Introduction
Revision lumbar spine surgery comes with unique challenges and special considerations in the postoperative setting. In this chapter, we will cover some topics pertinent to postoperative care. Specifically, we will cover drains, antibiotic prophylaxis, venous thromboembolic prophylaxis, bracing, and physical therapy.
Postoperative Drains
Current literature does not strongly recommend for or against the use of postoperative drains following lumbar surgery. In particular, limited literature exists about drains in the realm of revision spinal surgery. Proponents of drains argue that judicious use can decrease rates of hematoma formation, lower the burden of exudate within deadspace, and decrease the risk of infection. The location of drains can vary from subfascial to suprafascial. Subfascial placement can serve to protect exposed neural structures from deep exudate and hematoma formation. In patients with deep wounds and a pronounced fat layer between the fascia and skin, a suprafascial drain may address exudate and blood in this potential deadspace.
Unfortunately, no consensus exists on the exact indications for drain use, location of placement, duration, and thresholds for drain output before removal. A multicenter retrospective study assessing the use of closed suction wound drains in posterior spinal fusions for scoliosis found that 72% of surgeons used drains. Of those who used drains, close to half stated that drains were used based on habit and without specific reasoning. Other less frequent reasons included concern for excessive bleeding, open vertebral canal, or an elevated international normalized ratio (INR). Only 6 of the 50 surgeons involved in the multicenter study specifically cited revision cases as an indication for drain placement. Roughly half of the surgeons removed drains based on a drain output threshold of less than 30 mL per 24 hours, whereas others removed them after a set time (1–3 days) regardless of the exact drain output.
Several studies argue that drains may actually have a detrimental effect. Adult reconstruction literature suggests that drains may be associated with higher rates of blood transfusion. Transfusion rates were similarly found to be higher in patients with drains than those without drains when undergoing posterior spinal fusion and instrumentation for scoliosis. Furthermore, the potential benefits of drains have not been clearly supported in the literature. Rates of wound infection, general infection, and neurological injury (from space-occupying lesions such as hematoma) were equivalent among patients, with and without drains, after undergoing thoracic and lumber spinal surgery. Some studies suggest that patients with postoperative drains may actually have higher rates of infection. Even the use of perioperative antibiotics for the duration of the drain does not decrease the risk of infection from the drain itself.
The decision to use or avoid a negative pressure drain in the postoperative setting of spinal surgery can be complex and only becomes more difficult in revision spinal surgery. In revision cases, dissection planes can be substantially altered, which affects the integrity of the fascia and muscle. Concerns arise about hematoma formation, development of neurological deficits, the presence of deadspace, and postoperative infection. Given the paucity of evidence to clearly support drains after spinal surgery, distinct, thoughtful, and goal-oriented reasoning should be applied before drain placement, on an individual patient basis. Placement of a drain does not eliminate the risk of complications. Continued prudent care is imperative with clear criteria in mind for timely drain removal.
Perioperative Antibiotic Prophylaxis
Discussion of perioperative antibiotics during revision lumbar spinal surgery depends heavily on the indication for the revision operation. With noninfectious revisions, preoperative antibiotics are started before surgical incision. Typically, a first- or second-generation cephalosporin such as cefazolin or cefuroxime are the agents of choice. National surgical infection prevention guidelines and North American Spine Society (NASS) guidelines help direct the use of perioperative antibiotics. Cephalosporins should be started within 60 minutes of the surgical incision. In patients with a true, life-threatening beta-lactam or cephalosporin allergy, alternative antibiotic options include clindamycin and vancomycin. Vancomycin in particular must be started within 120 minutes of the surgical incision, which allows time to assess for an antibiotic-related adverse reaction. In noninfectious revisions, antibiotics are typically continued for no longer than 24 hours. Postoperative antibiotics beyond 24 hours do not appear to further decrease rates of surgical site infection and may actually contribute to antimicrobial resistance. According to the NASS grade C guidelines, prolonged antibiotic use can be considered in patients with substantial comorbidities such as trauma, diabetes, obesity, incontinence, or neurological deficits. In cases involving postoperative drains, continuation of antibiotics for the entire duration of drain placement does not appear to provide any additional protective effect against surgical site infection beyond the standard 24 hours.
Antibiotic use, selection, and duration differ during revision surgery done for infection as opposed to noninfectious reasons such as instrumentation failure or adjacent segment disease. In the setting of infection with no clear identification of pathogen, preoperative antibiotics are often held to prevent interfering with intraoperative culture results. Instead, the antibiotics are started after multiple cultures are obtained during the revision operation. Initially, broad-spectrum antibiotics are started and continued during the postoperative period. The antibiotics are then tailored pending intraoperative culture results and input from infectious disease colleagues. The duration of antibiotics varies based on the nature of infection, retention of implants, or staged instrumentation removal, with reimplantation at a later date.
Postoperative Venous Thromboembolism Prophylaxis
Thromboembolic prophylaxis in revision lumbar spine surgery involves the delicate balance between the risk of venous thromboembolism (VTE) versus postoperative spinal epidural hematoma (SEH). Rates of VTE events in major thoracolumbar spine surgery range from 1.5% to 4.3%. The exact incidence of postoperative SEH is unclear. The reported incidences for symptomatic SEH vary from 0.22% to 1%. Risk factors for SEH include multilevel surgery, history of coagulopathy, and revision spinal surgery.
Despite a relatively low incidence of postoperative SEH, the associated morbidity can be catastrophic. Symptoms include acute back pain with possible new neurological deficit. In addition to careful physical examination, urgent advanced imaging with computed tomography (CT) or magnetic resonance imaging (MRI) is imperative, which can help to localize and assess size, and evaluate surrounding neurological structures. Symptomatic SEH with neurological deficits can require immediate surgical evacuation. Concern for this substantial morbidity can be a deterring factor in the use of VTE chemoprophylaxis.
A 2014 retrospective study assessed the implementation of a multimodal approach to VTE prophylaxis in patients undergoing spinal surgery. The protocol comprised the use of sequential compressive devices and use of subcutaneous heparin starting either preoperatively or on the day of surgery. The study compared rates of VTE events pre- and postimplementation of the new protocol and found that the multimodal prophylaxis decreased overall VTE events from 3.3% to 1.5%. Additionally, rates of SEH did not increase with implementation of the multimodal prophylaxis protocol. In 2009, the NASS issued guidelines pertaining to VTE prophylaxis. They stated that posterior-based, elective spinal surgeries have low rates of VTE events and may not need routine VTE prophylaxis. Use of sequential compressive devices and early, safe mobilization were encouraged. They did state that low-molecular-weight heparin can be considered postoperatively in the setting of combined anterior-posterior spine surgery and in patients with a history of thromboembolic disease, malignancy, and trauma. The guidelines do not explicitly address the use of chemoprophylaxis in revision lumbar surgeries. Revision spinal surgery is a risk factor for hematoma formation, and the use of chemoprophylaxis needs to be tailored to the individual patient based on comorbidities.
Spinal Orthoses
Historically, postoperative bracing has been thought of as an adjuvant to protect fixation and provide additional stability. For example, in cases involving substantial vertebral osteotomies (deformity correction) or those with poor implant fixation (i.e., osteoporosis), bracing can be used as supplementary support for spinal stability. Additionally, bracing can prove helpful in staged revisions that may involve partial or complete instrumentation removal with subsequent reimplantation at a later date. The choice of specific orthoses varies based on procedure, extent of dissection, and vertebral levels involved. Generally, braces should extend beyond the involved vertebral levels of the procedure. For procedures involving lower thoracic and lumbar spine, a thoracolumbar sacral orthosis (TLSO) brace can be applied ( Fig. 21.1 ). For cases involving only lumbar segments L3 and below, an LSO brace may be more appropriate. The benefits of bracing may include alleviation of pain and possible facilitation of fusion. Furthermore, bracing has not been associated with increased rates of reoperation or complications.
