Traumatic anterior lumbosacral dislocation caused by hyperextension mechanism in preexisting L5 spondylolysis: a case report and a review of literature.

Of many reports referring to injury mechanism in anterior lumbosacral dislocation, there were none concerning hyperextension mechanism. We report a case of a 46-year-old man with preexisting L5 spondylolysis sustaining traumatic complete anterior lumbosacral dislocation. The operative findings, together with the radiologic findings, strongly suggested that the dislocation occurred by hyperextension mechanism. Open reduction was done by applying force of distraction with flexion using a rod and screw system, followed by the internal fixation from the L3 to S1 vertebrae and the postero-superior iliac spine. The lumbosacral dislocation was reduced to 77%. At the follow-up at 5 years after surgery, bony union was obtained and the patient could move with a wheelchair although the neurologic deficit in lower extremities observed preoperatively did not recover. Preexisting L5 spondylolysis was considered to increase the potential for anterior lumbosacral dislocation by additional force of compression with hyperextension. Posterior instrumentation using a rod and screw system was considered a useful method for reduction, decompression, stabilization, and fusion.

Effectiveness of multiple-level decompression in laminoplasty and simultaneous C1 laminectomy for patients with cervical myelopathy.

A retrospective study to investigate the relationship between the surgical levels and decompression effects was performed in patients with cervical myelopathy who had undergone Tension-band laminoplasty (TBL) with/without simultaneous C1 laminectomy. One hundred and sixty-eight patients (115 males, 53 females; age: 31-80 years, average 58.9 years; follow-up period: 12-120 months, average 20 months) were divided into three groups according to the range of the surgical levels: seventy-two patients in group A underwent TBL at the C2-C7 levels with C1 laminectomy; 60 patients in group B underwent TBL at the C2-C7 levels; 36 patients in group C underwent TBL at the C3-C7 levels. Neurological evaluation was performed by using the Japanese Orthopedic Association (JOA) scoring system. The alignment changes of the spinal column and the spinal cord were analyzed using pre- and post-operative roentgenograms and MRIs. The differences in the pre- and post-operative anterior subarachnoid spaces (D-ASAS), the spinal cord diameters (D-CORD), and the dural sleeve diameters (D-DURA) at the C1-C7 levels were also analyzed by using MRIs. The JOA scores improved in all groups. As for the spinal alignment, neither significant changes between pre- and post-operation in any group nor significant differences among the three groups were found. The lordosis of the cervical spinal cord was decreased in all groups. D-ASAS of group A was larger than that of group B at the C1-C5 levels (P<0.05), as were those of D-CORD and D-DURA at the C1-C2 and C4-C5 levels (P<0.05). D-ASAS of group A was larger than that of group C at the C1-C4 levels (P<0.05), as were those of D-CORD and D-DURA at the C1-C5 levels (P<0.05). In conclusion, laminoplasty including the C2-C7 levels with simultaneous C1 laminectomy was proven to allow the most posterior shift of the spinal cord within the widened dural sleeve at C5 or higher levels without significantly changing the spinal alignment.

Occipitocervicothoracic fixation using a hook and rod system for patients with rheumatoid cervical spine.

Abstract We retrospectively examined the outcomes of occipitocervicothoracic fixation using a hook and rod system for rheumatoid patients with cervical myelopathy in which decompression of the spinal cord and spinal fusion were performed simultaneously at multiple levels. There were 10 female patients with rheumatoid arthritis (ages 51-77 years, average 62.8 years; follow-up period 6 months to 3 years and 9 months, average 2 years and 8 months). Atlantoaxial subluxation was found in 5 patients, vertical subluxation in 4 patients, and subaxial subluxation in 8 patients. The progression of the disorder was assessed as class 4 stage 4 in 3 patients and class 3 stage 4 in 7 patients. The average time taken for surgery was 4 h 41 min, and the average volume of blood loss was 729 ml. There were no complications during surgery. One patient died of malignant lymphoma 1 month after surgery, and one patient died of heart failure 2 years and 3 months after surgery. The average Japanese Orthopaedic Association (JOA) score improved from 7.0 preoperatively to 9.5 postoperatively. Preoperative nuchal pain in 3 patients and difficulty in breathing on flexion of the cervical spine in 2 patients were improved after surgery. Good bony union was obtained in 9 patients. The exception being one patient who died of a disease unrelated to the surgery 1 month postoperatively. Occipitocervicothoracic fixation using a hook and rod system is an easy and safe procedure, and can facilitate not only good bony union, but also adequate decompression of the spinal cord with simultaneous laminoplasty because of the secure long fixation extending to the upper thoracic level and bilateral grafting of a considerable volume of bone.

Surgical anatomy of the nerves and muscles in the posterior cervical spine: a guide for avoiding inadvertent nerve injuries during the posterior approach.

STUDY DESIGN: An anatomic study investigated the cervical dorsal rami and major cervical paravertebral muscles. OBJECTIVE: To provide a detailed description of the cervical dorsal rami and important paravertebral muscles as a way of avoiding inadvertent injuries during the posterior approach. SUMMARY OF BACKGROUND DATA: No detailed anatomic studies of the nerves and the muscles in the posterior neck useful for the posterior approach have been reported previously. METHODS: Running courses of the cervical dorsal rami of spinal nerves and the morphology of cervical major paravertebral muscles were studied using 14 cadavers. In four posterior approaches of cervical laminoplasty, subcutaneous facial exits of cutaneous nerves and the running course of the right C3 medial branches around facet joint were exposed for observation of living anatomy. RESULTS: Every medial branch from the dorsal rami of the C3-C8 spinal nerves passed through an anatomic tunnel dorsolateral to the facet joint. The base of the tunnel was a bony gutter between neighboring facet joint capsules, and the roof was the tendon of the semispinalis capitis. In this tunnel, the medial branch had a little laxity in moving, and was assumed to be the most susceptible to iatrogenic injury during the operation. The semispinalis cervicis was composed with long muscle bundles. Each of these had only one or two innervating nerves from the dorsal rami of cervical spinal nerves. Cutaneous branches from the dorsal rami were found adjacent to every spinous process below the C2 spinous process in cadaveric studies. However, only two or three larger cutaneous nerves were discernible below the C5 or C6 spinous process in surgical approaches. CONCLUSIONS: With the posterior approach to the cervical spine, a precise knowledge of the cervical dorsal rami anatomy and the innervating patterns of the paravertebral muscles is necessary for avoidance of inadvertent injuries to the nerves.

Anatomically correct reduction and fixation of a Tile C-1 type unilateral sacroiliac disruption using a rod and pedicle screw system between the S1 vertebra and the ilium: experimental and clinical case report.

We have developed a new surgical technique for the treatment of Tile C-1 type sacroiliac disruption. We tried this procedure first in a cadaveric specimen and then applied it to a clinical case. We used the Texas Scottish Rite Hospital (TSRH) rod and pedicle screw system to insert one screw into the S1 vertebra without using an image intensifier and the other screw into the bone marrow of the ilium from the posterosuperior iliac spine. A straight rod was connected between the two screws by using a manipulator to attempt to reduce and fix the sacroiliac disruption. The combined pubic symphysis diastasis could be simultaneously reduced and fixed by using a plate through another incision, resulting in anatomically correct reconstruction of the pelvic ring. In this procedure, the alignment of the sacroiliac joint can be reversibly and directly changed during reduction and fixation. The sacroiliac joint can be strongly fixed because the screws can be freely inserted into the intact portion of the pelvis and the adjacent lumbar spine, if necessary. Good reduction is obtained because direct compression force is applied to the fracture site. The posterior and anterior procedures can be simultaneously performed under the same lateral position.