Increase In Intramedullary Pressure Research Articles

Cemented stems in healthy elderly patients result in higher hypoxia despite a paradoxical lower femoral increase of intramedullary pressure.

Hypoxia is a well-known complication in cemented arthroplasty; however, it is not known whether the level of hypoxia is related to the intramedullary pressure or to the age of the patient; therefore, we studied the intramedullary pressure and level of hypoxia in patients undergoing cemented arthroplasty. A prospective study was performed during cemented arthroplasties in 25 patients with an average age of 66.2 ± 12.1 years old. The intramedullary pressure (IMP) was measured by placing a pressure transducer within the bone while simultaneously measuring the pulse oximetry arterial oxygen saturation (SpO2), pulse, and blood pressure. These variables were obtained immediately after spinal anaesthesia, five minutes after cementation, and 15 minutes after prosthesis insertion. One hundred percent of patients had hypoxia at some level, but 83% of elderly patients (older than 66.5 years) had hypoxia (SpO2 <94%) as compared to only 23% of younger patients (p = 0.006). In the group of young patients, IMP was roughly increased 32 times as compared with baseline level, with as consequences a decrease of 4% of SpO2 (from 98.3 to 94.15%); in the elderly group, the IMP was only increased 20 times, but a decrease of 6% of SpO2 (from 97.25 to 91%) was observed. This series demonstrated higher hypoxia in elderly healthy patients despite a paradoxical lower femoral increase of intramedullary pressure as compared with younger patients. This hypoxia is probably not only related to the cement but also to the patient's age with decline of maximum oxygen uptake capacity and increase bone porosity. ClinicalTrials.gov Identifier: NCT03930537 https://clinicaltrials.gov/ct2/show/NCT03930537.

Dynamic changes in intramedullary pressure 72 hours after spinal cord injury.

Intramedullary pressure increases after spinal cord injury, and this can be an important factor for secondary spinal cord injury. Until now there have been no studies of the dynamic changes of intramedullary pressure after spinal cord injury. In this study, telemetry systems were used to observe changes in intramedullary pressure in the 72 hours following spinal cord injury to explore its pathological mechanisms. Spinal cord injury was induced using an aneurysm clip at T10 of the spinal cord of 30 Japanese white rabbits, while another 32 animals were only subjected to laminectomy. The feasibility of this measurement was assessed. Intramedullary pressure was monitored in anesthetized and conscious animals. The dynamic changes of intramedullary pressure after spinal cord injury were divided into three stages: stage I (steep rise) 1-7 hours, stage II (steady rise) 8-38 hours, and stage III (descending) 39-72 hours. Blood-spinal barrier permeability, edema, hemorrhage, and histological results in the 72 hours following spinal cord injury were evaluated according to intramedullary pressure changes. We found that spinal cord hemorrhage was most severe at 1 hour post-spinal cord injury and then gradually decreased; albumin and aquaporin 4 immunoreactivities first increased and then decreased, peaking at 38 hours. These results confirm that severe bleeding in spinal cord tissue is the main cause of the sharp increase in intramedullary pressure in early spinal cord injury. Spinal cord edema and blood-spinal barrier destruction are important factors influencing intramedullary pressure in stages II and III of spinal cord injury.

Spinal nociceptive transmission by mechanical stimulation of bone marrow.

BackgroundSince bone marrow receives innervation from A-delta and C-fibers and since an increase in intramedullary pressure in bone marrow may induce acute pain in orthopedic patients during surgery and chronic pain in patients with bone marrow edema, skeletal pain may partly originate from bone marrow. Intraosseous lesions, such as osteomyelitis and bone cancer, are also known to produce cutaneous hypersensitivity, which might be referred pain from bone. However, little is known about pain perception in bone marrow and referred pain induced by bone disease. Thus, we carried out an in vivo electrophysiological study and behavioral study to determine whether increased intraosseous pressure of the femur induces acute pain and whether increased intraosseous pressure induces referred pain in the corresponding receptive fields of the skin.ResultsIntraosseous balloon inflation caused spontaneous pain-related behavior and mechanical hyperalgesia and allodynia in the lumbosacral region. Single neuronal activities of spinal dorsal horn neurons were extracellularly isolated, and then evoked responses to non-noxious and noxious cutaneous stimuli and intraosseous balloon inflation were recorded. Ninety-four spinal dorsal horn neurons, which had somatic receptive fields at the lower back and thigh, were obtained. Sixty-two percent of the wide-dynamic-range neurons (24/39) and 86% of the high-threshold neurons (12/14) responded to intraosseous balloon inflation, while none of the low-threshold neurons (0/41) responded to intraosseous balloon inflation. Spinally administered morphine (1 µg) abolished balloon inflation-induced spontaneous pain-related behavior and mechanical hyperalgesia in awake rats and also suppressed evoked activities of wide-dynamic-range neurons to noxious cutaneous stimulation and intraosseous balloon inflation.ConclusionsThe results suggest that mechanical stimulation to bone marrow produces nociception, concomitantly producing its referred pain in the corresponding skin fields. These mechanisms might contribute to pain caused by skeletal diseases.

Animal models to assess the local and systemic effects of nailing: review of the literature and considerations for future studies.

Numerous experimental studies have been performed to investigate the adverse effects of reamed versus unreamed nailing in isolated or combined trauma models. However, the translational relevance is still discussed controversially. A systemic review of the literature was performed. An increase of intramedullary pressure with liberation of emboli to the venous and systemic circulation associated with reamed and unreamed nailing has been well described. Reamed nailing, however, seems to have superior clinical results in terms of fracture healing. The pathophysiologic effects, optimal timing, and technique of reamed nailing particularly in patients with multiple injuries continue to be controversial topics. Therefore, further experimental studies should focus on these topics as well as on the interaction of local and systemic processes particularly in the context of different surgical treatment strategies (Early Total Care vs. Damage Control Orthopaedics) to improve our understanding and approach to intramedullary nailing.

Cardiopulmonary Response to Reamed Intramedullary Nailing of the Femur Comparing Traditional Reaming With a One-Step Reamer-Irrigator-Aspirator Reaming System: An Experimental Study in Pigs

Intramedullary reaming and nailing increases intramedullary pressure. This may cause intravasation of bone marrow contents, leading to bone marrow embolization and altered cardiopulmonary function. Possible beneficial effects of attenuation of the intramedullary pressure increase by the use of a reamer-irrigator-aspirator (RIA) system were studied with the hypothesis that the RIA technique would cause lower numbers of pulmonary embolisms (PEs) and lesser cardiopulmonary affection than traditional reaming (TR). Intramedullary reaming and nailing was performed in intact femora of young Norwegian landrace pigs using either a standard intramedullary nailing technique (n = 8) or a RIA technique (n = 7). The hemodynamic and pulmonary effects were investigated during the reaming and nailing procedure and for 2 hours postoperatively. The animals were killed after 72 hours, and the lung/carcass weight ratio and the numbers of PEs were investigated. The pattern of the procedure-related hemodynamic and pulmonary effects did not differ significantly between the RIA and the TR groups. The RIA group had lower numbers (ns) of embolisms per square centimeter lung area than the TR group. After reaming with the TR device, two animals died of PEs, the first postoperative day. The patients with femoral shaft fracture and additional cardiopulmonary injury or preexisting reduced cardiopulmonary function, however, need special attention, and the use of RIA may, in these cases, represent a better operative alternative with a lesser operative burden.

Fat extravasation due to unreamed and experimentally reamed intramedullary nailing of the sheep femur

Aim To compare systemic fat extravasation in unreamed and experimentally reamed nailing. Methods An osteotomy was created in the proximal third of the femoral shaft in 16 sheep, and intramedullary pressure increase and fat extravasation were monitored for the two nailing techniques. Results The highest intramedullary pressures, median 2700 mmHg, and highest percentages of fat extravasation, peaking at almost 90% of fat, were found for the unreamed nailing technique. The values for the reamed group were significantly lower. Conclusions The extravasation of intramedullary fat can be attributed to the great increase in intramedullary pressure that occurs during unreamed nailing. Correctly performed intramedullary reaming with the new reaming system produces lower pressures and much less systemic fat extravasation, reducing the risk for fat embolism.

Cardiopulmonary response to reamed intramedullary nailing of the femur with a traditional reaming system and a one-step reamer-irrigator-aspirator reaming system; an experimental study in pigs

There is general agreement that early internal stabilization in long bone fractures in severely injured patients is advantageous. Intramedullary reaming and nailing, however, include increased intramedullary pressure. This may cause intravasation of bone marrow contents, leading to bone marrow embolisation and altered cardiopulmonary function. Possible beneficial effects of attenuation of the intramedullary pressure increase by the use of a reamer-irrigator-aspirator (RIA) system were studied with the hypothesis that the RIA technique would cause lower numbers of pulmonary embolisms and lesser cardiopulmonary affection than after traditional reaming (TR).

Monitoring and controlling intramedullary pressure increase in long bone instrumentation: A study on sheep

Intramedullary reamed nailing causes elevation in intramedullary pressure and extravazation of intramedullary contents into the venous blood system. This study investigated the effect of an intramedullary suction system, recently developed in our laboratory, on the pressure and fat extravazation in isolated bovine bone and a sheep model. During reaming, the pressure with and without suction was recorded at each step of the procedure. Hemodynamic parameters of mean arterial blood pressure, pulmonary artery pressure, pulmonary arterial CO(2) (PaCO(2)), heart rate, and oxygen saturation were monitored. Blood and lung tissue samples were collected for the examination of medullary fat intravazation. The increases of intramedullary pressure were dramatically reduced in the suction group (p < 0.05) in both in vitro and in vivo experiments. PaCO(2) was significantly lower in the suction group than nonsuction group (32 vs. 40 mmHg, respectively, p = 0.02), while oxygen saturation was higher in the suction group (99 vs. 91 mmHg, respectively, p = 0.009). Histological data revealed a significant higher count of fat emboli in sheep lung tissue in the nonsuction group. Total lipids in lung specimens was lower in the suction group (7.6 mg/g tissue) than in the nonsuction group (13.6 mg/g, p = 0.04). The suction system appears to control the surge in intramedullary pressure and therefore prevent fat embolism.

Die intraspongiöse Patelladruckmessung in Abhängigkeit von der Funktionsstellung des Kniegelenkes

Degenerative alterations of the patello-femoral joint are often painful and cause an increase of intramedullary pressure. The intraspongious pressure of the patella is measured with a cannula after lateral drilling. Patients with chondromalacia or osteoarthrosis have an increased intramedullary pressure compared with normal patients. The degree of flexion of the knee-joint correlates with the intramedullary pressure. More flexion causes an increase of pressure as well in normal patella as in chondromalacia or in osteoarthrosis.

Chondromalacia of the patella and intraosseous pressure. A study of 43 patients

There are some hints concerning a relationship between the intraosseous pressure and degenerative changes in hyaline cartilage. With a specially constructed cannula we evaluated the intraosseous pressure in 43 patients in relation to the joint position (Extension/Flexion). In two groups we compared patients with and without degenerative changes in the hyaline cartilage, diagnosed by arthroscopy. Our results show, that patients with a chondromalacia have an increase of intramedullary pressure. These changes were discussed in the possible role of the pathology of chondromalacia patellae and retropatellar arthrosis.

A method of monitoring and controlling intramedullary pressure increase during long bone instrumentation

In amulticentre study coordinated by the Associationfor the Study of Internal Fixation, Ecke analysedthedataof1127patientswithfemoralshaftfracturesand reported an unexplained high incidence of pul-monary complications in patients younger than 30years if primary reamed nailing was done. Fat intra-vasation from the medullary canal was consideredthe main cause for the unexpected pulmonary insuf-ficiency.

Fat embolism: the reaming controversy

Intramedullary nailing is the preferred treatment method for stabilizing femoral diaphyseal fractures. Despite its superior biomechanical advantages over other implants, its use, particularly in selected groups of patients, has been questioned because of the possible harmful systemic effects of intramedullary reaming. The increase in intramedullary canal pressure during intramedullary nailing can result in intravasation of bone marrow and fat into the venous blood system. The subsequent consequences can be fat embolism syndrome (FES), adult respiratory distress syndrome (ARDS), and multiple organ failure. The lung seems to be the primary target for fat embolization and for the mediated effects primed by inflammatory reactions. In laboratory studies, both reamed and unreamed intramedullary nailing has been shown to alter selected pulmonary variables. Although transient, this effect appears to be more prominent with reamed than unreamed techniques. Additional studies are required to determine whether a subgroup of trauma patients is adversely affected by intramedullary reaming, thus necessitating other fixation techniques.

The influence of a one-step reamer-irrigator-aspirator technique on the intramedullary pressure in the pig femur

Increased intramedullary pressure in the femoral cavity causes intravasation of bone marrow content to the circulation which may lead to occlusion of pulmonary vessels and cardiorespiratory dysfunction. A one-step reamer-irrigator-aspirator (RIA) technique has been developed to reduce the intramedullary pressure (IMP) during the reaming procedure. This study was design to compare IMP with a standard reaming technique with IMP during reaming with the RIA system with a hypothesis that the RIA system would involve lower pressures. In a randomised study in 19 Norwegian landrace pigs reamed intramedullary nailing was performed with two different reamer devices. Nine animals were operated with a traditional reamer and 10 animals with RIA. One animal in the RIA group was excluded due to a perioperative femoral fracture, and three animals in the traditional group were excluded due to a perforation of the distal medial femoral cortex. The intramedullary pressure was registrated with a transducer-tipped pressure monitoring catheter during reaming. There was a significantly higher intramedullary pressure (P<0.05) during reaming in the traditional reamer group (mean 188+/-38 mmHg) than in the RIA group (mean 33+/-8 mmHg). Intramedullary pressures recorded before surgery, at the opening of the femoral cavity with an awl, by insertion of a guide wire, at insertion of the intramedullary nail, and 10 min after nail insertion showed no significant differences between the groups. The use of a one-step reamer-irrigator-aspirator technique in the pig femur induced less intramedullary pressure increase than the use of a traditional reamer.

Unraveling the riddle of syringomyelia

The pathophysiology of syringomyelia development is not fully understood. Current prevailing theories suggest that increased pulse pressure in the subarachnoid space forces cerebrospinal fluid (CSF) through the spinal cord into the syrinx. It is generally accepted that the syrinx consists of CSF. The here-proposed intramedullary pulse pressure theory instead suggests that syringomyelia is caused by increased pulse pressure in the spinal cord and that the syrinx consists of extracellular fluid. A new principle is introduced implying that the distending force in the production of syringomyelia is a relative increase in pulse pressure in the spinal cord compared to that in the nearby subarachnoid space. The formation of a syrinx then occurs by the accumulation of extracellular fluid in the distended cord. A previously unrecognized mechanism for syrinx formation, the Bernoulli theorem, is also described. The Bernoulli theorem or the Venturi effect states that the regional increase in fluid velocity in a narrowed flow channel decreases fluid pressure. In Chiari I malformations, the systolic CSF pulse pressure and downward motion of the cerebellar tonsils are significantly increased. This leads to increased spinal CSF velocities and, as a consequence of the Bernoulli theorem, decreased fluid pressure in narrow regions of the spinal CSF pathways. The resulting relatively low CSF pressure in the narrowed CSF pathway causes a suction effect on the spinal cord that distends the cord during each systole. Syringomyelia develops by the accumulation of extracellular fluid in the distended cord. In posttraumatic syringomyelia, the downwards directed systolic CSF pulse pressure is transmitted and reflected into the spinal cord below and above the traumatic subarachnoid blockage, respectively. The ensuing increase in intramedullary pulse pressure distends the spinal cord and causes syringomyelia on both sides of the blockage. The here-proposed concept has the potential to unravel the riddle of syringomyelia and affords explanations to previously unanswered clinical and theoretical problems with syringomyelia. It also explains why syringomyelia associated with Chiari I malformations may develop in any part of the spinal cord including the medullary conus. Syringomyelia thus preferentially develops where the systolic CSF flow causes a suction effect on the spinal cord, i.e., at or immediately caudal to physiological or pathological encroachments of the spinal subarachnoid space.

Einfache Lagerungshilfe zur Unterschenkelmarknagelung

Unterschenkelfrakturen in den mittleren drei Fünfteln werden in der Regel durch Marknagelung behandelt. Die Lagerung des Patienten auf einem Extensionstisch erfordert einen erheblichen zeitlichen Mehraufwand bei erhöhten intramedullären Drucken. Eine alternative Lagerung auf einem Normaltisch erfordert einen zusätzlichen Assistenten zur Fixierung des Beines und führt unwillkürlich zu ungewollten Bewegungen im Bein. Dadurch werden unnötig Ressourcen im OP gebunden. Eine einfache variable Lagerung des Beines auf einem Rahmen aus 4 Fixateur-Karbonstangen ermöglicht hingegen eine einfache Reposition und Nagelung mit einem Operateur und bei Bedarf einen zusätzlichen Assistenten. 50 Unterschenkelfrakturen wurden seit 1996 mit dieser Lagerungshilfe genagelt. Die durchschnittliche Operationszeit betrug bei gebohrten Nägeln 63 min und bei ungebohrten Nägeln 55 min. Zusätzliche Lagerungszeiten wurden vermieden.

Rinsing-suction reamer attenuates intramedullary pressure increase and fat intravasation in a sheep model.

Reamed intramedullary nailing causes an increase of intramedullary pressure. A new rinsing-suction reamer (RSR) can reduce this problem, and it was evaluated in animal experiments in comparison with the AO reamer (AOR) to see its effects on intramedullary pressure and fat intravasation. Reamed intramedullary nailing was performed in 14 sheep using the RSR or AOR. The following parameters were evaluated: intramedullary pressure, hemodynamics, blood tests, lung histology, and radiographs of the femur that was operated on. Intramedullary pressure during reaming was significantly (p < 0.001) lower with RSR (9 mm, 34 mm Hg; 9.5 mm, 4 mm Hg; 10 mm, 1 mm Hg) than AOR (9 mm, 750 mm Hg; 9.5 mm, 292 mm Hg; 10 mm, 138 mm Hg). There was a significantly (p < 0.05) higher increase of pulmonary resistance in AOR (from 144 +/- 84 dyne x s x cm to 391 +/- 169 dyne x s x cm) than in RSR (from 137 +/- 51 dyne x s x cm to 258 +/- 105 dyne x s x cm) after nailing and less intravenous fat measured in RSR (0.9; AOR, 2.9; p < 0.05) at all stages of reaming, at nail insertion (RSR, 0.3; AOR, 2.7; p < 0.05), and 30 seconds after nail insertion (RSR, 0.2; AOR, 1.1; p < 0.05) proved by the Gurd test. Pco2 increased (p < 0.05) in AOR (AOR, 36 +/- 5 vs. 40 +/- 7 mm Hg; RSR, 33 +/- 4 vs. 32 +/- 3 mm Hg) and pH dropped significantly (AOR, 7.49 +/- 0.06 vs. 7.45 +/- 0.05; RSR, 7.53 +/- 0.04 vs. 7.54 +/- 0.04; p < 0.05). Semiquantitative histologic analysis proved a significant higher pulmonary fat load in AOR (13.1 +/- 13.4) versus RSR (3.9 +/- 1.5, p = 0.00002). Because we found only a minimal increase of the pulmonary arterial pressure as a sign of pulmonary embolism, we conclude that by using the RSR, the systemic side effects caused by intravasation of medullary content during reaming could be reduced as far as possible.

A new irrigation-suction boring system facilities low-pressure intramedullary boring of isolated swine femurs

Intramedullary nailing is the treatment of choice for the stabilization of fractures of long tubular bones. An important disadvantage of this method is the increase in intramedullary pressure and the resulting release of fat into the venous blood system during reaming of the medullary canal. We have developed a new type of rinsing-suction-reamer (SSB) in order to minimize these disadvantages. Trials were initiated to investigate whether it is possible to ream the medullary canal with the SSB without pressure increase in comparison with the standard AO-reamer (AOB). Reamed intramedullary nailing was performed in 20 isolated pig femora. The intramedullary pressure was recorded continuously. While stepwise reaming was performed, the pressure only rose above the physiological level in AOB. During insertion of the guide wire and the nail, comparable values were measured for AOB and SSB. Our experiments show that reaming of the medullary canal is possible without a pressure increase using the SSB in comparison with AOB.

Intramedullary pressure increase and increase in cortical temperature during reaming of the femoral medullary cavity: the effect of draining the medullary contents before reaming.

Reaming is regarded as the most adverse aspect of the intramedullary nailing procedure since it leads not only to impairment of the vessels but also to an increase in intramedullary pressure and cortical temperatures which may in turn lead to aseptic cortical necroses and pulmonary dysfunction. Intramedullary pressure increase is considered to be the most detrimental of these factors. The aim of this study was to investigate the effect on intramedullary pressure and cortical temperature of removing the medullary fat before reaming. The fat was removed through a suction tube inserted proximally. The measurements were made on pairs of human femora whereby in one group the contents of the medulla were drained by suction before reaming. The pressure was measured in the mid diaphysis and in the metaphysis. The temperature was measured in the mid diaphysis. The femora were reamed in a water bath at 37 degrees C and at a constant insertion force. In comparison to the group which was not drained, the pressure for the 9.0 mm reamer in previously drained femora was reduced as follows: positive diaphyseal pressure by 88% (reamer insertion); positive metaphyseal pressure by 78% (reamer insertion); negative diaphyseal pressure by 84% (reamer withdrawal); negative metaphyseal pressure by 65% (reamer withdrawal). No significant difference was determined for temperature increase (median suction, 39.7 degrees C; median without suction, 39.4 degrees C). The removal of the medullary contents by suction before inserting reaming instruments leads to a considerable and statistically significant pressure reduction. If the medullary contents are not sucked out before reaming or insertion of unreamed nails, high intramedullary pressure and the risk of embolization is unaltered. Consequently new instruments should be developed to facilitate the removal of the medullary contents before commencing the reaming procedure or insertion of unreamed nails.

Pathophysiology of Fat Embolism after Intramedullary Reaming

Primary operative stabilization by an intramedullary procedure is the treatment of first choice for fractures of long tubular bones for reasons of biomechanics, the minimally invasive approach, and the early loadability of the injured limb. Additionally, in the case of multiple injuries, the pulmonary situation can be improved so that both the duration of ventilation and the period spent in intensive care are reduced. However, a postoperative increase in the incidence of posttraumatic lung failure has been found following early intramedullary nailing and seen as being linked to the procedure. The increase in intramedullary pressure occurring on intramedullary nailing or reaming can result in release of bone marrow and fat into the venous blood system. The potentially lethal consequences may be adult respiratory distress syndrome (ARDS) and multiple organ failure. For these reasons, a method was sought to bring about a reduction in intramedullary pressure at primary nailing. These efforts led to further developments in implant and reamer design as well as in nailing techniques. However, a clear release of fat was still apparent under these conditions. This review gives an overview of pathophysiologic aspects of reamed intramedullary nailing and suggestions for the optimal reaming system. A new-designed rinsing-suction reamer is briefly presented.

Canine panosteitis: an idiopathic bone disease investigated in the light of a new hypothesis concerning pathogenesis. Part 1: Clinical and diagnostic aspects

Panosteitis, an idiopathic bone disease of young dogs, was investigated in the light of a new, empirically based hypothesis governing its pathogenesis. Extensive clinical observations suggest a close relationship between the incidence of this disease and the commercialization of various protein-rich, high-calorie dog foods. The theory of an "osseous compartment syndrome" provides a hypothetical pathogenesis, which corroborates this findings. An excessive accumulation of protein causes intraosseous edema due to its osmotic effects. Because bone is a rigid compartment, this leads to an increase in intramedullary pressure and compression of blood vessels. Subsequent osseous ischemia leads to a deficient metabolic state (decreased oxygenation, inadequate influx of nutritive substances, local acidosis, decreased removal of metabolites, disruption of local biochemical processes, etc.), and a vicious circle is created due to the resulting local inflammation. The disease is aggravated by increased metabolism due to excessive physical activity. Within the context of a pilot study, clinical, radiographic, scintigraphic and thermographic examinations and a therapeutic trial with benzopyron were carried out. In addition, more modern investigative tools, including osteomyelography, magnetic resonance tomography and intraosseous pressure measurements were used to provide objective data concerning the pathogenesis of panosteitis. In most cases, clinical remission was seen within days of monotherapy with the proteolytic substance, benzopyron (Cumartrin). This finding appears to corroborate our hypothesis.