Retrolisthesis, also more accurately named retrospondylolisthesis is a spinal condition in which a vertebral body (i.e. the main part of the vertebra rather than a peripheral part such as one of the vertebral processes) is displaced rearwards in relation to the vertebra immediately below it and in some cases, the vertebral body may also be displaced, forwards or rearwards, in relation to the vertebra immediately above it in the spinal column. The name is derived from the Latin preposition retro meaning backwards, back or behind and the Greek word olisthesis meaning slippage. In the more extended version of the name, retrospondylolisthesis, spondylo is another Greek word meaning vertebra. The name spondylolisthesis can refer to slippage in any direction but is most commonly used to describe the anterior (forward) displacement. The amount of vertebral displacement found in retrolisthesis can vary and is normally graded on a scale of 1 to 4, with 4 being the most severe but is less than that associated with a luxation (dislocation).
Retrolisthesis can affect any of the vertebrae but is most commonly seen in the cervical (neck) vertebrae and those in the lumbar (lower back) region. The nature of the symptoms depends largely on the severity of the slippage and may range from localised pain and uneasiness to acute pain, immobility and compensatory distortion of the whole spine. With the most severe grades of retrolisthesis, there may be a mechanical instability of the spine. In many cases, symptoms arise from the misalignment of the intervertebral foramina. These are the openings through which pass nerves, blood vessels and lymph vessels into the spine. If the nerves are pinched at these locations, this can result in both numbness and pain. The pain is not necessarily limited to the immediate vicinity but often manifests itself as radicular pain affecting different parts of the body such as the legs.
The causes of back pain are difficult to diagnose from clinical symptoms alone as similar symptoms can arise from a variety of causes. Many back problems involve soft tissues but retrolisthesis is a skeletal problem and the nature, location and extent of any vertebral slippage can be easily determined by X-rays. These need to be taken from the side and care needs to be taken to ensure that there is no rotation or any other stresses on the spine which could affect the placement of the vertebrae. The X-rays should enable the classification and severity of the condition to be established. The term complete retrolisthesis is used when a vertebral body is in a position posterior to the adjacent vertebrae both above and below. Stair-stepped retrolisthesis refers to a condition where a vertebral body is posterior to the vertebra above but anterior to the one below. In cases where only a single intervertebral joint is involved, this is called partial retrolisthesis.
Grade 1 Retrolisthesis etc.
The severity of this condition is usually assessed by measuring the amount of slippage of the affected vertebral body. This is sometimes simply stated as a numerical measurement in millimetres but the most frequently encountered assessment criteria rely on comparing the amount of displacement to the width of the intervertebral foramina. These are the openings in the spine through which sensory and motor nerves pass. For the purposes of grading, this measured width is compared to the amount of slippage. Grade 1 Retrolisthesis is diagnosed when the measured displacement is up to 25% of the intervertebral foramina width. Up to 50% is grade 2. Grade 3 is up to 75% with any higher measurement being regarded as grade 4.
Retrolisthesis ICD-9, ICD-10
There is an increasing use of specific diagnostic codes for medical conditions and, particularly in the US, this is primarily designed to help with medical insurance claims and billing. The current system, ICD-10-CM, has been in force since 1st October 2015 and retrolisthesis is included under the general category of spondylolisthesis with the codes M43.10 to M43.19, the specific code being determined by the physical location. The previous ICD-9-CM system (prior to 1st October 2015) produced a code of 738.4 but again, a more specific code would depend of the physical location of the problem.
There are various causes of retrolisthesis one of the most easily understood being traumatic injury. There can be specific injuries such as stress fractures of the pars interarticularis but frequently the injury can be non-specific. Such injury can damage the connective tissues causing instability of the joint. The ligaments, discs, muscles, tendons and fascia can all contribute to such problems. The weakened joint may then result in slippage. Degenerative joint disease can also cause this condition and narrowing or bulging discs or end-plate osteophytosis such as in osteoarthritis can result in a weak and unsatisfactory joint. In some cases an early injury often in the early teenage years may initiate such problems which only manifest themselves in later life. In other cases, lack of suitable exercise, poor posture or obesity may all play a part. Spending many hours sitting in front of a computer is certainly not conducive to spinal health. Genetics may also render some people more susceptible to this condition than others.
The chosen methods of treatment for retrolisthesis depends mainly on the severity of the condition including the physical amount of slippage and the the symptoms present. In most cases, especially for grade 1 retrolisthesis, a conservative approach is normally recommended including rest, mobility exercises and the use of anti-inflammatory medication. In more severe cases an epidural steroid injection may be considered but this may only provide relatively short term relief. Many of the main symptoms are a result of nerve pinching usually as a result of foraminal stenosis but occasionally due to central stenosis and treatments normally concentrate on reducing inflammation. Surgical intervention is normally reserved only for the most severe cases where other treatments have proved ineffective.
In severe cases, some additional support such as bracing may initially be required but suitable exercises form the mainstay of conservative retrolisthesis treatment. The exercises are chosen to strengthen specific muscle groups and a suitably qualified physiotherapist is the best choice when formulating a suitable exercise regime. A “hands-on” treatment is also often beneficial in providing pain relief and increased mobility but this is a condition requiring a gentle approach and there is no simple physical way of reversing the vertebral slippage. Some lifestyle changes may also help and improved posture, more exercise and a healthy diet all contribute to the long-term treatment of this condition.