Fracture risk of vertebral bodies after cryosurgery using a miniature cryoprobe: A biomechanical in-vitro analysis on human bones

INTRODUCTION

Due to spinal instability and compressive neurologic deficits surgical management is sometimes necessary in patients with metastatic spinal lesions. However, in some cases open surgery is not possible and minimally invasive procedures, like cryoablation, are needed. The aim of the current study was to investigate whether a miniature cryoprobe provides adequate tissue cooling in vertebrae and to evaluate the direct impact of cryosurgery on vertebral body stability.

MATERIALS AND METHODS

Twelve thoracic vertebral bodies were harvested from fresh cadavers. After documenting bone density cryoablation was performed in six vertebral bodies according to a standardized procedure. Afterwards temperature inside the vertebral body and maximum breaking force were measured in the control and experimental groups.

RESULTS

Required temperature of -50° was reached in all areas. There was a significant correlation between maximum breaking force and measured bone density (p= 0.001). Mean breaking force within the experimental group was 5047 N (SD = 2955 N) compared to 4458 N (SD = 2554 N) in the control group. There were no observable differences in maximum breaking force between both groups.

CONCLUSION

Miniature cryoprobe can deliver adequate tissue cooling to -50°C in vertebral bodies. The procedure does not seem to influence breaking force of the treated bones in-vitro. Therefore, using miniature probes cryosurgery may provide a valuable alternative to conventional surgical resection of neoplastic diseases as well as of benign locally aggressive bone tumors.

Injuries in competitive boxing. A prospective study

Boxing remains a subject of controversy and is often classified as dangerous. But the discussion is based mostly on retrospective studies. This survey was conducted as a prospective study. From October 2012 to September 2013, 44 competitive boxers were asked to report their injuries once a month. The questionnaire collected general information (training, competition) and recorded the number of bouts fought, injuries and resulting lost days. A total of 192 injuries were recorded, 133 of which resulted in interruption of training or competition. Each boxer sustained 3 injuries per year on average. The injury rate was 12.8 injuries per 1 000 h of training. Boxers fighting more than 3 bouts per year sustain more injuries (p=0.0075). The injury rate does is not a function of age (age≤19 vs. > 19a, p=0.53). Injuries to the head and the upper limbs occur most frequently. The most common injuries are soft tissue lacerations and contusions. Head injuries with neurological symptoms rarely occur (4.2%). Boxing has a high injury rate that is comparable with other contact sports, but most injuries are minor. Injury frequency is not a function of whether the boxer competes in the junior or adult category. Athletes fighting many bouts per year have a greater risk of injury.

Injuries and overuse syndromes in competitive and elite bodybuilding

Competitive bodybuilding is a weightlifting sport similar to powerlifting, strongman competition and Olympic weightlifting, which aims to increase muscle mass, symmetry, and body definition. Although data regarding rates of injury, overuse syndromes and pain during routine training is available for these other disciplines, it is rare for competitive bodybuilding. The aim of this study was to investigate rates of injury, pain during workouts and/or overuse syndromes, as well as the influence of particular intrinsic and external factors. Data was collected using questionnaires from 71 competitive and elite bodybuilders. The information included training routines and prior injuries. Participants were recruited from bodybuilding clubs in Germany. 45.1% of athletes reported symptoms while training. The overall injury rate was computed to be 0.12 injuries per bodybuilder per year (0.24 injuries per 1 000 h of bodybuilding). Athletes over 40 exhibited higher rates of injury (p=0.029). Other investigated parameters showed no effects. Most injuries occurred in the shoulder, elbow, lumbar spine and knee regions. A large proportion of bodybuilders complained of pain not resulting in interruptions of training/competition. The injury rate is low compared to other weightlifting disciplines such as powerlifting, Olympic weightlifting or strongman competition. In comparison to team or contact sports the injury rate is minimal.

[Complication analysis of spinal interventions in adult central movement disorders and scoliosis]

BACKGROUND

Adult central movement disorders, malpostures, and scolioses can have their cause in various neurological underlying diseases such as Morbus Parkinson, Pisa syndrome, or segmental dystonia. Important clinical characteristics are marked postural distortions such as camptocormia (bent spine) or laterocollis. In cases of these adult scolioses, surgical spine treatment puts high demands on the surgeon. Surgery in Parkinson's disease, for example, is associated with serious surgery-specific as well as general complications. The more rarely occurring Pisa syndrome is an entity primarily requiring medical therapy.

PATIENTS AND METHODS

A series of ten case reports of patients with Morbus Parkinson and Pisa syndrome who underwent spinal surgery is presented and discussed. From these reports, treatment recommendations have been derived and complemented by references from the literature. An extensive MEDLINE search was performed for this purpose.

RESULTS AND CONCLUSION

In patients suffering from Parkinson's disease, even minor surgical interventions can lead to instability of whole spine segments or even the entire spine. Implant loosening, adjacent segment instability, general perioperative complications, and progressive malposture due to disease progress can bring forth disastrous treatment courses. Spinal fixation should be performed long-segmented in combination with ventral stabilisation. Due to osteoporosis, pedicle screw cement augmentation is recommended in this collective. If the diagnosis of Pisa syndrome is established, an optimised preoperative preparation should be initiated in close cooperation with neurologists. In many cases medical therapy is sufficient and surgical interventions can be avoided.

[Rotating physician in CHIR-Net. Evaluation of the curriculum]

BACKGROUND

Conduction of and participation in clinical trials is a major challenge for surgical departments especially as job performance in hospitals has increased immensely during the last few years due to economic aspects. Only 11.7 % of published clinical studies are randomized controlled trials. As more and more treatment procedures in medicine have an evidence-based design the aim must be to present randomized controlled trials with an evidence level 1 for an increasing number of surgical therapies. Since 2006 the German National Surgical Trial Network (CHIR-Net) has been established and funded by the Federal Ministry of Education and Research (BMBF) in order to promote the realization of clinical trials in surgery. Thus the basis for the execution of high quality clinical studies in surgery has been extended further. In the individual CHIR-Net centers clinical trials are planned, organized and supervised which requires extensive knowledge of prevalent international standards. Teaching them to rotating physicians is one of the tasks of CHIR-Net. Therefore, a special curriculum for physicians has been developed which is evaluated in this study.

MATERIALS AND METHODS

From December 2010 to March 2011 an online survey of physicians who had previously rotated in the CHIR-Net was conducted, starting from the Surgical Regional Center (CRZ) Witten-Herdecke/Cologne. A total of 19 partly open and partly closed questions concerning the person, training, duration of the rotation, the funding applied for and the generated scientific output were surveyed. In addition, the curriculum for physicians and rotation time was checked by means of 17 questions in an evaluation matrix.

RESULTS

In this article the results of the rotating physician evaluation are presented. The satisfaction of physicians with the training during the rotation is presented as well as an analysis of how many of the submitted publications were directly supported by CHIR-Net. It was also evaluated how many rotating physicians requested funding and what the type of funding was.

CONCLUSION

With the rotating physician model of CHIR-Net a working concept for the training of surgeons in clinical research and the realization of randomized surgical trials was established as a viable solution for the difficult situation of clinical research in the surgical disciplines with the double burden of research and clinical practice.

Ist eine Höhenrekonstruktion mit vergleichsweise wenig Zement für die Radiofrequenz-Kyphoplastie über einen monopedikulären Zugang möglich?

Hintergrund: Perkutane Zementaugmentationssysteme haben sich in den letzten 10 Jahren als eine effektive Behandlungsmethode bei Kompressionsfrakturen durchgesetzt. Als Sonderform ist nun seit 2009 die Radiofrequenz-Kyphoplastie (RF) hinzugekommen, die durch applizierbare Energie die Viskosität des Zements erhöht. Ziel dieser Studie war es, herauszufinden, ob mit einer vergleichsweise geringen Zementmenge eine Wirbelkörpererhöhung für osteoporotische Wirbelkörperfrakturen bei der RF-Kyphoplastie zu erreichen ist. Material und Methode: Bei diesem minimalinvasiven Verfahren wurde das „StabiliT® Vertebral Augmentation System“ der Firma DFine verwendet. Im Rahmen einer retrospektiven Studie wurden von 2011 bis Januar 2012 insgesamt 35 Patienten mit 49 osteoporotischen Wirbelkörperfrakturen versorgt. Als Parameter wurden die Altersstruktur mit Geschlechtsverteilung sowie klinisch der Verlauf der Schmerzintensität anhand der visuellen Analogskala (VAS0–100) ausgewertet. Radiologisch wurde die Wirbelkörpererhöhung (Vorder-, Hinterkante, mittlere Wirbelkörperhöhe und Kyphosewinkel) erfasst und mit dem applizierten Zementvolumen verglichen. Ergebnisse: Alle Patienten hatten vor der Operation eine gescheiterte konservative Behandlung mit weiterhin bestehenden Schmerzen auf Höhe des frakturierten Wirbelkörpers. Bis zur operativen Versorgung vergingen durchschnittlich 3,0 ± 1,3 Wochen. Die durchschnittliche VAS reduzierte sich signifikant von 71 ± 9,2 präoperativ auf 35 ± 6,2 postoperativ (p < 0,001) und nach 3 Monaten weiter auf 30 ± 5,7 (p < 0,001). Mit einem durchschnittlichen Zementvolumen von 2,9 ± 0,7 ml (1,8–4,1) im Thoralbereich und einem durchschnittlichen Zementvolumen von 3,0 ± 0,7 ml (2,0–5,0) im Lumbalbereich wurde eine statistisch signifikante Wirbelkörperaufrichtung erreicht. Die Vorderkante und die mittlere Wirbelkörperhöhe wurden signifikant um 2,3 mm und 3,1 mm angehoben, der Kyphosewinkel reduzierte sich ebenfalls signifikant um 2,1° nach 3 Monaten. Bei 2 Wirbelkörpern (4,1 %) zeigte sich ein minimaler Zementaustritt in die angrenzende Bandscheibe ohne klinische Konsequenz. Bei 2 Patienten entwickelten sich Anschlussfrakturen im kranialen Segment, die erneut mit einer RF-Kyphoplastie behandelt wurden. Schlussfolgerung: Mit einem durchschnittlichen Zementvolumen von 3 ml konnte mit der RF-Kyphoplastie eine schnelle und kurzfristige Besserung der Schmerzsymptomatik erreicht werden. Zusätzlich konnte mit diesem geringen Zementvolumen eine signifikante Wirbelkörperaufrichtung erzeugt werden. Es zeigte sich keine Korrelation zwischen der Wirbelkörperaufrichtung und dem klinischen Ergebnis. Mit der ermittelten Zementleckagenrate von 4,1 % gehört die Radiofrequenz-Kyphoplastie zu den sicheren und effektiven minimalinvasiven perkutanen Zementaugmentationsverfahren. Unsere Daten bestätigen die in der Literatur angegebene höhere Sicherheit für die Kyphoplastie im Vergleich zur Vertebroplastie.

[Severe airway distress following cervical spine operation: retrospective breakdown of the chain of errors]

A 71-year-old female patient received a prothesis due to a cervical disc prolapsed and bleeding into the collar soft tissues occurred postoperatively. Following a computed tomography examination severe peracute respiratory decompensation occurred while administering topical anesthesia to the pharynx in order to perform fiber optic intubation. Endotracheal intubation using conventional laryngoscopy was unsuccessful and the patient required immediate cricothyroidotomy. As an on-site cricothyrotomy set to establish a secure airway was not available the decision was taken to perform surgical cricothyroidotomy. As a conclusion to this life-threatening event in the case of symptoms, such as dyspnea, dysphonia and dysphagia after operations of the cervical spine the airway has to be secured early and according to the local algorithm.

[State of the art of lumbar intervertebral disc replacement]

Lumbar intervertebral total disc replacement is becoming more commonly employed for patients with degenerative disc disease as an alternative to spinal arthrodesis. Postulated advantages for the patients are motion preservation and height restoration in the affected segment, preventing adjacent level degeneration. Although studies show short and mid-term results which are comparable to spinal fusion, to date the long-term outcome is not clear. The different types of artificial discs and the current status of lumbar disc replacement are described.

The present role of vertebroplasty and kyphoplasty in the treatment of fresh vertebral compression fractures

Vertebroplasty (VP) and kyphoplasty (KP) are minimally invasive vertebral augmentation procedures for the treatment of fresh vertebral compression fractures (VCFs) associated with osteoporosis, trauma, malignant conditions, hemangiomas, and osteonecrosis. During these procedures, bone cement (e.g., polymethylmethacrylate) is percutaneously injected into the vertebral body. Systematic reviews of both procedures have shown significantly improved back pain and quality of life compared to conservative therapy. Direct comparison between VP and KP is not possible because of the lack of prospective randomized data comparing the two procedures. Both appear to improve patient functional status in most studies, although it is difficult to pool the available data because of differing measurement scales. With increasing popularity of both techniques, particularly over the past ten years, a rising number of publications have detailed potential complications secondary to cement extravasation, from compression of neural elements to venous embolism. Overall complication rates for both procedures are low. Systematic reviews have found significantly higher rates of cement leakage after VP (40%) versus KP (8%), with 3% of VP leaks being symptomatic. The evidence for increased risk of adjacent level fracture after these procedures compared to conservative treatment is inconclusive. When performed by a well-trained practitioner in appropriately selected patients, vertebroplasty and kyphoplasty are both safe and effective treatments for fresh vertebral compression fractures. Results from ongoing randomized controlled trials will provide further detailed information about both procedures in the future.

[Clinical research in orthopaedics--creation of a clinical trial unit in orthopaedics/trauma surgery]

AIM

The clinical trial is the link between research and medical practice and facilitates evidence-based therapies. There are specific difficulties to be faced when executing clinical trials related to surgical services (learning curve of the surgeon, blinding etc.). As a result, surgical randomised controlled clinical trials (RCT) are underrepresented in the total number of RCTs.

METHOD

To make it easier to implement surgical RCT, the Clinical Trial Unit for Orthopaedics and Trauma Surgery was established. Training of the supporting physicians was reached by rotations in the structures of CHIR-Net, a BMBF-funded network created to build up a region-wide surgical research infrastructure.

RESULT/CONCLUSION

Supported by the regional CHIR-Net Center and the regional Clinical Trial Center, a research institute was thus founded with the aim of contributing to a long-term improvement in clinical research in orthopaedics and trauma surgery.

[Spondylodiscitis - an interdisciplinary challenge]

HISTORY AND ADMISSION FINDINGS

A 21-year-old man presented with severe lumbar back pain and progressive paraparesis with clinical signs of spondylitis. Laboratory findings revealed elevated infectious parameters. Because of a positive Mantoux-Test he had been treated with quadruple tuberculostatic drugs for eight weeks without prior identification of the causative pathogen.

INVESTIGATIONS

Magnetic resonance imaging of the spine revealed a multisegmental spondylitis of the lumbar vertebrae (L3 - L5) with epidural empyema. Computed tomography (CT) of the abdomen confirmed large bilateral abscesses in the psoas muscles.

TREATMENT AND COURSE

The findings supported the diagnosis of spondylitis. The antibiotic regimen was continued. CT-guided drainage was placed in both psoas muscles. Laminectoma of L3 - 5 and dorsal spondylodesis of L2 - S1 were performed immediately. Mycobacterium tuberculosis was cultured from the intraoperative biopsies and treated according to the drug sensitivity test. After further surgical debridment and corporectomy of L4 and L5 the infection was successfully treated. Ten weeks after admission the patient was transferred to a neurologic rehabilitation unit for mobilization.

CONCLUSION

Spondylodiscitis treatment is complex and requires a multidisciplinary approach.

Stability changes after cryosurgery in long tubular bones in correlation to histological results: an animal trial

STUDY QUESTION

Pathologic bone fractures in cryosurgery of bone tumors have been described in literature. This study utilizing a sheep model should prove the possible reduction of potential fracture while using a new miniature cryoprobe minimizing tissue damage and providing accurate control of the ablation process. Furthermore, postoperative histological changes should be investigated and the results correlated with the stability trials.

METHODS

In 24 sheep, ablation of the femur and the tibial bone on one side was carried out. Ablation of the right femur was limited to an area of 2 cm(2) with single cortical bone, whereas at the left tibia the whole proximal tibial plateau was included. The other side served as a control entity without cryoablation. After a period of 2, 4, and 6 months postoperative investigation of bending resistance of the femoral bone and of compression resistance of the tibial bone as well as histological findings were done in eight animals each.

RESULTS

After 2 months there was a significant difference (P < 0.05) regarding compression resistance between the treated and the contralateral tibia, whereas the bending resistance in the treated femur was slightly lower than on the contralateral side. After 4 and 6 months the cryo-treated part showed a tendency towards weakness. Histological findings showed bone necrosis with slight beginning repair after 2 months. Four and six months later, bone necrosis still existed with increasing development of woven bone and conversion into lamellar bone.

DISCUSSION

A thorough control of the freezing process and the low iatrogenous weakening of the bone due to placing the probe when modern miniature cryoprobes are used can minimize the risk of pathological postoperative fractures. However, at least 2 months after operation there is histological proof of bone healing with appropriate reduction of bone stability, which should be considered for the clinical application of this new technique.

[The curriculum for rotation physicians within the CHIR-Net]

INTRODUCTION

CHIR-Net is a German national surgical network for clinical trials. It is supported by the Federal Ministry for Education and Research (BMBF 01GH0605) to establish infrastructure and expertise in the conduct of clinical trials within the surgical disciplines. An important aspect of this network is a qualified advanced training for physicians deployed at the CHIR-Net as part of a job rotation.

METHODS

A catalog of activities for the time of rotation within the network has been developed in cooperation with the CHIR-Net, the deployed physicians and cooperating regional clinical trials centers (ZKS/KKS).

RESULT

The focal points of the physicians' rotation in the CHIR-Net are outlined in a curriculum that has been established and evaluated in the network since January 2008.

CONCLUSION

After the rotation time at the CHIR-Net the skilled physicians act as multipliers of specialized knowledge on clinical research. In this way the acquired expertise will be transferred into clinical practice and treatment of patients within research projects will benefit directly.

Spondylodiscitis caused by Mycobacterium xenopi

The infection with non-tuberculous mycobacterium correlates highly with immunodeficiency. Mycobacterium xenopi (M. xenopi) is most commonly isolated in the respiratory tract, as a cause of endogenous spondylodiscitis it occurs but rarely. Only seven such cases have been reported in literature. In this paper, we present the case of an about 28-year-old HIV-positive patient with a long history of back pain. MRI of the spinal column and Positron Emission Tomography with (18)F-fluorodeoxyglucose as a tracer (F18-FDG-PET) confirmed the suspected spondylodiscitis. After performing a CT-controlled abscess drainage the patient's condition improved. Because of the severe destruction of the spinal segment concerned and because of the epidural abscess formation a vertebrectomy of T10 and surgical debridement of the paravertebral soft tissue via thoracotomy became urgently necessary. The spine was stabilized by interposing a cage and an anterolateral monobar system. M. xenopi could be proven by PCR out of the intraoperative specimen. After operation and antituberculotic therapy there was a fast convalescence. Diagnostics, therapy, and clinical outcome are discussed.