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

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.

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

STUDY DESIGN: Retrospective analysis of radiological images. PURPOSE: To determine the prevalence of lumbosacral transition vertebra (LSTV) and to study its significance with respect to clinically significant spinal symptoms, disc degeneration and herniation. OVERVIEW OF LITERATURE: LSTV is the most common congenital anomaly of the lumbosacral spine. The prevalence has been debated to vary between 7% and 30%, and its relationship to back pain, disc degeneration and herniation has also not been established. METHODS: The study involved examining the radiological images of 3 groups of patients. Group A consisted of kidney urinary bladder (KUB) X-rays of patients attending urology outpatient clinic. Group B consisted of X-rays with or without magnetic resonance images (MRIs) of patients at-tending a spine outpatient clinic, and group C consisted of X-rays and MRI of patients who had undergone surgery for lumbar disc herniation. One thousand patients meeting the inclusion criteria were selected to be in each group. LSTV was classified by Castellvi's classification and disc degeneration was assessed by Pfirrmann's grading on MRI scans. RESULTS: The prevalence of LSTV among urology outpatients, spine outpatients and discectomy patients was 8.1%, 14%, and 16.9% respectively. LSTV patients showed a higher Pfirrmann's grade of degeneration of the last mobile disc. Results were found to be significant statistically. CONCLUSIONS: The prevalence of LSTV in spinal outpatients and discectomy patients was significantly higher as compared to those attending the urology outpatient clinic. There was a definite causal relationship between the transitional vertebra and the degeneration of the disc immediately cephalad to it.
Ambulatory Care Facilities ; Back Pain ; Classification ; Diskectomy ; Humans ; Intervertebral Disc Degeneration ; Kidney ; Magnetic Resonance Imaging ; Outpatients ; Prevalence* ; Retrospective Studies ; Spine* ; Urinary Bladder ; Urology

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

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

Osteochondromas are the most common benign tumors of the bone. They mostly arise from the appendicular skeleton and present clinically in the second or third decade of life. Ostechondromas arising from the subaxial cervical spine and presenting after the 5th decade of life are extremely rare. We report a 52-year-old male patient who presented with numbness and subjective weakness of left upper and lower limbs and neck pain, and had lobulated bony hard fixed swelling in the right lower cervical paraspinal region. Radiological images revealed a bony swelling arising from C4 and C5 lamina with a cartilaginous cap and intraspinal extension. Excision biopsy with stabilisation of the spine was performed. Histopathalogical examination of the specimen confirmed the diagnosis of osteochondroma. We conclude surgical excision of such rare tumors, including the cartilaginous cap as well as the intraspinal component can reliably produce a good clinical outcome.
Aged ; Biopsy ; Diagnosis ; Humans ; Hypesthesia ; Lower Extremity ; Male ; Middle Aged* ; Neck Pain ; Osteochondroma* ; Skeleton ; Spine*

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