Since the diagnosis of cervical spondylosis was clarified in the middle of the last century, cervical spine surgery in China has made rapid development in the past half century.
Looking back to the 1950s, many scholars did not yet recognize cervical spondylosis, and it was accepted by everyone in the early 1960s. At that time, the diagnostic criteria were mainly based on clinical symptoms and positive plain X-rays, and most of the treatment options were light weight continuous traction (3~4 weeks) plus jaw-thorax cast fixation (March), with an efficiency rate of 90%. In severe cases, fusion of the vertebral segments is performed, i.e., the vertebral segments are fixed and the bone spurs are gradually absorbed to reduce the compression and improve the symptoms. Although this procedure is effective, it takes too long and is difficult to end the progression of the lesion. Therefore, in the mid-1970s (1976), the authors proposed an expanded anterior cervical decompression with the aim of removing the compression-causing material (bone and disc), which was recognized for its immediate effect and thus provided a new beginning for surgical intervention in cervical spondylosis. three years later, artificial intervertebral joints and artificial discs were proposed for functional reconstruction, which also achieved initial results.
After more than a decade of hardship, the incidence of cervical spondylosis has increased dramatically with the advent of an aging society, the rise of computers and the Internet, and the increasing number of desk-bound workers in China in the 1990s, with a trend toward younger and more diverse people, and a prevalence of more than 27% among college students. Due to the sudden increase in clinical cases, even if one percent of the patients need surgery, the number is still very significant. In this state, cervical spine surgery can be carried out in all regions of the country, including county hospitals; coupled with the continuous improvement of surgical instruments and the widespread use of internal fixation materials in recent years, not only has our cervical spine surgery entered the ranks of internationalization and modernization; but also due to the cultural heritage and dexterous hands of the Eastern people, the unique characteristics of our national surgical techniques have been highlighted. Therefore, from the clinical point of view, China has leaped to the ranks of the world’s advanced in the diagnosis and treatment of cervical spondylosis, especially in surgical treatment.
While cervical spine surgery is widely carried out, the complications and sequelae brought about by the surgery have also increased, with the incidence ranging from 2% to more than 10%, resulting in an exponential increase in return (revision) surgery every year by the turn of the century. In view of this situation, it is necessary to reflect on some basic issues of cervical spondylosis, especially some issues related to diagnosis and treatment, which should be re-understood and emphasized in order to further improve the diagnosis and treatment of this disease.
I. Several issues related to the diagnosis of cervical spondylosis
1. The naming of “cervical spondylosis” (Cervical Spondylosis)
More than 20 years ago (1984), many scholars at the First National Symposium on Cervical Spondylosis in Guilin suggested that the name “cervical spondylosis” was inaccurate and too general, but today, more than 20 years later, it is difficult to find a more appropriate new name. This year (2008), the American Academy of Orthopaedic Surgery (AAOS) still uses the term Cervical Spondylosis to summarize cases of myelopathy, radiculopathy, and vertebral artery type that cause sympathetic symptoms such as headache; of course, the causes of these cases are all derived from cervical degeneration. In this state, whether a more precise name can be found to replace the term “cervical spondylosis” with its complex symptoms, numerous subtypes and generalized concepts is yet to be discussed and agreed upon in the future.
2.The main basis for early diagnosis of cervical spondylosis Due to the popularity of magnetic resonance imaging (MRI) diagnostic technology, clinicians naturally choose MRI to confirm the diagnosis and typing of cervical spondylosis when receiving patients; this has been agreed upon by everyone. However, at the earliest stage of cervical spondylosis, that is, when the intervertebral disc has just started to degenerate, symptoms such as instability and loosening of the vertebral segment caused by dehydration of the nucleus pulposus and pain and discomfort in the neck due to irritation of the sinuso-vertebral nerve in the cervical segment may not be seen positively during MR examination; however, the trapezoidal changes caused by loosening and displacement of the vertebral segment can be shown on the lateral dynamic X-ray of the cervical spine, and an early diagnosis can be made as a result. Therefore, from a diagnostic and therapeutic point of view, especially when deciding on the extent of the vertebral segment to be operated, lateral cervical dynamic radiographs should be routinely performed in conjunction with MR examinations to determine early degeneration of adjacent vertebral segments. At present, our hospital has started to observe and explore the correlation between vertebral segment and spinal cord compression in cervical spine dynamic position through MR examination, and the preliminary results show that it is clearer than general MR examination; the final conclusion is yet to be observed.
At least 1/4 of the cases of frozen shoulder are due to cervical spondylosis. Clinically, frozen shoulder is common in the age group of about 50 years old, so it is commonly known as “fifty shoulder”. However, we have encountered many patients with frozen shoulder who have not been treated for a long time and have even undergone shoulder arthroscopy or periarthroscopic release. After clinical and imaging examinations, we found that this group of cases was actually due to cervical spondylosis affecting the fourth and fifth cervical spinal nerve roots; after carefully observing more than a thousand cases of cervical spondylosis over the past thirty years, we found that at least 25% of the patients with “frozen shoulder” were due to cervical spondylosis. The initial diagnosis can be made after gentle upward traction of the head and neck, when the cervical 4 and 5 spinal nerves innervating the shoulder are released and the symptoms are relieved; the diagnosis is then confirmed based on MR findings; and treatment is provided according to cervical spondylosis, including continuous traction of the head and neck and surgical treatment.
4. Recognize anterior central spinal artery syndrome Spinal cord-type cervical spondylosis due to anterior spinal cord compression is not uncommon; however, if the anterior central spinal artery compression alone causes symptoms of motor disorders due to insufficient blood supply to the anterior spinal cord, accompanied by cranial or sympathetic symptoms of varying degrees and symptoms, we call it anterior central spinal artery syndrome; this vascular data has been obtained from imaging. The anterior central spinal artery originates from the vertebral artery, and when its compression leads to obstruction of blood flow, various symptoms can be induced by increased pressure in the vertebral artery and stimulation of the sympathetic postganglionic fibers around the vertebral artery, including anterior spinal cord ischemia, inadequate blood supply to the V-II vertebral artery, and sympathetic dysfunction. The symptoms vary with neck position, are aggravated by neck flexion, and are relieved by traction. The MR imaging features are not very serious, so they are easily misdiagnosed as other disorders. In this group of patients, surgery is based on decompression of the middle part of the intervertebral space plus propping, and the authors have performed dozens of cases with satisfactory results, which will be introduced in the form of a special topic.
5, pay attention to the hook protrusion and hook joint lesions The hook protrusion is the earliest site of cervical spine degeneration, but it is often overlooked because it is not easy to observe on cervical spine plain film; in fact, it is one of the bony pressure-causing factors in front of the spinal cord. Therefore, for those who intend to operate for cervical spondylosis, preoperative attention should be paid to the determination of the lesion here; CT scan and 3D reconstruction can be done if necessary. If we focus only on the disc lesion and ignore the lesion at the levator, the outcome will be affected. In fact, clinical cases of compression of the vertebral artery and spinal nerve roots due to hyperplasia and loosening of the leptomeningeal joint are more common; therefore, the abnormal status of the leptomeningeal joint (hyperplasia and loosening, etc.) and its correlation with clinical symptoms should be closely observed. Any lesion causing symptoms here should be estimated when deciding the extent of surgical resection, including moderate expansion to both sides when decompressing the posterior edge of the vertebral body by bone cutting.
6.How to determine the primary and secondary relationship between cervical spondylosis and cervical spinal stenosis The main disorders that can be easily confused with cervical spondylosis are: cervical spinal stenosis, cervicolumbar syndrome, lateral sclerosis of the spinal cord and spinal cavernous disease. The latter two disorders can be easily excluded due to the popularity of MR examinations, while cervicolumbar syndrome, which involves both the cervical and lumbar spine and causes compression of the rigid bursa, can also be easily diagnosed. Only cervical spinal stenosis and cervical spondylosis are most likely to be confused in the determination of the two, thus affecting the treatment, including the choice of surgical approach and procedure.
Cervical spinal stenosis itself is both an independent disease and the anatomical basis for the pathogenesis of cervical spondylosis, and the two are “homologous” in nature; therefore, it is often confusing to determine which one is the primary. In the authors’ opinion, the priority of the two should be determined whenever possible, as it is directly related to treatment and prognostic assessment. For the diagnosis of spinal stenosis, in addition to the clinical symptoms, it is more important to find out whether sensory or motor disorders are predominant at the time of onset; where sensory disorders are predominant, cervical spinal stenosis is the most common cause, and cervical posterior decompression should be performed. Of course, in late severe cases, it is difficult to confirm the diagnosis because of the confusion of symptoms, and the anterior and posterior approaches should be performed together (or successively) at this time.
7, attention to the shoulder and neck “nerve endings – muscle fiber weaving” is mainly seen in cases of cervical spondylosis who have done massage or pushing and moving techniques. This group of symptoms not only affects the efficacy of non-surgical treatment, but also constitutes a negative factor to the overall efficacy of anterior cervical decompression and fixation. After radical anterior cervical decompression, spinal cord and spinal nerve root symptoms tend to subside or diminish, while shoulder and back symptoms sometimes become prominent. The main reason for this is that push and pull, especially after heavy manipulation, can easily cause tearing, edema and oozing of local muscle fiber tissue; later on, adhesions and scarring can develop to form sustainable local symptoms; at this time, it is more difficult to deal with, especially for those with long duration of disease. Anyone with a history of tui na should be explained to the patient before surgery. Physiotherapy and acupuncture are effective for this disease, and because of its extensive damage surface, myofiber release should not be used unless it is very necessary.
II. Issues related to the treatment of cervical spondylosis
1, the basic principles of cervical spondylosis treatment is still mainly non-surgical treatment, of which more than 95% of cases have curative effect; only 2-5% of cases really need surgery. The current trend of surgical indications is expanding year by year; however, it must be clear that surgical complications and sequelae can be as high as 10% or more, coupled with the increasing number of cases requiring revision surgery; therefore, strict surgical indications are still needed. After decades of clinical observation, the most effective non-surgical treatments include: good, physiological sleep and work positions, avoiding and reducing neck flexion activities; light weight (about 1.5 kg) continuous traction for 3~4 weeks; no smoking; neck circumference protection, avoiding hard braking and other trauma; no pushing and pushing; and neurotrophic and vasodilator drugs.
2.Minimally invasive incision (less invasive surgery) As the aesthetic concept of contemporary people is becoming more and more demanding, the transverse incision in line with the skin pattern of the neck is the most popular, with a length of about 2.5~3cm, which can clearly reveal the front of C2~C7 vertebrae and perform various surgical operations, including the placement of plates up to 76mm in length. This operation is not difficult due to the elasticity and high extension of the neck skin. The trick is to release the deep cervical fascia in place. The authors have operated on thousands of patients with cervical spondylosis, and this minimally invasive incision not only reveals the target range, the osteotomy and decompression are smooth, and there is no difficulty in the placement of cage, titanium mesh, artificial vertebrae and plates, etc.; and no intraoperative complications such as injury to the recurrent laryngeal nerve and blood vessels have occurred so far.
3, the choice of decompression surgery The choice of decompression surgery varies from person to person, just as the 18 weapons have their own preferences and habits. However, it should be clear: although the multi-use electric grinding drill is considered to be safe, it is time-consuming intraoperatively and still has a certain rate of accidental injury. The current decrease in the use of the circular saw is related to the fact that the circular cage has been used less frequently in recent years; in fact, circular saw decompression should be considered one of the safest techniques for anterior cervical decompression. The bone chisel is still in use, as its depth is not easy to grasp and needs to be used with a scraper. Gun forceps are only used for anterior vertebral osteotomy and subtotal vertebral body resection, when involving the spinal canal, do not insert deep to prevent accidental injury to the spinal cord. Long years in the orthopedic front-line workers will feel that different angles of large and small scrapers are the best tools for cervical interbody osteotomy and decompression, and the authors are happy to use them, and have the effect of submerged osteotomy and decompression; however, the operation must hold the key with both hands, using the principle of lever mechanics to remove the compressive bone, and do not bounce to cause accidental injury.
4, the choice of internal fixation implants Current debate is more, in recent years, due to the progress of material science, elastic modulus between cortical bone and cancellous bone peek (polyether ether ketone) material designed for a variety of cage has been used in cervical surgery, and recognized by everyone. Components made of titanium and biodegradable carbon fibers are also still in use. Since internal fixation not only replaces diseased tissue, but is more important for restoration of vertebral segment height, canal sagittal expansion and stability. Therefore, artificial vertebral bodies, superimposed cages and titanium mesh can be chosen as appropriate. However, whatever implant is chosen, stability and effectiveness are preferred. The authors also recommend that the filling bone should be taken from the cervical vertebral segment with local excision of the bone tissue (including bone flab and cartilage tissue, etc.); the authors have done experimental studies to prove that the cartilage tissue of the vertebral segment has osteogenic effect similar to that of cortical bone. The round Cage is rarely used because of the fear of sinking, but if the anterior edge of the Cage is placed parallel to the bone cortex at the anterior edge of the vertebral body, this undesirable effect can be completely eliminated. On the contrary, titanium mesh has a higher probability of sinking in the middle of the vertebral body; therefore, titanium mesh is suitable for cervical fractures and should not be used for patients with cervical spondylosis.
The authors have performed thousands of anterior cervical decompressions in the past thirty years and have not experienced complications such as esophageal, tracheal and vascular injuries; one of the important reasons is that I never use automatic cervical spine braces to prevent injuries to the esophagus and trachea due to persistent compressive stress, or to cause local tissue edema and brittleness, which can be a trigger for esophageal fistula after surgery. Since such cases occur clinically and the consequences are serious, the authors emphasize that unless there is a lack of manpower in wartime or natural disasters, it is appropriate to use them at your discretion and to insist on unassisted pulling in general. As the assistant has tension and relaxation in the pulling process will not form continuous compression of the mediastinal tissue, thus avoiding many adverse consequences.
This is especially important for patients with severe cervical spondylosis. Supination and extension, especially under general anesthesia, can easily cause substantial damage to the spinal cord due to the invagination of the ligamentum flavum posterior to the spinal canal, or even complete paralysis that cannot be reversed; such cases are not rare clinically. Therefore, the authors suggest that for any patient undergoing cervical spine surgery, the maximum limit of the patient’s head and neck tilting should be detected preoperatively with the participation of anesthesiologists to ensure intraoperative tracheal intubation and safety during surgery.
7, the application of artificial discs and intervertebral joints As early as more than 20 years ago, the authors found that the adjacent vertebral segments are prone to degeneration after fusion and proposed the design of intervertebral artificial joints and artificial discs, and used in more than 100 clinical cases. In the long-term observation, it was proved that although this design can slow down the degeneration process of the adjacent vertebral segment, there are some cases in which the metal fatigue (NT-Z memory alloy) and fracture in the posterior part of the joint affect the long-term outcome. With the current development of material science, we will have new designs. In recent years, there has also been a controversial surge in functional reconstructive vertebral implants abroad to slow down the degenerative process of adjacent vertebral segments. However, due to the dramatic increase in medical costs (about 3-4 times), it has become a hot topic among clinicians, patients, insurance companies and medical device manufacturers, and the AAOS Annual Meeting 2008 has fully reflected the many focal points of this highly relevant clinical frontier from different perspectives.