Richard Guyer - Academia.edu (original) (raw)
Papers by Richard Guyer
![Research paper thumbnail of [CONFERENCE ABSTRACT] Radiographic Comparison of Two Lumbar Total Disc Replacement Devices: Results from a Prospective, Randomized, Controlled Multicenter FDA-Regulated Trial (#27)](https://attachments.academia-assets.com/46602971/thumbnails/1.jpg)
](The Spine Journal, Aug 2010
BACKGROUND CONTEXT: Current total disc replacements (TDRs) are designed for implantation using an... more BACKGROUND CONTEXT: Current total disc replacements (TDRs) are designed for implantation using an anterior approach. This has led to concern about the safety of re-operation if a device needs to be removed or revised. PURPOSE: The purpose of this study was to determine the incidence of re-operation using an anterior approach in TDR patients and identify complications encountered in such procedures. STUDY DESIGN/SETTING: Adverse event and surgery logs were reviewed to identify patients who underwent re-operation through an anterior approach after lumbar TDR. All patients were from a single spine specialty center. PATIENT SAMPLE: Thirteen patients, from a consecutive series of 1,000 accumulated over a period of almost 10 years, were identified who underwent re-operation with an anterior approach. All had undergone lumbar TDR for the treatment of painful disc degeneration unresponsive to non-operative care. OUTCOME MEASURES: The primary outcome measure was the occurrence of a revision TDR surgery using an anterior approach. The reason for the re-operation and any complications associated with it were recorded. METHODS: FDA IDE study records and surgery logs were reviewed for all patients who underwent lumbar TDR. Records of re-operated patients were reviewed and those who underwent a second anterior approach were included in this study. RESULTS: In 13 patients (1.3% of 1,000 TDR cases performed), was repeat anterior spinal surgery undertaken. Reasons for re-operations included: malpositioned polyethylene core (n51), vertebral body fracture (n51), revision to a smaller TDR device (n51), reaction to metallic implant (n52), device migration or loosening (n53), segmental instability (n51), and ongoing pain (n54). In six cases, the device had spikes for anchoring , and seven had keels. In all 13 patients, the planned re-operation was executed without complication. A summary of the cases and the re-operations is provided in the table. CONCLUSIONS: A large case series, including the learning curves of ten spine surgeons, demonstrates that anterior re-operation following TDR is rarely needed (approximately 1%). When needed, it can be performed safely. Caution and careful planning should be exercised when undergoing a repeat anterior approach. The planning of such surgery needs to take into consideration the structural integrity of the anterior spinal column.
The Spine Journal, 2003
In the last few years, the strategic plans of many medical organizations have emphasized the impo... more In the last few years, the strategic plans of many medical organizations have emphasized the importance of networking. Interaction with other medical organizations that have similar interests and agendas serves several purposes: it maximizes exposure for all organizations, it streamlines advocacy activities and it stimulates the delivery of the highest quality health care.
Plano, TX) 167 decompression/ fusion patients where increased surgical time and intraoperative fl... more Plano, TX) 167 decompression/ fusion patients where increased surgical time and intraoperative fluids were correlated with delayed extubation. 1 REFERENCES: 1. Kwon B, Yoo JU, Furey C, Rowbottom J, Emery SE: Postoperative airway management after single-stage, multi-level anterior cervical decompression and posterior fusion: risk factors of delayed extubation.
Spine
Patients who suffer from persistent pain for prolonged periods of time (6 months or more) are oft... more Patients who suffer from persistent pain for prolonged periods of time (6 months or more) are often influenced to an increasing extent by psychological factors. Patients begin to focus on their pain as the problem rather than its physical origin. This study evaluated the effectiveness of sensory deprivation in reducing pain in patients with chronic low-back pain. Sixty patients were divided into two groups of 30 patients each: One group underwent 1 hour of sensory deprivation; the other received a lecture on relaxation skills. In the group receiving sensory deprivation, statistically significant decreases in pain and stiffness were noted. Sensory deprivation is an effective treatment to reduce pain and thus interrupt the pain cycle in patients with chronic low-back pain.
Current Opinion in Orthopaedics
Spine
The possibility of a relationship between discographic pain responses and Minnesota Multiphasic P... more The possibility of a relationship between discographic pain responses and Minnesota Multiphasic Personality inventory scores was investigated. To determine if patients with elevated Minnesota Multiphasic Personality Inventory scale scores were more likely to report pain on the injection of a nondisrupted disc than were patients without such high scores. In general, injection into disrupted discs provokes pain, whereas injection into nondisrupted discs does not. However, discordant results are sometimes obtained and create a more difficult diagnostic challenge. The primary study group was composed of 72 patients who underwent computed tomography/discography at the three lowest lumbar levels for diagnostic purposes and completed the Minnesota Multiphasic Personality Inventory. The mean scores on the Minnesota Multiphasic Personality Inventory hypochondriasis and hysteria scales were significantly greater for patients reporting reproduction of clinical pain than for patients not reporting pain on injection of a nondisrupted disc (hypochondriasis: 77.2 vs. 68.6, P < 0.01; hysteria: 74.5 vs. 68.3, P < 0.05). The scores on the depression scale followed a similar trend (68.6 vs. 63.6, P < 0.15). Multivariate analysis, adjusting the means for possible confounding effects of age, symptom duration, and sex, did not alter the results. Discographic pain reports are not only related to anatomic abnormalities, but are influenced by personality as assessed by the Minnesota Multiphasic Personality Inventory. Patients with elevated scores on the hypochondriasis, hysteria, and depression scales may tend to overreport pain during discographic injection. Among such patients, even those with a concordant computed tomography/discographic image, selection of therapeutic modalities should be made with caution.
Spine, 2015
This was a prospective, randomized, controlled, multicenter study. The purpose of this study was ... more This was a prospective, randomized, controlled, multicenter study. The purpose of this study was to compare outcomes of two lumbar total disc replacements (TDR)s at 5-year follow-up and report results of serum ion level analysis in a subgroup of patients receiving a metal-on-metal implant. Lumbar TDR has been compared with fusion in several randomized studies, finding TDR non-inferior to fusion and superior on some measures. Receiving less attention has been comparing TDR devices. Additionally, there is concern about metal-on-metal implants, with little data available for spine devices. The study included 204 patients receiving Kineflex-L (Investigational) and 190 receiving Charité (Control). Outcome measure included Oswestry Disability Index (ODI), visual analog pain scales (VAS), patient satisfaction, neurological status, complications, reoperations, and a composite success score. Radiographic assessment included range of motion, subsidence, and heterotrophic ossification. In 32 I...
The Spine Journal
EMG screw testing has been shown to be sensitive and reliable in open spinal instrumentation case... more EMG screw testing has been shown to be sensitive and reliable in open spinal instrumentation cases. However, there is little evidence to show its applicability to percutaneous screw placement. To demonstrate the utility of EMG testing in percutaneous techniques, where lack of direct visualization poses an added risk to nerve injury. Summary of intraoperative EMG results during percutaneous pedicle screw placement. Percutaneous pedicle screws were placed in twenty patients (22 levels, 88 pedicles). The initial fluoroscopically-guided k-wires and the subsequent taps were insulated and stimulated via an automated EMG system. Low threshold values prompted repositioning of the pedicle trajectory. Four (5%) k-wires induced EMG thresholds less than 10mA, prompting repositioning. One was repositioned without improvement, but with improvement upon tapping. One k-wire with very low threshold (3mA) was repositioned with an improved result (13mA). In 78 pedicles (89%) the tap threshold was greater than the k-wire. EMG testing helps to identify suboptimal screw trajectories, allowing for early adjustment and confirmation of improved placement. Tapping often improved thresholds, perhaps by compressing the bone and creating a denser, more insulative pedicle wall. EMG testing may improve the safety of percutaneous screw techniques, where the pedicle cannot be visually inspected.
The Spine Journal
BACKGROUND CONTENT: This is a synopsis of a symposium presented to the North American Spine Socie... more BACKGROUND CONTENT: This is a synopsis of a symposium presented to the North American Spine Society Annual Meeting in Seattle, WA, 2001. To bring to the reader who may not have attended the symposium a distillation of the material presented on this frontier of spinal surgery. Panel presentation. The proposed indication for artificial disc replacement is a degenerated but contained disc, painful to the point of major life-style interruption, refractory to at least 1 year of nonoperative treatment, preferably at a single lumbar level and without infection, listhesis or major facet joint disease or spinal stenosis. Total disc replacements have been developed and used mostly in Europe. Disc nucleus replacements have also been developed. No disc replacement has been approved for general use in North America as yet. The US Food and Drug Administration is conducting investigational device exemption studies at this time. Artificial disc replacement is not a new concept, the first attempts h...
![Research paper thumbnail of [EDITORIAL RESPONSE] Lumbar disc arthroplasty compared with interbody fusion](https://attachments.academia-assets.com/40522117/thumbnails/1.jpg)
](Journal of neurosurgery. Spine
Seminars in Spine Surgery, 2012
ABSTRACT Lumbar total disk replacement (TDR) has been used for the treatment of painful disk dege... more ABSTRACT Lumbar total disk replacement (TDR) has been used for the treatment of painful disk degeneration since the 1980s. Not until the Food and Drug Administration (FDA) regulated trials in the United States initiated in 2000 had there been formal prospective randomized trials evaluating the results of this technology compared with fusion, the traditional surgical treatment for disk degeneration. The purpose of this article was to provide a commentary on the results of the 5-year follow-up of CHARITÉ artificial disk (DePuy Spine, Raynham, MA) published by Guyer et al (Spine J 9:374-386, 2009) and to comment on this work in the context of other TDR literature. In the study, results of TDR using the CHARITÉ artificial disk, were compared with those of anterior lumbar interbody fusion (ALIF) with BAK cages and iliac crest autograft, for the treatment of single-level degenerative disk disease from L4 to S1. The results of the 5-year, prospective, randomized multicenter study were consistent with the 2-year outcomes. The TDR group had improved functional outcomes based on visual analog pain scales, Oswestry Disability Index, and the SF-36 Physical component scores. CHARITÉ patients reached a greater rate of part- and full-time employment and a statistically lower rate of long-term disability compared with ALIF patients. Radiographically, the range of motion at the index and adjacent levels was maintained. The incidence of adjacent level degeneration was lower for TDR than in the fusion group. The results of this study indicate that TDR with the CHARITE produced results similar or superior to ALIF at 5-year follow-up.
Seminars in Spine Surgery, 2007
ABSTRACT
Surgery for Low Back Pain, 2010
ABSTRACT Today, we have many surgical options for treating symptomatic degenerative disc disease ... more ABSTRACT Today, we have many surgical options for treating symptomatic degenerative disc disease for those patients who fail adequate non-operative treatment. Though many of these technologies are new, they need to pass the test of time with positive objective outcome measures. There has been two decades of experience with TDR in Europe, with good results generally reported, even in studies with more than 10-year follow-up. Randomized trials in the United States have provided a direct comparison to fusion with TDR and found TDR to be as effective as fusion, or more effective on some parameters. In the ideal world where economics was not an issue, the surgeon would have many more options to offer their patients with advancing technology. For the earliest stages of symptomatic disc degeneration, other motion preservation surgeries will suffice, but for the more advanced degeneration, TDR with the ensuing first generation and now second generation will offer our patients more options instead of the traditional fusion. I believe, with newer designs of TDR and in combination with posterior reconstruction, fusion for painful disc degeneration will be restricted to fewer and fewer patients.
Orthopaedic review
Recently, there has been increased interest in less invasive spinal surgery techniques. This has ... more Recently, there has been increased interest in less invasive spinal surgery techniques. This has led to the development of procedures such as automated percutaneous lumbar discectomy and arthroscopic microdiscectomy. Lasers are now used in many areas of medicine and may have applications in minimally invasive spinal surgery. A number of different laser systems have been evaluated for their effectiveness in removing disc tissue in the laboratory, but technical problems have limited their clinical use. Only the Nd:YAG (1,064 nm and 1,320 nm) and KTP (532 nm) systems have been used clinically. Unsuccessful clinical results were obtained with the 1,064 nm Nd:YAG, whereas the other two systems appeared to produce results similar to the present mechanical systems but required less time for disc removal. This paper discusses considerations for choosing a laser system for spinal applications and reviews the work performed in this area.
Orthopaedic review
The technique for lumbar discography is not well standardized. To better understand lumbar pathol... more The technique for lumbar discography is not well standardized. To better understand lumbar pathology, we have developed a consistent, reproducible, and relatively simple procedure for lumbar discography. We describe our technique and discuss variables that may differ among individual lumbar discography procedures.
The Spine Journal, Aug 2010
BACKGROUND CONTEXT: Current total disc replacements (TDRs) are designed for implantation using an... more BACKGROUND CONTEXT: Current total disc replacements (TDRs) are designed for implantation using an anterior approach. This has led to concern about the safety of re-operation if a device needs to be removed or revised. PURPOSE: The purpose of this study was to determine the incidence of re-operation using an anterior approach in TDR patients and identify complications encountered in such procedures. STUDY DESIGN/SETTING: Adverse event and surgery logs were reviewed to identify patients who underwent re-operation through an anterior approach after lumbar TDR. All patients were from a single spine specialty center. PATIENT SAMPLE: Thirteen patients, from a consecutive series of 1,000 accumulated over a period of almost 10 years, were identified who underwent re-operation with an anterior approach. All had undergone lumbar TDR for the treatment of painful disc degeneration unresponsive to non-operative care. OUTCOME MEASURES: The primary outcome measure was the occurrence of a revision TDR surgery using an anterior approach. The reason for the re-operation and any complications associated with it were recorded. METHODS: FDA IDE study records and surgery logs were reviewed for all patients who underwent lumbar TDR. Records of re-operated patients were reviewed and those who underwent a second anterior approach were included in this study. RESULTS: In 13 patients (1.3% of 1,000 TDR cases performed), was repeat anterior spinal surgery undertaken. Reasons for re-operations included: malpositioned polyethylene core (n51), vertebral body fracture (n51), revision to a smaller TDR device (n51), reaction to metallic implant (n52), device migration or loosening (n53), segmental instability (n51), and ongoing pain (n54). In six cases, the device had spikes for anchoring , and seven had keels. In all 13 patients, the planned re-operation was executed without complication. A summary of the cases and the re-operations is provided in the table. CONCLUSIONS: A large case series, including the learning curves of ten spine surgeons, demonstrates that anterior re-operation following TDR is rarely needed (approximately 1%). When needed, it can be performed safely. Caution and careful planning should be exercised when undergoing a repeat anterior approach. The planning of such surgery needs to take into consideration the structural integrity of the anterior spinal column.
The Spine Journal, 2003
In the last few years, the strategic plans of many medical organizations have emphasized the impo... more In the last few years, the strategic plans of many medical organizations have emphasized the importance of networking. Interaction with other medical organizations that have similar interests and agendas serves several purposes: it maximizes exposure for all organizations, it streamlines advocacy activities and it stimulates the delivery of the highest quality health care.
Plano, TX) 167 decompression/ fusion patients where increased surgical time and intraoperative fl... more Plano, TX) 167 decompression/ fusion patients where increased surgical time and intraoperative fluids were correlated with delayed extubation. 1 REFERENCES: 1. Kwon B, Yoo JU, Furey C, Rowbottom J, Emery SE: Postoperative airway management after single-stage, multi-level anterior cervical decompression and posterior fusion: risk factors of delayed extubation.
Spine
Patients who suffer from persistent pain for prolonged periods of time (6 months or more) are oft... more Patients who suffer from persistent pain for prolonged periods of time (6 months or more) are often influenced to an increasing extent by psychological factors. Patients begin to focus on their pain as the problem rather than its physical origin. This study evaluated the effectiveness of sensory deprivation in reducing pain in patients with chronic low-back pain. Sixty patients were divided into two groups of 30 patients each: One group underwent 1 hour of sensory deprivation; the other received a lecture on relaxation skills. In the group receiving sensory deprivation, statistically significant decreases in pain and stiffness were noted. Sensory deprivation is an effective treatment to reduce pain and thus interrupt the pain cycle in patients with chronic low-back pain.
Current Opinion in Orthopaedics
Spine
The possibility of a relationship between discographic pain responses and Minnesota Multiphasic P... more The possibility of a relationship between discographic pain responses and Minnesota Multiphasic Personality inventory scores was investigated. To determine if patients with elevated Minnesota Multiphasic Personality Inventory scale scores were more likely to report pain on the injection of a nondisrupted disc than were patients without such high scores. In general, injection into disrupted discs provokes pain, whereas injection into nondisrupted discs does not. However, discordant results are sometimes obtained and create a more difficult diagnostic challenge. The primary study group was composed of 72 patients who underwent computed tomography/discography at the three lowest lumbar levels for diagnostic purposes and completed the Minnesota Multiphasic Personality Inventory. The mean scores on the Minnesota Multiphasic Personality Inventory hypochondriasis and hysteria scales were significantly greater for patients reporting reproduction of clinical pain than for patients not reporting pain on injection of a nondisrupted disc (hypochondriasis: 77.2 vs. 68.6, P < 0.01; hysteria: 74.5 vs. 68.3, P < 0.05). The scores on the depression scale followed a similar trend (68.6 vs. 63.6, P < 0.15). Multivariate analysis, adjusting the means for possible confounding effects of age, symptom duration, and sex, did not alter the results. Discographic pain reports are not only related to anatomic abnormalities, but are influenced by personality as assessed by the Minnesota Multiphasic Personality Inventory. Patients with elevated scores on the hypochondriasis, hysteria, and depression scales may tend to overreport pain during discographic injection. Among such patients, even those with a concordant computed tomography/discographic image, selection of therapeutic modalities should be made with caution.
Spine, 2015
This was a prospective, randomized, controlled, multicenter study. The purpose of this study was ... more This was a prospective, randomized, controlled, multicenter study. The purpose of this study was to compare outcomes of two lumbar total disc replacements (TDR)s at 5-year follow-up and report results of serum ion level analysis in a subgroup of patients receiving a metal-on-metal implant. Lumbar TDR has been compared with fusion in several randomized studies, finding TDR non-inferior to fusion and superior on some measures. Receiving less attention has been comparing TDR devices. Additionally, there is concern about metal-on-metal implants, with little data available for spine devices. The study included 204 patients receiving Kineflex-L (Investigational) and 190 receiving Charité (Control). Outcome measure included Oswestry Disability Index (ODI), visual analog pain scales (VAS), patient satisfaction, neurological status, complications, reoperations, and a composite success score. Radiographic assessment included range of motion, subsidence, and heterotrophic ossification. In 32 I...
The Spine Journal
EMG screw testing has been shown to be sensitive and reliable in open spinal instrumentation case... more EMG screw testing has been shown to be sensitive and reliable in open spinal instrumentation cases. However, there is little evidence to show its applicability to percutaneous screw placement. To demonstrate the utility of EMG testing in percutaneous techniques, where lack of direct visualization poses an added risk to nerve injury. Summary of intraoperative EMG results during percutaneous pedicle screw placement. Percutaneous pedicle screws were placed in twenty patients (22 levels, 88 pedicles). The initial fluoroscopically-guided k-wires and the subsequent taps were insulated and stimulated via an automated EMG system. Low threshold values prompted repositioning of the pedicle trajectory. Four (5%) k-wires induced EMG thresholds less than 10mA, prompting repositioning. One was repositioned without improvement, but with improvement upon tapping. One k-wire with very low threshold (3mA) was repositioned with an improved result (13mA). In 78 pedicles (89%) the tap threshold was greater than the k-wire. EMG testing helps to identify suboptimal screw trajectories, allowing for early adjustment and confirmation of improved placement. Tapping often improved thresholds, perhaps by compressing the bone and creating a denser, more insulative pedicle wall. EMG testing may improve the safety of percutaneous screw techniques, where the pedicle cannot be visually inspected.
The Spine Journal
BACKGROUND CONTENT: This is a synopsis of a symposium presented to the North American Spine Socie... more BACKGROUND CONTENT: This is a synopsis of a symposium presented to the North American Spine Society Annual Meeting in Seattle, WA, 2001. To bring to the reader who may not have attended the symposium a distillation of the material presented on this frontier of spinal surgery. Panel presentation. The proposed indication for artificial disc replacement is a degenerated but contained disc, painful to the point of major life-style interruption, refractory to at least 1 year of nonoperative treatment, preferably at a single lumbar level and without infection, listhesis or major facet joint disease or spinal stenosis. Total disc replacements have been developed and used mostly in Europe. Disc nucleus replacements have also been developed. No disc replacement has been approved for general use in North America as yet. The US Food and Drug Administration is conducting investigational device exemption studies at this time. Artificial disc replacement is not a new concept, the first attempts h...
Journal of neurosurgery. Spine
Seminars in Spine Surgery, 2012
ABSTRACT Lumbar total disk replacement (TDR) has been used for the treatment of painful disk dege... more ABSTRACT Lumbar total disk replacement (TDR) has been used for the treatment of painful disk degeneration since the 1980s. Not until the Food and Drug Administration (FDA) regulated trials in the United States initiated in 2000 had there been formal prospective randomized trials evaluating the results of this technology compared with fusion, the traditional surgical treatment for disk degeneration. The purpose of this article was to provide a commentary on the results of the 5-year follow-up of CHARITÉ artificial disk (DePuy Spine, Raynham, MA) published by Guyer et al (Spine J 9:374-386, 2009) and to comment on this work in the context of other TDR literature. In the study, results of TDR using the CHARITÉ artificial disk, were compared with those of anterior lumbar interbody fusion (ALIF) with BAK cages and iliac crest autograft, for the treatment of single-level degenerative disk disease from L4 to S1. The results of the 5-year, prospective, randomized multicenter study were consistent with the 2-year outcomes. The TDR group had improved functional outcomes based on visual analog pain scales, Oswestry Disability Index, and the SF-36 Physical component scores. CHARITÉ patients reached a greater rate of part- and full-time employment and a statistically lower rate of long-term disability compared with ALIF patients. Radiographically, the range of motion at the index and adjacent levels was maintained. The incidence of adjacent level degeneration was lower for TDR than in the fusion group. The results of this study indicate that TDR with the CHARITE produced results similar or superior to ALIF at 5-year follow-up.
Seminars in Spine Surgery, 2007
ABSTRACT
Surgery for Low Back Pain, 2010
ABSTRACT Today, we have many surgical options for treating symptomatic degenerative disc disease ... more ABSTRACT Today, we have many surgical options for treating symptomatic degenerative disc disease for those patients who fail adequate non-operative treatment. Though many of these technologies are new, they need to pass the test of time with positive objective outcome measures. There has been two decades of experience with TDR in Europe, with good results generally reported, even in studies with more than 10-year follow-up. Randomized trials in the United States have provided a direct comparison to fusion with TDR and found TDR to be as effective as fusion, or more effective on some parameters. In the ideal world where economics was not an issue, the surgeon would have many more options to offer their patients with advancing technology. For the earliest stages of symptomatic disc degeneration, other motion preservation surgeries will suffice, but for the more advanced degeneration, TDR with the ensuing first generation and now second generation will offer our patients more options instead of the traditional fusion. I believe, with newer designs of TDR and in combination with posterior reconstruction, fusion for painful disc degeneration will be restricted to fewer and fewer patients.
Orthopaedic review
Recently, there has been increased interest in less invasive spinal surgery techniques. This has ... more Recently, there has been increased interest in less invasive spinal surgery techniques. This has led to the development of procedures such as automated percutaneous lumbar discectomy and arthroscopic microdiscectomy. Lasers are now used in many areas of medicine and may have applications in minimally invasive spinal surgery. A number of different laser systems have been evaluated for their effectiveness in removing disc tissue in the laboratory, but technical problems have limited their clinical use. Only the Nd:YAG (1,064 nm and 1,320 nm) and KTP (532 nm) systems have been used clinically. Unsuccessful clinical results were obtained with the 1,064 nm Nd:YAG, whereas the other two systems appeared to produce results similar to the present mechanical systems but required less time for disc removal. This paper discusses considerations for choosing a laser system for spinal applications and reviews the work performed in this area.
Orthopaedic review
The technique for lumbar discography is not well standardized. To better understand lumbar pathol... more The technique for lumbar discography is not well standardized. To better understand lumbar pathology, we have developed a consistent, reproducible, and relatively simple procedure for lumbar discography. We describe our technique and discuss variables that may differ among individual lumbar discography procedures.