Three-dimensional lumbar spine vertebral motion during running using indwelling bone pins.

STUDY DESIGN: Eight healthy volunteers participated in this observational study. OBJECTIVE: Quantify 3-dimensional motions of the lumbar vertebrae during running via direct in vivo measurement and compare these motions to walking data from the same technique and running data from a skin-mounted technique. SUMMARY OF BACKGROUND DATA: Lumbar spine motions in running are only reported in 1 series of articles using a skin-mounted technique subject to overestimation and only instrumented a single vertebra. METHODS: Reflective marker triads were attached to Kirschner wires inserted into the spinous processes of L1-S1. Anatomic registration between each vertebra and attached triad was achieved using spinal computed tomographic scans. Skin-mounted trunk markers were used to assess thoracic motions. Subjects ran several times in a calibrated volume at self-selected speed while 3-dimensional motion data were collected. RESULTS: Lumbar spine flexion and pelvic rotation patterns in running were reversed compared with walking. Increased lumbar spine motions during running occurred at the most inferior segments. Thoracic spine, lumbar spine and pelvis exhibited significantly greater range of sagittal plane motion with running. The pelvis had significantly greater range of frontal plane motion, and the thoracic spine had significantly greater range of transverse plane motion with running. Skin-mounted studies reported as much as 4 times the motion range determined by the indwelling bone pin techniques, indicating that the skin motion relative to the underlying bone during running was greater than the motion of the underlying vertebrae. CONCLUSION: The lumbar spine acts as a distinct functional segment in the spine during running, chiefly contributing lateral flexion to balance the relative motions between the trunk and pelvis. The lumbar spine is also shown to oppose thoracic spine sagittal flexion. While the lumbar spine chiefly contributes to frontal plane motion, the thoracic spine contributes the majority of the transverse plane motion. LEVEL OF EVIDENCE: N/A.

Assessment of three-dimensional lumbar spine vertebral motion during gait with use of indwelling bone pins.

BACKGROUND: This study quantifies the three-dimensional motion of lumbar vertebrae during gait via direct in vivo measurement with the use of indwelling bone pins with retroreflective markers and motion capture. Two previous studies in which bone pins were used were limited to instrumentation of two vertebrae, and neither evaluated motions during gait. While several imaging-based studies of spinal motion have been reported, the restrictions in measurement volume that are inherent to imaging modalities are not conducive to gait applications. METHODS: Eight healthy volunteers with a mean age of 25.1 years were screened to rule out pathology. Then, after local anesthesia was administered, two 1.6-mm Kirschner wires were inserted into the L1, L2, L3, L4, L5, and S1 spinous processes. The wires were clamped together, and reflective marker triads were attached to the end of each wire couple. Subjects underwent spinal computed tomography to anatomically register each vertebra to the attached triad. Subjects then walked several times in a calibrated measurement field at a self-selected speed while motion data were collected. RESULTS: Less than 4° of lumbar intersegmental motion was found in all planes. Motions were highly consistent between subjects, resulting in small group standard deviations. The largest motions were in the coronal plane, and the middle lumbar segments exhibited greater motions than the segments cephalad and caudad to them. Intersegmental lumbar flexion and axial rotation motions were both extremely small at all levels. CONCLUSIONS: The lumbar spine chiefly acts to contribute abduction during stance and adduction during swing to balance the relative motions between the trunk and pelvis. The lumbar spine acts in concert with the thoracic spine. While the lumbar spine chiefly contributes coronal plane motion, the thoracic spine contributes the majority of the transverse plane motion. Both contribute flexion motion in an offset phase pattern. CLINICAL RELEVANCE: This is a valid model for measuring the three-dimensional motion of the spine. Normative data were obtained to better understand the effects of spine disorders on vertebral motion over the gait cycle.

Pyoderma gangrenosum following patellar tendon repair: a case report and review of the literature.

Postoperative pyoderma gangrenosum (PG) is an unusual and devastating complication following surgical procedures. This frequently misdiagnosed entity can progress rapidly if not identified and treated appropriately. A heightened awareness for the diagnosis of PG, coupled with a multidisciplinary approach to the disease, is essential to proper management of this entity. We report on a patient who developed postoperative PG following open repair of a patellar tendon rupture. The follow-up period was 2 years, and a review of the current literature is presented. The diagnosis of PG was confirmed by tissue biopsy, and the condition was treated with high-dose prednisone and dapsone, with complete resolution of symptoms. PG should be part of the differential diagnosis when evaluating patients with postoperative wound complications. Awareness of PG is the key to diagnosis and treatment of this potentially devastating complication.

Comparison of neurotization versus nerve repair in an animal model of chronically denervated muscle.

PURPOSE: Reinnervation of chronically denervated muscle is clinically unpredictable and poorly understood. Current operative strategies include either direct nerve repair, nerve grafting, nerve transfer, or neurotization. The goal of this study is to compare muscle recovery using microneural repair versus neurotization in a rat model of chronic denervation. METHODS: Fifty-eight Sprague-Dawley rats had surgical denervation of the tibialis anterior muscle by transecting the common peroneal nerve. After 0, 8, 12, or 22 weeks of denervation, animals were assigned to either a direct repair or a neurotization cohort. An additional 7 animals were used for a sham cohort, and 7 of the 58 were used as controls. After a 12-week recovery period, animals had contractile strength and EMG testing of the tibialis anterior muscle. Peak force and characteristics were compared to the unoperated, contralateral limb. Tibialis anterior muscles were then harvested for mass and histologic evaluation. RESULTS: Sixty-two animals completed testing. Denervated controls demonstrated a significant decrease in muscle mass, contractile strength, and peak motor nerve conduction amplitude compared to sham animals. In all groups, chronicity of denervation adversely affected functional recovery. On average, repair animals performed better than neurotization animals with respect to muscle mass, contractile strength, and peak motor amplitude. Differences in contractile force, however, were significant only at the 0 week denervation group (94% +/- 30 vs 50% +/- 20, repair vs neurotization). Neurotized muscles processed for histologic analysis demonstrated acetylcholinesterase activity at the nerve-muscle interface, confirming the formation of motor end plates de novo. CONCLUSIONS: We demonstrated that neurotization is capable of reinnervating de novo end plates in chronically denervated muscle. Our data do not support the hypothesis that direct muscle neurotization is superior to nerve repair for functional restoration of chronically denervated muscle. However, as the duration of denervation increases, the difference between outcomes of the neurotization and repair group narrows, suggesting that neurotization may offer a viable surgical alternative in the setting of prolonged denervation.

Osteoporotic vertebral fractures and collapse with intravertebral vacuum sign (Kümmel's disease).

The intravertebral vacuum phenomenon was first described by Kümmel and is also known as delayed vertebral collapse or vertebral pseudarthrosis. Clinically, it occurs in approximately 10% of vertebral osteoporotic fractures, mainly in the thoracolumbar zone, is accentuated on extension views and associated with benign fractures. Most patients are neurologically intact, and continued pain is a common symptom that responds well to stabilization. Various theories exist in the literature about the pathogenesis; data support a combination of ischemia and psuedarthrosis. The ultimate treatment plan must be individualized and involve decompression of neurologic elements--when present--and sufficient stabilization, which varies according to surgeon preference and the patient's combordities.

Chronic infections of the spine: surgical indications and treatments.

UNLABELLED: Chronic vertebral osteomyelitis is a disease of substantial morbidity. Although uncommon to most spinal surgeons, the incidence of pyogenic and granulomatous spondylitis worldwide is on the rise. Although antibiotic therapy remains the initial treatment for most patients, surgical debridement with or without stabilization may be required for effective eradication of the disease. Indications for surgery in pyogenic and granulomatous osteomyelitis include the need to obtain a bacteriologic diagnosis when other methods have failed, the presence of a clinically significant abscess, an infection refractory to prolonged nonoperative treatment, cord compression with considerable neurologic deficit, and substantial deformity or spinal instability. Currently, controversy remains regarding the timing of surgery, the approach used, and the use of instrumentation. We reviewed the contemporary literature available through the Medline database, focusing on larger case series and, when existing, prospective randomized trials. The rationale for surgical treatment of the most common pathogens (eg, Mycobacterium tuberculae and Staphylococcus aureus) is reviewed. Commonly, anterior debridement with or without posterior instrumentation is used for cases of advanced disease, but more limited approaches may have a role in less severe cases or patients unable to tolerate extensive surgery. LEVEL OF EVIDENCE: Therapeutic study, level III (systematic review of level III studies). Please see the Guidelines for Authors for a complete description of levels of evidence.

Pott disease in the thoracolumbar spine with marked kyphosis and progressive paraplegia necessitating posterior vertebral column resection and anterior reconstruction with a cage.

STUDY DESIGN: Case report. OBJECTIVES: To report on a patient with Pott disease, progressive neurologic deficit, and severe kyphotic deformity, who had medical treatment fail and required posterior/anterior decompression with instrumented fusion. Treatment options will be discussed. SUMMARY OF BACKGROUND DATA: Tuberculous spondylitis is an increasingly common disease worldwide, with an estimated prevalence of 800,000 cases. METHODS: Surgical treatment consisting of extensive posterior decompression/instrumented fusion and 3-level posterior vertebral column resection, followed by anterior debridement/fusion with cage reconstruction. RESULTS: Neurologic improvement at 6-month follow-up (Frankel B to Frankel D), with evidence of radiographic fusion. CONCLUSIONS: A 70-year-old patient with progressive Pott paraplegia and severe kyphotic deformity, for whom medical treatment failed is presented. A posterior vertebral column resection, multiple level posterior decompression, and instrumented fusion, followed by an anterior interbody fusion with cage was used to decompress the spinal cord, restore sagittal alignment, and debride the infection. At 6-month follow-up, the patient obtained excellent pain relief, correction of deformity, elimination of the tuberculous foci, and significant recovery of neurologic function.