Functionalization of screw implants with superelastic structured Nitinol anchoring elements.

BACKGROUND: Demographic change is leading to an increase in the number of osteoporotic patients, so a rethink is required in implantology in order to be able to guarantee adequate anchoring stability in the bone. The functional modification of conventional standard screw implants using superelastic, structured Ti6Al4V anchoring elements promises great potential for increasing anchoring stability. METHODS: For this purpose, conventional screw implants were mechanically machined and extended so that structured-superelastic-positionable-Ti6Al4V anchoring elements could be used. The novel implants were investigated with three tests. The setup of the anchoring elements was investigated in CT studies in an artificial bone. In a subsequent simplified handling test, the handling of the functional samples was evaluated under surgical conditions. The anchorage stability compared to standard screw implants was investigated in a final pullout test according to ASTM F543-the international for the standard specification and test methods for metallic medical bone screws. RESULTS: The functionalization of conventional screw implants with structured superelastic Ti6Al4V anchoring elements is technically realizable. It was demonstrated that the anchoring elements can be set up in the artificial bone without any problems. The anchorage mechanism is easy to handle under operating conditions. The first simplified handling test showed that at the current point of the investigations, the anchoring elements have no negative influence on the surgical procedure (especially under the focus of screw implantation). Compared to conventional standard screws, more mechanical work is required to remove the functional patterns completely from the bone. CONCLUSION: In summary, it was shown that conventional standard screw implants can be functionalized with Ti6Al4V-structured NiTi anchoring elements and the new type of screws are suitable for orthopedic and neurosurgical use. A first biomechanical test showed that the anchoring stability could be increased by the anchoring elements.

Investigation into the Hybrid Production of a Superelastic Shape Memory Alloy with Additively Manufactured Structures for Medical Implants.

The demographic change in and the higher incidence of degenerative bone disease have resulted in an increase in the number of patients with osteoporotic bone tissue causing. amongst other issues, implant loosening. Revision surgery to treat and correct the loosenings should be avoided, because of the additional patient stress and high treatment costs. Shape memory alloys (SMA) can help to increase the anchorage stability of implants due to their superelastic behavior. The present study investigates the potential of hybridizing NiTi SMA sheets with additively manufactured Ti6Al4V anchoring structures using laser powder bed fusion (LPBF) technology to functionalize a pedicle screw. Different scanning strategies are evaluated, aiming for minimized warpage of the NiTi SMA sheet. For biomechanical tests, functional samples were manufactured. A good connection between the additively manufactured Ti6Al4V anchoring structures and NiTi SMA substrate could be observed though crack formation occurring at the transition area between the two materials. These cracks do not propagate during biomechanical testing, nor do they lead to flaking structures. In summary, the hybrid manufacturing of a NiTi SMA substrate with additively manufactured Ti6Al4V structures is suitable for medical implants.

Influence of curve morphology and location on the efficacy of rigid conservative treatment in patients with adolescent idiopathic scoliosis.

AIMS: The aim of the present study was to answer the question whether curve morphology and location have an influence on rigid conservative treatment in patients with adolescent idiopathic scoliosis (AIS). METHODS: We retrospectively analyzed AIS in 127 patients with single and double curves who had been treated with a Chêneau brace and physiotherapeutic specific exercises (B-PSE). The inclusion criteria were the presence of structural major curves ≥ 20° and < 50° (Risser stage 0 to 2) at the time when B-PSE was initiated. The patients were divided into two groups according to the outcome of treatment: failure (curve progression to ≥ 45° or surgery) and success (curve progression < 45° and no surgery). The main curve type (MCT), curve magnitude, and length (overall, above and below the apex), apical rotation, initial curve correction, flexibility, and derotation by the brace were compared between the two groups. RESULTS: In univariate analysis treatment failure depended significantly on: 1) MCT (p = 0.008); 2) the apical rotation of the major curve before (p = 0.007) and during brace treatment (p < 0.001); 3) the initial and in-brace Cobb angles of the major (p = 0.001 and p < 0.001, respectively) and minor curves (p = 0.015 and p = 0.002); 4) major curve flexibility (p = 0.005) and the in-brace curve correction rates (major p = 0.008, minor p = 0.034); and 5) the length of the major curve (LoC) above (p < 0.001) and below (p = 0.002) the apex. Furthermore, MCT (p = 0.043, p = 0.129, and p = 0.017 in MCT comparisons), LoC (upper length p = 0.003, lower length p = 0.005), and in-brace Cobb angles (major p = 0.002, minor p = 0.027) were significant in binary logistic regression analysis. CONCLUSION: Curve size, location, and morphology were found to influence the outcome of rigid conservative treatment of AIS. These findings may improve future brace design and patient selection for conservative treatment. Cite this article: Bone Joint J 2021;103-B(2):373-381.

Topography and evidence of a separate "fascia plate" for the femoral nerve inside the iliopsoas - A dorsal approach.

The femoral nerve stretch test is an essential part of clinical neurological examinations. This test is performed alongside Magnetic Resonance Imaging (MRI) to determine if there is any evidence of nerve root irritation, usually as a consequence of disc prolapse. The test occasionally gives false positive results. Why such false positives can occur, is subject to continued research, however, no obvious reason has yet emerged. We hypothesize that connectives of the femoral nerve may explain such a phenomenon. To see these connectives, we approached the femoral nerve from dorsal in 12 cases. With the use of ink injection into the subparaneural compartment of the femoral nerve and dissections, a thin transparent structure can clearly be seen that is separate from the epineurium, perineurium, and a paraneural sheath. A continuation of the paraneural sheath produces a fascia plate approximately 1.5 cm in width and with a thickness of around 3 mm, which not only circumnavigates the nerve but projects into the surrounding tissues. Our qualitative observations show that not only does this femoral nerve fascia plate exists, but it also contains nerves and vessels. Furthermore, we show that the femoral nerve is connected to the myofascial complex of the iliopsoas, and in a separate fascia plate from the iliopsoas fascia. This plate is a hitherto neglected connective which extends as far as the spinal dura mater. Evidence from our plastinates and histological sections suggests that when tension is applied to the femoral nerve during the femoral nerve stretch test, tension is also applied to the femoral nerve fascia plate. The femoral nerve fascia plate could be a specific factor that contributes to pain resulting in a false positive femoral nerve stretch test.

Biological Cell Investigation of Structured Nitinol Surfaces for the Functionalization of Implants.

Expandable implants including shape memory alloy (SMA) elements have great potential to minimize the risk of implant loosening and to increase the primary stability of bone anchoring. Surface structuring of such elements may further improve these properties and support osteointegration and bone healing. In this given study, SMA sheets were processed by deploying additive and removal manufacturing technologies for 3D-printed surgical implants. The additive technology was realized by applying a new laser beam melting technology to print titanium structures on the SMA sheets. The removal step was realized as a standard process with an ultrashort-pulse laser. The morphology, metabolic activity, and mineralization patterns of human bone marrow stromal cells were examined to evaluate the biocompatibility of the new surface structures. It was shown that both surface structures support cell adhesion and the formation of a cytoskeleton. The examination of the metabolic activity of the marrow stromal cells on the samples showed that the number of cells on the laser-structured samples was lower when compared to the 3D-printed ones. The calcium phosphate accumulation, which was used to examine the mineralization of marrow stromal cells, was higher in the laser-structured samples than in the 3D-printed ones. These results indicate that the additive- and laser-structured SAM sheets seem biocompatible and that the macrostructure surface and manufacturing technology may have positive influences on the behavior of the bone formation. The use of the new additive technique and the resulting macrostructures seems to be a promising approach to combine increased anchorage stability with simultaneously enhanced osteointegration.

On the importance of the innervation of the human cervical longitudinal ligaments at vertebral level.

PURPOSE: In our aging society, the prevalence of degenerative spinal diseases rose drastically within the last years. However, up till now, the origin of cervical pain is incompletely understood. While animal and small cadaver studies indicate that a complex system of sensory and nociceptive nerve fibers in the anterior (ALL) and posterior longitudinal ligament (PLL) at the level of the intervertebral disc might be involved, there is a lack of data exploring whether such a network exists and is equally distributed within the cervical vertebrae (VB). We, therefore, aimed to investigate the spatial distribution of the mentioned nerve networks in human tissue. METHODS: We performed macroscopic (Sihler staining, Spalteholz technique, and Plastination) and microscopic (immunohistochemistry for PGP 9.5 and CGRP) studies to characterize spatial differences in sensory and nociceptive innervation patterns. Therefore, 23 human body donors were dissected from level C3-C6. RESULTS: We could show that there is a focal increase in sensory and nociceptive nerve fibers at the level of C4 and C5 for both ALL and PLL, while we observed less nerve fiber density at the level of C3 and C6. An anatomical vicinity between nerve and vessels was observed. CONCLUSION: To our knowledge, these findings for the first time report spatial differences in sensory and nociceptive nerve fibers in the human cervical spine at VB level. The interconnection between nerves and vessels supports the importance of the perivascular plexus. These findings might be of special interest for clinical practice as many patients suffer from pain after cervical spine surgery.

Experimental validation of adaptive pedicle screws-a novel implant concept using shape memory alloys.

Pedicle screw fixation is a standard procedure in spine surgery. A secure anchoring in deficient (e.g., osteoporotic) bone or in a secondary supply after a revision is a major challenge. This study aimed to test the primary stability of a new self-expanding shape memory actuator screw concept with the traditional screw design. The actuator part braces itself against the osseous environment after implantation by heating to body temperature. Thirty screws and twenty-four actuator sheets were manufactured and tested in vertebrae from seven human cadavers in vitro. The pullout force and mechanical work for the pullout were evaluated. Bone quality was determined from µCT. The mean actuator sheet compression force of the used shape memory alloy (SMA) sheets averaged - 8.2 ± 0.6 N. Seven of the SMA screws activated correctly after the implantation, four activated unilaterally only. The pullout force averaged 868 ± 392 N for the standard screws and 828 ± 353 N for the SMA screws. The mechanical work was conducted after the first 100 N, and the loss of strain resistance of 40% of the pullout force averaged 2.2 ± 1.6 Nm for the standard screws, and 1.7 ± 0.9 Nm for the SMA screws. Consequently, the novel concept showed non-inferiority compared with the traditional screw designs. Graphical abstract.

Psychosocial Stress Reactivity as Predictor of Operative Outcome in Lumbar Disc Surgery.

BACKGROUND: A large proportion of the population suffers from chronic back pain. For optimal treatment, the question arises which patients would benefit from conservative therapy and for whom lumbar disc surgery is most appropriate. It seems reasonable to analyze the impact of paraclinical parameters on the operation outcome to identify patients who would benefit less from surgery or need special pre-/postoperative medical care. MATERIALS AND METHODS: From March 2012 to July 2014, 32 patients were treated via microscopically supported interlaminar fenestration and discectomy at the Department of Neurosurgery, University Hospital Carl Gustav Carus Dresden. One day before the operation, a cortisol survey was made during the stress response of the Trier Social Stress Test. At the same time, a survey of relevant questionnaires was conducted by which the postoperative symptom experience was made operational and comparable with the evaluation of the same information thirty days afterwards. RESULTS: It could be shown that there is a connection between cortisol reactivity and the pain burden following operations. Patients with a greater cortisol reaction under stress exposition partially experienced more intense postoperative pain than the patients with a lower cortisol reaction. However, this relationship could only be explained by single significant results, whereas further calculations could not produce any significance. CONCLUSIONS: Cortisol reactivity seems to be associated with pain development. The inconsistent findings in empiricism as well as in this investigation are indicative of a complex association of postoperative pain and cortisol reactivity, which needs to be examined further.

The Importance of Surgery as Part of Multimodal Therapy in Rapid Progressive Primary Extraosseous Ewing Sarcoma of the Cervical Intra- and Epidural Space.

Primary extraosseous Ewing sarcomas (EESs) are an extremely rare pathological entity. Less than 32 cases have been reported in the literature. Here we report an uncommon case with very rapid progression in the cervical region with extra- and intradural involvement. We present a thorough review of the literature and discuss possible treatment modalities. The Medline database was searched using the search terms: Ewing sarcoma, extraosseus tumour, treatment, management, cervical spine. A previously healthy 29-year-old man complained of right-sided radiculopathy (C7). Magnetic resonance imaging showed an enhancing foraminal, sandglass shaped neurinoma-like lesion. Surgery revealed an intraand extra-dural lesion, which was histologically diagnosed as Ewing sarcoma. Despite gross total resection, there was a massive symptomatic tumor recurrence within 6 weeks. A second gross total resection was realized. The patient was treated according to the EURO E.W.I.N.G.-Protocol (VIDE) and recovered very well (progression-free interval during therapy). Several decompressive re-surgeries were realized with adjuvant radio-chemotherapy. At the last follow-up (17 months after initial surgery) the patient was in remission with a good quality of live. This case is to illustrate that despite extensive therapeutic efforts, the progression-free survival in case of primary EES may be very short. To maintain neurological function and good quality of live as long as possible, a multimodal strategy seems to be adequate. Like in the present case this implies several surgeries and adjuvant chemo-and radiotherapy. Whether this improves overall survival remains unclear.

The diagnostic value of midbrain hyperechogenicity in ALS is limited for discriminating key ALS differential diagnoses.

BACKGROUND: Hyperechogenicity of the substantia nigra was recently reported in patients with sporadic ALS with a frequency similar to PD. Data on the diagnostic utility compared to key differential diagnoses of ALS do not exist yet. METHODS: We prospectively enrolled 43 patients with ALS, 29 with myasthenia gravis, 25 patients with inflammatory neuropathy, and 13 with cervical canal stenosis. All patients were examined by a blinded investigator using transcranial B-mode sonography planimetrically measuring hyperechogenic areas of the midbrain representing the substantia nigra. RESULTS: Mean midbrain hyperechogenic area was increased in ALS compared to non-ALS differentials. ROC analysis revealed only small area under the curve for detecting ALS (AUC: 0.669 [95%CI: 0.56-0.78]; p = 0.006). Highest Youden index was observed for area size of <0.14 cm(2) (Youden index: 0.28). Using this cut-off score and that generated from normative data of healthy controls, area size measurements provided a sensitivity of only 46-58% and specificity of 69-83% for detecting ALS. No correlations of hyperechogenic area sizes in ALS patients were found to age, gender, ALS subtype (bulbar versus spinal form), disease duration or ALS-FRS-R score. CONCLUSIONS: Midbrain hyperechogenicity is reproducibly found in ALS patients, but its diagnostic value for discriminating ALS from its key differentials is limited.

VolHOG: a volumetric object recognition approach based on bivariate histograms of oriented gradients for vertebra detection in cervical spine MRI.

PURPOSE: The automatic recognition of vertebrae in volumetric images is an important step toward automatic spinal diagnosis and therapy support systems. There are many applications such as the detection of pathologies and segmentation which would benefit from automatic initialization by the detection of vertebrae. One possible application is the initialization of local vertebral segmentation methods, eliminating the need for manual initialization by a human operator. Automating the initialization process would optimize the clinical workflow. However, automatic vertebra recognition in magnetic resonance (MR) images is a challenging task due to noise in images, pathological deformations of the spine, and image contrast variations. METHODS: This work presents a fully automatic algorithm for 3D cervical vertebra detection in MR images. We propose a machine learning method for cervical vertebra detection based on new features combined with a linear support vector machine for classification. An algorithm for bivariate gradient orientation histogram generation from three-dimensional raster image data is introduced which allows us to describe three-dimensional objects using the authors' proposed bivariate histograms. RESULTS: A detailed performance evaluation on 21 T2-weighted MR images of the cervical vertebral region is given. A single model for cervical vertebrae C3-C7 is generated and evaluated. The results show that the generic model performs equally well for each of the cervical vertebrae C3-C7. The algorithm's performance is also evaluated on images containing various levels of artificial noise. The results indicate that the proposed algorithm achieves good results despite the presence of severe image noise. CONCLUSIONS: The proposed detection method delivers accurate locations of cervical vertebrae in MR images which can be used in diagnosis and therapy. In order to achieve absolute comparability with the results of future work, the authors are following an open data approach by making the image dataset used in their performance evaluation available to the public.

Percutaneous pedicle screw and rod fixation with TLIF in a series of 14 patients with recurrent lumbar disc herniation.

PURPOSE: To determine if minimally invasive transforaminal lumbar interbody fusion (TLIF) using the Medtronic Sextant system is a reliable surgical treatment option in patients with recurrent lumbar disc herniation, compared with the traditional open procedure. PATIENTS AND METHODS: Clinical and radiographic data were retrospectively collected from a total of 33 patients who underwent single level lumbar fusion between 2007 and 2010. 14 underwent minimally invasive TLIF using the Sextant system, and the other 19 patients underwent the open procedure. All patients suffered from at least first recurrent lumbar disc herniation, and additionally from disc degeneration associated with erosive chondrosis Modic grade I-II due to previous surgical, non-instrumental interventions. RESULTS: Median operation time in the minimally invasive group was 140 min (95-190); average X-ray exposure time: 2.35 min (1.5-3.5); median postoperative resting time in hospital: 5 days (3-7). Postoperative pain relief and mobility improvement were documented with the visual analogue scale (6.9-3.0) and the Oswestry Disability Index (6.8-2.4). All patients benefited from surgery at follow up. These data were on many terms significantly superior compared with data of patients in the open surgery group. CONCLUSION: Percutaneous minimally invasive TLIF technique with the Medtronic Sextant system is a gentle, tissue protecting and safe alternative procedure for lumbar fusion in patients with recurrent lumbar disc herniation and erosive chondrosis.

An extremely rare, remote intracerebral metastasis of oral cavity cancer: a case report.

Distant brain metastases from oral squamous cell carcinomas (OSCC) are extremely rare. Here we describe a case of a 53-year-old man with a primary OSCC who referred to the neurosurgical department because of epileptic seizures. MR imaging revealed an enhancing lesion in the right parietal lobe. A craniotomy with tumor removing was performed. Histopathological examination verified an invasive, minimally differentiated metastasis of the primary OSCC. The patient refused whole brain radiation therapy and died from pulmonary metastatic disease 10 months after the neurosurgical intervention without any cerebral recurrence. To the authors' knowledge, only two similar cases have been previously reported.

Surgery of recurrent brain metastases: retrospective analysis of 67 patients.

OBJECTIVE: Treatment of patients with recurrent brain metastasis is one of the major challenges in neurooncology. Commonly, WBRT was applied after or as the initial treatment. Many patients received radiosurgery or their lesions were operated on. The question arises of what treatment modalities are appropriate and can be offered to the patients. In our retrospective analysis, we evaluated whether re-operation might be a useful measurement for the patients with respect to overall survival and quality of life. METHODS: We included 67 patients who were treated between 1993 and 2008 in our department. The median age was 59 years. Metastases of 11 different primaries were diagnosed. The median OST was 7.5 months. RESULTS: Statistically significant prognostic factors for OS were single lesions, completeness of resection, and time to recurrence, which was significantly influenced by WBRT after first operation. The one year survival rate correlated with the RPA classification: class I: 53.3 %, class II: 26.9 %, class III: 12.5 %. In 31.3 %, a second recurrence occurred which was treated by repeated surgery. Six patients survived as long-term survivors (25.7-132.2 months). CONCLUSION: Surgery of recurrent brain metastasis is an important therapeutic option. A subgroup of patients, defined by prognostic factors, will profit with improvement of symptoms and prolongation of the overall survival time. Even long-term survivors can be expected.

Atypical Central Neurocytoma with Recurrent Spinal Dissemination over a Period of 20 Years: A Case Report and Review of the Literature.

We present an unusual case of a late recurrent central neurocytoma that was rediagnosed as an ependymoma and neurocytoma in accordance with changes in histological classifications. Case Description. A 56-year-old male teacher presented with incomplete transverse syndrome due to several intradural extramedullary tumors at the level of lumbar vertebrae 1-3. The histological diagnosis at the time was atypical ependymoma. One year later, two additional tumors were removed at the L5-S1 vertebral level. For 12 years, the patient remained tumor free on followup. Fourteen years after the initial diagnosis, the patient presented with thoracic paresthesias due to two new extramedullary tumors in the C7-T1 and the T8-T9 vertebral levels. After complete removal of the tumors, a radiological survey revealed an intracranial lesion in the third ventricle. Five months later, an additional lesion recurrence was removed surgically. The most recent histological diagnosis revealed an atypical central neurocytoma. In retrospect, the previous tumors were reclassified as neurocytoma according to the additional immunohistochemistry evidence. Discussion. There is no standard adjuvant treatment regimen for atypical neurocytoma; therefore, the patient is currently under close followup. Modern histopathological diagnosis is essential in these cases. Potential routes for dissemination of the tumor should be considered upon first recurrence.

Width of the cervical intervertebral neuroforamina after total disc replacement with the Cerkinetic prosthesis: a three-dimensional simulation using a computer-aided design model.

INTRODUCTION: Physiological cervical intervertebral motion inherently induces a neuroforaminal volume change. Integration of an artificial motion component within this intervertebral kinematic system may cause neuroforamina to lose their ability for continuous and instantaneous volume adaptation, inducing foraminal stenosis. The purpose of the current study is to virtually simulate a newly developed cervical total disc replacement (TDR) to evaluate the neuroforaminal dimensions at rest and during motion. MATERIALS AND METHODS: In a three-dimensional computer-aided design model of the spine, the Cerkinetic (OrthoKinematica Ltd., Haifa, Israel) TDR was virtually implanted at the C5-C6 disc space. The TDR consists of a bearing mechanism with an elliptical protuberance and a recess, allowing a progressive increase of the intervertebral axial spacing in all three dimensions and in line with flexion and extension. Translations are performed in accordance with the physiological forces influencing the disc space and spinal continuum. The minimal proximal neuroforaminal width was defined and evaluated at rest and motion. RESULTS: A progressive increase (15.2% at 6 degrees) in flexion and a decrease (12.3% at 6 degrees) in extension of the neuroforaminal width were observed. With axial motion, a progressive increase (44.6% at 6 degrees) of the right neuroforamen width as well as a decrease of the left neuroforamen width (15.3% at 6 degrees) were seen. CONCLUSION: The TDR under investigation simulates the intervertebral kinematics, allowing a physiological adjustment of the facet joints in rest and motion. This preserves the ability of the neuroforamina to maintain their capability of changing their dimensions.

Retrospective study of 127 surgically treated patients with multiple brain metastases: indication, prognostic factors, and outcome.

BACKGROUND: Metastases are the most frequent tumours in the brain. At the time of diagnosis, more than 50% of patients present with multiple lesions. The goal of our retrospective investigation was to evaluate the outcome of patients who undergo surgery for multiple cerebral metastases and to determine prognostic factors. METHODS: We included 127 patients with multiple brain metastases in the study. The median number of metastases was three. All patients were operated on for at least one lesion. The indications for surgery were: large tumours ≥27 cm(3), metastases of unknown primaries at the time of diagnosis, and space-occupying cerebellar lesions. If possible, adjuvant WBRT was applied. RESULTS: The median MST of the whole group was 6.5 months; for patients with complete resection, 10.6 months. According to the RPA classification the MST ranged between 19.4 (class I), 7.8 (class II), and 3.4 months (class III) (p < 0.001). KPS > 70 had a significant influence on MST (9.1 months vs. 3.4 months, p < 0.001), the number of lesions: 2-4 vs. >4 (p = 0.046), and postoperative WBRT in multivariate analysis (p = 0.026). Age was not a significant factor. The 2-year survival rate was 15% and the 3-year survival rate 10%. CONCLUSIONS: Favourable factors for prolonged survival were complete resection of all lesions, no more than four metastases, RPA-class I and adjuvant WBRT. The resection of large lesions, while leaving smaller residual ones, did not result in increased survival.

A newly developed drill with a polished tip for the anterior cervical approach in spinal canal stenosis: a technical note.

PURPOSE: The goal of our efforts was to develop a modified drill that allows a safe milling of the dorsal osteophytes located close to the dura. METHODS: Usually a normal high-speed drill is used for the resection of uncarthrotic and spondylophytic bone. In one patient, we used our new high-speed drill close to the dura in an area, which is not easy reachable with a normal drill or a rongeur. RESULTS: Employing the new drill with a polished tip, the spine surgeon is able to overcome the anatomical restrictions, which he has to face when the anterior approach to the cervical spine. The resection of dorsal osteophytes is easy and safe. CONCLUSION: The newly developed drill with the polished tip is a safe and high-quality alternative to conventional drills. Further investigations have to be done, to proof the advantages of the new drill.

Operative management of a non-traumatic cervico-thoracic spondylolisthesis: a case report.

INTRODUCTION: In contrast to spondylolisthesis of the lumbar spine, non-traumatic cervico-thoracic spondylolisthesis is a very rare lesion. Even minor changes in the displacement of the vertebrae or the cord can lead to cervical myelopathy and paralysis. Since only a few cases have been well-documented, there is currently no clear preference between operative techniques. CASE PRESENTATION: We describe the case of a 63-year-old Caucasian man with a 13 mm spondylolisthesis between C7 and T1. Within a few months, a progressive cervical myelopathy developed as he began to suffer pain and loss of function of his digits and was no longer able to walk unassisted. In an interdisciplinary collaboration between neurological and orthopedic surgeons, a ventral-dorsal-ventral approach was performed on one vertebral section. The ventral removal of the intervertebral disc was followed by laminectomy and dorsal instrumentation. A new application technique was established by inserting bicortical screws into the transverse processes of T2 and T3. The structure was subsequently stabilized by the ventral insertion of a Harms basket. The procedure was successful as it halted progression of the myelopathy. The patient demonstrated improved sensitivity and recovered the ability to walk unassisted. He has now been able to walk unassisted for two years postoperatively. CONCLUSION: This paper describes a successful treatment for a very rare case of cervico-thoracic spondylolisthesis. The technique of inserting bicortical screws into the transverse processes is a fast, safe and successful method that does not require the use of intraoperative radiographs for placement of the bicortical screws into the transverse processes.

Olfactory bulb volume in patients with idiopathic normal pressure hydrocephalus.

INTRODUCTION: An important pathological feature of idiopathic normal pressure hydrocephalus (iNPH) is a dysfunction of cerebrospinal fluid dynamics. Considering the delicate olfactory structures it appears possible that the olfactory bulb (OB) is compromised by this disease. Reports on the anatomy of the olfactory bulb and smell function in patients with idiopathic normal pressure hydrocephalus are absent in the literature. The main purpose of the present study was to evaluate the olfactory bulb (OB) volume and smell function in iNPH. METHODS: The study comprised 17 patients with iNPH (seven women and ten men, mean age = 66 years); they were compared to a group of 24 healthy people (11 women and 13 men, mean age = 62 years). Comprehensive assessment of olfactory function was conducted with the "Sniffin' Sticks" test kit. In an additional pilot study, in a small subgroup of eight patients, measurements were performed before and approximately 7 months after surgical treatment of the hydrocephalus. RESULTS: The OB volume in patients with iNPH was significantly smaller compared to healthy controls. In our small postoperative patient population (n = 8), there was no significant change of the OB volume. CONCLUSION: In conclusion our results suggest that iNPH significantly affects OB volumes.