Placement of pedicle screws in the thoracic spine. Part II

Vaccaro, Alexander R.; Rizzolo, Steven J.; Balderston, Richard A.; Allardyce, Thomas J.; Garfin, Steven R.; Dolinskas, Carol A.; An, Howard S.

doi:10.2106/00004623-199508000-00009

Cited by 439 publications

(266 citation statements)

References 12 publications

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“…The early anatomic studies by Saillant [144] first established that the diameter and structure of the pedicle is large enough in the lumbar and lower thoracic spine to allow anchorage of vertebral screws via the transpedicular route. These results were later confirmed by other researchers, and there is now convincing evidence regarding pedicle morphology to verify this view [67,82,88,116,129,149,176,193].…”

Section: Rationales For Pedicle Screw Fixationsupporting

confidence: 74%

“…Pedicular screw fixation allows for a transmission of the derotation force to the center of the vertebra and permits a true segmental scoliosis correction [1,92]. Due to the decreasing pedicle diameter in the upper thoracic spine [176], pedicle screws are combined with hooks or, as a further development, pedicle hooks with screw fixation [7]. A disturbing complication of Harrington instrumentation was the development of a flatback syndrome due to the reduction in thoracic kyphosis and lumbar lordosis by distraction [89,125].…”

Section: Scoliosismentioning

confidence: 99%

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Pedicle screw fixation in spinal disorders: A European view

1997

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Continuing controversy over the use of pedicular fixation in the United States is promoted by the lack of governmental approval for the marketing of these devices due to safety and efficacy concerns. These implants have meanwhile become an invaluable part of spinal instrumentation in Europe. With regard to the North American view, there is a lack of comprehensive reviews that consider the historical evolution of pedicle screw systems, the rationales for their application, and the clinical outcome from a European perspective. This literature review suggests that pedicular fixation is a relatively safe procedure and is not associated with a significantly higher complication risk than non-pedicular instrumentation. Pedicle screw fixation provides short, rigid segmental stabilization that allows preservation of motion segments and stabilization of the spine in the absence of intact posterior elements, which is not possible with non-pedicular instrumentation. Fusion rates and clinical outcome in the treatment of thoracolumbar fractures appear to be superior to that achieved using other forms of treatment. For the correction of spinal deformity (i.e., scoliosis, kyphosis, spondylolisthesis, tumor), pedicular fixation provides the theoretical benefit of rigid segmental fixation and of facilitated deformity correction by a posterior approach, but the clinical relevance so far remains unknown. In low-back pain disorders, a literature analysis of 5,600 cases of lumbar fusion with different techniques reveals a trend that pedicle screw fixation enhances the fusion rate but not clinical outcome. The most striking finding in the literature is the large range in the radiological and clinical results. For every single fusion technique poor and excellent results have been described. This review argues that European spine surgeons should begin to back up the evident benefits of pedicle screw systems for specific spinal disorders by controlled prospective clinical trials. This may prevent forthcoming medical licensing authorities from restricting the use of pedicle screw devices and dictating the practice of spinal surgery in Europe in the near future.

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Section: Rationales For Pedicle Screw Fixationsupporting

confidence: 74%

Section: Scoliosismentioning

confidence: 99%

Pedicle screw fixation in spinal disorders: A European view

1997

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“…In our present study, we found an overall accuracy of 73% within the pedicle and a safety of 93% within the safe zone. Vaccaro et al [42] demonstrated a 23% medial cortical perforation with a mean spinal canal compromise of 5 mm in a cadaveric study without the use of fluoroscopy. The percentages of screw misplacement between the various levels in the thoracic spine also did not vary much as expected.…”

Section: Discussionmentioning

confidence: 98%

“…Pedicle screw fixation in such patients is difficult, so accurate and safe placement is mandatory to achieve the fixation [33]. The close proximity of the spinal cord and major soft tissue structures including the aorta, esophagus and lung adds a great risk to the procedure [9,42]. The narrow and inconsistent shape of the thoracic pedicles makes the placement of pedicle screws technically challenging.…”

Section: Introductionmentioning

confidence: 99%

Accuracy and safety of pedicle screw placement in neuromuscular scoliosis with free-hand technique

et al. 2008

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It is a retrospective analytic study of 1,009 transpedicular screws (689 thoracic and 320 lumbosacral), inserted with free-hand technique in neuromuscular scoliosis using postoperative CT scan. The aim of paper was to determine the accuracy and safety of transpedicular screw placement with free-hand technique in neuromuscular scoliosis and to compare the accuracy at different levels in such population. All studies regarding accuracy and safety of pedicle screw in scoliosis represent idiopathic scoliosis using various techniques such as free-hand, navigation, image intensifier, etc., for screw insertion. Anatomies of vertebrae and pedicle are distorted in scoliosis, hence accurate and safe placement of pedicle screw is prerequisite for surgery. Between 2004 and 2006, 37 consecutive patients, average age 20 years (9-44 years), of neuromuscular scoliosis were operated with posterior pedicle screw fixation using free-hand technique. Accuracy of pedicle screws was studied on postoperative CT scan. Placement up to 2 mm medial side and 4 mm lateral side was considered within-safe zone. Of the 1,009 screws, 273 screws were displaced medially, laterally or on the anterior side showing that 73% screws (68% in thoracic and 82.5% in lumbar spine) were accurately placed within pedicle. Considering the safe zone, 93.3% (942/1009, 92.4% in thoracic and 95.3% in lumbar spine) of the screws were within the safe zone. Comparing accuracy according to severity of curve, accuracy was 75% in group 1 (curve \90°) and 69% in group 2 (curve [90°) with a safety of 94.8 and 91.2%, respectively (P = 0.35). Comparing the accuracy at different thoracic levels, it showed 67, 64 and 72% accuracy in upper, middle and lower thoracic levels with safety of 96.6, 89.2 and 93.1%, respectively, exhibiting no statistical significant difference (P = 0.17). Pedicle screw placement in neuromuscular scoliosis with free-hand technique is accurate and safe as other conditions.

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“…Despite earlier concerns regarding the safety of thoracic pedicle screws insertion, introduction of newer techniques has lowered pedicle perforation rates [2,15]. However, there is great variability when comparing the morphometric parameters of the thoracic pedicle in the Western population to those in the Asian population as proven in previous anatomical studies [12,17,18,20,25]. Therefore, the feasibility of thoracic pedicle screw insertion in Asians has not been fully elucidated yet.…”

Section: Introductionmentioning

confidence: 99%

Safety of thoracic pedicle screw application using the funnel technique in Asians: a cadaveric evaluation

2009

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The objective of this cadaveric study is to determine the safety and outcome of thoracic pedicle screw placement in Asians using the funnel technique. Pedicle screws have superior biomechanical as well as clinical data when compared to other methods of instrumentation. However, misplacement in the thoracic spine can result in major neurological implications. There is great variability of the thoracic pedicle morphometry between the Western and the Asian population. The feasibility of thoracic pedicle screw insertion in Asians has not been fully elucidated yet. A pre-insertion radiograph was performed and surgeons were blinded to the morphometry of the thoracic pedicles. 240 pedicle screws were inserted in ten Asian cadavers from T1 to T12 using the funnel technique. 5.0 mm screws were used from T1 to T6 while 6.0 mm screws were used from T7 to T12. Perforations were detected by direct visualization via a wide laminectomy. The narrowest pedicles are found between T3 and T6. T5 pedicle width is smallest measuring 4.1 ± 1.3 mm. There were 24 (10.0%) Grade 1 perforations and only 1 (0.4%) Grade 2 perforation. Grade 2 or worse perforation is considered significant perforation which would threaten the neural structures. There were twice as many lateral and inferior perforations compared to medial perforations. 48.0% of the perforations occurred at T1, T2 and T3 pedicles. Pedicle fracture occurred in 10.4% of pedicles. Intra-operatively, the absence of funnel was found in 24.5% of pedicles. In conclusion, thoracic pedicle screws using 5.0 mm at T1-T6 and 6.0 mm at T7-T12 can be inserted safely in Asian cadavers using the funnel technique despite having smaller thoracic pedicle morphometry.

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Placement of pedicle screws in the thoracic spine. Part II

Cited by 439 publications

References 12 publications

Pedicle screw fixation in spinal disorders: A European view

Pedicle screw fixation in spinal disorders: A European view

Accuracy and safety of pedicle screw placement in neuromuscular scoliosis with free-hand technique

Safety of thoracic pedicle screw application using the funnel technique in Asians: a cadaveric evaluation

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