Kunihiko Sasai, Masayuki Umeda, Tohkun Maruyama, Ei Wakabayashi and Hirokazu Iida
Surgical outcome and radiographic changes after microsurgical bilateral decompression via a unilateral approach (MBDU) for lumbar spinal canal stenosis during midterm follow-up periods (> 2 years) have not been reported. The authors retrospectively investigated surgical outcomes after MBDU in patients with lumbar degenerative spondylolisthesis with stenosis in comparison with patients with degenerative stenosis during a minimum follow-up period of 2 years. Radiographic changes at the affected intervertebral level were analyzed during that follow-up period.
Forty-eight patients (23 in the spondylolisthesis group, 25 in the degenerative stenosis group) were included in the study. The average follow-up period was 46 months (range 24–71 months). Surgical outcome was evaluated using the Neurogenic Claudication Outcome Score (NCOS) and the Oswestry Disability Index (ODI). Additionally, the back pain score within the NCOS was also compared. There were no statistically significant differences between the spondylolisthesis group and the degenerative stenosis group with regard to sex, age, follow-up period, operating time, blood loss, surgical sites, approach side, preoperative NCOS, preoperative back pain score, and preoperative ODI. Comparisons were also made between groups using 2 satisfaction measurements at the last follow-up visit. Radiographically, intervertebral angles of 80 sites and slip percentages of 24 sites were measured preoperatively and at the last follow-up.
No patient in either group had additional surgery in the lumbar spine, including fusion procedures. The NCOS, back pain score, and ODI had significantly improved at the last follow-up in both groups. There were no significant differences between the 2 groups in these 3 parameters and the 2 satisfaction measurements at the last follow-up, although those for the spondylolisthesis group indicated a somewhat worse outcome. Intervertebral angles, dynamic intervertebral angles, and dynamic slip percentage did not significantly change after surgery, whereas only slip percentage significantly increased postoperatively (p = 0.0319).
A satisfactory outcome of MBDU persisted for a period longer than 2 years for patients with degenerative spondylolisthesis with stenosis as well as for those with degenerative stenosis. Radiographically in both groups this less invasive procedure was not likely to result in postoperative dynamic instability at the affected level, although the slippage progressed in the spondylolisthesis group.
Kunihiko Sasai, Masayuki Umeda, Takanori Saito, Hiroyuki Ohnari, Ei Wakabayashi and Hirokazu Iida
The authors retrospectively investigated the surgical outcomes and radiographically documented changes after microsurgical posterior foraminotomy with en bloc laminoplasty in patients with cervical spondylotic radiculo-myelopathy (CSRM), including cervical spondylotic amyotrophy (CSA), during a period greater than 2 years.
Thirty-four consecutive patients (24 men and 10 women) were included in this study. Twenty patients had preoperative radicular pain, and CSA was diagnosed in 14 patients. The mean age at the time of surgery was 61 years (range 43–77 years). The follow-up period ranged from 2 to 6.5 years (mean 3.4 years). Foraminotomy was performed at 49 sites. Neurological improvement was evaluated using the Japanese Orthopaedic Association (JOA) scoring system; radicular pain and deltoid muscle strength were also evaluated clinically. Cervical lordosis, flexion–extension angles, range of motion (ROM), and the angulation and the extent of vertebral slippage at the affected nerve root levels were measured preoperatively and at last follow-up examination.
The mean rate of JOA score improvement was 67.2% (range 22.2–100%). In all 20 patients, preoperative radicular pain completely resolved after surgery. In all 14 patients with CSA, deltoid muscle strength improved; in approximately 80% of these patients, there was either no muscle weakness or only slight weakness. The flexion angles and ROM significantly decreased at the time of the last follow-up examination (p = 0.0402 and 0.0196, respectively). No other items changed significantly.
The aforementioned surgical procedure was safely completed and the surgical outcomes were satisfactory for CSRM including CSA. The instability (the angulation and the vertebral slippage) did not significantly change after surgery. This procedure yielded outstanding results and should be considered an option for cervical laminoplasty in the future.
Masayuki Umeda, Kunihiko Sasai, Taketoshi Kushida, Ei Wakabayashi, Tokun Maruyama, Atsushi Ikeura and Hirokazu Iida
Modified cervical laminoplasty techniques have been developed to reduce postoperative axial neck pain and preserve function in patients with cervical spondylotic myelopathy (CSM). However, the previous studies demonstrating satisfactory surgical outcomes had a retrospective design. Here, the authors aimed to prospectively evaluate the 2-year outcomes of a modified cervical laminoplasty technique for CSM that preserves the paravertebral muscles.
Outcomes were analyzed for 40 patients (22 men and 18 women; mean age, 66.6 years; age range 44–92 years) with CSM who underwent C4–6 laminoplasty with C-3 and C-7 partial laminectomies or C-3 total and C-7 partial laminectomies and received hydroxyapatite spacers. Neurological, pain severity, and spinal radiographic evaluations were performed preoperatively and at 3, 6, 12, 18, and 24 months postoperatively. Plain radiography and MRI of the cervical spine were performed to evaluate the range of motion (ROM), sagittal alignment, and cross-sectional areas of the deep extensor muscles. The extent of bone–spacer bonding and bony union at the gutter was assessed by CT.
The mean preoperative Japanese Orthopaedic Association CSM score was 10.2, but it increased to 14.4 by 24 months after surgery. Eleven patients had axial neck pain preoperatively, but only 3 reported mild pain at 24 months, and in all 3 cases the pain was mild. The mean angle of lordosis was 11.7° preoperatively and 12.0° 2 years postoperatively. Although the ROM at the C2–7 levels was significantly reduced 3 months postoperatively, an increasing trend was observed up to 12 months, and 86% of the preoperative ROM was achieved by 2 years postoperatively. The mean paravertebral muscle cross-sectional areas were 833 ± 215 mm2 preoperatively and 763 ± 197 mm2 24 months postoperatively, but the difference was not statistically significant. The rates of bone–spacer bonding and bony union at the gutter were low during the early stages but increased to 90% and 93%, respectively, by 2 years after surgery.
The modified laminoplasty technique used in this study ensured very good neurological status and ROM after 2 years and was associated with low incidences of axial neck pain and serious complications. This simple and easy operative method could benefit future laminoplasty protocols.