Influence of Retrogression and Re-aging on the Exfoliation Corrosion Behavior of AA 7085 Sheets

( Ajay Krishnan ),( V. S. Raja ),( A. K. Mukhopadhyay ) 한국부식방식학회(구 한국부식학회) 2016 Corrosion Science and Technology Vol.15 No.4

An attempt has been made to understand the influence of retrogression and re-aging (RRA) on the exfoliation corrosion behaviour of AA 7085 alloy in comparison with the peak aged condition (PA). Immersion tests using ASTM G34 and studies involving electrochemical impedance spectroscopy showed that the RRA treated alloy provided higher resistance to exfoliation corrosion than the PA treated alloy. The improved resistance was attributed to the enhanced Cu content and the discontinuous nature of the grain boundary precipitate, which was revealed through transmission electron microscopy.

The Relationship of Facet Joint Orientation and Tropism with Lumbar Disc Herniation and Degenerative Spondylolisthesis in the Lower Lumbar Spine

Devanand Degulmadi,Bharat Dave,Ajay Krishnan,Denish Patel 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.1

Study design: Retrospective study. Purpose: This study aimed to clarify the relationship of both facet tropism (FT) and the sagittally aligned facet (SAF) joint with lumbar disc herniation (LDH) and degenerative spondylolisthesis (DS). Overview of Literature: Despite several studies conducted, there is no consensus on the association of the SAF joint and FT with DH and DS. Methods: Between June 2015 and December 2017, magnetic resonance imaging scans of 250 consecutive patients who underwent surgery for LDH and DS were analyzed. The facet angles at all the lower lumbar levels were calculated, and SAF and FT were noted. The relationship between the side of disc herniation and that of the SAF joint were also determined. Statistical analysis was performed, and the relation of SAF and FT to LDH and DS was noted. Results: We observed a positive relationship between SAF and LDH at L4–5 and L5–S1 with a p -value of 0.02 (<0.05). FT demonstrated a positive association with LDH at L4–5 (p =0.047) but not at L3–4 or L5–S1. SAF demonstrated a positive relationship with DS at L3–4 (p <0.001) but not at L3–4 or L5–S1. FT demonstrated a significant relation with DS at L4–5 (p <0.001), whereas no positive association was observed at L3–4 and L5–S1. Conclusions: The L4–5 level demonstrated a significant association with SAF and FT in LDH and DS. Moreover, SAF at L5–S1 demonstrated a positive association with LDH. These findings provide useful information for future longitudinal studies to elucidate the possible causes for such phenomena.

The Effect of Head Loading on Cervical Spine in Manual Laborers

Dave Bharat R.,Krishnan Ajay,Rai Ravi Ranjan,Degulmadi Devanand,Mayi Shivanand 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.1

Study Design: A prospective case–control study.Purpose: To determine the effect of axial loading on the cervical spine when weights are carried on the head.Overview of Literature: Traditionally, carrying weights on the head has been a common practice in developing countries. The laborers working in agriculture, construction, and other industries, as well as porters at railway platforms, are required to lift heavy weights. Since controversy exists regarding carrying weights on the head, we decided to evaluate its effect on the cervical spine.Methods: The study comprised 62 subjects. Of this number, 32 subjects (group A) were unskilled laborers from the construction industry; the other 30 subjects (group B) were in the control group and had never previously carried heavy weights on their heads. Cervical spine radiographs were taken for all the 62 subjects. Subjects in group A were asked to carry a load (approximately 35 kg) on their heads and walk for about 65 m, with their cervical spine radiographs taken afterward.Results: The mean ages of patients in groups A and B were 27.17 and 25.75 years, respectively. The mean cervical lordosis observed in group A (18.96°) was dramatically less compared with group B (25.40°), showing a further decrease in head loading (3.35°). Five subjects had a reversal of lordosis (−5.61°). A statistically significant reduction in disc height and listhesis was observed when the load was carried on the head with a further decrease after walking with the load. Accelerated degenerative changes, particularly affecting the upper cervical spine, were observed in head loaders.Conclusions: Carrying a load on the head leads to accelerated degenerative changes, which involve the upper cervical spine more than the lower cervical spine and predisposes it to injury at a lower threshold. Thus, alternative methods of carrying loads should be proposed.

Demographics of Thoracolumbar Fracture in Indian Population Presenting to a Tertiary Level Trauma Centre

Ketan Khurjekar,Shailesh Hadgaonkar,Ajay Kothari,Rishikesh Raut,Vibhu Krishnan,Ashok Shyam,Parag Sancheti 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.3

Study Design: Prospective, cross-sectional, observational study. Purpose: Spine traumata are devastating injuries, which may result in serious disabilities and dire consequences. The current study involves a detailed analysis and description of patients, who were operated at a tertiary care, urban level 1 Spine Centre in India. Overview of Literature: Various studies in literature have discussed the epidemiology and patterns of these injuries in trauma patients. However, literature describing the demographic profile and distribution of these traumata in the Indian population is scarce. Methods: The current study was conducted as a prospective trial involving patients, who were treated at our Spine Centre in India between July 2009 to December 2012. We studied 92 patients with thoraco-lumbar spine fracture, who were operated with short or long segment posterior stabilization. Epidemiological details, pre- and post-hospitalisation care received and other injury pattern factors were studied. Results: Fall from height (46 patients, 50%) was the most common mechanism observed in the patients. Sixty-three percent injuries belonged to AO type A fractures, while 16.2% and 19.4% of the patients had suffered from AO types B and C injuries, respectively. Conclusions: We identified interesting epidemiological data and prevailing inadequacies in Emergency Spine care management in the study patients. These observations could facilitate implementation of the changes required to improve current standards of patient care.

Risk Factors and Surgical Treatment for Recurrent Lumbar Disc Prolapse: A Review of the Literature

Bharat R. Dave,Devanand Degulmadi,Ajay Krishnan,Shivanand Mayi 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.1

We aim to present the current evidence on various risk factors and surgical treatment modalities for recurrent lumbar disc herniation (rLDH). Using PubMed, a literature search was performed using the Mesh terms “recurrent disc prolapse,” “herniated lumbar disc,” “risk factors,” and “treatment.” Articles that were published between January 2010 and May 2017 were selected for further screening. A search conducted through PubMed identified 213 articles that met the initial screening criteria. Detailed analyses showed that 34 articles were eligible for inclusion in this review. Sixteen articles reported the risk factors associated with rLDH. Decompression alone as a treatment option was studied in seven articles, while 11 articles focused on different types of fusion surgery (anterior lumbar interbody fusion, posterior lumbar interbody fusion, open transforaminal lumbar interbody fusion [TLIF], and minimally invasive surgery-TLIF). Management of the rLDH requires consideration of the possible risk factors present in individual patients before primary and at the time of second surgery. Both, minimally invasive and conventional open procedures are comparably effective in relieving leg pain, and minimally invasive techniques offer advantage over the other technique in terms of tissue sparing. Non-fusion surgeries involve the risk of lumbar disc herniation re-recurrence, and the patient may require a third (fusion) surgery.

Does the Surgical Timing and Decompression Alone or Fusion Surgery in Lumbar Stenosis Influence Outcome in Cauda Equina Syndrome?

Bharat Rajendraprasad Dave,Puspak Samal,Romin Sangvi,Devanand Degulmadi,Denish Patel,Ajay Krishnan 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.2

Study Design: A retrospective comparative analysis of 64 patients with cauda equina syndrome (CES), who underwent either decompression alone (NF) or fusion (F) surgery. Purpose: We compared the outcomes and timing effects. Overview of Literature: CES can cause loss of autonomic control of vesicular function and lower limb neurological deficits. Prompt diagnosis and emergency surgery markedly improve outcome. Although decompression only is a mainstream technique, there is guarded recovery of vesicular dysfunction. Decompression ventrally in a narrow window requires manipulation of neural tissue in an already jeopardised critical canal and may accentuate irreversible damages. In F surgery, the adequate exposure leads to a lower neural manipulation. Methods: Until January 2008, we treated CES with decompression (laminectomy and/or discectomy). However, from that month forward, all our single-level CES patients have received a fusion operation. In this study, characteristic categorical variables and outcomes were analysed. Results: In a retrospective analysis of 64 patients, NF (n=37) and F (n=27) who received treatment, we found that both groups improved significantly on follow-up in all objective parameters. Although, the comparison of clinical and functional outcome data between the two groups was statistically insignificant, the average value of objective outcome such as vesicular function, low back pain (LBP), and complications was better for patients in F group compared with NF group. However, the patient satisfaction for the F group was also lower, in view of their residual symptoms and disabilities. Contrary to common perceptions, we found that the timing of surgery does not influence the recovery rate for either approach. Conclusions: Although both the techniques appear to be equally effective, the fusion approach overall showed a definite edge over non-fusion, with respect to reduced incidence of iatrogenic dural tears, LBP, and overall outcome, even despite the lower patient satisfaction.