Jin Hoon Park

Comparative Analysis of Cervical Arthroplasty Using Mobi-C and Anterior Cervical Discectomy and Fusion Using the Solis -Cage

OBJECTIVEnAlthough anterior cervical discectomy and fusion (ACDF) is the standard treatment for degenerative cervical disc disease, concerns regarding adjacent level degeneration and loss of motion have suggested that arthroplasty may be a better alternative. We have compared clinical and radiological results in patients with cervical disc herniations treated with arthroplasty and ACDF.nnnMETHODSnWe evaluated 53 patients treated for cervical disc herniations with radiculopathy, 21 of whom underwent arthroplasty and 32 of whom underwent ACDF. Clinical results included the Visual Analogue Scale (VAS) score for upper extremity radiculopathy, neck disability index (NDI), duration of hospital stay and convalescence time. All patients were assessed radiologically by measuring cervical lordosis, segmental lordosis and segmental range-of-movement (ROM) of operated and adjacent disc levels.nnnRESULTSnMean hospital stay (5.62 vs. 6.26 days, p<0.05) and interval between surgery and return to work (1.10 vs. 2.92 weeks, p<0.05) were significantly shorter in the arthroplasty than in the fusion group. Mean NDI and extremity VAS score improved after 12 months in both groups. Although it was not significant, segmental ROM of adjacent levels was higher in the fusion group than in the arthroplasty group. And, segmental motion of operated levels in arthroplasty group maintained more than preoperative value at last follow up.nnnCONCLUSIONnAlthough clinical results were similar in the two groups, postoperative recovery was significantly shorter in the arthroplasty group. Although it was not significant, ROM of adjacent segments was less in the arthroplasty group. Motion of operated levels in arthroplasty group was preserved at last follow up.

The safety and accuracy of freehand pedicle screw placement in the subaxial cervical spine: a series of 45 consecutive patients.

Study Design. Retrospective cohort study. Objective. To assess the safety and accuracy of subaxial cervical pedicle screw placement with freehand technique and to report the technical nuances. Summary of Background Data. Although the efficacy and safety of freehand screw fixation in thoracic and lumbar vertebrae is proven, reports on this technique of screw insertion in the subaxial cervical spine are lacking. Methods. From March 2012 to September 2013, 45 consecutive patients underwent posterior cervical fusion. The diagnoses were trauma (22 patients), degenerative disease (18 patients), discitis/osteomyelitis (2 patients), pathological fracture (2 patients), and postlaminoplasty kyphosis (1 patient). Preoperative computed tomography (CT) was performed in all patients. We included patients whose outer diameter of the pedicle was greater than 3.0 mm. The standard entry points were modified according to the CT anatomy of each patient. A small pilot hole was fashioned at a predetermined entry point. Then, a 2.5-mm diameter curved pedicle probe was slowly inserted with a medial trajectory into the pedicle. After ball-tip probing and tapping, the screw was inserted. If ball-tip probing was suggestive of risk to neurovascular structures, conversion to a lateral mass screw was performed. Postoperatively, a CT scan was performed in all patients and the conversion rate from pedicle to lateral mass screw was recorded. The breech rate of pedicle screws was also analyzed. Results. There were 256 planned pedicle screws and 20 incidences (7.8%) of conversion to lateral mass screws. Lateral wall violation was observed in 14 pedicle screws (accuracy rate: 94.1%) on the postoperative CT scan. No medial, superior, and inferior pedicle wall violations were observed. There was no patient who developed symptoms related to vertebral artery stenosis. Conclusion. Adherence to the surgical tips presented in this article may lead to safe and effective freehand placement of cervical pedicle screws. Level of Evidence: 3

A single-stage posterior approach with open reduction and pedicle screw fixation in subaxial cervical facet dislocations

OBJECTnThe optimal treatment for cervical facet dislocations is controversial, but the generally accepted process recommends an initial closed reduction with the next step determined according to the success of the closed reduction and the presence of traumatic disc herniation. This study aimed to show the efficacy of a posterior approach performed with an open reduction and pedicle screw fixation with removal of disc particles, if required, in the management of subaxial cervical dislocations.nnnMETHODSnBetween March 2012 and September 2013, 21 consecutive patients with cervical facet dislocations were enrolled. The affected levels were as follows: 4 at C3-4; 2 at C4-5; 5 at C5-6; and 10 at the C6-7 level. Seven patients had traumatic disc herniations. Closed reduction was not attempted; a prompt posterior cervical surgery was performed instead. After open reduction, pedicle screw fixation was performed. In cases with traumatic disc herniation, herniated disc fragments were excised via a posterolateral approach and successful decompressions were determined by postoperative MRI studies. Clinical outcomes were assessed using the American Spinal Injury Association (ASIA) grading system. Radiological outcomes were assessed by comparing the degree of subluxation and the angle of segmental lordosis between pre- and postoperative CT scans.nnnRESULTSnAll patients improved neurologically. The mean segmental angles improved from 7.3° ± 8.68° to -5.9° ± 4.85°. The mean subluxation improved from 23.4% ± 16.52% to 2.6% ± 7.19%. Disc fragments were successfully removed from the 7 patients with herniated discs, as shown on MRI.nnnCONCLUSIONSnOpen reduction followed by pedicle screw fixation or posterolateral removal of herniated disc fragments is a good treatment option for cervical facet dislocations.

Long-term outcomes of 2 cervical laminoplasty methods: midline splitting versus unilateral single door.

Background: Two major current methods are midline splitting laminoplasty (MSL) and unilateral single-door laminoplasty (USDL). Few studies have compared the 2 techniques. Methods: We retrospectively analyzed the outcomes of 100 consecutive myelopathy patients who underwent decompressive laminoplasty between January 2004 and June 2008. The mean follow-up duration was 48.2 months. Results: The mean Japanese Orthopedic Association scores changed from 6.9 to 11.9 in the MSL group and from 6.2 to 12.4 in the USDL group, resulting in mean calculated recovery rates of 55.5% and 63.0%, respectively (P=0.14). Mean cervical lordosis declined from 12.0 to 10.2 degrees in the MSL group and from 10.3 to 8.5 degrees in the USDL group (P=0.24). Mean cervical range of motion declined from 27.8 to 25.6 degrees in the MSL group, and from 23.4 to 16.0 degrees in the USDL group (P=0.38). Bony spinal canal dimension increased from 201.2 to 280.8 mm2 in the MSL group and from 204.3 to 331.7 mm2 in the USDL group (P<0.001). In the USDL group, 6 patients experienced postoperative neck pain, 7 experienced C5 palsy, and 2 experienced cerebrospinal fluid leakage. No such complications occurred in the MSL group (P≥0.05 for both complications). Conclusions: MSL and USDL patients had similar long-term clinical and radiologic outcomes, except that bony canal expansion was greater in the latter. We believe that removal of the ligamentum flavum and drilling of the internal bony edge were factors in the favorable clinical outcomes and low rate of complications in the MSL group.

Mid-term follow-up of clinical and radiologic outcomes in cervical total disk replacement (Mobi-C): incidence of heterotopic ossification and risk factors.

Introduction: Cervical arthroplasty has been shown to have successful, short-term and long-term radiologic and clinical outcomes. The incidence of and predisposing factors for heterotopic ossification (HO) have not been determined. We retrospectively assessed the intermediate-term clinical and radiologic outcomes, especially the incidence of HO and its risk factors. Methods: Our patient population consisted of 75 patients (85 levels) with cervical disk herniation. Mean follow-up was 40 months, with a minimum follow-up of 24 months. The numeric rating scale scores of neck and arm pain, the neck disability index, and Odom criteria were measured preoperatively and at 24 months postoperatively. Cervical overall lordosis, segmental lordosis, and range of motion at the operative level were evaluated immediately after surgery and at 1, 3, 6, 12, and 24 months postoperatively. The incidence and location of HO were evaluated at 12 and 24 months postoperatively. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for HO. Results: The mean numeric rating scale scores and neck disability index scores decreased significantly over 24 months. According to Odom criteria, this represented an overall success rate of 86.7%. Mean segmental lordosis and motion increased and then decreased until 24 months. HO occurred in 67 levels at 12 months postoperatively, increasing to 80 levels at 24 months. The multivariate logistic regression test showed a statistically significant difference when using a different surgical technique (P=0.049). Conclusions: Intermediate follow-up of cervical arthroplasty showed good clinical outcomes, although there was a trend toward reduction in alignment and motion at 24 months. The overall HO occurrence was 94.1% at 24 months. In our study, the most important factor affecting HO was the different surgical techniques.

Radiographic Analysis of Instrumented Posterolateral Fusion Mass Using Mixture of Local Autologous Bone and b-TCP (PolyBone®) in a Lumbar Spinal Fusion Surgery

OBJECTIVEnAlthough iliac crest autograft is the gold standard for lumbar fusion, the morbidity of donor site leads us to find an alternatives to replace autologous bone graft. Ceramic-based synthetic bone grafts such as hydroxyapatite (HA) and b-tricalcium phosphate (b-TCP) provide scaffolds similar to those of autologous bone, are plentiful and inexpensive, and are not associated with donor morbidity. The present report describes the use of Polybone® (Kyungwon Medical, Korea), a beta-tricalcium phosphate, for lumbar posterolateral fusion and assesses clinical and radiological efficacy as a graft material.nnnMETHODSnThis study retrospectively analyzed data from 32 patients (11 men, 21 women) who underwent posterolateral fusion (PLF) using PolyBone® from January to August, 2008. Back and leg pain were assessed using a Numeric Rating Scale (NRS), and clinical outcome was assessed using the Oswestry Disability Index (ODI). Serial radiological X-ray follow up were done at 1, 3, 6 12 month. A computed tomography (CT) scan was done in 12 month. Radiological fusion was assessed using simple anterior-posterior (AP) X-rays and computed tomography (CT). The changes of radiodensity of fusion mass showed on the X-ray image were analyzed into 4 stages to assess PLF status.nnnRESULTSnThe mean NRS scores for leg pain and back pain decreased over 12 months postoperatively, from 8.0 to 1.0 and from 6.7 to 1.7, respectively. The mean ODI score also decreased from 60.5 to 17.7. X-rays and CT showed that 25 cases had stage IV fusion bridges at 12 months postoperatively (83.3% success). The radiodensity of fusion mass on X-ray AP image significantly changed at 1 and 6 months.nnnCONCLUSIONnThe present results indicate that the use of a mixture of local autologous bone and PolyBone® results in fusion rates comparable to those using autologous bone and has the advantage of reduced morbidity. In addition, the graft radiodensity ratio significantly changed at postoperative 1 and 6 months, possibly reflecting the inflammatory response and stabilization.

Sparganosis in the lumbar spine : report of two cases and review of the literature.

Sparganosis is a rare parasitic infection affecting various organs, including the central nervous system, especially the lumbar epidural space. This report describes the identification of disease and different strategies of treatments with preoperative information. A 42-year-old man presented with a 2-year history of urinary incontinence and impotence. He had a history of ingesting raw frogs 40 years ago. Magnetic resonance (MR) imaging showed an intramedullary nodular mass at conus medullaris and severe inflammation in the cauda equina. A 51-year-old woman was admitted with acute pain in the left inguinal area. We observed a lesion which seemed to be a tumor of the lumbar epidural space on MR imaging. She also had a history of ingesting inadequately cooked snakes 10 years ago. In the first patient, mass removal was attempted through laminectomy and parasite infection was identified during intra-operative frozen biopsy. Total removal could not be performed because of severe arachnoiditis and adhesion. We therefore decided to terminate the operation and final histology confirmed dead sparganum infection. We also concluded further surgical trial for total removal of the dead worm and inflammatory grannulation totally. However, after seeing another physician at different hospital, he was operated again which resulted in worsening of pain and neurological deficit. In the second patient, we totally removed dorsal epidural mass. Final histology and enzyme-linked immunosorbent assay (ELISA) confirmed living sparganum infection and her pain disappeared. Although the treatment of choice is surgical resection of living sparganum with inflammation, the attempt to remove dead worm and adhesive granulation tissue may cause unwanted complications to the patients. Therefore, the result of preoperative ELISA, as well as the information from image and history, must be considered as important factors to decide whether a surgery is necessary or not.

Prognostic Factor Analysis for Management of Chronic Neck Pain : Can We Predict the Severity of Neck Pain with Lateral Cervical Curvature?

Objective Although little is known about its origins, neck pain may be related to several associated anatomical pathologies. We aimed to characterize the incidence and features of chronic neck pain and analyze the relationship between neck pain severity and its affecting factors. Methods Between March 2012 and July 2013, we studied 216 patients with chronic neck pain. Initially, combined tramadol (37.5 mg) plus acetaminophen (325 mg) was administered orally twice daily (b.i.d.) to all patients over a 2-week period. After two weeks, patients were evaluated for neck pain during an outpatient clinic visit. If the numeric rating scale of the patient had not decreased to 5 or lower, a cervical medial branch block (MBB) was recommended after double-dosed previous medication trial. We classified all patients into two groups (mild vs. severe neck pain group), based on medication efficacy. Logistic regression tests were used to evaluate the factors associated with neck pain severity. Results A total of 198 patients were included in the analyses, due to follow-up loss in 18 patients. While medication was successful in reducing pain in 68.2% patients with chronic neck pain, the remaining patients required cervical MBB. Lateral cervical curvature, such as a straight or sigmoid type curve, was found to be significantly associated with the severity of neck pain. Conclusion We managed chronic neck pain with a simple pharmacological management protocol followed by MBB. We should keep in mind that it may be difficult to manage the patient with straight or sigmoid lateral curvature only with oral medication.

Feasibility of Posterior Cervical Foraminotomy in Cervical Foraminal Stenosis: Prediction of Surgical Outcomes by the Foraminal Shape on Preoperative Computed Tomography.

Study Design. A retrospective cohort study. Objective. The aim of this study was to compare the feasibility of posterior cervical laminoforaminotomy (PCF) for V- or parallel-shaped foraminal stenosis (FS). Summary of Background Data. During PCF, the need for extensive facet resection would depend on the extent of any pathology. When resection is extensive, the possibilities of instability and incomplete decompression should be considered. Methods. From March 2004 to March 2015, we enrolled 36 patients following single-level PCF procedures for FS. We classified patients by foraminal shape on preoperative computed tomography (CT) scan into V-shaped and parallel-shaped groups. We then compared arm and neck pain using a numeric rating scale (NRS) and clinical outcomes using Odom criteria. Radiological evaluation included dynamic X-rays for instability and CT scans for facet resection. Result. We enrolled 16 and 20 patients in the V-shape and parallel-shape groups, respectively. By Odom criteria, no patient was graded fair or poor in the V group, but five patients were graded as fair and one patient as poor in the parallel group. Continued postoperative arm pain at 1 year, which was related to incomplete decompression, was significantly higher in parallel group. Only one patient complained of postoperative neck pain with an NRS >5, and another five patients sustained radiculopathy with an NRS >5. Among five patients who complained sustained radiculopathy, one patient required revision surgery for incomplete decompression. The amount of facet removal was not different significantly between groups, and no patient had postoperative instability. Conclusion. Although PCF seems to be a good surgical option for V-shaped FS, we experienced worse outcomes for patients with parallel-shaped FS. We recommend that ACDF or more aggressive posterior foraminotomy be performed with fusion when presented with parallel neuroforaminal compression. Level of Evidence: 4

Widening of the safe trajectory range during subaxial cervical pedicle screw placement: advantages of a curved pedicle probe and laterally located starting point without creating a funnel-shaped hole

OBJECTIVE The small diameter of cervical pedicles and a large transverse cervical pedicle angle are challenges that have led spinal surgeons to investigate how they could achieve a wider safety trajectory and reduce the insertion angle during cervical pedicle screw (CPS) placement. In this paper, the authors detail the advantages of using a curved pedicle probe and a laterally located entry point for overcoming these challenges. METHODS From March 2012 to May 2016, the authors performed posterior cervical fusions using CPSs on 119 consecutive patients. The lateral mass screw conversion and the CPS breach rate were analyzed. Using preoperative CT, it was determined that θlat is similar to the anatomical pedicle angle, and θmed is the minimally acceptable medial angle. The actual insertion medial angle (θins) was determined by postoperative CT. To identify how much of the medial angle on θins could be reduced from the anatomical pedicle angle (θlat), and how much closer to θmed, (θins-θmed) / (θlat-θmed) was calculated. To verify shifting of the entry point and widening of the trajectory, the mean df/Df (i.e., shifted facet point/planned facet point) values were analyzed. RESULTS The total number of planed CPSs was 759, the conversion rate was 4.61% (35/759), and the accuracy rate was 95.9% (694/724). The authors could calculate that θins could be expected near the 90%, 80%, 80%, 80%, and 110% value of θlat on C-3, C-4, C-5, C-6, and C-7 levels, respectively, with the (θins-θmed) / (θlat-θmed) equation. The mean df/Df values were 0.64, 0.62, 0.63, 0.63, and 1.24 on the C3-7 levels, respectively. CONCLUSIONS Through the use of a curved pedicle probe and a laterally located starting point, the planned and laterally located entry point medial shift was made during CPS placement. The entry point shift yielded a wider, safe trajectory and reduced the burden of making a large medial angle, similar to an anatomical cervical pedicle lateral angle, for safe CPS placement without creating a funnel-shaped hole.