Dakhil-Jerew F, Jadeja H, Cohen A, Shepperd JA. In the fractured vertebrae, the continuity of cortical and structure of trabecula were damaged, which might affect the stability of screw placed in it. Lee et al. A non-union occurs when a spinal fusion procedure fails and the vertebral bones do not fuse together successfully. Wu ZX, Gong FT, Liu L, Ma ZS, Zhang Y, Zhao X, Yang M, Lei W, Sang HX. J Orthop Sci. The loosening rate was expected to be even higher in osteoporotic patients [17, 18]. The popping may just be the soft tissue becoming accustomed to its new position post surgery. Your doctor may also use screws, rods or plates to hold your vertebrae in . To the best of our knowledge, no study has evaluated such risk factors according to the extraction torque in vivo. Since 1.02Nm was significantly less than the 95% confidence interval of newly implanted screws, the pedicle screw loosening based on torque was defined as screws with an extraction torque less than or equal to 1.02Nm. Pihlajamaki H, Myllynen P, Bostman O. There is various hardware involved in the surgery that must be acknowledged to understand the benefits the procedure provides. Terms and Conditions, How Much Better Will I Be After Lumbar Fusion? I am having the same problem with the screws coming loose. The screws remained loose and the left S-1 screw was found to be broken (C, arrow) 28 . Low back pain may persist even though patients experience significant relief from the radiating pain in their legs. The thing about surgery is there is 'inherent risks'. There are several limitations in our study. Inclusion criteria were persisting midline . Feel free to write and keep me posted. It can occur without symptoms so the patient doesn't even know he or she has it. These slides can be re Chronic implant infection seems to play a role in PS loosening and ongoing pain, causing revision surgery after spinal fusion. The process of spinal fusion is costly . Glaser J, Stanley M, Sayre H, Woody J, Found E, Spratt K. A 10-year follow-up evaluation of lumbar spine fusion with pedicle screw fixation. Spinal muscle injury. Ensure stabilization at the surgical site. 3a. Before getting a spinal fusion, it is always a good idea to be aware of the risks and aftermaths associated with it. What Happens If My New Spinal Hardware Breaks Or Shifts? How do I know if my spinal fusion has failed? The key factor regarding investigation of screw loosening is the assessment of whether a screw is loosened or not, which is traditionally based on radiological approaches [3]. Our study reported a 33% loosening rate according to mechanical measurement of extraction torque during instrumentation removal surgery. I had surgery on May 2, 2012. surgeon put in plate and four screws.I have been having pain again now for about a month or little more. If such findings are detected, a second operation for revision should be considered as soon as possible to prevent potentially fatal complications. I also get extremely achy in this area. Now I know why! Dysphagia after anterior cervical discectomy and fusion (ACDF) is common, with a prevalence ranging between 28% and 57% of cases. Pedicle screw loosening: the value of radiological imagings and the identification of risk factors assessed by extraction torque during screw removal surgery, Journal of Orthopaedic Surgery and Research, https://doi.org/10.1186/s13018-018-1046-0, http://creativecommons.org/licenses/by/4.0/, http://creativecommons.org/publicdomain/zero/1.0/. My doctor says the fusion did not take. xray of the offending foot showed the screw is on the move. If you no longer reside in the area, youll want to connect with an experienced spine surgeon near you. Spine. Damaged hardware may be replaced or additional hardware may be inserted to ensure healing takes place as expected and so your spine can handle any future stress your body may put on it. The fusion of the vertebrae in the lower back can be used to alleviate pain and degeneration from a variety of low back conditions. In addition to chronic back pain, other symptoms of failed back surgery include neurological symptoms (eg, numbness, weakness, tingling sensations), leg pain, and radicular pain (pain that spreads from one area of the body to another, such as from your neck down to your arm). I just had another MRI today and I now have more problems. OK so I overdid it and after months of pain and test had to undergo another fusion of the level above. Wu JC, Huang WC, Tsai HW, Ko CC, Wu CL, Tu TH, Cheng H. Pedicle screw loosening in dynamic stabilization: incidence, risk, and outcome in 126 patients. If any pain is still remaining, then that too will continue to get lesser gradually. Other factors that could cause bone loss or destruction, such as infection surrounding the implant, bone tumor, metabolic diseases, and microfracture due to excessive loading, are risk factors of pedicle screw loosening. used both CT scan and X-ray to assess screw loosening, and their results showed that CT scan was significantly more sensitive than X-ray [11]. No pain meds. If after 6-12 months a patient continues to have or experience new pain, more imaging may be pursued. It was observed in one case that CT scan failed to show a clear gap around screw, even though an obvious double halo was found on X-ray and the extraction torque was 0.06Nm (Fig. Due to inadequate exposure of screw and malfunction of screw tail, 6 screws had no reading of extraction torque. Rods, screws and plates are all co. 651-219-7292 . Spinal fusion is a time-tested surgical approach to many types of chronic spine-related pain, especially in the neck and lower back. The distribution of screws in three clusters based on extraction torque by Twostep Cluster. It's a pain like sciatica: a sharp stabbing pain that runs in a thin band down your leg. There was no significant difference regarding the diameter or length of screws as shown in Fig. Heres what you should know about spine deformities that can develop during the adult years. | Mehta Spine. Easy for him to say I guesss. Hi, I had spinal fusion done L4-5 back in 2001. 3f, g. Analyzing risk factors for low extraction torque of pedicle screw. demonstrated endoscopic extrusion of a screw after anterior cervical disc fusion, which caused esophageal perforation . Personal Stories. Bones fail to fuse. Scoliosis surgery involves fusing the most-tilted vertebrae of the spine into one solid bone to prevent further progression, not to correct the abnormal spinal curvature. The authors declare that they have no competing interests. The worst of the pain begins to subside by four weeks after the spinal fusion surgery. *p<0.001, Kruskal-Wallis test. I am still very conscious of the incision site and the feeling of the muscles and hardware in my back. lol I'm trying to be hopeful that this will at least alleviate most of my pain. 1997;79(2):1839. Persistent Pain The University of Maryland Spine Center states that the most common complication of lumbar fusion surgery is persistent pain 3. What Can I Expect After A Spinal Fusion? It reduces the range of motion of the stabilized spine, increases the fusion rate, and is generally considered to be safe with relatively low complication rate associated with the device [1, 2]. Success rates vary depending upon the parameters examined. Chronic back pain. Screws inserted in the lumbosacral junction (L4, L5, and S1) showed the highest torque. In todays blog, we take a closer look at what to expect if your spinal hardware breaks or shifts. The mean torque of screws placed in the lumbosacral junction (L4, L5, and S1, n=54) was 2.141.12Nm, which was significantly higher than those placed in other segments. Spine deformities are a surprisingly common cause of adult back pain, and even a subtle change in your spine curvature can cause problems. If pedicle screws loosen, it may result in new or worsening back pain, leading to failed back surgery syndrome (FBSS). I had two back surgeries and left to travel for two yrs only to come back to Fla. to see my neurosurgeon. Anecdotally, I have wondered if some loose screws occurred due to persistent wobbling of the screw in the bone. Therefore, the actual circumstances of pedicle screw loosening are not acknowledged due to the various diagnostic criteria and conflicting reports. Faraj AA, Webb JK. I am going through some life altering pain and will not see him again till Dec.1,2011. The possible signs of a failed fusion include chronic back pain, reduced mobility, neuropathic pain, and radicular pain. Is it possible for a screw to come loose? 1998;23(12):13749. But opting out of some of these cookies may affect your browsing experience. Spinal fusion in simple words can be defined as the process where bone problems experienced in the spine can be corrected. Mid-range outcomes in 64 consecutive cases of multilevel fusion for degenerative diseases of the lumbar spine. Hi, I broke c2 c3 c4 and c5 in my neck and T6 thoratic spine last august Hey All. Surgeons need to be more cautious when assessing screw loosening based on radiological examination, since a considerable fraction of low extraction torque screws might have been underestimated. Why is a screw not good for MDF? If you have these symptoms, your surgeon may perform imaging tests to see problems in your hardware. Significant difference was found between different segments (p<0.001) as shown in Fig. Your surgeon will normally re-open your original incision. The effects of pedicle screw fit. If the spinal cord is injured, complete loss of bowel and bladder function could occur. These cookies track visitors across websites and collect information to provide customized ads. procedure, the risk of pseudarthrosis after ACDF is an important complication, similar to that seen after lumbar spine fusions. He could feel it, which is kind of freaky. Normal movement places small stresses on normal bones, which can actually flex a tiny bit; but motion also stresses the hardware, which is rigid - that's the point of putting it in; and since the metal won. How you prepare This can give more stability to the entire spine. Causes and Risk Factors Smoking Formation of scar tissue Recurring or persistent disc disease at adjacent levels Continued pressure from spinal stenosis Instability or abnormal movement Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. Revision pedicle screws. These include excessive bleeding, reactions to drugs or anesthesia or formation of blood clots in vessels that might break free and damage organs, including the lungs. The relatively low related coefficients might be due to the existence of numerous confounding factors, and these results indicated that the failure risk of instrumentation increased with age and osteopenia/osteoporosis, which was widely credited but rarely proven in vivo with mechanical measurement. Pain and swelling after spinal fusion surgery. Further study with larger simple size is needed to confirm the effect of screw length and diameter on extraction torque in the human spine. Although major loss of the strength and sensation to the legs or loss of bowel or bladder control can occur, it is rare. The screw, especially a larger diameter screw, is acting like a wedge so the board can actually be split apart around the screw. If your fusion has not been successful they may put new hardware in its place. Surgery in L5 S1 Fusion is denoted by its level. I have no pain from those cages at all. If after 6-12 months a patient continues to have or experience new pain, more imaging may be pursued. Eur Spine J. Inter-observer reliability of detecting Dynesys pedicle screw using plain X-rays: a study on 50 post-operative patients. The primary objective was to study the prevalent of pedicle screw loosening according to extraction torque during screw removal surgery and access the sensitivity and specificity of both X-ray and CT scan for diagnosing screw loosening. Injury to blood vessels or nerves in and around the spine. Like, the doctor has to pretty much blatantly screw up. Rods, screws and plates are all common forms or hardware that are inserted, and while they are quite durable, they arent a perfect solution. Spinal tumors all affect the spine, but they can happen in different ways and cause different symptoms. My new doctor redid the first surgery, but now one year after surgery my L5 screws are loose again. The cookie is used to store the user consent for the cookies in the category "Performance". These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. If you have had a lumbar fusion, then there is always the risk of a hardware malfunction, failure or breakage. J Bone Joint Surg Br. Your vertebrae are the bones that make up your spine (backbone). Return of symptoms. More specifically, for 1, 2, and 3-level fusion, the fusion rates are 88-90%, 73-80%, and 70%, respectively30,31. Symptoms Of Loose Screws After Spinal Fusion The most common type of pedicle screw used in spinal surgeries is known to loosen or break over time. Have you gotten a second opinion regarding the first surgery and the proposed plan for this time around? Postsurgical Complications Surgeries always carry a risk for infection, which can vary by institution. I am sorry for what you are going through. Xiaoliang Wu and Jiawei Shi contributed equally to this work. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. A comparative study on screw loosening in osteoporotic lumbar spine fusion between expandable and conventional pedicle screws. One hundred thirty of them were polyaxial and 106 were monoaxial. Loosening of instrumentation frequently occurs when the bones of the spine dont heal or fuse correctly; this poor healing my also cause hardware to shift or break. This is why I often limit my patients activities and often apply braces. Meanwhile, the strain imposed on pedicle screws might significantly increase when fusion had not been obtained or anterior column support was inadequate. L2, at that time he took out all my old hardware, "since i am there" was the answer i was told why they took it out. They have to show doctor error or malice in order to make a law suit. These are common problems after spinal fusion that people suffering from spinal pain must know about. Meanwhile, by using extraction torque data, we analyzed the risk factors of screw loosening. I recently did something that caused full blown sciatica. Most spinal fusions use a bone graft to fuse or join two vertebrae. What can't you do after spinal fusion? Pedicle screw loosening: the value of radiological imagings and the identification of risk factors assessed by extraction torque during screw removal surgery. (L3-5) stabilization system and in whom the left L-5 pedicle screw broke (B, arrow) 24.5 months after surgery without clinical symptoms. 11 4 Related questions Surgeons needed to be more cautious when assessing screw loosening merely according to radiological examination, and aware of that screws in fractured vertebrae or non-fusion surgery were vulnerable to loosening. Herniated discs are a common cause of back and neck pain, with symptoms limiting activities and even interfering with getting a good nights sleep. However, the actual fusion does not occur for at least the next 6-12 months, which is the second part. Based on the torque data, the loosening rate was 33%, while both X-ray and CT scan only detected less than 30% of all loosening screws. I consider the analogy of a screw placed in a wall. Regarding extraction torque, there was no significant difference between polyaxial and monoaxial screws (p=0.673) as shown in Fig. CT scan was also employed by some studies and considered the diagnostic imaging modality of choice for detection of screw loosening [4, 9, 11, 12]. Provided by the Springer Nature SharedIt content-sharing initiative. An epidural catheter (a thin, flexible tube) may be inserted into the back at the conclusion of the operation to help control pain. Springer Nature. Jianting Chen or Hui Jiang. It should be noted that this does not indicate these patients had any infection the patients studied did not show any infection whatsoever. Patient satisfaction is low. There was no linear correlation between extraction torque and patients height (p=0.848), weight (p=0.196), BMI (p=0.125), and time interval between the primary surgery and screw removal surgery (p=0.965). 2023 BioMed Central Ltd unless otherwise stated. Cookies policy. The cookie is used to store the user consent for the cookies in the category "Analytics". Right Posture to Escape & Avoid Neck Pain. Can barely lift them to walk, can't stand up from a chair without assistance. hardware removed after a spinal fusion - shared with permission. Christensen FB, Dalstra M, Sejling F, Overgaard S, Bunger C. Titanium-alloy enhances bone-pedicle screw fixation: mechanical and histomorphometrical results of titanium-alloy versus stainless steel. X-ray had a sensitivity of 24% and a specificity of 98%, while CT scan had a sensitivity of 22% and a specificity of 96%. While the mean torque of loosened screws diagnosed by CT was 1.031.00Nm, which was also significantly lower (p=0.008) than others (1.711.00Nm). The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. 2009;33(6):16838. This website uses cookies to improve your experience while you navigate through the website. Traditionally, it was assessed by radiological approaches, both X-ray and CT (computed tomography) scan, while reports using mechanical method to study screw loosening after spine surgery are rare. However, many patients continue to experience pain up to three to six months of surgery as well. Even loose screws should be noted in follow-up X-ray studies. Rollinghoff M, Schluter-Brust K, Groos D, Sobottke R, Michael JW, Eysel P, Delank KS. Therefore, we set our cut-off torque at 1.02Ncm for screw loosening. Acta Orthop Scand. The indications for screw removal included the following: (1) pedicle screw fixation for thoracolumbar fracture without fusion and imaging confirmed solid fracture union, (2) patients required screw removal that presented persistent axial para-midline back pain to palpation or abnormal foreign body sensation due to pedicle fixation with imaging confirmed solid fusion, and no other cause found, e.g., infection. 2005;10(2):1336. Wu et al. . Meanwhile, we compared our extraction torque data with X-ray and CT scan findings, the result showed that the specificity of both imaging approaches were excellent, and the peri-screw osteolysis present both in X-Ray and CT scan could indicate low extraction torque of screw anchor, but their sensitivities were less than satisfactory (24% and 22% respectively), regarding detection of screw loosening. This type of pain is called neurogenic or neuropathic pain. p=0.673, Mann-Whitney Test. It does not store any personal data. How To Relieve Back Pain From Standing Too Long? Naturally, there are some risks associated with the surgery. References A possible explanation could be that surgeries performed in lumbosacral spine were mainly for degenerative disc diseases, which often required spinal fusion, while in the thoracolumbar spine, where operations were more likely for vertebral fracture, fusion were not always necessary. The same surgeon (J.S. These are few things to keep in mind whenever an individual opts for spinal fusion surgery. These cookies will be stored in your browser only with your consent. Bleeding. Possible complications include: Infection. J Orthop Surg Res 14, 6 (2019). What are the physical state of oxygen at room temperature? 3c. Botolin S, Merritt C, Erickson M. Aseptic loosening of pedicle screw as a result of metal wear debris in a pediatric patient. senior attending doctor), who was blinded to the extraction torque and patient information. What happens to atoms during chemical reaction? The reasons that no significant different extraction torque was found among screws with different length and diameter might be due to the relatively small sample size and narrow range of length (3055mm) and diameter (4.06.5mm). p=0.01, R2=0.267, F=8.296, Linear regression analysis, Scatter diagram of patients average torques and ages. Hence, further studies with larger sample size and stratified data according to different factors will be needed to better understand the prevalent of pedicle screw loosening. Once they have a diagnosis, they can begin developing a treatment plan. Lumbar fusion permanently stops movement between two vertebrae. A nurse will take you through the hospital admissions and discharge procedures. Orthop Rev. We also found that pedicle screws in the lumbosacral junction (L4, L5, and S1) had significant higher extraction torque than those in other segments. A rogue screw or rod can interfere with the spine's surrounding structures (the muscles, vertebrae, and nerves), which can cause serious pain and nerve damage if . I do have a doctor appt next week, but previously was told my CT scan showed the fusion is solid. So nerve damage during the operation is the first cause of severe leg pain after a spinal fusion. When this separation occurs, then the screw is held by these loose, torn fibers which do not have a lot of strength, as you might imagine. Hardware (such as screws, rods, or cages) may break and/or become loose; Bleeding; Signs and symptoms of other complications include. Spine J. Spinal hardware is used in a number of different procedures to help increase stability or facilitate healing after an injury. 3b. Sanden [20] reported a 64% sensitivity of X-ray in 79 screws and a 35% rate of screw loosening, but their definition of a loosed screw was an extraction torque of 0.4Nm or less as there were no screws with and extraction torque between 0.4Nm and 0.75Nm. c Screw placed in fractured vertebrae showed significantly lower extraction torque than those in non-fractured vertebrae. Normal spinal alignment preserved. In the last 6 years I've had 5 back surgeries. p=0.746, Kruskal-Wallis test. Ohtori et al. The doctor could actually trigger the pain by touching where the lower screws are in my back. Villa T, La Barbera L, Galbusera F. Comparative analysis of international standards for the fatigue testing of posterior spinal fixation systems. Meanwhile, stress shielding can lead to a decrease of stress transferred through the bone tissue, which can reduce bone mineral density and remodel the bone surrounding the screw. As expected, linear regression analysis showed that the stability of pedicle screw correlated positively with BMD and negatively with patients age. Are there some people who "reject" the hardware that is in their body or does it definitely mean the fusion surgery has to be redone. J Neurosurg Spine. Heres what to eat and what to leave out of your pre-surgery diet. In both cases the pedicle screws were terribly misplaced,. Spinal fusion often involves placing metal screws with rods or plates to immobilize bones and allow them to fuse, or grow together. In this case, it might be possible to take legal action against the doctor, surgeon or hospital that was responsible for your surgery. Causes of Post-laminectomy Syndrome Frequent causes include returning disc herniation and nerve root compression. Blood clots. I have a doctor's appt Monday morning. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The main role of the screw in lumbar fusion is to reduce the motion of the spine and to conduct the stabilization, whereas screw loosening is observed in quite a few literature works (7)(8)(9). There are several occasions when spinal fusion can be required or suggested by the doctor when the patient might be experiencing disk related problems, deformities such as curvature of the spine, or even spinal weakness. However, it could indicate failed fusion or pseudoarthrosis. What are the signs that a surgical screw is coming loose? Heres how. If you have doubts, ask for x-Ray or MRI to confirm the placement of hardware. Schizas C, Tzinieris N, Tsiridis E, Kosmopoulos V. Minimally invasive versus open transforaminal lumbar interbody fusion: evaluating initial experience. This may suggest that spine screws could prophylactically be coated with antibiotic material prior to implantation, to help aid in fusion and surgical success. 1994;19(15):17528. Spine. Wu, X., Shi, J., Wu, J. et al. . The screws were clustered into three clusters based on torque by Twostep Cluster as shown in Fig. The incidence of ACDF has been reported between -50%23-29. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. They think they are God and that back surgery is an easy fix. e Extraction torques of pedicle screw after fusion surgery (n=142) were significantly higher than those in non-fusion surgery. Additionally, the patient's ability to complete activities of daily living may be altered. Therefore, we intended to investigate the pedicle screw loosening rate using extraction torques during instrumentation removal surgery, and compare it with X-ray and CT image findings. Can loosening screws in spine fusion be dangerous? We also use third-party cookies that help us analyze and understand how you use this website. Never stopped smoking but was coming along good. [17] reported higher occurrence of screw loosening in osteoporotic bone. During this first appointment, theyll ask about your symptoms, conduct a physical exam and have you perform some movements if you are able. This may include facet joint or sacroiliac joint rhizotomy, spinal fusion, or sacroiliac joint fusion. Spine J. A recent article has potentially identified a novel hypothesis bacteria. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. This cookie is set by GDPR Cookie Consent plugin. Understanding the Spinal Fusion Procedure The goal of spinal fusion is to connect adjoining vertebrae by using techniques developed from researching the actual healing process that broken bones undergo. A few hundred screws were analyzed after being removed in revision surgeries. Do Chiropractic Adjustments Work Long-Term, What is Tech Neck? 2 doctor answers 3 doctors weighed in. The maximum extraction torque was recorded while unscrewing the screw using torque gauge with a range of 0.06 to 6.00Nm (Park Tool, China). What is the treatment for failed back surgery syndrome? CAS Necessary cookies are absolutely essential for the website to function properly. pain and redness in your lower legs that might extend above your knee chest pain a cough shortness of breath Symptoms of an infection include: severe pain fever chills redness and swelling and. 1993;18(15):22318 discussion 2238-2239. Started today, and hope its something that wont require surgery. Spinal fusion surgery might also be performed when a patient has: Fractured (broken) bones from a traumatic injury Abnormal curvatures of the spine from conditions like scoliosis An unstable or weak spine due to tumors or infections Degenerative disc disease resulting in mechanical back pain The debris elicited an inflammatory cytokine-mediated particulate-induced response through increased expression of intracellular TNF-alpha, increased osteoclastic activity, and cellular apoptosis. Symptoms The main symptom is pain following back surgery. Its an occasional thing if the metalware has been in for a while, which is unusual because most hardware is removed after about three months. Spinal nerve damage that can result in weakness, pain, loss of sensation, and loss of bowel or bladder control The vertebrae above and below the fusion are more likely to wear away, leading to more problems later Leakage of spinal fluid that may require more surgery Headaches Bleeding and blood clots 3d. Anterior plate well applied. Therefore, the reading of extraction torque was taken in 226 screws. The mean torque of screws placed in fractured vertebrae was 1.030.63Nm, which was significantly lower (p=0.009) than those in non-fractured vertebrae, as shown in Fig. The first thing theyll do is request that you set up an initial appointment so that they can get to the bottom of your issue. Pedicle screws are placed above and below the vertebrae that were fused. Furthermore, the sensitivity and specificity of the X-ray criteria of loosening could be confounded by many factors, such as metal image artifact, intestinal gas, and display angle. 5 Is it possible for a screw to come loose? *p=0.009, Mann-Whitney Test. It can have associated numbness, tingling and weakness in your leg. In general, both X-ray and CT scan lack uniform and explicit standard. We constructed a linear regression model with Pearson correlations analysis to assess whether clinical data, such as age and BMD, were correlated with the extraction torque of screw. But in many cases, it can be because of negligence. Regardless, the nerve root can take a long time to heal from a fusion surgery, making the outcome difficult to predict. What are the Treatments for Failed Back Surgery Syndrome? The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". https://doi.org/10.1186/s13018-018-1046-0, DOI: https://doi.org/10.1186/s13018-018-1046-0. The x rays showed a halo around the screw. Linear regression analysis was used to estimate the relevance between the extraction torque of pedicle screw and other clinical findings. A selected survey of ABS members. Informed consent was obtained from all individual participants included in the study.