Evaluation of Surgical Management of Spondylolithesis in Osteoporotic patients

DISCUSSION

Spondylolisthesis is the slippage of one vertebral body in respect to the adjacent vertebral body causing mechanical or radicular symptoms or pain. It can be due to congenital, acquired or idiopathic causes. Spondylolisthesis is graded based on the degree of slippage of one vertebral body on the adjacent vertebral body⁶_.

Degenerative spondylolisthesis predominately occurs in adults and is more common in females than males with increased risk

in the obese. Grade I spondylolisthesis accounts for 75% of all cases. Spondylolisthesis most commonly occurs at the L5-S1

level with anterior translation of the L5 vertebral body on the S1 vertebral body. The L4-5 level is the second mose common location for Spondylolisthesis.

Symptoms can range in severity from non-existent to a loss of urination and bowel movement control in more severe cases.

In most cases non-surgical treatment is successful in relieving the patient’s pain, but if not surgery may be considered²².

In our study medical treatement was tried for at least 1 month in every cases and surgical intervention was done only after failure of medical treatement.

A posterior fusion with pedicle screw instrumentation is generally considered the gold standard form of lumbar spinal fusion²³.

Our study showed different types of posterior fusion.

Okuda et al. examined the surgical outcomes of posterior lumbar interbody fusion in patients who were younger and older than 70 years and found that patients older than 70 years had a higher rate of delayed union than did younger patients, but the overall rate of fusion was not statistically different. Patients who have undergone appropriate screening and workup for osteoporosis and are considering spine surgery should be counseled preoperatively on the risk of delayed fusion. It is also important to note that a direct link between osteoporosis and worse clinical outcomes and a correlation between clinical outcomes and decreased rates of radiographic fusion or loss of deformity correction have not been definitively proven⁹_.

In our study all patient have been subjected to DEXA scan to  detect osteoporosis in elders  specially females.

At the 2000 National Institutes of Health (NIH) Consensus Conference, osteoporosis was defined as a skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture¹_.

Occurrence and development of osteoporosis is a painless process. The set of degenerative changes appearing in aging spines in symptomatic patients, are identical to those with degenerated spines in asymptomatic subjects⁵_.

However, profound inactivity from a progressive and painful degeneration and destabilization of the spine coupled with the pain and inactivity from a symptomatic osteoporotic compression fracture can lead to a downward spiral of further bone loss and degeneration, more vertebral fractures, more pain and inactivity Zygapophysial joint osteoarthritis, degenerative changes in the discs, intervertebral space narrowing, and bony remodeling due to osteoporosis they are all degenerative changes associated with the aging of the spine⁵_.

These degenerative changes induce to deformities in the vertebrae, modifications and alterations in the stress distribution and the normal alienation of the spine accountable for the occurrence of degenerative segmental instabilities and subluxations like spinal stenosis, degenerative spondylolisthesis, and scoliosis. Degenerative spondylolisthesis and scoliosis are generally asymptomatic, but they can associate or aggravate a preexisting symptomatic spinal stenosis¹⁰_.

In our study patients with back pain and sciatica have been subjected to complete history taking and full general and neurological examination and radiological evaluation to detect bone abnormalities.

The majority of patients with degenerative spondylolisthesis will respond well to non-operative treatment, including NSAIDs, epidural injections, and lumbar flexibility and strengthening exercises. Patients with severe or persistent symptoms that interfere significantly with quality of life, or those with neurological deficit, may benefit from surgical decompression removing all bony and soft-tissue pressure on their neural elements.There is no universal agreement regarding the optimal surgical approach for the treatment of degenerative spondylolisthesis: current controversies include the need for an additional fusion (either posterolateral or interbody fusion) with or without instrumentation, compared with decompression only.

In our study posterior decompression was associated with instrumental fixation.

A recent study showed that, in patients with lumbar disk herniation, a delay of ≥12 weeks in time to surgery was more likely to result in greater pain at 6 months postoperatively, suggesting that delays in surgical treatment of patients with this and other degenerative lumbar conditions may predispose patients to worse clinical outcomes¹¹_.

Therefore, postponing elective spine procedures to allow for medical optimization of osteoporosis is controversial, and no consensus on this topic currently exists. Improvements in BMD occur over relatively longer periods of time and, in many patients, it is not reasonable to consider waiting until evidence of improved BMD has been confirmed on DEXA.

In our study surgical intervention has not been postponed after failure of medical treatement even  with poor BMD.

Specific affected levels should be identified and treated, and appropriate sagittal alignment should be restored, although evidence suggests that larger deformity correction in older patients (average age, ≥60 years) increases the risk of junctional kyphosis¹³_.

In our study the affected level was properly identified and appropriate sagittal alignment was restored .

The trajectory of the sacral screws should ideally be toward the promontory to improve purchase because screws inserted in this tricortical manner have been shown to have twice the insertional torque of bicortical screws¹²_.

In our study all patient with sacral fixation all trajectories were towards the promontory.Augmentation of pedicle screws with polymethyl methacrylate (PMMA) or calcium phosphate as a method of improving fixation strength has been studied extensively^14,15,16,17_.

Previous clinical studies have reported peri/postoperative complication incidences when operating on patients with adult spinal deformity and poor bone quality of up to or more than 40%. However, to the present day there are still very few studies evaluating the incidence and specific types of complications associated with its surgical treatment.

In our study operative complications were about 20% and post operative complications were about 20% also.

Amendola et al. published a study of 21 patients who had a poor bone stock condition due to osteoporosis or tumor and who underwent posterior stabilization by fenestrated pedicle screws and PMMA All patients were clinically and radiographically followed up for a mean of 36 months. No case of loosening was recorded after a mean follow-up of 36 months. augmentation¹⁸_..

In our study the combination between transpedicular screws and bone cement provided a safe and effective method of fixation.

Carreon et al. reported the results of a study examining the rate of perioperative medical complications in 98 elderly patients who underwent posterior decompression and lumbar arthrodesis with instrumentation to treat degenerative disorders of the spine¹⁹_.

The mean age was 72 years (65 to 84 years). Perioperative complications occurred in 78 patients (79%). Twenty-one patients (22%) had at least one major complication including 2 deaths both from postoperative wound sepsis, and 69 had at least one minor complication (70%). The most frequent complications were wound infection (10%) among the major complications and urinary tract infection (34%) among the minor complications. A greater blood loss, a prolonged operative time, a greater number of levels fused, and an older age, all were associated with an increased occurrence of perioperative complications. The presence, type, or number of preoperative medical conditions was not related to the occurrence of complications. This finding is similar to that of Benz et al., who reported that the presence of associated medical diseases did not affect the incidence of postoperative complications²⁰_.

However, other studies showed that the prevalence of postoperative morbidity increased as the number of premorbid diseases increased²¹_.

In our study 30 cases  of spondylolithesis with osteoporosis were done at al azhar university hospitals over 2 years; the Transpedicular Fixation after injection of bone cement in the track (60.0%), Transpedicular Fixation with canulated screws & bone cement (20.0%), Transpedicular Fixation (13.3%), and Lumber cage (6.7%) of Surgical management

According to the financial aspects of the patients using ordinary pedicular screws after bone cement injecrtion in the track provided an effective alternative  to the cannulated screws with such suitable cost. The results show that the percentage  of improvement of patient complain as regard low back pain: fair (33.3%),good (46.7%),excellent (13.3%), as regard sciatica: fair (6.7%),good (33.3%),excellent(60.0% , as regard claudication: good (50.0%), excellent (50.0%), as regard motor: fair (25.0%), good (25.0%) , excellent (50.0%) , as regard sensory Good (66.7%), excellent (33.3%),and as regard sphincter : good (50.0%),excellent (50.0%) .

CONCLUSION

In patients with osteoporosis,the DEXA scan is the most effective method to detect these patients .We recommend DEXA scan in all patients above 50 years old specially females .Surgical treatement with transpedicular screw fixation combined with use of bone cement is safe and effective method for treatement of osteoprotic patient with spondylolithesis not responding to medical treatement .