Monosegmental fixation for the treatment of fractures of the thoracolumbar spine

Background:

A short vertebral arthrodesis has been one of the objectives of the surgical treatment of fractures of the thoracolumbar spine. We present here clinical, functional and radiographic outcome obtained after monosegmental fixation (single posterior or combined anterior and posterior) of specific types of unstable thoracolumbar fractures.

Materials and Methods:

Twenty four patients with fractures of the thoracolumbar spine submitted to monosegmental surgical treatment (Group I - 18 single posterior monosegmental fixations and Group II - 6 combined anterior and posterior fixations) were retrospectively evaluated according to clinical, radiographic and functional parameters. The indication for surgery was instability or neurological deficit. All the procedures were indicated and performed by the senior surgeon (Helton LA Defino).

Results:

The patients from group I were followed-up from 2 to 12 years (mean: 6.65±2.96). The clinical, functional and radiographic results show that a single posterior monosegmental fixation is adequate and a satisfactory procedure to be used in specific types of thoracolumbar spine fractures, The patients from group II were followed-up from 9 to 15 years (mean: 13 ± 2,09 years). On group II the results of clinical evaluation showed moderate indices of residual pain and of satisfaction with the final result. The values obtained by functional evaluation showed that 66.6% of the patients were unable to return to their previous job and presented a moderate disability index (Oswestry = 16.6) and a significant reduction of quality of life based on the SF-36 questionnaire. Radiographic evaluation showed increased kyphosis of the fixed vertebral segment during the late postoperative period, accompanied by a reduction of the height of the intervertebral disk.

Conclusion:

It is possible to stabilize the fractures which have an anterior good load-bearing capacity by a standalone posterior monosegmental fixation. However this procedure, even with an anterior support is not suitable for fracture involving the vertebral body.     

Gonadotropin-releasing hormone agonist blocks anxiogenic-like and depressant-like effect of corticotrophin-releasing hormone in mice

Corticotrophin-releasing factor (CRF) is reported to inhibit the release of gonadotropin-releasing hormone (GnRH). In addition to the endocrine effects, GnRH is reported to influence the behavior via its neuronal interactions. We therefore, hypothesized that anxiety and depression produced by CRF could be also subsequent to the decrease in GnRH. To support such possibility, we investigated the influence of GnRH agonists on CRF or CRF antagonist induced changes in social interaction time in social interaction test, and immobility time in forced swim test in mice, as the indices for anxiety and depression, respectively. Results indicated that GnRH agonists [leuprolide (20-80ng/mouse, i.c.v.), or d-Trp-6-LHRH (40-160ng/mouse, i.c.v.)] dose dependently increased social interaction time and decreased immobility time indicating anxiolytic- and antidepressant-like effect, respectively. Such effects of GnRH agonists were even evident in castrated mice, which suggest that these effects were unrelated to their endocrine influence. Administration of CRF (0.1 and 0.3nmol/mouse, i.c.v.) produced just opposite effects as that of GnRH agonist on these parameters. Further, it was seen that pretreatment with leuprolide (10 or 20ng/mouse, i.c.v.) or d-Trp-6-LHRH (20 or 40ng/mouse, i.c.v.) dose dependently antagonized the effects of CRF (0.3nmol/mouse, i.c.v.) in social interaction and forced swim test. CRF antagonist [alpha-Helical CRF (9-41), (1 or 10nmol/mouse, i.c.v.)] was found to exhibit anxiolytic- and antidepressant-like effect, and its sub-effective dose (0.1nmol/mouse, i.c.v.) when administered along with sub-threshold dose of leuprolide (10ng/mouse, i.c.v.), or d-Trp-6-LHRH (20ng/mouse, i.c.v.) also produced significant anxiolytic- and antidepressant-like effect. These observations suggest reciprocating role of GnRH in modulating the CRF induced anxiogenic- and depressant-like effects.     

Pterygium after hyperopic laser‐assisted sub‐epithelial keratomileusis (LASEK)

A 61‐year‐old Caucasian woman with hyperopia presented for laser refractive surgery. She had healthy eyes with the exception of a less than 0.5 mm Salzmann's nodule at 5 o'clock near the limbus of the right eye. She underwent bilateral hyperopic laser‐assisted sub‐epithelial keratomileusis (LASEK) combined with removal of the Salzmann's nodule. At six months, she was emmetropic with unaided vision of 6/6; however, at 10 months, she noticed a reduction of acuity in her right eye and was found to have a pterygium at 5 o'clock, encroaching 3.5 mm onto the corneal surface. She underwent excision biopsy, local application of mitomycin‐C (0.2 mg/ml for two minutes) and conjunctival auto‐grafting. Following surgery for the pterygium, vision returned to 6/6 unaided but six months later, there was limited recurrence (1.5 mm) of the pterygium reducing unaided vision to 6/9, due to the induction of astigmatism of ‐1.25 dioptres. This has remained stable for 14 months. Pterygium growth may be associated with surface excimer laser surgery and the presence of peripheral Salzmann's nodules might be a risk factor.