common balanced anaesthesia with the volatile anaesthetic Enfluran in combination with Fentanyl, while group B was operated on under total intravenous anaesthesia (TIVA) with Propofol and Alfentanil. The preoperative temperatures were not different in the two groups. The intraoperative curves showed a constant body core temperature or even an increase under Enfluran, while the temperature always decreased under TIVA. This could be confirmed by intraindividual studies in 5 patients.

[Initial instability of different cages for fusion of the cervical spine]. / Die Primärstabilität unterschiedlicher Cages zur Fusion an der Halswirbelsäule.

Purpose of the present investigation is to determine the biomechanical behaviour of different cages for monosegmental fusion of the cervical spine. Three commercially available cages (BAK, NOVUS, WING) representing the different principles of intercorporal implants and a combination of intercorporal bone graft together with anterior plating were tested for their resistance and sintering patterns under axial compression conditions. Therefore, FSU (functional spine-units) of 5-months old calfs were used. After preparation, the anterior fusion was performed by an orthopaedic surgeon. Specimen were mounted in a testing machine Zwick 1425 and axial load from 100 N up to 2000 N was applied. The compressed distance was measured and put into relation to the applied load. After that, the device was unloaded and the test was repeated another 2 times to determine the plastic deformation of implant and specimen. There was no significant difference to all of the constructs in the first compression. After repeated compression, the WING-cage, the NOVUS-cage and the plate-construct showed a constant compression pattern as expression of resting stable on the vertebral endplates, whereas the cylindrical BAK-cage had a decrease in compression distance, but increase in sintering into the vertebral body. Intercorporal implants that require the destruction of the vertebral endplates as described in the Cloward dowel-technique may have a higher risk of sintering into the vertebral body and therefore of developing progressive kyphosis. By attaching lateral supporting areas this risk can be reduced and the advantage of sponges contact for fusion is preserved.

Orthopedic and neurosurgical treatment of severe kyphosis in myelomeningocele.

Kyphosis in myelomeningocele is characterized by a complex pattern of problems during development and therapy. On the one hand, decompensation of upright posture leads to loss of sitting ability and social integration; on the other hand, accompanying malformations and trophic alterations threaten the physical integrity and performance. Neurologic function, cerebrospinal fluid (CSF) circulation, skeletal deformity and the urinary transport system need to be kept in mind and need to be treated with cooperation between the different specialties. Especially during serious surgical interventions such as spinal surgery, neither the nervous system nor the kidneys must be ignored. Sixteen patients underwent kyphectomy in the Orthopedic Department of the University of Mainz between 1993 and 1997, all of them supervised by the Neurosurgical Department. In 13 cases, transversal myelotomy was performed. No insufficiency of CSF circulation was seen; neither were there any CSF fistulae. Particular problems arose from the skin and soft tissue above the gibbus, the lack of muscles and the regeneration deficiency caused by trophic disorders. Therefore, a significantly higher complication rate was found than with other correctional operations.

Sagittal static imbalance in myelomeningocele patients: improvement in sitting ability by partial and total gibbus resection.

The progression of kyphosis in myelomeningocele is independent of skeletal growth and requires early operative correction and stabilization to prevent a loss of sitting ability. In severe cases, only vertebrectomy makes it possible to achieve correction, stability and skin-closure without tension. In 14 patients with myelomeningocele gibbus, kyphectomy was performed, removing two vertebral bodies on average. The average kyphosis angle decreased from 128 degrees to 81 degrees, enabling most of the patients to participate again in social life by restoring wheelchair mobility. Nevertheless, a significantly higher complication rate was found compared to other correctional operations, lengthening the average hospital stay to 41 days. Special problems arose from trophic disorders of the skin and soft tissue and from the dystrophic muscles below the level of neural malfunction. In three cases, kyphosis reappeared cranial to the fused segments, requiring ventral stabilization. With respect to increasing kyphosis angle, an early intervention should be aimed at. A secondary operation can be necessary, if surgery is performed without taking care of the growth potential.