[Show abstract][Hide abstract] ABSTRACT: We report a 6-year retrospective review of screw placement utilizing a percutaneous dynamic reference frame attached to the posterior superior iliac spine performed by a single orthopedic surgeon. We included all lumbar spine procedures utilizing computer-assisted spinal navigation (StealthStation Navigation System, Medtronic Navigation, Louisville, Colo) performed from 2000 to 2005, with 272 of 289 patients (94.1%) having at least a 4-month follow-up with radiographs. Six hundred seventy-two screws were placed. Following surgery, none of these patients had screw misplacements. One patient (0.4%) had a screw backing out of the pedicle. Eighteen patients (6.6%) had their posterior instrumentation removed. Three had repeat operations but did not have their instrumentation removed. No patient with repeat operations had a screw misplaced.
Preview · Article · Aug 2009 · American journal of orthopedics (Belle Mead, N.J.)
[Show abstract][Hide abstract] ABSTRACT: Sacral fractures are a treatment challenge for the orthopaedic surgeon. The relative rarity of sacral fractures limits physician exposure to these injuries and has resulted in questions regarding their optimal treatment. Proper diagnosis and classification also are subjects of considerable debate. Studies of sacral fractures have been mainly retrospective in nature and have involved heterogeneous and small patient populations. The current literature is, therefore, limited.
No preview · Article · Feb 2009 · Instructional course lectures
[Show abstract][Hide abstract] ABSTRACT: Prospective, randomized, multicenter clinical trial.
Kinematic analysis of target level and adjacent motion segments after Bryan artificial cervical disc replacement versus anterior cervical fusion.
Disc arthroplasty has been shown to provide short-term clinical results that are comparable or better than those attained with traditional anterior cervical discectomy and fusion. One purported benefit of arthroplasty is the ability to prevent or delay adjacent level operations.
All patients received either a single-level anterior cervical discectomy and fusion with an anterior cervical plate (Atlantis anterior cervical plate, n=221) or a single-level artificial cervical disc replacement (Bryan cervical disc prosthesis, n=242) at C3 to C7. Flexion, extension, and neutral lateral radiographs were obtained preoperatively, and at regular intervals of 24 months. Cervical vertebral bodies were tracked to calculate the functional spinal unit motion parameters, including flexion/extension range of motion and translation. If visible, the functional spinal unit parameters were obtained at the operative level as well as the level above and below.
Significantly more motion was retained in the disc replacement group than the plated group at the index level. The disc replacement group retained an average of 7.95 degrees at 24 months. The preoperative motion was 6.43 degrees and there was no evidence of degradation of motion over 24 months. In contrast, the average range of motion in the fusion group was 1.11 degrees at 3-month follow-up and gradually decreased to 0.87 degrees at 24 months. The preoperative motion was 8.39 degrees. The Bryan disc did not migrate. At 24-month follow-up, there was no case of subsidence of the Bryan disc. There was no evidence of bridging bone across any of the Bryan implant disc spaces.
The Bryan disc treatment, on average, maintained flexion/extension range of motion without degradation over 24 months. No ectopic bridging ossification was seen in any of the Bryan discs and no subsidence or displacement of the Bryan disc occurred.
No preview · Article · Sep 2008 · Journal of spinal disorders & techniques
[Show abstract][Hide abstract] ABSTRACT: Disc arthroplasty has been shown to provide short-term clinical results that are comparable with those attained with traditional anterior cervical discectomy and fusion. One proposed benefit of arthroplasty is the ability to prevent or delay adjacent level operations by retaining motion at the target level and eliminating abnormal adjacent activity. This paper compares motion parameters for single-level anterior cervical discectomy and fusion and disc replacement patients at the index level and adjacent segments.
Radiographic data from patients enrolled in a prospective, randomized clinical trial were selected for kinematic assessment of cervical motion. All patients received either a single-level fusion with allograft and anterior cervical plate (Atlantis anterior cervical plate, n=13) or a single-level artificial cervical disc (Bryan Cervical Disc prosthesis, n=9) at either C5/C6 or C6/C7. Flexion, extension, and neutral lateral radiographs were obtained preoperatively, immediately postoperatively, and at regular intervals up to 24-month time points. Cervical vertebral bodies were tracked on the digital radiographs using quantitative motion analysis software (QMA, Medical Metrics) to calculate the functional spinal unit motion parameters including range of motion (ROM), translation, and center of rotation. If visible, the functional spinal unit parameters were obtained at the operative level, and also the level above and the level below.
As expected, significantly (P<0.006 at 3, 6, 12, and 24 mo) more flexion/extension motion was retained in the disc replacement group than the plated group at the index level. The disc replacement group retained an average of 6.7 degrees at 24 months. In contrast, the average ROM in the fusion group was 2.0 degrees at the 3-month follow-up and gradually decreased to 0.6 degrees at 24 months. The flexion/extension ROM both above and below the operative level was not statistically different for the disc-replaced and fusion patients, however, mobility increased for both groups over time. The anterior/posterior translation that occurs with flexion/extension motion remained unchanged for the disc replacement group at the level above the target disc preoperatively and postoperatively. In contrast, the translation increased for the level above the fusion. At the 6-month follow-up, the increase in translation was significantly greater for patients that were fused (P<0.02) than for patients that received a disc replacement. This change was not significant at 12 months.
Previous studies have shown the Bryan disc to maintain mobility at the level of the prosthesis. The long-term clinical benefit of maintenance of motion is postulated to be the ability to delay or avoid adjacent level operations. This study reveals that there is no difference in flexion/extension ROM at the level above and below either a fusion or Bryan arthroplasty. There is, however, an increase in anterior/posterior translation at the cephalad adjacent level in patients with arthrodesis while the Bryan arthroplasty retains normal translation for the same amount of flexion/extension at the adjacent level.
The Bryan disc may delay adjacent level degeneration by preserving preoperative kinematics at adjacent levels.
Preview · Article · Feb 2008 · Journal of Spinal Disorders & Techniques
[Show abstract][Hide abstract] ABSTRACT: A retrospective review including patient follow-up on all lumbar decompression procedures by 1 of 2 surgeons.
To evaluate the success of lumbar decompressions performed on an outpatient basis on patients 65 years of age or older.
The efficacy of decompression procedures on the lumbar spine is documented and is often performed on an outpatient basis. Few studies have evaluated these procedures in older adults, and none in a greater population of patients on an outpatient basis.
A total of 1377 lumbar decompression procedures were performed from 1992 to 2001 by 2 surgeons, 263 of these on patients 65 years of age or older. A chart review was done on all procedures. Follow-ups occurred from June 2001 to August 2003 by an unbiased observer not involved in the surgical procedures.
A total of 30 (11.4%) of the 263 procedures were done with a hospital stay: 10 patients of 243 planned inpatient procedures (4.1%) were converted due to a complication. Of the 233 done on an outpatient basis, 4 (1.7%) had a complication. A total of 152 patients (57.8%) completed a questionnaire by phone or mail by an unbiased observer at least 18 months after surgery. A total of 97 of 134 patients (72.4%) said they would repeat the outpatient procedure, and 94 of 136 patients (69.1%) stated that their surgery's outcome was good or better.
For the aged patient, surgical decompression of the lumbar spine can be performed on an outpatient basis safely and successfully.
[Show abstract][Hide abstract] ABSTRACT: Currently, many spine surgeons perform microlumbar discectomies on an outpatient basis. Yet, it is often customary for patients to have a 1-night stay in the hospital. Many studies have shown the efficacy of microlumbar discectomy (MLD) and its preference among surgeons for the treatment of lumbar disc herniation. It has also been shown to be safe, successful, and cost-effective. However, a large comprehensive study of this magnitude, gauging safety, success, and patient satisfaction for these procedures on an outpatient basis has not yet been done. One thousand three hundred seventy-seven MLD procedures have been done from 1992 to 2001 by 1 surgeon. A retrospective chart review was done on all procedures. Patients were then contacted by either telephone or mail to complete an outcome questionnaire. Seven hundred thirteen patients (53.9%) completed the questionnaire. Follow-up questionnaires were not completed due to deaths, incorrect contact information, and refused responses. Out of all MLD procedures, 55 (4.0%) were done with a hospital stay-only 24 of these (1.7%) were originally intended outpatient procedures. Of those that were done on an outpatient basis, 8.6% had a complication, including 6.4% who had a recurrent disc herniation. When asked, 81.6% said they would undergo the procedure again as an outpatient. In 82.1% the surgery's outcome was good, very good, or excellent. MLD is a routine procedure that can be performed on an outpatient basis safely, successfully, and with high patient satisfaction.
No preview · Article · Aug 2006 · Journal of Spinal Disorders & Techniques
[Show abstract][Hide abstract] ABSTRACT: Operative management of a thoracolumbar burst fracture varies according to many factors. Fracture morphology, neurologic status, and surgeon preference play major roles in deciding upon anterior, posterior, or combined approaches. Optimizing neural decompression while providing stable internal fixation over the least number of spinal segments is the goal. Short-segment constructs via a single-stage approach (anterior versus posterior) have become viable options with advances in instrumentation and techniques. This study compares anterior-only fixation utilizing a corpectomy strut graft and a modern thoracolumbar plating system with a posterior-only construct using pedicle screws and load sharing hooks for the treatment of unstable burst fractures. Functional outcome and sagittal plane restoration and maintenance of sagittal plane alignment were evaluated. Fifty-three patients with unstable burst fractures were assessed with 40 undergoing an anterior-only construct and 13 having a short-segment posterior-only construct. The posterior-only group had no hardware failures; however, the loss of sagittal plane correction averaged 8.1 degrees, whereas the anterior-only group averaged only a 1.8-degree increase in sagittal plane kyphosis. Both techniques resulted in statistically significant initial improvement in sagittal alignment; however, the posterior short-segment group lost this statistical significance at follow-up whereas the anterior-only group continued to demonstrate statistically significant improvement in sagittal alignment at follow-up compared to preoperative measurements.
[Show abstract][Hide abstract] ABSTRACT: Posterior lumbar fixation with translaminar facet screws is a minimally invasive technique with good success rates. Long-term follow-ups show reduced reoperation rates, a decrease in pain scores, and few complications compared with pedicle screw fixation devices. The purpose of this study was to compare the reoperation rate of translaminar facet screw fixation with that of pedicle screw fixation in 360 degrees anterior and posterior fusions for incapacitating low back pain due to lumbar disc degeneration unresponsive to at least 6 months of aggressive nonoperative treatment.
One hundred five patients underwent a combined circumferential lumbar fusion with posterior fixation for discogenic pain by one surgeon between August 1993 and February 2003. Seventeen patients were excluded from the study owing to their preoperative etiology for fusion or a prior instrumented posterior fusion. A retrospective chart review was done on all 88 remaining patients. Patients were followed in the office, by phone, or by mail to obtain functional outcome measures. Any subsequent operations by this surgeon or another were recorded. The comparison focused on the rate of reoperation on the region of posterior lumbar fixation.
Sixty-seven patients have had at least a 2-year follow-up. Twenty-four patients had a posterior fusion with pedicle screws, and 43 had translaminar facet screw fixation. Nine patients of the pedicle screw population (37.5%) had a reoperation to remove their instrumentation. Two patients of the translaminar facet screw population (4.7%) had reoperations on their lumbar spine. There was a significant association between posterior instrumentation type and reoperation (P = 0.001).
The success of translaminar facet screws in circumferential fusions is justified.
No preview · Article · May 2006 · Journal of Spinal Disorders & Techniques
[Show abstract][Hide abstract] ABSTRACT: Translaminar facet screws are a minimally invasive technique for posterior lumbar fixation with good success rates. Computer-assisted image navigation using virtual fluoroscopy allows multiple simultaneous screens in various planes to plan and drive spinal instrumentation.
This study evaluates the percutaneous placement of translaminar facet screws with the use of virtual fluoroscopy as an image guidance technique.
A human cadaveric study was performed with a percutaneous reference frame applied to the iliac crest. Ten translaminar facet screws were placed bilaterally at five levels. Anteroposterior and lateral images were used to navigate 4.0-mm screws through a percutaneous portal under virtual fluoroscopy.
An axial computed tomographic scan through the instrumented levels was obtained after the screws were placed. Screws were graded on entry, course through the lamina, and terminus. A grading system was devised to grade the course through the lamina.
All 10 screw-entry points were judged optimal at the spinous process laminar junction. There were five Grade I breeches with less than 1/2 the screw through the lamina, and five Grade 0 screw placements with the screw contained completely within the lamina. The termination point was acceptable in five screws. The screws that began on the right and terminated on the left were all found to have grade II breakouts. No screws placed the spinal canal or exiting nerve root at risk.
Virtual fluoroscopy provides significant assistance in percutaneous placement of translaminar facet screws and results in safe position of entry, lamina course, and terminus.
No preview · Article · Sep 2005 · The Spine Journal
[Show abstract][Hide abstract] ABSTRACT: This retrospective review compares the intraoperative and perioperative complications associated with the placement of threaded devices and nonthreaded devices used in anterior lumbar interbody fusions.
Anterior lumbar interbody fusion is a common procedure performed with either a nonthreaded device, such as a femoral ring, or a threaded device, such as with a cage or a bone dowel.
Many studies have been done detailing the fusion rates and biomechanical properties of both devices. However, few studies have been performed evaluating acute complications between the two device types.
A retrospective chart review was performed of 471 consecutive patients who underwent anterior lumbar interbody fusion: 243 with a nonthreaded interbody device and 228 with a threaded interbody device. Operative notes, anesthesia reports, discharge summaries, and follow-up notes were reviewed from 1992 to June 2002. The patients' demographics, diagnosis, number of levels fused, type of device used, length of hospital stay, and acute complications, either intraoperative or perioperative, were collected and analyzed.
Approximately 4.8% of patients with a threaded type interbody device had an intraoperative complication whereas only 0.4% of patients with a nonthreaded type device had an intraoperative complication. There was a significant association between interbody device type (threaded vs. nonthreaded) and occurrence of an intraoperative complication (P = 0.0024).
Placement of threaded devices, such as cages or bone dowels, was associated with a higher acute complication rate than was the placement of nonthreaded devices during anterior lumbar interbody fusion.
[Show abstract][Hide abstract] ABSTRACT: The optimal treatment of "unstable" thoracolumbar injuries remains controversial. Studies have shown the advantages of direct anterior decompression of thoracolumbar injuries along with supplemental posterior instrumentation as a combined or staged procedure. Others have also shown success in decompression as a single-stage anterior procedure, largely limited to two-column (anterior and middle) injuries. A retrospective review of all available clinical and radiographic data was used to classify unstable three-column thoracolumbar fractures according to the Association for the Study of Internal Fixation (AO) classification system. This was conducted to evaluate the efficacy of stand-alone anterior decompression and reconstruction of unstable three-column thoracolumbar injuries, utilizing current-generation anterior spinal instrumentation.
Between 1992 and 1998, 40 patients underwent anterior decompression and two-segment anteriorly instrumented reconstruction for three-column thoracolumbar fractures. Retrospective review of all available clinical and radiographic data was used to classify these unstable injuries according to the AO classification system, evaluating for neurologic changes, spinal canal compromise, preoperative and postoperative segmental angulation, and arthrodesis rate.
According to the AO classification system, there were 24 (60%) type B1.2, 10 (25%) type B2.3, 5 (12.5%) type C1.3, and 1 (2.5%) type C2.1 three-column injuries. Preoperative canal compromise averaged 68.5% and vertebral height loss averaged 44.5%. There were no cases of neurologic deterioration, and 30 (91%) patients with incomplete neurologic deficits improved by at least one modified Frankel grade. Mean preoperative segmental kyphosis of 22.7 degrees was improved to an early mean of 7.4 degrees (P < 0.0001). At latest follow-up, angulation had increased by an average 2.1 degrees but maintained significant improvement from preoperative measurements (P < 0.0001). There was one early construct failure due to technical error. Thirty-seven of the remaining patients (95%) went on to apparently stable arthrodesis.
Current types of anterior spinal instrumentation and reconstruction techniques can allow some types of unstable three-column thoracolumbar injuries to be treated in an anterior stand-alone fashion. This allows direct anterior decompression of neural elements, improvement in segmental angulation, and acceptable rates of arthrodesis without the need for supplemental posterior instrumentation.
No preview · Article · Feb 2005 · Journal of Spinal Disorders & Techniques
[Show abstract][Hide abstract] ABSTRACT: significantly longer than that used by both Boucher and King due to an entry point at the base of the contralateral spinous process. This improves the technique by increasing the ef- fective working length of the screw on both sides of the facet joint resulting in increased strength of the fixation. This review focuses on the advantages of translaminar facet screws as established in both the literature and in our experience. Translaminar facet instrumentation involves minimally invasive techniques without significant soft tissue dissection. Improvements over pedicle screw fixation have been shown in biomechanical stability and stiffness, com- plication rates, reoperation rates, operative time, blood loss, and patient perceived outcomes. Additionally, current intra- operative surgical image navigation techniques are rapidly improving which have increased the accuracy and decreased the operative time in placement of these screws.