Comparison of sagittal vertical axis and decompression on the clinical outcome of cervical spondylotic myelopathy.

OBJECTIVE: Decompression and cervical balance are major goals in the surgical treatment of cervical spondylotic myelopathy (CSM). Cervical balance is assumed to be a key factor for neurological recovery and pain reduction. Surgical reduction of C2-7 sagittal vertical axis (SVA) correlates with clinical improvement. However, it remains unclear, how much or even if correction is necessary for clinical improvement as long as surgery results in successful decompression. We aim to evaluate the role of radiological cervical balance parameter on the short-term course of CSM. METHODS: This is a retrospective study with prospectively collected data of 90 patients. The authors identified 45 patients suffering from CSM that underwent decompressive surgery and instrumentation and showed an increased C2-7 sagittal vertical axis (SVA) after surgery. 45 consecutive patients with a decreased C2-7 SVA were selected as a control group. RESULTS: Surgery improved the clinical outcome of both groups significantly. No differences could be seen comparing neck pain and neurological improvement between both groups. An increased C2-7 SVA did not correlate with an inferior clinical outcome. T1-slope correlated with the Cobb-angle. CONCLUSIONS: Decompression and stabilization appear to be key elements of surgical treatment of CSM. In short terms, clinical improvement does not appear to affect patients negatively who show a larger C2-7 SVA after surgery. Optimal C2-7 SVA and necessity for a specific C2-7 correction is unclear. The term "balance" remains a complex entity without clear definition.

The influence of sagittal profile alteration and final lordosis on the clinical outcome of cervical spondylotic myelopathy. A Delta-Omega-analysis.

PURPOSE: Decompression and maintaining or restoring a cervical lordosis are major goals in the surgical treatment of cervical spondylotic myelopathy (CSM). Numerous studies support the assumption that cervical lordosis is a key factor for neurological recovery and pain reduction. However, even kyphotic patients can be asymptomatic. The balance of the spine is subject of an increasing number of publications. The main purpose of the study was to evaluate the validity of lordotic alignment on the course of CSM and to set this parameter in context with well-validated tools, namely the modified Japanese Orthopaedic Association scoring system (mJOAS) and the visual analogue scale (VAS), to predict and measure the clinical outcome after surgery. METHODS: This is a retrospective study with prospectively collected data of a heterogeneous cohort. The authors analyzed the records of 102 patients suffering from CSM that underwent decompressive surgery and instrumentation. Clinical outcome was assessed by using the mJOAS, VAS and Odom's criteria. The radiological analysis involved comparison of pre- and postoperative radiographs. The patients were divided into subgroups to be able to compare the influence of various amounts of correction (3 Delta-groups: <0°, 1-7° and ≥8°) and final lordosis (4 Omega-groups: 0-7°, 8-14°, 15-21°, ≥22°). RESULTS: 219 levels were fused in 102 patients. Surgery improved the clinical outcome of all groups significantly. A lordotic profile was achieved in all analyzed groups. Patients that showed small lordosis after surgery (<8°) did not have an inferior clinical outcome compared to patients with larger cervical lordosis (>14°). The comparison of Odom's criteria showed that preoperatively kyphotic patients benefitted more from surgery than lordotic patients (p = 0.029), but no differences could be seen comparing neck pain and neurological improvement. The improvement of pain and neurological impairment measured by VAS and mJOAS supports the statistical impact and validity of the data despite comparatively small numbers of patients. The lack of postoperative kyphosis is a major limitation of the study to encompass the impact of sagittal alignment on clinical outcome. CONCLUSIONS: Decompression and stabilization appear to be key elements of surgical treatment of CSM. While the achievement of cervical lordosis remains a major goal of surgery, clinical improvement is not hindered in patients who show small lordosis. However, kyphosis should be eliminated in symptomatic patients. The terms "balance" and "physiologic lordosis" remain complex entities without clear definition. To check the results of our study controlled randomized trials to validate and determine the exact role of cervical balance on the course of CSM would be helpful.

Transient sacroiliac joint-related pain is a common problem following lumbar decompressive surgery without instrumentation.

OBJECTIVE: Patients with lumbar stenosis profit substantially from decompressive surgery. The change of body position and walking behaviour after successful surgery might lead to changed force effects on the entire spine and on the sacroiliac joint (SIJ). We analyzed the incidence of postoperative SIJ-related pain. METHODS: The authors analyzed the records of 100 consecutive patients from three institutions, who underwent decompressive surgery without instrumentation. The diagnosis of SIJ-related pain was confirmed by periarticular infiltration. The radiological changes of the sacroiliac joint were assessed in plain radiographs in both groups: patients with SIJ pain (group 1) and patients without SIJ pain (group 2) after surgery. RESULTS: 22 patients required medical attention due to SIJ-related pain after surgery. While the walking distance increased substantially in both groups without difference (p=0.150), the analysis of overall satisfaction favoured group 2 (p=0.047). Female patients suffered more from SIJ pain after surgery (p=0.036). Age, severity of radiological changes or number of operated segments appeared not to trigger SIJ-related pain. CONCLUSION: The adaptation of a changed body posture and gait could lead to transient overload of the SIJ and surrounding myofascial structures. The patients should be informed about this possible condition to avoid uncertainty, discontent, unnecessary diagnostics and to induce a quick, specific treatment. Non-diagnosed sacroiliac joint-related pain could be a possible, but reversible reason for the diagnosis of a "failed-back-surgery".

Application of titanium and polyetheretherketone cages in the treatment of pyogenic spondylodiscitis.

OBJECTIVE: Surgical treatment of a pyogenic spondylodiscitis (PSD) involves a fixation and debridement of the affected segment combined with a specific antibiotic therapy. To achieve a proper stability and to avoid pseudarthrosis and kyphotic malposition many surgeons favour the interposition of an anterior graft. Besides autologous bone grafts titanium (TTN) cages have gained acceptance in the treatment of PSD. Polyetheretherketone (PEEK) cages have a more favourable modulus of elasticity than TTN. We compared both cage types. Primary endpoints were the rate of reinfection and radiological results. METHODS: From 2004 to 2013 51 patients underwent surgery for PSD with fixation and TTN or PEEK cage-implantation. While lumbar patients underwent a partial discectomy by the posterior approach, discs of the cervical and thoracic patients had been totally removed from anterior. Clinical and radiological parameters were assessed in 37 eligible patients after a mean of 20.4 months. 21 patients received a PEEK- and 16 patients a TTN-cage. RESULTS: A reinfection after surgery and 3 months of antibiotic therapy was not observed. Solid arthrodesis was found in 90.5% of the PEEK-group and 100% of the TTN-group. A segmental correction could be achieved in both groups. Nonetheless, a cage subsidence was observed in 70.3% of all cases. Comparison of radiological results revealed no differences between both groups. CONCLUSIONS: A debridement and fixation with anterior column support in combination with an antibiotic therapy appear to be the key points for successful treatment of PSD. The application of TTN- or PEEK-cages does not appear to influence the radiological outcome or risk of reinfection, neither does the extent of disc removal in this clinical subset.

Single- and multi-level anterior decompression and fusion for cervical spondylotic myelopathy--a long term follow-up with a minimum of 5 years.

OBJECTIVE: Cervical spondylotic myelopathy (CSM) is a common disease leading to significant neurological disability. We compared patients suffering from a single- and a multi-level pathology to analyze the influence of the natural course of the disease on the long-term outcome after surgery. METHODS: We analyzed the records of 52 patients with CSM after surgery. The neurological status of the patients was assessed by the modified Japanese Orthopaedic Association Scale (mJOAS). X-rays were conducted before and after surgery. RESULTS: 52 patients were treated by a single-level (n=27) or a multi-level approach (n=25) more than 5 years ago. A significant improvement of the neurological status could be seen even 5 years or more after surgery in both groups without differences. After one year no further improvement could be observed. In the single-level group a trend to a subsequent loss of lordotic correction could be seen. Anterior plates were only used in the multi-level group. CONCLUSION: The anterior approach is an effective procedure to improve the symptoms of a CSM for many years. The risk of a multi-level pathology does not appear to exceed the risks of a single-level pathology concerning clinical long-term outcome after surgery. The clinical success is not hindered by a loss of correction in this specific setting.

Anterior cervical discectomy and fusion: comparison of titanium and polyetheretherketone cages.

BACKGROUND: Titanium (TTN) cages have a higher modulus of elasticity when compared with polyetheretherketone (PEEK) cages. This suggests that TTN-cages could show more frequent cage subsidence after anterior cervical discectomy and fusion (ACDF) and therefore might lead to a higher loss of correction. We compared the long term results of stand-alone PEEK- and TTN-cages in a comparable patient collective that was operated under identical operative settings. METHODS: From 2002 to 2007 154 patients underwent single-level ACDF for degenerative disc disease (DDD). Clinical and radiological outcome were assessed in 86 eligible patients after a mean of 28.4 months. 44 patients received a TTN- and 42 patients a PEEK-cage. RESULTS: Solid arthrodesis was found in 93.2% of the TTN-group and 88.1% of the PEEK-group. Cage subsidence was observed in 20.5% of the TTN- and 14.3% of the PEEK-group. A significant segmental lordotic correction was achieved by both cage-types. Even though a loss of correction was found at the last follow-up in both groups, it did not reach the level of statistical significance. Statistical analysis of these results revealed no differences between the TTN- and PEEK-group.When assessed with the neck disability index (NDI), the visual analogue scale (VAS) of neck and arm pain and Odom's criteria the clinical data showed no significant differences between the groups. CONCLUSIONS: Clinical and radiological outcomes of ACDF with TTN- or PEEK-cages do not appear to be influenced by the chosen synthetic graft. The modulus of elasticity represents only one of many physical properties of a cage. Design, shape, size, surface architecture of a cage as well as bone density, endplate preparation and applied distraction during surgery need to be considered as further important factors.

The analysis of segmental mobility with different lumbar radiographs in symptomatic patients with a spondylolisthesis.

PURPOSE: Lumbar flexion-extension radiographs in standing position (SFE) are the most commonly used imaging method to evaluate segmental mobility. Many surgeons use SFE to disclose abnormal vertebral motion and base their decision for surgical fusion on its results. We tested the hypothesis that imaging in standing and recumbent position (SRP) reveals a higher sagittal translation (ST) and sagittal rotation (SR) in symptomatic patients than with SFE. MATERIALS AND METHODS: We analysed images of 100 symptomatic patients with a low-grade spondylolisthesis that underwent surgical fusion. To determine the ST and SR in SRP, we compared the images taken in the recumbent position in the CT with images taken in the standing position during the routine plain radiography. RESULTS: The measurement of ST revealed an absolute value of 2.3 ± 1.5 mm in SFE and 4.0 ± 2.0 mm in SRP and differed significantly (p = 0.001). The analysis of the relative value showed an ST of 5.9 ± 3.9% in SFE and 7.8 ± 5.4% in SRP (p = 0.008). The assessment of ST in flexion and in a recumbent position (FRP) revealed the highest ST (4.6 ± 2.5 mm or 9.2 ± 5.7%). Comparison of SR showed the highest rotation in SFE (6.1° ± 3.8°), however, compared to SRP (5.4° ± 3.3°), it missed the level of significance (p = 0.051). CONCLUSIONS: For evaluation of ST in symptomatic patients with spondylolisthesis SRP appears to be more suitable than SFE, while a pathological SR is better revealed in SFE. The analysis of SRP might offer a complementary method to detect or exclude pathological mobility in more cases.

Polymethylmethacrylate-assisted ventral discectomy: rate of pseudarthrosis and clinical outcome with a minimum follow-up of 5 years.

BACKGROUND: Polymethylmethacrylate (PMMA) assisted ventral discectomy has been criticized for high rates of graft migration and pseudarthrosis when compared with various other fusion procedures for the treatment of cervical degenerative disc disease (DDD), therefore rendering it not the preferred choice of treatment today. Recently however spine surgery has been developing towards preservation rather than restriction of motion, indicating that fusion might not be necessary for clinical success. This study presents a long term comparison of clinical and radiological data from patients with pseudarthrosis and solid arthrodesis after PMMA assisted ventral discectomy was performed. METHODS: From 1986 to 2004 416 patients underwent ventral discectomy and PMMA interposition for DDD. The clinical and radiological outcome was assessed for 50 of 127 eligible patients after a mean of 8.1 years. Based on postoperative radiographs the patients were dichotomized in those with a pseudarthrosis (group A) and those with solid arthrodesis (group B). RESULTS: Pseudarthrosis with movement of more than 2 of the operated segment was noted in 17 cases (group A). In 33 cases no movement of the vertebral segment could be detected (group B). The analysis of the clinical data assessed through the neck disability index (NDI), the visual analogue scale (VAS) of neck and arm pain and Odom's criteria did not show any significant differences between the groups.Patients from group B showed a trend to higher adjacent segment degeneration (ASD) than group A (p = 0.06). This correlated with the age of the patients. CONCLUSIONS: PMMA assisted discectomy shows a high rate of pseudarthrosis. But the clinical long-term success does not seem to be negatively affected by this.

Arachnoid cysts of the middle cranial fossa accompanied by subdural effusions--experience with 60 consecutive cases.

BACKGROUND: Subdural effusions (SDEs) can complicate arachnoid cysts of the middle cranial fossa (ACMFs). While there is a consensus that at least in adults asymptomatic ACMFs should not be operated, those with concomitant subdural and/or intracystic effusions are clinically apparent in the majority of cases and should be surgically treated. But it remains unclear, which surgical procedure is best. METHODS: Since 1980, 60 out of 343 patients with an ACMF presented with accompanying SDEs. Four categories of SDEs were differentiated radiologically. This collective was controlled in a follow-up study up to 60 months after conservative or operative treatment by clinical and radiological means. RESULTS: In 54 of the 60 patients, we saw an indication for surgical treatment. Twenty-nine patients received a burr hole, 13 cases were treated by craniotomy, seven by endoscopical means, three patients underwent shunting and two combined procedures. Six patients were treated conservatively. An excellent final clinical outcome was observed in 55 cases. While craniotomy succeeded best to reduce the cyst volume in postoperative CT, the final clinical outcome did not differ significantly compared with burr hole trepanation. CONCLUSIONS: Patients with small effusions can be treated conservatively in selected cases. Based on our experience, we prefer a differentiated therapy. As first procedure, burr hole and subdural drainage were performed, leaving the cyst alone, seeming sufficient for the majority of cases. Craniotomy or endoscopical means should be reserved as treatment of choice for special cases, depending on category and acuteness of SDE and size/localisation of the ACMF.

Comparison between anterior and posterior decompression with instrumentation for cervical spondylotic myelopathy: sagittal alignment and clinical outcome.

OBJECT: A variety of anterior, posterior, and combined approaches exist to decompress the spinal cord, restore sagittal alignment, and avoid kyphosis, but the optimal surgical strategy remains controversial. The authors compared the anterior and posterior approach used to treat multilevel cervical spondylotic myelopathy (CSM), focusing on sagittal alignment and clinical outcome. METHODS: The authors studied 48 patients with CSM who underwent multilevel decompressive surgery using an anterior or posterior approach with instrumentation (24 patients in each group), depending on preoperative sagittal alignment and direction of spinal cord compression. In the anterior group, a 1-2-level corpectomy was followed by placement of an expandable titanium cage. In the posterior group, a multilevel laminectomy and posterior instrumentation using lateral mass screws was performed. Postoperative radiography and clinical examinations were performed after 1 week, 12 months, and at last follow-up (range 15-112 months, mean 33 months). The radiological outcome was evaluated using measurement of the cervical and segmental lordosis. RESULTS: Both the posterior multilevel laminectomy (with instrumentation) and the anterior cervical corpectomy (with instrumentation) improved clinical outcome. The anterior group had a significantly lower preoperative cervical and segmental lordosis than the posterior group. The cervical and segmental lordosis improved in the anterior group by 8.8 and 6.2 degrees, respectively, and declined in the posterior group by 6.5 and 3.8 degrees, respectively. The loss of correction was higher in the anterior than in the posterior group (-2.0 vs -0.7 degrees, respectively) at last follow-up. CONCLUSIONS: These results demonstrate that both anterior and posterior decompression (with instrumentation) are effective procedures to improve the neurological outcome of patients with CSM. However, sagittal alignment may be better restored using the anterior approach, but harbors a higher rate of loss of correction. In cases involving a preexisting cervical kyphosis, an anterior or combined approach might be necessary to restore the lordotic cervical alignment.