Introduction

Back pain affects millions of people and is one of the most common reasons why patients consult with a medical professional. Many of these patients have back and or leg pain because of lumbar spinal stenosis with or without instability. Conservative treatment in the form of physical therapy, chiropractic care, medications, and injections should be the first line of care if a patient does not present with new neurologic insult. If these conservative modalities fail, then surgery must be considered.

Most lumbar spine surgery involves decompressing the soft tissue, which often includes a herniated disc (Fig. 8-1) or hypertrophied ligamentum flavum. Lumbar spine surgery also involves decompressing the bony elements, which can include hypertrophied facet joints, spinous processes, and lamina that make up the spinal canal. By decompressing both soft and bony tissue, spine surgery can often make patent both central and neuroforaminal narrowing that may be impinging on the spinal cord or nerve roots. Thoroughly decompressing the stenosis and nerve roots can reliably relieve leg pain and its associated symptoms of numbness and weakness. However, there are instances wherein there is obvious instability, spinal spondylolisthesis (Fig. 8-2), or the potential for instability. In this situation, a surgeon must consider both decompressing the stenosis along with stabilizing the affected spinal segments.

Fig. 8-1 Large herniated L4–L5 lumbar disc requiring decompressive surgery.

Fig. 8-2 Significant L5–S1 spondylolisthesis requiring surgery.

Particular ways to achieve fusion of the lumbar spine are discussed throughout the literature. Spinal fusion is a very successful procedure when chosen for patients with the correct indications for surgery. Newer surgical technologies and minimally invasive surgery have been touted to result in quicker recovery and less morbidity for the patient. However, lumbar spinal surgery and fusion with any approach has its associated relevant complications.

Some very serious complications of lumbar spine fusion have been reported, including nerve root injury, paralysis, massive blood loss, blindness, heart attack, stroke, and death. A comprehensive preoperative workup can help to stratify those patients at the most risk for medical complications. In some instances, optimization of a patient’s preexisting medical conditions (e.g., untreated diabetes, hypertension, reactive airway disease) should be taken to minimize their risks before surgery. Expert intraoperative anesthetic monitoring and care, as well as postoperative monitoring, can significantly decrease many of these complications. The surgeon must work effectively and efficiently to address the patient’s disease but also keep operative time as low as possible. Increased operative time often leads to increased complications, including increased blood loss, infection, and possibly blindness from being prone for too long (>8 hours).

The most commonly discussed complications directly related to lumbar spinal fusion include infections, dural tears, pseudoarthrosis, and adjacent segment degeneration (ASD). These specific complications are all important to understand, and if they occur, they must be recognized and treated rapidly, and as such will be elaborated on in more depth.

Selected Complications

Infection

Patients undergoing lumbar spinal fusion typically receive prophylactic intravenous (IV) antibiotics within 1 hour of surgery and postoperatively in several doses. This perioperative regimen, along with proper intraoperative sterility, has decreased infection rates dramatically. However, postoperative spinal wound infection is not an uncommon complication (Fig. 8-3). If not properly recognized and treated, a wound infection can be devastating and affect the ultimate desired surgical outcome.

Fig. 8-3 Normal postsurgical fusion (A) compared with postsurgical infection (B).

A review of the literature shows that postoperative wound infections are common and range from 1% to 6% after lumbar spine fusions.¹ Staphylococcus aureus was the most common pathogen cultured, but some patients have multiple organisms causing an infection. Multiple studies have assessed risk factors for postoperative wound infections (Table 8-1).

Table 8-1 Patient and Surgical Risk Factors for Postoperative Wound Infections

Patient Risk Factors for Postoperative Wound Infections	Surgical Risk Factors for Postoperative Wound Infections
>60 years of age	Complex spine procedures
Smoking	Fusing multiple levels
Diabetes	Spinal revisions
History of previous surgical infections	Anterior or posterior reconstruction
Obesity and increased body mass index	Increased operative times
Alcohol abuse

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