Chang Ming Guo

Intermediate Results of the Prestige LP Cervical Disc Replacement: Clinical and Radiological Analysis With Minimum Two-Year Follow-up.

Study Design. Prospective study. Objective. Present results of Prestige LP artificial cervical disc replacement (ADR). Summary of Background Data. Motion preservation with ADR can potentially reduce adjacent segment degeneration. Methods. Forty patients with 59 Prestige LP ADR were analyzed. Cervical range of motion, Neck Disability Index, Visual Analogue, Short Form-36, Modified American Academy of Orthopedic Surgeons, and Japanese Orthopedic Association scores and radiographs were evaluated. Clinical results were compared with anterior cervical discectomy and fusion. Results. There were 21 females and 19 males. Mean age was 43.9 years. Mean follow-up was 2.9 years. Of the patients, 62.5% had single level replacement-mainly C56 level (56%); 52.5% had myelopathy and 47.5% radiculopathy; 50% of neural compression was due to herniated disc, 45% due to spondylosis, and 5% due to both. There was significant improvement in the American Academy of Orthopedic Surgeons and Visual Analogue scores (P < 0.05) at 6 months and 2 years. There was significant improvement in the Neck Disability Index from a mean of 42.2 preoperation to 16.4 at 6 months and 15.2 at 2 years (P < 0.05). The mean Japanese Orthopedic Association score improved significantly from 14.7 preoperation to 15.7 at 6 months and 15.6 at 2 years (P < 0.05). There was significant improvement in all aspects of the Short Form-36 scores except general health (P < 0.05) at 6 months and 2 years. There was no significant difference in the clinical outcomes between ADR and anterior cervical discectomy and fusion. Segmental alignment (mean 8°, 14°, and 13° lordotic at preoperation, 6 months, and 2 years postoperation, respectively) and global alignment (mean 15.7°, 16.2°, and 17.3° lordotic at preoperation, 6 months, and 2 years postoperation, respectively) were maintained. Dynamic radiographs showed significant segmental motion with a 6 months mean motion of 11.1° and a 2-year mean motion of 13.9° (P < 0.05). Conclusion. Prestige LP ADR showed significant improvement in clinical outcomes at 2 years. It restores segmental lordosis and preserves segmental motion up to 2 years postoperation.

Erectile Dysfunction in Young Surgically Treated Patients With Lumbar Spine Disease : A Prospective Follow-up Study

Study Design. This is a prospective study. Objective. The prevalence of erectile dysfunction (ED) in patients younger than 50 years with fracture-unrelated lumbar spine disease requiring surgical decompression without other risk factors for ED is evaluated. Summary of Background Data. There is little literature documenting ED in young patients with atraumatic lumbar spine disease. Methods. All male patients younger than 50 years who underwent lumbar spine surgery during June 2006 to November 2007 without risk factors for ED were included. Patient demographics, neurological dysfunction, visual analogue scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), North American Spine Society score for neurogenic symptoms (NS), and the International Index of Erectile function (IIEF-5) scores were recorded preoperatively, at 1, 3, and 6 months. Results. There were 61 patients with mean age 38.4 years (SD = 7.0; range, 20–49). Most of patients had (43 or 70.5%)prolapsed intervertebral disc with discectomy being the commonest operation. Mean VAS scores, ODI, and NS improved significantly postoperatively. However, the mean IIEF-5 scores did not. Preoperatively, there was no correlation between ED and VAS scores on back pain (P = 0.70), leg pain (P = 0.91), ODI (P = 0.93), or NS (P = 0.51). At 6 months, patients with NS > 70 had an increased risk of ED (P = 0.03). Eighty percent of patients with NS > 70 had ED compared with 30% of patients with NS ⩽ 70. There was, however, no correlation between ED with ODI (P = 0.38) and VAS scores on back pain (P = 0.20) or leg pain (P = 0.08) at 6 months. Conclusion. The incidence of ED in patients younger than 50 years with nonfracture-related lumbar spine disease undergoing surgery without risk factors was 34.3%. Despite improvement in VAS, ODI, and NS scores postoperatively, ED did not improve. Patients with NS > 70 postoperatively were more likely to have ED reflecting possible permanent nerve damage from lumbar spine pathology.

Comparison of Clinical Outcomes and Radiographic Measurements in 4 Different Treatment Modalities for Osteoporotic Compression Fractures: Retrospective Analysis.

Study Design: We conducted a retrospective analysis of a prospectively collected database in a tertiary hospital over 10 years. Objective: Treatment for vertebral compression fractures remains an area of controversy with respect to timing and type of surgical management. We analyzed the clinical outcomes and radiographic measurements of 4 different modalities of treatment for these fractures. Summary of Background Data: From 2001 to 2011, we analyzed a total of 363 patients after failure of 30 days of conservative management. These patients were then further managed either conservatively or with vertebroplasty, balloon kyphoplasty, or sky bone expander. Outcomes were assessed by using self-report measures: Visual Analog Score; functional measures: Oswestry Disability Index and Short-Form 36; and physiological measures: preoperative and postoperative radiographs. Methods: The outcome measures were assessed for 6 months for those treated conservatively and up till 2 years for those treated surgically. Radiographic measurements of the spine were correlated with the clinical outcomes. Results: A total of 62 patients (12.1%) were treated conservatively, 148 (40.8%) with vertebroplasty, 97 (26.7%) with balloon kyphoplasty, and 56 (15.4%) with sky bone expander. We found significant improvements in Visual Analog Score, Oswestry Disability Index, and Short-Form-36 scores for all groups after 1-month follow-up (P<0.05), with the surgical groups demonstrating a greater improvement in pain scores after the first postoperative day (P<0.0001) when compared with the conservative group. The improvements in outcomes in those treated surgically were sustained for up to 2 years with no significant difference (P>0.05) among the surgical groups. We also found significant improvement (P<0.005) in anterior vertebral and kyphotic wedge angle after surgical intervention. Conclusions: We have shown that early surgical intervention allows for quicker pain relief compared with conservative treatment, with similar improvements in anterior vertebral height and kyphotic wedge angle between all 3 groups of surgical management.

Spontaneous cervical spinal epidural hematoma in the postpartum period.

Study Design. We present the case study of a 31-year-old lady who had a spontaneous cervical spinal epidural hematoma in the postpartum period and who presented with sudden onset of neck pain and lower limb weakness for which an emergency decompressive laminectomy was performed with neurological recovery. Objective. To report on the spontaneous spinal epidural hematoma in the postpartum period, which is a rare complication during pregnancy and requires early recognition and expedient intervention to prevent permanent neurological sequelae. Summary of Background Data. This complication has been described only once previously in the postpartum period. The recovery of the patient described here highlights the importance of early recognition and surgical intervention. Methods. A case report of a spontaneous cervical spinal epidural haematoma in the postpartum period is presented and the pertinent literature is then reviewed. Results. The patient had neurological recovery at 1-year follow-up, although she required clean intermittent self-catheterization once daily for bladder dysfunction. Conclusion. Early recognition and intervention for our patient allowed for neurological recovery with a spontaneous cervical spinal epidural hematoma in the postpartum period.

Cortical Reorganization Is Associated with Surgical Decompression of Cervical Spondylotic Myelopathy

Background. Cervical spondylotic myelopathy (CSM) results in sensorimotor limb deficits, bladder, and bowel dysfunction, but mechanisms underlying motor plasticity changes before and after surgery are unclear. Methods. We studied 24 patients who underwent decompression surgery and 15 healthy controls. Patients with mixed upper and lower limb dysfunction (Group A) and only lower limb dysfunction (Group B) were then analysed separately. Results. The sum amplitude of motor evoked potentials sMEP (p < 0.01) and number of focal points where MEPs were elicited (N) (p < 0.001) were significantly larger in CSM patients compared with controls. For Group A (16 patients), sMEP (p < 0.01) and N (p < 0.001) showed similar findings. However, for Group B (8 patients), only N (p = 0.03) was significantly larger in patients than controls. Group A had significantly increased grip strength (p = 0.02) and reduced sMEP (p = 0.001) and N (p = 0.003) after surgery. Changes in sMEP (cMEP) significantly correlated inversely with improved feeding (p = 0.03) and stacking (p = 0.04) times as was the change in number of focal points (NDiff) with improved writing times (p = 0.03). Group B did not show significant reduction in sMEP or N after surgery, or significant correlation of cMEP or NDiff with all hand function tests. No significant differences in H reflex parameters obtained from the flexor carpi radialis, or central motor conduction time changes, were noted after surgery. Discussion. Compensatory expansion of motor cortical representation occurs largely at cortical rather than spinal levels, with a tendency to normalization after surgery. These mirrored improvements in relevant tasks requiring utilization of intrinsic hand muscles.

Pregabalin and Radicular Pain Study (PARPS) for Cervical Spondylosis in a Multiracial Asian Population

Background Pain from cervical spondylosis (CS) may result from degenerative spinal canal stenosis (cervical spondylotic myelopathy (CSM)) or lateral recesses compromise, leading to nerve root compression (cervical spondylotic radiculopathy (CSR)). Pregabalin was shown to be effective in randomized, placebo-controlled trials for post-herpetic neuralgia and diabetic neuropathy. We evaluate its efficacy in CS with underlying CSR or CSM in a prospective study comprising Asian patients for the first time. Methods Patients with CS and CSR or CSM (clinical, MRI, or electrophysiological evidence) presenting with neuropathic pain were recruited. We excluded patients with diabetes, underlying neurological disease or who were previously on antiepileptics. Pregabalin 75 mg bd was administered for 4 weeks, after which dosage was increased to 150 mg bd for another 4 weeks if the visual analog scale (VAS) was not reduced by 50%. In addition, we monitored the short form McGill pain questionnaire (SFMPQ) at baseline, 4 weeks and 8 weeks. Mood changes were monitored using the hospital anxiety and depression score (HADS) with an identical timeline. Results We recruited 50 patients, of which 23 completed the trial. Of the 27 who withdrew, 12 (44%) were for somnolence. Thirteen patients’ (54%) dosages remained at 75 mg and 11 patients’ (46%) dosages were escalated to 150 mg bd. There were significantly reducing trends from baseline for VAS (ANOVA, F(1, 21) = 25.4, P < 0.0005), SFMPQ (sensory) (F(1, 22) = 11.2, P = 0.003), and SFMPQ (affective) (F(1, 21) = 10.9, P = 0.008). For VAS, there was significant reduction at 4 weeks (P = 0.001) and 8 weeks (P < 0.0005) compared to baseline. For SFMPQ (sensory), there was significant reduction at 4 weeks (P = 0.01) and 8 weeks (P = 0.006) in scores compared to baselines. For SFMPQ (affective), there was significant reduction at 4 weeks (P = 0.04) and 8 weeks (P = 0.008) in scores compared to baseline. No significant anxiety (F(1, 4) = 1.3, P = 0.32) or depression (F(1, 4) = 0.06, P = 0.82) changes were observed in the HADS. Conclusion Pregabalin is efficacious in alleviation of pain symptoms related to CSR as a first-line single agent, evaluated by quantitative severity and other experiential scales. No significant mood changes reported in other studies were demonstrated. Somnolence was commonest adverse effect leading to high dropout rates, occurring early even at the lowest dose. The findings suggest the need for further studies of efficacy at lower dosages, particularly in the Asian population.

Systematic re-evaluation of intraoperative motor-evoked potential suppression in scoliosis surgery

BackgroundMotor- (MEP) and somatosensory-evoked potentials (SSEP) are susceptible to the effects of intraoperative environmental factors.MethodsOver a 5-year period, 250 patients with adolescent idiopathic scoliosis (AIS) who underwent corrective surgery with IOM were retrospectively analyzed for MEP suppression (MEPS).ResultsOur results show that four distinct groups of MEPS were encountered over the study period. All 12 patients did not sustain any neurological deficits postoperatively. However, comparison of groups 1 and 2 suggests that neither the duration of anesthesia nor speed of surgical or anesthetic intervention were associated with recovery to a level beyond the criteria for MEPS. For group 3, spontaneous MEPS recovery despite the lack of surgical intervention suggests that anesthetic intervention may play a role in this process. However, spontaneous MEPS recovery was also seen in group 4, suggesting that in certain circumstances, both surgical and anesthetic intervention was not required. In addition, neither the duration of time to the first surgical manoeuver nor the duration of surgical manoeuver to MEPS were related to recovery of MEPS. None of the patients had suppression of SSEPs intraoperatively.ConclusionThis study suggests that in susceptible individuals, MEPS may rarely occur unpredictably, independent of surgical or anesthetic intervention. However, our findings favor anesthetic before surgical intervention as a proposed protocol. Early recognition of MEPS is important to prevent false positives in the course of IOM for spinal surgery.

Motor and somatosensory abnormalities are significant etiological factors for adolescent idiopathic scoliosis

OBJECTIVE In adolescent idiopathic scoliosis (AIS), we explore the role of lateralized motor and somatosensory abnormalities as a possible etiological factor. METHODS Intraoperative transcranial electrical stimulation was performed in 15 AIS and 14 adult degenerative scoliosis (ADS) patients. Inter-side motor output balance (MOB) by comparing the ratios of right to left motor evoked potentials (MEP) amplitudes, and inter-side motor output excitability (MOE) computed with MEP amplitude, was determined separately for both patients groups. For somatosensory evoked potentials (SSEP), peak to peak P37 amplitudes from right and left lower limb SSEP and inter-side P37 amplitude ratios were obtained. RESULTS Inter-side MOB was significantly asymmetric in AIS patients, contributed mainly by inter-side MOB changes in the upper than the lower limbs. Inter-side MOE comparisons of ipsilateral and contralateral MEP amplitudes were significantly different between AIS and ADS patients. Mean upper limb MEP amplitudes were significantly reduced in AIS patients. Amplitude of the right upper limb MEPs were positively correlated with inter-side MEP ratio. AIS patients show larger mean MEP amplitudes on the same side as the scoliotic curve. Overall, no correlation of Cobbs angle or total levels of scoliosis involvement with inter-side MOB and MOE parameters was found. Inter-side SSEP ratios were significantly higher in AIS patients. CONCLUSIONS Primary dysfunctional and distributed motor output contributing to abnormalities of inter-side MOB and MOE changes involving the upper limbs is evident in AIS. Simultaneous but independent somatosensory and motor observations seen these patients suggest a central mechanism as an etiological factor.