798
LETTERS TO THE EDITOR
patients will be better treated by nonoperative therapy. It should also temper the surgeon’s enthusiasm for surgery when discussing the risks, benefits, and possible outcomes with patients during the informed consent process. In our experience and that of others, not all patients who developed NP failed to benefit from microsurgical repair of their PTN injury.2-4 Such disparities in the success rates could result from many factors; however, improved rates of pain reduction from surgical intervention might be achieved with better selection criteria. The patient most likely to develop NP after a PTN injury 1) is female, 2) underwent surgery late (>6 months after the injury), and 3) did not sustain a complete severance injury but, rather, had a compression injury or developed a lateral or an exophytic neuroma.2 These factors are generally beyond the ability of the consultant microsurgeon to modify. However, an important criterion for the selection of a patient with post-PTN injury NP for surgical intervention, not mentioned by Zuniga et al,1 is the patient’s response to a local anesthetic block (LAB) of the injured nerve.5 If a LAB of the affected nerve gives complete or satisfactory relief of the patient’s NP for the duration of the block, at least a reasonable chance exists that microsurgical exploration and repair of the nerve might achieve some degree (albeit not complete in most cases) of long-lasting or permanent pain relief. However, if the LAB fails to provide pain relief, despite an otherwise good block, the peripheral nerve in question is not the primary reason for the pain, and surgical intervention would not be beneficial and might even exacerbate the pain intensity. The reasons for the pain could be collateralization, ingrowth of cervical sympathetic fibers, central deafferentation, psychological dysfunction, or other poorly understood factors. For such patients, nonsurgical modalities (ie, physical, pharmacologic, behavioral) would be the indicated methods of treatment. Zuniga et al1 have taken an important step forward by reporting their results. Information that leads to the better care of the patient with NP will be beneficial in reducing the suffering of those afflicted.
REPLY To the Editor:—We would like to thank Drs Meyer and Bagheri for pointing out an important fact regarding the neuropathic pain (NP) cohort’s response to a local anesthesia block (LAB) during the inclusion criteria selection in our study. The definition and selection criteria of the patients with NP were described in the sixth paragraph under the subsection ‘‘Patients and Methods.’’ The definition included the use of ‘‘anesthetic or autonomic nerve blocks on level D testing.’’1 We failed to indicate that all the patients with NP in the study cohort had a positive response to LAB (pain resolved with an LAB at inclusion in the study before trigeminal peripheral surgery) and/or negative response to an autonomic block (pain did not resolve with a stellate ganglion block, clonidine, or lidocaine intravenous challenge). All the patients with NP included in our study met the criteria for a ‘‘peripheral source’’ of their NP, as pointed out by Drs Meyer and Bagheri. The supposition that a LAB can distinguish a ‘‘peripheral’’ versus a ‘‘central’’ source for trigeminal NP remains an acceptable step in the process of diagnosis and prognosis. However, the supposition also implies specificity of the pain source and that is far from the reality. As many have reported, the source of NP remains unknown. Melzak and Wall2 correctly stated that ‘‘a peripheral specificity theory would have to find a way in which nociceptors are driven to abnormal activity.’’ Many theories have been proposed for why some patients develop NP and others, with the same injury, do not. Until the etiology of NP is evidencebased and identified, the use of LAB in NP diagnosis, prognosis, and treatment should be considered a guideline for the clinician. We agree with Drs Meyer and Baghheri and continue to use LAB in level D testing as a diagnostic and prognostic indicator for the patient’s response to microsurgery; however, we do not imply to our patients that longterm relief can be predicted according to the outcome of the LAB. JOHN R. ZUNIGA, DMD, MS, PHD DAVID M. YATES, DMD, MD CEIB L. PHILLIPS, MPH, PHD Dallas, TX
ROGER A. MEYER, DDS, MS, MD Greensboro, GA SHAHROKH C. BAGHERI, DMD, MD Marietta, GA
References 1. Zuniga JR, Yates DM, Phillips CL: The presence of neuropathic pain predicts postoperative neuropathic pain following trigeminal nerve repair. J Oral Maxillofac 72:2422, 2014 2. Bagheri SC, Meyer RA, Cho SH, et al: Microsurgical repair of the inferior alveolar nerve: Success rate and factors that adversely affect outcome. J Oral Maxillofac Surg 70:1978, 2012 3. Gregg JM: Studies of traumatic neuralgias in the maxillofacial region: Symptom complexes and response to microsurgery. J Oral Maxillofac Surg 48:135, 1990 4. Pogrel MA, Kaban LB: Injuries to the inferior alveolar and lingual nerves. J Can Dent Assoc 21:50, 1993 5. Meyer RA, Bagheri SC: Clinical evaluation of nerve injuries, in Miloro M (ed): Trigeminal Nerve Injuries. New York, NY, Springer, 2013, pp 167–198
http://dx.doi.org/10.1016/j.joms.2015.01.024
References 1. Zuniga JR, Essick G: A contemporary approach to the clinical evaluation of trigeminal nerve injuries. Oral Maxillofac Surg Clin North Am 4:353, 1992 2. Melzak R, Wall PD: Pain mechanisms: A new theory. Science 150: 971, 1965
http://dx.doi.org/10.1016/j.joms.2015.01.025
A SERIOUS COMPLICATION OF LASER LITHOTRIPSY To the Editor:—We have read with great interest the recent article by Sun et al,1 which describes a patient with multiple large stones in his submandibular gland that were successfully treated under sialendoscopy with laser lithotripsy. We have been performing this procedure at our clinic since 2010, and we have been using laser lithotripsy for the past 2 years. We would like to make a contribution to their article and report a serious complication of this procedure that we have just recently experienced.
799
LETTERS TO THE EDITOR
FIGURE 1. A, Complete obliteration of the main duct of the parotid gland. B, Puncture and dilation of the stricture with balloon dilator. C, Appearance of the duct after dilation. Letters to the Editor. J Oral Maxillofac Surg 2015.
Our patient was a 40-year-old man who presented with a history of recurrent swelling of the left parotid gland for the previous 4 months. Ultrasonography and computed tomography confirmed the presence of a 7-mm stone located in the parotid gland, posterior to the masseter muscle. The patient was informed about the possibility of a combined approach owing to the size of the stone; however, he denied the open transfacial procedure. A Karl Storz sialendoscope with a diameter of 1.6 mm and a working channel of 0.8 mm was used. After locating the stone, it was not possible to retrieve it using a wire basket; therefore, intraoperative lithotripsy using the holmium:yttrium-aluminumgarnet laser (AMS Stonelight, AMS, Minnetonka, MN) carried by a Sureflex fiber, with a diameter of 273 mm, was used (with a power of 2.5 to 3.5 W, rate of 5 Hz/s, and energy of 0.6 J/pulse). The stone was fragmented to smaller dimensions, and many of those pieces were extracted using a wire basket. As reported by Phillips and Withrow2 and others,3 sialendoscopy laser lithotripsy can be a very timeconsuming procedure. Therefore, the procedure was terminated after 2 hours owing to concerns about mechanical trauma and laser heat injury to the duct. A Silastic stent was inserted into the duct, secured with sutures, and left in place for 10 days to prevent stenosis formation. During the postoperative follow-up period, the patient developed recurrence of the symptoms at postoperative day 15. He mentioned that he had constant swelling on the parotid area; however, it was not tender. An ultrasound scan confirmed the presence of a 4-mm stone in the gland. On postoperative day 60, patient underwent another sialendoscopy procedure in which we found that the main duct was totally obstructed approximately 2 to 3 cm distal to the papilla (owing to the unique ductal stenosis described by Marchal et al).4 A Storz dilation balloon catheter was used to perforate, dilate, and irrigate the obstructed duct. The duct could be dilated, but it was not possible to move further in the duct using our sialendoscope (Fig 1). The procedure was terminated, because the patient again had not given consent for an open transfacial procedure. A Silastic stent was again secured, and the patient was informed about the risks of developing a parotid abscess or fistula owing to the presence of the stone and the stricture. Sialendoscopy combined with holmium laser can be effective in the fragmentation of large stones of the parotid or submandibular gland. However, serious trauma to the duct
throughout the procedure should never be underestimated. It is imperative to inform patients of this potential complication, which most probably will result in removal of the parotid gland. ASLI SAHIN-YILMAZ, MD Istanbul, Turkey CAGATAY OYSU, MD Erzincan, Turkey
References 1. Sun YT, Lee KS, Hung SH, Su CH: Sialendoscopy with holmium:YAG laser treatment for multiple large sialolithiases of the Wharton duct: A case report and literature review. J Oral Maxillofac Surg 72:2491, 2014 2. Phillips J, Withrow K: Outcomes of holmium laser-assisted lithotripsy with sialendoscopy in treatment of sialolithiasis. Otolaryngol Head Neck Surg 150:962, 2014 3. Sionis S, Caria RA, Trucas M, et al: Sialoendoscopy with and without holmium:YAG laser-assisted lithotripsy in the management of obstructive sialadenitis of major salivary glands. Br J Oral Maxillofac Surg 52:58, 2014 4. Marchal F, Chossegros C, Faure F, et al: A comprehensive classification. Rev Stomatol Chir Maxillofac 109:233, 2008
http://dx.doi.org/10.1016/j.joms.2014.12.043
REPLY Thank you for your interest in our article.1 We totally agree that the risk of serious trauma to the duct throughout the procedure should never be underestimated. As you mentioned, this is a time-consuming procedure, and we believe that the 1.6-mm sialendoscope might have been slightly large. It would be possible to further decrease the risk of ductal damage by using the 1.3-mm sialendoscope. Moreover, the sialostent has been recommended to be placed over the site at which sialendoscopic procedures have been applied (Fig 1A). Additionally, we would like to share some of our experiences regarding the use of the holmium:yttrium-aluminum-garnet
LETTERS TO THE EDITOR
patients will be better treated by nonoperative therapy. It should also temper the surgeon’s enthusiasm for surgery when discussing the risks, benefits, and possible outcomes with patients during the informed consent process. In our experience and that of others, not all patients who developed NP failed to benefit from microsurgical repair of their PTN injury.2-4 Such disparities in the success rates could result from many factors; however, improved rates of pain reduction from surgical intervention might be achieved with better selection criteria. The patient most likely to develop NP after a PTN injury 1) is female, 2) underwent surgery late (>6 months after the injury), and 3) did not sustain a complete severance injury but, rather, had a compression injury or developed a lateral or an exophytic neuroma.2 These factors are generally beyond the ability of the consultant microsurgeon to modify. However, an important criterion for the selection of a patient with post-PTN injury NP for surgical intervention, not mentioned by Zuniga et al,1 is the patient’s response to a local anesthetic block (LAB) of the injured nerve.5 If a LAB of the affected nerve gives complete or satisfactory relief of the patient’s NP for the duration of the block, at least a reasonable chance exists that microsurgical exploration and repair of the nerve might achieve some degree (albeit not complete in most cases) of long-lasting or permanent pain relief. However, if the LAB fails to provide pain relief, despite an otherwise good block, the peripheral nerve in question is not the primary reason for the pain, and surgical intervention would not be beneficial and might even exacerbate the pain intensity. The reasons for the pain could be collateralization, ingrowth of cervical sympathetic fibers, central deafferentation, psychological dysfunction, or other poorly understood factors. For such patients, nonsurgical modalities (ie, physical, pharmacologic, behavioral) would be the indicated methods of treatment. Zuniga et al1 have taken an important step forward by reporting their results. Information that leads to the better care of the patient with NP will be beneficial in reducing the suffering of those afflicted.
REPLY To the Editor:—We would like to thank Drs Meyer and Bagheri for pointing out an important fact regarding the neuropathic pain (NP) cohort’s response to a local anesthesia block (LAB) during the inclusion criteria selection in our study. The definition and selection criteria of the patients with NP were described in the sixth paragraph under the subsection ‘‘Patients and Methods.’’ The definition included the use of ‘‘anesthetic or autonomic nerve blocks on level D testing.’’1 We failed to indicate that all the patients with NP in the study cohort had a positive response to LAB (pain resolved with an LAB at inclusion in the study before trigeminal peripheral surgery) and/or negative response to an autonomic block (pain did not resolve with a stellate ganglion block, clonidine, or lidocaine intravenous challenge). All the patients with NP included in our study met the criteria for a ‘‘peripheral source’’ of their NP, as pointed out by Drs Meyer and Bagheri. The supposition that a LAB can distinguish a ‘‘peripheral’’ versus a ‘‘central’’ source for trigeminal NP remains an acceptable step in the process of diagnosis and prognosis. However, the supposition also implies specificity of the pain source and that is far from the reality. As many have reported, the source of NP remains unknown. Melzak and Wall2 correctly stated that ‘‘a peripheral specificity theory would have to find a way in which nociceptors are driven to abnormal activity.’’ Many theories have been proposed for why some patients develop NP and others, with the same injury, do not. Until the etiology of NP is evidencebased and identified, the use of LAB in NP diagnosis, prognosis, and treatment should be considered a guideline for the clinician. We agree with Drs Meyer and Baghheri and continue to use LAB in level D testing as a diagnostic and prognostic indicator for the patient’s response to microsurgery; however, we do not imply to our patients that longterm relief can be predicted according to the outcome of the LAB. JOHN R. ZUNIGA, DMD, MS, PHD DAVID M. YATES, DMD, MD CEIB L. PHILLIPS, MPH, PHD Dallas, TX
ROGER A. MEYER, DDS, MS, MD Greensboro, GA SHAHROKH C. BAGHERI, DMD, MD Marietta, GA
References 1. Zuniga JR, Yates DM, Phillips CL: The presence of neuropathic pain predicts postoperative neuropathic pain following trigeminal nerve repair. J Oral Maxillofac 72:2422, 2014 2. Bagheri SC, Meyer RA, Cho SH, et al: Microsurgical repair of the inferior alveolar nerve: Success rate and factors that adversely affect outcome. J Oral Maxillofac Surg 70:1978, 2012 3. Gregg JM: Studies of traumatic neuralgias in the maxillofacial region: Symptom complexes and response to microsurgery. J Oral Maxillofac Surg 48:135, 1990 4. Pogrel MA, Kaban LB: Injuries to the inferior alveolar and lingual nerves. J Can Dent Assoc 21:50, 1993 5. Meyer RA, Bagheri SC: Clinical evaluation of nerve injuries, in Miloro M (ed): Trigeminal Nerve Injuries. New York, NY, Springer, 2013, pp 167–198
http://dx.doi.org/10.1016/j.joms.2015.01.024
References 1. Zuniga JR, Essick G: A contemporary approach to the clinical evaluation of trigeminal nerve injuries. Oral Maxillofac Surg Clin North Am 4:353, 1992 2. Melzak R, Wall PD: Pain mechanisms: A new theory. Science 150: 971, 1965
http://dx.doi.org/10.1016/j.joms.2015.01.025
A SERIOUS COMPLICATION OF LASER LITHOTRIPSY To the Editor:—We have read with great interest the recent article by Sun et al,1 which describes a patient with multiple large stones in his submandibular gland that were successfully treated under sialendoscopy with laser lithotripsy. We have been performing this procedure at our clinic since 2010, and we have been using laser lithotripsy for the past 2 years. We would like to make a contribution to their article and report a serious complication of this procedure that we have just recently experienced.
799
LETTERS TO THE EDITOR
FIGURE 1. A, Complete obliteration of the main duct of the parotid gland. B, Puncture and dilation of the stricture with balloon dilator. C, Appearance of the duct after dilation. Letters to the Editor. J Oral Maxillofac Surg 2015.
Our patient was a 40-year-old man who presented with a history of recurrent swelling of the left parotid gland for the previous 4 months. Ultrasonography and computed tomography confirmed the presence of a 7-mm stone located in the parotid gland, posterior to the masseter muscle. The patient was informed about the possibility of a combined approach owing to the size of the stone; however, he denied the open transfacial procedure. A Karl Storz sialendoscope with a diameter of 1.6 mm and a working channel of 0.8 mm was used. After locating the stone, it was not possible to retrieve it using a wire basket; therefore, intraoperative lithotripsy using the holmium:yttrium-aluminumgarnet laser (AMS Stonelight, AMS, Minnetonka, MN) carried by a Sureflex fiber, with a diameter of 273 mm, was used (with a power of 2.5 to 3.5 W, rate of 5 Hz/s, and energy of 0.6 J/pulse). The stone was fragmented to smaller dimensions, and many of those pieces were extracted using a wire basket. As reported by Phillips and Withrow2 and others,3 sialendoscopy laser lithotripsy can be a very timeconsuming procedure. Therefore, the procedure was terminated after 2 hours owing to concerns about mechanical trauma and laser heat injury to the duct. A Silastic stent was inserted into the duct, secured with sutures, and left in place for 10 days to prevent stenosis formation. During the postoperative follow-up period, the patient developed recurrence of the symptoms at postoperative day 15. He mentioned that he had constant swelling on the parotid area; however, it was not tender. An ultrasound scan confirmed the presence of a 4-mm stone in the gland. On postoperative day 60, patient underwent another sialendoscopy procedure in which we found that the main duct was totally obstructed approximately 2 to 3 cm distal to the papilla (owing to the unique ductal stenosis described by Marchal et al).4 A Storz dilation balloon catheter was used to perforate, dilate, and irrigate the obstructed duct. The duct could be dilated, but it was not possible to move further in the duct using our sialendoscope (Fig 1). The procedure was terminated, because the patient again had not given consent for an open transfacial procedure. A Silastic stent was again secured, and the patient was informed about the risks of developing a parotid abscess or fistula owing to the presence of the stone and the stricture. Sialendoscopy combined with holmium laser can be effective in the fragmentation of large stones of the parotid or submandibular gland. However, serious trauma to the duct
throughout the procedure should never be underestimated. It is imperative to inform patients of this potential complication, which most probably will result in removal of the parotid gland. ASLI SAHIN-YILMAZ, MD Istanbul, Turkey CAGATAY OYSU, MD Erzincan, Turkey
References 1. Sun YT, Lee KS, Hung SH, Su CH: Sialendoscopy with holmium:YAG laser treatment for multiple large sialolithiases of the Wharton duct: A case report and literature review. J Oral Maxillofac Surg 72:2491, 2014 2. Phillips J, Withrow K: Outcomes of holmium laser-assisted lithotripsy with sialendoscopy in treatment of sialolithiasis. Otolaryngol Head Neck Surg 150:962, 2014 3. Sionis S, Caria RA, Trucas M, et al: Sialoendoscopy with and without holmium:YAG laser-assisted lithotripsy in the management of obstructive sialadenitis of major salivary glands. Br J Oral Maxillofac Surg 52:58, 2014 4. Marchal F, Chossegros C, Faure F, et al: A comprehensive classification. Rev Stomatol Chir Maxillofac 109:233, 2008
http://dx.doi.org/10.1016/j.joms.2014.12.043
REPLY Thank you for your interest in our article.1 We totally agree that the risk of serious trauma to the duct throughout the procedure should never be underestimated. As you mentioned, this is a time-consuming procedure, and we believe that the 1.6-mm sialendoscope might have been slightly large. It would be possible to further decrease the risk of ductal damage by using the 1.3-mm sialendoscope. Moreover, the sialostent has been recommended to be placed over the site at which sialendoscopic procedures have been applied (Fig 1A). Additionally, we would like to share some of our experiences regarding the use of the holmium:yttrium-aluminum-garnet
