Abstract Objective Compare by mechanical tests the pullout resistance and the insertion torque of rough and smooth pedicle screws. Methods Pedicle screws with rough surface and smooth surface, with diameters of 4.8; 5.5 and 6.5 mm, were inserted in polyurethane blocks with density of 10 PCF (0.16 g/cm3). Insertion torque and pullout strength were assessed. Results The pullout strength of the rough surface and smooth surface screws did not differ, except in the group of 4.8 mm diameter screws. In this group, the rough surface screws showed greater resistance to pullout. Conclusion Pedicle screws with a rough surface did not show increased pullout resistance in the acute phase of their insertion in polyurethane blocks compared to smooth surface screws. The rough surface screws had a higher insertion torque than the smooth surface screws, depending on the diameter of the screw and the preparation of the pilot hole.

ABSTRACT Objectives To observe the influence of the congruence of the tapping of the pilot hole on the anchorage of the pedicle screws. Methods 5.5 and 6.5 mm screws from two vertebral fixation systems (Pedicol and Safe) were inserted into polyurethane blocks. Experimental groups were formed according to the pilot hole preparation: A- drilling with a 2.7 mm drill bit, B- Tapping of the pilot hole with a tap of lesser diameter than the diameter of the screw with a congruent thread design, C- Tapping of the pilot hole with a tap of lesser diameter than the diameter of the screw and an incongruous thread design. The polyurethane blocks with the screws were subjected to a tensile strength test to evaluate the pullout resistance of the screws. Results Using congruent pilot hole tapping of a lesser diameter and congruent thread design increased the pullout resistance of the rough-surface screws (Safe). The screws with a smooth surface (Pedicol) presented greater pullout resistance with tapping of a lesser diameter and incongruous thread design. Conclusions The congruence of the tap used to prepare the pilot hole increased the pullout resistance of the rough-surfaced screws. Level of Evidence III; Therapeutic Study.

ABSTRACT Objective: To evaluate the morphological changes on the intervertebral foramen and segmental lordosis related to the transforaminal lumbar interbody fusion (TLIF) positioning. Methods: PEEK cages were placed in the disc space (L1-S1) of a polyurethane anatomical model. Cages of different heights (8 mm, 10 mm, 12 mm and 14 mm) were positioned in the posterior, medial or anterior part of the vertebral body surface, and the intervertebral foramen and segmental lordosis heights were measured after their insertion. Results: The vertebral foramen height decreased in all positions and heights of the cages in relation to the control. The cage posterior positioning induced a smaller reduction in the vertebral foramen height. Vertebral lordosis tended to increase in relation to the control, and the greatest increase occurred with the cage posterior positioning. Conclusion: Cage positioning induces changes in the intervertebral foramen height and in the vertebral segment lordosis. Cage posterior positioning induces a smaller reduction of the intervertebral foramen height and increases the vertebral segment lordosis. Level of evidence III, Therapeutic study.

Abstract Objective The present study aimed to develop and evaluate the use of customized guides in patients undergoing surgery to correct vertebral deformity with a pedicular fixation system. Methods Four patients with spinal deformity (three with idiopathic scoliosis and one with congenital kyphoscoliosis) underwent surgical treatment to correct the deformity with a pedicular fixation system. Prototypes of 3D cost guides were developed and evaluated using technical feasibility, accuracy, and radiation exposure. Results The present study included 85 vertebral pedicles in which pedicle screws were inserted into the thoracic spine (65.8%) and into the lumbar spine (34.2%). Technical viability was positive in 46 vertebral pedicles (54.1%), with 25 thoracic (54%) and 21 lumbar (46%). Technical viability was negative in 39 pedicles (45.9%), 31 of which were thoracic (79.5%), and 8 were lumbar (20.5%). In assessing accuracy, 36 screws were centralized (78.2%), of which 17 were in the thoracic (36.9%) and 19 in the lumbar spine (41.3%). Malposition was observed in 10 screws (21.7%), of which 8 were in the thoracic (17.4%) and 2 in the lumbar spine (4.3%). The average radiation record used in the surgical procedures was of 5.17 ± 0.72 mSv, and the total time of use of fluoroscopy in each surgery ranged from 180.3 to 207.2 seconds. Conclusion The customized guide prototypes allowed the safe preparation of the pilot orifice of the vertebral pedicles in patients with deformities with improved accuracy and reduced intraoperative radiation.

ABSTRACT Objective: Cervical spondylotic myelopathy (CSM) is the main cause of spinal dysfunction in adults. The type of surgical approach to treatment is not well defined in the literature. The objective is to report the results obtained through isolated posterior decompression in patients with a previous indication of the combined approach for the treatment of cervical spondylotic myelopathy. Methods: This is a therapeutic study with level of evidence II, according to the Oxford classification table. Ten patients who underwent isolated posterior approach surgery for the treatment of cervical spondylotic myelopathy were evaluated through imaging and questionnaires (visual analog scale, mJOA-Br scale – Brazilian Portuguese version of the Modified Japanese Orthopedic Association Scale, and Neck Disability Index (NDI)), comparing pre- and postoperative results. Results: Late evaluation of the 10 patients was performed in the period ranging from 24 to 36 months (mean of 30.3 months ± 7.25) following surgery. The comparison of the clinical and radiological parameters in all patients showed a statistical difference in relation to the preoperative scales applied and to the degree of cervical lordosis (p <0.05), evidencing improvement after decompression and posterior fixation of the cervical spine. Conclusions: The isolated posterior approach (decompression, fixation and arthrodesis) allowed the clinical and radiological improvement of patients with cervical spondylotic myelopathy and who had an indication of the complementary anterior approach. Level of evidence II; Retrospective study.

Abstract Gout is a crystalline arthropathy frequent in the population, but gouty spondyloarthropathy, also called axial gout, is uncommon. The current case report presents a rare case of cervical myelopathy secondary to axial gout. A 50-year-old female patient, without previous pathologies, presented with loss of strength, altered sensitivity, and pyramidal release for 2 years. The computed tomography showed a lytic image in the spinous process of C7, and signs of myelopathy with myelomalacia on magnetic resonance imaging of the cervical spine. After the surgical procedure and biopsy of the material, the diagnosis was gout, and treatment for the pathology was started, with complete improvement of the condition. The diagnosis of axial gout should be included in the spectrum of the differential diagnosis of diseases that affect the spine. Although gouty spondyloarthritis (or spondylitis) is uncommon, there is an underestimated occurrence due to the lack of investigation of the cases. The early diagnosis and treatment of the pathology can prevent patients from presenting complications of the disease, as reported in the present study.