The Spine Journal 14 (2014) 2261–2262
Commentary: dysphagia after anterior cervical spine surgery Jung U. Yoo, MD* Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Rd, Portland, OR 97239-3098, USA Received 4 April 2014; accepted 10 April 2014
COMMENTARY ON: Joaquim AF, Murar J, Savage JW, Patel AA. Dysphagia after anterior cervical spine surgery: a systematic review of potential preventative measures. Spine J 2014;14;2246–60 (in this issue).
Dysphagia is commonly reported in the early postoperative period after anterior cervical spine surgery. This is not surprising given the path of dissection and the retraction of esophagus and pharynx during the surgery. The risks can be divided into those that can and those that cannot be controlled. Issues such as revision surgery and multiple level surgeries are already predetermined by the nature of pathology. The factors that can be controlled are dissection, retraction, and implant. However, the development of dysphasia is multifactorial, and controlling one factor may not have a significant effect on the overall occurrence rate. The authors point out many of the surgical factors that can be controlled in their review. These include path of dissection either medial or lateral to the omohyoid muscle. However, they did not comment on the right- versus leftsided approach. One very disabling cause of dysphasia is chronic aspiration brought on by the damage to the recurrent nerve . Although there are many who claim that either approach is safe, the incidence of recurrent laryngeal nerve palsy is rare and it cannot be debated from a single surgeon’s experience. The course of the nerve is less predictable from the right and theoretically more prone to injury. An otolaryngology group reported on 16 patients who had recurrent laryngeal nerve palsy, and 15 of these patients had a right-
DOI of original article: 10.1016/j.spinee.2014.03.030. FDA device/drug status: Not applicable. Author disclosures: JUY: Royalties: Osiris Therapeutics (B, Paid directly to employer); Fellowship Support: Globus Medical, Grant # AORTH0105 (E, Paid directly to institution). The disclosure key can be found on the Table of Contents and at www. TheSpineJournalOnline.com. * Corresponding author. Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Rd, Portland, OR 97239-3098, USA. Tel.: (503) 494-6406; fax: (503) 494-5050. E-mail address: [email protected]
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sided approach . Unfortunately, most patients who have dysphasia due to the nerve injury have a more severe form of dysphasia with limited treatment options. Other surgical strategies require reducing the pressure on the oropharynx and the esophagus. These include lessening the traction time and decreasing the vigorous retraction. However, an adequate amount of retraction is needed to perform the procedure; inadequate retraction may result in accidental puncture of the esophagus, which is a more serious complication than dysphagia. The length of the surgery is also determined by the nature of the problem so cannot be readily controlled. Decreasing the esophageal cuff pressure is a strategy for reducing the damage to the esophagus by decreasing the pressure applied to the esophageal wall. Literature does support that this is a helpful strategy with minimal risk. There are numerous articles cited that support that the profile of the implant may affect the rate of dysphasia . The low-profile implants that are wholly contained within the disc spaces, such as disc replacement and zero-profile fusion implants, are reported to decrease the incidence of dysphasia. This suggests that the volume of material occupying the prevertebral space may be correlated with the development of the dysphasia. However, it is possible that the uneven face of an anterior cervical plate with screw heads and holes may provide sites for soft-tissue attachment between the vertebra and the esophagus. This soft-tissue/scar formation may impede the mobility of pharyngeal movement necessary for swallowing. Therefore, a smooth faced plate such as Zephyr (Medtronic Sofamor Danek,Inc., Memphis, TN, USA) may decrease this softtissue scarring and facilitate movement of the pharynx and esophagus during swallowing. Therefore, it seems prudent to consider the design of the plate and its relation to dysphasia; however, the primary consideration of providing adequate fixation for fusion most likely dominates the
J.U. Yoo / The Spine Journal 14 (2014) 2261–2262
decision-making process. The smooth plate design of Zephyr does not provide multiple levels of fixation and may not be suitable for multilevel surgery. Use of rhBMP (Recombinant human bone morphogenetic protein) in the anterior cervical spine is clearly demonstrated to be associated with dysphasia and breathing complications. Its use should be avoided, given the high union rate that can be achieved in this surgery without the use of this protein. The cost and the risk do not seem to support its use. One factor that is cited by the authors as a cause of dysphasia is prevertebral soft-tissue swelling. However, there are several articles that demonstrate there is no correlation between the soft-tissue swelling and the development of dysphasia. This may be different for massive anterior prevertebral swelling sometimes seen with rhBMP. However, the swelling associated with rhBMP may not be an ordinary hematoma or seroma of the surgical plane. The swelling may instead be an actual swelling of the surrounding tissue mediated by an inflammatory response as many surgeons report that there is nothing to drain when the wound is reexplored.
In conclusion, the authors have accurately described the development of dysphasia as a multifactorial event. As such, it is unlikely that changes in a single variable will have a significant effect on the rate of dysphasia. The reduction of this complication will require careful evaluation in individual surgeon’s approach to every aspect of this surgery. However, surgeons’ awareness of the condition and low-risk steps such as preoperative pharyngeal mobilization exercises may serve the dual role of reducing the risk of developing this complication and informing the patient that this complication can occur. References  Netterville JL, Koriwchak MJ, Winkle M, et al. Vocal fold paralysis following the anterior approach to the cervical spine. The Annals of Otology, Rhinology, and Laryngology 1996;105:85–91.  Weisberg NK, Spengler DM, Netterville JL. Stretch-induced nerve injury as a cause of paralysis secondary to the anterior cervical approach. Otolaryngology Head Neck Surg 1997;116:317–26.  Lee MJ, Bazaz R, Furey CG, Yoo J. Influence of anterior cervical plate design on dysphagia: a 2-year prospective longitudinal follow-up study. J Spinal Disord Tech 2005;18:406–9.