STUDY DESIGN: Biomechanical study. PURPOSE: To determine the effect of density, insertion angle and reinsertion on pull-out strength of pedicle screw in single and two screw-rod configurations. OVERVIEW OF LITERATURE: Pedicle screw pull-out studies have involved single screw construct, whereas two screws and rod constructs are always used in spine fusions. Extrapolation of results using the single screw construct may lead to using expensive implants or increasing the fusion levels specifically in osteoporotic bones. METHODS: Single screw and two screw pull-out strength tests were carried out according to American Society for Testing and Materials F 543-07 on foam models to test the effect of density, insertion angle and reinsertion using poly axial pedicle screws. RESULTS: Bone density was the most significant factor deciding the pull-out strength in both single and two screw constructs. The difference in pull-out strength between single screw and two screw configurations in extremely osteoporotic bone model (80 kg/m3) was 78%, whereas in the normal bone model it was 48%. Axial pull-out value was highest for the single screw configuration; in the two screw configuration the highest pull-out strength was at 10°-15°. There was an 18% reduction in pull-out strength due to reinsertion in single screw configuration. The reinsertion effect was insignificant in the two screw configuration. CONCLUSIONS: A significant difference in response of various factors on holding power of pedicle screw between single and two-screw configurations is evident. The percentage increase in pull-out strength between single and two screw constructs is higher for osteoporotic bone when compared to normal bone. Reinsertion has no significant effect on pull-out strength in the two screw rod configuration.
Bone Density ; Osteoporosis ; Pedicle Screws* ; Spine

STUDY DESIGN: Biomechanical study. PURPOSE: To determine the effect of density, insertion angle and reinsertion on pull-out strength of pedicle screw in single and two screw-rod configurations. OVERVIEW OF LITERATURE: Pedicle screw pull-out studies have involved single screw construct, whereas two screws and rod constructs are always used in spine fusions. Extrapolation of results using the single screw construct may lead to using expensive implants or increasing the fusion levels specifically in osteoporotic bones. METHODS: Single screw and two screw pull-out strength tests were carried out according to American Society for Testing and Materials F 543-07 on foam models to test the effect of density, insertion angle and reinsertion using poly axial pedicle screws. RESULTS: Bone density was the most significant factor deciding the pull-out strength in both single and two screw constructs. The difference in pull-out strength between single screw and two screw configurations in extremely osteoporotic bone model (80 kg/m3) was 78%, whereas in the normal bone model it was 48%. Axial pull-out value was highest for the single screw configuration; in the two screw configuration the highest pull-out strength was at 10°-15°. There was an 18% reduction in pull-out strength due to reinsertion in single screw configuration. The reinsertion effect was insignificant in the two screw configuration. CONCLUSIONS: A significant difference in response of various factors on holding power of pedicle screw between single and two-screw configurations is evident. The percentage increase in pull-out strength between single and two screw constructs is higher for osteoporotic bone when compared to normal bone. Reinsertion has no significant effect on pull-out strength in the two screw rod configuration.
Bone Density ; Osteoporosis ; Pedicle Screws* ; Spine

Spinal hydatid cyst is a rare occurrence in non endemic countries. We present a case of recurrent lumbar hydatid disease in a 21-year-old male who following initial treatment had a good functional outcome and healing for 8 years, following which he came back with complaints of low back ache and neurological deficit. Patient underwent a second surgery with global debridement of L3-L5 vertebrae followed by medical management for two years. He had a good surgical outcome with recovery from the neurological deficit. Patient has returned to his routine activities and is being reviewed every year; there is no evidence of recurrence in the past 3 years. To the best of our knowledge recurrence after 8 years of initial treatment, followed by good clinical and radiological outcome for 3 years after surgery and treatment of the recurrence has not been reported in literature.
Albendazole ; Debridement ; Echinococcosis ; Follow-Up Studies ; Humans ; Low Back Pain ; Lumbar Vertebrae ; Male ; Porphyrins ; Recurrence ; Spine

Exostosis of the rib with neural foraminal extension as a cause of spinal cord compression and scoliosis has to the best of our knowledge not been reported. We describe a young male with hereditary multiple exostosis who presented with a spastic gait, lower limb weakness and a deformity of the upper back. Radiographic imaging revealed a lesion arising from the left second rib which was encroaching the spinal canal and a scoliotic deformity of the upper thoracic spine. Through a single T shaped posterior approach he underwent a decompressive laminectomy of T1 and T2 vertebra and excision of the lesion. The diagnosis of osteochondroma was confirmed by histopathological studies. He was followed up at one year when his neurological condition had returned to normal however the scoliosis had increased.
Congenital Abnormalities ; Exostoses ; Exostoses, Multiple Hereditary ; Gait Disorders, Neurologic ; Humans ; Laminectomy ; Lower Extremity ; Male ; Osteochondroma ; Ribs ; Scoliosis ; Spinal Canal ; Spinal Cord ; Spinal Cord Compression ; Spine

Results: Pullout strength decreased by 36% when the size of the revision screw was increased by 1 mm, while it increased by 35% when the size of the revision screw was increased by 2 mm compared to the index screw value. While the morphologies of the load paths were similar in all cases, they differ between the two groups: the larger screw responded with generally elevated stiffer path than the smaller screw, suggesting that revision surgery using a larger screw has more purchase along the inserted body-pedicle axis. Conclusions A larger screw enhances strength and increases biomechanical stability in revision surgeries, although the final surgical decision is made by the clinician, which includes the patient’s anatomy and associated characteristics.

STUDY DESIGN: Retrospective clinical series. PURPOSE: To assess whether titanium cages are an effective alternative to tricortical iliac crest bone graft for anterior column reconstruction in patients with active pyogenic and tuberculous spondylodiscitis. OVERVIEW OF LITERATURE: The use of metal cages for anterior column reconstruction in patients with active spinal infections, though described, is not without controversy. METHODS: Seventy patients with either tuberculous or pyogenic vertebral osteomyelitis underwent a single staged anterior debridement, reconstruction of the anterior column with titanium mesh cage and adjuvant posterior instrumentation. The lumbar spine was the predominant level of involvement. Medical co-morbidities were seen in 18 (25.7%) patients. A significant neurological deficit was seen in 32 (45.7%) patients. At follow up patients were assessed for healing of disease, bony fuson, and clinical outcome was assessed using Macnab's criteria. RESULTS: Final follow up was done on 64 (91.4%) patients at a mean average of 25 months (range, 12 to 110 months). Pathologic organisms could be identified in 42 (60%) patients. Forty two (60%) patients had histopathological findings consistent with tuberculosis. Thirty of 32 (93.7%) patients showed neurological recovery. The surgical wound healed uneventfully in 67 (95.7%) patients. Bony fusion was seen in 60 (93.7%) patients. At final follow up healing of infection was seen in all patients. As per Macnab's criteria 61 (95.3%) patients reported a good to excellent outcome. CONCLUSIONS: Inspite of the theoretical risks, titanium cages are a suitable alternative to autologous tricortical iliac crest bone graft in patients with active spinal infections.
Debridement ; Discitis ; Follow-Up Studies ; Humans ; Osteomyelitis ; Retrospective Studies ; Spine ; Titanium ; Transplants ; Tuberculosis

Chondrosarcomas are malignant cartilage forming tumours. They form the second most common primary malignant tumour involving the vertebral axis. We present a rare presentation of a secondary chondrosarcoma from the spinous process of lumbar vertebra and discussed its management. The main emphasis is on the rare presentation and the need for awareness and suspicion of the pathology.
Axis, Cervical Vertebra ; Cartilage ; Chondrosarcoma ; Spine

STUDY DESIGN: Non-concurrent prospective study. PURPOSE: To determine the functional outcome after open 'fragment' discectomy for recurrent lumbar disc herniation, and to analyze the factors that may affect the outcome. OVERVIEW OF LITERATURE: Literature search revealed only four studies where the factors affecting the outcome of a revision surgery for recurrent disc herniation have been evaluated. None of these studies analyzed for diabetes, disc degeneration and facet arthropathy. We have analyzed these features, in addition to the demographic and clinical factors. METHODS: Thirty-four patients who underwent the procedure were followed up for an average period of 27.1 months. The Japanese Orthopaedic Association (JOA) score and Oswestry disability index (ODI) were used to assess the functional outcome. Age, gender, smoking, diabetic status, duration of recurrent symptoms, the side of leg pain, level and type of disc herniation, degree of disc degeneration on magnetic resonance imaging, and facet joint arthritis before first and second surgeries, were analyzed as factors affecting the outcome. RESULTS: The average Hirabayashi improvement in JOA was 56.4%. The mean preoperative ODI was 74.5% and the mean ODI at final follow-up was 32.2%, the difference being statistically significant (p<0.01). Patients with diabetes, all of whom had poor long term glycemic control, were found to have a poor outcome in terms of ODI improvement (p=0.03). CONCLUSIONS: Open fragment discectomy is a safe and effective surgical technique for the treatment of recurrent disc herniation. However, patients with uncontrolled diabetes may have a less favorable outcome.
Arthritis ; Asian Continental Ancestry Group ; Diabetes Mellitus ; Diskectomy ; Follow-Up Studies ; Humans ; Intervertebral Disc Degeneration ; Leg ; Low Back Pain ; Magnetic Resonance Imaging ; Prospective Studies* ; Radiculopathy ; Smoke ; Smoking ; Zygapophyseal Joint

Gorham's disease is a rare disorder characterized by clinical and radiological disappearance of bone by proliferation of non-neoplastic vascular tissue. The disease was first reported by Jackson in 1838 in a boneless arm. The disease was then described in detail in 1955 by Gorham and Stout. Since then, about 200 cases have been reported in the literature, with only about 28 cases involving the spine. We report 2 cases of Gorham's disease involving the spine and review related literature to gain more understanding about this rare disease.
Arm ; Rare Diseases ; Spine

STUDY DESIGN: Retrospective clinical series. PURPOSE: To study the clinical, functional and radiological results of patients with tuberculous spondylitis with and without paraplegia, treated surgically using the "Extended Posterior Circumferential Decompression (EPCD)" technique. OVERVIEW OF LITERATURE: With the increasing possibility of addressing all three columns by a single approach, posterior and posterolateral approaches are gaining acceptance. A single exposure for cases with neurological deficit and kyphotic deformity requiring circumferential decompression, anterior column reconstruction and posterior instrumentation is helpful. METHODS: Forty-one patients with dorsal/dorsolumbar/lumbar tubercular spondylitis who were operated using the EPCD approach between 2006 to 2009 were included. Postoperatively, patients were started on nine-month anti-tuberculous treatment. They were serially followed up to thirty-six months and both clinical measures (including pain, neurological status and ambulatory status) and radiological measures (including kyphotic angle correction, loss of correction and healing status) were used for assessment. RESULTS: Disease-healing with bony fusion (interbody fusion) was seen in 97.5% of cases. Average deformity (kyphosis) correction was 54.6% in dorsal spine and 207.3% in lumbar spine. Corresponding loss of correction was 3.6 degrees in dorsal spine and 1.9 degrees in the lumbar spine. Neurological recovery in Frankel B and C paraplegia was 85.7% and 62.5%, respectively. CONCLUSIONS: The EPCD approach permits all the advantages of a single or dual session anterior and posterior surgery, with significant benefits in terms of decreased operative time, reduced hospital stay and better kyphotic angle correction.
Congenital Abnormalities ; Decompression* ; Humans ; Length of Stay ; Operative Time ; Paraplegia* ; Retrospective Studies ; Spine ; Spondylitis*