Gereç ve Yöntem: 62 hasta için kullanılan 450 poliaksiyel vida değerlendirildi. Tüm vidalar bir eğitim hastanesinde serbest el tekniğiyle yerleştirildi. Vidaların isabetleri Zdichavsky skorlama sistemi ile derecelendirildi.

Bulgular: 450 vidanın 397’si (%88.21) 1a (en iyi pozisyon) ve 1b (iyi pozisyon) olarak derecelendirildi. 8 kötü pozisyondaki vida hariç 450 vidanın 442’si (%98.22) kabul edilebilir pozisyondaydı.

Sonuç: Pedikül vidası yerleştirme tekniğinden bağımsız olarak, cerrahinin başarısını cerrahın yeteneği ve deneyimi belirler. Unstabil torakolumbar kırıklar için serbest elle vida yerleştirmek güvenilir bir tekniktir ve hem cerrahı hem de hastayı aşırı radyasyon maruziyetinden korur.

The aim of this study is to evaluate if the pedicle screw placement with free-hand technique for thoracolumbar fructures is a safe technique or not, by evaluating screw accuracy and complication rate.

Surgical Technique: All the patients are positioned prone and then the fracture level was determined with C-arm. Midline longitudinal incision was used. The facet joint and the transverse process were exposed. Anatomic land marks were used to determine the starting point for screw placement. Determined points for all levels were perforated with an awl. Marker pins were inserted at these starting points and checked if they were proper with an AP C-arm view. Then a pedicle finder was inserted through the pedicle with a proper orientation according to the level of the spine. Trajectory was checked with a pedicle probe for cortical wall violation and the length of the screw was determined also with the probe. All the pedicle screws were placed and then checked with AP and lateral C-arm views. For short segment fixation only three C-arm views were used for the entire operation.

Radiological evaluation: Axial CT scan views passing through the middle of the pedicle screws were used for radiological evaluation. All accuracy evaluations were performed by one senior surgeon according to the Zdichavsky grading system ^3,4 (Figure 1). All the percentage calculations were done with Microsoft Office Excel program (2007).

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Table 1: Pedicle screw distribution over thoracolumbar spine

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Table 2: Grading of the screws according to Zdichavsky grading system for each level

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Figure 1: Zdichavsky grading system and radiological evaluation

Parker et al. ⁸ reported accuracy of 6817 pedicle screws placed with free-hand technique in the thoracolumbar spine. It was reported that there are only 117 (1.7%) malpositioned screws and as expected most of them are in the thoracic levels. Only 0.8% required revision surgery.

Nevzati et al. ⁹ reported a series of o education center where the residents and trainees placed screws under the control of a supervising surgeon. 1236 screws of 273 patients was analyzed with Gertzbein classification ¹⁰. The ratio of malpositioned screws was 20 % and similar to previous studies malposition of the screws are significantly high in thoracic levels.

Meta-analysis of 85 studies comparing free-hand, fluoroscopy guidance and navigation techniques was reported by Gelali et al. ². These studies contain total 1105 patients including 6617 screws. This meta-analysis indicates that navigation, especially CT navigation, has higher accuracy than free-hand technique and fluoroscopy guidance. According to this review screws placed with free-hand technique tend to perforate the medial cortex, where as the screws placed with CT navigation guidance seem to perforate more often laterally. This study noted the same situation for free-hand technique. However, CT navigation has higher accuracy, it is reported that there was no significant difference between the technique used and the complication rate.

Most of the studies about this subject reports, also as indicated in this studies result, pedicle screw placement for thoracic spine is more demanding. More recent meta-analysis compared CT navigation and fluoroscopy-guided navigation for thoracic pedicle screw placement ¹¹. Two techniques were compared for accuracy, incidence of complications, time of insertion, blood loss and operative time. It was indicated that CT navigation is better on mentioned subjects than fluoroscopy except operative time. Authors conclude that despite all its’ benefits high cost of devices and very high radiation exposure of patient and surgeons limits the use of CT navigation.

Most of the studies about this subject contains heterogenous patient population. Results were obtained from both trauma, deformity and fusion cases. This study was designed to evaluate only for trauma patients to homogenize the population. Verma et al. ¹² also studied on trauma cases. It was reported that better accuracy of navigation systems did not improve the functional outcomes and reduce neurologic complications of trauma patients.

Warner et al. ¹³ examined the clinical effects of improved pedicle screw accuracy with computer navigation technology in reducing complication rates in 3168 patients undergoing multi-level spinal fusion. It was indicated that surgical time was significantly longer in the navigation group (391.41 versus 350.3 minutes), but there were no significant improvements in complication rates.

Main limitations of this study is relatively small population and the grading system that was used to evaluate the accuracy. Zdichavsky ⁴ grading system evaluates the screw position only at axial orientation. Despite the limitations our results are similar to such reports. It is also a limitation that there is no long-term functional outcome results because aim of this study is to determine the accuracy of free-hand technique and early postoperative complication rates based on malpositioned pedicle screws.

Conclusion; in the recent decades pedicle screws became gold standard for stabilization of the thoracolumbar fractures. Especially for thoracic spine pedicle screw placement is a demanding procedure. However complication rate associated with pedicle screw malposition is quite low. Large series have reported high levels of accuracy for a variety of techniques including free-hand technique, 2D non-guided fluoroscopy, and with various types of intraoperative guidance. Despite better accuracy rates of CT navigation, it is not superior to conventional methods about functional outcomes and complication rates. Regardless of the pedicle screw placement technique the skill and experience of the surgeon designates the success of the surgery. For unstable traumatic thoracolumbar fractures pedicle screw placement with free-hand is a safe technique and avoids excessive radiation exposure both for surgeon and patient.

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