Intraoperative Crisis Management in Spine Surgery: What to Do When Things Go Bad

Cardiac Arrest

Cardiac arrest in patients who undergo surgery in the prone position is a relatively uncommon phenomenon. Although a history of prior cardiac arrest after general anesthesia is the most significant risk factor, any patient with a significant prior cardiac history is potentially at risk. This underscores the importance of satisfactory preoperative optimization before spinal surgery. Most arrest cases have occurred during major spinal surgery, such as adult or even pediatric spinal deformity surgery. If a patient crashes during surgery and requires cardiopulmonary resuscitation (CPR), the prone position complicates management, owing to several factors. First, the time necessary to procure a stretcher and turn the patient to the supine position to perform CPR delays therapy. The wound must be closed quickly, risking infection and costing valuable time. Interruption of the surgical procedure may also leave the spine unstable, risking spinal cord injury when turning the patient supine. The patient may also be in a headclamp or pins, which will have to be disconnected from the bedframe as well. In patients with significant cardiac history, defibrillator paddles can be placed on either the posterolateral position (one paddle over right scapula and one in the left midaxillary line) or in the biaxillary regions during surgery. This will allow the anesthesia team to deliver synchronous defibrillation if the need arises during the surgery.

In the rare event that turning the patient is not feasible because of an extreme risk of neurological injury, two options are available. The surgeon can initiate CPR in the prone position by placing both hands at the midthoracic level with palms placed over the scapulae and begin chest compressions ( Fig. 85.1 ), if sternal support is present. ^, If there is no sternal support (e.g., the patient is placed on chest rolls), the surgeon may clench one of his or her fists and place it under the patient’s chest over the lower third of the sternum ( Fig. 85.2 ). The surgeon’s other hand (or an associate’s) begins chest compressions at the midthoracic level. “Reverse CPR” as performed in this manner may result in greater increases in systolic pressure as compared with standard CPR and has previously been used in successful resuscitation attempts during neurosurgical procedures.

If these techniques are not possible, a last-resort option is a left dorsal thoracotomy with cardiac massage. Following exposure, open internal cardiac massage and/or defibrillation may be performed ( Fig. 85.3 ).

Vascular Injuries

Anterior Cervical Approach

The Smith-Robinson approach to the anterior cervical spine was first described in the 1950s. Although this approach is effective at treating cervical intervertebral disc pathology, the exposure can theoretically place the common carotid and vertebral arteries at risk for inadvertent injury. The vertebral arteries are at particular risk of injury from the anterior approach, as they run in the cervical transverse foramina just underneath the longus coli ( Fig. 85.4 ).

The carotid artery is typically visualized during exposure and is rarely injured. Blunt dissection and careful use of electrocautery will generally prevent inadvertent injury to the carotids. If brisk small arterial bleeding is encountered, it is usually from injury to the superior thyroid artery.

In a large retrospective review by Härtl and colleagues, the estimated occurrence of carotid artery injury was 1:17,625, thus highlighting the rarity of this type of complication. If carotid artery injury does occur during the case, hemostasis can be achieved with direct manual pressure, blood pressure augmentation, and direct repair of the injury. In severe cases, an intraoperative angiogram may be required.

As mentioned previously, the vertebral artery is also at risk of injury at multiple points throughout the operation. Classically, the rate of injury has been estimated to be somewhere between 0.3% and 0.5%. ^, In a large retrospective review of high-volume surgeons who were members of the Cervical Spine Research Society (CSRS), the estimated incidence of vertebral artery injury was approximately 0.07% (111/163,324). During the anterior approach, incidence was highest during an anterior cervical corpectomy, followed closely by discectomy and during the exposure itself. Interestingly, approximately 20% of these cases involved an anomalous course of the vertebral artery. Injury during the anterior approach can occur because of excessive lateral disc and bone removal, loss of anatomical landmarks resulting in drilling too far off midline past the uncovertebral joint, elevation of the longus colli muscles with electrocautery, and the presence of vertebral artery anomalies.

Vertebral artery injury will result in brisk, high-volume flow of bright red blood into the surgical field, obscuring the surgeon’s view. First, attempts should be made to tamponade the bleeding with hemostatic agents and manual pressure with a cottonoid or 4” × 4” sponge. Once the bleeding has been reduced or controlled, the anesthesiologist should be made aware of the injury and allow time for volume and blood pressure resuscitation if necessary. Primary repair may reduce postoperative morbidity and should be considered as an early intervention to obtain hemostasis if possible, in addition to proximal control. This requires exposure of the vertebral artery one segment above and below the injury, with drilling out of the transverse foramen and skeletonization of the artery. However, if the surgeon is not comfortable proceeding with direct repair, the wound can be closed and the patient brought directly to angiography for stent placement or occlusion. If the patient is hemodynamically stable with satisfactory repair of the injury, consideration should be made to completing the operation.

Posterior Cervical Approach

Vertebral artery injury during posterior cervical decompression and fusion is more common than the anterior approach, however it is still considered relatively rare. In the CSRS study mentioned previously, the most common points at which vertebral artery injury occurred were during posterior instrumentation of the upper cervical spine and during posterior exposure. Injury is most common during placement of subaxial pedicle screws, C2 pars/pedicle screws, and C1‒C2 transarticular screw placement. Injury during exposure can occur when using electrocautery near the C1 posterior arch or lateral and deep to the C1‒C2 facet joint. The rate of injury during C1‒C2 transarticular screw placement has been reported to be as high as 2.2% per screw. Hemorrhage can be controlled by continuing to place the screw into the drill hole or by packing the hole with bone wax. Placing the screw into the drill hole is preferred because it both tamponades bleeding and provides stability. Importantly, the opposite screw should not be drilled or placed. Doing so invites a high risk of disastrous sequelae associated with bilateral vertebral artery injury. As with the anterior cervical approaches, the patient should be taken for an angiogram to evaluate the extent of the injury and whether bleeding is still present.