Use of intraoperative cell-salvage for autologous blood transfusions in metastatic spine tumour surgery: a systematic review.

Metastatic spine tumour surgery (MSTS) and metastatic musculoskeletal tumour surgery (MMTS) are associated with substantial blood loss. Allogeneic blood transfusion is the present method used to replenish this blood. Intraoperative cell salvage (IOCS) is a viable alternative, but is contraindicated in tumour surgery because of the risk of tumour dissemination. Use of IOCS-leucocyte depletion filter (LDF) allows removal of tumour cells from blood salvaged during oncological surgery. However, no reports exist on use of IOCS in MSTS or MMTS. We systematically reviewed studies on IOCS in oncological surgery to investigate whether sufficient evidence exists to support its use in MSTS or MMTS.

Solis cage (PEEK) for anterior cervical fusion: preliminary radiological results with emphasis on fusion and subsidence.

BACKGROUND CONTEXT: Recent literature has raised some apprehensions with regard to the usage of cervical cages. PURPOSE: Radiological review of cases performed at our institution with a novel cage made of polyetheretherketone (PEEK). STUDY DESIGN: Retrospective study. METHODS: A retrospective review of the first 15 consecutive cases of single-level anterior cervical interbody fusion using the Solis cage (PEEK material) for cervical spondylotic radiculopathy or myelopathy was performed. The follow-up ranged from 12 to 35 months (average 18 months). Anteroposterior and lateral radiographs were taken immediately after the surgery and at intervals of 3, 6, 12, and 24 months after surgery. Anterior disc height (ADH), posterior disc height (PDH), interbody height ratio (IBHR), distance between the posterior margin of the cage and the posterior wall of the vertebral body (D-CPW), and interbody angle (IBA) were measured on the lateral radiographs and compared. Fusion was assessed by examining for trabecular continuity, bridging of bone across the disc space, and sclerosis at the vertebral end plates on both sides. The parameters assessed were time for fusion, subsidence, segmental sagittal alignment of the operated segment, and presence/absence of migration of the cage. Data were analyzed using the Mann-Whitney nonparametric test. RESULTS: Fusion was evident at 3-6 months postsurgery in all cases except one (93.33% fusion rate at 6 months). At the last follow-up, fusion was maintained in all cases. The immediate postoperative ADH and PDH was significantly greater than the respective preoperative values and was maintained at the last follow-up though there was a significant amount of subsidence when the follow-up radiographs were compared with the immediate postoperative X-rays. The immediate postoperative IBHR was significantly greater than the preoperative IBHR, and was maintained at the last follow-up, but not statistically significant. The immediate postoperative IBA (lordotic angle) was greater than the preoperative IBA but was not statistically significant. The IBA at the last follow-up was lesser than the preoperative value but with no statistical significance. The IBA measured at the last follow-up was less than the value at the immediate postoperative period, but not statistically significant. There was no migration or extrusion of the cage at latest follow-up. CONCLUSIONS: The high fusion rate, low subsidence, stability provided by the cage, and facilitation of radiological assessment are the result of the physical properties of the PEEK material as well as the design of the cage.

Insertion torque profile during pedicle screw insertion of the thoracic spine with and without violation of the pedicle wall: comparison between cylindrical and conical designs.

STUDY DESIGN: Biomechanical study in human cadaveric thoracic spines. OBJECTIVE: To compare the insertion torque profile of cylindrical and conical screws with normal insertion tract, and with violation of the pedicle. SUMMARY OF BACKGROUND DATA: Previous studies revealed higher insertion torque for conical screws. No study has investigated the torque profile of both screws when there is violation of the pedicle. METHODS: The pedicle screws were inserted intrapedicularly (Type 1), violating the lateral cortex of the pedicle (Type 2), and violating the medial cortex of the pedicle (Type 3). Type 2 screws were further subdivided into those having contact with the lateral vertebral body (2a) and those without (2b). Type 3 screws were subdivided into those having contact with the medial pedicle wall (3a) and without (3b). RESULTS.: During initial insertion, the torque increased as they penetrated into the pedicles. With violation of the lateral cortex of the pedicle, insertion torque for the cylindrical screw decreased as the screw advanced anteriorly out of the pedicle. The insertion torque for the conical screw continued to increase at a constant rate after violation of the lateral cortex. With medial breach of the pedicle wall, torque profile of the conical screws remained the same as those inserted in the normal trajectory. There was a decline in the insertion torque for the cylindrical screws when medial violation of the pedicle wall occurred, the decrease being greater for Type 3b as compared with Type 3a screws. CONCLUSIONS: Surgeons may be unable to perceive the occurrence of medial or lateral breach of the cortex when inserting a conical screw. Surgeons inserting cylindrical screws with Type 3a violation may not be able to perceive a significant decrease in torque.