Abstract:
Embodiments relate to systems and methods for a cranial implant assembly adapted for insertion during a craniectomy procedure. In aspects, the inventive cranial implant assembly can contain a peripheral attachment member for attachment to the edge of a skull opening, as well as an articulated spanning member that over-arches and holds a cover in place over the opening. The articulated spanning member contains a central implant fastened or connected to a swollen dura in the skull opening. As swelling of the dura subsides, tension is exerted on guidewires in both the spanning member and cover to draw those constructs into a rigid state. The tips of the spanning member can gradually approach the peripheral attachment member, and register into place using a locking mechanism, such as a pair of opposing magnets. As a result, only one surgical operation or procedure Is required to both perform a craniectomy and implant a supporting assembly for eventual skull regeneration.

Description:
CROSS REFERENCE RELATED APPLICATION 
     This patent application claims priority to U.S. Provisional Application Ser. No. 61/369,403, filed Jul. 30, 2010, by the same inventor herein, which provisional application is incorporated in its entirety by reference herein. 
    
    
     FIELD 
     The present teachings relate to medical devices, and more particularly, to an initially non-rigid cranial implant introduced immediately during a craniectomy procedure that is capable of adapting to the shape of a displaced brain and of transitioning during the normalization of brain shape to a rigid state to protect the skull opening resulting from the procedure. 
     BACKGROUND OF RELATED ART 
     Several medical conditions including surgical interventions and trauma can lead to increasing intracranial pressure. These conditions include, but are not limited to: “malignant” cerebral infarction (stroke), brain tumors, epilepsy surgery, and craniosynostosis (congenital cranial anomalies), and brain injury trauma. In the case of brain injury trauma and/or strokes, these medical conditions can lead to a very dangerous effect of causing swelling or edema of brain matter and the enveloping dura within the confines of the cranium. The increased intracranial pressure caused by these conditions is be associated with serious complications including bruising or other damage to brain tissue, delirium, loss of consciousness or cognitive functions, secondary cerebral ischemia or infarctions, brain herniation and possibly death, if left untreated. This situation typically can only be effectively treated by surgical removal of a portion of the cranium (craniectomy) to allow room for the brain to expand and the release of cerebrospinal fluid to reduce the increased pressure. 
     In the field of treatments for traumatic brain injury (TBI), the current practice in managing acute cases of medically uncontrolled brain swelling is to perform an emergency craniectomy. In this surgical procedure, a flap of cranium is removed from the patient&#39;s cranium in order to provide relief to intracranial pressure and reduce the risk of the aforementioned serious or fatal complications. In the established course of treatment, the initial craniectomy producing the cranial opening is followed by a period of intensive rehabilitation. During the entire recovery period, the cranium remains open, and must be shielded by protective head devices or coverings, and the patient&#39;s activities may be significantly restricted. The patient also runs a significant risk of infection and other post-surgical problems. 
     One serious problem that can arise during the post-operative period is the so-called Syndrome of the Trephined. This condition results from the sinking of the dura within the cranial opening due to the negative intracranial pressure relative to the atmospheric pressure which, induces derangements of cerebrospinal fluid flow, cerebral blood flow and brain metabolism, leading to psychological and/or physical deficits in the patient during the recovery period. Once the cranial opening is covered through a separate, later-stage procedure (cranioplasty), documented cases exhibiting the Syndrome of the Trephined have shown a reversal of these deficits with varying rates of improvement. However, the prevailing practice for performing a cranioplasty is to wait for an average of six months or longer after the emergency craniectomy before repairing the cranial opening. 
     The traditional approach of performing a two-staged procedure of an initial emergency craniectomy followed by a later cranioplasty can be attributed in part to a landmark study carried out by Rish et al. (see Rish, et al., Neurosurgery, 4:381-385, 1979) showing that a shorter time from craniectomy to cranioplasty leads to a poorer outcome. A closer examination of this study by other authors (see Carvi Y, et al., 2006 and Liang et al., 2007, below) however, showed that the cases in the Rish study only pertained to penetrating or open head injuries, ignoring cases of closed (non-penetrating) head injuries that needed decompressive craniectomies as well. In fact, these authors subsequently (see Carvi Y, et al., Neurol Res 28:139-144, 2006; Liang et al., J Craniofac Surg 18:526-532) reported good outcomes after early cranioplasty for non-penetrating head injuries. 
     Other scientific studies further support performing cranioplasties early after an emergency craniectomy. Data on wartime cranioplasty complications observed during the 2003-2008 Iraq-Afghanistan conflict period (see Stephens F L, et al., Neurosurgical Focus/Journal of Neurosurgery 28(5), 2010) show that the majority of infected cranioplasty cases occurred during a delayed period (90-270 days from injury/craniectomy). Furthermore, multivariate analyses cited the presence of cerebrospinal fluid leaks and repeated operations as the main independent risk factor for the development of craniotomy (brain operation) infections, and not the craniectomy-to-cranioplasty waiting period per se (see Korinek A M et al., Br. J Neurosurg 19:155-162, 2005 and Cheng Y K, et al., J Clin Neurosci 15:1115-1119, 2008). 
     Further evidence of the benefit of performing cranioplasty earlier after an emergency craniectomy is found from the analysis of craniotomies. In cases where the head-injured require the evacuation of hematomas (bleeding), immediate reinsertion of the skull flap (osteoplastic craniotomy) may be allowable if the result is a quiescent brain (non-edematous). When the intended skull flap has undergone multiple fracture sites and is deemed not to be viable by the neurosurgeon, the skull flap is replaced by commercially available cranioplasty materials (cranioplasty for craniotomies). Wartime data on cranioplasties done for craniotomies analyzed in the same study cited above (see Stephens F L, 2010) show a significantly lower infection rate, suggesting that the period when a cranioplasty procedure can expect the least infection rate would be during the time of the first procedure itself (initial craniotomy or craniectomy). 
     It follows that, for head injuries requiring an emergency craniectomy due to an edematous (swollen) brain, the optimal period for performing cranioplasty would be during the initial craniectomy. However, all currently available cranioplasty constructs, being rigid, are designed for a late-staged and/or delayed cranioplasty procedure and none are designed to accommodate the initial brain bulging and adapt to the brain movement until the brain contour (and swelling) could normalize. Despite evidence to the contrary and due to the absence of a cranioplasty construct for immediate application after emergency craniectomy, the prevailing practice of a delayed cranioplasty for those craniectomized head-injury patients persists. 
     It may be desirable to provide systems and methods for a cranial implant assembly adapted for insertion during craniectomy procedure, which, among other advantages, provide the ability to relieve swelling of the brain and dura after a brain trauma or injury by way of a craniectomy, while providing the opportunity to concurrently introduce a cranial implant construct or assembly, during the same initial procedure, with no second-stage surgery required. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings and together with the description, serve to explain the principles of the present teachings. In the figures: 
         FIG. 1  illustrates side view of an overall surgical site in which reparative skull procedures using the inventive cranial implant assembly can take place, according to embodiments of the present teachings; 
         FIG. 2  illustrates an overall cranial implant assembly in a top view, according to various embodiments of the present teachings; and 
         FIG. 3  illustrates a side view of the cranial implant assembly of the present teachings undergoing a displacement due to recession of the patient dura, according to various embodiments; 
         FIG. 4A  illustrates a top view of a set of interdigitating subunits for a cover of the cranial implant assembly, according to various embodiments; 
         FIG. 4B  illustrates a side view of a set of interdigitating subunits for a cover of the cranial implant assembly, according to various embodiments; 
         FIG. 5A  illustrates a side view of a magnetic locking mechanism that can be used to lock an articulated spanning member and peripheral attachment member, according to various embodiments; 
         FIG. 5B  illustrates a diagram of sizing and other computations that can be carried out, according to various embodiments of the present teachings; 
         FIG. 6  illustrates aspects of a cranial implant assembly, according to further embodiments, 
         FIG. 7  illustrates conventional craniectomy treatments that have been used in connection with cases of hydrocephalus; and 
         FIG. 8  illustrates a cranial implant that can be used in connection with the treatment of cases of hydrocephalus, according to various embodiments. 
     
    
    
     SUMMARY 
     Embodiments of the present teachings relate to systems and methods for a cranial implant assembly adapted for insertion during a craniectomy procedure. More particularly, embodiments relate to an advanced cranial implant assembly which is capable of being introduced during the same surgical operation, procedure, or intervention as the craniectomy procedure performed to relieve pressure on swollen brain tissue or performed to correct a cranial malformation. The cranial implant assembly achieves a single-operation capability by having the ability to be introduced in an non-rigid state, and then to transition to a rigid overall state as the affected brain and/or dura returns to a normal shape. 
     These and other embodiments described herein address the various noted shortcomings in known cranial implant technology, and provide a physician, patient, or others with an enhanced treatment approach for TBI or other skull syndromes, deformities, and/or injuries in which both craniectomy and cranioplasty stages can be performed within a single or simultaneous surgical operation, procedure, or intervention. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to exemplary embodiments of the present teachings, which are illustrated in the accompanying drawings. Where possible the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       FIG. 1  illustrates a schematic diagram of a surgical site  100  in which systems and techniques according to the present teachings can be practiced. As shown, the surgical site  100  can comprise the head and/or skull area of a patient, in which the skull  102  of a patient is desired to be operated upon to produce a skull opening  126  exposing the underlying dura  104 . The skull opening  126  can be produced using known techniques for performing a craniectomy, and therefore reduce the swelling, edema, inflammation, and/or pressure on the brain  130  and/or the dura  104  encapsulating the brain  130 . In other instances, the skull opening  126  can be caused by a TBI itself. 
       FIG. 2  illustrates a top view of a cranial implant assembly  128  according to aspects of the present teachings. In aspects, the cranial implant assembly  128  can, in general, be inserted or introduced in the area of the skull opening  126  as part of a concomitant cranioplasty procedure that can take place simultaneously with the craniectomy used to produce the skull opening  126 . As used herein, two or more procedures or actions performed “simultaneously” means procedures performed at the same time, at closely separated times, and/or during the same overall surgical operation, procedure, and/or intervention. In aspects, “simultaneously” can refer to craniectomy, cranioplasty, and/or other procedures of actions performed within 24 hours of each other, or procedures separated by smaller or larger intervals of time. 
     In embodiments as shown, the cranial implant assembly  128  can, in general, comprise a number of components, elements, or constructs which cooperate to provide an expansile, elastic, semi-rigid, or flexible protective structure over the skull opening  126  during an initial period after the opening of the skull opening  126 . As used herein, “semi-rigid” means any state less rigid than a state of full or maximally attainable rigidity. The cranial implant assembly  128  can, however, retain the ability to gradually transition to a rigid state, as the swelling of the brain  130  and/or dura  104  subsides during the post-operative phase. 
     In aspects as shown, the cranial implant assembly  128  can comprise generally shallow hemispherical construction, including an articulated spanning member  106  (or similar bridging scaffold) which spans the skull opening  126  and forms a topmost structural element, which provides protection and support to the cranial implant assembly  128 . In embodiments as shown, the articulated spanning member  106  can comprise a pair of bridging crossarms, which act as a scaffold-like structure above the skull opening  126 . In embodiments as shown, the crossarms are arranged generally perpendicular to each other, so that the two crossarms form a general X shape that extends across the skull opening  126 . It will however be appreciated that other types, shapes, or constructions of the articulated spanning member  106  can be used. 
     In general, the articulated spanning member  106  can be introduced into the area of the skull opening  126  in a non-rigid or semi-rigid, expansile, elastic, or flexible state. That expansile or elastic state can be achieved for instance using separated or articulated sub-elements held together, for example, with a guide wire, as described further herein. The articulated spanning member  106  can likewise comprise a central implant  132 , located, for instance as shown, in the center of the articulated spanning member  106 . In aspects, the central implant  132  can attach or connect to the underlying dura  104 , and create a point of rigid connection to the dura  104 , serving as a guide post from which the cranial implant assembly  128  will arrange itself on the skull defect and adapt to brain swelling and its resolution. 
     According to embodiments as shown, the cranial implant assembly  128  can likewise comprise a cover  110 , configured to be generally disposed underneath the articulated spanning member  106 . In embodiments as shown, the covering layer  110  can comprise a set of “chain-mail”—like quadrants of expansile or flexible subunits that can be held together, for example, with a set of guidewires to create a relatively flexible mesh, sheet, membrane, layer, and/or other covering construct. 
     The cranial implant assembly  128  can also comprise a peripheral attachment member  108  (or similar peripheral implant) that is configured to be attachable to the articulated spanning member  106 . In embodiments as shown, the peripheral attachment member  108  can consist of a ring-like or annular structure that is capable of being connected or attached to the bone edges of the skull opening  126 , for instance, using surgical screws or other techniques known to those skilled in the art. In aspects, the tips or ends of the articulated spanning member  106  can be generally aligned with the peripheral attachment member  108 . The articulated spanning member  106  and the peripheral attachment member  108  can be configured with a mutual locking mechanism, which permits those to elements to move into registration with each other, and to attain a rigid state. Any locking or registration mechanism known in the art can be used. In embodiments, the locking mechanism can consist of mutually aligned magnets, which attract and lock the articulated spanning member  106  and peripheral attachment member  108  when they reach sufficient proximity to each other. This registration occurs as the swelling of the dura  104  and/or brain  130  subsides, and the recession of the dura  104  begins to pull the articulated spanning member  106  in a downward direction, in embodiments shown, for example, in  FIG. 2 , the peripheral attachment member  108  can comprise four units that are configured to register into place with their ends to the ends of the two bridging crossarms. It will however be appreciated that while particular constructions of the cover  110  and the peripheral attachment member  108  are shown, other types, shapes, and constructions of those elements can likewise be used. 
     According to aspects, and also in general, the cranial implant assembly  128  can, due to the cooperation of its various elements, remain in a non-rigid, expansile, or elastic state when first implanted simultaneously with the craniectomy used to produce the skull opening  126 . In this state, both the articulated spanning member  106  and the underlying cover  110  can remain in a flexible state, in aspects because the position of the swollen dura  104  exerts pressure on those elements to remain in an expansile or elastic state. In that condition, the guidewire or other meshing mechanism used to generally align those structures remains relatively loose, and the articulated spanning member  106  and peripheral attachment member  108  do not descend or significantly descend to a lower level relative to the skull opening  126 . 
     However, as shown for instance in  FIG. 2 , as swelling in the dura  104  and/or brain  130  begins to significantly subside, the dura  104  can begin to recede toward the skull opening  126 . In aspects, the reduction in swelling in the dura  104  and/or brain  130  can be expected to begin to take place within a few days to a few weeks of time after implantation of the cranial implant assembly  128 , although the response of each individual patient will be different. In embodiments, the exertion of a downward-pulling force by the receding dura to the central implant  132  attached to the dura  104  can begin to cause a lateral force or tension to be exerted on a guidewire  116  in the articulated spanning member  106 . Particularly, the guidewire can begin to tighten a set of subunits  124  of the articulated spanning member  106 , placed next to each other and connected through the guidewire  116  to form the articulated spanning member  106 , in articulated fashion. 
     The individual subunits of the set of subunits  124  can be of any shape provided they are capable of transitioning from an expansile and/or semi-rigid state to a rigid state as the swelling of the dura  104  and/or brain  130  subsides. In embodiments, the subunits of the set of subunits  124  can be formed to have a width of approximately one-fifth of the length of each arm of the articulated spanning member  106 , or can have other sizes or dimensions. As shown, for instance, in  FIG. 3 , as the guidewire  116  tightens the set of subunits  124 , a terminal subunit  122  of the set of subunits including a magnet  112  can be drawn into proximity of a magnet  114  embedded in the peripheral attachment member  108 . Within a certain small distance, the strength of the magnetic field between magnet  112  and magnet  114  will be sufficient to lock the terminal subunit  122  into place with the peripheral attachment member  108 , and create a fixed, rigid, and/or permanent attachment or connection between the overall articulated spanning member  106  and the peripheral attachment member  108 . As this registration or locking action takes place, the cover  110  is also drawn or pressed into a position where the subunits of the cover  110  are brought into contact with each other to interdigitate, or also lock into place. 
     More particularly, and as for instance shown in  FIG. 4A , the cover  110  can comprise a set of interdigitating subunits  134  connected by a set of guidewires  118 . The set of guidewires  118  can be or include a set of wires arranged in a generally crossed or cross-hatched pattern through the rigid subunits of the set of interdigitating subunits  134 . In aspects, and as shown for instance in  FIG. 4B , the set of interdigitating subunits  134  can, again, remain in an expansile, elastic, semi-rigid, or flexible state in a type of “ripped skirt” configuration. The expansile or semi-rigid state can persist until the tension exerted on the set of interdigitating subunits  134  through the set of guidewires  118  due to the downward force of the articulated spanning member  106  being pulled toward the skull opening  126  by the central implant  132  attached to the receding dura  104  begins to draw those subunits together. The individual subunits of the set of interdigitating subunits  134  can be formed with interdigitating clasps, clips, and/or other structures to bind together once brought into contact with each other. The rigid subunits of the set of interdigitating subunits  134  can thereby lock into place and thus produce a rigid state in the cover  110  as illustrated in  FIG. 4A , after sufficient tension through the set of guidewires  118  has been applied. 
     In embodiments, it may be noted that the individual subunits of the set of interdigitating subunits  134  can be sized to be approximately one-eighth the size of each quadrant of the cover  110 , or can in embodiments be of other sizes or dimensions. It may be noted, again, that after a rigid state of the cover  110  has been achieved, both the articulated spanning member  106  and the cover  110  are now in a mechanically or structurally fixed or rigid state, providing a dome or helmet-like structure for protection of the dura  104  and brain  130 . This protective rigid construct is thus achieved without a necessity for a second surgical procedure, but instead, relying upon the ability of the cranial implant assembly  128  to transition from an expansile or elastic state to a rigid state, without further intervention after the initial implantation of the construct. 
     In the eventual rigid state achieved in the articulated spanning member  106  and cover  110 , the articulated spanning member  106  can register into a locked and permanent position with the peripheral attachment member  108 , as for instance shown in  FIG. 5A . In embodiments as shown, the terminal subunit  122  of the set of subunits  124  can slide into place on a planar face or circumferential edge of the peripheral attachment member  108 . In aspects, the terminal subunit  122  and the circumferential terminal subunit  120  can be formed with angled or chamfered edges that slide into mating position with each other. In that position, the magnet  112  and the magnet  114  are located in relatively close proximity to each other, allowing magnetic attachment or locking to take place. It will be appreciated that other registration and locking mechanisms between the articulated spanning member  106  and peripheral attachment member  108  be used, in addition to or instead of a magnetic mechanism as illustrated. 
     In terms of the sizing, fitting, and placement of the cranial implant assembly  128  and its various components in the intended surgical site, it may be noted that the area required to be covered by the cranial implant assembly  128  can be computed according to the diagram shown in  FIG. 5B . In aspects, the overall size, shape, and curvature of the patient&#39;s skull  102  can be determined by magnetic resonance imaging (MRI) or other imaging techniques. The intervening surface area, or gap, between the peripheral attachment member  108  and cover  110  can vary according to the degree of edema, distension, or swelling of the dura  104  from its normal position within the skull  102 . The desired endpoint is always to replicate the normal curvature of the skull  102 . In connection with this fitting of the cranial implant assembly  128  to the skull  102  including the skull opening  126 , areas of interest can be calculated per the following.
 
 A   3   =A   1   −A   2   Equation 1
 
 A   1 =(π r   2   1 )/2  Equation 2
 
 A   2 =(π r   2   2 )/2  Equation 3
 
 r   3   =r   1   −r   2 .  Equation 4
 
     In the preceding equations, A 1  represents the area of the dura  104  with swelling, A 2  represents the area of the dura  104  in normal curvature, and A 3  represents the area of the gap. Likewise, r 1  represents the radius of the area of the dura  104  with swelling, and r 2  represents the radius of the area of the dura  104  without swelling. 
     After computation of the correct fitting of the cranial implant assembly  128  to the intended surgical site, the cranial implant assembly  128  can be fabricated by automated and/or mechanically assisted techniques, including stereolithography. It may be noted that in embodiments, one or more components of the cranial implant assembly  128 , or the entire cranial implant assembly  128 , can be fabricated from titanium, stainless steel, bioceramic, and/or other materials. As shown in  FIG. 5B , the cuts of the set of subunits  124  can be determined by a line drawn from a middle portion of the underlying brain ventricles or canals which bisects the subunits as they cross the curvature of the overlying dura  104 . 
     It may also be noted or more components of the cranial implant assembly  128 , or the entire cranial implant assembly  128 , can be coated with an antibiotic to assist in reducing the risk of infection in the surgical site  100 . Likewise, in embodiments, one or more components of the cranial implant assembly  128 , or the entire cranial implant assembly  128 , can be coated or covered with osteoconductive periosteum, and/or other growth-promoting material, to promote the growth of replacement skull material in the skull opening  126  over the cranial implant assembly  128 . 
     It may likewise be noted that although embodiments have been described above in which the cranial implant assembly  128  is configured to include an articulated spanning member  106  consisting of two (generally perpendicular) rectangular elongated crossarms, the articulated spanning member  106  can, in embodiments, be constructed in other configuration. For example, in embodiments as shown in  FIG. 6 , the articulated spanning member  106  can be constructed as a pair of elements formed in a tapered or pyramid-like shape, with the base of the elements formed nearest to the edge of the skull opening  126 . In embodiments as shown in that figure, an expansile state can likewise be achieved using guidewires or other connective mechanisms. 
     While embodiments have also been described above in connection with a surgical site  100  involving a patient skull  102 , it may be noted in embodiments, the constructs of the present teachings can be adapted to other surgical applications. Aside from the treatment of traumatic brain injury (TBI), decompressive craniectomy, in its objective to relieve intracranial pressure, has been used in other conditions where efforts to control brain swelling medically have failed. As such, in the past, the initial emergency decompressive craniectomy has predisposed the provider to plan for an eventual late-staged cranioplasty, due to the absence of a construct that can be applied during the time of the emergency craniectomy, such as constructs according to the present teachings. 
     Among the further conditions to which implants according to the present teachings can be applied include “malignant” cerebral infarction. Cerebral infarction is a type of “stroke” (used herein as a general or umbrella term) whereby the blood supply to a major part of the brain becomes occluded and results in brain swelling. The term “malignant” as it is alluded to in the medical sense has been applied here to mean cerebral infarction which is refractory to medical treatment, and for which a surgical option (decompressive craniectomy) is recommended to avoid a fatal outcome. The multicenter pooled European randomized controlled trials (Decimal, Destiny, Hamlet, March, 2007) on application of decompressive craniectomy (DC) for malignant infarction of the middle cerebral artery (MCA) reported deconstructive cranietomy being beneficial for all the subgroups examined, resulting in recommendations for applying deconstructive cranietomy for malignant infarction emanating from US and European neurosurgical, neurological and cardiovascular professional societies. Upon survival, all craniectomized infarcted patients will need an eventual cranioplasty for cosmesis, brain protection and treatment of cerebrospinal fluid and cerebral perfusion disorders stemming from the craniectomy. 
     Further applications for constructs according to the present teachings include the treatment of brain tumors. One of the earliest uses of deconstructive cranietomy was documented by Dr. Harvey Cushing (the historically accepted father of neurosurgery) when he used deconstructive cranietomy in relieving severe cerebral edema caused by tumor removal in the brain in 1901. Cerebral swelling after tumor removal has not been an uncommon occurrence since the brain&#39;s vascular architecture, long displaced by a slow-growing tumor, usually reacts to tumor removal by going into vasospasm (reflex vessel constriction) causing diminished blood flow to the brain and consequent brain swelling. Excision of some parts of the brain may also be necessary to get to the tumor and this ablative aspect of tumor surgery itself can cause brain swelling. Upon rehabilitation, post-craniectomy cranioplasty is sought for these patients for similar purposes as described herein. 
     Additional applications for constructs according to the present teachings include epilepsy surgery. One type of seizure surgery is usually ablative, meaning a part of the diseased brain which is proven to be epileptogenic (causing seizures) is excised. The brain normally reacts to injury (ablative surgery) by swelling, which is relieved by deconstructive cranietomy. Second-stage cranioplasty is then required. 
     Still further applications for constructs according to the present teachings include the treatment of craniosynostosis—a general term for congenital anomalies causing misshapen skulls, referring to premature fusion of the skull sutures. The cranium has suture lines separating the bony plates of the skull which later fuse as the child undergoes skull molding during growth. Suture lines may prematurely fuse or even fuse asymmetrically, causing a misshapen skull. The final skull shape will depend on which suture line(s) prematurely fuse. Those various conditions or deformities are given descriptive names ending with -“cephaly,” e.g. scaphocephaly (canoe-head), brachycephaly (clover-leaf head), turricephaly (tower skull), etc. Correction and repair of these misshapen skulls require partial or full craniectomy for purposes of cosmesis (to address social dysfunction), impending mental retardation, or impending visual problems caused by shifting intracranial pressure rises due to the misshapen skull.  FIG. 7  illustrates conventional treatment of an enlarged cranial vault in a child with hydrocephalus, in which a craniectomy is performed to produce multiple separated skull sections. In this conventional approach, a shunt valve may also be introduced to assist in reducing intracranial pressure. 
       FIG. 8  illustrates a cranial implant assembly  228  that may be directed to the treatment of children having hydrocephalus, according to further various embodiments of the present teachings. In embodiments as shown, the pediatric patient can have an enlarged cranial vault due to the effects of hydrocephalus. In embodiments as shown, the cranial implant assembly  228  can comprise an articulated spanning member  206  whose multiple guide arms are snugly applied in strap-around fashion to the patient skull, to produce surgical skull shape correction. A set of central implants  232  can be attached or connected to the underlying dura (not shown), which set of central implants  232  serve to hold a cover  210  in place over the various skull openings or fissures produced by the multi-part or multi-section craniectomy. The cover  210  can comprise a multi-part expansile, flexible, and/or semi-rigid cover or layer each section of which has a set of subunits  234 , which can be a set of interdigitating subunits similar to those described in embodiments above. The set of subunits  234  can be connected via a set of guidewires (not shown) in articulated fashion, likewise as above. In aspects, the cranial implant assembly  228  can be configured to transition to an eventual rigid state through the tensioning and locking of the cover  110  and articulated spanning member  206  to a magnetic peripheral member (not shown) or other attachment site, in a manner generally similar to or using mechanisms like those described above. In aspects, a shunt valve  214  may also be inserted to assist in regulating intracranial pressure. Various embodiments of the present teachings including those shown in  FIG. 8  will expedite the usually long period of operation needed in repairing the skull anomalies in pediatric patients, a vulnerable group. Some of the types of craniosynostosis that can be treated using these inventive constructs are part of a syndrome known by different names (Crouzon&#39;s syndrome, etc.). 
     According to yet further aspects, embodiments of the constructs of the present teachings can be used to treat other skull shape anomalies which are not congenital, but which may still require deconstructive cranietomy for repair. Those anomalies include positional ones, such as plagiocephaly (flat-headed condition) that is usually caused by poor child care when the child is left on the supine position for a long time, and the back head is positioned against a flat firm surface Those anomalies likewise include hydrocephalic megacephaly, or the condition of a large skull for infant/child&#39;s size caused by an underlying hydrocephalus (cerebrospinal fluid, or CSF disorder) where the amount of CSF produced is not absorbed by the body but accumulates in the brain. This results in a relatively rapid increase in skull size and separation of the still unfused suture lines. Aside from a shunting procedure which diverts the accumulated CSF for absorption, a cranial vault reduction cranioplasty is done to correct skull shape. Constructs according to embodiments of the invention may expedite repair in this condition, as well. 
     It will again, however, be appreciated that surgical constructs according to embodiments of the present teachings, and/or adaptations of those constructs, can be used in even further applications, including to treat other cranial conditions besides those directly noted herein, and/or to treat and heal conditions of other bone structures, tissues, organs, and/or areas of the body. 
     The foregoing description is illustrative, and variations in configuration and implementation may occur to persons skilled in the art. For example, while embodiments have been described in which the articulated spanning member  106  consists of two generally perpendicular crossarms or other structural elements, in embodiments, three, four, and/or other numbers or crossarms can be used, for instance, divided in a hemispherical pattern or arrangement over the skull opening  126 . For further example, while embodiments have been described in which the cover  110  is sub-divided into four quadrants or regions, in embodiments, the cover  110  can be divided into other numbers or types of sections or regions. Other elements or resources described as singular or integrated can in embodiments be plural or distributed, and elements or resources described as multiple or distributed can in embodiments be combined. The scope of the present teachings is accordingly intended to be limited only by the following