Richard G. Fessler

Comparison of BRYAN Cervical Disc Arthroplasty With Anterior Cervical Decompression and Fusion : Clinical and Radiographic Results of a Randomized, Controlled, Clinical Trial

Study Design. A prospective, randomized, multicenter study of surgical treatment of cervical disc disease. Objective. To assess the safety and efficacy of cervical disc arthroplasty using a new arthroplasty device at 24-months follow-up. Summary of Background Data. Cervical disc arthroplasty preserves motion in the cervical spine. It is an alternative to fusion after neurologic decompression, whereas anterior decompression and fusion provides a rigorous comparative benchmark of success. Methods. We conducted a randomized controlled multicenter clinical trial enrolling patients with cervical disc disease. Ultimately 242 received the investigational device (Bryan Cervical Disc), and 221 patients underwent a single-level anterior cervical discectomy and decompression and fusion as a control group. Patients completed clinical and radiographic follow-up examinations at regular intervals for 2 years after surgery. Results. Analysis of 12- and 24-month postoperative data showed improvement in all clinical outcome measures for both groups; however, 24 months after surgery, the investigational group patients treated with the artificial disc had a statistically greater improvement in the primary outcome variables: Neck disability index score (P = 0.025) and overall success (P = 0.010). With regard to implant- or implant/surgical-procedure-associated serious adverse events, the investigational group had a rate of 1.7% and the control group, 3.2%. There was no statistical difference between the 2 groups with regard to the rate of secondary surgical procedures performed subsequentto the index procedure. Patients who received the artificial cervical disc returned to work nearly 2 weeks earlier than the fusion patients (P = 0.015). Conclusion. Two-year follow-up results indicate that cervical disc arthroplasty is a viable alternative to anterior cervical discectomy and fusion in patients with persistently symptomatic, single-level cervical disc disease.

Prospective, multicenter study of spinal cord stimulation for relief of chronic back and extremity pain.

Study Design This prospective, multicenter study was designed to investigate the efficacy and outcome of spinal cord stimulation using a variety of clinical and psychosocial outcome measures. Data were collected before implantation and at regular intervals after implantation. This report focuses on 70 patients who had undergone 1 year of follow‐up treatment at the time of data analysis. Objectives To provide a more generalizable assessment of long‐term spinal cord stimulation outcome by comparing a variety of pain and functional/quality‐of‐life measures before and after management. This report details results after 1 year of stimulation. Summary of Background Data The historically diverse methods, patient selection criteria, and outcome measures reported in the spinal cord stimulation literature have made interpretation and comparison of results difficult. Although short‐term outcomes are generally consistent, long‐term outcomes of spinal cord stimulation, as determined by prospective studies that assess multidimensional aspects of the pain complaint among a relatively homogeneous population, are not well established. Methods Two hundred nineteen patients were entered at six centers throughout the United States. All patients underwent a trial of stimulation before implant of the permanent system. Most were psychologically screened. One hundred eighty‐two patients were implanted with a permanent stimulating system. At the time of this report, complete 1‐year follow‐up data were available on 70 patients, 86% of whom reported pain in the back or lower extremities. Patient evaluation of pain and functional levels was completed before implantation and 3, 6, 12, and 24 months after implantation. Complications, medication usage, and work status also were monitored. Results All pain and quality‐of‐life measures showed statistically significant improvement during the treatment year. These included the average pain visual analogue scale, the McGill Pain Questionnaire, the Oswestry Disability Questionnaire, the Sickness Impact Profile, and the Beck Depression Inventory. Overall success of the therapy was defined as at least 50% pain relief and patient assessment of the procedure as fully or partially beneficial and worthwhile. Using this definition, spinal cord stimulation successfully managed pain in 55% of patients on whom 1‐year follow‐up is available. Complications requiring surgical intervention were reported by 17% (12 of 70) of patients. Medication usage and work status were not changed significantly. Conclusions This prospective, multicenter study confirms that spinal cord stimulation can be an effective therapy for management of chronic low back and extremity pain. Significant improvements in many aspects of the pain condition were measured, and complications were minimal.

Behavioral rating scales for assessing phencyclidine-induced locomotor activity, stereotypes behavior and ataxia in rats

Behavioral rating scales were developed for quantification of phencyclidine (PCP)-induced locomotor activity, stereotyped behavior and ataxia in rats. The dose-response relationship for PCP-induced locomotor activity was found to be an inverted U-shaped function over the first 25 min after injection while over the last 30 min of the experiment the function was highly linear. A linear dose-response relationship was found for ratings of stereotyped behavior and ataxia throughout the 90 min period of observation. The ratings of these two behaviors were found to be closely parallel. The effects of PCP on locomotor activity were found to be greatest during those intervals when stereotyped behavior and ataxia were at moderate levels. Ratings of locomotor activity may be confounded by ataxia when PCP is administered alone or in combination with other drugs.

A Minimally Invasive Technique for Decompression of the Lumbar Spine

Study Design. The technical feasibility of percutaneous microendoscopic bilateral decompression of lumbar stenosis via a unilateral approach was evaluated in a human cadaver model. Objectives. The purpose of this study was to determine the feasibility of using a microendoscopic laminotomy technique to treat spinal stenosis. Summary and Background Data. Minimally invasive surgery is an important means of reducing tissue trauma and patient morbidity. This may prove to be essential in improving pain and in reducing postoperative stress responses and delayed sequelae that can lead to unfortunate complications after otherwise uneventful procedures. To date, minimally invasive lumbar endoscopic techniques have not been used to decompress the lumbar spinal canal. Methods. In each of four cadavers, the laminae of L1 through L4 were subjected to one of four procedures consisting of unilateral microendoscopic laminotomy, bilateral microendoscopic laminotomy, unilateral open laminotomy, and bilateral open laminotomy. Every procedure was performed once at all levels. Computed tomography was performed before and after laminotomy to establish the extent of decompression of the spinal canal, and measurements of the midsagittal, interpedicular, and decompression diameters were taken. Results. The four procedures were successfully performed at every level. Satisfactory decompression of the spinal canal was achieved regardless of the approach used. The exiting nerve roots were well visualized when any one of these techniques was used. Complications, including dural tears and facet complex instability, were independent of the procedure performed. Conclusion. Microendoscopic laminotomy can be used to decompress the spinal canal as effectively as an open laminotomy and may prove to be beneficial in decreasing the complications and morbidity of standard treatments for lumbar stenosis.

Surgical site infection rates after minimally invasive spinal surgery

OBJECT Postoperative surgical site infections (SSIs) have been reported after 2-6% of spinal surgeries in most large series. The incidence of SSI can be < 1% after decompressive procedures and > 10% after instrumented fusions. Anecdotal evidence has suggested that there is a lower rate of SSI when minimally invasive techniques are used. METHODS A retrospective review of prospectively collected databases of consecutive patients who underwent minimally invasive spinal surgery was performed. Minimally invasive spinal surgery was defined as any spinal procedure performed through a tubular retractor system. All surgeries were performed under standard sterile conditions with preoperative antibiotic prophylaxis. The databases were reviewed for any infectious complications. Cases of SSI were identified and reviewed for clinically relevant details. The incidence of postoperative SSIs was then calculated for the entire cohort as well as for subgroups based on the type of procedure performed, and then compared with an analogous series selected from an extensive literature review. RESULTS The authors performed 1338 minimally invasive spinal surgeries in 1274 patients of average age 55.5 years. The primary diagnosis was degenerative in nature in 93% of cases. A single minimally invasive spinal surgery procedure was undertaken in 1213 patients, 2 procedures in 58, and 3 procedures in 3 patients. The region of surgery was lumbar in 85%, cervical in 12%, and thoracic in 3%. Simple decompressive procedures comprised 78%, instrumented arthrodeses 20%, and minimally invasive intradural procedures 2% of the collected cases. Three postoperative SSIs were detected, 2 were superficial and 1 deep. The procedural rate of SSI for simple decompression was 0.10%, and for minimally invasive fusion/fixation was 0.74%. The total SSI rate for the entire group was only 0.22%. CONCLUSIONS Minimally invasive spinal surgery techniques may reduce postoperative wound infections as much as 10-fold compared with other large, modern series of open spinal surgery published in the literature.

Dynamic interspinous process technology.

Study Design. A literature review. Objectives. To evaluate the mechanisms of action and effectiveness of interspinous distraction devices in managing symptomatic lumbar spinal pathology. Summary of Background Data. Fusion operations have traditionally been used to manage many disorders of the lumbar spine related to deformity, pain, or instability. Concern over the long-term effects of fusion on adjacent segments has led to the development of the concept of dynamic stabilization. Methods. A Medline search was performed using the key words “interspinous implants,” “interspinous devices,” and “lumbar dynamic stabilization.” The abstracts of each were reviewed. Relevant articles were reviewed in detail and other appropriate references obtained. In addition, when available, nonpublished manufacturer’s information was reviewed. Results. Articles describing the following implants were included in this review: the Minns Device, the Interspinous “U,” the Diam, the Wallis Implant, and the X STOP. Conclusions. These devices continue to be evaluated in clinical trials. Early results suggest a possible role in the management of degenerative disorders of the lumbar spine.

Microendoscopic Decompressive Laminotomy for the Treatment of Lumbar Stenosis

OBJECTIVE By modifying existing microendoscopic discectomy techniques, we previously developed a novel surgical treatment of lumbar stenosis and validated its ability to achieve a thorough decompression in a cadaveric study. We now describe our clinical experience with this new, minimally invasive microendoscopic decompressive laminotomy (MEDL) technique. METHODS A MEDL was performed in 25 patients with classic features of lumbar stenosis. By use of a fluoroscopically guided percutaneous technique, the working portal was docked on the lamina with minimal soft-tissue injury. With the angle of the endoscope combined with an oblique entry, a bilateral bony and ligamentous decompression was achieved under the midline, thereby preserving the supraspinous–interspinous ligaments and contralateral musculature. A second group of 25 patients treated with open decompression was used for comparison. RESULTS Effective circumferential decompression was achieved in the majority of patients. The results for the MEDL group were as follows: operative time, 109 minutes per single level; blood loss, 68 ml; and postoperative stay, 42 hours. The results for the open-surgery group were as follows: operative time, 88 minutes; blood loss, 193 ml; and postoperative stay, 94 hours. The MEDL group needed significantly less narcotic medication after surgery. Overall, 16% of the MEDL patients reported resolution of their back pain, 68% improved symptomatically, and 16% remained unchanged. The outcome of the open group was very similar. CONCLUSION Compared with an equivalent open technique, MEDL appears to offer a similar short-term clinical outcome with a significant reduction in operative blood loss, postoperative stay, and use of narcotics. This lower surgical stress, decreased tissue trauma, and quicker recovery are particularly important in this elderly population of patients.

Minimally Invasive Cervical Microendoscopic Foraminotomy: An Initial Clinical Experience

OBJECTIVE We have previously reported the feasibility of using the microendoscopic foraminotomy (MEF) technique in a cadaveric study. We now report our initial clinical experience with this novel technique. METHODS From March 1998 to January 2001, we prospectively used the MEF technique in 25 patients with cervical root compression from either foraminal stenosis or disc herniation. The patients’ demographic, clinical presentation, surgical, and outcome data were recorded. Another 26 patients treated via open cervical laminoforaminotomy were used for comparison. RESULTS MEF cases involved less blood loss (138 versus 246 ml per level). MEF patients recovered more rapidly, had a shorter postoperative stay (20 versus 68 hours), and needed fewer narcotics (11 versus 40 equivalents). There were two durotomies after MEF. Overall, our initial experience with the MEF procedure yielded symptomatic improvement for approximately 87 to 92% of patients, depending on which symptom was analyzed. After MEF (mean follow-up, 16 mo; minimum follow-up, 1 year), patients with radiculopathy experienced resolution of their symptoms in 54%, improvement in 38%, and no change in 8% of cases. For open surgery, radiculopathy resolved in 48%, improved in 40%, and remained unchanged in 12%. For neck pain, the MEF results were 40% resolved, 47% improved, and 13% unchanged. Open results for neck pain were 33% resolved, 56% improved, and 11% unchanged. Overall, there was no significant difference in outcomes between the groups. CONCLUSION The MEF technique yielded clinical results equivalent to those of the open surgical group as well as to those described in the literature. MEF patients, however, had less blood loss, shorter hospitalizations, and a much lower postoperative pain medication requirement.

Minimally invasive percutaneous posterior lumbar interbody fusion.

OBJECTIVE The wide exposure required for a standard posterior lumbar interbody fusion (PLIF) can cause unnecessary trauma to the lumbar musculoligamentous complex. By combining existing microendoscopic, percutaneous instrumentation and interbody technologies, a novel, minimally invasive, percutaneous PLIF technique was developed to minimize such iatrogenic tissue injury (MIP-PLIF). METHODS The MIP-PLIF technique was validated in three cadaveric torsos with six motion segments decompressed and fused. Preoperative variables measured from imaging included interpedicular distance, pedicular height and width, interspinous distance, lordosis, intervertebral height, Cobb angle, and foraminal height and volume. Using the METRx and MD spinal access systems (Medtronic Sofamor Danek, Memphis, TN), bilateral laminotomies were performed using a hybrid of microsurgical and microendoscopic techniques. The intervertebral disc spaces were then distracted and prepared with the Tangent (Medtronic Sofamor Danek) interbody instruments. Either a 10 or 12 by 22 mm interbody graft was then placed. Using the Sextant (Medtronic Sofamor Danek) system, percutaneous pedicle screw-rod fixation of the motion segment was completed. We then applied MIP-PLIF in three patients. RESULTS For segments with preoperative intervertebral/foraminal height loss, MIP-PLIF was effective in restoring both heights in all cases. The amount of improvement (9.7 to 38% disc height increase; 7.7 to 29.9% foraminal height increase) varied directly with the size of the graft used and the original degree of disc and foraminal height loss. Segmental lordosis improved by 29% on average. Graft and screw placement was accurate in the cadavers, except for a single Grade 1 screw violation of one pedicle. The average operative time was 3.5 hours per level. In our three clinical cases, the MIP-PLIF procedure required a mean of 5.4 hours, estimated blood loss was 185 ml, and inpatient stay was 2.8 days, with no intravenous narcotic use after 2 days in any of the patients. All screw and graft placements were confirmed. CONCLUSION A complete PLIF procedure can be safely and effectively performed using minimally invasive techniques, thereby potentially reducing the pain and morbidity associated with standard open surgery. Prospective, randomized outcome studies will be required to validate the efficacy of this exciting new surgical technique.

Microendoscopic lumbar discectomy: technical note.

OBJECTIVE The microendoscopic discectomy (MED) technique was initially developed in 1997 to treat herniated lumbar disc disease. Since then, thousands of cases have been successfully performed at more than 500 institutions. This article discusses the technical aspects of this procedure and presents a consecutive case series. METHODS A total of 150 consecutive patients underwent MED. MED is performed by a muscle-splitting approach using a series of tubular dilators with consecutively increasing diameters. A tubular retractor is then inserted over the final dilator, and a specially designed endoscope is placed inside the tubular retractor. The microdiscectomy is performed endoscopically while the surgeon views the procedure on a video monitor. RESULTS Clinical outcomes were determined using a modified MacNab criteria, which revealed that 77% of patients had excellent, 17% had good, 3% had fair, and 3% had poor outcomes. The average hospital stay was 7.7 hours. The average return to work period was 17 days. Complications primarily included dural tears, which occurred in 8 patients (5%) and were seen early on in the patient series. Complication rates diminished as the surgeon’s experience with this technique increased. CONCLUSION MED for lumbar herniated disc disease can be performed safely and effectively, resulting in a shortened hospital stay and faster return to work; however, there is a learning curve to this procedure.