2026 Volume 13 Pages 1-5
Cervical laminoplasty is a well-established surgical approach for managing various cervical spine pathologies, including cervical spondylotic myelopathy, spinal canal stenosis, and ossification of the posterior longitudinal ligament. Among the available laminoplasty techniques, the use of Hydroxyapatite spacers secured with screws is common for maintaining the expanded interlaminar space. However, one potential complication is screw back-out, which, although recognized, has rarely been documented in the literature. We present a rare case of delayed screw migration culminating in skin perforation in a 76-year-old woman who underwent cervical laminoplasty for cervical spondylotic myelopathy. During the index procedure, Hydroxyapatite spacers were placed and secured with screws into the lamina. Seven years postoperatively, gradual subcutaneous migration of the screw from the lamina of the fourth cervical vertebra was observed, ultimately resulting in complete skin penetration 9 years after the initial surgery. The patient underwent surgical removal of the protruding screw along with surrounding granulation tissue. The surgical site was thoroughly irrigated with copious saline, and the wound was closed primarily with sutures. Postoperative recovery was uneventful. Stitches were removed on day 11 after confirming complete wound healing. This case underscores an exceptionally rare but clinically significant late complication of cervical laminoplasty with Hydroxyapatite spacers -complete screw extrusion through the skin. To our knowledge, this is the first documented case of its kind. The prolonged asymptomatic nature of screw migration in this patient highlights the importance of long-term surveillance following laminoplasty, even in the absence of clinical symptoms, to detect hardware-related complications at an early stage.
Cervical laminoplasty is a widely adopted surgical technique for the management of cervical spine disorders such as cervical spondylotic myelopathy, spinal canal stenosis, and ossification of the posterior longitudinal ligament. Since the introduction of expansive open-door laminoplasty by Hirabayashi et al.,1) numerous modifications have been developed. These include alternative approaches for laminar opening, varied spacer designs to maintain the expanded interlaminar space, different fixation methods for spacers, and techniques for myoarchitectural reconstruction. When screws are used for spacer fixation, postoperative complications such as screw back-out may occur, although this is rarely reported. We describe an unusual case in which a screw used to secure an Hydroxyapatite spacer during cervical laminoplasty gradually migrated and ultimately protruded through the skin. In our institution, the double-door (French-door) laminoplasty technique is employed, with titanium screws used to fix Hydroxyapatite spacers in place. The present case illustrates an extremely rare occurrence of complete screw extrusion through the skin after this procedure, underscoring the need for long-term postoperative surveillance.
Patient: A 76-year-old woman
Past medical history: Hypertension, osteoporosis, and duodenal ulcer. Two years and four months after her initial cervical spine surgery, she underwent fenestration for lumbar spinal stenosis at the L3-L4 level. Eight years later, posterior fusion was performed at the same level.
Current medical history: Nine years prior to the current presentation, she had undergone cervical laminoplasty at our institution for cervical spondylotic myelopathy. The procedure involved C3 laminectomy, C4-C6 laminoplasty, and partial C7 laminectomy. Lateral gutters were created at the junction between the laminae and facet joints, followed by a midline split. The laminae were then opened using the double-door (French-door) technique. Following Takayasu's method,2) APACERAM® spacers (the original Takayasu model, modified by Kawanishi. HOYA Technosurgical Corporation, Japan) were placed in the expanded interlaminar spaces and fixed with titanium screws (Bear Medic Corporation, Japan) measuring 2.0 mm in diameter and 16 mm in length (Fig. 1A, B). At 2 years postoperatively, imaging demonstrated slight back-out of the screw placed in the right side of the C4 lamina (Fig. 2A). The screw remained in this partially backed-out position for several years without notable change. However, at 6.5 years postoperatively, radiographs confirmed complete screw back-out, although the screw remained close to the lamina (Fig. 2B). Given the absence of symptoms, conservative observation was chosen. Follow-up imaging at 7 years postoperatively revealed no further migration (Fig. 2C). At 8 year and 3 months, however, the screw was noted to have migrated into the muscle layer (Fig. 2D). By 9 years postoperatively, the patient presented with the screw protruding through the skin (Fig. 2E). The screw head was visible at the wound site, surrounded by black granulation tissue (Fig. 3). There was no purulent discharge. Computed tomography showed the gutter on the right side of C4 vertebra had fused (Fig. 4). The patient's temperature was 36.3°C. Laboratory findings showed a white blood cell count of 8,500/μL and a C-reactive protein level of 0.12 mg/dL, indicating no signs of systemic infection. Neurological examination revealed no new deficits in the extremities.
Post-operative computed tomography (CT).
A: 3D-CT. C3 laminectomy+C4-6 laminoplasty+C7 partial laminectomy was performed.
B: Axial image at C4 level. The screw was inserted completely.
3D: 3-dimensional.
Post-operative X-ray image.
A: 2 years after operation. Screw inserted at C4 level slightly back out.
B: 6.5 years after operation. Screw back out completely.
C: 7 years after operation. There was no obvious movement of the screw.
D: 8 years and 3 months after operation. The screw had moved into the muscle layer.
E: 9 years after operation. The screw protruded through the skin.
The screw head protruded through the skin.
Computed tomography taken when the screw protruded from the skin.
The gutter on the right side of C4 vertebra had fused.
The cervical range of motion (ROM) was 36.2 degrees before laminoplasty and 17.3 degrees after surgery. At 2 years postoperatively, when the screws began to loosen, it was 22.3 degrees. At 9 years postoperatively, when the screws protruded through the skin, it was 26.4 degrees. ROM was measured as the difference between the angles formed by the lower endplate of the second and seventh cervical vertebrae during flexion and extension on lateral radiographs.
Treatment and Outcome: Surgical removal of the protruding screw and surrounding necrotic tissue was performed. The wound was thoroughly irrigated with copious saline, and primary closure was achieved with sutures. Cefazolin sodium (1 g) was administered twice daily for 8 days postoperatively. Culture results from the removed screw and intraoperatively collected skin tissue were negative for bacterial growth. After complete wound healing, sutures were removed on postoperative day 11, and the patient was discharged home in stable condition.
Cervical laminoplasty is an established surgical option for treating various cervical spine disorders, including cervical spondylotic myelopathy, spinal canal stenosis, and ossification of the posterior longitudinal ligament. It is particularly effective for decompressing multilevel cervical spinal cord compressive lesions. The single-door technique (expansive open-door laminoplasty), introduced by Hirabayashi et al., was later complemented by the double-door (French-door) technique developed by Kurokawa et al.3) Both techniques remain in clinical use. We perform laminoplasty using the method reported by Takayasu et al.2)
Spacers placed in the expanded interlaminar space are available in various shapes and materials, with multiple fixation strategies. Commonly reported complications following cervical laminoplasty include C5 nerve palsy, axial neck pain, postoperative epidural hematoma, and hinge fractures of the opened laminae. However, screw-related complications in the fixation of Hydroxyapatite spacers are extremely rare. To date, only Liu et al.4) have described such events. In most cases, screw back-out after Hydroxyapatite spacers fixation does not lead to clinical sequelae, as complete screw extrusion is uncommon and the surrounding tissue lacks critical neural structures.3) This rarity, coupled with the frequent use of sutures instead of screws for spacer fixation in many institutions, likely explains the paucity of published reports. While cases of spacer dislodgement with suture fixation have been documented, screw-related skin perforation has not been previously reported.5-7) In the present case, we believe the initial loosening of the screw was caused by mechanical stress from micromovements between the Hydroxyapatite spacers and the lamina during cervical motion prior to complete bony fusion at the hinge. Reduced bone quality, possibly due to osteoporosis, may have contributed to fixation failure. As shown in Fig. 3, the screw ultimately migrated along the midline of the posterior neck incision, likely passing between bilaterally detached muscles. Repetitive cervical muscle contraction and stretching may have facilitated its progression from the spacer into the skin. A similar mechanism is seen in the spontaneous expulsion of foreign bodies such as wooden splinters or glass fragments from extremity tissues.
Notably, Liu et al.4) reported that screw loosening after open-door laminoplasty with titanium plates occurred in 5% of screws, with 68% loosening within the first 3 months and all cases within the first postoperative year. In contrast, screw loosening in our patient was first detected 2 years postoperatively-after expected hinge union-making the delayed onset unusual. Repetitive low-grade mechanical stress from cervical motion may have gradually caused the back-out. Cervical ROM decreased postoperatively and improved slightly until the second year when the screws began to loosen. Subsequently, the screw protruded from the skin, showing only a slight numerical improvement that appears to be within the margin of error. Based solely on the results of this case, it remains unclear whether changes in pre- and post-operative ROM influenced the screw backout.
Preventive measures for screw back-out include temporary cervical collar use until hinge union, although prolonged immobilization risks worsening axial pain and limiting cervical range of motion.8) Firm fixation can be ensured by bicortical screw placement, using larger-diameter screws if initial fixation is unstable, or opting for suture fixation when screw stability is questionable. The use of spacer designs that better align with lamina contours or screws with anti-loosening features may also reduce risk.
In our case, screw back-out began 2 years after surgery, with gradual migration leading to skin penetration over the following 7 years. Once screw back-out is detected, prolonged follow-up is essential. If migration toward the skin is observed, early surgical removal should be considered to prevent infection.
We describe an extremely rare case of screw back-out following cervical laminoplasty, in which a titanium screw used to secure an Hydroxyapatite spacer gradually migrated and ultimately protruded through the skin. Screw loosening was first detected 2 years after surgery, with progressive migration over the subsequent 7 years leading to skin penetration. This case highlights the importance of vigilant, long-term postoperative surveillance once screw back-out is observed. Early surgical intervention should be considered if the screw shows progressive migration toward the skin to prevent potential complications such as infection.
All authors have no conflict of interest.
