Timmo Koy

The reliability of clinical examination in detecting pelvic fractures in blunt trauma patients: a meta-analysis.

IntroductionSeveral studies have recently questioned whether routine radiographic screening for pelvic fractures is necessary in the initial evaluation of blunt trauma patients. Therefore, we assessed how sensitive and specific the clinical examination is in detecting fractures of the pelvis.MethodsWe extensively searched various medical databases for studies that reported on the accuracy of pelvic examination in severely injured adults or children. Individual study results were summarized in a receiver operating characteristics (ROC) curve and pooled in a meta-analysis.ResultsTwelve studies with a total of 5454 patients met our inclusion criteria and provided data in sufficient detail. Pooled sensitivity and specificity were 0.90 (95% confidence interval: 0.85–0.93) and 0.90 (0.84–0.94), respectively. Results were better in those studies which excluded neurologically impaired patients [e.g., Glasgow Coma Scale (GCS) <13]. Among the 49 false negative cases whose fractures went undetected on clinical examination, the majority of patients had either altered consciousness or minor pelvic fracture only. Only 3 clinically relevant pelvic fractures were missed among 441 patients with fracture within a total population of 5235 patients.ConclusionIn stable and alert trauma patients, a thorough clinical examination will detect pelvic fractures with nearly 100% sensitivity, thus rendering initial radiography unnecessary in this group of patients.

Torsion and Antero-Posterior Bending in the In Vivo Human Tibia Loading Regimes during Walking and Running

Bending, in addition to compression, is recognized to be a common loading pattern in long bones in animals. However, due to the technical difficulty of measuring bone deformation in humans, our current understanding of bone loading patterns in humans is very limited. In the present study, we hypothesized that bending and torsion are important loading regimes in the human tibia. In vivo tibia segment deformation in humans was assessed during walking and running utilizing a novel optical approach. Results suggest that the proximal tibia primarily bends to the posterior (bending angle: 0.15°–1.30°) and medial aspect (bending angle: 0.38°–0.90°) and that it twists externally (torsion angle: 0.67°–1.66°) in relation to the distal tibia during the stance phase of overground walking at a speed between 2.5 and 6.1 km/h. Peak posterior bending and peak torsion occurred during the first and second half of stance phase, respectively. The peak-to-peak antero-posterior (AP) bending angles increased linearly with vertical ground reaction force and speed. Similarly, peak-to-peak torsion angles increased with the vertical free moment in four of the five test subjects and with the speed in three of the test subjects. There was no correlation between peak-to-peak medio-lateral (ML) bending angles and ground reaction force or speed. On the treadmill, peak-to-peak AP bending angles increased with walking and running speed, but peak-to-peak torsion angles and peak-to-peak ML bending angles remained constant during walking. Peak-to-peak AP bending angle during treadmill running was speed-dependent and larger than that observed during walking. In contrast, peak-to-peak tibia torsion angle was smaller during treadmill running than during walking. To conclude, bending and torsion of substantial magnitude were observed in the human tibia during walking and running. A systematic distribution of peak amplitude was found during the first and second parts of the stance phase.

Clinical Outcomes and Quality of Life 1 Year after Open Microsurgical Decompression or Implantation of an Interspinous Stand-Alone Spacer

BACKGROUND Interspinous stand-alone implants are inserted without open decompression to treat symptomatic lumbar spinal stenosis (LSS). The insertion procedure is technically simple, low-risk, and quick. However, the question remains whether the resulting clinical outcomes compare with those of microsurgical decompression, the gold standard. MATERIAL AND METHODS This prospective, comparative study included all patients (n=36) with neurogenic intermittent claudication (NIC) secondary to LSS with symptoms improving in forward flexion treated operatively with either interspinous stand-alone spacer insertion (Aperius (®); Medtronic, Tolochenaz, Switzerland) (group 1) or microsurgical bilateral operative decompression (group 2) between February 2007 and November 2008. Data (patient data, operative data, COMI, SF-36 PCS and MCS, ODI, and walking tolerance) were collected preoperatively as well as at 6 weeks, at 3, 6, and 9 months, and at one year follow-up (FU). All patients had complete FU over 1 year. RESULTS Compared to preoperative measurements, surgery led to improvements of all parameters in the entire collective as well as both individual groups. There were no statistically relevant differences between the 2 groups over the entire course of FU. However, improvements in the ODI and SF-36 MCS were not significant in group 1, in contrast to those of group 2. Also, although in group 1 the improvements in leg pain (VAS leg) were still significant (p<0.05) at 6 months, this was no longer the case at 1 year FU. In group 1 at 1 year FU an increase in leg pain was observed, while in group 2,  minimal improvements continued. Walking tolerance was significantly improved at all FU times compared to preoperatively, regardless of group (p<0.01). At no time there was a significant difference between the groups. In group 1, admission and operative times were shorter and blood loss decreased. The complication rate was 0% in group 1 and 20% in group 2, however reoperation was required by 27.3% of group 1 patients and 0% of group 2. CONCLUSION Implantation of an interspinous stand-alone spacer yields clinical success comparable to open decompression, at least within the first year of FU. The 1-year conversion rate of 27.3% is, however, decidedly too high.

On the relationship between tibia torsional deformation and regional muscle contractions in habitual human exercises in vivo

The mechanical relationship between bone and muscle has been long recognized. However, it still remains unclear how muscles exactly load on bone. In this study, utilizing an optical segment tracking technique, the in vivo tibia loading regimes in terms of tibia segment deformation in humans were investigated during walking, forefoot and rear foot stair ascent and running and isometric plantar flexion. Results suggested that the proximal tibia primarily bends to the posterior aspect and twists to the external aspect with respect to the distal tibia. During walking, peak posterior bending and peak torsion occurred in the first half (22%) and second half (76%) of the stance phase, respectively. During stair ascent, two noticeable peaks of torsion were found with forefoot strike (38% and 82% of stance phase), but only one peak of torsion was found with rear foot strike (78% of stance phase). The torsional deformation angle during both stair ascent and running was larger with forefoot strike than rear foot strike. During isometric plantar flexion, the tibia deformation regimes were characterized more by torsion (maximum 1.35°) than bending (maximum 0.52°). To conclude, bending and torsion predominated the tibia loading regimes during the investigated activities. Tibia torsional deformation is closely related to calf muscle contractions, which further confirm the notion of the muscle-bone mechanical link and shift the focus from loading magnitude to loading regimes in bone mechanobiology. It thus is speculated that torsion is another, yet under-rated factor, besides the compression and tension, to drive long bone mechano-adaptation.

Komplikationsanalyse von spinalen Eingriffen bei adulten zentralen Bewegungsstörungen und Skoliosen

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 Parkinsons 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 Parkinsons 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.

Indications and contraindications: interspinous process decompression devices in lumbar spine surgery.

BACKGROUND Interspinous process decompression devices (IPD) allow a minimally invasive treatment of lumbar spinal stenosis (LSS), but their use is discussed highly controversial. Several level I studies suggest that IPD implantation is a viable alternative for both conservative treatment and decompression, but clear indications and contraindications are still missing. This study was designed to explore the perspectives and limitations of IPDs and to evaluate the role of these devices in general. MATERIAL AND METHODS The study is based on a questionnaire sent to all hospitals registered in the German Hospital Address Register 2010 with an orthopedic, neurosurgerical, or spine surgery department (n = 1,321). The questionnaire was reviewed by experienced spine surgeons and statisticians, and included both single-response, close-ended, and multiple-response open-ended questions. RESULTS We received 329 (24.9%) entirely analyzable questionnaires. A total of 164 respondents (49.8%) stated that IPDs are a treatment option for LSS, and 135 of the 164 respondents (82.3%) use them. Poor clinical experience (60%) and lack of evidence (53.9%) are the main reasons cited for not using IPDs. We detected a high negative correlation between the size of the hospital, the number of outpatients and inpatients treated for LSS and other spine pathologies, and the use of IPDs (p = 0.001). Most respondents prefer the combination of open decompression and IPD (64.4%; n = 87). A total of 9.6% (n = 13) of the users favor IPD implantation as a stand-alone procedure. Overall, 25.9%  n = 35  use both options. Most surgeons aim to relieve the facet joints (87.7%) and to stabilize a preexisting instability (75.4%). They recommend IPDs in the segments L2-L3 (77%), L3-L4 (98.5%), and L4-l5 (99.3%) and consider that IPD implanation also could be done at the L5-S1 segment (40.1%). Overall, 64.4% (n = 87) of the users recommend limiting IPD implantation to two segments. Infection (96.3%), fracture (94.8%), isthmic spondylolisthesis (77%), degenerative spondylolisthesis (higher than Meyerding I [57%]), lumbar spine scoliosis (48.1%), and osteoporosis (50.4%) are seen as contraindications for IPD. CONCLUSION No clear consensus exists among spine surgeons concerning the use of IPD for LSS treatment. The study showed that hospital-related parameters also influence decision making for or against the use of IPDs. However, despite the lack of evidence, the indications and contraindications which had been identified in the present study might contribute to improved outcomes after IPD implantation or at least prevent harm to patients.

In vivo application of an optical segment tracking approach for bone loading regimes recording in humans: A reliability study

This paper demonstrates an optical segment tracking (OST) approach for assessing the in vivo bone loading regimes in humans. The relative movement between retro-reflective marker clusters affixed to the tibia cortex by bone screws was tracked and expressed as tibia loading regimes in terms of segment deformation. Stable in vivo fixation of bone screws was tested by assessing the resonance frequency of the screw-marker structure and the relative marker position changes after hopping and jumping. Tibia deformation was recorded during squatting exercises to demonstrate the reliability of the OST approach. Results indicated that the resonance frequencies remain unchanged prior to and after all exercises. The changes of Cardan angle between marker clusters induced by the exercises were rather minor, maximally 0.06°. The reproducibility of the deformation angles during squatting remained small (0.04°/m-0.65°/m). Most importantly, all surgical and testing procedures were well tolerated. The OST method promises to bring more insights of the mechanical loading acting on bone than in the past.

Muscular forces affect the glycosaminoglycan content of joint cartilage: unloading in human volunteers with the HEPHAISTOS lower leg orthosis.

Background and purpose — Unloading alters the thickness of joint cartilage. It is unknown, however, to what extent unloading leads to a loss of glycosaminoglycans (GAGs) in the cartilage tissue. We hypothesized that muscle forces, in addition to axial loading, are necessary to maintain the joint cartilage GAG content of the knee and the upper and lower ankle. Patients and methods — The HEPHAISTOS orthosis was worn unilaterally by 11 men (mean age 31 (23–50) years old) for 56 days. The orthosis reduces activation and force production of the calf muscles while it permits full gravitational loading of the lower leg. MRI measurements of the knee and ankle were taken before the intervention, during the intervention (on day 49), and 14 days after the end of the intervention. Cartilage segmentation was conducted semiautomatically for the knee joint (4 segments) and for the upper (tibio-talar) and lower (subtalar) ankle joints (2 segments each). Linear mixed-effects (LME) models were used for statistical analysis. Results — 8 volunteers completed the MRI experiment. In the lower ankle joint, differences in ΔT1 were found between the end of the intervention and 14 days after (p = 0.004), indicating a decrease in GAG content after reloading. There were no statistically significant differences in ΔT1 values in the knee and upper ankle joints. Interpretation — Our findings suggest that in addition to gravitational load, muscular forces affect cartilage composition depending on the local distribution of forces in the joints affected by muscle contraction.

Assessment of Lumbar Intervertebral Disc Glycosaminoglycan Content by Gadolinium-Enhanced MRI before and after 21-Days of Head-Down-Tilt Bedrest

During spaceflight, it has been shown that intervertebral discs (IVDs) increase in height, causing elongation of the spine up to several centimeters. Astronauts frequently report dull lower back pain that is most likely of discogenic origin and may result from IVD expansion. It is unknown whether disc volume solely increases by water influx, or if the content of glycosaminoglycans also changes in microgravity. Aim of this pilot study was to investigate effects of the spaceflight analog of bedrest on the glycosaminoglycan content of human lumbar IVDs. Five healthy, non-smoking, male human subjects of European descent were immobilized in 6° head-down-tilt bedrest for 21 days. Subjects remained in bed 24 h a day with at least one shoulder on the mattress. Magnetic Resonance Imaging (MRI) scans were taken according to the delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC) protocol before and after bedrest. The outcome measures were T1 and ΔT1. Scans were performed before and after administration of the contrast agent Gd-DOTA, and differences between T1-values of both scans (ΔT1) were computed. ΔT1 is the longitudinal relaxation time in the tissue and inversely related to the glycosaminoglycan-content. For data analysis, IVDs L1/2 to L4/5 were semi-automatically segmented. Zones were defined and analyzed separately. Results show a highly significant decrease in ΔT1 (p<0.001) after bedrest in all IVDs, and in all areas of the IVDs. The ΔT1-decrease was most prominent in the nucleus pulposus and in L4/5, and was expressed slightly more in the posterior than anterior IVD. Unexpected negative ΔT1-values were found in Pfirrmann-grade 2-discs after bedrest. Significantly lower T1 before contrast agent application was found after bedrest compared to before bedrest. According to the dGEMRIC-literature, the decrease in ΔT1 may be interpreted as an increase in glycosaminoglycans in healthy IVDs during bedrest. This interpretation seems contradictory to previous findings in IVD unloading.

Complications after cryosurgery with new miniature cryoprobes in long hollow bones: An animal trial

BackgroundIn vitro studies show that new miniature cryoprobes are suitable for cryoablation of bone tissue. The aim of this animal trial on 24 sheep was to examine the perioperative complications, particularly the danger of embolism, of cryoablation when using miniature cryoprobes.MethodsCryoablations with 2 freeze-thaw cycles each were carried out in the epiphysis of the right tibia and the metaphysis of the left femur. Pulmonary artery pressure (PAP) and central venous pressure (CVP) were measured. Throughout the intra- and perioperative phase, heart rate and oxygen saturation by pulse oxymetry, blood gas and electrolytes were monitored regularly. Postoperative complications were examined up to 24 weeks postoperativ.ResultsAs result, no significant increase of PAP, CVP or heart rate were observed. Blood gases were unremarkable, with pO2 and pCO2 remaining constant throughout the operation. Regarding pH, standard bicarbonate and base excess, only a non-significant shift towards a slight acidosis was seen. There was a mean hemoglobin decrease of 0.5 g/dl. One animal showed postoperative wound infection and wound edge necrosis. No major peri- and postoperative complications associated with cryosurgery of bone were observed, especially regarding clinically relevant pulmonary embolism.ConclusionSurgery with new types of miniature cryoprobes appears to be a safe alternative to or a complement to conventional resection of abnormal bone tissue.