Scholarly article on topic 'Dislodgement of a Screw to the Bronchial Tree After Anterior Cervical Plating Surgery'

Dislodgement of a Screw to the Bronchial Tree After Anterior Cervical Plating Surgery Academic research paper on "Clinical medicine"

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{"anterior cervical plating" / "bronchial tree" / "screw dislodgement"}

Abstract of research paper on Clinical medicine, author of scientific article — Tsz-Kit Wu, On-Ming Chung

Abstract Anterior cervical plating is a common procedure that is performed after decompression and reconstruction in cervical spine surgery. Screw dislodgement is a rare but potential complication of cervical plating. The common site of screw migration is within the gastrointestinal tract. Our patient is the first reported case of cervical screw dislodgement to the bronchial tree. It presented ten months after the patient had undergone placement of an anterior cervical locking plate. The dislodgement was confirmed by X-ray imaging, computed tomography (CT) scan, and bronchoscopy. Spine surgeons should be aware of this type of complication in case of screw loosening. Early intervention with implant removal should be considered.

Academic research paper on topic "Dislodgement of a Screw to the Bronchial Tree After Anterior Cervical Plating Surgery"

Journal of Orthopaedics, Trauma and Rehabilitation 17 (2013) 106—108

Case Report

Dislodgement of a Screw to the Bronchial Tree After Anterior Cervical Plating Surgery

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Wu Tsz-Kit*, Chung On-Ming

Department of Orthopaedics and Traumatology, Princess Margaret Hospital, Hong Kong Special Administrative Region, China

ARTICLE INFO

Article history: Accepted December 2011

Keywords:

anterior cervical plating bronchial tree screw dislodgement

ABSTRACT

Anterior cervical plating is a common procedure that is performed after decompression and reconstruction in cervical spine surgery. Screw dislodgement is a rare but potential complication of cervical

plating. The common site of screw migration is within the gastrointestinal tract. Our patient is the first reported case of cervical screw dislodgement to the bronchial tree. It presented ten months after the patient had undergone placement of an anterior cervical locking plate. The dislodgement was confirmed by X-ray imaging, computed tomography (CT) scan, and bronchoscopy. Spine surgeons should be aware of this type of complication in case of screw loosening. Early intervention with implant removal should be considered.

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Introduction

Cervical plating is a common procedure that is performed after anterior cervical decompression and reconstruction. It enhances the stability of the operated cervical spine and subsequent fusion. Screw dislodgement is a risk of the procedure. The common site of dislodgement is within the gastrointestinal tract. We report a patient who had screw dislodgement into the bronchial tree ten months after undergoing anterior cervical plating.

Case Report

A 42-year-old man with ankylosing spondylitis presented with a neck injury after a fall. He had tetraplegia with sensory level at C7. X-ray imaging showed a displaced transverse fracture dislocation over C5/6 (Figure 1). At that time, magnetic resonance imaging (MRI) showed a displaced transverse fracture across the C6 vertebra body and posterior column of C5/6, and severe cord edema from C4

* Corresponding author. E-mail: tszkitwu@gmail.com.

to C7. Mild to moderate cord compression was also noticed. He was initially stabilized with halo traction. Two weeks later, combined anterior and posterior spinal stabilization and fusion were performed. A variable angle titanium anterior cervical locking plate and screws (Synthes, DePuySynthes,Johnson & Johnson, USA) were applied anteriorly and cable wiring was applied posteriorly (Figure 2). The plate spanned from C4 to C7 and the wire extended from C2 to C7. There were no other complications such as wound infection, chest infection, or esophageal perforation.

The patient had mild difficulty in swallowing during his inpatient rehabilitation. Nine months after the operation, X-ray images of his cervical spine showed that one screw had loosened (Figure 3). One week later, he had a follow-up examination in the orthopaedic outpatient clinic. The repeated X-ray images showed one missing screw (Figure 4). The screw was visible on the chest X-ray. Computed tomography (CT) scans later confirmed that the screw had dislodged to the right lower lobe common basal bronchus (Figure 5A and B). A barium swallow did not show any leakage. A CT scan of the cervical spine did not show any retropharyngeal abscess, but did show solid fusion of C5/6. A cardiothoracic team performed flexible bronchoscopy for screw removal. There was no

2210-4917/$ — see front matter Copyright © 2013, The Hong Kong Orthopaedic Association and Hong Kong College of Orthopaedic Surgeons. Published by Elsevier (Singapore) Pte Ltd. All rights reserved. http://dxdoi.org/m1016/jootr.2013.05.013

T.-K. Wu, O.-M. Chung/Journal of Orthopaedics, Trauma and Rehabilitation 17 (2013) 106-108 107

Figure 3. At 10 months, the postoperative follow-up lateral X-ray image shows loosening of one proximal screw.

discharging sinus in the pharyngeal wall. The tracheal and bronchial trees appeared normal during bronchoscopy. At the one year follow-up assessment, he could tolerate regular diet.

Discussion

Screw dislodgement after anterior cervical plating is a rare but potentially devastating complication. The common site of dislodgement is the gastrointestinal tract. The presentation of screw dislodgement varies: oral extrusion of a locking screw and missing anterior cervical plate and screws (presumably passing without notice through the gastrointestinal tract) have been

Figure 2. The postoperative lateral cervical spine shows good alignment and the im- Figure 4. At 10 months after surgery, the anteroposterior cervical X-ray image shows plants in situ show slight nonflushing of the right uppermost screw head. one missing screw at the right most proximal screwhole.

T.-K. Wu, O.-M. Chung / Journal of Orthopaedics, Trauma and Rehabilitation 17 (2013) 106-108

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Figure 5. (A) Chest X-ray shows the dislodged screw in the right lower lung (shadow). (B) Computed tomography scan of the thorax shows the dislodged screw in the common basal bronchus of the right lower lobe of the lung.

reported.1,2 Dislodgement to the bronchial tree, as in our patient, has never been reported.

Loosening of the screw in our patient likely resulted from technical errors such as improper insertion of the screw, inadequate locking mechanism, and insufficient postoperative immobilization

to prevent movement across the motion segments. In retrospective review of the immediate postoperative X-ray imaging, Figure 2 reveals some loosening of the right uppermost screw. His dysphagia was probably caused by esophageal irritation from the loose screw.

There are two possible paths for the dislodged screw to enter the bronchial tree. One possibility is aspiration of the "regurgitated screw" through the vocal cords. The second possibility is that the screw passed through an esophagotracheal fistula created by the loose screw. However, we could not confirm the route with confidence.

In a survey by the Cervical Spine Research Society, esophageal injury at the time of surgery secondary to sharp instruments occurs in 25% of all injuries during anterior cervical procedures.3 Implant failure was the next leading cause of perforation. In 1986, Erwin Morscher first introduced the cervical spine locking plate (CSLP) to prevent screw dislodgement. The early CSLP required drilling, tapping, screw insertion, and applying another locking screw onto the plate. The locking mechanism was achieved by another smaller diameter expansion-head screw. The newer design of the anterior cervical locking plate (ACLP) achieves screw locking by a one-step locking mechanism. The screw has a threaded conical head for locking to the plate. The newest addition to the ACLP family is the Vectra plate. It has the advantage of being constrained (i.e., using all fix-angle locking screws); semi-constrained (i.e., using all variableangle locking screws); or a hybrid (i.e., a combination of fixed and variable-angle locking screws).4,5 Since the introduction of the locking plate, the incidence of screw loosening has decreased markedly.6 A common cause of failure of this implant has nevertheless been related to implant malpositioning. Intraoperative X-ray monitoring is recommended.

In conclusion, we recommend further investigations in patients presenting with persistent dysphagia after anterior cervical spine surgery. A nonflushed screw head (which was visible on the plate in the early postoperative X-ray images) should be a warning sign. Patients should be evaluated for implant-related or graft-related complications. Early removal of implants is indicated if loose screws or dislodged plates become evident and if there is radiological progression.

References

1. Geyer TE, Foy MA. Oral extrusion of a screw after anterior cervical spine plating. Spine 2001;26:1814-6.

2. Fujibayashi S, Shikata J, Kamiya N, et al. Missing anterior cervical plate and screws. Spine 2000;25:2258-61.

3. Newhouse KE, Lindsey RW, Clark CR, et al. Esophageal perforation following anterior cervical spine surgery. Spine 1989;14:1051-3.

4. Aebi M, Arlet V, Webb JK. AO spine manual. Principles and techniques [DVD-ROM]. vol. 1. Switzerland: Thieme Medical Publishers; 200 .

5. Aebi M, Arlet V, Webb JK. AO spine manual. Clinical applications [DVD-ROM]. vol. 2. Switzerland: Thieme Medical Publishers; 2007.

6. Lowery GL, McDonough RF. The significance of implant failure in anterior cervical plate fixation. Patient with 2- to 7-year follow-up. Spine 1998;23:181-6. Discussion 186- .