Physical capability outcomes after total disc replacement with ProDisc-L.

BACKGROUND: Lumbar disc arthroplasty (total disc replacement [TDR]) outcomes have been evaluated using subjective, patient-reported measures of pain, health, and functional impairment. As a condition of TDR coverage, our institution's health plan required that objective physical performance data be collected. Thus our study was designed to explore (1) the feasibility of using preoperative and 1-year postoperative performance on functional capacity tasks as an outcome metric for TDR with ProDisc-L (PD-L) (Synthes Spine, West Chester, Pennsylvania), (2) the magnitude and significance of changes in preoperative and postoperative performance, and (3) whether changes noted in performance are reflected in the subjective measures. METHODS: Seven adapted WorkWell tasks (physical capability assessment tool [PCAT]) (WorkWell Systems, Duluth, Minnesota) were performed preoperatively and 1 year postoperatively by 18 patients who received either single-level or 2-level PD-L implants. Demographic and medical data were reviewed. RESULTS: The PCAT was implemented easily, and the tasks took approximately 30 minutes to complete. Percent improvement and preoperative and postoperative physical capability outcomes for each PCAT task are as follows: squat, 79% (10.7 ± 7.1 repetitions vs 19.2 ± 2.0 repetitions, P < .001); forward bend, 121% (110.2 ± 68.8 seconds vs 243.6 ± 77.2 seconds, P < .001); kneel, 92% (283.2 ± 173.2 seconds vs 544.7 ± 109.3 seconds, P < .001); floor-to-waist lift, 128% (16.1 ± 9.9 lb vs 36.7 ± 20.3 lb, P < .001); horizontal carry, 119% (19.7 ± 8.6 lb vs 43.2 ± 18.3 lb, P < .001); push, 32% (67.7 ± 19.2 lb vs 89.4 ± 24.4 lb, P < .001); and pull, 40% (57.6 ± 17.1 lb vs 80.9 ± 26.4 lb, P < .001). Visual analog scale scores for pain (5.1 ± 1.7 vs 1.4 ± 1.6, P < .001), Oswestry Disability Index scores (49.0% ± 13.2% vs 15.2% ± 14.3%, P < .001), and amount of narcotic use (26.1 ± 43.8 mg of morphine equivalent vs 1.9 ± 7.3 mg of morphine equivalent, P = .031) also improved. In single-level cases, comparison of L4-5 versus L5-S1 showed significant differences only with the forward bend task (P = .002). CONCLUSIONS/CLINICAL RELEVANCE: The physical capability outcome may be a feasible outcome metric. PD-L implantation may result in substantial improvements in physical performance. Similar benefits shown in a larger series over a longer timeframe could have important implications for the long-term health, productivity, and cost of health care for this patient population.

Prevention of vertebral body-splitting fractures after multilevel ProDisc-L implantation.

BACKGROUND: Prior studies of multilevel ProDisc-L (PD-L) implants (Synthes Spine, Inc., West Chester, Pennsylvania) using the standard US technique have used conventional radiography postoperatively. We found vertebral body-splitting fractures (VB-SFs) in interposed vertebral bodies after 5 sequential multilevel PD-L device implantations using the standard US technique. These were identified with postoperative computed tomography (CT) but were not visible on plain radiographs. In an additional patient, we found that a stress-relieving, pilot holes-only technique did not prevent VB-SFs. The 5 patients operated on with the standard technique composed the background series against which we compared the incidence of VB-SFs in patients operated on with a modification of the standard US technique-a combination of stress-relieving pilot holes, removal of cortex in the chisel path, and a fenestrated chisel (PH/CR/FC)-intended to reduce the incidence of VB-SFs in multilevel PD-L constructs. METHODS: Patients receiving multilevel PD-L implants at 2 sites-1 in the United States and the other in Germany-were operated on with the PH/CR/FC technique and their postoperative CT scans evaluated for the presence of VB-SFs. The frequency of VB-SFs in these patients was compared with that of the 5 patients from the background series who were operated on by the standard US technique. The groups' mean sex, age, body mass index, and vertebral body height, as well as average spinal T score, were also compared. RESULTS: No fractures were found in 13 interposed vertebral bodies in 11 patients operated on with the PH/CR/FC technique, as compared with 4 VB-SFs and 1 anterior keel cut-to-anterior keel cut fracture in 5 interposed vertebral bodies in 5 patients operated on with the US technique (P ≤ .001). Although the sample sizes were small, this difference in fracture rate was not associated with sex, age, body mass index, or average spinal T score. At up to 13 months of follow-up of patients in the background series, we found that VB-SFs tend not to bridge with bone, instead forming sclerotic margins. CONCLUSIONS: The PH/CR/FC technique studied reduced the incidence of VB-SF in multilevel PD-L implants. Because previously published multilevel studies did not use postoperative CT scans and because VB-SFs are not visible on conventional radiography, the incidence of VB-SFs in multilevel PD-L applications may be higher than previously reported. Our findings may contribute to prevention of complications in total disc replacement.

A new paradigm for staging pedicle screw-based spinal procedures: rationale, feasibility, safety, and efficacy.

OBJECT: The aims of this study were to present the rationale for and the evolution of a staged, two-procedure paradigm for spinal surgery requiring pedicle screw instrumentation, and to evaluate the feasibility, safety, and efficacy of the technique. METHODS: The rationale for the new algorithm is presented for consideration in the form of unproven hypotheses subject to verification by subsequent studies. The first stage of the two-staged algorithm, performed in an interventional radiology (IR) setting, involves percutaneous placement of either headless pedicle screws or K-wire fragment placeholders of the trajectory for pedicle screws. The second stage, performed days or weeks later, involves open surgical completion of instrumentation placement and other surgical objectives. The techniques for IR percutaneous K-wire fragment and percutaneous screw placement evolved over the duration of the study. Instrumentation was placed in 126 pedicles in 25 patients. Efficacy was equated to the accuracy of screw placement, which was evaluated using computed tomography (CT). Algorithms incorporating correction for metal artifact were developed to determine deviation of the screws and K-wire fragments from proper position. Over 1500 measurements were made to evaluate K-wire fragment and screw position in the 116 instrumented pedicles for which CT data were available. RESULTS: Accuracy of placement (relative to both cortical and pedicle breaches or to only pedicle breaches) was 98 to 100% for K-wire fragments, 96 to 98% for screws following K-wire fragments, and 100% for percutaneous screws. The only adverse consequence of pedicle screw placement by this method was one infection that occurred 8 months postoperatively. CONCLUSIONS: The staged, two-procedure paradigm for pedicle screw placement proved, within the limits of this study, to be feasible, safe, and effective; therefore, the unproven rationale behind the new paradigm merits further evaluation in a larger cohort of patients with randomized, matched controls.

An institutional approach to maintenance of excellent outcomes for carotid endarterectomy in a setting with moderate-to-low procedure volume.

BACKGROUND: Institutions and surgeons with high procedure volumes have been reported to have lower morbidity and mortality rates for patients undergoing carotid endarterectomy. Demonstrating comparable results is essential for centers with moderate or low volume. If comparable results cannot be demonstrated, a low- to moderate-volume center should not perform the procedure. STUDY DESIGN: A prospective study of a program to achieve and sustain excellent outcomes after carotid endarterectomy was conducted at a single institution with low-to-moderate volumes. Results of this effort from January 1997 through December 2005 are reported. Key features of our approach include institutional control over which and how many surgeons can perform carotid endarterectomy. Surgeons must be experienced carotid surgeons and consistently perform more than 12 procedures annually and be continuously monitored. Surgical outcomes were independently audited through a mandated institutional carotid endarterectomy data registry. Surgeons with poor outcomes are barred from doing carotid endarterectomies; and annually updated outcomes data are posted on the Internet. RESULTS: This approach was used for 555 carotid endarterectomies in 503 patients. Our outcomes-with total death and disabling stroke rate of 1.6%-compare favorably with, and are not statistically different from, published benchmarks, despite volumes at our institution ranging from 44 to 81 patients annually and the participation of 8 surgeons during the study period. CONCLUSIONS: Surgeons should perform carotid endarterectomies only if excellent outcomes can be demonstrated. We conclude that by using an approach like ours, even institutions with moderate-to-low carotid endarterectomy volumes can achieve excellent outcomes. We propose that all institutions should assume responsibility for ensuring excellent carotid endarterectomy outcomes using a comprehensive outcomes-based approach with independent auditing similar to that presented here.

Effect of approach side during anterior cervical discectomy and fusion on the incidence of recurrent laryngeal nerve injury.

OBJECT: This retrospective study was designed to determine whether side of approach during instrumented, one- or two-level primary anterior cervical discectomy and fusion (ACDF) affects the incidence of recurrent laryngeal nerve (RLN) injury diagnosed by observation of the vocal cords (OVC). METHODS: Records of all patients who underwent one- or two-level instrumented primary ACDF (418 patients) between January 1995 and February 2004 were reviewed. Data collected from these charts included surgeon, patient demographics, preoperative diagnosis, side of exposure, number of vertebral levels fused, and presence of RLN injury diagnosed by OVC after referral for persistent dysphonia. Time from surgery to OVC for patients with right-sided exposures was not statistically different from that for patients with left-sided exposures. Of 418 patients, 278 (66.5%) had right-sided exposures and 140 (33.5%) had left-sided exposures. Eight RLN injuries (1.9%) were noted-five in patients with right-sided exposures (1.8%) and three in patients with left-sided exposures (2.1%). The difference between right- and left-sided injury rates was shown to be nonsignificant using Fisher exact tests. CONCLUSIONS: Results indicate that, given the study's sample size, side of approach during instrumented, one- or two-level primary ACDF has no significant effect on RLN injury incidence in patients with persistent dysphonia referred for OVC. The definitive answer regarding the true incidence of RLN injury relative to approach side awaits a prospective study with preoperative, immediate postoperative, and periodic OVC in a large, homogeneous population with sufficient numbers of patients with right- and left-sided approaches.