Kyphectomy and interbody fixation using lag screws in a child with myelomeningocele kyphosis: a technical case report.

A 5-year-old boy had a thoracolumbar-level MMC that had been repaired at the day after birth and kyphotic deformity got worse as he grew. He complained of discomfort about not being able to take a supine posture and decided to perform surgery for kyphosis. In our case, surgical correction is offered to stop the deformity progression, manage the associated pain, and finally to gain sitting and supine posture. We report the surgical procedure with 4 levels of en bloc kyphectomy and using the lag screws. Especially when lag screws are used, several complications including posterior instrumentation failure, hardware prominence and wound break down can be solved by removing the implants after bone fusion has been achieved.

S2 alar iliac screw placement under robotic guidance for adult spinal deformity patients: technical note.

PURPOSE: S2 alar-iliac (S2AI) screws are generally placed using an open approach, but have recently been shown to be implantable using a minimally invasive approach. Nevertheless, optimal screw positioning, even when supported by fluoroscopic guidance, is challenging in the complex anatomy of the sacral-pelvic area. This work presents our novel technique of S2AI sacropelvic fixation procedures performed with robotic guidance. METHODS: This was a single-center, retrospective, mini case-series of adult spinal deformity patients in need of sacropelvic fixation as part of a longer thoraco-lumbar fusion. The surgeon drilled a pilot hole through a robotic guide and then inserted a K-wire. A Jamshidi needle was placed over the K-wire and used to advance the pilot hole anterolaterally. RESULTS: Medical charts of four 60-70 year-old patients, who underwent robotic-guided insertion of S2AI screws in a minimally invasive approach were reviewed. Follow-up ranged between 10 and 13 months. Post-operative CTs and X-rays showed all eight trajectories were fully within the bone and accurately placed. Average surgery time per patient was 13 min with 5.3 s of fluoroscopy per screw. No intra- or post-operative complications occurred. CONCLUSIONS: Robotic-guidance with a Jamshidi needle technique was a safe and effective means for implanting S2AI screws in a minimally invasive approach.

Long-term recurrence rates after the removal of spinal meningiomas in relation to Simpson grades.

PURPOSE: Simpson grade II removal (coagulation of the dural attachment after gross total removal) of spinal meningioma is considered an acceptable alternative, but increased recurrence after more than 10 years has been reported. More attention must be paid to the long-term surgical outcomes after Simpson grade II removal. METHODS: A retrospective review was performed for 20 patients (M:F = 5:15; age, 59 ± 9 years) with Simpson grade II removal (mean follow-up period, 12.9 years; range 10.0-17.5). Magnetic resonance (MR) imaging was conducted in 17 patients at 88 ± 52 months (range 12-157). During the same period, Simpson grade I removal (removal of the dural origin) was performed in 21 patients (follow-up, 89 ± 87 months; range 9-316). Radiological recurrence was defined as a visible tumor on a follow-up MR image, and clinical tumor recurrence was defined as the recurrence of symptoms. RESULTS: At the final follow-up, neurological symptoms had improved in 16/20 patients and remained stable in 4/20. A recurrent tumor was detected in one patient due to increased back pain at 92 months postoperative, but the symptom was stable without surgery until the last follow-up (124 months). The radiological and clinical recurrence-free survival periods were 150 ± 7 months (95 % CI 136-163) and 204 ± 6 months (95 % CI 193-215), respectively. There was no recurrence after Simpson grade I removal, whereas neurological deterioration occurred in two patients after surgery. CONCLUSIONS: Simpson grade II removal may be an alternative option if the risk of complications with Simpson grade I removal is expected to be high.

Facet joint changes after application of lumbar nonfusion dynamic stabilization.

OBJECTIVE The long-term effects on adjacent-segment pathology after nonfusion dynamic stabilization is unclear, and, in particular, changes at the adjacent facet joints have not been reported in a clinical study. This study aims to compare changes in the adjacent facet joints after lumbar spinal surgery. METHODS Patients who underwent monosegmental surgery at L4-5 with nonfusion dynamic stabilization using the Dynesys system (Dynesys group) or transforaminal lumbar interbody fusion with pedicle screw fixation (fusion group) were retrospectively compared. Facet joint degeneration was evaluated at each segment using the CT grading system. RESULTS The Dynesys group included 15 patients, while the fusion group included 22 patients. The preoperative facet joint degeneration CT grades were not different between the 2 groups. Compared with the preoperative CT grades, 1 side of the facet joints at L3-4 and L4-5 had significantly more degeneration in the Dynesys group. In the fusion group, significant facet joint degeneration developed on both sides at L2-3, L3-4, and L5-S1. The subjective back and leg pain scores were not different between the 2 groups during follow-up, but functional outcome based on the Oswestry Disability Index improved less in the fusion group than in the Dynesys group. CONCLUSIONS Nonfusion dynamic stabilization using the Dynesys system had a greater preventative effect on facet joint degeneration in comparison with that obtained using fusion surgery. The Dynesys system, however, resulted in facet joint degeneration at the instrumented segments and above. An improved physiological nonfusion dynamic stabilization system for lumbar spinal surgery should be developed.

Dynamic stabilization using the Dynesys system versus posterior lumbar interbody fusion for the treatment of degenerative lumbar spinal disease: a clinical and radiological outcomes-based meta-analysis.

OBJECTIVE The Dynesys, a pedicle-based dynamic stabilization (PDS) system, was introduced to overcome the drawbacks of fusion procedures. Nevertheless, the theoretical advantages of PDS over fusion have not been clearly confirmed. The aim of this study was to compare clinical and radiological outcomes of patients who underwent PDS using the Dynesys system with those who underwent posterior lumbar interbody fusion (PLIF). METHODS The authors searched PubMed, Embase, Web of Science, and the Cochrane Database. Studies that reported outcomes of patients who underwent PDS or PLIF for the treatment of degenerative lumbar spinal disease were included. The primary efficacy end points were perioperative outcomes. The secondary efficacy end points were changes in the Oswestry Disability Index (ODI) and back and leg pain visual analog scale (VAS) scores and in range of motion (ROM) at the treated and adjacent segments. A meta-analysis was performed to calculate weighted mean differences (WMDs), 95% confidence intervals, Q statistics, and I(2) values. Forest plots were constructed for each analysis group. RESULTS Of the 274 retrieved articles, 7 (which involved 506 participants [Dynesys, 250; PLIF, 256]) met the inclusion criteria. The Dynesys group showed a competitive advantage in mean surgery duration (20.73 minutes, 95% CI 8.76-32.70 minutes), blood loss (81.87 ml, 95% CI 45.11-118.63 ml), and length of hospital stay (1.32 days, 95% CI 0.23-2.41 days). Both the Dynesys and PLIF groups experienced improved ODI and VAS scores after 2 years of follow-up. Regarding the ODI and VAS scores, no statistically significant difference was noted according to surgical procedure (ODI: WMD 0.12, 95% CI -3.48 to 3.72; back pain VAS score: WMD -0.15; 95% CI -0.56 to 0.26; leg pain VAS score: WMD -0.07; 95% CI -0.47 to 0.32). The mean ROM at the adjacent segment increased in both groups, and there was no substantial difference between them (WMD 1.13; 95% CI -0.33 to 2.59). Although the United States is the biggest market for Dynesys, no eligible study from the United States was found, and 4 of 8 enrolled studies were performed in China. The results must be interpreted with caution because of publication bias. During Dynesys implantation, surgeons have to decide the length of the spacer and cord pretension. These values are debatable and can vary according to the surgeon's experience and the patient's condition. Differences between the surgical procedures were not considered in this study. CONCLUSIONS Fusion still remains the method of choice for advanced degeneration and gross instability. However, spinal degenerative disease with or without Grade I spondylolisthesis, particularly in patients who require a quicker recovery, will likely constitute the main indication for PDS using the Dynesys system.

Which one is a valuable surrogate for predicting survival between Tomita and Tokuhashi scores in patients with spinal metastases? A meta-analysis for diagnostic test accuracy and individual participant data analysis.

This study is to estimate the diagnostic accuracy of Tokuhashi and Tomita scores that assures 6-month predicting survival regarded as a standard of surgical treatment. We searched PubMed, EMBASE, European PubMed central, and the Cochrane library for papers about the sensitivities and specificities of the Tokuhashi and/or Tomita scores to estimate predicting survival. Studies with cut-off values of ≥9 for Tokuhashi and ≤7 for Tomita scores based on prior studies were enrolled. Sensitivity, specificity, diagnostic odds ratio (DOR), area under the curve (AUC), and the best cut-off value were calculated via meta-analysis and individual participant data analysis. Finally, 22 studies were enrolled in the meta-analysis, and 1095 patients from 8 studies were included in the individual data analysis. In the meta-analysis, the pooled sensitivity/specificity/DOR for 6-month survival were 57.7 %/76.6 %/4.70 for the Tokuhashi score and 81.8 %/47.8 %/4.93 for Tomita score. The AUC of summary receiver operating characteristic plots was 0.748 for the Tokuhashi score and 0.714 for the Tomita score. Although Tokuhashi score was more accurate than Tomita score slightly, both showed low accuracy to predict 6 months residual survival. Moreover, the best cut-off values of Tokuhashi and Tomita scores were 8 and 6, not 9 and 7, for predicting 6-month survival, respectively. Estimation of 6-month predicting survival to decide surgery in patients with spinal metastasis is quite limited by using Tokuhashi and Tomita scores alone. Tokuhashi and Tomita scores could be incorporated as part of a multidisciplinary approach or perhaps interpreted in the context of a multidisciplinary approach.

Correlation between cervical lordosis and adjacent segment pathology after anterior cervical spinal surgery.

PURPOSE: To evaluate the incidence and risk factors for adjacent segment pathology (ASP) after anterior cervical spinal surgery. METHODS: Fourteen patients (12 male, mean age 47.1 years) who underwent single-level cervical disk arthroplasty (CDA group) and 28 case-matched patients (24 male, mean age 53.6 years) who underwent single-level anterior cervical discectomy and fusion (ACDF group) were included. Presence of radiologic ASP (RASP) was based on observed changes in anterior osteophytes, disks, and calcification of the anterior longitudinal ligament on lateral radiographs. RESULTS: The mean follow-up period was 43.4 months in the CDA group and 44.6 months in the ACDF group. At final follow-up, ASP was observed in 5 (35.7%) CDA patients and 16 (57.1%) ACDF patients (p = 0.272). The interval between surgery and ASP development was 33.8 months in the CDA group and 16.3 months in the ACDF group (p = 0.046). The ASP risk factor analysis indicated postoperative cervical angle at C3-7 being more lordotic in non-ASP patients in both groups. Restoration of lordosis occurred in the CDA group regardless of the presence of ASP, but heterotopic ossification development was associated with the presence of ASP in the CDA group. And the CDA group had significantly greater clinical improvements than those in the ACDF group when ASP was present. CONCLUSION: In both CDA and ACDF patients, RASP developed, but CDA was associated with a delay in ASP development. A good clinical outcome was expected in CDA group, even when ASP developed. Restoration of cervical lordosis was an important factor in anterior cervical spine surgery.

A longitudinal study to assess the volumetric growth rate of spinal intradural extramedullary tumour diagnosed with schwannoma by magnetic resonance imaging.

PURPOSE: Spinal intradural extramedullary (IDEM) schwannoma diagnosed by magnetic resonance (MR) imaging is sometimes detected incidentally. Because the natural history of spinal IDEM schwannoma has not been established well, questions remain regarding whether small and asymptomatic tumour has to be removed. We aimed to assess the natural history of spinal schwannoma diagnosed by MR imaging using an accurate and reliable method. METHODS: All patients who were diagnosed with spinal IDEM schwannoma by MR imaging and did not undergo surgical resection immediately were recruited. A number of 56 tumours were enrolled finally. Tumour volume was measured using the volume quantification method from the baseline through the final follow-up. Receiver operating characteristics plots were used to define cut-off value of discrimination. RESULTS: The probable schwannoma grew 5.45% [median value of volumetric growth rate (VGR); interquartile range 0.14-14.19] annually with a mean surveillance interval of 43.6 months. Of the 56 tumours, some tumours kept growing rapidly and the others did not. The median annual VGR of the growing and stable probable schwannomas was 13.02 and -0.09%, respectively (P<0.001). They can be roughly divided by 2.5% of the annual VGR and usually maintained each growth pattern and the cross-over rate to growth pattern was 15.6%. CONCLUSIONS: Spinal probable IDEM schwannoma grew 5.45% of the tumour volume annually and can be divided into growing and stable tumours. The tumour that grows≥2.5% of volume per year needs a careful inspection because it may be not benign schwannoma and keep growing continuously.

Subsidence as of 12 months after single-level anterior cervical inter-body fusion. Is it related to clinical outcomes?

BACKGROUND: Subsidence is a frequent phenomenon in the interbody fusion process in patients with anterior cervical discectomy and fusion (ACDF). There is little evidence of whether subsidence in the cervical spine has any impact on clinical outcomes. OBJECTIVES: The purpose of this study is to investigate the correlation of subsidence and clinical outcomes after ACDF and to consider reasons subsidence might not cause unfavorable clinical outcomes. METHODS: A total of 158 consecutive patients who underwent single-level ACDF were included. The patients were divided into a subsidence group (S-group) and a no subsidence group (N-group), with subsidence defined as a decrease by ≥3 mm in total intervertebral height (TIH). We analyzed outcomes resulting from subsidence, particularly focusing on clinical outcomes and subsequent global and segmental kyphosis using a repeated measure analysis of variance (RM-ANOVA). RESULTS: Subsidence occurred in 74 patients (46.8%) as of a 12-month follow-up. The S-group included 58.6% with a stand-alone cage for interbody fusion (p = 0.002). Clinical outcomes improved significantly over time (neck pain, RM-ANOVA: F(1.3, 205) = 125.1, p < 0.001; arm pain, RM-ANOVA: F(1.3, 203) = 290.8, p < 0.001). There was no significant difference in interaction with subsidence and clinical outcomes between the S- and N-group (neck pain, RM-ANOVA: F(2,153) = 1.04, p = 0.356, partial η(2) = 0.229; arm pain, RM-ANOVA: F(2,153) = 0.56, p = 0.571, partial η(2) = 0.142). Segmental angle increased in both groups over time and showed a statistically significant difference between the S- and N-groups (RM-ANOVA: F(3,143) = 6.148, p = 0.001, partial η(2) = 0.959). Although, global cervical angle decreased generally and displayed no statically significant difference between the S- and N-group (RM-ANOVA: F(3,119) = 2.361, p = 0.075, partial η(2) = 0.056). CONCLUSIONS: Radiographic subsidence after ACDF occurred in 46.8% patients as of 12 months after the single-level ACDF. The lack of correlation between bad clinical outcome and radiographic subsidence may be due to segmental kyphosis, preserved posterior height, and maintaining the global cervical angle.

Segmental kyphosis after cervical interbody fusion with stand-alone polyetheretherketone (PEEK) cages: a comparative study on 2 different PEEK cages.

STUDY DESIGN: Retrospective comparative study. OBJECTIVE: Two polyetheretherketone (PEEK) cages of different designs were compared in terms of the postoperative segmental kyphosis after anterior cervical discectomy and fusion. SUMMARY OF BACKGROUND DATA: Segmental kyphosis occasionally occurs after the use of a stand-alone cage for anterior cervical discectomy and fusion. Although PEEK material seems to have less risk of segmental kyphosis compared with other materials, the occurrence of segmental kyphosis for PEEK cages has been reported to be from 0% to 29%. There have been a few reports that addressed the issue of PEEK cage design. METHOD: A total of 41 consecutive patients who underwent single-level anterior discectomy and fusion with a stand-alone cage were included. Either a round tube-type (Solis; 18 patients, S-group) or a trapezoidal tube-type (MC+; 23 patients, M-group) cage was used. The contact area between the cage and the vertebral body is larger in MC+ than in Solis, and anchoring pins were present in the Solis cage. The effect of the cage type on the segmental angle (SA) (lordosis vs. kyphosis) at postoperative month 24 was analyzed. RESULTS: Preoperatively, segmental lordosis was present in 12/18 S-group and 16/23 M-group patients (P=0.84). The SA was more lordotic than the preoperative angle in both groups just after surgery, with no difference between groups (P=0.39). At 24 months, segmental lordosis was observed in 9/18 S-group and 20/23 M-group patients (P=0.01). The patients in M-group were 7.83 times more likely than patients in S-group (P=0.04; odds ratio, 7.83; 95% confidence interval, 1.09-56.28) not to develop segmental kyphosis. CONCLUSIONS: The design of the PEEK cage used may influence the SA, and this association needs to be considered when using stand-alone PEEK cages.

Dural tear and resultant cerebrospinal fluid leaks after cervical spinal trauma.

PURPOSE: Traumatic cervical spinal cord injuries (SCIs) frequently develop dural tears and resultant cerebrospinal fluid (CSF) leaks. They are not usually identified with advanced imaging, and there are no reports on managing CSF leaks after cervical trauma. Hence, the authors evaluated the incidence of CSF leaks after cervical SCIs and described how to predict and manage CSF leaks. METHODS: An observational retrospective study was done confirming intraoperative CSF leaks among 53 patients with anterior cervical surgery after cervical spine trauma between 2004 and 2011. RESULTS: Seven patients (13.2%) had dural tears and resultant CSF leaks intraoperatively (M:F ratio of 6:1; mean age, 44.7 years). An initial poor American Spinal Injury Association (ASIA) scale was significantly associated with CSF leaks (p = 0.009). From magnetic resonance imaging (MRI), disruption of the ligamentum flavum was correlated with CSF leaks (p = 0.02). Intraoperative application of fibrin glue on the operated site, postoperative management through the early removal of the wound drain within the first 24 h and early rehabilitation were performed in patients with CSF leaks without perioperative insertion of a lumbar drain. During the follow-up period, none of the patients developed CSF-leak-related complications. CONCLUSION: The incidence of CSF leaks after traumatic cervical SCI is relatively higher than that of degenerative cervical spinal surgery. An initial poor neurological status and disruption of the ligamentum flavum on the MRI in patients were predictable factors of dural tears and CSF leaks.

Isolated abducens nerve palsy due to cerebrospinal fluid leakage following lumbar discectomy: a rare clinical entity.

BACKGROUND AND IMPORTANCE: Cerebrospinal fluid (CSF) leakage can cause abducens nerve palsy which is such a rare complication after spine surgery. CLINICAL PRESENTATION: A 48-year-old man was diagnosed with isolated abducens nerve palsy due to CSF leakage by inadvertent dural tearing after lumbar discectomy. We performed primary dural repair of CSF leakage and 1 week after, the diplopia and headache disappeared with complete resolution of CSF leakage. We will also review the clinical features and outcomes of three cases that have been reported in the literature. CONCLUSION: This rare complication of spinal surgery helped us to discuss appropriate therapeutic strategies for the early surgical management of cranial nerve palsy following CSF leakage.

Effects of rod stiffness and fusion mass on the adjacent segments after floating mono-segmental fusion: a study using finite element analysis.

PURPOSE: The aims of the present study were to compare the biomechanical effects on the adjacent segments after mono-segmental floating fusion with posterior semi-rigid or rigid stabilization, and to evaluate the effect of the amount of fusion mass on the biomechanical differences. METHODS: A detailed, nonlinear L1-S1 finite element model had been developed and validated. Then five models were reconstructed by different fixation techniques on the L3-L4 level: rigid fixation with an interbody spacer (Ti + IS), rigid fixation with a large interbody spacer (Ti + IS_all), semi-rigid fixation with an interbody spacer (PEEK + IS), semi-rigid fixation with a large interbody spacer (PEEK + IS_all), and semi-rigid fixation only (PEEK). Analyses were conducted for the case of erect standing position, flexion, and extension motion. RESULTS: At L1-L2 and L2-L3, PEEK + IS demonstrated less inter-segmental rotation and nucleus pressure increments from the intact model compared with Ti + IS. The L4-L5 and L5-S1 levels showed slightly higher values with PEEK + IS, but these differences among the instrumented models were not significant. The motion difference based on the fusion mass at the adjacent levels was at most 3%. All instrumentation cases generated a 55% higher facet contact force at the lower adjacent level (L4-L5) compared to that of the intact model during 26° extension and the largest increment was detected at the upper adjacent level (L2-L3) in the Ti + IS. Instrumentation with Ti + IS markedly increased the stress in the intervertebral disk at the upper adjacent level, while the stress with PEEK + IS appeared largest at the lower adjacent level. CONCLUSIONS: Posterior instrumentation with semi-rigid rods may lower the incidence of disk and facet degeneration in the upper adjacent segment compared to rigid rods. On the other hand, the possibility of facet degeneration will be similar for all instrumentation devices in the lower adjacent segment in the long-term. The stiffness difference between rigid and semi-rigid rods on the changes in the adjacent motion segments was more crucial than amount of fusion mass.

Chiari I malformation associated with syringomyelia: can foramen magnum decompression lead to restore cervical alignment?

PURPOSE: There are few researches that demonstrate the relationship between the extent of syringomyelia and sagittal alignment of the cervical spine. The purpose of this study is to investigate the correlation between the change of syrinx size and cervical alignment. METHODS: From January 2001 to June 2008, we operated on 207 patients who had syringomyelia. The associated diseases were categorized by Chiari I malformation, tumor, trauma, spinal stenotic lesion, inflammatory disease and idiopathic causes. Thirty patients who had Chiari I malformation associated with syringomyelia and who underwent foramen magnum decompression (FMD), participated in this study. We excluded patients with scoliosis, cervical instrumentation, tumor, trauma, myelomeningocele, hydrocephalus, tethered cord and congenital vertebral anomalies. Lateral radiographs in neutral and magnetic resonance imaging were taken pre- and postoperatively. RESULTS: Mean follow-up was 6.5 ± 1.5 years (ranged from 4.0 to 9.5 years). The mean pre- and postoperative lordosis angles at C2-C7 were -5.9° ± 1.0° and -10.4° ± 1.0°, respectively (P = 0.001). There was significant correlation between the differences of syrinx width and the cervical lordotic angles before and after surgery (P = 0.016). After FMD, syringomyelia and cervical alignment improved in 28 (93.3%) and 25 (85.18%) of 30 patients, respectively. There was significant correlation between recovery rate by Japanese Orthopaedic Association scores and the difference of the cervical lordotic angles before and after surgery (P = 0.022). CONCLUSIONS: The present results demonstrate that the decrease of syrinx size by FMD may restore the cervical lordosis. We suggest that the postoperative cervical alignment might be a predictive factor for neurological outcome.

Clinical outcomes of conservative management of spinal cord cavernous angiomas.

BACKGROUND: There have been numerous studies on the outcomes of surgery for spinal cord cavernous angiomas. However, the natural history of conservatively treated disease is not well known. The aim of this retrospective study was to investigate the outcomes of conservatively managed patients with spinal cord cavernous angioma to determine the appropriate treatment strategies. METHODS: Twenty-four patients who visited a single institution over an 11-year period and who were treated conservatively were enrolled in this study. Their medical records and radiological images were reviewed retrospectively. The neurologic status of the patients was assessed using the Japanese Orthopedic Association scoring system and the clinical presentation of the patients was classified into the following 4 categories: type A, asymptomatic; B, pain only; C, sensory deficits; and D, sensory and motor deficits. The results of types C and D patients were compared with the results of previously reported surgical series from our institution. RESULTS: The mean age of the enrolled patients was 52.0 years (21-73). The mean duration of the clinical follow-up was 60.5 months (11-119) and the follow-up using magnetic resonance imaging was 52.4 months (3-122). Cavernous angiomas presented in the cervical spinal cord in 12 patients, thoracic spinal cord in 10 patients and in multiple levels of the spinal cord in 2 patients. There were 5, 5, 7, and 7 patients, respectively, classified with types A, B, C, and D for clinical presentations. The rate of recurrent hemorrhage was 1.7 %/patient-year and all recurrent hemorrhages only developed in type C or D patients. In types C and D patients, improvement in the JOA score during the follow-up period was 0.77 ± 1.8 in the conservative group and 1.07 ± 1.8 in the surgical group (p = 0.500). However, improvement in the JOA sensory score after surgical treatment was statistically significant (P = 0.007). CONCLUSIONS: Conservative treatment may be a reasonable treatment strategy for patients with types A and B. If patients present with type C or D, surgical treatment is recommended considering the better improvements in sensory deficits and the high rate of recurrent hemorrhage in such patients.

Symmetrically medial bony gutters for open-door laminoplasty.

STUDY DESIGN: Observational cohort study. OBJECTIVE: The authors modified open-door laminoplasty in a manner that creates a bony gutter symmetrically and more medially away from the medial border of the lateral mass. SUMMARY OF BACKGROUND DATA: Cervical laminoplasty is becoming popular, but there was no definite position of bony gutter in performing open-door laminoplasty. METHODS: All of the patients underwent our modified open-door laminoplasty with medial bony gutters. The bony gutter on the open side was made 3 mm medially apart from the medial border of the lateral mass, and an opposite gutter on the hinge side was drilled symmetrically to that on the open side while preserving the ventral cortex. The lamina was kept elevated using titanium miniplates bridging the lamina and facet joint on the open side. On the computed tomography, distance of the bony gutters and the cross-sectional area were measured from C4 to C6. RESULTS: This study included consecutive 61 patients (46 men and 15 women; mean age, 61.6 y old). The average distance of the right bony gutter was 3.43 mm and that of left bony gutter was 3.35 mm. The average cross-sectional area of preoperative and postoperative computed tomography was 189.9 and 281.8 mm in all patients, respectively. In all patients, although bony gutter was placed medially, the spinal canal area was expanded significantly (P < 0.0001). Postoperative C5 palsy developed in one of the 61 patients (1.6%). Compared with patients without C5 palsy, the right bony gutter was placed much closer to the medial border of the lateral mass in a patient with C5 palsy in whom we opened the lamina on the right side. CONCLUSIONS: Our modified open-door laminoplasty with symmetrically and medially placed bony gutters produced low incidence of postoperative C5 palsy with effective expansion of the spinal canal area.

Comparative analysis of 3 different construct systems for single-level anterior cervical discectomy and fusion: stand-alone cage, iliac graft plus plate augmentation, and cage plus plating.

STUDY DESIGN: A retrospective cohort-nested longitudinal study. OBJECTIVE: To evaluate radiologic and clinically functional outcomes after single-level anterior cervical discectomy and fusion (ACDF) using 3 different fusion construct systems applying an accurate and reliable methodology. SUMMARY OF BACKGROUND DATA: ACDF is an established procedure that uses 3 different fusion construct systems: cage alone (CA), iliac tricortical bone block with plate (IP), and cage with plate construct (CP). The outcome of a previous study is quite different and did not correlate with experimental studies. METHODS: ACDF was performed on 158 patients (90 male and 68 female), who were followed up for >12 months. The patients were divided into the following 3 treatment groups: CA, IP, and CP. Factors related to outcome were also evaluated. Fusion rate, subsidence rate, and cervical angles were used to measure radiologic outcome. The Odom criteria and the visual analog scale were used to evaluate the clinical outcome. RESULTS: The fusion rate was higher for patients in the IP (87.1%) and CP (79.5%) groups than for those in the CA group (63.2%) after 12 months of follow-up (P=0.019). The subsidence rate was lower for patients in the IP (28.1%) and CP (38.5%) groups than for those in the CA group (58.6%) (P=0.010). Subsidence occurred for the anterior height regardless of constructs. Radiating arm pain showed greater relief in the CP group than in the CA group (P=0.015). It improved more in the CP group than in the IP group, but the differences were not statistically significant (P=0.388). Other clinical outcomes did not show significant differences. CONCLUSIONS: The trend of excellent radiologic outcome was observed for IP≥CP>CA. Plating may play a key role in the support of anterior height. As a result, plating prevents segmental kyphosis and subsidence and promotes bone fusion. Although the overall clinical outcomes were not different among the 3 groups, except for arm pain, more favorable trends regarding clinical outcome were observed for CP≥IP>CA.

Remodeling of adjacent spinal alignments following cervical arthroplasty and anterior discectomy and fusion.

OBJECTIVE: To evaluate the effects of cervical artificial disc replacement (ADR) and anterior discectomy and fusion (ACDF) on adjacent spinal alignments. METHODS: The cohort consisted of 33 patients who undergone single-level cervical ADR (15 patients) and ACDF (18 patients) for radiculopathy, who had not had any previous spine surgery, and who had a minimum follow-up of 2 years. Whole-spine lateral radiographs were taken at the pre-operative and follow-up consultations. Cervical lordosis, thoracic kyphosis, lumbar lordosis, and sagittal balance were measured each time. The patients filled out pre-operative and follow-up functional evaluation forms including visual analogue scale (VAS) of neck and arm. The mean follow-up durations of patients who had cervical ADR and ACDF were 28 ± 5.0 and 30 ± 5.8 months, respectively. The patients having ACDF had the higher mean age (53 ± 9.0 years) than that of patients with cervical ADR (45 ± 11.7 years). RESULTS: The cervical lordosis and thoracic kyphosis in cervical ADR group increased significantly more than those of the ACDF group in follow-up assessment (P = 0.011 and 0.012). There was no significant change of lumbar lordosis in intra- and inter-group analyses. The follow-up sagittal balances for the cervical ADR and ACDF groups moved towards a neutral value. Although the follow-up neck and arm VAS of the both groups improved than those of the pre-operative status, the groups did not differ significantly except for a difference in neck VAS, which improved more after ADR. CONCLUSIONS: The remodeling of cervical and thoracic curves after cervical ADR and ACDF was coupled and complementary. Cervical ADR contributed the restorations of angulations of cervical and thoracic spines. The neck VAS improved more after cervical ADR than after ACDF.

What is a reasonable surgical procedure for spinal extradural arachnoid cysts: is cyst removal mandatory? Eight consecutive cases and a review of the literature.

BACKGROUND: Spinal epidural arachnoid cysts (EAC) are rare and may present with myelopathy, which can be completely curable with surgery. The majority of investigators believe that the repairment of dural defect is important to treat EAC. However, the necessity of excising EACs remains controversial. The purpose of this study was to find a reasonable surgical technique for treatment of EACs after considering the clinical outcome, recurrence, and complications. METHODS: The data from 44 operations in the literature and eight cases from our own experience were analyzed. This data included the surgical method, patient characteristics, level and size of the EAC, global assessment of the clinical outcomes, and the incidence of recurrence. RESULTS: The recurrence rate was 2.0 % and 66.7 % in the patients who underwent repair of the dural defect and in those failed to repair of the dural defect, respectively (p = 0.007). The recurrence rate was 8.3 % and 3.6 % in patients who underwent complete EAC excision totally, and those who underwent EAC fenestration only, respectively (p = 0.590). The clinical outcome in patients with repaired dural defects was significantly better than that in patients with unrepaired dural defects (2.61 vs.1.67) (p = 0.027). The clinical outcome score was 2.42 and 2.68 in patients who underwent complete EAC excision and those who underwent EAC fenestration only, respectively (p = 0.158). The mean EAC length was 5.04 vertebral body levels (range, 2-13). Six of the 51 patients (11.7 %) had multiple EACs. CONCLUSIONS: Total excision of EACs may have little benefit in terms of cyst recurrence and clinical outcome. The procedure for EAC resection carries a risk of complications such as kyphosis. If EAC resection is performed, we suggest that a tailored short-level laminotomy be used to allow for the repair of dural defects. Particularly in patients with small EAC, a partial hemilaminectomy with dural defect repair may be a possible method to reduce complications.

Surgical outcome of percutaneous endoscopic interlaminar lumbar diskectomy for recurrent disk herniation after open diskectomy.

STUDY DESIGN: Technical report. OBJECTIVE: To present a detailed surgical technique of percutaneous endoscopic interlaminar diskectomy (PEID) for recurrent lumbar disk herniation and present features of postoperative magnetic resonance images that were unavailable in previous studies. SUMMARY OF BACKGROUND DATA: Revision lumbar diskectomy is troublesome because of the difficulty in dissecting a surgical scar. Endoscopic diskectomy is regarded as an alternative method with comparable clinical outcome and less complication. Technically, a transforaminal approach is similar to a virgin operation, whereas an interlaminar approach is not, because of the scar tissue. There have been only 2 papers describing a PEID surgical procedure. Sharing details of the surgical technique is important in furthering the adoption of this technique, when it is indicated. METHODS: We operated on 10 patients (M:F=6:4; mean age, 61.2±11.6 y) with PEID for recurrent lumbar disk herniation after open diskectomy. The level operated was L5-S1 in 5 cases, L4-5 in 4, and L2-3 in 1. During operation, we dissected the scar tissue from the medial facet joint with a working channel and removed the reherniated disk material after retraction of the scar tissue and the neural tissue together. Dissection of the scar tissue from the neural tissue was not attempted. The follow-up period was 14.4±9.9 months. RESULTS: In all 10 patients, the reherniated disk materials were removed successfully. There was no incidence of dural tear. Postoperative magnetic resonance imaging showed good decompression with thecal sac reexpansion irrespective of the attached scar tissue, except in 1 patient. Excellent or good outcome by Macnab criteria was obtained in 6 of 10 patients, fair outcome in 2, and poor in 2 patients. Rerecurrence occurred in 1 patient 1 year after the surgery. CONCLUSIONS: PEID with dissection of the scar tissue from the medial facet joint rather than from the neural tissue may be an effective alternative surgical method for recurrent disk herniation.