Numerical analysis of the mechanical behaviour of intact and implanted lumbar functional spinal units: Effects of loading and boundary conditions.

The objective of this study was to develop an improved finite element (FE) model of a lumbar functional spinal unit (FSU) and to subsequently analyse the deviations in load transfer owing to implantation. The effects of loading and boundary conditions on load transfer in intact and implanted FSUs and its relationship with the potential risk of vertebral fracture were investigated. The FE models of L1-L5 and L3-L4 FSUs, intact and implanted, were developed using patient-specific CT-scan dataset and segmentation of cortical and cancellous bone regions. The effect of submodelling technique, as compared to artificial boundary conditions, on the elastic behaviour of lumbar spine was examined. Applied forces and moments, corresponding to physiologic movements, were used as loading conditions. Results indicated that the loading and boundary conditions considerably affect stress-strain distributions within a FSU. This study, based on an improved FE model of a vertebra, highlights the importance of using the submodelling technique to adequately evaluate the mechanical behaviour of a FSU. In the intact FSU, strains of 200-400 µÎµ were observed in the cancellous bone of vertebral body and pedicles. High equivalent stresses of 10-25 MPa and 1-5 MPa were generated around the pars interarticularis for cortical and cancellous regions, respectively. Implantation caused reductions of 85%-92% in the range of motion for all movements. Insertion of the intervertebral cage resulted in major deviations in load transfer across a FSU for all movements. The cancellous bone around cage experienced pronounced increase in stresses of 10-15 MPa, which indicated potential risk of failure initiation in the vertebra.

CSF proteomics of secondary phase spinal cord injury in human subjects: perturbed molecular pathways post injury.

Recovery of sensory and motor functions following traumatic spinal cord injury (SCI) is dependent on injury severity. Here we identified 49 proteins from cerebrospinal fluid (CSF) of SCI patients, eight of which were differentially abundant among two severity groups of SCI. It was observed that the abundance profiles of these proteins change over a time period of days to months post SCI. Statistical analysis revealed that these proteins take part in several molecular pathways including DNA repair, protein phosphorylation, tRNA transcription, iron transport, mRNA metabolism, immune response and lipid and ATP catabolism. These pathways reflect a set of mechanisms that the system may adopt to cope up with the assault depending on the injury severity, thus leading to observed physiological responses. Apart from putting forward a picture of the molecular scenario at the injury site in a human study, this finding further delineates consequent pathways and molecules that may be altered by external intervention to restrict neural degeneration.

The rare aggressive osteoblastoma in a two year old child in an unusual localization.

A rare bone tumor of 3rd metacarpal bone in a male child aged 2 years is being described. The patent presented with a gradually increasing, painful swelling over the dorsum of right hand which radiologically revealed an expansile, radioluscent mass, in 3rd metacarpal shaft with cortical destruction. The clinic-radiological differential diagnosis was aggressive cartilage tumor or an osteomyelitis. Histological examination of surgical biopsy material revealed randomly arranged woven bone lined by epithelioid osteoblast and after correlating the clinic-radiological features the diagnosis was an aggressive osteoblastoma. Appropriate diagnosis of such a rare tumor in an unusual location and age group facilitate adequate management by surgery alone without radiotherapy or chemotherapy.

Electromyographic validation study of rotator cuff in recurrent anterior dislocation of shoulder treated with modified Boytchev procedure.

Modified Boytchev is one of good operative procedure for recurrent anterior dislocation of shoulder in terms of recurrence and loss of motion of shoulder by rerouting the conjoined tendon deep to subscapularis. To know the possible mechanism of this procedure, electromyographic study showed the significantly greater recruitment pattern in subscapularis as compared to pre-operative subscapularis electromyographic pattern and other rotator cuff muscles.

The concept of valgus under reduction in fixation of displaced trochanteric femoral fractures with sliding hip screw.

Sixty-six patients (male 30, female 36) with displaced trochanteric fractures (according to AO classification = A1.2, A1.3 A2 and A3 groups) have been studied during the period November 2011 to September 2013. Displaced stable fractures also have been included because in grossly osteoporotic elderly patients, this may lead to gross uncontrolled collapse and act like unstable fracture and it has fixation failure rate of 1-9%. Mean age of the patients was 8.5 years. DHS was used for the patients with intact lateral cortex and used DCS for the fractures with comminuted lateral cortex extending up to vastus ridge and also in A3 types. The screw placement was inferior to central in AP view, and central to posterior in lateral view. In AP view under reduction was done with slight lateralisation and upward displacement of distal fragment and fixed with DHS/DCS with affected limb in abduction 30 to 40 degree to achieve valgus angle of about 160-170. In lateral view neck shaft angle was maintained to 160-180 degree, on higher side, avoiding retroversion. All the parameters of fixation failure like varus displacement, retroversion, external rotation, medialisation, cut out, collapse and shortening of limb, pullout side plate and implant failure have been studied. Only the patients treated with valgus under-reduction have been included in this study. We conclude that under-reduction in valgus position gives excellent posteromedical stability as it provides controlled collapse as the calcar fragment is abutting against the medial femoral shaft (as in Weyne County reduction) and also prevents shortering by valgus reduction (Parker).

Neglected Monteggio lesion--is full recovery expected?

Eleven cases of chronic (neglected) Monteggia lesion, presented after 6 months of injury, were treated with angulation distraction osteotomy of ulna and annular ligament reconstruction from January 2003 to June 2008 atNRS Medical College, Kolkata. Patients were followed up for a mean period of 56 months, assessed on deformity, pain, function and range of motion. There were terminal restriction of at least 15 degrees pronation in each case.

Operative outcome of unstable lower cervical fracture dislocation by lateral mass screw fixation or anterior plating.

From February 2009 to September 2012, 15 patients (13 males, 2 females; age range, 18-55 years) with the lower cervical fracture dislocation were treated at NRS Medical College, Kolkata. The fracture dislocation occurred in the following cervical segments: C5 (n = 8), C7 (n = 3), C4 (n = 2), and C6 (n = 2). Forteen patients were associated with neurological deficit graded according to ASIA impairment scale. The time interval between Injury and operation was from 3 to 22 days. Eight patients underwent anterior fusion with anterior locked-cervical plate fixation; 7 patients underwent posterior fusion and the lateral mass screw fixation. During each follow-up clinical and radiological parameters were measured; bone fusion and internal fixation condition were observed by x-ray and the neurological recovery was measured by ASIA impairment scale. Follow-up duration was from 3 months to 30 months in different patients which revealed fusion between vertebrae and significant neurological recovery. The fusion time was 4 to 6 months and there was also no instability of vertebrae or loosening of the internal fixation at 12 months. The selection of operative treatment of subaxial cervical spine injury depends upon neurological and radiological criteria. Both posterior and anterior surgical approaches are viable alternatives for treating subaxial spine injuries with different indication and risk profiles. In case of incomplete neurological injury there is significant improvement. Operative treatment certainly decreases the complications related to prolonged immobilisation in recovery phase by making the patient mobile early.

Modified Boytchev procedure for treatment of recurrent anterior dislocation of shoulder.

BACKGROUND: More than 200 different operations have been described for the treatment of recurrent anterior dislocation of shoulder. The Modified Boytchev procedure employs rerouting of the detached tip of coracoid process with its attached conjoined tendon (short head of biceps and coracobrachialis) deep to subscapularis and reattaches to its anatomical location. We conducted a study on evaluation of long-term effect of modified Boytchev procedure and to compare our results with other studies published in literature. MATERIALS AND METHODS: Since June 2002, modified Boytchev procedure was performed on 48 patients, who presented with recurrent anterior dislocation. 45 were men and 3 were women and were in the age group of 18-40 years (mean 27.83±4.95 years). Forty patients were affected on the dominant side and rest on the non-dominant side. The mean number of dislocations in these patients was 18.22±12.08. The mean followup period was 58.13±19.06 months (range 18-96 months). The patients were evaluated by visual analogue score, modified American Shoulder and Elbow Surgeon's Score (ASES), and Single Assessment Numeric Evaluation (SANE) score at the last followup. RESULTS: All the patients regained almost preoperative range of forward flexion at the last followup. In the preoperative period the mean external rotation deficit at 0° and at 90° of abduction was 13.22°±5.16° and 18.06°±6.50°, respectively. At the last followup, the mean external rotation deficit at 0° and at 90° of abduction was 8.06°±2.47° and 8.95°±2.07°, respectively. This improvement in external rotation deficit was statistically significant (P<.05). Preoperative scores were compared with the most recent followup scores for all variables with use of a paired t test. All patients had significant improvement in visual analogue score, modified American Shoulder and Elbow Surgeon's Score (ASES), and Single Assessment Numeric Evaluation (SANE) score at the last followup. Four of the patients developed superficial infection which got resolved after treating with antibiotics, and two of the patients developed transient musculocutaneous nerve paresis. There was no radiological evidence of loosening and migration of coracoid screw or any glenohumeral arthritis on subsequent followup of skiagrams in any of our patients. CONCLUSION: Modified Boytchev procedure is an efficacious and technically simple procedure to treat recurrent anterior dislocation of shoulder.

Evaluation of pedicular screw fixation in dorsolumbar spinal injury.

Twenty-five patients with dorsolumbar spinal injury was treated by pedicular screw fixation along with direct or indirect decompression within 1 1/2 years period. Eighteen patients with incomplete neurodeficit had some amount of neurological recovery in terms of ASIA impairment scale but no neurological recovery was seen in 6 patients with complete neurological injury. Mean correction of kyphotic angle was 11.76 degrees. Mean postoperative increase in anterior vertebral body height was 43%. Complications like bed sore, superficial wound infections and peroperative dural tear were seen but all of which were treated successfully. Neurological deterioration after operation, screw pull out and implant failure were seen in none. This study indicates that short segment pedicular screw fixation is a safe and effective method for treatment of unstable spinal injury.

Displaced middle-third fractures of the clavicle-operative management.

Displaced midclavicular fractures resulting in malunion with shortening and rotational deformity does not remodel in adults and incidence of non-union in displaced midshaft clavicular fractures is between 10-15% especially in those with an initial shortening of >20 mm.We have treated 10 patients of displaced middle-third clavicle fracture by open reduction and internal fixation with plate and screws and found it to be very effective in respect to rehabilitation, union and cosmesis.

Percutaneous fixation of displaced intra-articular calcaneal fracture.

Operative treatment modalities for calcaneal fracture are still controversial. The outcome of intra-articular calcaneal fracture is mainly influenced by the soft tissue and the subtalar joint. Percutaneous method of internal fixation has been attempted to avoid the problems. Patients with displaced intra-articular calcaneal fracture types IIA, IIB and IIC were treated by initial distraction of subtalar joint, restoration the of subtalar joint, reduction of lateral expansion and finally fixation with screws percutaneously. Twenty-two patients with 26 calcaneal fractures were included. After a mean follow-up of 2 1/2 years and with American Orthopaedic Foot and Ankle Society hind foot score 82 points out of 100. Percutaneous fixation of calcaneum fracture is good alternative method in types IIA, IIB and IIC and selective type III fractures.