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Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma
G Model OTSR-972; No. of Pages 5
ARTICLE IN PRESS Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx
Available online at
ScienceDirect www.sciencedirect.com
Original article
Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma M. Tinelli a , S. Matschke a , M. Adams a , P.A. Grützner a , M. Münzberg a , A.J. Suda a,∗,b a Department for Trauma and Orthopaedic Surgery, BG Trauma Center Ludwigshafen, Heidelberg University Hospital, Ludwig Guttmann Strasse 13, 67071 Ludwigshafen, Germany b Department for Septic Surgery, BG Trauma Center Ludwigshafen, Germany
a r t i c l e
i n f o
Article history: Accepted 6 March 2014 Keywords: Spine ORIF Minimally invasive spine fixation Navigation Pedicle screws
a b s t r a c t Background: When performing minimally invasive spine surgery in trauma patients, a short operation time and a perfect positioning of pedicle screws are demanded. In this study, we show that a Minimally Invasive Pedicle Screw System allows both. Methods: One hundred and twenty-one patients (131 fractures) with fractures between Th 3 and L 5 were treated. The most common fracture type was A3. We treated 52 females and 69 men with a mean age of 56.7 years. In 72% of the cases, the procedure was performed by two experienced spine surgeons. Postoperatively, all patients were examined using a CT-scan. In 61 patients, an anterior stabilization was additionally performed in 33 patients, vertebroplasty or cyphoplasty was performed. Fifteen patients underwent laminectomy. Results: No patient postoperatively developed any additional neurological compromise. In total, 682 screws were placed. In the postoperative CT-scan, we found 16 screws (2.2%) in suboptimal position, 8 with medial and 8 with lateral deviation. Discussion: With the Minimally Invasive Pedicle Screw System used in this study, spinal fractures can be treated in a short operation time with percutaneous stabilization and a correct positioning of the pedicle screws in almost 98%. In our study, no screw was so much malpositioned that revision surgery would have been necessary. Level of evidence: Level III – Case-control study. © 2014 Elsevier Masson SAS. All rights reserved.
1. Background Access morbidity has been demonstrably reduced since the introduction of implants for ventral fusion and new minimal invasive surgical techniques in spine surgery with the aid of video-assisted endoscopic approaches and mini-open-techniques in lumbar spine fractures [1,2]. The advantages of dorsal percutaneous pedicle screw insertion for the patient are the chances of early mobilization and reduction of postoperative pain (Fig. 1). Despite the reduced access, morbidity in ventral approaches remains a dorsal muscle injury after dorso-ventral instrumentation of spine instabilities due to the need to remove the multifidus muscle during screw placement. The postoperative function of the multifidus muscle is determined by time of use of a retraction system during surgery [3,4]. A proven method to quantitatively
∗ Corresponding author. Tel.: +49 621 68100; fax: +49 621 6810 2685. E-mail addresses: [email protected], [email protected] (A.J. Suda).
determine the extent of muscle injury is measuring the creatine kinase level [5]. In 2008, Lehmann et al. showed a significantly lower release of creatine kinase after percutaneous screw insertion compared to open insertion in a sheep model [6]. Even in electrophysiological studies, the damage to the long back muscles and the autochtone back muscles using the open approach compared to the minimal invasive approach is evident [7]. Dependent on the surgeon’s experience, blood losses of 500 to 1200 mL are common when the open approach is used [7]. In major orthopaedic spine surgery, blood loss of more than 2000 mL is possible which is a risk factor for infection [8,9]. The blood loss can be considerably reduced if minimal invasive techniques are used [10]. Dependent on the surgeon’s experience in closed fracture reduction, the percutaneous minimal invasive procedure ranges from injuries type A3/AO through B to C1/AO but can have limitations. Luxation injuries and long-distance rotational injuries are difficult to repose in the closed technique and may require open reduction and screw insertion. The reconstruction of the physiological sagittal spine profile remains one of the goals in treatment of traumatic vertebral
http://dx.doi.org/10.1016/j.otsr.2014.03.015 1877-0568/© 2014 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
G Model OTSR-972; No. of Pages 5
ARTICLE IN PRESS M. Tinelli et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx
2
Fig. 2. Percutaneous positioning of the Yamshidi needles.
3. Results Fig. 1. Small incisions after percutaneous pedicle screw insertion.
fractures. This must not be abandoned in view of the advantages of the minimal invasive technique [11]. The array of indications for percutaneous thoraco-lumbal instrumentation could be widened if a sufficiently active reduction maneuver can be performed when positioning the patient on the operation table, which is contrary to what Blattert et al. state [12]. In osteoporotic fractures, attention must be paid to reduction maneuvers as mentioned above. A reposition with bended rods could lead to screw dislocation while fixing the setscrew. In highly unstable injuries, the primary stability and an early functional aftercare should be the primary treatment objective. We hypothesize that a percutaneous minimal invasive dorsal stabilization system allows short operating times with correct screw positioning. 2. Methods In 121 consecutive patients with 131 fractures of a thoracic and/or lumbar vertebra, we performed a dorsal stabilization with the Minimally Invasive Polyaxial Pedicle Screw System VIPER® 2 (De Puy, Warsaw, IL) between May 2009 and March 2011 at BG Trauma Centre Ludwigshafen, Germany (Figs. 2 and 3). The most common fracture type was A3 (A3.1: 23×, A3.2: 29×, A3.3: 32×) but also type B (B1: 5×, B2: 7×, B3: 1×) and one type C2. We treated 121 patients (52 women/43% and 69 men/57%) with 131 fractures and the mean age at time of operation was 56.7 years (range 10 to 88). In 72% of cases (88 patients), the procedure was performed by two experienced spine surgeons. Experienced trauma surgeons performed all other cases. The surgery was performed in the prone position and general anaesthesia and the patient’s positioning were realized by the surgeon. Intraoperatively, fluoroscopy was used for screw positioning. Additional blood was only used for patients with multiple injuries who underwent spine surgery and another major orthopaedic trauma surgery at the same time. Patients who received single stabilization of the spine did not receive any blood products. After the surgery, the neurological state of the patient was evaluated immediately by the surgeon and on the following day, all patients were examined using a CT-scan with 1 mm layer and the screw positions were checked and evaluated. A malposition was defined as a screw not exactly in or perforating the pedicle by more than 2 mm according to Gertzbein [13].
A total of 682 screws were placed in 121 patients. In 33 patients, vertebroplasty was also performed and 61 patients required ventral stabilization which was performed during the same operation in 15 patients and within one week after the first procedure for the other patients (51 × cages, 10 × locking plates with iliac crest bone graft). Fifteen patients required laminectomy. The procedures were performed by 11 experienced trauma surgeons but 71.9% of cases (88 patients) were performed by two experienced spine surgeons. No significant difference in operation duration was found between the surgeons (P > 0.05). No additional nerve injury occurred after surgery; one in five patients showed complete remission of neurological disability after the procedure despite immediate laminectomy after the percutaneous procedure in all patients with neurological disability. In the CT-scan, 16 screws (2.2%) were malpositioned, 8 medially and 8 laterally but no screw perforated the pedicle by more than 5 mm. (Fig. 4) (Table 1) No revision was performed because of the screw position, all screws were
Fig. 3. Percutaneous screw insertion with small incisions.
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
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Table 1 Results of CT-scan after positioning of the screws by surgeons. Age
AO-fracture classification
Fracture height
Trauma surgeon/very experienced spine surgeon
Number of screws
Postoperative CT-scan
17 22 23 26 34 40 45 45 46 46 48 50 51 53 53 55 58 59 59 60 64 67 68 75 75 76 79 80 81 81 88 19 28 43 57 59 59 62 64 64 65 66 68 69 73 75 78 85 45 10 19 41 47 59 50 71 74 76 80 55
A3 A3 A3 A3 A3 A3 A3 A3 A3 B1 A3 A2 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A1 A3 B2 A3 A3 A3 A3 A3 A3 A3 A1 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 B2 B2 A2, A3
L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2, (L1, L3) L3 L3 L3 L3 L3 L4 L4 L4 L4 L4 L4, 5
TS TS TS VESS VESS VESS VESS TS VESS VESS TS VESS VESS VESS VESS VESS VESS VESS TS VESS VESS TS VESS VESS VESS TS TS VESS VESS VESS VESS VESS VESS TS TS VESS VESS TS TS VESS VESS VESS VESS VESS VESS VESS VESS VESS TS VESS VESS VESS TS VESS VESS TS TS VESS VESS VESS
4 6 4 8 4 4 4 6 6 4 4 4 4 4 4 4 4 4 4 6 6 8 8 4 8 6 6 4 6 4 5 4 4 4 4 6 8 4 6 6 4 4 4 8 4 8 4 4 6 6 4 4 4 4 4 4 4 6 7 8
49 57 20 71 21 76 44 48 59 62 70 72 83
A3 A3 A3 A3 A3 A3 2xA3 A3 A3 A3 A3 B A3
L5 L5 Th 5 Th 5, 7, 9 Th 5/6 Th 8/9 Th10, 11 Th11 Th11 Th11 Th11 Th11 Th11
TS VESS TS VESS VESS VESS VESS VESS VESS VESS VESS VESS VESS
6 4 4 4 8 4 8 4 4 4 8 8 4
Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits L3 right screw 1,2 mm medial Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits L5 left screw 1 mm medial Within normal limits Within normal limits S1 left screw medial intraarticular L5/S1 Within normal limits Within normal limits Th4 right screw 4 mm medial Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
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4 Table 1 (Continued) Age
AO-fracture classification
Fracture height
Trauma surgeon/very experienced spine surgeon
Number of screws
Postoperative CT-scan
72 27
A3 B
Th11, 12, L1 Th11/12
VESS TS
8 4
63 22 26 30 40 45 45 48 48 48 53 61 70 74 76 76 76 82 50 48 47 72 75 83 22 45 61
A3 A3 A3 C2 A3 A3 A3 A3 A3 A3 A3 A3 A1 A3 A3 A3 A3 A3 A3 A3 B A1, A3 B A3 A2 A3 B
Th11/12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12, L2 Th3 Th3 Th3/4 Th4 Th4, 5 Th5 Th5 Th5, 6
VESS TS VESS VESS VESS VESS VESS VESS VESS VESS TS TS TS VESS VESS VESS VESS TS TS TS VESS VESS VESS VESS VESS TS VESS
6 4 4 6 4 4 4 4 4 4 6 4 6 6 8 4 4 8 6 8 6 5 9 8 8 8 8
27 67 71 79 72 82 77 53 71 87 69
B2 A1, A3 A3 A3 A3 A3 2 × A3, 2xA2 A3 A3 A3 A2, B3
Th5, 6, 7 Th5/6, Th12, Th6 Th6 Th6 Th6, 7; L1 Th6-9 Th7 Th7 Th7 Th7, Th12
VESS VESS VESS TS VESS VESS VESS TS VESS VESS TS
8 8 6 4 6 8 11 4 8 6 8
44 35 36 73 77 18 50 73
A3 A3 A3 A3 A3 2xA3 B1 B1
Th7, 12 Th8 Th8 Th8 Th8 Th9, 10 Th9, 10 Th9, 10
VESS VESS TS VESS VESS TS TS VESS
8 8 8 4 6 8 8 8
Th12 right screw 1 mm lateral Th 11 right screw 3,2 mm medial Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Th11 left screw 4,3 mm lateral Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Th2 right screw 1 mm lateral Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Th4 and 6 left screws 1,5 mm lateral Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Th6 right screw 1 mm lateral Within normal limits Th8 left screw 1 mm medial Th11 right screw 2,2 mm lateral Th6 right screw 1 mm lateral Th6 left screw 2,6 mm medial Within normal limits Within normal limits Th7 right screw 2,7 mm medial Within normal limits Within normal limits Within normal limits
stated as acceptable and no new neurological symptoms occurred. One patient had revision surgery because of local subcutaneous haematoma but without any changing of the implants. The mean duration of the operation was 81 minutes (range 19 to 282) and the mean radiation time was 126 seconds (range 9 to 740) in all patients and for all surgeons including the procedures in multiple injured patients who received spinal stabilization and additional trauma procedures. The mean duration of the operation was 65 minutes (range 35 to 109) in patients with two-level stabilization and four screws. The two experienced surgeons, who performed almost 72% of the operations, had a mean procedure duration of 36 minutes (range 19 to 46) and a mean radiation time of 59.9 seconds (range 20 to 200) for bi-segmental stabilization. 4. Discussion In this study, percutaneous minimal invasive dorsal instrumentation offers correct screw positioning with short operation and radiation times, which was our hypothesis. This procedure is
appropriate for dorsal instrumentation without the need of dorsal fusion. The combination with decompression and laminectomy is possible in any vertebral height. In view of the minimal soft tissue trauma and the minimal blood loss compared to the open technique, it can be recommended for every patient with an urgent indication for surgical spinal stabilization [14]. Dependent of the used implant, multi-segmental percutaneous dorsal instrumentations may not necessarily require long operation times. The disadvantage of this technique is the surgeon’s and operating theatre’s staff’s learning curve but with increasing experience, the array of indications increases from simple type A fractures to distraction-rotation-injuries. A limitation of the technique is the luxation injury and some highly unstable rotational injuries. Beck et al. mentioned the advantage and the exact evaluation of the screw position using intraoperative 3D-visualization [15]. In our study, the rate of malpositioned screws is comparable to those using a navigation system in the literature [16–18]. Perforation of the pedicle is possible because of the individual pedicle thickness, which can be smaller than the screw diameter.
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
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References
Fig. 4. Postoperative CT-scan with too medial positioning of the screws without new neurological symptoms and without indication for revision.
Some studies show an advantage with screw positioning using robotic techniques because of reduced malpositioning and with that a reduced radiation time and shorter operation time [19,20]. Anand et al. reported an intraoperative blood loss of 260 mL in a series of minimal invasive percutaneous multilevel corrections in degenerative lumbar scoliosis compared to up to 3000 mL using the open technique [21,22]. Blood loss is determined by the technique and comorbidities like septic diseases in spondylodiscitis, patients with malignant diseases or patients with multiple injuries. These patients benefit from a percutaneous minimal invasive procedure regarding the estimated blood loss, if a dorsal instrumentation is required. In this study, the mean operation time for percutaneous bi-segmental dorsal minimal invasive stabilization by an experienced surgeon was 36 minutes with a mean radiation time of 103 seconds. Using other implants with comparable operation times, mean radiation times can exceed 200 seconds [23,24]. 5. Conclusion With this study, the accuracy of percutaneous pedicle screw placement in minimal invasive spine trauma surgery was evident. With short operation times, minimal blood loss, 97.8% of correct screw position and no revision because of malpositioning, this method was absolutely appropriate for the patients in this study. Better accuracy of pedicle screw positioning is no argument for open trauma spine surgery. Disclosure of interest The authors declare that they have no conflict of interest.
[1] Beisse R, Potulski M, Bühren V. Endoscopic techniques for the management of spinal trauma. Eur J Trauma 2001;27:275–91. [2] Rodriguez-Vela J, Lobo-Escolar A, Joven-Aliaga E, Herrera A, Vicente J, Sunen E, et al. Perioperative and short-term advantages of mini-open approach for lumbar spinal fusion. Eur Spine J 2009;18:1194–201. [3] Gejo R, Matsui H, Kawaguchi Y, Ishihara H, Tsuji H. Serial changes in trunk muscle performance after posterior lumbar surgery. Spine 1999;24: 1023–8. [4] Kim DY, Lee SH, Chung SK, Lee HY. Comparison of multifidus muscle atrophy and trunk extension muscle strength: percutaneous versus open pedicle screw fixation. Spine 2005;30:123–9. [5] Kumbhare D, Parkinson W, Dunlop B. Validity of serum creatine kinase as a measure of muscle injury produced by lumbar surgery. J Spinal Disord Tech 2008;21(1):49–54. [6] Lehmann W, Ushmaev A, Ruecker A, Nuechtern J, Grossterlinden L, Begemann PG, et al. Comparison of open versus percutaneous pedicle screw insertion in a sheep model. Eur Spine J 2008;17:857–63. [7] Grass R, Biewener A, Dickopf A, Rammelt S, Heineck J, Zwipp H. [Percutaneous dorsal versus open instrumentation for fractures of the thoracolumbar border. A comparative, prospective study]. Unfallchirurg 2006;109: 297–305. [8] Samama CM, Langeron O, Rosencher N, Capdevila X, Rouche P, Pegoix M, et al. Aprotinin versus placebo in major orthopedic surgery: a randomized, doubleblinded, dose-ranging study. Anesth Analg 2002;95:287–93. [9] Koutsoumbelis S, Hughes AP, Girardi FP, Cammisa Jr FP, Finerty EA, Nguyen JT, et al. Risk factors for postoperative infection following posterior lumbar instrumented arthrodesis. J Bone Joint Surg Am 2011;93: 1627–33. [10] Schoenfeld AJ, Ochoa LM, Bader JO, Belmont Jr PJ. Risk factors for immediate postoperative complications and mortality following spine surgery: a study of 3475 patients from the National surgical quality improvement program. J Bone Joint Surg Am 2011;93:1577–82. [11] Verheyden AP. Thoracolumbar spine. Unfallchirurg 2011;114:8. [12] Blattert TR, Katscher S, Josten C. Percutaneous techniques in the thoracic and lumbar spine. Unfallchirurg 2011;114:17–25. [13] Gertzbein SD, Robbins SE. Accuracy of pedicular screw placement in vivo. Spine (Phila Pa 1976) 1990;15:11–4. [14] Hu SS. Blood loss in adult spinal surgery. Eur Spine J 2004;13(Suppl. 1):S3–5. [15] Beck M, Mittlmeier T, Gierer P, Harms C, Gradl G. Benefit and accuracy of intraoperative 3D-imaging after pedicle screw placement: a prospective study in stabilizing thoracolumbar fractures. Eur Spine J 2009;18:1469–77. [16] Kosmopoulos V, Schizas C. Pedicle screw placement accuracy: a meta-analysis. Spine 2007;32:E111–20. [17] Papadopoulos EC, Girardi FP, Sama A, Sandhu HS, Cammisa Jr FP. Accuracy of single-time, multilevel registration in image-guided spinal surgery. Spine J 2005;5:263–7. [18] Schwarzenbach O, Berlemann U, Jost B, Visarius H, Arm E, Langlotz F, et al. Accuracy of computer-assisted pedicle screw placement. An in vivo computed tomography analysis. Spine 1997;22:452–8. [19] Kantelhardt SR, Martinez R, Baerwinkel S, Burger R, Giese A, Rohde V. Perioperative course and accuracy of screw positioning in conventional, open robotic-guided and percutaneous robotic-guided, pedicle screw placement. Eur Spine J 2011;20:860–8. [20] Lieberman IH, Hardenbrook MA, Wang JC, Guyer RD. Assessment of pedicle screw placement accuracy, procedure time, and radiation exposure using a miniature robotic guidance system. J Spinal Disord Tech 2012;25: 241–8. [21] Anand N, Baron EM, Thaiyananthan G, Khalsa K, Goldstein TB. Minimally invasive multilevel percutaneous correction and fusion for adult lumbar degenerative scoliosis: a technique and feasibility study. J Spinal Disord Tech 2008;21:459–67. [22] Huang QS, Chi YL, Wang XY, Mao FM, Lin Y, Ni WF, et al. [Comparative percutaneous with open pedicle screw fixation in the treatment of thoracolumbar burst fractures without neurological deficit]. Zhonghua Wai Ke Za Zhi 2008;46:112–4. [23] Prokop A, Lohlein F, Chmielnicki M, Volbracht J. Minimally invasive percutaneous instrumentation for spine fractures. Unfallchirurg 2009;112:621–8. [24] Wang HW, Li CQ, Zhou Y, Zhang ZF, Wang J, Chu TW. Percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system: an analysis of 38 cases. Chin J Traumatol 2010;13:137–45.
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
ARTICLE IN PRESS Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx
Available online at
ScienceDirect www.sciencedirect.com
Original article
Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma M. Tinelli a , S. Matschke a , M. Adams a , P.A. Grützner a , M. Münzberg a , A.J. Suda a,∗,b a Department for Trauma and Orthopaedic Surgery, BG Trauma Center Ludwigshafen, Heidelberg University Hospital, Ludwig Guttmann Strasse 13, 67071 Ludwigshafen, Germany b Department for Septic Surgery, BG Trauma Center Ludwigshafen, Germany
a r t i c l e
i n f o
Article history: Accepted 6 March 2014 Keywords: Spine ORIF Minimally invasive spine fixation Navigation Pedicle screws
a b s t r a c t Background: When performing minimally invasive spine surgery in trauma patients, a short operation time and a perfect positioning of pedicle screws are demanded. In this study, we show that a Minimally Invasive Pedicle Screw System allows both. Methods: One hundred and twenty-one patients (131 fractures) with fractures between Th 3 and L 5 were treated. The most common fracture type was A3. We treated 52 females and 69 men with a mean age of 56.7 years. In 72% of the cases, the procedure was performed by two experienced spine surgeons. Postoperatively, all patients were examined using a CT-scan. In 61 patients, an anterior stabilization was additionally performed in 33 patients, vertebroplasty or cyphoplasty was performed. Fifteen patients underwent laminectomy. Results: No patient postoperatively developed any additional neurological compromise. In total, 682 screws were placed. In the postoperative CT-scan, we found 16 screws (2.2%) in suboptimal position, 8 with medial and 8 with lateral deviation. Discussion: With the Minimally Invasive Pedicle Screw System used in this study, spinal fractures can be treated in a short operation time with percutaneous stabilization and a correct positioning of the pedicle screws in almost 98%. In our study, no screw was so much malpositioned that revision surgery would have been necessary. Level of evidence: Level III – Case-control study. © 2014 Elsevier Masson SAS. All rights reserved.
1. Background Access morbidity has been demonstrably reduced since the introduction of implants for ventral fusion and new minimal invasive surgical techniques in spine surgery with the aid of video-assisted endoscopic approaches and mini-open-techniques in lumbar spine fractures [1,2]. The advantages of dorsal percutaneous pedicle screw insertion for the patient are the chances of early mobilization and reduction of postoperative pain (Fig. 1). Despite the reduced access, morbidity in ventral approaches remains a dorsal muscle injury after dorso-ventral instrumentation of spine instabilities due to the need to remove the multifidus muscle during screw placement. The postoperative function of the multifidus muscle is determined by time of use of a retraction system during surgery [3,4]. A proven method to quantitatively
∗ Corresponding author. Tel.: +49 621 68100; fax: +49 621 6810 2685. E-mail addresses: [email protected], [email protected] (A.J. Suda).
determine the extent of muscle injury is measuring the creatine kinase level [5]. In 2008, Lehmann et al. showed a significantly lower release of creatine kinase after percutaneous screw insertion compared to open insertion in a sheep model [6]. Even in electrophysiological studies, the damage to the long back muscles and the autochtone back muscles using the open approach compared to the minimal invasive approach is evident [7]. Dependent on the surgeon’s experience, blood losses of 500 to 1200 mL are common when the open approach is used [7]. In major orthopaedic spine surgery, blood loss of more than 2000 mL is possible which is a risk factor for infection [8,9]. The blood loss can be considerably reduced if minimal invasive techniques are used [10]. Dependent on the surgeon’s experience in closed fracture reduction, the percutaneous minimal invasive procedure ranges from injuries type A3/AO through B to C1/AO but can have limitations. Luxation injuries and long-distance rotational injuries are difficult to repose in the closed technique and may require open reduction and screw insertion. The reconstruction of the physiological sagittal spine profile remains one of the goals in treatment of traumatic vertebral
http://dx.doi.org/10.1016/j.otsr.2014.03.015 1877-0568/© 2014 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
G Model OTSR-972; No. of Pages 5
ARTICLE IN PRESS M. Tinelli et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx
2
Fig. 2. Percutaneous positioning of the Yamshidi needles.
3. Results Fig. 1. Small incisions after percutaneous pedicle screw insertion.
fractures. This must not be abandoned in view of the advantages of the minimal invasive technique [11]. The array of indications for percutaneous thoraco-lumbal instrumentation could be widened if a sufficiently active reduction maneuver can be performed when positioning the patient on the operation table, which is contrary to what Blattert et al. state [12]. In osteoporotic fractures, attention must be paid to reduction maneuvers as mentioned above. A reposition with bended rods could lead to screw dislocation while fixing the setscrew. In highly unstable injuries, the primary stability and an early functional aftercare should be the primary treatment objective. We hypothesize that a percutaneous minimal invasive dorsal stabilization system allows short operating times with correct screw positioning. 2. Methods In 121 consecutive patients with 131 fractures of a thoracic and/or lumbar vertebra, we performed a dorsal stabilization with the Minimally Invasive Polyaxial Pedicle Screw System VIPER® 2 (De Puy, Warsaw, IL) between May 2009 and March 2011 at BG Trauma Centre Ludwigshafen, Germany (Figs. 2 and 3). The most common fracture type was A3 (A3.1: 23×, A3.2: 29×, A3.3: 32×) but also type B (B1: 5×, B2: 7×, B3: 1×) and one type C2. We treated 121 patients (52 women/43% and 69 men/57%) with 131 fractures and the mean age at time of operation was 56.7 years (range 10 to 88). In 72% of cases (88 patients), the procedure was performed by two experienced spine surgeons. Experienced trauma surgeons performed all other cases. The surgery was performed in the prone position and general anaesthesia and the patient’s positioning were realized by the surgeon. Intraoperatively, fluoroscopy was used for screw positioning. Additional blood was only used for patients with multiple injuries who underwent spine surgery and another major orthopaedic trauma surgery at the same time. Patients who received single stabilization of the spine did not receive any blood products. After the surgery, the neurological state of the patient was evaluated immediately by the surgeon and on the following day, all patients were examined using a CT-scan with 1 mm layer and the screw positions were checked and evaluated. A malposition was defined as a screw not exactly in or perforating the pedicle by more than 2 mm according to Gertzbein [13].
A total of 682 screws were placed in 121 patients. In 33 patients, vertebroplasty was also performed and 61 patients required ventral stabilization which was performed during the same operation in 15 patients and within one week after the first procedure for the other patients (51 × cages, 10 × locking plates with iliac crest bone graft). Fifteen patients required laminectomy. The procedures were performed by 11 experienced trauma surgeons but 71.9% of cases (88 patients) were performed by two experienced spine surgeons. No significant difference in operation duration was found between the surgeons (P > 0.05). No additional nerve injury occurred after surgery; one in five patients showed complete remission of neurological disability after the procedure despite immediate laminectomy after the percutaneous procedure in all patients with neurological disability. In the CT-scan, 16 screws (2.2%) were malpositioned, 8 medially and 8 laterally but no screw perforated the pedicle by more than 5 mm. (Fig. 4) (Table 1) No revision was performed because of the screw position, all screws were
Fig. 3. Percutaneous screw insertion with small incisions.
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
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M. Tinelli et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx
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Table 1 Results of CT-scan after positioning of the screws by surgeons. Age
AO-fracture classification
Fracture height
Trauma surgeon/very experienced spine surgeon
Number of screws
Postoperative CT-scan
17 22 23 26 34 40 45 45 46 46 48 50 51 53 53 55 58 59 59 60 64 67 68 75 75 76 79 80 81 81 88 19 28 43 57 59 59 62 64 64 65 66 68 69 73 75 78 85 45 10 19 41 47 59 50 71 74 76 80 55
A3 A3 A3 A3 A3 A3 A3 A3 A3 B1 A3 A2 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A1 A3 B2 A3 A3 A3 A3 A3 A3 A3 A1 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 A3 B2 B2 A2, A3
L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L1 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2 L2, (L1, L3) L3 L3 L3 L3 L3 L4 L4 L4 L4 L4 L4, 5
TS TS TS VESS VESS VESS VESS TS VESS VESS TS VESS VESS VESS VESS VESS VESS VESS TS VESS VESS TS VESS VESS VESS TS TS VESS VESS VESS VESS VESS VESS TS TS VESS VESS TS TS VESS VESS VESS VESS VESS VESS VESS VESS VESS TS VESS VESS VESS TS VESS VESS TS TS VESS VESS VESS
4 6 4 8 4 4 4 6 6 4 4 4 4 4 4 4 4 4 4 6 6 8 8 4 8 6 6 4 6 4 5 4 4 4 4 6 8 4 6 6 4 4 4 8 4 8 4 4 6 6 4 4 4 4 4 4 4 6 7 8
49 57 20 71 21 76 44 48 59 62 70 72 83
A3 A3 A3 A3 A3 A3 2xA3 A3 A3 A3 A3 B A3
L5 L5 Th 5 Th 5, 7, 9 Th 5/6 Th 8/9 Th10, 11 Th11 Th11 Th11 Th11 Th11 Th11
TS VESS TS VESS VESS VESS VESS VESS VESS VESS VESS VESS VESS
6 4 4 4 8 4 8 4 4 4 8 8 4
Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits L3 right screw 1,2 mm medial Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits L5 left screw 1 mm medial Within normal limits Within normal limits S1 left screw medial intraarticular L5/S1 Within normal limits Within normal limits Th4 right screw 4 mm medial Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
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4 Table 1 (Continued) Age
AO-fracture classification
Fracture height
Trauma surgeon/very experienced spine surgeon
Number of screws
Postoperative CT-scan
72 27
A3 B
Th11, 12, L1 Th11/12
VESS TS
8 4
63 22 26 30 40 45 45 48 48 48 53 61 70 74 76 76 76 82 50 48 47 72 75 83 22 45 61
A3 A3 A3 C2 A3 A3 A3 A3 A3 A3 A3 A3 A1 A3 A3 A3 A3 A3 A3 A3 B A1, A3 B A3 A2 A3 B
Th11/12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12 Th12, L2 Th3 Th3 Th3/4 Th4 Th4, 5 Th5 Th5 Th5, 6
VESS TS VESS VESS VESS VESS VESS VESS VESS VESS TS TS TS VESS VESS VESS VESS TS TS TS VESS VESS VESS VESS VESS TS VESS
6 4 4 6 4 4 4 4 4 4 6 4 6 6 8 4 4 8 6 8 6 5 9 8 8 8 8
27 67 71 79 72 82 77 53 71 87 69
B2 A1, A3 A3 A3 A3 A3 2 × A3, 2xA2 A3 A3 A3 A2, B3
Th5, 6, 7 Th5/6, Th12, Th6 Th6 Th6 Th6, 7; L1 Th6-9 Th7 Th7 Th7 Th7, Th12
VESS VESS VESS TS VESS VESS VESS TS VESS VESS TS
8 8 6 4 6 8 11 4 8 6 8
44 35 36 73 77 18 50 73
A3 A3 A3 A3 A3 2xA3 B1 B1
Th7, 12 Th8 Th8 Th8 Th8 Th9, 10 Th9, 10 Th9, 10
VESS VESS TS VESS VESS TS TS VESS
8 8 8 4 6 8 8 8
Th12 right screw 1 mm lateral Th 11 right screw 3,2 mm medial Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Th11 left screw 4,3 mm lateral Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Th2 right screw 1 mm lateral Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Th4 and 6 left screws 1,5 mm lateral Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Within normal limits Th6 right screw 1 mm lateral Within normal limits Th8 left screw 1 mm medial Th11 right screw 2,2 mm lateral Th6 right screw 1 mm lateral Th6 left screw 2,6 mm medial Within normal limits Within normal limits Th7 right screw 2,7 mm medial Within normal limits Within normal limits Within normal limits
stated as acceptable and no new neurological symptoms occurred. One patient had revision surgery because of local subcutaneous haematoma but without any changing of the implants. The mean duration of the operation was 81 minutes (range 19 to 282) and the mean radiation time was 126 seconds (range 9 to 740) in all patients and for all surgeons including the procedures in multiple injured patients who received spinal stabilization and additional trauma procedures. The mean duration of the operation was 65 minutes (range 35 to 109) in patients with two-level stabilization and four screws. The two experienced surgeons, who performed almost 72% of the operations, had a mean procedure duration of 36 minutes (range 19 to 46) and a mean radiation time of 59.9 seconds (range 20 to 200) for bi-segmental stabilization. 4. Discussion In this study, percutaneous minimal invasive dorsal instrumentation offers correct screw positioning with short operation and radiation times, which was our hypothesis. This procedure is
appropriate for dorsal instrumentation without the need of dorsal fusion. The combination with decompression and laminectomy is possible in any vertebral height. In view of the minimal soft tissue trauma and the minimal blood loss compared to the open technique, it can be recommended for every patient with an urgent indication for surgical spinal stabilization [14]. Dependent of the used implant, multi-segmental percutaneous dorsal instrumentations may not necessarily require long operation times. The disadvantage of this technique is the surgeon’s and operating theatre’s staff’s learning curve but with increasing experience, the array of indications increases from simple type A fractures to distraction-rotation-injuries. A limitation of the technique is the luxation injury and some highly unstable rotational injuries. Beck et al. mentioned the advantage and the exact evaluation of the screw position using intraoperative 3D-visualization [15]. In our study, the rate of malpositioned screws is comparable to those using a navigation system in the literature [16–18]. Perforation of the pedicle is possible because of the individual pedicle thickness, which can be smaller than the screw diameter.
Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015
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5
References
Fig. 4. Postoperative CT-scan with too medial positioning of the screws without new neurological symptoms and without indication for revision.
Some studies show an advantage with screw positioning using robotic techniques because of reduced malpositioning and with that a reduced radiation time and shorter operation time [19,20]. Anand et al. reported an intraoperative blood loss of 260 mL in a series of minimal invasive percutaneous multilevel corrections in degenerative lumbar scoliosis compared to up to 3000 mL using the open technique [21,22]. Blood loss is determined by the technique and comorbidities like septic diseases in spondylodiscitis, patients with malignant diseases or patients with multiple injuries. These patients benefit from a percutaneous minimal invasive procedure regarding the estimated blood loss, if a dorsal instrumentation is required. In this study, the mean operation time for percutaneous bi-segmental dorsal minimal invasive stabilization by an experienced surgeon was 36 minutes with a mean radiation time of 103 seconds. Using other implants with comparable operation times, mean radiation times can exceed 200 seconds [23,24]. 5. Conclusion With this study, the accuracy of percutaneous pedicle screw placement in minimal invasive spine trauma surgery was evident. With short operation times, minimal blood loss, 97.8% of correct screw position and no revision because of malpositioning, this method was absolutely appropriate for the patients in this study. Better accuracy of pedicle screw positioning is no argument for open trauma spine surgery. Disclosure of interest The authors declare that they have no conflict of interest.
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Please cite this article in press as: Tinelli M, et al. Correct positioning of pedicle screws with a percutaneous minimal invasive system in spine trauma. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2014.03.015