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Introduction: Direct skeletal attachment of prostheses has previously been shown to improve patient-reported outcome (PRO) measures of individuals with transfemoral amputation (TFA) at 2-year follow-up. This prospective study reports the outcomes at 5-year follow-up. Methods: A total of 51 patients (55 legs) with TFA were included in a prospective study. Complications, success rate, and PRO measures were followed for 5 years. Results: The cumulative fixture survival rate at 5 years was 92%, and the revision-free survival rate was 45%. Thirty-four patients had 70 superficial infections. Eleven patients had 14 deep infections. Fifteen patients had mechanical complications. Four fixtures were removed (ie, one deep infection and three loosening). PRO measures showed significant improvements including more use of the prosthesis, better mobility, fewer issues, and improved physical health-related quality of life (all P < 0.0001) compared with baseline. Conclusion: Individuals with TFA at 5-year follow-up had significant improvement in PRO measures, but increases in deep infections and mechanical complications are concerning.

Purpose:It has been assumed that nucleus pulposus-induced activation of the dorsal root ganglion (DRG) may be related to an activation of sodium channels in the DRG neurons. In this study we assessed the expression of Nav 1.8 and Nav 1.9 following disc puncture.Method:Thirty female Sprague-Dawley rats were used. The L4/L5 disc was punctured by a needle (n=12) and compared to a sham group without disc puncture (n=12) and a naive group (n=6). At day 1 and 7, sections of the left L4 DRG were immunostained with anti-Nav 1.8 and Nav 1.9 antibodies.Result:At day 1 after surgery, both Nav 1.8-IR neurons and Nav 1.9-IR neurons were significantly increased in the disc puncture group compared to the sham and naive groups (pConclusion:The findings in the present study demonstrate a neuronal mechanism that may be of importance in the pathophysiology of sciatic pain in disc herniation.

To investigate the effects on evoked thalamic neuronal activity of application of notochordal cells and chondrocyte-like cells derived from nucleus pulposus (NP) onto a dorsal root ganglion (DRG) and to compare these effects with a previously reported increased thalamic activity induced by NP.Nucleus pulposus was harvested from tail discs of adult rats and the disc cells were separated into two cell populations, notochordal cells and chondrocyte-like cells. The two cell populations were applied separately, or in combination, to the L4 DRG of anaesthetised female Sprague-Dawley rats during acute electrophysiological experiments. In control experiments, cell suspension medium was applied on the DRG. Recordings from the contralateral thalamus were sampled for 40 min while electrically stimulating the ipsilateral sciatic nerve at above Aδ-fibre thresholds.Application of notochordal cells resulted in a decrease in evoked thalamic activity within 10 min while chondrocyte-like cells did not induce any changes during the 40 min of recording. The difference in evoked thalamic activity 40 min after notochordal and chondrocyte-like cell application, respectively, was statistically significant. Neither an increased concentration of chondrocyte-like cells alone nor a combination of the two cell populations induced any changes in thalamic activity.Separate exposure of the DRG to the two NP-derived cell populations induced different effects on evoked thalamic activity, but none of the tested cell samples induced an increase in neuronal activity similar to that previously observed with NP. This indicates a high complexity of the interaction between NP and nervous tissue.

The P2X(3) receptor is a ligand-gated cation channel that is activated by extra cellular adenosine triphosphate (ATP) found in the dorsal root, trigeminal and nodose ganglia. It is one of the receptors transmitting nociceptive information of injuries and inflammation of the periphery by endogenous ATP released from damaged cells. The present study was performed in order to evaluate if there was an increased expression of P2X(3)-immunoreactivity in dorsal root ganglion (DRG) neurons after experimental disc herniation. There were four groups: exposure of the left L4 dorsal root ganglion and incision of the L4-L5 disc, exposure and slight displacement of the left L4 dorsal ganglion, sham exposure of the L4 dorsal root ganglion, and normal. Seven days after surgery, the DRG's were collected, sectioned and stained immunohistochemically for the P2X(3) receptor. The expression of P2X(3) increased significantly following incision of the L4-5 disc compared to the normal group. Sham surgery induced a minor, although statistically significant increase. Mechanical displacement did not induce any increased expression of the receptors. The study demonstrates that expression of the P2X(3)receptors in the DRG may be induced by local application of nucleus pulposus. This may increase our understanding of the pathophysiologic mechanisms related to disc herniation and sciatica.

In recognition of the value of research to the practice of spine care, Federico Balagué and Ferran Pellisé, at the time President and Secretary for EuroSpine, asked Margareta Nordin to set up a Task Force on Research (TFR) for EuroSpine during summer 2011. The concept was to stimulate and facilitate a research community within the society, through two main functions: (1) distribution of EuroSpine funds to researchers; (2) develop and deliver research training/education courses. What has the EuroSpine TFR accomplished since its inception?

We wished to establish a reproducible model for fracture fixation to be used in fracture healing research and therefore developed an external fixation construct and surgical procedure adapted to Sprague-Dawley rats. We evaluated the mechanical properties of the construct in brass rods and rat bone, in an Instron test machine with axial and transverse loading, and the in vivo performance. We found that the mechanical properties of the construct in brass rods were predictable and could be repeated in rat femora. In all tests, the axial load was about 10 times the transverse for the same degree of deformation. The stiffness among fixators was uniform. 1 mm pins caused about 50% less stiffness than 1.2 mm pins in axial loading of rat bone (p < 0.001) and brass rods (p < 0.001) as well as in transverse loading of brass rods (p < 0.001). Loosening of 1 or 2 screws that lock the pins to the fixator reduced stiffness by about 50% in axial loading of rat bone (p = 0.009) and brass rods (p = 0.05). A change in the distance between the bone surface and the fixator was linearly related to the stiffness in axial loading of rat bone (p < 0.001) and brass rods (p < 0.001) and in transverse loading of brass rods (p < 0.001). If the bone ends touched each other, the axial stiffness of the construct increased almost 10 times (265 N/mm), as compared to a fracture gap size of 2 mm (31 N/mm). In vivo experiments had a complication rate of less than 10% when we used 1.2 mm pins, 6 mm offset and rats weighing 350-450 g. Our method and device for experimental external fixation of rat femora are reliable and the findings are reproducible. These can be used in bone repair and fracture healing research.

It is known that 24 h or more after epidural application of autologous nucleus pulposus, functional and structural changes are established in adjacent nerve roots. It is, however, not known how soon after the application these changes appear. The aim of this study was to reduce the exposure duration to 3 h and to evaluate nerve function and histological changes in the nerve tissue during this time period. A total of 12 pigs was used. In ten pigs, autologous nucleus pulposus (NP) was applied epidurally on the cauda equina. Nerve function was then monitored for 3 h by measurements of muscle action potentials (MAP) in the tail muscles, following nerve root stimulation cranial to the exposed zone. In five of the ten pigs with NP application, nerve root compression to 50 mm Hg was added by means of an inflatable balloon. In two control animals, neither NP nor compression was applied. At the end point, nerve root specimens were harvested for histological assessment. No reduction of MAP amplitude was detected in any of the series. However, there was an epidural accumulation of leucocytes and mast cells, as well as minor axonal and Schwann cell changes in both the NP and NP+ compression series, as compared to the control series. Morphological changes in terms of an epidural inflammatory reaction and minor axonal and Schwann cell damage may thus be demonstrated within 3 h of NP application, with or without compression. However, there is no functional deterioration of the nerve roots detectable within this time period.

In an attempt to evaluate whether experimental disc herniation can result in changes in walking pattern, presumably indicating pain, four groups of rats – sham (n = 5), disc puncture (NP, n = 5), displacement of nerve root and ganglion (DIS, n = 5), and the combination of disc puncture and displacement (NP + DIS, n = 6) – were assessed when walking in a Plexiglas corridor at day 2–14 after surgery. All surgical procedures were performed at the L4–5 level on the left side. Step length analysis showed that rats in the NP and DIS series had no difference between the legs initially, but a tendency towards slightly shorter left steps at day 8–12, whereas the animals in the NP + DIS series had slightly shorter right steps day 2–10. However, no statistically significant differences compared with the sham series could be detected for any of the groups. Nerve dysfunction on the operated side was only observed on one occasion in two rats and on 2 days in one rat, all from the NP + DIS series. Apparent limping was seen in three of the animals in the NP + DIS series and in one in the DIS series. Limping and nerve dysfunction only co-incided on one occasion out of a total of 13 observations of limping, suggesting that the limping was induced by pain and not neurologic deficit. In conclusion, the combination of epidural nucleus pulposus and displacement induced a limping whereas nucleus pulposus or displacment alone did not. Assessment of limping thus seemed to provide adequate information of presence of pain, but step length measurement did not provide any useful data. Although walking analysis may be a valuable assessment of sciatic pain, better modalities must be developed to analyze experimentally induced nerve root pain.

This study investigated detection thresholds of vibrometric stimuli in patients with transfemoral amputation supplied with osseointegrated (OI) and socket-suspended prostheses. It included 17 patients tested preoperatively with socket-suspended prostheses and after 2 yr with OI prostheses and a control group (n = 17) using socket-suspended prostheses, evaluated once. Assessments on the prosthetic and intact feet were conducted at six frequencies (8, 16, 32, 64, 125, and 250 Hz). Furthermore, measurements were conducted to investigate how vibrometric signals are transmitted through a test prosthesis. The results showed that the OI group had improved ability to detect vibrations through the prosthesis at 125 Hz (p = 0.01) at follow-up compared with the preoperative measurement. Compared with the control group, the OI group at follow-up had better ability to detect high frequency vibrations through the prosthesis (125 Hz, p = 0.02; 250 Hz, p = 0.03). The vibrometric signal transmitted through the test prosthesis was reduced at 8, 125, and 250 Hz but was amplified at 16, 32, and 64 Hz. Differences between the OI and the control groups were found in the highest frequencies in which the test prosthesis showed reduction of the vibrometric signal. The study provides insight into the mechanisms of vibration transmission between the exterior and bone-anchored as well as socket-suspended amputation prostheses.

Low doses of methotrexate (MTX) are safe and effective for treating adult and juvenile rheumatoid arthritis. However, because this powerful anti-inflammatory drug might negatively influence the healing of wounds and fractures, MTX administration is often stopped during surgical procedures. The present study assesses the effects of low- and high-dose MTX on early inflammatory processes and bone healing in an experimental model of fracture. Thirty male Sprague-Dawley rats were assigned to low- and high-dose MTX and control groups. A femur was cut using a reciprocating saw and a 2-mm fracture gap was made using a fixator. One or four weeks thereafter, macrophages were immunostained and new bone formation was histomorphometrically measured. Significantly less new bone was formed in the high-dose MTX, than in the control group (p< 0.01), whereas bone formation did not significantly differ between the low-dose MTX and control groups. These results suggested that a low dose of MTX does not affect the early process of endochondral bone formation during fracture healing, whereas a high dose might delay the progress of new periosteal bone formation. Although more macrophages were found in the groups treated with MTX, their impact on surrounding inflammatory processes remains unclear.

Comparative epidemiological study of minor cervical spine trauma (frequently referred to as whiplash injury) based on data from the Comité Européen des Assurances (CEA) gathered in ten European countries. To determine the incidence and expenditure (e.g., for assessment, treatment or claims) for minor cervical spine injury in the participating countries. Controversy still surrounds the basis on which symptoms following minor cervical spine trauma may develop. In particular, there is considerable disagreement with regard to a possible contribution of psychosocial factors in determining outcome. The role of compensation is also a source of constant debate. The method followed here is the comparison of the data from different areas of interest (e.g., incidence of minor cervical spine trauma, percentage of minor cervical spine trauma in relationship to the incidence of bodily trauma, costs for assessment or claims) from ten European countries. Considerable differences exist regarding the incidence of minor cervical spine trauma and related costs in participating countries. France and Finland have the lowest and Great Britain the highest incidence of minor cervical spine trauma. The number of claims following minor cervical spine trauma in Switzerland is around the European average; however, Switzerland has the highest expenditure per claim at an average cost of 35,000.00 euros compared to the European average of 9,000.00 euros. Furthermore, the mandatory accident insurance statistics in Switzerland show very large differences between German-speaking and French- or Italian-speaking parts of the country. In the latter the costs for minor cervical spine trauma expanded more than doubled in the period from 1990 to 2002, whereas in the German-speaking part they rose by a factor of five. All the countries participating in the study have a high standard of medical care. The differences in claims frequency and costs must therefore reflect a social phenomenon based on the different cultural attitudes and medical approach to the problem including diagnosis. In Switzerland, therefore, new ways must be found to try to resolve the problem. The claims treatment model known as "Case Management" represents a new approach in which accelerated social and professional reintegration of the injured party is attempted. The CEA study emphasizes the fundamental role of medicine in that it postulates a clear division between the role of the attending physician and the medical expert. It also draws attention to the need to train medical professionals in the insurance business to the extent that they can interact adequately with insurance professionals. The results of this study indicate that the usefulness of the criterion of so-called typical clinical symptoms, which is at present applied by the courts to determine natural causality and has long been under debate, is inappropriate and should be replaced by objective assessment (e.g. accident and biomechanical analysis). In addition, the legal concept of adequate causality should be interpreted in the same way in both third party liability and social security law, which is currently not the case.

An autoimmune response to herniated nucleus pulposus has been proposed to constitute a pathophysiologic mechanism for inducing sciatica based on the fact that nucleus pulposus under normal conditions is excluded from the development of immunological tolerance. The manifestation of an autoimmune response comprises different steps starting with antigen capture, continuing with activation of T helper (T(H)) cells and ending with production of autoantibodies. Activated T(H) cells differentiate into either T(H)1 cells, predominately producing proinflammatory cytokines such as interferon gamma (IFNgamma) or a T(H)2 subset mainly producing anti-inflammatory cytokines such as interleukin-4 (IL-4). The aim of the present study was to examine if exposure of autologous nucleus pulposus (NP) to the immune system for 3 weeks is potent enough to prime T(H) cells to differentiate into T(H)2 cells. The study was performed in a pig model allowing the exposure of NP to the immune system. To assess the polarization of T(H) cells the intracellular production of IFNgamma and IL-4 was measured in T cells by using flow cytometry. The revealed predominant production of IL-4 together with low production of IFNgamma in T cells after NP exposure to the immune system indicates that nucleus pulposus may prime T(H) cells to develop into IL-4-producing T(H)2 cells after being exposed to the immune system, for example, in association with disc herniation.

This is the first report on prospective outcome for individuals treated with bone-anchored trans-femoral amputation prostheses (OI-prostheses) using the method of osseointegration. The aim was to analyze general and condition-specific health related quality of life (HRQL) at 2-year follow-up as compared to the preoperative situation. The study population consists of the first 18 consecutively treated patients (8 male/10 female, mean age 45 years) in a clinical investigation with amputations mainly caused by trauma and tumour. At inclusion the mean time since the amputation was 15 years (10 months - 33 years). Two self-report questionnaires were answered preoperatively and at follow-up: the SF-36 Health Survey (SF-36) and the Questionnaire for persons with a Transfemoral Amputation (Q-TFA). At follow-up 17/18 patients used the OI-prosthesis; one did not due to pain and loosening of the implant. Four of the scales of the SF-36 (Physical Functioning, Role Functioning Physical, Bodily Pain and Physical Component Score) and all four scores of Q-TFA (Prosthetic Use, Prosthetic Mobility, Problems and Global Health) were statistically significantly improved at follow-up showing superior general physical HRQL, increased prosthetic use, better prosthetic mobility, fewer problems and a better global amputation situation. Thus, osseointegrated prostheses represent a promising development in the rehabilitation of individuals with transfemoral amputation and increase their quality of life.

Reprinted with permission from Lippincott Williams & Wilkins, Rydevik B, Editorial Preface: The Bone and Joint Decade 2000–2010 Task Force on Neck Pain and Its Associated Disorders, SPINE, Volume 33, Number 4S, pp S3

Different fracture fixation techniques and fracture environment influence bone formation in healing fractures. However, the influence on the development of biomechanical properties has not been clear described. We evaluated the influence of fracture fixation stability and fracture environment on mechanical properties in healing femoral fractures in rats.Animals were treated surgically with external fixation: 1 group (27 rats) with 0-mm fracture gap size with bone ends touching, corresponding to an axial stiffness of 265 (SD 34) N/mm, and a second group (27 rats) with 2-mm fracture gap size corresponding to an axial stiffness of 30 (SD 2.1) N/mm. From each group, 6-7 animals were killed at 2, 4, 6 and 12 weeks. Torsional test revealed a delay in torsional stiffness in fractures in group 2 compared to group 1. In group 2, the torsional stiffness of the contralateral femora was found to be greater at 12 weeks than the torsional stiffness in group 1.We found that during fracture healing, the development of torsional stiffness corresponds to the magnitude of endochondral ossification and late response of bone formation. A significantly increased torsional stiffness in the non-fractured leg of rats with delayed fracture healing was also found, possibly indicating a response to loading conditions or a systemic stimulation of bone mass.

Main problem. Nucleus pulposus and/or chronic compression can induce spinal nerve root injury. Inflammation has been proposed as having major importance in the pathophysiologic mechanisms involved in the induction of such injuries. Corticosteroids, potent anti-inflammatory drugs, have been demonstrated to reduce nucleus pulposus-induced spinal nerve root injury. The aim of the present study was to assess the effects of two potent nonsteroidal anti-inflammatory drugs (NSAIDs), diclofenac and ketoprofen, in experimental nucleus pulposus-induced spinal nerve root injury in a pig model. Methods. Eighteen pigs were included in the study. Autologous nucleus pulposus was harvested from a lumbar disc and applied locally around the first sacral nerve root after a partial laminectomy of the first and second sacral vertebrae. Six pigs were treated with daily intramuscular injections of diclofenac, 3 mg/kg body weight, for 7 days. Six other pigs were treated with daily intramuscular injections of ketoprofen, 4 mg/kg body weight, for 7 days. As controls, six pigs received injections with physiologic saline. After 7 days, the pigs were reanesthetized and the nerve conduction velocity over the exposed nerve root area was determined. Results. The nerve conduction velocity was significantly higher in pigs treated with diclofenac than in the saline-treated controls, (57±6 m/s vs 38±18 m/s, P

Proinflammatory cytokines have been identified in herniated intervertebral discs in humans, and such cytokines have experimentally been demonstrated to be important in the pathophysiological mechanisms of disc herniation. Cerebrospinal fluid (CSF) and serum concentrations of interleukin (IL)-1beta IL-6, IL-8, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha were investigated using the enzyme-linked immunosorbent assay (ELISA) technique in 39 patients with lumbar disc herniation and sciatica. Pain duration and pain intensity (visual analogue scale, VAS) were recorded at inclusion, and a clinical examination was performed evaluating neurological findings. The extent of disc herniation (protrusion or extrusion/sequestration) was evaluated perioperatively. Normal concentrations of IL-1beta, IL-6, IFN-gamma and TNF-alpha were present in CSF and serum in almost all patients with lumbar disc herniation. The concentrations of IL-8 in CSF were increased in 12 out of 39 patients, and these increased levels of IL-8 correlated to a short duration of pain and to more pronounced herniation (extrusion or sequestration). No relationship between IL-8 concentrations in CSF and pain intensity, positive neurological findings or a positive straight leg-raising (SLR) test was found. The observation of increased concentrations of IL-8 in CSF in patients with a short duration of symptoms supports the concept of the initial involvement of inflammatory mechanisms after a disc herniation. The finding that most of the patients with increased concentrations of IL-8 in CSF had an extrusion or a sequestration may suggest that the increase in IL-8 is related to mechanical nerve root compression, but may also indicate a biochemical effect exerted by the herniated disc on the surrounding tissue. Further studies on the potential role of IL-8 as a biomarker for disc herniation are warranted.

Limited data are available about the long-term outcome of surgical treatment for lumbar spinal stenosis, and there is a wide variation in reported success rates. There is also a controversy regarding differences in long-term outcome between patients undergoing decompressive surgery alone and those undergoing both decompression and fusion. The aim of this study was to evaluate the long-term clinical outcome and possible complications of decompressive surgery, with special reference to possible differences between patients undergoing fusion, with or without instrumentation, and those undergoing decompression alone. All 124 patients undergoing first-time surgery for lumbar spinal stenosis between 1982 and 1991 at our department were included, and their medical records were reviewed retrospectively. Ninety-six of the patients were available for follow-up and were re-examined by an independent investigator and assessed with a questionnaire after a mean follow-up period of 7.1 (range 4.0–12.2) years. Sixty-five percent of all the patients at the follow-up were subjectively satisfied. Eighty-eight percent of the patients reported constant or daily leg pain preoperatively compared to 43% at follow-up. Constant or daily low back pain was reported by 83% of the patients preoperatively compared to 45% at follow-up. Improvement in walking capacity was found in most patients, and only 4% of the patients who had a preoperatively documented maximum walking distance reported a decreased walking capacity. Twenty-four (25%) of all patients used analgesics daily at the time of follow-up, 34 patients (35%) occasionally and 38 patients (40%) never. The patients with fusions, instrumented or non-instrumented, did not differ significantly from the unfused patients regarding any of the above-mentioned parameters. The results of the study showed that most patients demonstrated a considerable improvement in walking capacity at follow-up. This improvement was significant (P < 0.001) and of clinical importance. A significant improvement regarding both low back pain and leg pain was found postoperatively compared to preoperatively (P < 0.001). There were no statistical differences, judged by all the evaluated parameters, regarding the clinical outcome between patients who were fused and those who were not. Neither were any significant differences found between instrumented fusions compared to uninstrumented fusions. In accordance with most other long-term follow-up studies, about two-thirds (65%) of the patients claimed a satisfactory result at follow-up.

In the present study the psychophysical detection threshold levels for mechanical stimulation of 32 prosthetic limbs were determined. Prosthetic limbs were anchored to the bone by means of an implant (n=17) or supported by a socket enclosing the amputation stump (n=15). Detection threshold levels were assessed for pressure and vibratory stimulation of the prosthesis and the limb at the contralateral side (control). Following vibratory stimulation, thresholds were increased on an avarage 20% for socket prostheses, but approached those of the control for bone-anchored prostheses. For pressure stimulation, thresholds were increased up to 60% for socket prostheses and 40% for bone-anchored prostheses compared to the control. While bone-anchored prostheses yielded significantly lower threshold levels than socket prostheses, there was no significant difference between both treatments regarding pressure stimulation. Results were applicable to both upper and lower limb amputees. It could be concluded that detection thresholds for pressure and especially vibratory stimulation of prosthetic limbs were generally higher than for control limbs. The outcome was related to the prosthetic limb design with bone-anchored prostheses yielding better perception than socket prostheses. All correspondence to be addressed to R. Branemark

Although it is well established that nucleus pulposus cells may induce structural and functional changes in adjacent nerve roots when placed epidurally, it is not known whether this is due to direct neurotoxic effects or whether the nerve roots are affected indirectly by reduction of nutrition and inflammatory/immunologic mechanisms. In the present study we assessed the effects of various tissues on cultured dorsal root ganglions from newborn rats. Nucleus pulposus was found to have a toxic effect on the axons by blocking axonal outgrowth, but no similar effects on the nerve cell bodies (extra-ganglionic nerve cell density, nerve cell arborisation) were found as compared to the series with only culture medium. Sterile water for 1 or 24 h (positive controls) induced significant effects by all four criteria, whereas medium without nerve growth factor, fat and frozen nucleus pulposus had no statistically significant effects. The study thus showed that there are direct axonotoxic effects induced by the nucleus pulposus, and since frozen nucleus pulposus did not have any effects, it may be assumed that the mechanisms are related to substances produced by the nucleus pulposus cells. The presented model allows for future studies on the neurotoxic properties of nucleus pulposus cell-derived candidate substances.

Intradiscal injection of chymopapain for the treatment of sciatica due to disc herniation has been used for more than 25 years, but is still under debate. We review the indications, complications, and clinical results, and discuss the tissue effects of chymopapain. The results following surgical disc removal versus chymopapain injection indicate that surgery with removal of the disc hernia through a small laminotomy remains the documented treatment of choice for patients with proven disc herniation and sciatica in whom conservative treatment has failed.

Longitudinal and radial tissue-fluid pressure distributions were determined beneath and adjacent to wide (12 and 18 cm) pneumatic tourniquet cuffs placed on intact human cadaveric arms and legs, respectively. Tissue fluid pressures exhibited relatively broad maxima at midcuff, and in most cases showed no differences at the various depths studied. Limb circumference was not a determining factor in the transmission of pressure to deeper tissue. We also investigated the effect of four cuff sizes (4.5, 8, 12, and 18 cm) on eliminating blood flow to the lower legs of normal subjects. The cuff pressure required to eliminate blood flow decreased as cuff width increased; thigh circumference was a determining factor in the pressure required to eliminate blood flow while using the smaller cuffs, but not while using the 18-cm cuff. Thus, wide cuffs transmit a greater percentage of the applied tourniquet pressure to deeper tissues than conventional cuffs; accordingly, lower cuff pressures are required, which may minimize soft-tissue damage during extremity surgery.