Neurological Complications of Common Spine Operations

Occipitocervical Junction

Neurological complications can occur during surgery at the occipitocervical junction, but compared with other regions of the spine, complications in this location are rare. The underlying anatomic and biomechanical complexity of the occipitocervical junction poses unique challenges that may lead to complications. Neurological sequelae may result from the compromise of neural, biomechanical, and/or vascular structures in this region. Although it is rare, these sequelae may result in a variety of neurological injuries, including occipital neuralgia, spinal cord injury, and stroke secondary to vertebral artery injury (VAI). The neurological complications in this region are often associated with significant patient morbidity and mortality.

Occipital neuralgia is a distinct type of burning pain located mainly in the occipital and upper neck that partially extends to the vertical, retroauricular, retromandibular, and forehead areas. One possible cause after posterior upper-cervical spine surgery is C2 neuralgia, which can occur from manipulation, thermal injury, or stretch injury during placement of C1 lateral mass screws and/or exposure of the C1‒C2 facet capsule. The pain can often be associated with paresthesias or numbness. Recent literature suggests that the prevalence and intensity of postoperative neuralgia is significantly higher with C2 nerve root transection than with its preservation. Treatment includes medications, nerve blocks, nerve stimulation, and revision surgery. Unfortunately, the pain is often persistent and difficult to cure, but incidences vary widely in the literature.

Anatomic foramina in the occiput and cervical spine house critical structures that include exiting nerves or blood vessels, and these foramina may be compromised with improperly placed instrumentation. Although direct injury to the spinal cord is rare during instrumentation, liberal use of fluoroscopy or image guidance is a common mitigating technique during occipitocervical fixation. Intracranial extension of occipital screws could cause occipital meningismus, resulting in persistent headaches, hemorrhage, or spinal fluid leak. Screw violation into the neural foramen may cause focal radiculopathies. ^, Avoiding vital structures becomes increasingly difficult when the underlying anatomy is remodeled in the setting of prior surgery, bone pathology, or anatomic variants. Although complications in this region could result in irreversible and devastating injuries, careful and meticulous surgical technique is critical to avoid such problems. Identification of reversible etiologies, dynamic interpretation on neuromonitoring changes, appropriate operating room team communication, and optimization of the operative environment are paramount when an iatrogenic spinal cord injury is suspected intraoperatively.

VAI is a rare but serious complication of cervical spine surgery, with the potential to cause catastrophic bleeding, permanent neurological impairment, and even death. Improper screw placement into the transverse foramen is the most common cause of VAI in posterior cervical spine surgery. ^, A recent survey of Cervical Spine Research Society members yielded an overall VAI incidence of 0.07% in over 160,000 cervical spine surgeries. Posterior instrumentation of the upper cervical spine (32.4%), anterior corpectomy (23.4%), and posterior exposure of the cervical spine (11.7%) were the most common stages of the case to result in an injury. One-fifth of VAIs involved an anomalous course of the vertebral artery, again underscoring the importance of reviewing preoperative imaging. The most common management of VAI was direct tamponade, with outcomes predominately involving no sequelae in 90% of patients. Permanent neurological sequelae (5.5%) and death (4.5%) are rare but devastating outcomes.