Spinal alignment in adult patients

Spinal alignment, and malignment, has become a popular topic of discussion in spinal surgery over the last few years.

Distinguished consultant orthopaedic spinal surgeon Mr Khalid Salem, provides a detailed guide to spinal malalignment and its surgical treatment in this article. He explains symptoms, effectiveness and risks, among other important points.

What is spinal alignment and when the spine is mal-aligned?

Over the last two decades, our knowledge of the spinal column function evolved. Simply put, we initially thought of it a protective conduit for the spinal cord and cauda equina. A large number of high-quality studies have proven to its role to also extend to the controlling the relationship between the head, trunk and the pelvis, allowing for energy efficient stance and transfer.

This relationship with posture and preservation of energy, led to the emergency of new and exciting domain of spinal subspecialisation dealing with this pathology using a highly complex set of spinal interventions.

The spinal anatomically has a set number of curves in the lumbar (lower back), thoracic (chest spine) and cervical (neck) spine. The magnitude of these curves is highly linked to the shape of the pelvis. Think of the spinal column as a pyramid with its founding stone being the pelvis; the wider the pelvis the larger the curves above it.

When the curve size is “harmonious” and proportional, the muscles around the spine do not need to work hard at all to maintain an upright posture. The situation is “energy efficient”. When the magnitude of these curves’ changes in a certain part of the spine due to degeneration of the spine or trauma for example, the rest of the body will have to compensate in an effort to keep the important position of the head over the pelvis constant and functional to help with walking and looking forward. This “compensation” requires muscle action and subsequent muscle fatigue is painful.

While the mechanisms for compensation for mal-alignment are similar amongst us all, they are limited by the threshold of muscle fatigue and the range of motion limitation within the compensating joints.

Why is this important?!

It all goes back to patient reported symptoms. While some of the patients only suffers mild symptoms due to minimal mal-alignment and a strong muscle core, other suffer very badly primarily due to a significant “decompensation” that surpasses the muscles’ ability to cope.

To objectively understand these symptoms, a number of scoring systems have been utilised such as:

1- The Oswestry Disability Index (ODI) score quantifies the level of functional disability experienced by individuals with low back pain, providing a percentage score ranging from 0% (no disability) to 100% (most severe disability).

2- The EQ-5D score quantifies a person's health-related quality of life (HRQoL) by assessing the severity of problems in five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression.

The extent of the disability associated with the spinal mal-alignment is directly proportional to its problem’s magnitude and at its most severe can be as impactful as blindness, bilateral lower limb amputation and severe heart disease combined!

What investigations do I need to better understand the problem?

Baseline investigations include a whole spine X-ray and an MRI scan of the spine. This offers a good baseline assessment of the spinal alignment and an understanding of the degenerative process and its impact on the neural structures.

Additional testing might also include dynamic X-rays, a CT scan of the spine and a DEXA scan. These offer a more in-depth assessment of the spine by detailing the bony structures, the bone density and subtle instability associated with the condition.

Can the conduction be treated?

Yes, but not in everyone!

It is important to keep in mind that this pathology requires a major reconstructive intervention if alignment is to be addressed. This type of surgery is long and physiologically very strenuous for the patient, has a reported high complication rate (with a 30% severe complication rate) and recovery from it takes months (in hospital stay 7-14 days).

The two major limitations for surgical consideration are:

1- Osteoporosis: the surgery aims to rebuild a collapsed tower. if the bricks are made of marshmallows, the tower will fail. There are ways of increasing bone density pre surgery but they require the use of specific hormone treatment for a minimum of 3 months (ideally 6 months) before the surgery followed by a further assessment of the bone density before proceeding.

2- Frailty: this has been recognised as a major concern due to the significant physiological strain the surgery imposes on the patient’s physiology. A number of scoring systems are available for its assessment but reversing this is a challenge and a multi-disciplinary approach to tackle it is necessary

The final “limitation” is not exactly that but a factor that increase risk and it’s a high weight (BMI). The thresholds for what’s reasonable limit to proceed with surgery remains debatable but logic dictates that the more forward the gravity line passing through the body is, the higher the strain on the metal work at the back and the risk of mechanical failure of the instrumentation.

With all the above in mind, well selected patient for the surgery do very well and clinical studies demonstrated a significant and very impactful positive change to their quality-of-life post-surgery.