Key-words:
Anterior cervical plating - fistula - locking mechanism
Introduction
The use of anterior cervical approach for spinal surgery pioneered by Smith and Robinson,[[1]] Bailey and Badgley,[[2]] and Cloward[[3]],[[4]] is a commonly performed procedure. Although it is relatively safe and has acquired
extensive approval for high fusion rate,[[5]],[[6]] still it is known to be associated with rare serious potentially life-threatening
complications. We hereby present a rare case of pharyngocutaneous fistula associated
with loosening of locking screw causing internal perforation of the cricopharynx and
Horner's syndrome following anterior cervical plating in a 27-year-old male.
Case Report
A 27-year-old man presented with complaints of left upper-limb weakness and discharge
from neck wound containing contents of consumed food and liquid occurring for 1 year
(see additional file 1 for the video of discharge of consumed food and liquid from
neck wound). He had well-established features of Horner's syndrome such as ptosis,
miosis, anhidrosis, and enophthalmos developed probably due to the loosening of the
locking screw about 1 month postsurgery. He had sustained a gunshot injury to his
neck 1 year back. For management of the gunshot injury, the patient underwent anterior
cervical plating at C5–C7 vertebral level in hospital at his native place. One month
postsurgery, he developed a fistula in the neck which started discharging consumed
food and liquids [[Figure 1]]. Clinically sprouting granulation tissue was present at the opening of the fistula,
located in the left suprasternal area. Neurological examination revealed left upper-limb
reduced handgrip strength. His preoperative imaging workup included plain radiographs,
computed tomography (CT) scan, upper gastrointestinal (GI) endoscopy, and barium swallow.
Plain radiographs revealed loosening of the anterior cervical plate with displaced
locking screw [[Figure 2]]. On GI endoscopy, the presence of a displaced locking screw mechanism was causing
internal perforation of the posterior aspect of the cricopharynx [[Figure 3]]. Barium swallow examination revealed extrusion of the dye through the fistula on
the anterior aspect of the neck.
Figure 1: Clinical photograph revealing sprouting granulation tissue at the opening of the
fistula located in the left suprasternal area
Figure 2: Anteroposterior and lateral radiograph of the cervical spine revealing loose anterior
cervical plate extending from C5 to C7 vertebra. Furthermore, the locking screw can
be seen abutting the posterior wall of the pharynx
Figure 3: Gastrointestinal endoscopy report showing screw lodged in the cricopharynx
Indirect laryngoscopy was done to ensure the integrity of the vocal cords. Considering
excessive scarring and presence of active discharge through fistula on the left side,
the previously unexplored right side was used for anterior cervical spine surgery.
Intraoperatively, pharyngeal wall dehiscence was observed. Considerably large defect
in the posterior pharyngeal wall was noted. Endotracheal (ET) tube and Ryle's tube
could be seen traversing through the deficient part of the posterior pharyngeal wall.
Widespread adhesions between the implant and the overlying structures were released
through sharp surgical dissections, and cervical plate was removed. On further exploration,
dense fibrosis was noted around the locking screw in the cricopharynx. After failed
attempt of removal of impinged cricopharyngeal screw, it was found to be migrated
in the esophageal lumen through the pharynx. This migration of the screw may be attributed
to the deficient posterior pharyngeal wall. Hence, its removal attempt was abandoned.
Preoperative CT scan as well as intraoperative exploration of fusion mass showed solid
union at the corpectomy site; hence, no additional fixation was performed. The patient
was shifted postoperatively to the intensive care unit where he was mobilized on T-piece
intubation. On giving a trial of deflation of the cuff of ET tube, the patient was
experiencing breathlessness due to the collapse of the pharyngeal wall. A plan of
prophylactic tracheostomy was made. Serial radiographs of the abdomen revealed successive
passage of the screw through the gastrointestinal tract (GIT) until finally it could
no longer be visualized [[Figure 4]]. Later, tracheostomy was weaned off. As the patient showed reduced discharge postoperatively,
the GI surgery department gave a conservative trial for fistula to heal with nasogastric
intubation. Currently, the original fistula is showing minimal discharge with no contents
of food [[Figure 5]]. At 2-year follow-up, the fistula has almost healed with no discharge of consumed
food or liquid.
Figure 4: Serial radiographs of the abdomen revealing successive passage of the screw through
the gastrointestinal tract until finally it could no longer be visualized in the last
radiograph
Figure 5: Latest clinical photograph of the patient showing healing wound and nasogastric intubation
Discussion and Conclusion
Implant loosening is known to occur following anterior cervical spine instrumentation.
There are various case reports of oral extrusion of screw or plate loosening causing
pharyngeal wall dehiscence. However, in our case, there was loosening of locking screw
causing perforation of the cricopharyngeal wall which has not been reported till date.
It was a sharp locking screw which migrated from the left to right side and invaded
the cricopharyngeal wall from outside-in manner.
The patient had persistent pharyngocutaneous fistula discharging food contents. Pharyngocutaneous
fistulae are unusual complications of anterior cervical surgery for which literature
quotes the rates to be <0.1% of all anterior cervical surgery cases.[[7]] Newhouse et al.[[8]] mentioned the most common level of perforation being C5–C6 as this level corresponds
with pharynx and its transition to the esophagus. Our case had instrumentation being
done at the same level. Apart from transition, the thickness of the pharyngeal wall
is less in this region compared to other regions making it vulnerable to injury. There
are two mechanisms of injury to the pharynx which leads to the formation of pharyngocutaneous
fistula postinjury/surgery. The first one can occur following primary injury due to
sudden hyperextension injury to the pharyngeal wall along with spinal injury. This
leads to tear in the posterior pharyngeal wall and can be missed easily unless high
index of suspicion is exercised for it. The second one can occur due to intraoperative
pharyngeal wall dehiscence by inadvertent retraction of the pharyngeal wall along
with sharp instrumentation technique like the use of burr. Unfortunately, such injury
is not evident unless specifically looked for intraoperatively by various maneuvers
such as methylene blue dye insertion.
Development of late pharyngocutaneous fistula can occur due to perforation by implant
or loose screw. This mode of late perforation of the upper GIT due to implant loosening
is very rare nowadays with the advent of low-profile ergonomic designs of the Anterior
Cervical Plating (ACP) system. As our patient did not have any records of index surgery,
it was difficult to speculate any reason for fistula formation in our case. However,
history suggested of continuous discharge from surgical wound culminating later in
fistula formation. Hence, we suspect it to be case of intraoperative pharyngeal wall
dehiscence. Wound infection, fever, salivary discharge from wound, mediastinitis,
and features of sepsis in immediate postoperative period are suggestive of visceral
injury to pharynx or esophagus depending on the level of surgery. GI endoscopy along
with imaging like CT scan and barium swallow delineates defect and confirms diagnosis.
As our case presented to us 1 year after index surgery, treatment strategy differed
from acute presentation of fistula where direct/primary repair of the pharyngeal wall
is the mainstay of treatment.[[9]]
Handling of late presentation of pharyngocutaneous fistula requires a multidisciplinary
approach. As per GI surgeons, controlling infection was the first step before they
could consider any form of reconstruction. Hence, a combined plan for implant removal
was done including removal of cricopharyngeal screw. Intraoperatively, a considerably
large defect in the posterior pharyngeal wall was noted. Postoperatively, discharge
from the neck reduced significantly. ENT and GI surgeons who considered option of
local muscle flap preimplant removal decided to give conservative treatment for fistula
by nasogastric feeding. The patient responded well to the above treatment with minimal
discharge and complete stoppage of food contents in discharge.
Usually, chronic pharyngocutaneous fistula requires the use of local sternocleidomastoid
muscle[[10]],[[11]] or omohyoid flap along with VAC application to keep salivary secretions away from
the site of repair. Sternocleidomastoid flap detached from the clavicular end is preferred
option because of the ease of access, easy mobilization, and reduced chances of microthrombosis
in its vasculature. There are anecdotal case reports in literature about the management
of pharyngocutaneous fistula with no major series of more than five patients.[[12]],[[13]]
The presence of plate locking screw in the cricopharynx highlights the necessity of
robust locking mechanism for screws in plate with quality control during manufacturing
process. The patient also showed features of Horner's syndrome due to damage to the
sympathetic chain during index surgery which was managed in consultation with an ophthalmologist.
This highlights careful precautions needed to dissect longus colli subperiosteally
with minimal use of thermal coagulation over the surface of muscle to avoid damage
to sympathetic chain. As we had interbody fusion noted both intraoperatively after
removal of anterior cervical plate and on preoperative CT scan, we did not require
further posterior instrumentation.
Conclusion
This case report highlights a rare complication of faulty locking screw invading the
cricopharyngeal wall along with postoperative pharyngocutaneous fistula discharging
food contents following suspected intraoperative injury to the pharyngeal wall.
Clinical Message
Having knowledge of this possible rare outcomes and awareness of various multidisciplinary
approaches for their management makes practicing spine surgeon equipped to handle
such undesirable complications.
