Abstract: A method of securing a rod to a receiver via a closure top. The receiver is configured to be used with a bone anchor and includes a pair of upright arms that define an open channel configured to receive the rod, a discontinuous helically wound receiver guide and advancement structure formed into the interior surfaces of the upright arms, and horizontally-elongated tool-engaging structures formed on the outer surface of the upright arms. The method further includes positioning the rod within the open channel of the receiver and securing the rod to the receiver by threadably advancing the closure top to secure the rod and within the receiver body of the receiver. The method further includes rotatably attaching a lower end of a tool to the receiver.

Abstract: A minimally invasive system for retraction, compression and distraction includes a tap having a shaft with threads and a head, a blade having a proximal end and a distal end and a base removably mountable to the proximal end. The tap is configured to form screw threads in a bone. The distal end is mountable to the head. The blade is pivotable relative to the head in a mounted configuration. The blade is configured to facilitate soft tissue retraction in the mounted configuration. The base is configured to manipulate the blade to retract and compress segments of the bone. The base is configured to provide distraction and/or compression using the provisional taps either directly or through the use of blades, insertion devices or tubes. The blades may be used to retract tissue and provide a visual field either independent or in conjunction with the provisional taps, insertion devices or tubes.

Abstract: A polyaxial bone anchoring device is provided comprising a bone anchoring element having a shank to be anchored in a bone and a head; a receiving part coupled to the shank and configured to pivotably receive the head, and having a channel for receiving a rod and a longitudinal axis; a pressure member configured to be positioned in the receiving part; a locking member insertable into the channel; wherein the pressure member has a deformable portion; and wherein, when the locking member is advanced into the channel in the direction of the longitudinal axis, the locking member in moveable from a position where it contacts the pressure member resulting in a load applied to the pressure member that clamps the head, to a position where the locking member contacts the pressure member such that the deformable portion is deformed and the locking member contacts the rod and clamps the rod.

Abstract: A receiving part for receiving a rod for coupling the rod to a bone anchoring element includes a receiving part body including a first end and a second end, and having a substantially U-shaped recess at the first end forming a channel for receiving the rod, and an accommodation space for accommodating a head of the bone anchoring element, the accommodation space having an opening at the second end for introducing the head; and a pressure element arranged at least partially in the accommodation space, the pressure element including a first section having a second recess for receiving the rod, and a second section having a flexible portion to clamp the head, the first section and the second section being fixed relative to each other, wherein said pressure element is insertable from the opening.

Abstract: A spinal implant comprises at least one bone fastener including a proximal portion configured for fixation with a first anterior cortical surface of a vertebra and a distal portion configured for fixation with a second cortical surface of the vertebra. The proximal portion is engageable with a surgical driver having a surgical navigation component that generates data for display of an image representing position of the spinal implant relative to the vertebra. The spinal implant can be employed with cervical, thoracic, lumbar and/or sacral regions of a spine. Systems, surgical instruments and methods are disclosed.

Abstract: Embodiments herein are generally directed to spinal implants for use in orthopedic stabilization assemblies. In some embodiments, these implants may be used in conjunction with laminoplasty or laminectomy procedures.

Abstract: A system to stabilize and guide the growth of the spinal column includes an elongated support member having a width and a length and a guiding connector having a bone connecting portion and a guiding portion. The bone connecting portion secures the guiding connector to a vertebrae and the guiding portion has a bearing element with a passageway adapted to receive the elongated support member. The bearing element permits relative sliding movement of the elongated support element in the passageway of the bearing element. The system may further include a bone fixation element has an elongated support member receiving channel, a locking mechanism and a bone anchoring portion. The bone anchoring portion secures the bone fixation element to bone. The locking mechanism secures the elongated support member in the channel. The guiding connector is moveable along the elongated support member to permit and control the growth of the spinal column along a predetermined path.

Abstract: Pedicle-based intradiscal fixation devices, systems, instruments, and methods thereof. An implant for stabilizing an inferior vertebra and a superior vertebra may include a first member and a second member moveably connected to the first member. The implant may have a first, initial insertion orientation and a second, final implantation orientation different from the first, initial insertion orientation. The first member may be configured to be inserted through a pedicle of the inferior vertebra and the second member may be configured to engage bone of the superior vertebra in the second, final implantation orientation.

Abstract: According to some embodiments, systems and methods of ultrasonic detection of implantable medical device distraction are provided. The system includes a first elongate member and a second elongate member. The first elongate member has a first end that is configured to be attached to a first location on the skeletal system of a subject, a second end, and at least one landmark identifiable using ultrasound. The second elongate member has a first end that is movably coupled to the second end of the first elongate member, a second end configured to be attached to a second location on the skeletal system, and at least one landmark identifiable using ultrasound. Movement of the first elongate member in relation to the second elongate member causes a corresponding movement of the at least one first landmark in relation to the at least one second landmark which can be detected using ultrasound.

Abstract: Systems and methods for en bloc derotating a spinal column are provided. In one exemplary embodiment, the method can include manipulating first and second frames coupled respectively to a first set of vertebrae and a second set of vertebrae to derotate the first and second sets of vertebrae relative to one another, and subsequently locking a linkage assembly coupled respectively to the first and second frames to maintain the first and second sets of vertebrae in a derotated position.

Abstract: Pedicle-based intradiscal fixation devices, systems, instruments, and methods thereof. An implant for stabilizing an inferior vertebra and a superior vertebra may include a first member and a second member moveably connected to the first member. The implant may have a first, initial insertion orientation and a second, final implantation orientation different from the first, initial insertion orientation. The first member may be configured to be inserted through a pedicle of the inferior vertebra and the second member may be configured to engage bone of the superior vertebra in the second, final implantation orientation.

Abstract: A bone fastener includes a head including a first receiver defining an implant cavity and a distal portion defining a plurality of adjacent grooves. The head further includes a second receiver defining an implant cavity. A first resilient member is configured for disposal within the plurality of adjacent grooves and a second resilient member is configured for disposal within the plurality of adjacent grooves. A shaft is aligned with the first receiver and is configured to engage tissue. Systems, surgical instruments, spinal constructs, implants and methods are disclosed.

Abstract: A modular pivotal bone anchor assembly includes a receiver having a central bore with a locking region adjacent a bottom opening, an expansion region above the locking region, an interference abutment surface above the expansion region, and a retaining groove above the interference abutment surface. The assembly also includes a bone screw having a head uploadable through the bottom opening, an insert positionable within the central bore with protruding engagement structures received within the retaining groove, an upper open ring positionable below the insert, and a lower open ring positionable below the upper open ring for capturing the head within the locking region, after which the upper open ring occupies the expansion region and the insert is downward deployed by tooling, with the engagement structures moving out of the retaining groove and into an overlapping arrangement with the interference abutment surface to inhibit upward movement.

Abstract: Systems, methods, and devices for securing a sublaminar band are provided. A sublaminar band clamp system may include a first locking mechanism, a second locking mechanism, and a body. The body may include a first portion comprising a first passage, wherein the first locking mechanism is disposed within the first passage. The body may further include a second portion comprising a second passage, wherein the second locking mechanism is disposed within the second passage. A third passage may extend across the body and may be in fluid communication with the second passage. An opening may be positioned between the first and second portions, and the opening may be in fluid communication with the first passage.

Abstract: Devices and methods for enhancing the effectiveness of spinal stabilization, and particularly that of cervical spinal stabilization, are provided herein. More specifically, methods and systems are disclosed for effectively positioning occipital plates and spinal fixation assemblies within target vertebrae, while also reducing any associated patient trauma (e.g., muscle stripping, tissue damage, etc.). The systems and methods can utilize trans-lamina delivery of the spinal fixation assemblies to allow for the positioning of the fixation elements along the midline of the patient's spine.

Abstract: To achieve in vivo repair of severed mammalian nerve tissue, a system can be employed to induce distraction neurogenesis. At least a portion of the system can be anchored at an injury site, such as between distal and proximal nerve ends. The system can be attached to the proximal nerve end and can place the nerve under micro-tension for an extended period of treatment. The system may also deliver medication or treatment to encourage neurogenesis and to reduce pain in the subject receiving treatment. After the course of treatment, the device can be removed from the injury site, and the nerve ends rejoined.

Abstract: The invention discloses a modular surgical bone screw assembly having a threaded base portion and a screw head adapted to attach a variety of structures to bone. The features of the screw include a modular design for the assembly that separates the function of anchorage to the recipient bone to one of the modules of the device (threaded portion) from the other function of attaching another element (such as bone block, membrane, orthodontic wires, elastics etc) to a second module (the screw head). The design also allows the head to be exchanged after the implant has been placed.

Abstract: A coupling device for coupling a rod to a bone anchoring element includes a receiving part with a head receiving portion for receiving a head of the bone anchoring element, a rod receiving portion for receiving the rod, a downwardly facing surface, and an upwardly facing surface below and monolithically formed with the downwardly facing surface, and a locking member movable relative to the receiving part from a first position where the head is insertable into the head receiving portion to a second position where the head is prevented from being removed from the head receiving portion. At least part of the locking member is held to the receiving part between the downwardly and upwardly facing surfaces, and wherein the receiving part and the locking member are only separable from one another by permanently deforming or damaging at least one of the receiving part or the locking member.

Abstract: A method for securing an elongate rod to a bone anchor with a receiver and a threaded plug. The receiver includes a channel configured to receive the elongate rod, and a helically wound receiver guide and advancement structure formed into the interior surfaces of the receiver. The threaded plug is configured for positioning within the channel to secure the elongate rod to the receiver in a locked configuration, with the threaded plug having an outer surface with a mating continuous helically wound guide and advancement structure configured for rotatable engagement with the receiver guide and advancement structure.

Abstract: An anchoring system for a spinal support rod. The anchoring system includes a self-tapping orthopedic fastener that is bored through the ilium via a lateral incision and a mounting receiver that is positioned to receive the orthopedic fastener via a posterior incision. The orthopedic fastener may be implanted from a lateral approach or a posterolateral approach. The mounting receiver may be implanted from a posterior or superior posterior approach.

Abstract: A transpedicular anchoring screw including a screw body having a first helical thread having:includes a proximal portion, having notched portions inscribed within notched angular sectors and separated by separation portions inscribed within separation angular sectors, where, over a screw pitch, a ratio between the sum of the measurements of the separation angular sectors and the sum of the measurements of the notched angular sectors is between 50% and 150%. The anchoring screw also includes a distal portion, having notched portions inscribed within notched angular sectors and separated by separation distal portions inscribed within separation angular sectors, where, over a screw pitch, a ratio between the sum of the measurements of the separation angular sectors and the sum of the measurements of the notched angular sectors is between 0% and 10%.

Abstract: A system for reducing deformities of the vertebrae in the spine includes a first reduction assembly, a second reduction assembly, and a reduction drive assembly. The first reduction assembly is configured for attachment to a first reduction tower that attaches to a first vertebra. The second reduction assembly is configured for attachment to a second reduction tower that attaches to a second vertebra. The reduction drive assembly includes an arcuate rack gear operably coupling the first reduction assembly to the second reduction assembly to translate the first reduction assembly relative to the second reduction assembly along an arcuate path in a first plane.

Abstract: A system includes a screw tower, an instrument, and a housing. The instrument includes a driver shaft extendable longitudinally through the screw tower, and a threaded sleeve mounted on a proximal portion of the driver shaft. The housing includes one or more retention members coupleable to the screw tower, and a threaded button threadably coupleable to the threaded sleeve. The threaded sleeve is rotatable about a longitudinal axis to urge the driver shaft longitudinally relative to the screw tower.

Abstract: A low-profile offset-type spinal fusion device includes a first screw, a connection base, a nut and a compression part. The first screw has an external thread and a flange. The connection base includes a penetration part and a connection part disposed no higher than the penetration part, and can sleeve the first screw through a first hole of the penetration part to contact the flange with opposite ends of the first screw protruding out of the first hole. The nut, used to engage the first screw, has a bottom surface to contact against the penetration part. When the first screw is installed by penetrating the first hole, the nut and the flange are located to opposite ends of the first hole. The compression part is to screw into a cavity of the connection part for depressing a connecting bar tightly in the cavity.

Abstract: This invention relates to devices and methods for the electrochemical removal of unwanted deposits in humans and animals, or for prevention of bone loss following implantation of metal and other surgical materials in the body. A selected voltage is applied using direct current and an electrode to discourage growth or remove deposits, including bone spurs, and may be applied using microneedles in skin contact with a human or animal.

Abstract: A bone fixation assembly may include an elongate fixation member and a flexible tensioning element. The elongate fixation member may include a central longitudinal axis, a distal portion couplable to a first bone fragment of a bone, and a proximal portion couplable to a second bone fragment of the bone to provide fixation of the second bone fragment relative to the first bone fragment. The flexible tensioning element may be couplable to the proximal and distal portions of the elongate fixation member to secure the elongate fixation member to the bone. The flexible tensioning element may be configured to span a bone fracture intermediate the first bone fragment and the second bone fragment to preload the bone fracture in compression to resist tensile force imparted across the bone fracture, thereby maintaining fixation of the first bone fragment relative to the second bone fragment.

Abstract: An ultrasonically assisted clamping system and method for extending a spinal support rod system to additional vertebrae of the spine. A clamp assembly and a receptacle assembly securely couple an additional extension rod to an existing spinal support rod. Various embodiments further include an ultrasonic assist for cutting through tissue that may be present in the vicinity of the existing spinal support rods. In some embodiments, the clamp assembly is configured to augment the ultrasonic aspect of the system. The system cuts through and locally removes tissue from and proximate to the spinal support rods where the clamp assembly is to be mounted, without the need for a separate surgical procedure for removing the tissue prior to implantation, thereby providing a secure clamping of the newly implanted extension rod to the existing base spinal support rod.

Abstract: A bone fixation assembly includes a plurality of bone fixation elements that each include a bone anchor configured to be implanted into underlying bone, such as a vertebra. Each bone anchor is received in an anchor seat, and the anchor seats are joined by a fixation rod so as to operatively couple and fix the position and orientation of the vertebrae relative to each other. The bone anchor is free to rotate relative to the anchor seat, and is also free to pivot in a desired direction relative to the anchor seat.

Abstract: A polyaxial bone anchor has a locking element shaped and configured to allow an anchoring member (e.g., a screw or hook) to polyaxially rotate at large angles about a central axis of the bone anchor before compression locking the anchoring member within an anchor head.

Abstract: Connector assemblies, systems, and methods thereof. An articulating connector has a first end that clamps to a first rod in an existing construct and a second end having a second end that clamps to a second rod in a new construct or such that the new construct can be extended from the existing construct. In the case of different sized constructs used in different areas of the spine, an articulating connector has a first end that clamps to a first rod in a new construct having rods of a first size and a second end having a second end that clamps to a second rod in a new construct having rods of a second size. The clamping portions are capable of translating and rotating with respect to each other.

Abstract: A medical implant assembly including a receiver and a fastener. The receiver having helically wound thread extending up to a top surface thereof. The fastener having an axis of rotation and a continuously helically wound thread form. The continuously helically wound thread form having a start structure and an upper loading surface extending between a root and a crest of the continuously helically wound thread form. The start structure having a leading face extending below the upper loading surface. The leading face including a partial curvate surface extending between the root and the crest. The start structure being configured as a single lead start structure and a dual lead start structure.

Abstract: A pedicle screw implant construct kit, comprising at least one pedicle screw, at least one collar comprising a recess for receiving a rod, the collar configured to be coupled to a head of the pedicle screw, an elongated rod for connecting the collar to one more additional collars to couple between the pedicle screw and one or more additional screws, and a locking ring sized to be positioned over at least a distal portion of the collar to restrain relative movement of the screw head and rod by exerting radial compression force onto the collar. In some embodiments, the components of the kit are comprised of carbon reinforced composite material, optionally with no radiation blocking material. In some exemplary embodiments of the invention, the kit includes two locking rings on a collar, optionally both below the rod.

Abstract: Fiber-reinforced polymer matrix composite material bone screws having threads surfaced with a metallic layer are described. In some embodiments, the metallic layer comprises a plurality of anchors placed to engage with the composite material and resist shearing when the bone screw is inserted or removed.

Abstract: Disclosed herein are a spinal fixation assembly and method to provide adequate rigidity and support for a vertebral column without requiring additional pedicle screws and spinal rods. The spinal fixation assembly includes a spinal rod loop with multiple sides configured to be attached to a vertebral body with two or more pedicle screws. Each pedicle screw is adapted to fit at various locations along the spinal rod loop.

Abstract: A vertebral body replacement device, dimensioned for implantation between a first and second vertebral bone is described. The vertebral body replacement device includes a superior endcap, an inferior endcap and a central core between the superior and inferior endcaps. The vertebral body replacement device further includes a fusion aperture extending through the superior and inferior endcaps and central core. The vertebral body replacement device is made of radiolucent material and can be implanted from a lateral or anterior approach to the spine.

Abstract: A spinal screw assembly includes a bone screw having a head with a rounded outer surface and an anchor portion for fixation to the bone. The assembly also includes a body member defining an internal cavity communicating with a bottom surface of the body member through a lower opening, with an interior surface adjacent the lower opening configured to engage the rounded outer surface of the head of the screw, and an upper portion defining a channel for receiving a fixation rod. The screw head is configured for uploading into the cavity of the body member through the bottom opening until the rounded outer surface enters into pivotal engagement with the interior surface of the internal cavity, with the screw extending downwardly through the lower opening, so as to allow for variable angular movement of the bone screw relative to the body member prior to locking the spinal screw assembly with a closure.

Abstract: A modular head polyaxial pedicle screw assembly has a pedicle bone screw, a tulip, a split locking ring and a saddle. The screw has a head and a threaded shank. The split locking ring has a split ring body with one or more positioning tabs extending from a first surface of the split ring body. The split ring locking ring is configured to be placed internal of the tulip positioned in a recess, groove or undercut of an inner surface of the tulip. Upon assembly of the pedicle screw into the tulip, at least a maximum diameter of the head is positioned above the recess, groove or undercut allowing the split locking ring to be inserted into the recess or groove thereby securing the pedicle screw inside the tulip wherein the head of the pedicle screw abuts the one or more positioning tabs.

Abstract: An osteosynthesis device for the treatment of the spine is disclosed having a fork head which is U-shaped in a side view, and which fork head, in the proximal direction, has two fork legs with an internal thread and in which a connecting rod can be received, and a grub screw is passed through the internal thread, and the fork head is detachably connected to a bone anchor. The bone anchor is pivotably mounted in the ball seat of the fork head, wherein the fork head in the ball seat area has slots open towards the distal side and thereby at least one deflectable leg is formed.

Abstract: A construct may include a connector having a first body portion and a second body portion rotatably coupled to another. A first implant cavity may be defined, at least partly, by at least two threaded arm portions defining a first axis between the at least two threaded arm portions. The first implant cavity may include a first receiving cavity configured to adjustably orient a first rod in a plane substantially perpendicular to the first axis, and the second implant cavity may include a second receiving cavity configured to orient a second rod. In some embodiments, the threaded arm portions are configured to receive a first set screw such that when the first set screw is fully tightened along the first axis the first rod is fixed relative to the first body portion in a direction extending substantially parallel with the plane.

Abstract: A bone anchoring device includes a receiving part having a first end with an end surface, a second end, a recess at the first end for receiving a rod, and a flexible head receiving portion at the second end for pivotably holding a head of a bone anchoring element, and a clamping ring positionable around the head receiving portion and movable from a first position where the head is pivotable relative to the receiving part, to a second position where the clamping ring exerts a radial force onto the head receiving portion to lock the head. The receiving part further includes a first engagement structure at or adjacent the end surface extending radially outwardly from an outer surface of the receiving part, such that a width of the receiving part including the first engagement structure is at least as wide as a maximum width of the clamping ring.

Abstract: Treatment of spinal irregularities, including, in one or more embodiments, derotation apparatus and systems that can be used to reduce the rotation of vertebral bodies. Derotation apparatus that may comprise a tube assembly comprising an inner sleeve and an outer sleeve disposed over the inner sleeve. The inner sleeve may have a distal end for attachment to an implant. The tube assembly may further comprise a handle assembly. The tube assembly may further comprise a ball joint assembly disposed between the tube assembly and the handle assembly. The ball joint assembly may comprise a ball joint configured for attachment to a coupling rod. The ball joint assembly further may comprise a reducing extension below the ball joint, the reducing extension being sized to fit in a central bore of the inner sleeve. Orthopedic fixation devices comprising a ball joint are also disclosed.

Abstract: A polyaxial bone screw assembly includes a receiver having an axial bore with a pair of opposed downward-facing shoulder surfaces pre-formed therein between a discontinuous guide and advancement structure and a bottom opening, a shank having a capture portion configured for positioning into the axial bore with the shank extending downward through the bottom opening, and a pressure insert having upward-facing contact surfaces. The pressure insert is configured for positioning into the axial bore of the receiver into a first position and for subsequent rotation about a longitudinal axis by a tool into a second position that locates the upward-facing contact surfaces at least partially under the downward-facing shoulder surfaces to inhibit the pressure insert from moving upwardly within the axial bore.

Abstract: Systems and methods for reducing the risk of PJK, PJF, and other conditions are disclosed herein. In some embodiments, a longitudinal extension can be added to a primary fixation construct to extend the construct to one or more additional vertebral levels. The extension can be attached to a first attachment point, such as a bone anchor implanted in a vertebra that is superior to the primary construct. The extension can also be attached to a second attachment point, such as a component of the primary construct or an anatomical structure disposed inferior to the first attachment point. The extension can be more flexible than the primary construct and/or can limit motion to a lesser degree than the primary construct, thereby providing a more-gradual transition from the instrumented vertebrae to the natural patient anatomy adjacent thereto. The extension can be placed with little or no soft tissue disruption.

Abstract: The present invention relates to a connector for simultaneously fixing a screw head and a rod, wherein the connector can be firmly fixed to a screw head and a rod, which have been surgically inserted, without requiring disassembly of the screw head and the rod, thus minimizing damage to the affected region. The connector may comprise: a connecting block in which a head accommodation hole portion is formed on one side thereof to be able to accommodate at least a portion of a screw head installed in a vertebral body, and a rod accommodation groove portion is formed on the other side thereof to be able to accommodate at least a portion of a rod that extends from the screw head; a connecting rod formed in a shape extending from the connecting block; and a fixing device that fixes the connecting block to the screw head.

Abstract: The present invention is generally directed to orthopedic fixation devices that comprise a pre-assembled double headed tulip assembly, having two tulip elements to receive rods, wherein the assembly may be configured to receive a bone fastener in at least one of the tulip elements. At least one of the tulip elements may comprise a saddle and a ring to attach the double headed tulip to a bone fastener.

Abstract: A ratcheted spinal device including a variable-length member including a ratchet mechanism that has an operative configuration that allows a change in length of the variable-length member in one direction and prevents a change in length of the variable-length member in an opposite direction, wherein the variable-length member includes polyaxial-joint attachment members for attachment to bone, which permit pivoting movement of the attachment members about more than one pivoting axis.

Abstract: The present invention provides a sacral-iliac plate having an iliac portion with a first screw hole for receiving a first fastener to secure the iliac portion to the iliac bone. A sacral portion integrated monolithically with the iliac portion is also provided with a second and third screw holes for receiving second and third fasteners to secure the sacral portion to the sacral bone. The sacral portion also includes a tulip for receiving and securing a spinal rod.

Abstract: A polyaxial bone anchoring device is provided including a bone anchoring element (1) comprising a head (3) and a shank (2); a receiving part (4, 4?) for receiving a rod (100) for coupling the rod to the bone anchoring element, the receiving part comprising a first end (4a), an opposite second end (4b) and a central axis (C) extending through the first end and the second end, and a channel (9) for receiving the rod and an accommodation space (11) for receiving the head; a pressure element (6, 6?) arranged in the receiving part and configured to exert pressure onto the head; wherein the pressure element (6) comprises flexible sections (66a, 66b) facing away from the head (3), characterized in that the flexible sections (66a, 66b) comprise a free end portion (69a, 69b) with respect to the central axis (C) that cooperates with an inclined surface portion (15a, 15b) of the receiving part (4) such as to hold the pressure element (6) in a position in which it exerts a pre-load onto the head before the head is lo

Abstract: A connection assembly configured to securely connect a spinal implant to a bone anchor. In particular, a variable angle connection assembly that is able to securely connect the spinal implant to the anchors even when there is a variance in the angle and position of the anchors with respect to the spinal implant. Furthermore, a connection assembly that will not inadvertently lock the components of the connection assembly preventing the relative movement of the components.

Abstract: This disclosure describes example embodiments of rod reduction instrumentation and other rod and vertebrae manipulation instruments. The rod reducers can be used during the installation of a rod based surgical fixation system to help urge the rod into the fixation anchors. The reducers described provide various configurations delivering large reduction distance capabilities, strong controlled reduction coupled with an ability to quickly advance the reducer if desired, and reduction of bulk through the surgical corridor.