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Role of the InSpace Balloon in Rotator cuff Tears

This presentation describes the potential indications, surgical technique and results of the biodegradable subacromial spacer.


My name is Gavin Jennings. I’m a shoulder surgeon in Bath, UK.
The following presentation discusses the use of the InSpace Balloon in the treatment of Rotator cuff tears. 

The InSpace ballon is a biodegradable subacromial spacer made from PLA and epsilon-caprolactone. It can be implanted arthrosocpically or fluoroscopically and is said to fully degrade within twelve months of implantation

It works by reducing friction between the humeral head and the acromion and also reproduces the depressor effect on the humeral head which has been lost as a result of cuff failure. These benefits facilitate the progression of the subsequent anterior deltoid rehabilitation programme. 

Active infection, known allergy to the Balloon constituents, Grade 3 or 4 OA and pseudo paralysis are considered contraindications to its use.

It’s main indication is in irreparable cuff tears with pain and reduced function. Other indications have been proposed such as its use above partial or margin convergence repairs, above large but complete repairs and even above repairs with patch augmentation.

Arthroscopic insertion starts with a limited debridement through a lateral portal. A reservoir of N Saline is attached to the inserter and the ballon is inserted through the same portal. The protective sheath is withdrawn and the balloon is fully inflated. Some saline is then withdrawn and the plug inserted. The inserter is removed and the arm taken through range of motion to ensure the balloon is stable.

There are a few tips which may help make the technique straight forward. 
Firstly, ensure that the balloon itself and the normal saline are warm to assist the unfurling process.  The lateral portal should be made at the zenith of the humeral head (i.e.it  may be in a slightly different position than the standard portal. Debridement should be minimal- just enough for the inserter to pass and the balloon to inflate in a superior and central position. Avoid Excessive anterior and posterior debridement should be avoided and  an SAD should not be performed. The correct ballon size is determined with a graduated probe- the skin is pinched at the port site then measurement is then from portal to glenoid face, then  one cm is added to this measurement. The small balloon is rarely used and most males seem to need the large. It is important to ensure that the lateral portal is dilated adequately to allow smooth passage of the inserter through the soft tissues and in a straight line over the superior glenoid rim. It’s advisable to cycle the arm a few times whilst observing the inflated balloon to ensure stability.

This video of a right shoulder viewed from posterior shows the debridement, mainly superiorly, the measurement taken with the skin pinched, smooth insertion of the balloon without any torque on the inserter, placement of the Balloon above the superior most part of the glenoid, and inflation.

Recommended  guidelines for rehab are provided by InSpace as shown. I tend not to restrict power movements as long as recommended and just let patients progress as able after six weeks. A temporary loss of function and increase in pain at the 8 to 12 week period, presumably at the point at which the balloon bursts, is often seen. It often takes a few weeks to recover from this trough.

As regards to complications of the 14,000 ISB’s inserted since 2010, there has been a reported medical adverse event rate of 0.32% including infection, balloon migration, severe post op pain and most commonly allergic reaction to the implant. 

There are a number of relatively small studies related to the use of the balloon but  a couple are worth of mention.

The first study was a prospective case series from Slovenia and Israel with 20 patients with RC Tears greater than 5 cm. 

This showed significant improvements in Constant Score (up 33 points) ROM, pain and ADL’s maintained at three years. Power took a long time to improve but improvement was sustained.

Here’s a graphical representation of the improvements at various time points up to three years.

Last year the 5 year results of this cohort were published and the improvements were all maintained.

Deranlot et al looked retrospectively at 39 cases with the series being published in Arthroscopy in 2017

All patients had an intact subscapularis and the biceps, if intact was tenotomised. Significant improvements in ROM were seen with a increase in the Constant score of 21

The existing literature is thus not exactly robust and we still have more questions than answers about the uses of the InSpace Balloon. For example is a balloon better then simple debridement, is a balloon better then a partial rotator cuff repair. Should balloons be used in addition to massive cuff repairs or augmented repairs?

NICE have produced guidance  which essentially states that at present evidence for use is limited and thus the ISB should only be used in the context of research. In real terms this means that patient outcomes data collection and adequate follow up must be performed. The company also insists that the cases are supported

Thus it is clear that adequately powered RCT’s are needed.
Approval by NIHR is hopefully imminent for a multi-centre study from Warwick Clinical Trials Unit comparing debridement vs balloon plus debridement. This represents a far more robust version of the comparison performed by Agneskirschner in 2016.

There is also a US study currently recruiting comparing ISB versus repair or partial repair of massive cuff tears and unlike the previous similar US study, it looks as though the recruitment levels will be achieved in time to proceed with the study.

So in summary, the InSpace ballon looks like a very promising option in the sphere of massive rotator cuff tear management, but we have some way to go before we understand it’s exact indications. Many thanks.