Stryker InSpace: A Minimally Invasive Solution for Irreparable Rotator Cuff Tears

What is Stryker InSpace?

Stryker InSpace is a minimally invasive, biodegradable balloon system designed to treat massive, irreparable rotator cuff tears, providing a temporary spacer to restore shoulder mechanics, reduce pain, and improve function.

Understanding Rotator Cuff Tears

The rotator cuff is a group of four muscles and their tendons that surround the shoulder joint, providing stability and enabling a wide range of motion. Tears in these tendons are common, especially with age or injury, leading to pain, weakness, and limited mobility. While many tears can be surgically repaired, some are classified as "massive and irreparable." This means the tear is too large, the tissue quality is too poor, or the muscle has atrophied too much for traditional surgical reattachment to be successful or durable. For these challenging cases, alternative treatment strategies are necessary to manage symptoms and restore function.

What is the Stryker InSpace Balloon System?

The Stryker InSpace System is an innovative, arthroscopically implanted device specifically developed for patients with massive, irreparable rotator cuff tears who are not candidates for traditional surgical repair. It consists of a saline-filled, biodegradable balloon made of a resorbable polymer. This balloon is temporarily placed into the subacromial space—the area between the top of the humerus (arm bone) and the acromion (part of the shoulder blade).

How Does InSpace Work?

The InSpace balloon acts as a temporary spacer, effectively creating a cushion that helps to re-center the humeral head within the glenoid (shoulder socket). This mechanism addresses several key biomechanical issues associated with irreparable rotator cuff tears:

• Reduces Superior Migration: In the absence of an intact rotator cuff, the deltoid muscle can pull the humeral head upwards, leading to impingement against the acromion and painful bone-on-bone contact. The InSpace balloon physically prevents this superior migration.
• Improves Glenohumeral Kinematics: By restoring a more centered position of the humeral head, the balloon allows for smoother, more natural movement of the joint, improving the "tracking" of the humerus within the glenoid.
• Facilitates Deltoid Function: With the humeral head properly positioned, the deltoid muscle, which is a major shoulder elevator, can function more efficiently, leading to improved active range of motion and strength.
• Reduces Friction and Impingement: The presence of the balloon reduces direct contact and friction between the humeral head and the acromion, alleviating pain.
• Biodegradable Nature: Over approximately 6 to 12 months, the InSpace balloon gradually resorbs into the body, leaving no permanent implant. This temporary presence is often sufficient to allow the surrounding tissues to adapt, pain to subside, and functional gains to be maintained.

Who is a Candidate for InSpace?

The InSpace system is specifically indicated for:

• Patients with symptomatic massive, irreparable rotator cuff tears: Those experiencing significant pain, weakness, and functional limitations despite non-surgical treatments.
• Individuals for whom traditional surgical repair is not feasible: This includes patients with poor tendon quality, significant muscle atrophy, or those who have failed previous repair attempts.
• Patients who wish to avoid more extensive procedures: Such as reverse total shoulder arthroplasty, or those with comorbidities that make larger surgeries less desirable.
• Often older, less active individuals: While not exclusively, it's a common option for this demographic seeking pain relief and improved quality of life without the demands of extensive rehabilitation from a large surgery.

Benefits of the InSpace System

• Minimally Invasive: The procedure is performed arthroscopically, involving only small incisions, leading to less tissue disruption compared to open surgery.
• Significant Pain Reduction: Many patients experience substantial relief from chronic shoulder pain.
• Improved Range of Motion and Function: By restoring proper joint mechanics, the system helps patients regain active movement and perform daily activities more easily.
• Faster Recovery: Compared to traditional open rotator cuff repair or shoulder replacement, the recovery period can be shorter and less demanding.
• Biodegradable: The balloon resorbs naturally, eliminating the need for removal surgery and leaving no foreign material permanently in the body.
• Preserves Future Options: Should symptoms return or worsen after the balloon resorbs, the InSpace procedure does not preclude future surgical options, such as reverse shoulder arthroplasty.

The Procedure: What to Expect

The InSpace procedure is typically performed as an outpatient or short-stay inpatient surgery under general anesthesia, often combined with a regional nerve block for post-operative pain control.

1. Arthroscopic Access: The surgeon makes a few small incisions around the shoulder joint. An arthroscope (a small camera) is inserted to visualize the joint and the subacromial space.
2. Preparation: Any scar tissue or bone spurs (osteophytes) that might interfere with the balloon's placement are carefully removed.
3. Balloon Insertion: The deflated InSpace balloon is inserted into the subacromial space through one of the small incisions.
4. Inflation: Once correctly positioned, the balloon is inflated with sterile saline, creating the desired spacer effect.
5. Closure: The incisions are closed with sutures or surgical tape.

The entire procedure typically takes less than an hour, though this can vary depending on individual patient factors and any additional procedures performed.

Recovery and Rehabilitation

Recovery following InSpace implantation is generally less intensive than with traditional rotator cuff repair.

• Immediate Post-Op: A sling is usually worn for a short period (e.g., 2-4 weeks) for comfort and protection, but early, gentle range of motion is often encouraged.
• Physical Therapy: A structured physical therapy program is crucial for optimal outcomes. This typically begins soon after surgery and progresses through several phases:
  • Phase 1 (Pain Control & Early Motion): Focus on reducing pain and swelling, and initiating passive and active-assisted range of motion exercises to prevent stiffness.
  • Phase 2 (Gradual Strengthening): As pain subsides and mobility improves, light strengthening exercises for the shoulder and scapular stabilizers are introduced.
  • Phase 3 (Functional Return): Progress to more advanced strengthening, proprioceptive exercises, and functional movements relevant to daily activities and light recreational pursuits.
• Duration: While initial recovery is relatively quick, full functional improvement may take several months as the balloon gradually resorbs and the body adapts. Adherence to the prescribed rehabilitation protocol is paramount for maximizing pain relief and functional gains.

Potential Risks and Considerations

While generally safe, like any surgical procedure, InSpace carries potential risks:

• General Surgical Risks: Infection, bleeding, adverse reaction to anesthesia.
• Balloon Rupture: Though rare, the balloon can rupture prematurely. If this occurs, it typically does not cause harm but may lead to a return of symptoms.
• Persistent Pain or Lack of Improvement: Not all patients experience complete pain relief or functional recovery.
• Adhesive Capsulitis (Frozen Shoulder): Stiffness of the shoulder joint can occur, requiring additional therapy.
• Re-tear: While the InSpace balloon treats the symptoms of an irreparable tear, it does not heal the tear itself. Other nearby tendons may still be susceptible to injury.
• Temporary Solution: It's important to understand that InSpace is a palliative treatment, not a cure for the underlying tendon pathology. Its effects are temporary, and while many patients experience lasting benefits even after resorption, some may eventually require further intervention.

InSpace vs. Traditional Surgical Repair

The key distinction lies in the indication.

• Traditional Surgical Repair: Aims to anatomically reattach the torn rotator cuff tendons to the bone. This is the gold standard for reparable tears and is often chosen for younger, more active individuals with good tissue quality. It typically involves a more extensive recovery period.
• Stryker InSpace: Is designed for irreparable tears where reattachment is not feasible or desirable. It acts as a biomechanical spacer to improve function and reduce pain, rather than repairing the tear itself. It offers a less invasive option with a potentially faster recovery for a specific patient population.

Conclusion

The Stryker InSpace System represents a significant advancement in the management of massive, irreparable rotator cuff tears. For individuals suffering from chronic shoulder pain and dysfunction who are not candidates for traditional repair, InSpace offers a minimally invasive, biodegradable solution that can substantially improve pain, restore shoulder mechanics, and enhance quality of life. As with any medical procedure, a thorough evaluation by a qualified orthopedic surgeon is essential to determine if InSpace is the appropriate treatment option for your specific condition.