Cost-effectiveness and Safety of Interspinous Process Decompression (Superion).

OBJECTIVE: There are several treatment options for patients suffering from lumbar spinal stenosis, including surgical and conservative care. Interspinous spacer decompression using the Superion device offers a less invasive procedure for patients who fail conservative treatment before traditional decompression surgery. This review assesses the current cost-effectiveness, safety, and performance of lumbar spinal stenosis treatment modalities compared with the Superion interspinous spacer procedure. METHODS: EMBASE and PubMed were searched to find studies reporting on the cost-effectiveness, safety, and performance of conservative treatment, including medicinal treatments, epidural injections, physical therapy, and alternative methods, as well as surgical treatment, including laminectomy, laminectomy with fusion, and interspinous spacer decompression. Results were supplemented with manual searches. RESULTS: Despite substantial costs, persistent conservative treatment (>12 weeks) of lumbar spinal stenosis showed only minimal improvement in pain and functionality. When conservative treatment fails, surgery is more effective than continuing conservative treatment. Lumbar laminectomy with fusion has considerably greater cost than laminectomy alone, as the length of hospital stay increases, the costs for implants are substantial, and complications increase. Although laminectomy and the Superion have comparable outcomes, the Superion implant is positioned percutaneously. This approach may minimize the direct and indirect costs of outpatient rehabilitation and absenteeism, respectively. CONCLUSIONS: Superion interspinous lumbar decompression is a minimally invasive procedure for patients with lumbar spinal stenosis who have failed conservative treatment. Compared with extending conservative treatment or traditional spinal surgery, interspinous lumbar decompression reduces the direct and indirect costs associated with lumbar spinal stenosis.

Interspinous Process Decompression With The Superion® Spacer For Lumbar Spinal Stenosis: Real-World Experience From A Device Registry.

BACKGROUND: Interspinous process decompression (IPD) with stand-alone spacers has demonstrated excellent long-term clinical benefit for patients with lumbar spinal stenosis (LSS). METHODS: IPD used the Superion® Indirect Decompression System (Vertiflex, Carlsbad, CA, USA). Perioperative and clinical data were captured via a registry for patients treated with IPD for LSS with intermittent neurogenic claudication. Three-hundred sixteen physicians at 86 clinical sites in the US participated. Patient data were captured from in-person interviews and a phone survey. Outcomes included intraoperative blood loss, procedural time, leg and back pain severity (100 mm VAS), patient satisfaction and treatment approval at 3 weeks, 6 and 12 months. RESULTS: The mean age of registry patients was 73.0 ± 9.1 years of which 54% were female. Mean leg pain severity decreased from 76.6 ± 22.4 mm preoperatively to 30.4 ± 34.6 mm at 12 months, reflecting an overall 60% improvement. Corresponding responder rates were 64% (484 of 751), 72% (1,097 of 1,523) and 75% (317 of 423) at 3 weeks, 6 and 12 months, respectively. Back pain severity improved from 76.8 ± 22.2 mm preoperatively to 39.9 ± 32.3 mm at 12 months (48% improvement); 12-month responder rate of 67% (297 of 441). For patient satisfaction at 3 weeks, 6 and 12 months, 89%, 80%, and 80% were satisfied or somewhat satisfied with their treatment and 90%, 75%, and 75% would definitely or probably undergo the same treatment again. In the phone survey, the rate of revision was 3.6% (51 of 1,426). CONCLUSION: These registry findings support the clinical adoption of minimally invasive IPD in patients with neurogenic claudication associated with LSS.

Spinal Cord Stimulation (SCS) with Anatomically Guided (3D) Neural Targeting Shows Superior Chronic Axial Low Back Pain Relief Compared to Traditional SCS-LUMINA Study.

BACKGROUND: The aim of this study was to determine whether spinal cord stimulation (SCS) using 3D neural targeting provided sustained overall and low back pain relief in a broad routine clinical practice population. STUDY DESIGN AND METHODS: This was a multicenter, open-label observational study with an observational arm and retrospective analysis of a matched cohort. After IPG implantation, programming was done using a patient-specific, model-based algorithm to adjust for lead position (3D neural targeting) or previous generation software (traditional). Demographics, medical histories, SCS parameters, pain locations, pain intensities, disabilities, and safety data were collected for all patients. RESULTS: A total of 213 patients using 3D neural targeting were included, with a trial-to-implant ratio of 86%. Patients used seven different lead configurations, with 62% receiving 24 to 32 contacts, and a broad range of stimulation parameters utilizing a mean of 14.3 (±6.1) contacts. At 24 months postimplant, pain intensity decreased significantly from baseline (ΔNRS = 4.2, N = 169, P < 0.0001) and even more in in the severe pain subgroup (ΔNRS = 5.3, N = 91, P < 0.0001). Axial low back pain also decreased significantly from baseline to 24 months (ΔNRS = 4.1, N = 70, P < 0.0001, on the overall cohort and ΔNRS = 5.6, N = 38, on the severe subgroup). Matched cohort comparison with 213 patients treated with traditional SCS at the same centers showed overall pain responder rates of 51% (traditional SCS) and 74% (neural targeting SCS) and axial low back pain responder rates of 41% and 71% in the traditional SCS and neural targeting SCS cohorts, respectively. Lastly, complications occurred in a total of 33 of the 213 patients, with a 1.6% lead replacement rate and a 1.6% explant rate. CONCLUSIONS: Our results suggest that 3D neural targeting SCS and its associated hardware flexibility provide effective treatment for both chronic leg and chronic axial low back pain that is significantly superior to traditional SCS.

Percutaneous Rupture of a Symptomatic Facet Joint Synovial Cyst Using 2-Needle Distention.

OBJECTIVE: This case report calls attention to an alternative approach for management of a symptomatic facet joint synovial cyst. We describe a patient with a symptomatic facet joint synovial cyst who failed an attempted percutaneous rupture using a single-needle technique. This patient was subsequently successfully managed with percutaneous rupture using a 2-needle technique. CASE REPORT: A 60-year-old woman presented with low back pain, right lower extremity pain, and paresthesias. Magnetic resonance imaging revealed a right L5-S1 facet joint cyst, which compressed the right L5 nerve root. Before presentation, the patient failed an attempted single-needle percutaneous rupture. The decision was made to proceed with percutaneous rupture using a 2-needle technique. A 22-gauge needle was inserted into the right L5-S1 facet joint, and a Tuohy needle was inserted directly into the cyst through an interlaminar approach. A solution of methylprednisolone and hyaluronidase was simultaneously injected through both needles, and the cyst was continuously distended until rupture was achieved. Rupture was confirmed by injecting contrast into the facet joint and visualizing a normal epidurogram. The patient reported significant pain relief immediately after the procedure. At 4-month follow-up, the patient reported continued pain relief and denied any radicular symptoms. CONCLUSIONS: Percutaneous rupture of a symptomatic facet joint synovial cyst using a single-needle technique has been validated as an efficacious form of management. In a select group of patients who fail single-needle percutaneous rupture, a 2-needle approach for percutaneous facet cyst rupture may be considered as an option for management.

Peripheral nerve field stimulation for the management of localized chronic intractable back pain: results from a randomized controlled study.

OBJECTIVES: Improved device technology has caused a renewed interest in peripheral nerve field stimulation (PNfS). This study sought to obtain preliminary estimates of the safety and efficacy of PNfS in patients with localized chronic intractable pain of the back. MATERIALS AND METHODS: This Institutional Review Board-approved, prospective, randomized, controlled, crossover study consisted of two phases. During phase I, patients rotated through four stimulation groups (minimal, subthreshold, low frequency, and standard stimulation). If a 50% reduction in pain was achieved during any of the three active stimulation groups (responder), the patient proceeded to phase II, which began with implant of the permanent system and lasted 52 weeks. The primary endpoint was a reduction in pain, assessed by the visual analog scale (VAS). Analysis of variance, including the effects of patient, treatment, and study period, was used for phase I results. Phase II results were analyzed by paired t-tests. RESULTS: A total of 44 patients were enrolled at five sites. Of these patients, 32 were implanted with a trial system and 30 completed phase I. During phase I, there were significant differences in mean VAS scores between minimal stimulation and subthreshold stimulation (p = 0.003), low frequency stimulation (p < 0.001), and standard stimulation (p < 0.001). Twenty-four patients were classified as responders to the therapy, and 23 patients received permanent system placement. Significant differences in VAS scores were observed between baseline and all follow-up visits during phase II (p < 0.001) CONCLUSIONS: The results provide evidence to support safety and effectiveness of PNfS as an aid in the management of chronic, localized back pain.

Peripheral nerve stimulation for the treatment of truncal pain.

Neuromodulation practitioners increasingly recognize the potential for peripheral nerve field stimulation (PNfS) to treat pain originating from the trunk. Conditions resulting in truncal pain that may respond to PNfS include cervical and lumbar postlaminectomy syndrome, inguinal neurapraxia, post-herpetic neuralgia, and post-thoracotomy pain. The focus of this chapter is to review the mechanism of action in PNfS, patient selection factors, programming strategies, and technical considerations.

Stimulation of the peripheral nervous system for the painful extremity.

Peripheral nerve stimulation and, recently, peripheral nerve field stimulation are excellent options for the control of extremity pain in instances where conventional methods have failed and surgical treatment is ruled inappropriate. New techniques, ultrasound guidance, smaller generators, and task-specific neuromodulatory hardware and leads result in increasingly safe, stable and efficacious treatment of pain in the extremities. Peripheral nerve stimulation has shown to be an increasingly viable option for many painful conditions with neuropathic and possibly nociceptive origins. This chapter focuses on the historical use of neuromodulation in the extremities, technical tasks associated with implant, selection of candidates, and potential pitfalls of and solutions for implanting devices around the peripheral nervous system for extremity pain.

Cervical nerve root stimulation. Part I: technical aspects and normal data.

OBJECTIVE: Cervical nerve root stimulation (CRS) is a technique of assessing the proximal segments of motor axons destined to upper extremity muscles. Few studies report normal values. The objective was to determine CMAP onset-latencies and CMAP amplitude, area, and duration changes in healthy controls for the abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps, and riceps muscles. In addition, to determine the tolerability of CRS, as measured by the visual analog scale (VAS). METHODS: We studied 21 healthy volunteers prospectively with CRS using four target muscles (APB, ADM, biceps, and triceps) bilaterally. Collision studies were used in all APB recordings. VAS was obtained in all subjects. RESULTS: Mean CMAP onset-latencies were: APB 14 +/- 1.5 ms; ADM 14.2 +/- 1.5 ms; biceps 5.4 +/- 0.6 ms; triceps 5.4 +/- 1.0 ms. Onset-latency significantly correlated with height for all nerves. The mean change in CMAP amplitude and area (%) between most distal stimulation and CRS was: APB reduction of 15.1 +/- 11.6 and 4.9 +/- 3.6%; ADM reduction of 21.1 +/- 10.7 and 17.2 +/- 8.8; biceps reduction of 10 +/- 11.5 and reduction of 8.7 +/- 6.8; triceps increase of 3.3 +/- 5.2 and 11.0 +/- 9.9% respectively. Mean CMAP duration change between most distal stimulation and CRS was: APB, increase of 20.4 +/- 7.4%; ADM, increase of 14.4 +/- 8.5%; biceps, increase of 13.9 +/- 10.8%; triceps, increase of 7.7 +/- 6.7%. The mean VAS score was 3.8 +/- 1.2, and all subjects completed the study. CONCLUSIONS: The present study establishes normative data and indicates that CRS is a well-tolerated technique. SIGNIFICANCE: The normal values may be used as reference data for the needle CRS technique in the assessment of proximal conduction abnormalities.

Neurophysiologic findings in early acute inflammatory demyelinating polyradiculoneuropathy.

BACKGROUND: Patients with early acute inflammatory demyelinating polyradiculoneuropathy (AIDP) may not meet the current neurophysiologic criteria. OBJECTIVE: To document neurophysiologic findings in early AIDP. METHODS: Clinical and neurophysiologic data from 38 AIDP patients, assessed within 10 days of symptom onset were reviewed. RESULTS: In addition to absent H reflexes and abnormal F-wave responses in the acute stage of AIDP, abnormalities of blink reflexes, upper limb sensory responses abnormalities with spared sural responses, presence of distal CMAP dispersion, and A-waves were frequently observed. Established demyelinating neurophysiologic parameters were infrequently seen. CONCLUSIONS: Abnormalities of H reflexes and F responses were most frequently noted in early AIDP. Additionally, distal temporal dispersion, prolonged or absent blink reflexes, and A-waves were often present in the acute stage of AIDP when classic diagnostic criteria of AIDP were not satisfied. SIGNIFICANCE: Neurophysiologic studies in early AIDP frequently reveal abnormalities that are not specific of primary demyelinating neuropathy.

Effects of treadmill walking speed on lateral gastrocnemius muscle firing.

OBJECTIVE: To study the electromyographic profile--including ON, OFF, and peak timing locations--of the lateral gastrocnemius muscle over a wide range of walking speeds (0.5-2.1 m/sec) in healthy young adults. DESIGN: We studied gastrocnemius muscle-firing patterns using an electromyographic surface electrode in 15 healthy subjects ambulating on a treadmill at their normal walking speed and at three paced walking speeds (0.5, 1.8, and 2.1 m/sec). Initial heel contact was determined from a force-sensitive switch secured to the skin over the calcaneous. RESULTS: For all speeds, the gastrocnemius firing pattern was characterized by a main peak, occurring 40-45% into the gait cycle, that increased in amplitude with walking speed. Speeds of > or =1.3 m/sec produced a common electromyographic timing profile, when the profile is expressed relative to the stride duration. However, at 0.5 m/sec (a speed typical of individuals with upper-motor neuron lesions), the onset of gastrocnemius firing was significantly delayed by 3-6% of the gait cycle and was prolonged by 8-11% of the gait cycle. CONCLUSION: Many patients with upper motor neuron lesions (e.g., stroke and traumatic brain injury) walk at speeds much slower than those commonly described in the literature for normal gait. At the slow walking speed of 0.5 m/sec, we have measured noticeable changes in the electromyographic timing profile of the gastrocnemius muscle. Given the importance of appropriate plantar flexor firing patterns to maximize walking efficiency, understanding the speed-related changes in gastrocnemius firing patterns may be essential to gait restoration.

PoWER Program: People with Disabilities Educating Residents.

An educational program was developed incorporating people with disabilities (PWDs) as "consumer-trainers" who educate physical medicine and rehabilitation residents about challenges in everyday living and their solutions to these. During the residency postgraduate years 2 and 4, pairs of residents visited trainers in their homes and at their jobs to learn about their lifestyles and adaptations. Residents' described the experience as "excellent, outstanding, invaluable" in more than half of the evaluations. PWDs can educate physical medicine and rehabilitation residents about living with disabilities. This new residency educational strategy encourages residents to value the perspective of PWDs.

Growth factors and stem cells as treatments for stroke recovery.

Both polypeptide growth factors and stem cell populations from bone marrow and umbilical cord blood hold promise as treatments to enhance neurologic recovery after stroke. Growth factors may exert their effects through stimulation of neural sprouting and enhancement of endogenous progenitor cell proliferation, migration, and differentiation in brain. Exogenous stem cells may exert their effects by acting as miniature "factories" for trophic substances in the poststroke brain. The combination of growth factors and stem cells may be more effective than either treatment alone. Stroke recovery represents a new and relatively untested target for stroke therapeutics. Whereas acute stroke treatments focus on agents that dissolve blot clots (thrombolytics) and antagonize cell death (neuroprotective agents), stroke recovery treatments are likely to enhance structural and functional reorganization (plasticity) of the damaged brain. Successful clinical trials of stroke recovery-promoting agents are likely to be quite different from trials testing acute stroke therapies. In particular, the time window of effective treatment to enhance stroke recovery is likely to be far longer than that for acute stroke treatments, perhaps days or weeks rather than minutes or hours after stroke. This longer time window means that time is available for careful screening and testing of potential subjects for stroke recovery trials, both in terms of size and location of cerebral infarcts and in type and severity of neurologic deficits. Detailed baseline information can be obtained for each patient against which eventual clinical outcome can be compared. Finally, separate and detailed outcome measures can be obtained in both the sensorimotor and cognitive neurologic spheres, because it is possible that these two kinds of function may recover differently or be differentially responsive to recovery-promoting treatments. Stroke recovery represents an important and underexplored opportunity for the development of new stroke treatments.

Influence of poststroke urinary incontinence on disability: the nursing home setting.

OBJECTIVE: To characterize the association of poststroke urinary incontinence with disability progression in nursing home residents. DESIGN: In this prospective cohort study, the Minimum Data Set from the State of New York between 1994 and 1997 was utilized. From a pool of over 240,000 potential subjects, 500 met inclusion/exclusion criteria. Previously continent, first-time stroke survivors were classified as being continent or incontinent immediately after their stroke and were followed for changes in activities of daily living status (disability) at quarterly intervals for a 1 yr. In addition, a post hoc analysis was performed examining changes in activities of daily living status from the prestroke condition and exploring the relationship between poststroke impairments in continence and limitations in mobility. RESULTS: An almost 2-fold difference in level of disability was noted poststroke among those who were incontinent those who were continent (P < 0.001). This difference in disability level remained unchanged for 1 yr. Through the post hoc analysis, it was determined that, although the onset of stroke produced significant elevations in disability for both continent and incontinent stroke survivors (P < 0.001), the presence of an impairment in urinary continence was associated with a significantly greater increase (94% 13%) in disability (P < 0.001). In addition, incontinence occurred more frequently among those who had a loss in mobility function. CONCLUSION: Incontinence is a clinical factor after stroke that is associated with greater disability among nursing home residents. These findings have clinical implications for physiatrists and nursing home clinicians and provide a context in which future disability research can be conducted.

Motor function improvement following intrathecal baclofen pump placement in a patient with locked-in syndrome.

We describe a patient with locked-in syndrome who had minimal volitional motor function and severe spasticity in all four extremities. The patient showed a significant improvement in volitional motor function following intrathecal baclofen pump therapy to control spasticity. This case study suggests that intrathecal baclofen pump therapy might improve motor function in select patients with locked-in syndrome.