Distribution of geochemical forms and bioavailability of phosphorus in the surface sediments of Beypore Estuary, southwestern coast of India.

Nutrient management in shallow transitional aquatic systems is very complex due to the sediment-water exchange, especially for phosphorus. The present study tries to get an in-depth understanding of the distribution of geochemical forms of phosphorus in the surface sediments of Beypore Estuary, a tropical estuarine system in southwest India, which has been subjected to immense climate change in recent times. Total phosphorus in the sediments was found to be abysmally lower (76.8 to 889.12 µg/g) than those reported for other tropical estuaries. Organic-bound phosphorus constituted the majority of the total phosphorus in the sediments, and unlike other tropical estuaries, iron-bound and calcium-bound phosphorus were minor fractions in the study region. However, the bioavailable phosphorus was consistent throughout the study period and varied from 16.5 to 51.0% of total phosphorus. This reveals the active phosphorus buffering in the Beypore Estuary even in the absence of an external source. Statistical evaluation of two contrasting seasons (low and high runoff periods) could illustrate the major biogeochemical pathways for phosphorus in the Beypore Estuary. This study highlights the significant role of hydrographical parameters in regulating phosphorus bioavailability in this estuary; therefore, any modifications to the same by climate change could make nutrient management even more challenging.

Ultrasonic bone scalpel in spine surgery.

Background: Spine surgery has always been considered technically demanding even in the hands of the most experienced surgeon on account of close proximity of vital soft tissue structures. Technical advancements over the last few decades have been crucial for the progress of this complex speciality which not only increased the surgical accuracy, but patient safety as well. Ultrasonic devices are one such innovation based on piezoelectric vibrations, patented by Fernando Bianchetti, Domenico Vercellotti, and Tomaso Vercellotti in 1988. Methods: We did an extensive literature search on ultrasonic devices and their applications in the field of spine surgery. Results: We present the various ultrasonic bone devices available including their physical, technologic and clinical aspects in spine surgery. We also attempt to cover the limitations and future advances of Ultrasonic bone scalpel (UBS) in particular, which would be interesting and informative for any spine surgeon who is novice in this field. Conclusion: UBS has been found to be safe and effective in all forms of spine surgeries offering distinct advantages over conventional instruments, although limited by an inherent learning curve.

C7 distal fixation anchor and its influence on sagittal profile in posterior cervical fusion; a retrospective analysis of 44 cases.

Study design: Retrospective. Purpose: In multilevel posterior cervical fusion, whether to stop distal fixation at C7 or T1, remains a matter of debate. We aimed to assess clinical feasibility of C7 as distal fixation point and sought to compare complication rates and radiological outcome between lateral mass screws and pedicle screws at C7. Overview of literature: Current literature remains inconclusive regarding need for thoracic extension of instrumentation in multilevel posterior cervical fusion. Methods: We did a retrospective review of 44 consecutive patients who underwent posterior instrumented cervical decompression and fusion for degenerative cervical myelopathy with C7 as distal fixation point, and a minimum follow-up period of two years. We had two groups of patients based on C7 instrumentation. Group 1: Lateral mass screw fixation. Group 2: Pedicle screw fixation. Primary outcome: Post-operative clinico-radiological evaluation of whole study population Secondary outcome: Comparison of complication rates and radiological outcome between groups 1 and 2. Results: Mean age was 58.06 ± 14.4 years with average follow-up duration of 35.4 ± 4.5 months. There were 18 patients in Group 1 and 26 patients in Group 2. Mean pre-operative mJOA score was 10.51 and post-operative mJOA score was 15.74 with mean recovery rate (RR) 69.82%, of which 30 patients (70.23%) had good recovery and 14 patients (29.77%) had fair recovery at final follow up. The two groups didn't show any significant difference in complication rates and outcome. Conclusion: C7 as distal fixation anchor is safe and effective in maintaining cervical sagittal balance following multilevel posterior cervical fusion. C7 lateral mass screws are found to be equally efficacious as pedicle screws in preventing worsening of sagittal profile.

Spinal Melorheostosis: A Rare Cause for Thoracic Radiculopathy.

BACKGROUND: Symptomatic spinal melorheostosis is a rare entity, and its surgical management is even rarer. Our objective is to highlight the importance of considering spinal melorheostosis among the differential diagnosis of thoracic radiculopathy. METHODS: We report a case of melorheostosis involving the T9 vertebra presenting with unilateral radicular pain managed surgically by decompression and posterior stabilization. RESULTS: Our patient had complete symptomatic relief following surgical resection without any perioperative complications. CONCLUSIONS: Spinal melorheostosis, although rare, forms an important differential diagnosis in patients presenting with thoracic radiculopathy where surgical management can be a viable option in cases refractory to conservative treatment. LEVEL OF EVIDENCE: 5.

Does Sarcopenia Increase the Risk for Fresh Vertebral Fragility Fractures?: A Case-Control Study.

STUDY DESIGN: Case-control study. PURPOSE: Sarcopenia is an age associated condition characterized by decrease in muscle mass, strength, and physical performance. We aimed to investigate whether sarcopenia increased the risk of vertebral fragility fractures among the elderly. OVERVIEW OF LITERATURE: Initial reports on sarcopenia suggest its contribution to the development of vertebral fragility fractures. However, recent studies showed contradictory findings. METHODS: Fifty-one consecutive patients with vertebral fragility fractures and matched controls without fractures were evaluated for sarcopenia, T-score, body mass index, and presence of preexisting vertebral fractures. Sarcopenia was diagnosed as total psoas cross-sectional area (TPA) 2 standard deviations below normative value from normal young adults and decreased handgrip strength (26 kg for men and 18 kg for women). Univariate and multivariate analyses were performed using the fresh fracture occurrence as the dependent variable. RESULTS: Sarcopenia was confirmed in 29.4% and 7.8% of cases and controls (p=0.005), respectively; 56.8% and 13.7% of cases and controls had previous vertebral fractures. Sarcopenia prevalence was greater among those with previous fractures (38% vs. 7.6%; odds ratio, 7.76; p<0.001). TPA was lower among the cases (1,278 mm2 vs. 1,569 mm2 , p=0.001) and those with previous fractures (1,168 mm2 vs. 1,563 mm2 , p<0.001). Handgrip strength was greater among those without previous fractures (19.6 kg vs. 16.3 kg, p=0.05). In multivariate analysis, sarcopenia was not identified as a significant predictor of fresh fractures whereas previous fractures and lower T-score were found to be significant. CONCLUSIONS: Sarcopenia is not an independent risk factor for fresh vertebral fragility fractures in the elderly.

Fractionation and bioavailability of phosphorus in a tropical estuary, Southwest India.

Phosphorus fractionation was employed to find the bioavailability of phosphorus and its seasonal variations in the Panangad region of Cochin estuary, the largest estuarine system in the southwest coast of India. Sequential extraction of the surficial sediments using chelating agents was taken as a tool for this. Phosphate in the water column showed seasonal variations, with high values during the monsoon months, suggesting external runoff. Sediment texture was found to be the main factor influencing the spatial distribution of the geochemical parameters in the study region. Similarly, total phosphorus also showed granulometric dependence and it ranged between 319.54 and 2,938.83 µg/g. Calcium-bound fraction was the main phosphorus pool in the estuary. Significant spatial variations were observed for all bioavailable fractions; iron-bound inorganic phosphorus (5.04-474.24 µg/g), calcium-bound inorganic phosphorus (11.16-826.09 µg/g), and acid-soluble organic phosphorus (22.22-365.86 µg/g). Among the non-bioavailable phosphorus, alkali-soluble organic fraction was the major one (51.92-1,002.45 µg/g). Residual organic phosphorus was comparatively smaller fraction (3.25-14.64% of total). The sandy and muddy stations showed distinct fractional composition and the speciation study could endorse the overall geochemical character. There could be buffering of phosphorus, suggested by the increase in the percentage of bioavailable fractions during the lean pre-monsoon period, counteracting the decreases in the external loads. Principal component analysis was employed to find the possible processes influencing the speciation of phosphorus in the study region.