Freehand S2 Alar-Iliac Screw Placement Using K-Wire and Cannulated Screw: Technical Case Series

OBJECTIVE: Among the various sacropelvic fixation methods, S2 alar-iliac (S2AI) screw fixation has several advantages compared to conventional iliac wing screw. However, the placement of S2AI screw still remains a challenge. The purpose of this study was to describe a novel technique of free hand S2AI screw insertion using a K-wire and cannulated screw, and to evaluate the accuracy of the technique.METHODS: S2AI screw was inserted by free hand technique in sixteen consecutive patients without any fluoroscopic guidance. The gearshift was advanced to make a pilot hole passing through the sacroiliac joint and directing the anterior inferior iliac spine. A K-wire was placed through the pilot hole. After introducing a cannulated tapper along with the K-wire, a cannulated S2AI screw was installed over the K-wire.RESULTS: Thirty-three S2AI screws were placed in sixteen consecutive patients. Thirty-two screws were cannulated screws, and one screw was a conventional non-cannulated screw. Thirty out of 32 (93.8%) cannulated screws were accurately positioned, whereas two cannulated screws and one non-cannulated screw violated lateral cortex of the ilium.CONCLUSION: The technique using K-wire and cannulated screw can provide accurate placement of free hand S2AI screw.

Percutaneous S2-alar-iliac screw fixation for lower lumbar spondylodiscitis with no neurological symptoms in elderly patients: analysis of short-term curative effect / 介入放射学杂志

Objective To evaluate the short-term efficacy of percutaneous S2-alar-iliac screw (S2AIS) fixation for the treatment of lower lumbar spondylodiscitis with no neurological symptoms in elderly patients.Methods The clinical data of 28 patients of lower lumbar spondylodiscitis with no neurological symptoms,who were admitted to the Ward of Spine,Department of Orthopaedics,General Hospital of Shenyang Military Region,China,to receive percutaneous S2AIS fixation,were retrospectively analyzed.The operation was performed by the same surgeon for all patients.A total of 56 S2AIS fixation procedures were accomplished.The patients' age varied from 71 to 79 years old.The spondylodiscitis was located at IAL5 or L5-S1.After the treatment,the patients were followed up for a mean of 6.67 months.The mean operative time,the amount of intraoperative blood loss,the postoperative bed time,the average hospitalization days and the postoperative wound healing were documented and analyzed.The Oswestry score,visual analogue score,erythrocyte sedimentation rate,C reactive protein level were determined before operation as well as at one week and 6 months after operation,and postoperative CT was performed to check the loosening of internal screw fixation.The results were compared and analyzed.Results The mean operative time was (158.12±4.32) min,the average amount of intraoperative blood loss was (25.34±3.23) ml,the average postoperative bed time was (1.34±0.35) d,and the average hospitalization time was (7.29±1.34) d.Poor surgical incision healing was seen in only one patient,and the postoperative wound healing rate was up to 96.42％.Loosening of right S2AIS was detected in one patient,with the screw loosening rate being 1.79％.The Oswestry scores determined at one week and 6 months after treatment were 32.21 and 23.20 respectively,which were significantly different from the preoperative score (P＜0.05).The visual analogue scores determined at one week and 6 months after treatment were 2.17 and 1.25 respectively,which were significantly different from the preoperative score (P＜0.05).At one week and 6 months after treatment,the erythrocyte sedimentation rates were 15.32 mm/h and 14.56 mm/h respectively,and the C reactive protein levels were 7.89 mg/L and 8.90 mg/L respectively,both of which were significantly different from the preoperative ones (both P＜0.05).Conclusion For the treatment of lower lumbar spondylodiscitis with no neurological symptoms in elderly patients,percutaneous S2AIS fixation has certain advantages,such as less trauma,less blood loss,early postoperative ambulation,remarkable improvement of clinical symptoms,etc.with satisfactory short-term clinical efficacy.

Freehand S2 Alar-Iliac Screw Placement Using K-Wire and Cannulated Screw: Technical Case Series

OBJECTIVE: Among the various sacropelvic fixation methods, S2 alar-iliac (S2AI) screw fixation has several advantages compared to conventional iliac wing screw. However, the placement of S2AI screw still remains a challenge. The purpose of this study was to describe a novel technique of free hand S2AI screw insertion using a K-wire and cannulated screw, and to evaluate the accuracy of the technique. METHODS: S2AI screw was inserted by free hand technique in sixteen consecutive patients without any fluoroscopic guidance. The gearshift was advanced to make a pilot hole passing through the sacroiliac joint and directing the anterior inferior iliac spine. A K-wire was placed through the pilot hole. After introducing a cannulated tapper along with the K-wire, a cannulated S2AI screw was installed over the K-wire. RESULTS: Thirty-three S2AI screws were placed in sixteen consecutive patients. Thirty-two screws were cannulated screws, and one screw was a conventional non-cannulated screw. Thirty out of 32 (93.8%) cannulated screws were accurately positioned, whereas two cannulated screws and one non-cannulated screw violated lateral cortex of the ilium. CONCLUSION: The technique using K-wire and cannulated screw can provide accurate placement of free hand S2AI screw.