FAILURE OF A SPINAL IMPLANT OR HARDWARE

Understanding Spinal Implant or Hardware Failure

This comprehensive webpage explores the complex issue of spinal implant or hardware failure.  As such, it addresses the most common types of implants, the causes of failure, and the surgical interventions available. Additionally, the risks associated with implant failures and the likelihood of success in revision surgeries are examined.  Therefore, this page will provide a thorough understanding of this challenging aspect of spinal surgery.

Spinal implants and hardware play a crucial role in stabilizing the spine during surgical interventions. However, like any medical device, these implants can sometimes fail, leading to complications that require careful assessment and management.

Common Types of Spinal Implants and Hardware

The most common spinal implants include pedicle screws, rods, interbody cages, and artificial discs. These devices are utilized in procedures such as spinal fusion or disc replacement. Specifically, they address conditions like degenerative disc disease, spinal stenosis, and fractures.

Detailed Types of Cervical Spine Instrumentation

To delve deeper into cervical spine instrumentation, here are the specific tools commonly used:

• Cranial Screws: Placed at the base of the skull and connected to cervical screws using rods.
• Anterior Cervical Plates: Positioned at the front of the vertebrae with bolts or screws.
• Occipital Plates: Located at the base of the skull and secured with bolts or screws.
• Interbody Cages: Used to restore the height of the spinal segment after the removal of the disc.
• Standalone Cages: Anchored into the bones without the need for screws or plates, potentially reducing the risk of postsurgical swallowing difficulties and hoarse voice.
• Cervical Pedicle Screws: Placed at the pedicles of the cervical vertebrae, these screws are FDA-approved for spinal surgeries.
• Cervical Lateral Mass Screws: Typically used from C3 to C7, these screws are commonly used in spinal surgeries but are not FDA-approved.

Historical Context and Post-Surgical Care

Before screws were introduced for use in the cervical vertebrae, surgeons used stainless-steel wires with bone chips to secure the spinal segments. While modern instruments help fixate the cervical spinal segments, wearing a hard neck brace after surgery is an added measure to ensure successful fusion. The hard neck brace can be replaced with a softer brace after a few days, and the soft brace can be discontinued after a few weeks. However, the screws, rods, and plates typically remain long-term.

Long-Term Complications of Spinal Fusion Instrumentation

Spinal fusion surgery, while helpful for many, isn’t without its risks. Understanding the potential long-term complications can help you make informed decisions. Here are some possible issues you might encounter:

Adjacent Segment Degeneration

When spinal segments are fused, the hardware can alter the spine’s biomechanics. This shift can place extra stress on the segments next to the fused area, leading to accelerated degeneration. Essentially, the segments directly above and below the fusion are prone to faster wear and tear.

Persistent Pain

Post-surgery pain is not uncommon. In some cases, if back pain persists, it may indicate that the hardware isn’t correctly placed. This could necessitate further evaluations and potentially a revision surgery to correct the issue.

Nerve Injury

Although rare, there is a risk that the hardware could irritate nearby nerves or even put the spinal cord at risk. This can lead to sensory changes or motor deficits, requiring medical intervention.

Infection

Surgical procedures always carry a risk of infection. The insertion of spinal instrumentation could trigger new back pain due to infection. Sometimes, these infections are indolent—meaning they’re hidden and not immediately apparent until cultures are taken from the hardware during removal.

Hardware Failure

The fusion hardware could fail if subjected to undue stress, such as lifting heavy objects or engaging in sports too soon after surgery. The hardware might break shortly after surgery or over time if the fusion doesn’t set properly. Implant failures pose several risks, including pain, instability, nerve compression, and a potential need for additional surgery. In some cases, implant failures can lead to complications such as adjacent segment degeneration.  This is where stress on adjacent vertebrae increases, requiring further interventions.

Prominent Hardware

Sometimes, screws or other components may protrude, creating a small but painful bump under the skin. This can occur if the hardware shifts or loosens, often necessitating further surgical correction.

Understanding these potential complications can guide you in monitoring your recovery and seeking timely medical advice if symptoms arise. Always discuss any concerns with your healthcare provider to ensure the best possible outcome.

Causes of Spinal Implant or Hardware Failure

Implant or hardware failure can result from various factors.  The causes include mechanical issues (screw loosening, rod breakage), material failure, inadequate surgical technique, infection, or improper patient selection. Understanding the cause is crucial for determining the appropriate course of action.

Complications from Pedicle Screws in Spine Fusion

Spine fusion surgery, while often effective, carries the risk of complications stemming from the use of pedicle screws. Here’s a detailed breakdown of some potential issues:

Adjacent Segment Degeneration

Pedicle screws can affect the spine’s biomechanics, redistributing stress to segments adjacent to the fusion. This may accelerate wear and tear, leading to degeneration in these areas, and causing pain and further complications.

Persistent Pain

Sometimes, back pain persists even after the surgical procedure. This may indicate a problem with the placement of the screws, potentially necessitating a re-evaluation or revision surgery.

Nerve Injury

In rare cases, screws may irritate nearby nerves or compromise the spinal cord, leading to discomfort or more severe neurological deficits.

Infection

Infections associated with surgical hardware can surface post-operatively. These infections may sometimes be low-grade and only detected through cultures if symptoms like unexplained pain become evident.

Hardware Failure

Pedicle screws can fail, especially if the patient lifts heavy objects or resumes strenuous activities too soon after surgery. This failure might be immediate or apparent over time if the spine doesn’t fuse properly.

Prominent or Loose Hardware

Occasionally, screws may protrude, forming painful bumps under the skin. This can be particularly bothersome if the screws shift or loosen over time.

Blood Clots and Cerebrospinal Fluid Leaks

Specific complications related to pedicle screws include the risk of blood clots in the lungs (pulmonary embolism) and cerebrospinal fluid leaks, which can have severe consequences if not promptly addressed.

Surgical Follow-up: Hardware Removal

If complications arise, a second surgery to remove the hardware may be necessary. However, this isn’t always a guaranteed solution for alleviating pain. Studies show mixed results regarding pain relief post-hardware removal, with less than half of the patients experiencing significant relief.

Removal surgeries are typically shorter than the initial procedures, involving re-entry through the original incision, removal of scar tissue, and partial or complete removal of the screws. In cases where the fusion is incomplete, new hardware might be required.

Understanding these risks helps in making informed decisions about spine fusion surgery and managing expectations post-operation.

Surgical Interventions for Implant Failure

When spine fusion hardware does not achieve the desired results or complications arise, hardware removal surgery may be necessary. This procedure generally involves:

• Incision Re-entry: The surgeon reopens the original incision site. This minimizes additional trauma and leverages the existing surgical pathway.
• Scar Tissue Removal: Any scar tissue that has formed since the initial surgery is carefully excised to access the hardware.
• Hardware Extraction: The surgeon then partially or completely removes the implanted hardware. Depending on the condition of the fusion and the patient’s symptoms, this can involve different levels of removal.

Expected Outcomes

The success and outcomes of hardware removal surgery can vary. Key points include:

• Duration: This surgery is usually shorter than the original spine fusion procedure.
• Pain Relief: While some patients experience pain relief after hardware removal, research indicates that less than half report significant improvement.
• Timing: On average, such surgeries are performed nearly three years after the initial spine fusion.
• Complications: While the procedure can address certain issues, it may not completely alleviate pain or other symptoms related to complications from the original surgery.

Conclusion

Hardware removal surgery can be a necessary step when spine fusion does not proceed as planned. Understanding the procedure and managing expectations regarding outcomes are critical for patients considering this option.